Regenerator for radiant tube burner and method of manufacturing the same

Abstract

To provide a heat storage body in which a plurality of honeycomb structures are continuously provided in an axial direction in which cells extend, and an increase in pressure loss is suppressed in gas circulation due to the fact that the positions of the cells in each of the honeycomb structures are shifted between the adjacent honeycomb structures.SOLUTION: In the heat storage body 1, a plurality of honeycomb structures 10 having a plurality of cells partitioned by partition walls extended in a single direction and arranged in a row are continuously arranged in the axial direction in which the cells are extended by making the S1 parts of end faces where the cells are opened face each other. The plurality of honeycomb structures 10 are integrated by an adhesive tape 21 attached to the side peripheral surface S2 of each of the adjacent honeycomb structures 10 so as to straddle the boundary of the adjacent honeycomb structures 10 in the axial direction in which the cells extend, and the adhesive tape 21 is made of an organic material that loses a tape shape when heated.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a regenerator for a regenerative radiant tube burner and a method for manufacturing the regenerator. [Background technology]

[0002] A radiant tube burner is a device that indirectly heats the material to be treated by radiating heat from a burner inside a metal or ceramic tube. Radiant tube burners can increase the temperature of the furnace atmosphere without affecting the furnace atmosphere. Radiant tube burners have open tubes at both ends, supplying combustion air from one end and discharging exhaust gas from the other. Radiant tube burners include those with straight, U-shaped, and W-shaped tubes. On the other hand, there are also so-called single-ended radiant tube burners, in which one end of the tube is closed inside the furnace and both an air inlet for introducing combustion air and an exhaust port for discharging exhaust gas are located at the open end.

[0003] Radiant tube burners also include regenerative burners. In regenerative radiant tube burners, the direction of gas flow is switched at predetermined time intervals so that exhaust gas heated to a high temperature by burner combustion and newly supplied gas for burner combustion alternately come into contact with the heat storage body. The heat of the exhaust gas is recovered by the heat storage body, and the recovered heat is used to preheat the newly supplied gas.

[0004] Solid balls made of alumina or the like have traditionally been widely used as heat storage bodies for radiant tube burners. Meanwhile, the use of honeycomb structures made of ceramics such as alumina as heat storage bodies has also been proposed (see, for example, Patent Document 1). Honeycomb structures have a large number of cells separated by partition walls, and the cells extend in a single direction, which offers the advantage of low pressure loss associated with gas flow. Furthermore, honeycomb structures have a significantly larger surface area than solid balls, which offers the advantage of a larger area contributing to heat exchange.

[0005] Heat storage bodies with this honeycomb structure are arranged in the straight tube section (the section where the tube is straight) of the radiant tube. Conventionally, honeycomb structures that are long in the axial direction of the cells have been used as heat storage bodies with honeycomb structure arranged inside the radiant tube. Since being long in the axial direction of the cells means being long in the axial direction of the radiant tube, fewer honeycomb structures need to be installed inside the radiant tube, making installation easier.

[0006] However, the fact that the honeycomb structure is long in the axial direction of the cells also means that it is long in the direction of gas flow. Therefore, when storing heat from high-temperature gas and releasing it to low-temperature gas, a temperature difference (temperature distribution) is likely to occur between one side and the other side in the gas flow direction in the heat storage body having the honeycomb structure. As a result, damage such as cracks and fractures may occur in the heat storage body having the honeycomb structure due to thermal stress.

[0007] In addition, the heat generated by the burner can cause the straight tube sections of the radiant tube to bend. In this case, if the honeycomb structured heat storage body is long in the axial direction of the cells, the curved section of the deformed tube can interfere with the heat storage body when trying to remove it from the radiant tube for replacement, making it impossible to remove.

