Combustion and Emissions Properties of Heavy Oils · Power Generation/Marine Application Power...

PRINCETONMechanical and Aerospace Engineering

Combustion and Emissions Properties of Heavy Oils

Frederick L. Dryer

(Emeritus)

Department of Mechanical and Aerospace Engineering

Princeton University

Princeton, NJ [email protected]

KAUST FUTURE FUELS WORKSHOP

King Abdullah University of Science and Technology (KAUST)

Thuwal, Saudi Arabia

March 7-9, 2016This presentation includes information from

several manufacturers of diesel and gas

turbine systems to provide background.

Material used is not intended as an

endorsement of any particular device or

product. 1

Copyright Princeton University


Petroleum-Derived Fuels

Zhang et al (2009) Adapted from Speight , Dekker Inc 1991 2


Petroleum-Derived Fuels

Zhang et al (2009) Adapted from Speight , Dekker Inc 1991

Heavy Fuel Oils

3


What are Heavy Fuel Oils (HFOs)?

Speight, The Chemistry and Technology of Petroleum 4th ed, Taylor and Francis (2006)

From Wikipedia, RMK Heavy fuel oil

Conventional Definition:

• Refineries are typically designed for specific crude slates (crude types).

• Heavy fuel fraction is a function of the individual crude source, as well as

specific refinery optimization for producing the desired product slates

(generally driven by economic optimization).

HFO’s are the residual liquids after refining and upgrading blended

with mid-distillate fractions in a ratio sufficient to control sulfur/metals

content, viscosity, deposits, precipitation of heavy ends residing in

the residual fraction, and emissions.

More General Definition:

• Minimally processed crudes

• Pet-Coke slurries in conventional HFO (e.g. 30-50% PET in HFO)

• Coal slurries in conventional HFO (e.g. 85-90% coal/water slurries)

• Vacuum residuals-in-water emulsions (e.g. “OrimulsionTM“ concept)

4


Petroleum Crude Properties

from Cypraegean Neftegaz Ltd. (2013): http://www.cypraegean-neftegaz.com/

EIA Archive (2012); http://www.eia.gov/todayinenergy/detail.cfm?id=7110

Farhat et al (2007) Pet Sci Tech 20 633 654Goldmeer et al (2014) ASME Turbo Expo GT2014-25351

Arabian Crudes

Distillation properties

5


Petroleum Crude Properties

from Cypraegean Neftegaz Ltd. (2013): http://www.cypraegean-neftegaz.com/

EIA Archive (2012); http://www.eia.gov/todayinenergy/detail.cfm?id=7110

Farhat et al (2007) Pet Sci Tech 20 633 654Goldmeer et al (2014) ASME Turbo Expo GT2014-25351

Arabian Crudes

Distillation properties

6

Liquid Phase Cracking


HFO Production from Refining

7

VRO

RFO

Distillates


HFO Production from Refining

8

VRO

RFO

DistillatesPet coke


HFO Utilization

Liquid Residue/RFO

Distillates

HFODe-watering/particulate removal

(cat fines, etc.)

Centrifuging/water washing)

(Homogenization)

Bunkering

Blending (and later co-mingling) => fuel

stratification/instability

Contaminants =>

deposits, filter clogging,

corrosion, erosion

Sludge,

contaminated water

Energy Conversion

System

Design and Operation

Emissions

After

treatment

De-emulsifiers,

dispersants,

combustion

improvers, ash

modifiers

Urea, for SCR NOx

removal

PM2.5, S removal

Multi-Fuel Use High

Efficiency

Turndown Ratio

Durability

Maintenance

NOx/C/Ash

emission

9

Power Generation/Marine

Application

Power Generation/Marine

Application

Crude


Marine Diesel EmissionsInternationally regulated by the International Marine Organization (IMO: United Nations)

http://maritimecyprus.com/2014

Existing Emission Control Areas

AreaPollutant(s)

