JP4027744B2 - Cooling device for reduced iron agglomerates - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for cooling a high-temperature reduced iron agglomerate that is reduced in a reduction furnace and continuously discharged in an facility for producing a reduced iron agglomerate from an iron oxide agglomerate. .
[0002]
[Prior art]
As a cooling method for reduced iron agglomerates discharged from the reduced iron production facility, conventionally, after the reduced iron agglomerates are submerged and cooled in the water tank, they are pulled up from the water tank by a conveyor, and then directly discharged into the soil to pile up the piles. After being stored, a method of carrying it appropriately and putting it into an electric furnace has been put into practice.
[0003]
However, in this submerged cooling method, the water content of the reduced iron agglomerate is high, and there is a risk of causing a steam explosion when thrown into the molten metal. There has also been a problem of powdering the agglomerated material and lowering the metalization rate.
[0004]
In Japanese Patent No. 314534, reduced iron obtained by a direct reduction iron making method is formed by briquette machine equipment, and the reduced iron briquette in this state is cooled at 150 ° C./min to 250 ° C./min with spray water. Discloses a method for producing reduced iron briquettes that are cooled slowly.
[0005]
However, this method is a method of slow cooling by spray cooling to suppress cracking of high-temperature reduced iron briquettes, and a method of cooling reduced iron agglomerates discharged from reduced iron production facilities such as a rotary hearth furnace In addition, the proper moisture content of the reduced iron agglomerates is not considered.
[0006]
Further, in Japanese Patent No. 3009661, the average cooling rate during the temperature reduction of the high-temperature reduced iron pellets after heat reduction from 650 ° C. to 150 ° C. is between 1500 ° C./min and 500 ° C./min. A method of water cooling is disclosed.
[0007]
However, this method relates to cooling of reduced iron pellets, and is different in size and property from the agglomerates such as briquettes targeted by the present invention, and this method cannot be applied as it is. The temperature of the reduced iron agglomerate discharged from the rotary hearth furnace is about 1000 ° C., but there is no description about the cooling method and cooling rate up to 650 ° C., and the specific temperature is also below 650 ° C. There is no description of the cooling means, and no attention is paid to the water content of the agglomerated material.
[0008]
[Problems to be solved by the invention]
The present invention solves the problems of the prior art as described above, and solves the following specific technical problems with the object of providing a cooling device that makes the center temperature and moisture content of the reduced iron agglomerates within an appropriate range. Provide a means.
Reoxidation by the atmosphere is suppressed by rapidly cooling a reduced iron agglomerate at about 1000 ° C. discharged from reduced iron production equipment such as a rotary hearth furnace to 300 ° C. or less. By setting the water content of the reduced iron agglomerated product after cooling to 6% or less, the reduced iron agglomerated product can be introduced into the molten metal, and the water evaporation energy at the time of melting is reduced. By optimizing the cooling time, pulverization of the reduced iron agglomerate and reduction in the metalization rate are suppressed.
[0009]
[Means for Solving the Problems]
The first invention apparatus of the present invention for solving the above problems is a reduced iron agglomerate production facility that reduces iron oxide agglomerates in a reduction furnace and discharges them as reduced iron agglomerates. A device for cooling the reduced iron agglomerate, comprising a conveyor for conveying the reduced iron agglomerated material at a discharge port of the reduced iron agglomerate production facility, above or above the conveyor and A plurality of spray nozzles are provided below, and spray water is continuously ejected from each of the spray nozzles so as to intermittently cool the reduced iron agglomerate on the conveyor, with an interval in the conveying direction of the reduced iron agglomerate. The reduced iron agglomerate cooling apparatus is characterized in that the relationship between the spread width B of the spray water sprayed in the transport direction and the spray nozzle pitch P is in the range of the following formula (1): It is.
