Furnace Temperature Monitoring Technology And Temperature Field Construction Below Platen Superheater Bottom For Power Station Boiler

At present, with the increasing capacity of power plant boiler, the problem of slagging and overtemperature at platen superheater bottom is more prominent. Slagging at platen superheater would cause the high smoke temperature in the furnace exit of boiler, reduce the boiler thermal efficiency and even cause high temperature corrosion and tube burst. So, online measuring and temperature field reconstruction in the furnace gas temperature from boiler has a very important role in boiler’s security and economic operation. However, there is not a very accurate and high reliability device of online measuring in furnace gas temperature because of high fuel temperature and cold wall.Based on the numerical simulation on a 300 MW subcritical tangential firing boiler, this paper found the influence law of gas temperature distribution at platen superheater bottom by operation parameters such as primary air velocity, excess air ratio, over fired air ratio. Then we developed a kind of furnace gas temperature on-line monitoring equipment based on visible light after analyzing the special environment in the furnace. This equipment has a 10 mm probe, so it can be installed in the furnace water wall gap which could reduce the installation difficulty. What’s more, it is one kind of non-contact thermometry which could reduce the effects on the combustion. This paper described the composition of the equipment, the development process and the test on a 300 MW subcritical tangential firing boiler. At last, got the linear relationship between the standard temperature and the milliampere: t=47.3A+552, which was the basis of the design of display circuit.At last, with the aid of numerical calculation software, we did the discretization on the plane under the platen superheater, built a system of linear equations based on the measurement data, and solved it using regularization algorithm, reconstructed a two-dimensional temperature field with interpolation function. In the error evaluation standard, the normalized mean squared distance criterion was 0.661%, the normalized average distance criterion was 1.043%, which proved the reliability and accuracy of the algorithm.