JP5699453B2 - Sintering machine and method for producing sintered ore - Google Patents

Description

  The present invention relates to a downward suction type Dwytroid (DL) sintering machine for producing sintered ore and a method for producing sintered ore.

  Sinter ore, which is the main raw material for 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 These raw materials are cut out from each of the plurality of hoppers 1 at a predetermined ratio on a conveyor. The cut out raw material is added with an appropriate amount of water by the drum mixer 2, the drum mixer 3 and the like, mixed and granulated to obtain a sintered raw material which is a pseudo particle having an average diameter of 3.0 to 6.0 mm. The On the other hand, the sized coarse ore is cut out from the floor hopper 4 to form a floor layer on the great of the sintering machine pallet 8.

  The sintering raw material is charged on the floor layer on the endless moving type sintering machine pallet 8 through the drum feeder 6 and the cutting chute 7 from the surge hopper 5 arranged on the sintering machine, and sintered. A charge layer 9 of a sintering raw material, also called a binding bed, is formed. The thickness (height) of the charging layer is usually around 400 to 800 mm. Thereafter, the ignition furnace 10 installed above the charging layer 9 ignites the carbonaceous material in the surface layer of the charging layer 9 and air through a wind box 11 disposed under the pallet 8. Is sucked downward to sequentially burn the carbonaceous material in the charging layer, and the sintered raw material is burned and melted by the combustion heat generated at this time to obtain a sintered cake. The sintered cake thus obtained is then crushed and sized, and recovered as a product sintered ore comprising agglomerates of 5.0 mm or more.

  In the manufacturing process, first, the ignition layer 10 is ignited by the ignition furnace 10. The ignited charcoal in the charging layer continues to burn with a width by the air sucked from the upper layer part of the charging layer toward the lower layer part by the windbox, and the combustion zone gradually becomes lower as the pallet 8 moves. Proceed to. As the combustion progresses, the moisture contained in the sintering raw material particles of the charging layer is vaporized by the heat generated by the combustion of the carbonaceous material, sucked downward, and the lower layer that has not yet risen in temperature is burned. Concentrate in the raw material to form a wet zone. If the moisture concentration exceeds a certain level, moisture fills the gaps between the raw material particles, which are the flow paths of the suction gas, and the ventilation resistance is increased. Note that the melted portion necessary 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 the sintering machine is generally determined by the sintering production rate (t / hr · m ² ) × sintering machine area (m ² ). That is, the production volume of the sintering machine includes the machine width and length of the sintering machine, the thickness of the raw material deposition layer (charge layer thickness), 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. 25 shows the charge layer when the front of the combustion zone moving through the charge layer having a thickness of 600 mm is located approximately 400 mm above the pallet of the charge layer (200 mm below the charge layer surface). This shows the pressure loss and temperature distribution. The pressure loss distribution at this time is about 60% in the wet zone and about 40% in the combustion / melt zone.

FIG. 26 shows the temperature distribution in the charging layer at the time of high production and low production of sintered ore, that is, when the pallet moving speed is fast and slow. 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 in} the case of low production, and in the case of high production with an emphasis on productivity. It is represented by t _2. Since the pallet moving speed is high during high production, the high temperature region holding time t ₂ is shorter than t ₁ during low production. When the high temperature region holding time is shortened, firing is likely to be insufficient, the cold strength of the sintered ore is lowered, and the yield is lowered. Therefore, in order to increase the productivity of high-strength sinter, increase the strength of the sintered cake, that is, the cold strength of the sinter, to maintain and improve the yield even during short-time sintering. It is necessary to take some measures to be able to. In general, SI (shutter index) and TI (tumbler index) are used as indices representing the cold strength of sintered ore.

FIG. 27A shows the progress of sintering in the charging layer on the sintering machine pallet, FIG. 27B 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. 27 (b), 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 and 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
Conventionally, a variety of techniques for improving productivity by improving yield have been proposed.

  For example, in Patent Document 1, hot air of about 300 ° C. is blown to the surface of the charging layer until the sintering raw material is ignited in the ignition furnace after charging the sintering raw material onto the sintering machine pallet, and only the upper portion of the charging layer is sprayed. A method of igniting the thermal shock at the time of ignition by igniting the surface layer of the charged layer that has become high temperature, and preventing deterioration of air permeability due to the destruction of granulated particles and reduction of the production rate due to this Has been proposed.

Moreover, in patent document 2, various gaseous fuel is supplied from the top of the charging layer of the sintering raw material made to volume on the pallet of a sintering machine, the highest ultimate temperature in a charging layer, high temperature holding time, or A method has been proposed in which both are adjusted and a high-strength sintered ore is produced at a high yield without deteriorating the air permeability of the entire charged layer.
Furthermore, in Patent Document 3, during the sintering operation of the fine ore, that is, the sintered raw material is charged and charged onto the pallet or bed of the sintering machine, and after the sintered raw material is ignited, the oil and fat liquid fuel, for example, heavy oil A method for producing a sintered ore has been proposed in which the powdered ore on the surface is sintered hard by spraying the surface of the sintered raw material.

Japanese Patent Publication No.54-24682 JP 2008-95170 A Japanese Examined Patent Publication No. 39-16754

  What is important in quality control of sintered ore is control of the maximum temperature reached during combustion and high temperature holding time, and the quality of sintered ore is determined by these controls. In the conventional example described in Patent Document 2, the maximum temperature reached can be adjusted to 1205-1350 ° C. by blowing gaseous fuel into the upper layer of the charging layer, and the high temperature holding time can be extended. However, the conventional example described in Patent Document 2 is based on the premise that the sinter ore manufacturing plant has an infrastructure of gaseous fuel, and can be applied when supply of gaseous fuel is impossible. There is an unresolved issue that cannot be solved.

Moreover, in the prior art example described in Patent Document 3, it is predicted that heavy oil having a high flash point will remain on the cake surface when sprayed. The oil remaining on the cake surface is expected to cause various harmful effects. For example, when the sintered ore is pulverized, the sintered ore containing red oil may come into contact with the sintered ore containing oil, so that the sintered ore may burn in the process after the crusher. In addition, dust containing oil generated during crushing with a crusher may cause a fire in an electric dust collector (EP). Furthermore, it is known that dust containing oil reduces the dust collection efficiency. In addition, there are unsolved problems such as oil adhering to the crusher and belt conveyor, handling performance deteriorates, and an increase in the number of maintenance is predicted.

  Accordingly, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and is applied when adjusting the maximum temperature reached during sintering and the high temperature holding time using liquid fuel. An object of the present invention is to provide a sintering machine and a method for producing a sintered ore capable of improving the use efficiency of liquid fuel and reducing the amount of liquid fuel remaining on the cake surface.

In order to achieve the above object, a sintering machine according to an embodiment of the present invention includes a pallet that circulates and a sinter raw material containing fine ore and carbonaceous material on the pallet to form a charging layer. A raw material supply device to be formed, an ignition furnace for igniting the carbonaceous material in the sintered raw material on the pallet, and a wind box for sucking air below the pallet, and burning the carbonaceous material in the charging layer A sintering machine for producing a sintered cake by atomizing a liquid fuel having a boiling point of 150 ° C. or more above the charging layer and having a boiling point of 100 μm or less above the charging layer. a liquid fuel injection device for injecting Te, provided above the liquid fuel injector, is injected from the liquid fuel injection device and vaporizing the liquid fuel of less aspirated particle size 100μm to in the sintering bed A hot air supply device for supplying hot air at a temperature that promotes It is characterized by having.

Further, in the sintering machine according to another aspect of the present invention, the liquid fuel injection device includes a compressed gas supply source, a liquid fuel supply source, a compressed gas from the compressed gas supply source, and the liquid fuel supply source. And a spray mechanism for atomizing the liquid fuel and injecting it horizontally onto the charging layer .

