A flow arrangement for an electrolyser, an electrolyser, electrolysis installation, operating method and method of manufacture

Abstract

There is disclosed a flow arrangement 100 for an electrolyser, comprising: first and second porous walls 110, 120, corresponding to first and second electrodes of the electrolyser; an inlet chamber 102 disposed between the first and second porous walls and configured to receive a fluid through an inlet; first and second outlet chambers 130, 140 for retaining respective fluid reaction products of electrolysis. One of, or each of, the porous walls has a discontinuous porous structure comprising a body 116 and a plurality of porous regions 117 extending through the body at discrete locations to permit the fluid to flow from the inlet chamber to the respective outlet chamber, each porous region defining a respective network of flow paths through the body. There is also disclosed an electrolyser and electrolysis installation, methods of operation, and methods of manufacture.

1 . An flow arrangement for an electrolyser comprising a flow arrangement, the flow arrangement comprising:
 first and second porous walls corresponding to first and second electrodes of the electrolyser;   an inlet chamber disposed between the first and second porous walls and configured to receive a fluid through an inlet;   first and second outlet chambers for retaining respective fluid reaction products of electrolysis, separated from the inlet chamber by the first and second porous walls respectively;   wherein one of, or each of, the first and second porous walls has a discontinuous porous structure, wherein the or each porous wall having the discontinuous porous structure:   comprises a body having an inlet side adjacent to the inlet chamber and an outlet side adjacent to the respective outlet chamber, wherein the body is elongate along a longitudinal direction, and has a thickness direction from the inlet side to the outlet side;   comprises a plurality of porous regions extending through the body at discrete locations to permit the fluid to flow from the inlet chamber to the respective outlet chamber,   wherein each porous region defines a respective network of flow paths through the body.   
     
     
         2 . The flow arrangement electrolyser according to  claim 1 , wherein for the or each porous wall having the discontinuous porous structure, each porous region is elongate along a path through the body having a longitudinal component. 
     
     
         3 . The flow arrangement electrolyser according to  claim 2 , wherein for the or each porous wall having the discontinuous porous structure, each porous region is elongate along a path through the body defining a path angle relative to the longitudinal direction of between 20°-80°. 
     
     
         4 . The electrolyser flow arrangement according to  claim 1 , wherein both of the first and second porous walls have the discontinuous porous structure, and wherein at least one property of the discontinuous porous structure differs between the first and second porous walls by a respective minimum offset, selected from the group consisting of:
 a porosity of the respective porous walls, with an associated minimum offset of 0.01;   a macro porosity of the respective porous walls, for each porous wall defined as the porosity of the body of the porous wall in the absence of the porous region, with an associated minimum offset of 0.01;   a micro porosity of the respective porous walls, for each porous wall defined as the porosity of the porous regions, with an associated minimum offset of 0.05;   a pitch by which the respective porous regions are spaced apart, with a minimum offset of 10% relative to a smallest of respective pitches of the porous walls;   an average cross-sectional area of the respective porous regions, each cross-sectional area being determined by a volume of the porous region divided by an extent of the porous region along the thickness direction, with an associated minimum offset of 10%;   an average diameter of the respective porous regions, when each porous region has a circular cross-section normal to the path along which the porous region is elongate, with an associated minimum offset of 10%;   a path angle of the respective porous regions, determined as the angle between the paths along which the porous regions are elongate and the respective longitudinal direction, with an associated minimum offset of 5°; and   a thickness of the porous wall along the respective thickness direction, with an associated minimum offset of 10% relative to a thinnest one of the porous walls.   
     
     
         5 . The electrolyser flow arrangement according to  claim 1 , wherein for the or each porous wall having the discontinuous porous structure:
 the porous regions each have a porosity of between 0.2-0.9.   
     
     
         6 . (canceled) 
     
     
         7 . The electrolyser flow arrangement according to  claim 1 , wherein for the or each porous wall having the discontinuous porous structure:
 a material composition of the porous regions differs from a material composition of the body.   
     
     
         8 . The electrolyser flow arrangement according to  claim 1 , wherein for the or each porous wall having the discontinuous porous structure:
 the body is integrally formed with the plurality of porous regions;   each porous region interfaces with the body at a respective boundary which surrounds the porous region and is defined by a change in porosity between the body and the porous region.   
     
     
         9 . The flow arrangement according to  claim 8 , wherein for the or each porous wall having the discontinuous porous structure:
 a material composition of the body is the same as the material composition of the respective porous regions.   
     
     
         10 . An electrolyser according to  claim 1  for performing continuous electrolysis of an electrolyte fluid electrolyser for performing continuous electrolysis of an electrolyte fluid, wherein the electrolyser comprises a flow arrangement comprising:
 first and second porous walls corresponding to first and second electrodes of the electrolyser; 
 an inlet chamber disposed between the first and second porous walls and configured to receive the electrolyte fluid through an inlet; 
 first and second outlet chambers for retaining respective fluid reaction products of electrolysis, separated from the inlet chamber by the first and second porous walls respectively; 
 wherein one of, or each of, the first and second porous walls has a discontinuous porous structure, wherein the or each porous wall having the discontinuous porous structure: 
 comprises a body having an inlet side adjacent to the inlet chamber and an outlet side adjacent to the respective outlet chamber, wherein the body is elongate along a longitudinal direction, and has a thickness direction from the inlet side to the outlet side; 
 comprises a plurality of porous regions extending through the body at discrete locations to permit the fluid to flow from the inlet chamber to the respective outlet chamber, 
 wherein each porous region defines a respective network of flow paths through the body; and 
 wherein the first and second porous walls provide first and second electrodes of the electrolyser respectively. 
 
