Cryogenic process for separating synthesis gas
AssigneeUnion Carbide Corporation
InventorThirtahalli A. Shenoy
Life of this patent
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Abstract
A cryogenic separation of a feed gas mixture comprising hydrogen, carbon monoxide and methane by partial condensation, in which the feed gas is partially cooled and condensed, then separated to form first gas and liquid fractions, the latter is separated into carbon monoxide product gas and methane product gas, and the first gas fraction is further cooled for additional partial condensation and separated into a hydrogen enriched gas fraction and a second carbon monoxide rich liquid.
Claims10
In the cryogenic separation of a gas mixture comprising hydrogen, carbon monoxide and methane by partial condensation in which the feed gas mixture is provided at super atmospheric pressure above about 300 psia and partially cooled to condense a first liquid fraction and recover a first gas fraction, the first liquid fraction is separated into a carbon monoxide product gas and methane product liquid, the first gas fraction is further cooled for additional partial condensation and separated into a hydrogen enriched gas fraction and a second carbon monoxide rich liquid, the improvement comprising:
- (a) treating said first liquid fraction so as to provide a carbon monoxide rich liquid feed for the carbon monoxide-methane separation;
- (b) further cooling the first gas fraction at about said super atmospheric pressure for said additional partial condensation and separating the same into a second liquid fraction and a second gas fraction as said hydrogen enriched gas;
- (c) rewarming said second gas fraction as said hydrogen enriched gas fraction by heat exchange initially with the further cooling first gas fraction and thereafter with the partially cooling feed gas mixture;
- (d) expanding said second liquid fraction to lower pressure between 20 psia and 130 psia, and separating the same into a third liquid fraction and a third gas fraction;
- (e) providing said third gas fraction at low super atmospheric pressure below about 50 psia;
- (f) providing a minor portion of a carbon monoxide rich liquid obtained from the cooled feed gas mixture after further cooling, at said low super atmospheric pressure of step (e) and combining the so-provided minor portion with the third gas fraction of (e) to form a recycle gas mixture;
- (g) rewarming said recycle gas mixture by heat exchange initially with the further cooling first gas fraction and thereafter with the partially cooling feed gas mixture;
- and (h) flowing at least a major portion of said third liquid fraction to the carbon monoxide-methane separation.
Dependencies are inferred from the claim text.