JP2017032237A - Heat reservoir - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat reservoir high in strength, thermal shock resistance and efficiency of heat exchange, excellent in assemblability, and used in a heat storage burner.SOLUTION: A heat reservoir 1 is used in a heat storage burner 4 that alternately circulates exhaust gas heated by combustion of the burner and gas supplied for combustion of the burner to thereby perform heat exchange. The heat reservoir comprises a cylindrical ceramics having a ratio (L/d) of an axial length L to an outer diameter dof more than 0.8 and less than 1.2.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a heat storage body used for a heat storage burner.

  In a forging furnace, a heat treatment furnace, a melting furnace, a firing furnace, and the like, a regenerative burner (regenerative burner) may be used to increase the temperature in the space by burning the burner. In the regenerative burner, the gas flow direction is switched at intervals of several tens of seconds so that the exhaust gas that has become hot due to the burner combustion and the gas that is supplied for the burner combustion flow alternately to the heat storage body. It is a burner. By switching the flow direction, the heat of the exhaust gas is recovered by the heat storage body, and the recovered heat is used to preheat the gas newly supplied for the burner combustion.

Therefore, the regenerative burner has high combustion efficiency and can save fuel, thereby contributing to energy saving and reducing carbon dioxide emitted. Such a heat storage burner includes a type using a pair of burners each combined with a heat storage body (twin regenerative burner) and a type switching a gas flow direction with one burner (self regenerative burner).
Ceramic balls (Patent Document 1), honeycomb structures (Patent Document 2), and ceramic cylinders (Patent Document 3) are used as the heat storage body for the heat storage burner.
Patent Document 1 describes that the packing density of the heat storage body is increased by using ceramic balls having different sizes.

  Patent Document 2 describes a technique of using a ceramic honeycomb structure such as alumina, cordierite, and mullite as a heat storage for a heat storage burner. The honeycomb structure has an advantage that the surface area is very large as compared with the ball. Further, the honeycomb structure has an advantage that the pressure loss accompanying the gas flow is small.

  Patent Document 3 describes a technique using a ceramic cylinder. Patent Document 3 describes that ceramic cylinders are aligned and arranged at least on the rear stage side. Ceramic cylinders have the advantage of low pressure loss and large surface area.

JP 2003-343829 A JP 2003-287379 A JP 2005-249239 A

  However, the technique described in Patent Document 1 has a problem in that the pressure loss is large because the gas flows through the gaps between the balls filled in the casing. Further, since the surface area of the ball is small, there is also a problem that heat exchange becomes insufficient because the ball cannot be used up to the center.

  Furthermore, when the diameter of ceramic balls is increased to increase the heat capacity, the temperature difference (partial temperature difference) between the surface and the interior (center) increases, and cracks are caused by volume changes (thermal expansion / contraction). There is a problem that it is easy to occur.

In the honeycomb structure or the ceramic cylinder described in Patent Documents 2 to 3, the partition walls are very thin in order to obtain a large surface area. Therefore, the heat storage body having a honeycomb structure (ceramics cylinder) has a problem of low strength. In addition, the thin partition wall indicates that the partial heat capacity of the partition wall is reduced, and as a result, not only the amount of heat exchangeable (decrease in heat exchange property) is caused, but also the heat resistance of the partition wall itself is decreased. Invite.
In addition, there is a problem that cracks and cracks are likely to occur due to a rapid temperature change that accompanies repeated heat storage and heat dissipation, that is, thermal shock resistance is low.

In the case of a honeycomb structure, in order to improve thermal shock resistance, it has been studied to use a honeycomb structure having a reduced shape. However, the small honeycomb structures need to be regularly arranged, and as a result, there is a problem that the assembling cost becomes enormous.
Furthermore, the ceramic cylinder of Patent Document 3 has a problem that the axial length is long and the assembling cost becomes enormous.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a heat storage body used for a heat storage burner having high strength, thermal shock resistance, and high heat exchange efficiency and excellent assembly properties. To do.

  In order to solve the above problems, as a result of repeated studies on the heat storage body used in the heat storage type burner, the present invention has been made.

The heat storage body of the present invention is a heat storage body used in a heat storage burner that performs heat exchange by alternately circulating exhaust gas heated by combustion of the burner and gas supplied for combustion of the burner, and is axially The ratio (L / d 2 _{O 3} ) of the length (L) to the outer diameter (d 2 _{O 3} ) is greater than 0.8 and less than 1.2, and is characterized by being made of cylindrical ceramics.

  The heat storage body of this invention consists of cylindrical ceramics. By making the heat storage body cylindrical, it can be heated from the inside (inner peripheral surface) and outside (outer peripheral surface) in the radial direction, and partial temperature unevenness in the radial direction (thickness direction of the heat storage body) does not occur. It will have high thermal shock resistance. The cylindrical shape of the heat storage body indicates a shape having a hollow portion in the axial center and extending along the axial direction. Further, the cylindrical shape is a shape in which openings are formed on both end surfaces in the axial direction.

