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Solid-Liquid Heterogeneous Catalytic Reactions in a New Two-Impinging-Jets Reactor

Ghasemi, Mohammad | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41610 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Molaei Dehkordi, Asghar
  7. Abstract:
  8. In this work the transesterification reaction of waste cooking oil in the present of solid catalyst as a type of solid-liquid catalytic reaction, has been studied. For this purpose, two types of alkali solid catalysts were synthesized. CaO-ZrO2 and KOH/γ-Al2O3 catalysts were prepared by co-precipitation and impregnation method, respectively. These catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), BET surface area, and temperature programmed desorption of CO2 (TPD-CO2). The obtained results for the CaO-ZrO2 catalysts indicate that with increasing Ca/Zr atomic ratio, the activity of catalysts increases, but the stability of catalysts decreases. So as well, Ca/Zr atomic ratio equal to 0.5 was obtained as the optimal ratio of CaO-ZrO2 catalyst. Influences of Ca/Zr atomic ratio, catalyst amount, methanol/oil molar ratio, reaction time on the biodiesel yield were carefully studied. Under the suitable transesterification conditions at 65 °C (catalyst amount = 10 wt%, methanol/oil molar ratio = 30, reaction time = 2 h), the biodiesel yield equal to 91.2% can be achieved using CaO-ZrO2 catalyst with the Ca/Zr ratio of 0.5. The results of transesterification reaction over KOH/γ-Al2O3 catalysts indicate that as the loading amount of KOH increases, the activity and basicity of catalyst increases. Reaction parameters such as KOH loading (wt%), catalyst amount, methanol/oil molar ratio, and reaction time were optimized for the production of biodiesel. Under the suitable transesterification conditions at 65 °C (catalyst amount = 10 wt%, methanol/oil molar ratio = 15, reaction time = 3 h), the biodiesel yield equal to 86.23% can be achieved over KOH/γ-Al2O3 catalyst with the KOH loading of 25 wt%. KOH/γ-Al2O3 catalyst with the KOH loading of 25 wt% at the optimal conditions was used as a solid catalyst in a Two-Impinging Jets Reactor (TIJR) to produce biodiesel from waste cooking oil. The influences of various operating and design parameters such as jet Reynolds number, feed flow rate, internozzle distance, and the jet diameter on the performance capability of the TIJR were investigated. The obtained results indicate that with increasing of feed flow rate that passed through the reactor, or decreasing of the jet diameter, mixing intensity and thus biodiesel yield increase. The influence of increasing biodiesel yield is dramatically when increasing Re value results in fully suspended catalyst particles in the reaction chamber. These results carefully show the importance of type of mixing and mixing intensity in the transesterfication of waste cooking oil in the presence of solid catalyst
  9. Keywords:
  10. Esterification ; Biodiesel ; Solid Catalyst ; Calcume Oxide-Zirconium Oxide Catalyst ; Two-Impinging Jet Reactor ; Aluminum Dioxide/Potassium Hydroxide Catalyst

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