Ammonia slip significantly cut by exhaust gas after-treatment system, reports KR

A South Korean government-backed tripartite co-operation has developed an exhaust gas after-treatment system for megawatt-scale ammonia-fuelled engines that significantly reduces NOx emissions, NH3 emissions and ammonia slip.

The results were announced by the class society Korean Register (KR), which is leading the development of the exhaust gas after-treatment system. Others involved in the government-funded project are EcoPro HN and HD Korea Shipbuilding & Offshore Engineering.

Land-based demonstrations under the ‘Comprehensive Management Technology Development for Ship Greenhouse Gas Emissions’ project showed a 95% reduction in NOx emissions, a 99.7% reduction in ammonia emissions, and ammonia slip reduction from an initial level of 10,000 ppm to 30 ppm.

Such results are encouraging because of the highly toxic nature of ammonia, which requires not only special aftertreatment, but also handling during bunkering and ammonia engine operation and maintenance. Additionally, N2O, part of NOx emissions, is a powerful greenhouse gas that has a global warming potential 273-298 times that of CO2 on a 100-year timescale. Applying a microwave-based catalyst heating method enabled rapid and efficient catalyst activation, significantly enhancing exhaust gas purification performance, according to KR.

Several ammonia dual-fuel-propelled vessels will enter service in 2026, as shipowners test the fuel’s effectiveness in reducing CO2 and greenhouse gas emissions.

KR executive vice president, Kim Daeheon, said, “For the commercialisation of ammonia-fuelled vessels, securing exhaust gas after-treatment technology is just as important as fuel technology itself. Through this demonstration, we have validated the effectiveness of the jointly developed system. Going forward, we plan to expand its application to various dual-fuel engines and actively support the transition toward carbon-free shipping.”

The project is supported by the Ministry of Oceans and Fisheries and the Korea Institute of Marine Science & Technology Promotion.
The newly developed system is South Korea’s first microwave catalyst-heating exhaust gas after-treatment system applied to MW-class ammonia engine exhaust.

The prototype underwent extended operational tests at the KR Green Ship Test & Certification Center, where its performance was verified.