DIGITAL MODEL OF WEAR OF HEAT EXCHANGE CONVECTIVE SURFACES OF A CHARCOAL BOILER

Abstract

The relevance of the study is caused by the need to use off-design coals on the operating equipment of TPPs. As you know, the use of such coals can adversely affect the operation, first of all, of a coal-fired boiler. The main aim of the research was to determine the overhaul period as well as the rate of low-temperature corrosion and the rate of abrasive wear of convective surfaces (air heater and water economizer) caused by the use of various coals (Azeisky, Mugunsky, Pereyaslоvsky and Irbeysky deposits) and their mixtures. Methods: mathematical modeling and complex optimization studies on models using System of Computer-Aided Construction of Programs, designed to generate mathematical models of the investigated installations based on mathematical models of individual elements, information on technological relations between them, and calculation purposes. This complex was developed at the Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences. Results. To assess the consequences of the use of non-design fuel, a sufficiently accurate mathematical model of the BKZ-420-140 steam boiler has been developed. Research was carried out on a mathematical model of the boiler in order to determine the optimal fuel compositions to minimize the operating costs associated with changing the fuel, and to increase the overhaul period of convective heating surfaces to improve the reliability of the boiler unit. The approximate dependences of the rate of low-temperature corrosion of metal on the average temperature of the pipe wall and the sulfur content of the combusted fuel are constructed. The technical and economic indicators of the boiler unit operation were obtained on the coals of the Azeisky, Mugunsky, Pereyaslavsky and Irbeysky deposits, as well as on coal mixtures (Azeysky coal (7 %) + Irbeysky coal (93 %), Azeysky coal (23 %) + Pereyaslovsky coal (77 % ), Pereyaslovsky coal (80 %) + Mugunsky coal (20 %), Irbeysky coal (95 %) + Mugunsky coal (5 %)).

Keywords

• coal-fired boiler
• abrasive wear
• low-temperature corrosion
• off-design coal
• mathematical modeling
• overhaul period