     
     
         11 - 12 . (canceled) 
     
     
         13 . The electrolyser according to  claim 10 , wherein for the or each porous wall having the discontinuous porous structure and providing an electrode of the electrolyser:
 the porous regions comprise an electrocatalyst and thereby define an electrocatalytic region of the respective electrode for an electrolysis half-reaction.   
     
     
         14 . The electrolyser according to  claim 13 , wherein
 for the or each porous wall having the discontinuous porous structure and providing an electrode of the electrolyser:   the respective porous regions each comprise a porous medium formed from an electrocatalyst-containing particulate.   
     
     
         15 . The electrolyser according to  claim 13 , wherein for the or each porous wall having the discontinuous porous structure:
 a material composition of the porous regions differs from a material composition of the body;   optionally wherein the body comprises a passive region of the respective electrode to inhibit electrolysis.   
     
     
         16 . The electrolyser according to  claim 10 , wherein for the or each porous wall having the discontinuous porous structure:
 the body is integrally formed with the plurality of porous regions;   each porous region interfaces with the body at a respective boundary which surrounds the porous region and is defined by a change in porosity between the body and the porous region;   the porous regions comprise an electrocatalyst, thereby belonging to an electrocatalytic region of the respective electrode for an electrolysis half-reaction;   the porous regions and the body have a common material composition comprising the electrocatalyst.   
     
     
         17 . The electrolyser according to  claim 13 , wherein for the or each porous wall having the discontinuous porous structure:
 the inlet side of the body is defined by a passive region which is configured to be less electrocatalytically active than the electrocatalytic region;   optionally wherein the passive region comprises a passivating coating defining the inlet side of the body to inhibit electrolysis.   
     
     
         18 . (canceled) 
     
     
         19 . A method of operating an electrolyser, the electrolyser comprising:
 first and second porous walls corresponding to first and second electrodes of the electrolyser;   an inlet chamber disposed between the first and second porous walls and configured to receive a fluid through an inlet;   first and second outlet chambers for retaining respective fluid reaction products of electrolysis, separated from the inlet chamber by the first and second porous walls respectively;   wherein one of, or each of, the first and second porous walls has a discontinuous porous structure, wherein the or each porous wall having the discontinuous porous structure:   comprises a body having an inlet side adjacent to the inlet chamber and an outlet side adjacent to the respective outlet chamber, wherein the body is elongate along a longitudinal direction, and has a thickness direction from the inlet side to the outlet side;   comprises a plurality of porous regions extending through the body at discrete locations to permit the fluid to flow from the inlet chamber to the respective outlet chamber,   wherein each porous region defines a respective network of flow paths through the body;   the method, comprising:   providing an inlet flow of electrolyte fluid to the inlet chamber via the inlet to conduct electrolysis half-reactions at the first and second electrodes provided by the first and second porous walls, to generate respective fluid reaction products;   wherein the electrolyte fluid and/or associated ions flow into the porous regions of the or each electrode having the discontinuous porous structure to react with the respective electrode;   wherein each of the first and second outlet chambers retains the respective fluid reaction product for discharge, and the respective electrode inhibits return flow of the fluid reaction product from the outlet chamber to the inlet chamber.   
     
     
         20 . (canceled) 
     
     
         21 . A method of manufacturing a porous wall having a discontinuous porous structure, for an electrolyser, comprising:
 providing a body for the porous wall, wherein the body is elongate along a longitudinal direction, and has a thickness direction from a first side to a second side;   removing material from the body to form a plurality of open regions, the open regions extending through the body at discrete locations, wherein each open region is elongate along a path through the body having a longitudinal component;   applying an electrocatalyst composition to the body so that it flows into the open regions;   heating the body to perform a heat treatment operation in which an electrocatalyst component of the electrocatalyst composition forms a porous region at each location of the open regions, wherein each porous region defines a respective network of flow paths through the body to permit fluid to flow from the first side of the body to the second side of the body.   
     
     
         22 . The method according to  claim 21 , further comprising a drying operation to vaporise a component of the electrocatalyst composition, conducted after applying the electrocatalyst composition and before the heat treatment operation. 
     
     
         23 . The method according to  claim 21 , wherein the heat treatment operation comprises heating the body to a target temperature of between 150-1000° C. 
     
     
         24 . The method according to  claim 21 , wherein the electrocatalyst composition has a viscosity of from about 1 Pa·s to about 30 Pa·s when applied to the body. 
     
     
         25 . The method according to  claim 21 , wherein the electrocatalyst composition comprises a mixture of an electrocatalyst and liquid when applied to the body. 
     
     
         26 - 30 . (canceled)