Electrochemistry method having improved efficiency and associated electrochemical reactor such as a high temperature electrolyser (EHT)

Abstract

An electrochemistry method to produce a reaction gas of a lesser molar mass than that of an initial constituent of gas or vapor, according to which the gas or vapor of the initial constituent is made to flow, and the reaction gas is recovered in the path in which the initial constituent is made to flow. At least one vortex is created in a zone upstream from the reaction gas recovery zone, wherein the vortex can separate the produced reaction gas from the initial constituent still present to subject the initial constituent to an electrochemical process in the upstream zone. In a high-temperature water electrolysis application according to the method, by the vortex, the produced hydrogen is separated from the surplus steam to subject the surplus stream to an electrolytic process within the electrolyser itself.

Description

TECHNICAL FIELD[0001]The invention concerns an electrochemistry method to produce a reaction gas of a lesser molar mass than that of the initial constituent(s) in the form of gas or vapour, according to which the gas or vapour of the initial constituent(s) is made to flow, and the reaction gas is recovered in the path in which the initial constituent(s) is / are made to flow.[0002]It relates to the improvement of the efficiency of such a method.[0003]The principal application with which the invention is concerned is electrolysis of water at high temperature (EHT), also called high-temperature steam electrolysis (EVHT).PRIOR ART[0004]An electrochemical reactor includes multiple elementary cells formed by a cathode and an anode separated by an electrolyte, where the elementary cells are electrically connected in series by means of interconnecting plates which are generally interposed between an anode of an elementary cell and a cathode of the next elementary cell. An anode-anode connect...

AI Technical Summary

Benefits of technology

[0019]According to the invention, means to create a vortex are therefore incorporated into the high-temperature electrolyser itself, which therefore favour the output of the hydrogen, and which slow the output of the steam by ejection to outside the vortex.

[0021]Due to this integration it is possible to envisage manufacturing a high-temperature electrolyser (EHT) with an inlet for steam and a single outlet for the produced hydrogen, since the surplus steam in the vicinity of the outlet is once again transformed into hydrogen. An electrochemical reactor for electrolysis of water thus completely transforms the steam provided at the inlet, provided that the steam remains for a sufficiently long time. Therefore, by creating one or more vortices, the water molecules will be kept for a longer period in the active electrochemical reaction zone by centrifugation; and they will have an increased possibility of being transformed into hydrogen.

[0023]Advantageously, in order to improve performance, i.e. the electrochemical efficiency, multiple vortices in parallel or in series relative to one another are created in the zone upstream from the outlet end.

[0027]The means to create the vortex / vortices advantageously consist of holes pierced in the at least one interconnecting plate upstream from the outlet end of the cathodic compartments. This solution is simple to implement and can be applied easily in all types of interconnecting plates.

Problems solved by technology

Indeed, to favour an average production density, steam is usually deliberately produced in excess quantities, which occurs to the detriment of the attaining of a high rate of steam consumption (or high hydrogen conversion rate).

A disadvantage of the first option is a reduction of average production, whereas a disadvantage of the second option is an implementation (the steam circuit which must be manufactured) which may be complex.

The disadvantages of high-temperature electrolysers according to the state of the art, as described above, can therefore be summarised as follows: their efficiency is not perfect due to the fact that steam remains at the outlet, and their operation requires the use of additional downstream means to separate the hydrogen produced from the steam left over from the electrolysis reaction itself.

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