JP2012211755A - Mounting structure, cylindrical-furnace inner-wall structure, and construction method of cylindrical-furnace inner-wall structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure arranged in an outlet of a rotatable horizontal cylindrical furnace, in which duration of service is extended and a frequency of replacement is reduced.SOLUTION: A mounting structure is used for mounting of a refractory in a cylindrical combustion furnace. The structure includes: a plate member bending along the inner periphery of a cylinder of the combustion furnace; and a box member having a top face whose curvature is the same as that of the plate member and a side on which a recess is formed where a castable refractory gets thereinto, and being disposed at an inner-face end of the plate member.

Description

  The present invention relates to a mounting structure, a cylindrical furnace inner wall structure, and a method for constructing a cylindrical furnace inner wall.

  Rotary kilns are widely used for incineration of waste and recycled materials. A conventional rotary kiln is configured, for example, by attaching a large number of lining refractories (furnace materials) such as magnesia-chromium or magnesia-spinel fired refractory bricks to the inner wall of a cylindrical iron shell. For example, Patent Documents 1 and 2 disclose a rotary kiln using refractory bricks.

  Patent Document 3 discloses a rotary kiln that uses an irregular refractory material instead of fired refractory bricks. This configuration is formed by dividing the circumference of the inner wall of the iron shell into a plurality of portions, rotating the rotary kiln, and pouring the castable several times so that the enforcement site is directly below.

  Further, Patent Document 4 discloses a configuration in which a castable refractory layer is formed on the inner wall of an iron shell, and a cast refractory unit layer is provided on the receiver to cover and protect the castable refractory layer. .

JP-A-10-220965 JP 63-96481 A Japanese Patent Laid-Open No. 9-280738 JP 11-325743 A

  By the way, in a rotatable horizontal cylindrical furnace that treats waste, it can be rotated by continuously operating incineration treatment for 24 hours using electronic parts including precious metals, printed boards, plastics such as plastics, oils and fats, etc. Possible horizontal cylindrical furnace outlet structures were extremely brittle. For this reason, the frequency of replacement of the structure of the discharge port has increased, causing an increase in expenses related to repair work and a decrease in the operating rate of the furnace.

  Therefore, in view of the above-described problems, the present invention aims to provide a structure that is disposed at the discharge port of a rotatable horizontal cylindrical furnace, that extends the period of use and reduces the replacement frequency. To do.

The mounting structure of the present invention that solves this problem is a mounting structure that is used for mounting a refractory in a cylindrical combustion furnace, and is a plate-like member that is curved along the inner periphery of the combustion furnace. A plate-shaped member having a top surface having the same curvature as the plate-shaped member and a side surface formed with a recess into which an irregular refractory enters, and provided at an end of an inner surface of the plate-shaped member. Yes.
The mounting structure having the above structure has improved strength as compared with the conventional structure. Thereby, the structure arrange | positioned in the discharge port of the rotary kiln which extended the usable period and reduced the replacement frequency can be provided.

  In the cylindrical furnace inner wall structure of the present invention, a shell attached to the body of the combustion furnace is disposed inside the plate-like member of the mounting structure described above, and a refractory is formed on the inner periphery of the shell. An object is spread and the mounting structure is covered with an irregular refractory.

  Further, the cylindrical furnace inner wall structure may have a structure in which the inner diameter of the cylindrical furnace is equally divided into a plurality of parts in the circumferential direction, and the mounting structure is disposed in each equally divided part.

  Further, the construction method of the inner wall of the cylindrical furnace according to the present invention includes a plate-like member curved along the inner circumference of a cylindrical combustion furnace, and the same curvature as that of the plate-like member at the inner surface end of the plate-like member. A shell attached to the combustion furnace is disposed inside a mounting structure provided with a box-shaped member having a top surface of the refractory and a side surface formed with a recess into which an irregular refractory enters. This can be realized by spreading a refractory around the circumference and covering the mounting structure with an irregular refractory.

According to the present invention,
(1) It is possible to provide a structure that is disposed at the discharge port of a rotary kiln that extends the usable period and reduces the replacement frequency.
(2) Since the structure is not complicated, replacement can be performed in a short time.
(3) Furthermore, since the structure is not complicated, when the irregular refractory falls off, the irregular refractory repair work is possible and can be performed in a short time.

