Composition of Current and Alternative Jet Fuels Nov 3, 2011 Tim Edwards, AFRL Russ White, API

Composition of Current and Alternative Jet Fuels

Nov 3, 2011

Tim Edwards, AFRLRuss White, API

2DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution

Bottom Line Up Front

• Approved and prospective alternative jet

fuels (either 100% or blends) will be

hydrocarbons very similar to current fuels

• Fuels are to be “drop-in” – no handling

changes

• Most notable differences reduce the health

effects of these fuels– Lower aromatics – Lower sulfur


Current Composition Limits in Jet Fuel Specifications

• Aromatics < 25 vol% by D1319

• Naphthalenes < 3 vol% by D1840 (not naphthalene)

• “Light ends” controlled by flash and T10

• “Heavy ends” controlled by freeze and T90

• Density spec (0.775-0.84) requires cycloparaffins and/or

aromatics

• Impurities indirectly limited by thermal stability

• Sulfur content limited

• Smoke point limits aromatics indirectly (naphthalenes

more directly)


Aromatics in JP-8

0

200

400

600

800

1000

0 2 4 6 8 10 12 14 16 18 20 22 24 26

PQIS data 2008

Num

ber

of s

ampl

es

Aromatics by D1319, vol %

avg 17.4+/- 2.7 vol%


Naphthalene Study

• Individual naphthalenes results reported in µg/mL; total naphthalenes in

volume % (convert to µg/mL by multiplying by 1.06x104)

•Large standard deviations in concentrations within fuel classes

•Consistent results between current study and previous World Survey fuels

•Highest naphthalene in jet fuels and F-76, lowest in motor diesel

•Highest total naphthalenes in F-76 diesel, lowest in motor gasoline

FuelNaphthalene

(µg/mL)

1-Methyl naphthalene

(µg/mL)

2-Methyl naphthalene

(µg/mL)

D1840 Total

naphthalenes (volume%)

D6379 Total

naphthalenes (volume %)

Jet 1530 ± 772 1520 ± 495 2360 ± 869 1.15 ± 0.38 1.33 ± 1.49

F-76 1590 ± 599 1690 ± 701 3010 ± 1505 4.05 ± 0.84 5.74 ± 1.21

Motor diesel 357 ± 241 563 ± 467 1050 ± 875 2.61 ± 1.01 3.19 ± 1.48

Motor gasoline 1480 ± 797 467 ± 319 1080 ± 733 0.42 ± 0.21 0.42 ± 0.23

Jet (World Survey) 1580 ± 1037 NA NA 1.23 ± 0.72 1.80 ± 1.00

NA= Not analyzed


Jet Compositional Space

aromatics

cycloparaffins

n- +

iso-

para

ffins

25% aromatic limit in D1655,D7566

25

50

75

Avg: 53 n/iso, 28 cyclo, 19 aroWorld Survey

• ASTM D2425 currently used


5 10 15 20 25 30

4597 Jet A

4598 Jet A

4599 Jet A

4600 Jet A

4626 Jet A

4658 Jet AC7

C11

C16

Limited by flash point Limited by freeze point

Jet GC-MS


GC X GC

naphthalenes

alkyl benzenes

• JP-8 (POSF 4751)• Aromatics separated by class and carbon number


Baseline Fischer-Tropsch Fuels

n-paraffins

• Form basis of Research Report to support specification

B-52, T-38

C-5, B-2, C-130, F-16, HH-60, T-6, A-10, RQ-4

C-17, B-1, F-15F-22, KC-135R


Sasol IPK/A Analysis

• Research Report to support specification based on similarity to petroleum jet


HRJs feedstock independent

C13 C14 C15

C12

C9

C8

C11

C10

jatropha/algae oil

jatropha oil

camelina oil

animal fat

Salicornia oil

F-T

Inte

nsity

(ar

bitr

ary

units

)

Time


SPK Compositional Space

cyclo-paraffins

iso-paraffins n-pa

raffi

ns

15% cyclo limit in D7566Sasol IPK

Shell SPKS-8

ARA

PSU

cam HRJ

tallow HRJ

Gevo


Fuels from Woody Biomass

• Focus of DOE Biomass program

• Can yield fuels of atypical composition “Sugars”

Lignin


Lignocellulosic Biomass

April 21, 2023

“Sugars”

“Pyrolysis Oil”

alcohols jet “alcohol-to-jet”

jet“direct fermentation” or“metabologic engineering”

gasification syn gas jet

Fischer-Tropsch

“SPK”

pyrolysisjet

upgrading

fermentation

catalysis

jet “catalytic renewable jet?”

