Sour water treatment

Patent metadata

Field	Value
Publication number	US-11247919-B2
Application number	US-202016878372-A
Country	US
Kind code	B2
Filing date	May 19, 2020
Priority date	May 19, 2020
Publication date	Feb 15, 2022
Grant date	Feb 15, 2022

Abstract

A system and method of treating sour water, including providing sour water having hydrosulfide ions and a carbon-containing compound to an anodic chamber of an electrolyzer vessel, converting the hydrosulfide ions into sulfate ions in the anodic chamber via an oxido half-reaction of a first oxido-reduction reaction and generating carbon dioxide in the anodic chamber via an oxido half-reaction of a second oxido-reduction reaction associated with the carbon-containing compound. The technique includes reacting the carbon dioxide with hydroxide ions in the anodic chamber to generate bicarbonate ions. The technique includes discharging an anodic chamber solution having the sulfate ions and the bicarbonate ions from the electrolyzer vessel from the anodic chamber.

First claim

What is claimed is:

1. A method of treating sour water, comprising:
providing sour water comprising hydrosulfide ions and a carbon-containing compound to an anodic chamber of an electrolyzer vessel, the electrolyzer vessel comprising the anodic chamber and a cathodic chamber separated by a diaphragm;
generating, via an electric power source, an electric potential between an anode in the anodic chamber and a cathode in the cathodic chamber;
converting the hydrosulfide ions into sulfate ions in the anodic chamber via an oxido half-reaction of a first oxido-reduction reaction;
generating carbon dioxide in the anodic chamber via an oxido half-reaction of a second oxido-reduction reaction associated with the carbon-containing compound;
reacting the carbon dioxide with hydroxide ions in the anodic chamber to generate bicarbonate ions;
discharging an anodic chamber solution from the electrolyzer vessel from the anodic chamber as a discharged anodic-chamber solution comprising the sulfate ions and the bicarbonate ions;
removing bicarbonate ions and water from the discharged anodic-chamber solution to give a processed discharged anodic-chamber solution having a greater concentration of sulfate ions than in the discharged anodic-chamber solution; and
adding sulfate ions to the processed discharged anodic-chamber solution.

2. The method of claim 1 , comprising adding a metal hydroxide to the anodic chamber to maintain pH of at least 7.5 in the electrolyzer vessel, wherein the diaphragm comprises a cation-exchange diaphragm, and wherein the sour water comprises ammonium hydrosulfide.

3. The method of claim 2 , wherein the metal hydroxide comprises sodium hydroxide, and wherein the discharged anodic-chamber solution comprises sodium bicarbonate comprising the bicarbonate ions.

4. The method of claim 1 , wherein adding the sulfate ions comprises adding sodium sulfate to the processed discharged anodic-chamber solution.

5. The method of claim 1 , wherein adding the sulfate ions comprises adding sulfate ions discharged from a second sour-water treatment system comprising a second electrolyzer vessel without a diaphragm or membrane.

6. The method of claim 1 , wherein removing the bicarbonate ions comprises removing the bicarbonate ions from the discharged anodic-chamber solution as a first permeate in a first nanofiltration system comprising membranes giving a first retentate comprising the sulfate ions.

7. The method of claim 6 , wherein removing the water comprises removing the water as a second permeate from the first retentate via a second nanofiltration system comprising membranes giving a second retentate comprising the processed discharged anodic-chamber solution.

8. A method of treating sour water, comprising:
providing sour water comprising hydrosulfide ions and a carbon-containing compound to an anodic chamber of an electrolyzer vessel, the electrolyzer vessel comprising the anodic chamber and a cathodic chamber separated by a diaphragm;
generating, via an electric power source, an electric potential between an anode in the anodic chamber and a cathode in the cathodic chamber;
converting the hydrosulfide ions into sulfate ions in the anodic chamber via an oxido half-reaction of a first oxido-reduction reaction;
generating carbon dioxide in the anodic chamber via an oxido half-reaction of a second oxido-reduction reaction associated with the carbon-containing compound;
reacting the carbon dioxide with hydroxide ions in the anodic chamber to generate bicarbonate ions;
discharging an anodic chamber solution from the electrolyzer vessel from the anodic chamber as a discharged anodic-chamber solution comprising the sulfate ions and the bicarbonate ions;
removing bicarbonate ions and water from the discharged anodic-chamber solution to give a processed discharged anodic-chamber solution having a greater concentration of sulfate ions than in the discharged anodic-chamber solution;
providing the processed discharged anodic-chamber solution to the cathodic chamber of the electrolyzer vessel;
converting the sulfate ions into sulfite ions in the cathodic chamber via a reduction half-reaction of the first oxido-reduction reaction; and
discharging a cathodic chamber solution comprising the sulfite ions as a discharged cathodic-chamber solution.

9. The method of claim 8 wherein the discharged cathodic-chamber solution comprises sodium sulfite comprising the sulfite ions, the sodium sulfite dissolved in the discharged cathodic-chamber solution.

10. The method of claim 8 , comprising:
removing water from the discharged cathodic-chamber solution to give a slurry comprising solid metal sulfite; and
filtering the solid metal sulfite from the slurry giving filtrate comprising sulfite ions.

11. The method of claim 10 , wherein the solid metal sulfite comprises solid sodium sulfite, and wherein the filtrate comprising sulfite ions comprises ammonium sulfite.

12. The method of claim 1 , wherein the second oxido-reduction reaction comprises an oxido-reduction reaction of the carbon-containing compound.

13. The method of claim 12 , wherein the carbon-containing compound comprises a phenolic compound.

14. The method of claim 1 , wherein the second oxido-reduction reaction comprises an oxido-reaction of an ion from the carbon-containing compound.

15. The method of claim 14 , wherein the carbon-containing compound comprises hydrogen cyanide, and wherein the ion is a cyanide ion.

16. The method of claim 1 , comprising reacting hydrogen cyanide with hydroxide ions in the anodic chamber to give cyanide ions, wherein the carbon-containing compound comprises the hydrogen cyanide.

17. The method of claim 1 , wherein the carbon-containing compound comprises a first carbon-containing compound that is hydrogen cyanide and a second carbon-containing compound that is a phenolic compound.

Assignees

• Saudi Arabian Oil Co

Inventors

• Raynel Guillaume Robert Jean-Francois

Classifications

• B01D61/029

  Multistep processes comprising different kinds of membrane processes selected from reverse osmosis, hyperfiltration or nanofiltration · CPC title

• B01D61/0271

  comprising multiple nanofiltration steps · CPC title

• B01D61/08

  Apparatus therefor · CPC title

• C02F2201/46115

  Electrolytic cell with membranes or diaphragms · CPC title

• C02F2101/101

  Sulfur compounds · CPC title