Moreover, the sintering machine according to another aspect of the present invention is characterized in that the temperature of the hot air is set in a temperature region that is higher than the flash point of the liquid fuel and lower than the ignition point.
In the sintering machine according to another embodiment of the present invention, the temperature of the hot air is set to a temperature that suppresses the residual oil ratio of the liquid fuel remaining on the surface of the sintered cake to 2% or less. It is a feature.

In the sintering machine according to another aspect of the present invention, the temperature of the hot air is set to a temperature in the range of 88 ° C. or higher and 200 ° C. or lower.
Further, in the sintering machine according to another aspect of the present invention, the liquid fuel is a petroleum liquid fuel, an alcohol liquid fuel, an ether liquid fuel, or other hydrocarbon compound liquid in which the liquid fuel is in a liquid state near normal temperature. It is characterized in that at least one fuel is used.
A sintering machine according to another embodiment of the present invention is characterized in that the liquid fuel is heavy oil.

Further, in the method for producing sintered ore according to one aspect of the present invention, a charged layer is formed by charging a raw material supply device with a sintered raw material containing fine ore and carbonaceous material on a circulating pallet. A sintered ore manufacturing method in which the carbon material in the charging layer is ignited and air is sucked by a wind box disposed below the pallet, The liquid fuel having a boiling point of 150 ° C. or higher is atomized to a particle size of 100 μm or less by the liquid fuel injection device on the downstream side of the ignition furnace and above the charging layer, and the liquid fuel is injected by the hot air supply device. It injected from the injection device, and is characterized by supplying the hot air temperature to promote vaporization to the sintering bed the liquid fuel of less aspirated particle size 100μm to within.
Moreover, the manufacturing method of the sintered ore which concerns on the other form of this invention is characterized by the said liquid fuel being heavy oil.
In the method for producing sintered ore according to another embodiment of the present invention, the temperature of the hot air is set to a temperature at which the residual oil ratio of the liquid fuel remaining on the cake surface is suppressed to 2% or less. It is a feature.

  According to the present invention, on the downstream side of the ignition furnace, the liquid fuel injection device that atomizes the liquid fuel and injects it in the horizontal direction above the charging layer, and the liquid fuel atomized from above the liquid fuel injection device. And a hot air supply device for supplying hot air for promoting vaporization, so that the atomized liquid fuel injected by this liquid fuel injection device is uniformly dispersed on the charging layer, and this uniformly dispersed atomization Since the liquid fuel is sucked into the charging layer together with hot air by the wind box, it is volatilized in the charging layer and, as in the case of using gaseous fuel, the atomized liquid fuel supply position and The maximum temperature and holding time of the high temperature range can be controlled, and sintering not only in the upper part of the charging layer where the cold strength of the sintered ore tends to be low due to insufficient combustion, but also in any part below the middle layer of the charging layer Operate operations to increase ore strength It is possible.

In addition, by atomizing the liquid fuel and injecting it, there is no concern about igniting as in the case of using the liquid fuel as it is, and it is safe to introduce the atomized liquid fuel into the raw material charging layer. And can be carried out stably.
Furthermore, since hot air is supplied to the atomized liquid fuel, vaporization of the liquid fuel can be promoted, and the residual oil ratio of the liquid fuel remaining on the surface of the sintered cake can be greatly reduced.

It is a schematic structure figure showing one embodiment of the present invention. It is typical sectional drawing on the AA line of FIG. It is a front view which shows a spray mechanism. It is a typical perspective view which shows the spray mechanism arrangement | positioning of a liquid fuel injection apparatus. It is explanatory drawing which shows the liquid fuel mist injection state of a liquid fuel injection apparatus. It is a systematic diagram which shows the supply system of the liquid fuel and compressed gas of a liquid fuel injection apparatus. It is a characteristic diagram which shows the vapor pressure curve of A heavy oil. It is sectional drawing on the AA line of FIG. 1 which shows the specific structure of a liquid fuel injection apparatus. It is explanatory drawing which shows the sealing mechanism of the front-back direction of a liquid fuel injection apparatus. It is a schematic diagram which shows the principle at the time of liquid fuel blowing of this invention. It is a figure which shows the combustion condition at the time of liquid fuel blowing of this invention. It is a figure which shows the ignition condition at the time of liquid fuel blowing of this invention. It is a schematic diagram which shows the combustion process of liquid fuel. It is a schematic diagram which shows the combustion state at the time of supplying hot air and cold air to liquid fuel. It is a schematic diagram which shows a pan test state. It is explanatory drawing which shows the relationship between an experiment level and hot air temperature. It is sectional drawing which shows an oil content measuring container. It is explanatory drawing which shows a Soxhlet extractor. It is explanatory drawing which shows the relationship between an experiment level and a residual oil rate. It is a characteristic view which shows the relationship between a production rate and shutter intensity | strength. It is a characteristic diagram which shows the relationship between hot air temperature and shutter intensity | strength. It is a characteristic diagram which shows the relationship between hot air temperature and shutter intensity | strength. It is sectional drawing on the AA line of FIG. 1 which shows other embodiment of this invention. It is a figure explaining the conventional sintering process. 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. It is a graph of the temperature distribution and yield distribution in a sintering machine.

  The manufacturing method of the sintered ore using the sintering machine of this invention is comprised from the charging process, the ignition process, the liquid fuel supply process, and the sintering process. In this manufacturing method, the charging step is a step of charging a sintered raw material containing fine ore and carbonaceous material on a circulating pallet and forming a charging layer of the sintered raw material on the pallet, The ignition step is a step of igniting the carbon material on the upper surface of the charging layer using an ignition furnace. The liquid fuel supply step is a step of injecting the liquid fuel atomized from the liquid fuel injection device into the air above the charging layer in the horizontal direction, and the sintering step is disposed under the pallet. The atomized liquid fuel and hot air at a predetermined temperature are sucked into the charging layer by the suction force of the wind box, and the atomized liquid gaseous fuel is combusted in the charging layer. This is a step of burning the carbonaceous material in the charging layer with the air sucked in, and sintering the sintered raw material with the heat generated by the combustion to produce a sintered cake.

In the present invention, on the downstream side of the ignition furnace, the liquid atomized above the charging layer as described above is injected into the atmosphere in the horizontal direction, thereby atomizing the liquid while suppressing ignition and the like The fuel can be uniformly dispersed on the charging layer and can be volatilized in the charging layer by air suction of the windbox.
FIG. 1 is a schematic configuration diagram showing an embodiment of a sintering machine according to the present invention. In FIG. 1, as in the conventional example described above, iron ore powder, iron mill recovered powder, sintered ore sieving powder, CaO-containing auxiliary raw materials such as limestone and dolomite, granulation aid such as quick lime, coke powder Sintered raw materials such as coal and anthracite are cut out from a plurality of hoppers 1 on a conveyor at a predetermined ratio, and the cut out raw materials are mixed and granulated by adding an appropriate amount of water using a drum mixer 2, a drum mixer 3, etc. The sintered raw material which is a pseudo particle having an average diameter of ˜6.0 mm is stored in the surge hopper 5. On the other hand, the lump ore adjusted to a predetermined particle size is cut out from the bedding hopper 4 to form a bedding layer on the grate of the sintering machine pallet 8.

  Then, the sintered raw material is charged from the surge hopper 5 through the drum feeder 6 and the cutting chute 7 onto the floor layer on the endless moving type sintering machine pallet 8, and the charging layer 9, also called a sintering bed, is formed. Form. The thickness (height) of the charging layer is usually around 400 to 800 mm. Thereafter, the ignition furnace 10 installed above the charging layer 9 ignites the carbonaceous material in the surface layer of the charging layer 9 and air through a wind box 11 disposed under the pallet 8. Is sucked downward to sequentially burn the carbonaceous material in the charging layer.