[0008] Therefore, it has been proposed to use multiple honeycomb structures, each short in the axial direction of the cells, as a heat storage medium in the straight tube section of a radiant tube, so that they are connected in the axial direction of the cells (see, for example, Patent Document 2). In this case, the honeycomb structures that are short in the axial direction of the cells correspond to multiple honeycomb structures that are long in the axial direction of the cells, divided into multiple pieces. Because the individual honeycomb structures are short in the gas flow direction, temperature differences are less likely to occur, and damage due to thermal stress is suppressed. Furthermore, even if the straight tube section of the radiant tube is deformed and curved due to heating by the burner, honeycomb structures that are short in the axial direction of the cells have the advantage of being easier to remove from the radiant tube than honeycomb structures that are long in the axial direction of the cells.

[0009] However, when a honeycomb structure is used as a heat storage body, the gas exchanging heat with the heat storage body flows inside the cells. Therefore, when multiple honeycomb structures are connected in the axial direction of the cells, if the cells are misaligned between adjacent honeycomb structures, pressure loss in the gas flow increases. If the pressure loss of the gas flowing through the cells increases, heat exchange is not performed efficiently. In addition, gas tends to stagnate near the boundaries of adjacent honeycomb structures, which causes a local increase in the temperature of the honeycomb structure and may cause damage due to thermal stress.

[0010] Furthermore, if gas tends to stagnate due to pressure loss, impurities contained in the exhaust gas tend to adhere to the inside of the cells, making the cells more susceptible to clogging. When cells become clogged, not only does the gas not flow properly and heat exchange cannot be performed, but the gas blocked in that area can locally increase the temperature of the honeycomb structure, which may cause damage due to thermal stress. Such problems become more severe as the number of honeycomb structures connected in the axial direction of the cells increases.

[0011] It would be sufficient if the cell positions of multiple honeycomb structures connected in the axial direction of the cells could be aligned, but radiant tubes are typically cylindrical, and the shape of honeycomb structures is often cylindrical to match the shape of the tube. Therefore, when inserting a honeycomb structure into a radiant tube, the honeycomb structure easily rotates inside the tube. Therefore, when inserting multiple honeycomb structures connected in the axial direction of the cells into a radiant tube one by one, it is very difficult to align the cell positions. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Publication number 2-23950 [Patent Document 2] Patent No. 3754507 Summary of the Invention [Problem to be solved by the invention]

[0013] In view of the above-mentioned circumstances, the present invention aims to provide a heat storage body in which a plurality of honeycomb structures are arranged in the axial direction of the extension of the cells, and in which the positions of the cells in each honeycomb structure are misaligned with those of adjacent honeycomb structures, thereby preventing an increase in pressure loss during gas flow, and a method for manufacturing such a heat storage body. [Means for solving the problem]

[0014] In order to solve the above problems, the heat storage body for a radiant tube burner according to the present invention (hereinafter sometimes simply referred to as "heat storage body") has the following features: "A heat storage body in which a plurality of ceramic honeycomb structures each having a plurality of cells separated by partition walls arranged in a row extending in a single direction are connected in an axial direction of the cells with the open end faces of the cells facing each other, the plurality of honeycomb structures are integrated by adhesive tapes attached to side peripheral surfaces of the adjacent honeycomb structures so as to straddle the boundaries between the honeycomb structures adjacent in the axial direction in which the cells extend, The adhesive tape is made of an organic material that loses its tape shape when heated.

[0015] The heat storage body of this configuration can be manufactured by the following heat storage body manufacturing method. "A method for manufacturing a heat storage body in which a plurality of ceramic honeycomb structures each having a plurality of cells partitioned by partition walls arranged in a row extending in a single direction are connected in an axial direction of the cells with the open end faces of the cells facing each other, a plurality of honeycomb structures are integrated by adhering adhesive tape to a side peripheral surface of each of the adjacent honeycomb structures so as to straddle a boundary between the honeycomb structures adjacent in the axial direction in which the cells extend, The adhesive tape is made of an organic material that loses its tape shape when heated.

