催化裂解多产丙烯过程中的反应化学控制

在固定床微反实验装置上，选择正十六烷和大庆蜡油为原料，通过改变反应条件和催化剂类型研究了单、双分子反应对丙烯和干气生成的影响。结果表明，强化单分子反应有利于液化气中丙烯含量的提高，但干气产率也会同时增加；而一定程度上促进双分子反应，尤其是负氢离子转移反应的发生有助于抑制干气的生成，但程度太高时却不利于丙烯的生成。利用单、双分子反应的可控制性，采取措施合理调节反应过程中各自的比例和程度是降低现有催化裂解多产丙烯技术干气产率的有效途径。

REACTION CHEMISTRY CONTROL IN DEEP CATALYTIC CRACKING PROCESS FOR MAXIMIZING PROPYLENE YIELD

Based on analyzing the reaction chemistry of deep catalytic cracking, a basic idea for producing more propylene while reducing dry gas yield was proposed. The effect of monomolecular reactions and bimolecular reactions on the yields of propylene and dry gas was investigated in a fixed-bed micro-activity test unit using n-hexadecane and Daqing VGO as feedstocks respectively, under various reaction conditions and catalyst types. The results showed that enhancing monomolecular reactions could be favorable for increasing the propylene content in LPG, but the dry gas yield increased significantly. Promoting bimolecular reactions, mainly hydride transfer reactions, to some extent, would be helpful to inhibit the formation of dry gas; however, the high ratio of bimolecular reactions could cause the decrease of propylene yield. Hence, proper adjusting the ratio and/or the sequence of monomolecular reactions and bimolecular reactions might be an effective way for maximizing propylene yield and reducing dry gas yield simultaneously in deep catalytic cracking process.