Reconstruction of the tail heating surfaces of CHP boilers in order to improve the efficiency

• Published in: IOP conference series. Earth and environmental science Vol. 751; no. 1; p. 12011
• Main Authors: Kudryashov, A N, Koval, T V
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.04.2021
• Subjects: Air heaters; Air temperature; Boilers; Coal; Cogeneration; Corrosion; Corrosive wear; Electric power generation; Flow rates; Flow velocity; Flue gas; Fuels; Heat; Heating; High flow; Lignite; Low temperature; Power plants; Sulfur; Sulfur content; Sulfuric acid; Thermal power; Thermal power plants; Vapors; Wear
• ISSN: 1755-1307; 1755-1315
• DOI: 10.1088/1755-1315/751/1/012011

Recently, the share of non-design fuel use of coal at thermal power plants has increased, which negatively affects the operation of existing equipment. On the territory of the Irkutsk Region, there are 9 combined heat and power plants operating mainly on brown coals of the Irkutsk and Kansk-Achinsk basins. The main fuel at many CHPs is brown coal from the Mugunskoye deposit, the quality of which is deteriorating year by year. At the Novo-Irkutsk CHP, there is a prospect of continuing the supply of the Mugunsky coal with a sulfur content of up to 2.5%, which significantly exceeds the sulfur content of the design coals, which is 0.5%. This leads to the condensation of sulfuric acid vapors in the flue gases and, as a result, the heating surfaces are subject to sulfuric acid corrosion. In addition, there is a problem of erosive wear of air heaters at CHPs, caused by high flow rates and ash concentrations, which is also caused by a deterioration in the composition of the burnt coal. To solve the problem associated with low-temperature sulfuric acid corrosion of the boiler air heater tanks, it is proposed to place additional heating surfaces in the bypass gas ducts, which will reduce the temperature of the gases by cooling the flue gases with network water, and allow the obtained heat to be used in the added sections of the calorifier for heating the inlet (cold) air. While bypassing 25% of gases using the heat of gases in the calorifiers, erosion wear is reduced due to a decrease in the gas velocity in the air heater from 13 m/s to 9 m/s. The proposed technical measures will make it possible not only to increase the efficiency of the boiler and the plant as a whole, but also to increase the degree of fuel heat use.