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US 6,190,536 B1Granted
Catalytic cracking process
AssigneeMembrane Technology and Research, Inc.
InventorsKaaeid A. Lokhandwala, Richard W. Baker
Life of this patent
Estimating the term…
Abstract
Processes and apparatus for providing improved catalytic cracking, specifically improved recovery of olefins, LPG or hydrogen from catalytic crackers. The improvement is achieved by passing part of the wet gas stream across membranes selective in favor of light hydrocarbons over hydrogen.
Claims53
A catalytic cracking process, comprising the following steps:
- (a) cracking a hydrocarbon feedstock;
- (b) fractionating the hydrocarbon product of step (a) to produce at least one liquid stream and an overhead vapor stream;
- (c) cooling at least a part of the overhead vapor stream, thereby producing an overhead liquid stream and a wet gas stream;
- (d) compressing at least a part of the wet gas stream;
- (e) separating the compressed wet gas stream into a hydrocarbon liquid portion and a vapor portion;
- (f) passing at least a part of the vapor portion through at least one absorption step to absorb C3+ hydrocarbon components, thereby producing a lighter vapor portion;
- (g) passing at least a part of the lighter vapor portion as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C2+ hydrocarbons over hydrogen;
- (h) withdrawing from the permeate side a permeate stream enriched in C2+ hydrocarbons compared with the feed gas;
- (i) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas.
6 more elements
A catalytic cracking process, comprising the following steps:
- (a) cracking a hydrocarbon feedstock;
- (b) fractionating the hydrocarbon product of step (a) to produce at least one liquid stream and an overhead vapor stream;
- (c) cooling at least a part of the overhead vapor stream, thereby producing an overhead liquid stream and a wet gas stream;
- (d) compressing at least a part of the wet gas stream;
- (e) separating the compressed wet gas stream into a hydrocarbon liquid portion and a vapor portion;
- (f) passing at least a part of the vapor portion through at least one absorption step to absorb C3+ hydrocarbon components, thereby producing a lighter vapor portion;
- (g) compressing and then cooling at least a part of the lighter vapor portion;
- (h) separating the compressed, cooled lighter vapor portion into a recovered liquid stream and an uncondensed stream;
- (i) passing the uncondensed stream as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C2+ hydrocarbons over hydrogen;
- (j) withdrawing from the permeate side a permeate stream enriched in C2+ hydrocarbons compared with the feed gas;
- (k) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas.
8 more elements
A process for treating a gas stream, containing hydrogen and C3+ hydrocarbons, from a catalytic cracking plant, comprising the steps of:
- (a) contacting the gas stream with a hydrocarbon liquid such that C3+ hydrocarbons contained in the gas stream are absorbed into the hydrocarbon liquid, leaving a lighter gas stream depleted in C3+ hydrocarbons compared with the gas stream;
- (b) passing the lighter gas stream as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C3+ hydrocarbons over hydrogen;
- (c) withdrawing from the permeate side a permeate stream enriched in C3+ hydrocarbons compared with the feed gas;
- (d) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas;
- (e) passing the permeate stream to a further treatment step to produce at least one hydrocarbon product.
2 more elements
A process for treating a gas stream, containing hydrogen and C3+ hydrocarbons from a catalytic cracking plant, comprising the steps of:
- (a) contacting the gas stream with a hydrocarbon liquid such that C3+ hydrocarbons contained in the gas stream are absorbed into the hydrocarbon liquid, leaving a lighter gas stream depleted in C3+ hydrocarbons compared with the gas stream;
- (b) compressing and then cooling at least a part of the lighter gas stream;
- (c) separating the compressed, cooled lighter gas stream into a recovered liquid stream and an uncondensed stream;
- (d) passing the uncondensed stream as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C3+ hydrocarbons over hydrogen;
- (e) withdrawing from the permeate side a permeate stream enriched in C3+ hydrocarbons compared with the feed gas;
- (f) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas;
- (g) passing the permeate stream to a further treatment step to produce at least one hydrocarbon product.
4 more elements
A catalytic cracking process, comprising the following steps:
- (a) cracking a hydrocarbon feedstock;
- (b) fractionating the hydrocarbon product of step (a) to produce at least one liquid stream and an overhead vapor stream;
- (c) cooling at least a part of the overhead vapor stream, thereby producing an overhead liquid stream and a wet gas stream;
- (d) compressing at least a part of the wet gas stream;
- (e) separating the compressed wet gas stream into a hydrocarbon liquid portion and a vapor portion;
- (f) passing at least a part of the vapor portion as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C2+ hydrocarbons over hydrogen;
- (g) withdrawing from the permeate side a permeate stream enriched in C2+ hydrocarbons compared with the feed gas;
- (h) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas;
- (i) passing the permeate stream to a further treatment step to produce at least one hydrocarbon product.
6 more elements
A process for treating an overhead gas stream, containing hydrogen and C2+ hydrocarbons, from an absorption column of a catalytic cracking plant, comprising the steps of:
- (a) withdrawing the gas stream from the column;
- (b) passing the gas stream as a feed gas across the feed side of a polymeric membrane having a feed side and a permeate side and being selectively permeable to C2+ hydrocarbons over hydrogen;
- (c) withdrawing from the permeate side a permeate stream enriched in C2+ hydrocarbons compared with the feed gas;
- (d) withdrawing from the feed side a residue stream enriched in hydrogen compared with the feed gas;
- (e) passing the permeate stream to a further treatment step to produce at least one hydrocarbon product, wherein the further treatment step is selected from the group consisting of condensation, distillation, and olefin/paraffin splitting.
2 more elements
Dependencies are inferred from the claim text.