AALSMEER _ Working with Dutch researchers, Feadship reports a breakthrough technology – called Oxywash – which, it says, stops superyachts from releasing nitrogen-oxide emission into atmosphere. The first systems will soon appear on Feadship yachts.
Oxywash systems are compacter than selective catalytic reduction (SCR) ones which can be burdened by tons of diesel exhaust fluid (DEF) and work only at high speeds, a rare occurrence during a superyacht voyage.
Based on an idea by Roderick de Vries, technical director at Feadship Koninklijke De Vries Scheepsbouw, Oxywash systems remove NOx regardless of engine temperature whereas SCR technology only works when the exhaust temperature around the catalyst is at a particular level. The Oxywash technology works in any situation making it environmentally friendlier, Feadship says in a statement.
All this matters because compliance with the NOx regulations of the International Maritime Organization are a handful as diesel engines cannot be modified to deliver the required emissions cut. Feadship says it developed a better system in concert with engineers at the gas treatment department of the Dutch applied sciences research institute TNO.
The principle behind Oxywash is to first make NOx water-soluble, then immerse it into seawater. When the exhaust gas temperature is high, the reaction takes place via a catalyst. If it is lower, ozone is injected into the gas to make it water-soluble. The ozone comes from the outside air so no need for bulky chemicals on board.
The water-soluble NOx goes into the seawater, not into the atmosphere, and is transformed into nitrite and nitrate, substances naturally present in seawater. Nitrites and nitrates are essential for aquatic marine plants and animals.
The Oxywash technology has been tested at TNO’s lab in Delft. A large-scale test program, now underway, will explore additional technology features such as Oxywash’s capacity to remove particulate material.