(56a) Heat of Cracking for Naphtha in Risers of Fcc Units

Abstract ? Experience in Fluidized Catalytic Cracking Units has shown that it is advantageous to introduce a naphtha stream in the FCC riser to produce light olefins like ethylene and propylene, high valuable petrochemical feedstocks. The reactions are mainly endothermic and the products are fuel gas, LPG, cracked naphtha, medium to heavy oil fractions, and coke deposited on the catalyst. To model this type of operation one needs to know the heat of reaction for the naphtha. One possible path is to combine operating data and analyses of the naphtha stream and products either from a pilot plant or from an industrial unit. The analyses include ASTM D-86 distillation, density, PIANIO chromatography and heats of combustion of the naphtha feed, cracked naphtha, and other products. These data are combined with heats of reaction for the pure compounds and operating data in a computer routine which performs the heat balance. This work presents results of heats of reaction for the cracking of naphtha obtained in a FCC pilot plant of our Research Center.