A liquid fuel injection device 15 that atomizes the liquid fuel on the upper side of the charging layer 9 and injects it in a substantially horizontal direction is disposed downstream of the ignition furnace 10.
One or more liquid fuel injection devices 15 are disposed downstream of the ignition furnace 10 and at any position in the pallet traveling direction in the process in which the combustion / melting zone proceeds in the charging layer 9. The supply of the liquid fuel mist to the inside is preferably performed at a position after ignition of the carbonaceous material in the charging layer 9. One or a plurality of liquid fuel injection devices 15 are disposed downstream of the ignition furnace 10 at any position after the combustion front has traveled below the surface layer. From the viewpoint of adjusting the cold strength, the size, position, and number of arrangements are determined as described later.

As shown in FIG. 2, the liquid fuel injection device 15 includes a hood 16 that covers an upper portion of the sintering machine pallet 8, and an opening 17 having a relatively large area is provided on the upper portion of the hood 16.
As shown in FIGS. 2 and 4, in the hood 16, a compressed air supply pipe 21 and a liquid fuel supply pipe 22 along the conveying direction of the sintering machine pallet 8 are disposed above the charging layer 9. A plurality of, for example, 9 sets, for example, are arranged in parallel with a predetermined interval in the width direction perpendicular to the conveyance direction.

  A spray mechanism 23 is disposed on the lower surface side of each compressed air supply pipe 21 and liquid fuel supply pipe 22 while maintaining a predetermined distance in the conveying direction of the sintering machine pallet 8. The spray mechanisms 23 are arranged in a staggered manner in the transport direction of the sintering machine pallet 8 so that the spray mechanisms 23 adjacent in the width direction of the sintering machine pallet 8 do not face each other. In addition, the number of sets of the compressed air supply pipe 21 and the liquid fuel supply pipe 22 is not limited to nine sets, and it is preferable to arrange a plurality of sets of 3 to 15 sets.

  As shown in an enlarged view in FIG. 3, each spray mechanism 23 includes a vertical pipe 24 connected to the lower surface of the compressed gas supply pipe 21, a mixing unit 25 formed at an intermediate portion of the vertical pipe 24, and the mixing unit. 25 and a lower surface of the liquid fuel supply pipe 22, and a branch injection section 27 that branches in a bifurcated manner in the width direction of the sintering machine pallet 8 disposed at the lower end of the vertical pipe 24. It is configured.

The branch injection unit 27 includes two symmetrical injection nozzle units 28 a and 28 b with the vertical pipe 24 interposed therebetween. From these injection nozzle portions 28a and 28b, a liquid fuel mist 29 atomized into fine particles of, for example, 100 μm or less is injected in a substantially horizontal direction.
Here, the reason why the particle size of the liquid fuel mist 29 is set to 100 μm or less is that when the particle size exceeds 100 μm, a portion remaining in the surface layer portion of the charging layer 9 is generated and starts to burn in the surface layer portion. In addition, it does not contribute to the extension of the high temperature region holding time of the upper layer and the middle layer, which is insufficient in combustion in the charging layer 9, and is wasted.

Further, the particle size of the liquid fuel mist 29 is preferably as small as possible, but since the generation amount decreases as the particle size is decreased, the particle size of the liquid fuel mist 29 is preferably selected as 50 μm or less and 20 μm or more.
When the particle size of the liquid mist 29 is 50 μm or less, the combustion above the charging layer 9 and in the surface layer portion is suppressed, and the liquid mist 29 passes through a crack portion in the sintered cake formed on the surface layer or is sintered. It vaporizes once in the cake, passes through the sintered cake in a gas state, reaches the combustion / melting zone, and burns.

Further, when the particle size is less than 20 μm, the generation amount of the liquid fuel mist 29 is reduced, and by introducing the liquid fuel mist 29 into the charging layer 9, a good effect of extending the high temperature region holding time is exhibited. I can't.
Each of the injection nozzle portions 28a and 28b has an opening angle of, for example, about 85 degrees with respect to the central axis of the vertical pipe 24, which has a slight downward slope that the center line gradually decreases from the vertical pipe 26 toward the tip. Is set to As described above, since the injection nozzle portions 28a and 28b have a slight downward slope, the liquid fuel mist remains as liquid in the injection nozzle portions 28a and 28b when the injection of the liquid fuel mist is finished. All are dripped.

  Further, since the spray mechanisms 23 are arranged in a staggered manner in the conveying direction of the sintering machine pallet 8, the liquid fuel mist 29 injected from the injection nozzle portions 28a and 28b of each spray mechanism 23 is as shown in FIG. In addition, they are uniformly dispersed and injected onto the charging layer 9 without interfering with each other. Then, using the suction force of a wind box (not shown) under the sintering machine pallet 8, the sintered cake generated on the surface layer of the charging layer 9 is introduced to the deep part (lower layer) of the charging layer. The

As shown in detail in FIG. 6, each compressed gas supply pipe 21 is connected to a compressed gas supply pipe 31 via a flow meter FC and a control valve VC on the upstream side of the sintering machine pallet 8. A gas supply source pipe 31 is connected to a compressed gas supply source 32.
The compressed gas supply source 32 includes a storage tank 33 that stores a gas using as a main component any one of nitrogen, carbon dioxide, and water vapor having flame extinguishing properties. The gas stored in the storage tank 33 is compressed by the compressor 34 to be compressed gas, which is stored in the receiver tank 35, and is supplied from the receiver tank 35 to the control valves VC via the compressed gas supply source piping 31. The

  Here, between the receiver tank 35 and the flow meter FC, a main flow path LM in which a control valve VC is inserted, and a bypass flow path that bypasses the control valve VC and supplies a relatively small flow rate of compressed air. LB. The bypass channel LB is in a state in which the liquid fuel mist 29 is not injected from the spray mechanism 23, and a small amount of compressed gas from the receiver tank 35 passes through the bypass channel LB and the flow meter FC to the spray mechanism 23. The nozzles 28a and 28b of the spray mechanism 23 are prevented from being clogged.

  Similarly, each liquid fuel supply pipe 22 is connected to the liquid fuel supply source pipe 36 via the flowmeter FF and further via the control valve VF on the upstream side of the sintering machine pallet 8. It is connected via a fuel supply pump 37 to a liquid fuel storage tank 38 as a liquid fuel supply source. Here, each of the liquid fuel supply pipe 22 and the liquid fuel supply source pipe 36 is arranged to be inclined in a descending gradient in which the arrangement height on the downstream side is lower than that on the upstream side, and the injection of the liquid fuel mist 29 is finished. It is preferable that the liquid fuel is not left in the liquid fuel supply pipe 22 and the liquid fuel supply pipe 36 when the liquid fuel is supplied.

As the liquid fuel, at least one of petroleum liquid fuel that becomes liquid at room temperature, alcohol liquid fuel such as ethyl alcohol and methyl alcohol, ether liquid fuel, and other hydrogen oxide liquid fuel is used. Considering the ease of supply, A heavy oil or C heavy oil is preferable, and in this embodiment, a case where A heavy oil is used will be described.
Here, the liquid fuel that can be used in the present invention and its characteristics are shown in Table 1 below.

  The liquid fuel mist 29 for atomizing and injecting such liquid fuel has an ignition temperature of blast furnace gas, coke oven gas, blast furnace / coke oven mixed gas, city gas, natural gas or methane gas, ethane gas, propane gas, butane gas, or Since the ignition temperature is higher than that of any gaseous fuel of these mixed gases, the temperature is higher than the temperature of the charged layer 9, that is, the surface layer of the sintered bed, and burns inside the charged layer 9. Therefore, it is effective for expanding the temperature of the combustion / melting zone at the blowing position. In particular, the effect is large when the ignition temperature is close to 500 ° C.

In addition, it is desirable that a large amount of liquid fuel mist 29 can be supplied to the position of the low yield portion in the vicinity of the left and right sidewalls 18 of the hood 16.
In addition, since waste oil etc. may contain the component which is easy to ignite, and the component with low ignition temperature, it is unpreferable for using by this invention. When liquid fuel such as waste oil containing a component having a low ignition temperature or flash point is vaporized in advance and supplied onto the charging layer 9, that is, the sintering material bed, it reaches the vicinity of the combustion zone in the charging layer 9. Since it burns in the upper space of the surface layer of the previous charge layer 9 or in the vicinity of the surface layer of the charge layer 9, it is burned in the vicinity of the combustion zone of the charge layer 9 intended by the present invention to extend the high temperature holding time. This is because the effect cannot be obtained.

