JPH0445211A - Method for controlling temperature of furnace wall in throat part of blast furnace - Google Patents

Abstract

PURPOSE:To enable the optimum control of dissipating heat quantity by estimating furnace gas temp. based on the measured value of furnace wall temp. and controlling pressure at the time of vaporizing cooling water vaporized in cooling metal or stave. CONSTITUTION:The temp. of furnace wall setting the cooling metal 3 is measured with a thermometer 12, and the pressure in an evaporator 7 is measured with a pressure gage 13. The measured temp. and pressure of furnace wall are outputted to the computing element 14, and based on the predetermined relation, the furnace gas temp. is estimated. Based on the estimated temp. and pressure of furnace gas, an opening/closing adjust signal is outputted to a pressure adjust valve 15 to optimize the furnace gas temp. By this method, even in the case the furnace gas quantity is decreased at the time of reducing production, as the furnace condition can be controlled to the optimum temp. without excess-cooling, the occurrence of detective furnace condition, such as the occurrence of slip, can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for optimally controlling the furnace wall temperature at the mouth of a blast furnace.

(Prior art) Conventionally, the furnace wall structure of a blast furnace has an uncooled ore support at the furnace mouth, uncooled bricks from just below it to the middle level of the shaft, and water-cooled bricks below that. Bricks are piled up, cooled by plates and staves.

However, due to the recent extension of the lifespan of blast furnaces, the bricks under the ore supports have fallen off, causing deterioration in furnace conditions. Therefore,
As a countermeasure, a water-cooled cooling hardware or a stave is installed on the inner side of the brick part of the furnace under the ore receiver to prevent the bricks from falling off.

(Problem to be solved by the invention) However, since forced cooling using a pump or evaporative cooling of natural circulation is used to cool the cooling hardware and staves, the temperature of the cooling water is at most 100°C. , the heat removal capacity is extremely large compared to the conventional case made only of bricks.

Therefore, when the amount of gas in the furnace decreases, especially during production cuts, the amount of heat removed from the furnace wall increases and the low-temperature region expands, resulting in an increase in reduction and pulverization of the sintered ore near the furnace wall. However, there was a problem of deterioration of furnace conditions such as occurrence of slippage.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for controlling the furnace wall temperature at the furnace mouth part, which can optimally control the amount of heat removed depending on the amount of gas in the furnace.

(Means for Solving the Problems) In order to achieve the above object, the furnace wall temperature control method at the mouth of a blast furnace according to the present invention provides a method for controlling the furnace wall temperature at the mouth of a blast furnace within a range of 6 m downward from directly below the ore receiving object at the mouth of the furnace. A method for controlling the furnace wall temperature of a blast furnace in which a water-cooled cooling hardware or a stave is disposed on the inner surface of the furnace wall, the method comprising: measuring the furnace wall temperature; The temperature is estimated and the pressure of the cooling water evaporated inside the cooling hardware or stave is controlled.

In other words, the amount of heat removed by the evaporation of the cooling water in the cooling hardware or the stave, Q, is as follows: Q = α・ (T, -T2) However, α: Overall heat transfer coefficient T1: Gas temperature in the blast furnace T2: Cooling water temperature I can do it.

Therefore, in the present invention, by measuring the temperature of the furnace wall where cooling hardware or staves are installed, the furnace gas temperature is estimated from the temperature, and the pressure during evaporation is adjusted so that the furnace gas temperature is optimized. By controlling this, the cooling water temperature T2 in the cooling hardware or stave changes, and the difference between it and the furnace gas temperature T changes, so the amount of heat removed can be controlled.

(Example) Hereinafter, the method of the present invention will be explained based on an example shown in the accompanying drawings.

In the drawing, 1 is an ore support installed at the mouth of the blast furnace 2, 3 is a cooling hardware installed on the inner side of the furnace up to the middle level of the shaft within a range of 6 m downward from just below it, and 4 is an ore support installed at the mouth of the blast furnace 2. The bricks are piled up below, and are cooled by the stave 5.

6 is a pipe for supplying cooling water to the cooling hardware 3, and 7 is an evaporator for the cooling water passing through the pipe 6.

That is, the cooling hardware 3 employs an evaporative cooling method. In addition, 8 is a pump for replenishing cooling water into the evaporator 7, 9 is a blast furnace shell, 1° is a castable, and 11
indicates the stock level.

The present invention is a method for controlling the temperature of the furnace wall at the furnace mouth of such a configuration, and is carried out as follows.

12 is a thermometer for measuring the temperature of the furnace wall where the cooling hardware 3 is installed; 13 is a pressure gauge for detecting the pressure inside the evaporator 7; the furnace wall temperature and pressure gauge 13 measured by this thermometer 12 are The pressure detected is output to the calculator 14, where:
The in-furnace gas temperature is estimated using a relational expression determined in advance based on the furnace wall temperature. Then, based on this estimated furnace gas temperature and pressure, an opening/closing adjustment signal is output to the pressure control valve 15 in order to optimize the furnace gas temperature.

Next, the results of experiments conducted to confirm the effects of the method of the present invention will be explained.

The table below shows the experimental conditions and results. When reducing production, the conventional method of reducing air flow without changing the evaporation pressure resulted in overcooling, which lowered the gas temperature in the furnace near the furnace wall and deteriorated the furnace condition. However, if the evaporation pressure is increased based on the measured furnace wall temperature as in the method of the present invention, and the evaporation temperature of the cooling water supplied to the cooling hardware is increased, overcooling is prevented and the furnace condition is restored. did.

Table (Effects of the Invention) As explained above, according to the method of the present invention, even when the amount of gas in the furnace decreases, such as when production is reduced, overcooling does not occur and the temperature can be controlled at the optimum temperature. It is possible to prevent the occurrence of deterioration of the furnace condition, such as occurrence of heat generation, as much as possible.

,

[Brief explanation of the drawing]

The drawings are schematic illustrations of the method of the present invention. 3 is cooling hardware, 7 is an evaporator, 12 is a thermometer, 3 is a pressure gauge, 14 is a computing unit, and 15 is a pressure control valve.

Claims (1)

[Claims] (1) 6m downward from just below the ore receiver at the furnace mouth
A method for controlling the furnace wall temperature of a blast furnace in which a water-cooled cooling hardware or a stave is disposed on the inner surface of the furnace wall within a range of 1. A furnace wall temperature control method at the mouth of a blast furnace, characterized by estimating the furnace gas temperature and controlling the pressure at the time of evaporation of cooling water that evaporates in cooling hardware or a stave.