Mixed gas separation method and mixed gas separation device

Patent metadata

Field	Value
Publication number	US-2023330594-A1
Application number	US-202318338448-A
Country	US
Kind code	A1
Filing date	Jun 21, 2023
Priority date	Jan 7, 2021
Publication date	Oct 19, 2023
Grant date	—

Abstract

A mixed gas separation method includes supplying a mixed gas containing at least N 2 , H 2 , and CO 2 and having a CO 2 concentration of 30% or less by volume to a first separation membrane that selectively allows passage of H 2 , supplying the first non-permeated gas to a second separation membrane that selectively allows passage of CO 2 , and supplying the second non-permeated gas to a CO 2 collector that separates and collects CO 2 by a separation method other than membrane separation to collect CO 2 contained in the second non-permeated gas. The first non-permeated gas has a CO 2 concentration that is 5% or more by volume higher than or equal to the CO 2 concentration in the mixed gas. The second non-permeated gas has an N 2 concentration of 50% or more by volume and an H 2 concentration of 30% or less by volume.

First claim

1 . A mixed gas separation method comprising:
a) supplying a mixed gas containing at least N 2 , H 2 , and CO 2 and having a CO 2 concentration of 30% or less by volume to a first separation membrane that selectively allows passage of H 2 to separate said mixed gas into a first permeated gas that has permeated through said first separation membrane and a first non-permeated gas that has not permeated through said first separation membrane; b) supplying said first non-permeated gas to a second separation membrane that selectively allows passage of CO 2 to separate said first non-permeated gas into a second permeated gas that has permeated through said second separation membrane and a second non-permeated gas that has not permeated through said second separation membrane; and c) supplying said second non-permeated gas to a CO 2 collector that separates and collects CO 2 by a separation method other than membrane separation to collect CO 2 contained in said second non-permeated gas, wherein said first non-permeated gas has a CO 2 concentration that is 5% or more by volume higher than or equal to the CO 2 concentration in said mixed gas, said second non-permeated gas has an N 2 concentration of 50% or more by volume, and said second non-permeated gas has an H 2 concentration of 30% or less by volume.

2 . The mixed gas separation method according to claim 1 , wherein
after said operation a), said first permeated gas is mixed with a gas exhausted from said CO 2 collector.

3 . The mixed gas separation method according to claim 1 , wherein
after said operation a), said first permeated gas is supplied to said CO 2 collector.

4 . The mixed gas separation method according to claim 1 , wherein
said second separation membrane has a CO 2 recovery rate of 70% or higher.

5 . The mixed gas separation method according to claim 1 , wherein
the separation method used in said CO 2 collector to separate CO 2 is chemical absorption.

6 . The mixed gas separation method according to claim 1 , wherein
said second non-permeated gas has an N 2 concentration of 60% or more by volume, and said second non-permeated gas has a CO 2 concentration of 30% or less by volume.

7 . The mixed gas separation method according to claim 1 , wherein
said second permeated gas has a CO 2 concentration of 97% or more by volume.

8 . The mixed gas separation method according to claim 1 , wherein
said mixed gas supplied to said first separation membrane in said operation a) has a pressure of 1.5 MPaG or higher.

9 . The mixed gas separation method according to claim 1 , wherein
said first separation membrane has H 2 /CO 2 selectivity of 100 or higher, and said second separation membrane has CO 2 /H 2 selectivity of 100 or higher.

10 . The mixed gas separation method according to claim 1 , wherein
at least one of said first separation membrane or said second separation membrane is a zeolite membrane.

11 . A mixed gas separation device comprising:
a first separation membrane that selectively allows passage of H 2 ; a second separation membrane that selectively allows passage of CO 2 ; a CO 2 collector that separates and collects CO 2 by a separation method other than membrane separation; a mixed-gas supplier that supplies a mixed gas containing at least N 2 , H 2 , and CO 2 and having a CO 2 concentration of 30% or less by volume to said first separation membrane; a first non-permeated gas passage that guides a first non-permeated gas that has not permeated through said first separation membrane in said mixed gas, to said second separation membrane; and a second non-permeated gas passage that guides a second non-permeated gas that has not permeated through said second separation membrane in said first non-permeated gas, to said CO 2 collector, the first non-permeated gas being supplied to said first non-permeated gas passage from said second separation membrane, wherein said CO 2 collector collects CO 2 contained in said second non-permeated gas supplied through said second non-permeated gas passage, said first non-permeated gas has a CO 2 concentration that is 5% or more by volume higher than or equal to the CO 2 concentration in said mixed gas, said second non-permeated gas has an N 2 concentration of 50% or more by volume, and said second non-permeated gas has an H 2 concentration of 30% or less by volume.

12 . The mixed gas separation device according to claim 11 , further comprising:
a first permeated gas passage that guides a first permeated gas that has permeated through said first separation membrane to cause said first permeated gas to be mixed with a gas exhausted from said CO 2 collector.

13 . The mixed gas separation device according to claim 11 , further comprising:
a first permeated gas passage that guides a first permeated gas that has permeated through said first separation membrane, to said CO 2 collector.

14 . The mixed gas separation device according to claim 11 , wherein
said second separation membrane has a CO 2 recovery rate of 70% or higher.

15 . The mixed gas separation device according to claim 11 , wherein
the separation method used in said CO 2 collector to separate CO 2 is chemical absorption.

16 . The mixed gas separation device according to claim 11 , wherein
said second non-permeated gas has an N 2 concentration of 60% or more by volume, and said second non-permeated gas has a CO 2 concentration of 30% or less by volume.

17 . The mixed gas separation device according to claim 11 , wherein
said second permeated gas that has permeated through said second separation membrane has a CO 2 concentration of 97% or more by volume.

18 . The mixed gas separation device according to claim 11 , wherein
said mixed gas supplied to said first separation membrane has a pressure of 1.5 MPaG or higher.

19 . The mixed gas separation device according to claim 11 , wherein
said first separation membrane has H 2 /CO 2 selectivity of 100 or higher, and said second separation membrane has CO 2 /H 2 selectivity of 100 or higher.

20 . The mixed gas separation device according to claim 11 , wherein
at least one of said first separation membrane or said second separation membrane is a zeolite membrane.

Assignees

• Ngk Insulators Ltd

Inventors

• Noda Kenichi

Classifications

• B01D53/228 Primary

  characterised by specific membranes · CPC title

• B01D69/142

  with "carriers" · CPC title

• B01D2257/108

  Hydrogen · CPC title

• B01D2257/102

  Nitrogen · CPC title

• B01D2257/504

  Carbon dioxide · CPC title