加氢裂化预处理催化剂按活性级配顺序的实验研究

基于加氢裂化预处理催化剂在不同分区反应规律，按催化剂活性由低到高和由高到低设计2种级配方案。以常规减压蜡油(VGO)为原料，对比考察2种级配方案加氢裂化预处理催化剂在不同预处理入口温度、床层温升、体积空速、反应压力下预处理效果的优劣以及长周期稳定性。结果表明：在催化剂活性由低到高的级配方案中，得到的精制油中氮含量、硫含量和芳烃含量均低于活性由高到低级配的方案；建立反应温度对于2套催化剂活性级配方案预处理效果影响的预测模型，发现精制油性质实验值与预测值偏差极小，可靠性较强；催化剂按活性由低到高级配时的长周期稳定性优于单一预处理催化剂体系，因此催化剂按活性由低到高级配使用可有效延长加氢裂化装置的运转时间。

Experimental Study on Hydrocracking Pretreatment Catalysts in Activity Grading Sequence

Based on the reaction law of hydrocracking pretreatment catalysts in different partitions, two grading schemes of catalyst activity from low to high and from high to low were designed. Conventional vacuum gas oil (VGO) was used as raw material to comparatively investigate the pretreatment effect and long-term stability of the hydrocracking pretreatment catalysts in these two grading schemes under different reaction temperatures, bed temperature rises, volume space velocity and system pressures. The results show that the contents of nitrogen, sulfur and aromatics in refined oil obtained by the grading scheme of low to high catalyst activity are lower when compared with the results from the grading scheme of high to low catalyst activity; a prediction model where reaction temperature has an impact on the pretreatment effect of two sets of catalyst grading schemes is established, and it is found that the deviation between experimental value and predicted value of the refined oil is very small, while the reliability is strong, and the long-term stability of catalysts in the activity sequence from low to high is better than that of single pretreatment catalyst system, so that the grading scheme of catalysts in the activity sequence from low to high can effectively extend the operation time of hydrocracking unit.