Selective Non-Catalytic Reduction (SNCR) Systems
	Selective Catalytic Reduction (SCR) Systems
	Hybrid Systems
	Cold Flow Modeling

The SNCR process removes NO_x from combustion effluents by reducing nitric oxide (NO) to nitrogen and water. An aqueous solution of urea or aqueous NH₃ and NH₃ vapor is injected into the combustion effluents to supply the chemical agents for NO reduction. Free radicals produced by the injected reagent reduce NO to N₂ and H₂O throughout the temperature range of 1,600^oF to 2,000^oF, but maximum NO removal is achieved in a narrow temperature window of 1,700^oF to 1,800^oF. The technology is low cost and has no adverse impact on boiler operation (increase in pressure drop, derate, etc.).

Urea injection for NO removal was developed under sponsorship by the Electric Power Research Institute (EPRI). The full-scale commercialization began in 1985 with co-funding from San Diego Gas and Electric (SDG&E), Southern California Edison (SCE), Los Angeles Department of Water and Power (LADWP), Pacific Gas and Electric Company, Consolidated Edison, and Empire State Electric Energy Research Company. Applied Utility Systems, Inc. (AUS) was the prime contractor for much of this pioneering work through the completion of full-scale commercialization in 1989 at the 110 MW SDG&E Encina Unit 2.

The AUS urea injection technology has advanced significantly since 1989. Full-scale turnkey installations by AUS have successfully reduced NO in gas- and oil-fired boilers as large as 320 MW. Based on these results, both SCE and LADWP have installed a total of 20 commercial urea injection systems that were designed by AUS. These commercial systems have achieved more than 70 percent NO removal at some conditions, and the NO removal has exceeded 40 percent at all boiler operating conditions for some installations. AUS has also designed a commercial urea injection system for two (2) 750 MW coal-fired boilers at the SCE Mohave Generating Station.

The AUS technology for the SNCR process is based on a proven record of successful development and commercial implementation. This record includes a wide range of pioneering applications for urea injection in accordance with the original disclosures in U.S. Patent Number 4,208,386 that is assigned to EPRI. Extensive knowledge gained by AUS during the completion of these projects has established the Company as an industry leader in providing SNCR systems.