JP2013130368A - Sintering machine, and gaseous fuel supply method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sintering machine capable of producing sintered ores of high strength and high quality at a high yield even if there occurs defective ignition at a raw material loading layer surface layer in pallet width direction of the sintering machine.SOLUTION: A sintering machine includes: a pallet which cyclically moves; a raw material supply device which forms a sintering material loading layer; an ignition furnace which ignites the loading layer; a wind box arranged below the pallet; a gaseous fuel supply device which is arranged on a downstream side of the ignition furnace, dilutes the gaseous fuel to a combustion lower limit concentration or less, and supplies it into the loading layers; a hood which encloses the gaseous fuel supply device; an ignition failure region detection device which measures temperature distribution in pallet width direction of a raw material loading layer surface layer on the ignition furnace output side, for identifying an ignition failure region in the pallet width direction; and a gaseous fuel supply amount control device which increases the gaseous fuel supply amount at the ignition failure part.

Description

  The present invention relates to a downward suction type Dwytroid (DL) type sintering machine for producing high strength and high quality sintered ore and a method for supplying gaseous fuel in the sintering machine.

  Sinter ore, which is the main raw material of the blast furnace ironmaking method, is generally manufactured through a process as shown in FIG. The raw materials for sintered ore include iron ore powder, iron mill recovered powder, sintered ore sieving powder (returning), CaO-containing auxiliary raw materials such as limestone and dolomite, granulation aids such as quick lime, coke powder and anthracite It is. These raw materials are cut out from each of the hoppers 1. Thereafter, an appropriate amount of water is added to the cut out raw material using a drum mixer 2a, 2b and the like, mixed and granulated to obtain a sintered raw material which is pseudo particles having an average diameter of 3.0 to 6.0 mm. On the other hand, on the great of the endless moving pallet 8, the returned ore that has been sized to less than 5.0 mm is cut out from the floor hopper 4 and laid to form a floor layer. Thereafter, the above-mentioned sintering raw material is charged onto the sinter from a surge hopper 5 disposed on the sintering machine via a drum feeder 6 and a cutting chute 7, and the cut-off plate 12 causes unevenness on the surface of the charging layer. And a charging layer 9 of a sintering raw material, also called a sintering bed, is formed. The thickness (height) of the charging layer is usually around 400 to 800 mm. Thereafter, in the ignition furnace 10 installed above the raw material charging layer 9, the carbon material in the surface layer of the charging layer 9 is ignited and through a wind box 11 disposed under the pallet 8. By sucking air downward, the carbonaceous material in the charging layer is sequentially combusted, and the sintered raw material is combusted and melted by the combustion heat generated at this time to obtain a sintered cake. The sintered cake obtained in this way is then crushed and sized, and a product sintered ore composed of agglomerates of 5.0 mm or more is used, and agglomerates of less than 5.0 mm are returned to ore.

  In the manufacturing process, the carbonaceous material in the surface layer of the charging layer ignited by the ignition furnace 10 is continuously burned by the air sucked downward from above through the charging layer by the wind box 11, and the combustion zone As shown in FIG. 2, the gradual progresses gradually toward the lower layer as the pallet 8 moves. As the combustion progresses, the moisture contained in the sintering raw material particles of the charging layer is vaporized by the combustion heat of the carbonaceous material, sucked downward, and in the lower sintering raw material that has not yet risen in temperature. To form a wet zone. When the moisture concentration exceeds a certain level, voids between the sintered raw material particles, which are suction gas flow paths, are filled with moisture, and the ventilation resistance increases. In addition to the wet zone, the melted portion required for the sintering reaction that occurs in the combustion zone is also a factor that increases the ventilation resistance.

The production amount (t / hr) of a sintering machine is generally defined by sintering production rate (t / hr · m ² ) × sintering machine area (m ² ). Therefore, the production volume of the sintering machine includes the width and length of the sintering machine, the thickness of the raw material deposition layer (the thickness of the charging layer), the bulk density of the sintering raw material, the sintering (combustion) time, the yield, etc. It depends on. In order to increase the production of sintered ore, the air permeability (pressure loss) of the charging layer is improved to shorten the sintering time, or the cold strength of the sintered cake before crushing is increased. It is considered effective to improve the retention.

  FIG. 3 shows the inside of the charging layer when the combustion (flame) front moving through the charging layer having a thickness of 600 mm is at a position of about 400 mm (200 mm from the surface of the charging layer) on the pallet of the charging layer. This shows the pressure loss and temperature distribution. The pressure loss distribution at this time indicates that about 60% is in the wet zone and about 40% is in the combustion / melting zone.

