Condition Monitoring Solutions for Reciprocating Compressors

GEEnergy

Condition Monitoring Solutionsfor Reciprocating Compressors

Why Monitor?As one of the oldest compressor designs, recips enjoy unique

capabilities and are quite flexible with features such as broad capacity

control ranges and the ability to compress gas regardless of mole

weight or k value. Add mutiple stages and they can compress a gas

to extremely high compression ratios. Consequently, they’re an ideal

fit for selected applications—such as hydrogen compression in the

de-sulfurization process of many refineries—and as part of the

low-density polyethylene production process in chemical plants,

to name just a few.

However, reciprocating compressors suffer from one very serious

drawback: high maintenance costs. In fact, compared to similarly

sized centrifugals, recips can consume as much as five times the

amount of maintenance dollars.

That’s why a continuousmonitoring system is so important. Specifically

designed to meet the unique machinery protection and condition

monitoring needs of recips, our solutions can help close the gap,

bringing your recip maintenance costs closer to the levels associated

with centrifugals while simultaneously improving reliability, availability,

and safety. And, with patented* technology, comprehensive services,

and over 25 years experience monitoring reciprocating compressors,

no one is better equipped to help you.

* United States Patents 4,987,774; 6,421,571; 6,826,490; 6,937,941; 6,934,696

Great Britain Patent 2,408,3381

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Centrifugals Recips

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YEARS

1

2

3

4

5

6

7

8

1 2 3 4

HYDROGEN RECYCLE COMPRESSORCumulative Unplanned Repair Costs

Without monitoring With monitoring

Recips can consume five times as manymaintenance dollars as an equivalentlysized centrifugal compressor!

A monitoring system from GE will often morethan pay for itself in the first year, and can savemillions of dollars over the life of the compressor.

2

Frame VibrationIncreases in frame vibration can indicate problems

such as imbalance due to unusual pressure

differential or inertial unbalance, looseness in

the foundation attachment (such as deteriorating

grout or shims), and high moments caused

by excessive rod load.

PRIMEMOVER

MULTI-EVENT WHEEL

Continuous Rod LoadCombined (inertia and gas) rod loads

calculated at the crosshead provides

information about the lubrication condition

of the crosshead pin. Insufficient reversal or

excessive rod load can be identified and

corrected before costly running gear

damage occurs.

Discharge Gas TemperatureContinuous monitoring of discharge gas

temperature can give an indication of worn

valves, unloaders, excessive compression ratio,

or insufficient cooling water.

3500 Monitor: 3500/61 6-Channel or3500/65 16-Channel Temperature MonitorTransducer: RTD or Thermocouple

Piston Rod/Plunger PositionX-Y proximity probes observing the piston rod

provide information on rod bow and rider band wear.

Continuous monitoring gives maximum magnitude

and direction of rod movement along with the crank

angle at which the maximum occurs. The source of

movement can be identified, enabling the proactive scheduling

of maintenance for rider band replacement or crosshead repair.

Monitoring plunger position in hyper compressors provides

protection against detoriating plungers.

Suction/DischargeValve TemperatureSuction and discharge valves are typically the

highest maintenance items on recips. Faulty

valves can significantly reduce the compressor’s

efficiency as well as increase combined rod load.

By recompressing the same gas, a leaky valve

becomes hotter than normal, causing the valve cover plate

temperature to increase. By monitoring both absolute valve

temperature, and differential temperature between a group of

valves, valve problems can be spotted early and repaired before

efficiency losses mount.

Crosshead AccelerationCrosshead-mounted accelerometers can detect

machinery problems due to impact-type events

such as crosshead looseness, liquid ingestion

into the cylinder, or excessive clearance in the

wrist pin bushing.

3500 Monitor: 3500/70MTransducer: 330400 or330425 Accelerometer

Main Bearing TemperatureThis measurement indicates problems related to fluid-

film bearings, including overload, bearing fatigue,

or insufficient lubrication.

3500 Monitor: 3500/72M 4-ChannelRod Position MonitorTransducer: 3300XL SeriesProximity Transducer

3500 Monitor: 3500/70M 4-ChannelImpulse/ Velocity monitorTransducer: 330500 Velomitor®or 190501 Velomitor CTPiezo-Velocity Transducer

3500 Monitor: 3500/77M 4-ChannelCylinder Pressure MonitorTransducer: 165855 CylinderPressure Transducer



Recip Monitoring In Detail.

