JP2008020143A - Repairing method for fire resistant wall surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a repairing method for a fire resistant wall surface forming a thermal spraying material layer with high surface smoothness and superior external shock resistance in a method for repairing an deficit part of a fire resistant wall surface by forming a thermal spraying material layer. <P>SOLUTION: Thermal spraying material is sprayed on the deficit part 2 formed on the fire resistant wall surface 1 of a coke oven carbonization chamber, a thermal spraying material layer 3 is filled and formed on the deficit part 2, a non deficit face of the carbonization chamber wall 1 becomes substantially flush with a surface of the thermal spraying material layer 3, and there are uneven parts on the surface of the thermal spraying material layer 3. A laser beam is irradiated on the surface of the thermal spraying material layer 3 to reduce the uneven parts of the surface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for repairing a defective refractory wall, and more particularly to a method for repairing a refractory wall having high smoothness after the repair.

  Coke is produced through coal filling into the carbonization chamber of the coke oven, dry distillation of the coal, and discharge of the coke generated by the dry distillation to the outside of the coke oven, and the coke is mass-produced by repeating these fillings. For the dry distillation of coal filled in the carbonization chamber, for example, conditions of 1000 ° C. and 20 hours are required. Cracks such as cracks and peeling may occur on the wall surface of the coke oven carbonization chamber in which such high temperature dry distillation is performed.

  If the wall of the coke oven chamber is damaged, it will be expensive to introduce a new coke oven. Here, as a thermal spray repair method, (1) a flame spraying method in which a thermal spraying material such as a powder refractory is sprayed from a nozzle to a defective portion through a combustion flame such as a mixed gas of propane and oxygen, (2) There is known a thermite spraying method in which a thermal spray material sprayed on a defect portion is welded to the defect portion by thermite reaction heat.

  The defective part can be repaired by flame spraying method or thermite spraying method, but the sprayed material layer formed on the defective part due to the fact that the aggregate which is one component of the sprayed material did not melt in the repair process Innumerable irregularities are generated on the surface of the film. Carbon easily adheres to the unevenness, and sometimes grows into a protruding carbon mass. The adhering protruding carbon increases the pushing force required to push the coke out of the coke oven, and as a result, the problem that the coke is clogged or the repaired part is lost again occurs. Therefore, it is desired to reduce the unevenness on the surface of the thermal spray material layer and increase the smoothness of the surface.

  As a method for smoothing the surface of the formed thermal spray material layer, there is a method of smoothing the surface with a trowel or a chisel (see, for example, Patent Documents 1 and 2). In these methods, the surface of the refractory brick and the surface of the sprayed material layer that make up the coke oven carbonization chamber wall are substantially flush, and the surface of the refractory brick and the surface of the sprayed material layer are made to have the same level of smoothness. is there.

As a method for smoothing the surface of the thermal spray material layer, the applicant has proposed a method of heating the surface of the thermal spray material layer to 1300 ° C. or higher with a combustion flame (see Patent Document 3). Since this method can melt the spray material component such as aggregate contained in the spray material layer without melting, the smoothness of the surface of the spray material layer can be increased. On the other hand, a fine crack is generated in the sprayed material layer that is rapidly heated by the combustion flame.
JP-A-9-302354 Japanese Patent Laid-Open No. 2000-212566 JP 2006-56993 A

  In view of the above circumstances, the present invention is a method for forming a thermal spray material layer and repairing a defective portion of a refractory wall, and forms a thermal spray material layer having high surface smoothness and excellent external impact resistance. The purpose is to provide a method for repairing fireproof walls.

  The present invention is a method for repairing a refractory wall by forming a sprayed material layer on a defect portion of the refractory wall and irradiating the surface of the sprayed material layer with laser light. The refractory wall to be repaired by this method includes, for example, the wall of a coke oven carbonization chamber.

  According to the present invention having the above-described configuration, the surface of the formed thermal spray material layer is irradiated with laser light to smooth the surface, so that the thermal spray material layer having high smoothness and excellent external impact resistance is fireproof. It is formed in the defect part of the wall surface.

