Reverse-flow reactor for a selective oxidation process

The simulation of a reverse-flow operation of a fixed-bed catalytic reactor , where the highly exothermal partial oxidation of o-xylene to phthalic anh ydride is processed, is accomplished by using a heterogeneous one-dimension al model, which accounts for mass transport by diffusion and convection ins ide large-pore catalytic particles. The dynamic behaviour of the reactor is analysed by varying the inlet conditions and the switching period. This wo rk. points out the benefits that can arise from the use of the reverse-flow operation, namely the decrease of the hot-spot temperature and the more fa vourable temperature distribution along the bed. In spite of the lower temp erature profiles, the final conversion, as well as selectivity and yield of phthalic anhydride are not. significantly affected. The results predicted by the heterogeneous model with intraparticle convection and diffusion, HT, , model, are compared with those obtained when diffusion is the only transp ort mechanism inside the catalyst, HT, model. A comparison with the simple pseudo-homogeneous model, PH, is also achieved. (C) 1999 Elsevier Science L td. All rights reserved.