Dual riser catalytic cracker for increased light olefin yield

摘要

A process for improving the yield of ethylene and propylene from a light naphtha feedstock includes obtaining light naphtha feedstock from a primary cracking zone having a cracking catalyst. The light naphtha feedstock is contacted with an olefin catalyst in an olefin producing zone to produce an ethylene- and propylene-rich stream. After reacting with the olefin catalyst, the ethylene- and propylene-rich stream is separated from the olefin catalyst from in a separator zone. At least a portion of the olefin catalyst is regenerated by combusting coke deposited on a surface of the olefin catalyst in an oxygen-containing environment, and at least a portion of the olefin catalyst is heated. These portions could be the same one or they could be different. In some embodiments, at least a portion of the olefin catalyst could be neither regenerated nor heated. The olefin catalyst is returned to the olefin producing zone.

主权项

1. A process for improving the yield of ethylene and propylene from a light naphtha feedstock, comprising:
obtaining light naphtha feedstock from a primary cracking zone comprising a cracking catalyst; contacting the light naphtha feedstock with an olefin catalyst in an olefin producing zone to produce an ethylene- and propylene-rich stream; separating the olefin catalyst from the ethylene- and propylene-rich stream in a separator zone; regenerating at least a portion of the olefin catalyst by combusting coke deposited on a surface of the olefin catalyst in an oxygen-containing environment; directly heating at least a portion of the olefin catalyst by direct heat exchange outside of a reactor of the olefin producing zone with a stream of hot combustion gas, wherein at least a portion of the hot combustion gas is flue gas from a catalyst regenerator for the cracking catalyst; and returning the olefin catalyst to the olefin producing zone.