小分子烃类蒸汽热裂解自由基机理模型研究方法的探讨

由于热裂解存在反应时间短、自由基数量多、浓度小，且不同原料产生的不同自由基之间、反应深度较大时管壁处于高温和停留时间所生成的不同自由基与主流体间的相互作用会随时改变反应路径，并影响到产物分布，因此造成了用实验方法研究单体烃热裂解反应机理的困难。将Materials Studio软件与Aspen Plus软件相结合来研究单体烃热裂解的自由基反应机理，并通过对乙烷热裂解一次反应机理、乙烷和丙烷混合热裂解相互作用机理、动力学数据准确性对比及正已烷空间位阻的影响，对研究方法进行了论述。结果表明，数值模拟的理论方法与实验方法相比，可以深入了解实验研究不可能达到的一些机理细节问题，如果将实验研究和模拟研究相结合，可避免目前动力学模型研究中的各种假设，提高机理模型研究的准确性，为工业生产预测提供高精度的机理模型。

Free radical models of small molecular alkane pyrolysis

Besides short reaction time, large variety and low concentrations of free radicals in alkane pyrolysis, interactions between different free radicals, which were produced by various raw materials, and between main streams and free radicals, which were produced near high temperature wall zone and stagnant residence time under high reaction depth, can spontaneously alter reaction paths and affect product distribution. Therefore, it is very difficult to study pyrolysis mechanism of hydrocarbons by experimental methods. Through integration of Materials Studio and Aspen Plus software, free radical mechanism of single hydrocarbon pyrolysis by molecular simulation techniques was studied. Research methodologies from initial free-radical mechanism of ethane pyrolysis, interaction mechanism of ethane and propane mixture pyrolysis, data accuracy of reaction kinetics, and steric hindrance in n-hexane pyrolysis were also evaluated. The results show that numerical simulation method can get a better understanding of some mechanistic details than experimental method and the combination of experimental and simulation methods can eliminate various hypotheses in current kinetic models and improve model accuracy, which will provide a high-precision mechanism model for industrial production forecast.