It is a perspective view of an attachment structure. (A) is a front view of an attachment structure. (B) is a top view of an attachment structure. (C) is a side view of the mounting structure. It is the schematic diagram which showed the exit part of the rotary kiln. It is sectional drawing of a cylindrical furnace inner wall structure. It is a perspective view of the comparison form of an attachment structure. It is a perspective view of the comparison form of an attachment structure. It is a schematic diagram of the cross section of the cylindrical furnace inner wall structure of a comparison form.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a perspective view of a mounting structure 1 according to an embodiment. FIG. 2A is a front view of the mounting structure 1. FIG. 2B is a plan view of the mounting structure 1. FIG. 2C is a side view of the mounting structure 1. The mounting structure 1 is used for mounting a refractory in a combustion furnace. In particular, the mounting structure 1 is a structure that is disposed at the outlet portion of the inner wall of a rotatable horizontal cylindrical furnace, such as a rotary kiln. The attachment structure 1 includes a plate-shaped member 11 and a box-shaped member 12.

Since the mounting structure 1 is disposed inside the rotary kiln, the plate-like member 11 has a curved shape along an arc of the inner circumference of the cylinder of the rotary kiln. The thickness of the plate-like member 11 is 35 mm at the thickest part and 22 mm at the thinnest part. The box-shaped member 12 is provided at the end of the inner surface 11 a of the plate-like member 11. The inner side surface 11a shows the surface on the side where the center of the arc is located.
The box-shaped member 12 has a width of 425 to 515 mm, a height of 250 to 300 mm, and a depth of 100 to 110 mm. The box-shaped member 12 has a top surface 12a having the same curvature as the plate-shaped member 11 and a side surface 12c in which a recess 12b is formed. In the mounting structure 1 described in the present embodiment, two concave portions 12b are formed on the side surface 12c.
When the mounting structure 1 is mounted on the rotary kiln, the irregular refractory enters the recess 12b. The depth of the recess 12b is 70 to 80 mm. Further, a protruding portion 13 is formed on the outer side surface 11 b of the plate-like member 11. The protrusion 13 is a flange formed to attach the attachment structure 1 to the rotary kiln. The protrusion 13 has a height of 60 mm and a thickness of 40 mm, and the lateral width is in accordance with a box-shaped member.
The plate-like member 11 is formed with four mounting holes 14a. Each of the recesses 12b on the side surface 12c is also formed with three Inuki holes 14b. The Inuki hole 14a has a diameter of 27 mm, and the Inuki hole 14b has a diameter of 23 mm. Here, although the two recessed parts 12b are formed, it is not limited to this, One or three or more may be sufficient. The recessed part 12b should just be a shape into which an indefinite shape refractory enters when attaching to a rotary kiln.

The mounting structure 1 may be any structure that can withstand the following mechanical properties and load conditions. That is, if vertical load: 9800N, elastic modulus: 1.4 × 10 ¹¹ N / mm ² , Poisson's ratio: 0.26, density: 7.745 kg / cm ³ , yield stress: 235 N / mm ² Good. In addition, said numerical value does not consider the heat influence. The attachment structure 1 can be formed of heat resistant steel, for example. More specifically, it can be formed by employing SCH22 (C: 0.08% or less).
Moreover, what added Nb as a steel additive may be used. Further, the mounting structure 1 forms a sprayed coating having a thickness of about 300 μm on the box-shaped member 12 and the protruding portion 13. For example, 50Ni / 50Cr is used as the thermal spray material.

Next, the cylindrical furnace inner wall structure 2 in which the attachment structure 1 is attached to the rotary kiln 3 will be described. FIG. 3 is a schematic view showing the outlet portion 4 of the rotary kiln 3. The cylindrical furnace inner wall structure 2 is disposed at the outlet portion 4 of the inner wall of the rotary kiln 3.
A plurality of refractories (formed bricks) 5 are laid on the inner wall of the rotary kiln 3. The rotary kiln 3 has an inner diameter of 3700 mm and an outer diameter of 3960 mm when the refractory 5 is attached. At the outlet portion 4 of the rotary kiln 3, the inner diameter of the cylindrical furnace is equally divided into a plurality of portions in the circumferential direction, and the mounting structure 1 is disposed in each equally divided portion. In the present embodiment, the cylindrical furnace is divided into 24 equal parts, and the mounting structures 1 are arranged on each of them, and the refractory 5 is laid. Hereinafter, this configuration will be described in detail.

FIG. 4 is a cross-sectional view of the cylindrical furnace inner wall structure 2. The cylindrical furnace inner wall structure 2 includes a mounting structure 1, a shell 6, a refractory 7, and an amorphous refractory 8. In the cylindrical furnace inner wall structure 2, the shell 6 is arranged inside the plate-like member 11 of the mounting structure 1, and the refractory 7 and the refractory 5 are spread on the inner periphery of the shell 6, so that the mounting structure 1 is not attached. Covered with regular refractory 8 and constructed.
Hereinafter, the configuration of the cylindrical furnace inner wall structure 2 will be described in detail.

