COMPRESSORDedicated To Gas Compression Products & Applications

TargeTing The Large CPi’s newEmissions AsU RAcE PRoflo Eos

OCTOBER 2013

New Valve DesignTargets Recips

Fixed-Speed Compressorsfor offshore

StationaryEmissions-At-A-Glance

www.compressortech2.com

Foun

datio

nTECHNOLOGY

Oct_C1.indd 1 9/24/13 1:52 PM

HOERBIGER Engine Solutions

Click on company logo to see ad page

This issue Driven By

Power & Compression

CT_Oct_DrivenBy.indd 1 9/25/13 11:23 AM

n Customer: Refinery, Louisiana, USA.

n Challenge: Increase reliable, on-site power generation within the plant’s existing carbon footprint.

n Result: An Elliott 36 MW FCC hot gas expander-generator converts refinery waste gas to electrical power.

They turned to Elliottfor “green,” reliable power.

The customer turned to Elliott because of our 50 years of experience and nearly 500 MW of installed capacity in FCC power recovery. Elliott TH expanders routinely operate 5 years and more between shutdowns, extending FCC maintenance cycles and reducing maintenance costs. Who will you turn to?

C O M P R E S S O R S n T U R B I N E S n G L O B A L S E R V I C Ewww.elliott-turbo.com

The world turns to Elliott.

ElliottGroup.indd 1 8/15/13 9:11 AM

WORLD STANDARDCOMPRESSORS

740.397.0311 | 35 Blackjack Rd Mount Vernon, OH 43050 | www.arielcorp.com

KBZ/6

Compressor packages are designed around a compressor. Choose Ariel and have your package designed around the most reliable and best supported compressor available.

Contact Ariel today through one of our distributors, arielcorp.com, or Ariel7-2Go, and let us help you specify the right compressor for your application.

There’s A Reason Why It’s Called A Compressor Package

Ariel_CT2_Oct_13_final.indd 1 9/11/13 11:55 AMAriel.indd 1 9/12/13 10:14 AM

TechTransfer_CT2.indd 1 2/22/12 9:11 AM

TechTransfer_CT2.indd 2 2/22/12 9:11 AM

Rather recently, Stefan Gillessen has called our attention to a monster black hole in the center of our galaxy. He is with the Max Planck Institute for Extra-terrestrial Physics in Garching, Germa-ny. This black hole is some 26,000 light years away, so that the phenomenon being observed in its surroundings hap-pened some 26,000 years ago. It’s also nearly 152,508,096,000,000,000 miles (245.4 x 1015 km) away. Somehow, I feel a bit isolated from the event. Yet, it is by far the closest black hole to our solar system and provides much more detail than any other black hole being observed — great.

Presently — if 26,000 years can, in any stretch of the imagination, be considered in the present — the black hole is observed consuming a gas cloud that is about some 37 bil-lion miles long (60 billion km). It has a gravitational field of 4 million suns. It has been sweeping up space material for more than a million years.

For those wondering about black holes, they are large stars that have died and collapsed into themselves, re-sulting in a major reduction in volume. If the mass of the earth would go through the same phenomenon, it would shrink to the size of a marble that you could hold in your hand. (If you could lift it.) Black holes suck up everything that falls within their intense gravitational field.

Scientists are still trying to confirm the existence of dark matter. Their claim is that dark matter makes up some 25% of the universe while about 70% is made up of the little-understood dark energy and about 5% is mat-

ter composed of atoms. Scientists think that dark matter is made up of WIMPs, defined as “weakly interact-ing massive particles.” WIMPs can be found just about anywhere, scientists suppose. To find them, scientists look in deep mines, in particle smashups in colliders and also in space. They are elusive little buggers and the as-sumption is that billions of them may be zipping through the earth without touching anything.

Okay, where are we going with this? The thought crossed my mind that this darkness could be allegorically related to our national debt and our foreign policy. The former sucks the oxygen out of our economy and the latter is so elusive that it seems to flit around with-out touching anything. Does it exist?

On the brighter side, COMPRESSOR tech2 is entering the fourth quarter of 2013. We have some interesting edito-rial plans for the remainder of the year. By now, you should be acquainted with October’s feature article content, which includes interesting studies on emissions and foundations. No-vember will carry information re-garding ignition, compressed natu-ral gas products and systems, plus failure detection and analysis. Top-ping it off, in December we will ad-dress the subjects of turboexpanders and shaft alignment. That issue also will contain our annual Executive Out-look, which gives senior managers a forum to discourse on past and future compression industry performance.

While digesting all this, may the Lord hold you in the hollow of His hand. CT2

Darkness Seems To Dominate Our Consciousness

Page4President & CEO .................... Michael J. OsengaExecutive Vice President ...Michael J. Brezonick

PUBLICATION STAFFCT2 Founder .......................... Joseph M. KanePublisher .................................Brent D. HaightAssociate Publisher ..............Roberto ChelliniEditor ..........................................Patrick CrowExecutive Editor .............................. DJ SlaterSenior Editor ................. Michael J. BrezonickSenior Editor ............................. Mike RhodesAssociate Editor ............................... Jack BurkeAssociate Editor ............................Chad ElmoreCopy Editor ............................... Jerry Karpowicz

Digital Content Manager ...........Catrina Boettner

Circulation Manager ..................Sheila LizdasProduction Manager ............ Marisa J. RobertsGraphic Artist .......................Brenda L. BurbachGraphic Artist ............................Carla D. LemkeGraphic Artist .......................... Amanda J. RyanGraphic Artist ............................... Alyssa Loope

PUBLICATION HEADQUARTERS20855 Watertown Road, Suite 220Waukesha, Wisconsin 53186-1873

Telephone: (262) 754-4100 Fax: (262) 754-4175

CONTRIBUTING EDITORSEllen Hopkins - Midland, TexasNorm Shade - Cambridge, Ohio

Mauro Belo Schneider - Rio Grande du Sul, Brazil

HOUSTON OFFICEBrent D. Haight, Publisher

Patrick Crow, EditorMike Rhodes, Senior Editor

12777 Jones Road, Suite 225Houston, Texas 77070

Telephone: (281) 890-5310 Fax: (281) 890-4805

GERMAN OFFICELisa Hochkofler, Advertising ManagerGabriele Dinsel, Advertising Manager

Niemöllerstr. 973760 Ostfildern, Germany

Telephone: +49 711 3416 74 0 Fax: +49 711 3416 74 74

UNITED KINGDOM OFFICEIan Cameron, Regional Manager/EditorLinda Cameron, Advertising Manager

40 Premier Avenue Ashbourne, Derbyshire,

DE6 1LH, United Kingdom Telephone: +44 20 31 79 29 79 Fax: +44 20 31 79 29 70

ITALIAN OFFICESRoberto Chellini, Associate Publisher

44, Via Delle ForbiciI-50133 Firenze, Italy

Telephone: +39 055 50 59 861 Fax: +39 055 57 11 55

Roberta Prandi Via Fitta, 21a

I-38062 Arco, ItalyTelephone: +39 0464 014421 Fax: +39 0464 244529

SCANDINAVIAN OFFICEBo Svensson, Field Editor/Business Manager

Dunderbacksvagen 20612-46 Finspong, Sweden

Telephone: +46 70 2405369 Fax: +46 122 14787

JAPANESE OFFICEAkiyoshi Ojima, Branch Manager

51-16-301 Honmoku Sannotani, Naka-kuYokohama, 231-0824 Japan

Telephone: +81 45 624 3502 Fax: +81 45 624 3503

CHINESE OFFICES.H. Mok, Branch ManagerRm 1405, Kowloon Building

555 Nathan RoadKowloon, Hong Kong

Telephone: +852 3118 7930 Fax : +852 3110 3572

COMPRESSORA Member of the Diesel & Gas Turbine Publications Group

JOE KANECOMPRESSORtech2

Founder

CT270.indd 1 9/23/13 10:01 AM

Reliable SwiSS Quality

API 618Rod load up to 1’500 kN/335’000 IbsPower up to 31’000 kW/42’100 HP

Full Range:

You get moRe than Just a PRocess gas comPRessoR

Lubricated up to 1’000 bar, non-lubricated up to 300 bar

For highest availability: We recom-mend our own designed, in-house engineered compressor valves and key compressor components

Designed for easy maintenance

We are the competent partner with the full range of services – worldwide

→ www.recip.com/api618

YouR BeneFit: lowest liFe cYcle costs

Visit us → at ADIPEC, Abu Dhabi, 10 –13 Nov,

Hall 6, Booth 6310

Burckhardt_API.indd 1 9/9/13 1:50 PM

Follow Compressortech2

at www.compressortech2.com

MEMBER OF BPA WORLDWIDE®PRINTED IN THE U.S.A.

MEMBER OF …

Compressortech 2 ( ISSN 1085-2468) Volume 18, No. 8 — Published 10 issues/year (January-February, March, April, May, June, July, August-September, October, November, December) by Diesel & Gas Turbine Publications, 20855 Watertown Road, Waukesha, WI 53186-1873, U.S.A. Subscription rates are $85.00 per year/$10.00 per copy worldwide. Periodicals post-age paid at Waukesha, WI 53186 and at addi-tional mailing offices. Copyright © 2013 Diesel & Gas Turbine Publications. All Rights Reserved. Materials protected by U.S. and international copy-right laws and treaties. Unauthorized duplication and publication is expressly prohibited. Canadian Publication Mail Agreement # 40035419. Return Undeliverable Canadian Addresses to: P.O. Box 456, Niagara Falls, ON L2E 6V2, Canada. E-mail: slizdas@dieselpub.com. POSTMASTER: Send address changes to: Circulation Man ager, Compressortech2, 20855 Watertown Road, Suite 220, Waukesha, WI 53186-1873 U.S.A.

Featured Articles 16 MAN’s MGT6200 Enters Commercial Operation

20 New Valve Design Targets Recips

38 Advanced Materials Improve Wiper Packing Performance

42 Converting Natural Gas Starting System To Air Cuts Emissions

46 Eliminating Excessive Compressor Lubrication

50 Stationary Emissions-At-A-Glance

54 Effective Foundations, Anchor Bolts And Grouting For Recips

72 The Large ASU Race

TECHcorner 24 Compressor Foundation Analysis Tool

74 Stepless Capacity Control For Recips

80 Fixed-Speed Compressor Drivers For Offshore Platforms

Departments 4 Page 4 — Darkness Seems To Dominate Our Consciousness

8 Global Perspective — Nigeria Could Double Its LNG Production

10 Meetings & Events

12 About The Business — Liquids-Rich Plays, Gas Lift Help Keep

Compression Business Solid

14 Monitoring Government — What Happened Next

52 Recent Orders

52 Prime Movers

78 Literature

90 Advertisers’ Index

91 Featured Products

92 Scheduled Downtime

93 Marketplace

96 Cornerstones Of Compression — Solar’s Centaur Gas Turbine

COMPRESSORDedicated To Gas Compression Products & Applications

OCTOBER 2013

Cover Designed By Alyssa Loope

CT2_October_TOC.indd 1 9/24/13 3:35 PM

Industrial engines rarely rest, pumping out power hour after hour. That 1,000 hp engine would have filled the USS Macon airship of 1933 with 6 1/2 million cubic feet of helium in just 20 hours.

But of course power isn’t the only thing these engines put out. To handle the resulting emissions demands a catalyst of equal durability, one that can remove 6 tons of Carbon Monoxide and Oxides of Nitrogen every 1000 hours.

It is not surprising, then, that more and more companies are turning to the global leader in the research, design, engineering and manufacturing of advanced emission control technologies: DCL International. And that’s not just hot air either.

877.897.9759 dcl-inc.com

AND THAT’S NOT JUST HOT AIR.

A 1,000 HP ENGINE GENERATES 332,000 CU. FT. OF EXHAUST

EVERY HOUR.

D a l l a s • H o u s t o n • l o s a n g e l e s • o k l a H o m a C i t y

DCL_HotAir_WW.indd 1 1/24/13 9:13 AM

OCTOBER 2013 8 COmpREssORtech2

In spite of agreements among international oil compa-nies and environmental authorities to reduce and ban natural gas flaring, this practice is still very much in use

in several nations.In Nigeria, more than 50% of the gas coming to the sur-

face, mostly associated with oil production, is flared, shrinks or is reinjected in the oil wells. Reducing flaring, which is a real waste and is harmful to the environment, would require the construction of a network of pipelines and compressor stations that national oil companies cannot always afford. The more lucrative oil production induces many state-owned companies to just get rid of the associated gas by burning it, although the practice is a waste of energy and revenues.

Nigeria’s gas market has grown significantly since opening of the Bonny Island liquefied natural gas (LNG) terminal in 1999. Marketed gas production has increased steadily since then, reaching 1.45 Tcf (41 x 109 m3) in 2011, according to the Organization of Petroleum Exporting Countries. (The U.S. En-ergy Information Administration’s estimate is more conserva-tive.) The growth in gas output has not resulted in a noticeable reduction in flaring or shrinking, bringing total gross production to more than 2.9 Tcf (84 x 109 m3). Nigeria therefore could have the potential to nearly double its LNG exports if it were to reduce the current amount of gas wasted.

The Olokola LNG (OKLNG) project was set to capitalize on currently wasted volumes. State-owned Nigerian Na-tional Petroleum Corp. (NNPC) signed a US$6 billion LNG agreement with several international oil companies, includ-ing Chevron, Shell and BG, in July 2005 for OKLNG to come onstream in 2012. The terminal was initially planned to have four LNG trains of 268 Bcfy (7.59 x 109 m3/yr) each with a total production of 1 Tcf (30.4 x 109 m3) and also pro-duce substantial quantities of gas liquids as a by-product.

Chevron and Shell announced in late August they were withdrawing from the project, following BG, which had made the same decision in 2012. The exit of the remaining inter-national partners means that NNPC is unlikely to develop OKLNG on its own, according to Business Monitor Inter-national (BMI). Although NNPC has announced that it will move forward with the project, BMI expects that NNPC will be forced to turn its attention toward more reliable develop-ments, leaving OKLNG on hold.

The withdrawal of the international oil companies under-scores the growing dissatisfaction that investors have with respect to Nigeria’s business environment. Both Chevron and Shell justified their decision on the lack of progress in the project rather than potential profitability and availability of gas feedstock.

OKLNG has faced numerous issues since the project was proposed in 2005. In particular, it faced sabotage threats from Niger River Delta militants who wanted the Brass LNG invest-ment decision to be given priority, in order to first develop the Bayelsa State instead of the Lagos area in western Nigeria.

As the project advanced, the Joint Revolutionary Council made direct threats against Shell and Chevron, local infra-structure and the local work force based on the fact that the companies would be contributing to the rapid degradation of the environment and agricultural lands.

This decision could also result in a serious blow to Nige-rian President Goodluck Jonathan’s natural gas develop-ment program, as it illustrates that the government has not been doing enough to ensure investors will face suitable business conditions. The plan includes not only the devel-opment of midstream and power generation infrastructure, but also building the Brass LNG terminal. Partners on this project include NNPC, Eni and Total.

Signs of progress on Brass came in mid-2011 when bids were opened for the engineering, procurement and con-struction work. However, momentum has seemingly stalled and the final investment decision, previously expected at the beginning of 2013, is still pending.

With ConocoPhillips withdrawing from the project earlier this year, Brass LNG appears worryingly similar to OKLNG and BMI sees a growing downside risk to its development. However, NNPC will certainly provide substantial support to this project now that OKLNG seems unlikely to advance.

BMI expects Nigeria’s LNG exports to remain below 1 Tcf (30 x 109 m3) at least until 2022. Additional gas for exports will come from the revived West African Gas Pipeline, but there is little potential for other growth given the concerns already expressed by LNG importers regarding the unreliability of ex-isting Nigerian supplies. Most of the rise in production will be directed toward meeting growing domestic demand, since Ni-geria increasingly relies on gas-fired power generation. CT2

Nigeria Could Double Its LNG Production > By ROBERTO CHELLINI

ASSOCIATE PUBLISHER

Global Perspective

But foreign investors are growing wary of new projects

CT262.indd 1 9/24/13 9:38 AM

They may display a proud old name on the outside, but the driving force within the world’s best-engineered, most efficient, pipeline gas compressors is Rolls-Royce. The heritage name, Cooper-Bessemer, still carried by older machines, echoes the engineering excellence that has

earned Rolls-Royce an unparalleled reputation for quality. Today, in a business where productivity and dependability mean so much, the unsurpassed engineering experience of the past makes Rolls-Royce the compressor name of the future.

A proud past leads to a new future

Trusted to deliver excellence

It’s all in the name...

Cooper-Bessemer is a registered trade name of Cameron Corporation, used under license by Rolls-Royce plc

www.rolls-royce.com

RollsRoyce_BessAd.indd 1 1/31/12 4:39 PM

Meetings & Events*Indicates shows and conferences in which Compressortech2 is participating

For a complete listing of upcoming events, please visit our website at www.compressortech2.com

OctOberOct. 6-9*Gas Machinery conference — Albuquerque, New MexicoTel: +1 (972) 620-4026Web: www.gmrc.org

Oct. 7-10*Argentina Oil & Gas expo — Buenos Aires, ArgentinaTel: +54 11 4322 57Web: www.aog.com.ar

Oct. 10-12China (Beijing) International Petroleum Technology Conference & Exhibtion — BeijingTel: + 86 10 6273 0706 Web: www.ciptc-top.com

Oct. 22-24*Louisiana Gulf Oil & Gas exposition — Lafayette, Louisiana Tel: +1 (337) 235-4055Web: www.lagcoe.com

Oct. 28-30

Shanghai International Petroleum

Petrochemical Natural Gas Technology

Equipment Exhibition — Shanghai

Tel: + 86 21 36411666

Web: www.sippe.org.cn/en

Oct. 28-31

International Rotor Dynamics

Seminar — Cologne, Germany

Tel: +49 2267 6585-0

Web: www.arla.de

Oct. 30-Nov. 1

EP Shanghai 2013 — Shanghai

Tel: +86 10 5129 3366

Web: www.epchinashow.com

NOveMberNov. 10-13

*Abu Dhabi International Petroleum

exhibition & conference —

Abu Dhabi, United Arab EmiratesTel: +971 2 4444 909Web: www.adipec.com

Nov. 12-14*Power-Gen International — Orlando, FloridaTel: +1 (918) 831-9736Web: www.power-gen.com

Nov. 13-15Developing Unconventional Gas (DUG) East Conference & Exhibition — PittsburghTel: +1 (713) 260-5209Web: www.dugeast.com

DeceMberDec. 5-8Basra Oil & Gas Conference and Exhibition — Basra, IraqTel: +90 212 356 00 56 (1725)Web: www.basraoilgas.com

Meetings & Events

Season change without downtime. TurboCool – reliable cooling power control.

The Voith TurboCool eliminates fan blade repitching by adapting the cooling power to your needs via active fan speed control. This reduces CO2 emissions, as well as prevents freeze-ups and overheating. It reduces noise,

raises production and availability and protects the drive line.

+1 717-767-3200

+1 905-670-3122

Voith.indd 1 5/22/13 2:31 PMoct_meetingsevents.indd 1 9/23/13 10:14 Am

Meetings & Events

For a complete listing of upcoming events, please visit our website at www.compressortech2.com

JANUARY 2014Jan. 21-23Offshore West Africa — Abuja, NigeriaTel: +1 (713) 963 6283Web: www.offshorewestafrica.com

FebRUARYFeb. 4-7*Gas/electric Partnership Conference — Cypress, TexasTel: +1 (713) 529-3216Web: www.gaselectricpartnership.com

Feb. 19-21Australasian Oil & Gas Conference — Perth, AustraliaTel: +61 3 9261 4500Web: www.aogexpo.com.au

Feb. 24-27Nigeria Oil & Gas Conference — Abuja, Nigeria

Tel: +44 20 7978 0000Web: www.cwcnog.com

MARCHMarch 19-21China International Offshore Oil & Gas Exhibition — BeijingTel: +86-10-5823 6555Web: www.ciooe.com.cn/2014/en

March 23-27 *Sour Oil & Gas Advanced Technology 2014 — Abu Dhabi, United Arab EmiratesTel: +971-2-674-4040Web: www.sogat.org

March 24-25*Gas Transport & Storage 2014 — Berlin, GermanyTel: +44 20 7202 7690Web: www.gtsevent.com

March 26-27Georgian International Oil, Gas, Energy

*Indicates shows and conferences in which Compressortech2 is participating

and Infrastructure Conference — Tbilisi, GeorgiaTel: +44 207 596 5135Web: www.giogie.com

APRilApril 7-9*Gas Compressor Association expo & Conference — Galveston, TexasTel: +1 (972) 518-0019Web: www.gascompressor.org

*April 9-10Turkish international Oil and Gas Conference 2014 — Ankara, TurkeyTel: +44 207 596 5147Web: www.turoge.com

*April 13-16Gas Processors Association Annual Convention — DallasTel: +1 (918) 493-3872Web: www.gpaglobal.org

isn’t always better.

innovative emission solutions™

800.640.3141 | miratechcorp.com

Stay clean.

investing in durable clean air

solutions keeps your emissions in

compliance year after year. that’s

an roi everyone can appreciate.

MIratech.indd 1 5/7/13 1:34 PM

oct_meetingsevents.indd 2 9/24/13 3:39 pm

OctOber 2013 12 cOmpressOrtech2

Gas compression equipment shipments in the first half of 2013 reached the highest volume since the 2008 boom. But order rates leveled off as compres-

sion fabrication and contract services companies reported mixed results.

Exterran Holdings reported that fabrication revenues for the second quarter were up 71% from the corresponding period in 2012 but were flat from the first quarter.

Contract compression revenues were up 5 and 8%, re-spectively, for the same periods. Exterran’s second-quarter earnings were the highest in four years, benefiting from cus-tomers exercising purchase options in the North America and international contract operations business segments.

Enerflex’s second-quarter revenue was down 11% from the first quarter and 12% from the second period of 2012. Southern United States, Latin American and international business was strong. But activity was lower in Canada and the northern U.S., causing Enerflex to close its Casper, Wy-oming, packaging facility.

Bidell Compression (Total Energy Services Inc.) reported a 59% increase in compression and process equipment sales compared to a relatively weak second quarter in 2012. Dresser-Rand’s new unit revenues were 46.3% higher in the second period than a year earlier, reflecting variability in the timing and size of some large orders.

Rolls-Royce Energy Systems’ revenue was up 10%, but Caterpillar Power Systems and Cameron Process and Compression sales were 5 and 8% lower, respectively, for the same period. Arrow Engine (Trimas) revenue was down 4%. Packaged unit sales for Natural Gas Services Group (NGSG) were down 9%.

Along with Exterran, most contract compression compa-nies reported growth. NGSG rental revenues were up 17% from a year ago and 7% for the quarter. USA Compression Partners reported contract revenues up 15% over the sec-ond quarter of 2012. Compressco’s services revenues were up 13%, compared to the corresponding period last year, due to higher utilization in the U.S. Most companies ben-

efited from applications such as gas lift in attractive uncon-ventional resource plays, uses that encourage higher rents and utilization rates.

Rental fleet utilization for the industry as a whole is at the highest level since 2007. After disposing of many older units in the last few years, industry leader Exterran grew its fleet to 4,669,000 hp (3,482,000 kW) in the second quarter, 2.9% over that period in 2012. However, utilization dropped slightly from 83.9 to 82.8%.

USA Compression’s fleet increased by 12.7% from June 30, 2012 to 968,178 hp (721,982 kW) this June 30. Utiliza-tion held solidly in the 93 to 94% range. USA’s acquisition of S&R Compression gave it another 983 units and 138,000 hp (102,908 kW) in August 2013.

NGSG’s fleet utilization increased to 79%, with more than 35% installed in oil- or liquid-oriented basins. Compressco’s utilization recovered to 82.6%, despite a larger than antici-pated decline in Mexico. Bidell continues to build a small fleet, now totaling 30,500 hp (22,744 kW) on contract with an 84% utilization rate.

Although new compressor package orders leveled off for the industry as a whole, business remained at a healthy level for most companies. With significant packaging capac-ity added in the last year, backlogs have declined and lead times are shorter.

Bidell recovered from a weak second quarter in 2012 with a backlog increase of 106%. Enerflex’s order bookings were up 19% during the second quarter, compared to that period in 2012. Backlog declined 25% from the same point last year but increased 15% over from the first quarter of this year.

With softer bookings, Exterran’s compressor fabrication backlog declined 4% from the first quarter of 2013 and 35% from the second period of 2012. Dresser-Rand’s new unit bookings for the second quarter were 25% higher than the same period a year ago, even after a major order cancel-lation. Its backlog increased 2.7%, but Dresser-Rand tem-pered its full-year forecast somewhat, noting that upstream projects are being delayed by customers’ resources and capital expenditures constraints.

Rolls-Royce Energy Systems orders were 1% higher compared to the second quarter of 2012. Cameron Process and Compression orders were down 25% and backlog was down 17% from a strong second quarter in 2012. CT2

Liquids-Rich Plays, Gas Lift Help Keep Compression Business Solid > By NoRM SHADE

About The Business

But flattening order rates raise a note of caution

By NoRM SHADE

Norm Shade is senior consultant and president emeritus of ACI Services Inc. of Cambridge, Ohio. A 43-year veteran of the gas compression industry, he has written numerous papers and is active in the major industry associations.

CT266.indd 1 9/23/13 10:17 AM

evolving solutions around your world

www.c-p-i.com/lubrication/monitoring-devices/proflo-eos/

come and see for yourself at the Gas Machinery

Conferencebooth119

Never before have lubricated compressors been so well protected by innovation.

cpi-CT2 ad-oct13 eos -final.indd 1 16/09/2013 17:02CPI.indd 1 9/17/13 10:38 AM

Monitoring governMent

Revisiting some compression-related controversies

By PatRick cRow

What Happened Next >

OCTOBER 2013 14 COmpREssORtech2

it’s a bit annoying when you realize that you recently read a news article on a subject — and then never saw a fol-low-up story. Did you overlook it, or was it even written?

over the past year, this column has reported about how governments have responded to some issues directly or indirectly affecting the compression industry. For those ar-ticles, anyway, here’s the rest of the story.

Last october, the column’s topic was a pending Envi-ronmental Protection agency rule to lower emissions from stationary reciprocating internal combustion engines. it was the most important federal regulation to hit the compression industry for some time.

the January-February column followed up with the details of the final rule. issues remain regarding compliance with the regulation’s Quad o, Quad Z and vapor recovery sections.

the November column discussed cyber attacks on gas pipelines. Sen. Jay Rockefeller had drafted legislation to create a federal-private panel to promote better security standards for critical infrastructure, including pipeline com-pressor stations. when the west Virginia Democrat could not get his bill passed, he urged President Barack obama to do the same thing through an executive order.

and obama did. in February he instructed the Depart-ment of Justice and the office of the Director of National intelligence to share more data on cyber attacks with infra-structure operators. the order also created a government-industry group to draft standard practices for improving cy-ber security in the private sector.

in December the subject was Pennsylvania’s controver-sial act 13, which decreed that local governments could not impose standards on oil and gas activities beyond those re-quired by state law — a key concern for companies building pipelines and compressor stations for the growing volumes of Marcellus Shale gas.

anti-act 13 lawsuits were promptly filed and appealed to the state’s supreme court. the resignation of a justice de-layed the court’s review but a replacement has now been seated. Meanwhile, Gov. tom corbett fired Richard allan, the head of the Department of conservation and Natural Resources, who had been a lightning rod for complaints.

the March column focused on another political hot po-tato: whether to allow the export of surplus U.S. natural gas.

So far the Department of Energy (DoE) has approved three licenses, but 20 more applications are pending.

DoE’s permitting stalled late last year as it reviewed thousands of public comments on its decision process. the interregnum following Energy Sec. Steven chu’s resigna-tion extended the inaction. Now, Sec. Ernest Moniz has pledged quicker action on the remaining applications.

in april the topic was the European Union’s troubled Emissions trading Scheme for greenhouse gas allow-ances. a glut has depressed prices for the permits and thwarted the program’s goal of promoting low-emission industrial projects.

the European Parliament subsequently voted to defer the auction of new permits in order to increase the value of the existing ones. the “backloading” plan will face stiff op-position when European nations vote on it.

the May column was about colorado Mountain col-lege’s disavowal of an agreement to let SourceGas to build a US$14 million compressor station on the edge of its cam-pus near Glenwood Springs.

the gas distribution company sued the community col-lege to enforce the deal, lost in court, then sued for reim-bursement of development expenses, and lost again. it since has found another site for the station.

in June the column discussed Mexico’s need to develop its vast shale gas resources using a state-owned company, Petróleos Mexicanos, which just wasn’t up to the job.

