JP3458572B2 - Waste tire treatment method and its firing furnace - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste tire treatment method for treating rubber waste such as waste tires using a great kiln type firing furnace in a pellet manufacturing plant for blast furnaces, and a firing furnace therefor.

[0002]

2. Description of the Related Art Conventionally, a pellet manufacturing process in a pellet manufacturing facility for a blast furnace includes a granulating step of molding a finely powdered raw material into small spheres, followed by firing by heating and curing the small spheres in an oxidizing atmosphere. It consists of two steps.

Granulation is carried out by rolling a raw material containing an appropriate amount of water in a granulating machine such as a disk type pelletizer or a drum type pelletizer to form particles in a snowball type, and a certain particle size (usually about 9 mm to 13 mm). To obtain a small sphere. In addition to water, a binder such as bentonite for promoting the granulation effect or slaked lime for adjusting viscosity may be added. The green pellets formed in this way have low strength as they are and cannot be used as a raw material for the blast furnace. Therefore, by further heating them at a high temperature through a firing furnace, the strength necessary for the raw material for the blast furnace is secured. .

That is, in the firing step, the small spheres formed in the granulation step are heated at a high temperature to evaporate the water content of the small spheres, and the fine ores forming the small spheres are metallurgically bonded to each other. The purpose is to provide physical properties that can withstand use in a blast furnace. Of the types of furnaces used in the above-mentioned firing process, a great kiln type firing furnace that is currently widely used will be described.

The great kiln type firing furnace is a combination of a traveling grate 20 and a rotary kiln 24. As shown in FIG. 5, the traveling grate 20 is on the left side and the rotary kiln is located on the right side, that is, the discharge side end of the great kiln. 24 is connected. A circular cooler 25 is provided below the discharge part of the rotary kiln 24 to cool the fired pellets and simultaneously recover heat. The heating of the entire furnace is performed by the kiln burner 26 provided in the discharge part of the rotary kiln 24, and the traveling grate 20 itself is not provided with a burner. Therefore, the heating inside the traveling grate 20 mainly depends on the high temperature gas supplied from the rotary kiln 24.

Inside the traveling grate 20, the drying chamber 20a, the water separating chamber 20b, and
It is divided into three chambers including a preheating chamber 20c, and the internal temperature of each chamber is adjusted to about 230 ° C in the drying chamber 20a and 390 in the water separating chamber 20b by adjusting the temperature such as sucking in cold air (atmosphere). ℃, preheating chamber 20c is 10
The temperature is maintained at 50 to 1150 ° C. A preheating burner 21 is arranged in the preheating chamber 20c to compensate for the lack of heat.

[0007]

However, in the conventional great kiln type firing furnace, when coal is used as the main fuel, about 10% of ash content is contained, and this ash content is vaporized during the combustion of coal. Therefore, there is a problem that it adheres to the inner wall of the rotary kiln 24, the preheating chamber 20c of the traveling grate 20, or both of them.

Further, if a fuel such as a gas having a high burning speed is used for the purpose of solving the problem, the combustion is completed near the kiln burner 26, so that the temperature may be lowered at the inlet of the rotary kiln 24. When the temperature drop occurs in this way, the metallurgical bond between the pellets is impaired,
This will cause the pellets to be pulverized at the inlet of the rotary kiln 24. As a result of the powdered pellets becoming hard to roll in the rotary kiln 24, they adhere to the refractory bricks forming the inner wall of the rotary kiln 24. Further, the adhered matter deteriorates the air permeability inside the rotary kiln 24 and the inlet portion, and causes an adverse effect such as irregular rolling of pellets. In addition, there is a problem that the refractory bricks are peeled off when removing the deposits.

The present invention has been made in consideration of the problems of the conventional great kiln type firing furnace as described above. A part of the firing fuel is discarded as a fuel containing no ash and having a slow burning rate. It is an object of the present invention to provide a waste tire processing method and a firing furnace for the same, which are capable of reducing damage to the inner wall of a great kiln type combustion furnace and preventing pulverization of pellets by replacing the tire crushed pieces. .

[0010]

The present invention relates to a method for treating rubber waste such as waste tires using a great kiln type firing furnace in a pellet manufacturing facility for a blast furnace, and a firing furnace therefor, In order to achieve the above object, an invention is presented in which a crushed piece of rubber waste is introduced into a kiln burner as an auxiliary fuel.

