Electrolyser module

Abstract

Liquid communication means for an electrolyser module comprising a plurality of structural plates each having a sidewall extending between opposite end faces with a half cell chamber opening and at least two degassing chamber openings extending through the structural plate between the opposite end faces, the liquid communication means facilitating liquid communication between the at least two degassing chambers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. application Ser. No. 13 / 609,732 filed Sep. 11, 2012, which is a continuation-in-part of U.S. application Ser. No. 12 / 501,790 filed Jul. 13, 2009, now U.S. Pat. No. 8,308,917, issued Nov. 13, 2012, which claims priority to Canadian Application No. 2637865 filed Jul. 15, 2008. The disclosures of the above applications and patents are herein incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to the design of electrolysers for the production of gases such as hydrogen and oxygen, or hydrogen and nitrogen, or hydrogen and chlorine, and more particularly, to a water electrolyser module and components therefor.BACKGROUND OF THE INVENTION[0003]Electrolysers use electricity to transform reactant chemicals to desired product chemicals through electrochemical reactions, i.e., reactions that occur at electrodes that are in contact with an electrolyte. Hydrogen is a pro...

AI Technical Summary

Benefits of technology

[0082]It is preferable to start operation of the electrolyser module at the intended operating pressure, in order to avoid difficulties with larger gas volumes at lower pressures. Thus, the interior pressure of the electrolyser module is increased to the intended operating pressure prior to initial start up by introducing pressurized inert gas into the electrolyser module. The term initial start up is understood to include any start up after depressurization of the electrolyser module is required. Examples of suitable inert gases are nitrogen, argon and helium. Once the electrolyser module is pressurized with inert gas, operation of the electrolyser module can be started; the product gas is vented until the gas purity reaches acceptable levels, which will depend on the user application.

[0083]It also is preferable that liquid level during non-operational periods is lower than where the gas-liquid passage(s) and the degassed liquid passage(s) in each of the structural plates meets the degassing chamber, but is higher than the top of the half cell chamber. In this way, a break in the electrolyte path between half cell chambers is provided, while ensuring that the half cell chambers remain filled, and the membranes remain fully wetted.

[0084]The fluid flows in a six-cell electrolyser module according to the present invention were modeled by computational fluid dynamics (CFD). For s

Problems solved by technology

For example, the use of a pump adds complexity, capital and operating cost, maintenance requirements, and may adversely affect the availability of the electrolyser module.

The pump generally is operated at all times during module operation at a liquid flow rate corresponding to that required for the maximum nominal gas production rate, resulting in maximum associated power losses.

Although a dual mechanical pump electrolyser module configuration also is disclosed, typically in practical (commercial) electrolyser modules, a single mechanical pump circuit is used to circulate liquid collected from both degassing chambers back to both the cathode half cell chambers and anode half cell chambers; this maintains equal pressures on either side of the membrane in each cell, but typically adversely affects gas purities by introducing the other gas (entrained in the returning liquid) into both the anode and cathode half cell chambers.

Advantages of this design approach are the potential to maintain high gas purities and inherently self-regulating fluid flows; however, the number of cells per cell stack is limited by the pressure drop across the horizontal manifolds in the cell stack and the external piping or tubing, and the available vertic

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