Influence of distributed reactant injection on the performance of fluidized bed reactor of oxidative coupling of methane (OCM) was investigated by means of reactor modeling and simulation. A two-phase hydrodynamic model was coupled with a comprehensive kinetic model of OCM over Mn/Na2WO4/SiO2 catalyst to predict the performance of the reactor. In the stage-wise feeding, flow of air is divided into few portions. One portion is introduced to the fluidized bed through the distributor at the bottom and other portions are injected inside the bed. It was shown that at low temperatures C2 yield in the stage-wise feeding configuration is higher than the conventional co-feeding whereas at high temperatures, yield of products in stage-wise feeding is lower than co-feeding. Therefore, optimum operating temperature of the reactor can be decreased from 800 C in co-feeding to 750 C with two secondary air injections, while keeping the same conversion and yield. Moreover, it was shown that oxygen distribution along the bed decreases making the reactor performance to be less sensitive to change in temperature. In general, when applying stage-wise feeding configuration, the reactor can operate at lower temperature, effect of temperature change on the performance of the reactor would be less and removing the heat of reaction becomes more effective when compared to co-feeding configuration. These results in widening the safe range of operating conditions, providing a more stable process with better temperature control and reducing other problems of high temperature processes in the OCM fluidized bed reactor.
- fluidized bed; stage-wise feeding; OCM; reactor modeling
Available at: http://works.bepress.com/navid_mostoufi/40/