THE ROLE OF CATALYST AND SOLVENT IN COAL-LIQUEFACTION

Taiheiyo coal has been liquefied at 410, 430, 450 and 470-degrees-C with 1-methylnaphthalene (1-MN) or tetralin as vehicle and either with presence or absence of FeS2 catalyst. The roles of catalyst and solvent in the reaction were investigated by analyzing the liquid and solid products in detail. The liquefaction was considered to involve two types of reaction: very rapid reaction and the successive slow reaction. A recombination of radical intermediates to form tetrahydrofuran-insoluble fraction (THFI) seems to proceed during the former reaction stage and the resulted THFI showed lower reactivity for the secondary cracking. The successive degradations of residual oil and distillable fraction were observed during the latter reaction stage. Tetralin solvent suppressed both the formation of THFI and the secondary cracking of produced oil. The existence of the catalyst resulted in the suppression of recombination to a significant extent.