FIG. 4 shows the temperature distribution in the charging layer at the time of high production and low production of sintered ore. In this figure, the time during which the raw material particles begin to melt at a temperature of 1200 ° C. or higher (hereinafter referred to as “high temperature region holding time”) is t _{1 for} low production and t ₂ for high production. It represents. When high production is to increase the moving speed of the pallet, the high temperature zone holding time t _2, it is shorter than the t ₁ when the low production. When the high temperature region holding time is shortened, the firing becomes insufficient, the cold strength of the sintered ore is lowered, and the yield is lowered. Therefore, in order to increase the production volume of the sintering machine, even in short-time sintering, it is necessary to ensure sufficient holding time in the high temperature range, increase the cold strength of the sintered ore, and maintain and improve the yield. It is important to plan. In general, SI (shutter index) and TI (tumbler index) are used as indices representing the cold strength of sintered ore.

  FIG. 5A shows the progress of sintering in the charging layer on the pallet, FIG. 5B shows the temperature distribution (heat pattern) in the sintering process in the charging layer, and FIG. Shows the yield distribution of the sintered cake. As can be seen from FIG. 5B, the temperature of the upper portion of the charging layer is less likely to rise than the lower layer portion, and the high temperature region holding time is also shortened. Therefore, in the upper part of the charging layer, the combustion melting reaction (sintering reaction) becomes insufficient, and the strength of the sintered cake is lowered. Therefore, as shown in FIG. It is a factor that causes a decline in

  In view of these problems, several techniques for maintaining the upper portion of the charging layer at a high temperature have been proposed. For example, Patent Document 1 discloses a technique for injecting gaseous fuel onto the charging layer after ignition of the charging layer upper layer. However, in this technique, the type of gaseous fuel (combustible gas) is unknown, but a high-concentration gas is supplied as it is. Moreover, since the amount of the carbon material is not reduced when the combustible gas is blown, the inside of the sintered layer becomes a high temperature exceeding 1380 ° C. For this reason, this technique cannot sufficiently enjoy the effects of improving cold strength and yield. Moreover, this technique has a high risk of causing a fire due to burning of the combustible gas in the upper space of the sintering bed when the combustible gas is injected immediately after the ignition furnace, and has not been put into practical use.

  Patent Document 2 also discloses a technique of adding a combustible gas into the air sucked into the charging layer after ignition of the upper layer of the raw material charging layer. In this technique, it is said that it is preferable to supply a combustible gas of about 1 to 10 minutes after ignition. However, in the surface layer portion immediately after ignition, red hot sintered ore remains, and depending on the supply method Has a high risk of fire due to combustion of combustible gas. Although there are few specific descriptions, when burning in the sintered zone, the air permeability is further deteriorated due to the temperature rise and thermal expansion caused by the combustion gas, so the productivity tends to be lowered. Has not reached. Moreover, since this technique also does not reduce the amount of carbonaceous material when blowing in combustible gas, the inside of the sintered layer becomes a high temperature exceeding 1380 ° C. For this reason, not only can the cold strength of the sintered ore be improved and the yield can be sufficiently improved, but also the obtained sintered ore will have poor reducibility.

  Further, in Patent Document 3, in order to make the inside of the sintering raw material charging layer a high temperature, a hood is disposed above the charging layer, and a mixed gas of air and coke oven gas is passed through the hood at a position immediately after the ignition furnace. It is disclosed that it blows in. However, this technique also has a high temperature exceeding 1380 ° C. in the combustion melting zone in the sintered layer, so that the effect of coke oven gas blowing cannot be enjoyed and combustible mixed gas burns in the upper space of the sintering bed. There is a risk of fire and is not put into practical use.

  Patent Document 4 discloses a method in which a low-melting-point solvent, a carbon material, and a combustible gas are simultaneously blown at a position immediately after the ignition furnace. However, this method also has a high risk of causing a fire in the upper space of the sintering bed because the flammable gas is blown in the state where the flame still remains on the surface of the charging layer, and the width of the sintering zone is sufficiently wide. Therefore, the effect of inflammable gas blowing cannot be fully enjoyed. Furthermore, since a large amount of low melting point solvent is added, excessive melting occurs in the upper layer of the charging layer, and the pores that become air flow paths are blocked and the air permeability is deteriorated, resulting in a decrease in productivity. . Therefore, this technology has not been put into practical use until now.