[0016] Hereinafter, the "axial direction in which the cells extend" will be referred to as the "axial direction of the cells." Conventionally, multiple honeycomb structures have been joined together to increase the cross-sectional area perpendicular to the axial direction of the cells. This is because, although honeycomb structures are generally formed by extrusion molding, it is difficult to form large molded bodies using extrusion molding. Therefore, in order to increase the amount of gas flowing through the honeycomb structure, multiple honeycomb structure segments are joined together so that the axial directions of the cells are parallel and the open end faces of the cells are flush with each other, thereby increasing the cross-sectional area perpendicular to the axial direction of the cells. In contrast, in the present invention, multiple honeycomb structures are joined together in the axial direction of the cells with the open end faces facing each other. Joining multiple honeycomb structures in this direction was not possible in the prior art.

[0017] In addition, it has been conventionally believed that a bonding agent (bonding material) with a composition similar to that of the ceramic material constituting the honeycomb structures is desirable when bonding multiple honeycomb structures. This approach is believed to result in similar thermal expansion coefficients between the honeycomb structures and the bonding layer, making it less likely that thermal stress will occur and damage resulting from it will occur. Conventional bonding layers primarily composed of ceramic materials have high mechanical strength, making it easier to maintain the bonded, integrated state of multiple honeycomb structures for a long period of time. In contrast, the present invention uses adhesive tape to bond multiple honeycomb structures together. When heavy objects such as honeycomb structures are bonded with adhesive tape, the multiple honeycomb structures are not firmly integrated.

[0018] The inventors wanted to maintain a state in which multiple honeycomb structures are integrated during the installation of the heat storage body inside the radiant tube, but to weaken the bonds between the honeycomb structures and ultimately separate the honeycomb structures when the heat storage body is installed inside the radiant tube burner and is actually used. If multiple honeycomb structures were firmly joined in the axial direction of the cells, the multiple honeycomb structures would act like a single rigid body. This would result in the same problems as in the conventional case in which a honeycomb structure long in the axial direction of the cells was used as a heat storage body for a radiant tube burner, namely, a temperature difference easily occurs between one side and the other in the gas flow direction, causing damage to the heat storage body due to thermal stress, and a problem in which the heat storage body cannot be removed from the tube if the straight tube section of the radiant tube is deformed and curved by heating by the burner.

[0019] In contrast, in the present invention, the adhesive tape used to bond the honeycomb structures in the axial direction of the cells is made of an organic material that loses its tape shape when heated. Therefore, when the regenerator body becomes hot during actual use of a radiant tube burner, the adhesive tape loses its tape shape and the regenerator body separates into multiple honeycomb structures. This achieves the effects of dividing the honeycomb structure constituting the regenerator body into multiple pieces, namely, reducing the temperature difference in the gas flow direction between the separated honeycomb structures and suppressing damage caused by thermal stress. Furthermore, even if the straight tube portion of the radiant tube is deformed by heating with the burner, the separated honeycomb structures can be easily removed from the tube.

[0020] In the present invention, prior to the installation of the heat storage body inside the radiant tube, the plurality of honeycomb structures are joined in the axial direction of the cells. In other words, the work of joining the plurality of honeycomb structures in the axial direction of the cells while aligning the cell positions of adjacent honeycomb structures in each of the plurality of honeycomb structures can be performed at a factory where the heat storage body is manufactured, rather than at the site where the radiant tube burner is used. Therefore, the work of aligning the cell positions is much easier than when aligning the cell positions while inserting the plurality of honeycomb structures one by one into the radiant tube at the site where the radiant tube burner is used.

[0021] Furthermore, since the heat storage body of the present invention is made up of multiple honeycomb structures integrated together, even if they are not firmly joined, at the site where the radiant tube burner is used, it is sufficient to simply insert the integrated heat storage body into the radiant tube, which makes the work of installing the heat storage body inside the radiant tube extremely easy.

