Waste to hydrogen conversion process and related apparatus

Abstract

A reversible electrochemical system includes a first electrode comprising liquid silver metal and a second electrode, said first and second electrodes separated by a oxygen ion-conducting solid electrolyte; a conduit for directing a first reactive material across the second electrode; and a conduit for contacting second reactive material with the first liquid silver electrode, wherein the cell is capable of steam electrolysis when the polarity of the electrodes is selected such that the liquid silver is an anode and the cell is capable of electrical energy generation when the polarity of the electrodes is selected such that the liquid silver is a cathode.

1 . A steam electrolysis system, comprising:
 an oxidizing compartment comprising a liquid metal anode and a reducing compartment comprising a cathode, said oxidizing and reducing compartments separated by an oxygen ion-conducting solid electrolyte;   a conduit for directing steam across the cathode in the reducing compartment; and   a conduit for contacting a carbon feed with the liquid metal anode in the oxidizing compartment.   
   
   
       2 . The electrolysis system of  claim 1 , further comprising:
 a condenser downstream from the oxidizing compartment for separating steam from hydrogen.   
   
   
       3 . The electrolysis system of  claim 1 , wherein the liquid metal anode comprises a metal that is liquid at temperatures greater than 1000K. 
   
   
       4 . The electrolysis system of  claim 3 , wherein the liquid metal anode is selected from the group consisting of silver, copper and tin. 
   
   
       5 . The electrolysis system of  claim 4 , wherein the cathode comprises a cermet. 
   
   
       6 . The electrolysis system of  claim 5 , wherein the cathode is porous. 
   
   
       7 . The electrolysis system of  claim 4 , wherein the oxygen ion-conducting solid electrolyte is selected from the group consisting of rare earth doped zirconia-, ceria-, hafnia-, and thoria-based oxides. 
   
   
       8 . The electrolysis system of  claim 7 , wherein the electrolyte comprises yttria-stabilized zirconia. 
   
   
       9 . The electrolysis cell of  claim 1 , wherein the carbon feed is conductive and is in contact with the anode as a consumable current collector. 
   
   
       10 . A solid oxide fuel cell, comprising:
 a reducing compartment comprising a liquid silver cathode and an oxidizing compartment comprising an anode, said oxidizing and reducing compartments separated by a oxygen ion-conducting solid electrolyte;   a conduit for directing an oxygen source across the cathode in the reducing compartment; and   a conduit for directing a hydrogen source across the anode in the oxidizing compartment; and an energy storage device for storing energy generated during operation of the fuel cell.   
   
   
       11 . The solid oxide fuel cell of  claim 10 , wherein the cathode comprises a cermet. 
   
   
       12 . The solid oxide fuel cell of  claim 10 , wherein the cathode is porous. 
   
   
       13 . The solid oxide fuel cell of  claim 8 , wherein the oxygen ion-conducting solid electrolyte is selected from the group consisting of rare earth doped zirconia-, ceria-, hafnia-, and thoria-based oxides. 
   
   
       14 . The solid oxide fuel cell of  claim 9 , wherein the electrolyte comprises yttria-stabilized zirconia. 
   
   
       15 . A method of producing hydrogen comprising:
 providing an electrolysis system comprising an oxidizing compartment comprising a liquid metal anode and a reducing compartment comprising a cathode, said oxidizing and reducing compartments separated by a oxygen ion-conducting solid electrolyte;   directing steam across the cathode in the reducing compartment; and   contacting a carbon feed with the liquid metal anode in the oxidizing compartment, wherein the steam is reduced at the cathode to hydrogen and the carbon feed is oxidized at the anode.   
   
   
       16 . The method of  claim 11 , wherein the carbon feed comprises carbon-containing waste material. 
   
   
       17 . The method of  claim 12 , wherein the waste material is selected from the group consisting of hydrocarbon waste, agricultural waste, carbonaceous waste and toxic waste. 
   
   
       18 . The method of  claim 12 , wherein the waste material is selected from the group consisting of plastics, polymers, paper, saw dust, carbon and coal dust. 
   
   
       19 . The method of  claim 11 , wherein the carbon feed is introduced into the liquid metal anode as a liquid. 
   
   
       20 . The method of  claim 11 , wherein the carbon feed is introduced into the liquid metal anode as a powder. 
   
   
       21 . The method of  claim 11 , wherein the carbon feed is conductive and is formed into a current collector. 
   
