KR101633210B1 - Sintering machine ignition apparatus and sintering machine - Google Patents

Abstract

A fuel gas passage extending in the width direction of the pallet of the sintering machine, an air passage extending to both sides of the fuel gas passage, a flow passage for the fuel gas from the fuel gas passage, A burner provided with a plurality of pairs of nozzle holes spaced apart along the longitudinal direction of the fuel gas passageways and the air passageways opened in a direction in which the jet streams of the combustion air from the air passageways join; And the burner is a burner which is formed by welding a stainless steel plate to the burner hood.

Description

TECHNICAL FIELD [0001] The present invention relates to a sintering machine and a sintering machine,

The present invention relates to an ignition device for use in a sintering machine for producing sintered ores and a sintering machine equipped with the ignition device.

Generally, an ignition device for a sintering furnace for producing sintered ores is a device for burning a fuel such as a heavy oil, a coke oven gas or a mixture gas of coke oven gas and blast furnace gas from the burner, and air To form a combustion flame, and heating the sintering raw material layer with such a combustion flame to burn the coke in the raw material sintering layer.

Fig. 6 shows a sintering machine in which the ignition device according to the present invention is installed. In the figure, reference numeral 1 denotes a pallet, 2 denotes a wind box, and 3 denotes an ignition apparatus. The ignition apparatus mainly comprises an ignition furnace 3a and a burner 3b. layer hopper, and 5 denotes a raw material hopper.

The ignition device disclosed in Japanese Patent Application Laid-Open No. 59-200183 (Patent Document 1) includes a fuel gas passage and a combustion air passage extending in the width direction of the pallet of the sintering machine, a fuel gas supplied from these passages, And a burner provided with a plurality of nozzle holes spaced along the longitudinal direction of the respective passages, the plurality of nozzle holes being opened in a direction in which the jet streams of the combustion air are merged with each other. Patent Document 1 discloses a technique for shortening the flame by injecting fuel gas and air so as to intersect with a nozzle hole of a small diameter, thereby remarkably improving energy loss. However, as in Patent Document 1, when the combustion chamber is small and the burner height is low, there is an advantage of suppressing the amount of fuel used because the furnace body heat dissipation is small. On the other hand, when the sintering raw material layer is heated, There is a possibility that the burner body is damaged by the heat of the flame itself.

On the other hand, Japanese Unexamined Patent Publication No. 4-28826 (Patent Document 2) discloses that since the coefficient of linear expansion of the burner tip of the heat resistant cast steel is larger than that of the soft steel, the burner tip has a large elongation at the time of operation, Discloses a technique for providing a thermal expansion absorbing value by dividing the burner tip into a plurality of pieces in the width direction of the pellet so as to prevent cracking accompanying expansion and shrinkage. Patent Document 2 discloses that the frame is shortened by injecting the fuel gas and the air at right angles to each other and that the nozzle hole diameter is gradually increased at the end portion of the vent hole at both ends of the pallet than at the center portion, Is disclosed.

However, due to factors such as an abrupt stop of the sintering machine, thermal deformation and cracking of the burner nozzle still occur under a use environment in which the operation-stoppage is repeated frequently, and countermeasures against the shortening of the life of the burner are insufficient.

Patent Document 1: JP-A-59-200183 Patent Document 2: JP-A-4-28826

An object of the present invention is to provide an ignition device which is resistant to thermal stress even in a use environment where frequent operation-stopping is repeated, and to extend the service life of the ignition device of the sintering machine and lower the maintenance frequency.

The features of the present invention to solve the above problems are as follows.

[1] A fuel gas passage extending in a width direction of a pallet of a sintering machine, and an air passage extending to both sides of the fuel gas passage, A plurality of pairs of nozzle holes opened in the direction in which the injected flow of the fuel gas from the fuel gas passageway and the air flow for combustion from the air passageway are merged is formed in the longitudinal direction of the fuel gas passageway and the air passageway And a burner hood covering the combustion atmosphere below the nozzle hole, wherein the burner is a burner that is formed by welding a stainless steel plate.

[2] The ignition device of the sintering machine according to [1], wherein the jet stream of the fuel gas and the jet stream of the combustion air converge at an angle of 30 degrees or more and 60 degrees or less.

[3] The igniter for a sintering machine according to [1], wherein the burner comprises a burner body and a burner tip, and the burner body and the burner tip are integrally structured.