1.2 × B ≦ P ≦ 10 × B (1)
[0010]
Further, the second invention apparatus of the present invention for solving the above-mentioned problems is a reduced iron agglomerate production facility that reduces iron oxide agglomerates in a reduction furnace and discharges them as reduced iron agglomerates. Is a device for cooling the reduced iron agglomerate, comprising a conveyor for conveying the reduced iron agglomerated material at a discharge port of the reduced iron agglomerate production facility, above or above the conveyor And a plurality of spray nozzles below, and in order to intermittently cool the reduced iron agglomerate on the conveyor by spraying spray water continuously from each of the spray nozzles, the interval in the conveying direction of the reduced iron agglomerate is increased. The reduced iron agglomerate cooling apparatus, characterized in that the relationship between the spreading width B in the conveying direction of the spray water sprayed and the spreading width W in the conveyor width is in the range of the following formula (2): It is.
W ≧ 2 × B (2)
[0011]
And in the said 1st invention apparatus and 2nd invention apparatus, it is preferable to make the relationship of the conveyor width direction breadth W and the conveyor width | variety CW of the said spray water into the range of following (3) Formula.
CW ≦ W (3)
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The apparatus of the present invention will be described with reference to the example of FIG. The iron oxide agglomerate is reduced in a rotary hearth furnace 13 as a reduction furnace and continuously discharged from the reduced iron agglomerate discharge port 8. The discharged reduced iron agglomerated material 5 is cooled on the conveyor 6 in the cooling device 16 connected to the discharge port 8 and cooled by water sprayed from the plurality of spray nozzles 1 to be reduced iron agglomerated. It is discharged from the chemical discharge port 7 and conveyed to a storage device (not shown).
[0013]
Each spray nozzle 1 is attached to the nozzle header 2 provided above the conveyor 6 in parallel with the conveying direction of the conveyor 6 at a predetermined interval.
The spray nozzle 1, the spray header 2, and the conveyor 6 are covered with a casing 15, and a reduced iron agglomerate discharge port 7 for discharging the cooled reduced iron agglomerate 5 is provided at the front end side of the casing 15. Provided on the rear end side is a sludge discharge port 9 for discharging sludge generated by watering the reduced iron agglomerate 5.
[0014]
FIG. 2 shows an example of the AA arrow plane of FIG. 1 on the conveyor 6, and the spray water from each spray nozzle 1 is spaced in the conveying direction spread width B as shown by the spray range 1-1. It is sprinkled with water.
FIG. 3 is an enlarged cross-sectional view taken along the line CC in FIG. 2. Each spray nozzle 1 is attached to the spray header 2 with a spacing P in the transport direction, and spray water is spread on the conveyor 6 in the transport direction with a width B. It is sprinkled with water.
[0015]
4 shows a front view taken along the line B-B in FIG. 2, the spray nozzle 1 is provided on the spray header 2 disposed at the center in the width direction of the conveyor 6, and the spray water is not less than the width CW of the conveyor 6 on the conveyor 6. Water is sprayed with a width W of the width direction.
Water is supplied to the spray header 2 from a water supply pipe 3 as illustrated in FIG.
[0016]
The apparatus of the present invention thus arranges the plurality of spray nozzles 1 above the conveyor 6 at intervals in the conveying direction of the reduced iron agglomerate 5, and continuously sprays spray water from each spray nozzle. In this way, the reduced iron agglomerate 5 on the conveyor 6 is intermittently cooled. The condition for intermittent cooling is B <P as can be seen from FIG.
[0017]
By cooling intermittently, the surface temperature of the reduced iron agglomerate 5 on the conveyor 6 drops while changing as shown in FIG. 10, for example. That is, after being cooled by the spray water sprayed from the first spray nozzle 1, the temperature starts to rise due to the internal heat of the reduced iron agglomerate until it is cooled by the next spray water. The temperature rise stops when the temperature inside and outside of the room is balanced.
