Thirty-day Field Tests of Industrial Boilers: Site 3 - Pulverized-coal-fired Boiler

摘要

This is a final report for a test program to evaluate the long-term effectiveness of combustion modifications for lowering emissions from industrial boilers. Previous short-term test had been performed on industrial boilers to determine the effect of combustion modifications on such air pollutant emissions as NOx, SOx, CO, HC, and particulate. The objective of this program was to determine if the combustion modification techniques which were effective for the short-term tests are feasible for longer periods. The report gives results of a 30-day field test of a pulverized-coal-fired, water-tube boiler rated art 76.2 MW (260,000 lb steam/hr) output. Staged combustion air and low excess air were used to effectively control NOx emissions. However, such additional operational problems as flame instability can be encountered. The baseline NO measurement was 498 ng/J (815 ppm at 3% O2, dry) with the unit operating at about 70% of capacity. At the same load low NOx operations yielded NO at an emission level of 422 ng/J (691 ppm at 3% 02, dry) for a 15% NO reduction. During 30 days of firing under low NOx operation with loads of 15 to 63 MW, the average NO emission level was 340 ng/J (557 ppm at 3% O2, dry). Boiler efficiency increased about 1% under low NOx firing conditions.