JPS63219513A - Cooling method for wall of blast furnace - Google Patents

Abstract

PURPOSE:To properly cool wall of a blast furnace and stabilize the operation of the furnace, by blowing a cooling medium into the furnace from through holes in the wall and controlling the amt. of the cooling medium blown according to the temp. of the internal part of the furnace close to the through holes. CONSTITUTION:Water or a water-gaseous N2 mixture as a cooling medium is blown into a blast furnace from blowing nozzles 13 through a cooling pipe 14, an on-off valve 15 and flow rate regulating valves 16 to cool the wall 10 of the furnace by the heat of evaporation of the water. At this time, the temp. of the wall 10 is measured with a thermometer 17-1 for the interior of the furnace, a thermometer 17-2 for the shell 11 and a thermometer 17-3 for a stave and the measured value is inputted in a control relay 18. This relay 18 decides the degree of opening of each of the valves 16 according to the inputted temp. and instructs the valves 16 on the degree of opening so that a proper amt. of the cooling medium is blown into the furnace. Thus, the wall of the furnace is properly cooled by the cooling medium at all times and furnace cooling due to deficient soaking is not caused.

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a method for effectively cooling the furnace wall of a blast furnace.
More specifically, the present invention relates to a method of cooling a furnace wall by blowing a cooling medium into the furnace by penetrating the furnace wall.

Technical Background The furnace wall of a blast furnace is composed of an iron shell, furnace wall cooling devices such as a stave cooler and cooling plate, and refractory bricks.
When a blast furnace has been in operation for a long time, damage to the refractory bricks, damage to the staple cooler and water cooling pipes of the cooling plate, etc. may occur.
The red heat of the steel shell causes damage to the furnace wall, such as cracking of the steel shell, making stable operation of the blast furnace difficult and, in some cases, creating the risk of a major accident. Furthermore, if the furnace wall becomes severely damaged, it becomes difficult to maintain production capacity, which causes the blast furnace to stop blowing.

Therefore, in blast furnace operation, measures to protect the furnace walls are extremely important, and various measures have been taken in the past.

Conventional technology and its problems Protective measures for blast furnace walls include repairing damaged parts by injecting mortar into the damaged parts of the furnace, spraying casters, etc., spraying water outside the shell, and blowing cooling gas into the furnace. There are cooling methods.

However, repair of the furnace wall by pouring mortar or the like cannot be carried out unless the blast furnace is shut down, so a decrease in the blast furnace operating rate is inevitable. In addition, injecting cooling gas into the blast furnace is an effective method in that it can cool the furnace wall during operation, but if the heat load on the furnace wall is large, it is necessary to inject a large amount of cooling gas into the blast furnace. It is necessary to blow into the inside of the body, and there is a problem with flowability. Therefore, in terms of cooling effect and economic efficiency, there is a need for a method of cooling the blast furnace wall that has a significantly larger cooling capacity and is also economically advantageous.

Means for Solving the Problems The present invention solves the above-mentioned conventional problems by providing a through hole in the wall of the blast furnace, through which water or a cooling medium mixed with water and cooling gas is blown. In addition, we have proposed a method for controlling the amount of injection according to the temperature inside the furnace or the temperature of the furnace wall.

That is, this invention cools the furnace wall with high cooling capacity by cooling using the heat of evaporation of water, and further measures the furnace internal temperature or furnace wall temperature in order to prevent excessive cooling and obtain an appropriate cooling effect. This is a method in which an appropriate amount of cooling medium is blown into the furnace depending on the measured temperature value.

This invention will be explained in detail below.

As is well known, water evaporates at about 100'C, and at this time, about 500 to 600 Kcal/1 water is absorbed as heat of evaporation from the atmospheric gas, etc., thereby lowering the temperature of the atmospheric gas.

This invention is a method for cooling the furnace wall by causing the heat of vaporization reaction to occur in the blast furnace and lowering the gas temperature in the furnace near the furnace wall. However, since water has a large cooling effect due to the heat of evaporation, if too much water is injected as a cooling medium, the gas inside the blast furnace and the blast furnace contents such as ore and coke will be excessively cooled. There is a risk that the lack of heat will cause furnace cooling, etc., or that more deposits than necessary will be formed on the furnace walls, which will impede blast furnace operation.

As a countermeasure against this problem, the present invention measures the temperature inside the furnace or the temperature of the furnace wall, and adjusts the amount of cooling water blown while checking the cooling effect based on the measured temperature value, thereby preventing furnace cooling due to excessive cooling and excessive loading. It is designed to prevent kimono formation.

Further, when water is blown in a mist form, a wider range can be cooled than when water is blown in a liquid form, and extreme local overcooling can be prevented, so a mist is preferable as a cooling medium. Water can be made into a mist by making the water outlet smaller and increasing the discharge speed, or by mixing water with a gas such as N2 or water vapor at the discharge nozzle. can be used.

DISCLOSURE OF THE INVENTION BASED ON DRAWINGS FIG. 1 shows an experimental apparatus prepared to confirm the cooling effect of the present invention. In this device, red-hot coke (2) is filled into an iron box (1), and the internal temperature is raised to 1ooo'.
c to bring about the same condition as inside a blast furnace, and water (I
Q /m1n), a mixture of water (I Q /m1n) and N2 gas (2Q/m1n), N2 gas (5i/m1n),
l1lin) and water vapor (5f/m1n) were individually blown in, and the cooling effect was examined using a plurality of thermometers (5) attached to the side wall of the box (1). Figure 2 shows the temperature measurement positions at that time. Nine thermometers were installed from A to I to measure temperatures.