[0022] The heat storage body for a radiant tube burner according to the present invention has the following features in addition to the above configuration: "The adhesive tape has adhesive surfaces on both sides, The adhesive surface that is not attached to the side peripheral surface has an inorganic fiber sheet wound around the side peripheral surface of the heat storage body attached to it.

[0023] When a heat storage body is inserted into a radiant tube, if there is a large gap between the inner surface of the tube and the heat storage body, rattles. If the rattle is too great, the heat storage body may be damaged, such as chipped. In this configuration, an inorganic fiber sheet is wrapped around the side surface of the heat storage body. Because the inorganic fiber sheet is elastic, it fills the gap between the inner surface of the radiant tube and the heat storage body, suppressing rattles. Furthermore, because the inorganic fiber sheet is heat-resistant, it does not lose its function as a cushioning material even when the heat storage body becomes hot during operation of the radiant tube burner.

[0024] In this configuration, one side of the adhesive tape is attached to the peripheral side surface of the honeycomb structure, and the other side has an inorganic fiber sheet attached to it. As a result, the inorganic fiber sheet is also integrated with the heat storage body via the adhesive tape, so that when the heat storage body is inserted into the radiant tube, the inorganic fiber sheet does not shift, and the heat storage body and inorganic fiber sheet can be installed inside the radiant tube with good workability.

[0025] In addition, in this configuration, the adhesive tape has the function of both joining multiple honeycomb structures in the axial direction of the cells and holding an inorganic fiber sheet in a heat storage body made up of multiple honeycomb structures, making the configuration simple.

[0026] The heat storage body for a radiant tube burner according to the present invention has the following features in addition to the above configuration: "The plurality of honeycomb structures have the same cell shape, the same cell density, and the same partition wall thickness, When the state in which the positions of the cells of adjacent honeycomb structures in the axial direction of the cells are aligned is defined as a cell misalignment angle of zero degrees, and when the angle obtained by rotating one honeycomb structure relative to the other honeycomb structure around an axis that is parallel to the axial direction of the cells and passes through the center of the honeycomb structure as the rotation center axis is referred to as the cell misalignment angle, the cell misalignment angle can be defined as being equal to or greater than zero degrees and equal to or less than 11 degrees.

[0027] As will be described in detail later, as a result of investigation, it was found that when the cell misalignment angle between honeycomb structures adjacent in the cell axial direction is 11 degrees or less, the pressure loss in gas flow does not increase significantly compared to when the cell misalignment angle is zero degrees. Therefore, by adopting this configuration, it is possible to provide a heat storage body in which a plurality of honeycomb structures are joined in the cell axial direction while suppressing an increase in pressure loss in gas flow. [Effects of the Invention]

[0028] As described above, according to the present invention, it is possible to provide a heat storage body in which a plurality of honeycomb structures are arranged in the axial direction of the extension of the cells, and in which the positions of the cells in each honeycomb structure are shifted between adjacent honeycomb structures, thereby suppressing an increase in pressure loss during gas flow, and a method for manufacturing the heat storage body. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1(a) is an exploded perspective view showing the components of a heat storage body according to one embodiment of the present invention, and FIG. 1(b) is a plan view of a honeycomb structure which is a component of the heat storage body. [Figure 2] FIG. 1(a) is a perspective view of a heat storage body according to one embodiment of the present invention, and FIG. 1(b) is a perspective view of a heat storage body according to a modified example. [Figure 3] FIG. 10 is a perspective view of a heat storage body according to another embodiment. [Figure 4] 10 is a graph showing the relationship between the cell misalignment angle and the pressure loss change ratio. DETAILED DESCRIPTION OF THE INVENTION

[0030] A specific embodiment of the present invention, a heat storage body 1 for a regenerative radiant tube burner (simply referred to as "heat storage body 1"), and its manufacturing method will be described below with reference to Figures 1 and 2. The heat storage body 1 is composed of a plurality of honeycomb structures 10 of the same configuration. The honeycomb structure is a structure comprising a large number of cells 15 separated by partition walls 13 arranged in a row extending in a single direction.

