Processes for Gasification of a Carbonaceous Feedstock
First Claim
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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:
- (a) supplying a carbonaceous feedstock, an oxygen-rich gas stream, an alkali metal gasification catalyst, and steam to a catalytic gasifier;
(b) reacting the carbonaceous feedstock in the catalytic gasifier in the presence of steam, the oxygen-rich gas stream and the alkali metal gasification catalyst, and under suitable temperature and pressure, to form a first gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide;
(c) optionally reacting at least a portion of the carbon monoxide and at least a portion of the hydrogen present in the first gas stream in a catalytic methanator in the presence of a sulfur-tolerant methanation catalyst to produce a methane-enriched first gas stream;
(d) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the first gas stream (or the methane-enriched first gas stream if present) to produce a second gas stream comprising a substantial portion of the methane from the first gas stream (or the methane-enriched first gas stream if present);
(e) optionally, if the second gas stream comprises hydrogen and greater than about 100 ppm carbon monoxide, reacting the carbon monoxide and hydrogen present in the second gas stream in a catalytic methanator in the presence of a methanation catalyst to produce a methane-enriched second gas stream; and
(f) recovering the second gas stream (or the methane-enriched second gas stream if present),wherein;
(i) at least one of step (c) and step (e) is present, and(ii) the second gas stream (or the methane-enriched second gas stream if present) is the methane product stream, or the second gas stream (or the methane-enriched second gas stream if present) is purified to generate the methane product stream.
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Abstract
The present invention relates to processes for preparing gaseous products, and in particular, methane via the catalytic gasification of carbonaceous feedstocks in the presence of steam and an oxygen-rich gas stream. The processes comprise using at least one catalytic methanator to convert carbon monoxide and hydrogen in the gaseous products to methane and do not recycle carbon monoxide or hydrogen to the catalytic gasifier.
195 Citations
17 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 a carbonaceous feedstock, an oxygen-rich gas stream, an alkali metal gasification catalyst, and steam to a catalytic gasifier; (b) reacting the carbonaceous feedstock in the catalytic gasifier in the presence of steam, the oxygen-rich gas stream and the alkali metal gasification catalyst, and under suitable temperature and pressure, to form a first gas stream comprising a plurality of gaseous products comprising methane, carbon dioxide, hydrogen, carbon monoxide and hydrogen sulfide; (c) optionally reacting at least a portion of the carbon monoxide and at least a portion of the hydrogen present in the first gas stream in a catalytic methanator in the presence of a sulfur-tolerant methanation catalyst to produce a methane-enriched first gas stream; (d) removing a substantial portion of the carbon dioxide and a substantial portion of the hydrogen sulfide from the first gas stream (or the methane-enriched first gas stream if present) to produce a second gas stream comprising a substantial portion of the methane from the first gas stream (or the methane-enriched first gas stream if present); (e) optionally, if the second gas stream comprises hydrogen and greater than about 100 ppm carbon monoxide, reacting the carbon monoxide and hydrogen present in the second gas stream in a catalytic methanator in the presence of a methanation catalyst to produce a methane-enriched second gas stream; and (f) recovering the second gas stream (or the methane-enriched second gas stream if present), wherein;
(i) at least one of step (c) and step (e) is present, and(ii) the second gas stream (or the methane-enriched second gas stream if present) is the methane product stream, or the second gas stream (or the methane-enriched second gas stream if present) is purified to generate the methane product stream. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification