Olefin production utilizing whole crude oil/condensate feedstock with a partitioned vaporization unit

In a method for operating an olefin production plant that employs a pyrolysis furnace to severely thermally crack hydrocarbon containing material for subsequent processing of the thus cracked product in said plant which method of plant operation includes 1) providing at least one of whole crude oil and natural gas condensate as said hydrocarbon containing material, 2) submitting said whole crude/condensate feed to a vaporization zone wherein said feed is substantially vaporized, and 3) feeding said substantially vaporized feed from said vaporization zone to said pyrolysis furnace, said vaporization zone having an inlet end and outlet end and performing at least first and second separate vaporization steps wherein A) in said first step gaseous materials present and formed in said first step are removed for transport to said pyrolysis furnace, leaving an essentially liquid remainder, and B) in said second step said essentially liquid remainder is subjected to more stringent conditions to vaporize a substantial part of said liquid remainder for transport to said pyrolysis furnace, the improvement comprising in said second step providing a physically partitioned vaporization chamber having first and second sides, each side having opposing inlet and outlet ends, said inlet and said outlet ends being in vapor communication with one another, feeding said essentially liquid remainder to said inlet end of said first side of said partitioned vaporization chamber, feeding a hydrocarbon stream having a boiling range of from about 380 to about 700 F to said inlet end of said second side of said partitioned vaporization chamber, and removing from said second side of said partitioned vaporization chamber a hydrocarbon stream having a boiling range of from about 100 to about 700 F.