Research On The Methods Of Compensation For Improving The Measurement Accuracy Of Rotary Kiln

Rotary kiln is a large-scale calcining equipment in cement,steel,glass and environmental protection industries.As one of the important thermal parameters of rotary kiln,temperature must be monitored comprehensively in the production process.At present,infrared scanning method is usually used to measure the surface temperature of rotary kiln comprehensively.However,because of the large size and complex environment of rotary kiln,the accuracy of temperature measurement is limited by many factors such as environmental temperature,temperature measurement distance and so on.Aiming at the main influencing factors in the process of temperature measurement in rotary kiln,an effective compensation method for temperature measurement is proposed to further improve the accuracy of temperature measurement.This project is supported by the project of National Natural Science Foundation of China "High Precision Rotary Kiln Carcass Infrared Dual-band Scanning Temperature Measurement Method and Experimental Research(61671094)" and the cooperation project of school and enterprise "Surface Temperature Monitoring System of Rotary Kiln Based on Infrared Radiation".At present,there are many studies on the influence factors of infrared temperature measurement,but most of them are theoretical studies with low practicability.In addition,there is a big gap in the research on infrared temperature compensation model under the application scenario of rotary kiln.Through investigating and analyzing the working environment of rotary kiln,it is found that there are two main factors affecting the temperature measurement accuracy of rotary kiln: environmental factors(ambient temperature)and measurement factors(Scanning angle,distance).In view of the influence of environmental factors,this paper obtains the attenuation law of ambient temperature with distance by analyzing the uneven distribution of ambient temperature around rotary kiln,and then based on the composition of detector receiving radiation,the calculation formula of system temperature is revised,and the dynamic temperature compensation model based on non-uniform temperature field is established.Aiming at the influence of measurement factors,the influence of measuring distance on temperature measurement is found by simulation experiment with standard black body.Combining with the deviation of angle and distance caused by horizontal and vertical direction of rotary kiln,a temperature compensation model based on multi-direction fusion is established.Finally,the compensation model of two factors is fused to construct a multifactor surface temperature compensation model to improve the accuracy of temperature measurement and ensure the real-time,accurate and efficient operation of rotary kiln.In this paper,the validity of this model is verified by laboratory and factory field verification.The experimental results show that when the temperature compensation of environmental factors is only considered,the average relative error of measurement increases by about 5%.When the temperature compensation of measurement factors is only considered,the average relative error of measurement increases by about 6%.Compared with that of single model,the measurement accuracy of the fused model increases by about 3%.The compensation model of infrared temperature measurement established in this paper effectively improves the accuracy of temperature measurement on the surface of rotary kiln,and has important reference value for the research of high precision infrared scanning temperature measurement method.