Experimental and modeling analysis of NO reduction by CO for a FCC regeneration process

The catalyzed NO–CO–O2 reaction system was studied, where the catalyst was either a FCC catalyst or a Pt-based catalyst. With the Re/USY FCC catalyst, NO was both reduced directly to N2 and converted first to NO2 and then reduced to N2 by CO. O2 was an inhibiter of the reduction of NO by CO, and the CO–NO reaction did not occur until the O2 concentration was less than 0.1%. The reduction of NO by CO was enhanced by the Pt/SAPO-34 catalyst, even at lower temperatures, because O2 was consumed by CO in the presence of this catalyst. The reaction mechanism and effect of O2 were discussed. The modeling of the NO–CO–O2 reaction system with a reduced mechanism was in good agreement with the experimental results in a wide range of temperatures. NO conversion was affected by the molar ratio of O2/CO. Inhibition of NO reduction by CO due to O2 addition was attributed to the decrease of CO(s) and increase of O(s).

► NO–CO–O2 reaction system with a catalyst, a FCC catalyst or a Pt-based catalyst were studied.
► The complex NO–CO–O2 reaction system were modeled.
► O2 inhibition mechanism on reduction of NO by CO were investigated.
► NO conversion was affected by the mole ratio of O2/CO.
► A reduced mechanism gave good agreement with the experimental results.