Study On Application Of Rotary Kiln Temperature Soft Measurement Technology

Pellets is an important material for blast furnace.With the development of domestic and international steel industry,the quality improvement of pellets has a vital role in economic indicators of the production technology and also impact on dominant business position in the competition.The temperature measurement and control is an important part in the rotary kiln's roasting process.It has a key role in the quality of the calcined material and significance to the process conditions of production,the safety of production,the reducing of energy consumption and so on.The thermal process of rotary kiln is complex,and the process is a nonlinear multi-variable system which has large time delay result in obtain real-time and accurate temperature information is very difficult.In view of the above problems,the research work and innovation are as follows:(1)First of all,based on the analysis of rotary kiln's thermal system,a temperature mathematical model which is according to the rotary kiln inside and outside the heat conduction,heat radiation mechanism has been proposed.Through the surface of the rotary kiln temperature,ambient temperature,refractory section temperature of auxiliary variables the model can calculate the temperature inside the kiln.Calculation to verify the model with production data that has good accuracy in a certain period of time,but when the production of the parameters was changed,the mechanism model can not accurately predict the actual temperature in the kiln.(2)Then,aiming at the defects of mechanism model,this paper proposed a temperature soft measurement which based on extreme learning machine(ELM)algorithms to identify the parameters of mechanism model.The model using the nonlinear approximation capability of ELM network,achieve undetectable parameter in the mechanism model through the training data to identify the parameters of the mechanism model.The soft measurement model of temperature parameters identification which has better precision has been verified through the simulation experiment.Due to the slow change in the production,the soft sensor model shouldn't be used to correct the accuracy of online learning and therefore save a lot of time,which lays the foundation for the temperature control in the kiln.(3)Finally,hardware and software system of rotary kiln's temperature soft measurement have been designed in this paper.The hardware system collection data which is the soft measurement model required and the PC complete calculation by software to realize soft measurement and monitoring of the temperature in rotary kiln during pellet production process.Experimental results have showed that it is a good temperature soft measurement system for rotary kiln.