JP2013044482A - Method of repairing furnace wall of rotary kiln - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of repairing a furnace wall of a rotary kiln capable of repairing the furnace wall by replacing only a refractory having severe damage.SOLUTION: In this method of repairing the furnace wall 3 of the rotary kiln A configured by arranging the plurality of refractories 2 having a trapezoidal shape in a plane view while covering an inner face 1a of a cylindrical body 1, a thickness Hr of the refractory 2 satisfying the relationship of Hn>Hr>Hm when an initial thickness of the refractory 2 is Hn and a thickness of the refractory 2 predetermined as a management value requiring repairing, is Hm, is determined in advance, the furnace wall 3 is partially broken up by removing the refractory 2 having the thickness smaller than the thickness Hr, when the refractory 2 having the thickness smaller than the management value Hm is detected, and a new refractory 4(2) having a thickness Hr is placed on a part from which the refractory 2 is removed, thus the furnace wall 3 is repaired.

Description

  The present invention relates to a furnace wall repair method for a rotary kiln.

  Conventionally, rotary kilns are used as cement, quicklime, mineral firing furnaces, industrial waste incinerators, melting furnaces, and the like. In the rotary kiln, the inner peripheral surface of a cylindrical iron shell that is a body is covered with a refractory material such as a fired refractory brick to form a furnace wall. Furthermore, in general, the refractory is not fixed to the inner peripheral surface of the iron shell to form the furnace wall, but the refractory is formed in a trapezoidal shape in plan view and locked in the circumferential direction of the iron shell. A plurality of refractories are juxtaposed in the circumferential direction so as not to fall off and form a furnace wall (see, for example, Patent Document 1).

  Such a refractory (furnace wall) of a rotary kiln is gradually damaged (worn) due to deterioration caused by exposure to high temperatures over a long period of time, for example, slag components generated when incinerating and melting industrial waste. . And if a refractory is damaged and the thickness becomes small, inconveniences such as high temperature acting on the iron shell will cause deformation and corrosion with acid gas will occur. Moreover, if the refractory is damaged and its thickness is reduced, it will easily fall off. For this reason, for example, half the thickness of the refractory is used as a control value, and when the refractory is damaged to the thickness of the control value, the refractory is replaced to repair the furnace wall.

JP 2003-106770 A

  On the other hand, since the rotary kiln has a non-uniform combustion state in the axial direction from the raw material inlet to the outlet, the degree of damage to the refractory forming the furnace wall varies depending on the part. However, in the past, partial refractory repairs have been limited to cases where the refractory is severely damaged or where the refractory has fallen off. All the refractories are replaced with new refractories when the remaining thickness of the steel falls below the control value, and all furnace repairs are performed to re-form the furnace walls.

  In other words, in rotary kilns, the degree of damage to the furnace wall often varies greatly depending on the position in the axial direction, and when the remaining thickness of the refractory falls below the control value at a certain location, it is necessary to repair the furnace wall. However, most of the refractories are small in damage and often usable sufficiently, but all the refractories are replaced with new refractories, and the furnace wall is reshaped.

  In addition, in a melt-type rotary kiln that melts raw materials such as industrial waste, if a refractory is partially replaced with a new one, a level difference will occur, and the melt (melted material) will be blocked by the level difference. Thus, the inconvenience occurs that the melt flows down rapidly and the refractory is locally worn. For this reason, with conventional rotary kilns in particular, all refractories should be replaced with new refractories when some of the refractories have fallen below the control value from the viewpoint of preventing the occurrence of steps. The furnace wall is reformed.

  Then, by replacing the refractory with less damage with a refractory less than the control value, new refractory for the entire circumference of the rotary kiln is required, and the preparation period and construction period required for repair are prolonged. In addition, there was a problem that a large economic burden was generated.

  In addition, the amount of used refractory is increased because the refractory with less damage is replaced. For example, refractories containing chromia are generally used in melting furnaces for industrial waste, and the refractory containing chromia may leach out hexavalent chromium, which is a harmful heavy metal. Chemical treatment such as is necessary. For this reason, since the generation amount of a used refractory increases, a big economic burden arises too. In addition, the environmental load increases.

