Coal/Oil Coprocessing Using Syngas
Yuan C. Fu, Kenichi FUJIYA, Fumiaki TANAKA, Makoto AKIYOSHI
Coal and model compounds were hydrogenated and desulfurized in the presence of petroleum solvents and catalyst under coprocessing condition by using hydrogen or syngas (H2+CO) with steam in place of hydrogen. The catalysts used include NiMo, CoMo, synthetic pyrite and ZnCl2 catalysts. In general, the catalyst activities are somewhat lower with the use of syngas than with hydrogen. Nickel molybdate and cobalt molybdate catalysts impregnated with potassium carbonate, however, exhibited good activities for coal conversion as well as hydrogenation and desulfurization of model compounds with the use of syngas. Better results were obtained at a mild temperature of 400°C for the coprocessing of coal with petroleum solvents using syngas.
It was observed, with the solvents containing decalin, that decalin underwent dehydrogenation and isomerization, and that the extent of hydrodesulfurization increased with the increase of trans/cis ratio of the remaining decalin after the reaction. The addition of or 1-methylnaphthalene with decalin in the solvent mixtures increased the extent of conversion even though these compounds are nonhydrogen donors, suggesting that these compounds could be acting as hydrogen shuttlers to transfer hydrogen from decalin to coal or model compounds.