Study Of Temperature Measuement System For Boiler Superheater Wall Based On The Infrared Imaging Technology

In the coal-fired power plant boiler operation,temperature is one of the most significant parameters.The high-temperature superheater suffers from a very harsh environment and high temperature,the accurate measurement of the wall temperature has always been a key and difficult point in the boiler technology.The investigation of the wall temperature measurement can contribute to understanding the physical and chemical reactions in the superheater running process,and figuring out the operation law and tube's remaining life,which can not only optimize the boiler running,but also help boiler engineers to improve their products.In this paper,a non-contact temperature measurement method based on the infrared imaging technology is proposed to measure the high-temperature superheater wall temperature distribution.Firstly,some related concepts on infrared radiation transmission mechanism are presented,and on this basis,the basic principle is introduced about the radiation temperature measurement.Then the working principle and structure of infrared CCD camera is presented and the Generalized Source Finite Volume Method is used to solve the arbitrary directional radiative intensity in multi-dimensional semi-transparent media.On the basis of the above conditions,a temperature measurement mathematical model based on infrared images is presented to measure the temperature of the high temperature superheater wall covered by coal-fired flue gas.In this model,the LSQR and QPSO algorithms are used to solve the flue gas physical parameters and the real temperature distribution of the superheater wall.In order to study the effect of the flue gas physical parameters on the radiative transfer and the temperature calculation,the reliability of these algorithms including the GSFVM,LSQR algorithm and QPSO algorithm are validated.Based on the numerical validation,the influence of the flue gas physical parameters on the wall temperature measurement is analyzed,and the results show that the infrared image method is effective to measure temperature.Experimentally,a blackbody furnace is used to set up the CCD camera calibration experiments in order to establish the relationship between the blackbody temperature and the radiative intensity.Then the main temperature measurement experimental platform is built,which includes the wall environmental simulation system,the related data acquisition system and the infrared imaging system.In the experiment,the flue gas generating device is used to generate different concentration and thickness flue gas,and after the main experiment the effect of flue gas concentration and thickness on the temperature measurement is analyzed,and the flue gas properties and the real temperature data are confirmed.Based on the infrared image temperature measurement method,a set of wall temperature measurement system was designed for the field test on the 4#1000MW unit of Jinghai Power Plant in Guangdong province to measure the temperature on the second tube screen wall of high temperature superheater.This system mainly includes the imaging device cooling system and the data collection system.Fully considering the influence of the environmental factors inside and outside the furnace,the cooling system ensures the running temperature of the imaging equipment to keep normal.The data processing system ensures to meet the requirements of the main control room.Finally,the field test data were extracted and analyzed,and the reliability of the infrared image temperature measurement method has been proved.