JPS6311412B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention relates to a method of operating a sintering machine,
In particular, operations during significantly reduced production in sintering equipment that is equipped with a cooler attached to the outlet side of the sintering machine and is configured to recover waste heat during ventilation cooling of the sintered ore in the cooler. It is about the method. (Description of Prior Art) Generally, a sintering machine is equipped with a cooler attached to the outlet side of the sintering machine, and this cooler is designed to recover the sensible heat of the red-hot sintered ore discharged from the sintering machine. An exhaust heat recovery facility is provided, and such a sintering device as shown in FIG. 1 is conventionally used. In Fig. 1, 1 is a pallet, 2 is a wind box, 3 is an igniter, 4 is a bedding hopper,
5 is a raw material hopper, 6 is a cooler, and 7 is a heat recovery heat exchanger such as a boiler. A plurality of pallets 1 are successively connected to form an endless belt, which is driven via sprocket wheels 8 and 9 at both ends. To such a pallet, bedding ore is laid from the bedding hopper 4 at the entrance end of the sintering machine, and then the sintering raw material is continuously charged from the raw material hopper 5 and transferred in a constant layer thickness. is configured to do so. Further, the ignition device 3 includes a burner located directly above the pallet, from which fuel gas such as heavy oil, coke oven gas, or a mixed gas of coke oven gas and blast furnace gas, and combustion air are sent to the incinerator deposited on the pallet. It is injected onto the upper surface of the crystalline material layer to cause it to burn and ignite the surface of the material. Furthermore, a ventilation device 10 is provided to promote combustion, and is configured to draw air from the upper part of the material charging layer to the lower part of the pallet through a wind box 2 after ignition. At the exit end of the sintering machine, the sintered ore in the pallet 1 is normally in a red-hot state of about 550°C, and therefore the sintered ore is discharged to the sintered ore cooler 6 installed at the later stage. It is sent out through a device 11 and cooled. In the cooler 6, the exhaust from the highest temperature section 6a at the inlet end passes through the dust remover 12 and the blower 13 to the boiler 7 together with the exhaust from the other high temperature sections 6b and 6c, where the sensible heat is removed by heat exchange. The exhaust gas, which has been converted into steam and whose temperature has been lowered thereby, is circulated and supplied as suction air to the cooler 6 by the circulation blower 14. 15 is a screening screen, and 16 is a suction cooling fan. Incidentally, in such a sintering apparatus, the sintering production volume (T/D) may be changed due to changes in economic conditions or the like. For example, when a low production volume operation is required, the countermeasure is usually to reduce the thickness of the material layer on the pallet or to reduce the pallet speed. Among the conventional measures, reducing the thickness of the raw material layer has the major disadvantage of worsening the cold strength (SI) of the finished sintered ore and increasing the coke consumption rate.
This method is rarely adopted. Therefore, for low production volumes, the latter method of slowing down the pallet speed is usually adopted. this is,
The production amount is proportional to the amount of sintered ore on the sintering machine, and the amount of sintered ore (T/H) is determined by the layer thickness (m), layer width (m), and bed packing density (T/m ³ ). This is because the pallet speed has to be fixed at a low speed because it is expressed as the product of the pallet speed (m/H) and the pallet speed (m/H). However, according to this conventional method, the sintering time (= sintering machine effective length/pallet speed) is longer than in high-production operation, so the so-called cooling near the ore discharge part of the sintering machine is As the time becomes longer, the problem arises that the reduced decay index (RDI) of the finished sintered ore deteriorates. As is well known, this
This is because when the cooling time on the sintering machine becomes longer, the amount of secondary hematite precipitated due to reoxidation increases proportionally in the internal structure of the sintered ore, which worsens the RDI of the sintered ore. In this way, with conventional sintering equipment, when operating to change the production volume, such as lowering the production volume, the pallet speed has to be changed, which ultimately leads to a worsening of the RDI of the sintered ore. Eventually high RDI in blast furnace
