High pressure water electrolysers

Agranat V., Zhubrin S., Maria A., Hinatsu J., Stemp M. Kawaji M., CFD modelling of gas-liquid flow and heat transfer in a high pressure water electrolyser system. Proc. of FEDSM, July 17-20, Miami (Florida) 2006. 

Fig, 5.6(a) A high-pressure water electrolyser. fb) Exploded view of cell (c) A simplrficd flow sheet. (Photograph courtesy CJB Developments Ltd )... 

Compact high-pressure water electrolysers have been utilized to produce oxygen on board nuclear-powered submarines as part of the life-support system the hydrogen by-product, while flammable, is non-toxic and easily handled. Moreover, water and electrical power are the only utilities required. Since 1966, over 1 million running hours have been accumulated in service by such high-pressure electrolysers (Fig. 5.6(a)). 

Alkaline electrolysers are at an industrial stage, especially commercialized for on-site production of ultrapure hydrogen for industrial applications. In general, this hydrogen is needed at low to moderate pressure, and the cost demand is set in comparison to the alternative, which is in general the supply by tube trailers. High purity water is fed to the electrolyzer. State-of-the-art commercial alkaline electrolysers typically operate at HHV systems efficiency of 60-75% [44], Current... 

Marangio F, Santarelli M, Cali M (2009) Theoretical model and experimental analysis of a high pressure PEM water electrolyser for hydrogen production. Int J Hydrogen Energ 34 1143-1158... 

The solid polymer electrolyte cell tends to be slightly larger than corresponding high-pressure cells, and requires a compressor to remove the hydrogen gas. However, it has a number of important advantages compared to other water electrolysers ... 

Electrolytic (coukxnetric) hygrometers The quantity of electricity required to carry out a chemical reaction is measured. The principle is based upon Faraday s law of electrolysis. Water is absorbed on to a thin film of dessicant (e.g. P2O5) and electrolysed. The current required for the electrolysis varies according to the amount of water vapour absorbed. The current depends also upon the flowrate. Capable of high precision. Used in the range 1000 to 3000 ppm of water by volume. Somewhat complicated procedure. Recombination of products to water is necessary after electrolysis. Density, pressure and flowrates have to be maintained precisely. Contamination can poison the cell. It is ideal for binary mixtures but is of limited range. Suitable for on-line operation. 

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