490 Gas Turbine Combustion: Alternative Fuels and Emissions, Third Edition
physical properties, such as viscosity, bulk modulus, specic heat, and ther-
mal conductivity, were typical of conventional jet fuels.
Harrison and Zabarnick [60] performed the thermal stability analysis
and Figure 10.21 shows the results using a quartz crystal microbalance. The
dynamic viscosity of conventional and synthetic fuels at low temperature is
shown in Figure 10.22. Finally, the volume elastomer swell for nitrile rubber
o-rings (Parker N-602-214) was also measured and plotted in Figure 10.23.
Table 10.7 shows the properties of bio-based synthetic parafnic kerosine.
Essentially, the properties of HRJ biofuels are indistinguishable from FT
synthetic parafnic kerosine. Therefore, the blending issues for HRJ (50/50)
biofuels are also similar, namely, density, aromatic content, and GHG footprint.
At present, not much information is available on the t-for- purpose proper-
ties (lubricity, dielectric strength, cetane number), combustion operability
and emissions, material compatibility, and blending issues.
Goodger [1] has plotted composite plots of the fuel properties of conven-
tional fuels, biofuels, and alcohols. Figure 10.24 shows fuel density and
Figure 10.25 shows kinematic viscosity as a function of fuel temperature.
Finally, Figure 10.26 shows the variation of net specic energy with fuel
density.
10.9.4 Combustion and emissions Performance
10.9.4.1 Fischer–Tropsch Fuels
Moses and Roets [59] report engine and combustor performance tests as
follows:
Engine endurance•
Low-temperature atomization•
TABLe 10.6
Properties of Conventional JP-8, Synthetic FT, and JP-8/FT (50/50) Blend Fuels
Property JP-8 Min JP-8 Max FT
a
(100%) FT
a
/JP-8 (50/50)
Aromatics (vol %) -- 25.0 0.0 6.8
Total sulfur (wt%) -- 0.30 0.0 0.046
Flash point (°C) 38.0 -- 45.0 55.0
Freeze point (°C) --- –47.0 –51.0 –50.0
Viscosity at –20°C (cSt) -- 8.0 4.9 4.8
Heat of comb (Btu/lb) 18,400 -- 18,978 18,686
Hydrogen content (wt%) 13.4 -- 15.4 14.6
Density (kg/L at 15C) 0.775 0.840 0.756 0.781
JP-8 specication update
Note: Denition to include coal, biomass, and natural gas via Fischer–Tropsch; -- blend
instructions for petroleum and nonpetroleum; -- reference MIL-handbook for “t-
for-purpose” properties. Effect of these property nonconformities under evaluation.
a
Syntroleum synthetic JP-8 (S-8).