Process for the purification of an aqueous stream coming from the fischer-tropsch reaction

Patent metadata

Field	Value
Publication number	US-9289725-B2
Application number	US-200913062585-A
Country	US
Kind code	B2
Filing date	Aug 7, 2009
Priority date	Sep 9, 2008
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Process for the purification of an aqueous stream coming from the Fischer-Tropsch reaction which comprises: feeding said aqueous stream containing the organic by products of the reaction to one or more pervaporation units, said one or more pervaporation units comprising at least one polymeric pervaporation membrane, obtaining two outgoing streams: —an aqueous stream (i) enriched in alcohols having from 1 to 8 carbon atoms, preferably from 2 to 4 carbon atoms; —an aqueous stream (ii) enriched in water.

First claim

The invention claimed is:

1. A process for purifying a first aqueous stream coming from a Fischer-Tropsch reaction, the first aqueous stream comprising an aldehyde, a ketone, an acid, a nitrogenated compound, a sulfurated compound, and traces of metals, the process comprising:
feeding the first aqueous stream to at least one pervaporation unit, wherein the at least one pervaporation unit comprises at least one polymeric pervaporation membrane, to obtain two outgoing streams:
(i) a second aqueous stream enriched in at least one alcohol having from 1 to 8 carbon atoms, with respect to said first aqueous stream; and
(ii) a third aqueous stream enriched in water, wherein said first aqueous stream is fed to said at least one pervaporation unit without any intervening distillation.

2. The process of claim 1 , wherein the second aqueous stream (i) is enriched in at least one alcohol having from 2 to 4 carbon atoms.

3. The process of claim 1 , wherein the second aqueous stream (i) has an alcohol concentration higher than or equal to 40% by weight.

4. The process of claim 3 , wherein the second aqueous stream (i) has an alcohol concentration higher than or equal to 80% by weight.

5. The process of claim 4 , wherein the second aqueous stream (i) has an alcohol concentration higher than or equal to 95% by weight.

6. A process for purifying a first aqueous stream coming from a Fischer-Tropsch reaction, the first aqueous stream comprising an aldehyde, a ketone, an acid, a nitrogenated compound, a sulfurated compound, and traces of metals, the process comprising:
feeding the first aqueous stream to at least one pervaporation unit, wherein the at least one pervaporation unit comprises at least one polymeric pervaporation membrane, to obtain two outgoing streams:
(i) a second aqueous stream enriched in at least one alcohol having from 1 to 8 carbon atoms, with respect to said first aqueous stream; and
(ii) a third aqueous stream enriched in water,
wherein said first aqueous stream is fed to said at least one pervaporation unit without any intervening distillation,
wherein the third aqueous stream (ii) has a water concentration higher than or equal to 95% by weight.

7. The process of claim 1 , wherein the polymeric pervaporation membrane is at least one selected from the group consisting of a hydrophilic polymeric membrane and a lipophilic polymeric membrane.

8. The process of claim 7 , wherein the polymeric pervaporation membrane is at least one hydrophilic polymeric membrane.

9. The process of claim 7 , wherein the at least one hydrophilic polymeric membrane is present and comprises at least one polymer selected from the group consisting of polyvinyl alcohol, a polyvinyl alcohol/polyacrylic acid copolymer, cellulose diacetate, and cellulose triacetate.

10. The process of claim 9 , wherein the at least one polymer is cross-linked.

11. The process of claim 9 , wherein the at least one polymer is selected from the group consisting of polyvinyl alcohol and a polyvinyl alcohol/polyacrylic acid copolymer.

12. The process of claim 7 , wherein the at least one lipophilic polymeric membrane is present and comprises at least one polymer selected from the group consisting of nitrile rubber, neoprene, polydimethylsiloxane (silicon rubber), polyethylene chlorosulfonate, a polysilicone-carbonate copolymer, a fluoroelastomer, a plasticized polyvinyl chloride, a polyurethane, cis-polybutadiene, cis-polyisoprene, polychloroprene, poly(butene-1), an ethylene/propylene copolymer, an ethylene/propylene/diene terpolymer, a polystyrene/butadiene copolymer, a styrene/butadiene/styrene block copolymer, a styrene/ethylene/butylene block copolymer, a thermoplastic polyolefin elastomer, a polyesteramide, and a polyether and polyester block copolymer.

