Monitoring and control of hearth refractory wear to improve blast furnace operation

Abstract

Refractory wear and skull growth on the hearth walls and the bottom of the blast furnace have been researched. A series of thermocouples were installed in the hearth, and the temperature measurements were recorded in a structured query language every minute. A heat transfer model was used to study the temperature evolution and hearth wear profile using a commercial software package (MATLAB version 5.0) based on computational fluid dynamics. The location of the 1150uC isotherm in the hearth lining has been calculated. An online monitoring tool was used to analyse the temperature distribution in the hearth and offers, to the plant operators, periodic information on the refractory state. Electromotive force (EMF) probes were installed in the hearth to estimate the variations in the liquid level in the hearth and to determine the thermal state (TS) evolution. Good correlation is seen between EMF and TS, and the EMF amplitudes in the different tapholes follow and even precede the local TS.

Blast Furnace Hearth Lining: Post Mortem Analysis

“…The non-milled samples were conducted to Scanning Electronic Microscopy (SEM) with X-ray Spectrometry (EDS) 6,7,8,9,10,11 .…”

“…The determination of wear mechanism is fundamental to better understand what happens into the refractory lining during the hot metal production, and it is the basis to decide the better option to protect this refractory layer to improve the furnace campaign. In this way it is possible reduce both the total cost of production and the refractory consumption of this important industrial activity 5,6,7 .…”

“…However, the corrosion mechanism is a result of the chemical nature of the raw materials used to produce hot metal wherein the alkali compound were the main degradation agents 7,8 . In 2000 the #2BF showed the typical wear profile configuration reported by the lecture along the refractory thickness, from the hot face to the cold face: Lost layer; Protective layer; Hot metal penetrated layer; Brittle zone; Slightly changed layer and Unchanged layer 8 .…”

“…Both the liquid penetration and the hot gaseous infiltration are allowed through the open porosity this refractory material 5,6,7 . The #2 blast furnace hearth lining of Companhia Siderurgica Nacional (CSN) are composed graphite refractory blocks.…”

Support algorithm for blast furnace operation with optimal fuel consumption

“…Therefore, for many years research centers have tried to facilitate control of the BF process by modelling particular phenomena and analyzing the entire process. Apart from the usual monitoring of real BF processes [1,2] and mathematical and numerical models [3][4][5][6][7], which can be supported by physical cold models [8][9][10][11], the common use of neural networks for controlling hot metal quality and temperature [12][13][14][15][16][17] should be mentioned. Advanced methods such as genetic algorithms [18,19], subspace methods [20][21][22], or fuzzy clustering [23] are also reported.…”