Title: Methane/nitrogen separation process

Abstract

A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

Inventors:

Baker, Richard W ^[1]; Lokhandwala, Kaaeid A ^[2]; Pinnau, Ingo ^[1]; Segelke, Scott ^[3]

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+ Show Inventor Affiliations

1. Palo Alto, CA
2. Menlo Park, CA
3. Mountain View, CA

Issue Date:

1997-01-01

Research Org.:

Membrane Technology and Research, Inc. (Menlo Park, CA)

OSTI Identifier:

871151

Patent Number(s):

5669958

Assignee:

Membrane Technology and Research, Inc. (Menlo Park, CA)

Patent Classifications (CPCs):

B - PERFORMING OPERATIONS B01 - PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL B01D - SEPARATION

F - MECHANICAL ENGINEERING F25 - REFRIGERATION OR COOLING F25J - LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE

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B - PERFORMING OPERATIONS B01 - PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL B01D - SEPARATION

B01D53/002 - {by condensation}
B01D53/22 - by diffusion
B01D53/226 - {in serial connexion}
B01D53/228 - {characterised by specific membranes}
B01D53/229 - {Integrated processes
B01D69/02 - characterised by their properties
B01D71/24 - Rubbers
B01D71/44 - Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups B01D71/26 - B01D71/42
B01D71/70 - Polymers having silicon in the main chain, with or without sulfur, nitrogen, oxygen or carbon only

F - MECHANICAL ENGINEERING F25 - REFRIGERATION OR COOLING F25J - LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS {OR LIQUEFIED GASEOUS} MIXTURES BY PRESSURE AND COLD TREATMENT {OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE

F25J2205/40 - using hybrid system, i.e. combining cryogenic and non-cryogenic separation techniques
F25J2205/80 - using membrane, i.e. including a permeation step
F25J2240/12 - the fluid being nitrogen
F25J2270/04 - Internal refrigeration with work-producing gas expansion loop
F25J3/0209 - {Natural gas or substitute natural gas}
F25J3/0233 - {separation of CnHm with 1 carbon atom or more}
F25J3/0242 - {separation of CnHm with 3 carbon atoms or more}
F25J3/0257 - {separation of nitrogen
F25J3/061 - {Natural gas or substitute natural gas}
F25J3/0635 - {separation of CnHm with 1 carbon atom or more}
F25J3/0645 - {separation of CnHm with 3 carbon atoms or more}

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DOE Contract Number:  

FG03-94ER81809

Resource Type:

Patent

Country of Publication:

United States

Language:

English

Subject:

methane; nitrogen; separation; process; membrane; treating; gas; stream; containing; example; natural; preferentially; permeating; rejecting; found; meet; pipeline; specifications; acceptably; loss; exhibit; selectivity; achieved; rubbery; super-glassy; membranes; temperatures; separating; ethylene; natural gas; separation process; gas stream; stream containing; membrane separation; nitrogen separation; containing methane; gas pipe; rejecting nitrogen; permeating methane; nitrogen selectivity; preferentially permeating; /95/62/