Electrolyser and assembly comprising same, in particular for the production of h2 and o2

Abstract

The present invention relates to an electrolyser for the production of at least one chemical substance, such as hydrogen, oxygen, chlorine or hypochlorous acid, or sodium hydroxide, by electrolysis of pure water or of water containing at least one salt, base and/or acid such as NaCl, H 2 SO 4 , KOH or NaOH, comprising a stack of at least a first and a second consecutive electrolytic cells, each electrolytic cell ( 10 ) comprising; —an anode, —a cathode, —an ion exchange membrane ( 11 ) positioned between the anode and the cathode, the ion exchange membrane ( 11 ) of the first electrolytic cell and of the second electrolytic cell being separated by a bipolar electrode ( 15 ) constituting on the one hand, the anode of the first electrolytic cell and, on the other hand, the cathode of the second electrolytic cell.

1 . An electrolyser for the production of at least one chemical substance, such as dihydrogen, dioxygen, chlorine or hypochlorous acid, or soda, by electrolysis of pure water or of water containing at least one salt, base and/or acid such as NaCl, H 2 SO 4 , KOH or NaOH, comprising a stack of at least a first and a second consecutive electrolytic cell, each electrolytic cell ( 10 ) comprising:
 an anode,   a cathode,   at least one ion-exchange membrane ( 11 ) arranged between the anode and the cathode,   
       the ion-exchange membranes ( 11 ) of the first and second electrolytic cell being separated by a bipolar electrode ( 15 ) constituting on the one hand the anode of the first electrolytic cell and on the other hand the cathode of the second electrolytic cell. 
     
     
         2 . The electrolyser according to  claim 1 , wherein the bipolar electrode ( 15 ) comprises a bipolar plate ( 4 ) all in one piece, the bipolar plate being associated if necessary with at least one grid ( 14 ) and with at least one porous plate ( 12 ). 
     
     
         3 . The electrolyser according to  claim 1 , wherein the bipolar electrode ( 15 ) is entirely in one piece, the bipolar plate ( 4 ), the grids ( 14 ) and the porous plates ( 12 ) being integral with one another prior to installation in the electrolyser. 
     
     
         4 . The electrolyser according to  claim 1 , wherein the bipolar electrode ( 15 ) comprises at least one of the following materials: nickel, iridium, ruthenium, palladium, cadmium, molybdenum, platinum, stainless steel, titanium, tantalum, iron alloy, nickel alloy, lead alloy, and/or a thin layer of tantalum oxide, iridium oxide, ruthenium oxide, lead oxide, ferric oxide, platinum, platinum carbon, palladium, nickel, cadmium, and/or molybdenum. 
     
     
         5 . The electrolyser according to  claim 1 , wherein the anode comprises at least one of the following materials: titanium, tantalum, iridium, iron alloy, lead alloy, and/or a thin layer of tantalum oxide, iridium oxide, ruthenium oxide, lead oxide, and/or ferric oxide. 
     
     
         6 . The electrolyser according to  claim 1 , wherein the cathode comprises at least one of the following materials: nickel, iridium, palladium, cadmium, molybdenum, platinum, titanium, tantalum, iron alloy, lead alloy, nickel alloy and/or a thin layer of platinum, platinum carbon, palladium, nickel, cadmium, and/or molybdenum. 
     
     
         7 . The electrolyser according to  claim 1 , wherein the ion-exchange membrane ( 11 ) comprises boron nitride, notably activated boron nitride. 
     
     
         8 . The electrolyser according to  claim 1 , wherein the ion-exchange membrane ( 11 ) comprises a polymer matrix, notably based on PTFE. 
     
     
         9 . The electrolyser according to  claim 1 , wherein the ion-exchange membrane ( 11 ) has a thickness between 100 and 500 μm. 
     
     
         10 . The electrolyser as claimed in  claim 9 , wherein the electrolyte comprising water and acid, water and a base or water and a salt. 
     
     
         11 . The electrolyser according to  claim 1 , wherein one cell comprising a single ion-exchange membrane between the anode and the cathode. 
     
     
         12 . The electrolyser according to  claim 1 , wherein at least one cell of the stack comprising two ion-exchange membranes ( 11 ), preferably two membranes providing an intermediate chamber between them (I). 
     
     
         13 . The electrolyser according to  claim 1 , wherein at least one cell comprising a nonselective ion-exchange membrane such as a membrane comprising boron nitride, and a selective exchange membrane such as a membrane based on Nafion. 
     
     
         14 . The electrolyser claimed in  claim 12 , comprising means for establishing a circulation of electrolyte in the intermediate chamber (I), notably with a view to withdrawing a substance produced in the electrolyser during operation thereof. 
     
     
         15 . An electrolytic assembly comprising:
 an electrolyser ( 1 ) according to  claim 1 ,   a reservoir, notably a dihydrogen reservoir ( 21 ) for storing the dihydrogen obtained, and   a reservoir, notably a dioxygen reservoir ( 22 ) for storing the dioxygen obtained.   
     
     
         16 . The assembly according to  claim 15 , wherein the electrolyte is stored in each of the two reservoirs. 
     
     
         17 . The assembly according to  claim 16 , wherein having fluid communication between the two reservoirs, preferably at their base, more preferably controlled by a transfer valve (EV 1 ), for maintaining equilibrium of the electrolyte level in the two reservoirs. 
     
     
         18 . A method of production of hypochlorous acid, by means of the electrolyser according to  claim 12 , wherein the anodic chamber of a cell preferably contains water, the cathodic chamber contains water and the intermediate chamber contains brine. 
     
     
         19 . An electrolyser cell, comprising:
 an anode,   a cathode,   two exchange membranes ( 11 ), notably:   a selective exchange membrane and a nonselective exchange membrane ( 11 ), arranged between the anode and the cathode, preferably a nonselective membrane ( 11 ) based on activated boron nitride and preferably a selective membrane based on Nafion, the nonselective membrane preferably protecting the selective membrane from a basic or acidic environment.