NOx reduction in a fluidized bed reactor with Fe/ZSM-5 catalyst and propylene as reductant

Abstract

The performance of a fluidized bed catalytic reactor was investigated for NOx reduction using a Fe/ZSM-5 catalyst and propylene as the reducing agent. The effects of inlet NOx concentration, propylene to NO x molar ratio, flue gas oxygen concentration and fluidizing gas velocity on NOx conversion were studied using simulated flue gases. The results showed that the NOx conversion decreased with decreasing the inlet NOx concentration, and propylene to NOx molar ratio. The increase in flue gas oxygen concentration also imposed a significant negative impact. As the flue gas oxygen concentration increased, NOx reduction decreased while propylene conversion increased at a given propylene to NOx molar ratio, due to the oxidation of propylene in the presence of high oxygen concentration. The increase in fluidization gas velocity reduced the contact time between reactant and the catalyst particles due to the increased bubble size and bubble rise velocity. As a result, the NOx reduction decreased as the gas velocity increased.