As described above, none of the conventional techniques proposed so far has been put into practical use. Therefore, the development of a combustible gas blowing technique that can be implemented has been eagerly desired.
Therefore, as a technique for solving the above-mentioned problems, the applicant, in Patent Document 5, disclosed various gaseous fuels diluted below the lower combustion limit concentration from above the sintering material charging layer deposited on the pallet of the sintering machine. A method is proposed in which either one or both of the maximum attained temperature and the high temperature region holding time in the charging layer are adjusted by supplying, introducing into the charging layer, and burning.

According to the technique of Patent Document 5, the gaseous fuel diluted to a predetermined concentration is supplied (introduced) into the charging layer and burned at a target position in the charging layer in the downward suction type sintering machine. By supplying gaseous fuel, it is possible to properly control the maximum temperature and holding time during combustion of the sintered raw material, and the cold strength of the sintered ore is likely to be lowered due to insufficient heat. It is possible to perform an operation that increases the strength of the sintered ore not only in the upper layer part but also in any part below the middle part of the charging layer. In addition, this technique can reduce the amount of carbonaceous material added that corresponds to the amount of heat of the gaseous fuel to be supplied, and thus is effective not only in reducing raw material costs but also in reducing CO ₂ emissions.

  By the way, when producing sintered ore using a downward suction type sintering machine, the carbon material in the surface layer of the raw material charging layer charged in the pallet is ignited in an ignition furnace for combustion and melting. A band is formed, and this combustion / melting zone moves from the upper layer to the lower layer of the raw material charging layer, whereby sintering proceeds. Therefore, in the downward suction type sintering machine, in order to uniformly sinter the sintered raw material charged (deposited) in the pallet, the ignition to the raw material charging layer is performed in the pallet width direction (pallet traveling direction). It is important to ignite uniformly in a direction perpendicular to the direction. If ignition failure occurs in the direction of the pallet width, the combustion of the carbonaceous material in that part will be delayed and the amount of heat will be insufficient, and it will not be possible to secure the maximum temperature and holding time during the sintering process. There is a possibility that the yield and productivity may decrease due to the decrease. In particular, when a sintering operation for supplying gaseous fuel is performed, the influence of ignition failure is increased because the carbonaceous materials are reduced.

  As for the ignition furnace for uniformly igniting the surface layer of the raw material charging layer, for example, techniques of Patent Documents 6 to 8 are disclosed.

Japanese Patent Laid-Open No. 48-18102 Japanese Patent Publication No.46-27126 JP-A-55-18585 Japanese Patent Laid-Open No. 5-311257 WO2007 / 052776 Japanese Examined Patent Publication No. 62-48129 Japanese Examined Patent Publication No. 62-23202 JP 2001-65824 A

  However, the sintering machine is generally operated without rest for 24 hours except during regular repairs, and even when the above-mentioned prior art ignition furnace is applied, the surface layer of the sintering raw material charging layer over a long period of time. There is a problem that it is difficult to continue to ignite uniformly.

  The present invention has been made in view of the above-described problems of the prior art, and the purpose thereof is even when ignition failure occurs in the raw material charging layer surface layer in the pallet width direction of the sintering machine, By providing a sintering machine that can stably produce high-strength, high-quality sintered ore with high yield by minimizing the impact and sufficiently securing the amount of heat necessary for sintering, It is to propose a method for supplying gaseous fuel in the sintering machine.

  The present invention developed to solve the above problems includes a pallet that circulates and moves, a raw material supply device that charges a sintered raw material on the pallet to form a charging layer, and a charcoal on the surface layer of the charging layer. An ignition furnace for igniting the material, a wind box disposed below the pallet, and disposed downstream of the ignition furnace, injecting gaseous fuel above the charging layer and mixing with air, The gaseous fuel supply device that is diluted below the lower combustion limit concentration and supplied into the charging layer, the hood that surrounds the gaseous fuel supply device, and the temperature distribution in the pallet width direction of the raw material charging layer surface layer on the ignition furnace outlet side An ignition failure region detection device that measures and identifies an ignition failure region in the pallet width direction, and a gaseous fuel that increases a gaseous fuel supply amount in the ignition failure region in the pallet width direction based on the detection result of the ignition failure portion detection device Equipped with a supply control device A sintering machine of the Te.

