Numerical Approach in Determination of Thermophysical Material Properties in Decomposition of Lumpy Dolomite Particles (original) (raw)

We report on the decomposition of cylindrical dolomite (CaMg(CO 3) 2) particles through the two steps decomposition scheme with the objective of determining the thermophysical properties of the decomposition product in each step. Samples of size 24 and 32 mm were decomposed in a tube furnace at constant ambient temperature and at atmospheric pressure. By means of weighing and simultaneous temperature measurement, the decomposition behaviour is studied. Obtained decomposition behaviour are remarkably similar to that reported for pure magnesite in step 1 and pure limestone in step 2. Thermophysical properties of MgO•CaCO 3 and MgO•CaO at different temperatures were estimated by numerically solving the heat and mass transfer equations describing the process, based on the shrinking core model, using the finite difference approach. The reaction coefficient and thermal conductivity of MgO•CaCO 3 vary from 0.0040 to 0.0085 m/s and 0.79 to 0.92 W/m.K respectively and the permeability is approximately 1 x 10-12 m 2. The reaction coefficient and pore diffusivity of MgO•CaO are in the range of 0.013-0.014 m/s and 1.7 x 10-5-3.0 x 10-5 m 2 /s and the thermal conductivity is approximately 0.8 W/m.K.