Electrochemical hydrogen compression and purification versus competing technologies: Part I. Pros and cons

Abstract

It is undisputed that hydrogen will play a great role in our future energetic mix, because it enables the storage of renewable electricity (power-to-H2) and the reversible conversion into electricity in fuel cell, not to speak of its wide use in the (petro)chemical industry. Whereas in these applications, pure hydrogen is required, today's hydrogen production is still largely based on fossil fuels and can therefore not be considered pure. Therefore, purification of hydrogen is mandatory, at a large scale. In addition, hydrogen being the lightest gas, its volumetric energy content is well-below its competing fuels, unless it is compressed at high pressures (typically 70 MPa), making compression unavoidable as well. This contribution will detail the means available today for both purification and for compression of hydrogen. It will show that among the available technologies, the electrochemical hydrogen compressor (EHC), which also enables hydrogen purification, has numerous advantages compared to the classical technologies currently used at the industrial scale. EHC has their thermodynamic and operational advantages, but also their ease of use. However, the deployment of EHCs will be viable only if they reach sufficient performances, which implies some specifications that their base materials should stick to. The present contribution will detail these specifications.