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US 8,999,020 B2Granted
Processes for the separation of methane from a gas stream
AssigneeGreatpoint Energy, Inc.
InventorsPattabhi K. Raman, Francis S. Lau, Earl T. Robinson
Life of this patent
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Abstract
Processes for the catalytic conversion of a carbonaceous composition into a gas stream comprising methane are provided. In addition, the processes provide for the generation of a hydrogen-enriched gas stream and, optionally, a carbon monoxide-enriched gas stream, which can be mixed or used separately as an energy source for subsequent catalytic gasification processes.
Claims20
A process for converting a carbonaceous feedstock into a plurality of gaseous products contained in a gas stream, and for separating hydrogen and methane from the gas stream, the process comprising the steps of:
- (a) supplying a carbonaceous feedstock to a gasification reactor, wherein the carbonaceous feedstock includes a carbon source selected from the group consisting of coal, petroleum coke, asphaltene, liquid petroleum residue, biomass and mixtures thereof;
- (b) reacting the carbonaceous feedstock in the gasification reactor in the presence of steam and a gasification catalyst and under suitable temperature and pressure to form a first gas stream comprising methane, hydrogen, carbon monoxide, carbon dioxide, and one or more additional gaseous by-products;
- (c) removing a substantial portion of the carbon dioxide and a substantial portion of the one or more additional gaseous by-products from the first gas stream to produce a second gas stream comprising methane, hydrogen, and optionally carbon monoxide;
- (d) at least partially separating hydrogen from the second gas stream to form a hydrogen-enriched gas stream and a hydrogen-depleted gas stream, wherein the hydrogen-depleted gas stream comprises methane, optionally carbon monoxide and up to about 4 mol % hydrogen;
- wherein, if the heating value of the hydrogen-depleted gas stream is less than 950 btu/scf (dry basis), and if the hydrogen-depleted gas stream comprises 1000 ppm or more of carbon monoxide:
- (1) at least partially separating carbon monoxide from the hydrogen-depleted gas stream to form (i) a carbon monoxide-enriched gas stream and (ii) a methane-enriched gas stream having a heating value of at least 950 btu/scf (dry basis);
- or (2) at least partially methanating the carbon monoxide in the hydrogen-depleted gas stream to form a methane-enriched gas stream.
4 more elements
A process for converting a carbonaceous feedstock into a plurality of gaseous products contained in a gas stream, and for separating hydrogen and methane from the gas stream, the process comprising the steps of:
- (a) supplying a first carbonaceous feedstock to a reactor;
- (b) at least partially combusting the first carbonaceous feedstock in the reactor in the presence of oxygen and under suitable temperature and pressure so as to generate (i) heat energy and (ii) a combustion gas stream comprising hydrogen, carbon monoxide, and carbon dioxide;
- (c) using the heat energy from the combustion of the first carbonaceous feedstock to generate steam;
- (d) introducing at least a portion of the steam, at least a portion of the combustion gas stream, a second carbonaceous feedstock and a gasification catalyst to a gasification reactor, wherein the second carbonaceous feedstock includes a carbon source selected from the group consisting of coal, petroleum coke, asphaltene, liquid petroleum residue, biomass and mixtures thereof;
- (e) reacting the second carbonaceous feedstock in the gasification reactor in the presence of steam and the gasification catalyst under suitable temperature and pressure to form a first gas stream comprising methane, hydrogen, carbon monoxide, carbon dioxide and one or more additional gaseous by-products;
- (f) removing a substantial portion of the carbon dioxide and a substantial portion of the one or more gaseous by-products from the first gas stream to produce a second gas stream comprising methane, hydrogen and optionally carbon monoxide;
- (g) at least partially separating hydrogen from the second gas stream to form a hydrogen-enriched gas stream and a hydrogen-depleted gas stream, wherein the hydrogen-depleted gas stream comprises methane, optionally carbon monoxide and up to about 4 mol % hydrogen;
- wherein, if the heating value of the hydrogen-depleted gas stream is less than 950 btu/scf (dry basis), and if the hydrogen-depleted gas stream comprises 1000 ppm or more of carbon monoxide:
- (1) at least partially separating carbon monoxide from the hydrogen-depleted gas stream to form (i) a carbon monoxide-enriched gas stream and (ii) a methane enriched gas stream having a heating value of at least 950 btu/scf (dry basis);
- or (2) at least partially methanating the carbon monoxide in the hydrogen-depleted gas stream to form a methane-enriched gas stream.
7 more elements
Dependencies are inferred from the claim text.