JP2003105450A - Method and apparatus for cooling reduced-iron agglomerate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently manufacture reduced-iron agglomerates and also to minimize energy required in the melting of the agglomerates in an electric furnace, or the like. SOLUTION: In this method for cooling the reduced-iron agglomerates, a plurality of spray nozzles 1 are arranged above a conveyor 6 provided to a discharge hole 8 of a reduced-iron agglomerate manufacturing facility in such a way that spray water is intermittently spouted through the respective spray nozzles to intermittently cool the agglomerates on the conveyor, and the spray water is spouted so that the relation between spray-water spouting time T1 and stopping time T2 satisfies 1.2×T1<=T1+T2<=10×T1. Accordingly, the agglomerates can be cooled without stopping by intermittent cooling, and atmosphere reoxidation can be suppressed. Further, water content can be regulated to low values, and as a result, the possibility of steam explosion occurring when the agglomerates are put into molten metal can be eliminated.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a facility for producing a reduced iron agglomerate from an iron oxide agglomerate, which cools a high-temperature reduced iron agglomerate which is reduced and continuously discharged in a reducing furnace. To a method and a device therefor.

[0002]

2. Description of the Related Art Conventionally, as a method for cooling reduced iron agglomerates discharged from a reduced iron manufacturing facility, after the reduced iron agglomerates are submerged and cooled in a water tank, they are pulled up by a conveyor from the water tank, The method of directly delivering to an electric furnace after being piled up and stored in piles, then appropriately conveyed and put into an electric furnace has been realized.

However, since the reduced iron agglomerate obtained by this immersion cooling method has a high water content, there is a risk of vapor explosion if it is directly added to the molten metal, so it is limited to the addition to an electric furnace. In addition, there have been problems such as pulverization of reduced iron agglomerates and reduction of metallization rate.

Further, in Japanese Patent No. 3145834, reduced iron obtained by the direct reduction iron making method is molded by a briquette machine facility, and the reduced iron briquette in this state is sprayed with water at 150 ° C./min to 250 ° C./min. Disclosed is a method for producing a reduced iron briquette which is gradually cooled at a cooling rate of.

However, this method is a method of gradually cooling by spray cooling in order to suppress cracking of a high-temperature reduced iron briquette, and cooling of reduced iron agglomerates discharged from a reduced iron manufacturing facility such as a rotary hearth furnace. In addition, the proper water content of the reduced iron agglomerate is not considered.

[0006] Further, in Japanese Patent No. 30096661, the average cooling rate of the high-temperature reduced iron briquette after heat reduction is 1500 ° C / min to 500 ° C / min while the surface temperature is lowered from 650 ° C to 150 ° C. A method of water cooling so as to be in the interval is disclosed.

However, this method relates to the cooling of reduced iron pellets, and its size and properties are different from those of agglomerates such as briquettes targeted by the present invention, and this method cannot be applied as it is. Further, 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 or the cooling rate up to 650 ° C. There is no description of cooling means, and no attention is paid to the water content of the agglomerates.

[0008]

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, and provides a cooling method and apparatus for adjusting the central temperature and water content of reduced iron agglomerates to appropriate ranges. As a subject, a means for solving the following specific technical subject is provided. The reduced iron agglomerates of about 1000 ° C discharged from the reduced iron manufacturing equipment such as the rotary hearth furnace are promptly heated to 300 ° C.
By cooling to below, reoxidation by the atmosphere is suppressed.
By setting the water content of the reduced iron agglomerate after cooling to 6% or less, the reduced iron agglomerate can be charged into the molten metal, and the water evaporation energy at the time of melting can be reduced. By optimizing the cooling time, it is possible to suppress the pulverization of the reduced iron agglomerate and the decrease in the metallization rate.

[0009]

The present invention for solving the above-mentioned problems has the following structures. (1) In a method of cooling a reduced iron agglomerate that reduces an iron oxide agglomerate in a reducing furnace and discharges the reduced iron agglomerate, a high-temperature reduced iron agglomerate is provided at an outlet of the reduced iron production facility. Arrange a conveyor to convey, arrange a plurality of spray nozzles above the conveyor, intermittently cool the reduced iron agglomerate on the conveyor by ejecting spray water intermittently from the spray nozzle, Time T1 to eject the spray water
The method for cooling a reduced iron agglomerate is characterized in that spray water is jetted so that the relationship between the stop time T2 and the stop time T2 is within the range of the following formula (1). 1.2 x T1 ≤ T1 + T2 ≤ 10 x T1 (1)

