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TRANSCRIPT
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