Electricity Generation
AssigneeFujifilm Manufacturing Europe B.V.
InventorWillem Van Baak
Life of this patent
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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.
Claims24
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.
The method according to any one of the preceding claims 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.
The method according to any one of the preceding claims 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, chlorate, fluoride, iodide, nitrate, nitrite, perchlorate, thiocyanate, thiosulfate, acetate and/or formate.
The method according to any one of the preceding claims wherein the ionic solutions comprise water and a salt which has solubility in water at 20° C. of at least 8 mol/kg water.
The method according to any one of the preceding claims wherein the dilute and/or concentrated ionic solution comprises a water-miscible organic solvent.
The method according to any one of the preceding claims wherein the ionic solutions comprise water and a salt, wherein the salt comprises sodium bromide, sodium chlorate, sodium iodide, sodium nitrate, sodium nitrite, sodium formate, sodium perchlorate, potassium carbonate, potassium formate, potassium acetate, potassium fluoride, potassium iodide, potassium nitrite, potassium thiosulfate, potassium thiocyanate, lithium nitrate, lithium nitrite, lithium acetate, ammonium formate, ammonium acetate, ammonium iodide, ammonium nitrate, ammonium thiosulfate and/or ammonium thiocyanate.
The method according to any one of the preceding claims 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.
The method according to any one of the preceding claims which is performed such that the following equation is satisfied:
- S1/S2>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.
The method according to any one of the preceding claims wherein the flow rate of the ionic solutions through the pathways is less than 4 cm/s.
The method according to any one of the preceding claims wherein at least half of the membranes have a thickness, including the support (when present) of less than 250 μm.
The method according to any one of the preceding claims 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.
The method according to any one of the preceding claims 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.
A device for generating electricity comprising:
- (A) a reverse electrodialysis unit comprising a membrane stack having electrodes, alternating cation and anion exchange membranes, a first pathway through the reverse electrodialysis unit for a concentrated ionic solution, and a second pathway through the reverse electrodialysis unit for a dilute ionic solution;
- (B) means for introducing a concentrated ionic solution into said first pathway;
- (C) a means for introducing a dilute ionic solution into said second pathway, 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;
- (D) optionally a means for heating the concentrated ionic solution to a temperature higher than the dilute ionic solution;
- (E) a means for regenerating concentrated and dilute ionic solutions from the solutions exiting from the reverse electrodialysis unit;
- and
- (F) a recycling means for recycling said regenerated concentrated and dilute solutions back to said first and second pathways in the reverse electrodialysis unit;
- wherein the concentration of solute in the dilute ionic solution as it enters the reverse electrodialysis unit is at least 0.03 mol/l.
Dependencies are inferred from the claim text.