核电站检修用PVC塑料布微波热解技术及机理分析

Microwave Pyrolysis Technology and Mechanism Analysis of PVC Film for Nuclear Power Plant Maintenance

针对核电站检修用PVC塑料布的减容处理,建立了大功率微波热解减容技术及设备,通过对微波减容实验过程中的尾气成分分析,详细研究了PVC塑料布的微波热解技术条件及机理,并与PVC常规热解行为及机理进行了比较。结果表明,在微波照射条件下,PVC分解过程分为3个阶段:80~140℃为脱HCl阶段;140~250℃为裂解碳化阶段;250℃以上为灰化阶段。与常规热解相比,微波照射可使PVC塑料布在较低温度下迅速脱氯,并可通过调节微波加热功率,控制升温程序,从而显著降低PVC塑料布热解过程中二噁英的产生。

A high power microwave pyrolysis system for reducing the volume of PVC film wastes used for nuclear power plant maintenance was established. The technical conditions and mechanisms of microwave pyrolysis of PVC film wastes were studied in detail through analyzing the components of gas products in microwave pyrolysis of PVC film waste volume reduction experiment. The results showed that under microwave irradiation, the decomposition process of PVC film wastes could be divided into three stages: The first stage was dehydrochlorination at temperature of 80-140 ℃. The second stage was the pyrolysis and carbonization from 140 ℃ to 250 ℃. The third stage was incineration at high temperature above 250 ℃. Compared with the conventional heating method, microwave irradiation can dechlorinate PVC film rapidly at lower temperature, and control the heating power, thus significantly reducing the production of dioxin in the pyrolysis process of PVC film.