An Approval in Principle (AiP) has been granted by ClassNK for a dual-fuel generator engine using hydrogen gas as fuel and related machinery systems and arrangements for a 160,000m3 liquefied hydrogen carrier vessel designed by Kawasaki Heavy Industries (KHI). The AiP is ClassNK’s first for a dual-fuel generator engine using hydrogen gas as fuel.
With the use of hydrogen increasing as a clean energy source, ClassNK has established new standards and certifications to cover its use within the maritime industry as a fuel and also for maritime transportation.
To date, ClassNK has issued previous AiPs for other systems on board the liquefied hydrogen carrier which includes the dual-fuel main boilers that use hydrogen boil-off gas as fuel, a Cargo Containment System (CCS) and a Cargo Handling System (CHS).
During the most recent examination of the vessel’s systems, ClassNK conducted a design review of the dual-fuel generator engines which use hydrogen gas as a fuel, in addition to reviewing other related machinery systems and arrangements based on the classification society’s Part N of Rules for the Survey and Construction of Steel Ships incorporating the International Gas Carrier Code, and its Guidelines for Liquefied Hydrogen Carriers incorporating the International Maritime Organization’s interim recommendations for Carriage of Liquefied Hydrogen in Bulk.
The dual-fuel generator engine from KHI is said to be capable of switching between hydrogen and low-sulfur fuel oil flexibly. Additionally, when hydrogen fuel is selected, boil-off gas which is naturally evaporated from the vessel’s liquefied hydrogen cargo tanks is used as the main fuel at a calorie-based mixed ratio of 95% or higher to generate and supply electricity on board.