President Enrique Peña Nieto subsequently proposed, as detailed in the august-September column, to end Pe-mex’s monopoly. Under the plan, Pemex would partner with international oil companies to leverage the capital, technology and expertise to develop Mexico’s shale and deep-sea resources.

the July column was about North Dakota’s efforts to reduce the flaring of gas at wellheads. about 28% of the state’s gas output is burned (a side effect of the Bakken Shale oil drilling boom) compared to only 1% nationwide.

State officials are losing patience. the North Dakota industrial commission, which is chaired by the governor, recently ordered the director of the Mineral Resources De-partment to warn producers and pipeliners that if industry doesn’t damper flaring, tougher regulations will ensue. Ct2

ct268.indd 1 9/23/13 10:19 aM

Call your nearest MOTORTECH Sales Partner!

MOTORTECH AMERiCAS LLC. | www.motortech.de | www.motortechamericas.com | Worldwide distribution

Distribution partner for DENSO spark plugs

Call your nearest MOTORTECH Sales Partner:

Cypress Engine AccessoriesPhone: 1-281-256-9100www.cypressengine.com

Martin Machinery L.L.C.Phone: 1-660-458-7000sales@martinmachinery.com

Reagan Equipment Company Toll free: 1-800-254-7767 www.reaganpower.com

FROM THE PICKUP TO THE PLUG!

MOTORTECH and its global Distributors provide the important products that ensure your gas engine runs when you need it.

MiC4 Powerful ignition controller – Double your ignition energy!

AlphaRail Durable wiring rails

MotCoils High performance ignition coils

DetCon20 Reliable knock detection and control

Pickups For all common gas engines

Note: The whole system is more than the sum of its parts!

All t

rade

mar

ks, l

ogos

, and

sym

bols

are

exc

lusi

ve o

bjec

ts to

the

righ

t of t

heir

ow

ners

and

are

use

d fo

r ref

eren

ce p

urpo

se o

nly.

2013-09-13-CT2_Oktober.indd 1 17.09.13 11:12Motortech.indd 1 9/17/13 10:32 AM

MAN Diesel & Turbo (MDT) an-nounced the development of its MGT6200 gas turbine at

the end of 2010. After the shop test-ing program concluded, the two-shaft prototype was assembled at the SolVin chemical plant in Rheinberg, Germany.

The plant is 18 miles (30 km) from MDT’s Oberhausen headquarters. SolVin, a joint venture of Solvay and BASF, makes polyvinyl chloride for the world marketplace.

The MDT-SolVin relationship started several years ago when MDT supplied SolVin with a twin pack featuring two FT8 gas turbines to produce 67,000 hp (50 MW) of power to use in the process.

The installation of the MGT6200 at the combined heat and power (CHP) plant created a win-win situation. MDT was looking for a site near to its Oberhausen headquarters to install the prototype and gather data under

operating conditions. SolVin, with the production of the additional 8000 hp (6 MW), got complete independence from the external power grid (avail-able in case of maintenance or emer-gency) and supplemented by 5% its process steam network.

The installation of a two-shaft gas turbine in a CHP plant is not common, but MDT started the development of the new gas turbine in the two-shaft config-uration because the machine is primar-ily intended for compressor drive. The single-shaft version is on the MDT test stand undergoing final prototype tests.

The two-shaft prototype also allows a more flexible and wider operating field for the possibility of variation of the power turbine speed independently from the high-pressure turbine shaft.

On offshore platforms, where gas turbine-driven compressors are in-stalled, in case of need for more elec-

tric power the operator may select a two-shaft turbine to drive the generator in order to streamline spare parts inven-tory and maintenance operations.

The SolVin CHP plant consists of the gas turbine-generator package in-stalled in an open site and protected by a waterproofed lagging. The gen-erator is coupled, through a gearbox, to the power shaft (hot end) of the gas turbine. Two containers house all the water equipment (demineralization plant, water feed pumps, etc.). The boiler is mounted on the gas turbine lateral exhaust line without a bypass stack but there is space for one if the process needs it.

For the time being SolVin is using all the steam produced at 174 psi (12 bar), 500°F (260°C) in the net-work feeding the various processes. A pressure reduction station receives

MAN’s MGT6200 Enters Commercial Operation > Two-shaft turbine was designed to

drive compressors

n The MGT6200 in the two-shaft configuration, shown in this 3-D illustration, was mainly developed for the mechanical drive of compressors and pumps.

OCTOBER 2013 16 COmpREssORtech2

By ROBeRTO CHelliNi

continued on page 18

CT273.indd 1 9/23/13 10:24 AM

KB_Delta_June.indd 1 5/23/13 8:10 AM

natural gas from the local pipeline at 580 psi (40 bar) and lowers it to 319 psi (22 bar) as required by the MGT6200 fuel system.

The local control room is inside a container located on the cold side of the main package. It is possible to start, operate and stop the plant lo-cally, but during normal operation the plant is monitored from the plant’s central control room. The local control room remains unattended.

Because the Rheinberg installation also is a testing site, an Internet link allows MDT’s Oberhausen headquar-ters to access all operating data. This link was permanently open during the testing period. After commissioning the link can be opened if the custom-er need special information or help in case of problems.

MGT6200 gas turbineThe MGT6200 type industrial gas

turbine was developed by MDT mainly for mechanical drive of its compressors and for power generation applications.

Its introductory rating is 8314 hp (6.2 MW) and the mature rating will be 9253 hp (6.9 MW). The program is due go to 11,400 hp (8.5 MW) and subsequently uprate to cover the power range from 8050 to 13,400 hp (6 to 10 MW).

The THM models will continue to cover the 13,400 to 20,100 hp (10 to 15 MW) power range while a scaled up version of the MGT6200 could cover the 20,100 to 26,800 hp (15 to 20 MW) range in the future.

The two-shaft machine features an 11-stage compressor, with a 15:1 pres-sure ratio, and is driven in its introducto-ry rating at 12,450 rpm by a two-stage, air-cooled, high-pressure turbine. The power shaft features a two-stage, low-pressure turbine with a 5400 to 12,600 rpm operating range. In the single-shaft configuration the turbine section fea-tures three stages, with the first two air-cooled. The generator is coupled on the cold end side to allow an axial exhaust duct to the stack or to the HRSG.

The combustion system features six cans fitted with dry low-emissions burn-ers to minimize NOx and CO emissions. Tests on the prototype running on natu-ral gas have highlighted single-digit fig-ures but the official figure guaranteed by MDT is 15 vppm NOx at 15% O2. This combustion system has been de-signed from the very beginning as DLN for natural gas-fueled units. A water-injected system for liquid fuels will be implemented later.

The machine is built in modules for easy assembly and maintenance.

The auxiliary gearbox carrying the electric starter motor and the main lube oil pump serves also as front support for the entire gas turbine. The turbine air-intake casing, rested on the auxiliary gearbox, contains the first journal bearing and the double-acting axial thrust bearing, both of the tilting pad type. Both bearings are easily accessible without need to open the horizontally split casing.

The shaft, of the drum type, fea-tures a front hub section followed by three rotor discs and a rear hub.

Hirth serrations ensure correct axial positioning of the rotor components once the central tie rod is tightened and also absorbs the torque transmit-ted by the HP turbine. The 11 blade rows of the axial compressor are mounted on the rotor drums. The sta-tor vanes are mounted on the vane carrier, the inlet guide vanes and the first three rows of stationary vanes are of the variable geometry type.

A high-accuracy electric servo mo-tor, connected to the turbine digital control system, actuates the four vari-able geometry rows from the com-pletely closed position at start up, until 75% of speed to the fully open posi-tion at 100% of speed and full load.

The discs of the two-stage power

n The twin-shaft turbines were installed at this SolVin combined heat and power plant at Rheinberg, Germany.

OCTOBER 2013 18 COmpREssORtech2

CT273.indd 2 9/23/13 10:24 AM

OCTOBER 2013 19 COmpREssORtech2

along the air and hot gas path to en-sure quick inspection and reduced maintenance time.

Future developmentsWhile the single-shaft version the

MGT6100 is now available for sale at the 8314 hp (6.2 MW) introducto-ry rating, MAN is progressing in the development of the 11,400 hp (8.5 MW) version, in both the single- and two-shaft configuration.

The upgraded version will feature a more sophisticated air-cooling system of the first two turbine stages, which will allow maintaining the turbine inlet temperature beyond 2192°F (1200°C) while running on natural gas.

The THM line of gas turbines fea-turing new combustion chambers will continue to be used specially for dif-ficult gas applications as syngas, bio-gas, etc. In fact, these turbines feature only two combustors and their larger dimensions together with a lower turbine inlet temperature of 1868°F (1020°C), facilitate the exhaust emis-sions control. CT2

(918) 283-9200 Fax (918) 283-9229 www.axh.com

286,000 SF Manufacturing Facilities on 38 Acres

Experience, Reliability, Integrity...

AXH.indd 1 4/16/12 4:42 PM

turbine are mounted on the rear hub before the second journal bearing.

The unshrouded first stage and the shrouded and interlocked second stage turbine blades are anchored to the discs by fir-tree roots. Both discs and blades are cooled by a stream of air from the axial compressor diffuser.

The intermediate turbine casing as well as hosting the compressor diffuser serves as support to the six combustion chambers, the hot gas transition ducts and the two nozzle guide vane carriers.

At the end of the intermediate cas-ing, six struts support the rear bearing casing and serve as lube oil ducts for bearing lubrication.

The combustion chambers, posi-tioned with 35° inclination relative to the centerline, feature a vortex stabi-lized burner section, a large volume for combustion, and supply, through the transition ducts, hot gases at uniform temperature to the first tur-bine nozzles. Both combustion tube sleeves and transition ducts are im-pingement cooled with air from the compressor outlet.

At start up and low load the burn-ers operate in the diffusion mode and shift automatically to the premix mode as soon as the turbine picks up load to ensure minimum production of NOx and CO.

The two-stage power turbine has been optimized for a high efficiency within a wide speed range. It can op-erate between 45 and 105% of nomi-nal speed (12,000 rpm).

The two discs of the low-pressure

n The single-shaft prototype MGT6100 is presently undergoing the final test program on the Oberhausen test stand. This configuration is mainly used for power generation applications.

turbine are bolted, with Hirth serra-tions, at the inner end of the power shaft in an overhung position. The shaft is supported by two tilting pad journal bearings, the rear one be-ing combined with a pivot shoe-type thrust bearing. The bearing casing is placed in the center of the low- pressure turbine casing.

Borescope access is provided all

CT273.indd 3 9/23/13 10:24 AM

Zahroof Valves Inc. (ZVI) has developed the Zahroof perfor-mance valve (ZPV), which de-

livers a noticeable change in valve performance, serviceability and re - liability, said Zahroof Mohamed, president and CEO of the Houston-based company.

“Improvements in valve design have plateaued over the past 50 years with the major improvements being made in materials and manufacturing,” Mo-hamed said. “Valves have to be ser-viced periodically due to wear of the seat and guard and the failure of the helical coil springs and the plastic sealing element(s).

“These are all due to operating con-ditions such as speed, pressure dif-ferential, molecular weight of gas and temperature. The operating conditions determine the number of impacts per minute and the severity of the im-pacts. The temperature determines the strength of the material, especially plastic. Foreign particles compound the problem.”

According to Mohamed, servic-ing requires the replacement of the springs and sealing elements and the precision machining of the metal seats and guards using special tools. Presence of solids and liquids in the gas stream, as in shale gas produc-tion, accelerate failure by several magnitudes, with valves requiring ser-vicing every five days in some cases.

The Zahroof performance valve is a drop-in replacement for existing valves in industrial reciprocating com-pressors. The current ZPV design can be applied at speeds from 350 rpm to greater than 3600 rpm, a continuous discharge temperature greater than 550°F (288°C) and a differential pres-sure greater than 2250 psi (155 bar). According to Mohamed, it is suitable for noncorrosive gases including natu-ral gas, air, CO2, H2 and N2, as well as corrosive gases such as natural gas with high H2S, acid gas, NH3 and Cl2. ZPVs contain no helical coil springs, no impact or wear on seat or carrier and no moving plastic components, Mohamed said.

“The ZPV design utilizes inter-changeable modules which are held stationary between the valve seat and carrier,” Mohamed said. “The wear in

the valve is contained in the modules. There is no impact or rubbing on the valve seat or carrier. Replacing the modules, which can be done in the field in a matter of minutes by relative-ly unskilled labor, is all that is needed to return the ZPV to factory condition. You never need to machine/replace the valve seat or carrier under normal conditions.”

Each ZPV is a reed valve, designed to allow a straight flow path through the valve. Mohamed said the flow through one module is independent of the flow through its adjacent module.

“In conventional valves, such as plate, poppet or ring valves, the flow makes at least two right angles while traversing the valve resulting in sig-nificant losses,” Mohamed said. “Ad-ditionally, the flow past a poppet or

n Here is the exploded view of an 8 in. (203.2 mm) diameter Zahroof performance valve, Type 1.

OCTOBER 2013 20 COmpREssORtech2

New Valve Design Targets RecipsDrop-in replacement for existingvalves in reciprocating compressorsBY BRENT HAIgHT

n Left: Here are three different sizes of ZPVs, with a view of the seat side of the valves. Middle: This is the exploded view of a ZPV. Right: The ZPVs feature three different sizes, with this photo showing the carrier side of the valves.

continued on page 22

CT269.indd 1 9/24/13 9:51 AM

Polysilicon Biogas HDS Gas Recovery

NEA compressors contribute significantly to the reduction of emissions in processes for the chemicals, petrochemicals and gas industries.

And even more. They are market leader for the emission-free compression and feeding of biogas into the grid.

to care for a green future with low emissions

NEUMAN & ESSER GROUP■ www.neuman-esser.com

NeumanEsser.indd 1 9/17/13 9:32 AM

ring interferes with the flow past the adjacent poppet or ring, causing large losses.

“In a ported plate valve, the flow through a port in the plate interferes with the flow through an adjacent port in the plate causing losses. Un-like a conventional valve, the straight through flow in a ZPV allows only negligible deviation of the gas stream resulting in significantly lower losses.”

Nine standard module designs are available, covering 90% of the exist-ing reciprocating compressor applica-tions in the market today.

Mohamed said each module is of the same external dimensions. A module is selected for a valve based on the operating conditions of the cyl-inder in which it is installed.

“Modules are interchangeable be-tween valves irrespective of the size of the valve, whether it be 1.5 in. (38.1 mm) in diameter or greater than 14 in.

(356 mm) in diameter, whether it is a suction valve or a discharge valve, whether the valve goes into a cylinder made by manufacturer X or a cylin-der made by manufacturer Y,” he said. “The modules can be used over a wid-er range of operating conditions than a conventional valve. You don’t have to buy a new valve when conditions change. You buy a new set of modules rather than a new set of valves.”

The inventory of spare modules that are currently held by an end user can be reduced by more than 80% when the ZPV valves are deployed. Instead of racks of fully assembled spare valves, the end user has to stock a maximum of nine module boxes. The standard modules are small and light enough to be shipped by next day air to most places in North America.

“There is a minimum height of 1.5 in. (38.1 mm), which is okay for 90% of the industry we are concentrating on,”

Mohamed said. “The other 10% of the marketplace utilizes a thinner valve design. Modifications to allow for the ZPV valves in these applications are extremely simple. Only the chairs in the cylinder need to be trimmed down to allow enough space in the cylinder for our valves to operate effectively.

“The ZPV design utilizes only stain-less steel for its seat and carrier with plastic modules containing stainless steel reeds. The petal guard has been designed … to work with oil-lubricated compressors also. The highest impact is on the petal guard and the petal guard has been specifically designed to reduce and absorb the impact force of the reeds.”

Mohamed cites field testing at a major compressor OEM R&D facility in natural gas and CO2, over a wide range of operating conditions, as vali-dation of the ZPV design.

“The power consumed by the ZPV

n Left: This is an assembled module. Right: This is a cutaway of the module through a gas flow path. In the middle is a cut section of a ZPV showing the flow path of gas through the modules in the valve.

OCTOBER 2013 22 COmpREssORtech2

n Left: Here is the flow path of gas through a conventional valve (plate/ring/poppet), showing the gas taking two sharp turns while traversing the valve. Middle: Here is a typical PV diagram of a compressor cylinder with the losses due to the traversal of gas through the valves shown in red — 20% of the power in pipeline applications is lost in the valves. Right: The flow path of gas through a ZPV showing a straight-through flow with no deviation is displayed.

n This chart shows the value proposi-tion of the ZPV in a pipeline transmission application. It reveals a 10% fuel savings (US$46,000 in annual savings) along with 10% reduction in emissions or US$30 mil-lion additional throughput through the same compressor with no change other than the installation of ZPVs.

CT269.indd 2 9/24/13 3:45 PM

n This chart shows measured data at a working compressor station, revealing the comparisons be-tween a ZPV and Poppet valve.

ranged from 4 to 8% less than that consumed by the standard valves,” he said. “The ZPV was also field tested in two different working compressor sta-tions. The power reduction was mea-sured by the company reliability group to be 10% less than the most efficient conventional valve. The ZPV was sub-jected to a torture test at 3600 rpm, 450°F (232°C) discharge temperature and 9.5 pressure ratio for 3.5 months and negligible wear was observed. In the market of interest, the highest in-dustrial compressor speed is 1800 rpm and the highest discharge temperature is typically less than 350°F (176°C).

“The straight through flow path deliv-ers a minimum 10% compressor power savings in pipeline transmission (1000 rpm), which translates to US$46,000/yr in energy savings per compressor, or enables a single compressor to pump an additional US$30 million of gas through a pipeline annually (based on US$2.50/Mscf), with no change other than the valves. The proven reed design improves reliability with mainte-nance intervals increased by 2x. The reed design combined with the straight flow path makes the ZPV very tolerant to liquids and solids in the gas stream, making the ZPV ideally suited to shale gas applications, or enabling compres-sor OEMs to design smaller, higher speed compressors.

“Measured field data on a natural gas pipeline compressor running at 1000 rpm showed a 10% reduction in operating power for the same work with a corresponding 10% reduction in emissions with just a change in valves. On the other hand, it is possible to in-crease the flow through the compres-sor by a similar amount at the same

power. The improvement in power and reliability improves with speed and with an increase in molecular weight of the gas (improvements will be more notice-able in CO2, NH3 and other high MW gas applications).

“As a result of these proven and measured improvements Zahroof Valves guarantees a 20% improve-ment in valve efficiency and a 25% increase in service interval with a one year manufacturer’s warranty on the valve seat and carrier,” he said. CT2

Stockinglocations inthe U.S. &Canada

SERVICESCustomized Lubricant Application Selection

Oil Analysis • Lab and Problem Application SupportNew Product Development

QUALITY LUBRICANTS YOU CAN DEPEND ON.

PRODUCTSSemi Synthetics • Synthetic Polyalkylene Glycols (PAG’s)

Synthetic Polyol Esters (POE’s) • Synthetic DiestersSynthetic Polyalphaolefin (PAO’s)

866.366.5699 • Fax: 281.367.5685 • Synthosol.commpe@mastersprocess.com

MasterSynthetics.indd 1 1/15/13 10:02 AM

OCTOBER 2013 23 COmpREssORtech2

CT269.indd 3 9/24/13 3:50 PM

André Eijk has been a senior vibration engineer for the Flow and Structural Dynamics department of TNO since 1979. He has a bachelor’s in mechanical engineering and is a member of the API 618 (reciprocating compressors) and API 674 (reciprocat-ing pumps) task forces, ISO 13707 and chairman of the work-ing group for the new ISO 10816-8. Contact him at: andre.eijk@tno.nl. Sven Lentzen is a scientist at TNO Sound and Vibrations. He has bachelor’s in mechanical engineering and a master’s in aerospace engineering from RWTH Aachen University, and a PhD in mechanical engineering. He is a member of the Eu-ropean standardization committee for building acoustics. Con-tact him at: sven.lentzen@tno.nl. Flavio Galanti is with the Civil Engineering and Thermodynamics department of the European Patent Office. He has a master’s in civil engineering and a PhD from Delft University of Technology. Bruno Zuada Coelho is a re-searcher in the TNO Flow and Structural Dynamics department. He has a bachelor’s in civil engineering and a master’s in struc-tural engineering from the University of Porto, and a PhD from Delft. Contact him at: bruno.zuadacoelho@tno.nl.

Compressor Foundation Analysis Tool >

Reciprocating compressors generally are supported on a heavy concrete foundation. The design of such a foundation is carried out by a civil engineer, fol-

lowing the calculations of the dynamic loads generated by the compressor and driver.

In spite of the large inertia and stiffness of the foundation, problems can occur due to interaction between the me-chanical installation and the foundation. Two types of prob-lems may occur. In the first type, the interaction is such that excessive vibration levels occur in the entire concrete struc-ture including frame, cylinders, dampers and piping which can lead to alignment problems and unallowable crankcase deformations. In the second type, failure of the connections between compressor and foundation may occur due to poor

design. These problems often have been identified after the construction of the plant.

Foundations for reciprocating compressors are different than for rotating compressors (high speed, small rotating unbalance) and it appears that the design of foundations for reciprocating compressors has been performed at a poor level the last 20 years.

The new generation of designers exhibit limited experi-ence in the dynamic design of foundations, especially for reciprocating compressors. In most of the designs the soil/structure interaction is not included, even though it can have a large effect on the dynamic design. It is also known that when existing foundations are used for new larger com-pressors without adjusting the foundation, it has regularly led to vibration problems.

In a paper1 published during the EFRC conference in Ant-werp, Belgium, it was shown that placing a new compressor on an existing foundation has led to an overloading of the foundation. This was caused by the fact that not all relevant dynamic parameters were included in the calculations of the existing foundation for the new compressor.

To solve this problem a rigorous, expensive and time-consuming modification of the concrete foundation was necessary to decrease the dynamic loads on the system (Figure 1). These kinds of problems should be avoided in a very early stage of the project.

The design of foundations of reciprocating compressors becomes more and more important due to:

• Operation at higher speeds, leading to higher unbal-anced loads.

• More compressors operating at larger speed ranges, higher change on excitation of natural frequencies.

• More compressors operating at variable process condi-tions, e.g. compressors used for underground gas stor-age systems have more fluctuating dynamic loads.

• More compressors running at higher power leading to higher unbalanced loads.

• Hyper compressor installations which require special attention due to the rather high unbalanced loads.

For these reasons, the research group of the EFRC

TECHcorner

Cofanto can analyze preliminary foundation designs for recips

By AndRé EIjk, SvEn LEnTzEn,

FlaviO Galanti and BrunO COelHO

Editor’s Note: This article was taken from a paper the authors delivered at the European Forum of Reciprocat-ing Compressors (EFRC) held at Düsseldorf, Germany, Sept. 27-28, 2012. The authors would like to thank the R&D sponsors of the EFRC for permission to publish the results of this project.

OCTOBER 2013 24 COmpREssORtech2

continued on page 26

CT263.indd 1 9/23/13 10:36 aM

IT’S BEEN RAISED AGAIN. Introducing the CPU-95EVS ignition system. Incorporating Altronic’s revolutionary, patented, VariSparkTM technology, the new CPU-95EVS delivers extraordinary combustion assurance on applications where the ignition system is being pushed to its limit, including lean-burn engines, applications running on bio-gas, and where poor in-cylinder air/fuel charge mixing is the norm.

Currently using our CPU-95? No problem. The CPU-95EVS is a drop-in replacement for your existing CPU-95 and uses the same Display Module, primary harness, ignition coils, and wiring. It even mounts in the same place.

HOERBIGER Engine SolutionsFind a distributor near you at www.altronic-llc.com

Altronic_Oct13_WW.indd 1 8/7/13 3:32 PM

OCTOBER 2013 26 COmpREssORtech2

initiated a project to develop a compressor foundation analysis tool program, named Cofanto. This program is de-signed to provide a simple and easy to use tool to check the preliminary or existing design of a reciprocating compres-sor foundation with respect to dynamic loads in an early stage of the project. This tool should enable the plant com-missioner to perform a check without repeating the detailed analyses carried out already by the design engineers.

n Figure 1. This shows the modification of the foundation.

Foundation analysis toolCofantro is a program for carrying out a simplified dynam-

ic response analysis of a compressor and its foundation. The program serves as a tool to check whether the design of a compressor foundation is susceptible to excessive vi-brations during operation of the compressor.

The tool is recommended for use by those who intend to install a compressor and who want to verify whether the combination of selected compressor and foundation is feasible. It is used to predict the vibration levels in-dicatively and by no means is it intended for the actual design of foundations nor as a substitute for the required engineering calculations.

Basic machine configurations can be selected in com-bination with either a mat foundation or pile founda-tion. The machine can consist of a separate driver and compressor, both of which are connected to the same foundation block. Loads are specified for each operat-ing speed either in terms of a time history over a single cycle or as amplitudes for each harmonic of the operating speeds. The program calculates the vibration response of the compressor, driver and foundation in terms of dis-placement, velocity and accelerations for each specified load case.

The program generates graphs of the time history of the response as well as a summary containing the maximum, minimum, peak-peak, mean and root mean square (RMS) values. These values can be compared with recommended threshold values, e.g. EFRC Guidelines for Vibrations in Re-ciprocating Compressor Systems2.

The tool is assembled from existing soil/ground interac-

tion software and models that TNO developed in earlier projects on the dynamics of soil. In these projects the dy-namics of soil has been based on Wolf’s3 theory and has been proved to be a good approach.

The tool has been developed for both slab type foun-dations and foundations mounted on piles, including soil structure interaction effects and dynamic impedance func-tions describing a frequency dependent soil/foundation re-sponse. Simple mass-damper-spring-dashpot systems can be included to describe various parts or modes of vibration of the foundation/compressor system.

The final result of the check is that one of the following flags is assigned to the foundation: correct, marginal or wrong. If the design is marginal or wrong, it is advisable to carry out detailed calculations to check the design into more detail.

Theory of underlying modelSpring-mass-damper model — The underlying model is

based on multiple spring-mass-damper systems (Figure 2).

n Figure 2. Drawing depicts the basic model of machine and foundation.

Each node in the model exhibits six degrees of freedom, namely three translations and three rotations. Therefore, for the machine and the driver, a mass matrix is assumed con-taining the mass in the three translational directions and the moment of inertia computed for each rotational direction.

As the machine and the driver are not necessarily posi-tioned at the center of mass (COM) of the block or the mat (depending on whether a block is present), a rigid link be-tween the contact point and the COM of the block or the mat is introduced. Therefore, an additional node is introduced at the contact point. The rigid links translate the translation and rotation of the COM of the block or mat into a motion of the contact point.

It is further possible to model anti-vibration mounts (AVM’s) between the machine and block or mat and be-tween the driver and block or mat. The anti-vibration mounts can be modeled as translational and rotational springs and

continued on page 28

CT263.indd 2 9/23/13 10:42 AM

www.ccsia.com HEADQUARTERS: 11275 Aurora Ave., Des Moines, IA 50322, USA +1 515.278.9655

TURBO MACHINERY CONTROL APPLICATIONS

SURGE PREVENTION CONTROLLER

COLD RECYCLE CONTROLLER

STATION CONTROLLER

GAS TURBINE CONTROLLER

STEAM TURBINE CONTROLLER

POWER UTILITY CONTROLLER

PROCESS CONTROLLER

EXTRACTION CONTROLLER

VALVE MANAGEMENT CONTROLLER

For direct questions and project inquiries, please E-mail sales@ccsia.com.

CONTINUOUS CONTROL SOLUTIONS (CCS) provides the next generation of control

technology and solutions inclusive of

design, implementation and commissioning

of reliable, high-quality control systems

for industrial TURBO MACHINERY control

applications.

Our systems are flexible, transparent and

robust, focusing on our customers’ entire

processes, rather than simply protecting

machines, providing a true and proven

continuous control engineering solution

tailored individually to each project.

SURGE PREVENTION CONTROLLER (SPC) CCS’s patented SPC protects your centrifugal or axial compressor from damages, costly repairs and production losses induced by surging. The SPC allows you to define the surge line under variable conditions giving you optimum surge protection without unnecessary recycling or blow-off.