In the method for treating waste tires according to the present invention, waste tires crushed to an average particle size of 5 mm or less and having steel cords removed are used as kiln burners in a great kiln-type firing furnace.
Alternatively, the gist is to introduce it as an auxiliary fuel for firing into a blowing nozzle arranged in parallel with the kiln burner and burn it with a burner flame. The firing furnace for that purpose has an average particle size of 5 mm.
The gist of the present invention is to provide a crushed piece blowing means for introducing a waste tire crushed and having steel cord removed into a kiln burner or a blowing nozzle arranged in parallel with the kiln burner as auxiliary fuel for firing. The introduction as the auxiliary fuel for firing means, for example, 20% by weight or less with respect to the main fuel introduction amount such as pulverized coal, gas, and heavy oil.

The waste tire in the present invention is a rubber-based waste (used rubber generated from various industrial fields) from which the steel cord has been removed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the drawings. The method for treating a waste tire according to the present invention will be described with reference to FIGS.

FIG. 1 shows the structure of a rotary kiln discharge part of a great kiln type firing furnace applied to a waste tire processing method. In the figure, a hood 2 is attached to a discharge end of a rotary kiln 1, and a hood 2 is provided with a kiln burner (hereinafter abbreviated as burner) 3.

The burner 3 is arranged so as to project into the rotary kiln 1 and is designed to keep the inside of the kiln at about 1300 ° C. Therefore, the pellets in the kiln are heated by radiation from the flame and conduction from the refractory brick heated by the radiation.

The burner 3 includes a main pipe 3a and the main pipe 3 thereof.
It is composed of a branch pipe 3b connected to a, and the pulverized coal as the main fuel is introduced into the main pipe 3a.
In b, waste tire crushed pieces as auxiliary fuel are introduced.
The waste tire crushed pieces to be introduced have an average particle size adjusted to 5 mm or less, and the introduction amount is 2 with respect to the main fuel introduction amount.
It is set to 0% by weight or less.

The particle size adjustment of the above-mentioned waste tire crushed pieces is carried out by the crushing process shown in FIG. That is, the waste tire is crushed to about 100 mm in advance, roughly crushed to about 50 mm, and the metal such as wires is magnetically removed, and further crushed to about 10 mm to remove the long fibers from the chemical fibers contained in the waste tire. And further pulverized to a particle size of 10 mm or less. Hereinafter, each step will be described in detail.

Waste Tire Crushing Process The waste tires 30 are conveyed one by one by the hook conveyor 31 and put into the crusher 32. The crusher 32
It is a biaxial rotary shear type, and is designed to crush a waste tire containing wire cords, that is, a steel radial tire with a tough cutter. A screen having a large number of 100 mm holes is arranged below the crusher 32. The waste tire is repeatedly crushed until it becomes a small piece, and the crushed piece that has passed through the screen is discharged onto the conveyor 33. It is designed to be transferred to the top.

Coarse crushing and magnetic separation process Since the steel wire (bead and cord) and the synthetic fiber are embedded in the rubber inside the crushed piece, a compact 1
They are decomposed while being rubbed by using an axial rotor type coarse crusher 35. The obtained decomposed product is placed on the conveyor 36 for wire removal and returned to the upstream side of the process, that is, the conveyor 34. Then, only the wire is selected by the magnetic separator 37 arranged in the middle of conveyance on the conveyor 34, and the rubber pieces with the wire are further selected by the magnetic separator 38, and the coarse rubber crusher 35 is subjected again. The magnetically selected wire is discharged through the conveyor 39.

Meanwhile during the grinding and chemical fiber sorting step, rubber fragments containing no iron (at this stage 3-1
0 cm) is further finely pulverized by a single-screw rotor type medium pulverizer 40 having the same structure as the above coarse pulverizer. The rubber piece discharged from the medium crusher 40 is a mixture in which synthetic fibers are mixed, and a small amount of wire mixed in the rubber piece is magnetically selected by the magnetic separator 41, and then by the vibrating screener 42. Sieving particles of 8 mm or more, the thick and long synthetic fibers (about 10 to 25 mm) therein are removed by air separation and returned to the intermediate crusher 40 via the belt conveyor 43. It should be noted that long synthetic fibers are collected by the cyclone 44, and dust dust generated from other places is collected by a bag filter and packed in a bag.

Fine pulverization and chemical fiber selection step If tire particles having a particle size of 5 mm or less are used, a fine pulverization step is required. Since the rubber particles obtained from the vibrating sieving machine 42 still contain a considerable amount of short fibers, the specific gravity sorter 45 separates the synthetic fibers from the rubber particles.

Fine particles having a tire particle size of 5 mm or less are sieved and collected by a vibrating sieving machine 46, and the rubber particles remaining on the sieve are applied to a two-roll type fine crushing machine 47. What was crushed by the roll was a vibration conveyor 48 and an air transportation device 49.
It is again passed through the vibrating sieving machine 50 to collect tire particles having a particle size of 5 mm or less, and those remaining on the screen are returned to the fine crushing machine 51. The tire particles obtained in this way are transported to and stored in the product bunker by the pneumatic transportation device 52.

