Catalytic cracking process with recirculation of an olefinic cut extracted upstream of the gas separation section to maximize propylene production

摘要

Process for the production of gasoline and the simultaneous production of propylene by means of a catalytic cracking unit that has at least one main reactor (1) that operates in an upward flow (called "rising pipe") or downward (called "down pipe") and which treats a conventional heavy load (CH1), and optionally a secondary riser (2) that operates under more severe conditions than the main riser (1) and that treats a lighter charge (CH2), a procedure in which it is also discussed of the main charge (CH1) and optionally the lightest charge (CH2), a charge made up of olefinic molecules mainly of C4, C5 and C6, said olefinic charge being extracted at the height of the intermediate stage of the wet gas compressor that is part of the gas treatment section (SRG) associated with the FCC unit and that constitutes the stream of the intermediate stage (22).