Mitsubishi Heavy Industries Marine Machinery & Equipment Co., Ltd. (MHI-MME) has started testing a methane oxidation catalyst system for LNG-powered ships.
As explained, the methane oxidation system is being developed with Daihatsu Infinearth Mfg. Co., Ltd. and aims to reduce methane emissions from ship engines.
The trial, which began in May, is being carried out on the LNG bunkering vessel KEYS Azalea. The catalyst system works by reducing unburned methane in exhaust gases, which is important because methane has a strong greenhouse effect.
Do you know what a methane slip is?
Equipment that uses natural gas as a fuel is generally designed to have at least 98% combustion efficiency – which means at least 98% of the gas to be burned. This also means that the other 2% of methane is released as unburned gas. This is known as methane slip.
In simpler terms, methane slip is the unburned fuel that is not fully combusted in ships’ engines. Although methane slip accounts for a generally a small percentage of the fuel used, in operations that use a significant amount of energy, methane slip can be a major source of emissions.
Furthermore, the system, has already shown a 70% reduction in methane in initial tests and the demonstration will continue to run for a year to further assess its effectiveness.
According to DNV, methane slip, as based on standard factors, can account for up to 24% of GHG emissions from an LNG-fuelled vessel. Even though the total amount of methane slip might initially seem minor, it significantly impacts reported GHG emissions.
