The Estimation of Emission Factor of N2O and CH4by Measurement from Stacks in the Waste Incinerators and Cement Production Plants

Abstract

The purpose of this study is to estimate the emission factor of non-CO₂ global warming gases such as N₂O and CH₄ by measuring concentrations from stacks of waste incinerators and cement production plants. Based on the established monitoring methods, N₂O concentration measured from stacks in incinerator were between 0.62 and 40.60 ppm v (ave. 11.50 ppm v ). The concentration of N₂O was dependent on the incinerator types. However, the concentrations of CH4 gas were between 2.65 and 5.68 ppm v (ave. 4.22 ppm v ), and did not show the dependency on the incinerator types. In the cement production plant, the concentration ranges of N₂O from the stack were from 6.90 to 10.80 ppmv (ave. 8.60 ppm v ), and CH4 were between 1.80 and 2.20 ppm v (ave. 2.60 ppm v ). Using measured concentrations, the emission amounts of N2O and CH4 from stacks per year were calculated. The results were is 4.2 ton N₂O/yr in the incinerators, and 53.7 ton N₂O/yr in the cement facilities. The big difference is from the flow rate of flue gas in the cement facilities compared to the incinerators. By the same reason, the CH₄ emission amounts in cement plant and incinerator was found to be 339 ton CO₂/yr and 34.1 ton CO₂/yr, respectively. Finally, the emission factor of N2O in the incinerators were calculated using the measured concentration and the amount of incinerated wastes, and was 42.5~799.1 g/ton in kiln and stoker type, 11.9~79.9 g/ton in stoker type, 90.1 ton/g in rotary kiln type, 174.9 g/ton in fluidized bed type, and 63.8 g/ton in grate type, respectively. Also, the emission factors of CH₄ were found to 65.2-91.3 g/ton in kiln/stoker type, 73.9-122 g/ton in stoker type, 109.5 g/ton rotary kiln, and 26.1 g/ton in fluidized bed type. This result indicates that the emission factor in incinerators is strongly dependent on the incinerator types, and matched with result of IPCC (International Panel on Climate Change) guideline.