  Moreover, in the said embodiment, the spray mechanism 23 which injects the liquid fuel mist 29 demonstrated the case where liquid fuel was mixed with compressed gas by the mixing part 25, atomized, and injected on the charging layer 9 in the horizontal direction. However, the present invention is not limited to this, and the liquid fuel mist obtained by mixing the compressed gas and the liquid fuel supplied from the compressed gas supply source 32 and the fuel supply pump 37 with a mixer is supplied to each spray mechanism via the mist supply pipe. You may make it supply to 23 branch injection parts 27. In this case, it is preferable to maintain the liquid fuel mist at a temperature not lower than the ignition temperature and lower than the ignition temperature so that the liquid fuel mist does not re-liquefy.

And in this invention, the food | hood 16 which covers the upper part of the sintering machine pallet 8 is provided. Connected to the upper opening 17 of the hood 16 is a hot air supply device 40 for supplying hot air that promotes vaporization of the liquid fuel mist 29.
The hot air supply device 40 includes a heater 41 having a heater or a combustion burner that heats the circulating gas to a predetermined temperature to form hot air. The circulating gas is heated to a predetermined temperature by the heater 41 and supplied to the opening 17 of the hood 16 as hot air.

Here, the hot air temperature of the heater 41 is controlled to a predetermined temperature by the temperature control device 42. Therefore, a temperature detection value T of a temperature sensor 43 that detects the hot air temperature on the outlet side of the heater 41 is input to the temperature control device 42, and a heater or a combustion burner is used so that the temperature detection value T becomes a predetermined temperature. To control.
Here, the temperature of the hot air is preferably a temperature in the range of the flash point and the ignition point of the liquid fuel. As described above, when the heavy oil A is used as the liquid fuel, the pen flash rumen sealed flash point (PM). Is 60 to 120 ° C. and the ignition point is about 240 ° C., the temperature is set within this range.
More preferably, the liquid fuel mist 29 is vaporized so that the residual oil rate remaining on the surface layer of the sintered cake is less affected by the residual oil, for example, 2% or less by the liquid fuel mist 29 injected by the liquid fuel injection device 15. Is set to a temperature that can be accelerated.

As will be described later, the hot air temperature at which the residual oil ratio remaining on the surface layer of the sintered cake becomes 2% is 88 ° C. close to the flash point. When the hot air temperature is raised from 88 ° C., the residual oil rate of the sintered cake surface layer decreases accordingly, and when the hot air temperature becomes 200 ° C. close to the ignition point, the residual oil rate of the sintered cake surface layer becomes 0%, There is no oil content on the surface of the sintered cake.
Here, when A heavy oil (produced by Tarakan Oil Field) is used as the liquid fuel, the vapor pressure curve representing the relationship between temperature (° C.) and vapor pressure (mmH ₂ O) is as shown in FIG. Become.
From FIG. 7, the vapor pressure at equilibrium is about 8 times the flash point and about 40 times the vapor pressure near 200 ° C. than the normal temperature.

According to the literature (Yamagata University Bulletin, Engineering, Vol. 11, No. 1, Showa 45 (S45)), if the temperature is T, the evaporation rate k is expressed by the following equation (1). Is done.
k = exp (−2406.8 / T + 2.7867) (1)
As is apparent from the equation (1), the evaporation rate k = 0.005 (cm ⁻² · min ⁻¹ ) at normal temperature (25 ° C.), and k = 0.140 (cm ⁻² · min ⁻ ) at 200 ° C. ¹ ).
The residual oil ratio m at this time is represented by the following formula (2).
m = 1-klog (t) (2)
Here, t is a holding time (min).

Since the blowing time is the same, assuming that the reaction interface area is constant, assuming that the heavy oil A does not flow as a mist, if the residual oil at room temperature is 10%, 200 ° C. The residual oil is 8.4% when hot air is blown.
In addition, a gap is inevitably generated between the lower side of the hood 16 and the surface of the sintered bed (the surface of the charging layer), but if the gap is not sufficiently sealed, for example, the transmittance is 20 to 20%. When it was 30%, it was found that air was engulfed from this portion into the hood 16 and the concentration distribution of the liquid fuel mist was increased. Therefore, it is important to prevent air from entering from the lower end of the hood 16.

  Therefore, between the lower ends of the left and right sidewalls 18 along the conveying direction of the sintering machine pallet 8 of the hood 16 and the pallet sidewalls 8a, the lower surface of the branch injection portion 27 of the spray mechanism 23, and the upper surface of the charging layer 9 As shown schematically in FIG. 8, a wiper seal 41 having a seal sheet interposed between wire brushes extending in the conveying direction of the sintering machine pallet 8 is installed, and the wiper seal 41 is covered outside from the outside. A cover 42 is provided. The seal material is not limited to the wiper seal 41, and seal materials such as a chain curtain, a seal brush, and a close seal can be applied. Moreover, it is preferable that the sealing material is heat resistant, flexible or has a high degree of freedom of deformation, and does not damage the surface of the charging layer 9.

On the other hand, between the lower end of the front and rear plate portions 16b of the hood 16 and the surface of the charging layer 9 on the upstream side and the downstream side in the conveying direction of the sintering machine pallet 8, the front and rear walls of the hood 16 as shown in FIG. It is preferable to form an air curtain 44 by disposing an air passage 43 along 19 and ejecting air from below the air passage 43.
Further, the installation position, size, and number of arrangements of the liquid fuel injection device 15 are set as follows.
That is, after the carbon material in the charging layer 9 is ignited, the liquid fuel mist 29 is supplied (introduced) onto the charging layer 9. The reason for this is that even if the liquid fuel mist 29 is supplied at a position immediately after ignition, it only burns on the surface layer of the charging layer 9, and the liquid fuel mist does not affect the combustion layer at all. . Therefore, it is necessary to supply the liquid fuel mist to the charging layer 9 after the sintering raw material on the upper part of the charging layer 9 is fired to form a sintered complete band which is a layer of a sintered cake.

The principle of using the liquid fuel mist of the present invention will be described with reference to FIG. FIG. 10A is a photograph when ethanol is used in a pan test with a particle size of about 50 μm. It can be seen that the combustion melting zone greatly expands with ethanol blowing. FIG. 10B schematically illustrates this phenomenon, and the left side in the figure indicates the sintering reaction when the gaseous fuel is diluted and blown. The coke, which is a coagulant, is ignited in an ignition furnace, and the sintering reaction of the powder coke progresses downward while descending the charging layer of the sintering raw material. A sintered zone is formed in a sintered zone, and when a gaseous fuel is diluted and injected between the sintered zone and the powder coke combustion zone, a gas combustion zone of diluted gas is generated. It is responsible for extending the high temperature range holding time without increasing the maximum temperature. The right side shows the sintering reaction when the liquid fuel mist according to the present invention is used. Gasification of the liquid fuel mist occurs in the sintering completed zone. Therefore, in the present invention, as described above, the particle size of the liquid fuel mist is set to 100 μm or less, preferably 50 μm or less. If the particle size exceeds 100 μm, the heat in the sintering complete zone is used to leave droplets, which may cause combustion at the surface layer. When the particle size of the liquid fuel mist is 100 μm or less, the liquid fuel mist (liquid fuel particles) is gasified including the agglomerated particles to become liquid fuel vapor, and between the sintering completed zone and the powder coke combustion zone. When a liquid fuel is blown in as a liquid fuel mist, a gas combustion zone of liquid fuel gas is generated, where the high temperature region holding time is expanded and extended without increasing the maximum temperature, and the same phenomenon as the use of gaseous fuel is exhibited.