  The ignition failure region detection device in the sintering machine of the present invention includes a thermo camera that measures the temperature distribution in the pallet width direction in the raw material charging layer surface layer on the ignition furnace exit side, and a raw material from the temperature distribution measured by the thermo camera. It has an image processing device for specifying a poor ignition region in the pallet width direction of the charging layer surface layer.

  Further, the gaseous fuel supply amount control device in the sintering machine of the present invention feeds the ignition failure region information from the ignition failure region detection device to the gas fuel control unit, and supplies the gaseous fuel supply amount to the ignition failure region. Is increased from other regions.

  Further, the gaseous fuel supply device in the sintering machine of the present invention has a plurality of gaseous fuel supply pipes arranged in parallel to the moving direction of the pallet and in the width direction, and the pallet according to an instruction from the gaseous fuel supply amount control device. It has a function of individually controlling the supply amount of gaseous fuel injected from a plurality of gaseous fuel supply pipes arranged in the width direction.

  The gaseous fuel in the sintering machine of the present invention is selected from blast furnace gas, coke oven gas, blast furnace / coke oven mixed gas, city gas, natural gas, methane gas, ethane gas, propane gas, and mixed gas thereof. Any flammable gas.

  Further, the present invention is a gas fuel supply method in any one of the above-mentioned sintering machines, and based on the temperature distribution in the pallet width direction of the raw material charging layer disposed on the ignition furnace outlet side, the pallet width direction In the sintering gas fuel supply method, the ignition failure region is identified and the gas fuel supply amount to the gas fuel supply pipe in the ignition failure region is increased from that in the other regions.

  According to the present invention, in the gas fuel supply sintering operation in the downward suction type sintering machine, the gaseous fuel in the pallet width direction is based on the ignition state of the surface layer of the sintering raw material charged layer observed on the exit side of the ignition furnace. By controlling the supply amount, it is possible to suppress a decrease in the strength of the sintered ore due to the lack of heat in the poor ignition region, and thus it is possible to manufacture a high-quality sintered ore with high productivity.

It is the schematic of the conventional sintering machine. It is a figure which illustrates typically the change in the charging layer accompanying progress of sintering. It is a figure explaining the pressure loss and temperature distribution in a sintered layer. It is explanatory drawing which compared the temperature distribution at the time of high production and low production, and high temperature range holding time. It is a graph which shows the change of the temperature history in the thickness direction in a charging layer, and the yield distribution in the charging layer width direction cross section. It is the schematic which shows one form of the sintering machine used for implementation of this invention. It is a perspective view which shows schematic structure of a gaseous fuel supply apparatus. It is a typical cross section of the pallet width direction of a gaseous fuel supply apparatus. It is a figure explaining the gaseous fuel injection state of a gaseous fuel supply apparatus. It is a figure explaining the gaseous fuel supply system of the sintering machine of this invention. It is a schematic diagram explaining the ignition failure area | region in an ignition furnace exit side. It is a graph which shows the influence of the dilution density | concentration which acts on the combustion poison degree of gaseous fuel. It is a flowchart of the gaseous fuel supply amount control procedure in this invention.

Hereinafter, embodiments of the present invention will be specifically described.
FIG. 6 is a schematic configuration diagram of a sintering machine to which the present invention can be applied. As described above, iron ore powder, iron mill recovered powder, sintered ore sieving powder, limestone, and dolomite-containing CaO System auxiliary materials, granulation aids such as quick lime, raw materials such as coke powder and anthracite are cut out from individual hoppers 1, mixed with an appropriate amount of water by drum mixers 2a and 2b, granulated, and an average diameter of 3 A sintered raw material which is a pseudo particle of 0.0 to 6.0 mm is stored in the surge hopper 5 of the sintering machine 3 and a fine-grained sintered ore (returned ore) is stored in the floor hopper 4. .

  The sintering machine 3 has an endless moving pallet 8 disposed below the floor hopper 4 and the surge hopper 5, and the fine sinter (from the floor hopper 4 to the fine sinter ore as the pallet 8 moves. (Returning) is cut out to form a floor layer on the pallet 8 great, and a sintered raw material is charged from the surge hopper 5 through the drum feeder 6 and the cutting chute 7 onto the floor layer. Unevenness on the upper surface of the layer is smoothed by the cut-off plate 12 to form a raw material charging layer 9 having a thickness (height) of about 400 to 800 mm, which is also called a sintered bed. Here, the floor hopper 4, the surge hopper 5, the drum feeder 6 and the cut chute 7 constitute a mining section.

