New liquid hydrogen carrier in combination with residual heat offers opportunities for safe and efficient hydrogen storage
31 August 2022
Hydrogen is in the news almost every day. Green hydrogen – made from water and renewable electricity – is a promising fuel for various applications in industry, chemistry, heavier mobility and in the broad sense for energy storage and transport. The biggest challenge at the moment is the safe use of hydrogen and its transport. It is currently still necessary to compress or liquefy hydrogen to high pressures, so that you can actually transport large quantities. Koninklijke van Twist (KvT), Voyex and Fieldlab Industrial Electrification (FLIE) have jointly conducted research into an alternative way of making hydrogen storage safe, simple and efficient, by using a liquid hydrogen carrier. Voyex is developing this hydrogen carrier, also called LOHC-Liquid Organic Hydrogen Carrier technology . Basically it means that a specific liquid is synthesized, that you bind hydrogen gas to that liquid and then extract it where you need it. The liquid is used in a circular manner to be charged and discharged with hydrogen each time.
Koninklijke van Twist has built a 100% hydrogen generator and sees the potential benefits of LOHC to supply the generator with hydrogen. The liquid is safer than diesel and can store a lot of hydrogen. 59 kilograms of hydrogen per tonne can be stored. Since it is a liquid, it can be integrated into the supply chain in the same way as we are used to now. A relatively small system is also required to extract the hydrogen, making it easy to fit in or close to the ultimate hydrogen user. Heat is needed to extract the hydrogen from the liquid, and that is precisely what the KvT hydrogen generator produces as ‘residual current’ in addition to electricity. The feasibility study was mainly aimed at determining whether sufficient heat is available and what an integrated system would look like.
The feasibility study has shown that almost all the heat is available to be able to extract the hydrogen from the carrier. Only 4% of the hydrogen would be ‘sacrificed’ for additional heat. In addition, it has been shown that the system remains compact enough to be easily installed next to the KvT generator. Given the high energy density of the liquid carrier, energy can be provided for several days in standard storage tanks. For example, with a ten cubic meters of storage, you can store 20 megawatt hours of energetic energy. The technical attractiveness of the concept has thus become clearly visible and provides all the necessary input to investigate the further (business) case for a first prototype.
These insights have made it clear how LOHC fits in with combustion engine technology such as the KvT generator. Now it is necessary to develop a system that supplies hydrogen to a generator in practice. It is of great importance to realize heat integration in order to reinforce the study that has been carried out. In the future, the LOHC technology may be scaled up further, eg via a pilot factory, in collaboration with FLIE.