Emission control and phase migration of PCDD/Fs in a rotary kiln incinerator:hazardous vs medical waste incineration  

作　　者：Ying Peng Yunfeng Ma Xiaoqing Lin Jisheng Long Xiaodong Li 

机构地区：[1]State Key Laboratory for Clean Energy Utilization,Institute for Thermal Power Engineering,Zhejiang University,Hangzhou,310027,China [2]Shanghai SUS ENVIRONMENT Co.,LTD,Shanghai,201703,China

出　　处：《Waste Disposal and Sustainable Energy》2023年第3期395-406,共12页废弃物处置与可持续能源（英文）

基　　金：supported by the National Key Research and Development Program of China(No.2020YFC1910100).

摘　　要：This study was carried out in a full-scale(50 t/d)rotary kiln incinerator to explore the removal characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/Fs)by different units of air pollution control devices(APCDs),and special interest was focused on the“memory effect”phenomenon of PCDD/Fs in the wet scrubber(WS),which usually caused an undesirable rise in PCDD/F emission concentrations.The general removal efficiency of PCDD/Fs by APCDs was 99.4%(from 14.11 at exhaust heat boiler(EHB)outlet to 0.09 ng I-TEQ/Nm^(3)at stack)under medical waste(MW)incineration condition,and 99.2%(from 19.91 to 0.16 ng I-TEQ/Nm^(3))under hazardous waste(HW)incineration condition.The PCDD/F concentrations in flue gas decreased along the APCDs except for WS,in which the“memory effect”was observed.In detail,WS largely increased the I-TEQ concentration of gas-phase PCDD/Fs from 0.047 to 0.188 ng I-TEQ/Nm^(3)in the flue gas,and the concentration of particulate-phase PCDD/Fs increased from 0.003 to 0.030 ng I-TEQ/Nm^(3).In addition,this study found that phase migration promoted the accumulation of PCDD/Fs in scrubbing water,and the flow entrainment phenomenon played a great role in causing the“memory effect”.The PCDD/F concentrations of fly ash collected from cyclone and fabric filter(FF)were as high as 4.23 and 6.99 ng I-TEQ/g,respectively,which had exceeded the national landfill limitation(3 ng I-TEQ/g)in China.The system balance calculations revealed that APCDs promoted the migration of PCDD/Fs from the gas-phase to the particulate-phase,which caused fly ash to be the main carrier of PCDD/Fs and led to excessive emissions.The results of this study can contribute to the optimized design of combustion conditions and system cleaning for controlling PCDD/F emissions from rotary kiln incinerators.

关 键 词：Air pollution control devices Wet scrubber Removal efficiency Memory effect Phase migration 

分 类 号：X51[环境科学与工程—环境工程]