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

6.2.2.2 Selective Catalytic Reduction. Although no
selective catalytic reduction (SCR) systems are currently being
used on cement plants in the United States, this control
technique has been applied successfully in other industries.
Capital costs for this control approach would include cost of the
SCR unit, ammonia storage tank, and an ammonia heating/
vaporization injection system along with equipment needed for
preheating flue gases to an appropriate temperature. Operating
costs would include the cost of ammonia reagent, dilution steam,
catalyst replacement and disposal costs, and energy cost
associated with reheating the kiln exhaust gases as well as the
operating labor and maintenance costs.
Since the SCR technology has not been proven in cement
plants in the United States, approximate capital and operating
costs as applicable to the model plants were not available from
any of the SCR control system vendors in the United States. An
equipment cost estimate of an SCR system was submitted by a
Japanese supplier to a cement company in the United States in
1991.19 For a dry long kiln with 1,120 tons/day (47 tons/hr)
clinker capacity, the estimated equipment cost was 1 billion/Yen.
With a current exchange rate of 108 Yen/$ and assuming 5 percent
inflation, the estimated cost in 1992 U.S. dollars was about 9.72
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