Jhong-Lin Wu 1,2,3, Ta-Chang Lin 1,2, Lin-Chi Wang4, Guo-Ping Chang-Chien5,6

  • 1 Department of Environmental Engineering, National Cheng Kung University, 1, University Road, Tainan, 70101, Taiwan
  • 2 Sustainable Environment Research Laboratories, National Cheng Kung University, 1, University Road, Tainan 70101, Taiwan
  • 3 Environmental Resource and Management Research Center, National Cheng Kung University, 1, University Road, Tainan 70101, Taiwan
  • 4 Department of Civil Engineering and Geomatics, Cheng Shiu University, 840, Chengching Road, Kaohsiung 83347, Taiwan
  • 5 Super Micro Mass Research and Technology Center, Cheng Shiu University, 840 Chengcing Road, Kaohsiung 83347, Taiwan
  • 6 Department of Cosmetic and Fashion Styling, Cheng Shiu University, 840, Chengching Road, Kaohsiung 83347, Taiwan

Received: May 30, 2013
Revised: August 18, 2013
Accepted: August 18, 2013
Download Citation: ||https://doi.org/10.4209/aaqr.2013.05.0179 

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Cite this article:
Wu, J.L., Lin, T.C., Wang, L.C. and Chang-Chien, G.P. (2014). Memory Effects of Polychlorinated Dibenzo-p-dioxin and Furan Emissions in a Laboratory Waste Incinerator. Aerosol Air Qual. Res. 14: 1168-1178. https://doi.org/10.4209/aaqr.2013.05.0179


 

ABSTRACT


Laboratory wastes are discharged from experimental, testing, or analysis processes, and contain various toxic chemical compounds with a high heating-value and a high chlorine content (> 9%). Elevated PCDD/F (polychlorinated dibenzo-p-dioxin and furan) emissions during start-up stages are caused by combustion of waste with high chlorine contents, incomplete combustion, and so called "memory effects". Even though the duration of cold start-up is short compared with the hours of continuous steady operation in a waste incinerator, its negative effects with regard to PCDD/F emissions on both human health and the environment cannot be neglected. A full-scale laboratory-waste incinerator which is operated for 10 days in each run and has 15 to 20 runs annually was investigated in this study. Eleven PCDD/F samples of stack flue gas were collected during the cold start-up periods (for 60.5 hrs). The gas temperature of the primary combustion chamber was above 850°C, and was maintained at between 850 and 900°C by injecting diesel fuel without waste feed. For first 1.5–7.5 hours, the PCDD/F concentration in the stack flue gas was as high as 0.656–1.15 ng I-TEQ/Nm3. Afterward, during hours 10.5–35.5 and 54.5–60.5, this reduced to 0.159–0.459 and 0.218–0.254 ng I-TEQ/Nm3, respectively. Based on principal component analysis (PCA) and the L/H ratio, the results revealed a higher L/H ratio (1.23) before hour 32, indicating that less chlorinated PCDD/F homologues (tetra and penta) dominated, while after hour 32 more chlorinated PCDD/F homologues (hexa, hepta and Octa) had a higher mass concentration and the L/H ratio fell to 0.42. These results indicate that the PCDD/F emissions during cold start-up were caused by memory effects and thermal desorption. Therefore, in order to reduce the PCDD/F emissions from the stack flue gas of waste incinerators, is highly recommended that a higher amount of activated carbon injection is used in front of the bag filters.


Keywords: PCDD/Fs; Incineration; Memory effect; Stack flue gas; Laboratory waste

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