Use of metal hydrous titanium oxide catalysts to enhance coal tar yield via hydropyrolysis

摘要

Catalytic hydropyrolysis experiments performed in this project on several US and UK coals have established that tar yields in excess of 70% (daf basis) and conversions (100%-char) in excess of 80% can be achieved from bituminous coals containing 80--84% dmmf carbon using hydrous titanium oxide (HTO) catalysts with low concentrations of active metals. Total conversion approaches the reactive maceral contents for these coals. Previously performed two-stage catalytic hydropyrolysis experiments have demonstrated that high yields of liquid products with high H/C ratios, low heteroatom contents, and a significant concentration of light naphtha can be achieved. The objectives of this research are to determine suitable methods for catalyzing the hydropyrolysis process and to investigate the reactions and mechanisms responsible for the high conversion of coal materials to distillable liquids via direct catalytic hydropyrolysis. Recently developed hydrous titanium oxide (HTO)-supported catalysts have received encouraging results in direct coal liquefaction applications. Results of hydropyrolysis experiment using Mo and Pd HTO catalysts coated directly onto the coal are presented here and compared with results from experiments using uncatalyzed coal samples and using a dispersed MoS(sub 2) catalyst. The effect of coal rank, active metals concentration, dispersion method, and metal type are discussed. 9 refs., 6 figs., 2 tabs.