Optimal oxygen feeding policy to maximize the production of Maleic anhydride in unsteady state fixed bed catalytic reactors

Abstract

The effect of different oxygen feeding scenarios in a fixed bed reactor for the production of Maleic anhydride (MA) is studied. Two reactor configurations were examined. In the first configuration, a cross flow reactor (CFR) with 4 discrete feeding points is considered. Another configuration is the conventional packed-bed reactor (PBR) with a single feed. Nonlinear Model Predictive Controller (NLMPC) was used as optimal controller to operate the CFR in dynamic mode and to optimize the multiple feed dosages in order to enhance the MA yield. The simulation results indicated that different combinations of the four feed ratios can operate the reactor at the best value for the yield provided the first feeding point is kept as low as possible. For the packed bed reactor configuration, a single oxygen feed is considered and is optimized transiently by NLMPC. The simulation outcomes showed that the reactor performance in terms of the produced MA mole fraction can also be enhanced to the same magnitude obtained by CFR configuration. This improvement requires decreasing the oxygen ratio in the reactor single feed by 70%.

Keywords

• Maleic anhydride
• Cross flow reactor
• Feed staging
• Forced periodic feed
• Yield