  An ignition furnace 10 is disposed on the downstream side of the cut-off plate 12 and above the raw material charging layer 9. The ignition furnace 10 ignites the carbon material in the surface layer of the raw material charging layer 9. C gas (coke oven gas) is generally used as the fuel gas for the ignition furnace 10.

  Further, on the downstream side of the ignition furnace 10, a gaseous fuel supply device 13 is arranged in series in the moving direction of the pallet 8, and the raw material charge is placed at a position after ignition of the carbon material in the surface layer of the raw material charge layer 9. The diluted gas fuel is supplied into the entrance layer 9. That is, one or more (three in FIG. 6) gas fuel supply devices 13 are disposed at any position after the downstream side of the ignition furnace 10 and the combustion / melting zone has progressed below the surface of the charging layer 9. Is done. The size, position, and number of installations of the gaseous fuel supply device are determined from the viewpoint of optimizing the cold strength and reducibility of the target product sintered ore.

  Below the pallet 8 on which the charging layer 9 is formed, a combustion / melting zone formed by igniting the carbonaceous material in the charging layer 9 is sequentially introduced as the pallet 8 moves. In order to move to the lower layer side of 9, a wind box 11 for sucking air from the upper layer of the charging layer 9 toward the lower layer is provided.

  As shown schematically in FIGS. 7 and 8, the gaseous fuel supply device 13 is surrounded by a hood 14 having an open upper end. The hood 14 includes a hood base 14a formed on the front and rear of the pallet 8 in the moving direction and on both sides of the width end, and a punch having a transmittance of, for example, 45%, which is disposed by extending the upper end of the hood base 14a. The anti-scattering fence 14b is made of metal or the like.

  Further, as schematically shown in FIG. 8, a baffle plate 15 a that extends in the direction of conveyance of the pallet 8 and has a cross-sectional shape with the top at the top is provided in the hood 14 in the width direction of the pallet 8. A baffle plate group in which a plurality of baffle plate rows 15b arranged in parallel with a predetermined pitch are arranged in a staggered (tournament) or labyrinth manner (three stages in FIG. 8) by shifting the position in the vertical direction. 15 is installed.

  The baffle plate group 15 suppresses the formation of eddy currents when passing between the baffle plates 15a and rectifies the air so that it is uniform with the gaseous fuel supplied from the gaseous fuel supply pipe 31 described later. In addition, the diluted gaseous fuel can be prevented from leaking outside.

  In the hood base 14a, a plurality of gaseous fuel supply pipes 31 are arranged along the movement direction of the pallet 8 and in parallel with a predetermined pitch in the pallet width direction, for example, in FIGS. Seven are arranged. As shown in FIG. 9, each of these gaseous fuel supply pipes 31 is provided with gas fuel injection ports 31a such as openings or injection nozzles at a predetermined pitch, and gaseous fuel 32 is supplied from these injection ports 31a. Is injected into the atmosphere at high speed and instantly diluted below the lower combustion limit concentration.

  The gas fuel injection ports 31a of the openings or the injection nozzles are oriented in the horizontal direction and shifted from the injection ports of the adjacent gas fuel supply pipes as shown in FIG. Due to the arrangement, the injected gaseous fuel 32 is uniformly mixed without interfering with each other. The gaseous fuel 32 to be injected is made uniform as described above, and then sucked by the wind box 11 under the pallet 8 and introduced into the charging layer 9.

  The gaseous fuel 32 includes blast furnace gas (B gas), coke oven gas (C gas), blast furnace / coke oven mixed gas (M gas), natural gas (LNG), city gas, methane gas, ethane gas, and propane gas. And any combustible gas chosen from those gas mixtures can be used.

  Further, the gaseous fuel supply system to each gaseous fuel supply device will be described in the example shown in FIG. 10 in which three gaseous fuel supply devices 13 having seven gaseous fuel supply pipes are installed. The gaseous fuel 32 supplied to the gaseous fuel supply device 13 is first branched into gaseous fuel supply branch pipes 42 a to 42 c that are connected from the gaseous fuel supply main pipe 41 to the gaseous fuel supply devices 13 and in which a shutoff valve 44 is inserted. And supplied to the individual gaseous fuel control units 43a to 43c. Next, the gaseous fuel control unit 43a will be described as an example. The gaseous fuel supplied to the gaseous fuel supply branch pipe 42a is divided into seven systems of branch pipes 46 by a branching part 45 installed on the downstream side of the shutoff valve 44. Then, it is supplied to a gaseous fuel supply pipe 31 having an injection port 31a for injecting gaseous fuel into the atmosphere. Note that a flow meter 47 and a flow rate adjusting valve 48 are inserted in the respective branch pipes 46 in that order, and the flow rate of the gaseous fuel flowing through each branch pipe 46 is controlled by a gaseous fuel supply amount control device 24 described later. Can be adjusted by an instruction from the control, that is, the supply amount of gaseous fuel in the pallet width direction can be adjusted.

