US5332424A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydrocarbon fractionation by adsorbent membranes
Assignee: NATIONAL INSTITUTE FOR STRATEGIC TECHNOLOGY ACQUISITION AND COMMERCIALIZATION
•
Filing: 1993-07-28
•
Granted: 1994-07-26
•
Expires: 2013-07-28
Abstract
Abstract A method is disclosed for separating a multicomponent gas mixture comprising at least three components into three product streams by use of adsorbent membrane zones operating in series. Each product is enriched in a different component based upon the relative strength of adsorption of each component on the adsorbent material. A non-permeate primary component product is obtained by the selective adsorption and permeation through the adsorbent membranes of secondary components which are more strongly adsorbed than the primary components in the gas mixture. Two or more permeate streams enriched in the more strongly adsorbed components are withdrawn from the membrane zones as individual secondary products, each of which contains a different component distribution determined by the relative strength of adsorption of the secondary components on the adsorbent material. Increased recovery and product purity are realized by the integration of pressure swing adsorption (PSA) and cryogenic separation systems with the adsorbent membrane zones. PSA reject gas is used as a membrane sweep gas to increase the permeation rates of secondary components.
Inventors
- 👤 Madhukar B. Rao
- 👤 Shivaji Sircar
- 👤 Joseph M. Abrardo
- 👤 William F. Baade
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:20
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/22; B01D53/229; B01D53/225; B01D53/226
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
305 words
A method for separating a gas mixture containing one or more primary components and two or more secondary components, wherein said secondary components are more strongly adsorbed on an adsorbent material than said primary components, and wherein the relative adsorptive characteristics of said secondary components on said adsorbent material range from most strongly adsorbed secondary components to least strongly adsorbed secondary components, said method comprising: (a) passing a feed stream comprising said gas mixture successively through two or more membrane zones in series, each membrane zone having a permeable adsorbent membrane comprising said adsorbent material which divides the zone into a feed side and a permeate side, wherein said feed stream passes successively in series through the feed side of each membrane zone such that the nonpermeate gas from a given membrane zone provides the feed to the succeeding membrane zone, wherein said feed stream is depleted of the most strongly adsorbed secondary components in the first of said membrane zones and the least strongly adsorbed secondary components in the last of said membrane zones, and withdrawing from the feed side of the last of said membrane zones a final membrane product stream substantially depleted of said secondary components; and (b) withdrawing from the permeate side of each successive membrane zone a secondary component permeate stream, wherein the permeate stream from the first of said membrane zones is enriched in the most strongly adsorbed secondary components and the permeate stream from the last of said membrane zones is enriched in the least strongly adsorbed secondary components; wherein portions of said secondary components are adsorbed from said feed stream in said successive membrane zones by said adsorbent membranes, diffuse through the membranes as an adsorbed fluid phase, and are withdrawn from the permeate sides of said successive membrane zones to yield said secondary component permeate streams.
Claim 2
Independent Claim
305 words
A method for separating a gas mixture containing one or more primary components and two or more secondary components, wherein said secondary components are more strongly adsorbed on an adsorbent material than said primary components, and wherein the relative adsorptive characteristics of said secondary components on said adsorbent material range from most strongly adsorbed secondary components to least strongly adsorbed secondary components, said method comprising: (a) passing a feed stream comprising said gas mixture successively through two or more membrane zones in series, each membrane zone having a permeable adsorbent membrane comprising said adsorbent material which divides the zone into a feed side and a permeate side, wherein said feed stream passes successively in series through the feed side of each membrane zone such that the nonpermeate gas from a given membrane zone provides the feed to the succeeding membrane zone, wherein said feed stream is depleted of the most strongly adsorbed secondary components in the first of said membrane zones and the least strongly adsorbed secondary components in the last of said membrane zones, and withdrawing from the feed side of the last of said membrane zones a final membrane product stream substantially depleted of said secondary components; and (b) withdrawing from the permeate side of each successive membrane zone a secondary component permeate stream, wherein the permeate stream from the first of said membrane zones is enriched in the most strongly adsorbed secondary components and the permeate stream from the last of said membrane zones is enriched in the least strongly adsorbed secondary components; wherein portions of said secondary components are adsorbed from said feed stream in said successive membrane zones by said adsorbent membranes, diffuse through the membranes as an adsorbed fluid phase, and are withdrawn from the permeate sides of said successive membrane zones to yield said secondary component permeate streams.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein said one or more primary components comprise hydrogen, helium, or methane.
