INVESTIGADORES
SEDRAN Ulises Anselmo
congresos y reuniones científicas
Título:
A KINETIC APPROACH TO ACCESSIBILITY IN FCC CATALYSTS
Autor/es:
MARISA FALCO; EDISSON MORGADO; NORMA AMADEO; ULISES SEDRAN
Lugar:
Río de Janeiro, Brasil
Reunión:
Congreso; EMPROMER, 4th Mercosur Congress on Process Systems Engineering, 2nd Mercosur Congress on Chemical Engineering; 2005
Institución organizadora:
Universidad Federal de Río de Janeiro
Resumen:
The process of catalytic cracking of hydrocarbons plays a key role in the refineries that is
expanding in the near future as a consequence of two main factors: the production of petrochemical raw
materials and the conversion of resid feedstocks. The mass transfer process of large molecules through the
catalyst pores and the higher content of contaminants are particular problems of the heavier feedstocks. The
need for specific resid catalysts also requires new characterization techniques. While the Akzo Accesibility
Index AAI measures the dynamic diffusion of hydocarbon molecules and explains the performance of
commercial catalysts, the experimental conditions used are far from those of the commercial process. In order
to consider the simultaneous diffusion, adsorption and reaction of large molecules, a new approach was
developed based on the conversion of 1,3,5 tri-isopropylbenzene (TIPB) as a test reactant over commercial
catalysts and active matrices with different pore sizes. A fluidized bed, stirred batch laboratory Riser
Simulator reactor was used. Alumina matrix components of various mean pore sizes (64, 85 and 201 Å) were
tested at 500 ºC and catalyst to reactant ratio of 2.34 with reaction times between 8 and 25 seconds. Main
products were propylene, di-isopropylbenzene, isopropylbenzene, benzene and a TIPB isomer. As expected,
the activity of these aluminas is much lower than that observed on compound (zeolite plus matrix)
commercial catalysts. A simple kinetic model assuming first order reaction determined that the ranking of
reaction rates was r201 > r85 > r64, where the subscript refers to the mean pore size. Since the alumina
matrix samples differ mainly in their pore sizes, results can be associated to and considered representative of
the different accessibilities in the matrices.
matrix samples differ mainly in their pore sizes, results can be associated to and considered representative of
the different accessibilities in the matrices.
r201 > r85 > r64, where the subscript refers to the mean pore size. Since the alumina
matrix samples differ mainly in their pore sizes, results can be associated to and considered representative of
the different accessibilities in the matrices.