A continuous process for sustainable production of hydrogen

Patent metadata

Field	Value
Publication number	US-2021261407-A1
Application number	US-201917260991-A
Country	US
Kind code	A1
Filing date	Jul 18, 2019
Priority date	Jul 19, 2018
Publication date	Aug 26, 2021
Grant date	—

Abstract

The disclosure provides a method of producing hydrogen. The method comprises conducting a thermochemical reaction by contacting a metal, or an alloy thereof, with steam to produce a metal oxide and/or a metal hydroxide and hydrogen. The method then comprises contacting the metal oxide and/or the metal hydroxide produced in the thermochemical reaction with water or a basic aqueous solution to produce a solution comprising a metal ion. Finally, the method comprises conducting an electrochemical reaction by applying a voltage across an anode and a cathode, whereby at least a portion of the cathode contacts the solution comprising the metal ion, to produce hydrogen, oxygen and the metal, or the alloy thereof.

First claim

1 . A method of producing hydrogen, the method comprising:
conducting a thermochemical reaction by contacting a metal, or an alloy thereof, with steam to produce a metal oxide and/or a metal hydroxide and hydrogen; contacting the metal oxide and/or the metal hydroxide produced in the thermochemical reaction with water or a basic aqueous solution to produce a solution comprising a metal ion; and conducting an electrochemical reaction by applying a voltage across an anode and a cathode, whereby at least a portion of the cathode contacts the solution comprising the metal ion, to produce hydrogen, oxygen and the metal, or the alloy thereof.

2 . A method of producing hydrogen, the method comprising:
contacting a metal oxide and/or a metal hydroxide with water or a basic aqueous solution to produce a solution comprising a metal ion; conducting an electrochemical reaction by applying a voltage across an anode and a cathode, whereby at least a portion of the cathode contacts the solution comprising the metal ion, to produce hydrogen, oxygen and a metal, or an alloy thereof; and conducting a thermochemical reaction by contacting the metal, or the alloy thereof, produced in the electrochemical reaction with steam to produce the metal oxide and/or the metal hydroxide and hydrogen.

3 . The method according to claim 1 , wherein the electrochemical reaction is conducted repeatedly, or continuously.

4 . (canceled)

5 . The method according to claim 1 , wherein the thermochemical reaction is conducted continuously, or repeatedly.

6 . (canceled)

7 . The method according to claim 1 , wherein the metal, or the alloy thereof, is a transition metal, a p-block metal, an f-block metal, or an alloy thereof, optionally wherein the metal, or the alloy thereof, is selected from the group consisting of tin, lead, thallium, selenium, bismuth, zinc, copper, iron, nickel, cobalt, manganese, titanium, molybdenum, cadmium, chromium, vanadium, silver, rhodium, platinum, palladium, iridium, osmium, rhenium, ruthenium, lanthanum, zirconium, cerium, gadolinium, yttrium, holmium, samarium, and terbium.

8 . (canceled)

9 . The method according to claim 7 , wherein the metal, or the alloy thereof, is zinc or tin.

10 . The method according to claim 1 , wherein the metal, or the alloy thereof, is contacted with the steam at a temperature of between 100° C. and 700° C.

11 . The method according to claim 1 , wherein the method comprises agitating the metal, or the alloy thereof, while it is being contacted with the steam.

12 . The method according to claim 1 , wherein the method comprises condensing unreacted steam from a gaseous mixture obtained from the thermochemical reaction.

13 . The method according to claim 1 , wherein the method comprises contacting the metal oxide and/or the metal hydroxide with the basic aqueous solution and the basic aqueous solution comprises a base, and the base is an Arrhenius base, a Lewis base, or a Bronsted-Lowry base, optionally wherein the base is an Arrhenius base and comprises an alkali metal or alkaline earth metal hydroxide.

14 . (canceled)

15 . The method according to claim 1 , wherein the method comprises contacting the metal oxide and/or the metal hydroxide with the basic aqueous solution, and the basic aqueous solution comprises a concentration of between 0.5 and 8.5 M of a base.

16 . The method according to claim 1 , wherein the method comprises contacting the metal oxide and/or the metal hydroxide with the basic aqueous solution, and the metal oxide and/or the metal hydroxide is contacted with the basic aqueous solution in a sufficient quantity to produce the solution comprising the metal ion, wherein the metal ion is present at a concentration of between 0.001 and 1 M.

17 . The method according to claim 1 , wherein the method comprises contacting the metal oxide and/or the metal hydroxide with water, and the metal oxide and/or metal hydroxide is contacted with water in a sufficient quantity to produce the solution comprising the metal ion, wherein the metal ion is present at a concentration of between 0.2 and 5 M.

18 . The method according to claim 1 , wherein the anode and the cathode are disposed in an undivided electrochemical cell.

19 . The method according to claim 1 , wherein the anode and the cathode are disposed in an electrochemical cell, and the electrochemical cell comprises a membrane disposed between the anode and the cathode dividing the cell into two portions.

20 . The method according to claim 19 , wherein the method comprises disposing the solution comprising the metal ion in a cathode portion of the cell, such that at least a portion of the cathode contacts the solution comprising the metal alloy and the method further comprises disposing a further electrolyte in an anode portion of the cell, such that at least a portion of the anode contacts the further electrolyte, optionally wherein the further electrolyte comprises a basic aqueous solution.

21 . (canceled)

22 . The method according to claim 1 , wherein the method comprises applying a voltage of between 1 and 8 V across the anode and cathode.

23 . The method according to claim 1 , wherein the method comprises causing a current of between 0.5 and 10 A to flow through the anode, cathode and the solution comprising the metal ion.

24 . An apparatus for producing hydrogen, the apparatus comprising:
a thermochemical reactor, configured to hold a metal, or an alloy thereof, therein, the thermochemical reactor comprising a feed means configured to feed steam into the thermochemical reactor and thereby convert the metal, or the alloy thereof, into a metal oxide and/or a metal hydroxide; and an electrochemical cell comprising an anode and a cathode, and configured to receive a solution comprising a metal ion, such that at least a portion of the cathode contacts the solution comprising the metal ion.

25 . The apparatus according to claim 24 , wherein the apparatus is configured to prevent the metal, the alloy thereof or the metal oxide and/or the metal hydroxide from escaping from the thermochemical reactor while a thermochemical reaction is being conducted therein, optionally wherein the apparatus comprises a container configured to hold the metal, or the alloy thereof, therein and to be placed in the thermochemical reactor, wherein the feed means is configured to feed the steam directly into the container and the container comprises a mesh configured to allow gases to flow out of the container while being further configured to prevent the metal, the alloy thereof or the metal oxide and/or the metal hydroxide from being removed from the container.

26 . (canceled)

Assignees

• Univ Surrey

Inventors

• Amini Horri Bahman
• Gu sai

Classifications

• C01B3/10 Primary

  by reaction of water vapour with metals · CPC title

• C25C1/16

  of zinc, cadmium or mercury · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title

• C01G1/02

  Oxides · CPC title

• B01J19/2465

  externally, i.e. the mixture leaving the vessel and subsequently re-entering it · CPC title