Heat insulation protection member, its manufacturing method, construction method, furnace interior member, and heating furnace

Abstract

This heat insulating protective member comprising an inorganic fiber formed body having a hollow cylindrical shape or a divided hollow cylindrical shape is characterized in that the inorganic fiber formed body has an inner peripheral surface (c) forming a hollow, and an outer peripheral surface (a) forming an outer periphery, and the bulk density increases toward the outer peripheral surface (c).

Description

[Technical field]

[0001] The present invention relates to a heat insulating protective member to be attached to a skid pipe or the like in a heating furnace, a method for installing the same, and a heating furnace. [Background technology]

[0002] 2. Description of the Related Art Inorganic fiber assemblies and inorganic fiber molded articles that are highly resistant to thermal shock are used as protective members for skid pipes in heating furnaces in the steel industry (Patent Documents 1 to 3).

[0003] Patent Document 1 describes covering a skid pipe with a ring-shaped heat insulating material made of ceramic fibers produced by punching. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP2004-43918A [Patent Document 2] WO2016 / 076258A1 [Patent Document 3] WO2017 / 195606A1 Summary of the Invention [Problem to be solved by the invention]

[0005] However, punching is not economical, and the heat insulating material of Patent Document 1 is not practical. In addition, conventional ring-shaped heat insulating materials made of inorganic fibers do not have sufficient physical strength and can become brittle due to scale corrosion inside the furnace or rapid temperature changes due to temperature increases and decreases. Therefore, if people frequently move around inside the furnace during regular repairs, there is a risk that they will be damaged by contact. The present invention aims to provide a heat insulating protective member that is made of an inorganic fiber molded body that has cushioning properties and excellent workability, and has excellent physical strength, a manufacturing method and an installation method for this heat insulating protective member, an inner furnace member, and a heating furnace. [Means for solving the problem]

[0006] The present invention proposes an insulating protective member that is less likely to be damaged by contact, by focusing on improving the rigidity on the outer peripheral surface side without compromising the cushioning properties on the inner peripheral surface side of a hollow cylindrical insulating protective member used in high-temperature environments such as inside a furnace.

[0007] The present invention relates to the following.

[0008] [1] A thermal insulation protective member comprising an inorganic fiber molding having a hollow cylindrical shape or a divided shape of a hollow cylinder, the inorganic fiber molding having an inner peripheral surface (c) facing the hollow space and an outer peripheral surface (a) constituting the outer periphery, the inorganic fiber molding having a bulk density that is higher on the outer peripheral surface (a) side.

[0009] [2] The insulating protective member described in [1], wherein the midpoint between the outer peripheral surface (a) and the inner peripheral surface (c) of the inorganic fiber molding is defined as an intermediate portion (b), and the bulk density (Da) at the outer peripheral surface, the bulk density (Db) at the intermediate portion, and the bulk density (Dc) at the inner peripheral surface satisfy the relationship Da>Db>Dc.

[0010] [3] The thermal insulation protective member according to [1] or [2], wherein the inorganic fiber molding contains an inorganic binder, and the content of the inorganic binder increases toward the outer peripheral surface (a).

[0011] [4] The thermal insulation protective member according to any one of [1] to [3], wherein the inorganic fiber molded body is an inorganic fiber molded sintered body containing inorganic binder particles that bind the inorganic fibers together, and the inorganic binder particles are present in greater amounts toward the outer peripheral surface (a).

[0012] [5] The heat insulating protective member according to any one of [1] to [4], characterized in that the heat insulating protective member has a divided shape of a hollow cylinder, and the divided surface is an oblique cut surface.

[0013] [6] The heat insulating protective member according to any one of [1] to [5], wherein an end surface of the heat insulating protective member is provided with a hole for inserting a pin.

[0014] [7] An internal furnace component having a thermal insulation protection member according to any one of [1] to [6] attached to its outer surface.

[0015] [8] The insulation protection member is an insulation protection member of [6], and a pin is inserted into both of the holes of adjacent insulation protection members whose end faces are butted together.

[0016] [9] The furnace interior component according to [7] or [8], having a sheet-like inorganic fiber covering the thermal insulation protection member attached to the furnace interior component.

[0017]

[10] A method for installing a thermal insulation protective member, comprising the step of attaching any one of the thermal insulation protective members [1] to [6] to an outer surface of an internal furnace member.

[0018]

[11] The insulation protection member is the insulation protection member of [6], and the construction method of the insulation protection member of

[10] comprises inserting a pin into both of the holes of adjacent insulation protection members whose end faces are butted together.

[0019]

[12] A method for installing an insulating protective member according to

[10] or

[11] , comprising the step of filling the gap between the end face of the insulating protective member and the furnace interior member with inorganic fiber filler after installing the insulating protective member.

[0020]

[13] The method for installing a heat insulating protective member according to any one of

[10] to

[12] , further comprising the step of covering the heat insulating protective member with a sheet-like inorganic fiber after mounting the heat insulating protective member.

[0021]

[14] A heating furnace having an internal furnace member according to any one of [6] to [9].

[0022]

[15] A heating furnace according to

[14] , wherein the furnace interior component is a skid post.

[0023]

[16] A method for producing a heat insulating protective member according to any one of [1] to [6], comprising the steps of: laminating an inorganic fiber blanket between an inner mold and an outer mold to form a hollow cylindrical molded body; then immersing the hollow cylindrical molded body in an inorganic binder-containing liquid; lifting the hollow cylindrical molded body out of the inorganic binder-containing liquid and sucking it in a direction from the inner circumferential surface side to the outer circumferential surface side of the hollow cylindrical molded body to drain the inorganic binder-containing liquid; and drying the hollow cylindrical molded body.

[0024]

[17] A method for producing a heat insulating protective member according to

[16] , comprising a step of pressing and compressing the hollow cylindrical molded body of the laminated inorganic fiber blanket.

