The first Wärtsilä two-stroke engine with a high pressure SCR (Selective Catalytic Reduction) system manufactured in China has been introduced. This is the first SCR system that complies with the IMO's Tier III regulations for NOx emissions.
The system is fitted to a 5-cylinder Wärtsilä RT-flex58T-D 2-stroke, low speed engine produced at the Hudong Heavy Machinery Co Ltd (HHM) facilities. The SCR reactor was also manufactured by HHM.
Multi-Purpose Vessel
The engine with SCR is to be installed in a new 22,000 dwt multi-purpose vessel currently under construction at the Ouhua shipyard on behalf of China Navigation Co (CNCo). The ship, which is scheduled for delivery in the second quarter of this year, has been designed to allow sufficient space for the fitting of the SCR.
SCR System
The SCR system for this application has been jointly developed by HHM and Winterthur Gas & Diesel (WinGD), the joint venture company of Wärtsilä and China State Shipbuilding Company (CSSC), using a basic design concept from Wärtsilä which has been adapted to suit the particular requirements of the engine and ship. The SCR system injects a solution of urea into the exhaust gas flow to react with and eliminate the NOx emissions.
It is a high pressure process because the reactor is located between the engine exhaust valves and the turbocharger turbine inlet. This provides the most compact and efficient system without compromising engine performance or impacting fuel consumption.
Picture: High-pressure SCR system jointly developed by Winterthur Gas & Diesel Ltd and Hudong Heavy Machinery Co Ltd. The cylindrical SCR reactor unit is located in the exhaust duct from the engine cylinders to the turbocharger turbine inlet (courtesy of Winterthur Gas & Diesel Ltd).
