Production of a clean methane-rich fuel gas from high-sulfur containing hydrocarbonaceous materials

摘要

This is an improved process for converting low-cost high-sulfur containing hydrocarbonaceous materials into a clean methane-rich gas stream which may be burned as a fuel without contaminating the atmosphere. A high-sulfur hydrocarbonaceous fuel is gasified by partial oxidation to produce a process gas stream which is cooled, cleaned and subjected to catalytic methanation over a sulfur-resistant catalyst comprising 0.8 to 10 atoms of an element selected from the group comprising Co, Cr, W or mixtures thereof per atom of an element selected from the group Mo, Ni, or mixtures thereof. The catalyst may be supported on a structure formed from Group III and IV elements e.g. alumina, silica stabilized alumina, zeolite. A distinct advantage of the subject process, is that the sulfur in the process gas stream is not removed prior to the methanation step. Rather, the sulfur is permitted to remain in the process gas stream in order to moderate the highly exothermic methanation reaction. After cooling and purification by removing one or more members of the group H2, CO, H2O, CO2, COS, H2S, Ar, and N2, the resulting methane-rich gas stream comprises about 10 to 95 mole % CH 4. Optionally, the CH4 content of said methane-rich gas stream may be increased to about 98 mole % or more by the additional steps of water-gas shift conversion, catalytic methanation, cooling, drying and CO2 removal. The product gas would then have a gross heating value of about 1000 BTU/SCF.