CATALYST ARRANGEMENT WITH OPTIMIZED VOID FRACTION FOR THE PRODUCTION OF PHTHALIC ACID ANHYDRIDE

摘要

The invention relates to a catalyst arrangement for the production of phthalic anhydride by gas phase oxidation of aromatic hydrocarbons, comprising a reactor having a gas inlet side for a reactant gas and a gas outlet side for a product gas, and a first catalyst layer that consists of catalyst bodies and at least a second catalyst layer that consists of catalyst bodies, the first catalyst layer being arranged on the gas inlet side and the second catalyst layer being arranged downstream of the first catalyst layer in the gas flow direction, and the length of the first catalyst layer being shorter in the gas flow direction than the length of the second catalyst layer in the gas flow direction, characterized in that the first catalyst layer has a higher void fraction than the second catalyst layer.