Patent ID: 8728183
Filing Date: 2014-05-20
Classification: C01B,C10J,C10K,C10L,Y02P

Abstract:
1. A process for generating a plurality of gaseous products from a carbonaceous feedstock, and generating a methane product stream, the process comprising the steps of: (a) supplying a carbonaceous feedstock, an oxygen-rich gas stream, a hydromethanation catalyst and a steam stream to a hydromethanation reactor, the carbonaceous feedstock comprising a carbon content and a moisture content; (b) reacting a portion of the carbon content from the carbonaceous feedstock in the hydromethanation reactor in the presence of oxygen to produce carbon monoxide, hydrogen and heat energy; (c) reacting the carbonaceous feedstock in the hydromethanation reactor in the presence of carbon monoxide, hydrogen, steam and hydromethanation catalyst, at a temperature of at least about 700° F. (about 371° C.) to about 1500° F. (about 816° C.), to produce a methane-enriched raw product stream comprising methane, carbon monoxide, hydrogen, carbon dioxide and heat energy; (d) withdrawing the methane-enriched product stream from the hydromethanation reactor, 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); (e) introducing the methane-enriched raw product stream into a heat exchanger to recover heat energy and generate a cooled methane-enriched raw product stream; (f) using the heat energy recovered in step (e) to (1) superheat the steam stream prior to introduction into the hydromethanation reactor, and (2) generate a first process steam stream; (g) in the event that the molar ratio of hydrogen to carbon monoxide in the cooled methane-enriched raw product stream is less than about 3:1, optionally sour shifting a portion of the carbon monoxide in the cooled methane-enriched raw product stream to generate heat energy and a hydrogen-enriched treated product stream having a molar ratio of hydrogen to carbon monoxide of at least about 3:1; (h) optionally recovering heat energy from step (g), if present, wherein at least a portion of the recovered heat energy is utilized to generate a second process steam stream; (i) optionally reacting a portion of the hydrogen and at least a portion of the carbon monoxide in the cooled methane-enriched raw product stream (or the hydrogen-enriched treated product stream if present) in a catalytic methanator in the presence of a sulfur-tolerant methanation catalyst to produce a methane-enriched treated product stream; (j) optionally recovering heat energy from step (i), if present, wherein a least a portion of the recovered heat energy is utilized to generate a third process steam stream; (k) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the cooled methane-enriched raw product stream (or the hydrogen-enriched treated product stream, if present, or the methane-enriched treated product stream, if present) to produce a sweetened gas stream comprising a substantial portion of the hydrogen, carbon monoxide and methane from the cooled methane-enriched raw product stream (or the hydrogen-enriched treated product stream, if present, or the methane-enriched treated product stream, if present); (l) optionally separating a portion of hydrogen from the sweetened gas stream to produce a hydrogen-depleted sweetened gas stream comprising methane, hydrogen and carbon monoxide; (m) reacting carbon monoxide and hydrogen present in the sweetened gas stream (or hydrogen-depleted sweetened gas stream, if present) in a catalytic methanator in the presence of a methanation catalyst to produce heat energy and a methane-enriched sweetened gas stream; (n) recovering heat energy from step (m), wherein at least a portion of the recovered heat energy is utilized to generate a fourth process steam stream; and (o) recovering at least a portion of the methane-enriched sweetened gas stream as the methane product stream, wherein: