Maritime majors complete NH3 co-firing test using 4-stroke NH3-fueled engine

A maritime consortium involving NYK Line, IHI Power Systems, Nihon Shipyard, Japan Engine Corporation and Nippon Kaiji Kyokai (ClassNK) has announced that the world’s first four-stroke ammonia-fueled (NH3-fueled) engine has completed a land-based test for the stable combustion of fuel ammonia having an 80% co-firing ratio as part of a demonstration project for the commercialisation of vessels equipped with a domestically produced ammonia-fueled engine.

The initiative concerning the development of vessels equipped with a domestically produced ammonia-fueled engine was initiated in October 2021 by NYK, Japan Engine Corporation, IHI Power Systems and Nihon Shipyard as part of the Green Innovation Fund Project of the New Energy and Industrial Technology Development Organisation (NEDO).

In April 2023, IHI Power Systems commenced operational tests at its Ota plant (Gunma Prefecture) on a 280 mm bore four-stroke ammonia-fueled marine engine for the main engine of coastal vessels (i.e., ammonia-fueled tugboats – A-Tug).

ClassNK explained that ammonia is expected to be a next-generation fuel that contributes to combating global warming, but it is a difficult substance to handle due to its toxicity. However, the company noted: “This time, while thoroughly ensuring safety, a test increased the mixing ratio of fuel ammonia within the engine to 80%, and tests were conducted on the exhaust gas after treatment devices and fuel supply systems, etc., and the stable integrated operation of these systems was successfully achieved for the first time.”

Tests also confirmed that emissions of dinitrogen monoxide (N2O) and unburnt ammonia were virtually zero and there was no ammonia leakage from all demonstration equipment during operation and after shutdown, the company added.

To note, ClassNK said that prior to the test, a demonstration equipment inspection and technical review meeting were held on 11 April at IHI Power Systems’ Ota plant. Keihin Dock, which is responsible for the conversion of the A-Tug, and Shin-Nippon Kaiyosha, which is responsible for the operation and management of the vessel, also participated in the inspection.

In regard to future plans, ClassNK informed that after further land-based testing, the engine will be installed on A-Tug, which will be completed in June 2024. Furthermore, efforts are expected to be made to develop a 250 mm bore engine for the auxiliary engine of an oceangoing vessel. According to ClassNK, that auxiliary engine will be installed on an ammonia-fueled ammonia gas carrier (AFAGC), scheduled for delivery in October 2026 under joint development by NYK, Nihon Shipyard, Japan Engine, IHI Power Systems, and ClassNK.

“Starting with the success of this demonstration test, the consortium will continue to work together to strengthen the international competitiveness of the Japan maritime cluster, with the aim of building the world’s first ammonia-fueled ships and achieving safe navigation, including by contributing to the development of international rules,” ClassNK said.