Dual riser catalytic cracker for increased light olefin yield

  • US 9,238,600 B2
  • Filed: 12/14/2011
  • Issued: 01/19/2016
  • Est. Priority Date: 12/14/2011
  • Status: Active Grant
First Claim
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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.

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