A problem has arisen in that the supply of sintered ore often disturbs the furnace conditions. Furthermore, in the case of low production volumes, the temperature of the red-hot sintered ore discharged from the sintering machine decreases due to lower coke consumption and longer cooling times. There is a problem in that the heat recovery efficiency in the cooler in the subsequent process is reduced. In view of the above-mentioned problems that arise when operating at a low production volume, the applicant previously proposed that the ignition device be installed in the longitudinal direction of the sintering machine in accordance with Utility Application No. 129523/1983 (Utility Model Application No. 34299/1983). By making the distance from the ignition position to the ore discharge position variable, the sintering equipment can be operated without reducing RDI even in so-called low-production operations where production volume is reduced. Proposed. In recent years, waste heat recovery equipment has been installed in sinter coolers, making it possible to smoothly operate low production volumes without causing quality deterioration like RDI or reducing waste heat recovery efficiency. Technology that can do this is required. However, as mentioned above,
As in the sintering device according to No. 129523, with the conventional ignition system in which multiple single burners are arranged in a row, uniform ignition in the width direction of the pallet cannot be expected, and therefore it is extremely difficult to improve waste heat recovery efficiency. It was hot. (Object of the Invention) In view of the above-mentioned conventional problems caused by production volume change operations, the object of the present invention is to generate a short, band-shaped flame uniformly in the width direction of the pallet using an ignition device, and to By adjusting the position of the igniter along the length of the sintering machine based on the sintering state measured between the coolant and the coolant, the effective length of the sintering machine can be adjusted appropriately according to the production volume. , a sintering machine that can produce the best sintered ore even during production volume change operations and prevent a decrease in heat recovery efficiency in the cooler by keeping the sintering time constant, especially the cooling time. The aim is to provide a method for operating the system. (Structure of the Invention) In order to achieve the above-mentioned object, the present invention charges raw materials into pallets connected in an endless belt shape, transfers the raw materials in the length direction of the sintering machine, and transfers the raw materials by an ignition device. The raw material is sintered by igniting and drawing air downward into the raw material layer during transport, and at the outlet end of the sintering machine, the sintered ore is discharged into a cooler, and the sintered ore layer is cooled by ventilation in the cooler. In a sintering operation method that recovers waste heat from the generated high-temperature hot air,
The igniter has a burner tip extending substantially across the entire width of the pallet, and the burner tip alternately transfers gas from a plurality of pairs of fuel gas nozzle holes and air nozzle holes, each pair being spaced apart along the length of the burner tip. The sintered ore is injected in the direction that intersects the sintered ore to generate a short flame band that is uniform in the width direction of the pallet, and the sintered state of the sintered ore discharged into the cooler is measured. It is characterized by adjusting the position by moving along the length direction of the knot. (Description of Preferred Embodiments of the Invention) Figures 2 to 6 show preferred specific examples of a mobile ignition device used to carry out the present invention, and the illustrated ignition device includes a burner main body B _b and a The main body is equipped with a removable burner chip _Bt . Burner body as shown in Figures 2 and 3
B _b includes a fuel gas pipe 17 and a combustion air pipe 1.
8 are provided to extend substantially parallel to each other in the width direction of the pallet, and a fuel gas supply pipe 19 and an air supply pipe 20 are similarly provided to extend in the width direction across the entire width of the pallet. A gas pipe 17 and a gas supply pipe 19 are connected via short pipes 21 and 22 at a plurality of locations in the axial direction, and an air pipe 18 and an air supply pipe 20 are connected to each other through short pipes 21 and 22.
are communicated individually. Fuel gas pipe 17
The combustion air pipe 18 and the combustion air pipe 18 are constructed of concentric double pipes, and the fuel gas pipe 1 constituting the central passage 17a
Coke oven gas or the like is made to flow through the inside of the pipe 7, while air is made to flow through the air pipe 18 constituting the annular passage 18a. In the central passage 17a of the fuel gas pipe and the annular passage 18a of the air pipe, rectifying plates 24 and 25 each having a large number of through holes 23 are installed so that they can be inserted and removed. It plays the role of distributing the flow. A slit-shaped fuel gas burner passage 26 and an air burner passage 2 extend from the fuel gas pipe 17 and the combustion air pipe 18 in the width direction of the pallet.
