MACROKINETIC MODELS OF THERMAL DECOMPOSITION OF DOLOMITE FOR ENGINEERING CALCULATIONS

The authors have formulated macrokinetic models of thermal decomposition of dolomite that vary in the number of the considered effective chemical processes, the mechanism of evacuation of carbon dioxide, the dependent/ independent behavior of chemical reactions, and the number of parameters. The models were used as basic ones for approximating experimental data on the thermal decomposition of dolomite. The experiments on dolomite decomposition were conducted with a Q-1000 derivatograph of the MOM Company at a rate of heating of the samples of 5, 10, and 20 K/min, and also in a quasi-thermal regime. Based on the array of experimental data, the authors have determined the parameters of dolomite-decomposition models. An analysis of the adequacy of the models to the experimental data has been made. It has been shown that taking account of the series character of decomposition of dolomite and calcite in two reactions does not result in the improvement of the approximation accuracy of experimental data. The approximation accuracy of experimental data corresponds to the accuracy of approximated experimental data, with the models with 5 to 7 parameters exhibiting no noticeable advantages over 3- and 4-parametric models. However, the model with 2 parameters shows much lower accuracy. The models whose parameters were set according to the dynamic dolomite-decomposition data satisfactorily describe quasi-isothermal decomposition regime too; however, in modeling the latter, it is expedient to set the model′s parameters according to the data of quasi-isothermal experiments.
   
Author:  K. V. Dobrego, I. A. Koznacheev, E. S. Shmelev, M. V. Mal′ko, and S. V. Vasilevich
Keywords:  dolomite, kinetics, thermogravimetry, modeling