茉莉花茶废弃物热解特性及动力学研究

文章以茉莉花茶废弃物作为研究样品, 通过热重分析仪在 $ 300 \sim 1200 \, K $ 的惰性气氛中、在 5 种加热速率 $ (10, 20, 30, 40, 50 \, \text{K/min}) $ 下进行实验, 利用 model-free 方法和 model-fitting 方法计算样品的热解动力学参数。通过三组分平行模型和 SCE (shuffled complex evolution) 优化算法对动力学参数进行优化分析。结果表明, 随着加热速率的升高, 微商热失重 (derivative thermogravimetric, DTG) 曲线具有阶段性和相似的变化趋势。通过 model-free 方法计算的结果接近, 且拟合结果良好, 整体活化能平均值为 $ 168.47 \, kJ/mol $。根据活化能的变化可划分为变化稳定的阶段 1 和快速增长的阶段 2, 阶段 1 可视为受单一反应模型影响, 阶段 2 则对应于多个反应的同时发生。阶段 1 的热解机理遵循扩散模型, 活化能平均值为 $ 85.31 \, kJ/mol $。该 SCE 优化算法的优化结果与实验数据具有良好吻合性, 且适用于多个加热速率下的实验数据。

The jasmine tea waste was taken as the research sample, and the experiments were carried out under five heating rates(10, 20, 30, 40 and 50 K/min) in an inert atmosphere of 300-1 200 K using a thermogravimetric analyzer. The pyrolysis kinetic parameters of the samples were calculated by model-free methods and model-fitting methods. The kinetic parameters were optimized and analyzed through three-component parallel model and shuffled complex evolution (SCE) optimization algorithm. With the increase of heating rate, the derivative thermogravimetric (DTG) curves have staged and similar trend. The results calculated by the model-free methods are close and well-fitting, and the average value of the overall activation energy is 168.47 kJ/mol. According to the change of activation energy, it can be divided into stable change stage (stage 1) and rapid growth stage (stage 2). Stage 1 can be determined by a single reaction model, while stage 2 corresponds to the simultaneous occurrence of multiple reactions. It is found that the pyrolysis mechanism at stage 1 follows the diffusion model, with the average activation energy of 85.31 kJ/mol. The optimization results of the SCE optimization algorithm are in good agreement with the experimental data, and are applicable to the experimental data at multiple heating rates.