PCDD/F从头合成的影响因素和抑制方法

Influence factors and control means of de novo synthesis of PCDD/F

通过对垃圾焚烧过程中PCDD/F的从头合成条件和影响因素进行分析,总结了CuCl2、未燃尽C元素、O2分压和温度等对PCDD/F从头合成的影响规律。发现CuCl2是各因素中影响最大也最为明显的催化剂;250～450℃是PCDD/F从头合成的适宜温度区间,在300℃左右时合成量达到最大值。总结了抑制PCDD/F从头合成的具体方法和措施,在此基础上成功研制了一台日处理能力为3t/d的医疗垃圾热解装置,通过对产生的热解气和固体残留物抽样化验,表明该装置能够将大部分HCl、SO2等有害成分固化在垃圾热解后剩余的残渣中,而热解气中所含的HCl、SO2等物质则很少,远低于国家规定的有关标准,能够较好地抑制PCDD/F的从头合成,减少对环境造成的二次污染。

The conditions and influence factors of de novo synthesis of polychlorinated dibenzodioxin and dibenzofuran （PCDD/F） in municipal waste incinerators were analyzed. The influence of CuCl2, carbon content, partial pressure of oxygen, reaction temperature and time on the de novo synthesis of PCDD/F were studied. The results indicated that CuCl2 was the most obvious and effective activator. The de dovo synthesis of PCDD/F was favored within a temperature range from 250℃ to 450℃ and a maximum value was reached at 300℃. Measurements and methods were proposed to reduce the PCDDfF formation. A new typical medical waste pyrolysis equipment （3t/d） was designed and developed, and the pyrolysis gas and solid residue were tested .The results showed that most of the HCl, SO2 generated during the pyrolysis process was fixed in the residue, and there was little HCl and SO2 left in the pyrolysis gas, which was much lower than the Chinese standard for emission.