30 t/d新型村镇垃圾热解气化炉二噁英排放特性

针对目前处置村镇垃圾的小型热处理炉运行不稳定、排放难以达标等问题,介绍了一种新型村镇垃圾热解气化炉(30 t/d),并对其系统烟气及炉渣的二噁英生成排放特性进行研究。结果表明:炉渣中的二噁英浓度为0.723 μg I-TEQ/kg,可满足GB 16889-2008《生活垃圾填埋场污染控制标准》中二噁英排放的要求;在正常喷射活性炭时尾部烟气二噁英浓度为0.029 ng I-TEQ/Nm3,低于GB 18485-2014《生活垃圾焚烧污染控制标准》中二噁英排放限值;气化燃烧过程的烟气二噁英原始排放浓度较低,低温异相合成反应是该垃圾炉烟气二噁英的主要来源;在质量浓度分布上占优势的为高氯代PCDD/Fs,对总毒性当量起主导作用的为2,3,4,7,8-PeCDF,喷射活性炭对二噁英具有良好的去除效果。以期为村镇垃圾热解气化规范处置提供示范,并为热解气化炉二噁英排放控制提供参考。

DIOXIN EMISSION CHARACTERISTICS OF A NOVEL 30 t/d VILLAGE AND TOWN-SCALE SOLID WASTES GASIFICATION SYSTEM

Aiming at the problems of unstable operation and unqualified emission of small heat treatment furnaces for the disposal of rural domestic wastes, a new type of pyrolysis gasification incinerator for rural solid wastes was introduced, and the dioxins emission characteristics of flue gas and slag in a novel 30 t/d solid wastes gasification system were studied. The results were as follows:the emission of dioxin from slag was 0.723 μg I-TEQ/kg, which met the requirements of Standard of Pollution Control on the Landfill Site of Municipal Solid Waste (GB 16889-2008). When spraying activated carbon normally, the concentration of dioxin in tail flue gas was 0.029 ng I-TEQ/Nm3, lower than the dioxin emission limitation of Standard for Pollution Control on the Municipal Solid Waste Incineration (GB 18485-2014). The original emission concentration of dioxin from flue gas in the gasification and combustion process was low, and low-temperature heterogeneous synthesis reaction was the main source of dioxin in flue gas of the furnace. Furthermore, high chlorinated PCDD/Fs was dominant in mass concentration distribution, and 2,3,4,7,8-PeCDF played an important role in total toxic equivalent. Besides, spraying activated carbon had a good removal effect on dioxins. This study provided a demonstration for the standardized disposal of pyrolysis and gasification for rural domestic wastes, and a reference for dioxin emission control of the pyrolysis and gasification furnace.