(2) In an apparatus for cooling a reduced iron agglomerate, which reduces an iron oxide agglomerate in a reduction furnace and discharges it as a reduced iron agglomerate, high-temperature reduced iron at the outlet of the reduced iron production facility. A conveyor that conveys agglomerates is arranged, a plurality of spray nozzles are arranged above the conveyor, and spray water is intermittently ejected from the spray nozzles to intermittently reduce the reduced iron agglomerates on the conveyor. A cooling device for a reduced iron agglomerate, characterized in that the spray nozzles are arranged such that the width B of the spray nozzle in the transport direction and the nozzle pitch P in the transport direction are expressed by the following formula (2). . B ≦ P (2) (3) In the spray nozzle, the relationship between the spread width B of the spray water in the transport direction and the spread width W of the conveyor width is within the range of the following formula (3). The cooling device for the reduced iron agglomerate according to (2). W ≧ 2 × B (3) (4) The relation between the spread width W of the spray water in the conveyor width direction and the conveyor width CW is set within the range of the following expression (4), (2) Or the cooling device of the reduced iron agglomerate according to 3. CW ≦ W (4)

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The device of the present invention will be described with reference to the example of FIG. The iron oxide agglomerate is reduced in the rotary hearth furnace 13 as a reduction furnace, and is continuously discharged from the reduced iron agglomerate discharge port 8. The discharged high temperature reduced iron agglomerate 5 is cooled by water spray from a plurality of spray nozzles 1 while being conveyed on the conveyor 6 in the cooling device 16 connected to the discharge port 8, and reduced iron agglomerate is formed. The compound is discharged from the discharge port 7 and conveyed to a storage device (not shown) or the like.

Each of the spray nozzles 1 is attached to a nozzle header 2 provided above the conveyor 6 in parallel with the conveying direction of the conveyor 6 with a predetermined space. 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 on the tip side of the casing 15. A sludge discharge port 9 for discharging sludge generated by sprinkling water on the reduced iron agglomerate 5 is provided on the rear end side.

FIG. 2 shows an A- line of FIG. 1 on the conveyor 6.
An example of the plane viewed from the arrow A is shown, and the pitch P of the spray nozzles 1 is arranged so that P = B, and the spray water from each spray nozzle 1 has a spreading width B in the transport direction as shown by the spray range 1a. Watered. With this arrangement, the spread widths B of the adjacent nozzles 1 in the transport direction of the spray water do not overlap.

FIG. 3 is an enlarged cross-sectional view taken along the line CC in FIG. 2, in which the spray nozzles 1 are mounted on the spray header 2 at intervals P in the carrying direction, and the spray water spreads on the conveyor 6 in the carrying direction B. Is sprinkled with.

FIG. 4 shows a front view taken along the line BB of FIG. 2, in which the spray nozzle 1 is provided in the spray header 2 which is arranged at the center of the width direction of the conveyor 6, and the spray water is supplied to the conveyor 6.
Water is sprinkled on the upper side with a width W that is wider than the width CW of the conveyor 6 in the width direction. Water is supplied to the spray header 2 through a water supply pipe 3 as illustrated in FIG.

According to the present invention, a plurality of spray nozzles 1 are thus arranged above the conveyor 6 at predetermined intervals in the conveying direction of the reduced iron agglomerate 5, and the spray ejection time T1 at each spray nozzle 1 is set. And the stop time T2 is 1.
The setting is made within the range of 2.times.T1 .ltoreq.T1 + T2 .ltoreq.10.times.T1, and the reduced iron agglomerate 5 on the conveyor is cooled intermittently (on-off) as shown in FIG.

By intermittently cooling, the conveyor 6
The surface temperature of the upper reduced iron agglomerate 5 drops while changing as shown in FIG. 10, for example. That is, when sprayed from the spray nozzle 1 for T1 time and stopped for T time, the surface temperature rises due to the internal heat of the reduced iron agglomerate (recovery heat) during the stop time of T2 after cooling by the spray water for T1 time. ), The temperature rise stops when the temperature inside and outside the reduced iron agglomerate is balanced.