[0025]

[18] A method for manufacturing an insulating protective member described in

[16] or

[17] , characterized in that the inner and outer molds are placed in a suction dehydration case, and the inner and outer molds have a plurality of holes penetrating in a direction perpendicular to the axial line of the inner mold. Effect of the Invention

[0026] The heat insulating protective member of the present invention is impregnated with an inorganic binder, and contains more inorganic binder on the outer peripheral side than on the inner peripheral side, so that the bulk density on the outer peripheral side is higher. As a result, the inorganic binder enhances the integral bonding of the heat insulating protective member, and improves the rigidity of the outer peripheral side without impairing the cushioning property of the inner peripheral side.

[0027] The heat insulating protective member of the present invention is an inorganic fiber molded sintered body, in which inorganic binder particles, which are a sintered product of an inorganic binder, are present in greater amounts on the outer peripheral surface than on the inner peripheral surface, and the bulk density is higher on the outer peripheral surface side. Therefore, the inorganic binder particles enhance the integral bonding of the heat insulating protective member, and the rigidity of the outer peripheral surface is improved without impairing the cushioning properties of the inner peripheral surface. [Brief description of the drawings]

[0028] [Figure 1] 4A to 4C are perspective views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Diagram 2]4A to 4C are cross-sectional views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Diagram 3] 4A to 4C are cross-sectional views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Figure 4] 4A to 4C are cross-sectional views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Diagram 5] 4A to 4C are cross-sectional views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Figure 6] 4A to 4C are cross-sectional views showing a method for manufacturing a heat insulating protective member according to an embodiment. [Figure 7] 1 is a perspective view showing an example of a heat insulating protective member according to an embodiment; [Figure 8] 1 is a perspective view showing an example of a heat insulating protective member according to an embodiment; [Figure 9] FIG. 2 is a perspective view showing an example of a furnace internal component. [Figure 10] 1 is a perspective view showing a method for installing a heat insulating protective member according to an embodiment. [Figure 11] 1 is a perspective view showing a method for installing a heat insulating protective member according to an embodiment. [Figure 12] FIG. 12a is a perspective view showing a method for installing a heat insulating protective member according to an embodiment, and FIG. 12b is a cross-sectional view taken along line XIb-XIb in FIG. 12a. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, an embodiment will be described with reference to Fig. 1 to Fig. 12b. In the following description, the heat insulating protection member is attached to the skid pipe, but it may be attached to other in-furnace members such as the skid beam.

[0030] In addition, the description "a to b" indicating a numerical range means "a or more and b or less" unless otherwise specified, and also includes the meanings of "preferably greater than a" and "preferably smaller than b."

[0031] Furthermore, even if the upper and lower limits of the numerical ranges in this specification are slightly outside the numerical ranges specified by the present invention, they are included in the equivalent range of the present invention as long as they have the same action and effect as those within the numerical range.

[0032] The skid pipe 1 on which the thermal insulation protective member is applied is a pipe made of heat-resistant steel as shown in Fig. 9, and stands upright from the hearth G of the heat treatment furnace. A skid beam 2 is installed so as to be supported by a plurality of skid pipes 1. A fireproof coating 3 made of fireproof castable is applied to the upper part of the skid pipe 1. In the present invention, the thermal insulation protective member is applied to the skid pipe 1 below the fireproof coating 3.

[0033] The skid pipe 1 is provided with a plurality of anchors (not shown) spaced apart in the height direction.

[0034] Since the cross section of the skid pipe 1 may not be a perfect circle, it is preferable to cover the outer circumferential surface of the skid pipe 1 with a base layer 5 (see FIG. 12b) prior to application of the heat insulating protective member. This improves the adhesion between the outer circumferential surface and the heat insulating protective member 10, and enables a higher heat insulating effect to be achieved. The base layer 5 is made of inorganic fibers, castable refractories, etc.

[0035] In the present invention, a plurality of heat insulating protection members 10 made of needle blankets of inorganic fibers (alumina / silica-based fibers in this embodiment) are attached to the skid pipe 1 in multiple layers, one above the other.

[0036] As shown in FIG. 8, the heat insulating protective member 10 has a substantially halved hollow cylindrical shape, and the pair of heat insulating protective members 10 are attached by butting against each other so as to sandwich the skid pipe 1.

[0037] As shown in FIG. 10, a pair of heat insulating protective members 10 are attached to the lowest part of the skid pipe 1, and then a refractory pin 12 (made of alumina in this embodiment) is inserted into a hole 11 in the upper end surface of the heat insulating protective member 10 and raised up.

[0038] Next, a pair of heat insulating protective members 10 in the second tier from the bottom are attached to the skid pipe 1. At this time, the pins 12 protruding from the lower heat insulating protective member 10 are inserted into the holes 11 in the lower end surface of the second tier heat insulating protective member 10. Also, the pins 12 are inserted into the holes 11 in the upper end surface of the second tier heat insulating protective member 10 and stand them up.

[0039] After the second stage of the heat insulating protective member 10 is attached, the third stage and subsequent stages of the heat insulating protective member 10 are attached to the skid pipe 1 in the same manner.

[0040] In order to prevent gaps caused by the butt surfaces of the heat insulating protective members 10 that are butted together to sandwich the skid pipe 1 from continuing between adjacent heat insulating protective members 10 in the vertical direction, it is preferable to make the orientation of the heat insulating protective members 10 different for each row.

[0041] As shown in FIG. 11, after the topmost (third in FIG. 11) heat insulating protective member 10 is attached to the skid pipe 1, a filler 13 made of a needle blanket of inorganic fiber (alumina / silica-based fiber in this embodiment) is pushed between the upper end surface of the topmost heat insulating protective member 10 and the fire-resistant coating 3.

[0042] A paste-like heat-resistant adhesive composition may be applied to the butting surfaces of the heat insulation protective members 10 or to the inner peripheral surface of the heat insulation protective members 10. A suitable heat-resistant adhesive composition is one in which pulverized inorganic fibers and fireclay such as kaolinite are kneaded with water.