CCS’s patented SPC provides two independent control loops based on flow (dP) and pressure ratio (Rc), unlike anyone else in the market. If at any point in the process either measurement becomes unavailable, CCS provides true continuous control by automatically selecting the available control loop. The controller provides fully-integrated, multi-loop, multiple-body compressor surge control on any IEC61131-compliant hardware platform, eliminating the need for a costly “black-box” solution.

THE NEXT GENERATION OF TURBO MACHINERY CONTROL

ContinuousControl.indd 1 2/18/13 11:25 AM

OCTOBER 2013 28 COmpREssORtech2

viscous dampers. The viscous dampers are assumed to be hysteretic, which makes it possible to model a constant damping factor in the whole frequency domain of interest.

The block can be isolated from the mat by springs and dampers as well. It is also possible to replace the block (and possibly the isolation) by a table top. The table top consists of a rigid mass including moments of inertia. The legs of the table top are summarized into one spring stiff-ness and damping ratio for the translations and rotations of all three directions.

Finally, the machine and driver (and possibly including block or table top) are supported by the mat. The mat is mod-eled as a rigid mass with the appropriate moments of inertia.

The foundation — The mat serves as a foundation for the machine and it is supported by the soil and in certain cases also by piles. The system soil/piles can be replaced by a single spring-damper system for the translation and rotation in all three directions.

Alternatively, the point compliance transfer function (for all translations and rotations) of the soil with piles can be determined according to the models described by Wolf3. Since the Wolf model delivers the dynamic behavior in the frequency domain, the total simulation is performed in the frequency domain, where the spring-mass-damper system, discussed previously, is connected to the Wolf model in series. In the following, the principle of the Wolf model is explained. For further information on the model, see reference 3.

The Wolf model is based on the assumption that the me-chanical behavior of a disk, of any shape, on a half-space (Fig-ure 3) can be modeled by a circular disk on an infinite cone as shown in Figure 4. A discussion on the foundations of this assumption can be found in references 5 and 6.

n Figure 3. This drawing shows an excited disk on a half-space generating compressive (P), shear (S) and Rayleigh (R) waves.

The opening angle and the cut of the cone can be deter-mined depending on the disk geometry and the soil charac-teristics. The determination is performed such that the wave behavior in the cone-model represents the wave behavior in the half-space, taking into consideration for instance the reflections on the boundaries of the layers.

n Figure 4. This infinite cone model describes the mechanical behavior of a half-space.

It is therefore possible to replace a layered half-space with a cone model. The advantage of using a cone model can be found in the simplified analytical solution based on a one-dimensional rod theory. In order to model piles in a half-space it is important to initially consider a disk enclosed in the half-space (Figure 5).

n Figure 5. This excited disk is enclosed by a half-space.

The excited disk generates waves that are reflected from the free surface. It is therefore important to replace the half-space with a double-cone model to incorporate the reflec-tions as shown in Figure 6.

n Figure 6. This infinite double-cone model describes the me-chanical behavior of an excited disk embedded in a half-space.

continued on page 30

CT263.indd 3 9/23/13 10:42 AM

MACHINERY ANALYS IS

Keeping it running smoothly since 1967BETAMACHINERY.COMSee us at the GMC, booth 215

BETA.indd 1 9/18/13 11:16 AM

OCTOBER 2013 30 COmpREssORtech2

As the embedded disk is assumed to be infinitesimally thin, an embedded pile or rod can be modeled by con-necting a series of embedded disks. To analyze the dy-namic behavior of a group of piles with their heads con-nected by a rigid cap (the mat) and with vertical axes, the interaction of the individual piles via the soil has to be taken into consideration.

It is, for instance, incorrect to add the dynamic stiffnesses of the individual piles in order to obtain the dynamic stiff-ness of the pile group. While forcing one pile down, other piles will follow. Therefore, while forcing all piles simultane-ously, the pile displacement is larger than predicted when simply adding the stiffnesses.

References 7 and 8 discuss the pile-soil-pile interaction, which is strongly frequency dependent and can be accu-rately incorporated into the cone model concept by incorpo-rating so-called dynamic-interaction factors. These interac-tion factors are always determined between two piles. While the source pile (s) is dynamically excited, the response of both piles is determined using wave analysis, and the ratio between the response of the receiver pile (r) and the source pile describes the interaction factors.

n Figure 7. Cylindrical waves are emitted from the source pile and propagating towards the receiver (left: vertical waves; right: horizontal waves).

In Figure 7, the source and the receiver pile are shown from above. The source pile emits shear and compressive waves that interact with the receiver pile. For the vertical movements only shear waves are responsible for the pile interaction. The interaction factor does not depend on the relative angle be-tween the piles, but rather on the distance between them.

On the right side of Figure 7, the waves responsible for the horizontal interaction are shown. Considering the left-right motion (relative to the illustration), the compressive waves are responsible for the interaction when the relative location of the receiver pile is in the direction of the motion. When the relative position of the receiver pile is perpendicu-lar to the motion, then the shear waves are responsible for the interaction. For the horizontal coupling, thus, the rela-tive angle between the receiver and the source pile is an influencing factor.

When all interaction factors between all the possible combinations of pile pairs are computed, and when the dynamic-stiffness coefficients of the single piles are known, the dynamic-stiffness matrix for harmonic loading of the pile

group can be determined using the standard matrix formu-lation of structural analysis.

The test case consists of four different layers of soil com-bined with a compressor mounted on a concrete slab with pile foundation. The finite element model is shown in Figure 8.

n Figure 8. This shows a finite element model.

Figure 9 presents the comparison between the results of the horizontal compliance for the two models. It can be concluded that a good agreement is found for both models in all directions. The peak occurs at a similar frequency with a similar response. The static response (as the frequency tends towards zero) is also in agreement.

n Figure 9. The comparison of horizontal compliance between the Wolf and FEM models is given.

Program structure — The core of the program is de-veloped in MATLAB and a graphical user interface (GUI) is developed specially to control the core. The GUI has the following main functions: geometry input, loads definition, calculation control and output. In the following subchapters, each of the main functions is described in detail.

Model input — The available components to build the model are grouped as follows (Figure 10):

• Machine: compressor and driver.• Interface: rigid or flexible.• Support: none, block, block on flexible elements and

tabletop.continued on page 32

CT263.indd 4 9/23/13 10:43 AM

www.cookcompression.com

See What’s Happening at Cook Now

These�are�just�a�few�of�the�installations�where�Cook�valves�are

reaching�run�times�once�thought�impossible. It’s�the result�of

custom�engineering, patented�designs�and�advanced�

materials�only�available�from�Cook�Compression. For�any

heavy-duty�compressor, in�any�type�of�service,�anywhere�in

the�world�—�Cook�makes�extended�valve�life�a�reality.

MOPPET® cartridge-design seriesRugged & field repairable

Manley® radiused-disc seriesIdeal for demanding applications

Optima™custom-plate seriesOptimized for superior performance

US Gulf CoastGas Gathering100% Increase

ColombiaGas Gathering 300% Increase

OmanGas Gathering 495% Increase

ChinaCNG Fueling 300% Increase

RussiaAmmonia Gas 600% Increase

AustraliaGas Production 100% Increase

ThailandPolypropylene Gas 200% Increase

CongoGas Gathering 150% Increase

CanadaCarbon Dioxide 200% Increase

EnglandBoil-off Gas750% Increase

Achieving The Impossible Worldwide.Right now Cook compressor valves are setting

new run time records around the globe.

CCO_2013 Valve Ad Layouts_Layout 1 8/20/13 3:20 PM Page 3

Cook.indd 1 8/20/13 4:03 PM

OCTOBER 2013 32 COmpREssORtech2

• Foundation: pile or mat.The input parameters for each of the different compo-

nents are:

n Figure 10. These are the available components for foundations.

Machine:• Total mass.• Mass moments of inertia in three directions.• Position in the X, Y and Z direction. Interface:• Translation and rotation spring stiffness in three directions.• Damping ratio.Block support:• Position in the X, Y and Z direction.• Density.• Mass moments of inertia in three directions.Tabletop support:• Young’s modulus.• Width of columns.• Cross-section area.• Number of columns.• Column length.• Damping ratio.Mat:• Dimensions.• Density.Springs:

• Translation and rotation spring stiffness in three directions.• Damping ratio.Piles:• Young’s modulus.• Cross section diameter.• Length.• Density.• Number of piles.• Position three directions.Soil:• Number of layers.• Shear modulus.• Density.• Poisson’s ratio.• Damping ratio.• Thickness.

n Figure 11. An example of a Cofanto model is shown.

Load input — A number of load cases can be con-sidered that can be specified either in the frequency or in the time domain. Loads can be specified acting from the compressor as well as from the driver. In both cases the loads are assumed to act in the center of mass of the respective component. Other loads, e.g. pulsation-induced forces, can also be considered but in that case these loads should be “converted” to act in the COM of the compressor or driver.

Results output — The results will be presented both in tabular and graphical form. The generated text file will contain the results of the vibration displacement, vibra-tion velocity and vibration acceleration levels in maxi-mum, minimum, mean, peak-to-peak and RMS values. The RMS values will be compared with a specified crite-rion, e.g. “EFRC Guidelines for Vibrations in Reciprocat-ing Compressor Systems”2.

Further on, the results file will contain the reaction loads on the support block if present. Otherwise these are the loads applied on the mat. In the final part of the analysis, the user has the opportunity to inspect the re-sponse in a graphical way. Graphs are available with me-chanical natural frequencies, time wave form of the input

continued on page 34

CT263.indd 5 9/23/13 10:43 AM

Leading the way in …

stationary engine emissions

ParaLLeL FLow Based on its more than 60 years of catalytic converter

manufacturing expertise, Catalytic Combustion offers

best-in-class Parallel Flow housings.

Our hinged “Quick Cover” designs afford fast

and easy access to catalysts, saving time

and money during in-the-field service.

Features and BeneFits

FEATURE BENEFIT_________________________________________________________________________________________________________________________________________________ Carbon or stainless steel construction Industry’s longest lasting housings, built to customers’ specifications_________________________________________________________________________________________________________________________________________________ 12 possible combinations of rectangle catalyst configurations Improved emission control using three rectangular catalysts in strategic placements_________________________________________________________________________________________________________________________________________________ DBG Sealing Technology Innovative Double Bulb Gasket provides the best seal for removal and bypass prevention_________________________________________________________________________________________________________________________________________________ All installation hardware included Fastest installation on the market for parallel flow application_________________________________________________________________________________________________________________________________________________ Hinged “Quick Cover” catalyst access panel Easiest catalyst element change_________________________________________________________________________________________________________________________________________________ Two lifting eyes pre-installed No field assembly or modification required _________________________________________________________________________________________________________________________________________________ Catalytic Combustion manufacturer’s “Quality 4” plate Validates date of manufacture and quality assurance with full tracking capabilities_________________________________________________________________________________________________________________________________________________ Catalytic Quality Craftsmanship Guarantee Industry-leading 12-month craftsmanship warranty _________________________________________________________________________________________________________________________________________________

BLOOMER, WI 715-568-2882GILLETTE, WY 715-933-2641FORT WORTH, TX 715-933-1559TULSA, OK 715-933-4154

www.CatalyticCombustion.com

Catalytic.indd 1 8/19/13 10:27 AM

OCTOBER 2013 34 COmpREssORtech2

Discussion of results — The compliance transfer func-tion on the block in the rod direction is shown in Figure 14. From this figure it can be concluded that a mechanical natu-ral frequency does not coincide with the frequency of the excitation loads of one (8.25 Hz) and two (16.5 Hz) times the compressor speed.

A picture with the maximum calculated peak-to-peak vibration displacement of the block is shown in Figure 15. The maximum calculated vibration displacement of 0.035 mm peak-to-peak is in the rod direction and is caused by the unbalanced moment in the horizontal plane (moment around the vertical axis) of one times the compressor speed. This value is within the A/B evalua-tion zone of the EFRC guidelines.

This means that as a result of the Cofanto calcula-tions, the foundation should be flagged “correct,” which is also according to the field experience because no problems have been encountered.

n Figure 14. This graph depicts the compliance transfer function of the foundation block in Z direction (4-TZ).

loads, reaction loads, vibration displacement, vibration velocity and vibration acceleration levels (Figure 12).

n Figure 12. This graph shows a loads time waveform.

Validation modelsTo check the results of the program, two test cases were

conducted. For both test cases, vibration measurements were carried out in the field for both test cases on a reciprocating compressor system.

Test case one• System Description:• Three-stage compressor with three cylinders and one

dummy.• E-motor drive: 2759 kW.• Fixed speed of 495 rpm (8.25 Hz).• Compressor and driver mounted on a block.• Block mounted on mat.• Mat mounted on concrete piles.• Input forces: compressor unbalanced forces of one and

two times compressor speed.continued on page 36

The Cofanto model is shown in Figure 13.

n Figure 13. The final Cofanto model is shown (Red: ma-chine; blue: driver; magenta: block; yellow: mat; grey: piles; brown: soil layer surfaces).

CT263.indd 6 9/23/13 10:44 AM

Find out more by visiting: www.fwmurphy.com/ad/oil-level-puzzle_ct2or call USA: +1-918-317-2643

LM500 Series LM300 Series L129 Series

131

1295

8

-201

3

DO YOU HAVE ALL THE RIGHT PIECES TO COMPLETE YOUR PUZZLE?Rotating equipment needs lubrication. Don’t let oil supply problems leave your equipment unprotected.The new LM500 maintains oil level and signals your control panel when supply issues arise saving you costly downtime.

• Test pushbutton confirms float and switch are operating correctly

• Maintains the crankcase oil level of an engine, compressor, or pump

• Large ‘frog-eye’ lens for easy visual inspection of oil level

• CSA* & ATEX certification options

*CSA certification for selected LM300 models.

Complete your instrumentation puzzle with Murphy’s family of

Oil Level Controllers.

Visit us at Booth #718

Murphy_Level.indd 1 9/17/13 10:07 AM

The results of the measurements for this location are shown in Figure 16. The measured vibration displacement is 0.05 mm peak-to-peak (pp). This picture also shows high-er frequency components that are probably caused by the pulsation-induced pulsation forces acting on the pulsation dampers and on the cylinder passage volumes.

This means that the vibration displacement caused by only the unbalanced mechanical loads will be lower than measured. The ratio of the measured and calculated value at this location is 1.43 and will even be lower when the ef-fect of the pulsation-induced forces are taken into account.

For dynamic calculation of foundations where the soil/foundation interaction can have an important effect, the re-sults between measurements and calculations show a good agreement with this check tool.

General conclusions are:• Results of calculations and measurements are in good

agreement;

• Pulsation-induced forces can have an important effect on the vibrations of the foundation and should be included;

• Another test case has shown similar results.

ConclusionsDue to higher excitation loads, more variable process

conditions, large range in variable speeds, the dynamic loads on the reciprocating compressor foundations become more challenging. Together with the fact that field experi-ences have shown that there is a lack of knowledge in the dynamic design of foundations, this has led to more failures of foundations and compressor components.

All dynamic loads must be considered in the dynamic de-sign of a compressor system. Modification of an incorrect designed foundation is not so easy and can be very ex-pensive and time-consuming. For that reason the research group of the EFRC decided to develop an easy to use tool which can be used to check the preliminary dynamic design of a foundation in a very early stage of the project.

This check tool, named Cofanto, enables the plant com-missioner to perform a check without repeating the detailed analyses carried out already by the design engineers. The soil/foundation interaction has an important effect on the dy-namic properties of the system and this special feature has been included in the program. Field measurements have shown that the results of Cofanto are in good agreement.

Pulsation-induced forces can have an important effect on the vibrations of the foundation and test results have shown that these forces should also be included in the dynamic design of foundations of reciprocation compressors. CT2

References1. Gast, S., Borsig, Z.M., Rainer, P.M., “Modification of

a Reciprocating Compressor Due to Process Changes in the Total Refinery in Spergau, Germany,” EFRC, June 2005, Antwerp, Belgium.

2. Eijk, A., “EFRC Guidelines for Vibrations in Reciprocat-ing Compressor Systems,” Sixth Conference of the EFRC (www.recip.org).

3. Wolf, J.P., “Foundation Vibration Analysis Using Simple Physical Models,” Prentice Hall, 1994.

4. API 686, “Recommended Practices for Machinery In-stallation and Installation Design,” First edition, April 1996.

5. Weck, J.W. and Wold, J.P., 1993, “Cone Models for Nearly Incompressible Soil,” Earthquake Engineering and Structural Dynamics, 22 (1993), pp. 649-663.

6. Weck, J.W., and Wold, J.P., 1993, “Why Cone Models Can Represent the Elastic Half-Space,” Earthquake Engi-neering and Structural Dynamics, 22 (1993), pp. 759-771.

7. Dobry, R., and Gazetas G., “Simple Method for Dy-namic Stiffness and Damping of Floating Pile Groups,” Géo-technique, 38 (1988), pp. 557-574.

8. Makris, N., and Gazetas, G. “Dynamic Pile-Soil-Pile Interaction, Part II: Lateral and Seismic Response,” Earthquake Engineering and Structural Dynamics, 21 (1992), pp. 145-162.

OCTOBER 2013 36 COmpREssORtech2

n Figure 15. The calculated vibration displacement on the foun-dation block is shown.

n Figure 16. This is the measured vibration displacement on the foundation block.

CT263.indd 7 9/23/13 10:44 AM

Bringing energy and the environment into harmony.®

75412 DR Magnetic Bearing Ad for Compressor Tech Two — Full Page, 4/C, B: 8.25”w x 10.75”h, T: 8”w x 10.5”h, L: 7.5”w x 10”h

SYNCHRONY® MAGNETIC BEARINGS—A POWERFUL FORCE IN THE WORLD OF ROTATING EQUIPMENT.Make your rotating equipment cleaner, more effi cient and more reliable with our Synchrony magnetic bearings. These best-in-class bearings can make a world of difference by improving the performance and reducing life cycle costs of your rotating equipment. Because the shaft is positioned and supported with magnetic forces and without contact, bearing losses and wear are minimized. In addition, the need for an oil lubrication system is completely eliminated. So make the switch to Synchrony magnetic bearings, and add a powerful force to your rotating equipment.

» www.dresser-rand.com» www.synchrony.comCompressors–Turbo & Recip / Steam Turbines / Gas Turbines / Engines / Control Systems / Expanders

Make your rotating equipment cleaner, more effi cient and more reliable with our Synchrony magnetic bearings. These best-in-class bearings can make a world of difference by improving

shaft

and wear are minimized. In addition, the need for an oil lubrication system is completely eliminated. So make the switch to Synchrony magnetic bearings, and add a powerful force

Salem, Virginia: (Int’l +1) 540-444-4200 / info@dresser-rand.com

Visit us at The GMRC Gas Machinery Conference, Booth 303, Albuquerque, NM, October 6-9 and ADIPEC 2013, Abu Dhabi, UAE, November 10-13

75412_DR_MagBrngAd_CTT.indd 1 9/13/13 11:08 AMDresserRand_Sync.indd 1 9/24/13 10:36 AM

Rising lube oil costs, environ-mental concerns and chang-ing process requirements

are driving demand for better-per-forming wiper packing in reciprocat-ing compressors.

Leakage rates of 0.35 fl.oz/hr (10.4 ml/hr) and higher are no longer con-sidered acceptable. Applications with strict oil-free requirements, such as compressed natural gas service, are becoming more common.

Furthermore, oil wipers — origi-nally designed simply to limit the amount of oil migrating along the rod — are often expected to provide at least some level of gas sealing ability between the crankcase and

distance piece. As a result, sealing component makers are responding with new approaches to wiper ring design and are achieving results in the field that were considered im-possible not long ago.

Effective oil wiper packing can:• Lower oil consumption and costs,• Decrease labor requirements for

monitoring and replenishing oil,• Reduce leakage, cleanup and dis-

posal costs,• Improve environmental compliance,• Avoid contamination of oil-free

processes,• Prevent oil dilution and contamination,• Increase overall compressor reli-

ability and availability.

Material advantagesConventional wiper rings are con-

structed of metallic materials, most often cast iron or bronze. They re-main the most common choice for many compressors with modest oil wiping requirements because they are relatively low in cost. Metal also simplifies manufacturing because rings can easily be fashioned with a sharp wiping edge.

However, metallic wipers have draw-backs. Metal-to-metal contact with the compressor rod can result in damage to the rod. Continual abrasion can also lead to rapid wear of wiper rings and short service life in some applications. While metallic rings are strong, they are also rigid. Therefore, in operation, metallic ring surfaces cannot conform to irregularities in the rod surface, so sealing and wiping efficiency can be compromised.

To counter these limitations, wiper rings have been manufactured us-ing thermoplastic materials such as polyether ether ketone (PEEK), which

Advanced Materials Improve Wiper Packing Performance > Ultimate goal is leak-free

compressor operationBy CRAIg MARtIn AnD

SKIP FoREMAn

Craig Martin is manager of applications engineering for Cook Compression, based in Jeffersonville, Indiana. He has a chemical engineering degree from the University of Kentucky and served as a senior engineer for Energizer Battery Inc., prior to join-ing Cook Compression in 2004. He works primarily on piston ring and rod packing products. Contact him at: cmartin@cookcompression.com. Skip Foreman is director of Americas product sales for Cook Compression, based in Stafford, Texas. He holds a degree in engineering technology from Texas A&M University. Before joining Cook Compression 2000, he was an applications engineer for Dresser-Rand. Contact him at: sforeman@cookcompression.com.

OCTOBER 2013 38 COmpREssORtech2

n Figure 1. These test results show the superiority of two nonmetallic materials, PEEK and TruTech 3110, in preventing oil leakage past wiper rings.

continued on page 40

CT272.indd 1 9/23/13 10:49 AM

for highest effi ciency

your high pressure solution

LEOBERSDORFER MASCHINENFABRIK

www.lmf.at

THE NEW DIMENSION OF PROCESS GAS COMPRESSORSTrust in solutions for highest effectiveness using LMF’s process gas compressors with pressure rates up to 700 bar (10,150 psi) for a variety of applications (eg. underground storage for CO2 / natural gas, desulpherization, fl are gas, gas injection, boil-off gas).

API 618

LMF.indd 1 9/17/13 9:37 AM

have been used in packing case seal rings for many years. These wiper rings exhibit significantly improved oil wiping over metallic rings (Figure 1).

More recently, sealing component maker Cook Compression introduced a nonmetallic material specially devel-oped for oil wiping efficiency. Called TruTech 3110, this material is a polytetrafluoroethylene-based (PTFE) compound that has strength and du-rability, as well as flexibility to tightly conform to the rod surface and elimi-nate leak paths.

Figure 1 shows relative leakage rates of different materials from tests conducted on an Ariel JGK compres-sor with a 2.875 in. (73 mm) diameter rod running at 700 rpm. These test re-sults show that a wiper ring made with TruTech 3110 removes approximately 86% more oil from the rod than the same ring design manufactured from cast iron. The TruTech 3110 ring per-formed 64% better than bronze and 11% better than PEEK, another non-metallic material.

The physical properties of TruTech 3110 (Table 1) allow rings to be manu-factured with sharp wiping edges that maintain their shape and wiping effec-tiveness over extended use. The mate-rial also imparts flexibility that enables the ring to conform to the rod surface. Al-though developed for use in wiper rings, the material has also been used effec-tively to manufacture piston rings, rider rings, rod packing rings and bushings.

As a result of the increased effec-tiveness shown by new nonmetallic

wipers, some compressor manufac-turers are beginning to offer them as standard equipment, particularly for nonlube applications.

The shape of rings to comeImprovements in materials have

given new life to long-established wiper ring styles that were previously manufactured with metallic wiping edges. Compressor operators are finding that some of these traditional designs — now equipped with nonme-tallic materials — are proving more ef-fective than others. For example, com-pressor operators are demonstrating a preference for radial-cut rings over tangent-cut rings (Figure 2).

The improvement in performance is again due to increased flexibility. Radial-cut rings conform to the rod better than tangent-cut rings. This is because under operating conditions

the sharp points of a tangent-cut ring can sometimes push themselves un-derneath the adjacent segment as thermal expansion sets in, causing a loss of contact with the rod. Con-versely, the geometry of radial-cut rings allows them to maintain contact with the entire circumference of the rod despite thermal expansion and maintain a better seal.

To a lesser extent, ease of instal-lation is another factor in favor of radial-cut rings. The sharp corners on the ends of the tangent-cut seg-ments are relatively fragile. They re-quire extra care in handling and, in rare instances, can break off during installation of the ring.

Entirely new wiper ring styles are combining with new materials to pro-duce impressive results. For example, the RTV wiper design from Cook Compression consists of a three-ring set that fits in a single groove of a packing cup.

The first ring has a proprietary knife-edge geometry that allows it to remove virtually all of the oil film when it contacts the rod. The second ring of the assembly is sideloaded. An offset spring seats the first and third rings against the adjacent cup surfaces (Figure 3).

As a result, the wiper assembly remains stationary instead of mov-ing with the rod like other wiper de-signs. This eliminates the “pumping action” that tends to force oil past the wiper packing.

All RTV ring materials are con-

n Table 1. Characteristics of the TruTech 3110 material are given.

OCTOBER 2013 40 COmpREssORtech2

n Figure 2. Radial (left) and tangent (right) rings are shown.

CT272.indd 2 9/24/13 3:53 PM

Fo

od &

Bev

erag

es

Che

mis

try

Pet

roch

emis

try

Mac

hine

Con

stru

ctio

n

R

aw M

ater

ials

E

nviro

nmen

t

Sp

ecia

l Eng

inee

ring

Mehrer Compression GmbH & Co KG · Rosenfelder Str. 35 · 72336 Balingen · GermanyPhone +49 (0)7433 2605-0 · Fax +49 (0)7433 2605-41 · www.mehrer.de · service@mehrer.de

MEHRER SERVICE

ACTIVE SERVICE AND MAINTENANCE MANAGEMENT

COMMISSIONING, MAINTENANCE AND REPAIR

Mehrer.indd 1 9/13/13 9:58 AM

structed of nonmetallic materials that prevent galling and damage to the compressor rod. The design and side-loading characteristic of RTV assem-blies also creates a highly effective gas seal between the crankcase and distance piece.

New design tested in hydrogen compressor

The effect of this three-ring-set de-sign was demonstrated at a Russian petrochemical facility. The plant was experiencing severe problems and high costs in maintaining the filtration/ separator phase of its process after compression.

The trouble stemmed from a hydro-

gen compressor that had originally been installed with lubricated cylinders and packing cases. Lube oil leaking from the compressor was contaminat-ing expensive filters, causing them to malfunction and requiring costly main-tenance. In addition, this compressor (along with a second six-cylinder hydro-gen compressor) was consuming 5812 gal. (22,000 L) of oil per year.

It was determined that the plant should convert the hydrogen compres-sor from lubricated to nonlubricated service. A design team reviewed key parameters of the application: 1450 psi (100 bar) at 221°F (105°C) on the final stage, 71% hydrogen plus 27% carbon monoxide gas mixture and high speed

n Figure 3. This is the Cook RTV wiper with side-loaded second ring.

of 16.4 fps (5 m/s). The team recom-mended a series of changes that in-cluded replacing existing wiper rings with Cook RTV wiper packing.

All recommendations were carried out on the compressor. With the new wiper packing in place, there was no detectable leakage from the crank-case. This prevented contamination of the seal rings in the pressure packing case, which is an essential require-ment for nonlube conversions.

The conversion has eliminated pro-cess contamination and excessive oil consumption associated with this com-pressor. The compressor has contin-ued to run trouble-free for more than three years.

More, better choicesThe overall impact of new designs

and materials is this: wiper packing is no longer a mechanism to sim-ply limit oil leakage, but a means of eliminating leakage altogether in many applications.

Compressor operators have entered an era with more wiper packing choices than ever before. The differences be-tween them can be substantial.

Maintenance professionals must therefore properly assess the unique needs of each compressor applica-tion, receive the technical support necessary to evaluate various wiper recommendations, and select a wiper that provides the optimal combination of performance and value. CT2

CT272.indd 3 9/24/13 4:00 PM

With increased focus on greenhouse gas (GHG) emissions, end users are

looking at ways to reduce methane gas emissions. Along with carbon dioxide, the Environmental Protection Agency categorizes methane as a major GHG that contributes to global warming.

Some loss of methane to the at-mosphere is essentially unavoidable without extreme measures. Examples include gas leakage from reciprocat-ing compressor piston rod packing, pipeline and compressor venting re-quired for maintenance or safety, and small leaks from valve stem seals.

