1-戊烯热裂解反应机理的数值模拟

Molecular simulation on pyrolysis mechanism of 1-pentene

运用Materials studio分子模拟软件和Aspen plus过程模拟软件相结合的方法,首次对大分子烯烃(1-戊烯)热裂解自由基机理进行模拟。利用Materials studio软件将1-戊烯进行结构优化,通过C—C键和C—H键长的分析,初步得到各自由基反应,并通过进一步计算得到活化能和指前因子等参数,再利用Aspen plus进行过程模拟得到产物浓度分布。结果表明:1-戊烯经过Materials studio模拟软件结构优化得出可能发生的链引发路径有5条,可能发生的热裂解自由基反应共42个,经过Aspen plus软件对单一路径和总路径进行模拟计算,从而简化甄选出17个主要的自由基反应,这17个自由基反应构成了由1-C_5H_9·-3、1-C_5H_9·-4、1-C_5H_9·-5的3个自由基形成的4个循环反应。1-C_5H_9·-3断C-C键形成循环1,生成1,3-C4H6和CH4;1-C_5H_9·-4断C—H键形成循环2,生成主要产物C2H4和CH4,同时断C-C键形成循环3,生成C3H6和C2H4;1-C_5H_9·-5断C—C键形成循环4,生成C2H4和C3H6。经验证,简化模型是可行的,为大分子烯烃热裂解机理的研究提供了一个新的研究思路。

Using Materials studio molecular simulation software and Aspen plus process simulation software, the mechanism of free radical pyrolysis for macro-molecular olefins（ 1-pentene） was simulated for the first time. First of all,the structure of 1-pentene was optimized by Materials Studio software,the types of free radical reaction were acquired by analyzing the length of C-C bond and C-H bond,the parameters such as activation energy and pre-exponential factor wereobtained by calculations,and then the product distribution was gained using Aspen plus process simulation. The research results showed that 5 chain initiation reactions and 42 free-radical reactions may occur in the thermal cracking of 1-penene,among which 17 free-radical reactions were defined according to the calculation,and 1-C5H9·-3、1-C5H9·-4 and 1-C5H9·-5 composed of four chain transfer cycle in the 17 reactions. The decomposition of 1-C5H9·-3 by the break of C-C bond created cycle 1,with the productions of 1,3-C4 H6 and CH4. The decomposition of 1-C5H9·-4 by the break of C-H bond created cycle 2,with the main productions of C2 H4 and CH4,while cycle 3 occurred by the break of C-C bond,with the productions of C3 H6 and C2 H4. The decomposition of 1-C5H9·-5 by the break of C-C bond created cycle 4,with the productions of C2 H4 and C3 H6. It was proved that the simplified model was feasible which provided a new research idea for the study of pyrolysis mechanism of macromolecular olefins.