  In addition, there is also a method of repairing the furnace wall by increasing the thickness of the furnace wall (thick refractory) by spraying a material with excellent fire resistance (unshaped refractory) and increasing the thickness of the furnace wall. The fired refractory may be peeled off due to expansion / contraction due to heat or external force acting when the rotary kiln is rotated, and a sufficient effect may not be obtained.

  In order to solve the above problems, the present invention provides the following means.

  The furnace wall repair method for a rotary kiln of the present invention is a method for repairing a furnace wall of a rotary kiln formed by arranging a plurality of trapezoidal refractories in parallel so as to cover the inner peripheral surface of a cylindrical body. The initial thickness of the refractory is set to Hn, the thickness of the refractory set in advance as a management value requiring repair is set to Hm, and the thickness Hr of the refractory satisfying the relationship of Hn> Hr> Hm is set. When the refractory having a thickness lower than the control value Hm is detected in advance, the refractory lower than the thickness Hr is removed to partially dismantle the furnace wall, and the refractory is removed. The furnace wall is repaired by installing a new refractory having a thickness of Hr in the part.

  Moreover, in the furnace wall repair method of the rotary kiln of the present invention, when the area range of the furnace wall that is partially dismantled by removing the refractory below the thickness Hr exceeds a preset area range, It is desirable to remove all the refractories and re-form all of the furnace walls.

  Furthermore, in the furnace wall repair method for a rotary kiln of the present invention, the thickness Hr is Hr = Hn / 2, and the refractory piece obtained by dividing the refractory having the thickness Hn into two equal parts in the thickness direction is used as the new refractory. It is more desirable to use as a product.

  In the furnace wall repair method of the rotary kiln of the present invention, when a refractory whose thickness is less than the control value Hm is detected, the refractory that is less than the thickness Hr is removed, and the portion where the refractory is removed is thickened. By installing a new refractory with a height of Hr and repairing the furnace wall, it is possible to repair the furnace wall by replacing only the refractory that is relatively damaged. For this reason, it is possible to shorten the preparation period and the construction period required for repair as compared with the case where all the refractories are replaced with new refractories as in the past, and economically required for furnace wall repair. The burden can be reduced. In addition, since the amount of used refractory is reduced, the economic burden required for the processing can be reduced. This makes it possible to reduce the running cost of the rotary kiln compared to the conventional case.

  Moreover, in order to repair the furnace wall by removing a refractory having a thickness less than Hr and installing a new refractory having a thickness of Hr on the part where the refractory is removed, a new refractory is partially added. There is no step even after replacement. For this reason, even if it is a melt-type rotary kiln, the melt (melted raw material) is blocked by a step, or the melt suddenly flows down at the step and the refractory is locally worn away. Can be reliably prevented from occurring.

  In the method of repairing a furnace wall of a rotary kiln according to the present invention, the refractory having a thickness less than Hr is removed and the furnace wall is partially disassembled and repaired. Based on economic comparisons when re-forming everything, an area range is set in which all refractories are removed and all of the furnace walls are re-formed. And, when the area range of the furnace wall to be partially dismantled by removing the refractory below the thickness Hr in advance exceeds the preset area range, the efficiency of the furnace wall is improved The furnace wall can be repaired efficiently and economically.

  Further, in the furnace wall repair method of the rotary kiln according to the present invention, a refractory piece obtained by dividing the refractory having a thickness Hr into two in the thickness direction is used as a new refractory. As a result, we have only refractory with a thickness of Hn as a normal stock, and even if it is necessary to repair the furnace wall immediately by cutting this refractory into two equal parts, It can respond flexibly. For this reason, it is not necessary to separately have a refractory for repair.

It is a figure which shows the rotary kiln which concerns on one Embodiment of this invention. FIG. 2 is a cross-sectional view of the rotary kiln according to the embodiment of the present invention, taken along line X1-X1 in FIG. FIG. 2 is a cross-sectional view of the rotary kiln according to the embodiment of the present invention, taken along line X2-X2 in FIG. It is a figure which shows the furnace wall repair method of the rotary kiln which concerns on one Embodiment of this invention. It is a figure which shows a refractory. It is a figure which shows the refractory material used with the furnace wall repair method of the rotary kiln which concerns on one Embodiment of this invention.

