High temperature electrolyzer (HTE) including a plurality of cells, having improved operation in the event of breakage of at least one cell and during ageing

Abstract

A process of electrolyzing water at high temperatures implemented by a cell stack reactor, including: a) simultaneously circulating water vapour at each cathode and at each anode as a leaching gas, temperatures of the water vapour at an inlet of each anode and each cathode being lower than high temperatures at which electrolysis is carried out and the water vapour circulating at the anode being at an overpressure with respect to the cathode; b) upon starting the electrolysis, supplying electrical power having a substantially constant electrical voltage across terminals of the stack and maintaining same. In event of breakage of one or more cells, complete destruction of the stack is avoided and high production efficiency is maintained, and efficiency is maintained during ageing.

Description

TECHNICAL FIELD[0001]The invention relates to a process of electrolysing water at high temperatures (HTE), also known as high temperature vapour electrolysis (HTVE), with a view to producing hydrogen.[0002]It also relates to a reactor for implementing said process.[0003]More particularly, it relates to an improvement in the reliability of operation and the efficiency of high temperature electrolysers (HTE), in the event of potential breakages of one or more cells.[0004]In addition, it relates to an improvement in the efficiency of said HTE electrolysers, during ageing or in other words after a considerable time of use.PRIOR ART[0005]An electrolyser comprises a plurality of elementary cells formed of a cathode and an anode separated by an electrolyte, the elementary cells being electrically connected in series by means of interconnecting plates interposed, in general, between an anode of an elementary cell and a cathode of the following elementary cell. An anode-anode connection foll...

AI Technical Summary

Benefits of technology

The invention provides a solution to operate high temperature electrolyser without significant efficiency loss due to potential breakages of cells. This is achieved without the need for active compensation management. The solution ensures that the ageing of cells does not adversely affect hydrogen production efficiency. Instead, the reserve of cell surface is over-sized and serves the electrolysis when cells age. This ensures the conversion rate and efficiency of cells remain correct.

Problems solved by technology

These cells are on the one hand fragile and may thus break at any moment and, on the other hand, they age and thus produce less hydrogen locally.

These two phenomena run counter to the industrial requirement of large volume hydrogen production.

The drawbacks of these solutions are that this requires an active management with the use of costly electrical cabinets and that, above all, the energy efficiency of the HTE electrolyser concerned by the breakage(s) is reduced.

Images