Analysis of Emission Characteristics and Emission Factors of Carbon Monoxide and Nitrogen Oxide Emitted from Wood Pellet Combustion in Industrial Wood Pellet Boilers Supplied According to the Subsidy Program of Korea Forest Service

Abstract

Korea Forest Service has supplied 76 industrial wood pellet boilers from 2011 to 2015 through subsidy programs. Since carbon monoxide (CO) and nitrogen oxides (NOx) generated during boiler combustion are substances that lead to death in the case of acute poisoning, it is very important to reduce emissions. Therefore, the CO and NOx emission values of 63 boilers excluding the hot air blower and some boilers initially supplied were analyzed. The emission factor was also calculated from the measured exhaust gas concentration (based on exhaust gas O2 concentration of 12%). The average value of CO emitted from industrial wood pellet boilers was 49 ppm and it was confirmed that the CO concentration was decreasing as the years passed. The emission factor of CO was 0.73 g/kg. The average value of NOx emitted from industrial wood pellet boilers was 67 ppm and the emission factor of NOx was 1.63 g/kg. Unlike CO, there was no tendency to decrease according to the installation year. Both CO and NOx measurements met the limits of the Ministry of Environment. These NOx emission factors were compared with the NOx emission factors produced by certified low NOx burners. The NOx emission factor of industrial wood pellet boilers was about 1.9 times that of certified low NOx LNG combustors and about 0.92 times that of coal combustion.