  Hereinafter, a furnace wall repair method for a rotary kiln according to an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

  First, as shown in FIG. 1 to FIG. 3, the rotary kiln A of the present embodiment has a fixed shape refractory such as fired refractory bricks in the circumferential direction T <b> 1 along the inner peripheral surface 1 a of the cylindrical shell 1 that is the body. 2 are juxtaposed, and the furnace wall 3 is formed by covering the inner peripheral surface 1 a of the iron shell 1 with the refractory 2. Further, the rotary kiln A of the present embodiment is formed, for example, with a length in the axial direction O1 of about 14 m and an outer diameter of about 6 m.

  2, 3, and 6, the refractory 2 is formed in a trapezoidal shape (in the shape of a sectional fan) in a plan view in the axial direction O <b> 1 of the rotary kiln A, and is mutually in the circumferential direction T <b> 1 of the iron shell 1. A furnace wall 3 is formed by fitting a plurality of refractories 2 in the circumferential direction T <b> 1 so as to be locked to each other and not fall off.

  Next, in the furnace wall repair method of the rotary kiln A of the present embodiment, as shown in FIG. 4A, first, the initial thickness of the refractory 2 is set to Hn, and the fire resistance is set as a control value that requires furnace wall repair. The thickness Hm of the object 2 is set in advance. Furthermore, the thickness Hr of the refractory 2 that satisfies the relationship of Hn> Hr> Hm is set in advance. The thickness Hr of the refractory 2 is the thickness of the furnace wall 3 to be recovered by repairing the furnace wall.

  Here, when the rotary kiln A is operated, as shown in FIG. 4 (b), the furnace is caused by deterioration due to high temperature exposure over a long period of time, slag components generated when incinerating and melting raw materials such as industrial waste, etc. The wall 3 is gradually damaged (worn).

  And in the furnace wall repair method of the rotary kiln A of this embodiment, as shown in FIG.4 (b), when the refractory 2 whose thickness is less than the control value Hm is detected, all the refractory like in the past is detected. Instead of replacing the object 2 with a new refractory 2 and re-forming the furnace wall 3, only the refractory 2 below the thickness Hr is removed to remove the furnace wall 3 as shown in FIG. As shown in FIG. 4D, the furnace wall 3 is repaired by installing a new refractory 2 (4) having a thickness of Hr in the part where the refractory 2 is removed, as shown in FIG.

  In this way, the furnace wall 3 can be repaired by replacing only the refractory 2 with relatively large damage, and compared with the case where all the refractories 2 are replaced with new refractories 2 as in the past. The preparation period and construction period required for this will be shortened. Moreover, the generation amount of the used refractory 2 is small.

  On the other hand, when such a repair is repeated a plurality of times, the area range of the furnace wall 3 where the refractory 2 below the thickness Hr is removed and partially disassembled gradually increases. On the other hand, in the furnace wall repair method of the rotary kiln A of the present embodiment, every time repair work is performed, the refractory 2 below the thickness Hr is removed and the furnace wall 3 is partially disassembled and repaired. Area when re-forming all of the furnace walls 3 based on economic comparison when removing all of the refractory 2 and re-forming all of the furnace walls 3, as well as the operating conditions and operation plan of the rotary kiln A Is set in advance.

  And when the area range of the furnace wall 3 which removes the refractory 2 below the thickness Hr and partially disassembles exceeds the preset area range, the entire furnace wall 3 is repaired. Thus, by determining whether or not the entire furnace needs to be repaired, the furnace wall 3 can be repaired efficiently and economically. For example, when the area of the refractory 2 that is less than the thickness Hr exceeds half the area of the entire furnace wall 3, all the refractory 2 is removed and the entire furnace wall 3 is formed again. May be.

  Here, when repairing the furnace wall 3 of the rotary kiln A as described above, the thickness of the refractory 2 is periodically measured (detected), and whether or not the thickness of the refractory 2 is below the control value Hm. It is good to determine.

