废光伏组件乙烯-醋酸乙烯酯共聚物热解研究

Study on thermal decomposition of ethylene-vinylacetate copolymer in waste photovoltaic modules

中国是光伏组件的生产大国,报废后的光伏组件将会产生大量的固体废弃物,分解乙烯-醋酸乙烯酯共聚物(EVA)是光伏组件热解的关键。利用热重(TG)分析仪和管式炉对废光伏组件中的EVA进行热解实验,研究了EVA的失重特性、TG曲线与管式炉实验的失重率差异和不同温度下气、液、固产物分布情况。结果表明,EVA在两种气氛(空气、氮气)下的TG曲线均为2阶段失重,失重率在99%以上。在管式炉实验中,温度为350℃时,氮气和空气气氛的失重率相差不大;400℃时氮气气氛下EVA在管式炉实验的失重率(25.85%)高于TG实验(22.32%),空气气氛下管式炉实验的失重率(25.58%)低于TG实验(29.07%);450℃时,氮气和空气气氛下管式炉实验中EVA的失重率远大于TG实验,500℃时两种气氛下管式炉实验中失重率均在99%以上。随着温度的升高,液体产物和气体产物也随之增加,固体质量随之降低。

China is a major producer of photovoltaic modules,and the discarded photovoltaic modules will generate a large amount of solid waste.Ethylene-vinyl acetate copolymer(EVA)is the key to the heat treatment of photovoltaic modules.Thermogravimetric(TG)analyzer and tube furnace were used to conduct thermal decomposition experiments on EVA in waste photovoltaic modules.The weight loss characteristics of EVA,the difference between TG curve and weight loss rate of tube furnace,and the distribution of gas,liquid and solid products at different temperatures were studied.The results showed that the TG curve of EVA under the two atmospheres(air,nitrogen)was two-stage weight loss,and the weight loss rate was above 99%.In the tube furnace experiment,when the final temperature was 350℃,the weight loss rate of nitrogen and air atmosphere was not much different.At the final temperature of 400℃,the weight loss rate of EVA in tube furnace under nitrogen atmosphere(25.85%)was higher than that of the TG experiment(22.32%),and the weight loss rate of EVA in the tube furnace under air atmosphere(25.58%)was lower than that of the TG experiment(29.07%).At the final temperature of 450℃,the weight loss rate of the tube furnace under nitrogen and air atmosphere were much larger than that of the TG experiment.When the final temperature was 500℃,the weight loss rate in the tube furnace experiment under both atmospheres were more than 99%.As the temperature increased,the liquid products and gas products increased,and the solid mass decreased.