A PROCESS FOR REMOVING SULPHUR COMPOUNDS FROM PROCESS STREAMS

Abstract

A method for removing sulphur compounds from a process stream by contacting the process stream with an aqueous solution containing glycolaldehyde as the predominant compound.

Claims

1.-18. (canceled)

19. A method for removing sulphur compounds from a process stream comprising the step of contacting the process stream with an aqueous solution in which 10-100 wt % of the organic dry matter content of the aqueous solution is glycolaldehyde and 1-30 wt % of the organic dry matter content of the aqueous solution is pyruvaldehyde.

20. The method according to claim 19, wherein 50-95 wt % of the organic dry matter content of the aqueous solution is glycolaldehyde.

21. The method according to claim 19, wherein glycolaldehyde is present in a weight amount of 1-40 times higher than pyruvaldehyde.

22. The method according to claim 19, wherein 0.5-10 wt % of the organic dry matter content of the aqueous solution is acetol.

23. The method according to claim 19, wherein 0.5-5 wt % of the organic dry matter content of the aqueous solution is glyoxal.

24. The method according to claim 23, wherein glycolaldehyde is present in a weight amount of 2-40 times higher than glyoxal.

25. The method according to claim 19, wherein 0-25 wt % of the organic dry matter content of the aqueous solution is formaldehyde.

26. The method according to claim 19, wherein the sulphur compound is hydrogen sulphide (H.sub.2S).

27. The method according to claim 19, wherein the molar ratio of sulphur in the process stream to glycolaldehyde in the aqueous solution is in the range 1:1 to 1:5.

28. A method according to claim 19, wherein the process stream is a fluid selected from the group consisting of natural gas, synthesis gas, LPG, crude oil, diesel, gasoline, jet fuel, kerosene, and water.

29. The method according to claim 19, wherein the contacting of the process stream with the aqueous solution comprises injecting the aqueous solution into wellheads, downholes and/or oil platforms.

30. A method for producing the aqueous solution of claim 19 comprising fragmentation of carbohydrates to produce a fragmentation product.

31. The method according to claim 30, wherein the sugar is selected from one or more of the group consisting of glucose, sucrose, fructose, xylose, mannose, arabinose, ribose, galactose, lactose, tagatose, and combinations thereof.

32. The method according to claim 30, wherein the sugar is fed to the thermolytic fragmentation in an aqueous solution.

33. The method according to claim 30, wherein the fragmentation product is subjected to a purification step.

34. The method according to claim 33, wherein the purification comprises removing formaldehyde from the aqueous solution.

35. A sulphur scavenger obtainable by the method according to claim 30, wherein the sulphur scavenger, based on the organic dry matter content of the aqueous solution, comprises: 10-99 wt % glycolaldehyde, 1-30 wt % pyruvaldehyde, 0-10 wt % acetol, 0-5 wt % glyoxal, and 0-25 wt % formaldehyde.

36. The sulphur scavenger according to claim 35, wherein the aqueous solution is free of formaldehyde.

37. Use of a sulphur scavenger according to claim 35 for scavenging sulphur in a fluid selected from the group consisting of natural gas, synthesis gas, LPG, crude oil, diesel, gasoline, jet fuel, kerosene, and water.

Description

EXAMPLE

[0037] Sodium sulfide nonahydrate is dissolved in water to give a concentration of hydrogen sulfide of 1500 ppm. The pH of the solution is adjusted to approx. 7 by the addition of hydrochloric acid. An amount of oxygenate mixture prepared as described in U.S. Pat. No. 7,094,932 with composition of organic dry matter: glyoxal: 5.5 wt %, pyruvaldehyde: 6.5 wt %, glycolaldehyde: 72.3 wt %, formaldehyde: 11.0 wt %, acetic acid: 1.45 wt %, acetol: 3.5 wt %, is added to the hydrogen sulfide solution giving a hydrogen sulfide to oxygenate molar ratio of 1:1.8. The mixture is allowed to stand for 19 hours at room temperature at which point the hydrogen sulfide concentration in the solution has been reduced to 700 ppm. In a blank experiment, identical to the above experiment except no oxygenate mixture was added, the hydrogen sulfide concentration was determined to be 1400 ppm after 19 hours.