Application of Synthetic Diesel Fuels

“Future Fuels : Issues and Opportunties”

11th Diesel Engine Emissions Reduction Conference, Chicago, August 21-25, 2005

Paul Schaberg, Sasol Technology

Presentation Outline

Description of synthetic diesel fuel production processes

Description of synthetic diesel fuel properties

Overview of Sasol’s current GTL and CTL plans

Possible market introduction scenarios

Combustion and exhaust emissions with GTL diesel fuel and blends

Opportunities for engine optimisation

Summary and concluding remarks

Fischer-TropschSynthesis

Product UpgradingSyngas Production

Generic xTL Process

hydroprocessing

H2O

light gas

distillation

light gas

heavy fractionwaxFTBO feed

FTBOreturn

naphtha

diesel

jet/kero

carbonsource

oxygensource

steam

reformer / gasifier

syngas

FT reactor

conden-sate

(< C20 )

wax(> C20 )

coal gas oil biomass

Diesel Fuel Properties

Clear, odourless liquidHighly paraffinic(total aromatics < 1%, polycyclic aromatics < 0.05%)

Density ~ 770 g/lH/C ratio ~ 2.10 mol/molLHV ~ 43.8 MJ/kgCetane number > 70

Very low sulphur (< 1ppm)Good thermal stabilityDistillation range determined by:

Applicable specifications (T90, flash point, cold flow properties)Jet / kerosene production 100

150

200

250

300

350

400

6 8 10 12 14 16 18 20 22 24 26 28Carbon Number

Boi

ling

Poin

t (°C

)

n-Paraffins2-Methyl-i-paraffinsIBP constrained

by flash point

FBP constrained by T95 specification

Yield maximised with full boiling range diesel fuel

T95 ~ 360°C

CFPP ~ -20°C

Flash point~60°C~55°C

650

700

750

800

850

900

950

6 8 10 12 14 16 18 20 22 24 26 28Carbon Number

Den

sity

at 2

0°C

(g/l)

n-Alkyl Cyclo Hexanesn-Alkyl Benzenesn-Paraffins

European maximum and minimum limits

South AfricaSasol I and II160 000 bpdIn operation

ChinaSasol / Shenua / Ningxia

2 X 80 000 bpdFeasibility Stage

AustraliaSasolChevronStudy on GTL

opportunity progressing

NigeriaCNL / NNPC34 000 bpd

EPC contract awarded

QatarSasol / Qatar Petroleum

34 000 bpd (Oryx I)Under construction

IranSasol

Study on GTL opportunity progressing

USAEvaluating

Opportunities

Gas-to-Liquids

Coal-to-Liquids

QatarSasolChevron / Qatar Petroleum

65 000 bpd (Oryx II) - MOU130 000 bpd - LOI

+

Current GTL and CTL Plans

Oryx GTL, Qatar

34 000 bpd initial capacity, expansion to 100 000 bpdStartup end Q1 2006FT reactor

Mass = 2200 tonsHeight = 60mDiameter = 10m

Oryx 23,000 bpdFrance

610,000 bpd

CurrentSasol Chevron

projects 250,000 bpd

London bus fleet1,750 bpd

Globalautomotive diesel

market13,000,000 bpd

Europe3,500,000 bpd

WorldscaleGTL plant

100,000 bpd

EGTL 23,000 bpd

UK380,000 bpd Total GTL projects

under development750,000 bpd

Italy450,000 bpd

Germany540,000 bpd

GTL Diesel Relativity

Some Application Scenarios

Time

Volu

me

of s

ynth

etic

fuel

ava

ilabl

e

Refinery blendstock ->

premium diesel

Neat fuel -> niche market application

Refinery blendstock -> new premium diesel -> standard and optimised

engines

Neat fuel -> optimised engines

Conforms to current specification

Does not conform to current specification

New applications -> HCCI, FC

Refinery blendstock -> conventional

diesel

Exhaust emissions with GTL diesel fuel, conventional engines

-40-20

020406080

100

-20 -10 0 10 20 30 40NOx Reduction (%)

PM R

educ

tion

(%) Heavy Duty

Light Duty

Source : NREL SAE Paper 2003-01-0763

Typically obtain reductions in all regulated emissions (HC, CO, NOx, PM)Reductions in CO2 and other unregulated emissionsNOx and PM critical:

13% avg. NOx reduction26% avg. PM reduction

Passenger Car Emission Tests

Tests performed with a Mercedes E220 CDI (Euro 3) vehicle and engineNeat GTL diesel fuel and blends compared with sulphur-free EN590 diesel fuelAll calibration parameters kept constant during steady-state testsBlends showed disproportionate reductions in soot / PM in both vehicle and engine testsDisparity in NOx response between vehicle test and engine tests : non-optimal engine calibration for lower density, higher cetane fuels.