Then, the cooling is started from the temperature balanced by the next spray water. By repeating this,
The cooling pattern is as shown in 0 and the reduced iron agglomerate 5
Is cooled to 100-300 ° C. The temperature of the reduced iron agglomerate 5 drops due to heat exchange in the agglomerate and forced cooling with external spray water, so that intermittent cooling can reduce the water amount density as compared with continuous forced cooling. .
This is because the internal transfer of heat in the reduced iron agglomerate is faster than that in the case where spray water is unilaterally sprinkled from the outside, and thus cooling can be performed with a small water amount density.

Further, the reduced iron agglomerates are formed by the intermittent cooling.
Due to the rise of the surface temperature between cooling and subsequent cooling, the spray water sprinkled on the surface evaporates and the surface dries. By repeating this pattern, on the surface of the reduced iron agglomerate,
It is cooled to the discharge target temperature while repeating watering and evaporation. Thereby, the reduced iron agglomerate 5 discharged from the cooling device of the present invention can secure a water content of 6% or less. The water content of the reduced iron agglomerate is preferably low in order to suppress energy consumption during melting in 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.

Generally, the cooling nozzle is shown in FIG. 11 and FIG.
A conical spray nozzle is used as shown in Fig. 4, and the spread of spray water ejected from the cooling nozzle over the entire width direction and conveyance direction of the reduced iron agglomerate is arranged so as to interfere with each other. Water is sprinkled on the reduced iron agglomerate.

In this state, the temperature difference between the inside and the surface of the reduced iron agglomerate increases due to continuous water sprinkling (high temperature inside, low temperature surface), and it is necessary to increase the amount of water as compared with the intermittent water cooling of the present invention. Occurs. When the amount of water is increased to sufficiently cool the inside, water 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. 11 and 12 are used, the spray ranges 1b and 1c of the nozzles are overlapped with each other, the cooling state varies in the width direction of the conveyor, and the temperature of the agglomerate, The water content varies.

In the first aspect of the present invention, the relationship between the time T1 for jetting the spray water and the time T2 for stopping the spray water is 1.2 × T1.
The setting was made so that ≤T1 + T2 ≤10 x T1. That is, 1.2.times.T1 .ltoreq.T1 + T2 is the minimum time for surely setting the spray water jetting time and the stopping time, and is defined as the condition for surely performing the intermittent cooling. T1 + T
2 ≦ 10 × T1 was set as a condition for effective cooling because the temperature rise due to the internal heat of the reduced iron agglomerate after cooling was not saturated.

Next, according to the second aspect of the present invention, the spread width B of the spray water in the transport direction and the pitch P of the spray nozzles in the transport direction.
Was defined as B ≦ P. This condition allows uniform cooling by determining the pitch of the spray nozzles so that the spread widths B ejected from the spray nozzles 1 do not overlap each other.

In the third aspect of the present invention, the relationship between the spread width W of the spray water in the conveyor width direction and the spread width B of the transport direction is 2
B ≦ W. This condition is that the spray range 1a becomes flat as shown in FIG. 2, and by adopting a flat spray nozzle, for example, since the spread width B of the spray water in the transport direction is almost constant in the conveyor width direction, Variations in the cooling state are small, and intermittent cooling can be effectively performed.

In the second aspect of the invention, the relationship between the spread width W of the spray water in the conveyor width direction and the conveyor width CW is set within the range of CW≤W, that is, W and CW.
5, the cooling capacity α shown in FIG. 5 is obtained on the conveyor, and the reduced iron agglomerates on the conveyor 6 are uniformly cooled in the width direction of the conveyor.

Next, an embodiment is shown in FIGS. In the intermittent cooling of the example of the present invention, the relation between the spread width B of the spray water in the conveying direction and the arrangement pitch P of the spray nozzles is B ≦ P, and the relation between the sprinkling time and the stop time is 1.2 × T1 ≦ T1 + T2. The continuous cooling of the comparative example is B ≧ P. FIG. 6 shows the relationship between the central temperature and the amount of sprinkling water during cooling of the reduced iron agglomerate, and it can be seen that the intermittent cooling of the present invention example is superior to the continuous cooling of the comparative example. According to the present invention, the central temperature of the reduced iron agglomerate may be cooled to preferably 300 ° C. or lower indicated by the solid line, and more preferably 200 ° C. or lower indicated by the broken line. In the intermittent cooling, the sprinkling amount ratio is 0.7 or more and is 300 ° C or less,
In continuous cooling, it was necessary to set the water spray amount ratio to 2.0.