Methane emissions associated with the use of natural gas for pneu-matic control and power also are a prime target for reduction. Historical-ly, the use of pressurized natural gas for reciprocating engine and gas tur-bine starter motors has been a com-mon practice. Whether at the well-head or on a pipeline, there is usually enough line pressure available to ex-

pand gas through the starters to get the compression equipment started. This is an effective alternative and is essential for “black start” capability or where insufficient local utility services are available.

Where sufficient electrical power is available, a pressurized air starting system provides a better environmen-tal solution when GHG is a concern. It also reduces operating costs and eliminates the potential safety risk as-sociated with venting large amounts of natural gas “within the fence” of compression facilities.

However, designing and installing a suitable air starting system can be a complex project, especially when the system is a retrofit installation. “Set-ting the air receivers and compressors tends to be simpler than routing the pipe from the air compressor building to the units in the main compressor building and revamping the on-skid piping of several different units, which can be quite a challenge,” said Les

Pullig, vice president, engineering for Gas Compression Consultants (GCC). “It requires navigating the new pipe through a busy pipe rack, utiliz-ing existing pipe supports as much as possible, and then integrating it onto the congested engine skids.”

The starting air system design be-gins with determining the pneumatic starting motor air (pressure and flow) requirements for the engines at the specific site. This is influenced by how many units must be started at once and how much time can be tolerated for the air system to pump back up to pressure after a start attempt. This requirement determines the number and size of air compressors and re-ceivers (i.e., storage tanks).

Next, air drying equipment must be sized, electrical requirements deter-mined, space needs defined, place-ment locations chosen, piping sized and routings planned, and plant control system interfacing worked out. In ad-dition to overall project management, the air system design requires civil, electrical and mechanical engineer-ing disciplines. And there is usually a need to work with various government agencies to gain necessary building and environmental permits. Even local electric utilities may get involved, de-pending on the power requirements for the air compressors. Development of installation drawings, component pro-curement and selection, and manage-ment of contractors are also important aspects of the project. Finally, start-up and commissioning must be carried out and as-built drawings completed.

A recent GCC project at Williams Midstream’s Lathrop Compressor Sta-tion near Tunkhannock, Pennsylvania, is an example of the detail that has to be considered in such a system de-sign. The existing station included four

Converting Natural Gas Starting System To Air Cuts Emissions > Gas Compressor Consultants

manages complex retrofitBy NorM SHADE

n Two 50 hp (37 kW) Sullair Model 3700-series air compressors in NEMA 4 enclosures provide starting air for two engines simultaneously.

OctOber 2013 42 cOmpressOrtech2

continued on page 44

CT267.indd 1 9/23/13 10:58 AM

Kilowatts.indd 1 9/17/13 2:11 PM

Caterpillar G3608 and three G3516 gas engines used to drive reciprocat-ing compressors.

“Not only were GHG emissions reduction and improved safety from elimination of gas venting primary reasons for the conversion to the air start system, the wet gas that was coming into Lathrop would freeze at the skid edge 150 psi (10.3 bar) regu-lator which reduced the pressure from about 700 psig (48 bar) coming into the plant,” Pullig said.

“This required adding heat tracing and insulation on all the on-skid start-ing gas lines. Marcellus gas also tends to produce a lot of salts that fouled the starter motors and reduced their per-formance and reliability.”

The operators at Lathrop wanted enough air supply to be able to crank two of the G3608 engines simultane-ously for up to two minutes. In addi-tion to supplying air for the two-minute start cycles, the receiver volume and compressor capacity were designed to restore the air system to the re-quired starting pressure level within about 12 minutes after a start cycle.

Two 50 hp (37 kW), 460V TEFC motor-driven, oil-flooded Sullair Model 3710 rotary screw air compressors in NEMA 4 electrical enclosures were selected to provide the starting air. The two compressors were arranged on a single skid built by Blackhawk

Equipment Corp. of Arvada, Colorado, with all necessary PLC controls, in-strumentation, filters, dryers, coolers and drain connections. Each screw compressor delivers 196 scfm (5.55 m3/min) at 150 psig (10.3 bar) dis-charge pressure. They operate at ap-proximately 3665 rpm, driven through a 2.06 gear ratio by electric motors that have 1.2 service factors.

The compressors supply three 2560 gal. (9691 L), 200 psig (13.8 bar) MAWP ASME coded air receivers, measuring 60 in. (1524 mm) diameter by 220 in. (5588 mm) tall, which were installed off-skid and outside the com-pressor building on a new concrete pad. All three receivers are tied into a 6 in. (152 mm) diameter header that was routed on existing pipe racks to the main compressor building. Start-ing air is stored at 175 psig (12.1 bar).

GCC provided all engineering serv-ices required to design, permit, in-stall, start up and commission the complete engine air system. The scope included specifications and procurement of air compressors, fil-ters, dryers, receivers, instrumenta-tion and controls. The company also assisted with the integration of the new equipment into existing facility controls, procedures and the emer-gency shutdown system as well as on-site management and assistance with the system start up and com-missioning. The new system was in-stalled and commissioned last fall.

“Integrating the new piping and con-trols into both the Caterpillar G3516 and G3608 engine skids was a chal-lenge,” explained Pullig. “Not only did we upgrade starter inlet piping from 2 to 3 in. (51 to 76 mm) in only enough space for 2 in. (51 mm) pipe, but we also removed the starter and engine prelube vents from the existing gas units on the skid. We also encoun-tered things like the air header pres-sure being much higher — roughly 10 psig (0.7 bar) higher than the receiver pressure — on hot days due to the sun heating up the gray pipe.”

“Our focus is improving the eco-nomic performance of compression facilities and gathering systems, from a clean sheet of paper to a revamp of an existing facility and equipment,” said Wayne Sartori, president and founder of Denver, Colorado-based GCC. “Our expertise and experience in natural gas systems has allowed GCC to provide solutions to our cli-ents for small well head operations to large mainline gas processing and transportation systems.” CT2

n The starting air compressors supply three 2560 gal. (9691 L), 200 psig (13.8 bar) air receivers installed outside the compressor building.

OCTOBER 2013 44 COmpREssORtech2

n The 6 in. (152 mm) diameter starting air pip-ing was added to a busy pipe rack and utilized ex-isting pipe supports as much as possible.

CT267.indd 2 9/24/13 4:03 PM

Insight onsite.™

Harsco.indd 1 9/17/13 9:27 AM

Lubrication oil is one of the highest costs associated with the opera-tion of compressors. For the aver-

age compressor operator, oil usage can average 25 to 30% of running costs.

Managing these costs in today’s economy is more important, as ex-cessive lubrication erodes operators’ profitability as well as impacts the reli-ability of critical sealing components.

It is common practice to run break-in lubrication rates for new or overhauled compressors for a period of 200 hours after start-up. This break-in period pre-vents excessive temperature at start-up, allows conformity of piston and packing rings to mating surfaces and allows debris to be carried away.

It is very often the case that the lubri-cation levels are never scaled back to normal levels, especially in remote lo-cations. When operating a large fleet of compressors, there is significant profit

that can be gained through using an optimum lubrication system. There is an added cost of having this additional lubrication oil in the gas stream; the longevity of coalescing filters can be greatly improved when lubrication oil rates are set to the correct levels, pre-serving the life of the filters, increasing the profitability of an operation.

Excessive lubrication is equally damaging to reciprocating compres-sor sealing components. Increased oil lubrication can cause hydraulic locking of the packing case. This is where the packing rings do not have adequate side clearance and the rings overheat, extrude and ultimately fail. Another cause of over lubrica-tion is valve stiction. Excessive oil causes the sealing elements to stick to the valve seat. The valve opening and closing events are delayed and increased pressure causes the valve to open and close with increased ve-locity, which in worst cases can cause the elements to break.

Compressor Products International (CPI) has introduced the Proflo EOS to specifically address these problems by optimizing the amount of oil that is in-jected into a reciprocating compressor. CPI acquired three leading compres-sor lubrication companies in 2010, and the Proflo EOS has been developed as a result of the knowledge and insight gained from these acquisitions.

The Proflo EOS replaces the manual adjuster on a conventional lubrication pump. It has the ability to automatically increase or decrease the output of the pump by adjusting the stroke length of the pump. Traditionally, operators have to remove the rubber boot and screw the manual adjustment in or out, ad-justing the stroke of the pump while watching the changes in cycle time.

The Proflo EOS is installed in a CPI pump and monitors the amount of oil injected into the compressor through the use of a signal feedback loop from a CPI Proflo Jr. or captured proximity switch that is installed on the lubrication system divider block. The frequency of the pulses from the Proflo Jr. or captured proximity switch-es informs the Proflo EOS as to the change in quantity of oil.

The Proflo EOS displays all infor-mation about the status of the lubri-cation system on its main screen. The Proflo EOS is set up through the configuration of three key parameters. The first, the divider block cycle time set point, is the ideal number of sec-onds that it takes a divider block with the optimum level of lubrication being delivered to the compressor. The sec-ond parameter, the lubrication break-in hours, is the time during which twice the amount of lubrication oil is delivered to the compressor. The final parameter, the divider block total, al-lows the quantity of oil consumed to be calculated.

When the compressor is started, the

Eliminating Excessive Compressor Lubrication > CPI’s Proflo EOS optimizes the amount of

oil injected into a reciprocating compressorBy LEE ALExAndEr

n The Proflo EOS is designed to eliminate excessive lubrication by optimizing the amount of oil that is injected into a recipro-cating compressor.

OCTOBER 2013 46 COmpREssORtech2

Lee Alexander is Engineering Director – Americas at CPI.

CT274.indd 1 9/24/13 4:05 PM

Proflo EOS has the ability to operate in break-in mode and deliver increased lu-brication oil. After a user-defined period of time, the Proflo EOS automatically scales back the amount of oil delivered to give the desired cycle time. This is important so that maximum life from polytetrafluoroethylene (PTFE)-based wear products is achieved. Excessive oil for prolonged periods causes the PTFE based to wear too fast.

After the initial flow optimization is made, the Proflo EOS continually monitors the cycle time and makes appropriate adjustments. If debris or foreign material are introduced into the lubrication system, they can cause wear to the pump and the output de-creases. The Proflo EOS can make adjustments to maintain the cycle time. If significant adjustments have to be made, signaling severe damage to the lubrication, a warning can be gen-erated to notify the operator.

The Proflo EOS will display the configured divider block cycle time as well as the current and last mea-sured values. Real-time motion of the divider blocks and pump stroke and output utilization are displayed graphically to indicate they are op-erating correctly. In addition, the Proflo EOS presents status and alarm information via the Modbus 485 protocol that can be fed into an existing compressor panel or SCA-DA system to provide compressor operators real-time lubrication data.

The Proflo EOS has a stainless-steel body, O-ring sealed face plate, encapsulated motor and three in-

dividual printed circuit boards that meet global intrinsic safety hazardous location approvals, as well as hold up to harsh en-vironmental conditions.

The Proflo EOS has undergone extensive testing, including API 618 vibration stress; x, y and z shock; random vibration; half sine positive and negative vibration and shock profiles; highly accelerated live test-ing (HALT); and Ingress Protection

(IP66). This testing helped CPI validate the reliability of the product when in-stalled on a compressor in the harshest of conditions.

The Proflo EOS is Intrinsically Safe (IS) in construction; both European and North American Hazardous Location approvals are due to be completed in October. The intrinsic safety protection concept ensures that there is not suf-ficient energy in the electrical circuits to provide a source of ignition. CT2

OCTOBER 2013 47 COmpREssORtech2

n Real-time motion of the divider blocks and pump stroke and output utilization is displayed graphically to indicate they are op-erating correctly.

ECOM CN

ECOM EN2-F

ECOM J2KN-PRO

Emission Testing Made Easy

Rugged Reliable Accuratewww.ecomusa.com 1-877-326-6411

Ecom.indd 1 9/17/13 1:07 PM

CT274.indd 2 9/24/13 4:06 PM

RAISING PERFORMANCE. TOGETHER™

Get it all, right from the source.

F L O W E Q U I P M E N T L E A D E R S H I P

Cameron CT2 Camserv Ad.indd 3 3/14/13 11:19 AMCameron.indd 1 3/15/13 9:52 AM

Comprehensive capabilities. Passionate customer service.

One-source solutions. Sole OEM responsibility. Cameron’s

CAMSERV™ aftermarket team delivers total aftermarket

support for reciprocating compression and power equipment – from parts to emissions solutions,

engineering to field support, for any make or model – all from one convenient and attentive

source. We are a dedicated aftermarket team that exists to help customers keep their equipment

running efficiently, reliably and, above all, profitably. Cameron’s network of aftermarket facilities

consolidates parts sales and exchange, service, repair, remanufacturing and emissions upgrades

under one name. Learn more by calling 1.866.754.3562 or at www.c-a-m.com/cs.

Cameron CT2 Camserv Ad.indd 4 3/14/13 11:20 AMCameron.indd 2 3/15/13 9:52 AM

Displacement (D) Power Year Emissions Certification

D < 10 L per cylinder ≤ 3000 hp 2007+ Nonroad Tier 2/3/4

> 3000 hp 2007-2010 Nonroad Tier 1

2011+ Nonroad Tier 2/4

10 ≤ D < 30 L per cylinder All 2007+ Marine Cat. 2 Tier 2/3/4 (Tier 3/4 proposed)

D ≤ 30 L per cylinder All 2010-2011 Marine Cat. 3 Tier 1 (proposed)

2012+ Marine Cat. 3 Tier 2/3 (proposed)

Year Category CO NMHC NOx PM

2011 Gen-sets > 900 kW 3.5 (2.6) 0.40 (0.30) 0.67 (0.50) 0.10 (0.075)

All engines except 3.5 (2.6) 0.40 (0.30) 3.5 (2.6) 0.10 (0.075)

gen-sets > 900 kW

2015 Generator sets 3.5 (2.6) 0.19 (0.14) 0.67 (0.50) 0.03 (0.022)

All engines except gen-sets 3.5 (2.6) 0.19 (0.14) 3.5 (2.6) 0.04 (0.03)

Engine Power Year CO NMHC NMHC+NOx NOx PM

kW < 8 2008 8.0 (6.0) - 7.5 (5.6) - 0.4a (0.3)

8 ≤ kW < 19 2008 6.6 (4.9) - 7.5 (5.6) - 0.4 (0.3) (11 ≤ hp < 25)

19 ≤ kW < 37 2008 5.5 (4.1) - 7.5 (5.6) - 0.3 (0.22) (25 ≤ hp < 50)

2013 5.5 (4.1) - 4.7 (3.5) - 0.03 (0.022)

37 ≤ kW < 56 2008 5.0 (3.7) - 4.7 (3.5) - 0.3b (0.22) (50 ≤ hp < 75)

2013 5.0 (3.7) - 4.7 (3.5) - 0.03 (0.022)

56 ≤ kW < 130 2012-2014c 5.0 (3.7) 0.19 (0.14) - 0.40 (0.30) 0.02 (0.015) (75 ≤ hp < 175)

130 ≤ kW ≤ 560 2011-2014d 3.5 (2.6) 0.19 (0.14) - 0.40 (0.30) 0.02 (0.015) (175 ≤ hp ≤ 750)a - hand-startable, air-cooled, DI engines may be certified to Tier 2 standards through 2009 and to an optional PM standard of 0.6 g/kWh starting in 2010

b - 0.4 g/kWh (Tier 2) if manufacturer complies with the 0.03 g/kWh standard from 2012

c - PM/CO: full compliance from 2012; NOx/HC: Option 1 (if banked Tier 2 credits used) — 50% engines must comply in 2012-2013; Option 2 (if no Tier 2 credits claimed) — 25% engines must comply in 2012-2014, with full compliance from Dec. 31, 2014

d - PM/CO: full compliance from 2011; NOx/HC: 50% engines must comply in 2011-2013

Rated Power (kW) NMHC+NOx PM

kW < 8 4.6 (3.4) 0.48 (0.36)

8 ≤ kW <19 4.5 (3.4) 0.48 (0.36)

19 ≤ kW <37 4.5 (3.4) 0.36 (0.27)

37 ≤ kW < 75 4.7 (3.5) 0.24 (0.18)

75 ≤ kW <130 4.0 (3.0) 0.18 (0.13)

130 ≤ kW < 560 4.0 (3.0) 0.12 (0.09)

kW ≥ 560 3.8 (2.8) 0.12 (0.09)

Engine Category Emissions Alternative Standard CO/HCHO Reduction

Area Sources4SLB, Nonemergency > 500 hp 47 ppmvd CO 93% CO4SRB, Nonemergency > 500 hp 2.7 ppmvd HCHO 76% HCHO

Major Sources2SLB, Nonemergency 100 ≤ hp ≤ 500 225 ppmvd CO -4SLB, Nonemergency 100 ≤ hp ≤ 500 47 ppmvd CO -4SRB, Nonemergency 100 ≤ hp ≤ 500 10.3 ppmvd HCHO -Landfill/Digester Gas, Nonemergency 177 ppmvd CO - 100 ≤ hp ≤ 5004SRB, Nonemergency > 500 hp 350 ppmvd HCHO 76% HCHO

Engine Category Emissions Alternative Standard CO Reduction

Area SourcesNonemergency 300 < hp ≤ 500 49 ppmvd CO 70%Nonemergency > 500 hp 23 ppmvd CO 70%

Major Sources Nonemergency 100 ≤ hp ≤ 300 230 ppmvd CO -Nonemergency 300 < hp ≤ 500 49 ppmvd CO 70%Nonemergency > 500 hp 23 ppmvd CO 70%

Standards for spark ignition, gas-fired stationary engines are summarized in the table below. The engine designations indicate two- or four-stroke (2S/4S) lean- or rich-burn (LB/RB) gas engines.

Tier 4 Emissions Standards For Engines Up To 560 kW, g/kWh (g/bhp-hr)

NESHAP Emissions Requirements For Stationary Gas (SI) Engines

NESHAP Emissions Requirements For Stationary Diesel (CI) Engines

Emissions Requirements For Nonemergency Stationary Engines

Tier 4 Emissions Standards For Engines Above 560 kW, g/kWh (g/bhp-hr)

CANADAOn November 17, 2011, Environment Canada adopted amendments to the Off-Road Compression-Ignition Engine Emissions Regulations, which align Canadian emissions standards with the US EPA Tier 4 standards for nonroad engines, including the emissions limits, testing methods and effective dates. Most of these requirements are defined by reference to the pertinent sections of the US regulations. The Canadian Tier 4 standards came into force on January 16, 2012 and apply to engines of the 2012 and later model years manufactured on and after January 16, 2012.

Description NOx Limit, mg/Nm3

Spark ignition (Otto) engines, four-stroke, > 1 MWLean-burn engines 250

All other engines 500

Compression ignition (Diesel) engines, > 5 MWFuel: natural gas (jet ignition engines) 500

Fuel: heavy fuel oil 600

Fuel: diesel oil or gas oil 500

NOx Emissions Limits From New Stationary Engines

WORLD BANk GUIDELINESStationary EnginesThe maximum emissions levels are expressed as concentrations, to facilitate monitoring. The emissions limits are to be achieved through a variety of control and fuel technologies, as well as through good maintenance practice. Dilution of air emissions to achieve the limits is not acceptable. The following are emissions limits for engine-driven power plants:Particulate matter. PM emissions (all sizes) should not exceed 50 mg/Nm3;Sulfur dioxide. Total SO2 emissions should be less than 0.20 metric tons per day (tpd) per MWe of capacity for the first 500 MWe, plus 0.10 tpd for each additional MWe of capacity over 500 MWe. In addition, the SO2 concentration in flue gases should not exceed 2000 mg/Nm3, with a maximum emissions level of 500 tpd;Nitrogen oxides. Provided that the resultant maximum ambient levels of nitrogen dioxide are less than 150 µg/m3 (24-hour average), the NOx emissions levels should be less than 2000 mg/Nm3 (or 13 g/kWh, dry at 15% O2). In all other cases, the maximum NOx emissions level is 400 mg/Nm3 (dry at 15% O2).

NOx is specified as NO2 equivalent. Concentrations are expressed at standard temperature and pressure conditions (273.15 K, 101.3 kPa) and at an oxygen reference content of 5%.The limits do not apply to engines running less than 500 hr/yr. Start-up, shutdown and main-tenance of equipment are also excluded. Meeting the limits by lowering exhaust concentra-tions through dilution is not permitted.The Protocol also specifies emissions monitoring and reporting requirements.

GOTHENBURG PROTOCOLStationary Engine GuidelinesNOx emissions limits for new stationary engines specified by the Gothenburg Protocol are listed (applicable to all parties other than Canada and the U.S.A.)

UNITED STATESEnvironmental Protection Agency (EPA)

Stationary Diesel Engines

Other Provisions: NESHAPDiesel Fuel. The diesel rule requires the use of ultralow sulfur diesel fuel for stationary nonemergency engines greater than 300 hp with a displacement of less than 30 liters per cylinder. The regulation will be fully implemented by 2013.Crankcase Filtration. Stationary engines above 300 hp must be equipped with closed or open crankcase filtra-tion system in order to reduce metallic HAP emissions.

Nonroad Diesel Engines

EPA Voluntary Emissions Standards For Nonroad Diesel Engines, g/kWh (g/bhp·hr)

CT Emissions Insert.indd 1 9/23/13 11:00 AM

Cat. Net Power Date CO HC NOx PM kW g/kWh

L 130 ≤ P ≤ 560 Jan. 2011 3.5 0.19 2.0 0.025

M 75 ≤ P < 130 Jan. 2012 5.0 0.19 3.3 0.025

N 56 ≤ P < 75 Jan. 2012 5.0 0.19 3.3 0.025

P 37 ≤ P < 56 Jan. 2013 5.0 4.7† 0.025† NOx+HC

Cat. Net Power Date† CO NOx+HC PM kW g/kWh

H 130 ≤ P ≤ 5602006.01 3.5 4.0 0.2

I 75 ≤ P < 130 Jan. 2007 5.0 4.0 0.3

J 37 ≤ P < 75 Jan. 2008 5.0 4.7 0.4

K 19 ≤ P < 37 Jan. 2007 5.5 7.5 0.6

Dates for constant speed engines are: 2011.01 for categories H, I and K; Jan. 2012 for category J.

EuropEan unionStage 3/4 StandardsStage 3 standards — which are further divided into two substages: Stage 3A and Stage 3B — and Stage 4 standards for nonroad diesel engines are listed. These limit values apply to all nonroad diesel engines of indicated power range for use in applications other than propulsion of locomotives, railcars and inland waterway vessels, which are listed in their own tables. (See DieselNet.com for more details and inland waterway vessel data.)The implementation dates in the following tables refer to the market placement dates. For all engine categories, a sell-off period of two years is allowed for engines produced prior to the respective market placement date. The dates for new type approvals are, with some excep-tions, one year ahead of the respective market placement date.

Stage 4 Standards For nonroad Engines

Cat. Net Power Date CO HC NOx PM kW g/kWh

Q 130 ≤ P ≤ 560 Jan. 2014 3.5 0.19 0.4 0.025

R 56 ≤ P < 130 Oct. 2014 5.0 0.19 0.4 0.025

Stage 3B Standards For nonroad Engines

Category PM

CI liquid fueled 20

CI liquid fueled standbya 80

CI gas fueled (dual fuel) or SI no limit

a - emergency operation only or peak shaving operation for less than 300 hr/yr.

Category NOx†

≥ 3 MW < 3 MW

CI liquid fueled CI biogas (dual fuel) 0.5 1.0

SI biogas or SI lean-burn using other gas fuels CI (dual fuel) using other gas fuels 0.5

Other four-stroke Otto engines 0.25

Two-stroke engines 0.8† NOx limits do not apply to emergency engines or engines used for peak shaving for less than 300 hr/yr.

Engine Power (P) Date CO HC NOx PM Smoke g/kWh 1/m

P ≤ 19 kW Jan. 2004 5.0 1.3 9.2 0.6 0.7

July 2005 3.5 1.3 9.2 0.3 0.7

19 kW < P ≤ 50 kW Jan. 2004 5.0 1.3 9.2 0.5 0.7

July 2004 3.5 1.3 9.2 0.3 0.7

50 kW < P ≤ 176 kW Jan. 2004 3.5 1.3 9.2 0.3 0.7

176 kW < P ≤ 800 kW Nov. 2004 3.5 1.3 9.2 0.3 0.7

Category CO†

≥ 3 MW < 3 MW

All, excluding biogas and mine gas fueled 0.3

CI biogas (dual fuel) 0.65 2.0

SI biogas 0.65 1.0

SI mine gas 0.65† CO limits do not apply to emergency engines or engines used for peak shaving for less than 300 hr/yr.

The data presented in this insert is reproduced with permission from DieselNet.com. In spite of the care taken in the development of emissions standard information, the accuracy of data is not warranted. Visit www.dieselnet.com for more compre-hensive emissions data and additional information.

pM Emissions Limits For internal Combustion Engines, mg/nm3 @ 5% o2

nox Emissions Limits For internal Combustion Engines, g/nm3 @ 5% o2

Emissions Standards For Diesel Engines ≤ 800 kW for Generator Sets

Co Emissions Limits For internal Combustion Engines, g/nm3 @ 5% o2

GErManYThe Technische Anleitung zur Reinhaltung der Luft, in short referred to as TA Luft, is a regulation covering air quality requirements — including emissions, ambient exposures and their control methods — applicable to a number of pollutants from a range of station-ary sources. The TA Luft regulation, based on the “Federal Air Pollution Control Act”, has been introduced and is enforced by the German Environment Ministry BMU.Among other sources, the TA Luft regulation covers emissions of pollutants from stationary internal combustion engines. The TA Luft requirements have been widely applied to station-ary gas and diesel engines not only in Germany, but also in several other European markets.The TA Luft regulation was first introduced in 1986. The most recent revision, known as TA Luft 2002, was adopted on July 24, 2002. Compared to the previous requirements, TA Luft 2002 has introduced more stringent emissions limits for particulate matter, sulfur oxides, and nitrogen oxides from internal combustion engines.

All of the above engine emissions limits are expressed as dry gas concentrations at STP conditions, that have been corrected to a 5% oxygen content using the following formula:EB = EM × (21 - OB)/(21 - OM)where:EB - mass concentration of pollutant corrected for the reference O2 concentration,EM - measured mass concentration of pollutant,OB - reference O2 concentration, vol. %,OM - measured O2 concentration, vol. %.The TA Luft 2002 limits for diesel engines are rather strict. The NOx limit of 0.5 g/Nm3 typi-cally requires the use of SCR catalysts on large diesel engines.Sulfur Regulations. According to TA Luft 2002, a liquid fired stationary engine is to burn a light fuel oil according to DIN 51603 Part 1 (March 1998) containing max. 0.2% (wt.) sulfur and with a lower heating value > 42.6 MJ/kg, or to reach an equivalent SO2 limit by installing a flue gas desulfurization unit. The equivalent SO2 limit resulting from the above fuel require-ment is about 110 mg/Nm3 @ 15% O2 = approx. 300 mg/Nm3 @ 5% O2.

inDia

Date CO NMHC NOx PM mg/Nm3 mg/Nm3 ppm(v) mg/Nm3

Until June 2003 150 150 1100 75

July 2003 - June 2005 150 100 970 75

July 2005 150 100 710 75

Emissions Limits For Diesel Engines > 800 kW for Generator Sets

Engines are tested over the five-mode ISO 8178 D2 test cycle. Smoke opacity is measured at full load.

Stage 3a Standards For nonroad Engines

COMPRESSORDedicated To Gas Compression Products & Applications

CT Emissions Insert.indd 2 9/23/13 11:01 AM

OCTOBER 2013 52 COmpREssORtech2

Recent OrdersQGC

Coal seam gas producer QGC has awarded the Australian construction firm Thiess an AU$1.8 billion contract for the construction of gas compres-sion facilities and associated works for the Queensland Coal liquefied natural gas project in the Surat Basin.

The contract significantly expands Thiess’ role in the project, which now includes construction of all 18 field-compressor stations and four central processing plants by November 2014.

QGC (formerly Queensland Gas) will collect coal seam gas and move it via pipeline 340 mi. (547 km) to Curtis Island, off the shore of Gladstone in Central Queensland. There, the gas will be liquefied and exported.

Rolls-RoyceRolls-Royce has received a US$175

million contract to supply Asia Gas Pipeline (AGP) with compression

equipment and services for Kazakh-stan’s Line C gas pipeline, part of the 1140 mi. (1833 km) Central Asia- China Gas Pipeline network.

