# US 2014/0197033 A1 · Device and process for improved recovery of deionised water through capactive deionisation cell

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- Number: US 2014/0197033 A1
- Document ID: US20140197033A1
- Status: Published application
- Kind: A1
- Application number: 14/235,928
- Filed: 2012-07-18
- Published: 2014-07-17
- Earliest claimed: 2011-08-04
- Inventors: Tinto Johnichan Alencherry; Venkataraghavan Rajanarayana
- Web page: https://patentgrep.com/patent/US20140197033A1

## CPC

- C02F 1/4691: {Capacitive deionisation}
- C02F 1/008: {Control or steering systems not provided for elsewhere in subclass C02F}
- C02F 2201/005: Valves
- C02F 2201/46145: Fluid flow
- C02F 2209/003: Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process
- C02F 2209/005: Processes using a programmable logic controller [PLC]
- C02F 2209/05: Conductivity or salinity
- C02F 2301/046: Recirculation with an external loop
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)

## Abstract

Disclosed is a process for improved recovery of deionised water from a feed water stream, comprising the steps of: (i) delivering the feed water stream in to a capacitive deionisation cell; (ii) measuring the salt concentration of the water exiting the capacitive deionisation cell; (iii) collecting the water exiting the cell, when the salt concentration is lower than a predetermined lower set point, to prepare purified water or rejecting the water exiting the cell when the salt concentration is higher than a predetermined upper set point; wherein the water exiting the cell is recycled with the feed water stream when the salt concentration of the water exiting the cell is between the lower set point and the upper set point. By this process the waste water produced during capacitive deionization can be recycled so as to improve total recovery of water as well as to enhance the life of the electrodes of the capacitive deionisation cell.

## Claims

### Claim at position 1

1-6. (canceled)

### Claim 7

A device for improved recovery of deionised water from feed water stream comprising:
(i) means to input feed water stream into a capacitive deionization cell;
(ii) a power supply capable of applying pre-programmed timed cycles of positive potentials, negative potentials and shorting the cell;
(iii) a meter for measuring the salt concentration of the water exiting the cell;
(iv) a solenoid valve downstream of the meter;
(v) an electronic processor;
characterized in that the valve is a four way valve and electronic processor is programmed to receive the salt concentration value of the water exiting the cell from said meter and actuate the valve to separate the water into one of three streams where the first stream is for collection of purified water when the salt concentration is below a predetermined lower set point, a second stream for rejection of water when the salt concentration is above a predetermined upper set point and a third stream for recycling of water back into the input feed water stream when the salt concentration is between said lower set point and said upper set point.

### Claim 8

(canceled)

### Claim 9 (depends on 1)

A device as claimed in claim 1 wherein said upper set point is not higher than the salt concentration of the feed water stream.

### Claim 10 (depends on 1)

A device as claimed in claim 1 wherein the upper set point is higher than 500 ppm.

### Claim 11 (depends on 1)

A device as claimed in claim 1 wherein the upper set point is lower than 1500 ppm.

### Claim 12 (depends on 1)

A device as claimed in claim 1 wherein the lower set point is lower than 300 ppm.

### Claim 13 (depends on 1)

A device as claimed in claim 1 wherein the lower set point is higher than 100 ppm.

### Claim 14 (depends on 1)

A device as claimed in claim 1 wherein said meter is a conductivity meter.