Noncatalytic conversion of residuum in two‐stage coal liquefaction

Abstract

An experimental investigation was conducted to ascertain the contribution of thermal reactions in the hydroprocessing reactor of two‐stage liquefaction processes. Various solvent/residuum feedstocks were reacted in the absence of a catalyst at temperatures ranging from 655K to 728K. Detailed characterization of the composite and fractionated feedstock and product samples was performed to ascertain the extent of residuum conversion, heteroatom removal, and hydrogen rearrangement. The results showed that hydrogenation of the solvent portion of the feedstock neither enhances residuum conversion nor results in the transfer of hydrogen from the solvent to the residuum. Higher reaction temperatures also had little effect on the reactions involved. These results suggest that the conversion of residuum in the hydroprocessing reactor of two‐stage liquefaction processes must occur catalytically rather than thermally.

Recent Progress in the Direct Liquefaction of Coal

“…However, the high reactivity of coal is now recognized, as is the need to cap radicals quickly as they form; catalyst can speed the capping reactions. Catalyst also promotes hydrocracking of coal resid to distillable liquid (14).…”