When injecting liquid fuel, the gasification (liquid fuel vapor) region of liquid fuel particles shown in FIG. 10B is important.
That is, in the liquid fuel gasification region of FIG. 10B, it is important to first spray the liquid fuel from the spray nozzle so that the vapor concentration of the liquid fuel is equal to or lower than the lower combustion limit concentration of Table 1. . When blowing, it is necessary to make it 75% or less of the lower combustion limit concentration so as not to burn in the surface layer part of the sintering completed zone, and the lower limit is at least 1% of the lower combustion limit concentration in order to utilize fuel heat. To do. Preferably, it is 25% or less and 4% or more of the lower limit concentration of combustion. The upper limit is determined from the safety of fire and the lower limit is determined from the effective heat. Moreover, it is necessary to be below the ignition temperature.

  As shown in FIG. 10 (c), the point of combustion is that the maximum temperature in the sintering reaction is controlled on the powder coke side A, and the high temperature region retention time is the liquid fuel side B that maintains the combustion zone temperature below the maximum temperature. Is burning. An example is shown in FIG. The temperature curve shown as C is an in-layer temperature history during sintering production in a sintering reaction when only powder coke is used as a coagulant. The maximum temperature is controlled by the amount of powder coke, and the high temperature range holding time E is determined by this temperature pattern. When extending the high temperature range holding time with this C temperature pattern, it is necessary to increase the amount of powder coke added to expand the base of the high temperature range of 1200 ° C or higher, but at the same time, it is necessary to increase the maximum temperature. was there. The temperature pattern when using liquid fuel is shown as D. As shown in FIG. 10 (c), the combustion of the liquid fuel is the combustion on the liquid fuel side B in FIG. 10 (c) that maintains the combustion zone temperature below the maximum temperature. The combination of the two results in the temperature pattern D in FIG. 10D in which the temperature in the base region is increased without changing the maximum temperature. With this temperature pattern D, the base of the region of 1200 ° C. or higher is expanded, and the high temperature region holding time F is secured.

FIG. 11 is a photograph of a pan test of a conventional sintering method and a sintering method using a liquid fuel mist. In conventional sintering, the powder coke ratio is high due to the utilization of combustion heat of powder coke. In addition, the combustion / melting zone that appears white even when the height is high is approximately 65 mm in this experiment.
In the liquid fuel gasification zone (sintering completion zone), the temperature of the zone is higher than the boiling point of the liquid fuel and lower than the ignition temperature (can be controlled by lowering the concentration below the lower combustion limit concentration). Examples of heavy oil and ethanol are shown, but the amount of powder coke used was reduced in order to keep the maximum temperature at 1380 ° C. In both cases, the burning / melting zone that looks white was expanded, and the obtained sintered ore strength was higher than that of the conventional sintering method using only powdered coke.

Further, in the gasification region (sintering completion zone) of the liquid fuel in FIG. 10B, the temperature of the region needs to be not less than the boiling point of the liquid fuel and not more than the ignition temperature. By doing so, the phenomenon shown in FIG. 11 is obtained.
When the temperature of the gasification region (sintering completion zone) is equal to or higher than the ignition temperature (high concentration close to the lower combustion limit concentration), the surface of the sintering completion zone before entering the powder coke combustion zone as shown in FIG. In this case, the liquid fuel vapor is burned, the effect is lost, and oxygen is insufficient. This adversely affects the sintering operation.

The liquid fuel mist can be supplied at an arbitrary position until the sintering is completed as long as a sintered cake layer is formed on the surface of the charging layer 9. The reasons other than the above, in which the liquid fuel mist is supplied after the sintered cake layer is formed, are as follows.
(A) If the liquid fuel mist is supplied in the state immediately after ignition in which no sintered cake is formed on the top of the charge layer 9, there is a possibility of burning on the charge layer 9.
(B) It is preferable to supply the liquid fuel mist to a portion where it is necessary to improve the yield of the sintered ore, that is, to supply combustion at a portion where it is desired to increase the strength of the sintered ore.

In order to adjust either or both of the charged layer maximum cylinder temperature and the high temperature region holding time, the thickness of the combustion / melting zone is at least 15 mm or more, preferably 20 mm or more, more preferably 30
It is preferable to supply the liquid fuel mist in a state where it is equal to or greater than mm. When the thickness of the combustion / melting zone is less than 15 mm, the cooling effect by the air sucked through the sintered layer (sintered cake) and the liquid fuel mist causes the effect to be insufficient even if the liquid fuel mist is burned. This is because the thickness of the melting zone cannot be increased. On the other hand, when the liquid fuel mist is supplied at a stage where the thickness of the combustion / melting zone is 15 mm or more, preferably 20 mm or more, more preferably 30 mm or more, the thickness of the combustion / melting zone is greatly expanded, and the high temperature region holding time is increased. It can be extended, and as a result, a sintered ore with high cold strength can be obtained.

The liquid fuel mist is introduced into the charging layer 9 at a position where the combustion front is lowered below the surface layer and the combustion / melting zone is lowered from the surface layer by 100 mm or more, preferably 200 mm or more, that is, in the charging layer 9 It is preferable that the sintered cake region (sintered layer) generated in the lower layer passes through without burning, and is supplied so as to burn when the combustion front moves 100 mm or more from the surface layer. The reason is that if the combustion front is at a position lower than the surface layer by 100 mm or more, the adverse effect of cooling by the air sucked through the sintered layer is reduced, and the thickness of the combustion / melting zone can be increased. . Furthermore, if the combustion / melting zone is at a position 200 mm or more lower than the surface layer, the influence of cooling by air is substantially eliminated, and the thickness of the combustion / melting zone can be increased to 30 mm or more. The supply of the liquid fuel mist is more preferably performed in the vicinity of the sidewalls of the both pallet width direction coal portions where the yield reduction is large.
The liquid fuel injection device 15 differs depending on the size of the sintering machine. For example, in a sintering machine having a production amount of about 15,000 t / day and a length of 90 m, the ignition furnace 10 It is preferable to arrange at a position about 5 m or less downstream.

  In the sintering machine according to the present invention, the liquid fuel mist supply position (introduction position to the charging layer) is the exit side of the ignition furnace 10 in the pallet traveling direction, and a so-called combustion front after the sintered cake is formed. It may be carried out at one or more arbitrary positions from the position that has progressed below the surface layer (for example, the position at which the liquid fuel mist burns below 100 mm, preferably about 200 mm or less) to the completion of sintering. preferable. This means that, as described above, the introduction of the liquid fuel mist is started when the combustion front moves below the surface of the charging layer, and as a result, the combustion of the liquid fuel mist is started. This means that there is no risk of explosion and a safe sintering operation is possible.

  In the method for producing a sintered ore according to the present invention, the introduction of the liquid fuel mist into the charging layer also means that the reheating of the produced sintered cake is promoted. That is, this liquid fuel mist is originally supplied with a liquid fuel mist that is more reactive than solid fuel to a portion where the cold strength of the sinter is low and the cold strength of the sintered ore is likely to be short of heat. This is because the heat of combustion in this portion that is likely to be deficient is compensated for, and the regeneration / expansion of the combustion / melting zone is assumed.

Further, in the method for producing sintered ore according to the present invention, the supply of the liquid fuel mist from the upper part of the charged layer after ignition is such that at least a part of the introduced liquid fuel mist in the charged layer remains unburned. It is preferable to reach the combustion / melting zone and burn at a target position where combustion heat is to be compensated. It is thought that it is more effective to spread the liquid fuel mist supply, that is, the introduction effect into the charging layer not only to the upper part of the charging layer but also to the combustion / melting zone which is the central part in the thickness direction. Because. In other words, if the supply of liquid fuel mist is performed in the upper layer of the charging layer, which is prone to heat shortage (insufficient holding time in the high temperature range), sufficient combustion heat is provided, and this portion of the sintered cake In addition, if the liquid fuel mist supply action extends to the zone below the middle layer, recombustion / melting with liquid fuel mist on top of the combustion / melting zone with the original carbon material This results in the same result as forming a band, leading to a widening of the combustion / melting zone in the vertical direction, so it is possible to extend the holding time of the high temperature range without increasing the maximum temperature, so the moving speed of the pallet This is because sufficient sintering can be realized without dropping the thickness. As a result, the quality of the sintered cake of the entire charged layer is improved (improving the cold strength), and consequently the quality (cold strength) and productivity of the product sintered ore are improved.

