Effect of Pine Bark Combustion Temperature on Content of Major, Minor, and Trace Elements in Ashes: Experimental Study and Thermodynamic Equilibrium Calculations

Abstract

Wood biomass is widely used as fuel in the so-called green power units producing heat and electricity. Wood biomass, like other solid fuels, contains many elements, most of which are found in trace amounts. The bark of Mediterranean pine cleaned of wood was chosen for the study presented in this paper. Thirty-five elements, of which 19 are trace elements (TEs), were identified in the pine bark. An experimental study on the ground pine bark burning at temperatures 650°C, 750°C, 850°C, and 950°C was conducted on a laboratory scale. Ashes formed from combustion at particular temperatures were analyzed. Experimental results and calculations of thermodynamic equilibrium were compiled in the form of a series of small graphs for major elements, minor ones, and TEs present in ashes, which allows quick evaluation of the results of the study. The consequence of an increase in the combustion temperature was the reduction of the content of K, S, Cu, and Pb in ash. TEs with the highest retention in ashes included Co, V, Cr, Sr, Ba, and Ni. The thermodynamic equilibrium calculations performed in the FactSage software version 6.3 made it possible to predict the occurrence of major, minor, and trace elements in ashes and flue gas.