  In addition, since the thickness of the refractory 2 being used varies depending on the furnace, the thickness Hr may have to be set to a value close to the control value thickness Hm. In this case, after the repair, the thickness of the refractory 2 may fall below the control value Hm at an early stage, and the repair frequency may increase. For this reason, it is preferable to take measures to ensure a sufficient initial thickness Hn of the refractory 2. That is, for example, in the furnace using the refractory 2 having an initial thickness Hm of 350 mm and a control value Hm of 100 mm, if the thickness Hr is set to 175 mm, the damage margin after repair is only 75 mm. The frequency of repairs will increase. For this reason, the initial thickness Hm is set to 400 mm or more to ensure a large thickness, and the thickness Hr can be set to 200 mm or more. In this way, it is possible to secure a damage margin of 100 mm or more after repair, and it is possible to keep the frequency of repair low.

  Moreover, in the furnace wall repair method of the rotary kiln A of this embodiment, as shown in FIGS. 5A and 6A, the thickness Hr is set to Hr = Hn / 2, and the initial fire resistance of the thickness Hn is set. The object 2 may be cut into two equal parts in the thickness direction, and the furnace wall 3 may be repaired using the refractory pieces 4a and 4b having a thickness of Hr as the new refractory 4. In this case, the refractory 2 having a thickness of Hn that is owned as a normal stock can be used as the refractory 4 for repair.

  On the other hand, the refractory 2 is formed in a trapezoidal shape in plan view according to the curvature of the inner peripheral surface 1a of the iron shell 1 so that the inner peripheral surface 1a of the iron shell 1 can be covered. For this reason, when the refractory 2 is divided into two in the thickness direction, the section on the front end surface side that forms the inner peripheral surface of the furnace wall 3, the rear end surface side arranged on the outer peripheral surface side of the furnace wall 3 Two refractory pieces 4a and 4b (two refractory pieces having different sizes) having different sections are formed. And if repair is performed using the refractory piece 4a having a small size as a new refractory 4 as shown in FIG. 5 (b), the refractory 4 (4a) is insufficiently stretched, and the iron shell shell The force of mutually locking the refractories adjacent to each other in the circumferential direction is insufficient, and dropout (dropout) is likely to occur.

  On the other hand, when applying the furnace wall repair method of the rotary kiln A of the present embodiment and repairing using the refractory pieces 4a and 4b obtained by dividing the refractory 2 into two in the thickness direction, for example, As shown in FIG. 5 (a), when the thickness is 1, the width of the upper end (width dimension in the circumferential direction T1 on the inner peripheral surface side of the furnace) is 0.24, and the width of the lower end (outer peripheral surface side of the furnace) In contrast to the conventional refractory 2 having a width dimension in the circumferential direction T1 of 0.28 and a depth (width dimension in the axial direction O1 of the furnace) of 0.43, a> 0.24, b> 0.28, The values of a, b, and c are determined so that the value of c> 0.43 and a × c does not greatly deviate from the conventional value of 0.24 × 0.43. As shown in FIG. It is preferable to use a refractory 2 having a, b at the lower end, and c at the lower end. That is, by previously increasing the width dimension in the circumferential direction T1 of the furnace to form the refractory 2, the refractory 2 is divided into two equal parts in the thickness direction as shown in FIG. Even when repairing using a small refractory piece 4a as a new refractory 4, it is possible to secure the clogging of the refractory 4 and to prevent dropping.

  Further, by installing the refractory 4 while applying mortar or the like between the refractories 4 adjacent to each other in the circumferential direction T1, it is possible to absorb the mismatch to some extent and make it difficult to drop off even if the sag is insufficient. Although it is possible, it is still a good idea to increase the width dimension of the refractory 4 in the circumferential direction T1 and secure the burr as described above in order to prevent the dropout more reliably.

  Even if the width dimension in the circumferential direction T1 is increased, the refractory 2 is divided into two equal parts, and the weight of the refractory 4 is kept low by reducing the depth. Therefore, workability at the time of installing the refractory 4 is not impaired.

