Abstract: Forced composition cycling experiments were carried out at 0.1MPa total pressure and 250℃. A maximum in the time-averaged selectivity-period curve was found at the period of about 1 min, being higher by 5% than its optimal steady state value. A cycling operation model including all kinetic parameters of elementary steps was used to simulate the dynamic process of forced composition cycling. The results of simulation showed that this model can predict a maximum in the time-averaged selectivity-period curve but the period at which the maximum was found was much less than 1 min. It suggested that cycling operation could probably cause a slow change in the bulk phase or/and on the surface of the catalyst.

摘要： 在原料气组成人为地呈周期性变化的情况下,对乙烯选择氧化反应动态操作的时间平均性能进行了系统地实验和模拟研究.实验发现存在着组成切换的最佳周期,可使环氧乙烷时间平均选择性比定常值提高5%.动态操作时间平均特性的模型预测与实验结果定性地一致,但是最佳周期的模型预测值远小于实验值,证明人为地、周期性地改变气体组成可能诱发了催化剂表面甚至体相中某些缓慢变化的过程.