ENEOS builds test unit for a hydrogen carrier production in Australia

Japanese petroleum company ENEOS has built a demonstration plant for methylcyclohexane (MCH) production Australia's Queensland.

PHOTO: Illustration of a supply chain for green hydrogen, toluene and methylcyclohexane (MCH). ENEOS

Hydrogen has a low volumetric energy density. It needs to be stored either in a compressed form at high pressure (350-700 bar) or in a cryogenic form at very low temperatures (−252.8°C) to ensure it does not escape into the atmosphere during transport. However, both processes are very expensive and tend to increase the hydrogen's overall transportation cost.

A new approach to an old problem

Hydrogen producers and suppliers are therefore exploring other methods to transport hydrogen over long distances with minimal boil-off losses. One example of such a technology is the use of liquid organic hydrogen carriers (LOHCs).

In LOHC-based technology, hydrogen is chemically bonded to stable liquid organic carriers, which are derivatives of oil that react reversibly with hydrogen. It can be stored without being compressed and requires little to no changes in storage infrastructure, which can make it a cost-effective alternative for long-range transportation of hydrogen.

MCH is a LOHC made by reacting hydrogen with toluene. Chemically, it is a saturated hydrocarbon and is commonly used as a solvent.

According to ENEOS, “MCH contains over 500 times more hydrogen per volume than hydrogen gas, so it can carry hydrogen more efficiently. In addition, MCH is a liquid with petroleum-like characteristics, so it can be used in existing petroleum infrastructure.”

ENEOS has developed a method called "electrochemical synthesis of organic hydride" which can produce MCH from water and toluene without using pure hydrogen.

The electrochemical reaction will be powered by renewable energy to produce "green" MCH, says the company. Green hydrogen can then be extracted from green MCH after it has been shipped to receiving destinations in Japan and elsewhere.

As part of its eight-month demonstration period this year, ENEOS will produce "MCH equivalent to approximately 2 to 3 mt of hydrogen for 400 to 600 fuel cell vehicles" and transport it to Japan for green hydrogen extraction.

Growing demand for LOHCs

Another Japanese company, Mitsui O.S.K Lines (MOL), is also looking at MCH to store green hydrogen on its "mobile hydrogen production plant" vessel concept.

More broadly, LOHCs are becoming increasingly popular in Europe as it strives to boost its hydrogen economy.

Dutch storage terminal company Vopak and German Hydrogenious LOHC Technologies intend to develop LOHC-based hydrogen supply chains within existing infrastructure. A consortium led by the Net Zero Technology Centre and the Port of Rotterdam is creating a "hydrogen highway" between Scotland and Rotterdam based on LOHC technology.

By Konica Bhatt

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