Reduction of NO.sub.x emissions from rotary cement kilns by selective noncatalytic reduction

摘要

The use of urea injection SNCR is enabled for rotary kilns of the type used to produce cement clinker. Rotary kilns are long cylinders that rotate about an inclined axis, with cement premix fed in at one end and a burner for heat at the other end. The geometry of the kilns and temperatures at the ends make introduction of ammonia or urea solutions ineffective or totally impractical. Urea prills can be injected at an initial velocity of at least 25, typically greater than 100, meters per second to reach into the kiln where a suitable temperature window for NO. sub.x reduction can be found.