3

Suction Gas TemperatureContinuous monitoring of suction gas temperature

provides a useful baseline against which to compare

suction valve temperature. Relative changes in the

temperature between suction valves and suction gas

can give an indication of the worn suction valves.

In addition, suction gas temperature, combined with

the integrated equation of state engine in System 1®

software, provides the information necessary to

calculate capacity at suction conditions and cylinder

flow balance numbers.

3500 Monitor: 3500/61 6-Channelor 3500/65 16-ChannelTemperature MonitorTransducer: RTD or Thermocouple

Pressure Packing Case TemperatureContinuous monitoring of pressure packing

temperature provides useful information on

developing problems related to the packing,

including excessive wear, insufficient cooling,

and inadequate lubrication.


Crosshead Shoe TemperatureContinuous monitoring of crosshead shoe (slipper)

temperature provides useful information on developing

slipper problems such as overload, fatigue, and

insufficient lubrication.


Multi-Event Keyphasor® SignalA proximity probe observing a multi-toothed wheel on

the crankshaft provides a precise reference timing signal

every 30 degrees of rotation in addition to a once-per-

turn reference point. This allows measurements such

as rod position and cylinder pressure to be correlated

with a highly accurate crank angle measurement. Rod

position can be captured at the same point in the piston

rod stroke, and cylinder volume can be computed

precisely at each point in the stroke for highly accurate

P-V curves.

3500 Monitor: 3500/25Keyphasor ModuleTransducer: 3300XL SeriesProximity Transducer

Cylinder Pressure ProfileThe single most effective way of determining the

overall health of a reciprocating gas compressor is

by examining the cylinder pressure profile. Online

access to the internal pressure for each compressor

cylinder enables continuous monitoring of cylinder

pressures, compression ratios, peak rod loads, and

rod reversal. This provides valuable information on the

condition of suction valves, discharge valves, piston

rings, packing glands, and crosshead pin. And,

interfacing the 3500 System with System 1 ® software

provides valuable diagnostic plots such as Pressure

versus Volume (P-V), Log P versus Log V, and pressure

versus crank angle.

3500 Monitor: 3500/77M 4-ChannelCylinder Pressure MonitorTransducer: 165855 CylinderPressure Transducer

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Frame Vibration

Main Bearing Temperature

Crosshead Acceleration

Multi-Event-Per-Revolution Keyphasor® Signal

Cylinder Pressure

Combined Rod Load3

Piston Rod Position

Hyper Plunger Position

Suction Valve Temperature

Discharge Valve Temperature

Pressure Packing Case Temperature

Crosshead Shoe Temperature

Suction Gas Temperature

Discharge Gas Temperature

Online Gas Analyser Data Input

Trending & Analysis Software

Malfunction/Measurement In Detail.

1 All of the measurements marked in each column are highly recommended to detect the malfunction.

2 The red-marked �measurements are recommended for auto-shutdown machinery protection.

3 Combined rod load shares the sensors of cylinder pressure but is used for specific malfunction and protection functions.

4

Integrated MachineryProtection andMachinery ManagementOur powerful 3500/22M TDI Rack Interface

Module eliminates the need for bulky external

data acquisition hardware or special interface

modules between the monitor rack and

software. Simply plug an Ethernet cable

into the 3500/22M and you’re ready to

communicate with our powerful System 1®

software for advanced diagnostics, condition

monitoring, and other plant asset management

functionality. The result is a zero-footprint

solution requiring absolutely no additional

rack or cabinet space when augmenting

your basic machinery protection system

with System 1® connectivity.

And, the enhanced data collection technology

of our 3500/22M TDI allows earlier and

improved diagnosis of previously difficult-to-

ascertain transient events (such as cylinder

liquid ingestion).

• Fully compliant with the requirements of

American Petroleum Institute (API) Standard

670 for Machinery Protection Systems and

Standard 618 for Reciprocating Compressors.

• Available in 19” 14-slot EIA rack or space-

saving 12” 7-slot mini-rack.

• Available with a variety of high-quality display

options ranging from self-configuring VGA

touch screens to remote workstations to LCD

panels that mount directly on the rack face.

• Monitor modules available with 4-20 mA

recorder output signals for interfacing with

strip chart recorders and other analog based

control and automation equipment.

At the heart of our Recip Monitoring Solution is the Bently Nevada™3500 Series Machinery Protection System...

Single-cable Ethernetconnectivity to our System 1®software for advanceddiagnostics and conditionmonitoring functionality.

