Patent ID: 7727486

Claim:
An apparatus for processing streams from a fluid catalytic cracking unit comprising: a fluid catalytic cracking reactor for contacting cracking catalyst with a hydrocarbon feed stream to crack the hydrocarbons to gaseous product hydrocarbons having lower molecular weight and deposit coke on the catalyst to provide coked catalyst; a product outlet for discharging said gaseous product hydrocarbons from said reactor; a regenerator for combusting coke from said coked catalyst by contact with oxygen; a flue gas outlet for discharging flue gas from said regenerator; a product recovery section in downstream communication with said product outlet, said product recovery section for separating said gaseous products into a plurality of product streams including a selected product stream; an expander in downstream communication with a selected product line in downstream communication with said product recovery section; said regenerator being in downstream communication with said product recovery section; and a preheater in downstream communication with said product recovery section and said expander, said regenerator is in downstream communication with said preheater.