Electricity generation

Patent metadata

Field	Value
Publication number	US-10177396-B2
Application number	US-201314646191-A
Country	US
Kind code	B2
Filing date	Nov 18, 2013
Priority date	Nov 20, 2012
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A method for generating electricity comprising the steps:
(A) passing a concentrated ionic solution through a first pathway in a reverse electrodialysis unit comprising a membrane stack having electrodes and alternating cation and anion exchange membranes; and
(B) passing a dilute ionic solution through a second pathway in said reverse electrodialysis unit, whereby solute from the concentrated solution in the first pathway passes through the membranes to the dilute solution in the second pathway, thereby generating electricity;

wherein the concentration of solute in the dilute ionic solution as it enters the reverse electrodialysis unit is at least 0.03 mol/l.

First claim

The invention claimed is:

1. A method for generating electricity comprising the steps:
(A) passing a concentrated ionic solution through a first pathway in a reverse electrodialysis unit comprising a membrane stack having electrodes and alternating cation and anion exchange membranes; and
(B) passing a dilute ionic solution through a second pathway in said reverse electrodialysis unit, whereby solute from the concentrated solution in the first pathway passes through the membranes to the dilute solution in the second pathway, thereby generating electricity;
wherein:
(i) the concentration of solute in the dilute ionic solution as it enters the reverse electrodialysis unit is at least 0.03 mol/l; and
(ii) the ionic solutions comprise water and a salt which has solubility in water at 20° C. of at least 8 mol/kg water.

2. The method according to claim 1 wherein the concentration of solute in the dilute ionic solution as it enters the reverse electrodialysis unit is at least 0.05 mol/l solvent.

3. The method according to claim 1 wherein the ionic solutions comprise water and a salt, wherein the salt comprises a cation selected from sodium, potassium, lithium, caesium, rubidium and/or ammonium and an anion selected from azide, bromide, carbonate, chloride, chlorate, fluoride, iodide, hydrogen carbonate, nitrate, nitrite, perchlorate, thiocyanate, thiosulphate, acetate and/or formate.

4. The method according to claim 1 wherein one or both of the ionic solutions comprise water and at least 0.02 mol/l of a solute other than sodium chloride.

5. The method according to claim 1 wherein the dilute and/or concentrated ionic solution comprises a water-miscible organic solvent.

6. The method according to claim 1 which further comprises the step (C) of regenerating the concentrated and dilute ionic solutions from the solutions exiting from the reverse electrodialysis unit and recycling said regenerated concentrated and dilute solutions back through said respective first and second pathways in the reverse electrodialysis unit.

7. The method according to claim 1 which is performed such that the following equation is satisfied:
S 1/ S 2> Y
wherein:
S1 is the concentration of solute in mol/l in the concentrated ionic solution as it enters the reverse electrodialysis unit;
S2 is the concentration of solute in mol/l in the dilute ionic solution as it enters the reverse electrodialysis unit; and
Y is at least 30.

8. The method according to claim 1 wherein the flow rate of the ionic solutions through the pathways is less than 4 cm/s.

9. The method according to claim 1 wherein:
(i) the concentration of solute in the dilute ionic solution as it enters the reverse electrodialysis unit is at least 0.05 mol/l solvent;
(ii) one or both of the ionic solutions comprise water and at least 0.02 mol/l of a solute other than sodium chloride;
(iii) the flow rate of the ionic solutions through the pathways is less than 4 cm/s; and
(iv) wherein the method is performed such that the following equation is satisfied:
wherein:
S1 is the concentration of solute in mol/l in the concentrated ionic solution as it enters the reverse electrodialysis unit;
S2 is the concentration of solute in mol/l in the dilute ionic solution as it enters the reverse electrodialysis unit; and
Y is at least 30.

10. The method according to claim 9 which further comprises the step (C) of regenerating the concentrated and dilute ionic solutions from the solutions exiting from the reverse electrodialysis unit and recycling said regenerated concentrated and dilute solutions back through said respective first and second pathways in the reverse electrodialysis unit.

11. The method according to claim 1 wherein at least half of the cation exchange membranes comprise an ionically-charged polymeric layer obtained from a curable composition comprising:
(i) 2.5 to 70 wt % crosslinker comprising at least two acrylamide groups;
(ii) 20 to 65 wt % curable ionic compound comprising one ethylenically unsaturated group and at least one anionic group;
(iii) 5 to 45 wt % solvent; and
(iv) 0 to 10 wt % of free radical initiator; and

wherein at least half of the anion exchange membranes comprise an ionically-charged polymeric layer obtained from a curable composition comprising:
(i) 2.5 to 70 wt % crosslinker comprising at least two acrylamide groups;
(ii) 12 to 65 wt % curable ionic compound comprising one ethylenically unsaturated group and at least one cationic group;
(iii) 10 to 70 wt % solvent; and
(iv) 0 to 10 wt % of free radical initiator.

Assignees

• Fujifilm Mfg Europe Bv
• Fujifilm Mfg Europe Bv

Inventors

• Van Baak Willem

Classifications

• H01M8/1009

  with one of the reactants being liquid, solid or liquid-charged (H01M8/12 takes precedence) · CPC title

• H01M8/227 Primary

  Dialytic cells or batteries; Reverse electrodialysis cells or batteries · CPC title

• H01M8/18

  Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells · CPC title

• Y02E60/50

  Fuel cells · CPC title