If the waste tire is finely crushed through the above steps, almost 100% of the steel cord can be removed. Then, the waste tire crushed pieces pulverized to a desired particle size of 5 mm or less can be stored in the receiver tank 10.

The waste tire crushed pieces thus obtained are blown from the branch pipe 3b by pneumatic transportation, sent to the kiln burner 3, and burned by the flame. The waste tire crushed piece is a fuel having a much lower ash content than coal and has a slow burning rate, so that it is possible to prevent the internal temperature from decreasing at the inlet of the rotary kiln 1. Therefore, the metallurgical bond between the pellets can be maintained during the firing process, and the pulverization of the pellets can be prevented. Table 1 shown below compares the performance of various fuels introduced into the kiln burner.

[0026]

[Table 1]

As is clear from Table 1, the waste tire has a small amount of ash, is hardly pulverized, and can be pneumatically transported, and therefore, is suitable as an auxiliary fuel to be supplied to the firing furnace. On the other hand, when waste plastic is selected as the auxiliary fuel, the surface layer melts due to frictional heat generated during pneumatic transportation and waste plastic particles adhere to each other or adhere to refractory bricks. It turned out to be unsuitable.

FIG. 4 shows the temperature distribution inside the rotary kiln when the waste tire crushed pieces are supplied to the kiln burner as an auxiliary fuel. When the waste tire crushed pieces which are fuels with a slow burning rate are used, It shows that the temperature distribution can be shifted to the rotary kiln inlet side. Therefore, it is possible to prevent the temperature of the kiln inlet from decreasing.

Further, the structure for burning the waste tire crushed pieces with the kiln burner is not limited to that shown in FIG. 1, but may be configured as shown in FIG. In the configuration of FIG. 2, a nozzle 3c for blowing the waste tire crushed pieces is arranged in parallel with the kiln burner 3 for introducing the main fuel.
It is designed to be blown out toward the flame from the nozzle 3c. Also in such a configuration, the waste tire crushed pieces can be burnt as in the configuration of FIG.

[0035]

As is apparent from the above description,
According to the present invention, a part of the firing fuel supplied to the kiln burner of the great kiln type firing furnace is replaced with a waste tire as a fuel that does not contain ash and has a slow burning rate. Reduce inner wall damage,
Moreover, it is possible to prevent pulverization of the pellets.

Further, according to the present invention, a part of the fuel for burning pellets can be replaced with the crushed pieces of waste tire which cost little, so that the cost can be reduced in the production of pellets for the blast furnace.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a great kiln type firing furnace used in the method for treating waste tires of the present invention.

FIG. 2 is a view, corresponding to FIG. 1, showing another example of the method for blowing crushed pieces of waste tire.

FIG. 3 is a process explanatory diagram showing a waste tire crushing process according to the present invention.

FIG. 4 is a graph showing an internal temperature distribution of the rotary kiln according to the present invention.

FIG. 5 is an explanatory diagram showing a configuration of a conventional great kiln type firing furnace.

[Explanation of symbols]

1 rotary kiln 2 hood 3 kiln burner 3a Main 3b Branch pipe 10 receiver tank

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jiro Yamagata 1 Kanazawa-machi, Kakogawa-shi, Hyogo Prefecture Kobe Steel Works, Ltd. Inside the Kakogawa Steel Works (72) Nobuyuki Iwasaki 1-kanazawa-machi, Kakogawa-shi, Hyogo Kobe Steel Works, Ltd. Kakogawa Works (56) Reference JP-A-3-281736 (JP, A) JP-A-6-8247 (JP, A) JP-A-47-39124 (JP, A) JP-A-55-53622 (JP, A) JP-A-1-316428 (JP, A) JP-A-2-80526 (JP, A) JP-A-58-9939 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) F23G 5/033 B09B 3/00 B29B 17/00 C10J 3/00 C22B 1/216 F23G 7/12

Claims (2)

(57) [Claims] 1. A ground to less flat Hitoshitsubu径5mm and a steam
A method for treating a waste tire , comprising introducing a waste tire from which a cord is removed into a kiln burner of a great kiln type firing furnace in a pellet manufacturing facility for a blast furnace or a blowing nozzle provided in parallel with the kiln burner as an auxiliary fuel for firing. 2. A great kiln type firing furnace in a pellet manufacturing facility for a blast furnace, crushed to an average particle size of 5 mm or less and steel cord removed.
A calcination furnace comprising a crushed piece blowing means for introducing the waste tire thus treated into a kiln burner or a blowing nozzle provided in parallel with the kiln burner as auxiliary fuel for firing.