  Therefore, in the furnace wall repair method of the rotary kiln A of the present embodiment, when the refractory 2 having a thickness below the control value Hm is detected, the refractory 2 below the thickness Hr is removed, and this refractory 2 By installing a new refractory 4 (2) having a thickness of Hr to repair the furnace wall 3 in the part where the metal was removed, only the refractory 2 with relatively large damage was replaced and the furnace wall was replaced. 3 repairs can be performed.

  For this reason, compared with the case where all the refractories 2 are replaced with new refractories 2 as in the prior art, it is possible to shorten the preparation period and the construction period required for repair and to repair the furnace wall. Economic burden can be reduced. Moreover, since the generation amount of the used refractory 2 is reduced, the economic burden required for the processing can be reduced. As a result, the running cost of the rotary kiln A can be reduced compared to the conventional case.

  Moreover, as shown in FIG.4 (c), FIG.4 (d), the refractory 2 below thickness Hr is removed, and the new refractory 4 with thickness Hr is removed in the part which removed this refractory 2 Therefore, even if a new refractory 4 is partially replaced, there is no step (large step). For this reason, even in the melt type rotary kiln A, the melt (melted raw material) is blocked by a step, or the melt suddenly flows down at the step and the refractories 2 and 4 are locally worn. It is possible to reliably prevent inconveniences such as

  Moreover, the economy in the case of removing the refractory 2 below the thickness Hr and partially dismantling and repairing the furnace wall 3 and removing all the refractory 2 and re-forming all of the furnace wall 3 Based on the comparison or the like, an area range in which all the refractories 2 are removed and all of the furnace walls 3 are formed is set in advance. And when the area range of the furnace wall 3 which removes the refractory 2 less than the thickness Hr in advance and partially disassembles exceeds the preset area range, the entire furnace wall 3 is repaired. Thereby, it becomes possible to repair the furnace wall 3 efficiently and economically.

  Furthermore, by setting the thickness Hr to Hr = Hn / 2 and using the refractory pieces 4a and 4b obtained by dividing the refractory 2 having the thickness Hn into two equal parts in the thickness direction, the new refractory 4 is used. Even if the refractory 2 having a thickness of Hn is only owned and the refractory 2 is cut and divided into two equal parts, it is possible to immediately and flexibly cope with the case where the repair of the rapid furnace wall 3 becomes necessary. be able to. For this reason, it is not necessary to separately have a refractory for repair.

  As mentioned above, although one Embodiment of the furnace wall repair method of the rotary kiln of this embodiment was described, this invention is not limited to said one Embodiment, It can change suitably in the range which does not deviate from the meaning.

1 Iron shell (fuselage)
1a inner peripheral surface 2 refractory 3 furnace wall 4 refractory (refractory for repair)
4a Refractory piece 4b Refractory piece A Rotary kiln O1 Axis direction T1 Circumferential direction

Claims (3)

A method of repairing a furnace wall of a rotary kiln formed by arranging a plurality of refractories having a trapezoidal shape in plan view so as to cover the inner peripheral surface of a cylindrical body,
The initial thickness of the refractory is set to Hn, the thickness of the refractory set in advance as a management value requiring repair is set to Hm, and the thickness Hr of the refractory satisfying the relationship of Hn>Hr> Hm is set in advance. Set,
When the refractory having a thickness lower than the control value Hm is detected, the refractory lower than the thickness Hr is removed to partially dismantle the furnace wall, and the refractory is removed. A furnace wall repair method for a rotary kiln, wherein a new refractory having a thickness of Hr is installed to repair the furnace wall. In the furnace wall repair method of the rotary kiln according to claim 1,
When the area range of the furnace wall that is partially dismantled by removing the refractory that is less than the thickness Hr exceeds a preset area range, all the refractories are removed and all of the furnace wall is removed. A method for repairing a furnace wall of a rotary kiln, characterized by re-forming. In the furnace wall repair method of the rotary kiln according to claim 1 or claim 2,
A furnace wall repair method for a rotary kiln, wherein the thickness Hr is Hr = Hn / 2, and a refractory piece obtained by dividing the refractory having the thickness Hn into two equal parts in the thickness direction is used as the new refractory. .

Images