Water electrolysis system (SOEC) or fuel cell (SOFC) operating under pressure in a tight enclosure with improved regulation

Patent metadata

Field	Value
Publication number	US-10876213-B2
Application number	US-201715998741-A
Country	US
Kind code	B2
Filing date	Feb 15, 2017
Priority date	Feb 16, 2016
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A system for regulating the pressure of a high-temperature electrolysis or co-electrolysis (HTE) reactor or a fuel cell (SOFC) operating under pressure. The operation of the system includes: regulating the DH wet gas flow upstream of one of the chambers so as to ensure the electrochemical stability of the predetermined operating point; regulating the DO gas flow upstream of the at least one second chamber so as to ensure gas scavenging in the at least one second chamber, and in the enclosure; regulating the flow of second gas circulating in the enclosure, downstream of the enclosure, so as to ensure the detection of leaks and safety in relation thereto and to prevent the formation of an explosive atmosphere; and controlling the pressure, by means of the regulation valves arranged downstream of the stack, on the gases, including the wet gas, which are also generally hot.

First claim

The invention claimed is:

1. A system, comprising:
at least one first chamber through which a first gas, which is a gas that is potentially wet, is able to flow;
at least one first supply line that is able to supply an inlet of the first chamber with potentially wet gas up to a maximum operating pressure P max , the first supply line comprising a first flow-rate regulator that is able to regulate a flow rate D H of the first gas between a zero value and a maximum value D H,max ;
at least one second chamber through which a second gas is able to flow;
a seal-tight enclosure in which the first and second chambers are housed, and through which the same second gas is able to flow, the enclosure being able to operate under a pressure of the second gas up to the maximum operating pressure P max ;
at least one second supply line that is able to supply the seal-tight enclosure and an inlet of the second chamber with the second gas, the second supply line comprising a second flow-rate regulator that is able to regulate a flow rate D O of the second gas between a zero value and a maximum value D O,max ;
at least one outlet line that is able to exhaust the second gas from inside the seal-tight enclosure, said outlet line comprising a third flow-rate regulator that is able to regulate a flow rate D purge , of the second gas between a zero value and a maximum value D purge,max ;
pressure sensors (P H , P O ) that are able to measure a pressure in each of the first and second chambers, between atmospheric pressure and the value of the maximum pressure P max ;
at least two regulating valves (V H , V O ) that are arranged outside the enclosure and on outlet lines of the one or more first chambers and of the one or more second chambers, respectively, each valve being able to operate each at a temperature above a condensation temperature of the wet gas at the maximum pressure P max in question, each valve being able to be open from 0% to 100% and having a capacity K v suitable for the maximum pressure P max and for an average flow rate of the gas in question in each of the two outlet lines;
means for heating the lines containing the wet gas to a temperature above the condensation temperature of this wet gas at the maximum pressure P max in question; and
commanding and automatically controlling means for commanding and automatically controlling the regulating valves (V H , V O ) depending on differences in pressure values measured by the pressure sensors so as to obtain a minimum pressure difference between the one or more first chambers and the one or more second chambers.

2. The system as claimed in claim 1 , comprising a condenser for condensing the wet gas, said condenser being arranged downstream of the regulating valve V H on the outlet line of the one or more first chambers.

3. The system as claimed in claim 1 , the commanding and automatically controlling means furthermore being able to command and automatically control the regulators regulating the flow rate D O of the second gas depending on the state of openness of the valves V O for regulating the second gas, in order to prevent states of complete openness or closedness of the valves V O for the second gas.

4. The system as claimed in claim 1 , comprising a high-temperature electrolysis or co-electrolysis (HTE) reactor comprising a stack of elementary solid-oxide (co-)electrolysis cells each comprising an anode, a cathode, and an electrolyte inserted between the anode and the cathode, the cells being electrically connected in series, the stack comprising two electrical terminals for a supply of current to the cells and defining flow chambers for, with respect to the first chambers, a flow of steam and hydrogen or of steam, hydrogen and carbon dioxide (CO 2 ) over the cathodes and flow chambers for, with respect to the second chambers, a flow of air or nitrogen or oxygen or of a mixture of gases containing oxygen over the anodes.