13. The process of claim 12 , wherein the at least one polymer is cross-linked.

14. The process of claim 12 , wherein the at least one polymer is polyalkylsiloxane.

15. The process of claim 1 , wherein the first aqueous stream is fed to the at least one pervaporation unit at a temperature ranging from 20° C. to 100° C.

16. The process of claim 15 , wherein the first aqueous stream is fed to the at least one pervaporation unit at a temperature ranging from 30° C. to 70° C.

17. The process of claim 1 , wherein, on a feeding side (retentate side) of the at least one pervaporation unit, an operating pressure ranges from 0.5 bar to 5 bar.

18. The process of claim 17 , wherein, on the feeding side (retentate side) of the at least one pervaporation unit the operating pressure ranges from 1 bar and 2.5 bar.

19. The process of claim 1 , wherein, on a permeate side of the at least one pervaporation unit, an operating pressure ranges from 0.0005 bar to 0.5 bar.

20. The process of claim 19 , wherein on the permeate side of the at least one pervaporation unit the operating pressure ranges from 0.001 bar to 0.25 bar.

21. The process of claim 1 , wherein a total flow mass ranges from 0.05 kg/(m 2 ×h) to 10 kg/(m 2 ×h).

22. The process of claim 21 , wherein the total flow mass ranges from 0.1 kg/(m 2 ×h) to 8 kg/(m 2 ×h).

23. A process for purifying a first aqueous stream coming from a Fischer-Tropsch reaction, the first aqueous stream comprising an aldehyde, a ketone, an acid, a nitrogenated compound, a sulfurated compound, and traces of metals, the process comprising:
(I) feeding the first aqueous stream to at least one pervaporation unit, wherein the at least one pervaporation unit comprises at least one lipophilic polymeric pervaporation membrane, to obtain two outgoing streams:
(ia) a second aqueous stream enriched in at least one alcohol having from 1 to 8 carbon atoms, with respect to said first aqueous stream, and
(iia) a third aqueous stream enriched in water; and

(II) feeding the second aqueous stream (ia) to at least one pervaporation unit, wherein the at least one pervaporation unit comprises at least one hydrophilic polymeric pervaporation membrane, to obtain two outgoing streams:
(ib) a fourth aqueous stream enriched in at least one alcohol having from 1 to 8 carbon atoms, and
(iib) a fifth aqueous stream (iib) enriched in water,

wherein said first aqueous stream is fed to said at least one pervaporation unit without any intervening distillation.

24. The process of claim 23 , wherein the fourth aqueous stream (ib) is enriched in at least one alcohol having from 2 to 4 carbon atoms.

25. The process of claim 23 , wherein the fourth aqueous stream (ib) has an alcohol concentration higher than or equal to 80% by weight.

26. The process of claim 25 , wherein the fourth aqueous stream (ib) has an alcohol concentration higher than or equal to 95% by weight.

27. The process of claim 23 , wherein the at least one lipophilic polymeric pervaporation membrane comprises at least one polymer selected from the group consisting of nitrile rubber, neoprene, polydimethylsiloxane (silicon rubber), polyethylene chlorosulfonate, a polysilicone-carbonate copolymer, a fluoroelastomer, a plasticized polyvinyl chloride, a polyurethane, cis-polybutadiene, cis-polyisoprene, polychloroprene, poly(butene-1), an ethylene/propylene copolymer, an ethylene/propylene/diene terpolymer, a polystyrene/butadiene copolymer, a styrene/butadiene/styrene block copolymer, a styrene/ethylene/butylene block copolymer, a thermoplastic polyolefin elastomer, a polyesteramide, and a polyether and polyester block

Assignees

• Miglio Roberta
• Carnelli Lino
• Clerici Gabriele Carlo Ettore
• Zennaro Roberto
• Eni Spa

Inventors

• Miglio Roberta
• Carnelli Lino
• Clerici Gabriele Carlo Ettore
• Zennaro Roberto

Classifications

• C02F1/448

  by pervaporation · CPC title

• B01D3/145

  One step being separation by permeation · CPC title

• B01D61/362 Primary

  Pervaporation · CPC title

• B01D2311/04

  Specific process operations in the feed stream; Feed pretreatment · CPC title

• B01D3/14

  Fractional distillation {or use of a fractionation or rectification column} · CPC title