ZnHZSM－5芳构化催化剂积炭影响因素的研究

本文利用ＮＨ３－ＴＰＤ，ＩＲ，Ｃａｈｎ－２０００电天平及微型反应装置，考察了ＺｎＨＺＳＭ－５沸石催化剂在劳构化反应中的积炭行为．结果表明，催化剂的表面酸强度和性质、酸中心密度及晶粒大小都对结炭有显著的影响．加入Ｐｔ４＋可抑制积炭．外表面中毒则加速炭的生成．积炭分为两个阶段进行，积炭初始主要发生在沸石催化剂晶粒内部．预结炭并钝化炭表面可提高ＺｎＨＺＳＭ－５催化剂的稳定性．

THE COKE DEPOSITION ON ZnHZSM-5 ZEOLITE CATALYST

he coke deposition on ZnHZSM-5 zeolite catalyst for aromatization has been investigated by TPDA, IR, TGA. The results show thatthe strength, the type (B acid or L acid) and the density of the surfaceacid of catalyst have obvious effect on coke deposition. The addition ofPt4+ into ZnHZSM-5 led to a decrease in the coke deposition rate. Thecoke deposited mainly on the inner surface of catalyst particles. Theparticle size of catalyst and the diffusion of products displayed strong effect on coke deposition. The poisoning of the outer surface of catalystraised the rate of coke deposition. The coke deposition process on ZnHZSM-5 catalyst for aromatization might be divided into two stages, i.e. first stage of carboneous species formation mainly on the strong acidsites and then the growth of coke particle size. Pre-coking and passivating the coke surface could improve the stability of ZnHZSM-5 catalyst.