  The base end portion of the shell 6 is attached to an existing body 31 in the rotary kiln 3. The mounting structure 1 is disposed on the outlet side of the shell 6, and the amorphous refractory 8 is constructed and fixed. The irregular refractory 8 covers the tip of the mounting structure 1 and the shell 6 from the top of the anchors 9a, 9b, 9c, 9d.

Such an amorphous refractory 8 is preferably a substance having a melting point higher than that of the incineration residue and a low thermal expansibility, and has many functional characteristics such as heat dissipation characteristics, hardness, wear resistance, corrosion resistance, high temperature strength, and thermal shock resistance. An alumina-based castable provided, for example, alumina-chromia can be employed.
A castable is a refractory material in which a refractory aggregate and hydraulic cement (alumina cement or the like) are mixed. The feature of the castable is that the castable itself can form a one-piece fire wall that works in the same way as fire bricks and heat insulating bricks. The castable can be selected from those that place importance on fire resistance, those that place importance on heat insulation, and those that have both fire resistance and heat insulation. In addition, there are a usage type, a casting type, and a spraying type.
The use of castables will be explained for common cast-type and glazed types. Add the specified amount of water to castable (hot water, salt water, additives, etc. cannot be used). Use only normal water and stir and mix using a mixer etc. within 30 minutes. Normal castables can be used after being cured in about 24 hours at an air temperature of 20 ° C. or higher.
During construction, pay close attention to the amount of mixed water (usually expressed as a percentage of the castable weight) and temperature. The amount of water will be within the specified range, and the temperature will be over 20 degrees and within 30 minutes. Curing after the placement work is done so that the construction part does not dry and freeze.
For such a castable, one whose main component is MgO can be used.

  As the material of the anchors 9a, 9b, 9c, 9d, for example, stainless steel SUS316L can be adopted. Each anchor is provided for each Inuki hole of the mounting structure 1 and at a predetermined position. Each of these anchors prevents misalignment of the irregular refractory. The height in the radial direction of the rotary kiln 3 of the irregular refractory 8 thus constructed is 450 to 480 mm, and the depth is 450 to 500 mm.

Three refractories 7 are spread from the site where the irregular refractory 8 is constructed toward the entrance side of the rotary kiln 3. At the end of the refractory 7 on the inlet side, the refractory 5 is laid continuously. The refractory 5 and the refractory 7 can use bricks having the same composition.
However, when the height of the refractory 5 is 250 mm, the height of the refractory 7 is 350 mm higher by 100 mm. The refractory 5 is continuously spread on the existing body 31.

The cylindrical furnace inner wall structure 2 configured as described above prevents the refractories 5 and 7 and the amorphous refractory 8 from falling. In particular, since the mounting structure 1 is formed with the recess only on the side surface, the structure is high in strength, and deformation is suppressed even in discharging high-temperature incineration residue. By suppressing the deformation in this way, the usable period (life) becomes longer and the replacement frequency can be reduced. As a result, the usable period (life) of the cylindrical furnace inner wall structure 2 can be extended, and the replacement frequency can be reduced.
Moreover, in the mounting structure 1 of embodiment of this invention, the usable period (life) is extended by forming a thermal spray coating. For example, when the usable period of the mounting structure in which the thermal spray coating was not formed was 3 months, the usable period was extended by 1 month after the thermal spray coating was formed.
In the configuration of this embodiment, the inner diameter of the cylindrical furnace is divided into 24 equal parts, but the number of equally divided parts may be changed depending on the size of the rotary kiln.
(Comparison form)

  Subsequently, a form to be compared will be described. 5 and 6 are perspective views of comparative forms of the mounting structure. The mounting structure 101 of FIG. 5 is different from the present embodiment in that it includes two separated top surfaces 112a and 112b. The mounting structure 201 of FIG. 6 also differs from the present embodiment in that it includes two separated top surfaces 212a and 212b.

  Next, the cylindrical furnace inner wall structure 102 of a form to be compared will be described. FIG. 7 is a schematic view of a cross section of a cylindrical furnace inner wall structure 102 of a comparative form. The cylindrical furnace inner wall structure 102 includes an attachment structure 101 instead of the attachment structure 1. In the cylindrical furnace inner wall structure 102, the shell 106 is disposed inside the mounting structure 101, the refractory 5 is spread on the inner periphery of the shell 106, and the mounting structure 101 is fixed to the irregular refractories 108a, 108b, 108c, 108d and coated. The irregular refractory 108 a is fixed to the shell 106 by a metal retaining bolt 109. Furthermore, the radial height of the irregular refractory 108d at the outlet of the rotary kiln 3 is 600 mm. Other configurations are the same as those of the present embodiment.

