ClassNK grants Daihatsu Diesel AIP on LPG Reformer
Classification Society ClassNK has granted an Approval in Principle (AIP) to Daihatsu Diesel and Osaka Gas for their joint project with an LPG Reformer for marine engines. This was the first AIP granted in Japan for such equipment.
The LPG Reformer is designed to convert LPG into synthetic methane gas equivalent to the kind found in LNG. Due to being mainly composed of propane and butane, LPG has a low methane number and will self-ignite outside the envelope of the normal combustion front. This causes the engine to knock making it difficult to use as a fuel for lean burn gas engines and dual fuel engines. In contrast, by converting LPG into synthetic methane gas with the LPG Reformer prior to fuelling the engine, the risks of knocking can be restrained, resulting in equivalent operational performance observed when using LNG. Additionally, by using LPG as fuel, the emission of environmentally harmful substances like SOx and NOx can be significantly reduced compared to when using conventional heavy oil fuels, allowing for compliance to the 2020 IMO SOx regulation and more by using marine engines themselves.
When using LPG as fuel, the International Code of Safety for Ships using Gases or other Low-flashpoint Fuels (IGF code) applies. The current IGF code, however, does not address specific regulations for alternative fuels other than LNG. For this reason, ClassNK released Guidelines for Ships Using Low-Flashpoint Fuels (Methyl / Ethyl Alcohol / LPG) in June 2019 which outline safety requirements for other viable alternative fuels besides LNG. The recently issued AIP to Osaka Gas is also in line with these guidelines.
Hiroaki Heima of Daihatsu Diesel presented a paper on its LPG reformer project with Osaka Gas at the CIMAC Cascades in Kobe in November 2018.