US 2002/0152889 A1 · Gas separation using organic-vapor-resistant membranes in conjunction with organic-vapor-selective membranes · patentgrep

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Abstract

A process for treating a gas mixture containing at least an organic compound gas or vapor and a second gas, such as natural gas, refinery off-gas or air. The process uses two sequential membrane separation steps, one using membrane selective for the organic compound over the second gas, the other selective for the second gas over the organic vapor. The second-gas-selective membranes use a selective layer made from a polymer having repeating units of a fluorinated polymer, and demonstrate good resistance to plasticization by the organic components in the gas mixture under treatment, and good recovery after exposure to liquid aromatic hydrocarbons. The membrane steps can be combined in either order.

Claims66

Dependent claims

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the gaseous hydrocarbon over the second gas;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer comprising repeating units having a fluorinated cyclic structure of an at least 5-member ring, the polymer having a fractional free volume no greater than about 0.3;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first feed side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the gaseous hydrocarbon compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the gaseous hydrocarbon compared with the gas mixture;
(g) passing the first residue stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the second gas compared with the first residue stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the second gas compared with the first residue stream.

8 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the gaseous hydrocarbon over the second gas;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer having:
(i) a ratio of fluorine to carbon atoms in the polymer greater than 1:1;
(ii) a fractional free volume no greater than about 0.3;
and
(iii) a glass transition temperature of at least about 100° C.;
and the second membrane being characterized by a post-exposure selectivity for the second gas over the gaseous hydrocarbon, after exposure of the separation membrane to liquid toluene and subsequent drying, that is at least about 65% of a pre-exposure selectivity for the second gas over the gaseous hydrocarbon, as measured pre- and post-exposure with a test gas mixture of the same composition and under like conditions;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first feed side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the gaseous hydrocarbon compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the gaseous hydrocarbon compared with the gas mixture;
(g) passing the first residue stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the second gas compared with the first residue stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the second gas compared with the first residue stream.

13 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer comprising repeating units having a fluorinated cyclic structure of an at least 5-member ring, the polymer having a fractional free volume no greater than about 0.3;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the gaseous hydrocarbon over the second gas;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first feed side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the second gas compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the second gas compared with the gas mixture;
(g) passing the first residue stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the gaseous hydrocarbon compared with the first residue stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the gaseous hydrocarbon compared with the first residue stream.

8 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer having:
(i) a ratio of fluorine to carbon atoms in the polymer greater than 1:1;
(ii) a fractional free volume no greater than about 0.3;
and
(iii) a glass transition temperature of at least about 100° C.;
and the first membrane being characterized by a post-exposure selectivity for the second gas over the gaseous hydrocarbon, after exposure of the separation membrane to liquid toluene and subsequent drying, that is at least about 65% of a pre-exposure selectivity for the second gas over the gaseous hydrocarbon, as measured pre- and post-exposure with a test gas mixture of the same composition and under like conditions;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the gaseous hydrocarbon over the second gas;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first feed side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the second gas compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the second gas compared with the gas mixture;
(g) passing the first residue stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the gaseous hydrocarbon compared with the first residue stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the gaseous hydrocarbon compared with the first residue stream.

13 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the gaseous hydrocarbon over the second gas;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer comprising repeating units having a fluorinated cyclic structure of an at least 5-member ring, the polymer having a fractional free volume no greater than about 0.3;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first permeate side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the gaseous hydrocarbon compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the gaseous hydrocarbon compared with the gas mixture;
(g) passing the first permeate stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the second gas compared with the first permeate stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the second gas compared with the first permeate stream.

8 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the gaseous hydrocarbon over the second gas;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer having:
(i) a ratio of fluorine to carbon atoms in the polymer greater than 1:1;
(ii) a fractional free volume no greater than about 0.3;
and
(iii) a glass transition temperature of at least about 1 00° C.;
and the second membrane being characterized by a post-exposure selectivity for the second gas over the gaseous hydrocarbon, after exposure of the separation membrane to liquid toluene and subsequent drying, that is at least about 65% of a pre-exposure selectivity for the second gas over the gaseous hydrocarbon, as measured pre- and post-exposure with a test gas mixture of the same composition and under like conditions;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first permeate side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the gaseous hydrocarbon compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the gaseous hydrocarbon compared with the gas mixture;
(g) passing the first permeate stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the second gas compared with the first permeate stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the second gas compared with the first permeate stream.

13 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the selond gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer comprising repeating units having a fluorinated cyclic structure of an at least 5-member ring, the polymer having a fractional free volume no greater than about 0.3;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the gaseous hydrocarbon over the second gas;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first permeate side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the second gas compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the second gas compared with the gas mixture;
(g) passing the first permeate stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the gaseous hydrocarbon compared with the first permeate stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the gaseous hydrocarbon compared with the first permeate stream.

8 more elements

A process for treating a gas mixture comprising a gaseous hydrocarbon and a second gas, the process comprising:

(a) providing a first membrane unit containing a first membrane having a first feed side and a first permeate side, the first membrane being selective in favor of the second gas over the gaseous hydrocarbon, and including a selective layer comprising a polymer having:
(i) a ratio of fluorine to carbon atoms in the polymer greater than 1:1;
(ii) a fractional free volume no greater than about 0.3;
and
(iii) a glass transition temperature of at least about 100° C.;
and the first membrane being characterized by a post-exposure selectivity for the second gas over the gaseous hydrocarbon, after exposure of the separation membrane to liquid toluene and subsequent drying, that is at least about 65% of a pre-exposure selectivity for the second gas over the gaseous hydrocarbon, as measured pre- and post-exposure with a test gas mixture of the same composition and under like conditions;
(b) providing a second membrane unit containing a second membrane having a second feed side and a second permeate side, the second membrane being selective in favor of the gaseous hydrocarbon over the second gas;
the second membrane unit being connected in series with the first membrane unit such that gas leaving the first permeate side can enter the second membrane unit on the second feed side;
(c) passing the gas mixture into the first membrane unit and across the first feed side;
(d) providing a first driving force for transmembrane permeation;
(e) withdrawing from the first feed side a first residue stream depleted in the second gas compared with the gas mixture;
(f) withdrawing from the first permeate side a first permeate stream enriched in the second gas compared with the gas mixture;
(g) passing the first permeate stream into the second membrane unit and across the second feed side;
(h) providing a second driving force for transmembrane permeation;
(i) withdrawing from the second feed side a second residue stream depleted in the gaseous hydrocarbon compared with the first permeate stream;
(j) withdrawing from the second permeate side a second permeate stream enriched in the gaseous hydrocarbon compared with the first permeate stream.

13 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/105,861Filed 25 Mar 2002
Priority: 19 May 2000
Published: 24 Oct 2002
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

B01D 53/228
By diffusion: characterised by specific membranes
B01D 69/02
Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes…:…
B01D 71/32
Polyalkenyl halides: containing fluorine atoms
B01D 71/44
Organic material: polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, not provided for in a single one of groups…

Family

Application09/574,420Continuation in part · filed 19 May 2000
Application09/574,303Continuation in part · filed 19 May 2000
Application10/105,861Continuation in part · filed 25 Mar 2002
US 6,361,582 B1Related patent
US 6,361,583 B1Related patent
US 6,572,679 B2Related patent
US 2002/0152889 A1This patent

From the US filing history. Foreign family members aren’t listed.

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