Emissions of nitrogen oxides (NOx) from cement manufacturers continue to be targeted for reductions through a number of regulatory programs. These regulatory programs are discussed in this paper. In recent years, Selective Non-Catalytic Reduction (SNCR) has been tested at a number of cement plants, and has proven to be effective at reducing NOx emissions in some cases. Very recently, in 2005, several U.S. cement plants have begun installing and operating SNCR. This paper identifies these installations, as well as planned installations in the U.S. SNCR performance and costs are addressed. Also, operational and environmental issues with SNCR are discussed, including pros and cons of various reagents, ammonia slip, visible plumes, ammonium salt plugging and fouling and other issues. This paper also summarizes recent permitting activity in which SNCR is required (or expected to be required), including specifics of the required emission rates such as the NOx limit and averaging time.
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