Electrolyzers and systems comprising the same

Abstract

Disclosed herein are systems comprising one or more electro-synthesizer units (ESU) and at least one hydrogen compensation unit (HCU), wherein the system is configured to efficiently loop hydrogen within the ESU and compensate by any lost hydrogen with HCU.

1 . A system comprising:
 one or more electro-synthesizer units (ESU) and   at least one hydrogen compensation unit (HCU);   wherein the one or more ESU are in fluid and electrical communication with at least one HCU;   wherein the one or more ESUs comprises:   a) a first chamber comprising a first volume of a first solution that is in electrical communication with a first electrode;   b) a second chamber comprising a second volume of a second solution that is in electrical communication with a second electrode;   c) a third chamber positioned between and in fluid communication with the first and the second chamber, wherein the third chamber comprises a third volume of a third solution; and   wherein the at least one HCU comprises   i) a fourth chamber comprising a fourth volume of a fourth solution that is in electrical communication with a fourth electrode; and   ii) a fifth chamber comprising a fifth volume of a fifth solution that is in electrical communication with a fifth electrode;   wherein optionally, the fourth chamber and the first chamber are the same such that one shared chamber between the one or more ESUs and at least one HCU is formed;   wherein the one or more ESUs are acid/base electrolyzers and the at least one HCU is an alkaline electrolyzer.   
     
     
         2 . The system of  claim 1 , wherein
 the first solution is an alkaline solution, and the first electrode is a cathode, and wherein the cathode generates a first hydrogen gas and a hydroxide; and/or   wherein the second solution is an acid solution and the second electrode is a gas diffusion anode.   
     
     
         3 . The system of  claim 1 , wherein the second chamber comprises a first compartment and a second compartment, wherein the first compartment comprises the second solution and the second compartment comprises a hydrogen gas, and wherein the first and the second compartments are separated by the anode. 
     
     
         4 . The system of  claim 3 , wherein the second compartment of the second chamber receives the hydrogen gas generated in the first chamber. 
     
     
         5 . The system of  claim 1 , wherein when the first chamber and the fourth chamber are the one shared chamber, the fourth electrode is either:
 i) a shared electrode, i.e., the fourth electrode and the first electrode are the same one electrode shared between the ESU unit and HCU unit; or   ii) an additional electrode to the first electrode such that the one shared chamber comprises two separate electrodes: the first electrode and the fourth electrode, which are electrically isolated from each other;   and/or   wherein when the first chamber and the fourth chamber are the one shared chamber, the fourth volume of the fourth solution equals to the first volume of the first solution, and the first solution and the fourth solution are the same.   
     
     
         6 . The system of  claim 1 , wherein the fourth solution is alkaline, and the fifth solution is an oxygen-enriched alkaline. 
     
     
         7 . The system of  claim 1 , wherein the fourth electrode generates a second hydrogen gas. 
     
     
         8 . The system of  claim 7 , wherein the second hydrogen gas is fed into the second chamber. 
     
     
         9 . The system of  claim 1 , wherein the fifth electrode is an anode. 
     
     
         10 . The system of  claim 1 , wherein at least one of the one or more ESU and the at least one HCU are physically coupled. 
     
     
         11 . The system of  claim 1 , wherein the system is a multistack of the one or more ESU and at least one HCU, or
 wherein the multistack comprises a ratio of ESU to HCU of 10:1 to 500:1, or   wherein the multistack comprises a ratio of ESU to HCU of 10:2 to 500:2.   
     
     
         12 . The system of  claim 11 , wherein
 the at least one HCU is positioned at at least one end of the multistack, or   wherein the at least one HCU is positioned within the multistack between two or more ESUs;   
       and/or
 wherein the two or more HCUs are present, each of the two or more HCUs is adjacent to each other; 
 
       and/or
 wherein the one or more ESUs and the at least one HCU are coupled in a parallel configuration; 
 
       and/or
 wherein one or more ESUs and the at least one HCU are coupled in a series configuration. 
 
     
     
         13 . The system of  claim 1 , wherein the first chamber is separated from the third chamber with one or more cation exchange membranes (CEM). 
     
     
         14 . The system of  claim 1 , wherein the second chamber is separated from the third chamber with one or more anion exchange membranes (AEM). 
     
     
         15 . The system of  claim 1 , wherein the third solution comprises one or more inorganic salts comprising chlorides, sulfates, nitrates, phosphates, citrates, formates, lactates, tartrates, malates, fumarates, oxalates, succinates, gluconates, ascorbates, acetates of alkaline metals and/or alkaline-earth metals, or mixtures thereof. 
     
     
         16 . The system of  claim 1 , wherein the system further comprises a degasser. 
     
     
         17 . The system of  claim 16 , wherein the degasser receives a flow comprising the first hydrogen gas and/or second hydrogen gas if formed, and where the degasser separates the first hydrogen gas and/or second hydrogen from the flow, and wherein the degasser comprises one or more membranes configured to separate a gas from a liquid; or wherein the degasser is gravity-based, centrifugation-based, vortex-based, vacuum-based, or any combination thereof. 
     
     
         18 . The system of  claim 16 , wherein the degasser further comprises at least one moisture removing element. 
     
     
         19 . The system of  claim 1 , wherein the system further comprises a hydrogen storage unit, wherein the hydrogen storage unit stores the first hydrogen gas and/or second hydrogen gas if formed before it is fed into the second chamber. 
     
     
         20 . The system of  claim 1 , wherein the system is a recirculated-in-a-loop flow system.