[0043] After filling the filler 13 as described above, the blanket 15 in a wet state impregnated with an inorganic binder is wrapped around the outer periphery of each heat insulating protective member 10 as shown in Fig. 12a and 12b, and the construction is completed. The blanket 15 in a wet state impregnated with an inorganic binder is dried and fired through a temperature increase and heating process after the start of operation of the heating furnace, and becomes a blanket containing an oxide-based refractory composition.

[0044] By wrapping the blanket 15, it is possible to efficiently prevent hot air from entering the heat insulating protective member attached to the skid pipe 1.

[0045] Next, a method for manufacturing the heat insulating protective member 10 will be described with reference to FIGS.

[0046] 1 and 2, an inner mold 20 is prepared that has a bottomed, hollow cylindrical shape and has a bottom surface portion 21 and a peripheral side portion 22. The peripheral side portion 22 is provided with a large number of holes 23 that penetrate from the inner peripheral surface to the outer peripheral surface. The bottom surface portion 21 has no holes.

[0047] After wrapping a release sheet (not shown) made of a glass fiber sheet or the like around the outer periphery of the inner mold 20, a needle blanket 30 made of inorganic fibers (alumina fibers in this embodiment) is laminated and filled between the inner mold and the outer mold. The size and shape of the needle blanket are not particularly limited, but it is preferable to process it according to the size of the heat insulating protective member (the length from the inner periphery side to the outer periphery side and the length of the inner periphery). For example, it is preferable to use an inorganic fiber needle blanket processed to a length equivalent to the periphery of the inner mold 20. In addition, it is preferable to process the inorganic fiber needle blanket to a width equivalent to the length from the inner periphery side to the outer periphery side in the cross-sectional shape of the hollow cylinder of the intended heat insulating protective member.

[0048] In one embodiment, as shown in FIG. 2, a first outer mold 40 is positioned to surround the inner mold 20, and the needle blanket 30 is filled by pushing it between the side periphery 42 of the outer mold 40 and the side periphery 22 of the inner mold 20.

[0049] The outer mold 40 is a bottomed hollow cylinder having a bottom surface portion 41 and a peripheral side portion 42. The inner mold 20 is coaxially arranged in the outer mold 40 such that the bottom surface portion 21 overlaps the bottom surface portion 41. The peripheral side portion 42 is provided with a large number of holes 43 penetrating therethrough. A flange 44 is provided at the upper end of the peripheral side portion 42.

[0050] It is preferable that the outer mold 40 is shorter in height than the inner mold 20. In this embodiment, the height of the outer mold 40 is approximately half that of the inner mold 20. After filling the space between the inner mold and the outer mold with a plurality of needle blankets 30 up to near the upper end of the outer mold 40, a second outer mold 50 is placed above the outer mold 40. The second outer mold 50 is hollow cylindrical and has the same diameter as the outer mold 40. The outer mold 50 also has a number of holes 53. The outer mold 50 has flanges 54, 55 at its lower and upper ends, respectively.

[0051] The outer dies 40, 50 are integrated by overlapping their flanges 44, 54 and connecting them with bolts.

[0052] As shown in Fig. 3, the needle blanket 30 is filled between the inner mold 20 and the outer mold 50 in the same manner as above between the second outer mold 50 and the inner mold 20. After the needle blanket 30 is filled up to the top as shown in Fig. 3, the ring plate 61 of the pressing jig 60 is pressed between the inner mold 20 and the second outer mold 50 as shown in Fig. 4, and the needle blanket 30 wound between the inner mold 20 and the outer molds 40, 50 is compressed to form a hollow cylindrical molded body 30A in which the needle blanket 30 is integrally formed in a continuous manner. This compression may be performed by screwing in a bolt 62, which will be described next.

[0053] The jig 60 has a ring plate 61 and a cover plate 63. An opening 64 is provided in the center of the cover plate 63. The cover plate 63 and the upper flange 55 of the second outer die 50 are connected with bolts (not shown) or the like, and the ring plate 61 is pressed with bolts 62 to maintain the compressed state of the hollow cylindrical molded body 30A.

[0054] Then, as shown in FIG. 5, the entire integrated body 80 of the inner mold 20, the hollow cylindrical molded body 30A, the outer molds 40, 50, and the jig 60 is immersed in the inorganic binder-containing liquid L in the tank 81, and the inorganic binder-containing liquid is sufficiently impregnated into the hollow cylindrical molded body 30A.

[0055] Thereafter, the integrated body 80 is lifted up from the inorganic binder-containing liquid L and placed in a suction dehydration case 70 as shown in Fig. 6. The peripheral portion of the cover plate 63 is placed on the flange at the upper end of the case 70 with a packing 74 interposed therebetween.

[0056] The inside of the case 70 is sucked through the suction port 75 at the bottom of the case 70. As a result, the inorganic binder-containing liquid L that had accumulated in the inner mold 20 is sucked out of the outer molds 40, 50 through the hole 23 of the inner mold 20, the hollow cylindrical molded body 30A, and the holes 43, 53 of the outer molds 40, 50, and is discharged through the suction port 75. At this time, air flows into the inner mold 20 through the opening 64.

[0057] After suction is performed for a predetermined time, the opening 64 is connected to a hot air source (not shown) to continue suction, whereby hot air passes through the hollow cylindrical molded body 30A to dry the hollow cylindrical molded body 30A.

[0058] After the hollow cylindrical molded body 30A has dried, the integrated body 80 consisting of the inner mold 20, hollow cylindrical molded body 30A, outer molds 40, 50 and jig 60 is removed from the case 70, the jig 60 and outer molds 40, 50 are removed, and then the inner mold 20 is removed from within the hollow cylindrical molded body 30A to obtain the hollow cylindrical molded body 30A shown in Figure 7.

[0059] Holes 11 are drilled in the upper and lower end faces of this hollow cylindrical molded body 30A. The drilling method is not particularly limited, but for example, it is preferable to use a cork borer from the viewpoint of dimensional accuracy.

