Research On Residual Oxygen Detection System Based On Zirconia Sensor

The heating furnace is a complex thermal equipment in the metallurgical industry.How to improve the combustion efficiency of the heating furnace is an urgent problem to be solved in the metallurgical field.A reasonable air-fuel ratio is an important parameter to improve the combustion efficiency of the furnace.However,the air-fuel ratio cannot be directly measured at the site,and the air-fuel ratio is usually adjusted by detecting the residual oxygen content of the furnace.Therefore,accurate measurement of residual oxygen content plays an important role in improving the efficiency and quality of production operations.The zirconia oxygen analyzer can monitor the oxygen content in high dust,high temperature and mixed gas with its unique reaction mechanism,and is widely used for measuring the oxygen content of various heating furnaces.At present,the development of domestic oxygen analyzers is relatively lagging behind.The specific performances are: low measurement accuracy,unstable sensor operation and short instrument life.Therefore,zirconia gas oxygen with high precision,high performance and high reliability has been developed in China.The analyzer has research significance,and successful implementation can bring considerable economic benefits and significant social benefits.The overall study of this paper is divided into the following two parts:In the first part,the analysis of the oxygen measurement principle of the zirconia probe shows that the improvement of the oxygen measurement equation and the constant control of the probe operating temperature are the key techniques to improve the detection accuracy.Based on this paper,the instrumentation processing of the oxygen measurement equation and a segmented incremental PID control algorithm are proposed and applied to the residual oxygen content detection system,which effectively improves the measurement accuracy and stability of the system.This system uses Altium Designer software to design the hardware circuit and PCB board of the system.The ARM software program of the system is completed by MPLAB IDE.The anti-interference ability and detection accuracy of the residual oxygen concentration detection system are improved by means of STM32F405 RG as the core control device circuit design,signal conditioning and linearization processing.Through on-site application,the requirements for accuracy and stability of residual oxygen content detection are fully met.In the second part,based on the feedback from the field,it is found that the traditional zirconia oxygen sensor has a short life in harsh environments.Therefore,the idea of using soft-measurement technology to detect residual oxygen content withtraditional instruments is proposed.The soft measurement method used in this paper is to predict the residual oxygen content in the heating furnace after optimizing the LSSVM parameters by the whale algorithm.The auxiliary variables are selected through the analysis of the heating furnace process,and then the auxiliary variables are filtered by the gray correlation degree.Finally,the input of the model is trained to predict the residual oxygen concentration.It is proved by experiments that this idea has great research value and practical significance.