Research On Key Thermal State Characteristics Of Electric Fused Magnesium Furnace

Fused magnesia is a kind of important refractory material with high temperature resistance,corrosion resistance and good insulation.It is used in metallurgy,aerospace,electronics and other industries.Adopt China’s unique three-phase AC electric magnesium melting furnace for smelting,the fused magnesium furnace is a three-phase AC submerged arc ore furnace,which uses the electric arc as the main heat source and is accompanied by the molten pool resistance.During the production process,the thermal status of the furnace is very complicated.The strong non-linearity and random changes of the heat source arc make the working state of the fused magnesium furnace extremely unstable,which has a deleterious effect on the power quality of the local power grid,energy consumption per ton of product,and product grade.Therefore,deepening the understanding of the characteristics of the thermal state of the furnace,especially the characteristics of the molten pool penetration state and the relative heating ratio of the arc,is helpful to optimize the smelting production process and improve the production efficiency of the fused magnesium furnace.However,due to the harsh smelting production environment,high temperature and high dust;the arc,which is closely related to the working conditions in the furnace,is a conductive,highspeed,high-temperature continuously changing plasma,making it difficult to directly monitor the thermal status of the furnace.Based on the industrial experimental platform of a refractory factory in Yingkou,Liaoning,this paper aims to gain a deep understanding of the characteristics of the molten pool penetration state and the specific heat generation state of the arc in the electric melting magnesium furnace.Two analysis strategies based on electrical energy index data and power supply system,arc model.Developed a key thermal status analysis system for fused magnesium furnaces and verified it by industrial experiments.The main work of this article is as follows:(1)Aiming at the problem of characteristic analysis of molten pool penetration status,an algorithm based on electrical energy index data to identify penetration status was proposed.The algorithm specifically includes two methods:FFT fast Fourier transform and power quality index.Based on the change of the electric energy index and the current and voltage amplitude,firstly,the identification criterion of the material discharge period is given,and the melting state of the molten pool in the unmelted,semi-melted,and molten phase is further divided.Identifying the molten pool penetration state can control the size of the input current and the timing of the ore injection,reduce the proportion of the time of the bad operation state under the beating cycle,and optimize the smelting production process.(2)Aiming at the problem of characteristic analysis of arc relative heating ratio,an algorithm for analyzing arc relative heating ratio based on power supply system model and arc model was proposed.The algorithm uses genetic algorithms to identify unknown parameters of the arc model,and then,when the power supply system model and the arc model parameters are known,the relative heating ratio of the arc can be calculated for any discharge period.By calculating the relative heating ratio of the arc,it is possible to gain a deeper understanding of the combustion state of the arc and improve the smelting production efficiency of the electric furnace.(3)In order to verify the algorithm,a key thermal state characteristic analysis system for fused magnesium furnace was designed and developed.The hardware platform of the system is composed of related peripheral equipment such as data acquisition boards,system transmission cases and current sensors.The software part consists of basic parameter storage configuration module,waveform monitoring module,data analysis module and so on.The software platform is based on NI MAX and Labview to form a data communication and human-computer interaction system,and calls the module that encapsulates the data analysis function in MATLAB,so that device configuration and application programming can be performed in the same programming environment of Lab view.(4)The key thermal state characteristic analysis system of the fused magnesium furnace developed in this paper was verified by industrial experiments in a refractory plant in Yingkou,Liaoning.Verified the system data real-time acquisition,storage and monitoring functions and system reliability and security.The detrimental effects of charging on power grid energy indicators are given,specific criteria for identifying the molten pool penetration status and the relative heating ratio of the arc during the charging cycle are analyzed.The above experimental results prove the effectiveness and rationality of the proposed method and the developed system.