Patent ID: 7597796

Claim:
An apparatus for catalytically cracking a conventional feed and a secondary feed comprising a principal riser (B) defining a conventional reaction zone; a transfer line (A) for the principal riser (B) supplying fresh catalyst or catalyst from a regeneration unit; means (1) for injecting conventional feed into the principal riser (B); means for injecting atomization vapor into the principal riser (B); said apparatus further comprising: at least one secondary riser (C) parallel to the principal riser (B), the lower end of which is open to the bottom portion of the principal riser (B) and the upper end of which is open to the top portion of the principal riser (B), said secondary riser(s) being external to the principal riser (B) and defining a secondary reaction zone for cracking of a secondary feed; and means (3) for injecting a secondary feed into the secondary riser or risers (C); means for controlling the cracking conditions for the secondary feed.