甲烷部分氧化过程中强制振荡的动力学Monte Carlo模拟

为了有效控制动力学振荡行为以提高反应的转化率, 利用Monte Carlo 方法研究了甲烷催化部分氧化过程中的强制振荡行为, 探讨了原料气周期性变化对振荡动力学和转化率的影响. 研究表明原料气周期性变化不仅可以有效调控振荡的动力学行为, 产生如短周期振荡和双峰振荡等特殊动力学过程, 而且还可以提高反应的转化率. 当强制过程的周期从T/3 增大到2T(T为自发振荡过程的平均周期), 振荡过程从短周期振荡变化为双峰振荡. 对反应过程中CO的转化率进行了计算, 结果表明原料气周期性变化可以有效提高反应的转化率.振荡动力学的改变和转化率的提高主要是因为强制振荡过程使得催化剂表面发生了从氧化态向还原态的转变.

A Kinetic Monte Carlo Simulation on Forced Oscillations of Methane Partial Oxidation

To control the kinetic oscillations for the purpose of obtaining a high conversion rate, external forcing of methane oxidation on metal catalysts was studied with kinetic Monte Carlo simulations. The influence of composition cycling of the feed on the dynamics and conversion rate was investigated. The results showed that the composition cycling of feed cannot give rise to different kinetic behavior, such as short periods or doublepeaks, but does bring about a higher conversion rate. It was shown that with forcing periods from T/3 to 2T (T is the average period of autonomous oscillations), the oscillations changed from short periods and small amplitudes to typical double-peak oscillations. The conversion rate can also be calculated, and the results showed that the mean conversion was slightly higher with forced oscillations. The changing of the kinetics can be attributed to phase transition of the metal catalysts from the oxidized surface to a partially reduced state.