Processes and systems for treating sour water

Patent metadata

Field	Value
Publication number	US-2023100630-A1
Application number	US-202218061147-A
Country	US
Kind code	A1
Filing date	Dec 2, 2022
Priority date	Dec 3, 2019
Publication date	Mar 30, 2023
Grant date	—

Abstract

Processes for producing olefins may include electrolyzing an aqueous solution comprising metal chloride, where electrolyzing the aqueous solution causes at least a portion of the metal chloride to undergo chemical reaction to produce a treatment composition comprising hypochlorite. The processes may further include contacting at least a portion of the treatment composition with the sour water at a pH from 8 to 12, where the sour water comprises sulfides and the contacting causes reaction of the sulfides in the sour water with the hypochlorite to produce a treated aqueous mixture comprising at least metal sulfates and metal chlorides, where the metal sulfates are present in the treated aqueous mixture as precipitated solids. The processes may further include separating the precipitated solids from the treated aqueous mixture to produce a treated effluent comprising at least the metal chloride.

First claim

1 . A system for treating sour water, the system comprising:
an electrolyzer comprising at least one anode, at least one cathode, and a power source electrically coupled to the at least one anode and the at least one cathode, the electrolyzer operable to pass an electric current through an aqueous solution comprising metal chloride to produce a treatment composition comprising hypochlorite; a reactor downstream from the electrolyzer, where the reactor is operable to contact at least a portion of the treatment composition comprising the hypochlorite with sour water at a pH from 8 to 12; and a separation device downstream from the reactor, where the separation device is operable to separate precipitated solids from the treated aqueous mixture to produce a solid product comprising metal sulfates and metal carbonates and a treated effluent comprising the metal chloride.

2 . The system of claim 1 , where the aqueous solution and the treated effluent further comprises metal hydroxide.

3 . The system of claim 2 , further comprising a vacuum crystallization system downstream from the separation device, the vacuum crystallization system being operable to crystallize at least a portion of the metal chlorides and metal hydroxides in the treated effluent to form a crystallized product in an aqueous solution.

4 . The system of claim 3 , further comprising a second separation device downstream from the vacuum crystallization system, in which the second separation device is operable to separate the metal chloride and the metal hydroxide from the crystallization effluent to produce a crystallized solid and an ammonium chloride solution.

5 . The system of claim 4 , further comprising an aqueous solution preparation system upstream of the electrolyzer, the aqueous solution preparation system operable to contact the crystallized solid with water to form the aqueous solution.

6 . The system of claim 5 , further comprising a recycle line fluidly coupled to the second separation device or the vacuum crystallization system and to the aqueous solution preparation system, the recycle line operable to recycle the crystallized solid back to the aqueous solution preparation system.

7 . The system of claim 1 , where:
the aqueous solution comprises from 15 percent by weight (wt. %) to 30 wt. % of the metal chloride and 1 wt. % to 10 wt. % the metal hydroxide; and the sour water comprises sulfides and the contacting causes reaction of the sulfides in the sour water with the hypochlorite to produce a treated aqueous mixture comprising at least metal sulfates and metal chlorides, where the metal sulfates are present in the treated aqueous mixture as precipitated solids.

Assignees

• Saudi Arabian Oil Co

Inventors

• Raynel Guillaume Robert Jean-Francois

Classifications

• C02F2101/20

  Heavy metals or heavy metal compounds · CPC title

• C02F1/5236 Primary

  using inorganic agents · CPC title

• C02F2101/101

  Sulfur compounds · CPC title

• C02F2001/5218

  Crystallization · CPC title

• C02F1/5281

  Installations for water purification using chemical agents · CPC title