Co-pyrolysis characteristics and kinetics of coal and plastic blends
Co-pyrolysis characteristics and kinetics of coal and plastic blends
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DOI：
10.1016/j.enconman.2008.10.007
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发表时间：
2009-03
影响因子：
10.4
通讯作者：
Liming Zhou;Taian Luo;Qunwu Huang
中科院分区：
文献类型：
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作者：
Liming Zhou;Taian Luo;Qunwu Huang
采用热重分析法研究了不同塑料（高密度聚乙烯、低密度聚乙烯和聚丙烯）与低挥发分煤（LVC）及其混合物的共热解行为。实验在N2气氛下以20°C/min的加热速率从室温到750°C进行。结果表明，塑料的热降解温度范围为438-521°C，煤的热降解温度范围为174-710°C。塑料由于其分子结构中相似的化学键而表现出相似的热解特性。煤与塑料的热分解温度区间重叠，为煤热解产生的自由基参与塑料的热分解反应提供了条件。热解温度高于530°C时，热解过程中的协同效应主要发生在高温区，热解过程中各组分的失重率的代数和ΔW为2.0-2.7%.根据Coats和Redfern一级反应法进行动力学研究。结果表明，HDPE、LDPE和PP的热解过程可用一级反应来描述。然而，对于LVC和LVC/塑料共混物，该过程可以分别由三个和四个连续的一级反应来描述。估计的动力学参数即，煤、塑料及其共混物的活化能和指前因子分别在35.7-572.8kJ/mol和27-1.7× 1038 min −1的范围内。
Co-pyrolysis behaviors of different plastics (high density polyethylene, low density polyethylene and polypropylene), low volatile coal (LVC) and their mixtures were investigated by TGA. Experiments were conducted under N2atmosphere at heating rate of 20°C/min from room temperature to 750°C. The results showed that the thermal degradation temperature range of plastic was 438–521°C, while that of coal (LVC) was 174–710°C. Plastics showed similar pyrolysis characteristics due to similar chemical bonds in their molecular structures. The overlapping degradation temperature interval between coal and plastic provide an opportunity for free radicals from coal pyrolysis to participate in the reactions of plastic decomposition. The difference of weight loss percent (ΔW) between experimental and theoretical ones, calculated as an algebraic sum of those from each separated component, ΔW is 2.0–2.7% at the pyrolysis temperature higher than 530°C, which indicates that the synergistic effect during pyrolysis occurs mainly in the high temperature region. The kinetic studies were performed according to Coats and Redfern method for first-order reaction. It was found that for plastics (HDPE, LDPE and PP), the pyrolysis process can be described by one first-order reaction. However, for LVC and LVC/plastic blends, this process can be described by three and four consecutive first-order reactions, respectively. The estimated kinetic parameters viz., activation energies and pre-exponential factors for coal, plastic and their blends, were found to be in the range of 35.7–572.8kJ/mol and 27–1.7×1038min−1, respectively.