1 025 t/h锅炉再热器超温处理及可行性分析

针对某1 025 t/h锅炉再热器管壁超温、减温水量大的问题，通过现场试验、数值模拟和热力计算等方法，分析管壁超温和减温水量大的原因，提出燃烧调整和受热面改造方案。研究表明：该锅炉末级再热器出口管壁温度存在较大偏差，烟道中间及右侧部分管壁超温，原因在于炉膛出口的烟温偏差；通过将燃尽风由四角均匀配风调整为左侧风门开度50%、右侧风门开度100%,降低了炉膛出口左右两侧的烟温偏差，进而减小了再热器出口的壁温偏差；针对锅炉再热器、过热器减温水量大的问题，进行二次风优化调整，当二次风正塔配风时炉膛出口温度比二次风均等配风和束腰配风时有所降低，有利于降低减温水量；该炉二次风配风优化难以从根本上解决减温水量大的问题，为此提出减少再热器、过热器受热面及增加省煤器受热面的改造方案，使减温水量在不同负荷下均能满足锅炉运行要求。

Modification and Feasibility Analysis of Reheater Overheating of 1 025 t/h Boiler

To reduce the overheat of reheater tube wall and the large amount of desuperheating water of a 1 025 t/h boiler, the cause was analyzed by field tests, numerical simulation and thermal calculation, and the combustion adjustment and heating surface modification schemes were proposed.The research results show that there is a large deviation in the outlet temperature of the final stage reheater, and the overheat exists in the middle and right partial tube walls of the flue, due to the deviation of the flue gas temperature at the furnace outlet.The deviation of the flue gas temperatures on the two sides of the furnace outlet is reduced, and then the deviation of the reheater outlet temperature is also decreased by changing the uniform air distributionat the four corners of burn out air into the left damper opening of 50% and right damper opening of 100%.Aiming at the large amount of desuperheating water of boiler reheater and superheater,the optimization adustment of secondary air is performed.When the tower type distribution is used for secondary air, the temperature at the outlet of the furnace is lower than that of the secondary air with equal distribution and the waist type distribution, which is conducive to reducing the amount of desuperheating water.The optimization of secondary air distribution in this furnace cannot fundamentally solve the problem of large amount of desuperheating water.Therefore, the modification scheme is proposed to reduce the heating surface of reheater and superheater and increase the heating surface of economizer, which can meet the requirements of boiler operation under different loads.