[0018]
And cooling is started from the temperature balanced by the next spray water. By repeating this, the reduced iron agglomerate 5 is cooled to 100 to 300 ° C. in a cooling pattern as shown in FIG. Since the reduced iron agglomerate 5 drops in temperature due to the transfer of heat in the agglomerate and forced cooling by external spray water, intermittent cooling can reduce the water density compared to continuous forced cooling. . This is presumably because the internal movement of heat in the reduced iron agglomerated material is faster than when spraying spray water from the outside, so that it can be cooled with a small water density.
[0019]
Further, the reduced iron agglomerate is intermittently cooled, and the spray water sprayed on the surface evaporates and the surface is dried due to the increase in the surface temperature between the cooling and the subsequent cooling. By repeating this pattern, the surface of the reduced iron agglomerate is cooled to the discharge target temperature while watering and evaporation are repeated. Thereby, the reduced iron agglomerate 5 discharged from the cooling device of the present invention can ensure a moisture content of 6% or less.
The water content of the reduced iron agglomerated material is preferably low in order to suppress energy consumption during melting by an electric furnace or the like, and is preferably 6% or less in order to prevent steam explosion at the time of charging into the molten metal.
[0020]
The discharge temperature of the reduced iron agglomerate after cooling by the apparatus of the present invention may be 100 to 300 ° C. The reduced iron agglomerates at about 1000 ° C. discharged from the rotary hearth furnace are cooled to 100 to 300 ° C. by intermittent watering.
In general, as shown in FIGS. 14 and 15, the cooling nozzles are arranged such that conical spray nozzles are sprayed uniformly over the entire width direction and the conveying direction of the reduced iron agglomerate.
[0021]
In this state, the temperature difference between the inside and the surface of the reduced iron agglomerate is increased by continuous watering (the inside is at a high temperature and the surface is at a low temperature), and it is necessary to increase the amount of water compared to the intermittent water cooling of the present invention. When the amount of water is increased in order to sufficiently cool the inside, moisture remains on the surface that has already become low temperature, and the water content exceeds 6%.
Further, when the conical spray nozzles as shown in FIGS. 14 and 15 are used, the spray ranges 1-2 and 1-3 of each nozzle are overlapped, the cooling state varies in the conveyor width direction, and the temperature of the agglomerated product is increased. Variation in moisture occurs.
[0022]
In the first invention apparatus of the present invention, the relationship between the spread width B of the spray water in the transport direction and the arrangement pitch P of the spray nozzles is set in the range of the formula (1).
1.2 × B ≦ P is determined as a condition for reliably separating the spray range 1-1 between adjacent spray nozzles 1 as shown in FIG. 2, that is, a condition for performing reliable intermittent cooling. .
P ≦ 10 × B was determined as a condition for effective cooling without saturating the temperature rise due to internal heat of the reduced iron agglomerate between cooling and the next cooling.
[0023]
Next, the 2nd invention apparatus of this invention made the relationship of the conveyance direction spreading width B and the conveyor width direction spreading width W of the spray water the range of said (2) Formula. This condition is that the spray range 1-1 is flat as shown in FIG. 2, for example, by adopting a flat spray nozzle, the spread width B of the spray water in the conveying direction is substantially constant in the conveyor width direction. Since the variation in the cooling state is small, intermittent cooling can be performed effectively.
[0024]
In the first and second invention devices, the relationship between the spread width W of the spray water in the width direction of the conveyor and the conveyor width CW is within the range of the expression (3), that is, the relationship between W and CW is illustrated. By doing so, the reduced iron agglomerate on the conveyor 6 is uniformly cooled in the conveyor width direction.
[0025]
In FIG. 1, the reduced iron agglomerate 5 discharged from the rotary hearth furnace 13 is continuously placed on a conveyor 6 and conveyed. Above the conveyor 6, the spray nozzle 1 is arranged at a predetermined interval in the conveying direction of the conveyor 6. For this reason, although spray water is sprinkled continuously from each spray nozzle 1, the water spray to the reduced iron agglomerate 5 continuously conveyed on the conveyor 6 turns into intermittent water spray. The cooling pattern of intermittent water spray seen from the agglomerate is as shown in FIG. 9, for example, and the ON and OFF times of water spray can be adjusted by the relationship between P and B.
