Patent ID: 7419584

Claim:
An apparatus for cracking a hydrocarbon feedstock containing resid, said apparatus comprising: (a) a heating zone for heating said hydrocarbon feedstock to provide heated hydrocarbon feedstock; (b) a mixing zone for mixing a primary dilution steam stream with said heated hydrocarbon feedstock to provide a heated two-phase stratified open channel flow mixture stream; (c) a vapor/liquid separation zone for treating vapor/liquid mixture streams of hydrocarbons and steam, said zone comprising: (i) a substantially cylindrical vertical drum having an upper cap section, a middle section comprising a circular wall, and a lower cap section; (ii) an overhead vapor outlet attached to said upper cap section; (iii) at least one substantially tangentially positioned inlet in the wall of said middle section for introducing said flow mixture stream along said wall under flashing conditions where the flow mixture stream undergoes an initial flashing to form A) a vapor phase at its dew point which contains a lesser portion of coke precursors, and B) a liquid phase which contains a greater portion of coke precursors; (iv) a partial condenser for contacting the vapor phase within said drum for at least partially condensing at least some of said lesser portion of coke precursors, which adds to said liquid phase, said condensing providing a vapor phase of reduced coke precursors content; (v) a drum overhead outlet for removing the vapor phase of reduced precursors content as overhead; (vi) a drum liquid outlet for removing said liquid phase as bottoms from said drum; and (vii) a substantially concentrically positioned, substantially cylindrical boot of less diameter than said middle section, said boot communicating with said lower cap section, and further comprising an inlet for quench oil and a liquid outlet at its lower end; (d) a pyrolysis furnace comprising a convection section, and a radiant section for cracking the vapor phase from the overhead vapor outlet to produce an effluent comprising olefins; (e) a means for quenching the effluent; and (f) a recovery train for recovering cracked product from the quenched effluent.