Development and application of an intelligent control system for wall temperature of high-temperature heating surfaces
Large capacity and high parameter opposite firing boilers are often affected by uneven wall temperature distribution on high-tem-perature heating surfaces,which affects their operational safety and economy.To solve this problem,it is usually necessary to carry out opti-mization of the pulverization system or over-fire air.However,due to the variation of wall temperature distribution with boiler operat-ing conditions,the conclusion of a certain optimization cannot adapt to all operating conditions.Based on the principle of wall temperature regulation,an intelligent control strategy for over-fire air was designed,and the inlet structure of the over-fire air device was optimized and equipped with an electric actuator.A high-temperature heating surface wall temperature intelligent control system was developed,aiming to achieve automation and intelligence of over-fire optimization.Experimental research was conducted on a 1 000 MW unit for the intelli-gent control system.The wall temperature distribution at the outlet of the high-temperature superheater and the variation trend of the devia-tion between the outlet steam temperature and the highest wall temperature of the high-temperature superheater and screen superheater were compared under different loads before and after the system was put into use.The average deviation between the outlet steam tempera-ture and the highest wall temperature of the high-temperature superheater and screen superheater in different load stages was statistically analyzed.The results show that under different loads,the system can automatically adjust the opening and swing angle of each over-fire air based on the real-time wall temperature distribution of the heating surface,so that the wall temperature distribution of the heating surface along the furnace width direction tends to be average.Under different loads,the system can significantly reduce wall temperature deviation.The wall temperature deviation at the outlet of the screen superheater is reduced from 50 ℃ to 20-30 ℃,and the wall temperature devia-tion at the outlet of the high-temperature superheater is reduced from 20℃to 12 ℃.The system can significantly reduce the wall temper-ature deviation that increases due to load changes.The system can leveling O2 concentration while leveling wall temperature.
万方数据
维普
