oxidation

An appropriate simplified model has been developed to describe the steady-state and dynamic behaviour of a fixed-bed catalytic reactor for the oxidation of o-xylene to phthalic anhydride. Predictions have been compared with experiments in a single-tube reactor of industrial dimen-sions, using measurements of temperature and composition at 26 axial positions. Experiments point out the existence of regions of moderate or high sensitivity to changes in operating condi-tions; the model predicts the same behaviour. However, variations in catalyst activity as a function of both time and position can lead to some ambiguity in the interpretation of results. Notation C concentration cp, cp, specific heat capacity of gas and solid, respectively Z3 ~ radial dispersion coefficient h~, reactor wall heat transfer coefficient ke effective conductivity of catalyst bed r radial position rT reactor tube radius R rate of reaction T ’ reactor temperature T, ~ reactor wall temperature t time u linear velocity of gas z axial position AH heat of reaction p, ps density of gas and solid, respectively Subscripts i ith component o feed (inlet) conditions ss steady-state condition