   
       22 . A reversible system, comprising:
 a first electrode comprising liquid silver metal and a second electrode, said first and second electrodes separated by a oxygen ion-conducting solid electrolyte;   a conduit for directing a first reactive material across the second electrode; and   a conduit for contacting second reactive material with the first liquid silver electrode,   wherein the cell is capable of steam electrolysis when the polarity of the electrodes is selected such that the liquid silver is an anode and the cell is capable of electrical energy generation when the polarity of the electrodes is selected such that the liquid silver is a cathode.   
   
   
       23 . The reversible system of  claim 22 , wherein the second electrode comprises a cermet. 
   
   
       24 . The reversible system of  claim 23 , wherein the second electrode is porous. 
   
   
       25 . The reversible system of  claim 22 , wherein the oxygen ion-conducting solid electrolyte is selected from the group consisting of rare earth doped zirconia-, ceria-, hafnia-, and thoria-based oxides. 
   
   
       26 . The reversible system of  claim 25 , wherein the electrolyte comprises yttria-stabilized zirconia. 
   
   
       27 . The reversible system of  claim 22 , wherein the polarity of the system is selected such that the liquid silver electrode is an anode and the second reactive materials is carbon feed. 
   
   
       28 . The reversible system of  claim 27 , wherein the carbon feed is conductive and is in contact with the anode as a consumable current collector. 
   
   
       29 . The reversible system of  claim 27 , wherein the carbon feed comprises carbon-containing waste material. 
   
   
       30 . The reversible system of  claim 29 , wherein the waste material is selected from the group consisting of hydrocarbon waste, agricultural waste, carbonaceous waste and toxic waste. 
   
   
       31 . The reversible system of  claim 29 , wherein the waste material is selected from the group consisting of plastics, polymers, paper, saw dust, carbon and coal dust. 
   
   
       32 . The reversible system of  claim 27 , wherein the carbon feed is introduced into the liquid metal anode as a liquid. 
   
   
       33 . The reversible system of  claim 27 , wherein the carbon feed is introduced into the liquid metal anode as a powder. 
   
   
       34 . A method of reversible operation of a cell, comprising:
 a) providing a cell comprising a first electrode comprising liquid silver metal and a second electrode, said first and second electrodes separated by a oxygen ion-conducting solid electrolyte;   a conduit for directing a first reactive material across the second electrode; and   a conduit for contacting second reactive material with the first liquid silver electrode,   
     in any order,
 b) selecting the polarity of the electrodes such that the liquid silver is an anode; 
 directing steam across the second electrode; and 
 contacting a carbon material with the first liquid silver electrode, wherein the steam is reduced at the cathode to hydrogen and the carbon feed is oxidized at the anode; and 
 c) selecting the polarity of the electrodes such that the liquid silver is a cathode; 
 directing hydrogen across the second electrode; and 
 contacting oxygen with the first liquid silver electrode, wherein the steam is reduced at the cathode to hydrogen and the carbon feed is oxidized at the anode, wherein electrical energy is generated. 
 
   
   
       35 . The method of  claim 34 , wherein the second electrode comprises a cermet. 
   
   
       36 . The method of  claim 34 , wherein the second electrode is porous. 
   
   
       37 . The method of  claim 34 , wherein the oxygen ion-conducting solid electrolyte is selected from the group consisting of rare earth doped zirconia-, ceria-, hafnia-, and thoria-based oxides. 
   
   
       38 . The method of  claim 37 , wherein the electrolyte comprises yttria-stabilized zirconia. 
   
   
       39 . The method of  claim 34 , wherein in step (b) the second reactive material is carbon feed. 
   
   
       40 . The method of  claim 39 , wherein the carbon feed is conductive and is in contact with the anode as a consumable current collector. 
   
   
       41 . The method of  claim 39 , wherein the carbon feed comprises carbon-containing waste material. 
   
   
       42 . The method of  claim 41 , wherein the waste material is selected from the group consisting of hydrocarbon waste, agricultural waste, carbonaceous waste and toxic waste. 
   
   
       43 . The method of  claim 41 , wherein the waste material is selected from the group consisting of plastics, polymers, paper, saw dust, carbon and coal dust. 
   
   
       44 . The method of  claim 39 , wherein the carbon feed is introduced into the liquid metal anode as a liquid. 
   
   
       45 . The method of  claim 39 , wherein the carbon feed is introduced into the liquid metal anode as a powder.