Abstract

Limestone calcination reaction seems to be a very simple and straight-forward reaction. However, there are numerous critical variables that exert profound effect on lime burning operations. The factors and variables that affect the burning of limestones must be considered in the selection, design and optimization of the calcininig equipment. Limestone burning in a vertical kiln often presents complex problems which can be solved from the conception by consideration of the prevailing factors that determine the progress of calcinations reactions. The evaluation of the influence of these factors on the progress of the burning of Jakura limestone in a vertical shaft lime kiln is the thrust of this work. Basic kinetic parameters such as: diffusivity, mass transfer coefficient, conductivity, heat transfer coefficient, convective parameter, and diffusive parameter of the lime layer of the calcining limestone particle were obtained from the calcinations tests. Computer programs were developed to evaluate the effects of these factors for typical burning conditions. The shrinking core kinetic model of the reaction limited by heat and mass transfer was employed in the evaluation. The effects of chemical kinetics, stone size and gradation, calcination tempera ture, calcination time, effect of pressure and flow conditions in the kiln were evaluated.

Key words: Limestone, calcination, vertical shaft lime kiln, shrinking core kinetics, calcining equipment.