萘热解生焦过程的反应分子动力学模拟

Reactive Molecular Dynamics Simulation of Coking Process of Naphthalene

采用分子模拟的方法深入研究萘在热解生成针状焦过程的反应分子动力学。运用反应力场ReaxFF模拟该反应过程,并进行量子化学分析,推断得到萘分子在热解生焦过程中的主要反应历程。萘分子在自由基夺氢的情况下生成自由基·C10H7,·C10H7两两结合生成1,1'-联萘,1,1'-联萘再脱氢缩合生成苝,苝再进行脱氢缩合反应,芳核也随之增大。反应分子动力学模拟结果表明,在萘生焦过程中,反应生成的小分子和自由基会促进萘热解反应。在针状焦生成前期,应当控制热解反应的温度和压力,适当抑制气体挥发速率,以保证小分子和自由基能够参与芳核的生长反应。

Molecular simulation methods were employed for reactive molecular dynamics of naphthalene in the coking process to form needle coke.Reactive force field ReaxFF was used to simulate reactive molecular dynamics.In addition,quantum chemistry was used to analyze the simulation results.From the above results,naphthalene coking mechanism was proposed.During coking process,naphthalene can be deprived of a hydrogen atom by a radical,and lead to the formation of a new free radical·C10H7.Then,two radicals of·C10H7 react to form 1,1'-naphthalene.In the next step,perylene can be formed by 1,1'-naphthalene dehydrogenation.Furthermore,aromatic nuclei can grow through condensation and dehydrogenation of perylene.Based on the above mechanisms,it can be known that small molecules and radicals are very important in coke formation.In the early stage of needle coke formation,it is necessary to control temperature and pressure which have a significant impact on the evaporation rate of small molecules.Small molecules and radicals can participate in the growth of aromatic nuclei.