Removal of NOx in a Catalytic Cracker

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United States Patent 7,918,991 to Michael Ziebarth and two others is entitled “Compositions and processes for reducing NOx emissions during fluid catalytic cracking.” The patent teaches several compositions that can be combined with Y-type zeolites to reduce NOx emissions. The NOx reducing zeolites have pore sizes in the 2-7 Angstrom range, are SiO2/Al2O3 compositions and in one version of the invention are stabilized with zinc ions. An alumina binder is also used in certain embodiments of the invention. According to the invention disclosure, mixed catalysts of this variety are more effective at removing the NOx emissions associated with catalyst regeneration with little or no detriment to fluid catalytic cracking unit performance.