Electrolysis: the key to new value chains
Due to the energy revolution and the increasing share of renewable energies with volatile availability, the coupling of the energy and the chemical sector is gaining new momentum - and electrolysis is gaining in importance. After all, electrolysis is the key to many cutting-edge processes and the decisive interface between the electricity and chemicals sectors.
The ideabehind "sector coupling"is to use electricity for the production of fuels or chemicals. Electrolysis plays a key role in almost all processes. Water electrolysis is a central part of this process. The hydrogen obtained by splitting water can either be used as an energy carrier, for example for fuel cells, or fed into the production of chemicals. A large number of industrial projects reflects on the importance of this technology: New construction projects are reported on almost daily, from the local hydrogen cogeneration plant to megaprojects such as the planned 10 and 20 MW projects announced by AkzoNobel and Shell at the beginning of 2018. At the same time, the development of electrolysis cells is progressing: new electrode materials or developments such as PEM electrolysis cells ensure that the processes become increasingly efficient and, depending on the further use of hydrogen, also economically competitive. However, in a report to the BMWi in April 2018, the Wuppertal Institute and Fraunhofer ISI point out that the electrolysers currently available are not series products and that a necessary scale-up must take place quickly. This would also create opportunities for the export market.
And for some time now, attention has no longer been focused solely on hydrogen production. The co-electrolysis of water and carbon dioxide into synthesis gas is also currently being investigated in more detail. In the Rheticus research project, Siemens and Evonik are working on a process for converting carbon dioxide into butanol and hexanol with the aid of regenerative electricity and microorganisms. Siemens is supplying the electrolysis technology and is developing the first gas-gas electrolyzer on an industrial scale.
Even though the focus is on the production of valuable chemicals, the process also has a second aspect that makes it particularly interesting for coupling to renewable energy sources: It can be adjusted up and down within a certain range and could therefore use more or less energy per unit of time, depending on the amount of electricity available.
This applies only to a very limited extent to the classic electrolysis process, chlor-alkali electrolysis. Because the chlorine formed is the starting point for many other chemicals, and the production quantities cannot be reduced without further ado. But even in this supposedly long-developed process, there is still potential for innovation: for example, the use of oxygen depolarized cathodes has made it possible to reduce Covestro's energy consumption for chlorine production by up to 30 %.
At the PRAXISforum Electrolysis in Industry on 22 and 23 November 2018 in the DECHEMA House in Frankfurt, users and suppliers will be discussing which electrolysis applications are currently on the agenda and how their potential can be exploited even better. Registration for exhibitors and participants is open; more at www.dechema.de/electrolysis
32a/2018
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