[0031] The multiple honeycomb structures 10 have the same shape in cross section (hereinafter referred to as "cross section") in a direction perpendicular to the axial direction of the cells 15 (direction P in FIG. 1(a) and a direction parallel thereto). Each of the multiple honeycomb structures 10 has a circular outer shape in cross section, and a circular hole 10h concentric with the outer circle is formed through the center.

[0032] The honeycomb structures 10 are made of the same ceramic material, such as alumina, zirconia, mullite, cordierite, and silicon carbide.

[0033] The shape of the cells 15, the density of the cells 15, and the thickness of the partition walls 13 separating the cells 15 are the same for each of the multiple honeycomb structures 10. Such a honeycomb structure 10 can be manufactured by extruding a cylindrical honeycomb structure, firing the formed body, and then drilling circular holes 10h. The cells 15 are open on the inner circumferential surfaces of the circular holes 10h, but the open portions of the cells 15 may be closed by applying a coating material having a composition similar to that of the ceramics constituting the honeycomb structure 10 to the inner circumferential surfaces of the circular holes 10h.

[0034] The heat storage body 1 of this embodiment is formed by bonding a plurality of honeycomb structures 10 having the above-described configuration in the axial direction of the cells 15 with adhesive tape 21. The adhesive tape 21 is made of an organic material that loses its tape shape when heated. The temperature at which the adhesive tape 21 loses its tape shape may be lower than the temperature reached in the space in which the heat storage body 1 is disposed during operation of the radiant tube burner. During operation of the radiant tube burner, the temperature in the space in which the heat storage body 1 is disposed reaches a high temperature of 800°C to 1000°C. Therefore, typical organic materials used in adhesive tapes burn or decompose at this temperature, causing the adhesive tape to lose its tape shape. Note that "losing its tape shape" does not only mean that the adhesive tape is completely lost due to combustion or decomposition, but also means that even if residue remains after combustion or decomposition, the tape shape is not maintained.

[0035] Either a tape having adhesive properties on only one side or a tape having adhesive properties on both sides can be used as the adhesive tape 21. Here, a case where the adhesive tape 21 is a tape having adhesive properties on both sides (hereinafter referred to as "double-sided tape") will be exemplified.

[0036] As shown in FIG. 2(a), the adhesive tape 21 is attached to the side peripheral surface S2 of each of the adjacent honeycomb structures 10 so as to straddle the boundary between the adjacent honeycomb structures 10 in the axial direction of the cells 15. Here, an example is shown in which the longitudinal direction of the adhesive tape 21 is parallel to the axial direction of the cells 15, and the length of one adhesive tape 21 is the length that covers the entirety of the multiple honeycomb structures 10 joined in the axial direction of the cells 15. Such adhesive tape 21 is attached to the honeycomb structure 10 at multiple locations. For example, multiple adhesive tapes 21 can be attached at equal angular intervals with respect to the central axis of the honeycomb structure (corresponding to the line P in FIG. 1(a)).

[0037] However, if the adhesive tape 21 is attached to the side peripheral surface S2 of both honeycomb structures 10 so as to straddle the boundary between at least two adjacent honeycomb structures 10 in the axial direction of the cells 15, and if the adhesive tape 21 is attached to all honeycomb structures 10 so as to straddle the boundary between adjacent honeycomb structures 10, it is also possible to use an adhesive tape 21 that is shorter than the adhesive tape 21 shown in Figure 2(a).