Further, in the present invention, when the liquid fuel mist is introduced (supplied) into the charging layer, not only the supply position thereof is adjusted, but also the form of the combustion / melting zone itself is controlled. It is preferable to control the maximum temperature reached in the melting zone and / or the high temperature region holding time.
In general, in the charged layer after ignition, the combustion (flame) front gradually expands downward and forward (downstream) as the pallet moves, and the position of the combustion / melting zone is as described above with reference to FIG. It changes as shown in (a). And as shown in FIG.27 (b), the thermal history received in the sintering process in a sintered layer differs in an upper layer, a middle layer, and a lower layer, and it is high temperature range holding time (about 1200 degreeC or more with an upper layer-a lower layer). Time) is very different. As a result, the yield of sintered ore by position in the pallet shows a distribution as shown in FIG. That is, the yield of the surface layer portion (upper layer portion) is low, and the yield distribution is high in the middle layer and the lower layer portion. Therefore, when the liquid fuel mist is supplied according to the method of the present invention, the combustion / melting zone expands in the vertical thickness, the width in the pallet traveling direction, and the like, which is reflected in the quality improvement of the product sintered ore. . And since the intermediate | middle layer part and lower layer part which become high yield distribution can control high temperature range holding time, it can raise a yield more.

  By adjusting the supply (introduction) position of the liquid fuel mist, the form of the combustion / melting zone, that is, the thickness in the height direction of the combustion / melting zone and / or the width in the pallet traveling direction can be controlled, and the maximum Achieving temperature and high temperature range holding time can be controlled. These controls make the effects of the present invention stand out more and are always sufficient through expansion of the vertical thickness of the combustion / melting zone and the width of the pallet traveling direction, and control of the maximum temperature reached and the high temperature range holding time. Performs firing and contributes effectively to improving the cold strength of the sintered product ore.

  In the present invention, it can also be said that the supply (introduction) of the liquid fuel mist into the charging layer is for controlling the cold strength of the entire product sintered ore. In other words, the original purpose of supplying the liquid fuel mist is to improve the cold strength of the sintered cake and eventually the sintered ore. The cold strength (shutter index SI) of the sintered ore is about 75 to 85%, preferably 80% or more, more preferably 90% through the control of the high temperature range holding time, which is the time spent in the belt, and the control of the maximum temperature reached. That's it.

  In the present invention, this strength level is particularly in consideration of the concentration of the liquid fuel mist, the supply amount, the supply position and the supply range, preferably considering the amount of carbonaceous material in the sintered raw material (under the condition that the input heat amount is constant). By adjusting above, it can be achieved inexpensively. On the other hand, the improvement of the cold strength of sintered ore may lead to an increase in ventilation resistance and a decrease in productivity. In the present invention, such problems are also controlled by controlling the maximum temperature and holding time in the high temperature range. In order to solve this problem, the cold strength of the sintered ore is improved. In addition, the cold strength SI value of the sintered ore manufactured by the real machine sintering machine shows a value 10-15% higher than the value obtained by a pan test.

  In the production method of the present invention, the introduction position of the liquid fuel mist in the charging layer in the pallet traveling direction is a sintered ore in an arbitrary zone between the sintered cake formed in the charging layer and the wet zone. It is based on how to make the cold strength of. For this control, in the present invention, the scale (size), number, position (distance from the ignition furnace) and gas concentration of the liquid fuel injection device, preferably the amount of carbonaceous material (solid fuel) in the sintered raw material By adjusting according to the above, not only the size of the combustion / melting zone (the thickness in the vertical direction and the width in the pallet traveling direction) but also the high temperature reached temperature and the high temperature range holding time are controlled. Controls the strength of the sintered cake formed in the charge layer.

Next, the operation of the above embodiment will be described.
First, as shown in FIG. 1, the granulated ore from the floor hopper 4 is cut out to form a floor layer on the great of the sintering machine pallet 8, and the surge hopper 5 to the drum feeder are formed on the floor layer. The sintered raw material quantitatively cut out in 6 is charged to form a charging layer 9 of about 400 to 800 mm, which is also called a sintering bed.
Then, as the sintering machine pallet 8 is conveyed, the carbonaceous material in the surface layer of the charging layer 9 moved under the ignition furnace 10 is ignited.
In the charged layer 9 after ignition, the combustion (flame) front gradually expands downward and forward (downstream) as the sintering machine pallet 8 moves, and the position of the combustion / melting zone is as described above. It changes as shown in FIG. Then, when the position of the combustion / melting zone reaches about 200 mm from the surface layer that shifts from the upper layer to the middle layer, the sintering machine pallet 8 reaches the position of the liquid fuel injection device 15.

In this liquid fuel injection device 15, as shown in FIG. 2, hot air controlled at a constant temperature, for example, 200 ° C. by a temperature control device 42 from a heater 41 of the hot air supply device 40 is supplied to the opening 17 at the top of the hood 16. Has been.
In the liquid fuel injection device 15, the liquid fuel mist 29 is uniformly injected onto the surface of the charging layer 9 by the spray mechanism 23 in the hood 16 that covers the top of the sintering machine pallet 8.

  That is, in the liquid fuel injection device 15, the compressed gas supply pipe 22 extending in parallel with the conveying direction of the sintering machine pallet 8 and the liquid fuel at a position away from the surface of the charging layer 9 of the liquid sintering machine pallet 8 by a predetermined distance. A predetermined number of sets of supply pipes 22 are arranged in the width direction perpendicular to the conveying direction, and compressed gas and liquid fuel are mixed into each set of compressed gas supply pipes 21 and liquid fuel supply pipes 22 and atomized to 100 μm or less. A spray mechanism 23 for injecting the liquid fuel as a liquid fuel mist in a substantially horizontal direction is disposed.

  And, as shown in FIG. 5, this spray mechanism 23 is arranged with a half-pitch shift in the conveying direction of the sintered pallet 8 so that the adjacent spray mechanisms 23 do not face each other, A uniform injection region is formed without the liquid fuel mists 29 injected from the injection nozzle portions 28a and 28b of the spray mechanism 23 in adjacent groups interfering with each other.

  The injected liquid fuel mist 29 is mixed with hot air rectified by the rectifying plate 40 and diluted below the lower limit concentration of combustion at room temperature, and combustion above the charging layer 9 can be suppressed. At this time, at least one of nitrogen, carbon dioxide gas, and water vapor having flame extinguishing properties is used as a main component as atomizing gas for atomizing the liquid fuel, and the liquid fuel mist 29 has such flame extinguishing properties. Since compressed gas is contained, it can suppress reliably that the liquid fuel mist 29 is burned by the upper side of the charging layer 9. FIG.

Then, the liquid fuel mist 29 injected from the injection nozzle portions 28a and 28b of each spray mechanism 23 is sucked downward together with the hot air through the wind box 11 disposed below the sintering machine pallet 8. Thus, it is introduced into the charging layer 9.
At this time, as shown in FIG. 13, the liquid fuel mist 29 injected from the injection nozzle portions 28a and 28b of the spray mechanism 23 is evaporated and accelerated by hot air heated to 200 ° C., for example. Then, it is mixed with the air supplied from the subsequent stage in the charging layer 9 to become a combustible air-fuel mixture.