FIG. 7 shows the relationship between the amount of water sprayed and the water content after cooling. In the example of the present invention, the water content of the reduced iron agglomerate can be adjusted by the water sprinkling amount. The water content is preferably 6% or less shown by the solid line, and more preferably 5% or less shown by the broken line. In intermittent cooling, the water content ratio is 1.3 or less and the water content is 6% or less, and when the water spray 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 temperature 300
The water content was more than 6% at the sprinkling amount ratio satisfying the conditions below ℃.

FIG. 8 is a summary of FIG. 6 and FIG. 7, showing the relationship between the central temperature and the water content of the reduced iron agglomerates. In the continuous cooling of the comparative example, when the central 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 central temperature shown by the solid line is 300 ° C.
Hereinafter, the water content can be adjusted to 6% or less, and a good reduced iron agglomerate can be obtained.

[0030]

As described above, according to the method and apparatus of the present invention, high-temperature reduced iron agglomerates are intermittently cooled so that the agglomerates can be rapidly improved.
It can be efficiently cooled to 00 to 300 ° C., and reoxidation due to the atmosphere can be suppressed. Further, the water content of the cooled reduced iron agglomerate can be adjusted to a low level, the fear 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 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 C-C of FIG. 2, showing an example of spray watering in the present invention.

FIG. 4 is a front view taken along the line BB of FIG. 2, showing an example of the present invention.

5 is an explanatory diagram showing a cooling capacity in the example of FIG.

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 an agglomerate in the present invention.

FIG. 10 is a graph showing an example of temperature change of an agglomerate in the present invention.

FIG. 11 is an explanatory diagram showing an arrangement example of a conventional spray nozzle.

FIG. 12 is an explanatory diagram showing another example of arrangement of conventional spray nozzles.

[Explanation of symbols]

1: Spray nozzle 1a: Spray range with flat spray nozzle 1b: Spray range with conical spray nozzle 2: Nozzle header 3: Water supply pipe 4: Steam exhaust port 5: Reduced iron agglomerate 6: Conveyor 7,8: Reduced iron ingot Product discharge outlets 9 and 10: Sludge outlet 11: Sludge tank 12: Sludge conveyor 13: Rotary hearth furnace 14: Sludge recovery tank 15: Casing 16: Cooling device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukio Owaki             46-59 Nakahara, Tobata-ku, Kitakyushu City Made in Japan             Engineering Co., Ltd. F-term (reference) 4K001 AA10 BA02 CA23 CA24 GA11                       GB11                 4K063 AA07 BA02 CA01 CA06 EA00                       EA10

Claims (4)

[Claims] 1. A method of cooling a reduced iron agglomerate for reducing iron oxide agglomerates in a reduction furnace and discharging the reduced iron agglomerates as a reduced iron agglomerate. A conveyor that conveys the compound is arranged, and a plurality of spray nozzles are arranged above the conveyor, and spray water is intermittently ejected from the spray nozzle to intermittently cool the reduced iron agglomerate on the conveyor. Then, the method for cooling a reduced iron agglomerate is characterized in that the spray water is jetted so that the relation between the time T1 for jetting the spray water and the time T2 for stopping the jet is within the range of the following formula (1). 1.2 x T1 ≤ T1 + T2 ≤ 10 x T1 (1) 2. An apparatus for cooling a reduced iron agglomerate for reducing an iron oxide agglomerate in a reduction furnace and discharging the reduced iron agglomerate as a reduced iron agglomerate, wherein a high temperature reduced iron agglomerate is provided at an outlet of the reduced iron production facility. A conveyor that conveys the compound is arranged, and a plurality of spray nozzles are arranged above the conveyor, and spray water is intermittently ejected from the spray nozzle to intermittently cool the reduced iron agglomerate on the conveyor. An apparatus for cooling a reduced iron agglomerate, characterized in that the spray nozzles are arranged such that the width B of the spray nozzle in the carrying direction and the nozzle pitch P of the carrying direction are expressed by the following formula (2). B ≦ P (2) 3. The reduced iron according to claim 2, wherein the spray nozzle has a relationship between the spread width B of the spray water in the conveying direction and the spread width W of the conveyor in the range of the following formula (3). Agglomerate cooling device. W ≧ 2 × B ・ ・ (3) 4. The reduced iron agglomerate according to claim 2 or 3, wherein the relationship between the spread width W of the spray water in the conveyor width direction and the conveyor width CW is set within the range of the following formula (4). Cooling system. CW ≦ W (4)