Electrochemcial treatment of saline wasterwater with captured CO
Methods of separating water, salt, CO 2 , and crude oil from wastewater, the methods comprising: providing gas/oil separation system that produces a waste saline water stream and a CO 2 stream; providing an electrochemical cell having an anode, a cathode, and three electrodialytic compartments; feeding a fresh water stream to the anode to produce H + and O 2 ; feeding the waste CO 2 stream and O 2 to the cathode to produce bicarbonate (HCO 3 —) and hydroxide ions (OH − ); feeding the waste saline water stream to a center electrodialytic compartment; wherein the sodium Na + from the waste saline water stream reacts with the bicarbonate to form NaHCO 3 and the chloride (Cl − ) from the waste saline water stream reacts with the H + to produce hydrochloric acid; and producing salt and desalinated water.
1 . A method of separating water, salt, CO 2 , and crude oil from wastewater, the method comprising:
producing a salt water stream and a gas stream from a gas/oil separation system;
feeding the gas stream into a low pressure gas treatment system to produce a treated CO 2 stream;
feeding the salt water stream into a water-oil separator to produce a waste saline water stream comprising sodium (Na + ) and chloride (Cl − );
combining the waste saline water stream and the treated CO 2 stream to produce a water/CO 2 stream;
feeding the water/CO 2 stream to an electrochemical cell having an anode, a cathode, and three electrodialytic compartments;
feeding a fresh water stream to the anode to produce H + and O 2 ;
feeding the treated CO 2 stream and O 2 to the cathode to produce bicarbonate (HCO 3 —) and hydroxide ions (OH − );
feeding the waste saline water stream to a center electrodialytic compartment;
wherein the sodium (Na + ) from the waste saline water stream reacts with the bicarbonate to form NaHCO 3 and the chloride (Cl − ) from the waste saline water stream reacts with the H + to produce hydrochloric acid; and
producing salt and desalinated water.
2 . The method of claim 1 , wherein the cathode comprises a Pt/C catalyst.
3 . The method of claim 1 , wherein the anode comprises titanium.
4 . The method of claim 1 , wherein the gas/oil separation system comprises a degassing tank, dehydrator, and a crude stabilizer.
5 . The method of claim 4 , wherein the gas/oil separation system produces refined crude oil.
6 . The method of claim 1 , wherein the method further comprises producing dry salt.
7 . The method of claim 1 , wherein the waste saline water stream does not comprise hydrogen disulfide.
8 . The method of claim 1 , wherein the electrochemical cell comprises ion exchange membranes.
9 . A method of separating water, salt, CO 2 , and crude oil from wastewater comprising:
separating a wastewater feed from an oil refinery into a gas stream comprising CO 2 and a salt water stream;
treating the gas stream to produce a treated CO 2 stream;
separating oil from the salt water stream to produce a saline water stream;
combining the saline water stream with the treated CO 2 stream to produce a water/CO 2 stream; and
feeding the water/CO 2 stream to an electrochemical cell to produce salt and desalinated water.
10 . The method of claim 9 , further comprising:
separating the wastewater feed into a crude oil stream by a low pressure trap; and
feeding the crude oil stream to an oil refinery comprising a degassing tank, a dehydrator, and a crude stabilizer.
11 . The method of claim 10 , wherein the low pressure trap produces a first salt water stream, the degassing tank produces a second salt water stream, and the dehydrator produces a third salt water stream.
12 . The method of claim 11 , wherein the first salt water stream, the second salt water stream, and the third salt water stream combine to form the salt water stream.
13 . The method of claim 10 , further comprising, by electrostatic coalescence, separating an emulsion of salt water and wet crude oil in the dehydrator to produce a dehydrator salt water stream and a dehydrator oil stream.
14 . The method of claim 13 , further comprising combining the dehydrator salt water stream with the salt water stream before entering an oil/water separator to produce the saline water stream.