An Experimental Investigation of the Reactivation of Coked Catalysts under Supercritical Fluid Conditions

本项目的目的是通过实验研究超临界流体（SCF）溶剂对焦化催化剂的再活化。具体来说，本文讨论了以下几点：(a) SCF溶剂在从多孔催化剂中提取形成焦炭的化合物方面的效果如何？(b)是否有可能通过定期用SCF溶剂提取形成焦炭的化合物来保持催化剂活性，从而防止焦炭在催化剂中积聚？这些问题通过对铂/ γ -铝催化的1-己烯异构化的系统实验研究来解决，这是一个通过焦化同时失活的反应系统。反应在高压釜反应器中进行，而催化剂再活化在高压平衡池中进行。SCF采用的溶剂是超临界二氧化碳。除了在原位进行催化剂再活化的可能性之外，与传统工艺相比，所提出的再活化方案还可以在相对较低的温度下操作。因此，任何热失活的催化剂和载体是最小的。这个项目的成功完成将带来设计新颖、节能的催化剂再活化方案的潜力。此外，本研究的信息也适用于理解SCF从固体煤或任何多孔基质中提取低分子量组分。

The objective of this project is to experimentally investigate the reactivation of coked catalysts using supercritical fluid (SCF) solvents. Specifically, the following points are addressed: (a) How effective is an SCF solvent in the extraction of coke forming compounds from a porous catalyst? (b) Is it possible to maintain catalyst activity in situ by periodically extracting the coke-forming compounds with an SCF solvent, thus preventing any accumulation of coke in the catalyst? These questions are addressed through systematic experimental investigations of the platinum/gamma-alumina-catalyzed isomerization of 1-hexene -- a reaction system that undergoes simultaneous deactivation by coking. The reaction is carried out in an autoclave reactor, while catalyst reactivation is performed in a high-pressure equilibrium cell. The SCF solvent employed is supercritical carbon dioxide. Besides the possibility of performing catalyst reactivation in situ, the proposed reactivation scheme also operates at relatively mild temperatures as compared to conventional processing. Hence any thermal deactivation of the catalyst and support is minimized. Successful completion of this project should bring out the potential for devising novel, energy- efficient catalyst reactivation schemes. Besides, information from this research also has application in the understanding of SCF extraction of lower molecular-weight constituents from solid coal or any porous matrix in general.