[0026]
Next, examples are shown in FIGS. In the intermittent cooling of the example of the present invention, the relationship between the spread width B of the spray water in the transport direction and the arrangement pitch P of the spray nozzle is 2B = P, and the continuous cooling of the comparative example is B ≧ P.
FIG. 6 shows the relationship between the central temperature during cooling of the reduced iron agglomerate and the amount of sprinkling. It can be seen that the intermittent cooling of the example of the present invention is superior in cooling effect to the continuous cooling of the comparative example. With the apparatus of the present invention, the center temperature of the reduced iron agglomerate is preferably cooled to 300 ° C. or lower, more preferably 200 ° C. or lower, indicated by a broken line. In the intermittent cooling, the water spray ratio is 0.7 to 300 ° C., whereas in the continuous cooling, the water spray ratio needs to be 2.0.
[0027]
FIG. 7 shows the relationship between the water spray amount and the water content after cooling. In the present invention example, the water content of the reduced iron agglomerate can be adjusted by the amount of water spray. The moisture content is preferably 6% or less indicated by a solid line, and more preferably 5% or less indicated by a broken line. In intermittent cooling, the water content is 1.3% or less and the water content is 6% or less. The water ratio is 0.7 or more and 1.3 or less, the temperature is 300 ° C. or less and the water content is 6% or less. Then, the water content was more than 6% at the water spray ratio that satisfied the temperature of 300 ° C. or lower.
[0028]
FIG. 8 is a summary of FIG. 6 and FIG. 7 and shows the relationship between the center temperature of the reduced iron agglomerate and the moisture content. In the continuous cooling of the comparative example, when the center temperature of the reduced iron agglomerate is 300 ° C. or less, the water content exceeds 6%, and when the water content is 6% or less, the center temperature exceeds 300 ° C. On the other hand, in the intermittent cooling of the example of the present invention, the center temperature shown by a solid line can be adjusted to 300 ° C. or less and the water content can be adjusted to 6% or less, and a good reduced iron agglomerate can be obtained.
[0029]
FIG. 11 shows another example of the present invention. That is, the high-temperature reduced agglomerated product 5 reduced by the rotary hearth furnace 13 is sent from the discharge port 8 onto the conveyor 6 in the cooling device 16 connected to the discharge port, and is conveyed while being conveyed. It is cooled by water sprayed from a plurality of upper spray nozzles 1 and lower spray nozzles 1 a disposed above and below and discharged from the reduced iron agglomerate discharge port 7. The reduced agglomerated product is cooled from above and below by the plurality of nozzles 1, 1 a in which the high-temperature reduced agglomerated material placed on the conveyor 6 is arranged above and below the conveyor 6. Thereby, the reduced agglomerated material can be placed on the conveyor 6 in a plurality of layers, and productivity is improved. FIG. 12 shows the condition of water spraying from the spray nozzles 1 and 1a arranged above and below the conveyor 6 as in FIG. 4, and FIG. 13 shows water supply means 2 and 2a for supplying water to the upper and lower spray nozzles 1 and 1a as in FIG. 3, 3a are shown.
[0030]
The conveyor 6 employs a plate-like shape and a wire mesh shape. However, when cooling the reduced agglomerates having nozzles disposed above and below the conveyor 6, the cooling effect is further improved by employing the wire mesh conveyor 6. To do. Further, the opening size of the wire mesh may be any size as long as it does not drop when the reduced agglomerated material is placed, but it is desirable that the opening size is about 10 mm.
[0031]
【The invention's effect】
As described above, according to the apparatus of the present invention, high-temperature reduced iron agglomerates can be efficiently cooled to 100 to 300 ° C. at a stretch by intermittent cooling, and reoxidation by the atmosphere can be suppressed. In addition, the water content of the cooled reduced iron agglomerate can be adjusted to be low, the risk of steam explosion at the time of charging into the molten metal is eliminated, and the energy required for melting can be minimized.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing an example of the present invention.