Controlled

Date

Adopted Entered into Force

Baltic Sea SOx 1997 2005

North Sea SOx 2005 2006

North American ECA,

including most of US

and Canadian coast

NOx, SOx, &

PM2010 2012

US Caribbean ECA,

including Puerto Rico

and the US Virgin

Islands

NOx, SOx, &

PM2011 2014

MARPOL Annex VI NOx Emission Limits

TierShip construction

date on or after

NOx Limit, g/kWh

n < 130 130 ≤ n < 2000 n ≥ 2000

I 2000 17.0 45 · n-0.2 9.8

II 2011 14.4 44 · n-0.23 7.7

III† 2016* 3.4 9 · n-0.2 2.0

Notes:

† Tier III standards apply only in NOx ECAs; Tier II controls apply outside NOx ECAs

* subject to a technical review to be concluded in 2013 this date could be delayed to 2021, regulation 13.10

Sulfur emission abatement options (each has pluses and minuses):• After-treatment aboard vessels (scrubber technologies, deploying now; disposal of waste)

• Increase production of very low sulfur fuels (refining intensive; increased CO2 emissions)

• LNG use in marine applications (LNG tankers ok, others very long term) 10

n = RPM

http://maritimecyprus.com/2014

http://transportpolicy.net/index.php?title=File:Imo_nox.png

http://transportpolicy.net/index.php?title=File:Imo_s.png


Marine Heavy Fuel Standards

Exxon-Mobil Marine Fuels specifications (Jan 2012)Emission Control Areas (ECA) limit the maximum sulfur in fuels

burned in their ports 4.5% m/m to as little as .10% as of 2015

inside an ECA. As of 2013, this is reduced to 3.5% (ISO) 8217ISO- 8217:2012 (E)

11

Exxon-Mobil Marine Fuels specifications (Jan 2012)

Test Unit Test method Limits Grade

ASTM IP ISO RMA 10 RMB 30 RMD 80 RME 180 RMG 180 RMG 380 RMG 500 RMG 700 RMK 380 RMK 500 RMK 700

Viscosity at 50°C mm²/s (cSt) D445 71 3104 max. 10.00 30.00 80.00 180.0 180.0 380.0 500.0 700.0 380.0 500.0 700.0

Density at 15°C kg/m³ D1298 160 3675 or 12185 max. 920.0 960.0 975.0 991.0 991.0 991.0 991.0 991.0 1010.0 1010.0 1010.0

CCAI – Calculated max. 850 860 860 860 870 870 870 870 870 870 870

Sulfur mass % D4294 336 8754, 14596 max. Statutory requirements

Flash point °C D93 34 2719 min. 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0 60.0

Hydrogen sulfide mg/kg – 570 – max. 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00 2.00

Acid number mg KOH/g D664 – – max. 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5

Total sediment aged mass % – 390 10307-2 max. 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10

Carbon residue, micro mass % D4530 398 10370 max. 2.50 10.00 14.00 15.00 18.00 18.00 18.00 18.00 20.00 20.00 20.00

Pour point Winter quality Summer quality

°C °C

D97 15 3016 D97 15 3016

max. 0 0 30 30 30 30 30 30 30 30 30 max. 6 6 30 30 30 30 30 30 30 30 30

Water volume % D95 74 3733 max. 0.30 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50

Ash mass % D482 4 6245 max. 0.040 0.070 0.070 0.070 0.100 0.100 0.100 0.100 0.150 0.150 0.150

Vanadium mg/kg – 501, 470 14597 max. 50 150 150 150 350 350 350 350 450 450 450

Sodium mg/kg – 501, 470 – max. 50 100 100 50 100 100 100 100 100 100 100

Aluminium + silicon mg/kg D5184 501, 470 10478 max. 25 40 40 50 60 60 60 60 60 60 60

Used lubricating oil Calcium + zinc Calcium + phosphorus

mg/kg mg/kg

– 501 or 470 – – 500 –

The fuel shall be free of ULO. – A fuel shall be considered to contain ULO when either one of the following conditions is met: – Calcium > 30 and zinc > 15 or calcium > 30 and phosphorus > 15


