高温受热面壁温智能调节系统开发及应用

Development and application of an intelligent control system forwall temperature of high-temperature heating surfaces

大容量、高参数的对冲燃烧煤粉锅炉常因高温受热面壁温分布不均影响运行安全性和经济性。针对该问题,通常需开展制粉系统或燃尽风的优化调整,但由于壁温分布可能随锅炉运行工况变化,单次优化调整结论无法适应所有工况。基于壁温调节原理设计了燃尽风智能调节策略,优化了燃尽风装置的进风结构并配备电动执行器,开发了一套高温受热面壁温智能调节系统,旨在实现燃尽风优化调整的自动化和智能化。在某1000 MW机组开展了高温受热面壁温智能调节系统的实炉测试,对比了不同负荷下未投用和投用该系统后高温过热器出口的壁温分布及高温过热器、屏式过热器出口汽温与最高壁温的偏差随时间的变化趋势,统计了不同负荷段未投用和投用该系统后高温过热器、屏式过热器出口汽温与最高壁温的平均偏差。结果表明,不同负荷下,高温受热面壁温智能调节系统均可根据受热面实时壁温分布,自动调整各燃尽风的开度和摆角,使受热面沿炉宽方向壁温分布趋于平均。不同负荷下,高温受热面壁温智能调节系统均可显著降低壁温偏差,屏过出口壁温偏差由50℃降至20~30℃,高过出口壁温偏差由20℃降至12℃。投用高温受热面壁温智能调节系统可显著降低因负荷变化而增大的壁温偏差。高温受热面壁温智能调节系统可在调平壁温的同时调平氧量。

Large capacity and high parameter opposite firing boilers are often affected by uneven wall temperature distribution on high-temperature heating surfaces,which affects their operational safety and economy.To solve this problem,it is usually necessary to carry out optimization of the pulverization system or over-fire air.However,due to the variation of wall temperature distribution with boiler operating 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 1000 MW unit for the intelligent control system.The wall temperature distribution at the outlet of the high-temperature superheater and the variation trend of the deviation 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 temperature 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 deviation at the outlet of the high-temperature superheater is reduced from 20℃to 12℃.The system can significantly reduce the wall temperature deviation that increases due to load changes.The system can leveling O_(2)concentration while leveling wall temperature.