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Fischer-tropsch synthesis: development of kinetic expression for a sol-gel Fe-Ni/Al 2O 3 catalyst

Sarkari, M ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1016/j.fuproc.2012.01.008
  3. Publisher: 2012
  4. Abstract:
  5. In this experimental study, a kinetic model has been developed for Fischer-Tropsch synthesis reactions by using sol-gel technique and Fe/Ni/Al 2O 3 as the catalyst (40% Fe/60% Ni/40 wt.%Al 2O 3) in a differential fixed-bed micro reactor assuming no internal or external diffusion. Operating conditions of the reactor were as follows: total pressure 1-12 atm; Temperature 220-260 °C; H 2/CO feed ratio 1.5-2; gas hourly space velocity 2100-7000 cm 3(STP)/h/ g cat and conversions of 6-37% of hydrogen and 7-21% of carbon monoxide. Mass transfer limitations were investigated by changing synthesis gas velocity in reactors which differ in size. Based on the hypothesis that water inhibits the intrinsic Fischer-Tropsch (FT) reaction rate in the iron-FT synthesis, all rate expressions in this study were in inverse ratio to number of vacant sites and CO and water content. The obtained data in this study were checked using "complete form of Langmuir-Hinshelwood-Hougan-Watson (LHHW)" which has been proposed by Van der Laan and Botes. The kinetic parameters were determined using Levenberg-Marquardt (LM) method. The activation energy and heat of adsorption of CO and water were 103.81, - 56.82 and - 25.62 kJ/mol, respectively
  6. Keywords:
  7. Levenberg-Marquardt (LM) method ; Experimental studies ; Feed ratios ; Fischer Tropsch ; Fischer-Tropsch synthesis reaction ; Fixed-bed ; Gas hourly space velocities ; Heat of adsorption ; Inverse ratio ; Kinetic expression ; Kinetic models ; Levenberg-Marquardt ; Mass transfer limitation ; Micro reactor ; Operating condition ; Rate expression ; Sol-gel technique ; Total pressure ; Vacant sites ; Activation energy ; Adsorption ; Carbon monoxide ; Catalysts ; Enzyme kinetics ; Hydrogen ; Kinetics ; Reaction rates ; Sol-gel process ; Sol-gels ; Synthesis gas ; Fischer-Tropsch synthesis
  8. Source: Fuel Processing Technology ; Volume 97 , May , 2012 , Pages 130-139 ; 03783820 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0378382012000227