Wartsila X-92 Two Stroke

• IMO Tier II compliant operation

• IMO Tier III compliant with SCR technology; first such systems now being

produced and certified

• SOx scrubber technologies also available for both 2 and 4 stroke systems

https://www.wingd.com/en/products/waertsilae-x92/

http://www.wartsila.com/media/news/16-03-2015-first-wartsila-two-stroke-

engine-with-tier-iii-compliant-high-pressure-scr-produced-in-china-introduced

http://www.wartsila.com/media/news/10-03-2014-wartsila's-new-inline-

scrubber-system-design-lowers-cost-saves-space-and-eases-installation

12

https://www.wingd.com/en/products/waertsilae-x92/

http://www.wartsila.com/media/news/16-03-2015-first-wartsila-two-stroke-engine-with-tier-iii-compliant-high-pressure-scr-produced-in-china-introduced

http://www.wartsila.com/media/news/10-03-2014-wartsila's-new-inline-scrubber-system-design-lowers-cost-saves-space-and-eases-installation


Wartsila RT58-D Two Stroke

The photo is of a 5-cylinder Wärtsilä RT-flex58TD 2-stroke, low speed engine

produced at the Hudong Heavy Machinery Co Ltd (HHM) facilities fitted with an

SCR NOx control system. The SCR reactor was also manufactured by HHM.

This is the first SCR system that complies with the IMO’s Tier III regulations for

engine emissions of nitrogen oxide (NOx). To be installed in a new 22,000 dwt

multi-purpose vessel constructed at the Ouhua shipyard on behalf of China

Navigation Co (CNCo). News Release 3/15/15

https://www.wingd.com/en/products/waertsilae-rt-flex58/

http://www.wartsila.com/media/news/16-03-2015-first-wartsila-two-stroke-

engine-with-tier-iii-compliant-high-pressure-scr-produced-in-china-introduced13

https://www.wingd.com/en/products/waertsilae-rt-flex58/

http://www.wartsila.com/media/news/16-03-2015-first-wartsila-two-stroke-engine-with-tier-iii-compliant-high-pressure-scr-produced-in-china-introduced


Four-Stroke Multi-Fuel Power

http://www.wartsila.com/ 14

http://www.wartsila.com/


Challenges for HFO Use in Power Turbines

15Goldmeer et al (2014) ASME Turbo Expo GT2014-25351


Characteristic Combustion Times

Engine RPM SOI to

EVO

CA

Time

milli-seconds

50 130 430

100 130 216

1000 130 21.6

1500 130 14.4

• Available Combustion time depends on engine RPM

16

SOI – Start of injection

EVO – Exhaust valve Opening

CA- Crank Angle

Piston Engine Available Combustion Times

Gas Turbine Available Combustion Times

Less than ~10’s of milliseconds

• HFO characteristic reaction time includes both vapor-phase reaction and

heterogeneous burnout of the carbon remaining in the generated

particulate mass: includes both soot and coked liquid fuel (“cenospheres”)

• Burnout time is dependent on fuel injection/spray technology, physical and

chemical properties of the fuel

• Ash components generated through cenospheric burnout can result in

erosion/corrosion


Heavy Fuel Oil Organic Composition

Speight, The Chemistry and Technology of Petroleum 4th ed, Taylor and Francis (2006)

From Wikipedia, RMK Heavy fuel oil

• Chemical constituents in the heavy fuel are characterized by

SARA analysis:

• Saturates (n-alkanes, iso-alkanes, cyclo-paraffins)

• Aromatics (mono-, di-, and poly-aromatic hydrocarbons)

• Resins (constituent fractions of polar molecules

containing N, O, or S heteroatoms)

• Asphaltenes (similar to resins, but larger in “apparent”

molar mass and more polyaromatic in character); most

organo-metals, sulfur, nitrogen are in this fraction of the

original crude resource, further segregated by refining

17


Asphaltenes/Maltenes?

Asphaltenes – Mass fraction that precipitates by dilution of the sample with

an excess of an n-paraffin.

• Present major technical problems in all stages of oil production,

refining, heavy fuel utilization, and combustion (Sulfur, particulate

mass emissions; hot end corrosion/erosion).

