Comparison of alkanes released from a bituminous coal via hydropyrolysis and low temperature hydrogenation

Abstract

The use of dispersed sulphided molybdenum catalysts significantly increases the yields of DCM-soluble material from both hydropyrolysis (520 °C) and low temperature (350 °C) hydrogenation of coals. The detailed molecular compositions of the alkanes obtained via hydrogenation and hydropyrolysis with and without catalyst have been determined by g.c.-m.s. for a UK bituminous coal (Gedling). A similar range of compounds was found in each case, but the distributions varied in small, but significant ways. The relative abundance of n-alkanes increases with increasing conversion but maturity parameters based on ratios of hopane and sterane stereoisomers have lower (less mature) values. This is proposed to arise from the catalytic-induced cleavage of weak heteroatom bonds, resulting in the release of biological marker compounds which were incorporated into the macromolecular matrix through functional groups present in the original biolipids and which have retained their original biological configuration.