Patent ID: 7906015

Claim:
A process for reducing the content of gas phase reduced nitrogen species in the off gas derived from a regeneration zone of a fluid catalytic cracking unit (FCCU), said process comprising (a) circulating an inventory of catalytic cracking catalyst and a gas phase reduced nitrogen species oxidation catalyst/additive composition throughout an FCCU having a regeneration zone operated under a partial combustion mode or an incomplete combustion mode and having a dilute phase, during a fluid catalytic cracking process, wherein gas phase reduced nitrogen species are contained in an off gas released from the FCCU regeneration zone, and wherein the oxidative catalyst/additive composition has the ability to oxidize CO under fluid catalytic cracking conditions and simultaneously oxidize gas phase reduced nitrogen species in the off gas to molecular nitrogen under partial or incomplete burn catalytic cracking conditions, the FCCU regeneration zone being capable of afterburn in the dilute phase, said oxidative catalyst/additive composition being used in an amount which is at least 0.01 wt % of the cracking catalyst inventory and which is less than an amount sufficient to prevent afterburn in the dilute phase of the FCCU, and said oxidative catalyst/additive composition having a mean particle size of about 50 to about 200 μm, (b) contacting in the FCCU regeneration zone the gas phase reduced nitrogen species with the gas phase reduced nitrogen species oxidative catalyst/additive composition; and (c) reducing the content of gas phase reduced nitrogen species in the FCCU regeneration zone off gas relative to the content of gas phase reduced nitrogen species in the off gas absent the presence of the oxidative catalyst/additive composition.