Molecule profile: LOHC
Chemical hydrogen storage – what is that actually supposed to be? The question is of course completely justified, because the subject of hydrogen is highly complex, although H2 is the first and, in terms of its molecular structure, one of the simplest elements of all.
Roughly speaking, there are two methods of storing hydrogen: physical and chemical. Physical means that hydrogen is either compressed under high pressure or cooled to -253 degrees Celsius. In both cases, the volume is reduced. Chemical means that hydrogen is incorporated into another molecule. This is the case with liquid organic hydrogen carriers (LOHC), which, figuratively speaking, function like a deposit bottle for hydrogen. The carrier is loaded with hydrogen and can thus be stored, stored and transported and then released from the carrier again. The discharged carrier is then ready to be reloaded. Such chemical storage methods are the focus of basic research at the Institute for Sustainable Hydrogen Economy (INW) at Forschungszentrum Jülich, which forms the core of our cluster.
The aim of all physical and chemical storage methods is to improve the manageability of hydrogen, for example to make it easier to transport. Each method is used to compress molecular hydrogen, which in its pure form under ambient conditions has a large volume that is more difficult to handle. Each method has its strengths, which are to be exploited for different applications. Hydrogen physically stored under pressure is used in mobility, for example, because trucks and buses are refueled with hydrogen compressed to 350 bar and cars with 700 bar.
As mentioned above, the INW focuses on chemical storage methods, among other things, because the energy required for storage is usually lower than with physical methods. But chemical storage also has its challenges. In this series, we present the chemical storage systems that our researchers are working on in a series of profiles. Finally, we present LOHC.
You can find an example of how LOHC is used in practice here in our Multi-SOFC demonstration project at Erkelenz Hospital.
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