System for high-temperature reversible electrolysis of water comprising a hydride tank coupled with the electrolyser

Patent metadata

Field	Value
Publication number	US-11542610-B2
Application number	US-201716333299-A
Country	US
Kind code	B2
Filing date	Sep 18, 2017
Priority date	Sep 19, 2016
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

A system for high-temperature reversible electrolysis of water, characterised in that it includes: a high-temperature reversible electrolyser, configured to operate in SOEC (solid oxide electrolyser cell) mode to produce hydrogen and store electricity, and/or in SOFC (solid oxide fuel cell) mode to withdraw hydrogen and produce electricity; a hydride tank, thermally coupled with the reversible electrolyser, the system being configured to allow the recovery of heat released by the hydride tank during hydrogen absorption in order to produce pressurised steam intended for entering the reversible electrolyser in SOEC mode, and to allow the recovery of heat released by the one or more outgoing streams from the reversible electrolyser in SOFC mode so as to allow the desorption of hydrogen from the hydride tank.

First claim

What is claimed is:

1. A system for high-temperature reversible electrolysis of water, comprising:
a high-temperature reversible electrolyser, configured to operate in a solid-oxide electrolyser mode, for the production of hydrogen and thus the storage of electricity, and/or according to a solid-oxide fuel cell mode, for the consumption of hydrogen and thus the withdrawal of electricity, said reversible electrolyser comprising an enclosure and a stack of basic solid-oxide electrochemical cells contained within the enclosure, wherein the enclosure is configured to enable the reversible electrolyser to operate under a pressure of between 2 and 15 bars,
a hydride tank, thermally coupled with said reversible electrolyser, configured to store hydrogen in the form of hydrides in solid-oxide electrolyser mode of said reversible electrolyser and/or to release hydrogen in solid-oxide fuel cell mode of said reversible electrolyser,
a primary air circuit comprising:
a first heat exchanger,
a heat recovery element comprising a second heat exchanger, and
a third heat exchanger, intended to: (1) cool a total stream mixed by a mixer suitable for mixing an air stream by means of a compressed air stream; and (2) preheat the compressed air stream by means of the total stream mixed by the mixer suitable for mixing the air stream to form an air stream entering the reversible electrolyser, and
a cooling device configured to cool an air stream leaving the third heat exchanger when the system is configured to operate in solid-oxide fuel cell mode and is a compressed air recirculation system,
the system being configured to allow, when the reversible electrolyser is configured to operate in a solid-oxide electrolyser mode, a recovery of heat released by the hydride tank during the absorption of hydrogen in order to produce pressurized steam intended to enter the reversible electrolyser, and to allow, when the reversible electrolyser is configured to operate in a solid-oxide fuel cell mode, a recovery of heat released by at least one stream leaving the reversible electrolyser to enable the desorption of hydrogen from the hydride tank.

2. The system according to claim 1 , wherein each basic solid-oxide electrochemical cell in the stack is formed by a cathode, an anode, and an electrolyte inserted between the cathode and the anode, and a plurality of electrical and fluidic interconnectors each arranged between two adjacent basic solid-oxide electrochemical cells.

3. The system according to claim 1 , wherein the reversible electrolyser is configured to operate in a solid-oxide electrolyser mode, and the system then comprises:
a steam generator, intended to produce the pressurized steam for the reversible electrolyser by means of the heat released by the hydride tank, during absorption of the hydrogen, and supplied to the steam generator by means of a heat transfer fluid.

4. The system according to claim 3 , wherein the system also comprises:
one or more solid-oxide electrolyser mode heat exchangers allowing water at an inlet of the system to be preheated and/or the pressurized steam entering the reversible electrolyser to be superheated, by means of hydrogen and oxygen streams leaving the reversible electrolyser.

5. The system according to claim 4 , wherein the system comprises one or more solid-oxide electrolyser mode heat exchangers upstream and downstream of the steam generator for allowing the water at the inlet of the system to be preheated and the pressurized steam entering the reversible electrolyser to be superheated, respectively, by means of the hydrogen and oxygen streams leaving the reversible electrolyser.

6. The system according to claim 3 , wherein the system also comprises:
a condenser, coupled to a phase separator, intended to receive unreacted steam in the reversible electrolyser and dihydrogen produced by the reversible electrolyser and to condense unreacted water so that it can be recycled in the system.

7. The system according to claim 3 , wherein the system also comprises:
a compression pump, intended to compress water at an inlet of the system to a pressure of between 2 and 15 bars.

8. The system according to claim 3 , wherein the system also comprises:
an electrical heating element upstream of the reversible electrolyser, providing an additional superheating of the pressurized steam.

9. The system according claim 6 , wherein the system also comprises:
a dryer, upstream of the hydride tank and downstream of the phase separator, intended to allow the humidity contained in the dihydrogen to be removed before storage in the hydride tank.

10. The system according to claim 1 , wherein the reversible electrolyser is configured to operate in a solid-oxide fuel cell mode, and wherein the system is a compressed air recirculation system, consisting of a dihydrogen circuit and the primary air circuit.

11. The system according to claim 10 , wherein the dihydrogen circuit comprises:
a mixer suitable for mixing the hydrogen coming from the hydride tank with unconsumed hydrogen in the reversible electrolyser over a pressure range of 2 to 15 bars,
a first dihydrogen circuit heat exchanger, intended to preheat a dihydrogen stream entering the reversible electrolyser by means of a dihydrogen stream leaving the reversible electrolyser,
a heat recovery element comprising a second dihydrogen circuit heat exchanger, intended to recover heat from the dihydrogen stream leaving the reversible electrolyser by means of at least one heat transfer fluid.

12. The system according to claim 11 , wherein the dihydrogen circuit further comprises a third dihydrogen circuit heat exchanger, intended to cool the dihydrogen stream leaving the heat recovery element comprising the second dihydrogen heat exchanger by a hydrogen stream leaving a phase separator, allowing for recovery of water produced.

13. The system according to claim 1 , wherein:
the first heat exchanger of the primary air circuit is configured to preheat an air stream entering the reversible electrolyser by means of an air stream leaving the reversible electrolyser,
the heat recovery element comprising the second heat exchanger of the primary air circuit is configured to recover heat coming from the air stream leaving the reversible electrolyser by means of at least one heat transfer fluid.

14. The system according to claim 1 , wherein the mixer is suitable for mixing the air stream leaving the heat recovery element comprising the second heat exchanger with supplemental oxygen forming a total stream of air entering the reversible electrolyser.

15. The system according to claim 1 , wherein the primary air circuit further comprises
a compression pump, configured to compress air leaving the cooling device to form the compressed air stream.

16. A process for storing electricity and/or for withdrawing electricity by high-temperature reversible electrolysis of water, wherein the process is implemented by means of a system for high-temperature reversible electrolysis of water according to claim 1 , and wherein the process comprises the steps of:
when the pressurized reversible electrolyser is configured to operate in a solid-oxide electrolyser mode, recovering the heat released by the hydride tank during absorption of the hydrogen in order to produce pressurized steam intended to enter the reversible electrolyser, and
when the pressurized reversible electrolyser is configured to operate in a solid-oxide fuel cell mode, recovering the heat released by the at least one stream leaving the reversible electrolyser in order to allow the desorption of the hydrogen f

Assignees

• Commissariat Energie Atomique

Inventors

• Lacroix Vincent
• Chaise Albin
• Cren Julie
• Reytier Magali
• Roux Guilhem

Classifications

• H01M8/04216 Primary

  characterised by the choice for a specific material, e.g. carbon, hydride, absorbent · CPC title

• Y02E60/50

  Fuel cells · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title