Catalytic cracking of hydrocarbons

摘要

Emission of noxious nitrogen oxides with the flue gas from the regenerator of a fluid catalytic cracking plant are reduced by incorporating into the circulating inventory of cracking catalyst separate additive particles that contain a copper-loaded zeolite material having a characteristic structure with a defined X-ray diffraction pattern. The preferred material of this type is zeolite MCM-22. The copper may be exchanged onto the zeolite or impregnated into the catalyst. In addition, the catalyst may include titanium or zirconium to provide stability and further improvements in stability may be obtained with the addition of rareearth metal cations, especially cerium or yttrium. NOX and CO emissions from the regenerator are reduced, and the gasoline produced in the unit may have an improved octane number.