Tesis
Síntese e caracterização de zeólitas ZSM-5 por diferentes rotas e seu emprego na produção de olefinas leves a partir de etanol
Fecha
2014-08-12Registro en:
SALBEGO, Paulo Roberto dos Santos. Synthesis and characterization of ZSM-5 zeolites by different routes and its use in the conversion of ethanol to olefins. 2014. 132 f. Dissertação (Mestrado em Engenharia) - Universidade Federal de Santa Maria, Santa Maria, 2014.
Autor
Salbego, Paulo Roberto dos Santos
Institución
Resumen
This work aims the synthesis and study of ZSM-5 catalysts for the conversion of
ethanol to light olefins, especially, using an alternative and inexpensive route. The
ethanol emerges as a renewable source for the production of olefins and the ZSM-5
catalyst has important characteristics for this type of reaction such as acidity, surface
area and particle size. The synthesis was carried out in hydrothermal treatment at 170
°C. Were performed two conventional synthesis with templates, using n-Butylamine
and tetrapropylammonium hydroxide (TPAOH), and an third and alternative route using
a nucleating gel. The catalyst characterization was performed using several techniques
(XRD, BET, XRF, SEM and TGA) and was observed the formation of the ZSM-5
structure in all the synthesis methods. The catalysts were evaluated in the ethanol to
olefins (ETO) reaction, and was evaluated the influence of the reaction temperature
(250 to 450 °C) and SAR (SiO2/Al2O2 ratio) in the selectivity for olefins. The products
analyses were made with a gas chromatograph with a FID-type detector. The ethylene
yield was above to 80 % for all catalysts, and some above 90 %. Lower SAR values
provided higher yields for propylene, around to 9 %. The temperature, SAR and
template used in the synthesis influenced in the selectivity. In addition, was evaluated
the influence of the catalyst mass, dilution and also its modification with different
metals. When the mass was increase, the yield for propylene increased. The catalyst
dilution with common sand provided, in some concentrations, greater propylene
formation. The nucleating gel method showed to be a viable alternative for ZSM-5
synthesis and its use in the ETO reaction.