Method of removing hydrogen-sulfide from water

Patent metadata

Field	Value
Publication number	US-2016355414-A1
Application number	US-201615171429-A
Country	US
Kind code	A1
Filing date	Jun 2, 2016
Priority date	Jun 2, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A method for removing hydrogen sulfide from a liquid stream is described. The method includes contacting the liquid stream including a first amount of hydrogen sulfide with a first side of a porous gas-liquid separation membrane. The hydrogen sulfide moves through the pores of the membrane from the first side to a second, opposite side of the membrane. The method further includes contacting a receiving fluid with the second, opposite side of the porous membrane to receive the hydrogen sulfide. The liquid stream is thus converted to a reduced-sulfide liquid stream having a second amount of hydrogen sulfide that is less than the first amount of hydrogen sulfide. A method for removing ammonia from a liquid stream is also described.

First claim

What is clamed is:

1 . A method for removing hydrogen sulfide from a liquid stream, the method comprising:
contacting a first side of a porous, gas-liquid separation membrane with a liquid stream comprising a first amount of hydrogen sulfide; and contacting a second, opposite side of the separation membrane with a receiving fluid having a lower concentration of hydrogen sulfide than the liquid stream, wherein the hydrogen sulfide moves through the pores of the membrane from the first side to the second side, to provide a reduced-sulfide liquid stream having a second amount of hydrogen sulfide that is less than the first amount of hydrogen sulfide in the liquid stream.

2 . The method of claim 1 , wherein the second amount of hydrogen sulfide is less than or equal to 10% (e.g. 0.01% to 10%) of the first amount of hydrogen sulfide, preferably less than or equal to 5% (e.g.0.01% to 5%) of the first amount of hydrogen sulfide, more preferably less than or equal to 1% (e.g. 0.01% to 1%) of the first amount of hydrogen sulfide.

3 . The method of claim 1 or 2 , wherein the first amount of hydrogen sulfide is 1 to 30,000 milligrams of hydrogen sulfide per 1 liter of the liquid stream.

4 . The method of any of claims 1 to 3 , where the liquid stream has a pH of 2 to 9, preferably 4 to 7.

5 . The method of any of claims 1 to 4 , wherein the membrane is a hydrophobic polymeric membrane comprising polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyetheretherketone, or a combination comprising at least one of the foregoing.

6 . The method of any of claims 1 to 5 , wherein the pores of the membrane are 0.005 to 1 micrometers, preferably 0.01 to 0.2 micrometers.

7 . The method of any of claims 1 to 6 , wherein the receiving fluid comprises water and an additive reactive with the hydrogen sulfide to provide a sulfur-containing reaction product, wherein the sulfur-containing reaction product has a composition different from hydrogen sulfide, optionally wherein the additive reactive with the hydrogen sulfide comprises sodium hydroxide, potassium hydroxide, hydrogen peroxide, sodium hypochlorite, sodium chlorite, an organic amine reactive with hydrogen sulfide, or a combination comprising at least one of the foregoing.

8 . The method of any of claims 1 to 6 , wherein the receiving fluid comprises a sweep gas, and the hydrogen sulfide is removed as a vapor.

9 . The method of claim 8 , wherein the sweep gas comprises air, nitrogen, fuel gas, methane, or a combination comprising at least one of the foregoing.

10 . The method of any of claims 1 to 7 further comprising separating the sulfur-containing reaction product from the receiving solution to form a purified receiving fluid and a sulfur-rich stream, optionally wherein the separating comprises centrifuging, filtering, decanting, or a combination comprising at least one of the foregoing.

11 . The method claim 10 , further comprising recycling the purified receiving fluid.

12 . The method of any of claims 1 to 11 , further comprising pretreating the liquid stream prior to contacting the separation membrane, wherein the pretreating comprises pressurizing the liquid stream, softening, heating, adjusting the pH, a chemical treatment, filtering, or a combination comprising at least one of the foregoing.

13 . The method of any of claims 1 to 12 , wherein
the liquid stream further comprises ammonia;
the ammonia moves through the pores of the membrane from the first side to the second, opposite side of the membrane;
the receiving fluid receives the ammonia; and
the reduced-sulfide liquid stream further comprises a second amount of ammonia that is less than the first amount of ammonia.

14 . The method of any of claims 1 to 13 wherein a pressure differential is maintained across the membrane whereby the said second side is at a lower pressure than the said first side.

15 . The method of claim 14 wherein the pressure differential is at least 200 mbar, such as between 200 and 4,000 mbar.

16 . The method of claim 15 wherein the pressure differential is between 300 and 2,000 mbar.

17 . The method of claim 16 wherein the pressure differential is between 400 and 1,400 mbar.

18 . The method of any of claims 1 to 17 wherein the pressure on said second side of the membrane is maintained below atmospheric pressure.

19 . The method of claim 18 wherein the pressure on the said second side of the membrane is maintained below atmospheric pressure by drawing air through the aqueous receiving fluid thereby stripping hydrogen sulfide from the receiving fluid whilst also maintaining sub atmospheric pressure on said second side of the membrane.

20 . A method for removing ammonia from a liquid stream, the method comprising:
contacting a first side of a porous, gas-liquid separation membrane with a liquid stream comprising a first amount of ammonia; and contacting a second, opposite side of the separation membrane with a receiving fluid having a lower concentration of ammonia than the liquid stream, wherein the ammonia moves through the pores of the membrane from the first side to the second side, to provide a reduced-ammonia liquid stream having a second amount of ammonia that is less than the first amount of ammonia in the liquid stream.

Assignees

• Conocophillips Co

Inventors

• Janson Arnold
• Gharfeh Samir
• Adham Samer
• Chowdhury Zaid
• Minier-Matar Joel

Classifications

• C02F11/122

  using filter presses (C02F11/123 takes precedence) · CPC title

• B01D2311/04

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

• C02F2101/16

  Nitrogen compounds, e.g. ammonia · CPC title

• B01D2311/13

  Use of sweep gas · CPC title

• C02F1/448 Primary

  by pervaporation · CPC title