  The gaseous fuel 32 supplied from the gaseous fuel supply pipe 31 is made uniform in the pallet width direction and introduced into the charging layer 9. However, as shown in FIG. 11, when a poor ignition region has occurred on the surface of the sintered raw material charging layer that has come out of the ignition furnace, a gaseous fuel supply effect is obtained in the poor ignition region. Disappear. This is because the lower the concentration, the lower the combustion speed, and the poorly ignited part where the temperature rise is insufficient will not burn in the part where the supplied gaseous fuel is expected, and the gaseous fuel combustion effect will be sufficiently obtained. Absent. Therefore, not only can the area not secure the maximum temperature and holding time required for sintering, but also the strength of the sintered ore is reduced due to insufficient heat, and the yield and productivity are reduced. Because.

For example, the combustion rate of gaseous fuel diluted by mixing with the atmosphere will be described using LNG mainly composed of methane as an example. The combustion reaction formula of methane (CH ₄ ) is
CH ₄ + 2O ₂ → CO ₂ + 2H ₂ O
And the reaction rate r is
r = k * [CH ₄ ] * [O ₂ ]
([CH ₄ ]: methane concentration (vol%), [O ₂ ]: oxygen concentration (vol%), k: reaction rate constant)
It is represented by The reaction rate constant k is an Arrhenius equation;
k = A * exp (-E / RT)
(A: constant, E: activation energy, R: gas constant, T: temperature (K))
It is supposed to follow.
From the above equation, FIG. 12 shows the change in the combustion rate due to the diluted concentration of methane, and it can be seen that the combustion rate also decreases as the concentration decreases.

  Therefore, in the present invention, in order to eliminate the shortage of heat in the ignition failure region on the surface of the raw material charging layer, the raw material charging at the ignition furnace outlet side as shown in FIG. The temperature distribution in the pallet width direction of the surface layer is measured, and the ignition failure region detection device 21 that identifies the ignition failure region and the gaseous fuel supply amount is adjusted (increased) based on the detection result of the ignition failure region detection device. By providing the gaseous fuel supply amount control unit 24, the gaseous fuel supply amount in the ignition failure region in the pallet width direction is increased, that is, the concentration of the gaseous fuel introduced into the ignition failure portion is increased.

  By increasing the concentration of the gaseous fuel, temperature unevenness due to poor ignition can be eliminated at an early stage, and a shortage of heat can be avoided. That is, since the region where the ignition failure has occurred is lower than the temperature necessary for the combustion of the diluted gaseous fuel, the combustion speed becomes slow at the same gaseous fuel concentration as the other regions, and the gaseous fuel is in the raw material charging layer. It passes without burning. However, if gaseous fuel with a higher concentration is supplied to the ignition failure area than other areas, the gaseous fuel supplied to the area will burn at a high speed even at low temperatures, and the supply amount of the gaseous fuel will increase. Therefore, the amount of heat generation increases, and problems due to poor ignition are eliminated or reduced.

  However, in the case where the width of the ignition failure region of the raw material charging layer surface layer when it leaves the ignition furnace exceeds 150 mm, the gaseous fuel burns even if the amount of gaseous fuel supplied to this region is increased. Without passing through the sintered raw material charging layer and flowing into the wind box, problems due to poor ignition are not solved or alleviated, and there is a risk of explosion and fire. Therefore, when the width of the unignited region at the time of exiting the ignition furnace exceeds 150 mm, it is preferable to urgently stop the sintering machine and repair the ignition furnace (ignition burner).

  Here, as shown in FIG. 13, the ignition failure region detection device 21 is installed facing the surface of the raw material charging layer immediately after coming out of the ignition furnace, and takes a thermal distribution image of the charging layer surface. 22 and the heat distribution image obtained by the thermo camera 22 are subjected to image processing to measure the temperature distribution in the pallet width direction, the ignition failure region is specified, and the result is output to the gaseous fuel supply amount control device 24 It is preferable to have a processing device 23. The thermocamera 22 that captures the heat distribution image may be any one as long as a heat distribution image of the raw material charge layer surface can be obtained. For example, an infrared camera or a thermography camera (thermoviewer) may be used. it can.