• Increase viscosity of the fractions submitted to distillation in refineries

or during atomization in combustion systems

• Contribute to the formation of coke deposits during oil refining, in fuel

supply systems, injectors/atomizers

• Deactivate catalysts used in refining processes

• Foul fuel injectors and combustion systems

• Produce high-carbon-content particulates (”cenospheres”) in addition

to soot during the combustion process

• Asphaltene “macromolecules” exist as soluble dispersions in the

heavy fuel oil. Remain dispersed in dilution by an aromatic (e.g.

toluene)

Maltenes – Mass fraction left after removal of the Asphaltene fraction18


Refinery Vacuum Residual Properties

Stratiev et al (2016) Fuel 170 115-129) 19

Properties for a large variety of vacuum residual oils


Refinery Vacuum Residual Properties


Properties for a large variety of vacuum residual oils


C-7 De-asphalted Maltene Properties


Properties of the remaining de-asphalted vacuum residual oil fraction


Asphaltene “Structure”

“Island”

Monomeric structure, 500 < MW <1000 Da of 6 or

more aromatic- linked rings surrounded by aliphatic

groups that generally contain heteroatoms. Podgorski et al (2013) Energy Fuels 27 1268 1276

Figure from Applications Note: Asphaltenes (2014) Materials Design, Inc. www.materialsdesign.com.

Generally favored

in recent literature

22

http://www.materialsdesign.com/


Asphaltene “Structure”Proposed structure and aggregate characteristics a remain point of discussion

“Island”

Figures from Applications Note: Asphaltenes (2014) Materials Design, Inc. www.materialsdesign.com. 23

Immense literature on the molecular, nano-

aggregate, and cluster behavior of

“Asphaltenes” into “micellular structures”Monomeric structure, 500 < MW <1000 Da of 6 or



Generally favored




Asphaltene “Structure”Proposed structure and aggregate characteristics a remain point of discussion

“Island”

Figures from Applications Note: Asphaltenes (2014) Materials Design, Inc. www.materialsdesign.com. 24

• Asphaltene fraction definition is subject to the precipitating solvent choice and its

quantitative determination has indeterminate uncertainties.

• Asphaltene fraction has been historically considered as the primary

contributor to the formation of “coke” particulates (cenospheres) during the

combustion of HFO’s

Immense literature on the molecular, nano-

aggregate, and cluster behavior of

“Asphaltenes” into “micellular structures”Monomeric structure, 500 < MW <1000 Da of 6 or



Generally favored




Suspended Droplet Combustion

Dryer (1976) Proc Combust Ins 16 279-295

Some more recent studies using suspended droplets

Jacques et al (1977) Proc Combust Ins 16:307–319

Braide et al (1979) J Inst Energy 52:115–24.

Vallsenor and Garcia (1999) Fuel 78 933-944

Ikegami et al (2003) Fuel 82 293 304

Bartle et al (2011) Fuel 90 1113-1119

Bartle et al (2013) Fuel 835–842

Exemplar Methodology

16 mm backlighted high speed cine-sequence for an

atmospheric residual oil; Initial drop size, 450 microns;

4000 fps

25

Coke particulate


Suspended Droplet Combustion

Marrone et al (1984) Combust

Sci Tech 36 149-170

Dryer (1976) Proc Combust Ins 16 279-295

Qualitative approach to observe combustion behaviors, but

fiber presence can:

• Influence heat transfer to the liquid phase

• Provide nucleation sites for phase transformation

• Affect mass and morphology of final coke particulate

Isolated free droplet (combustion) experiments are preferred

over suspended studies for producing quantitative results.

Exemplar Methodology

16 mm backlighted high speed cine-sequence for an

atmospheric residual oil; Initial drop size, 450 microns;

4000 fps

26

Nucleation caused by filament


HFO Isolated Free Droplet Combustion

Strobe Backlighted Images

Consecutive 5000 fps frames

Marrone et al (1984) Combust Sci Tech 36 149-170

The moving droplets are uniform in initial size, isolated by tens of diameters with

gas/droplet relative velocity controlled. Experiment example: for 610 micron droplets

27



Cokin

g R

ea

ctio

ns


Organically soluble droplet

Organically insoluble cenosphere





28



Cokin

g R

ea

ctio

ns


Organically soluble droplet

Organically insoluble cenosphere





Burning droplets swell, eject gaseous jetting/(liquid

fragments), and production of organically insoluble

coke cenosphere occurs very late in the vapor phase

burn history.

