Processes for Gasification of a Carbonaceous Feedstock
First Claim
1. A process for generating a plurality of gaseous products from a carbonaceous feedstock, and recovering a methane product stream, the process comprising the steps of:
- (a) supplying to an oxygen-blown gasifier (i) a first carbonaceous feedstock, (ii) an oxygen-rich gas stream and (iii) an aqueous stream comprising water and/or steam;
(b) at least partially combusting the first carbonaceous feedstock with the oxygen-rich gas stream in the oxygen-blown gasifier, under suitable temperature and pressure, to generate a first gas stream comprising hydrogen, carbon monoxide and superheated steam;
(c) introducing a second carbonaceous feedstock, a gasification catalyst and the first gas stream to a catalytic gasifier, the catalytic gasifier in communication with the oxygen-blown gasifier;
(d) reacting the second carbonaceous feedstock and the first gas stream in the catalytic gasifier in the presence of the gasification catalyst under suitable temperature and pressure to form a second gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide;
(e) optionally reacting at least a portion of the carbon monoxide and at least a portion of the hydrogen in the second gas stream in a catalytic methanator in the presence of a sulfur-tolerant methanation catalyst to produce a methane-enriched second gas stream;
(f) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the second gas stream (or the methane-enriched second gas stream if present) to produce a third gas stream comprising a substantial portion of the methane from the second gas stream (or the methane-enriched second gas stream if present);
(g) optionally, if the third gas stream comprises hydrogen and greater than about 100 ppm carbon monoxide, reacting carbon monoxide and hydrogen present in the third gas stream in a catalytic methanator in the presence of a methanation catalyst to produce a methane-enriched third gas stream; and
(h) recovering the third gas stream (or the methane-enriched third gas stream if present),wherein;
(i) at least one of step (e) and step (g) is present, and(ii) the third gas stream (or the methane-enriched third gas stream if present) is the methane product stream, or the third gas stream (or the methane-enriched third gas stream if present) is purified to generate the methane product stream.
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Accused Products
Abstract
The present invention relates to processes and continuous processes for preparing gaseous products, and in particular, methane via the catalytic gasification of carbonaceous feedstocks in the presence of steam. In one aspect of the invention, the processes comprise at least partially combusting a first carbonaceous feedstock with an oxygen-rich gas stream in an oxygen-blown gasifier, under suitable temperature and pressure, to generate a first gas stream comprising hydrogen, carbon monoxide and superheated steam; and reacting a second carbonaceous feedstock and the first gas stream in a catalytic gasifier in the presence of a gasification catalyst under suitable temperature and pressure to form a second gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide. The processes can comprise using at least one catalytic methanator to convert carbon monoxide and hydrogen in the gaseous products to methane and in certain embodiments do not recycle carbon monoxide or hydrogen to the gasifier.
217 Citations
16 Claims
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1. A process for generating a plurality of gaseous products from a carbonaceous feedstock, and recovering a methane product stream, the process comprising the steps of:
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(a) supplying to an oxygen-blown gasifier (i) a first carbonaceous feedstock, (ii) an oxygen-rich gas stream and (iii) an aqueous stream comprising water and/or steam; (b) at least partially combusting the first carbonaceous feedstock with the oxygen-rich gas stream in the oxygen-blown gasifier, under suitable temperature and pressure, to generate a first gas stream comprising hydrogen, carbon monoxide and superheated steam; (c) introducing a second carbonaceous feedstock, a gasification catalyst and the first gas stream to a catalytic gasifier, the catalytic gasifier in communication with the oxygen-blown gasifier; (d) reacting the second carbonaceous feedstock and the first gas stream in the catalytic gasifier in the presence of the gasification catalyst under suitable temperature and pressure to form a second gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide; (e) optionally reacting at least a portion of the carbon monoxide and at least a portion of the hydrogen in the second gas stream in a catalytic methanator in the presence of a sulfur-tolerant methanation catalyst to produce a methane-enriched second gas stream; (f) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the second gas stream (or the methane-enriched second gas stream if present) to produce a third gas stream comprising a substantial portion of the methane from the second gas stream (or the methane-enriched second gas stream if present); (g) optionally, if the third gas stream comprises hydrogen and greater than about 100 ppm carbon monoxide, reacting carbon monoxide and hydrogen present in the third gas stream in a catalytic methanator in the presence of a methanation catalyst to produce a methane-enriched third gas stream; and (h) recovering the third gas stream (or the methane-enriched third gas stream if present), wherein;
(i) at least one of step (e) and step (g) is present, and(ii) the third gas stream (or the methane-enriched third gas stream if present) is the methane product stream, or the third gas stream (or the methane-enriched third gas stream if present) is purified to generate the methane product stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16)
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10. The process of clam 1, wherein the methane product stream is a pipeline-quality natural gas.
Specification