The plurality of pairs of nozzle holes may include a fuel gas nozzle hole and an air nozzle hole. The fuel gas nozzle hole may be provided on the center side of the burner and open in a direction toward the outside, The ignition device of the sintering machine according to [1], wherein the ignition device is opened to the outside in the inside of the burner.

[5] An ignition device for a sintering machine according to any one of [1] to [4], wherein a plurality of gaps for absorbing heat elongation are provided in the width direction of the pallet of the sintering machine, Wherein an end of the adjacent burner is closely contacted by thermal expansion.

According to the present invention, it is possible to provide an ignition device for a sintering machine having uniform ignition strength in the width direction of the sintering machine pellet and having a low fuel unit as an ignition device, which is resistant to thermal stress even under a use environment in which operation- Device can be provided.

1 is a sectional view of an ignition device according to the present invention.
2 is a front view showing a part of the sintering machine pellet and the ignition device as a section.
3 is a cross-sectional view of a conventional ignition device.
4 is a graph showing the relationship between the distance from the burner tip to the surface of the sintering raw material layer and the flame temperature.
5 is a view showing a nozzle arrangement of the burner tip portion.
6 is a schematic configuration diagram of a sintering machine in which the apparatus of the present invention is installed.

It is necessary to divide the burner main body and the burner nozzle from the restriction of the material and the processing method of the conventional heat resistant main forced burner. By the repeated thermal deformation of the flange surface connecting the burner main body and the burner nozzle, Further, deterioration of the packing, disconnection of the fuel gas and combustion air by the cutting occurred. The inventors of the present invention have conducted intensive studies and have found that the burner is made of stainless steel in which the burner main body and the burner nozzle are integrally structured in the heat-resistant main mandrel subdivision so that even in a use environment where operation- It is possible to provide an ignition device.

Table 1 shows the results of comparing the effects of material changes. Since the material of the burner is changed from the heat resistant cast steel to the stainless steel material having the integral structure of the burner nozzle and the burner nozzle, the fuel leakage due to the distortion of the flange portion is eliminated. By reducing the thickness of the burner and the nozzle, the residual stress and the distortion of the burner were reduced. As a result, it became a burner that can be used for a long period of time even in a use environment in which the operation-stoppage is frequently repeated.

[Table 1]

As a result of examining the angle at which the jet streams of the fuel gas and the combustion air are merged with each other, it is possible to lower the temperature of the nozzle section by setting the angle to 60 degrees or less, I found out. This will be described below with reference to Table 2 and FIG.

Table 2 shows the results of evaluating the durability of a test burner furnished with an experimental burner having a burner width of 500 mm. An iron plate was laid on the opposite surface of the burner in the furnace, and the burner was configured to receive radiant heat from below. The temperature of the steel plate was raised to 1300 ° C, which is equivalent to that of a normal sintering machine, and to 1350 ° C under the condition that the sintering machine was changed, and the temperature was maintained for 30 minutes. Respectively.

Thermal deformation is eliminated by making the burner a welded integral structure of a comparatively thin stainless steel plate in the conventional heat-resistant main-force splitting structure. In a normal sintering machine operation, the surface temperature of the sintering raw material layer (corresponding to the temperature in the furnace during the test) is 1300 DEG C, and cracking can be prevented by making the burner material stainless steel within the normal operating range. Even when the temperature in the furnace rises to 1350 DEG C due to the fluctuation of the sintering machine operation, the joining angles of the fuel gas and the blowing air of the combustion air are joined at an acute angle of 60 DEG and 40 DEG from the conventional 90 DEG, It can be seen that the frequency of cracking of the nozzle portion can be lowered. As shown in Table 2, the durability was improved at six times at 60 degrees and ten times at 40 degrees, while cracking occurred at three times at 90 degrees. That is, it has been found that the effect of preventing the occurrence of cracks in the nozzle portion can be obtained because the temperature of the nozzle portion can be lowered by making the angle at which the injected streams of the fuel gas and the combustion air join each other to 60 degrees or less.

[Table 2]

The relationship between the distance from the burner nozzle and the flame temperature is shown in Fig. It is necessary to lengthen the flame portion having a temperature of 1300 占 폚 or more and to lengthen the distance between the burner and the heating surface as the angles at which the fuel gas and the blowing air of combustion air join each other at an acute angle. The temperature from the burner nozzle to 100 mm is greatly lowered in the range of 30 degrees to 60 degrees at which the jet streams flow to each other, which is preferable for reducing the temperature of the nozzle portion and preventing cracking of the nozzle portion.

When the merging angle of the blown streams is less than 30 degrees, the burner flame length becomes longer than 850 mm, the burner hood becomes larger, and the energy loss increases, which is not preferable.

It is preferable that a plurality of burners formed by welding the stainless steel plate of the present invention are arranged in the width direction of the sintering machine. By arranging a plurality of burners in the width direction, the combustion conditions in the width direction of the sintering machine can be individually changed and adjusted in view of the temperature distribution at the time of operation, and the operating conditions such as changing the distribution of the raw material layer thickness are changed The temperature distribution in the sea-island width direction can be adjusted.

In the present invention, it is preferable to provide a thermal expansion absorption value between a plurality of burners. The size of the thermal expansion value is such that when the end portion of the adjacent burner is closely contacted with the end portion of the adjacent burner in the inner temperature atmosphere due to operation ignition, ambient air is sucked from this expansion value during operation and disturbance occurs in the ignition frame There is no.

Further, since the burner is made thinner by using the stainless steel plate as the burner, the burner support structure can be simplified, and the installation work is also facilitated.

Hereinafter, an embodiment of the present invention will be described.

Fig. 2 shows a part of the sintering machine pellet and the ignition device as a section. Bb is the burner body, Bt is the burner tip, F is the flame, and L is the distance from the burner tip to the surface of the sintering raw material layer. The fuel gas supply pipe 8 and the air supply pipe 9 are provided over the entire width of the pallet and a plurality of burners having the fuel gas pipe 6 and the combustion air pipe 7 are connected to the fuel gas supply pipe 8, (9) so as to be substantially in parallel with each other. The gas pipe 6 and the gas supply pipe 8 communicate with each other through the short pipe 10 and the air pipe 7 and the air supply pipe 9 communicate with each other through the short pipe 11. The fuel gas supply pipe 8 and the air supply pipe 9 are supported by a girder 26.

A plurality of nozzle holes 20, 20 ', 21 and 21' corresponding to the fuel gas supply pipe 8 and the air supply pipe 9 of the burner are formed in the lower part of the burner, And a plurality of rows are arranged in the tube axis direction.

The fuel gas nozzle holes 20 and 20 'are open in both the outward direction and the air nozzle holes 21 and 21' are opened inward in the opposite direction, and the fuel gas nozzles 21 and 21 ' And the air nozzles 20 (20 ') are merged with each other to shorten the frame.

1 is a sectional view of an ignition apparatus according to the present invention. As described above, the burner body and the burner tip are integrally formed. In this drawing, COG is exemplified as a fuel gas. In the drawing,? Represents the angle at which the injected streams of the fuel gas and the combustion air join with each other. At this time, it is advantageous to reduce the energy loss by shortening the burner flame length and decreasing the interval between the burner and the upper surface of the sintered raw material layer in the pellet shape. On the other hand, if the angle in which the jetting directions merge with each other is small, the length of the burner flame becomes long, but the temperature of the nozzle part is lowered, and the problem of cracking or thermal deformation of the nozzle part does not occur easily. From the above, it is preferable that the angle at which the jetting directions mutually join is 30 degrees or more and 60 degrees or less. Further, in order to reduce the thermal influence, it is more preferable that the surface of the burner other than the burner front end where the nozzles are arranged is covered with the refractory heat insulating material.

From both sides of the nozzle holes 21 and 21 ', a burner hood 24a covering the combustion atmosphere below the nozzle hole extends. By downsizing the burner hood and surrounding the high temperature range, it is possible to reduce the energy loss and to operate the fuel burner unit at a low fuel source unit.

The hole diameters and pitches of the nozzle holes 20, 20 ', 21 and 21' should be appropriately adjusted in accordance with the kind of the fuel gas, the flow rate of the fuel gas and the air, but the hole diameter is 5 to 30 mm, 40 mm is preferable. When the pitch is too wide, a portion having a low temperature is generated between the flames, and a problem occurs in that the sintered ores are not uniformly combusted.

The fuel gas preferably has a calorific value of 2 to 25 kcal / Nm 3. For example, M gas (mixed gas of blast furnace gas and coke oven gas), C gas (coke oven gas), liquefied natural gas, propane gas and the like which are commonly used in steelworks can be used. When the calorific value of the fuel gas is less than 2 kcal / Nm 3, the fuel consumption is increased, which is uneconomical. It is more preferable to use a fuel gas having a calorific value of 15 kcal / Nm 3 or less in terms of the self-cooling function of cooling the gas / air for combustion from the inside.

In order to optimize the nozzle lifetime and arrangement of the burner, it is necessary to re-manufacture the nozzle tip from the frame in the conventional heat resistant cast steel. However, because of the welded structure of the stainless steel plate, Can be made inexpensively and in a short period of time, and even if the burner is cracked or cracked, it is possible to repair easily by welding. Further, if the thermal deformation is slight, since a thin stainless steel plate is adopted, it can be reused in short-time maintenance by correcting thermal deformation.

It is preferable to adjust the pore diameters in accordance with the distribution of the width direction passing air volume of the sintering machine bed from the viewpoint of uniform heating. However, if the fuel gas and the air flow rate are adjusted for each of the plurality of burners arranged, . In addition, by observing the temperature distribution at the time of operation, the combustion condition can be changed and adjusted for each burner, and even if the operating conditions such as the distribution of the raw material layer thickness are changed, the temperature distribution in the width direction can be adjusted.

Further, each of the burners may be configured to be changeable in vertical angle. The contact area between the surface of the sintering raw material layer and the front end of the frame can be made variable by raising and lowering the respective burners, thereby making it possible to improve the accuracy of the uniform ignition. By bringing the burner up and down according to the change of the sintering raw material layer thickness, the change of the pallet speed, the raw material property, the moisture content in the raw material, etc., remarkable effects such as improvement of the quality of the sintered ores,

<Examples>

In a sintering plant having a sintering output of 11000 t per day, a stainless steel plate (SUS 316) was welded to a burner in an ignition burner of a heat-resistant cast steel. A heat-resistant main burner was a burner integrally molded over the entire width of the sintering machine of 3950 mm. However, burners obtained by welding a stainless steel plate were arranged by arranging five 800 mm-wide burners in the transverse direction of the sintering machine pallets.

The angle of the spouting flow of the fuel gas and the combustion air was 90 degrees in the burner of the heat resistant cast steel, but changed by 40 degrees in the burner of the stainless steel plate.

M gas was used as the fuel gas, and the surface temperature of the sintering raw material layer was adjusted to 1300 캜.

As a result of the operation by the above ignition device, it was necessary to correct heat distortion and repair the cracks six times / year when using the heat resistant main forced burner, and the maintenance time was 48 hours / After the change, only one year / year of thermal deformation correction was performed. As a result, the maintenance time could be shortened to 40 hours / year, and the maintenance frequency and maintenance time could be significantly reduced. The maintenance time is a maintenance time including maintenance of the sintering equipment other than the burner.

Bb; Burner body Bt; Burner tips
F; flame
L; Distance from the tip of the burner to the surface of the sintered raw material layer
One; Pallet 2; Wind box
3; Ignition device 3a; By ignition
3b; Burner 4; Hopper for upper light
5; Raw hopper 6; Fuel gas pipe
7; Combustion air pipe 8; Fuel gas supply pipe
8a; A central flow passage 9 in the fuel gas pipe; Air supply pipe
9a; The tubular passages 10, 11 of the air pipe; Short tube
17,17 '; flange
20,20 ', 21,21'; Nozzle hole
24 (24a, 24b); Burner hood 26; duty

Claims (5)

A fuel gas passage extending in the width direction of the pallet of the sintering machine,
An air passage extending to both sides of the fuel gas passage,
And a plurality of pairs of nozzle holes opened in the direction in which the jet stream of the fuel gas from the fuel gas passage and the jet stream of the combustion air from the air passage join with each other, A burner provided in a direction spaced apart from the burner,
And a burner hood covering the combustion atmosphere below the nozzle hole,
Wherein the burner is a burner formed by welding a stainless steel plate, the burner body and the burner tip, and the burner body and the burner tip are integrally formed by welding. The method according to claim 1,
Wherein the injected stream of the fuel gas and the injected stream of the combustion air are merged at an angle of 30 degrees or more and 60 degrees or less. delete The method according to claim 1,
Wherein the multiple pairs of nozzle holes comprise a fuel gas nozzle hole and an air nozzle hole,
The fuel gas nozzle hole is provided on the center side of the burner, and is opened in a direction toward the outside,
And the air nozzle hole is opened to the outside of the burner in the inward direction. The ignition device for a sintering machine according to any one of claims 1, 2, and 4 is arranged in the width direction of the pallet of the sintering machine by arranging a plurality of gaps for absorbing heat elongation, And an end portion of the adjacent burner is closely arranged by thermal expansion.

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