29


Coke Formation Index (CFI) Apparatus

Isolated Drop Generator for non-Newtonian fluids

Green et al (1989) Rev Sci Instr 60 646

Urban and Dryer (1990) Proc Combust Ins 23 1437-1443 30


Isolated Free Droplet Results

Urban and Dryer (1990) Proc Combust Ins 23 1437-1443

31


Isolated Free Droplet Results

Katz (1987) MSE Thesis, Princeton University, MAE Report No. T-1795Urban and Dryer (1990) Proc Combust Ins 23 1437-1443

32

Nascent (uniform) cenospheres formed from 400 micron EPRI 2035 HFO droplets

Nascent

Cenospheres

quenched at

Vapor Phase

Burnout

(VPBO) point


Isolated Free Droplet Combustion Results

Nascent (uniform) cenospheres formed from 400 micron EPRI 2035 HFO droplets

5 micron thick micro-tombed slices through a cenosphere (EPRI 4013 HFO Fuel)

Katz (1987) MSE Thesis, Princeton University, MAE Report No. T-1795Urban and Dryer (1990) Proc Combust Ins 23 1437-1443

33

Nascent

Cenospheres

quenched at

Vapor Phase

Burnout

(VPBO) point


CFI and CDR for EPRI 4011 Fuel

CFI v Sampling location beyond Vapor

Phase Burnout Point (VPBO)

1990 Urban and Dryer (1990) ASME HTD 142 83-88

SEMs of cenospheres from 200 and 690 micron EPRI 4011 HFO fuel drops

200 micron690 micron

200 micron

690 micron

34


CFI and CDR for EPRI 4011 Fuel

CFI v Sampling location beyond Vapor

Phase Burnout Point (VPBO)

Particle Diameter v Drop Diameter

Thin Shell Model Prediction

1990 Urban and Dryer (1990) ASME HTD 142 83-88

200 micron690 micron

200 micron

690 micron

35

SEMs of cenospheres from 200 and 690 micron EPRI 4011 HFO fuel drops

PRINCETONMechanical and Aerospace EngineeringHFO Boiler Fuels from the Field

CFI Apparatus Results

Urban et al (1992) Proc Combust Ins 24 1357-1364 36

• CFI does not correlate with asphaltene content, CCR, or RCR!

• ρτ product is essentially the same with the exception of some special cases.


Hot Foil Coking Index (HFCI)

Figures from McElroy et al (1992) EPRI Report TR-100701

TM

Photo Courtesy of L Muzio

Fossil Energy Research Corp.

Laguna Hills, CA(HF-200 Manual 9/2003)

FERCo-HF200

Specifications (from the Manual)

• 15-20 mg Oil sample per run

• -Minimum of 3 runs per CI Measurement

• Repeatability within 10%< for CI<5%, using a

0.01 mg readability weighing scale (not

provided)

Similar heated foil methods described in Lawn et al (1987) 37


Hot Foil Coking Index (HFCI)

Figures from McElroy et al (1992) EPRI Report TR-100701

TM

Photo Courtesy of L Muzio

Fossil Energy Research Corp.

Laguna Hills, CA(HF-200 Manual 9/2003)

FERCo-HF200

Specifications (from the Manual)

• 15-20 mg Oil sample per run

• -Minimum of 3 runs per CI Measurement

• Repeatability within 10%< for CI<5%, using a

0.01 mg readability weighing scale (not

provided)

Similar heated foil methods described in Lawn et al (1987) 38

Heating rate makes a

difference

CFI and HFCI are

correlated

No correlation of

CFI/HFCI with other

metrics


Cenosphere to PM Emission Conversion

39

SEM Images of nascent

and partially oxidized

Cenosphere

~ 0.01-0.5 microns

~ 0.5-5 micronsFrom Walsh et al (1992) EPRI Report TR-100701

Schematic of single drop => PM evolution in HFO

Combustion

• Coke Formation Index (CFI/HFCI) estimates cenospheric (coke) residue yield accurately

• Coke diameter ratio (CDR) predictions, the coke mass and particle size distributions for HFO

sprays can be estimated accurately from small scale experimental methods



~ 0.01-0.5 microns



Combustion




• Coke particle burnout and evolution to PM are functions of ash components, structure and

fuel additives (which may partition into vapor and cenospheric particulates disproportionately)