Protrusions 17' and 18' forming numerals 7 and 27' respectively protrude in the radial direction, and a flange 28 is provided at the tip of the protrusion 18'. The burner tip B _t has the above burner body B _b
A gas nozzle passage 29 and an air nozzle passage 30, 30' are provided corresponding to the fuel gas burner passage 26 and the air burner passage 27, 27', respectively, and a large number of nozzle holes 31, 31', 32, and 32' are opened as shown in FIG. 4, and a flange 33 corresponding to the flange 28 of the burner body _B
A flange 33 is protruded from the upper end of B _t and is detachably attached to the flange 28 via bolts 34 . The fuel gas nozzle holes 31, 31' in the burner chip _Bt are open in directions facing both outsides, and the air nozzle holes 32,
32', on the other hand, is opened inward, and the two injection directions are formed to intersect with each other. Moreover, each such nozzle hole 31, 31',
As shown in FIG. 4, a large number of combinations of tubes 32 and 32' are arranged in the tube axis direction across the width of the pallet at intervals of, for example, about 10 to 20 mm. Arrangement and combination of the above-mentioned nozzle holes 31, 31' 32, 32' (so that the injection directions intersect)
Compared to conventional burners in which multiple single burners are arranged in rows, the flame becomes shorter because the fuel gas and air are injected through small-diameter holes, preferably intersecting at right angles. For this reason, the upper surface of the sintered raw material layer on the pallet and the burner tip _Bt can be brought close to each other. As a result of this,
The burner hood can have the following structure. That is, since the burner hood 35 can be made smaller not only in the height direction but also in its entirety, energy loss is reduced based on equipment downsizing, and construction costs are reduced. Furthermore, the effect of making the burner hood 35 smaller produces the following synergistic effect in conjunction with the use of the removable burner tip _Bt . That is, if the burner tip _Bt of the present invention is adopted, ignition can be performed uniformly in the width direction of the pallet and is _advantageous in terms of thermoeconomics.
It will be enough to cover only that part. However, this problem, which is a phenomenon often observed in conventional burners, causes the disadvantage that the burner chip _Bt is easily overheated and thermal deformation occurs. In order to avoid this, it is desirable to be able to easily replace only the burner tip _Bt , and in order to meet this need, the present invention has made the tip removable from the burner body. Furthermore, in order to facilitate replacement, a burner hood is provided below the removable part of the burner chip to protect the removable part from high heat and prevent thermal deformation of the removable part. An ignition device including a burner as described above is mounted so as to be movable in the longitudinal direction of the sintering machine. For this reason, as shown in FIGS. 5 and 6, rails 37 are provided on both sides along the length of the sintering machine on a pedestal 36 on which pallet running rails are laid.
An ignition device supporting traveling frame 38 is provided so as to be freely movable on the rails 37 by means of wheels 39, and a traveling motor 40 is installed.
and an upright frame 4 which is movable in the length direction of the sintering machine by a belt 41 and fixed on a traveling frame 38.
2, an elevating saddle 43 is attached so that it can be raised and lowered by a cylinder device 44 or other suitable elevating device, and the burner main body B _b is fixed to a girder pipe 45 rotatably supported between the elevating saddles 43 on both sides. A tilting device is provided in which a large gear 46 fixed to one end of the tube is rotated by a motor 48 via a small gear 47 that meshes with the large gear 46, and can be fixed at the rotating position with a pin 49 or the like. A flexible hose is used as a supply pipe for supplying fuel gas and combustion air to the fuel gas pipe 17 and the combustion air pipe 18 of the burner body B _b , respectively. A fuel gas supply pipe 19 is connected by a flexible hose 53 to a fuel gas main pipe 50 fixedly installed in advance on the fuel gas main pipe 50 via a gate valve 51 and an outlet 52, so that it can be extended in response to movement of the ignition device. It is composed of If the moving position of the igniter is determined to a certain extent, the fuel gas and combustion air outlets 52 can be provided at multiple locations along the length of the sintering machine, as shown in FIG. Once the setting position of _b in the longitudinal direction of the sintering machine is determined,
Gas and air can also be supplied by connecting flexible gas and air hoses 53 to desired outlets 52. Next, a method of carrying out the invention using a sintering machine equipped with a mobile ignition device as described above will be explained with reference to FIG. In the case of low production operation, the sinter ore removal equipment 11
An infrared television (ITV) camera 54 installed in the sintered layer detects the red-hot area of the cross section of the sintered layer to measure the sintering state, and based on this measurement, the ignition device 3 is moved from the position indicated by A in FIG. The sintered state can be measured by moving to the B or C position and adjusting the position. The temperature can be measured by providing a temperature detector such as an infrared thermometer, or the inlet temperature of the boiler 7 or the temperature of high-temperature exhaust discharged from the sintered ore cooler 6 can be detected and measured. Table 1 shows an example of operation when a sintering machine with a capacity of 7000T/D is reduced in production to 6000T/D and 5000T/D. According to the sintering state measured by ITV camera 54, when the production amount is 6000T/D, B
When the temperature is 5000T/D, the ignition device 3 is moved to point C, and the surface of the sintering raw material is ignited and sintered.