The distance between the thermometers was 270 mm between thermometers, and 300 mm for all other thermometers.

FIG. 3 shows the temperature measurement results 10 minutes after the start of each cooling medium injection. From Figure 3, a cooling effect can be obtained with any cooling medium, and among them, the cooling effect can be obtained with only water and with a mixed cooling medium of water and N2 gas! It was found that the cooling effect was large and that cooling could be achieved over a wide range.

FIG. 4 is a schematic diagram showing an embodiment of the apparatus for carrying out the method of this invention, in which (10) is the blast furnace wall, (11) is the iron shell,
(12) is a stave cooler, (13) is a cooling medium injection nozzle, (14) is a cooling pipe, (15) is an on-off valve, (16) is a flow rate adjustment valve, (17-1) is a furnace thermometer, (17-2) is a steel shell thermometer, (17-3) is a stave thermometer, and (18) is a blow cover control relay.

The cooling medium injection nozzle (13) and the thermometer (17) are installed in the area where damage to the furnace wall is expected. As the thermometer, for example, the contact temperature S1 can be used. The flow rate adjustment valve (16) is controlled by the control relay (18) according to the measured temperature values of the furnace thermometer (17-1), the steel skin thermometer (17-2), and the stave temperature system (17-3). A valve opening command is given to the thermometer, and the blowing calendar is automatically controlled.

Function In the above device, water or a mixed cooling medium of water and N2 gas flows from the cooling pipe (14) to the WvI closing valve (15).
) and each flow rate adjustment valve (16), and is blown into the furnace from the cooling medium injection nozzle (13). The cooling medium blown into the furnace evaporates within the furnace, and the heat of evaporation generated at this time lowers the temperature of the atmospheric gas in the furnace and cools the furnace walls. At that time, the furnace thermometer (17-1) and the iron skin thermometer (17
-2) and the stave thermometer (17-3) measure the furnace wall temperature, and the measured value is input to the control relay (ia). The control relay determines the opening degree of each meteor adjustment valve (16) according to the input temperature, and sends a valve opening command to each flow rate adjustment valve to ensure that the appropriate amount of cooling medium is injected into the furnace. is blown into.

Therefore, the furnace wall is always cooled by an appropriate amount of cooling medium, and there is no possibility of furnace cooling due to insufficient furnace heat.

Moreover, no more deposits than necessary are generated on the furnace wall.

Example In a blast furnace with an internal volume of 2100 m', a mixed cooling medium of water and N2 gas was blown into the furnace using a device not shown in Fig. 4. After 30 minutes, the temperature inside the furnace increased from 1138°C to 835°C.
℃, and the shell temperature decreased from 350°C to 110'C, and it was confirmed in an actual blast furnace that the cooling effect was great. Note that the amount of water and N2 gas blown at this time was 0.5 m3/H and 1000 Nm3A, respectively, and they were blown from a total of 10 blowing holes in two stages, upper and lower.

Furthermore, Table 1 shows the results of blast furnace operation when the above cooling was performed in comparison with the case without cooling (Comparative Example 1) and the case without temperature measurement (Each Side 2).

As is clear from Table 1, in Comparative Example 1, stave pipe breakage and red heat occurred frequently, and in Comparative Example 2, the cooling medium was injected without monitoring the temperature inside the furnace, so there was a lot of damage in the furnace. Although a cooling medium was injected and damage to the furnace walls was alleviated, the temperature of the hot metal dropped extremely, so-called furnace cooling, and the number of times the iron was tapped decreased.

In contrast, in the example of the present invention, the blast furnace is operated by injecting a cooling medium while monitoring thermometers installed inside the furnace and in various parts of the furnace body, resulting in no cooling of the blast furnace and a significant reduction in stave pipe damage. did.

As explained in detail in Table 1 below, according to the method of the present invention, not only a large cooling effect can be obtained, but also cooling can be performed according to the temperature inside the furnace and the furnace wall, so damage to the furnace wall can be effectively prevented. This not only has a great effect on extending the life of the furnace, but also prevents furnace cooling and excessive production of deposits due to excessive cooling, which can greatly contribute to stabilizing blast furnace operations.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an experimental device for confirming the cooling effect of the present invention, FIG. 2 is an explanatory diagram showing temperature measurement positions in the same device, and FIG. 3 is a diagram showing experimental results using the same device.
FIG. 4 is a schematic diagram showing an example of an apparatus configuration for carrying out the method of this invention. DESCRIPTION OF SYMBOLS 11... Iron skin, 12... Stave cooler, 13... Cooling medium blowing nozzle, 14... Cooling piping, 15... Opening/closing valve, 16... Flow rate adjustment valve, 11-1. ...furnace thermometer, 17-2...iron shell thermometer, 17-3...stave thermometer, 18...injection amount control relay. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A hole is drilled in the wall of the blast furnace that penetrates into the furnace, and water or a cooling medium consisting of a mixture of water and cooling gas is blown into the furnace through the hole, and the inside of the furnace or the furnace wall near the through-hole is injected into the furnace. A method for cooling a blast furnace wall, the method comprising adjusting the amount of the cooling medium blown in according to the temperature.