Spiral wound gas separation membrane modules
A gas separation module comprising gas separation elements, said elements comprising at least two membrane sheets and a permeate carrier sandwiched between the membrane sheets, wherein the permeate carrier comprises at least two macroporous layers and a gas-impermeable sheet located between the macroporous layers.
1. A gas separation module comprising gas separation elements, said elements comprising at least two membrane sheets and a permeate carrier sandwiched between the membrane sheets, wherein the permeate carrier comprises (i) one macroporous sheet folded around a gas-impermeable sheet; or (ii) at least two macroporous sheets and a gas-impermeable sheet located between the macroporous sheets,
wherein the gas-impermeable sheet is coextensive with the at least two macroporous sheets, and
wherein:
(a) the membrane sheets are composite membranes comprising a porous support and a discriminating layer; and
(b) the discriminating layer can discriminate between gases.
2. The gas separation module according to claim 1 wherein at least one of the gas separation elements reduces in thickness by <25% when it is subjected to a pressure of 7 million Pascal for 5 hours.
3. The gas separation module according to claim 1 being a spiral wound gas separation module.
4. The gas separation module according to claim 1 wherein the membrane sheets and/or the permeate carrier have a surface profile comprising surface projections.
5. The gas separation module according to claim 4 wherein the surface projections comprise ribs and/or grooves.
6. The gas separation module according to claim 1 wherein the macroporous sheets comprise a knitted fabric.
7. The gas separation module according to claim 1 wherein the gas-impermeable sheet has a thickness of less than 0.1 cm.
8. The gas separation module according to claim 1 which further comprises a central tube and wherein the gas separation elements are fixed to the central tube such that gas which permeates through the membrane can flow through the permeate carrier and into the central tube but gas which does not permeate through the membrane cannot enter the central tube.
9. The gas separation module according to claim 1 which comprises two or more of the said gas separation elements and a feed spacer located between the gas separation elements.
10. The gas separation module according to claim 1 wherein the contact area of the membrane sheets with the permeate carrier is <50%, and wherein the contact area of the membrane sheets with the permeate carrier is as determined by forming a membrane sheet—permeate carrier laminate using a laminator, peeling off the membrane sheets and determining the contact area by performing measurements using a microscope.
11. A process for separating gases and/or purifying a feed gas comprising at least two different gaseous components comprising passing the feed gas through a module according to claim 1 such that feed gas is separated into a permeate gas and a retentate gas, one of which is enriched in at least one of the said gaseous components and one of which is depleted in at least one of the said gaseous components.
12. The gas separation module according to claim 1 wherein (i) the membrane sheets and/or the permeate carrier have a surface profile comprising surface projections wherein the surface projections comprise ribs and/or grooves; and (ii) the permeate carrier comprises two or more macroporous sheets and a gas-impermeable sheet located between the macroporous sheets.
13. The gas separation module according to claim 1 wherein (i) the membrane sheets and/or the permeate carrier have a surface profile comprising surface projections wherein the surface projections comprise ribs and/or grooves; and (ii) the permeate carrier comprises one macroporous sheet folded around a gas-impermeable sheet.
14. The gas separation module according to claim 1 wherein (i) the membrane sheets and/or the permeate carrier have a surface profile comprising surface projections wherein the surface projections comprise ribs and/or grooves; (ii) the permeate carrier comprises one macroporous sheet folded around a gas-impermeable sheet; and (iii) the contact area of the membrane sheets with the permeate carrier is <50%, and wherein the contact area of the membrane sheets with the permeate carrier is as determined by forming a membrane sheet—permeate carrier laminate using a laminator, peeling off the membrane sheets and determining the contact area by performing measurements using a microscope.
15. The gas separation module according to claim 13 being a spiral wound gas separation module.
16. The gas separation module according to claim 14 being a spiral wound gas separation module.
17. The gas separation module according to claim 14 being a spiral wound gas separation module wherein at least one of the gas separation elements reduces in thickness by <25% when it is subjected to a pressure of 7 million Pascal for 5 hours.
18. A process for separating gases and/or purifying a feed gas comprising at least two different gaseous components comprising passing the feed gas through a gas separation module according to claim 14 such that feed gas is separated into a permeate gas and a retentate gas, one of which is enriched in at least one of the said gaseous components and one of which is depleted in at least one of the said gaseous components.