Application of inverse problem and thermogravimetry to determine the kinetics of oil shale pyrolysis
Marco A. B. Zanoni, Henrique Massard, Marcio F. Martins and Sylvain Salvador
The kinetic parameters estimation is a very important step in building the reaction schemes commonly present in several fields of engineering. This step was reformulated as an optimization problem and it was minimized by using the Levenberg-Marquardt algorithm. The inverse technique was implemented with the help of thermogravimetric analysis. Thus, the Arrhenius parameters (pre-exponential factor, activation energy and reaction order) were estimated for a three-step mechanism proposed here to oil shale pyrolysis. The analyses of sensitivity and determinant have showed the feasibility of the estimation procedure. The estimated parameters for drying reaction was E2 = 46629 J mol-1, A2 = 58859 s-1 and n2 = 1.581; for pyrolysis reaction was E3 = 86051 J mol-1, A3 = 9728 s-1 and n3 = 1.302; and for decarbonation reaction was E4 = 251203 J mol-1, A4 = 2.138 × 1010 s-1 and n4 = 1.294. The maximum estimation error calculated was 2.6%.
Keywords: Kinetic parameters estimation, Inverse problem, Levenberg-Marquardt algorithm, TGA, Oil shale pyrolysis