Phased charging and discharging in capacitive desalination

Patent metadata

Field	Value
Publication number	US-2017144902-A1
Application number	US-201514951180-A
Country	US
Kind code	A1
Filing date	Nov 24, 2015
Priority date	Nov 24, 2015
Publication date	May 25, 2017
Grant date	—

Abstract

A system combines complete, ultra-thin cells into a monolithic and robust framework necessary for desalination applications which yields orders of magnitude faster desalination. The electrode pairs are located so that a flow of feed water flows through or around the electrode pairs with the flow perpendicular to sequentially applied electric potentials. The system is controlled to charge the series of electrode pairs sequentially or phased. That means the charging of the second electrode pair is delayed with regard to the charging of the first electrode pair and the charging of a third electrode pair is delayed with respect to the charging of the second electrode pair.

First claim

1 . A method of charging a capacitive deionization system that utilizes multiple porous electrode pairs in series, wherein the multiple porous electrode pairs include a first electrode pair, a second electrode pair, and an additional electrode pair, comprising the steps of:
flowing water containing salt through or next to the multiple porous electrode pairs, sequentially applying an electrical potential to the corresponding multiple electrode pairs as said water flows through or over the multiple electrode pairs, and controlling said step of sequentially applying an electrical potential to the corresponding multiple electrode pairs as said water flows through the multiple electrode pairs to provide a delay between applying an electrical potential to the first electrode pair and applying an electrical potential to the second electrode pair, and to provide a delay between applying an electrical potential to the second electrode pair and applying an electrical potential to the additional electrode pair.

2 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs in series of claim 1 wherein said step of controlling said step of sequentially applying an electrical potential to multiple electrode pairs as said water flows through or over the multiple electrode pairs such that the at least one time delay between electrode potentials are determined in part by the rate of water flowing through the electrodes.

3 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs arranged such that water containing salt flows in a serial fashion through or over the electrodes of claim 1 wherein said step of controlling said step of sequentially applying an electrical potential to multiple electrode pairs as said water flows through the multiple electrode pairs results in a traveling wave of electrode charge state which correlates with the motion of the flowing water containing salt through or next to the multiple electrode pairs.

4 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs arranged such that water containing salt flows in a serial fashion through or over the electrodes of claim 1 wherein the water flows into the first electrode pair, the water flows into subsequent electrode pairs wherein said step of controlling said step of sequentially applying electrical potentials to multiple electrode pairs as said water flows through or over the multiple electrode pairs includes providing a time delay between electric potentials applied to first and second electrode pairs which is different than the one or more subsequent time delays associated with the potential applied to any third or subsequent electrode pairs.

5 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs in series of claim 4 wherein said time delay is an equal time delay.

6 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs arranged such that water containing salt flows in a serial fashion through or over the electrodes of claim 4 wherein said time delays are not all equal to each other.

7 . The method of charging a capacitive deionization system that utilizes multiple electrode pairs arranged such that water containing salt flows in a serial fashion through or over the electrodes of claim 1 where at least one of different electric potentials applied to the multiple electrode pairs is varied so as to achieve a desired value of electrical current between at least one electrode pair.

8 . A method of capacitive desalination for removing salt from water,
comprising the steps of: providing a first cell having a first pair of porous electrodes, providing a second cell having a second pair of porous electrodes, providing a third cell having a third pair of porous electrodes, flowing the water containing the salt through said first pair of porous electrodes in said first cell, flowing the water containing the salt through said second pair of porous electrodes in said first cell, flowing the water containing the salt through said third pair of porous electrodes in said third cell, applying a first electric potential to said first pair of porous electrodes in said first cell, applying a second electric potential to said second pair of porous electrodes in said second cell, and applying a third electric potential to said third pair of porous electrodes in said third cell, wherein said step of applying a second electric potential to said second pair of porous electrodes in said second cell is delayed with regard to said step of applying a first electric potential to said first pair of porous electrodes in said first cell, and wherein said step of applying a third electric potential to said third pair of porous electrodes in said third cell is delayed with regard to said step of applying a second electric potential to said second pair of porous electrodes in said second cell, thereby removing the salt from the water.

9 . The method of capacitive desalination for removing salt from water of claim 8 wherein said steps of applying a second electric potential to said second pair of porous electrodes in said second cell and applying a third electric potentials to said third pair of porous electrodes are delayed by an equal amount of time.

10 . The method of capacitive desalination for removing salt from water of claim 8 wherein steps of applying a second electric potential to said second pair of porous electrodes in said second cell and applying a third electric potentials to said third pair of porous electrodes is delayed by an un-equal amount of time.

11 . The method of capacitive desalination for removing salt from water of claim 8 wherein said step of applying a first electric potential to said first pair of porous electrodes includes
providing a time delay in applying a first electric potential to said first pair of porous electrodes in said step of flowing the water containing the salt through or next to said first pair of porous electrodes in said first cell, and
providing a time delay in applying a second electric potential to said second pair of porous electrodes in said step of flowing the water containing the salt through or next to said second pair of porous electrodes in said first cell, and
providing a time delay in applying a third electric potential to said third pair of porous electrodes in said step of flowing the water containing the salt through or next to said third pair of porous electrodes in said first cell.

12 . The method of capacitive desalination for removing salt from water of claim 11 wherein said time delays are equal.

13 . The method of capacitive desalination for removing salt from water of claim 11 wherein said time delays are un-equal time delays.

14 . The method of capacitive desalination for removing salt from water of claim 8 wherein said step of providing a second cell having a second pair of porous electrodes includes providing a distance between said first pair of porous electrodes and said second pair of porous electrodes and wherein said step of providing a third cell having a third pair of porous electrodes includes providing a distance between said second pair of porous electrodes and said third pair of porous electrodes.

15 . A capacitive desalination apparatus for removing salt from water, comprising:
a first cell having a first pair of porous electrode means, a second cell having a second pair of porous electrode means, a third cell having a third pair of porous electrode means, means for flow

Assignees

• L Livermore Nat Security Llc
• Univ Leland Stanford Junior

Inventors

• Stadermann Michael
• Qu Yatian
• Santiago Juan G
• Hemmatifar Ali

Classifications

• C02F1/008

  Control or steering systems not provided for elsewhere in subclass C02F · CPC title

• C02F1/4691 Primary

  Capacitive deionisation · CPC title

• C02F2103/08

  Seawater, e.g. for desalination · CPC title

• C02F2201/46135

  Voltage · CPC title