C8芳烃异构化催化剂内气相有效扩散系数的计算

针对C₈芳烃异构化反应中二甲苯等6种反应物在催化剂内的扩散过程，建立一种气相有效扩散系数的计算方法。根据此方法计算得到不同反应压力和温度的条件下，C₈芳烃异构化反应体系中6种气相物质在催化剂内扩散的有效扩散系数，验证了方法的可靠性，并讨论了温度和压力对分子扩散系数的影响，结果表明：随着压力增大，气体密度增大，分子间距变小，分子间作用力变大，分子扩散系数减小；而根据分子运动论，随着温度的升高，气体运动速率和扩散速率都会变大，分子扩散系数增大。

CALCULATION OF EFFECTIVE DIFFUSION COEFFICIENT OF GAS PHASE IN C8 AROMATICS ISOMARIZATION CATALYST

A method for calculation of effective diffusion coefficient of gas phase was established. According to this method, the effective diffusion coefficients of the six gases such as xylene in C₈ aromatics isomerization catalyst under different reaction pressures and temperatures were estimated. The reliability of the method was verified and the effects of temperature and pressure on the molecular diffusion coefficient were discussed. The results showed that as the pressure increased, the gas density increased, the molecular distance shortened, the intermolecular force became larger, and the molecular diffusion coefficient decreased; while as the temperature was up, the molecular diffusion coefficient increased.