All monitor modules aretotally software configurablevia the 3500’s Rack InterfaceModule—key lockable toprevent unauthorizedtampering.

Keyphasor® module acceptsmulti-event-per-turn signals forgreater accuracy—requiredfor reciprocating compressorapplications where crank anglemust be precisely determined.

Highly reliable power suppliesaccept worldwide AC/DCvoltages/frequencies and canbe ordered as fully redundantto assure uninterruptedperformance.

New capabilities for assessingpiston rod vibration and positionat precisely defined crank anglesfor repeatable, useful informationon rider band wear, rod bow,and other conditions. Alsoapplicable to hypercompressorsusing plungers instead ofconventional pistons.

Powerful cylinder pressuremeasurements now availablefor the most complete pictureof reciprocating compressorhealth. Dynamic P-V curves,rod reversal measurements,and much more.

6- or 16-channel temperature monvariety of RTDs or thermocouples.differential alarming capabilities alloto be used for valve temperatures,process temperatures, bearing temcrosshead shoe (slipper) temperatupacking case temperatures, and aother machinery or process tempemeasurements.

A variety of relay modules are avaifor actuation upon user-configuraalarm and status events. Relays arereliable and intended for connectinmonitoring system to external annunand machinery control systems foauto-shutdown.

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nitors accept aAbsolute andw themonitorsgas or other

mperatures,ures, pressurevariety ofrature

Special-purpose 4-channel vibration modules aredesigned to address the casing vibration andcrosshead accelerationmeasurement requirementsunique to reciprocating compressors by providingreliable machinery protection without false ormissed alarms. Filtering, alarm delay, full-scalerange, transducer input type, and a host of otheroptions are fully software configurable on aper-channel basis.

Generic 4-channel vibration modulesaccept velocity, acceleration, andproximity transducers. Filtering, alarmdelay, full-scale range, transducerinput type, and a host of other optionsare fully software configurable on aper-channel basis. Used for a varietyof measurements on the recip’sprime mover.

ilableablehighlyng thenciatorsor

Fully digital communications of all monitoredparameters and statuses using a variety ofindustry-standard protocols—ideal forconnection to process and machine controlsystems rather than using analog (4-20mA) outputs. Supports time-stamping ofalarms and clock synchronization.

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The single most important measurement for condition monitoring of reciprocating compressors

is cylinder pressure. Armed with accurate cylinder pressure at each point in the piston’s stroke, a

Pressure-Volume (PV) curve can be constructed that provides indispensable information on your

machine’s health.

That’s why we’ve given particular attention to this vital measurement. With a robust sensor,

advanced signal processing functionality in our 3500/77M Recip Cylinder Pressure Monitor, and a

suite of graphical plots in System 1® software specifically for analyzing cylinder conditions, there’s

simply no better way to get inside your cylinders—where the action is.

Historically, measuring these conditions meant temporarily attaching transducers to indicator

valves on each cylinder. Although cumbersome, this practice was necessary because pressure

transducers simply couldn’t survive under long-term exposure to the harsh environment of cylinder

chambers. We knew that the key to reliable and effective assessment of machinery health—not

to mention convenience—was to design a sensor that could endure 24/7 exposure to such an

environment, eliminating the burden of constantly connecting and disconnecting every time you

wanted data. With our all-new Bently NevadaTM 165855 Cylinder Pressure Transducer, we’ve done

just that. It provides continuous static and dynamic pressure data and is specifically designed for

use with our 3500/77M Recip Cylinder Pressure Monitor. Innovative materials and construction

techniques† allow it to deliver reliable measurements in the extreme temperatures, pressure

cycling, and harsh chemical environments (such as H2S) inherent in reciprocating compressor

cylinder applications.

Available in a variety of pressure ranges from 100

psia to 10,000 psia, the 165855 has undergone

extensive testing. In fact, we’re so confident of its

performance that we offer something unique to

the industry: a 3-year warranty.

† U.S. Patent 6,955,090

Cylinder PressureWhere the Action Is.

TDC500

400

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CHG

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300

LOG

PRES

SURE

0 20 40 60 80 100

200

5 %/divDisplaced Volume Log Volume

Y Versus Crank AngleLeveraging the 3500 architecture, whichsimultaneously captures data across multiplechannels, this plot format enables users tocorrelate events across different measurementsand to correlate events with piston positioninside the cylinder. For example, the largeacceleration impulse event at top dead center(TDC) indicates liquid or debris ingestion.

