Hydromethanation of a carbonaceous feedstock
First Claim
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1. 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).
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Abstract
The present invention relates to a steam-integrated and heat-integrated process for preparing gaseous products, and in particular methane and/or other value added gaseous products such as hydrogen, via the hydromethanation of non-gaseous carbonaceous feedstocks in the presence of steam, carbon monoxide, hydrogen, oxygen and a hydromethanation catalyst.
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Citations
21 Claims
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1. A process for generating a methane-enriched raw product gas stream from a non-gaseous carbonaceous material, the process comprising the steps of:
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(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). - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification