KR20010035987A - Preventing apparatus of heat load increasing in blast furnace wall - Google Patents

Abstract

PURPOSE: An apparatus for restraining heat load of furnace wall of a blast furnace is provided to improve air permeability in a blast furnace by lowering pressure loss at front of a tuyere inside a blast furnace, and reduce heat load of furnace body by moving gas flow into the center of the blast furnace during combustion of pulverized coal. CONSTITUTION: The apparatus comprises a pulverized coal injection lance for injecting pulverized coal into a tuyere of a blast furnace, wherein an admission angle of the pulverized coal injection lance curves at an angle of 10 to 15 degrees so that the front end of the injection lance is positioned at area which is distanced 100 to 300 mm from the front end of the tuyere, and cooling devices installed at a joint area (19) with a tuyere of a blowing tube (17) to inside of which the pulverized coal injection lance is extended, wherein the cooling devices protect the forward arranged pulverized coal injection lance from heat of a high temperature in an apparatus for restraining heat load of furnace wall of a blast furnace comprising a pulverized coal injection lance injecting pulverized coal through a tuyere formed at lower part of the blast furnace.

Description

Blast furnace heat load suppression device {PREVENTING APPARATUS OF HEAT LOAD INCREASING IN BLAST FURNACE WALL}

The present invention relates to a blast furnace operation (hereinafter referred to as 'blast furnace'), more specifically in the operation of high pulverized coal operation (operation to increase the use of ore compared to the coke consumption) in order to secure air permeability, which is the most important indicator for determining the blast furnace internal situation. In order to ensure smooth gas flow and air permeability in the center, middle and furnace walls of the blast furnace, the operation of high pulverized coal can be carried out stably in high pulverized coal operations. The present invention relates to a furnace wall heat load suppression device due to internal pulverized coal combustion focus movement.

In general, the blast furnace operation stores iron ore and coke transported from raw materials, sintering and coke processes, which are the preliminary processes of the blast furnace process, in the raw material storage tank of the blast furnace, and after weighing the appropriate amount with the weighing machine according to the operation degree and use plan of the blast furnace, Put into the hopper installed and pressure in the hopper at a pressure slightly higher than the pressure in the blast furnace (+ 0.05㎏ / ㎠), and then controlled by the tilt angle of each notch through the charge distribution chute installed in the blast furnace to be uniformly loaded into the blast furnace The coke is charged uniformly in the radial direction in the order of charging coke (particle size 35 to 55 mm), opposing light (particle size 12 to 50 mm) and small particle light (particle size 5 to 12 mm). It is charged in the blast furnace 10 as shown in FIG. 1 to induce a charge distribution shape for maximizing breathability and gas utilization with a stable gas flow at the top. Eojinda.

The blast furnace 10 is provided with a tap hole 8 at a lower side thereof, and a plurality of air vents 12 for injecting pulverized coal and oxygen are installed thereon, and a core in which fuel and raw materials charged in the blast furnace 10 are stacked. The combustion zone 9 is formed near the tuyere 12 in contact with the section 13, and the blast furnace operation is performed while forming the softening fusion zone 11 below the charging line on the upper part of the core part 13 of the blast furnace 10. Is done.

At this time, the iron ore is reduced by blowing high temperature hot air at about 1100 ° C. through the 34 tuyere 12 below the blast furnace, while the tuyere extends into the blower tube 17 installed in the tuyere 12 as shown in FIG. 2. The pulverized coal is blown in place of the coke, which is the main fuel, through the pulverized coal injection lance 15 which blows the pulverized coal supplied from the pulverized coal supply pipe 15a into the blast furnace together with the oxygen supplied through the oxygen supply pipe 16.

As such, the furnace is generally formed in the bottom of the blast furnace in order to melt the ore by using the hot air, although there is a slight difference depending on the size of the blast furnace is formed of pure copper materials for blowing air (12) to protect the tuyere In order to supply the cooling water.

The pulverized coal blowing lance 15 is also provided in the air vent 12 for blowing air, and as shown in FIG. 3, the front end of the pulverized coal blowing lance 15 is located at 550 mm in front of the front end of the air vent to supply pulverized coal. In case of deformation or deflection of pulverized coal injection lance, the location where pulverized coal is blown is blown in one direction instead of being blown into the center of the funnel. Since the site where the pulverized coal meets the oxygen is located in front of the tuyere, the combustibility of the pulverized coal is deteriorated.

In order to solve such a problem, conventionally, it has been made to cope with the damage to the windball by increasing the cooling water supply amount and increasing the water supply pressure to strengthen the cooling capacity. At the time of contact, there was a problem that could not prevent damage to the airball at all.

In addition, in order to improve the combustibility in order to increase the pulverized coal injection ratio, pure oxygen is injected together with the pulverized coal for operation, but the limit of the oxygen supply and the infinite supply of expensive oxygen are not achieved, thereby improving the combustibility of pulverized coal by oxygen supply. There is a limit to this.

Accordingly, the present invention has been made to solve the problems of the prior art as described above, and by advancing the tip position of the pulverized coal blown lance at a certain distance from the tip of the tuyere, induces a decrease in pressure loss at the tip of the tuyere inside the blast furnace due to the lance earthquake resistance. At the same time, it improves the ventilation in the furnace and prevents damage caused by abrasion of the inner surface of the tuyere when increasing the amount of pulverized coal injection, and prevents the growth of deposits due to the melting of coke ash on the inner surface of the tuyere. It is an object of the present invention to provide a furnace wall heat load suppression device by pulverizing internal pulverized coal combustion focus movement that can perform stable operation by solving the problem.

1 is a view showing a blast furnace that is generally used,

2 is a detailed view of the blast furnace tuyere portion,

3 is a view illustrating a pulverized coal blowing lance disposed in a conventional blast furnace tuyere,

4 is a view showing the configuration of the blast furnace furnace wall portion heat load suppression apparatus of the present invention,

5 is a view showing a change in the ventilation resistance index according to the change in the amount of pulverized coal injection in the present invention and the conventional example,

6 is a view showing the temperature change of the blast furnace Bosch part according to the change in the amount of pulverized coal injection in the present invention and the conventional example.

Explanation of symbols on the main parts of the drawings

10: blast furnace 12: balloon

15: Pulverized coal injection lance 17: Blower pipe

19: Air pipe joint 21: Cooling water supply pipe

22: Cooling water jacket 23: Cooling water discharge pipe

In order to achieve the above object, in the present invention, a blast furnace furnace wall heat load suppression device comprising a pulverized coal blowing lance for blowing pulverized coal through a tuyere formed in the lower part of the blast furnace, the pulverized coal blowing lance for blowing pulverized coal into the blast furnace tuft A cooling mechanism is arranged so that the tip of the blown lance is positioned at a portion of 100 to 300 mm from the tip of the blowhole at 10 to 15 degrees, and the pulverized coal blown lance is protected from high heat at the junction with the blowhole of the blowpipe through which the pulverized coal blown lance extends inward. It provides a blast furnace furnace wall heat load suppression device characterized in that the installation.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing preferred embodiments.

Before explaining the present invention, the change in the blast furnace in the blast furnace when a large amount of pulverized coal is blown, the breathability is lowered due to the smaller thickness of the coke layer, the furnace heat load is increased at the lower part of the furnace, and the furnace is deposited by unburned coal. Deterioration of aging, such as low air permeability and poor liquid permeability, occurs. To improve this, the gas resistance at the center of the blast furnace is properly adjusted by reducing the ventilation resistance at the bottom of the blast furnace, and the gas temperature at the middle of the blast furnace is appropriately adjusted. Gas temperature control of the furnace wall is required.

Therefore, in the present invention, as shown in FIG. 4, the tip portion of the pulverized coal injection lance 15 charged into the tuyere 12 is 100 to 300 mm away from the tip of the tuyere 12 so as to reduce pressure loss at the tuyere. If the tip of the pulverized coal injection lance is moved inward from the tip of the tuyere, it is preferable to inject pulverized coal, but if the pulverized coal injection lance is 100 mm or less considering the material and the vent material, the pulverized coal injection lance is excessively inside the furnace. When the tip is heated by the high temperature part of the blast furnace internal combustion zone, melting loss and deformation of the pulverized coal injection lance 15 are severely generated, causing air holes to be broken and difficulty in blowing pulverized coal, and when the distance is separated by 300 mm or more, It is not possible to reduce the furnace wall heat load in the lower part, which causes excessive furnace wall heat load and fluctuation of furnace body temperature. And limited as described above, a most preferred location is arranged to move 220㎜.

Meanwhile, in the present invention, when the pulverized coal injection lance 15 is placed forward, the entrance angle of the lance 15 is reduced to 10 to 15 degrees so that the lance tip is located at the center of the windball to prevent bias of the lance tip and the most ideal in the furnace. Adjust to form a combustion zone.

In addition, in the present invention, as the pulverized coal injection lance 15 is moved close to the high temperature portion of the furnace, the pulverized coal blown tube 17 through which the pulverized coal injection lance 15 extends to prevent damage to the lance is exposed to high temperature. On the outer circumferential surface of the joint portion 19, a cooling mechanism composed of a cooling water supply pipe 21, a cooling water jacket 22, and a cooling water drain pipe 23 is installed in the circumferential direction to dissipate heat received by the pulverized coal injection lance 15. The combustion heat prevents the temperature of the blower pipe joining portion from rising to damage the pulverized coal injection lance 15.

As described above, in the present invention, the pulverized coal injection lance is advanced to the tip of the tuyere to move the pulverized coal combustion focus into the tuyere to reduce the pressure loss at the tuyere, as well as to move the combustion focus to the furnace center side to improve the combustibility of the pulverized coal and the furnace wall. The heat load of the blast furnace furnace wall is reduced by reducing the flow rate of the gas which is hot to the furnace and increasing the gas flow rate to the center portion.

5 and 6 show the in-vehicle breathability and the temperature of the furnace body Bosch part in comparison with the conventional case when the blast furnace pulverized coal blowing operation is performed through the apparatus of the present invention, as shown in FIG. It can be seen that is improved, and as can be seen from FIG. 6, it can be seen that the furnace body heat load can be suppressed because the furnace body Bosch temperature decreases.

Therefore, according to the present invention as described above, it is possible to reduce the pressure loss in front of the blast furnace internal tuyere to improve the in-vehicle ventilation, and to reduce the furnace heat load by moving the gas flow to the furnace center during pulverized coal combustion.

In addition, when the amount of pulverized coal blown is increased, it is possible to prevent breakage due to wear on the inner surface of the tuyere, and to prevent the growth of the melt by melting ash in the tuyere. It can be.

Claims (1)

As a blast furnace furnace wall heat load suppression device comprising a pulverized coal injection lance 15 for blowing pulverized coal through the tuyere 12 formed in the blast furnace, The pulverized coal injection lance 15 for injecting pulverized coal into the blast furnace is arranged so that the injection lance tip is positioned at a portion 100 to 300 mm from the tip of the tuyere 12 with an entrance angle of 10 to 15 degrees. Blast furnace furnace wall heat load suppression device, characterized in that cooling mechanisms (21, 22, 23) are provided to protect the pulverized coal injection lances, which are arranged forward, at the joint portion (19) of the blower pipe (17) extending inwardly from high heat. .