New test system aims to reduce methane slip from LNG ship engines
Japanese researchers and industry partners are testing a newly developed catalyst aboard an operational LNG bunkering vessel, aiming to reduce methane slip—a long-standing environmental drawback of LNG as a marine fuel.
This is according to The Maritime Executive.
In collaboration with Daihatsu Infinearth Mfg. Co., Mitsubishi Heavy Industries Marine Machinery & Equipment has developed a so-called methane oxidation catalyst, which has demonstrated a degradation effect of over 70 percent in land-based testing facilities.
The system is now installed on board the bunkering vessel KEYS Azalea, delivered in 2024 and operating with LNG supplies in southern Japan.
The catalyst works by converting methane (CH₄) in the engine’s exhaust gas into carbon dioxide (CO₂) and water vapor (H₂O) through a chemical reaction with oxygen. According to the companies behind the project, the goal is to reduce what is known as methane slip—unburned methane emissions—which has faced criticism from environmental organizations, as methane is a far more potent greenhouse gas than CO₂.
The demonstration test will continue for at least a year and forms part of Mitsubishi Heavy Industries’ broader energy transition strategy and the maritime sector’s green transformation.
According to the company, the project exemplifies how the industry is working to improve LNG’s environmental profile—both in the short term and in terms of the fuel’s long-term viability as an alternative to oil. The technology is initially aimed at the newest generation of LNG engines.
