Experimental and analytical evaluation of the drying kinetics of Belchatow lignite in relation to the size of particles

Water removal is a key technology for enhancing efficient utilization of lignite in power generation. An inherent characteristic of lignite, attributed to the large amount of water kept within the fuel, is the factor decreasing the thermal efficiency of lignite-fired power plants. This paper presents the research results on investigating the drying kinetics of Belchatow lignite excavated in the Central Poland in prior to developing a water removal system. Lignite drying test was conducted in superheated steam atmosphere at the temperature range of 110-170 °C. Spherically shaped samples, of which the diameter is 2.5 mm, was used. The experimental results were then analysed with previously conducted measurements of 5, 10, 30 mm samples to investigate the influence of particle size. The presented analysis shows the agreement of the evaluated drying rate at the CDRP to the experimental data. The obtained experimental results were used to predict the drying behaviour of the group of particles. The proposed investigation clarifies the size dependence of the drying characteristics of the multisize group of lignite particles.