Biomedical implications of altered product composition in advanced coal liquefaction processes

Abstract

Chemical and toxicologic characteristics of direct coal liquefaction materials are highly dependent upon the specific process operations by which the coal liquids were produced, including, in particular, those that affect boiling point range and degree of hydrogen incorporation. Recent advances in direct coal liquefaction technology, such as the use of catalytic hydrogenation, reduced liquefaction severity and lowering the upper temperature cut point for the distillation of fuels, have resulted in products with higher hydrogen-to-carbon ratios and lower heteroatom content. These higher-quality fuels tend to be less mutagenic and carcinogenic in laboratory assays than earlier coal liquefaction products. It is likely that application of postproduction hydrotreatment, as well as restriction of upper distillation temperature, for coal-based fuel products could result in materials that exhibit mutagenic or carcinogenic activity which is no greater than that of their petroleum-derived counterparts.