Claim 4
Dependent Claim
35 words
The method of claim 2 wherein said two or more secondary components are selected from the group consisting of hydrocarbons having up to five carbon atoms, carbon monoxide, carbon dioxide, and nitrogen, and hydrogen sulfide.
Claim 5
Dependent Claim
25 words
The method of claim 1 wherein said adsorbent material is selected from the group consisting of activated carbon, zeolite, activated alumina, silica, and combinations thereof.
Claim 6
Dependent Claim
22 words
The method of claim 1 wherein the pressure in said feed side of each membrane zone is between 20 and 1,200 psig.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein the pressure in said permeate side of each membrane zone is between 2 and 900 psig.
Claim 8
Dependent Claim
23 words
The method of claim 6 wherein the ratios of feed side pressure to permeate side pressure in said membrane zones are substantially equivalent.
Claim 9
Dependent Claim
36 words
The method of claim 1 which further comprises passing said final membrane product stream into a pressure swing adsorption system and withdrawing therefrom a high purity primary component product and a reject stream comprising secondary components.
Claim 10
Dependent Claim
70 words
The method of claim 8 which further comprises passing at least a portion of said reject stream through the permeate side of one of said membrane zones as a sweep gas, and withdrawing therefrom a membrane zone reject stream comprising said sweep gas and an enhanced permeate stream comprising secondary components, whereby the use of said sweep gas increases the diffusion rate of secondary components through said permeable adsorbent membrane.
Claim 11
Dependent Claim
60 words
The method of claim 9 which further comprises passing said membrane zone reject stream to a rectification system and withdrawing therefrom a secondary component product stream enriched in the least volatile of the secondary components in said membrane zone reject stream and an overhead stream enriched in the most volatile of the secondary components in said membrane zone reject stream.
Claim 12
Dependent Claim
16 words
The method of claim 10 wherein said rectification system is a dephlegmator or cryogenic distillation column.
Claim 13
Dependent Claim
25 words
The method of claim 10 which further comprises combining said overhead stream with said final membrane product stream prior to said pressure swing adsorption system.
Claim 14
Dependent Claim
69 words
The method of claim 9 which further comprises passing another portion of said reject stream through the permeate side of another of said membrane zones as a sweep gas, and withdrawing therefrom an additional membrane zone reject stream comprising said sweep gas and another enhanced permeate stream comprising secondary components, whereby the use of said sweep gas increases the diffusion rate of secondary components through said permeable adsorbent membrane.
Claim 15
Dependent Claim
66 words
The method of claim 13 which further comprises passing said additional membrane zone reject stream to an additional rectification system and withdrawing therefrom an additional secondary component product stream enriched in the least volatile of the secondary components in said additional membrane zone reject stream and an additional overhead stream enriched in the most volatile of the secondary components in said additional membrane zone reject stream.
Claim 16
Dependent Claim
26 words
The method of claim 14 which further comprises combining said additional overhead stream with said final membrane product stream prior to said pressure swing adsorption system.
Claim 17
Dependent Claim
17 words
The method of claim 14 wherein said rectification system is a dephlegmator or a cryogenic distillation column.
Claim 18
Dependent Claim
26 words
The method of claim 8 wherein said final membrane product stream is compressed to between 100 and 1200 psig prior to said pressure swing adsorption system.
References Cited (Backward Citations)
US2617493A
Cited
US2540151A
Cited
US4104037A
Cited
US3713271A
Cited
US4077779A
Cited
US4180388A
Cited
JPS58120502A
Cited
US4398926A
Cited
DE3315930A1
Cited
US5127925A
Cited
US4435191A
Cited
US4547205A
Cited
US4654063A
Cited
US4717407A
Cited
US4623704A
Cited
JPS62153389A
Cited
JPS62153390A
Cited
US4689062A
Cited
US4687498A
Cited
US4690695A
Cited
US4842718A
Cited
US4701187A
Cited
US4857078A
Cited
US4836833A
Cited
US5104425A
Cited
US5012037A
Cited
US5133785A
Cited
US5185014A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-07-25 | 1998-01-24 | 1998-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-07-25 | 2002-01-24 | 2002-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-07-25 | 2006-01-24 | 2006-07-26 | $7700.00 | Window Closed / Lapsed |