Optimal temperature policy in a riser reactor

The nature of the optimal axial temperature distribution in a riser reactor to maximise the yield of the intermediate B, in the reaction sequence A→B→C was investigated by way of the selective oxidation of naphthalene to phthalic anhydride. For this case, imposition of an axial profile could not improve the yield over that obtainable by operating at the optimum isothermal temperature. This result appears to be general, and suggests that optimal yields could be obtained by operation at the optimum isothermal temperature, which should prove easier to implement in practice than a specified temperature distribution.