A pilot plant study and 2-D dispersion-reactor model for a high-density riser reactor

The radial concentration profiles of reactant concentrations in a pilot pla nt high-density riser propylene ammoxidation reactor were sampled and analy zed and the extreme maldistribution of the profiles were found. A two-dimen sional dispersion-reactor model was proposed to simulate the selective oxid ization that taken place in the riser, which considered the influences of a xial and lateral gas mixing, the non-uniformity of radial solids concentrat ion and gas-velocity profiles on the reactor. The model can successfully pr edict the axial and radial profiles of concentrations sampled in the pilot plant. Simulation results indicate that the non-uniformity in radial cataly st concentration and gas-velocity distribution as well as insufficient late ral gas mixing result in a significant loss of selectivity and yield of acr ylonitrile. The scale-up effect and the interdependence of the reaction rat e, the non-uniformity of catalyst concentration and the requirement of gas mixing are discussed in details. (C) 2001 Elsevier Science Ltd. All rights reserved.