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

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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.