Process, including PSA and membrane separation, for separating hydrogen from hydrocarbons
AssigneeMembrane Technology and Research, Inc.
InventorsRichard W. Baker, Kaaeid A. Lokhandwala, Zhenjie He, Ingo Pinnau
Life of this patent
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Abstract
An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.
Claims15
A process for separating a stream comprising hydrogen, methane and a C3+ hydrocarbon into at least three streams of different composition, comprising the following steps:
- (a) passing the stream through a pressure swing adsorption unit, thereby producing a hydrogen-enriched product stream and a tail gas stream;
- (b) compressing and cooling the tail gas stream, thereby producing a condensed C3+ hydrocarbon stream and an uncondensed stream;
- (c) passing the uncondensed stream across the feed side of a membrane separation unit containing a rubbery polymeric membrane, having a feed side and a permeate side and being selectively permeable to methane over hydrogen, under conditions sufficient that the membrane exhibits a methane/hydrogen selectivity of at least about 2.5;
- (d) withdrawing from the permeate side a permeate stream enriched in methane and C3+ hydrocarbon compared with the uncondensed stream;
- (e) withdrawing from the feed side a residue stream enriched in hydrogen compared with the uncondensed stream.
A process for separating a stream comprising hydrogen, methane and a C3+ hydrocarbon into at least three streams of different composition, comprising the following steps:
- (a) passing the stream through a pressure swing adsorption unit, thereby producing a hydrogen-enriched product stream and a tail gas stream;
- (b) compressing and cooling the tail gas stream, thereby producing a condensed C3+ hydrocarbon stream and an uncondensed stream;
- (c) passing the uncondensed stream across the first feed side of a first polymeric membrane having a first feed side and a first permeate side, and being selectively permeable to C2+ hydrocarbons over hydrogen;
- (d) withdrawing from the first permeate side a first permeate stream enriched in C3+ hydrocarbons compared with the uncondensed stream;
- (e) withdrawing from the first feed side a first residue stream enriched in hydrogen compared with the uncondensed stream;
- (f) passing the first residue stream across the second feed side of a second rubbery polymeric membrane having a second feed side and a second permeate side and being selectively permeable to methane over hydrogen, under conditions sufficient that the membrane exhibits a methane/hydrogen selectivity of at least about 2.5;
- (g) withdrawing from the second permeate side a second permeate stream enriched in methane and C3+ hydrocarbon compared with the first residue stream;
- (h) withdrawing from the second feed side a second residue stream enriched in hydrogen compared with the first residue stream.
Dependencies are inferred from the claim text.