Process, apparatus and compositions for recycle of cracking catalyst

Abstract

An improved catalytic process for heavy hydrocarbon conversion (usually but not necessarily in the presence of nickel and vanadium in the feedstock and on the catalyst) to produce lighter and selective molecular weight fractions. This process is specifically targeted as a means of retaining specialty high-valued, preferably microspherical additives (SHVA) which assist in attaining preferred conversion products such as gasoline, especially the recent gasolines meeting compositional requirements of 'Reformulated Fuel'. Selective magnetic retention of these high-cost specialty additives can be achieved by incorporating into them selective magnetic moieties, preferably manganese, the heavy rare earths and superparamagnetic iron. Selective retention is achieved by passing spent or regenerated catalyst containing small amounts of these SHVAs through a magnetic separator, and selectively recycling them back to the circulating catalyst.