FIG. 2 is a plan view taken along the line AA of FIG. 1, showing an example of the present invention.
FIG. 3 is an enlarged cross-sectional view taken along the line CC of FIG. 2, showing an example of spray watering according to the present invention.
4 shows an example of the present invention and is a front view taken along arrow BB in FIG.
FIG. 5 is an explanatory view showing an example of a spray nozzle in the present invention.
FIG. 6 is a graph showing an example of the present invention.
FIG. 7 is another graph showing an example of the present invention.
FIG. 8 is another graph showing an example of the present invention.
FIG. 9 is an explanatory diagram showing an example of a cooling pattern viewed from the agglomerated material according to the present invention. FIG. 10 is a graph showing an example of temperature change of the agglomerated material according to the present invention.
FIG. 11 is an explanatory view of an example in which spray nozzles are arranged vertically on another embodiment of the present invention.
12 is a view showing a watering condition of the example of the present invention shown in FIG. 11. FIG.
13 is a view showing water supply means of the example of the present invention shown in FIG.
FIG. 14 is an explanatory view showing an arrangement example of a conventional spray nozzle.
FIG. 15 is an explanatory view showing another arrangement example of a conventional spray nozzle.
[Explanation of symbols]
1: Spray nozzle 1a: Lower spray nozzle 1-1: Spray range by flat spray nozzle 1-2, 1-3: Spray range by conical spray nozzle 2: Nozzle header 2a: Lower nozzle header 3: Water supply pipe 3a: Lower water supply Pipe 4: Steam exhaust port 5: Reduced iron agglomerate 6: Conveyor 7, 8: Reduced iron agglomerate discharge port 9, 10: Sludge discharge port 11: Sludge tank 12: Sludge conveyor 13: Rotary hearth furnace 14: Sludge recovery tank 15: casing 16: cooling device

Claims (3)

In a reduced iron agglomerate production facility that reduces iron oxide agglomerates in a reduction furnace and discharges them as reduced iron agglomerates, an apparatus for cooling the high-temperature reduced iron agglomerates discharged, A conveyor that conveys high-temperature reduced iron agglomerate is disposed at the discharge port of the reduced iron agglomerate production facility, and a plurality of spray nozzles are continuously provided from the respective spray nozzles above, above and below the conveyor. In order to intermittently cool the reduced iron agglomerate on the conveyor by spraying spray water, the reduced iron agglomerated material is arranged at intervals in the conveying direction of the reduced iron agglomerated material, and the width B in the conveying direction of the spray water to be ejected is arranged. And an arrangement pitch P of spray nozzles within the range of the following formula (1), a cooling apparatus for reduced iron agglomerates.
1.2 × B ≦ P ≦ 10 × B (1) In a reduced iron agglomerate production facility that reduces iron oxide agglomerates in a reduction furnace and discharges them as reduced iron agglomerates, an apparatus for cooling the high-temperature reduced iron agglomerates discharged, A conveyor that conveys high-temperature reduced iron agglomerate is disposed at the discharge port of the reduced iron agglomerate production facility, and a plurality of spray nozzles are continuously provided from the respective spray nozzles above, above and below the conveyor. In order to intermittently cool the reduced iron agglomerate on the conveyor by ejecting spray water, the reduced iron agglomerated material is arranged at intervals in the conveying direction of the reduced iron agglomerated material, and the spread width B of the spray water to be ejected in the conveying direction A reduced iron agglomerate cooling apparatus characterized in that the relationship between the width of the conveyor and the width W of the conveyor is in the range of the following formula (2).
W ≧ 2 × B (2) The reduced iron agglomerate cooling apparatus according to claim 1 or 2, wherein the relationship between the spread width W of the spray water in the conveyor width direction and the conveyor width CW is in the range of the following formula (3).
CW ≦ W (3)

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