  Further, the ignition failure region in the image processing device 23 is specified by obtaining a temperature distribution in the pallet width direction from a heat distribution image obtained by the thermo camera 22 such as the infrared camera or the thermography camera (thermo viewer). When the temperature is equal to or higher than a predetermined temperature over almost the entire area in the pallet width direction, it is determined that the sintering has been normally performed. If it exists, the low temperature portion is determined as a poor ignition region. Note that the above-mentioned ignition failure area is specified by measuring the brightness of the obtained heat distribution image or the width of the red tropics above a predetermined brightness instead of the temperature distribution of the sintered cake, and increasing the brightness and width. It may be done on the basis. This is because the luminance of the image is based on temperature and is equivalent.

  In the present invention, the information on the ignition failure region specified by the ignition failure region detection device 21 is transmitted to the gaseous fuel supply amount control device 24, and the ignition is performed based on an instruction from the gaseous fuel supply amount control device 24. Feed forward is performed to the gaseous fuel control units 43a to 43c so that the gaseous fuel supply amount in the defective area is increased from the other areas. Specifically, the gaseous fuel supply amount control device 24 adjusts the opening degree of the flow rate control valve 48 disposed in the branch pipe 46 of each of the gaseous fuel control units 43a to 43c based on the ignition failure region data. Then, the amount of gaseous fuel supplied to the poor ignition region is increased. As a result, the amount of heat generated in the insufficient heat amount region due to the ignition failure increases, and the problem of insufficient sintering is solved.

  It should be noted that the amount by which the gaseous fuel supply amount is increased is preferably changed within a range of 50 to 200% with respect to the reference supply amount, depending on the difference in temperature and brightness between the poor ignition region and other regions. If the increase amount is less than 50% with respect to the reference supply amount, the effect of increasing the gaseous fuel is not sufficient, and there is a possibility that the shortage of heat cannot be solved. This is because fears arise. However, the gaseous fuel may be simply increased in a range of 50 to 200% with respect to the reference supply amount with respect to the region specified as the ignition failure region.

  As for the method of increasing the gaseous fuel supply amount to the poor ignition region, only the gaseous fuel supply amount from the gaseous fuel supply pipe disposed immediately above the poor ignition region is increased, and the gaseous fuel supply from other regions is performed. A method of keeping the gaseous fuel supply amount from the pipe constant may be used, or the gaseous fuel supply amount is made constant throughout the apparatus, and the gaseous fuel supply amount from the gaseous fuel supply pipe disposed immediately above the ignition failure region is increased. Alternatively, a method of reducing the amount of gaseous fuel supplied from the gaseous fuel supply piping in another region may be used.

  When the supply amount (concentration) of gaseous fuel is changed in a partial region in the pallet width direction as in the present invention, a partition plate or the like is provided between the gaseous fuel supply pipes arranged in parallel in the pallet width direction. It is also preferable to suppress the diffusion of the gaseous fuel to other regions by installing or lowering the installation height of the gaseous fuel supply pipe and bringing it close to the surface of the raw material charging layer.

Three gas fuel supply devices having a length of 5 m, an effective machine length of 82 m, and six gas fuel supply pipes arranged at intervals of 800 mm in the pallet width direction and having a length of 7.5 m are provided. As shown in FIG. 13, a 22 m ³ (ntp) / hr gaseous fuel per cylinder was supplied into the raw material charging layer to perform a sintering operation. A thermo camera that captures the heat distribution image of the surface of the charged material layer facing the surface of the charged material layer, and the temperature distribution of the surface of the raw material charged layer by image processing the heat distribution image obtained by the thermo camera. Based on the image processing device that measures and identifies the ignition failure region, and the ignition failure region information specified by the image processing device, the gaseous fuel is made into the ignition failure region in the gaseous fuel supply device installed downstream of the ignition furnace. Flow installed in the branch pipe to be supplied A gas fuel supply amount control device for instructing to adjust the opening degree of the control valve is installed, and the firing of the example of the present invention to which the gas fuel supply method of the present invention for increasing the gas fuel supply amount to the poor ignition region is applied. An experiment was conducted to compare the rate of occurrence of return ore for the sintering operation and the sintering operation of the comparative example not applied. In this sintering experiment, the amount of carbonaceous material added to the sintering raw material was 4.0 mass%, and the dilution concentration of LNG was 0.4 vol%. Further, in the gaseous fuel supply method of the present invention, specifically, the supply amount from the gaseous fuel supply pipe disposed just above the ignition failure area is increased in a range of 0 to 200% depending on the degree of ignition failure. Then, the supply amount from the gaseous fuel supply pipe on the other region was decreased, and the gaseous fuel supply amount in the entire three gaseous fuel supply devices was controlled to be constant at 390 m ³ (ntp) / hr.

