Thermal Analysis of the Combustion of Lignite–Biomass Mixtures

摘要

Abstract The combustion of lignite, biomass (pine cones), and their mixtures (in different proportions) is investigated by simultaneous thermal analysis. In the analysis, ~6-mg samples are heated in an oxidative atmosphere at 20°C/min, with an air flow rate of 50 mL/min. The thermal characteristics and elemental composition of the solid fuels are determined by standard methods. Analysis of the heating of the fuel mixtures and their components indicates that combustion occurs in different temperature ranges: 258–549°C for lignite; 220–503°C for pine cones; and 230–536°C for their mixtures (depending on the proportions of the components). The coke residue of the pine cones ignites at 302°C, which is 58°C lower than the value for lignite (360°C). Adding 25–75 biomass to lignite lowers the ignition temperature of the mixture by 21–56°C. Predicting the basic combustion characteristics of the mixture by appropriate summation of the components’ characteristics is possible if the biomass content is no more than 25. With higher biomass content, the influence of the components on the combustion characteristics of the mixture is nonproportional, over a broad temperature range