Feadship has created a new technology to reduce nitrogen oxide (NOx) emissions from diesel propulsion engines on yachts.
Selective catalytic reduction (SCR) systems currently in use to bring engines into compliance with IMO tier III and EPA IV regulations only work when the exhaust temperature around the catalyst is at a certain level, which requires high speed, Feadship noted in a press release.
The systems also require yachts to carry a large volume of diesel exhaust fluid in holding tanks.
To address these issues, the company’s engineers partnered with the gas treatment department of the Netherlands Organization for Applied Scientific Research (TNO) to develop Oxywash, based on an idea from Roderick de Vries, technical director at Feadship Koninklijke De Vries Scheepsbouw.
According to Feadship, Oxywash systems remove NOx irrespective of engine temperature, take up less space, and are more environmentally friendly than standard SCR solutions. Oxywash works by making NOx water-soluble, then transferring it directly into seawater, where it is transformed into nitrite and nitrate.
When exhaust gas temperature is high, the reaction takes place via a catalyst; when the temperature is lower, ozone is instead injected into the gas to make it water-soluble. The ozone required is generated on board from the air, eliminating the need to keep chemicals on board, the company stated.
The technology is undergoing large-scale prototype testing, and the systems are expected to be ready for fitting on yachts soon, according to Feadship.