Effect of NaOH treatment on combustion performance of Xilinhaote lignite

The combustion characteristics of NaOH treated and untreated Xilihaote lignite was investigated by thermogravimetric analysis. The relationship between physico-chemical properties, including the ash content, oxygen-containing functional groups, mean pore diameter and specific surface area and combustion performance, was also studied in this paper. Combustion kinetic parameters were calculated through Coasts Redfern Method. The results show that ignition of treated samples takes place at higher temperature compared to raw lignite, and peak temperature also occurs at higher temperature. The maximum combustion rate of the sample, which was treated by 0.01 mol/L NaOH lignite, was the biggest. Reaction orders of 0.6, 2.0, and 0.8 were found to be effective mechanism for definite three temperature regions. Average activation energies of these three temperature regions of XLHTR, XLHT0.01, XLHT0.50 and XLTH1.00 are 19.17, 23.87, 10.77, and 10.93 kJ/mol, respectively. Treatment of lignite with NaOH can reduce the reactivity of lignite at proper concentration.