THERMAL STABILITY OF HYDROCARBON FUELS

Abstract : Research was conducted to: (1) develop a small scale jet fuel thermal stability tester capable of operation at fuel temperatures from 300 to 650 F with samples 1 qt or less in size, and (2) study the effects of storage on thermal stability performance of JP-6 grade jet fuels and establish causes (in terms of environmental factors and fuel composition) for any adverse results observed. Three potentially useful techniques were produced: (1) a recirculating-flow dynamic method measuring deposit insulating effects around a heated surface which requires 1000 ml fuel samples, (2) a static method measuring deposit insulating effects around a heated nickel wire which requires 150 ml fuel samples, and (=0 a static method based on ch nges in fuel light transmission characteristics after heating which requires only 5-ml fuel samples. The JP-6 storage stability invesigation (1 yr) showed that 3 out of 5 test fuels did deteriorate significantly after 26 wk at 110 F in terms of CFR fuel Coker rating, while a fourth fuel showed evidence of deterioration in one container only which is attributed to solids contamination.