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EVALUATION OF PRIMARY AIR VITIATION FOR NITRIC OXIDE REDUCTION IN A ROTARY CEMENT KILN. VOLUME 1. TECHNICAL REPORT
Citation:
Benson, R. AND S. Hunter. EVALUATION OF PRIMARY AIR VITIATION FOR NITRIC OXIDE REDUCTION IN A ROTARY CEMENT KILN. VOLUME 1. TECHNICAL REPORT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-86/034A.
Description:
The report gives results of tests to evaluate combustion modifications for nitric oxide (NO) reduction and cement product quality in a pilot-scale long-dry-process cement kiln firing pulverized coal. The kiln is rated at 11.35 kg/s (1080 tons/day) of cement with a thermal input rate of 70.3 MW (240 million Btu/hr). Of the combustion modifications evaluated in previous studies, vitiation of the primary air with inert gas (nitrogen) was considered the best alternative for NO reduction on a pilot-scale kiln. The percent reduction was established from a reference baseline of 1050 ppm (corrected to 3% O2) and a kiln exit oxygen of 1.82%. The NO volumetric emissions were lowered to 880 ppm (corrected to 3% O2) with a kiln exit oxygen of 0.7%. NOx reductions during the short term nitrogen injection tests were about 25-30% with no adverse effects on product quality. Because of the interacting feed chemistry/kiln operations, it was not possible to clearly isolate the effect of nitrogen injection.