[0060] 8, the hollow cylindrical molded body 30A is cut in a direction parallel to the cylinder axis to form a half-split hollow cylindrical heat insulating protective member 10. The cut surface 10c is oblique to the diameter direction of the hollow cylindrical molded body 30A.

[0061] The heat insulating protective member 10 thus manufactured is generally shipped in the manufactured form and attached to a furnace internal structure such as a skid pipe.

[0062] However, the heat insulating and protective member produced as described above may be further fired and allowed to cool before being shipped as a heat insulating and protective member product.

[0063] When a pair of heat insulating protective members 10 are combined to form a hollow cylindrical shape, the length of the cylinder in the axial direction is preferably 100 to 600 mm, particularly 150 to 400 mm, and the thickness is preferably 20 to 100 mm, particularly 30 to 80 mm.

[0064] According to the manufacturing method of the heat insulation protection member 10, the inorganic binder is impregnated into the entire heat insulation protection member 10 as shown in Figs. 5 and 6. In this way, by impregnating the entire heat insulation protection member with the inorganic binder, it is possible to obtain an inorganic fiber molded body that is less likely to cause delamination of the heat insulation protection member, i.e., the inorganic binder-containing liquid is sucked from the inner mold 20 toward the outer molds 40 and 50, so that the content of the inorganic binder is higher toward the outer peripheral surface side in the hollow cylindrical molded body 30A of Fig. 7. When the heat insulation protection member 10 is fired, the inorganic binder forms inorganic binder particles to bond the fibers together. Therefore, the higher the content of the inorganic binder, the greater the amount of inorganic binder particles attached to the heat insulation protection member 10 after firing, and the stiffness of the outer peripheral surface of the heat insulation protection member 10, i.e., the physical strength, is higher.

[0065] However, if the content of the inorganic binder is high, the weight of the heat insulation protective member 10 increases. In this embodiment, since the content of the inorganic binder is high on the outer peripheral surface side of the heat insulation protective member 10, the strength and rigidity of the outer peripheral surface side of the heat insulation protective member 10 are high. Also, since the content of the inorganic binder is low on the inner peripheral surface side of the heat insulation protective member 10, the bulk density of the heat insulation protective member 10 is low.

[0066] [Materials for heat insulation protection member 10, etc.] The needle blanket 30 for manufacturing the heat insulating protective member 10 is not particularly limited as long as it is an inorganic fiber blanket, but is preferably an inorganic fiber needle blanket described below.

[0067] The needle blanket is preferably a fiber aggregate of inorganic fibers that does not substantially contain fibers having a fiber diameter of 3 μm or less, which has been subjected to a needling treatment. By using such a needle blanket, the wind corrosion resistance of the thermal insulation protective member for a skid pipe of the present invention can be improved.

[0068] <Inorganic fibers> The inorganic fibers constituting the needle blanket are not particularly limited, and examples thereof include single or composite fibers such as silica, alumina / silica, and zirconia, spinel, titania, and calcia containing these. In terms of heat resistance, fiber strength (toughness), and safety, alumina / silica-based fibers, and in particular polycrystalline alumina / silica-based fibers, are particularly preferred.

[0069] The alumina / silica composition ratio (mass ratio) of the alumina / silica fiber is preferably in the range called a mullite composition or high alumina composition of 65-98 / 35-2, more preferably 70-95 / 30-5, and particularly preferably 70-74 / 30-26.

[0070] In the present invention, it is preferable that 80 mass % or more, preferably 90 mass % or more, and particularly preferably the entire amount of the inorganic fibers is polycrystalline alumina / silica-based fibers having the above-mentioned mullite composition. In addition, the molar ratio of Ca to Al in the inorganic fibers (Ca / Al) is preferably 0.03 or less, and it is particularly preferable that the inorganic fibers do not contain Ca.

[0071] The inorganic fibers preferably do not substantially contain fibers having a fiber diameter of 3 μm or less. Here, "substantially not containing fibers having a fiber diameter of 3 μm or less" means that the amount of fibers having a fiber diameter of 3 μm or less is 0.1 mass % or less of the total fiber weight.

[0072] The inorganic fibers preferably have an average fiber diameter of 5 to 7 μm. If the average fiber diameter of the inorganic fibers is too large, the resilience and toughness of the fiber assembly will be lost, whereas if the average fiber diameter of the inorganic fibers is too small, the amount of dust suspended in the air will increase, and the probability of containing fibers with a fiber diameter of 3 μm or less will increase.

[0073] <Needle blanket manufacturing method> An inorganic fiber aggregate having the above-mentioned preferred average fiber diameter and substantially free of fibers with a fiber diameter of 3 μm or less can be obtained in the production of an inorganic fiber aggregate by the sol-gel method, by controlling the viscosity of the spinning solution, controlling the air flow used in the spinning nozzle, controlling the drying of the drawn yarn, and controlling needling, etc.

[0074] The needle blanket is manufactured by a conventional method, for example as described in JP 2014-5173 A, through a process of obtaining an aggregate of inorganic fiber precursors by a sol-gel method, a process of subjecting the obtained aggregate of inorganic fiber precursors to a needling process, and a firing process of firing the needled aggregate of inorganic fiber precursors to form an inorganic fiber aggregate.

[0075] <Needle mark density, bulk density and thickness of needle blanket> The density of needle marks on the needle blanket is 2 to 200 marks / cm 2 , especially 2 to 150 shots / cm 2 , especially 2 to 100 strokes / cm 2 , especially 2 to 50 shots / cm 2 If the density of needle marks is too low, problems such as a decrease in uniformity in the thickness of the needle blanket and a decrease in thermal shock resistance may occur, whereas if the density is too high, the fibers may be damaged and may easily scatter after firing.

