INVESTIGATION OF COKE EXTRACTION FROM ZEOLITE-HY UNDER SUPERCRITICAL AND NEAR-CRITICAL CONDITIONS

In-situ regeneration of deactivated catalysts by dissolving coke or co ke precursors with supercritical reaction fluids is of important econo mical significance. Investigations of coke extraction on zeolite-HY we re performed in a gradientless reactor under supercritical and near-cr itical conditions with ethylbenzene disproportionation as a test react ion and n-butane or n-pentane as inert. Experimental results illustrat e the large ability of coke extraction under supercritical conditions. The influences of the experimental conditions on the ethylbenzene dis proportionation and the coke extraction are discussed. Under appropria te supercritical conditions the coking and the coke extraction can rea ch an equilibrium, so that no further deactivation of the catalyst was observed. Several regularities about coke extraction on the surface o f the catalyst are proposed.