[0038] 2(b), in addition to the adhesive tape 21 attached so as to straddle the boundary between adjacent honeycomb structures 10 in the axial direction of the cells 15, an adhesive tape 22 may be attached to the side peripheral surface S2 of each honeycomb structure 10 so as to be wrapped around in the circumferential direction. The adhesive tape 22 is attached to the honeycomb structure 10 so as to press the adhesive tape 21 from the outside. The adhesive tape 22 may be a double-sided tape like the adhesive tape 21. The adhesive tape 22 does not have the function of joining adjacent honeycomb structures 10 in the axial direction of the cells 15. However, the surface area of ​​the honeycomb structures 10 on which the adhesive tape 21 acts to hold the honeycomb structures 10 is increased by the adhesive tape 22, thereby making it possible to more stably join multiple honeycomb structures 10 together. Of the adhesive tapes 21 and 22, the adhesive tape 21 corresponds to the "adhesive tape" in the present invention.

[0039] The bonding with the adhesive tape 21 is easier to perform if the multiple honeycomb structures 10 to be bonded are stacked one on top of the other. By aligning the positions of the cells 15 in each honeycomb structure 10 during this stacking, it is possible to obtain a heat storage body 1 in which multiple honeycomb structures 10 are integrated, with each of the multiple cells 15 belonging to each honeycomb structure 10 communicating so as to be positioned on the same line with the cells 15 belonging to the other honeycomb structures 10. For example, by passing a long, linear member such as a wire through the cells 15 belonging to each of the multiple honeycomb structures 10 at the same position, the multiple honeycomb structures 10 can be stacked in a state in which the cells 15 are positioned, thereby aligning the positions of the cells.

[0040] The manufacturing method described above produces a heat storage body 1 in which a plurality of honeycomb structures 10 are integrated with adhesive tape 21 without misalignment of the cells 15. The heat storage body 1 has a circular cross-sectional outer shape and has a circular hole 10h at the center of the cross-section that is concentric with the outer circle. Such a heat storage body 1 is arranged in the straight pipe section of a radiant tube. The straight pipe section of the radiant tube has a double structure consisting of a cylindrical outer tube and a cylindrical inner tube that is concentric with the outer tube, and the heat storage body 1 is inserted into the space between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube. The internal space of the inner tube is the space into which a burner is inserted.

[0041] In this embodiment, when inserting the heat storage body 1 into the radiant tube, an inorganic fiber sheet (not shown) is wrapped around the side periphery of the heat storage body 1. Because the adhesive tapes 21 and 22 are double-sided tapes, the inorganic fiber sheet can be attached to the side opposite to the side attached to the side periphery S2 of the honeycomb structure 10. This maintains the state in which the inorganic fiber sheet is wrapped around the side periphery of the heat storage body 1, and the heat storage body 1 is inserted into the radiant tube in this state. Therefore, the inorganic fiber sheet does not shift relative to the heat storage body 1, and both the heat storage body 1 and the inorganic fiber sheet can be inserted into the radiant tube in a single operation.

[0042] If multiple honeycomb structures are not integrated, it would take time and effort to insert each honeycomb structure into the radiant tube one by one. Furthermore, when inserting multiple honeycomb structures into the radiant tube, it is necessary to align the cells so that each of the many cells belonging to each honeycomb structure is aligned on the same line as the cells belonging to other honeycomb structures. It is extremely difficult to align the cells while inserting the honeycomb structures into the radiant tube.

[0043] In contrast, the heat storage body 1 of this embodiment is made up of a plurality of honeycomb structures 10 integrated together with the cells 15 aligned, so it is sufficient to simply insert the integrated heat storage body 1 into the internal space of the radiant tube. This makes it extremely easy to install the heat storage body 1 inside the radiant tube.

[0044] Here, if multiple honeycomb structures are firmly fixed together by adhesive bonding or the like, the integrated state is stable, but there is no point in constructing a heat storage body from multiple honeycomb structures. In other words, if multiple honeycomb structures are firmly integrated with a highly adhesive adhesive to form a heat storage body, the entire heat storage body becomes like a single rigid body long in the axial direction of the cells. As a result, temperature differences in the heat storage body are likely to occur in the gas flow direction, and there is a risk of damage due to thermal stress. Furthermore, if the straight tube portion of the radiant tube is deformed and curved by heating from the burner, the heat storage body, which is joined together like a single rigid body long in the axial direction of the cells, cannot be removed from the radiant tube, making it impossible to replace the heat storage body.