[0076] The bulk density of the needle blanket is 50 to 200 kg / m 3 (0.05~0.2g / cm 3 ), and 80 to 150 kg / m 3 (0.08~0.15g / cm 3 If the bulk density is too low, the inorganic fiber molded article will be brittle, whereas if the bulk density is too high, the mass of the inorganic fiber molded article will increase and the resilience will be lost, resulting in a molded article with low toughness.

[0077] The surface density of the needle blanket is 500 to 4000 g / m 2, especially 600~3800g / m 2 , especially 1000~3500g / m 2 If the surface density of the needle blanket is too small, the fiber amount is small and only a very thin molded product is obtained, which reduces its usefulness as a heat-insulating inorganic fiber molded product, whereas if the surface density is too large, the fiber amount is too large, making it difficult to control the thickness by needling treatment.

[0078] The thickness (vertical thickness in FIG. 1) of the needle blanket 30 is preferably 3 to 30 mm, particularly preferably 5 to 15 mm, and the width is preferably 20 to 100 mm, particularly preferably 30 to 80 mm.

[0079] [Inorganic binder] The inorganic binder to be impregnated into the needle blanket is not particularly limited, and may be an inorganic sol, a metal salt, or a mixture thereof, which forms an oxide after firing. Specific examples will be described below, but the present invention is not limited thereto.

[0080] Examples of inorganic sols include alumina sol, zirconia sol, titania sol, magnesia sol, and calcia sol. Examples of metal salts include organic acid salts of the above metals, such as formic acid, acetic acid, citric acid, oxalic acid, benzoic acid, and malic acid, and mineral acid salts, such as nitric acid. Among these, alumina sol is preferred because its thermal expansion coefficient is close to that of the inorganic fiber aggregate. A plurality of inorganic sols may be used as the inorganic binder.

[0081] The concentration of the inorganic binder-containing liquid is preferably 6 to 14% by weight, more preferably 8 to 11% by weight, in terms of solid content. The viscosity of the inorganic binder-containing liquid is preferably adjusted to 5 to 200 cp.

[0082] [Configuration of heat insulating protective member 10] The heat insulating protective member of the present invention is made of an inorganic fiber molded body having an inner peripheral surface (c) constituting a hollow space and an outer peripheral surface (a) constituting an outer periphery, and the bulk density is higher toward the outer peripheral surface (a). Here, a method for measuring the bulk density will be described.

[0083] That is, in the cross section connecting the inner peripheral surface (c) and the outer peripheral surface (a), 1 / 3 of the area on the inner peripheral surface (c) side is the inner peripheral region, 1 / 3 of the area on the outer peripheral surface (a) side is the outer peripheral region, and 1 / 3 of the area between the outer peripheral region and the inner peripheral region is the intermediate region. The intermediate point between the outer peripheral surface (a) and the inner peripheral surface (c) of the inorganic fiber molded body is the intermediate part (b). In the present invention, the measurement positions of the bulk density (C), inorganic binder attachment amount (B), etc. of each region are as follows. For example, all of the inorganic fiber molded bodies constituting the heat insulating protective member, or inorganic fiber molded bodies of any size cut out so as to have a cross section in a direction perpendicular to the hollow axis of the heat insulating protective member, are divided into three in the cross section, and the outer peripheral region, intermediate region, and inner peripheral region are defined. The bulk density at the inner surface (Dc) is measured by measuring the bulk density of the inner region (e.g., within 12 mm from the inner surface), the bulk density at the outer surface (Da) is measured by measuring the bulk density of the outer region (e.g., within 12 mm from the outer surface), and the bulk density at the intermediate portion (Db) is measured by measuring the bulk density in the intermediate region.

[0084] In the present invention, "the bulk density is higher toward the outer peripheral surface (a)" means that the bulk density is higher on the outer peripheral surface side than on the inner peripheral surface side, and it is not essential that the bulk density changes continuously from the inside to the outside. Here, the "inner peripheral surface side" refers to a portion relatively closer to the inner peripheral surface (c) than the outer peripheral surface (a), and the "outer peripheral surface side" refers to a portion relatively closer to the outer peripheral surface (a) than the inner peripheral surface (c).

[0085] Therefore, for example, the bulk density value may increase relatively rapidly from the inner circumferential surface (c) to the intermediate portion (b) and increase gradually from the intermediate portion (b) to the outer circumferential surface (a). Alternatively, the bulk density may be constant from the inner circumferential surface (c) to the intermediate portion (b) and increase from the intermediate portion to the outer circumferential surface (a). Alternatively, there may be a spot region with high bulk density in the intermediate portion (b), and the bulk density value may decrease once toward the outer circumferential surface (a) and then increase.

[0086] However, from the viewpoint of significantly improving the physical strength due to contact, it is preferable that the bulk density of the inorganic fiber molding constituting the thermal insulation protective member of the present invention satisfies the relationship Da>Db>Dc, and it is even more preferable that the bulk density continuously increases from the inner surface (c) to the outer surface (a).

[0087] The bulk density (Dc) on the inner circumferential surface is lower than the bulk density (Da) on the outer circumferential surface, and is preferably about 50 to 99 mass %, more preferably 60 to 95 mass %, and particularly preferably about 70 to 90 mass %.

[0088] The bulk density (Db) in the intermediate portion is equal to or less than the bulk density (Da) in the outer peripheral surface and equal to or more than the bulk density (Dc) in the inner peripheral surface. The bulk density (Db) in the intermediate portion is preferably 75 to 99 mass%, more preferably 80 to 98 mass%, and particularly preferably 85 to 97 mass% of the bulk density (Da) in the outer peripheral surface. The bulk density (kg / m 3 ) can be calculated by dividing the weight by the volume.

[0089] In the heat insulating protective member of the present invention, the amount of the inorganic binder (adhered amount as solid content) is such that the closer to the outer peripheral surface (a), the greater the content of the inorganic binder. That is, it is preferable that the binder adhering amount (Ba) on the outer peripheral surface, the binder adhering amount (Bb) on the middle portion, and the binder adhering amount (Bc) on the inner peripheral surface satisfy the relationship Ba>Bb>Bc.

