Shell International Trading and Shipping Company Limited has signed a memorandum of understanding (MoU) with Alfa Laval regarding the development of a new Gas Combustion Unit (GCU) for use on liquid hydrogen carriers.
By paving the way for the safe transport of hydrogen by sea, the project is considered to be an important step on the path to global decarbonisation. 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. 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.
Carl Henrickson, GM Shipping Technology, Shell said: “Renewable hydrogen will likely be a key fuel in tomorrow’s decarbonisation mix, but accessibility will determine its impact. 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. Alfa Laval shares our ambition and is our choice of partner.”
David Jung, Business Development Manager, Alfa Laval, added: “We are proud to support Shell in developing a marine infrastructure for hydrogen. Global hydrogen demand is expected to grow many times larger than it is today, and liquid hydrogen carriers at sea will be a vital link in the world’s decarbonised fuel chain.”
From experience in gas combustion on LNG carriers, Alfa Laval believes it has the insights and technology that will act as a springboard. The design of the new GCU system for hydrogen will be based on the existing Alfa Laval GCU for 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. The challenges in hydrogen combustion, however, are significantly greater than those involved with LNG.
Jung explained: “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. 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.”
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.