Treatment of ammonia synthesis purge gas
AssigneePetrocarbon Developments Limited
InventorsWieslaw H. Isalski, Terence R. Tomlinson
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Abstract
A process is disclosed for recovering hydrogen from an ammonia synthesis plant comprising (a) cooling a high pressure stream of said purge gas to a sub-ambient temperature at which substantially all of the methane and argon contained in said purge gas stream and a portion of the nitrogen condense, (b) expanding liquid and vapor components of the cooled high pressure stream to an intermediate pressure, (c) phase separating liquid and vapor components of the cooled and expanded purge gas stream, (d) expanding separated liquid component from step (c), and (e) heating expanded separated liquid component from step (d) and separated vapor component from step (c) in heat exchange with said high pressure stream of purge gas to cool the latter.
Claims13
A process for the recovery of hydrogen from purge gas comprising hydrogen and nitrogen and impurities including methane and argon from an ammonia synthesis plant which comprises:
- (a) cooling a high pressure stream of said purge gas to a sub-ambient temperature at which substantially all of the methane and argon contained in said purge gas stream and a portion of the nitrogen condense,
- (b) expanding liquid and vapour components of the cooled high pressure stream to an intermediate pressure,
- (c) phase separating liquid and vapour components of the cooled and expanded purge gas stream,
- (d) expanding separated liquid component from step (c), and
- (e) heating expanded separated liquid component from step (d) and separated vapour component from step (c) in heat exchange with said high pressure stream of purge gas to cool the latter.
A process according to any preceding claim in which the liquid and vapour components of the cooled high pressure stream are expanded to an intermediate pressure which is from 20 to 40 bar lower than the pressure of the high pressure stream.
Dependencies are inferred from the claim text.