“pyrolytic renewable

jet?”


Gevo Public Data


Summary

• Alternative aviation fuels will remain hydrocarbons,

but…– Specifications will add more composition constraints– Molecular weight range may narrow (but still be ~8-14)– Blend stocks with a small number of HCs may exist– Relative proportion of hydrocarbon classes may shift– Sulfur will decrease, relative to current average of ~700 ppm– Blend stocks with and without aromatics will be seen

• Health benefits of alternative fuels currently not being

given credit in evaluations of “drop-in” fuels


Turbine Engine Emissions

• AF, NASA, FAA supporting emissions

testing for alternative jet fuels– The “usual” – NOx, CO, UHC, SOx– Particulates to support SAE E31 ARP– VOC, HAPS to develop database

• Significant data on ground (AAFEX etc.)

• Bottom line – alternative jet fuels are

hydrocarbons, most emissions unchanged– Exception – particulates (soot), typically reduced


18

AFRL Turbine Engine Research Transportable Emissions Lab (TERTEL)

Instrument MeasurementCondensation Particle Counter(TSI 3022A)

Particle Number

Scanning Mobility Particle Sizer (TSI 3936)

Particle Size Distribution(D=4.0 - 570 nm)

Tapered Element Oscillating Microbalance (R&P 1105)

Particle Mass Concentration

FTIR Analyzer (MKS 2030) CO2, CO, NOx, SOx, HC speciesNDIR Analyzer (CA 602P) Diluted Sample CO2

Smoke Sampler & Reflectometer(Photovolt Instruments Inc. 577)

Smoke Number

LECO Carbon Analyzer (RC-412) Elemental/Organic CarbonFID Analyzer (CA 600) Total HydrocarbonsMulti-Angle Absorption Photometer Particle Mass Concentration


Emissions Collaboration

DC-8

AFRL EmissionsTrailer EPA

Missouri S&T

AEDC, NASA/GRCAerodyne

NASA/LaRC

• Emissions study conducted with multiple partners on modified NASA DC-8 (CFM56) – Jan ’09– Multiple FT fuel blends (Sasol, Shell, 50/50, & 100%)• Data reduction underway but clear PM reductions with FT fuel and blends



AAFEX I


• Higher impact at lower power

– Consistent with previous studies (e.g. T63, CFM56, T701C, TF33)

– Reduce HC aerosols– Reduce soot nuclei

• Increased role of paraffinic species on soot formation at higher power

AAFEX CFM56 Particle Number EI

1.00E+11

1.00E+12

1.00E+13

1.00E+14

1.00E+15

1.00E+16

0% 20% 40% 60% 80% 100%

Parti

cle

Num

ber

EI (

#/kg-f

uel)

Engine Setting

JP-8 R (27 Jan - 48 F) FT1 (28 Jan - 56 F) FT2 (30 Jan - 60 F)

Significantly lower particle number EI with FT fuels


AAFEX I (cont)


Ultralow Sulfur Jet Fuel

2009


Diesel Engine Evaluation with Alternative Fuels

•Similar engine performance (fuel conversion eff.) with JP-8, FT blend & diesel

•Higher engine exhaust temperatures (5-10%) with diesel at higher RPMs

•Slight reductions (5-10%) in engine BHP with JP-8 and FT blend

– Lower fuel density and limits in fuel delivery system

• Impact of JP-8 and FT blend on emissions dependent on engine and condition

•Highly variable particle number data

– Inherent non-continuous combustion in reciprocating engines

•Similar or lower smoke numbers with alt fuels

•Moderate reduction in PM mass

•Mostly lower CO (20-40%) and NOx (10-17%) emissions

– Trends agree with previous measurements in 6.5L diesel

•Technical paper to be included in IASH 2009 proceedings

Documents

Composition of Current and Alternative Jet Fuels Nov 3, 2011 Tim Edwards, AFRL Russ White, API