Recovery of gases, especially permanent gases, from streams of matter, especially from offgas streams from polymerizations

• US 10,092,876 B2
• Filed: 07/23/2015
• Issued: 10/09/2018
• Est. Priority Date: 08/07/2014
• Status: Active Grant

• Current Assignee: Linde AG (Linde Plc)
• Original Assignee: Linde AG (Linde Plc)
• Inventors: Witzleb, Volker, Leitmayr, Werner, Voss, Christian, Tota, Akos, Bauer, Martin
• Primary Examiner(s): Shumate, Anthony R
• Application Number:
  US15/500,593
• Publication Number:
  US 20170209830A1
• Time in Patent Office: 1,174 Days
• CPC Class Codes: B01D 2256/24 Hydrocarbons
• CPC Class Codes: B01D 2257/102 Nitrogen
• CPC Class Codes: B01D 2257/108 Hydrogen
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01D 53/229 Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
• CPC Class Codes: C07C 11/04 Ethylene
• CPC Class Codes: C07C 11/06 Propene
• CPC Class Codes: C07C 7/005 Processes comprising at least two steps in series
• CPC Class Codes: C07C 7/12 by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
• CPC Class Codes: C07C 7/144 using membranes, e.g. selective permeation
• CPC Class Codes: H05K 999/99 dummy group

Abstract

A method of cleaning a stream of matter that includes a C2+ fraction and a first gaseous substance and a second gaseous substance. The stream of matter is subjected to a pressure swing adsorption to remove the C2+ fraction by means of a membrane to obtain a retentate and a permeate. The first substance is enriched in retentate and depleted in permeate and the second substance is depleted in retentate and enriched in permeate.

Claims

1. A method of cleaning a stream of matter, wherein said stream of matter comprises a C₂₊ fraction, at least one first gaseous substance, and a different second gaseous substance, said method comprising

subjecting said stream of matter to pressure swing adsorption to remove said C₂₊ fraction, and

after removal of the C₂₊ fraction, separating said stream of matter by means of a membrane, wherein said stream of matter is separated into a retentate and a permeate,

wherein said at least one first gaseous substance is enriched in the retentate and said second gaseous substance is depleted in the retentate, and said at least one first gaseous substance is depleted in the permeate and said second gaseous substance is enriched in the permeate.

2. The method as claimed in claim 1, wherein the first and second gaseous substances are selected from hydrogen, nitrogen, methane, carbon monoxide and carbon dioxide.

3. The method as claimed in claim 1, wherein said membrane comprises at least one of the following substances:

polysulfone, polyether sulfone, polyimide, and polyamide.

4. The method as claimed in claim 1, wherein said stream of matter is an offgas stream.

5. The method as claimed in claim 1, wherein said stream of matter is obtained in a process conducted upstream of the pressure swing adsorption.

6. The method as claimed in claim 5, wherein said retentate is recycled into the process.

7. The method as claimed in claim 5, wherein said process comprises polymerization, and wherein the stream of matter is obtained as an offgas stream of the polymerization.

8. The method as claimed in claim 1, wherein said C₂₊ fraction contains ethylene or propylene.

9. The method as claimed in claim 1, wherein said first gaseous substance is nitrogen.

10. The method as claimed in claim 1, wherein said second gaseous substance is hydrogen.

11. The method as claimed in claim 1, further comprising combusting said permeate.

12. The method as claimed in claim 1, wherein said membrane is formed from at least one of the following substances:

polysulfone, polyether sulfone, polyimide, and polyamide.

13. The method as claimed in claim 5, wherein said process comprises polymerization, and wherein the stream of matter is obtained as an offgas stream of said polymerization by purging a polymer produced by said polymerization with a gas stream.

14. The method as claimed in claim 9, wherein said second gaseous substance is hydrogen.

15. The method as claimed in claim 8, wherein said first gaseous substance is nitrogen and said second gaseous substance is hydrogen.

16. The method as claimed in claim 1, wherein

said stream of matter is obtained from a polymerization process, conducted upstream of the pressure swing adsorption, wherein ethylene or propylene is used as monomer in said polymerization process,

wherein said C₂₊ fraction contains ethylene or propylene, said first gaseous substance is nitrogen, and said second gaseous substance is hydrogen, and

wherein said retentate is recycled to said polymerization process.

17. The method as claimed in claim 16, wherein said retentate is used to purging a polymer produced by said polymerization.

18. The method as claimed in claim 16, wherein said stream of matter is a purge gas or a stripping gas obtained from said process.

19. The method as claimed in claim 1, wherein said pressure swing adsorption is conducted at pressures of 5 bar to 30 bar and at a temperature of 10°

C. to 50°

C.

20. The method as claimed in claim 1, wherein said separating by said membrane is conducted at a pressure in the range from 5 bar to 30 bar and at a temperature in the range from 20°

C. to 80°

C.