Raporty IChTJ. Seria B nr 1/2025
(Metody emisji gazów cieplarnianych ze spalania paliw kopalnych z wykorzystaniem technologii radiacyjnych, w szczególności w silnikach wysokoprężnych instalowanych w jednostkach transportu morskiego)
Andrzej Pawelec, Andrzej G. Chmielewski
The greenhouse gases (GHG) emissions are of special interest nowadays and this also covers emission from shipping sector. As over 96% of global shipping sector is powered using heavy duty diesel engines, the research on various methods of greenhouse gases emissions mitigation for marine application are intensively performed.
The International Maritime Organization (IMO) has elaborated the strategy leading to reduction of greenhouse gases emissions from ships. According to the 2023 IMO Strategy on Reduction of GHG Emissions from Ships, carbon dioxide (CO2) emissions from international shipping shall be reduced by at least 40% by 2030, compared to 2008, and net-zero GHG emissions shall be reached by or around 2050.
The most common option to meet the IMO greenhouse gases emission goals, discussed nowadays, is fuel switching for low-carbon emission fuels such as biodiesel, liquefied natural gas (LNG), ammonia, methanol and others. The other approach for carbon dioxide emission mitigation is application of post-combustion carbon capture technologies. These technologies were first developed and commercialized for their onshore applications; therefore, they are considered a ready to deploy and possible long-term solution option for CO2 emission reduction from the marine sector.
There are known several methods of CO2 capture, such as absorption, adsorption, chemical looping combustion, membrane separation, hydrate-based separation and cryogenic separation; however, not every one of them may be applied in marine conditions. Among them there are four main technologies considered for carbon capture applications at shipping industry: chemical absorption, adsorption, membrane separation and cryogenic separation. Although there are carried out intensive research on application of these methods in marine industry, at present only few demonstrational attempts were achieved. Although the post-combustion carbon capture methods are regarded as a perspective solution of marine carbon dioxide emission, there is still a lot of issues to be solved.
Apart from the known CO2 emission mitigation technologies, a new one – electron beam induced carbon dioxide mitigation process was proposed. The process is based on the reaction of oxalates creation from CO2 under electron beam irradiation in the presence of formates. The technology involves a two-step process, where in the first step, acidic pollutants such as sulfur dioxide (SO2) and nitrogen oxides (NOx) are removed in the hybrid electron beam flue gas treatment process, while in the second step, carbon dioxide is removed by irradiation in the presence of formates. The condensed effluents containing absorbed acidic pollutants or oxalates shall be stored onboard and unloaded at harbor, regarding that sodium and potassium oxalates are the commercial products and may be directed for further applications. The possible modification of the process may lead to the formation of sodium salt in ionic form which may be discharged to the sea.
The process is under development; however, its application for marine conditions is possible.