[0045] In contrast, the heat storage body 1 of this embodiment is formed by joining multiple honeycomb structures 10 in the axial direction of the cells 15 with adhesive tape 21. The adhesive tape 21 is made of an organic material that loses its tape shape when heated. Therefore, when the heat storage body 1 becomes hot during operation of the radiant tube burner, the adhesive tape 21 loses its tape shape and can no longer connect the multiple honeycomb structures 10, so the honeycomb structures 10 separate into individual honeycomb structures 10. Temperature differences are less likely to occur in the gas flow direction in the individual honeycomb structures 10, and damage caused by thermal stress is suppressed.

[0046] Here, even if the heat storage body 1 separates into a plurality of honeycomb structures 10 as the adhesive tape 21 loses its tape shape, the honeycomb structures 10 already inserted inside the radiant tube will not move naturally, such as by rotating. Therefore, even if the heat storage body 1 separates into a plurality of honeycomb structures 10 after being inserted into the radiant tube, the positions of the cells 15 in the plurality of honeycomb structures 10 will remain aligned.

[0047] After the heat storage body 1 is installed inside the radiant tube and the radiant tube burner has been in actual use for a certain period of time, the multiple honeycomb structures 10 that made up the heat storage body 1 are separated. Therefore, even if the straight tube portion of the radiant tube is deformed and curved due to heating by the burner, the separated honeycomb structures 10 can be individually removed from the radiant tube, making it easy to replace the heat storage body 1.

[0048] Next, we investigated the relationship between the degree of cell misalignment and the pressure loss of the gas flowing through the honeycomb structures when multiple honeycomb structures were connected in the axial direction of the cells. For multiple heat storage units, two honeycomb structures of the same configuration were joined together with different degrees of cell misalignment. The pressure of the gas flowing into the heat storage unit and the pressure of the gas exhausting from the heat storage unit were measured. The honeycomb structures had a circular cross-sectional shape and were perforated with a circular hole concentric with the outer circle. The rotation axis (corresponding to line P in Figure 1) was a line passing through the center of the circular hole and parallel to the axial direction of the cells. When two honeycomb structures were stacked so that the cell positions were perfectly aligned, this was defined as a "zero degree misalignment angle." The "misalignment angle" was the angle by which one honeycomb structure was rotated relative to the other honeycomb structure around the rotation axis. The misalignment angle was varied to 5, 8, 11, 22.5, and 45 degrees. The flow rate of the gas flowing into the heat storage body is 4.0 Nm 3 / min, 6.0Nm 3 / min, 9.0Nm 3 / min.

[0049] The pressure difference (pressure loss) between the gas flowing into the heat storage body and the gas being discharged from the heat storage body under each condition was calculated, and the results are shown in Table 1. Figure 4 also shows the pressure loss change ratio, assuming that the pressure loss when the cell misalignment angle is zero degrees is "1."

[0050] [Table 1]

[0051] As can be seen from Figure 4, regardless of the gas flow rate, when the cell misalignment angle is in the range of 0 to 11 degrees, the pressure loss change ratio remains below approximately 1.1, meaning that the pressure loss is not large. On the other hand, when the cell misalignment angle is 22.5 degrees or more, the pressure loss change ratio increases significantly to 1.3 or more. From this, it was considered desirable that when multiple honeycomb structures are joined in the axial direction of the cells to form a heat storage body, the cell misalignment angle between adjacent honeycomb structures should be in the range of 0 to 11 degrees.

[0052] The present invention has been described above by citing preferred embodiments, but the present invention is not limited to the above embodiments, and various improvements and design changes are possible as described below, without departing from the spirit of the present invention.

