Thermal and Catalytic Cracking Reactions of Coal Liquefaction Residues

Abstract

An about 30wt % of raw coal is discharged as a residue from vacuum distillation column in NEDOL coal liquefaction process. Effective utilization of this residue is important to improve profitability of this process. In the present report, pyrolysis and catalytic cracking reaction of four kinds of coal liquefaction residues were carried out by use of a TG apparatus and a GC with pyrolyzer under inert gas to obtain useful chemical compounds from residue. In the TG analysis, the maxmum weight decrease of each sample was observed at the heating rate of 5°C/min. The Illinois No.6 coal residue exhibited larger weight decrease than others. In flash pyrolysis in a GC with pyrolyzer, yields of light fractions, especially gaseous products (C₁-C₄) increased with increasing reaction temperature. The catalytic cracking reaction with a FCC cata-lyst showed that the yield of light fractions of the shorter retention time than naphthal-ene increased for all residues.