  Table 1 shows a comparison of the return rate of sintered ore when the gaseous fuel supply method according to the present invention is not applied and when it is applied. It can be seen that the incidence is reduced by about 1.6%. This is because the application of the present invention eliminates the shortage of heat in the poorly ignited region, and as a result of uniform and sufficient sintering, the strength of the sintered ore is increased and the fine-grained sintered ore after crushing is increased. Indicates a decrease in product yield.

  The technology of the present invention is effective not only for solving a shortage of heat in a portion with poor ignition, but also for eliminating burning unevenness caused by non-uniform gas flow.

1: Hopper 2a, 2b: Drum mixer 2a, 2b
3: Sintering machine 4: Floor hopper 5: Sintering raw material surge hopper 6: Drum feeder 7: Cutting chute 8: Pallet 9: Raw material charging layer (sintering bed) 10: Ignition furnace 11: Wind box 12: Cut-off Plate 13: Gaseous fuel supply device 21: Ignition failure area detection device 22: Thermo camera 23: Image processing device 24: Gaseous fuel supply amount control device 31: Gaseous fuel supply piping 31a: Gaseous fuel injection port 32: Gaseous fuel 41: Gaseous fuel supply main pipes 42a to 42c: Gaseous fuel supply branch pipes 43a to 43c: Gaseous fuel control section 44: Shut-off valve 45: Branch section 46: Branch pipe 47: Flow meter 48: Flow control valve

Claims (6)

A circulating pallet,
A raw material supply device for charging a sintered raw material on the pallet to form a charging layer;
An ignition furnace for igniting the surface carbon material of the charging layer;
A wind box disposed below the pallet;
A gaseous fuel supply device disposed downstream of the ignition furnace, injecting gaseous fuel above the charging layer, mixing with air, diluting below the lower combustion limit concentration and supplying it into the charging layer;
A hood surrounding the gaseous fuel supply device;
Measure the temperature distribution in the pallet width direction of the raw material charging layer surface layer on the ignition furnace exit side, and specify an ignition failure area detection device that identifies an ignition failure area in the pallet width direction;
The sintering machine provided with the gaseous fuel supply amount control apparatus which increases the gaseous fuel supply amount in the ignition failure area | region of a pallet width direction based on the detection result of the said ignition failure part detection apparatus. The ignition failure region detection device is a thermo camera that measures the temperature distribution in the pallet width direction in the raw material charging layer surface layer portion on the ignition furnace exit side,
2. The sintering machine according to claim 1, further comprising an image processing device that identifies an ignition failure region in a pallet width direction of a raw material charging layer surface layer portion from a temperature distribution measured by the thermo camera. The gaseous fuel supply amount control device feeds forward the ignition failure region information from the ignition failure region detection device to a gas fuel control unit, and increases the gas fuel supply amount to the ignition failure region from other regions. The sintering machine according to claim 1 or 2. The gas fuel supply device has a plurality of gas fuel supply pipes arranged in parallel in the width direction and in the width direction of the pallet, and a plurality of gas fuel supplies arranged in the pallet width direction according to an instruction from the gas fuel supply amount control device The sintering machine according to any one of claims 1 to 3, wherein the sintering machine has a function of individually controlling a supply amount of gaseous fuel injected from a pipe. The gaseous fuel is any flammable gas selected from blast furnace gas, coke oven gas, blast furnace / coke oven mixed gas, city gas, natural gas, methane gas, ethane gas, propane gas and mixed gas thereof. The sintering machine according to any one of claims 1 to 4, wherein: It is a gaseous fuel supply method in the sintering machine of any one of Claims 1-5,
Based on the temperature distribution in the pallet width direction of the surface layer of the raw material charging layer disposed on the exit side of the ignition furnace, the ignition failure region in the pallet width direction is specified, and the gaseous fuel supply to the gas fuel supply pipe in the ignition failure region A method for supplying gaseous fuel to a sintering machine, characterized in that the amount is increased from other regions.