Patent ID: 8748687

Claim:
A process for generating a methane-enriched raw product gas stream from a non-gaseous carbonaceous material, the process comprising the steps of: (a) supplying to a hydromethanation reactor (1) a carbonaceous feedstock derived from the non-gaseous carbonaceous material, (2) a hydromethanation catalyst, (3) a superheated steam stream and (4) an oxygen-rich gas stream comprising steam, wherein the hydromethanation reactor comprises a fluidized bed having a upper portion above a lower portion, and wherein the superheated steam stream and the oxygen-rich gas stream are introduced into the lower portion of the fluidized bed; (b) reacting a portion of the carbonaceous feedstock in the hydromethanation reactor in the presence of hydromethanation catalyst, carbon monoxide, hydrogen and steam, at a target operating temperature at least about 1000° F. (about 538° C.) to about 1500° F. (about 816° C.), to produce a methane-enriched raw gas and a solid by-product char, wherein the methane-enriched raw gas comprises methane, carbon monoxide, hydrogen, carbon dioxide, hydrogen sulfide, steam, heat energy and entrained fines, and wherein the methane-enriched raw product stream comprises at least 50 mol % methane plus carbon dioxide (based on the moles of methane, carbon dioxide, carbon monoxide and hydrogen in the methane-enriched raw product stream); (c) reacting a portion of the carbonaceous feedstock with oxygen to produce carbon monoxide, hydrogen and heat energy; and (d) withdrawing the methane-enriched raw gas from the hydromethanation reactor as the methane-enriched raw product gas stream, wherein: (i) the reaction of step (b) predominates in the upper portion of the fluidized bed; (ii) the reaction of step (c) predominates in the lower portion of the fluidized bed; (iii) the reaction of step (b) has a syngas demand, a heat demand and a steam demand; (iv) the syngas demand and the heat demand are substantially satisfied by the reaction of step (c); (v) the steam demand is substantially satisfied by steam in the superheated steam stream and the oxygen-rich gas stream, and steam generated from the carbonaceous feedstock; and (vi) the superheated steam stream, the oxygen-rich gas stream, the carbonaceous feedstock and the hydromethanation catalyst are introduced into the hydromethanation reactor at a temperature below the target operating temperature of the reaction of step (b).