Abstract: The estimation method, such as GB/T 2429, ASTM D3338, ASTM D4529, and the precision methods (oxygen bomb method), such as GB/T 384 and ASTM D4809, are the commonly used methods for determination of net heat of combustion of jet fuel. The results indicated that because of the very different composition of coal direct liquefaction jet fuel from prtroleum-based jet fuels, the net heat of combustion by estimation methods were lower in varying degrees, especially the aniline point estimation methods including GB/T 2429 and ASTM D4529, which were obviously lower than other methods with the maximum difference of 0.3 MJ/kg, because the coal direct liquefaction jet fuel contains a mass fraction of 90% cycloalkane and almost no aromatic hydrocarbon, which are markedly different from the composition of petroleum-based jet fuel. Systematic errors exist in the GB/T 384 method, resulting in a result about 0.2 MJ/kg lower. As a consequence, ASTM D4809 method was recommended as the net heat of combustion test method for coal direct liquefaction jet fuel when high accuracy of data was required, while ASTM D3338 method was recommended under the conditions of no special requirement.

Key words: net heat of combustion, coal, direct liquefaction, jet fuel