Catalytic Control of NO_x, CO, and NMHC Emissions From Stationary Diesel and Dual-Fuel Engines

Selective Catalytic Reduction (SCR) and oxidation catalyst technology have been applied to a stationary diesel and dual-fuel (natural gas and #2 diesel) engine for catalytic control of nitrogen oxides (NO_x), carbon monoxide (CO), and nonmethane hydrocarbon (NMHC) emissions. At rated conditions, NO_x emissions have been effectively reduced by up to 90 percent, with little loss of SCR catalyst performance after 850 hours of operation. Using adequate control of the ammonia (NH₃) feed, the SCR system was capable of maintaining NH₃ slip to 10 ppm or less. CO and NMHC were reduced by 93 and 85 percent, respectively. Little soot was observed on the surface of the catalyst due to the use of a catalyst system that minimizes the buildup of heavy hydrocarbons on the catalyst surface. In addition, the catalyst structure effectively resisted the buildup of sulfur compounds that could cause premature deactivation of the catalyst.