[0090] The amount of inorganic binder attached (Bc) on the inner peripheral surface is less than the amount of binder attached (Ba) on the outer peripheral surface, but is preferably about 0.1 to 50 mass%, more preferably about 0.5 to 30 mass%, and particularly preferably about 1.0 to 20 mass%. The amount of binder attached (Bb) on the middle portion is less than the amount of binder attached (Ba) on the outer peripheral surface and is greater than or equal to the amount of binder attached (Bc) on the inner peripheral surface. The amount of binder attached (Bb) on the middle portion is preferably about 10 to 95 mass%, more preferably about 20 to 90 mass%, and particularly preferably about 30 to 80 mass% of the amount of binder attached (Ba) on the outer peripheral surface.

[0091] The binder coating amount (Ba) in the outer peripheral region of the heat insulating protective member 10 of the present invention is preferably an oxide (e.g., Al 2 O 3 The amount of the inorganic fiber (calculated as a carbon fiber) is preferably 2 to 70 parts by mass, and more preferably 2 to 50 parts by mass, per 100 parts by mass of the inorganic fibers.

[0092] In addition, the binder adhesion amount (Bc) in the inner peripheral region of the heat insulating protective member 10 of the present invention is preferably an oxide (e.g., Al 2 O 3 The converted amount is 0.5 to 40 parts by mass, and more preferably 0.5 to 40 parts by mass, per 100 parts by mass of the inorganic fibers.

[0093] The binder coverage (Bb) in the intermediate region of the thermal insulation protective member 10 of the present invention is preferably an oxide (e.g., Al 2 O 3 The converted amount is preferably 2 to 55 parts by mass, and more preferably 2 to 35 parts by mass, per 100 parts by mass of the inorganic fibers.

[0094] The amount of inorganic binder attached (in terms of oxide) in the entire thermal insulation protective member is preferably 5 to 40 parts by mass, particularly 8 to 30 parts by mass, per 100 parts by mass of the inorganic fibers in the entire thermal insulation protective member.

[0095] In one embodiment, the heat insulation protection member of the present invention is an inorganic fiber molded body (impregnated with an inorganic binder-containing liquid, dried, and adhered) containing inorganic binder particles that bind inorganic fibers together. The inorganic fiber molded body has a greater amount of the inorganic binder particles adhered toward the outer peripheral surface (c). The inorganic binder particles are not particularly limited, but are preferably particles with an average particle diameter of 20 to 35 nm. It is believed that a large amount of inorganic binder particles contained in the inorganic fiber molded body increases the adhesiveness between the inorganic fibers that constitute the inorganic fiber molded body and fills the voids between the inorganic fibers, thereby improving the rigidity on the outer peripheral surface side.

[0096] In one embodiment, the heat insulating protective member of the present invention is an inorganic fiber molded fired body obtained by firing the above-mentioned inorganic fiber molded body. Even in this embodiment, the inorganic binder particles, which are the fired product of the inorganic binder, are present in greater amounts on the outer peripheral surface side than on the inner peripheral surface side of the inorganic fiber molded fired body, and the bulk density on the outer peripheral surface side is higher. Therefore, the inorganic binder particles increase the integral bonding property of the heat insulating protective member, and the rigidity on the outer peripheral surface side is improved. The inorganic binder particles can be observed, for example, using various microscopes.

[0097] In one embodiment, the heat insulating protective member of the present invention is made of an inorganic fiber molded body or a fired inorganic fiber molded body, and preferably has a bulk density that increases toward the bottom in the vertical direction.

[0098] In one embodiment, the heat insulating protective member of the present invention preferably has a single-layer structure in any cross section connecting the inner peripheral surface (c) and the outer peripheral surface (a).Specific examples of the single-layer structure include an inorganic fiber blanket wound once in a direction parallel to the hollow axis, and an inorganic fiber blanket laminated in a direction perpendicular to the hollow axis.

[0099] The heat insulating protective member of the present invention is preferably composed of inorganic fiber blankets laminated in the axial direction of the hollow space.

[0100] [Furnace interior materials] The furnace interior member of the present invention is a furnace interior member having the above-mentioned heat insulating protective member attached to its outer surface. The furnace interior member is not particularly limited, but is preferably a member having a curved surface, particularly a cylindrical surface. For example, a skid post (a skid pipe to which the heat insulating protective member of the present invention is attached) or a skid beam. Among them, a skid post is preferable because of the effect of improving the rigidity of the outer peripheral surface side in the present invention.

[0101] In one embodiment of the furnace interior member of the present invention, a wet blanket 15 with an inorganic binder attached thereto is wound around the outer periphery of the heat insulation protection member 10, and then construction is performed. The wet blanket 15 with the inorganic binder attached thereto is dried and fired through a temperature increase and heating process after the start of operation of the heating furnace, and becomes a blanket containing an oxide-based refractory composition. By winding the blanket 15, it is possible to efficiently prevent hot air from entering the heat insulation protection member attached to the skid pipe 1, which is preferable. As the blanket 15 with the inorganic binder attached in a wet state, it is preferable to impregnate the above-mentioned inorganic fiber needle blanket having a thickness of about 10 to 30 mm with the above-mentioned inorganic binder in a ratio of 2 to 50 parts by mass per 100 parts by mass of the inorganic fiber.

[0102] One embodiment of the furnace interior component of the present invention is a furnace interior component that uses an insulating protective member with a pin inserted into its end face, and is formed so that a pin can be inserted into both holes of adjacent insulating protective members whose end faces are butted together.

