Measurement Method And Application Of Slag-Iron Flow Rate At Taphole Of Blast Furnace Based On Optical Flow And Morphological Features

The slag-iron flow rate at taphole of blast furnace is not only the important parameter for characterizing the pressure and air permeability in blast furnace,but also data basis for realizing taphole tapping status identification,slag-iron ratio detection and taphole plugging time determination.Due to the characteristics of high temperature,strong corrosiveness,fast flow rate and non-transparency of slag-iron at taphole of blast furnace,and the interference of strong dust in taphole environment,the existing fluid flow rate measurement methods are difficult to be directly applied,resulting that it is difficult for detecting flow rate of slag-iron at taphole of blast furnace.Therefore,according to the characteristics of slagiron and the environment at taphole of blast furnace,the on-line flow rate measurement method of slag-iron at taphole of blast furnace based on optical flow and morphological features is studied,and the on-line flow rate measurement system of slag-iron at taphole of blast furnace is developed,which realizes the on-line stable flow rate measurement of slagiron at taphole of blast furnace under the environment of dynamically changing dust.The main research results and innovations of this thesis are as follows:(1)The change of illumination and moving boundary on the surface of slag-iron jet will reduce the detection accuracy of optical flow.Therefore,a method for detecting the surface flow field of slag-iron jet based on mutual-guided optical flow model is proposed.An intensity aggregation metric which can distinguish structure information from texture information is constructed,and the extraction method of surface texture information of slag-iron jet based on intensity aggregation metric is studied.The structure information containing illumination change is removed,and the influence of illumination change on optical flow detection accuracy of slag-iron jet surface is weakened from the source;The optical flow mutualguided filter used to protect the moving boundary is studied,and the mutual-guided optical flow model based on the optical flow mutual-guided filter is established.The detection method of slag-iron jet surface flow field based on alternating iterative strategy is studied.By protecting the mutual structure region in the flow field,the blurring problem of moving boundary flow field is improved,and the accurate detection of slag-iron jet surface flow field is realized.(2)To address the problem that it is difficult to get the average crosssectional velocity of slag-iron at taphole by inversion of the surface flow field of slag-iron jet,a velocity measurement method of slag-iron at taphole of blast furnace based on jet trajectory model is proposed.Based on ANSYS-Fluent,the simulation model of slag-iron outflow in blast furnace taphole is established,the movement trend of surface flow field and internal flow field of slag-iron jet is obtained,and the important conclusion that the surface velocity in the back section of slag-iron jet is equal to the cross-sectional average velocity is obtained;Based on the assumption of uniform cross-sectional flow field,a jet trajectory model is constructed.A fluid jet experimental platform is built to verify the effectiveness of the jet trajectory model.A velocity measurement strategy of slag-iron at taphole based on the jet trajectory model is proposed,and the average crosssectional velocity of iron jet of taphole slag is obtained,which realizes the accurate velocity measurement of slag-iron at taphole.(3)Aiming at the problem that the measurement accuracy of slag-iron velocity at taphole and taphole radius decreases under the environment of dynamically changing dust,an on-line stable flow rate measurement slagiron at taphole based on boundary mixed morphological features is proposed.The edge detection algorithm of slag-iron jet based on efficient edge-preserving filtering is designed,and the parabola detection method based on distance voting Hough transform is studied,which realizes the synchronous detection of slag-iron jet boundary and taphole radius based on boundary continuity,and overcomes the problem that the measurement accuracy of taphole radius decreases under the environment of dynamically changing dust;The boundary mixed morphological features used to quantify the boundary morphological information of slag-iron jet are extracted,and the flow rate measurement model of slag-iron at taphole is constructed based on RBF neural network and support vector regression model;A parameter determination method of RBF neural network based on semi-fuzzy clustering algorithm is proposed,and the on-line stable flow rate measurement of slag-iron at taphole is realized under the dynamic dust change environment.(4)Combined with the research results of this thesis,the hardware platform of on-line detection system is designed,and the on-line flow rate measurement system of slag-iron at taphole of blast furnace taphole is developed,which is applied to the tapping process of blast furnace in an iron and steel plant,and realizes the functions of video monitoring of slagiron jet,flow rate measurement of slag-iron at taphole and threedimensional display of slag-iron jet,etc.It provides accurate slag-iron flow rate at taphole for the first time,greatly shorten the treatment time of abnormal tapping state at the tapping site,and provides a large amount of data support for ensuring efficient and stable tapping of blast furnace.