0

20

40

60

80

100

120

HC CO NOx PM CO2 FC

Rel

ativ

e Le

vel (

%)

EU Diesel50:50 EU-GTL DieselGTL Diesel

NEDC Vehicle emission tests

0

20

40

60

80

100

120

1 2 3 4 5Operating Point

Rel

ativ

e N

Ox

(%)

EU Diesel 80:20 EU-GTL50:50 EU-GTL GTL Diesel

Steady-state engine bench tests

Injection System Performance

Common-rail FIEInjection rates for the two fuels are similar at low loadsExpected deviation due to density difference is evident at higher loadsNo negative effects on operation of FIEBesides lower density, lower viscosity of GTL diesel fuel could to be influencing parameter

-100

102030405060

0 1 2 3 4Time (ms)

Inje

ctor

Flo

wra

te (g

/s)

GTL Diesel FuelEN590 Diesel Fuel

4000 min -1 , full loadP rail = 1560 bar

-5

0

5

10

15

20

25

30

0 1 2 3 4Time (ms)

Inje

ctor

Flo

wra

te (g

/s)

GTL Diesel FuelEN590 Diesel Fuel

2000 min -1 , 2 bar bmepP rail = 570 bar

Injection System Performance

Unit Injector FIEInjection rate for the GTL diesel fuel is lower than EN590 diesel fuel at low loadsDeviation at higher loads is smallerNo negative effects on operation of FIEBesides density, lower bulk modulus of GTL diesel fuel could be an influencing parameter

-10

0

10

20

30

40

50

60

0 1 2 3 4Time (ms)

Inje

ctor

Flo

wra

te (g

/s)

EN590 Diesel Fuel

GTL Diesel Fuel

4000 min -1 , full load

-5

0

5

10

15

20

25

30

0 1 2 3 4Time (ms)

Inje

ctor

Flo

wra

te (g

/s)

EN590 Diesel

GTL Diesel Fuel

2000 min -1 , 2 bar bmep

Combustion Properties

Combustion processes of GTL diesel fuel have been compared to EN590 diesel fuel, using both classical and advanced in-cylinder diagnosticsAs expected, differences in ignition properties and soot formation have been observedDifference in ignition delay is a non-linear function of cylinder pressure and temperature (load).

-20

0

20

40

60

80

100

-40 -20 0 20 40 60Crank Angle (° ATDC)

Cyl

inde

r Pre

ssur

e (b

ar)

RO

HR

(kJ/

m3 .d

eg)

EU DieselGTL Diesel50:50 EU-GTL80:20 EU-GTL

18° ATDC, 2000 min-1, 7 bar bmep

EU Diesel GTL Diesel

1600 min-1, 3.3 bar bmep

Opportunities for Optimisation

35% reduction in both soot and NOx through software optimisationHardware optimisation (combustion system, FIE) is expected to compliment this furtherEnd result could be reduced requirement for exhaust gas aftertreatment, i.e. cost saving

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140Relative NOx (%)

Rel

ativ

e So

ot (%

) EU Diesel

80:20 EU-GTL Diesel Blend

50:50 EU-GTL Diesel

Blend

GTL Diesel

35% Potential Reduction in both NOx and Soot with

GTL Diesel fuel

NOx (g/km)

PM (g

/km

) Software optimisation

Hardware + software optimisation

with DPF

Summary

Dawn of the synthetic fuels ageSynthetic fuels technology is enabling the production of clean, very high quality fuels from diverse feedstocks, including non-petroleum and renewable feedstocks

Plans for a significant number of large scale GTL production plants have been announced, the first of which will start up in 2006

Relative synthetic fuel volumes will be small for many years –global impact will be small, but regional impact can be significant

Developing an understanding of the combustion and emissions properties of synthetic diesel fuels in order to:

Ensure problem-free operation in both neat and blended form

Quantify the benefits

Understand opportunities for engine optimisation

Understand the opportunities for future combustion systems