Shell, Alfa Laval to develop GCU for liquefied hydrogen carriers

Shell International Trading and Shipping Company Limited has signed a memorandum of understanding (MOU) with Swedish sustainable solutions provider Alfa Laval regarding the development of a new gas combustion unit (GCU) for use on liquid hydrogen carriers.

Credit: Alfa Laval

Under the MOU, Alfa Laval will develop a system to safely combust hydrogen boil-off gas (BOG) from a vessel’s storage tank, as part of a new liquid hydrogen carrier.

Alfa Laval will design and engineer the new GCU for hydrogen with the aim of receiving an approval in principle (AIP) from an IACS classification society. Once the AIP is achieved, a GCU prototype will be built for testing and type approval.

The design of the new GCU system for hydrogen will be based on the existing Alfa Laval’s GCU for liquefied natural gas (LNG). More than 200 of these units have been installed in just over a decade, and an additional 100 units have been ordered during 2022, according to the company.

However, the challenges in hydrogen combustion are significantly greater than those involved with LNG.

This is why the adoption of hydrogen as marine fuel for deep sea-going vessels seems to be lagging behind its counterparts such as methanol and ammonia.

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Hydrogen is an attractive fuel for internal combustion engines and its combustion produces no greenhouse gas emissions. However, hydrogen needs to be compressed (700 bar) or liquified (-253 °C), which requires substantial ingenuity from the engineering side so as to enable a vessel to store the chemical element safely at such low temperatures while keeping the structural integrity of the tanks and the entire vessel intact.

“With its boiling point of -253°C, hydrogen is expected to have a higher boil-off rate than methane, which will make having a GCU or similar means of BOG handling crucial on hydrogen carriers,” commented David Jung, Business Development Manager, Alfa Laval.

“In addition, hydrogen is light, highly flammable and easy ignitable. Safety will be paramount when transporting it on board, so there are critical safety considerations when designing the GCU system.”

In this case, because the venting of cargo is restricted, a GCU offers a means of controlling tank pressure/temperature when the BOG poses safety risks beyond the tank’s design conditions.

“Renewable hydrogen will likely be a key fuel in tomorrow’s decarbonization mix, but accessibility will determine its impact,” said Carl Henrickson, General Manager of Shipping Technology, Shell.

“By enabling safe ocean transport of liquid hydrogen, we can help speed up the global transition to clean energy and Shell’s target to become a net-zero emissions energy business by 2050.”

Shell has recently joined forces with ENGIE, Vopak and Anthony Veder to study the feasibility of producing, liquifying and transporting hydrogen from Portugal to the Netherlands.

The consortium envisions hydrogen being produced by electrolysis from renewable power in the industrial zone of the Sines port. Then the hydrogen is liquified and shipped via a liquid hydrogen carrier to the Port of Rotterdam for distribution and sale.

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Building more certainty for customers of liquid hydrogen is needed. Policy instruments that cover cost increases for end-users can be an effective means to achieve this.

Such instruments are vital to increase the scale and reduce the cost of liquid hydrogen production and have the power to drive the infrastructure development along the full supply chain.