[0053] For example, in the above description, FIGS. 1 and 2 illustrate a case where the honeycomb structure 10 serving as a unit for connecting the cells 15 in the axial direction is an integrated honeycomb structure 10 obtained by firing an extrusion-molded molded body. However, this is not limiting. As shown in FIG. 3, a honeycomb structure 10C formed by joining multiple honeycomb structured segments 10s together so that the axial directions of the cells 15 are parallel and the end faces S1 of the segments are flush with each other can also be used as a unit for connecting the cells 15 in the axial direction. Here, the honeycomb structure 10C is illustrated as an example, in which the segments 10s are formed by firing molded bodies extruded into a cubic or rectangular parallelepiped shape, and the side peripheral surfaces of the segments 10s are bonded together with an adhesive to form a single unit. The honeycomb structure 10C is then processed to have a circular cross-sectional shape and circular holes 10h that are concentric with the outer circle and penetrate the honeycomb structure 10C in the axial direction. The adhesive is a mixture of ceramic powder, organic binder, and inorganic binder, and the adhesive layer 30 firmly bonds the segments 10s together. Therefore, when a heat storage body 1B in which multiple honeycomb structures 10C are joined in the axial direction of the cells 15 with adhesive tape 21 is installed inside a radiant tube burner and actually used, and the heat storage body 1B becomes hot, even if the adhesive tape 21 loses its tape shape and the heat storage body 1B separates into multiple honeycomb structures 10C, the bonding by the adhesive layer 30 will be weakened and the honeycomb structure 10C will not separate into multiple segments 10s. [Explanation of symbols]

[0054] 1 Heat storage body 13 Bulkhead 15 cells 21 Adhesive tape S1 end face S2 side surface

Claims

1. A heat storage body, comprising a plurality of ceramic honeycomb structures each having a plurality of cells partitioned by partition walls arranged in a row extending in a single direction, the plurality of honeycomb structures being arranged in an axial direction in which the cells extend, with open end faces of the cells facing each other, the plurality of honeycomb structures are integrated by adhesive tapes attached to side peripheral surfaces of the adjacent honeycomb structures so as to straddle the boundaries between the honeycomb structures adjacent in the axial direction in which the cells extend, The adhesive tape is made of an organic material that loses its tape shape when heated. A heat storage body for a radiant tube burner characterized by:

2. The adhesive tape has adhesive surfaces on both sides, An inorganic fiber sheet is attached to the adhesive surface that is not attached to the side peripheral surface and is wound around the side peripheral surface of the heat storage body.

2. A heat storage body for a radiant tube burner according to claim 1.

3. The plurality of honeycomb structures have the same cell shape, the same cell density, and the same partition wall thickness, When the position of the cells of the adjacent honeycomb structures in the axial direction of the cells coincides, the cell misalignment angle is defined as zero degrees. When the cell misalignment angle is defined as the angle at which one honeycomb structure is rotated relative to the other honeycomb structure around an axis that is parallel to the axial direction of the cells and passes through the center of the honeycomb structure as the rotation center axis, the cell misalignment angle is equal to or greater than zero degrees and equal to or less than 11 degrees.

2. A heat storage body for a radiant tube burner according to claim 1.

4. A method for manufacturing a heat storage body, comprising: a plurality of ceramic honeycomb structures each having a plurality of cells partitioned by partition walls arranged in a row extending in a single direction; the plurality of ceramic honeycomb structures are arranged in a row in an axial direction of the cells, with open end faces of the cells facing each other; a plurality of honeycomb structures are integrated by adhering adhesive tape to a side peripheral surface of each of the adjacent honeycomb structures so as to straddle a boundary between the honeycomb structures adjacent in the axial direction in which the cells extend, The adhesive tape is made of an organic material that loses its tape shape when heated. A method for manufacturing a heat storage body for a radiant tube burner, characterized by the above-mentioned.

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