Rolls-Royce will supply AGP, a joint venture between Kazakhstan’s KazMunaiGaz and China’s National Petroleum Corp. (CNPC), with 12 RB211 gas turbine-driven pipeline compressor units for four compressor stations on the C Pipeline.

When it reaches full capacity in 2016, the Central Asia-China Gas Pipeline network will move 1.94 Tcfy (55 x 109 m3/yr) from Turkmenistan and Uzbekistan through Kazakhstan to China. The Line C Pipeline in Ka-zakhstan will be about half of the total capacity and may supply gas domesti-cally to Kazakhstan.

The latest contract is in addition to 11 RB211 gas turbine-driven compressor units ordered from Rolls-Royce in 2009 for the A and B pipelines. CT2

It’s not magic…it’s physics.

HOERBIGER Engine Solutions

Find an Altronic Distributor near you at www.altronic-llc.com

Our new Passive Pre-Chamber (PPC) sparkplugs are designed specifically for each application. They provide the combustion assurance you need without the cost and complexity of traditional precombustion chambers.

PPC models for the Caterpillar G3500 family of engines are available now, and models for other engine families—including slow-speed integrals—are coming soon. Learn about the NOx reduction and fuel efficency gains possible today.

Altronic.indd 1 4/18/13 1:00 PM

MOveRsPRIMEGE Oil & Gas

GE Oil & Gas has completed its ac-quisition of Salof Co., a Schertz, Texas-based designer of small-scale liquefied natural gas (LNG) technologies.

Salof is known for its cryogenic plant design and fabrication for small LNG and CO2 applications. GE said it has recently launched LNG solutions with a smaller footprint and capacity, and Salof’s complementary offerings will add additional capabilities and manufacturing footprint while enabling Salof to draw upon GE’s breadth and global operations.

MonicoMonico has promoted Steve Ran-

som to application sales engineer and added Matthew Koshinski and Steve Neal to its sales staff. Ransom, who has a mechanical engineering background, was the first member of Monico’s staff. Koshinski joins Moni-

CT275.indd 1 9/24/13 4:09 PM

OCTOBER 2013 53 COmpREssORtech2

It’s not magic…it’s physics.

HOERBIGER Engine Solutions

Find an Altronic Distributor near you at www.altronic-llc.com

Our new Passive Pre-Chamber (PPC) sparkplugs are designed specifically for each application. They provide the combustion assurance you need without the cost and complexity of traditional precombustion chambers.

PPC models for the Caterpillar G3500 family of engines are available now, and models for other engine families—including slow-speed integrals—are coming soon. Learn about the NOx reduction and fuel efficency gains possible today.

Altronic.indd 2 4/18/13 1:00 PM

MoversPRIMEco from Caterpillar, having served in its Global Petroleum and Engineer - ing departments.

Neal has more than 29 years of sales experience in the oil and gas industry, working for B-Line Fiber and Supply, Perry Equipment Co. and Permian Filters.

HoerbigerHoerbiger has named Don York

president of Hoerbiger Corp. of Amer-ica Inc. and Mat Castaneda as senior vice president and head of Hoerbiger Service Inc.

York will lead the business and operational strategies for the compa-ny’s manufacturing facilities in Flori-da and Texas. He succeeds Hannes Hunschofsky, who will head global operations for Hoerbiger Compressor Technology’s Production Division. York joined the company in October 2011 as senior vice president and

chief operating officer for the U.S. compressor valve manufacturing facility in Pompano Beach, Florida, and the rings and packing manufac-turing facility in Houston. He was named president of Hoerbiger Serv-ices in 2012.

Castaneda will lead the company’s service network in the United States. He has held leadership roles at Solar Turbines, Wood Group, GE Packaged Power and FMC Technologies.

SEC Energy Products & Services

Tommy Stone has been named president of Houston-based SEC Energy Products & Services (SEC), replacing Bo Pierce, who has left the company.

Stone will oversee an expansion of SEC’s facilities and services in Houston and across the nation. The company plans to double its produc-

tion capabilities and workforce by 2014.

SEC provides natural gas com-pression equip-ment, parts and services. It also offers engineer-ing services such

as package design, procurement, construction, installation, inspection, project management, mechanical, in-strumentation and electrical.

Stone, 54, is a 30-year gas in-dustry veteran. He began his ca-reer with Texas Eastern Transmis-sion Corp., which later was merged into Trunkline Gas Co., now a part of Energy Transfer Partners (ETP). He later became vice president of Trunkline LNG Co. Most recently, Stone was senior vice president of operations for ETP.

T. Stone

CT275.indd 2 9/24/13 4:10 PM

OCTOBER 2013 54 COmpREssORtech2

This article addresses founda-tions for high-speed, separable, reciprocating compressors from

1000 to 5000 hp (745 to 3728 kW) with operating speeds of 720 to 1200 rpm. In many cases, such foundations and their compressor package attachment methods are not being adequately de-signed, specified and installed.

IntroductionShale gas production assets have

increased by about 50% in Pennsylva-nia, West Virginia and Ohio during the last 12 months. This large increase in natural gas production requires short

schedules for compressor station de-sign and construction.

There are two basic foundation cat-egories for these reciprocating com-pressors: short-term temporary foun-dations with operation periods of two years or less; and long-term perma-nent foundations with life expectancies greater than two years and often more

than 20 years. Unfortunately, short-term foundation designs are initially utilized for temporary projects that are extended to long-term projects when future additional wells are added.

Short-term, low-budget foundations create excessive vibration due to inef-fective foundation designs and inade-quate package attachment methods. In most cases, such short-term designs and attachment methods result in high vibration, unscheduled shutdowns and require significant modifications to achieve long-term compressor station operating life of two to 20 years.

continued on page 56

EffEctivE foundations, Anchor Bolts And Grouting For Recips Careful preparation

is essential for long-term performance

By GeOff AnderSOn,

BOB rOWAn And

Jeff BUTler

CT271.indd 1 9/23/13 4:36 PM

Bringing energy and the environment into harmony.®

75412 DR Midstream Ad for Compressor Tech Two — Full Page, 4/C, B: 8 1/4”w x 10 3/4”h, T: 8”w x 10.5”h, L: 7.5”w x 10”h

The Americas: (Int’l +1) 713-354-6100 / EMEA: (Int’l +33) 2-35-25-5225Asia-Pacifi c: (Int’l +60) 3-2093-6633 / info@dresser-rand.com

Compressors–Turbo & Recip / Steam Turbines / Gas Turbines / Engines / Control Systems / Expanders

WE’RE HUNGRY TO PROVE OUR STRENGTH IN MIDSTREAM.Through strategic acquisitions and increased investment in R&D and people, Dresser-Rand® has the strength to better serve your midstream requirements. With our signifi cant percentage of installed base, a long history in gas transmission, gathering and storage, and our advanced technology, Dresser-Rand is committed to support our clients in the midstream.

Our unique, environmentally friendly Dresser-Rand Enginuity® technology can provide improved effi ciency and reduced emissions from new and existing engines and compressors. And with its integrated and totally enclosed confi guration, along with its use of magnetic bearings, our DATUM® C compressor (photo at right) offers signifi cant environmental benefi ts. After all, our focus is on total solutions, not just new units or parts. Contact Dresser-Rand—for powerful support, ferocious loyalty and a real hunger to help you succeed.

» www.dresser-rand.com

Visit us at The GMRC Gas Machinery Conference, Booth 303, Albuquerque, NM, October 6-9and ADIPEC 2013, Abu Dhabi, UAE, November 10-13

75412_DR_MidstreamAd_CTT.indd 1 9/13/13 11:17 AMDresserRand_Bear.indd 1 9/17/13 10:58 AM

OCTOBER 2013 56 COmpREssORtech2

Short-term (ineffective) foundations

The following short-term foundation designs are not adequate to dissipate typical unbalanced forces generated by reciprocation compressors and prevent problems due to excessive vibration:

• Gravel pad — skid set on gravel pad with no attachment method (Figure 1).

• Sand pad — skid set in sand box with no attachment method.

• Concrete foundation with isolation pads — skid set on concrete with isolation pads (such as Solatex) do not provide an adequate at-tachment method (Figure 2).

• Concrete foundation and inad-equate attachment anchor bolts — skid attached to concrete foun-dation block without anchor bolts or with inadequate anchor bolts (Figure 3).

• Concrete foundation and inadequate grouting — skid attached to concrete foundation block without grouting or with inadequate grouting.

All of the listed foundation types may be suitable for short-term operation with skid support and piping modifications after start-up. However, they normally do not meet industrial vibration guide-lines. Short-term foundations will have high vibration, higher maintenance costs and incur potential safety hazards.

These designs do not have ample energy paths to allow the unbalanced forces to be transmitted into a founda-tion design that can dissipate such forces and prevent excessive vibra-tion. In other words, there are not suf-ficient energy paths from the equip-ment to the foundations.

Such excessive vibration occurs be-cause the unbalanced forces will find some component that is in resonance

and allows the energy to be dissipated as high vibration. Typical vibration fail-ures occur in instrumentation, small-bore piping, pressure-vessel connec-tions and relief valves.

Short-term (noneffective) founda-tion designs and skid support meth-ods should not be utilized for long-term applications in excess of two years operation. Anticipated long-term projects can be completed with long-term foundations and the compres-sors can be installed in phases as ad-ditional wells are brought in.

Long-term (effective) foundationsA long-term, effective foundation

design should consider the following design areas:

• Soil geotechnical considerations,• Low and even foundation equip-

ment settlement,• Suitable anchor bolt design and

attachment,• High-strength concrete and suffi-

cient rebar,• Finite element analysis (FEA) foun-

dation and equipment modeling,• FEA stress, natural frequency and

vibration analysis,• Adequate grout support and

installation.

Soil geotechnical considerationsThe purpose of a geotechnical soils

report is to explore the subsurface con-ditions at the compressor station site

continued on page 58

Figure 1 Photo shows gravel pad installation.

Figure 2 isolation pads on a concrete foundation do not provide adequate attachment.

Figure 3 grout and anchor bolts also may be inadequate.

CT271.indd 2 9/23/13 4:36 PM

ompressor Elements is your quality source for fast gas compressor machining and repairservices. Our large inventory of standardreplacement parts allows same day service in most cases.

We also manufacture compressor parts toyour exact specifications.

Our Quality Control department carefullychecks precise tolerances. To save valuable timewe maintain an archive of all your past repairs,ring and valve specifications, groove dimensionsand weights, etc.

And, as with all Compressor Elements’ partsor repairs, your job is guaranteed.

Call us today for … • Compressor cylinder

relining• Pistons and rods• Piston rings and

rod packing• Compressor valves

Compressor Elements has extended it’s servicearea into the Barnett shale gas play with amachine shop service center and parts ware-house in Granbury. To further our commitment toserving and expediting your needs, we added a25,000 sq. ft. machining and warehouse facility atour Monahans location.

1-800-533-3849

35 YEARS SERVICE

TO THE GAS

COMPRESSION

INDUSTRY

• Thread rolling• CNC machining• Repair parts • Used and refurbished

compressors• Gas compressor packaging

200hp - 1500hp

CC

Granbury, Texas5733 Acton Circle • Granbury, TX 76049

(817) 326-3663rmyers@compressorelements.com

Monahans, Texas2306 S. Stockton • Monahans, TX 79756

(432) 943-6701sswarb@compressorelements.com

Experienced Machining!

CompressorElements.indd 1 8/13/13 1:19 PM

OCTOBER 2013 58 COmpREssORtech2

to enable an evaluation of acceptable foundation systems and foundation de-sign. This includes the following, which change soil composition in layers:

• Field exploration with soil boring holes drilled 35 to 60 ft. (10.7 to 18 m) that provide a description of major soils strata directly under the foundation location,

• Describe moisture content and any ground water tables,

• Make recommendations as to soil-bearing loads, site preparations, soil shrink-swell potential and foun-dation recommendation.

The purpose of a crosshole seis-mic soils report is to determine the actual dynamic properties of the soils at the compressor station site to en-able a natural frequency analysis and a vibration amplitude analysis of the foundation-soil system. This includes the following:

• Field exploration with three soil borings holes (3 in. [76 mm] in-ternal diameter with PVC casing) down to 40 ft. (12 m) to provide the following soil data every five feet: compression seismic velocity, shear seismic velocity, constrained modulus, shear modulus, Young’s modulus, and Poisson’s ratio,

• One electromechanical source and two three-component, triaxial geo-phones receivers should be utilized,

• Field soil samples should be tak-en at locations directly under the compressor foundations. Based on the geotechnical report and crosshole seismic report, Tech Transfer Inc. will utilize soil prop-erties and layer distribution to

determine the various foundation support design and soil support stiffness for dynamic analysis.

Recommendations for soil prepara-tion, backfill and concrete pier design, will be made and submitted for approval,

The side and bottom soil proper-ties that support the foundation and pilings will be simulated as springs. A range of spring stiffness values will be calculated, and are based on varying the shear modulus.

Foundation settlementFoundation settlement must be de-

termined by the foundation design load on the soil, which should not exceed 1500 psf (pounds per square foot) (0.7 bar). If initial foundation settle-ment calculations result in greater than 0.50 in. (12.7 mm) of combined initial and long-term settlement, drilled pilings may be required to reduce settlement.

In order to generate even long-term settlement across the entire foundation with the equipment installed, the center of gravity (COG) of the mounted equip-ment must be near the COG of the con-crete foundation block. The following tolerances should be incorporated: lon-gitudinal tolerance equals 5% or 12 in. (30.5 cm) max and transverse tolerance equals 2.5% or 6 in. (15.2 cm) max.

Skid anchor bolt locationsSkid anchor bolt locations are an

important consideration when devel-oping energy paths to transmit unbal-anced forces thorough the compres-sor skid and into the foundation.

Such locations are normally at the perimeter of the load-transmitting skid

beams. As a minimum, skid anchor bolts should be located at the follow-ing perimeter locations, as shown as blue dots in Figure 4:

• Corners of main skid, scrubber outrigger boxes and pipe support outriggers,

• Ends of main transverse beams under compressor and driver feet,

• Ends of main transverse beams under scrubber support plates,

• Ends of main transverse beams under skid-mounted coolers,

• Ends of main transverse beams under crosshead supports,

• Ends of main longitudinal beams at both ends of the skid.

In addition, the skid dynamic natu-ral frequency analysis may require in-ternal split anchor bolts, which move the skid structural natural frequencies a minimum of 20% above 1x and 2x the compressor operating range (red location dots in Figure 4).

The anchor bolt clamping force re-sulting from bolt tightening must be considered in the concrete foundation stress-analysis calculations. Normally, this force is achieved by tightening the nuts to produce approximately 70 to 80% of the bolt proof load. This is normally the highest stress location in the entire foundation block and/or pedestal. A typical 1.125 in. (28.6 mm) anchor bolt clamping force is approxi-mately 54,000 lb. (24,494 kg). Normal bolt-nut relaxation will be 10 to 15% of the applied torque values.

The anchor bolt clamping force cre-ates a large amount of skid frictional resistance, which is so great that shear force from the skid never reaches the anchor bolt itself. With properly located and torqued anchor bolts, the applica-tion of the operating shear and seis-mic forces directly on anchor bolts will not occur.

High-strength concrete and sufficient rebar

The concrete foundation should be designed in accordance with the Ameri-can Concrete Institute (ACI) Specifica-tion 318-11, and the guidelines in ACI 351.3R-04. The concrete strength should be 4000 psi (275 bar) with a 28-day cure time. There should be a 2 in. (5 cm)

Figure 4 Diagram shows anchor bolt attachments.

CT271.indd 3 9/23/13 4:36 PM

cover over the rebar on all sides and a 3 in. (76 mm) cover over the rebar on the top and bottom surfaces.

Design and construction form-work should be in accordance with ACI 347. All exposed concrete and grout edges should have 1x1 in. (2.54x2.54 cm) chamfers.

All reinforcing steel bars should be grade 60 (60 KSI yield strength) and meet ASTM 615. Reinforcing bar detail-

ing should be in accordance with ACI 318 and ACI 315. The minimum rebar size for reciprocating compressor foun-dations should be 0.75 in. (1.9 cm) (#6).

It is critical that the bottom anchor bolt discs be enclosed in a 3-D rebar cage to prevent crack propagation during long term settlement.

Rebar should be in 3-D layers of 12 in. (30.48 cm) transverse centers, 12 in. (30.48 cm) longitudinal centers and verti-

cal centers of 6 in. (15.24 cm) on top, 9 in. (22.86 cm) upper-mid layers and 12 in. (30.48 cm) in lower layers (see a typical compressor foundation rebar configura-tion in Figure 5 and photo in Figure 6).

FEA analysis modelingA 3-D finite element model of the

analysis foundation design with the block-mounted equipment should be

OCTOBER 2013 59 COmpREssORtech2

continued on page 60

FigurE 5 This drawing depicts sufficient rebar for a pad.

FigurE 6 This is a photo of field rebar installation for a compressor pad.

FLP_JanFeb.indd 1 12/19/12 2:53 PM

CT271.indd 4 9/23/13 4:37 PM

completed. The software program should show reliable and proven usage for at least five years. In ad-dition, the program modeling tech-niques must be accurate with proven comparisons to field dynamic vibra-tion readings.

The major equipment will be mod-eled as plates and/or solids with the actual equipment weight and center of gravity.

Static weight of all other foundation-mounted components is included in the model. Rebar, anchor bolts, scrub-ber support plates and bottle wedge support plates will be accurately mod-eled as individual members. The sole-plates will be modeled and attached to the anchor bolts.

The side and bottom soil properties will be simulated as springs. A range of spring stiffness will be utilized, and is based on varying the shear modu-lus. Soil bearing pressure and safety factors will be calculated. Long-term soil settlement will be calculated.

Static stresses and deflections of the foundation concrete and rebar mem-bers will be determined and analyzed in accordance with ACI 318.

Natural frequency analysisConduct dynamic analysis to deter-

mine structural natural frequencies of existing foundation design with the block-mounted equipment installed. Structural natural frequencies will be analyzed to ensure that there are no coincidental resonances at 1x and 2x the compressor operating speed range. This is required because the engine and compressor generate sig-nificant unbalanced forces at 1x and 2x operating speed.

Vibration analysisThe compressor unbalanced cou-

ples and forces will be calculated and located in the model at pseudo crank-shaft locations and crosshead sup-ports. These unbalanced forces will include those generated from both me-chanical inertia and gas compression sources. These unbalanced forces are transmitted into the skid through the FEA compressor frame feet and cylin-der crosshead supports.

Engine unbalanced couples and forc-es from mechanical inertia at maximum machining tolerances and those due to “roll torque frequencies” should be ob-tained from the engine manufacturer and located in the engine model.

Vibration levels should be moni-tored throughout the structural model and compared to field vibration guide-lines. One such common guideline is 2.0 mils (0 to peak). Redesign of the skid-foundation system should not be completed until acceptable vibration levels can be achieved.

Anchor bolt materialsBecause shaking forces are some-

what unpredictable, even for items such as scrubbers and coolers, high-strength alloy steel meeting ASTM A193 Grade B7 (125,000 psi tensile) should be specified for compressor foundations.

This has the advantage of providing additional clamping force if needed to control shaking forces, and typically is manufactured with rolled threads. An-chor rods meeting this specification are generally priced competitively to lower strength Grade 55 ASTM 1554 anchor rods with cut threads.

Anchor bolt sizing criteriaCorrect anchor bolt sizing methods

consider the material and clamping force necessary to hold the skid down to the foundation to ensure vertical support, horizontal friction, and dy-namic stiffness. The reaction forces are transmitted into the foundation at the anchor bolt locations.

However, the anchor clamping force is so much greater than the reaction forces, which only vary the clamping force load by 10 to 20%. Therefore, skid reaction forces at the anchor bolts should not be uti-lized as a major criterion for founda-tion design. The anchor bolt reaction forces generate low concrete stress and do not address energy paths within the foundation or dissipation of unbalanced energy.

Skid anchor bolt diameters are nor-mally determined by the compressor package skid designer with a clear-ance of 0.0625 in. (1.6 mm) on all sides (0.125 in. [3.2 mm] total). The

minimum anchor bolt diameter for re-ciprocation compressor skids should be of 1.125 in. (28.6 mm).

In order to develop sufficient stretch and locate the bottom disc of the skid anchor bolt in a lower stress section of the concrete foundation, they should be a minimum of 36 in. (91.4 cm) in total length.

The practice of staggered lengths of anchor bolts (in the mistaken belief this practice will minimize connecting cracking) should be avoided. Proper rebar detailing is the only way to con-tain the cracking that can start at the lower anchor rod plate/disk. Such de-tailing eliminates crack propagation horizontally, and is recommended in various ACI and ASCE documents.

Anchor bolt design and styleAnchor bolts for auxiliary equip-

ment such as bottle supports, scrub-bers and coolers can be a straight an-chor rod with a thick bottom plate/disk with a full length sleeve to allow for full length stretch.

For exterior skid beam grouting, a canister design that provides a variable anchor rod projection and horizontal alignment (to allow center-ing in the skid anchor bolt hole only 0.125 in. [3.2 mm] larger than the anchor rod) should be specified. This style allows full retraction of anchor bolts below the top of the concrete, which allows horizontal skid place-ment on rollers when unloading off a truck trailer.

For internal anchorage of the interi-or longitudinal wide flange skid beams supporting the compressor and the driver, a coupled canister-style an-chor bolt design allows the top anchor rod/stud, which typically terminates at the top flange of the longitudinal wide flange, to be removed during the skid package placement.

Spherical washers should be speci-fied under the top anchor rod nut. Even a perfectly installed straight anchor bolt can become misaligned during operation from thermal expan-sion. A double spherical washer helps correct for the bending stress that can develop with a flat washer.

OCTOBER 2013 60 COmpREssORtech2

continued on page 62

CT271.indd 5 9/23/13 4:37 PM

www.nidec-asi .com

Demir dreams of improving his Company business and the welfare of his country, by converting his industrial power supply to gas,

he hopes to do both.

Nidec ASI, turning dreams into results.

Nidec ASI

Synchronous Generator

Gas pipeline,Russia-Turkey

Our customer’s dream was to build one of the deepest

pipelines in the world across the Black Sea, with depths

as low as 2.2 kilometres (1.4 mi).

Nidec delivered.

The on-board generation system ensured laying operations

performance of up to 3000 meters of pipe per day with a high level of reliability and precision under harsh environmental conditions

(deep waters, presence of corrosive elements and geological hazards).

Nidec.indd 1 6/7/13 2:39 PM

Anchor bolt templatesA precision steel anchor bolt in-

stallation template, with holes opti-cally set to 0.0625 in. (1.6 mm), is an often-overlooked requirement. Anchor bolt sleeves are not provided to allow bending of the anchor bolt, only to allow anchor bolt stretch. Un-der no circumstance should field per-sonnel be allowed to try to bend an anchor bolt.

The above pictures show a steel template strong enough to support the entire weights of each anchor bolt assembly without deflection, and drilled template holes exactly in the proper location.

Installation protectionAll properly designed slide anchor

bolts for both the main skid anchoring and the smaller auxiliary equipment anchor bolts have a long sleeve around the anchor rod up to the top of concrete.

A foam donut is typically at the top to temporarily keep concrete out of the sleeve during concrete place-ment, but should also be further pro-tected in the field by an application of silicone caulk and tape over the foam donut and also tape around the exposed upper anchor bolt projection (Figures 7 and 8).

Grout types, recommendationsFor skid-mounted gas compres-

sors, the correct type of grout material should be an epoxy grout with a mini-mum compressive strength of 9000 psi (620 bar), which covers most all com-

mercially available epoxy grout in the market today.

However, compressive strength alone should never be the only se-lection criteria; much more important is the ability of the grout to flow hori-zontally, without reducing aggregate quantity in the mix below the ven-dor’s standard shipment packaging.

It is recommended to use a head box to flow 15 to 18 ft. (4.6 to 5.5 m) hori-zontally with a nominal 2 in. (5.1 cm) clearance between the bottom of skid beam flange, and the rough, chipped top of the concrete foundation.

Equally important to good flow properties are a lack of foaming and good surface support underneath the flanges of the skid beams.

Figure 9 shows excessive bubbling and poor surface contact when a contractor decided to reduce the ag-

gregate ratio to try to get better flow, which was rejected by the client.

Grout flow propertiesGood flow properties of epoxy grout

are very brand-specific. Most com-mercial epoxy grout brands list in their literature a standard shipping unit typi-cally with four bags of a silica aggregate (Part C), a 3 gal. (more or less) (11 L) pail of epoxy resins (Part A) and a smaller amount of the Part B hardener/catalyst. Physical properties for a four-bag mix are listed.

If the particular brand has been de-signed for a reduced aggregate ratio (a three-bag mix), be sure the physical properties for a three-bag mix are also listed in the literature. Most commercial epoxy grout brands will not guarantee the product unless all four bags are mixed. If you see the wording, “Contact

OCTOBER 2013 62 COmpREssORtech2

FIGure 7 This shows a steel anchor bolt template.

FIGure 8 In this photo, the top of the anchor bolt is weather-proofed.

FIGure 9 This grout has bubbled due to reduced aggregate.

CT271.indd 6 9/23/13 4:38 PM

OCTOBER 2013 63 COmpREssORtech2

the factory before using a reduced ag-gregate mix,” find another brand.

Remember, the epoxy grout has to flow horizontally 15 to 18 ft. (4.6 to 5.5 m) over rough chipped concrete with only a clearance of 2 in. (5.1 cm). Often in the most critical support area under-neath the compressor, the skid beams have been filled internally with concrete to increase the mass. Only a commer-cial brand with published three-bag

properties should be used for such a tight demanding and important support point. Do not allow placement from both sides of the skid in order to cut the flow distance in half. Too many times this has left a critical void under the center of the skid (Figure 10).

The Figure 11 photo was taken af-ter excessive vibration shut down the machine. In the forensic investigation, holes were cut in the floor plate to allow

a visual inspection, which showed the internal void due to pouring grout from both sides of the skid. The weld splatter is from the cutting skid inspection hole.

Lifting the skid and regrouting to correct a poor placement is extremely expensive, time consuming and often results in a lawsuit. Choose the right epoxy grout and the right grouting contractor and do it right the first time.

continued on page 64

Figure 10 inadequate grout flow has created a void.

Figure 11 This shows a gap between the skid and the grout.

In 2013, 1000+ references in O&G

This offering is part of the SKF BeyondZero portfolio of products, services and solutions designed to help our customers reduce environmental impact. To learn more, visit www.beyondzero.com

Want the world leader? Specify SKF S2M Magnetic BearingsThe product of technology developed for space research, SKF S2M Magnetic Bearings continue to set the standard for oil-free, contact- free rotation.

Today, 99% of the turboexpanders and integrated e-motor compressors with magnetic bearings are equipped with SKF S2M. These machines are running in extremely diversifi ed environments – from arctic to offshore and desert areas.

For more information, visit SKF.com/S2M or scan this QR code.

Visit us at ADIPEC!French pavilion, Booth #9220 FUAE, Abu Dhabi – 10-13 November

SKF.indd 1 9/23/13 4:11 PM

CT271.indd 7 9/23/13 4:38 PM

Preparation prior to equipment placement

Prior to placing the equipment on the new concrete foundation, there are several tasks that need to occur in or-der to assure the continued success of the project.

These tasks include proper con-crete surface preparation, protection of the anchor bolts from the grout pour, placement of jackscrew landing pads and the layout and placement of expansion joints.

Preparation for placement of the equipment as described in the follow-ing paragraphs will help prevent stress cracking, expansion cracking, delami-nation at the concrete and grout inter-face, anchor bolt failure and edge lifting or edge curl cracks.

Concrete surface preparationDuring the curing process, a resi-

due of weak and nondurable mate-rial consisting of cement, aggregate, fines, or impurities rises to the surface of concrete. This process occurs as the material changes from a fluid to a plastic state.

The dynamic, shear, and tensile forces transferred from the equip-ment through the foundation require a strong bond between the epoxy grout and the concrete surface. If the latent concrete is not removed, the concrete will not have sufficient tensile strength needed to obtain the required bond strength between the two substrates.

Roughening the concrete surface and removing the surface laitance

prior to grouting is best accomplished through the use of lightweight pneu-matic chipping hammers equipped with chisel or moil point bits.

There are many other options com-monly used for preparing the concrete surface, including sandblasting, scari-fiers, scabblers, acid etching, and bush hammer bits. However, none of these options should be accepted.

