Performance, Maintenance and Environmental Benefits of An Integral SCR

Selective Catalytic Reduction (SCR) involves injecting a NOx reducing chemical, such as aqueous ammonia, into the an exhaust stream in the presence of a catalyst within a specific temperature window of approximately 650°F to 1100°F. To reduce NOx emissions from an ethylene cracker, Chevron Phillips Chemical Company LP retrofitted new convection sections on 13 existing ethylene furnaces, which incorporated both integral steam superheating coils and integral SCR's for NOx removal. This paper expands on the information presented at the 2008 AICHE Ethylene Producer's Conference titled “Cracking Heater Convection Retrofit with Integral SCR.” The subject of this paper will discuss the long term environmental benefits, performance, and maintenance of the installation of an integral SCR.