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Optimization of reaction rate parameters in modeling of heavy paraffins dehydrogenation

Vafajoo, L ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. Publisher: 2011
  3. Abstract:
  4. In the present study, a procedure was developed to determine the optimum reaction rate constants in generalized Arrhenius form and optimized through the Nelder-Mead method. For this purpose, a comprehensive mathematical model of a fixed bed reactor for dehydrogenation of heavy paraffins over Pt-Sn/Al 2O 3 catalyst was developed. Utilizing appropriate kinetic rate expressions for the main dehydrogenation reaction as well as side reactions and catalyst deactivation, a detailed model for the radial flow reactor was obtained. The reactor model composed of a set of partial differential equations (PDE), ordinary differential equations (ODE) as well as algebraic equations all of which were solved numerically to determine variations in components' concentrations in term of mole percents as a function of time and reactor radius. It was demonstrated that most significant variations observed at the entrance of the bed and the initial olefin production obtained was rather high. The aforementioned method utilized a direct-search optimization algorithm along with the numerical solution of the governing differential equations. The usefulness and validity of the method was demonstrated by comparing the predicted values of the kinetic constants using the proposed method with a series of experimental values reported in the literature for different systems
  5. Keywords:
  6. Catalyst ; Modeling ; Algebraic equations ; Arrhenius form ; Dehydrogenation reactions ; Detailed models ; Experimental values ; Fixed bed reactor ; Flow reactors ; Function of time ; Governing differential equations ; Kinetic constant ; Kinetic rates ; Mole percent ; Nelder-Mead ; Nelder-Mead methods ; Numerical solution ; Olefin production ; Optimization algorithms ; Optimum reaction ; Reaction rate parameters ; Reactor models ; Side reactions ; Catalyst deactivation ; Catalyst poisoning ; Chemical reactors ; Dehydrogenation ; Differentiation (calculus) ; Mathematical models ; Numerical methods ; Olefins ; Optimization ; Ordinary differential equations ; Partial differential equations ; Platinum ; Algorithms ; Catalysts ; Models ; Rate constants ; Paraffins
  7. Source: World Academy of Science, Engineering and Technology ; Volume 79 , 2011 , Pages 389-393 ; 2010376X (ISSN)
  8. URL: http://www.waset.org/publications/3901