Production and Analysis of EDS Coal-Derived Middle Distillate Test Fuels from Hydrogenation at Three Levels of Severity

A series of coal-derived test fuels for compression ignition engines was prepared from Exxon Donor Solvent middle distillate, a representative alternative feedstock made from coal. This series will be used in experimental work for the Alternative Fuels Utilization Program of the U.S. Department of Energy. Processing included caustic extraction of phenolic compounds, hydrogenation to remove remaining heteroatoms (N, O, and S) and increase hydrogen content (from 10.9 M%), and nitrogen stripping to remove residual by-product gases and control the flash point. Operations at three degrees of hydrogenation severity yielded products with 11.9, 12.7, and 13.1 M% hydrogen. Characterizations included standard ASTM tests, instrumental methods for chemical composition (MS, NMR), and engine tests of ignition quality. Even though fuel density and hydrogen content were in the range of petroleum fuels, ignition quality was 29.0 to 38.2 cetane number which is low compared to cetane number for similar petroleum fuels.