Abstract

GARCIA-SANCHEZ, Julieth; ARENAS-AGUILAR, Alejandra; CENDALES-SANCHEZ, Lüzeth  and  BALDOVINO-MEDRANO, Víctor. Design and implementation of a catalytic pyrolysis system for expanded polystyrene. Rev. ion [online]. 2024, vol.37, n.3, pp.57-71.  Epub Dec 09, 2024. ISSN 0120-100X.  https://doi.org/10.18273/revion.v37n3-2024005.

The objective of this research was to design and start-up a 316 stainless steel semi-batch reactor to use expanded polystyrene to obtain styrene through catalytic pyrolysis. A 1335 cm3 reactor was built consisting of a tubular vessel with a lateral vapor outlet, a heating oven, a coil-type condenser and a rotameter for feeding the carrier gas (N2). An industrial Fluidized Catalytic Cracking catalyst was used for the process. Within the methodology developed to carry out the catalytic tests, it stands out that: (i) the catalyst was mixed with the polystyrene by mechanical grinding. (ii) The temperature profiles of the reactor were determined, and the performance of the catalyst was compared with that observed in its absence. The efficiency of the process was evaluated in terms of the yield towards styrene and the purity of the liquid product. Finally, the best operating conditions were determined through a 32 factorial design using temperature (360, 430 and 500 °C) and bed height (4, 6 and 8 cm) as input variables. It was determined that the variables affect the purity of the liquid and the yield towards styrene in a similar way, but that the effect generated depends on the interaction between the two variables studied. The best operating conditions of the reactor obtained from the experimental design were 430 °C and 4 cm of bed, obtaining a yield of 0.74 g of styrene/g expanded polystyrene and 89 % purity.

Keywords : Expanded polystyrene; Catalytic pyrolysis; Styrene; FCC catalyst.

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