• Aforementioned properties very much affect carbon emissions as well as hot-end

corrosion/erosion issues in energy conversion systems

• Other novel experimental approaches can examine cenospheric (coke) burnout properties

40



Cenosphere



~ 0.01-0.5 microns



Combustion




• Coke particle burnout and evolution to PM are functions of ash components, structure and

fuel additives (which may partition into vapor and cenospheric particulates disproportionately)

• Aforementioned properties very much affect carbon emissions as well as hot-end

corrosion/erosion issues in energy conversion systems

• Other novel experimental approaches can examine cenospheric (coke) burnout properties

EPRI Fuels Utilization Workshop reports through 1995 contain substantial developments on

semi-empirical models produced by Walsh and co-workers, McElroy et al, and others41



Cenosphere


Near-Term HFO Characterization Drivers

• Major evolution underway in transportation fuels and internal combustion engine (ICE) technologies using HFO fuels to increase fuel tolerance and substitution capabilities, optimize efficiencies, and reduce NOx, SOx, PM emissions

• The “inertia” of the recovery, refining, distribution system developed around petroleum liquid fuels and the numbers of legacy ground, air, and marine systems utilizing them are immense and it will likely take years and staggering capital investments to advance globally on the above.

• Petroleum, tar sands, and other fossil resources will remain the major source of transportation fuels for decades, perhaps most of this century. Substitution of these needs by alternative fuels from biomass, or LNG will make marginal impacts on these demands for a large fraction of this period

• The need for improvements in methods to reduce gaseous emissions and PM2.5 and for (innovative) carbon capture and sequestration (to address carbon emissions!) is certain.

• The possibility of using crudes and unconventional HFO’s directly for power generation/desalination applications in high efficiency/low emission devices can have major impacts on well-to-application overall energy efficiencies and carbon emissions.

• Developing engineering design tools to rapidly and inexpensively assess HFO combustion/emission related properties is of highest priority to evaluating fuels that can be accepted in existing equipment.

• These tools must reflect the combustion related behaviors associated with ever changing liquid fuel market, including crudes and HFO for both diesel and gas turbine stationary power and marine applications.

• Significant improvements in developing property-property relationships for each specific HFO fuel to vapor phase/cenospheric combustion behaviors (inclusive of burning rate, evolution of corrosive/erosive materials as a function of operating temperatures etc.) through advances in experiment are essential to building improved interpretive models for future engineering design applications. 42


AcknowledgementsI am very grateful to KAUST and the organizers of this work shop for inviting this presentation. My personal thanks as well to the many who contributed to the laboratory and my interests in HFO combustion for many years, beginning in 1974 to 1992. Irvin Glassman: for inspiring my interests in an academic career and applications-driven research, especially on heavy fuel combustion and water-fuel emulsions (my first research contract opportunity as a Co-Investigator).

Students:Glen Rambach (1977) MSE; Jim Gordan (1976-77) UG; Mark Cascia (1980) UG; Juan Lasheras (1981) PhD; Nicholas Marrone (1983) MSE; Loo Yap (1986) PhD; Charles Katz (1987) MSE; Robert Lawson (1989) MSE; Sidney Huey (1991) MSE; Nick Purzer (1994) UG

Professional Research Staff:Ian KennedyFumi TakahashiDave UrbanRichard Yetter

Technical Staff:Donald PeoplesPaul MichniewiczJoe SivoYolanda Stein

Research supporter on HFO combustion: US ERDA (U.S. Department of Energy) Electric Power Research InstituteElectric Power Technology Inc. Empire State Electric Energy Research CoConsolidated Edison Co. of New YorkOffice of Naval Research Mobil Research Corporation 43

Please make reference to this material as follows:

F.L. Dryer, “Combustion and Emissions Properties of

Heavy Oils”, 2016 Future Fuels Workshop, King Abdullah

University of Science and Technology (KAUST) Thuwal,

Saudi Arabia, March 7-9.

Combustion and Emissions Properties of Heavy Oils · Power Generation/Marine Application Power...

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