Control process and apparatus for membrane separation systems

Claim 2

In a permeable membrane gas separation process which comprises: (a) passing a gaseous feed stream comprising a component to a permeable membrane gas separation system at a substantially constant flow rate and elevated feed pressure, said feed pressure being equal to or higher than the pressure required to operate the permeable membrane gas separation system and said feed stream being subject to fluctuations in composition; and (b) recovering from said permeable membrane gas separation system, an effluent stream comprising a permeate stream or a non-permeate stream; the improvement which comprises controlling the concentration of said component in said effluent stream by; 1) sensing a change in a characteristic of said effluent stream that is indicative of a change in the concentration of said component in said feed stream of from about 1 to 30%; and 2) without substantially altering the feed pressure or flow rate, performing a pressure adjustment on said permeate stream or said non-permeate stream in response to said sensed characteristic to alter the concentration of said component in said effluent stream as necessary to obtain a predetermined concentration of said component in said effluent stream.

Claim 3

A process according to claim 1 wherein said sensed characteristic is the concentration of said component in said effluent stream.

Claim 4

A process according to claim 1 wherein said effluent stream comprises said permeate stream.

Claim 5

A process according to claim 3 wherein said pressure adjustment is performed on said non-permeate stream.

Claim 6

A process according to claim 1 wherein said effluent stream comprises said non-permeate stream.

Claim 7

A process according to claim 5 wherein said pressure adjustment is performed on said permeate stream.

Claim 8

A process according to claim 1 including the further steps of: sensing the concentration of said component in said effluent stream; comparing the sensed concentration to a reference value; and establishing a target value of said effluent stream in response to the comparison of the sensed concentration and the reference value.

Claim 9

A process for controlling the concentration of a component in a permeate effluent stream from a permeable membrane gas separation system, which comprises: (a) passing a gaseous feed stream comprising said component and at least one other component to the permeable membrane gas separation system at a substantially constant flow rate and feed pressure of at least about 100 psia, said feed pressure being equal to or greater than the pressure required to operate the permeable membrane gas separation system and said feed stream being subject to fluctuations in composition; (b) recovering a non-permeate effluent stream enriched in the at least one other component relative to said feed stream; (c) recovering a permeate effluent stream enriched in said component relative to said feed stream; (d) sensing a change in the concentration of said component in said permeate effluent stream that is indicative of a change in the concentration of said component in said feed stream of from about 1 to 30%; and (e) without substantially altering the feed pressure or flow rate, performing a pressure adjustment on said nonpermeate eflfuent stream in response to said sensed concentration to alter the concentration of said component in said permeate effluent stream as necessary to obtain a predetermined concentration of said component in said permeate stream without substantially altering the pressure of said permeate stream.

Claim 10

A process for controlling the concentration of a component in a permeate effluent stream from a permeable membrane gas separation system, which comprises: (a) passing a gaseous feed stream comprising said component and at least one other component to the permeable membrane gas separation system at a substantially constant flow rate and feed pressure of at least about 100 psia, said feed pressure being equal to or greater than the pressure required to operate the permeable membrane gas separation system and said feed stream being subject to fluctuations in composition; (b) recovering a non-permeate effluent stream enriched in the at least one other component relative to said feed stream; (c) recovering a permeate effluent stream enriched in said component relative to said feed stream; (d) sensing a change in the concentration of said component in said permeate effluent stream that is indicative of a change in the concentration of said component in said feed stream of from about 1 to 30%; and (e) without substantially altering the feed pressure or flow rate, performing a pressure adjustment on said nonpermeate eflfuent stream in response to said sensed concentration to alter the concentration of said component in said permeate effluent stream as necessary to obtain a predetermined concentration of said component in said permeate stream without substantially altering the pressure of said permeate stream.

Claim 11

A process according to claim 8 wherein said feed pressure is in the range of from about 500 to about 2000 psia.

Claim 12

A process according to claim 8 wherein said component is hydrogen.

Claim 13

A process according to claim 10 wherein the at least one other component comprises hydrocarbons in the C1 to C5 carbon range.

Claim 14

A process for controlling the concentration of a component in a non-permeate effluent stream from a permeable membrane gas separation system, which comprises: (a) passing a gaseous feed stream comprising said component and at least one other component to the permeable membrane gas separation system at a substantially constant flow rate and feed pressure of at least about 100 psia, said feed pressure being equal to or greater than the pressure required to operate the permeable membrane gas separation system and said feed stream being subject to fluctuations in composition; (b) recovering a non-permeate effluent stream enriched in said component relative to said feed stream; (c) recovering a permeate effluent stream enriched in the at least one other component relative to said feed stream; (d) sensing a change in the concentration of said component in said non-permeate effluent stream that is indicative of a change in the concentration of said component in said feed stream of from about 1 to 30%; and (e) without substantially altering the feed pressure or flow rate, performing a pressure adjustment on said permeate effuent stream in response to said sensed concentration to alter the concentration of said component in said non-permeate effluent stream as necessary to obtain a predetermined concentration of said component in said non-permeate stream without substantially altering the pressure of said non-permeate stream.

Claim 15

A process for controlling the concentration of a component in a non-permeate effluent stream from a permeable membrane gas separation system, which comprises: (a) passing a gaseous feed stream comprising said component and at least one other component to the permeable membrane gas separation system at a substantially constant flow rate and feed pressure of at least about 100 psia, said feed pressure being equal to or greater than the pressure required to operate the permeable membrane gas separation system and said feed stream being subject to fluctuations in composition; (b) recovering a non-permeate effluent stream enriched in said component relative to said feed stream; (c) recovering a permeate effluent stream enriched in the at least one other component relative to said feed stream; (d) sensing a change in the concentration of said component in said non-permeate effluent stream that is indicative of a change in the concentration of said component in said feed stream of from about 1 to 30%; and (e) without substantially altering the feed pressure or flow rate, performing a pressure adjustment on said permeate effuent stream in response to said sensed concentration to alter the concentration of said component in said non-permeate effluent stream as necessary to obtain a predetermined concentration of said component in said non-permeate stream without substantially altering the pressure of said non-permeate stream.

Claim 16

A process according to claim 12 wherein said component comprises natural gas hydrocarbons.

Claim 17

A process according to claim 13 wherein the at least one other component is carbon dioxide.

Claim 18

A process according to claim 12 wherein said component comprises a mixture of hydrogen and carbon monoxide in a molar ratio of from about 1 to 4 moles of hydrogen per mole of carbon monoxide.

Claim 19

A process according to claim 15 wherein the at least one other component is carbon dioxide.