POU

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Crank Angle

Performance Variablesat a GlanceRight click on a pressure curve to bring up this handysoftware variable reference box that displays theperformance variables for each chamber in thecylinder. Changes in these performance variables,such as cylinder flow balance, can confirmdiagnosis of valve, piston ring or pressure packingfailures. These values can be collected and trendedto identify long-term degradation.

Rod Position PlotsRod position plots display the total movement ofthe plunger or piston rod at the pressure packingcase. Effects of changes inmechanical clearances,such as plunger to guide bearing, crosshead tocrosshead guide, etc., and changes in averageposition, such as the thermal growth of a pistonrod at cold conditions (red curve) and operatingconditions (blue curve) can be seen in this format.

(not orbit or polar plot)

10

UP

0

-10

-20

Crank Angle :0

0 10 20 300

AMPLITUDE: 2 mil/div

360

Rod Load PlotsPlotting gas and combined rod load (shown inthe top left pane) with other measurements suchas crosshead acceleration and rod positionprovides the ability to detect problems such asmechanical looseness, excessive loading andinadequate reversal. For example, the impulseevent in the acceleration and rod positionwaveforms corrlates with the gas load reversalpoint and indicates a loose piston.

20 Degrees/divCrank Angle

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0

10

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0 100 200 300

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IMPULSE ACCEL OUTLINE

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200 300

Crank Angle Waterfall PlotsA waterfall plot allows the user to see how onecycle of compression compares with other cyclesover a long period of time. This enables the userto quickly changing parts of the cycle. The plot onthe left shows the closing point of the steplessunloader changing rapidly over a 2minute periodof operation. This indicates poor process controlor incomplete control loop tuning.100 200 300

10 degrees/div

19 Apr 18:50:12 33919 Apr 18:33:52 36019 Apr 18:32:58 36019 Apr 18:31:58 35919 Apr 18:23:30 35919 Apr 18:10:18 35919 Apr 18:09:28 36019 Apr 18:08:28 36019 Apr 17:52:26 35919 Apr 17:22:58 36019 Apr 17:22:03 35919 Apr 17:21:13 35919 Apr 17:20:13 36019 Apr 17:07:22 35919 Apr 17:06:30 36019 Apr 17:05:30 35919 Apr 16:57:59 36019 Apr 16:56:58 35919 Apr 16:56:05 36019 Apr 16:55:05 36019 Apr 16:53:14 35919 Apr 16:52:15 36019 Apr 16:51:16 35919 Apr 16:50:23 35919 Apr 15:48:20 36019 Apr 12:42:06 359 rpm

19 Apr 18:50:12 33919 Apr 18:33:52 36019 Apr 18:32:58 36019 Apr 18:31:58 35919 Apr 18:23:30 35919 Apr 18:10:18 35919 Apr 18:09:28 36019 Apr 18:08:28 36019 Apr 17:52:26 35919 Apr 17:22:58 36019 Apr 17:22:03 35919 Apr 17:21:13 35919 Apr 17:20:13 36019 Apr 17:07:22 35919 Apr 17:06:30 36019 Apr 17:05:30 35919 Apr 16:57:59 36019 Apr 16:56:58 35919 Apr 16:56:05 36019 Apr 16:55:05 36019 Apr 16:53:14 35919 Apr 16:52:15 36019 Apr 16:51:16 35919 Apr 16:50:23 35919 Apr 15:48:20 36019 Apr 12:42:06 359 rpm

500 100 200 300

10 degrees/div

500

PO

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80

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Pressure VersusDisplaced VolumePlotting indicated and ideal cylinder pressureversus displaced volume enables detection ofmalfunctioning seals (rings, valves and unloaders).Use of log-log scales permits earlier detection ofleaks. For cylinders with stepless unloaders apatented algorithm detects the valve closurepoint and adjusts the ideal curves.

Crank Angle OverlayLeveraging the 3500 architecture, which simultaneouslycaptures data acrossmultiple channels, this plot formatenables users to correlate events across differentmeasurements within a single plot pane. The plotformat incorporates graphics optimization algorithmsto enhance data presentation quality. This helps usermore quickly and accurately correlate events acrossmultiple meausurements.

Decision SupportSM

A Powerful DifferenceIn addition to System 1®’s powerful plotting, trending, andmanual data analysis capabilities,

you’ll find something unique: Decision Support functionality. Decision Support is System 1®’s

ability to automatically audit its collected data against user-embedded rules and knowledge,

detect mechanical or thermodynamic problems, and generate informative advisories that

we call Actionable Information®.

