Modeling the dynamic behavior of industrial fixed bed reactors for the manufacture of maleic anhydride

Abstract

The industrially important selective oxidation of n-butane over vanadium phosphorus oxide catalysts in fixed bed reactors is affected by phosphorus induced dynamic changes of the catalyst activity. An economic process management therefore requires an adequate control of the operating conditions including the precise addition of a phosphorus containing compound in the ppm range. In a previous work (Lesser et al., 2016) we experimentally investigated these phenomena and related our findings to the diverse literature discussions abound reaction mechanism and active sites. Based on our conclusions, the present work provides a detailed model for the phosphorus dynamics which is connected to a two-dimensional heterogeneous reactor model. The model is able to describe the reactor behavior properly over 500h time on stream including many variations of the operating conditions. The dynamically changing activity profiles reflect the evolution of temperature profiles and product compositions with only minor deviations.