System and method for recovery of CO
A system and method for recovery of CO 2 includes an aqueous capture device having a capture solution. The aqueous capture device is arranged to receive gas and to capture components from the gas including at least CO 2 . An electrodialysis unit in operative connection with the capture device performs an electrodialysis operation on the capture solution including at least the CO 2 , wherein a CO 2 rich process stream and a regenerated capture solution are generated from the capture solution including at least the CO 2 . The CO 2 rich process stream is a pressurized process stream at a pressure which maintains the CO 2 substantially within the CO 2 rich process stream, while in the electrodialysis unit. In another alternative, at least the pH of the capture stream is controlled.
1. A system for recovery of CO 2 comprising:
an aqueous capture device including a capture solution, the aqueous capture device arranged to receive gas and to capture components from the gas including at least CO 2 ;
an electrodialysis unit in operative connection with the capture device to perform an electrodialysis operation on the capture solution including at least the CO 2 ; and
monitors for monitoring pH of the system,
wherein:
a CO 2 rich process stream and a regenerated capture solution are generated from the capture solution including at least the CO 2 , the regenerated capture solution being sent back to the aqueous capture device,
the CO 2 rich process stream is a pressurized process stream at a pressure which maintains the CO 2 in a solution state substantially within the CO 2 rich process stream, while in the electrodialysis unit,
the CO 2 rich process is a buffered process stream having a pH ranging from about 3 to 4 while in the electrodialysis unit, and
the capture solution is a buffered process stream having a pH ranging from about 8 to about 10 while in the electrodialysis unit.
2. The system according to claim 1 wherein the system is a closed loop system.
3. The system according to claim 1 , further including a controller to control the flow rate of the capture solution, dependent on signals provided from the monitors.
4. The system according to claim 1 wherein the electrodialysis unit is a bipolar membrane electrodialysis unit.
5. The system according to claim 1 , wherein the aqueous capture device is a pressure aqueous capture device, which operates at a pressure high enough for operation of the electrodialysis unit, which is a bipolar membrane electrodialysis unit.
6. The system according to claim 1 , further including, a gas evolution/separation tank in operative connection with the electrodialysis unit and configured to receive the CO 2 rich process stream, the CO 2 rich process stream being at least partially de-pressurized and CO 2 gas being removed, the CO 2 depleted process stream being sent back to the electrodialysis unit.
7. The system of claim 1 , wherein:
the capture solution is an aqueous carbonate/bicarbonate solution, MX;
the electrodialysis unit comprises at least one membrane capable of transporting carbonate/bicarbonate ions; and
the electrodialysis unit is configured so as to transport carbonate/bicarbonate ions X − from the capture solution across the at least one membrane into the CO 2 rich process stream.
8. A method for recovering CO 2 comprising:
receiving, in an aqueous capture device, a gas;
capturing at least portions of the gas including at least CO 2 by a capture solution in the aqueous capture device;
performing an electrodialysis operation on the capture solution by an electrodialysis unit; and
monitoring at least the pH of the capture solution and the CO 2 rich process stream,
wherein:
a CO 2 rich process stream and a regenerated capture solution are generated from the capture solution including at least CO 2 ,
the CO 2 rich process stream is a pressurized process stream at a pressure which maintains the CO 2 in a solution state substantially within the CO 2 rich process stream while in the electrodialysis unit,
the CO 2 rich process stream is a buffered process stream having a pH ranging from about 3 to about 4 while in the electrodialysis unit, and
the capture solution is a buffered process stream having a pH ranging from about 8 to about 10 while in the electrodialysis unit.
9. The method according to claim 8 , further including:
moving the regenerated capture solution back to the aqueous capture device, the regenerated capture solution being substantially depleted of CO 2 ;
at least partially de-pressurizing the CO 2 rich process stream by a gas evolution/separation tank to remove CO 2 from the process stream; and
moving the CO 2 depleted process stream back through the electrodialysis unit.
10. The method according to claim 9 wherein a pressure is applied to the capture solution which is sufficient to substantially eliminate evolving of the CO 2 from the CO 2 rich process stream while the CO 2 rich process stream is being processed by the electrodialysis unit.
11. The method according to claim 8 wherein the pressure of the CO 2 rich process stream is between 2-200 atm.
12. The method according to claim 8 further providing a buffered process stream within the electrodialysis unit.
13. The method of claim 8 , wherein:
the capture solution is an aqueous carbonate/bicarbonate solution, MX;
the electrodialysis unit comprises at least one membrane capable of transporting carbonate/bicarbonate ions; and
the electrodialysis unit is configured so as to transport carbonate/bicarbonate ions X − from the capture solution across the at least one membrane into the CO 2 rich process stream.