Albert C. Frost

The simultaneous reactions of carbon monoxide and hydrogen on a nickel catalyst

Abstract Initial development studies, carried out under contract with the United States Department of Energy, have been completed on a two bed, two reaction step process concept (the COthane process), designed to convert CO from dilute industrial gas streams into pipeline quality natural gas. Preliminary runs with a simple CO/N2 feed showed that during the first reaction step of the conceptual process cycle, the CO both disproportionates and chemisorbs on the nickel catalyst surface, yielding CNi and CONi as stationary surface products and CO2 as an effluent product. During the second reaction step, steam reacts with CNi and CONi to form CH4 and CO2, a stream that can be readily upgraded to high quality natural gas. It was also found that hydrogen, instead of steam, could also be used for the second, methane-producing step. These preliminary results and supporting equilibrium calculations led to the expectation that hydrogen or water vapor in the feed stream would cause the premature formation and venting of CH4 during the first reaction step, with a subsequent loss of recoverable CH4 that could be formed during the second reaction step. However, the experimental data reported in this paper have shown that water in the process feed stream had only a negligible effect on the amount of CH4 that could be recovered during the second reaction step, and that hydrogen in the process stream actually raised the amount of CH4 that could be recovered during the second reaction step. These results are believed to have been caused by the relatively slow rate of the second reaction step, and the relatively fast rate of the CO + H2 ⇌ CNi (or C-Hx) + H20 reaction, at the low H2O and H2 partial pressures present in the process feed gas during the first reaction step.