生活垃圾焚烧飞灰等离子熔融过程氯元素的迁移转化特性研究

Study on the Transformation Characteristics of Chlorine During Plasma Vitrification of Municipal Solid Waste Incineration Fly Ash

等离子熔融技术是生活垃圾焚烧飞灰减量化、无害化、资源化最有效的技术之一。为探明飞灰等离子熔融过程中氯元素的迁移转化特性,采用热力学分析和管式炉高温熔融实验,考察了熔融温度、气氛、组分等对飞灰熔融过程氯元素迁移转化规律的影响。热力学分析与管式炉高温熔融实验结果基本一致,温度的升高和气氛中O_(2)的加入均有助于飞灰中氯元素释放率和HCl占总释放氯比率的增加,飞灰中SiO_(2)和Al_(2)O_(3)的加入有助于玻璃体含氯量的降低。飞灰等离子熔融中试试验结果显示,99.7%的氯进入气相产物,其中NaCl(g)、KCl(g)、CaCl_(2)(g)中的氯占69.3%,HCl(g)中的氯占30.4%;剩余0.3%的氯进入玻璃体中。通过本文的研究,为实际飞灰等离子熔融项目中有效控制氯元素转化和降低玻璃体含氯量提供指导。

Plasma vitrification technology is one of the most effective technologies for the reduced,harmless and resource disposal of municipal solid waste incineration(MSWI)fly ash.In order to find out the transformation characteristics of chlorine during the process of plasma vitrification of fly ash,the effects of temperature,atmosphere and composition on the transformation of chlorine were investigated by means of thermodynamic analysis and high temperature melting experiment in tube furnace.The results of thermodynamic analysis are basically consistent with the results of high temperature melting experiment in tube furnace.The increase of temperature and the addition of O_(2) in atmosphere are helpful to the increase of chlorine release rate and the ratio of HCl to total chlorine release for fly ash.The addition of SiO_(2) and Al_(2)O_(3) in fly ash is helpful to the decrease of chlorine content in the vitreum.The results of pilot tests of plasma vitrification of fly ash show that 99.7%of chlorine enters the gas phase products,of which 69.3%is in NaCl(g),KCl(g)and CaCl_(2)(g),and 30.4%is in HCl(g);the remaining 0.3%of chlorine enters the vitreum.This research can provide guidance for effectively controlling the transformation of chlorine and reducing the chlorine content of vitreum in the industrial project.