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    热解参数对退役光伏组件背板产物组成及微观形貌的影响

    Effect of pyrolysis parameters on composition and microscopic morphology of product during pyrolysis of backsheet from waste photovoltaic modules

    • 摘要: 为推动退役光伏组件无害化处置与资源化利用技术迭代,破解光伏固废回收利用率低、污染控制难度大的行业难题,以光伏组件核心废弃物层压件背板为研究对象,开展热解特性及产物调控试验研究,系统探究热解温度、热解时间及氧化氛围三大关键工况参数对背板热解产物赋存分布、组分特征的影响规律。试验证实光伏背板的主要热解分解温度区间为400~600 ℃,热解温度对产物收率与能耗水平具有决定性影响。综合权衡液相资源化产物收率与体系反应能耗,研究确定光伏背板最优热解工艺温度为450 ℃。产物分析结果表明:背板热解液相产物以羧酸类物质为主,同时伴有少量含氟有机污染物,气相产物主要为一氧化碳与二氧化碳。延长热解停留时间能够诱发液相产物发生二次裂解反应,促使液相组分进一步转化为小分子气相产物,显著提升气相产物收率。氧化气氛可对背板热解过程产生明显的温度差异化调控作用,低温氧化条件可有效降低背板热解活化能,促进其低温分解并稳定生成液相与固相产物,高温氧化环境则会强化液相产物深度裂解过程,同时加剧热解焦炭的氧化消耗。微观形貌分析结果表明:背板热解过程依次经历融化软化、热解裂解、挥发分析出及碳化定型4个阶段,充分热解后的炭产物呈现蓬松多孔的微观结构,具备良好的后续资源化利用潜力。

       

      Abstract: To advance the technical development of harmless disposal and resource recovery for retired photovoltaic modules, this study investigates the pyrolysis behaviors of photovoltaic backsheets, which are typical waste materials from photovoltaic laminates. The effects of pyrolysis temperature, holding time and oxidative atmosphere on the distribution and composition of pyrolysis products were systematically explored. Experimental results indicate that the thermal decomposition of photovoltaic backsheets primarily occurs within the temperature range of 400–600 ℃, and pyrolysis temperature dominates product yield and energy consumption performance. By comprehensively considering liquid product yield and overall energy consumption, 450 ℃ was determined as the optimal pyrolysis temperature for backsheet treatment. Liquid pyrolysis products are mainly composed of carboxylic substances with a small amount of fluorine-containing organic compounds, while gaseous products principally consist of carbon monoxide and carbon dioxide. Extended pyrolysis duration induces secondary cracking of liquid components and promotes the conversion of liquid products into small-molecule gaseous products, thereby improving gas product yield. Oxidative atmosphere exerts distinct temperature-dependent effects on the pyrolysis process. Low-temperature oxidation reduces the activation energy of backsheet decomposition and facilitates the stable generation of liquid and solid products, whereas high-temperature oxidation intensifies the deep cracking of liquid products and accelerates the oxidation of pyrolytic char. Microscopic morphology analysis reveals that the pyrolysis procedure includes sequential stages of melting, thermal decomposition, volatile release and carbonization. Sufficient pyrolysis produces porous and fluffy char with promising potential for resource reuse. both liquid and solid products. However, high temperatures intensified the decomposition of liquid products and the oxidation of pyrolytic char. Based on the morphology of the pyrolytic char, it can be inferred that the backsheet pyrolysis undergoes stages of melting, pyrolysis, release of volatiles, and carbonization. And abundant loose and porous structures were obtained in pyrolytic char.

       

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