Increasing Thermal Power Plant Efficiency by Improved Lignite Combustion

The coal market and its prospects are analyzed, with a focus on the use of lignite at thermal power stations. Switching to lignite—on account of economic factors and the exhaustion of other coal supplies—lowers the efficiency of power station equipment and increases operating costs. Slagging, corrosion, and buildup at the heating surfaces in lignite combustion cause problems. The effects of nonuniform radiant flux distribution in the boiler are considered. Methods of reducing the emissions of sulfur and nitrogen oxides are studied: for example, the injection of drying gases; swirling combustion; and stepwise fuel supply. Proposals are made for upgrading the boiler systems, including reconstruction of the burners and convective heating surfaces. Technologies for fuel preparation and cleaning the heating surfaces are noted. Particular attention is paid to slagging and its dependence on the coal composition. The conclusion is that an integrated approach to lignite combustion is needed, including modernization of the equipment, the development of new technologies, and optimization of the operating conditions so as to ensure safe and effective lignite combustion.