Kerosene freezing point

JP-5 F-44 High-flash/high-freeze-point, kerosene-based Naval carrier aircraft fuel will not corrode copper and will not emulsify with salt water... 

The increase in fuel viscosity with temperature decrease is shown for several fuels in Figure 9. The departure from linearity as temperatures approach the pour point illustrates the non-Newtonian behavior created by wax matrices. The freezing point appears before the curves depart from linearity. It is apparent that the low temperature properties of fuel are closely related to its distillation range as well as to hydrocarbon composition. Wide-cut fuels have lower viscosities and freezing points than kerosenes, whereas heavier fuels used in ground turbines exhibit much higher viscosities and freezing points. 

Operation of aircraft gas turbines on a wider cut than the 160—260°C fraction of cmde to expand avadabihty has been considered (24). Boiling range is limited at the low boiling end by flammabdity, ie, flash point, and at the high boiling end by low temperature needs, ie, freezing point. In the case of Jet A, a reduction of flash point from 38°C to 32°C would increase yield by 17% an increase in Jet A1 freezing point to —40°C would add about 25% to the kerosene pool. 

The freezing point of kerosene is not of the same importance as the freezing point of aviation fuel (Chapter 6) but deserves mention because of its influence on kerosene use. 

Industrial oleic acid Fatty acid mixture, oleic acid Class A organic acid 95 % class B organic acid 92-95 % Acid value 175-210, Iodine value 80-105, Moisture content 0.5 % Freezing point Class A <10 °C Class B 16 °C Class B 34 °C Blend with kerosene with a proportion of 1 1 or 1 2, or mixed, or emulsified with water... 

Kerosene is a middle distillate with a boiling range of about 160-270 °C that finds considerable use as jet fuel. The most critical property of jet fuel is the freeze point as the temperature may reach —50°C at flight altitudes of 10000 m. Kerosene vdth less-critical specifications is used worldwide in lighting, cooking, and heating. 

Throughout the world, specification DERD-2482, which is an Eastern Hemisphere kerosene is used almost exclusively (1956), but some fiirlines require a freeze point of — 50°F rather than — 40 F. 

The freeze point is the temperature at which the hydrocarbon liquid solidifies at atmospheric pressure. It s an important property for kerosene and jet fuels, because of the very low temperatures encountered at high altitudes in jet planes. One of the standard test methods for the freeze point is ASTM D4790. 

Jet fuel is kerosene-based aviation fuel. It is medium distillate used for aviation turbine power units and usually has the same distillation characteristics and flash point as kerosene. Jet fuels are manufactured predominately from straight-run kerosene or kerosene-naphtha blends in the case of wide cut fuels that are produced from the atmospheric distillation of crude oil. Jet fuels are similar in gross composition, with many of the differences in them attributable to additives designed to control some fuel parameters such as freeze and pour point characteristics. For example, the chromatogram (Figure 27.4) of a commercial jet fuel (Jet A) is dominated by GC-resolved n-alkanes in a narrow range of n-C-j to n-Cig with maximum being around n-Ci. The UCM is well dehned. 

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