Chipping hammers with chisel or moil point bits will properly remove the latent concrete without damaging the founda-tion and will provide the optimal peak-and-valley surface profile that affords the greatest bond (Figures 12 and 13).

The recommended depth of material removal is a function of the amount of water released during the curing pro-cess as well as how the concrete was finished. As a general rule of thumb, the aggregate that is exposed during this process should be broken and the surface should have a clean and ag-gressively roughened appearance.

The best time to complete the con-crete surface preparation is within a day or two of the equipment being placed and grouted. Waiting to pre-pare the surface until this time period helps to assure the concrete under the equipment will be clean and free of dirt, debris, and other contaminants that can be the result of weather conditions and foot traffic.

Protecting anchor boltsProperly designed anchor bolts will

be installed with a long sleeve, pro-tecting them from the concrete and

grout pour and allowing the necessary stretch required to obtain the optimum clamping force.

Prior to placement of the equipment onto the foundation is the best time to protect the anchor bolts as well as seal the sleeve to assure this impor-tant design feature remains. In order to avoid potential foundation damage resulting from freeze/thaw cycles, any water that has penetrated the anchor bolt sleeve should be removed with a vacuum device at this point.

Once the anchor bolt canisters are dry, the top can be sealed with an expanding spray foam product and wrapped with pipe insulation and duct tape to assure the required stretch of the anchor bolt is not restricted by the epoxy grout upon cure.

Jackscrew landing padsUsing round 3.0 in. (7.62 cm) di-

ameter steel jackscrew landing pads with beveled edges and a minimum 0.5 in. (1.27 cm) thickness is sufficient to prevent jackscrews from punching through a concrete foundation dur-ing leveling and adjustment for most skid-mounted equipment. The use of a landing pad that is square-shaped for the jackscrews must be avoided.

Geometric discontinuities cause an object to experience a local increase in the intensity of a stress field. An ex-ample of a shape that will cause these stress concentrations is a sharp or square corner.

A material can fail, or crack, when a

OCTOBER 2013 64 COmpREssORtech2

continued on page 66

Figure 12 Workers are chipping a foundation surface.

Figure 13 This chipped surface has jackscrew pads.

CT271.indd 8 9/23/13 4:39 PM

Trust the #1 online monitoring system for mission-critical equipment

Who monitors the most reciprocating compressors?

When you look at the numbers, it all adds up to PROGNOST Systems:

• Largest installed base of online diagnostic systems on reciprocating compressors• The world’s top refi ners and HPI producers trust PROGNOST® systems• Over 20 years of experience in monitoring reciprocating machinery

PROGNOST has one focus – reciprocating machinery. Our dedication ensures that your system remains best-in-class.

Intelligence on Duty

reply@prognost.com www.prognost.com

Prognost.indd 1 6/7/13 11:42 AM

concentrated stress exceeds the mate-rial’s theoretical cohesive strength. Fa-tigue cracks always start at the stressed location, so removing the cause and using round, rather than square, jack-screw pads greatly reduces the risk of a stress-related failure (Figure 14).

Expansion jointsExpansion joints (Figure 15) are

needed in epoxy grout pours to ac-commodate movement related to the expansion and contraction caused by temperature variations. An effective expansion joint design will allow tem-perature related movements to occur without inducing an unplanned stress crack that will need attention and main-tenance throughout the foundation’s service life.

An effective expansion joint design will have spacing between the joints of 4 to 5 ft. (1.2 to 1.5 m) along the entire length of the skid. Careful attention should be given to avoid placement in close proximity to anchor bolts and jackscrews, as well as placement in an area that would limit the ability to place grout under the equipment from planned pour locations that have been designed into the skid.

In the field, expansion joints are often an afterthought, and once the equipment is placed and the joints have not yet been placed, expansion joints may be viewed as an expendable component when considering the high crane and labor costs associated with removing and resetting the equipment. Properly placed expansion joints within the epoxy grout pour area are a critical part of the final foundation and serve the following two functions:

• Provide a controlled area for ex-pansion and contraction. Without expansion joints, the epoxy grout cap will find its own expansion in the form of a stress crack. There-fore, properly installed expansion joints are extremely important and provide a controlled, mainte-nance-free crack location.

• Grout pours are time sensitive and a continuous pour is critical to project success. Using prop-erly placed and installed expan-sion joints offer additional control during the pour by creating pour sections in the event conditions become less than perfect — i.e., a mixer stops, a pump stops, or other unforeseen problems arise that cause an interruption to the pour.

Without properly placed expansion joints, there is no easy way to stop the pour and still have a successful job.

Once the expansion joint layout has been determined and marked on the foundation, the joints should be se-cured with a generous application of oil-resistant blue silicone and allowed to thoroughly dry before the equipment is placed.

The nature of the expansion joint material (typically a proprietary closed-cell foam) should allow the joint to compress under the weight of the equipment while it is being set without causing any disruption to the place-ment and leveling of the skid.

Preparing the skid to be placed on the foundation

With the foundation prepared and ready for the equipment to be placed,

attention will need to be given to the skid frame itself.

The skid frame and the steel that will be in contact with the grout must be clean, free of dirt, grout (if the equip-ment has been relocated to a new loca-tion), concrete, excessive rust or other contaminants or obstructions that would inhibit a good bonding surface.

Cleaning of the skid frame should be performed according to the skid manufacturer’s recommendations, by either sandblasting to white metal or cleaning with a rapidly dissolving sol-vent material such as acetone.

Similar to the discussion of stress concentration resulting from sharp corners, all corners on the skid must be rounded to a minimum of 0.375 in. (9.5 mm) radius to reduce the stress concentration in the grout.

This is also a good time to adjust the jackscrews to their preliminary set po-sitions and treat them with a de-bond-ing agent such as Anti-Seize or grease to assure they are adjustable after the grout has been placed. In the event an extended amount of time will pass be-fore the skid is to be grouted, wrapping the jackscrews with pipe insulation and duct tape may be a better option.

A fast and easy way to place the skid and save labor and time is to record the elevations of the jackscrew landing

OCTOBER 2013 66 COmpREssORtech2

FigurE 14 Photo shows a jackscrew landing pad with beveled edges.

FigurE 15 This shows a completed expansion joint.

CT271.indd 9 9/23/13 4:39 PM

pads, consider the depth of grout needed, and adjust the jack-screws to their exact set position prior to the equipment being placed on the foundation.

In most cases the skid can be placed in a “level” position without adjusting a single jackscrew once the equipment has been placed. Therefore, the jackscrews will not require the increased effort needed for adjustment under the dead weight of the skid.

Forming for the grout pourFabrication and installation of the forms is the next

step in the process. The placement method for the epoxy grout must be considered prior to the fabrication of forms. Additionally, the grout contractor needs to be aware of in-spection hole locations and may request the skid manu-facturer or the end user of the equipment for additional holes to be cut.

Inspection holes ensure placement of the grout is pro-ceeding as planned and help prevent pockets or areas where the grout contact with the equipment is not sufficient. When problems develop after the equipment is in operation, it is common practice to cut holes into the skid in order to in-spect the grout condition. The same effort should be made early in the process in order to prevent installation problems from occurring.

Inspection holes may often double as pour locations. However, if the pour plan is to place grout directly into the skid from the top, there must be holes available in every section of the skid to assure proper placement. There are two preferred placement methods that provide a superior grout installation.

• Head boxes (Figure 16) use the weight of the grout to produce head pressure that is used to push or place the material under the skid. Head boxes have limita-tions, depending on the viscosity of the grout that is being used.

A good epoxy grout under favorable temperature condi-tions will flow 15 to 18 ft. (4.6 to 5.5 m) with the use of a head box. As stated earlier, it is essential to use an epoxy

We Manufacture andRemanufacture the

World’s LargestCrankshafts

Ellwood Crankshaft GroupIrvine, PA, USA 16329

Hermitage, PA, USA 161481-800-247-1326

or 724-347-0250ecgsales@elwd.com

www.ellwoodcrankshaftgroup.com

We Manufacture andRemanufacture the

World’s LargestCrankshafts

Ellwood.qxp 1/27/10 11:51 AM Page 1

KIENEDIESEL ACCESSORIES, INC.

Telephone: 1-800-264-5950 Fax: 630-543-5953E-mail: info@kienediesel.com Website: www.kienediesel.com

KIENE INDICATOR VALVESFOR COMPRESSOR ANALYSIS

•• Large, Straight-Through flow path minimizes channel resonanceand maximizes accuracy.

•• Compact design is safe — no need for separate nipples oradapters.

•• Vent Valve safely relieves pressure prior to removing transducer.

•• 2000 PSI, 250° (F) capacity.

•• Quarter-turn for fast operation

Safety Locking Handle option is also available

THE CV-SERIES INDICATOR VALVES ARE DESIGNED SPECIFI-CALLY FOR COMPRESSOR ANALYSIS.

CALL NOW FOR INFORMATION.

FOR MAXIMUM ACCURACY, KIENE’S NEW FULL-OPENING CV-70 SERIES INDICATOR VALVES PROVIDE THESE FEATURES:

Kiene 1/4 ad 5/22/02 2:05 PM Page 1

OCTOBER 2013 67 COmpREssORtech2

continued on page 68

Figure 16 Head boxes push the grout under the skid.

CT271.indd 10 9/23/13 4:40 PM

grout that has good flow characteris-tics without reducing the amount of aggregate below the advertised tech-nical specifications of the product.

• Pumping grout under the equip-ment (Figure 17) is another ef-fective method for grouting skid-mounted equipment. Utilization of a grout pump allows a hose to be placed under the equipment and the epoxy grout to be placed ex-actly where it is needed.

Pumping is the preferred method

for grout installation when the equip-ment width exceeds 18 ft. (5.5 m) and when obstructions such as bottles or piping inhibit the ability to construct and place necessary head boxes.

The forms will need to be construct-ed and placed in a manner that allows sufficient room for placement of the grout. The best design for a grout cap avoids a wide shoulder between the skid frame and the outer limits of the foundation. Due to the extreme differ-ence between the modulus of elastic-

ity of concrete and that of epoxy grout, epoxy performs best when installed under a constant dead load.

When a wide hearth cannot be avoided, installation of pinning in the open areas is highly recommended to reduce the effects of edge lifting or curling cracks (Figure 18). Pinning should be at least a size four rebar secured by epoxy grout and should extend below the top course of rebar. For best results, the pinning should also be installed inside the limits of the outer course of rebar. An example of pinning and other proper forming technique is shown in Figure 19.

As with any foreign material that is in contact with the grout pour, the pinning should be rounded and smooth in order to minimize local stress. Properly placed edge pin-ning will increase the tensile strength of the concrete foundation, improve the bond between the two materials, and better resist cracking under the stresses that are created when the two substrates expand and contract at different rates.

Forms will be constructed of wood, be secured so that they will be ca-pable of resisting the forces imposed by the weight of the epoxy grout, and will require a watertight seal when in-stalled (Figures 18 and 19).

A high-quality silicone is the most effective way to prevent grout from leaking during the pour.

All forms that will be in contact with epoxy grout will need to be treated with two to three coats of a good qual-ity paste wax to break the bond be-tween the wood and epoxy grout.

When head boxes are used, they should be sealed in a way that will not allow any grout to escape prior to flowing under the skid. All corners of the forms should be chamfered in or-der to reduce localized stresses from forming and reduce the risk of stress related cracking.

Grout mixing and placementProper preparation and good plan-

ning are essential to the success of any project, and grout projects re-quire a great deal of preparation in order to arrive at success. Field con-

OCTOBER 2013 68 COmpREssORtech2

FiGure 17 A worker pumps grout under the equipment.

FiGure 18reinforced steel pinning is used in open areas.

CT271.indd 11 9/23/13 4:40 PM

ditions are frequently outside the required specifications for proper mixing and placement of epoxy grout. Epoxy grout is temperature sensitive and performs best when temperature conditions are between 65° and 90°F (18° and 32°C).

For this reason, before mixing any grout, it is the contrac-tor’s responsibility to make conditions as close to perfect as possible. Tenting and heating or cooling is often required in order to successfully grout the equipment in place.

Adequate time necessary to obtain preferred temperature conditions should be incorporated into the project schedule and the increased cost of heating or cooling will need to be incorporated into the project budget.

Epoxy grout is also time sensitive and the pot life of the epoxy grout being used must be taken into consideration during mixing and placement. A grout pour should always be planned as a swift and continuous process from start to finish. The contractor will need to have a sufficient amount of properly conditioned material at the pour loca-tion before the pour is started.

It is also important to have the right equipment necessary to mix the resin and hardener together in the buckets pro-vided by the manufacturer as well as a paddle-type mortar mixer to thoroughly mix the combined liquids together with the aggregate.

OCTOBER 2013 69 COmpREssORtech2

continued on page 70

Figure 19 Photo shows a chamfered skid form and rounded skid corner.

Recognized Leader

Innovator in State-of-the-ArtPipe Supports & Clamps Inventor of Flywheel Lock

Leaders in Field Machine WorkPioneers in Casting Rapair

PRODUCTS:n Pipe Supports & Clampsn Epoxy Groutn Anchor Boltsn Flywheel Locksn Temperature & Vibration Sensorsn Spark Plugs

SERVICES:n Field Machiningn Casting Repairn Crankshaft Machining n Machine Shopn Broken Bolt Removaln Frame Reinforcementn Alignment Services

918-252-7545www.r-f.cominfo@r-f.com

Tulsa, OK

ReynoldsFrench.indd 1 7/8/13 2:07 PM

CT271.indd 12 9/23/13 4:40 PM

Heinzmann GmbH & Co. KGAm Haselbach 1D-79677 Schönau/GermanyPhone: +49 7673 8208 - 0Fax: +49 7673 8208 - 188Email: info@heinzmann.de

HEINZMANN Contacts in North America

Subsidiaries

USAHeinzmann America, Inc.1305 Duff Drive, Unit 1AFort Collins, CO 80524Phone: +1-970-484-1863Email: info.usa@heinzmann.com

CanadaHeinzmann GmbH & Co. KG1013-14 AvenueWainwright, AB, T9W 1K5Phone: +1-780-231-2280Email: b.powers@heinzmann.com

Agents

USAKraft Power Corporation199 Wildwood Ave.Woburn, MA 01801-2024Toll free: +1-800-969-6121

Further offi ces:• Suwanee, GA

Phone: +1-800-394-0078 (Toll free)Email: GAinfo@kraftpower.com

• Gaylord, MIPhone: +1-866-713-2152 (Toll free)Email: MIinfo@kraftpower.com

• Charlotte, NCPhone: +1-704-504-3033Email: NCinfo@kraftpower.com

• Houston, TXPhone: +1-800-394-0078 (Toll free)Email: aschaub@kraftpower.com

• Massillon, OHPhone: +1-330-830-4158 Email: rmontgomery@kraftpower.com

• Pompton Plains, NJPhone: +1-800-221-3284 (Toll free)Email: NJinfo@kraftpower.com

• Syracuse, NYPhone: +1-877-349-4184 (Toll free)Email: NYinfo@kraftpower.com

• Sturtevant, WIPhone: +1-262-884-8666Email: WIinfo@kraftpower.com

CanadaAdvantage Governor & Controls Inc.1013-14 AvenueWainwright, AB, T9W 1K5Phone: +1-780-842-4248Email: sales@advantagegovernor.com

Wajax Power Systems2997 rue WattQuebec, QC G1X 3W1 Phone: +1-418-651-5371Email: PCusson@wajax.com

Heinzmann_ThrdVrt.indd 1 9/17/13 1:09 PM

OCTOBER 2013 70

The grout pour itself (Figure 20) is the most labor-intensive part of the grout project and will require several people dedicated to properly com-pleting the organized pour plan. The contractor will need to provide enough manpower trained in grouting proce-dures to have people dedicated at the mortar mixer, mixing the liquids, plac-ing the grout, and finishing. Before the pour starts, everyone should know their assignment and be comfortable performing their responsibilities.

It is also essential to have some-one assigned to overseeing the pour, performing such tasks as assuring the quantity of grout being used matches what was expected, checking weather conditions, and solving any potential problems that could arise. It is always a good idea to have a backup plan should a mixer or pump fail during the pour.

FinishingWhile the grout is being poured,

the curing process has already begun and finishing of the grout surface will need to be started while the pour is still in progress. During the polymer-ization process small air bubbles will rise to the surface of the grout.

Using a solvent that flashes off quickly, such as acetone, lacquer thin-ner or mineral spirits, will eliminate the bubbles and leave an aesthetically pleasing surface appearance. The grout manufacturer is the best refer-

Figure 20 This is a typical grout pour for a compressor package.

ence when determining what product will work best for finishing.

Once the grout has cured, the forms may be removed. The edges of the ep-oxy grout should be smoothed using an angle grinder with a grinding disc designed for use with masonry. Expan-sion joints may require additional work after the grout pour, including finishing with a permanent sealant. CT2

Geoff Anderson is president of Tech Trans-fer Inc., which specializes in the design and analysis of reciprocating compres-sor packages including pulsation, skids, piping, foundations and vibration. A pro-fessional engineer, he has conducted re-ciprocating compressor package design and field vibration analysis for 40 years. Contact him at: geoff.anderson@techtran-hou.com. Bob Rowan is a professional engineer and director of Robert L. Rowan & Associates Inc., a 60-year old firm ac-tive in development of technologies for equipment grouting, engineered repairs of compressor foundations and manufac-turer/supplier of anchor bolts, precision machinery support systems and epoxy grouting materials. Contact him at: rob-ert@rlrowan.com. Jeff Butler is a profes-sional engineer and cofounder of Eagle Compression LLC, which specializes in industrial foundation work, including re-moval and replacement (re-grout), foun-dation restoration and repair and industri-al skid grouting. Contact him at: jbutler@eaglecompression.com.

CT271.indd 13 9/23/13 4:41 PM

All components from one supplier

Precise ignition timing

Increased spark plug durability

We supply it all

PHLOX IINew Generation of Ignition Control

Speed & Load Control WastegateAir Fuel Ratio Control Knock Control

Gas Engine Management

PHLOX Ignition Control System for all engine sizes and fuel gases

On-board diagnostics

Up to 8, 12 and 16 cylinders

Master-Slave operation for up to 24 cylinders

Ignition Control

www.heinzmann.com

booth 922 booth 3945

Meet us at

and

Subsidiaries

USAHeinzmann America, Inc.1305 Duff Drive, Unit 1AFort Collins, CO 80524Phone: +1-970-484-1863Email: info.usa@heinzmann.com

CanadaHeinzmann GmbH & Co. KG1013-14 AvenueWainwright, AB, T9W 1K5Phone: +1-780-231-2280Email: b.powers@heinzmann.com

Agents

USAKraft Power Corporation199 Wildwood Ave.Woburn, MA 01801-2024Toll free: +1-800-969-6121

Further offi ces:• Suwanee, GA

Phone: +1-800-394-0078 (Toll free)Email: GAinfo@kraftpower.com

• Gaylord, MIPhone: +1-866-713-2152 (Toll free)Email: MIinfo@kraftpower.com

• Charlotte, NCPhone: +1-704-504-3033Email: NCinfo@kraftpower.com

• Houston, TXPhone: +1-800-394-0078 (Toll free)Email: aschaub@kraftpower.com

• Massillon, OHPhone: +1-330-830-4158 Email: rmontgomery@kraftpower.com

• Pompton Plains, NJPhone: +1-800-221-3284 (Toll free)Email: NJinfo@kraftpower.com

• Syracuse, NYPhone: +1-877-349-4184 (Toll free)Email: NYinfo@kraftpower.com

• Sturtevant, WIPhone: +1-262-884-8666Email: WIinfo@kraftpower.com

CanadaAdvantage Governor & Controls Inc.1013-14 AvenueWainwright, AB, T9W 1K5Phone: +1-780-842-4248Email: sales@advantagegovernor.com

Wajax Power Systems2997 rue WattQuebec, QC G1X 3W1 Phone: +1-418-651-5371Email: PCusson@wajax.com

Heinzmann_ThrdFull_Sprd.indd 2 9/17/13 1:10 PM

The new compression busi-ness unit of Siemens Energy, based in Duisburg, Germany,

has announced the sales of several compressor trains for large-scale air separation units (ASUs) under con-struction in China, Vietnam and India.

Large volumes of oxygen are re-quired for gasification purposes when natural gas and coal are converted into liquid products (fuels and chemicals).

The family of Siemens geared-type compressors has recently been ex-tended by the large STC-GC (geared-type compact) line, which uses a maximum number of standardized components in order to achieve short delivery times and reduced capital ex-penditures by keeping the efficiency

at a level comparable to customized geared-type machines.

The largest in this compressor line is an STC-GC (400), capable of han-dling an air flow of 14.1 MMcfh (400 x 103 m3/hr), which would fit to a 2200 tpd (2000 T/d) oxygen ASU plant. This machine is a single-flow, three-stage, main air compressor (MAC) with a compression ratio of 7.6.

Siemens has a tradition of supply-ing geared compressors to contractors specializing in ASU plants. The Ger-man company has developed geared compressors for several applications and more than 2000 units are in op-eration worldwide. It invented the mul-tishaft, geared-type compressor and introduced it to the market in 1948.

It also has built the largest machines of this concept, capable of flows ex- ceeding 20.1 MMcfh (570 x 103 m3/hr). Savings in space and weight for the recently developed compressors is achieved with the introduction of a high-performance, 3-D impeller family featuring high flow coefficient and high efficiency. More than 100 of these im-pellers are in service.

Geared-type compressors were mainly foreseen for motor-driven equipment, which in the past domi-nated the air separation business. Now, mainly for gasification applica-tions, steam turbines are required in the corresponding air separation plants due to the availability of steam caused by exothermal processes.

Isothermal turbocompressorThe Siemens answer to these re-

vised market requirements was the newly developed STC-SI compres-sor. This is an isothermal inline com-pressor combining the advantages of the well-known geared-type ma-chine with the single-shaft concept fully adjusted to the requirements of a steam turbine drive.

The first impeller is mounted in an overhung position before the first main bearing so as to feature an axial in-let flow controlled by a variable inlet guide vane. The impeller is mounted on the shaft end with a Hirth-type con-nection that allows removal and reas-sembly on the shaft without need for balancing operations.

Before being fed to the second-stage impeller, the compressed air flow is routed through a set of four coolers, 90° staggered and mounted in an X configuration directly onto the compressor casing.

The same cooling configuration en-sures air cooling between the second and third compressor stages. When required, an external cooler can be supplied after compressor discharge.

The Large ASU Race > Siemens compressor portfolio serves a broad market

By RoBERTo CHELLINI

n The Siemens STC-GC compressor uses a maximum number of standardized components.

OCTOBER 2013 72 COmpREssORtech2

CT261.indd 1 9/23/13 12:01 PM

The X-mounted coolers can easily be disassembled from the compres-sor casing, for transportation and/or maintenance, by means of a specially designed tool.

The cooler bundles can remain in the integrated shell for transportation purposes, which reduces the assembly time substantially. The coolers feature condensed water extraction passages and automatic evacuation systems.

To reduce transportation costs, spe-cialized companies make the coolers, in Germany or locally, under Siemens supervision and quality control. The cooler design is flexible and can be adapted to each specified requirement in terms of material and performance.

The STC-SI compressors have the benefit of an isothermal compression equal to the geared-type compressors by interstage cooling and the addition-al advantage of eliminating the losses entailed by the gear system of geared compressors, thus allowing a power saving estimated at 2 to 3%.

The high flow coefficient of the new impeller family allow the use of impellers for flows once handled only by axial stages. Siemens still makes axial/radial compressors (STC-SR) for very large flows. The new impel-ler family has just moved to the right the shifting point between radial and axial/radial compressors.

The use of radial stages instead of axial makes the compressor more compact and less expensive to manu-facture. Compared to an axial solution, a radial compressor can be equipped with more cooling stages, which fulfill

the demands of the industry to reduce the power requirement.

Train solutionsSiemens offers comprehensive

compressor train technology, thus its product portfolio includes the driver (electric motor or steam turbine) and the booster compressor (BAC), also of the geared type. The number of BAC stages depends on the air separation

OCTOBER 2013 73 COmpREssORtech2

n The Siemens isothermal STC-SI compressor combines the advantages of geared and single-shaft machines.

process selected (low- or high-pressure).The driver is usually an electric mo-

tor for smaller units and a steam tur-bine for larger plants, with some over-lapping in the mid class.

The advantage of having all compres-sor train components in-house is clearly visible in the design of the STC-SI fam-ily. Each compressor size has been de-signed so that its rotating speed exactly matches the corresponding steam tur-bine size so as to maximize efficiency of both compressor and turbine.

Train ordersSiemens said 20 large-geared com-

pressor trains have been sold since January 2012, one for a steel plant in Vietnam, six via Air Liquide for a CTL Sinopec plant in China, 10 to Linde for GTL lines in India and three to Air Liquide for the Urumuqi CTL plant in the Xinjiang Uyghur Autonomous Region, China.

Also, Linde has ordered three com-pressor trains with axial/radial MAC for the Yili Yitai plant of Yitai Coal Co. in Inner Mongolia, China. CT2

EXCESSIVE NOISE?

withINSULTECHACOUSTICBLANKETINSULATIONA removable, reusable engineered system.30” Service Connection Piping with a 13 DBA reduction in

Sound Pressure Level

INSULTECH’S unique composite design construction can maximize acoustic per-formance through both absorption and reflection. Utilizing CAD/CNC Technology, INSULTECH can be shaped and custom fit to numerous surfaces, equipment and piping schemes. Shannon Enterprises offers noise metering services with before and after sound results. INSULTECH can show reductions of 4-20 DBA.

INSULTECH

ACOUSTIC BlAnkeT InSUlATIOn

ENTERPRISES OF W.N.Y. INC.

Telephone: 716-693-7954Fax: 716-693-1647Representative Inquiries Welcome

INSULTECH®

Shannon Enterprises of W.N.Y., Inc.75 Main St., N. Tonawanda, NY 14120www.blanket-insulation.comEmail: info@blanket-insulation.com

HELP SOLVE INDUSTRIAL NOISE PROBLEMS AT THE SOURCE

19134_ADS_4.25x4.875_Rev3.indd 1 1/26/09 1:29:58 PMShannon.indd 1 9/19/13 3:05 PM

CT261.indd 2 9/23/13 12:01 PM

Claudio Vegline is customer support engineer for Dott. Ing. Mario Cozzani S.r.l. Contact him at: claudiovaglini@cozzani.com. Andrea Raggi is a research and development engineer for Cozzani. Contact her at: andrearaggi@cozzani.com. Enzo Giacomelli is a consultant for Cozzani. Contact him at: enzo.giacomelli@hotmail.com.

Stepless Capacity Control For Recips >

The increasing requests from end users to reduce energy consumption and improve reliability have required great ef-forts in the design and development of reciprocating com-pressor components, particularly the valves.

Flow control systems that act directly on reciprocating compressor valves have been undergoing continuing re-search. They play a major role and related innovations are possible by technological evolutions, advanced calculation systems, new materials and electronic components.

In order to assure a quick, reliable and accurate step-less capacity control, Dott. Ing. Mario Cozzani S.r.l. devel-oped and patented its own system (FluxtoFlow). Because of special electromechanical actuators, this system is able to control the suction valve shutter position during each com-pression cycle. The results of these applications on vari-ous compressors show excellent performance with the new stepless control system, particularly in energy savings.

Capacity controlThe capacity control allows pressures or flows to be

adapted to the process requirements and is normally real-ized with: on/off operation; motor speed variation; bypass between discharge and suction; suction throttling; cylinder unloading; volumetric control by fixed or variable clearance pockets; and reverse capacity control.

The most used is the cylinder unloading, with (pneumat-ic) actuators on suction shutters with finger unloaders keep-ing them in an open position. In a double-acting cylinder, one or both ends can be unloaded with approximately 50 or 100% reduced flow. The cylinder unloading, combined with clearance pockets, allows additional control steps.

With the evolution in electronics and software, stepless control devices have been developed to face the demand for energy saving with variable-speed drivers (with inverter) and reverse flow capacity control systems. The latter is realized by keeping the suction valve open beyond bottom dead cen-ter, so that gas entering the cylinder flows back through the suction valve as long as it remains open at any cycle (Figure 1). These devices have been generally of the hydraulic type.

n Figure 1. Graphs show the PV cycle with reverse flow.

The complex control of the position has been improved by electronic systems able to activate the valves and guar-antee the required precision and repeatability, but requiring advanced calculation to develop the appropriate algorithms for the control.