[0103] One embodiment of the furnace interior member of the present invention has a sheet-shaped inorganic fiber that covers the thermal insulation protection member of the present invention, which is attached to the furnace interior member. That is, an inorganic fiber layer may be formed on the outer side of the outer peripheral surface of the inorganic fiber molded body constituting the thermal insulation protection member of the present invention to form an outermost layer. In this case, the bulk density of the outermost layer may be equal to the bulk density (Da) of the outer peripheral portion, or may be smaller or larger than the bulk density (Da) of the outer peripheral portion. In addition, from the viewpoint of achieving the effect of improving the physical strength by contact, it is preferable that the bulk density of the outermost layer when the outermost layer is further formed is larger than the bulk density (Da) of the outer peripheral portion.

[0104] [Heating furnace] The heating furnace of the present invention has an inner furnace member to which the heat insulating protective member of the present invention is attached. EXAMPLES

[0105] In the following examples and comparative examples, the following ball drop test was carried out to evaluate the rigidity of the outer peripheral surface side of the thermal insulation protective member, assuming the physical strength as a furnace internal member.

[0106] [Definition of the drop ball test] The sample is processed to an area of ​​100 mm x 50 mm x 30 mm thickness, and a steel ball weighing 550 g is dropped onto the centre of the sample from a height of 60 cm. The difference in thickness of the centre of the sample before and after the test is taken as the dent depth.

[0107] [Example 1] A needle blanket (product name: Mitsubishi Chemical MAFTEC MLS-2, thickness 7.5 mm, bulk density 155 kg / m) made by accumulating and needling polycrystalline alumina / silica fibers containing 72% by mass of alumina and 28% by mass of silica, with an average fiber diameter of 5.5 μm and substantially no fibers with a fiber diameter of 3 μm or less. 3 ) was processed to a width of 40 mm and a length of 1150 mm to form a needle blanket 30.

[0108] 1 to 8, a 0.5 mm thick glass cloth (Tukoh Flow (registered trademark) G type fabric, manufactured by Chukoh Chemical Industry Co., Ltd.) was wound around the inner mold once as a release sheet. Then, needle blankets 30 were laminated in multiple layers between the inner mold 20 and the outer mold 40.

[0109] Next, the needle blanket was pressed in the stacking direction using a jig 60 to compress it, forming an integrated body 80. The integrated body 80 was immersed in an inorganic binder-containing liquid L made of an alumina sol (Nissan Chemical Co., Ltd. Alumina sol 200) with a solid content concentration of 9.6% by weight for 24 hours, and 17 kg was impregnated into the entire needle blanket.

[0110] After that, it was taken out of the liquid L, and the one-piece 80 was placed in the case 70 and deliquored for 15 minutes at a negative pressure of -13.5 to -8.5 kPa. After that, while continuing the suction, hot air at 100 to 150°C was introduced into the box for 4 hours to dry it. After drying, it was taken out of the case 70 and demolded. Then, the temperature was raised to 1000°C at a rate of 3°C / min and kept at that temperature for 3 hours to perform firing, which was designated as Example 1.

[0111] [Bulk density ratio] The inorganic fiber molded and fired body obtained in Example 1 was cut into three equal parts (12 × 13 × 45 mm) for the outer peripheral surface (a), the middle part (b), and the inner peripheral surface (c). The weight of each sample was measured and divided by the volume to obtain the bulk density (kg / m 3 ) was obtained. Three samples were prepared and the average value was calculated. The bulk density ratio was calculated based on the bulk density of the inner peripheral surface that showed the lowest bulk density among the obtained bulk densities. The results are shown in Table 1.

[0112] [Distribution of inorganic binder content (adhesion amount)] Similarly, the Al content of the inorganic binder on the outer surface (a), the middle part (b), and the inner surface (c) 2 O 3 The converted adhesion amount was measured. Three samples were prepared and the average adhesion amount for each was calculated. First, the inorganic binder adhesion amount (Ba) on the outer peripheral surface, the inorganic binder adhesion amount (Bb) on the middle portion, and the inorganic binder adhesion amount (Bc) on the inner peripheral surface were measured. Next, the adhesion amount (Bc) on the inner peripheral surface, which showed the lowest weight, was used as the reference value, and the adhesion amount on the inner peripheral surface (Bc) was subtracted from the adhesion amount on the outer peripheral surface (Ba) and the adhesion amount on the middle portion (Bb) to calculate the difference in the adhesion amount of the inorganic binder. The results are shown in Table 1.

[0113] [Comparative Example 1] A vacuum-formed hard ceramic fiber insulation material equivalent to the ring-shaped insulation material disclosed in JP 2004-043918 A was subjected to the same measurements as in Example 1. The results are shown in Table 1.

[0114] [Table 1]

[0115] [Consideration] The inorganic fiber molded sintered body of Example 1, which is a heat insulating protective member of the present invention, shows that the depth of breakage of a steel ball in a falling ball test is very shallow, and that the body has excellent physical strength. In other words, since the bulk density is higher toward the outer peripheral surface, it is considered that the physical strength assuming breakage due to contact is significantly improved. In addition, from the distribution of the amount of attached inorganic binder particles calculated from the weight measurement, it was found that in Example 1, the inorganic binder particles are attached in a large amount in a sloping manner from the inside to the outside.

[0116] In this way, the inorganic fiber molded sintered body of Example 1, in which the inorganic binder is selectively attached to the outer peripheral surface, has more inorganic binder particles attached to the outer peripheral surface side as an insulating protective member where strength is required, and fewer inorganic binder particles attached to the inner peripheral surface side where adhesion (cushioning properties) with the furnace interior components during construction is required. This is thought to reduce damage due to contact and provide stronger protection and fixation of the furnace interior components.

[0117] Furthermore, the inorganic fiber molded sintered body of Example 1 has a structure in which the inorganic fiber blanket is stacked and compressed in a direction approximately perpendicular to the contact direction with the falling ball, so that the impact of the falling ball can be dispersed at the stacking interfaces and dissipated between the layers, which is thought to have significantly improved physical strength.