  The present invention will be described based on an embodiment. The method according to the present embodiment is a method for repairing a coke oven carbonization chamber wall surface in which a sprayed material layer is formed on a defect portion generated on the wall surface of the coke oven carbonization chamber and the surface of the sprayed material layer is smoothed. FIG. 1 is a view for explaining a repairing method according to the present embodiment, and defects on the wall surface of the carbonizing chamber are repaired by the procedure shown in FIGS. 1 (a) to 1 (e). Hereinafter, the method according to the present embodiment will be described with reference to FIG.

  Fig.1 (a) is a cross-sectional schematic diagram showing the carbonization chamber wall in which coke is manufactured by dry distillation of coal. The carbonization chamber wall 1 is composed of refractory bricks that can withstand the temperature for performing coal carbonization, and a defect portion 2 is present on the surface thereof.

  FIG. 1B is a schematic diagram showing a process of spraying the spray material onto the defect portion 2 and forming the spray material layer 3 on the defect portion 2.

As the thermal spray material used for forming the thermal spray material layer 3, any material may be used as long as it is a material usually used for repairing a defect portion. For example, when repairing a defective portion using thermite reaction heat, a powder mixture of aggregate and heat generating material is used as a thermal spray material. As the thermal spraying material at this time, the aggregate is 90% by mass or more of silicon dioxide (SiO ₂ ), the heating material is metal silicon (Si) powder, and aluminum oxide (Al ₂ O ₃ ), calcium oxide (CaO) ), Magnesium oxide (MgO), iron oxide (Fe ₂ O ₃ ), potassium oxide (K ₂ O), or one or more metal oxides such as sodium oxide (Na ₂ O) in a proportion of 10% by mass or less Can be mentioned.

  The thermal spraying method is not particularly limited, such as thermite spraying method, flame spraying method, plasma spraying method and the like.

  FIG. 1C shows the carbonization chamber wall 1 after the formation of the thermal spray material layer 3 is completed. The thermal spray material layer 3 is filled and formed in the defect portion 2, and the non-defect surface of the carbonization chamber wall 1 and the surface of the thermal spray material layer 3 are substantially flush with each other. There are irregularities that lower the smoothness.

FIG.1 (d) is a figure showing the state which smoothes the unevenness | corrugation in the surface of the thermal spray material layer 3 of FIG.1 (c). In the present embodiment, the surface of the thermal spray material layer 3 is irradiated with the laser beam 4 to reduce the unevenness of the surface. The laser used here is a CO ₂ laser.

When irradiating the CO ₂ laser, the spray material layer 3 may be irradiated with laser light output in a continuous form. At this time, when the wall temperature of the carbonization chamber wall 1 is 600 to 800 ° C., the scanning speed of the laser beam is preferably about 1 to 4 m / min, and the output density of the laser beam is preferably about 1.1 kW / Φ20 mm. In addition, it is necessary to set the output of a laser beam to high density, so that wall surface temperature is low.

  FIG. 1 (e) is a diagram illustrating a state in which the surface of the thermal spray material layer 3 is smoothed by the laser beam 4, and illustrates a state in which the defect portion repair of the carbonization chamber wall 1 has been completed. As shown in the drawing, the smoothness of the surface of the thermal spray material layer 3 in which the unevenness of the surface is reduced is increased by the irradiation of the laser beam 4.

(Experimental example)
Hereinafter, the present invention will be described by experimental examples.
By a thermite spraying method, a sprayed material layer having a length of 100 mm, a width of 100 mm, and a thickness of 60 mm was sprayed and formed on one surface of the refractory brick, and the surface of the sprayed material layer was irradiated with laser light. Then, surface roughness measurement, carbon adhesion strength measurement, and wear resistance test were performed on the thermal spray material layer irradiated with laser light. The details of the sprayed material used, spraying conditions of the sprayed material, and laser light irradiation conditions, as well as surface roughness measurement, carbon adhesion strength measurement, and wear resistance test are as follows.