The combustible air-fuel mixture introduced into the charging layer 9 reaches the lower explosion limit concentration, passes through the sintered cake generated in the surface layer portion, and reaches the combustion / melting zone 100 mm or more below the surface. In this combustion / molten layer, it is burned. For this reason, the high temperature region holding time is originally short and heat is likely to be insufficient, and the high temperature region holding time for maintaining the upper and middle layer regions where the cold strength of the sintered ore is low at a high temperature region of 1200 ° C. or higher can be increased. The cold strength of the ore can be improved. Therefore, it is possible to improve the yield of the upper / middle layer portion with a low yield shown in FIG. 27C when the liquid fuel mist 29 is not blown.

  Moreover, since the liquid fuel mist 29 injected from the spray mechanism 23 is vaporized by hot air, no oil remains on the surface of the sintered cake. For this reason, when a large amount of oil remains on the surface of the sintered cake, the sintered ore burns in the process after the crusher described above, dust containing oil causes a fire in the electric dust collector (EP), Various problems such as deterioration of handling performance and increase in the number of maintenance due to adhesion to the crusher and belt conveyor can be surely solved.

  Further, since the liquid fuel mist 29 injected from the spray mechanism 23 is evaporated by hot air and evaporated to become a combustible gas, at this time, when the liquid fuel mist 29 evaporates, it evaporates from the preheating of the charging layer 9. It will take away latent heat. However, it is possible to compensate for the heat taken away by the latent heat of vaporization with hot air, and that the surface layer of the charging layer 9 is cooled when introduced into the charging layer 9 as shown in FIG. This can be suppressed and does not affect the combustion in the charging layer 9.

  Incidentally, as shown in FIG. 14B, when air near normal temperature, that is, cold air, is sucked from the opening 17 of the hood 16 instead of hot air, the air is injected from the spray mechanism 23 because the air temperature is relatively low. Since the combustible air-fuel mixture mixed with air or the liquid fuel mist 29 is introduced into the charging layer 9, it compensates for the preheating of the charging layer 9 taken away by the latent heat of vaporization when the sharp gas fuel mist 29 evaporates. The surface layer of the charging layer 9 is cooled, and the liquid fuel remains.

  In this way, when the supply operation of the liquid fuel mist 29 extends to the region below the middle layer, a recombustion / melting zone by the liquid fuel mist 29 is formed on the combustion / melting zone by the original carbon material. Results in equal expansion and expansion of the combustion / melting zone in the vertical direction, so that it is possible to extend the holding time of the high temperature region without increasing the maximum temperature, so the moving speed of the sintering machine pallet 8 is reduced. Sufficient sintering can be realized without this. As a result, the quality of the sintered cake of the charging layer 9 as a whole (improvement of cold strength) is brought about, leading to improvement of the quality (cold strength) and productivity of the sintered ore.

When the supply of liquid fuel to the fuel supply pipe 21 is started and when the supply of liquid fuel is stopped, the heated gas is supplied as a purge gas to the liquid fuel supply pipe 21 to burn the liquid fuel remaining in the pipe It is preferable to remove them.
In order to confirm the effect of this embodiment mentioned above, the hot air blowing experiment was done.
In this hot air blowing experiment, as shown in FIG. 15, a cylindrical iron pan 50 (290 mmφ × 400 mmH) is used, and a sintered raw material containing iron ore, a solvent, and powder coke is drummed inside the iron pan 50. The granulated particles 51 granulated with a mixer are filled. Table 2 below shows specific raw material blends other than coke.

In carrying out this blending, the silica in the sintered raw material was set to 4.9% and the basicity was set to 2.0. In addition, the amount of powdered coke is changed for each experimental level.
In the experiment, a blower is basically installed below the sintered layer, and air is drawn from the upper layer of the charging layer. Level (T2) for blowing mist-like A heavy oil in addition to air (T3, T4) for blowing mist-like A heavy oil and hot air at 160 ° C. (about 9 times the vapor pressure at normal temperature) ), Level (T5, T6) (invention) for blowing A heavy oil and mist-like A heavy oil and 200 ° C. (vapor pressure about 14 times the normal temperature order) and level for blowing liquefied natural gas (LNG) in addition to air The experiment of (EX1) (comparative example) was conducted.

FIG. 16 shows a specific example of each level. Coke as a carbonaceous material in the raw material is 5 mass% as a standard. When heavy oil A is blown, coke is reduced to 4.2 mass% and liquefied natural gas is blown to avoid giving excessive heat to the sintered layer. In some cases, the coke was reduced to 4.7 mass%.
Further, at levels T3 to T6 corresponding to the present invention, A heavy oil and hot air were simultaneously blown in 30 seconds after the ignition of the sintered raw material layer.
Here, at levels T3 and T4, the amount of A heavy oil blown is set to 5.4 (g / min) and 2.8 (g / min). At levels T5 and T6, the flow of A heavy oil is reversed. The amount was set to 2.8 (g / min) and 5.4 (g / min). At level EX1, the amount of liquefied natural gas blown was set to 0.4%.

And mass balance evaluation of A heavy oil in experiment was performed, and the combustion amount in a combustion zone was computed.
Combustion amount in the combustion zone = α-β-γ
However, (alpha) is the supply amount of A heavy oil, and measured A heavy oil tank weight. β is the residual amount of the ignition furnace, and was measured by wiping the inside of the ignition furnace with a waste cloth. γ is the residual amount on the top surface of the cake, and the top surface of the cake was collected and measured for oil (dissolved and separated with acetone).
At this time, the oil content was measured by weighing a sample collected from the upper surface of the cake, inserting the sample 56 into the cylindrical filter paper 55 shown in FIG.
This cylindrical filter paper 55 is set in a Soxhlet extractor 58 shown in FIG. 18, the oil is dissolved in acetone at 80 ° C., the filtrate is heated, the acetone is evaporated to collect the oil, and the weight of the collected oil Was measured.
The experimental results are shown in Table 3 below.

As is apparent from Table 3, the residual oil rate on the sintered cake surface was 3.31% at the level T2 when hot air was not blown, as shown in FIG. In the level T3 of the present invention, the residual oil ratio is 0.31%, and the residual oil content on the surface of the sintered cake is reduced to 1/10 or less. Moreover, at the level T4 where the A heavy oil blowing amount is about half at the same hot air temperature (160 ° C.) as the level T3, the residual oil ratio is 0%, and at the levels T5 and T6 where the hot air temperature is 200 ° C., the A heavy oil blowing is performed. Regardless of the amount, the residual oil ratio was 0%, and no residual oil was observed on the surface of the sintered cake.
In addition, the shutter strength (%) of the product, the product yield (%), the sintering time (min), the production rate (t / h · m ² ), and the production amount (kg) according to the experiments of the above levels T2 to T6 and EX1. Table 4 below shows the results of calculating the injection basic unit (kg / ts) and the unit price (total fuel: yen / ts).

As is apparent from Table 4, the cold strength (shutter strength) and the product yield are significantly higher at levels T3 to T6 where the heavy oil A and hot air are blown simultaneously compared to the level T2 where only the heavy oil A is supplied. It has improved.
In particular, the relationship between the shutter intensity and the production rate is as shown in FIG. 20, and when only A heavy oil is used, the production rate and the shutter intensity are both low, whereas the shutter intensity is 76% or less. When supplying 160 ° C. hot air to A heavy oil, the shutter strength can be improved to 80% and the production rate can also be improved. Furthermore, when supplying 200 degreeC hot air to A tree oil, a production rate can be improved, maintaining a sitter intensity | strength at 80%.

By the way, when the relationship between the hot air temperature and the shutter strength is expressed by using the amount of A heavy oil blown as a parameter, the relationship between the hot air temperature and the shutter strength is as shown in FIG. 21, and when the hot air temperature exceeds 160 ° C., the improvement range of the shutter strength decreases. When the blowing amount of A heavy oil is 5.4 (g / min), there is almost no improvement in the shutter strength when the temperature exceeds 160 ° C.
On the other hand, as another comparative example, the relationship between hot air temperature and shutter strength when only hot air was blown without blowing A heavy oil was tested, and the results shown in Table 5 below were obtained.

