Study Of Tube Wall Temperature Calculation And Life Assessment On High-temperature Confection Heating Surface Of Utility Boiler

With the vigorous development of China’s power industry, traditional thermal power plant in order to achieve a stable, economical, clean and efficient operation, the design parameters have been constantly improved. With the improvement of boiler unit economy, there are a lot of problems. Power plant boiler pipe rupture accident is one of the most common situations in power plant. Tube-burst accident has had a huge impact on the safety and economy in power plant. The occurrences of such problems are inextricably linked with the boiler tube wall over-temperature. So it is of great significance to comprehensively, accurately and reliably monitor the tube wall temperature of heat exchangers in power plants and it is necessary to conduct a reliable life assessment.However, the wall temperature measuring point of power plant boiler furnace is difficult to install. Even if installed, the high temperature in the furnace usually makes its life not long. What’s more, for the most dangerous place, the wall temperature cannot be obtained directly. At the same time, the existence of oxide film makes the over-temperature phenomenon more serious. It is even more difficult to assess the residual life accurately.Aiming at this problem, a detailed description and analysis of thermal deviation theory on boiler heating surface were given first. Then, a large power plant600MW subcritical swirl-opposed firing boiler was selected as research objective. Combustion simulation calculation was carried out based on numerical simulation software FLUENT, and gas temperature distribution on the high temperature superheater in furnace exit was got. Based on this research objective, Delphi language was used to compile the corresponding program for the calculation model. In the process of programming, the high temperature superheater tube was divided into several smaller units. Then combined with the site real-time data of high temperature superheater tube, this paper piecemeally calculated the heat and temperature of each pipe, and obtained the wall temperature distribution. At the last, Larson-Miller Formula was used to calculate the residual life. Combined with the results of the calculation, and assuming the oxide film exists, calculation and analysis of the effect was conducted again. This paper has significant engineering practical value, it can provide the correct guidance on the safety operation of power plant boiler, and also can put forward the guidance for power plant boiler pipe reparations.