Abstract

MAVHENGERE, P.; VITTEE, T.; WAGNER, N.J.  and  KAUCHALI, S.. An algorithm for determining kinetic parameters for the dissociation of complex solid fuels. J. S. Afr. Inst. Min. Metall. [online]. 2016, vol.116, n.1, pp.55-63. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2016/v116n1a9.

An established distributed activation energy model (DAEM)-based algorithm for the dissociation of complex fuels obeying linear kinetics was modified to determine the kinetic parameters of materials reacting in a CO₂ gas stream by incorporating the random pore reaction model (RPM). The algorithm was adapted to the RPM and was able to derive the activation energy, E, the grouped pre-exponential factor, A, and the number of reactions occurring in the thermal conversion process. Furthermore, the mass fraction associated with each unique reaction was obtained. The ability to accurately determine multiple reactions and changes in the kinetic parameters during the reaction distinguishes the algorithm as a unique and robust method for determining kinetic parameters for the pyrolysis of complex fuels. The novelty in this research was the adaptation of the RPM and other reaction models to the DAEM algorithm, and hence to other conversion processes. The algorithm was tested on simulated conversion data and experimental data from thermogravimetic analysis of the dissociation of a South African coal char and a 50:50 (wt%) coal-biomass blend char under CO₂ atmosphere. The specific mass fraction of the reactive material dissociating under a particular set of kinetic parameters was determined, and all sets of data were successfully modelled to high accuracy.

Keywords : distributed activation energy model; random pore reaction model; kinetics; gasification.

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