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A gas separation process for treating off-gas streams from reaction processes, and reaction processes including such gas separation. The invention involves flowing the off-gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, and passing the perme

A gas separation process for treating off-gas streams from reaction processes, and reaction processes including such gas separation. The invention involves flowing the off-gas across the feed side of a membrane, flowing a sweep gas stream, usually air, across the permeate side, and passing the permeate/sweep gas mixture to the reaction. The process recovers unreacted feedstock that would otherwise be lost in the waste gases in an energy efficient manner.

대표청구항 ▼

1. A reaction process, comprising: (a) providing a reaction zone;(b) introducing a first reaction stream comprising a reagent A and a second reaction stream comprising a reagent B into the reaction zone;(c) reacting reagents A and B, thereby forming a reaction product in a reaction mixture;(d) withd

1. A reaction process, comprising: (a) providing a reaction zone;(b) introducing a first reaction stream comprising a reagent A and a second reaction stream comprising a reagent B into the reaction zone;(c) reacting reagents A and B, thereby forming a reaction product in a reaction mixture;(d) withdrawing at least a portion of the reaction mixture from the reaction zone;(e) removing at least a portion of the reaction product from the withdrawn portion of the reaction mixture to form a reaction product stream and a non-product stream containing unreacted reagent A and at least one inert component C;(f) providing a membrane having a feed side and a permeate side, and being selectively permeable to reagent A over component C;(g) passing at least a portion of the non-product stream across the feed side;(h) passing a stream containing reagent B as a sweep stream across the permeate side;(i) withdrawing from the feed side a vent stream depleted in reagent A compared with the non-product stream;(j) withdrawing from the permeate side a permeate stream comprising reagent A and reagent B;(k) recirculating at least a portion of the permeate stream to the reaction zone as at least part of the second reaction stream. 2. The process of claim 1, wherein the reaction process is an oxidation process. 3. The process of claim 1, wherein reagent A is chosen from the group consisting of methanol, ethylene, propylene, butylenes, isoprene, ethane, n-butane, iso-butane, benzene, toluene, cyclohexane, cumene, o-xylene and p-xylene. 4. The process of claim 1, wherein component C is nitrogen. 5. The process of claim 1, wherein the sweep stream follows a sweep flow direction across the permeate side, the non-product stream follows a feed flow direction across the feed side, and the sweep flow direction is substantially countercurrent to the feed flow direction. 6. The process of claim 1, wherein the first reaction stream and the second reaction stream are combined before they are introduced into the reaction zone. 7. The process of claim 1, wherein the membrane exhibits a permeance A of at least 100 gpu for reagent A and a selectivity in favor of reagent A over component C of at least 10 under process operating conditions. 8. The process of claim 1, wherein the membrane exhibits a permeance A for reagent A and a permeance B for reagent B and permeance B is less than 20% of permeance A. 9. The process of claim 1, wherein a first total pressure is maintained on the feed side, a second total pressure is maintained on the permeate side and the first total pressure is greater than the second total pressure. 10. The process of claim 9, wherein the second total pressure is at least atmospheric pressure. 11. An oxidation process, comprising: (a) performing a reaction step in a reaction zone, by reacting an organic feedstock chosen from the group consisting of methanol, ethylene, propylene, butylenes, isoprene, ethane, n-butane, iso-butane, benzene, toluene, cyclohexane, cumene, o-xylene and p-xylene, with oxygen, thereby forming an organic product;(b) withdrawing from the reaction zone a crude organic product stream comprising the organic product, the organic feedstock, and an inert gas;(c) removing at least a portion of the organic product from the crude organic product stream to form a non-product stream;(d) providing a membrane having a feed side and a permeate side, and being selectively permeable to the organic feedstock over nitrogen;(e) passing at least a portion of the non-product stream across the feed side;(f) passing air, oxygen-enriched air or oxygen as a sweep stream across the permeate side;(g) withdrawing from the feed side an organic-feedstock depleted vent stream;(h) withdrawing from the permeate side a permeate stream comprising oxygen and the organic feedstock;(i) recirculating at least a portion of the permeate stream to the reaction zone. 12. The process of claim 11, wherein the organic feedstock is selected from the group consisting of propylene and n-butane. 13. The process of claim 11, wherein the organic product is chosen from the group consisting of alcohols, aldehydes, ketones, acids, and esters. 14. The process of claim 11, wherein the organic product is chosen from the group consisting of maleic anhydride, acetic acid, acrylonitrile, acrylic acid and formic acid. 15. The process of claim 11, wherein the inert gas is nitrogen and the membrane exhibits a nitrogen permeance of at least 100 gpu under process operating conditions. 16. The process of claim 11, wherein the membrane exhibits a selectivity in favor of the organic feedstock over nitrogen of at least 10 under process operating conditions. 17. The process of claim 11, wherein the membrane exhibits a permeance A for the organic feedstock and a permeance B for oxygen and permeance B is less than 20% of permeance A. 18. The process of claim 11, wherein a first total pressure is maintained on the feed side, a second total pressure is maintained on the permeate side and the first total pressure is greater than the second total pressure. 19. The process of claim 18, wherein the second total pressure is at least atmospheric pressure. 20. The process of claim 11, wherein the sweep stream follows a sweep flow direction across the permeate side, the non-product stream follows a feed flow direction across the feed side, and the sweep flow direction is substantially countercurrent to the feed flow direction.