Abstract: A method for activating a hydrodesulfurization catalyst by passing a gaseous stream comprising carbon oxides, hydrogen, and sulfur-containing compounds into contact with the catalyst at a temperature from about 400.degree. to about 700.degree. F. until the outlet gaseous stream from the catalyst has a sulfur content substantially equal to the sulfur content of the inlet gaseous stream and thereafter increasing the temperature incrementally and continuing to contact the catalyst with the inlet gas stream until the sulfur content in the outlet gaseous stream is substantially equal to the sulfur content of the inlet gaseous stream after each incremental temperature increase.

Abstract: A method is provided wherein nickel molybdenum and cobalt molybdenum catalysts can be used in large scale sulfur hydrogenation reactors without runaway methanation and resulting exotherms while converting organic sulfur compounds to hydrogen sulfide in gas streams which contain significant quantities of carbon monoxide, carbon dioxide, and hydrogen.

Abstract: An improved method for removing sulfur compounds during coal gas methanation comprising removing essentially all carbon dioxide and hydrogen sulfide from synthesis gas, then adding carbon dioxide containing lower levels of sulfur back to the gas stream before feeding the mixture to a desulfurization reactor. Carbon dioxide, at levels above about 12 percent, will prevent high temperature methanation runaways in the hydrodesulfurization reactor, where a stream consisting essentially of hydrogen sulfide and methanation materials is produced, the lower level of hydrogen sulfide produced being removed by conventional methods before proceeding to methanation units. The carbon dioxide can be supplied either from an outside source or can be obtained from the synthetic natural gas after methanation.