Actionable Information advisories are configured by you, to reflect your specific operating

practices and procedures. When a specific malfunction or condition is detected, System 1®

tells plant personnel what the problem is, how severe it is, and what to do about it—in real

time. Cell phone, pager, PDA, e-mail, desktop and process control system pop-up windows—

even conventional annunciator panels—they’re all supported as ways to communicate

Actionable Information advisories to the right people at the right time.

You can employ powerful built-in rules with our Recip RulePaks, ready-to-run collections

of intelligent rules just for recips, and/or you can build your own rules with our extraordinarily

easy-to-use RuleDesk features—just drag and drop logical and mathematical operators

into any sequence of conditions that correspond to a particular malfunction. The choice

is yours through a totally flexible system that lets you design rules specific to your process

and machinery, automate the data analysis function, and communicate required actions

and urgencies instantly to the right people—whether across the hall or across the globe.

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System 1®Optimization and Diagnostic SoftwareDon’t just protect your recips, proactively manage them with the enhanced condition monitoring

and Decision SupportSM capabilities of System 1®, our most advanced software ever.

System 1® is a platform for managing every asset in your plant . It brings together a variety of

condition monitoring technologies, maintenance management applications, reliability tools, process

control and historian data specifically for addressing the unique needs of reciprocating compressors.

The result is a total reciprocating compressor

solution, capable of providing:

• Discharge pressure

• Suction pressure

• Minimum/Maximum pressure for eachcrankshaft revolution

• Compression ratio

• Peak rod load for both compression and tension

• Number of degrees of rod reversal

• Suction volumetric efficiency

• Discharge volumetric efficiency

• Indicated horsepower

• Capacity at suction conditions

• Capacity at discharge conditions

• Suction power losses

• Discharge power losses

• Adiabatic clearance volume

• Flow balance of suction to discharge

• Adiabatic median capacity between suction and discharge capacity

• Adiabatic flow balance between theoretical discharge andsuction flow

• Power to median capacity ratio

• Displaced volume

• Adiabatic discharge temperature

RetrofitsWe make retrofits of our instrumentation systems simple by

managing the entire project. We handle everything, from drilling

and tapping holes in the machine to accommodate our transducers,

to packaging and configuring our monitoring systems into enclosures

suitable for your plant’s environment, to pulling field wiring, to

integrating our software into your plant’s IT infrastructure, to

documenting every detail.

TrainingWe train customers on not just the use and care of our products, but

also on the fundamentals of machinery—how to diagnose and prevent

compressor problems, how to balance and align compressors and

their prime movers, and how to proactively manage assets with the

right combination of technology, people, and processes.

Machinery DiagnosticsOur field engineers provide unbiased, third-party start-up and

commissioning assistance by collecting data from your machinery

and confirming that it is running within established mechanical

acceptance limits. We can also diagnose mechanical and

thermodynamic problems with your reciprocating compressors,

encompassing cylinders, frame, bearings, valves, foundation,

piping, and many other components.

Comprehensive ConditionMoniServices.

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Risk AssessmentWe can audit selected assets, or your entire plant , and provide

benchmarking data on which assets present the highest business

interruption and other risks, which technologies and methodologies

to use to mitigate risk, and the expected ROI of investments in

our solutions.

Balancing & AlignmentWe balance and align virtually every type of rotating machinery

found in industrial plants, with special capabilities to address the

needs of reciprocating machines, such as cylinder alignment and

foundation/footing problems.

Program ManagementFor customers that prefer to outsource all or part of their asset

management activities, we can assist. Whether your needs are

focused on a specific category of assets (such as reciprocating

compressors), a specific condition monitoring technology (such as

lubricant analysis), or a broader scope encompassing maintenance

management, reliability, condition monitoring, and other asset

management functions, we have the people, and experience, to

deliver the results you’re seeking.

toring

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©2007, General Electric Company. All rights reserved.Bently Nevada, Actionable Information, Decision Support, System 1, Keyphasor and Velomitor are trademarks,registered trademarks, or service marks of General Electric Company in the United States and other countries.

GEA-14927 rev. NC (08/07)

1631 Bently Parkway SouthMinden, Nevada USA 89423+1 775-782-3611www.ge-energy.com/bently

Condition Monitoring Solutions for Reciprocating Compressors

Technology

Transcript of Condition Monitoring Solutions for Reciprocating Compressors