5. The system as claimed in claim 1 , comprising a high-temperature fuel-cell (SOFC) stack comprising a stack of elementary solid-oxide electrochemical cells each comprising an anode, a cathode, and an electrolyte inserted between the anode and the cathode, the cells being electrically connected in series, the stack comprising two electrical terminals for a collection of current from the cells and defining flow chambers for, with respect to the first chambers, a flow of dihydrogen or another fuel gas or of a mixture containing a fuel gas over the anodes and flow chambers for, with respect to the second chambers, a flow of air or nitrogen or oxygen or of a mixture of gases containing oxygen over the cathodes.

6. The system as claimed in claim 1 , wherein the pressure sensors are at least two absolute pressure sensors (P H , P O ) that are each able to measure an absolute pressure in each of the first chambers and in each of the second chambers, respectively.

7. The system as claimed in claim 1 , wherein the one or more pressure sensors (P H ) are one or more absolute pressure sensors P H that are each able to measure an absolute pressure in each of the first chambers, and comprising one or more differential pressure sensors that are able to measure a pressure difference ΔP O =(P O −P H ) between the one or more second chambers and the one or more first chambers, respectively.

8. The system as claimed in claim 1 , furthermore comprising bypass valves V H,bypass , V O,bypass that are each arranged in parallel with the regulating valves V H , V O , respectively.

9. A method for operating the system as claimed in claim 1 , comprising:
a/defining the following operating setpoints:
a1/defining a flow rate D H that corresponds to an amount of potentially wet gas required for a preset electrochemical operating point;
a2/defining a flow rate D O that corresponds to an amount of second gas required for the preset electrochemical operating point and to purge the seal-tight enclosure;
a3/defining a flow rate D purge that corresponds to an amount of second gas required to ensure detection of and safety with respect to leaks and to avoid a formation of an explosive atmosphere in the enclosure;
a4/defining a pressure P setpoint for the preset operating point;
a5/defining a differential pressure ΔP O,setpoint corresponding to a pressure difference between the pressure in the one or more second chambers and in the seal-tight enclosure, and the pressure in the one or more first chambers;
b/ applying the following regulations:
b1/actuating the regulator(s) for regulating the flow rate of the first wet gas, in order to regulate the flow rate D H of the first wet gas;
b2/actuating the regulator(s) for regulating the flow rate of the second gas, in order to regulate the flow rate D O entering into the one or more second chambers and into the enclosure;
b3/actuating the regulator(s) for regulating the flow rate of purge gas, in order to regulate the flow rate D purge of second gas exiting from the enclosure;
b4/actuating the valve V H for regulating the first wet gas in order to regulate the actual pressure P H of the one or more first chambers to the setpoint value P setpoint ; and
b5/actuating the valve V O of the second gas so that the actual differential pressure ΔP O =(P O −P H ) between, on the one hand, the one or more second chambers and in the enclosure and, on the other hand, the one or more first chambers, is regulated depending on a measured error (ΔP O,setpoint −ΔP O ) with respect to the setpoint, so that the pressure P O of the second gas follows that P H of the one or more first chambers with the setpoint differential pressure ΔP O,setpoint .

10. The operating method as claimed in claim 9 , further comprising:
increasin

Assignees

• Commissariat Energie Atomique

Inventors

• Petitjean Marie
• Chatroux Andre

Classifications

• C25B9/73

  of the filter-press type · CPC title

• H01M8/04089

  of gaseous reactants · CPC title

• H01M8/04388

  of anode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04761

  of fuel cell exhausts · CPC title

• C25B1/04 Primary

  by electrolysis of water · CPC title