乙苯裂解机理和超临界压力下的动力学模拟

基于乙苯燃烧机理的去氧处理获得的乙苯裂解机理, 采用QRRK/MSC算法代码对小分子产物的高压裂解相关参数进行改进, 构建了高压条件下乙苯裂解的136个物种及626步反应的机理. 在超临界压力和高温条件下的动力学模拟表明, 乙苯裂解机理的气相分子产率和转化率的模拟结果与实验结果相吻合. 采用敏感度分析对机理的控速步骤进行验证, 考察了机理中的关键反应, 结果表明本机理能较好地预测高压实验结果, 可应用于超临界裂解换热的计算模拟.

Kinetics Simulation of Ethylbenzene Pyrolysis Under Supercritical Pressure†

Based on pyrolysis mechanism of ethylbenzene, QRRK/MSC algorithm codes were adopted to improve the related parameters of small molecular products under high pressure condition. It was found that the conventional reactions which were only suitable for the low pressure conditions could modified to discribe the performance at high pressure conditions. A pyrolysis mechanism of ethylbenzene containing 136 species and 626 steps was developed. The kinetics modeling was carried out under the supercritical pressure(4 MPa) and the temperatures of 700, 750 and 780 ℃, respectively. The product prediction and the reaction pathway analysis were used to describe the pyrolysis process. It was found that the gas yield and the conversion rates by simulation were consistent with the experimental ones. Contributions of production pathway and the percentage of decomposion pathway were calculated to analyze and verify the craking reactions. Furthermore, through the sensitivity analysis, the rate determing steps of the pyrolysis mechanism of ethylbenzene were verified and the key reactions in the mechanism were examined. Some main types of reactions about selected reactions were described in detail.