RELATIONSHIP BETWEEN SURFACE-ACIDITY AND LIQUEFACTION YIELD OF HYDROTREATING CATALYSTS

Abstract

Alaskan Usibelli coal was liquefied in naphthalene or tetralin under 13.78 MPa hydrogen pressure using six commercial hydrotreating catalysts of varying physical properties: Amocat 1A, HDN-30, HDN-60, Shell 317, Shell 324 and Amocat 1C. Also, stepwise thermal desorption (STD) of pyridine was carried out under chromatographic conditions to measure the amount of acid and the strength distribution on each catalyst, to relate the catalyst activity with the solid surface acidity. Comparing the results of coal liquefaction efficiency with the acidity measurements of six hydrotreating catalysts, it appears that weak acidity, which can provide reversible adsorption sites for reactants and products of catalytic reactions, is very important to improve liquefaction yield. The results showed that with the commercial hydrotreating catalyst, and having the same metals (Ni/Mo) on the surface, the catalytic activity for coal liquefaction correlated well with both the weak catalyst acidity and the pore volume in 30-200 angstrom diameter pores.