The selection of a capacity control system involves engi-neering analyses and preliminary studies for technical and economic return evaluation. As this system is important for the operation of the compressors, it should be analyzed in cooperation with the machine manufacturers.

FluxtoFlowThe system developed and patented by Cozzani is made

with the following components: electric actuators installed on suction valve covers to control the position of their shutters; system control unit (SCU); actuator control units (ACUs); sensors for the measurements required by the sys-tem. The diagram of the suction valve’s actuator control can be represented as in Figure 2.

TECHcorner

OCTOBER 2013 74 COmpREssORtech2

Cozzani’s FluxtoFlow system controls suction valve shutter positions

By ClAUDIo VeglIne, AnDreA rAggI

AnD enzo gIACoMellI

CT265.indd 1 9/23/13 12:04 PM

OCTOBER 2013 75 COmpREssORtech2

n Figure 2. The diagram illustrates the capacity control system.

The SCU is used to interface the compressor with the ACUs (Figure 2).

The SCU receives digital signals from the compressor system (position signal of crankshaft), to register the exact position of the piston during each cycle and the input signal is used for the capacity control to set the actuator control parameters. Consequently, the SCU controls the suction valves during the entire compression cycle.

The development of this unit required customized soft-ware to manage all the working phases including start-up, full load, capacity control and shutdown.

The ACUs, receiving information from the SCU on the valve opening instant and its holding time, convert the infor-

mation in voltages across the magnetic windings that deter-mine the positioning of the actuators.

Every ACU is made with two main parts: the control that includes all the components for managing the signals and the communication interfaces; and the power components for the voltage control of the windings and to measure of the currents.

The main feature of the actuator provides the name “Flux To Flow” to the system; the magnetic flux controls the compressor flow.

Electromechanical actuationThe new actuator is conceptually innovative as it is com-

pletely electric and has been entirely designed by Cozzani. This actuator (Figure 3) has a central sliding part, called an armature, two electromagnets located at the opposite sides of the armature, with the objective to move it linearly and

to move the lower rod that acts on the finger, and two springs located at the opposite sides of the arma-ture to accelerate and decelerate the actuator moving parts.

n Figure 3. This is a 3-D model of the actuator.

continued on page 76

Improve reliability with super-tough ceramic bearings from SKFSKF rolling bearings made with corrosion resistant steel, ceramic rolling elements and PEEK high performance cages are a game-changer for oil-flooded single and twin screw compressors.

• First sour gas pilot in 2004, 10 times the service life• Used in SSC NACE/ISO, region 3 inlet conditions• 40 mol% H2S and 35 mol% CO2 combined

• 100 mol% H2S and CO2 combined

• Hydrogen-rich gases Learn more at www.skf.com/sourgas.

Sour gas eats bearings.And profits.

The Power of Knowledge Engineering

SKF.indd 1 6/17/13 9:48 AM

CT265.indd 2 9/23/13 12:04 PM

Cozzani has developed and patented a sophisticated control algorithm, dealing with nonlinearity in the magnetic force and with variation of the gas force, depending on the different running conditions of the compressor.

ApplicationsThe system has been installed in some single and mul-

tistage compressors (Figure 5) in order to verify the cor-rectness of operation in different operating conditions.

n Figure 5. This compressor is fitted with Fluxto-Flow devices.

All the suction valves were equipped with actuators (Figure 6) to exploit the capability of the system and for lower energy consumption during the valve crossing the valve passages.

The decision to use an actuation on each valve is more important for high molecular weight gases, while for H2 rich gases the result could be easily obtainable with a lower number of suction valves subject to the un-loading procedure.

n Figure 6. This close-up photo shows the actuator on the compressor.

A proximity sensor has to be installed on the com-pressor to determinate the top dead center as reference to make the SCU generate the starting signals for the ACUs, depending on the compressor geometrical data.

A closed-loop pressure controller has been imple-mented in the SCU. External controller can be interfaced with the SCU. The system is very flexible and can be applied and added to any existing operating plant with a suitable interface (Figure 7).

OCTOBER 2013 76 COmpREssORtech2

Gaskets and recycle gas connections are in the low-er part. Connectors and the sensor to measure the rod position are in the upper part. The device has a high dynamic performance able to respond positively to the strict times required by the various phases of the com-pression cycle. Without saturation, the force produced by the electromagnets is proportional to the square of the current, but decreases with the air gap between arma-ture and electromagnet.

A typical actuator working cycle begins by energizing the upper electromagnet. The force generated moves the armature upwards. The displacement creates the dif-ference between the spring forces that in turn accelerate the armature when the voltage across the upper winding is reduced to zero. In the meantime, the lower electro-magnet is energized to establish the flux to attract the armature down.

As soon as the armature moves closer to the lower elec-tromagnet, it is caught and kept in position for the set time (Figure 4). Also in this phase, a difference in the spring forc-es is produced allowing an upward movement.

n Figure 4. Drawings show the electromechanical actuation.

Springs are important, as they provide the large iner-tial power to accelerate the armature at the beginning of its stroke and then absorb the inertial power to decelerate when it approaches the electromagnet. As the potential en-ergy is stored in the springs instead of being dissipated, the inertial power is regenerative.

Another characteristic of the system is the nonlinear-ity of the force-displacement relation. For this reason, the current required to hold the armature in contact with the electromagnet is low. Since this system is unstable in the equilibrium positions close to the electromagnets, special control methodologies are required to: limit the armature impact velocity during the landing phase, as high velocities produce unacceptable noise; ensure a transition time between upper and lower positions com-patible with the performance demands; and guarantee a high holding force when the air gap is equal to zero (forces necessary to keep the suction valve open during the reverse flow phase).

CT265.indd 3 9/23/13 12:04 PM

OCTOBER 2013 77 COmpREssORtech2

Housings, cylinders, connecting rods …

Let our skilled craftsmen get to work for you!

Visit our website at www.HahnMfg.com

precision boring, milling, drilling, tapping and grinding on ferrous and non ferrous

material up to 30,000 lbs.

Certified Quality Management System

ISO 9001:2008

Hahn_AugSept.indd 1 8/19/13 10:01 AM

The operation confirmed the SCU’s capability to con-trol the compressor capacity adapting it to the plant requirements.

The operation with different flow rates has been checked in order to verify the relation with the power consumption (Figure 8), indicating the expected energy saving when running at reduced operation. The devices (Figure 7), act-ing on the suction valves at every compression cycle, have demonstrated extreme precision on the control of the posi-tion, ensuring a high versatility in managing the required compressor needs (like the control of throughput with con-stant discharge pressure, suction or inter-stage pressure control, etc.).

n Figure 8. This graph shows power consumption versus flow rate.

The system can be installed in refineries and petrochemi-cal plants. The certification of the system for use in poten-tially explosive atmospheres can be obtained in compliance with ATEX codes.

ConclusionsThe capacity control obtained by a new electrome-

chanical actuator has exhibited a high dynamic per-formance, necessary in different phases of the com-pression cycle, in compressors running under various operating conditions.

Installation time is very short and the operation is reliable in all requested capacity control needs. The energy sav-ing obtained gives further advantage during the part load operation required by the production. Maintenance of the system is very simple because it involves only electrome-chanical components. CT2

n Figure 7. This diagram shows the system architecture.

Einstruments.indd 1 3/7/13 9:49 AM

CT265.indd 4 9/24/13 4:13 PM

SummitIndustrial Products

Problem Solving Synthetic Lubricants

Lubricant Dilution?Lubricants used in oil flooded compressors willtend to absorb the gas being compressed.This is especially true for hydrocarbon gases withhigh BTU content. This absorption results in athinning of the oil ’s viscosity and compromisesits ability to properly lubricate bearings. The effect is known as dilution. To combat thisproblem, Summit has developed specializedequipment that measures a lubricant ’s changein viscosity under gas stream and compressorconditions. We’re able to use that informationto predict the dilution effect a gas stream willhave on different lubricant base stocks andchoose a lubricant that will meet your specific OEM compressor specifications.

Prevent dilution and protect your compressor

800.749.5823www.klsummit.com

Dilution Ad_Layout 1 8/13/2013 4:45 PM Page 1

Summit.indd 1 8/15/13 9:55 AM

Engine, System ControlsThe latest catalog from Governors A m e r i c a n Corp. in-c ludes al l p r o d u c t s and acces-sories for engine con-trol, such as a c t u a t o r s ,

speed controllers, magnetic speed pickups, generator control, monitoring, J1939 data displays, and gaseous fuel control and ignition systems.

www.governors-america.com

Finishing ProductsRex-Cut Abrasives, of Fall River, Massachusetts, has published its 2013-2014 product catalog, which features nonwoven cotton fiber abrasive grinding wheels, cutoff wheels, mounted points, and other types of grinding, blending, deburring, and finish-ing products. The catalog also includes usage tips; charts with sizes, shapes and specifications; and QR codes to video demonstrations.

www.rex-cut.com

Catalytic SilencersDCL Inter-national has pub l i shed literature on its catalytic silencers for s tat ionary engines 500 hp (373 kW) and up. En-gine types include rich-

and lean-burn natural gas, as well as diesel and biofuels. The silencers also help new and old power plants meet high emissions standards.

www.dcl-inc.com

Combustion InstrumentationIMI Sensors released a combustion d y n a m i c s instrumen-tation bro-chure that h igh l igh ts application-s p e c i f i c products for monitoring

gas turbines. The brochure identifies three applications for detecting and measuring combustion dynamics in gas turbines.

www.imi-sensors.com

lItEraturE

OCTOBER 2013 78 COmpREssORtech2

CT_LIT_Oct.indd 1 9/23/13 3:42 PM

TurboCool CouplingA brochure from Voith p r o v i d e s i n f o r m a -tion on its TurboCool c o u p l i n g , d e s i g n e d to control the speed of the fan in

a compressor station’s cooling system. The brochure contains testing results, energy saving data, information on noise emissions and operating cost reductions.

www.voithturbo.com/startup-components

Lubrication System ComponentsAriel Corp. has pub-lished lit-erature on the compo-nents for its force-feed lubrication s y s t e m . The compo-nents listed include in-

jection check valves, rupture discs, re-settable pin indicators, balance valves, pressure gauges, force-feed lubricator pumps and oil traps.

www.arielcorp.com

Product Selection Guide M y e r s & C o . h a s r e l e a s e d i t s p r o d -uct selec-tion guide. Products in the guide i n c l u d e tube fittings, g a u g e valves, pipe

clamps, air and gas filters, air pressure regulators, sensors, cylinders, tubing, temperature and pressure transmitters and diaphragm valves.

www.myerscoinc.com

CatalystJohnson Matthey has developed a base-metal Halo-cat SC29 catalyst designed to reduce up to 99% of VOC and toxic organic compounds from PTA (puri-fied terephthalic acid) manufacturing plants. Halocat SC29 catalyst targets pollutants in PTA plant ex-haust streams, including carbon monoxide, methyl bromide, acetic acid, benzene, toluene, alcohols, acetates, formates and xylenes.

www.mathey.com

LiTeraTure

800-227-0729 • www.testo350.com

testo 340. The Ultimate Engine Tuner.• Up to four sensors for complete analysis• Highest measurement ranges for NOx and CO• Best for rich & lean burn combustion tuning• Simple to use and built for the field

SPECIAL LIMITED TIME OFFERPurchase a testo 340 or testo 350 and receive

a FREE Veto Tech Series Tool Bag!

Offer good from 9/1/13-12/31/13.

O2 • CO • NO NO2 • NOx

(NOx)

800-227-0729 testo350.com

free with purchase of the testo 340 or testo 350

testo340-half-island.indd 4 9/18/2013 12:59:20 PMTesto.indd 1 9/18/13 1:25 PM

OCTOBER 2013 79 COmpREssORtech2

CT_LIT_Oct.indd 2 9/24/13 4:16 PM

All the authors are turbomachinery engineers with the Petrobras E&P Rio de Janeiro operations unit. Fabio de Norman et d’Audenhove is the leading mechanical engineer in the group responsible for technical support to existing turbomachinery operations. He has a mechanical engineering degree from Universidade Federal do Rio de Janeiro. Contact him at: fnorman@petrobras.com.br. Andre Varella Guedes is responsible for technical support and troubleshooting with the existing turbomachinery fleet in upstream oil and gas services. He holds bachelor’s and master’s mechanical engineering degrees from Federal University of Rio de Janeiro. Contact him at: avarella@petrobras.com.br. Michel Stathakis Neto is a member of the engineering group supporting existing turbomachinery operations. He has a bachelor’s degree in electronic engineering and a master of technology degree, both from Centro Federal de Educação Tecnológica. Contact him at: Michel.neto@petrobras.com.br. Bruno da Silva Marques specializes on performance issues in the group supporting turbomachinery operations. He has bachelor’s and master’s degrees in mechanical engineering from Univer-sidade Federal do Rio de Janeiro. Contact him at: brunomarques@petrobras.com.br.

Fixed-Speed Compressor Drivers For Offshore Platforms >

Editor’s Note: The authors would like to thank the em-ployees of the Petrobras turbomachinery maintenance teams, engineering group and research center who helped solve the issues presented in this article. This article is based on a paper presented at the 41st Turbomachinery Symposium in Houston on Sept. 21-27, 2012.

The first production platforms in Petrobras’ operational unit in Rio de Janeiro used variable-speed drivers for their main gas compressors: gas turbines in one platform and electric motors with variable frequency drivers (VFDs) on the other three platforms.

The use of fixed-speed electric motors to drive the main compressors began to be used in upstream projects begin-ning in 2002, with the first two platforms starting production in 2008 and 2009. This new configuration of the main com-pression system brought new challenges and a new philos-ophy for its operation and control, along with a simplification of the compression module.

The problems faced in the first years of operation on these

two units led to this article. Historically, the three-compressor stage train, in two casings, was powered by a single driver. In this new configuration for the main compressor system, the previous single three-stage train is divided into two compres-sor trains, each driven by its own electric motor, allowing great-er operational flexibility: a low-pressure compressor can be operated paired with any of the high-pressure compressors.

This simplification and increased flexibility of the main com-pression has taken its toll. The fixed-speed compressors and the suction throttling capacity control don’t have the same op-erational flexibility that variable-speed compressors do. The equipment limits, either in available head or available power, are more easily achieved with changing operational conditions in comparison to the design conditions. These deviations are quite common and have a wide range of causes, from opera-tional necessity to reservoir uncertainties in the design phase.

This article will show that the successful use of fixed-speed electric motors as compressor drivers in new projects depends largely on the reduction of reservoir uncertainties, a better assessment on the sizing of the driver during the design phase and new control strategies, such as the imple-mentation of a control loop for electric motor current.

HistoryThe selection of the technology used for the compressor-

driver pair takes into account various technical and eco-nomic factors. Some technical factors typically taken into account are the type of vessel where the compression system will be installed (floating production storage and offloading units or semi-submersible platforms), the opera-tional envelope, the required compression power, the asso-ciated control strategy, the weight and occupied area of the equipment and arrangement of the electrical system.

TECHcorner

They can simplify projects that have little variation in the gas flow

OCTOBER 2013 80 COmpREssORtech2

By FaBIo De NoRmaN eT D’auDeNHoVe, aNDRe VaRella GueDeS,

mIcHel STaTHakIS NeTo aND BRuNo Da SIlVa maRqueS

continued on page 82

n One of the Petrobras production units with fixed-speed electric motor compressor drives. The first two platforms with this applica-tion started production in 2008 and 2009.

cT258.indd 1 9/23/13 11:06 am

REAGAN EQUIPMENT CO., INC.A leading provider for parts, service, mechanical drivers and leased compression to include parts and repair of integral and separable compression, engines, pumps and turbines in the oil and gas, petrochemical, refining and gas transmission industries reaching across the U.S. and abroad from several locations.

AMERICAN WARRIOR, INC.One of the leaders in gas compression and the leader in CO2 compression, American Warrior has built a reputation as one of the leading packagers in the United States. Using conservatively rated industry recognized components; the design of each unit is engineered for durability and ease of service. The American Warrior brand is well known for either repackaging your existing unit or building new to your specifications to include creating the specifications for you if desired.

KILO-PAKWhile originally designed specific to the marine industry, Kilo-Pak has grown throughout the years to become the Reagan brand of engineered custom generator packages. Whether a standard package or a high spec custom is required the Kilo-Pak name means quality.

Power & Compression

The leaders in compression and power generation have come together to better serve the industry and bring a new standard in quality and stability.

Introducing the new

Power & Compression

Our core name has changed, but our philosophy remains the same and we’ve been building on this tradition since 1946.

Reagan Power & Compression 11 locations across Louisiana, Mississippi, Colorado, Texas, Kentucky and Florida.www.reaganpower.com • Parts, Service & Leased Compression 800.264.7767 • Manufacturing 800.235.9142

Reagan.indd 1 2/19/13 12:28 PM

OCTOBER 2013 82 COmpREssORtech2

The economic factors include the investment costs and operational costs. Operational costs account for spending in the entire life cycle of the unit (typically 25 to 30 years of operation), including energy, consumables, maintenance costs and, with greater importance, the availability of equip-ment. Each arrangement alternative will give the compres-sion system a different reliability and availability.

For the compressor, from a technical standpoint, the flow rates and discharge pressures typically demanded for pro-duction gas movement in offshore units typically lead to the selection of multistage centrifugal compressors with inter-stage cooling, liquid knockout between stages and contami-nants (such as CO2, H2S and water) removal plants.

The driver selection, taking into account the above pa-rameters, can be categorized according to the associated control strategy, divided into two major groups: variable speed compressors and fixed-speed compressors.

Variable-speed compressorsFor the compressor, speed variation is the most efficient

control strategy from both the energy consumption and op-erational flexibility points of view. From the driver viewpoint, however, the speed variation becomes a complicating fac-tor, due to the amount of required power and the size of the equipment involved, demanding more elaborate devices to vary the speed in a fast, reliable and controlled fashion. Typical devices used for this purpose in offshore gas com-pressors are gas turbines, variable-frequency drivers and hydraulic variable-speed drivers.

Gas turbine-driven compressorsThis configuration was historically used in the Campos

Basin projects prior to 2002. Gas turbines are well-proven technology in the offshore environment and have an inherent capacity for speed variation within the range required by cen-trifugal compressors. Typically, light industrial or aeroderiva-tive gas turbines are used.

As advantages of this driver, we have electric power be-ing used only for relatively small auxiliary loads, leading to a significantly reduced power generation system and asso-ciated electrical panels. A wide range of gas turbines with rated power up to 40,200 hp (30 MW) ISO is available with extensive operational experience.

As disadvantages, these devices are heavy and take up greater area when the auxiliary systems are taken into ac-count. They also present performance and integrity degrada-tion over time, requiring periodic interventions for preventive maintenance and have a significant influence from ambient conditions, leading to the need of oversizing the driver.

VFD-driven compressorsThis technology gained strength with developments in

power electronic devices and has different architectures de-pending on model and manufacturer. Despite their differences, these devices have a similar basic working principle: speed variation of the electric motor by variation on the frequency

of the voltage available to the motor. This is achieved by the use of power electronic devices, generically called thyristors, which function as switches controlling the rate of voltage puls-es delayed from the original ac source by a transformer.

This device has no moving mechanical parts to wear and shows good controllability, acting directly on the motor. Ad-ditionally, it presents a smooth start-up, reducing the impact of starting currents on the electrical system.

However, this arrangement requires much electric power, heavily impacting the size of the electrical system and lead-ing to a centralized power generation. Due to the size of the equipment, it requires greater sheltered area, ventilated or refrigerated for panels and transformers, resulting in great difficulty when the movement of components such as coils and transformers for maintenance is needed.

Depending on the configuration, it still requires harmon-ic filters and has a history of unforeseen failures to criti-cal components (thyristors, cells, coils, and transformers) during operation.

Compressors with fixed-speed electric motors and hydraulic variable-speed drives

This technology, although not new, has no history of ap-plication in offshore units in Brazil and will be used in the first platforms of the pre-salt area development.

This device, which replaces the gearbox, is approximate-ly 30% bigger than a traditional gearbox and uses an induc-tion electric motor with fixed speed. It varies the compres-sor speed changing the degree of hydraulic coupling in a torque converter, similar to torque converters in automotive hydraulic transmission.

As advantages, this system achieves reduced starting torques by reducing the hydraulic coupling, helping to re-duce the motor starting time and its impact on the electrical system, and it has the lowest total area requirement among the variable-speed options. It has a high reliability and avail-ability, in onshore applications, and, despite using moving mechanical parts, has low maintenance and operation costs.

Besides having no historical data in offshore applications, this arrangement also has the disadvantage of requiring a large centralized power generation system.

Adopting fixed-speed, electric motor-driven compressorsThe adoption of fixed-speed electric motors as drivers for

large gas compressors implies a simplification of the compres-sion system, with the replacement of variable-speed drivers (GTs, VFDs or HSDs) by suction throttling valves as the ca-pacity control strategy.

This change has brought a great increase in the system reliability, due to the failure history with long periods of re-pair of VFDs and their transformers, along with significant reduction in the area and weight required by the compres-sion system. This change also brought some disadvantages and the need of special attention to some details, especially in the design phase, which will be discussed later.

continued on page 84

CT258.indd 2 9/23/13 11:06 AM

Find out how to ignite your engine at…www.fwmurphy.com/intellispark-ct2Phone 918-317-2627 Visit us at Booth #718

Maximize the Performanceof your Spark-Ignited Natural Gas EngineMaximize the Performanceof your Spark-Ignited Natural Gas Engine

Ensure the health of your spark-ignited

natural gas engine with Murphy’s IntelliSpark

ignition controller and components.

True primary and secondary diagnostics provide

users with an intelligent view of engine operation,

while increased programming capabilities give

you ultimate control. The IntelliSpark systems

feature microprocessor, capacitive discharge

functionality for any application that requires a

cost-effective operation.

Keep the spark going in your engine by

running Murphy’s Engine Integrated Control

System (EICS). EICS utilizes IntelliSpark technology

to provide integrated spark and diagnostic

capabilities as part of a comprehensive Engine

Management solution.

Intelligent Ignition Control System

with Murphy’s new

1311251 5-13

Murphy_Intellispark.indd 1 9/17/13 10:06 AM

OCTOBER 2013 84 COmpREssORtech2

The use of electric motors with fixed speed led to doubts regarding its impact on the platform electrical system. Typi-cally, platforms in the Rio de Janeiro Operational Unit use compressors with two casings and nominal compression ratio and flow of 25:1 and 71 x 106 scfd (2 x 106 Nm3/d), which leads to a power of compression in the range of 13,410 to 16,092 hp (10 to 12 MW), and up to 22,400 hp (16.7 MW) in one unit using 106 x 106 scfd (3 x 106 Nm3/d) compressors. These two casings may be driven by a single or by two separate electric motors.

The adoption of compressor trains, driven by a single direct-starting electric motor, leads to special care being needed with respect to the electrical system of the platform, such as the selection of motors with low starting current to prevent big drops in the electrical system voltage and the need for the operation of four 21,188 hp (15.8 MW) gas turbine generator sets for the electric motor start up.

Because of the uncertainties with respect to these points, meaning, whether or not to perform direct starts in electric motors of this size in an isolated electrical system, in the first platforms with fixed-speed compressors Petrobas ad-opted a division in the compression system in two modules with the use of an intermediate header and one electric mo-tor for each compressor casing.

As a further disadvantage, the adoption of a single elec-tric motor to drive all the compressor casings leads to the selection of a large electric motor, making it extremely dif-ficult to be moved for repair in the event of a failure.

Some recent projects kept the two modules arrangement, but, rather than having an intermediate header, process plants such as dehydrating (glycol) and CO2 removal (amine) lies between them. On another unit, compression train ar-rangement with a single direct starting driver for all casings was selected, in this case with a 21,188 hp (15.8 MW) electric motor. These units described above are not yet in operation.

The split of the compression modules in two has advantag-es such as increasing the reliability of the system, by allowing operation of the low pressure and high pressure compres-sors in any arrangement (for example, operating LP-A with HP-C), and the usage of smaller motors, easing the move-ment of these components during any maintenance.

The adoption of an arrangement with an intermediary head-er results, however, in a dilemma with respect to the arrange-ment of the various compression stages on the different mod-ules. On all platforms in the Rio de Janeiro Operational Unit, as well as many others in Campos Basin, three compression stages (sections) are used, being usual for the first casing to contain two compression stages in back-to-back arrangement and another straight-through casing to contain the third stage.

This arrangement, when compared with the arrangement in which the first casing as a single-section, straight-through configuration and the last two stages are in another back-to-back casing, minimizes internal leakages between stag-es (because of the smaller pressure difference between the units), increasing the efficiency of the compressor.

However, the best balance of power requirements be-

tween the two casings is achieved by the second arrange-ment, allowing the selection of identical and interchange-able motors as drivers for each casing.

The use of identical electric motors has proved extremely valuable when it was needed to carry out a recall on all electric motors on one of the platforms. In this case it was possible to repair the motors in sequence while keeping only one LP compressor (with capacity slightly larger than the HP compressor) unavailable, thus minimizing the com-pression capacity loss.

On the other hand, the adoption of a straight-through cas-ing for the first compression stage and a back-to-back casing for the last two stages, results in higher suction pressures in the second and third stages. Depending on the concentration of CO2 in the compressed gas, this higher pressure may lead to or aggravate corrosion of carbon steel (function of the CO2 partial pressure and gas flow velocity), as occurred in an-other platform. In these cases, special care is needed in the design phase concerning the materials selection, especially for the suction region of each compression stage.

Issues and limitations with the fixed-speed configurationUsing fixed-speed electric motor driven compressors,

when compared with GT- or VFD-driven compressors, is a configuration option that is less adaptable to deviations in the operating conditions originally specified in the compres-sor selection phase.

Despite the gains from system simplification, the success-ful application of this driver option depends on the reduction of the uncertainties on the design parameters, especially the composition of the gas to be moved and pressures required.

Electric motor overloadIn the Rio de Janeiro Operational Unit, a major challenge

faced by the first two units operating with fixed-speed electric motors was the recurring events of compressor electric motor overload, which occurred largely due to the significant differ-ence between the design conditions of the compressor and its operating conditions, as required by the production plant.

The compressors in the first three platforms operating fixed-speed compressors were specified from a single oper-ational point. The choice of this rated point, for each unit, was made based in the foreseen maximum discharge pressure requirement to ensure gas lift and gas export throughout the life of the platform. The selection criteria of the driver, as stat-ed in the API Standard 617 (2002), ensures that the selected electric motor has an additional power margin of at least 10% over the highest required power among the specified condi-tions, in order to accommodate possible variations in process conditions and in the compressed gas composition.

However, the operating conditions established for these projects does not match the point of maximum power de-mand in the compressor operational range. In practice, the actual required discharge pressure to perform gas lift and gas exportation was lower than the design case,

continued on page 86

CT258.indd 3 9/23/13 11:07 AM

New Patented glass filled polymer insulator provides 30% greater dielectric strength and has a maximum service temperature over 50% higher than competitive OEM products!!!

• Impervious to corona damage• Eliminates dielectric failure• Resistorized models available

NEW PATENTED BLACKJACK™Spark Plug Extensions & Leads Last Longer & Cost Less

See BG’s online catalog for complete information on extensions & cable products, connectors, spark plugs, turbine leads, and service equipment including coil and primary testers, firing indicators, timing lights and tools.

IGNITION PRODUCTSThe BG Service Co., Inc

1400 Alabama Avenue West Palm Beach, Florida 33401(561) 659-1471 • Fax (561) 659-1728

Email: sales@bgservice.com

www.bgservice.com

BG_Services.indd 1 2/21/13 2:32 PM

OCTOBER 2013 86 COmpREssORtech2

resulting in a different operating condition than originally provided (Figure 1).

n Figure 1: These schematics show how an operating point that is different from the rated point can lead to a power demand above the electric driver rated power, causing overload.

In general, centrifugal compressors tend to demand more power with higher flow rates and with lower pressure ratios required by the process. In this case of increased power demand, the power margin in the electric motor is reduced to less than 10%, being often insufficient to accommodate operational situations such as variation in the produced gas composition, variation in the three-phase (gas, oil and wa-ter) separation pressure and the equipment natural perfor-mance degradation.

To solve this issue, it was necessary to review together with the electric motor manufacturer cooling system to iden-tify any design margins that could be used to increase the motor rated power. However, as there is no guarantee that this type of solution can be adopted in all cases, it is recom-mended to select the driver with a 10% power margin to the highest demanded power point in the compressor curve, instead of the specified points.

