The Effects of Air Pollution Control Devices on the Dioxin Emissions from Municipal Waste Incinerators

• Main Authors: Jung-Jeng Lin, 林忠正
• Other Authors: Moo-Beng Chang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/28030143389163918232

碩士 === 國立中央大學 === 環境工程研究所 === 88 === Due to the rapid increase of municipal solid waste in Taiwan, the government has enacted the policy of building large-scale municipal solid waste incinerators (MWIs) since 1984. The percentage of municipal waste to be incinerated will be greater than 90% after 2004. Because of the incineration of municipal solid waste (MSW) is the most important source of dioxin, the dioxin emission from the MWIs has caused much public concerns. Development of effective dioxin control technology is essential for the successful waste management plan. In this study evaluation of the dioxin removal efficiency of the air pollution control device (APCD) at two existing MWIs in Taiwan is conducted via stack sampling and analysis. MWI-A is equipped with electrostatic precipitators followed by wet scrubbers while MWI-B is equipped with cyclones, dry lime scrubbing systems and fabric filters as APCDs. Results indicate that the patterns of dioxin isomers at APCD inlet and stack are similar for both MWIs. The dioxin concentration at APCD inlet of MWI-B is 2.75 times higher than that of MWI-A, but it’s similar at stack. This indicate that the concentration of dioxins generated at MWI-A is higher than that of MWI-B as the gas stream flows through APCD. Dioxin removal efficiency at MWI-A is negative because the operating temperature of the APCD falls in the de novo reaction window (200~350°C). During the first year of carbon injection, the concentrations of emitted dioxin decrease greatly at MWI-B. The dioxin removal efficiency increases from 5.88% to 87.63 and 91.28 %, respectively compared to the condition without activated carbon injection. At the second year, the dioxin removal efficiency reaches 98.6% after injecting 43.4 mg/Nm3 of activated carbon. The lower efficiency at the first year can be attributed to the memory effect, i.e. the dioxin or precursor desorbs slowly to the flue gas and increases the dioxin concentration at stack, resulting in lower dioxin removal efficiency than expected.