Catalytic Reduction Controls
The Institute of Clean Air Cos. (ICAC), the national association of stationary source air pollution control companies, has released a revised version of its white paper, Selective Catalytic Reduction (SCR) Controls to Abate NOx Emissions. The paper, written by ICAC?s SCR Committee, provides information on the capabilities, limitations, applications and costs of SCR.
In the SCR process, ammonia is injected into exhaust gases containing nitrogen oxides. A catalyst promotes the reaction of ammonia with NOx to produce harmless nitrogen gas and water vapor. Control levels of greater than 90 percent are achieved in many cases, with unreacted ammonia (ammonia slip) emissions typically below 10 ppm, and often below 2 ppm. In some cases, systems providing lower levels of control have been installed to meet less stringent permit limits.
SCR is being used to control NOx emissions from more than 200 units in the United States, including utility and industrial boiler, stationary internal combustion engines, gas turbines, process heaters, annealing furnaces and chemical plants, according to Jeffrey C. Smith, ICAC executive director.
The 31-page SCR white paper is available from ICAC. Call Judi Stuart at (202) 457-0911 for information.