This selection criterion may impact the power generation system design. In such situations it may be needed to re-duce the driver power margin to avoid oversizing the power generation. Even in such cases, the electric driver selection margin must reference the highest demanded power point in the compressor curve, with a minimum margin of 4%.

Gas composition uncertaintiesThe type of gas to be handled heavily impacts the selec-

tion of the compressors. For upstream units, the gas com-

position adopted as design parameter for the compressor is achieved by simulation and fluids analysis results obtained in the exploration phase of the reservoir.

Frequently, the samples are taken from few exploratory wells, while the operating unit compresses a blend of gas from several wells. This process brings a great level of un-certainty to the estimated compressed gas composition.

In one platform, the molecular weight difference between the gas composition used as design parameter and the composition achieved in operation exceeded 10%. While the specified gas predicted a molecular weight of 21.7 kg/kmol at the compressor suction, the actual gas was as light as 19.0 kg/kmol. This difference resulted in up to 40% reduced flow capacity (Figure 2).

n Figure 2: This schematic shows how the change of the com-pressed gas molecular weight affects the compressor capacity.

The main reasons for this divergence were the three-phase separation temperature reduction and the production of the reservoir’s gas cap during the first year of the unit. The well’s connection campaign to the platform lasted for about two years and during this period the capacity of the compressors was severely reduced. (The final gas blend had a molecular weight similar to that used in the design.)

It is noteworthy that the gas composition of the reservoir’s gas layer is not known in advance, unlike the composition of its oil and associated gas, which can be estimated from samples taken in the exploration phase.

Some of the uncertainties in the design parameters for a project may not be reduced in a feasible way. A possible alternative to accommodate large variations in operating conditions, therefore reducing the risks associated with the gas composition uncertainties, is to specify some other op-erational conditions in the design phase. This could be from information taken from other exploratory wells or similar reservoirs, or even by extrapolating the predicted composi-tion to more extreme scenarios.

Importantly, this alternative would result in a slight in-crease in investment cost, from extra engineering hours and maybe even the design or manufacture of a second

continued on page 88

CT258.indd 4 9/23/13 11:07 AM

Continental Controls Provides Air-Fuel Ratio Control for Gas Engines: •State-of-the-ArtControlforallGaseousFuels

•DesignedforRichorLeanBurnOperation

•MaintainEmissionsComplianceevenwithDifficultOperatingConditions

•ImprovedMixingofAirandFuel

•MeetTomorrow’sEmissionsStandardsToday

8845RehcoRoad,SanDiego,CA92121Tel858/453-9880Fax858/453-5078www.continentalcontrols.com

AllFuelValvesHaveBeenDesignedSpecificallyforUltra-lowEmissionsControlonGasEngines.

CallToday!Our sales and engineering staff will be happy to help you select the perfect fuel valve for your application.

888/453-9880www.continentalcontrols.com

VM350Mixing Venturi

for Mixing Air & Fuel

VMI600Venturi Mixing

Inserts for Existing

Carburetors

GV1 Electronic

Gas Fuel Valve

CatalystMonitorandDataLogger

Health Monitoring of NSCR or Oxidation Catalysts

ECV5 Emissions

Control Valve

EGC2Electronic Gas Carburetor for Engines from 10 hp to about 250 hp

EGC4Electronic Gas Carburetor for Engines from

250 hp to 500 hp

CCC.indd 1 9/19/12 4:44 PM

OCTOBER 2013 88 COmpREssORtech2

gear set with different output speed, but would certainly re-duce production losses — a far greater cost — due to these uncertainties during operation.

For most projects, a different output speed should be suf-ficient to accommodate the different gas composition sce-narios. For a wider gas composition range, a second set of compressor internals or speed variation should be evaluated.

Compressor internal corrosionAs described above, in the first projects to adopt fixed-

speed electric motors as compressor drivers, it was opted to have identical electric motors driving both low- and high-pressure compressors.

Consequently, the low-pressure compressor was arranged in a single-section, straight-through casing and the high-pressure compressor was arranged in two sections in back-to-back casing. This configuration results in a significantly higher suction pressure for the third section (Figure 3).

n Figure 3: These typical compressor trains arrangements show their influence on interstage pressures.

In units in which the compressed gas contains non-neg-ligible fraction of CO2 (typically above 0.1%), the conditions at the suction of the final stages of compression, saturated gas at high pressure, can have a severe corrosion potential (API, 1999) for carbon steel components, such as pipes, vessels and the compressor itself.

This phenomenon was quite evident in one of the first three platforms to use fixed-speed electric motors, where the com-pressors suffered severe internal corrosion in the casing and in the first diaphragm of third section (both carbon steel), while the pipes and the scrubber (manufactured in stainless steel) in the suction of the compressor were unaffected.

In a later project, where a higher fraction of CO2 was pre-dicted, the material selection by the compressor manufac-turer foresaw the corrosive potential on carbon steel com-ponents, opting to use stainless-steel cladding in the casing internal surface and to manufacture the diaphragm entirely in stainless steel.

For the unit suffering from CO2 corrosion, a similar solution was adopted: coating the casing internal area and the first dia-phragms with electrolysis nickel platting. This case, and the dif-ficulty in applying this coating in compressors already operat-

ing in offshore units, leads to a revision in the internal technical requirements for offshore gas compressors, resulting in corro-sion-resistant materials being adopted from the design phase.

RecommendationsIt is the authors’ opinion that the adoption of fixed-speed

electric motors as main compressor drivers brought a great simplification and robustness to the compression systems in the Rio de Janeiro Operational Unit platforms.

It is a good option for future projects, especially for those without a large variation or uncertainty in the gas to be compressed. The problems described in this article can be avoided with some adjustments in the technical specifica-tions for gas compressors.

To avoid electric motor overload events, two strategies are recommended. The first is the extension of the 10% power margin requirement for the electric motor selection from the compressor rated point to the maximum compres-sion power point in the compressor operational envelope. In some cases, this criterion may need to be adjusted to avoid power generation oversizing.

The second is the implementation of an electric power (or current) limiter control loop in the compressor capacity control-ler, acting on the suction throttle valve. For such a limiter loop to work, the throttle valve must be installed inside the com-pressor recycle loop, eliminating the need of the sometimes used starting valve.

To minimize the risks associated with reservoir uncertain-ties concerning compressed gas composition, it is recom-mended that the design includes alternative scenarios, with both lighter and heavier gas compositions. As a way to add flexibility to the compression plant, the project can include a second gear set design with a different output speed to accommodate some of these scenarios.

Finally, although the compressor internal corrosion issues are not caused by its fixed-speed driver, this exacerbated fra-gility in recent projects with significant CO2 content by increas-ing the last section suction pressure. With a careful analysis of both materials and coatings to be used in the compressor’s internal components, especially on the higher pressure ones, these corrosion-related failures can be avoided.

The use of fixed-speed electric motors as gas compres-sor drivers is a simple solution and, with the above adap-tations in our technical specifications, should prove to be even more robust and reliable. CT2

ReferencesAPI 617, 2002, “Axial and Centrifugal Compressors and

Expander-compressors for Petroleum, Chemical and Gas Industry Services,” Seventh edition.

API Spec 6A, 1999, “Specification for Wellhead and Christmas Tree Equipment,” 17th edition.

Miranda, M.A. and Meira, O.G. 2008. “Life cycle assess-ment of turbomahcinery for offshore applications — updat-ed with field data,” Proceedings of the 37th Turbomachinery Symposium, pp. 103-110.

CT258.indd 5 9/23/13 11:08 AM

Samsung.indd 1 8/21/13 8:57 AM

Advertisers’ Index

ACI Services, Inc. ...........................................93 www.aciservicesinc.com

Altronic, LLC .......................................25, 52-53 www.altronic-llc.com

*ARIEL ................................................................1 www.arielcorp.com

ARMCO Compressor Products Corp. ..........94 www.armcocompressor.com

AXH air-coolers ..............................................19 www.axh.com

BETA Machinery Analysis .............................29 www.BetaMachinery.com

BG Service Co. Inc, The ................................85 www.bgservice.com

*Burckhardt Compression AG ..........................5 www.burckhardtcompression.com

Cameron ....................................................48-49 www.c-a-m.com

Catalytic Combustion Corporation ..............33 www.catalyticcombustion.com

Compressor Elements ...................................57 www.compressorelements.com

*Compressor Products International .............13 www.c-p-i.com

Continental Controls Corporation ................87 www.continentalcontrols.com

Continuous Control Solutions ......................27 www.ccsia.com

Cook Compression ........................................31 www.cookcompression.com

DCL International Inc. ......................................7 www.dcl-inc.com

*Dresser-Rand ............................................37, 55 www.dresser-rand.com

ECOM America ...............................................47 www.ecomusa.com

E Instruments International ..........................77 www.E-Inst.com

*Elliott Group ...............................Second Cover www.elliott-turbo.com

Ellwood Crankshaft Group ............................67 www.ellwoodcrankshaftgroup.com

FLP, Fluid Line Products ...............................59 www.fluidline.com

*GE Oil & Gas ...................................Third Cover www.geoilandgas.com

GUARDIAN Engine + Compressor Control ....43 www.guardiancontrol.com

Hahn Manufacturing Company .....................77 www.Hahnmfg.com

Harsco Industrial Air-X-Changers ................45 www.harscoaxc.com

*Heinzmann GmbH & Co. KG ....................70-71 www.heinzmann.com

Josef Mehrer GmbH & Co. KG ......................41 www.mehrer.de

*KB Delta Compressor Valve Parts Mfg. ........................................................17 www.kbdelta.com

Kiene Diesel Accessories, Inc. .....................67 www.kienediesel.com

*LMF Leobersdorfer Maschinenfabrik AG .....39 www.LMF.at

MIRATECH ......................................................11 www.miratechcorp.com

MOTORTECH GmbH ......................................15 www.motortechamericas.com

Murphy by Enovation Controls ........... 35, 83 &Fourth Cover

www.fwmurphy.com

Nidec ASI S.p.A ..............................................61 www.nidec-asi.com

Neuman & Esser Group .................................21 www.neuman-esser.com

PROGNOST Systems GmbH .........................65 www.prognost.com

Reagan Power & Compression .....................81 www.reaganpower.com

Reynolds French ............................................69 www.r-f.com

*Rolls-Royce ......................................................9 www.rolls-royce.com

*Samsung Techwin Co., Ltd. ..........................89 www.samsungcomp.com

Shannon/INSULTECH ....................................73 www.blanket-insulation.com

SKF ..................................................................75 www.skf.com

SKF Magnetic Mechatronics S.A.S ...............63 www.skf.com/s2m

Summit Industrial Products ..........................78 www.klsummit.com

SYNTHOSOL ...................................................23 www.mastersprocess.com

*Tech Transfer, Inc. ........................................2-3 www.techtran-hou.com

*Testo, Inc. .......................................................79 www.testo350.com

T.F. Hudgins, Incorporated ...........................91 www.tfhudgins.com

*Voith Turbo Inc. ..............................................10 www.usa.voithturbo.com

*Further information on this company’s products can be found in the 2013 Edition of the Global Sourcing Guide (at GSGnet.net) and 2013 Compression Technology Sourcing Supplement (at CTSSnet.net).

Web: www.compressortech2.com • Phone: 262-754-4121 • Fax: 262-754-4175E-mail: slizdas@dieselpub.com • Address: 20855 Watertown Road, Suite 220, Waukesha, WI 53186

74 Natural Gas Production77 Gas Gathering Company70 Natural Gas Process Plant Operations72 Gas Transmission Pipeline

Compressor Operations75 Natural Gas Storage Company73 Chemical or Petrochemical Process

Company76 Refinery Operations91 Consulting Engineers or Contractor95 Research and Development,

Technical Support Organizations, Technical Universities and Libraries

97 Students54 Distributing, Servicing and

Overhauling Engines & Compressors

1. Do you wish to receive COmPRESSORtech2 magazine FREE of any charges?

YES Digital or Print

NO

3. MY JOB FUNCTION IS:

EN Engineering

PR Production/ Purchasing

OP Operating/ maintenance

AD Administrative/ marketing

OT Other (describe)

COMPLETE THE 4 BOXES FOR YOUR FREE SUBSCRIPTION.

2. MY COMPANY’S PRIMARY BUSINESS IS... (Please Check One)

2013

63 manufacturing Compressors65 manufacturing or Packaging

Compression Sets and Systems40 manufacturing Natural Gas or

Dual-Fuel Engines41 manufacturing Gas and Steam Turbine

Engines and Gas Expanders62 manufacturing Industrial Power

Transmission Products & Compressor Components, Accessories & Control Systems

99 None of the above. my company’s business is

COMPRESSORDedicated To Gas Compression Products & Applications

4. NAME ______________________________________________________________________ TITLE ______________________

COMPANY _________________________________________________________________________________________________

ADDRESS __________________________________________________________________________________________________

CITY & STATE/OR/COUNTRY ___________________________________________ POSTAL/ZIP CODE ______________________

SIGNATURE (REQUIRED) ______________________________________________ DATE (REQUIRED) ______________________

E-MAIL (REQUIRED) _________________________________________________________________________________________

IMPORTANT

You must check BOTH a Business and Job

Function box for your subscription to be

processed. PLEASE SIGN & DATE CARD

n NEw

n RENEw

CT_Oct13_AdIndx.indd 1 9/24/13 4:20 PM

Oil Purification EquipmentOil Filtration

Systems has introduced a new series of oil purification equipment to remove var-nish from hy-draulic and lu-brication oils.

By using two varnish mitigation tech-nologies, a single varnish removal sys-tem (VRS) can remove either soluble varnish or suspended varnish from oil, the company said.

The VRS is suitable for purifying turbine lube oil (such as Frame 7FA and 7EA gas turbines), hydraulic oil, Fyrquel EHC fluid, paper machine oil, compressor oil and oil for many other types of rotating equipment.

VRS equipment employs granular adsorbent media to remove soluble varnish found in warm oil at normal operating temperatures of 100°F (38°C) and higher. At cooler tempera-tures (typically under 70°F [21°C]), varnish is suspended and can be re-moved by depth media filter elements. The VRS housing, which comes in multiple sizes, accepts either media.

www.oilfiltrationsystems.com

Bearing HeatersLudeca Inc. has added two new

models — the Eddytherm Portable and the Eddytherm 2x — to its line of induction heaters.

Both heaters allow the user to

set the proper time and temperature to prevent premature bearing failures due to improper heating or overheating dur-ing installation. A magnetic temperature probe continuously measures and dis-plays actual temperature, while a stand-by feature permits holding the tempera-

ture at a preset level for an indefinite time. The heaters automatically de-magnetize bearings after heating, while visual and audible signals indicate the end of the heating/demagnetizing cycle.

The Eddytherm 2x features a swivel arm and is suitable for bearings up to 176 lb. (80 kg) while the Eddytherm

Portable is suitable for bearings up to 22 lb. (10 kg). The heaters are de-signed for shrink-fitting bearings, as well as heat sleeves, impellers, rings, couplings, crane wheels and gears, the company said.

www.ludeca.com/prod_eddytherm.php

TFH Gas Flowmeters are the easy way to meet air quality regulations.

Get features, flexibility and simplicity for a wide range of oil and gas applications, including flares, storage tanks, VRUs, compressor vents, starting gas and more.

� Configurable in a variety of styles

� Low pressure drop

� Broad flow range (10 to 60,000 fpm velocity)

� Low total installed cost

� Mass measurement output directly from meter over multiple communication options

� Data logging of 31 separate, 24-hour daily totals with time and date stamp

� In-situ calibration verification with Cal-V™ and Zero Cal-Check™

Contact us today for compliance solutions.

�

©2013 T.F. Hudgins, Incorporated

Your Machinery Solutions Specialist SM

www.tfhudgins.com713-682-3651sales@tfhudgins.com

*Model FT3 from Fox Thermal Instruments, Inc.;private labeled by T.F. Hudgins, Incorporated.

Winner ofFlow Control’s

Innovation Award for 2013 and Processing’s

Breakthrough Product of the Year Award

for 2012*

TFH 1000Portable

TFH 3000Inline

GAS FLOWMETERS

Accurate. Simple. Reliable. Versatile.

TF-Hudgens.indd 1 9/18/13 1:42 PM

PRODUCTSFEATURED

OCTOBER 2013 91 COmpREssORtech2

CT_Products_Oct.indd 1 9/23/13 3:44 PM

Dictionary_OnSale.indd 3 9/20/13 11:20 AM

3

2

457

6

T E C E W R A T I N G S U B S C R I P TN O I T A C I F I D O M U P O W E R N GE L R E E R C E D I X O N O M K O E N JM W T N G N O I T I N G I Y D G E I I QT N E G Y X O Z R L H M N D R R T M A SA X M M N X Z E P Z R O B E G S A G T NE X L C I W T N I A R N S R E I T Z P JR J M D O L J E A C R S E T T V L P A CT D E F I N S Z A T I T M P A U F U C HR O K F E G V N N O U E I C D N R E T TE N I T R O G E N O B R A C O R D Y H RT K M V W G I B R R C T A I U U T A A AF M O L E C U L E S I L T L A L E J R EA T L M I B C G R O I U E L G F A B N DS R E F S T U E N F L O F A X A R T A IZ D F N B L P F O O F U N W N M S S E FS E K L A U A R S L E C O S Y S T E M LJ B K T S L N T G L O B A L M C F V P UE R E Q U I P M E N T W J C R U F L U SP E X H A U S T I R Y V T T N Q K Q G H

Taking Aim At EmissionsAcronymAftertreatmentBenzeneCaliforniaCaptainCarbonClean ConversionDecreeDioxideDual FuelEarthEcosystemEfficientEquipmentExhaustFilterGlobalGreenHazardousHydrocarbonIgnitionMetricModificationMolecules

MonoxideNatural GasNitrogenOxygenParticulatePlanetPowerProgressionRatingsRegulateSlaterSlimeSmog MonsterSmokeSolutionStandardSubscriptSulfideSulfurSuperscriptTearsTestingTiersTreatmentVacation

Visit www.compressortech2.com for answers

Scheduled Downtime DJ SlATER, PuzzlEMASTER

CT2_Oct_Puzzle.indd 1 9/23/13 10:06 AM

ACI Services, Inc. • Cambridge, Ohio • www.ACIServicesInc.com • (740) 435-0240

Radial Valves

Radial Deactivator

Rotavator™

Single Deck Valves

Higher efficiency means dollars saved. The ACI team of Compression Experts developed new, radial poppet valve and capacity control technology to manage capacity, reduce fuel consumption, lower emissions and increase overall revenue. Call the ACI Compression Experts today for more information on the next generation valve technology.

ACI.indd 1 6/14/13 11:34 AM

MarketplaceMarketplace

ARLA Engineering Service

to Simulate Vibrations in Drive Systems• torsional and lateral vibration analysis• rotordynamics & bearing analysis (fluid-film)• considering complete drivelines with motors, engines, compressors, gears, couplings• steady-state and time-transient simulation• simulation software (ARMD 5.8)

Int’l Seminar ROTOR DYNAMICS & BEARINGS Cologne, Germany: October 28-31, 2013

ARLA Maschinentechnik GmbH,GERMANYInternet: www.arla-online.com

Arla_2013.indd 1 7/12/13 10:21 AM

Outside Regional Sales Manager, Texas- Excellent opportunity selling portable emissions

analysis equipment to the stationary engine/gas compression market.

- Must understand end-user applications, recognize the requirements and be able to present a solution using our products.

- Experience in working with reps & technical distributors.

- Ability to quickly learn new technologies and confidently present them.

Please submit resumes to:ecom.jobs@ecomusa.com

Condition MonitoringSoftware - Consulting Services - Training - Rerates Sleeve Seals - Aero Design - Wireless Instruments

Flexware, Inc.sales@flexwareinc.com

1-724-527-3911

Flexware_Classified.indd 1 9/9/13 10:33 AM

EXPLOSION PROOFAC&DC ENGINE STARTING SYSTEMS• STARTER MOTORS • ALTERNATORS

• SWITCHES • CLASS I, DIV. 1&2, GROUP D

UNITED STATES ENERGY CORPORATION1600 MISSILE WAY, ANAHEIM, CA 92801

(714) 871-8185 • (714) 871-9229 FAXWWW.USENERGYCORPORATION.COM

U.S. Energy Corp 1k x 1" 3/11/03 11:06 AM Page 1

From

Perfect For Brochures, Web Attachments

Custom

Compressortech2

Reprints

Phone: 262-754-4100E-mail: mgraesing@dieselpub.com

Contact Mary Graesing for pricing and details

( just in case they missed it)& Bragging Rights

CT_ReprintAd_BWQuarterPg.indd 1 11/20/12 1:07 PM

Contactsyildiz@dieselpub.com

for Marketplace Rates

CT_Oct_Mrktplc.indd 1 9/24/13 12:11 PM

Armco_AugSept.indd 1 9/24/13 4:53 PM

OCTOBER 2013 95 COmpREssORtech2

A 1968 edition of Diesel and Gas Turbine Progress re-ported that the first two Centaur installations were in gas pipeline applications at El Paso Natural Gas and Columbia Gulf Transmission stations. Both Centaurs drove Solar C30 centrifugal compressors, specifically designed for use with the Centaur.

Solar had to move rapidly to stay ahead of a competi-tor, Cooper Bessemer, which was busy developing a 3000 hp (2237 kW) gas turbine. By 1969, Solar had uprated the Centaur to 3300 hp (2461 kW), reporting that more than 100 of the higher-rated units had been ordered. Most of the early 3300 hp (2461 kW) units went to customers in the U.S., however, international business was blossoming and the biggest Centaur purchaser, Gas del Estado in Argen-tina, had ordered 16 units by that time.

The May 1976 issue of Diesel and Gas Turbine Progress reported that the Centaur rating had evolved to 3830 hp (2856 kW) and it was widely being used for gas compres-sion and power generation at offshore platforms as well as in land-based applications. Continuous development has increased the Centaur 40 gas turbine to a 4700 hp (3520 kW) ISO rating today.

In 1985, Solar introduced a more powerful member of the Centaur engine family — the Centaur 50, now rated at 6130 hp (4570 kW). By 1992, when it introduced SoLo-NOX gas turbines, Solar had been developing combus-tion technology for nearly 20 years to reduce exhaust emissions. This dry-emissions system, which reduces the formation of NOX, CO and unburned hydrocarbons is available for the Centaur and all large gas turbines in the Solar lineup.

The Centaur is a two-shaft gas turbine, with the compres-sor turbine shaft having an 11-stage axial compressor with variable inlet guide valves, that in its current form develops a 10.3:1 pressure ratio for the Centaur 40 and 10.5:1 for the Centaur 50.

Only a quarter of the air produced by the compressor is used for combustion of natural gas in the annular combus-tor. The excess air is mixed with combustion products to

reduce the gas temperature at the turbine inlet and also is used as cooling air to keep metal temperatures in the combustor and turbine assembly relatively low to increase service life.

The combustor has either 10 or 12 fuel injectors, depend-ing on the model. The gas-producer turbine is a two-stage reaction turbine. The mechanical drive power turbine has a single stage. The rotors run in tilting-pad journal bearings and the thrust bearing is a fixed, tapered land bearing.

The gas turbine is composed of standard air inlet, com-pressor, compressor diffuser/combustor, turbine, exhaust collector and accessory drive sections or assemblies. So-lar’s factory-built packages incorporating the Centaur gas turbine are completely integrated and fully operational, equipped with the necessary accessories and auxiliary sys-tems. The drive packages are combined with one or more Solar centrifugal compressors or are used to drive other gas compressors, pumps and electrical generators, the lat-ter in a single-shaft configuration.

Solar also developed a line of centrifugal gas compressors to match the Centaur’s speed and power ratings. Centaur compressor sets combine the gas turbine driver package with matching integrated centrifugal compressor modules, in either single-body, two-body or three-body tandem configu-rations, for direct-drive or gear-driven applications.

Compressor sets with a single Solar compressor can produce pressure ratios of over 3:1, while multiple, tandem-mounted compressors can produce ratios approaching 30:1. The Solar model C40 compressor is available with one or two stages for gas pipeline applications at pressure ratings to 1600 psig (110 bar). Four other models are avail-able in multistage configurations for pressure ratings as high as 3000 psig (207 bar).

With about 3000 units in service by early 2013, the Cen-taur gas turbines rank second only to the Saturn in total units installed worldwide. Now a subsidiary of Caterpillar Inc., Solar continues to produce the popular Centaur units for compressor drive, power generation and other mechani-cal drive applications. CT2

Solar Centaur Gas TurbineCurrent ISO Compressor Set Rating At 59°F (15°C) And Sea Level

Centaur 40 Centaur 50

Power 4700 bhp 3500 kW 6130 bhp 4570 kW

Heat Rate 9125 Btu/hph 12,905 kJ/kWh 8500 Btu/hph 12,030 kJ/kWh

Exhaust Flow 150,320 lb/hr 68,185 kg/hr 149,380 lb/hr 67,760 kg/hr

Exhaust Temperature 835°F 450°C 960°F 515°C

Compressor Turbine Maximum Speed

15,000 rpm 15,000 rpm

Power Turbine Maximum Speed

15,500 rpm 16,500 rpm

Driver Package L x W x H

19.7 x 8.1 x 8.9 ft. 6.0 x 2.5 x 2.7 m 19.7 x 8.1 x 8.9 ft. 6.0 x 2.5 x 2.7 m

Driver Package Weight 33,000 lb 14,970 kg 36,000 lb 16,330 kg

Cornerstones Of Compression story continued from page 96

CT264.indd 2 9/24/13 12:14 PM

C ornerstones Of Compression

OCTOBER 2013 96 COmpREssORtech2

Solar Turbines has produced more than 13,800 gas turbine systems that have collectively logged more than 1.3 billion operating hours.

Although the company’s roots date to 1927, it was not un-til 1960 that Solar introduced its first industrial gas turbine. That model, the Saturn, became the world’s most widely used industrial gas turbine with some 4800 units applied in 80 countries. With development over time, the Saturn’s rat-ing increased from 1006 hp (750 kW) to a current ISO rating of 1589 hp (1185 kW).

Building on the early success of the Saturn, Solar began work on a larger gas turbine in the mid-1960s. Although modeled closely on the Saturn, basic changes in the new model revolved around two premises: a design objective of operating 30,000 hours in continuous duty service before any maintenance would be required on major components such as combustion section, compressor and turbine; and incorporating new features to achieve lower specific fuel consumption at a nominal 3000 hp (2237 kW) rating.

Labeled the Centaur, the larger model entered service in 1968 with a rating of 2700 hp (2015 kW), but it was soon uprated to achieve the 3000 hp design goal. The straight-through flow design produced a simple cycle thermal ef-ficiency of 25%. An 11-stage axial compressor on that first model produced a pressure ratio of 8:1, significantly higher than the Saturn’s 6:1.

The Centaur compressor section included variable inlet guide vanes and variable stator vanes in the first two stages to eliminate the possibility of compressor surge on starting and light load operation. These features were used in com-bination with a compressor discharge bleed valve, rather than the interstage bleed used with the Saturn.

Solar claimed that the compact, space efficient Centaur package was about one-twentieth the weight and one-fourth of the volume of a comparable heavy-duty, slow-speed re-ciprocating engine. It was a sixth of the weight and half the volume of a medium-speed reciprocating engine.

Solar’s Centaur Gas Turbine > Powerful units are widely used in

pipeline applicationsBy NOrm ShAde

continued on page 95

n The Centaur 50, at 6130 hp (4570 kW), is the highest-rated model of the Solar Centaur gas turbine series.

CT264.indd 1 9/23/13 12:12 Pm

GE-oil.indd 1 9/19/13 9:02 AM

Murphy’s Engine Integrated Control System (EICS) combines key components into one package pre-calibrated and dyno-tested specifically for your engine model. The EICS is preconfigured for your convenience, ensuring your engine will run at optimum performance without the need for manual field adjustments.

Give your outdated engine optimal EFFICIENCY, renewed LIFE, reduced EMISSIONS...with one solution!

Introducing the turn-key package from Murphy, Engine Integrated Control System (EICS) – one package gives you all major components:ignition, air/fuel control, and speed governing.

131

1297

8

-201

3

For more details please visit: www.fwmurphy.com/ad/eics_puzzle_ct2 or call: 918.317.2613

Visit us at Booth #718

Murphy_EICS.indd 1 9/17/13 10:05 AM