FIG. 22 shows the relationship between the hot air temperature and the shutter strength in the experimental results of Table 5.
As is apparent from FIG. 22, the shutter strength is 76.3% at room temperature (26 ° C.), which is higher than when 5.4 (g / min) of A heavy oil and hot air are blown. In the case where only the hot air temperature is supplied, the improvement range of the shutter strength is small compared to the increase in the hot air temperature, and in the high temperature region where the hot air temperature exceeds about 60 ° C., the shutter strength is higher than that in the case where the heavy oil A and the hot air are blown. It was confirmed to be smaller.
As a result, it was confirmed that the shutter strength was not improved only by supplying hot air, but the shutter strength in the 80% range could be obtained for the first time by combining A heavy oil and hot air.

  Thus, in the above-described embodiment, after the surface layer of the charging layer 9 is ignited by the ignition furnace 10, the liquid fuel mist 29 is uniformly placed on the upper side of the charging layer 9 of the sintering machine pallet 8 by the liquid fuel injection device 15. Liquid fuel with a high ignition temperature is used compared with the case of using diluted gaseous fuel obtained by diluting and injecting gaseous fuel such as propane gas, LNG, M gas, etc. This liquid fuel is not used as it is, but is atomized with compressed gas and injected as liquid fuel mist, so that the possibility of ignition on the upper side of the charging layer 9 can be reliably suppressed. In addition, by using a gas mainly containing at least one of nitrogen, carbon dioxide, and water vapor having flame extinguishing properties as the compressed gas, it is possible to further suppress the risk of ignition on the upper side of the charging layer 9.

Further, since the vaporization of the liquid fuel mist 29 injected from the spray mechanism 23 by the hot air is promoted, it is possible to prevent or suppress the liquid fuel from remaining on the surface layer of the charging layer 9, and to prevent the liquid on the surface layer of the sintered cake. Various harmful effects caused by the remaining fuel can be eliminated.
In the above-described embodiment, the case where the liquid fuel injection device 15 is disposed on the downstream side of the ignition furnace 10 has been described. However, the present invention is not limited to this, and a heat insulation furnace is disposed on the downstream side of the ignition furnace 10. In such a case, the liquid fuel injection device 15 may be disposed on the downstream side of the heat retaining furnace.

  Moreover, in the said embodiment, although the case where the baffle plate 40 was provided in the hood 16 of the liquid fuel injection apparatus 15 was demonstrated, it is not limited to this, As shown in FIG. A baffle plate 51 having a cross-sectional shape extending in the conveying direction of the sintering machine pallet 8 between the walls 19 and having the apex upward is maintained at a predetermined pitch p in the width direction perpendicular to the conveying direction of the sintering machine pallet 8. Three baffle plate rows 52 having a configuration in which a predetermined number of them are arranged in parallel are arranged in the vertical direction, and between the baffle plate rows 52 adjacent in the vertical direction, the baffle plates 51 in one baffle plate row 52 are arranged in the other baffle plate 51. The baffle plate 51 of the plate row 52 may be disposed so that the spray mechanism 23 is arranged between the baffle plates 51 on the lower side of the lowermost baffle plate row 52.

  Furthermore, in the above-described embodiment, the case where liquid fuel is supplied from the liquid fuel tank 38 to the liquid fuel supply source pipe 36 and the liquid fuel supply pipe 22 at room temperature has been described. However, the present invention is not limited to this. For liquid fuels that have high viscosity at room temperature such as those that are difficult to atomize, preheat to, for example, 130 ° C. to 150 ° C. using steam or the like to reduce the viscosity and supply the liquid fuel to the liquid fuel supply pipe 22 Thus, it can be easily atomized by the spray mechanism 23 and injected as the liquid fuel mist 29.

  The technique of the present invention is useful as a technique for producing sintered ore used as a raw material for iron making, particularly as a blast furnace, but can also be used as another ore agglomeration technique.

DESCRIPTION OF SYMBOLS 1 ... Raw material hopper 2 ... Drum mixer 3 ... Rotary kiln 4 ... Surge hopper 5 ... Floor hopper 6 ... Drum feeder 7 ... Cutting chute 8 ... Sinter pallet 9 ... Charging layer 10 ... Ignition furnace 11 ... Wind box 15 ... Liquid fuel Injection device 16 ... hood,
DESCRIPTION OF SYMBOLS 21 ... Compressed air supply piping 22 ... Liquid fuel supply piping 23 ... Spray mechanism 24 ... Vertical piping 25 ... Mixing part 26 ... Connection piping 27 ... Branch injection part 28a, 28b ... Injection nozzle part 29 ... Liquid fuel mist 31 ... Compressed gas supply Original pipe 32 ... compressed gas supply source 33 ... storage tank 34 ... compressor 35 ... receiver tank 36 ... liquid fuel supply source pipe 37 ... fuel supply pump 38 ... liquid fuel storage tank 40 ... hot air supply device 41 ... heater 42 ... temperature Control device 43 ... temperature sensor 51 ... baffle plate 52 ... baffle plate row

Claims (10)

A circulating pallet,
A raw material supply device for charging a sintered raw material containing fine ore and carbonaceous material onto the pallet to form a charging layer;
An ignition furnace for igniting the carbonaceous material in the sintered raw material on the pallet;
A sintering machine for producing a sintered cake by burning a carbonaceous material in the charging layer, and a wind box for sucking air below the pallet,
A liquid fuel injection device disposed on the downstream side of the ignition furnace and injecting a liquid fuel having a boiling point of 150 ° C. or higher and having a boiling point of 100 μm or less above the charging layer;
Provided above the liquid fuel injector, it is injected from the liquid fuel injection device, and supplies the hot air temperature to promote vaporization to the liquid fuel of less aspirated particle size 100μm to in the sintering bed A sintering machine comprising a hot air supply device.   The liquid fuel injection device comprises a compressed gas supply source, a liquid fuel supply source, a compressed gas from the compressed gas supply source and a liquid fuel from the liquid fuel supply source, and is atomized to mix the charge layer. The sintering machine according to claim 1, further comprising: a spray mechanism that injects in a horizontal direction.   3. The sintering machine according to claim 1, wherein the temperature of the hot air is set in a temperature range between the flash point of the liquid fuel and the ignition point.   The sintering machine according to claim 1 or 2, wherein the temperature of the hot air is set to a temperature at which a residual oil ratio of the liquid fuel remaining on the surface of the sintered cake is suppressed to 2% or less. .   3. The sintering machine according to claim 1, wherein the temperature of the hot air is set to a temperature in a range of 88 ° C. or more and 200 ° C. or less.   The liquid fuel is characterized in that at least one of petroleum liquid fuel, alcohol liquid fuel, ether liquid fuel, and other hydrocarbon compounds liquid fuel that is in a liquid state near normal temperature is used. Item 6. The sintering machine according to any one of Items 1 to 5.   The sintering machine according to claim 6, wherein the liquid fuel is heavy oil. A sintered raw material containing fine ore and carbonaceous material is charged onto a circulating pallet by a raw material supply device to form a charging layer, transported to an ignition furnace, and the carbonaceous material in the charging layer is ignited. In addition, a method for producing sintered ore in which air is sucked by a wind box disposed below the pallet,
The liquid fuel having a boiling point of 150 ° C. or higher is atomized to a particle size of 100 μm or less by the liquid fuel injection device on the upstream side of the charging layer on the downstream side of the ignition furnace, and the liquid is injected with the hot air supply device. injected from the fuel injection device, and method for producing a sintered ore and supplying the hot air temperature to promote vaporization to the sintering bed the liquid fuel of less aspirated particle size 100μm to within.   The method for producing sintered ore according to claim 8, wherein the liquid fuel is heavy oil.   The method for producing a sintered ore according to claim 8 or 9, wherein the temperature of the hot air is set to a temperature at which the residual oil ratio of the liquid fuel remaining on the cake surface is suppressed to 2% or less.