Investigation of coke extraction from zeolite‐HY under supercritical and near‐critical conditions

Abstract

Abstract In‐situ regeneration of deactivated catalysts by dissolving coke or coke precursors with supercritical reaction fluids is of important economical significance. Investigations of coke extraction on zeolite‐HY were performed in a gradientless reactor under supercritical and near‐critical conditions with ethylbenzene disproportionation as a test reaction and n ‐butane or n ‐pentane as inert. Experimental results illustrate the large ability of coke extraction under supercritical conditions. The influences of the experimental conditions on the ethylbenzene disproportionation and the coke extraction are discussed. Under appropriate supercritical conditions the coking and the coke extraction can reach an equilibrium, so that no further deactivation of the catalyst was observed. Several regularities about coke extraction on the surface of the catalyst are proposed.