Manufacture of Hydrogen from Fossil Resources in the Future Catalytic Gasification of Coal and Residual Oils

Abstract

Hydrogen has been manufactured mostly by steam reforming or partial oxidation of naphtha or natural gas. Hydrogen demand in chemical industry will increase at least for coming several decades. In the respect of effective utilization of fossil resources, coal and residual oils in addition to light petroleum fractions will be required to be feedstocks for hydrogen production. Many coal gasification processes have been developed, especially since the energy crisis 1973. The manufacture of hydro-gen from residual oils has been industriallized by thermal partial oxidation as in Shell and Texaco processes. For the future technology for hydrogen production by the gasi-fication of coal and residual oils, catalytic processes are expected as done in most chemical industries. This review describes the fundamental researches on the catalysis in the gasification of coal and residual oils, optimistcally applicable to fulfiill this expectation.Available information most directly relevant to catalysis of coal gasification has been obtained only within the last several years. As in the gasification of graphite or coke studied since 1920s, substances of basic nature like alkali salts are shown to be effective for coal gasification. The method of catalyst addition is very important to coal gasification processing. For the gasification of residual oils, nickel catalysts are as effective as for the fasification of light petroleum fractions. For residual oil proces-sing, however, a combination of the use of sulfur scavengers, properly designed reactor, and catalyst regeneration may be required as a final solution.