A collaboration between CB&I and Shell, with close support from DNV, has led to the Approval in Principle (AiP) of a large-scale, liquid hydrogen (LH2) cargo containment system. This could pave the way for an expansion of global hydrogen supply chains in the future.
Hydrogen Transportation
Hydrogen is free from carbon and thus viewed as a potentially key contributor to global emissions reductions, especially when created through electrolysis. However, its transportation presents several complications. Whilst some regions could import hydrogen via pipeline, this is not possible over longer distances, such as from Asia to Europe, and shipping solutions are required.
Shipping hydrogen in liquid form is regarded as more practical than gas because of its higher energy density. However, LH2 shipping presents some extra challenges, particularly related to safe storage.
“To liquefy hydrogen, it must be cooled to minus-253 degrees Celsius,” says Tom Klungseth Østvold, Principal Engineer, Structures at DNV Maritime Advisory. “Once this is done, the liquefied hydrogen needs to be stored in tanks with the highest standards in vacuum insulation. Exposing the hydrogen to normal gases will lead to significant impairment as well as many safety hazards.”
Drawing From Experience
Utilizing technological expertise from the global leader in land-based liquid hydrogen storage can help shipping to achieve higher standards in liquid hydrogen transportation.
“CB&I’s LH2 cargo containment system for LH2 carriers is based on our technology for large-scale onshore LH2 storage,” explains David Creech, Director, R&D at CB&I. “The most reliable design meeting these requirements is a vacuum-insulated double-wall sphere, which provides boiloff rates of less than 0.05% per day, as demonstrated in tests of CB&I’s tanks by NASA. By adapting this technology for shipping, we can provide the market with a proven design backed by over 60 years of operational history.”
Overcoming The Gap
Taking this initial design through to AiP has also required careful navigation of maritime regulations and safety codes, including class rules, the International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code) and the IMO’s Interim Recommendations for Carriage of Liquefied Hydrogen in Bulk, Resolution MSC.420(97). This has been a challenging proposition for a relatively novel maritime technology.
“The immaturity of rules and regulations for LH2 cargo containment systems in maritime transport was a major challenge. This led to the decisions being made at the start of the project about which sections of the IMO’s IGC Code should be applied, despite the code not currently including LH2 as cargo,” says Cocks.
Design Adaptation
Close collaboration with DNV has led to some incremental changes to the original design, resulting in a concept that is robust and fully fit for maritime transportation.
“It was a smooth process with good dialogue on all sides,” says Østvold. “We covered a lot of areas, probably in more detail than is strictly necessary for an AiP, but this resulted in a final design that’s safe and has very few uncertainties.”
Achieving AiP a Key Milestone
Receiving an AiP from DNV has been a key milestone in the development of the LH2 carrier concept, paving the way for further development of hydrogen supply chains.
“The awarding of an AiP from DNV resulted from a lot of hard work and collaboration between companies working at the forefront of innovation in this sector,” says Cocks. “To support the role of liquid hydrogen in the energy transition it’s critical that its potential as a viable energy carrier is demonstrated with urgency. Achieving this AiP was a significant step in the right direction.”
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Source: DNV