Examples based on the above embodiment will be described below. In rotary kiln 3 provided with cylindrical furnace inner wall structure 2 in the above-mentioned embodiment, incineration residue at a high temperature of 1200 to 1250 ° C. (SiO ₂ : 20 to 28%, Fe ₂ O ₃ : 15 to 22%, CuO: 12 to 15%) is discharged from 1300t to 1600t per month by continuous operation for 24 hours.
The cylindrical furnace inner wall structure 2 becomes brittle with the operation, but the usable period (life) of the cylindrical furnace inner wall structure 2 is 6 months or more.

  The structure of the inner wall of a conventional cylindrical furnace has a usable life of only about 2 months, and the life of the steel plate has been extended by repairing the iron plate. However, this iron plate is severely worn by incineration heat, and the usable life after the repair of the iron plate is also 1 month. (Replacement of advanced hardware was carried out three times a year). Furthermore, replacement work for the structure of the inner wall of the cylindrical furnace required one week. Therefore, in the past, it was necessary to provide a repair period of six times a year, and the operation was stopped for at least six weeks only by the repair work. In this embodiment, the repair can be performed twice a year or less, so that the time stopped by the repair work can be reduced by 4 weeks. The amount of incineration can be increased by shortening the repair work. In addition, the cost for repair work can be reduced by approximately 100 million yen per year.

  Moreover, in the rotary kiln provided with the cylindrical furnace inner wall structure 102 in the comparative embodiment, the usable period of the cylindrical furnace inner wall structure 102 is 4 months, and therefore the usable period of the cylindrical furnace inner wall structure 2 of the present embodiment. Is shown to have been extended.

  Differences between the mounting structure 1 according to the embodiment of the present invention and the mounting structures 101 and 201 according to comparative embodiments will be described. In the attachment structures 101 and 201 of the comparative form, the top surfaces are provided separately. For this reason, at the stage of installing the irregular refractory when attaching to the rotary kiln, the irregular refractory penetrates between the separated top surfaces, and the irregular refractory penetrates in the radial direction of the cylindrical furnace. . On the other hand, since the mounting structure 1 according to the embodiment of the present invention includes the continuous top surface 12a that is not separated, the amorphous refractory does not enter the radial direction of the cylindrical furnace during construction.

Mounting structure 1, 101, 201 is arrange | positioned in the discharge part which discharges 1300t-1600t per incineration residue of 1200-1250 degreeC. If the upper structure is open (like the shape where the top surface is separated) like the mounting structures 101 and 201 of the comparative form, the steel frame becomes weak under the influence of the heat of the incineration residue, The strength tends to be low and the replacement frequency cannot be reduced.
On the other hand, the structure of the mounting structure 1 according to the present embodiment, in which only the side surface on the outlet side of the furnace was opened, was confirmed from the operation results that the deformation due to the influence of heat is suppressed and the strength is maintained. . This prevents the refractory from falling, extends the usable period of the structure at the outlet of the furnace, and reduces the replacement frequency. As a result, the amount of incinerated materials can be increased and the repair cost can be reduced.

  Furthermore, since the configuration of the present invention is not complicated, the work performed at the time of periodic repair is extremely easy, and the work time can be reduced and the burden on the worker can be reduced.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope.

DESCRIPTION OF SYMBOLS 1 Mounting structure 11 Plate-shaped member 12 Box-shaped member 12a Top surface 12b Recessed part 12c Side surface 2 Cylindrical furnace inner wall structure 3 Rotary kiln 5 Refractory 6 Shell 7 Refractory 8 Indeterminate refractory

Claims (4)

A mounting structure used for mounting a refractory in a cylindrical combustion furnace,
A plate-like member curved along the inner periphery of the cylinder of the combustion furnace;
Mounting having a top surface having the same curvature as that of the plate-like member and a box-like member provided at an end of the inner surface of the plate-like member, having a side surface formed with a recess into which an irregular refractory enters. Structure.   A shell attached to a body of a combustion furnace is disposed inside the plate-like member of the mounting structure according to claim 1, and a refractory is spread on the inner periphery of the shell, so that the mounting structure is indefinite. Cylindrical furnace inner wall structure coated with refractory.   The cylindrical furnace inner wall structure according to claim 2, wherein an inner diameter of the cylindrical furnace is equally divided into a plurality of parts in a circumferential direction, and the mounting structure is disposed in each of the divided parts. A plate-shaped member curved along the inner circumference of a cylindrical combustion furnace, a top surface having the same curvature as the plate-shaped member, and a recess into which an irregular refractory enters the inner surface end of the plate-shaped member. A shell attached to the combustion furnace is disposed inside the mounting structure provided with a box-shaped member having a formed side surface;
A method for constructing an inner wall of a cylindrical furnace in which a refractory is spread on the inner periphery of the shell, and the mounting structure is covered with an irregular refractory.

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