Effect of partial substitution of Ca in LaMnO on coal catalytic combustion.

Coal combustion catalysts of mesoporous perovskite-type LaCaMnO were prepared by sol-gel method. The resulting powder was characterized by scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction, dynamic light scattering and differential scanning calorimetry. After partially substituting La with Ca in LaMnO, Ca was found to occupy parts of La-site. As the substitution rate of Ca increased, the catalyst particle size distribution decreased and the pore size distribution of catalysts increased. Thermogravimetric measurements and combustion of coal in the presence of the LaCaMnO catalysis indicated that the presence of catalysts reduced the temperature for onset of coal combustion and increased the combustion rate. In fact, the addition of 1 % LaCaMnO to coal made the combustion point decrease by 41.5 K compared with coal alone. On the other hand, addition of 1 % LaCaMnO made the combustion rate increase by 22.2 % compared with combustion rate of organic coal. [ABSTRACT FROM AUTHOR]