[Table] As is clear from the results shown in Table 1, not only the quality represented by RDI, but also the heat recovery amount represented by the boiler inlet exhaust gas temperature and boiler steam generation amount compared to normal operation. Almost similar results were obtained by moving the ignition device to points , B, and C. Furthermore, by moving the igniter to point B or point C for low production operation, a portion of the windbox located below the pallet will be closed, and therefore the exhaust fan 10 will The amount of suction air is reduced, and the power consumption of the exhaust fan 10 can be reduced. In addition, by using the ignition device having the multi-hole burner shown in the above-mentioned embodiment, the burner flame becomes a short flame band that is uniform in the width direction of the pallet, so the ignition strength becomes uniform and the hood can be made smaller. Energy loss can be significantly improved. For example, according to experiments conducted by the present inventors, a conventional ignition system equipped with a single burner had a fuel consumption of 15,000 Kcal/t-Sinter;
9000Kcal/t-Sinter (sinter production 7000T/D,
3.9Nm ³ /t, A/G=2.2, mixed calories=
2300Kcal/Nm ³ ). In addition, since the burner chip _Bt of the igniter is removable from the burner body _Bb ,
The burner tip can be easily replaced, and the burner tip can also be made of heat-resistant steel, which extends the life of the igniter and reduces the overall size of the device. Maintenance costs can be reduced. (Explanation of the effects of the invention) According to the conventional technology, when operating at a significantly low production volume, it was impossible to avoid a decline in quality as represented by RDI and a decline in waste heat recovery efficiency. According to the above, by making the burner flame of the ignition device into a short band-shaped flame that is uniform in the width direction of the pallet, the ignition strength can be made uniform, uneven burning can be eliminated, and the exhaust heat recovery efficiency can be increased. By adjusting the effective length of the sintering machine by moving it along the length of the sintering machine according to the sintering condition, low production volume operations can be smoothly performed with almost the same quality and waste heat recovery efficiency as normal operations. can be done.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a sintering machine and a sintered ore cooler implementing the present invention, Fig. 2 is a longitudinal sectional view of the burner portion of the ignition device, and Fig. 3 is a partially cutaway diagram of the ignition device. A bottom view of the burner section, Figure 4 is an enlarged bottom view of the nozzle hole of the burner chip, and Figure 5 is a front view of the ignition device that is movable in the length direction of the sintering machine and is placed directly above the pallet of the sintering machine. , FIG. 6 is a side view of the ignition device shown in FIG. 5. B _b ...burner body, B _t ...burner tip, 1
... Pallet, 2... Wind box, 3... Ignition device, 4, 5... Hopper, 6... Cooler, 7... Boiler, 8, 9... Sprocket wheel, 10... Air exhaust device, 11... Sintered ore discharge device , 12...dust remover, 1
3...Blower, 14...Circulation blower, 15...Sieving screen, 16...Suction cooling fan, 17...
Combustion gas pipe, 18... Air pipe for combustion, 19... Fuel gas supply pipe, 20... Air supply pipe, 21, 22... Short pipe, 23... Through hole, 24, 25... Straightening plate, 26... Burner passage for fuel gas , 27, 27'... Air burner passage, 28... Flange, 29... Gas nozzle passage, 30, 30'... Air nozzle passage, 31, 3
1', 32, 32'...nozzle hole, 33...flange,
34... Bolt, 35... Burner hood, 36... Frame, 37... Rail, 38... Ignition device support traveling frame, 39... Wheel, 40... Traveling motor, 41... Belt, 43... Lifting saddle, 44... Cylinder device,
45... Girder pipe, 46... Large gear, 47... Small gear, 48... Motor, 49... Latching pin, 50... Fuel gas main pipe, 51... Gate valve, 52... Outlet, 53...
Flexible hose, 54...Infrared television camera.

Claims (1)

[Claims] 1 The sintering raw material is charged into pallets connected in an endless belt shape, and the sintering raw material is transferred in the length direction of the sintering machine.The sintering raw material is ignited by a movable ignition device, and the raw material is ignited during the transfer. The sintered raw material is sintered by drawing air downward through the layer, and at the outlet end of the sintering machine, the sintered ore is discharged into a cooler. In a method of operating a sintering machine in which waste heat is recovered from a pallet, the igniter has a burner tip extending substantially across the width of the pallet, and a plurality of burner tips each provided at a lengthwise distance from the burner tip. Gas is injected from a pair of fuel gas nozzle holes and an air nozzle hole in mutually intersecting directions to generate a uniform band-shaped short flame in the width direction of the pallet, and the sintered state of the sintered ore discharged into the cooler is measured. A method for operating a sintering machine, characterized in that the position of the igniter is adjusted by moving the igniter along the length of the sintering machine based on the measurement result.