(Spraying material)
“FG-512D (2)” manufactured by Nippon Special Furnace Co., Ltd. having the following composition was used.
Aggregate which is a powder mixture having a maximum particle size of 1.5 mm, in which 6% by mass of metal oxide (Fe ₂ O ₃ , Al ₂ O ₃ , CaO, MgO) is mixed with 94% by mass of silicon dioxide (SiO ₂ ). And a thermal spray material composed of a heat generating material that is metal silicon (Si) powder.

(Spraying material spraying conditions)
Spraying material spraying amount: 50 kg / hr
Oxygen flow rate: 25 Nm ³ / hr

(Laser irradiation conditions)
Laser beam: CO ₂ laser Laser beam scanning speed: 1 m / min
Laser light output format: Continuous Laser light average power density: 2.0kW / Φ20mm

(Measurement of surface roughness)
By image analysis using a three-dimensional photo measurement system (Kurabo Co., Ltd., Claves), the uneven height on the surface of the sprayed material layer was quantified, and the arithmetic average surface roughness Ra defined in JISB0601 was calculated. The arithmetic average roughness Ra is extracted from the roughness curve by a reference length in the direction of the average line, the X-axis is taken in the direction of the average line of the extracted portion, and the Y-axis is taken in the direction of the vertical magnification. Is expressed as y = f (x), the absolute value of deviation from the average line to the roughness curve is summed and averaged, that is, a value obtained by the following equation. L in the formula is a reference length, and L = 100 mm.

(Measurement of carbon adhesion strength)
A refractory brick was placed with the sprayed material layer as the upper surface, and a cylindrical ceramic having an inner diameter of 15 mm and a height of 35 mm was placed on the sprayed material layer. Next, the cylindrical ceramic was filled with coal tar and then fired at 1000 ° C. for 3 hours. After firing, the refractory brick was vertically placed and fixed so that the cylindrical ceramic was in a horizontal state, and the peripheral surface of the cylindrical ceramic was pressurized from above. The maximum pressure measured at this time was defined as carbon adhesion strength.

(Abrasion resistance test)
In a furnace at 800 to 820 ° C., the refractory brick was fixed so that the sprayed material layer was in the vertical orientation, and 3 kg of electrolytic alumina having an average particle size of about 1 mm was sprayed from the nozzle toward the sprayed material layer. Other test conditions are a nozzle diameter of 7 mm, a distance between the nozzle and the sprayed material layer of 10 mm, an air flow rate for blowing electrolytic alumina of 23 Nm ³ / hr, and an air pressure of 0.5 MPa. In this test, the wear volume calculated by the following equation was used as an evaluation standard for wear resistance.
Wear volume (cm ³ ) = ((mass before test) − (mass after test)) / bulk specific gravity

  Further, in order to compare the effects of the thermal spray material irradiated with the laser beam, the surface of the thermal spray material layer was treated by changing the laser beam irradiation to burner flame heating. At this time, the surface of the thermal spray material layer was heated with a burner flame at 1400, 1700, or 1900 ° C. for 10 seconds using a gas welding burner using LPG. Then, surface roughness measurement, carbon adhesion strength measurement, and wear resistance test were performed on the thermal spray material layer heated by the burner flame.

  Table 1 shows the results of surface roughness measurement, carbon adhesion strength, and wear resistance. Table 1 also shows the results when the surface of the thermal spray material layer was not subjected to laser irradiation or burner flame heating.

  From the results in Table 1, the following can be confirmed. The sprayed material layer that has been treated with the burner flame is improved in surface roughness as the burner flame temperature is increased, but on the other hand, the wear volume is increased (wear resistance is deteriorated). On the other hand, the thermal spray material layer that has been treated with laser light is excellent in both surface roughness and wear resistance, and in carbon adhesion strength.

It is a figure for demonstrating the repair method which concerns on embodiment of this invention.

Explanation of symbols

1 Carbonization chamber wall 2 Defect 3 Sprayed material layer 4 Laser beam

Claims (2)

  A method for repairing a refractory wall, comprising forming a thermal spray material layer on a defect portion of the refractory wall and irradiating the surface of the thermal spray material layer with laser light. The method for repairing a refractory wall according to claim 1, wherein the refractory wall is a wall of a coke oven carbonization chamber.

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