LOHC Technologie - A Overview

The so-called Marlotherm is used as a Liquid Organic Hydrogen Carrier (LOHC), i.e. a liquid carrier medium for hydrogen. This oil-like liquid has been used as a heat transfer oil in a wide variety of applications and industries for years. Its ability to chemically bind hydrogen was discovered some time ago. By chemically binding the hydrogen, it can also be stored under normal conditions, contrary to current practice.

This makes hydrogen handling not only safer, but also cheaper. With LOHC, the volatile hydrogen gas no longer needs to be cooled or compressed in a costly and energy-intensive manner in order to enable economical transport.

One m³ LOHC enables the safe storage of 57 kg H2.

What can LOHC do?

With LOHC we have the possibility to compensate for temporal fluctuations and also local discrepancies between the generation and the demand of energy. This makes hydrogen easy to transport. For example, from northern Germany, where hydrogen can be produced using wind energy, to the south, where hydrogen can help reduce CO₂ emissions in refineries.

Use at petrol stations or in ship drives is just as conceivable as use in the glass and cement industries. All areas in which hydrogen can be used can and will also benefit from LOHC as hydrogen storage.

How does LOHC work?

With pressures between 30 – 50 bar and catalysts specially developed for this application, the LOHC can be hydrogenated, i.e. hydrogen can be chemically bound. The resulting hydrogenated LOHC + can then be handled using the known infrastructure for fuels such as gasoline and diesel. The hydrogenation process is exothermic. The waste heat developed in this way can be used in other processes and thus increases the overall system efficiency.

If the hydrogen is needed again, for example in chemical process plants, the steel industry or to supply fuel cells in order to use electrical energy, it can be extracted again from the LOHC +.

In order to dehydrate the LOHC +, i.e. to release the hydrogen from the liquid again, the LOHC + passes through a dehydrogenation reactor, which contains the catalyst required for this process. In contrast to hydrogenation, dehydrogenation is an endothermic reaction. The necessary energy must therefore be added and can, for example, be made available within the system by using the hydrogen itself or provided by other, external heat sources.

The dehydrogenated LOHC- can now be returned to the location of the hydrogenation and reloaded with hydrogen. The cycle is closed. The LOHC itself is not consumed, but reused many times over. The service life is also increased by the possibility of purification as soon as this becomes necessary after various (de) hydrogenation cycles.

What is LOHC?

LOHC is a heat-resistant oil with a capacity of 57 kg hydrogen per 1 m³. Hydrogen is chemically bound to and released from the LOHC in a chemical reaction on a catalyst.