[0118] In addition, it was confirmed by visual observation after the ball drop test that small cracks occurred between the layers of the inorganic fiber blanket in the lamination direction of the inorganic fiber blanket in the inorganic fiber molded fired body of Example 1. When this is installed as a heat insulating protective material for furnace internal components, it is compressed and pressed in the vertical direction of the lamination, which is thought to improve the physical strength and prevent cracks from occurring.

[0119] On the other hand, the inorganic fiber molded and fired body of Comparative Example 1 had many large cracks in various directions and was significantly pulverized. It is believed that the inorganic fiber molded and fired body of Comparative Example 1 was easily cracked and pulverized because bulk inorganic fibers (only collected fibers) were used as the raw material, and the fibers were not entangled with each other.

[0120] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention. This application is based on Japanese Patent Application No. 2019-133919 filed on July 19, 2019, the entirety of which is incorporated by reference. [Explanation of symbols]

[0121] 10. Thermal insulation protection materials 13. Stuffing 20 Inner mold 30 Needle Blanket 40,50 External mold 80 One Piece

Claims

1. A heat insulating protective member made of an inorganic fiber molded body having a hollow cylindrical shape or a divided hollow cylindrical shape, The inorganic fiber molded body has an inner peripheral surface (c) facing a hollow space and an outer peripheral surface (a) constituting an outer periphery, The inorganic fiber molded body is A heat insulating protective member for use in heating furnaces in the steel industry, characterized in that the bulk density increases toward the outer peripheral surface (a).

2. A middle point between the outer peripheral surface (a) and the inner peripheral surface (c) of the inorganic fiber molded body is defined as a middle portion (b), The bulk density (Da) at the outer peripheral surface, the bulk density (Db) at the intermediate portion, and the bulk density (Dc) at the inner peripheral surface are The heat insulating protective member according to claim 1 , wherein the relationship Da>Db>Dc is satisfied.

3. The inorganic fiber molded body contains an inorganic binder, 3. The heat insulating protective member according to claim 1, wherein the inorganic binder content is increased toward the outer peripheral surface (a).

4. The inorganic fiber molded body is an inorganic fiber molded fired body containing inorganic binder particles that bind inorganic fibers together, The heat insulating protective member according to any one of claims 1 to 3, wherein the inorganic binder particles are present in a greater amount toward the outer circumferential surface (a).

5. The heat insulating protection member has a divided shape of a hollow cylinder, 5. The heat insulating protective member according to claim 1, wherein the dividing surface is a cut surface obliquely cut with respect to the diametrical direction of the hollow cylinder.

6. The heat insulating protective member is a pair of heat insulating protective members each made of an inorganic fiber molded body having a divided shape of a hollow cylinder, The pair of heat insulating protective members have cut surfaces extending parallel to a cylinder axis line, The heat insulating protective member according to any one of claims 1 to 5, wherein the pair of heat insulating protective members are arranged in multiple vertical stages with the cut surfaces butted against each other, and the positions of the cut surfaces are shifted from one stage to the next.

7. A hole for inserting a pin is provided on an end surface of the heat insulating protection member, a plurality of holes are provided on each of the upper end surface and the lower end surface of the pair of heat insulation protective members, In the pair of vertically adjacent heat insulating protective members, The heat insulating protective member according to claim 6, wherein the holes provided in the lower end surfaces of the pair of heat insulating protective members located on the upper side face each other with the cut surface of the pair of heat insulating protective members located on the lower side sandwiched therebetween, and the holes provided in the upper end surfaces of the pair of heat insulating protective members located on the lower side face each other.

8. An inner furnace member of a heating furnace in the steel industry, the inner furnace member having the heat insulating protective member according to any one of claims 1 to 7 attached to its outer surface.

9. The insulating protective member is the insulating protective member of claim 7, and a pin is inserted into the hole of both of the insulating protective members adjacent to each other in the vertical direction where the lower end surface and the upper end surface are butted together.

10. 10. The furnace internal member according to claim 8, further comprising a sheet-shaped inorganic fiber covering the thermal insulation protection member attached to the furnace internal member.

11. A method for installing an insulating protective member, comprising the step of attaching an insulating protective member according to any one of claims 1 to 7 to the outer surface of an inner furnace member of a heating furnace in the steel industry.

12. The method for installing a heat insulating protective member according to claim 11, wherein the heat insulating protective member is the heat insulating protective member according to claim 7, and a pin is inserted into both of the holes of adjacent heat insulating protective members whose end faces are butted together.

13. 13. The method for installing a thermal insulation protective member according to claim 11 or 12, further comprising the step of filling a gap between an end face of the thermal insulation protective member and an inner furnace member with a filler of inorganic fibers after the thermal insulation protective member is installed.

14. The method for installing a heat insulating protective member according to any one of claims 11 to 13, further comprising the step of covering the heat insulating protective member with a sheet-like inorganic fiber after the heat insulating protective member is attached.

15. A heating furnace for the steel industry, comprising the furnace internal member according to any one of claims 8 to 10.

16. 16. The furnace of claim 15, wherein said internals are skid posts.

17. A method for producing a heat insulating protective member according to any one of claims 1 to 7, comprising the steps of: A step of laminating an inorganic fiber blanket between the inner mold and the outer mold to form a hollow cylindrical molded body; Thereafter, the hollow cylindrical molded body is immersed in an inorganic binder-containing liquid; The hollow cylindrical molded body is pulled out from the inorganic binder-containing liquid. a step of draining the inorganic binder-containing liquid by sucking in a direction from the inner peripheral surface side to the outer peripheral surface side of the hollow cylindrical molded body; and drying the hollow cylindrical molded body.

18. The method for producing a heat insulating protective member according to claim 17, further comprising a step of compressing and shrinking the hollow cylindrical molded body of the laminated inorganic fiber blankets.

19. The inner mold and the outer mold are disposed in a suction dehydration case, and 19. The method for manufacturing a heat insulating protective member according to claim 17 or 18, wherein the inner mold and the outer mold have a large number of holes passing through in a direction perpendicular to the axial center line of the inner mold.

Images