NOx Emissions from Cement Mfg - US Environmental Protection ...

6.2.2 Postcombustion Control Approaches for NOx Emissions
Control
6.2.2.1 Selective Noncatalytic Reduction. Although no
selective noncatalytic reduction (SNCR) systems are currently
being used on cement plants in the United States, this control
technique has been applied successfully in other industries. Due
to difficulties in continuous injection of reagent in a rotating
kiln, SNCR technology is considered to be applicable only to
preheater/precalciner kilns. Two types of SNCR systems are
commercially available based on either ammonia- or urea-based
reagents. The capital costs of this control technique primarily
include cost of an injection system for either ammonia- or urea-
based reagent, delivery system plus storage tanks, and control
instrumentation. Operating costs include the cost of reagents
and additives used, additional electricity cost for reagent
pumping, and fuel penalty cost along with operating labor and
maintenance requirements. As discussed in Section 5.2.2, SNCR
process is considered applicable only for preheater and
precalciner types of cement kiln processes.
The equipment and operating costs of urea-based reagent
systems as applicable to model plant #6 and #8 were obtained from
two sources.15,16 Both of these cost estimates were comparable. Costs
PEC for model 1
PEC for model 2 '
NO x emissions for model 1
NO x emissions for model 2
were developed for model plant #5 and #7 using the 0.6 power rule:
6-33
0.6
.