Then, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) that is less than greater than 0.8 1.2, size of the regenerator is close to a cubic shape It becomes. According to this shape, the heat storage body can be poured into the housing space of the heat storage burner and assembled, and the assembled heat storage bodies are randomly arranged. When the heat accumulators are randomly arranged, uniform heat exchange is possible in the accommodation space.
As described above, the heat storage body of the present invention is a heat storage body that has high strength, thermal shock resistance, and high efficiency of heat exchange and is excellent in assemblability.

It is a perspective view of the thermal storage body of Embodiment 1. FIG. It is sectional drawing of the thermal storage body of Embodiment 1. FIG. It is the block diagram which showed the assembly | attachment of the thermal storage body of Embodiment 1. FIG. It is a perspective view of the thermal storage body of Embodiment 2. FIG. It is sectional drawing of the thermal storage body of Embodiment 2. FIG. It is a perspective view of the thermal storage body of Embodiment 3. FIG. It is sectional drawing of the thermal storage body of Embodiment 3. FIG. It is sectional drawing of the thermal storage body of Embodiment 4. It is sectional drawing of the thermal storage body of Embodiment 5. FIG. It is radial direction sectional drawing of the thermal storage body of Embodiment 6. FIG. It is radial direction sectional drawing of the thermal storage body of Embodiment 7. FIG. It is a figure which shows the structure of the thermal storage type burner with which the thermal storage body of an Example is assembled | attached.

Hereinafter, the heat storage body of the present invention will be specifically described using embodiments.
[Embodiment 1]
(Heat storage)
The heat storage body 1 of this embodiment is a heat storage body used for a heat storage burner that performs heat exchange by alternately circulating exhaust gas heated by combustion of a burner and gas supplied for combustion of the burner.

  The heat storage body 1 of this form consists of cylindrical porous ceramics, as shown in FIGS. FIG. 1 is a perspective view of the heat storage body 1. 2 is a cross-sectional view taken along line II-II in FIG.

The heat storage body 1 of this form consists of cylindrical porous ceramics. Here, the cylindrical shape indicates a shape in which a cross-sectional shape perpendicular to the axial direction forms an annular shape. Since the heat storage body 1 has a cylindrical shape, the thickness of the ceramic in the radial direction becomes uniform. And when the thermal storage body 1 is exposed to each gas, a cylindrical axial center part (inner surface) and the exterior (outer surface) will contact each gas. And since the temperature change arises from the cylindrical both surfaces, the heat storage body 1 of this form does not produce the partial temperature nonuniformity in the thickness direction. That is, the heat storage body 1 has high thermal shock resistance.
Moreover, the thermal storage body 1 of this form will have a large surface area by becoming a cylindrical shape. The area in contact with each gas increases, and the performance of heat exchange is improved.

Furthermore, by forming a cylindrical shape, it is possible to reduce the mass of the columnar solid body (a shape without a hollow shaft, a dense body). If the heat storage body 1 is reduced in weight, not only can the heat storage body 1 be handled easily, but a large mass will not be applied to the burner when it is assembled to the heat storage burner apparatus, and damage to the apparatus can be suppressed.
As shown in FIGS. 1 and 2, the heat storage body 1 of this embodiment is formed such that both end faces in the axial direction spread perpendicularly to the axial direction.

In the heat storage body 1 of this embodiment, the ratio (L / d _O ) between the axial length (L) and the outer diameter (d _O ) is greater than 0.8 and less than 1.2. In the heat storage body 1 of the present embodiment, 0.8 <(L / d 2 _{O 3} ) <1.2 is satisfied, so that the assemblability of the heat storage body 1 is improved. In addition, the length (L) in the axial direction in this embodiment corresponds to the distance between both end surfaces of the heat storage body 1 in the axial direction. Further, in the cylindrical heat storage element 1 of this embodiment, the outer diameter (d 2 _{O 3} ) corresponds to the diameter of the cylinder.

  Specifically, when the outer shape of the heat storage body 1 is included in this range, the shape of the heat storage body 1 approximates that of a conventional ceramic ball. If it does so, the handling similar to the conventional ceramic ball | bowl will be attained, and the assembly | attachment of the thermal storage body 1 can be poured and assembled (filling the accommodation space). That is, the heat storage body 1 can be easily handled.

  Moreover, when the external shape of the heat storage body 1 is included in this range, the heat storage body 1 is randomly arranged when the assembly of the heat storage bodies 1 is poured and assembled. When arranged randomly, the amount of contact with each gas increases as compared with the arrangement. That is, the area in contact with each gas increases, and the heat exchange performance is improved.

When the ratio (L / d _O ) between the axial length (L) and the outer diameter (d _O ) is less than 0.8, the axial length with respect to the outer diameter becomes shorter (as a whole, the shorter axis It becomes a shape), and it becomes easy to arrange the heat storage bodies 1 when assembled. Moreover, even if the ratio (L / d 2 _{O 3} ) exceeds 1.2, the heat storage elements 1 are easily arranged in the same manner.

  The size of the heat storage element 1 represented by the length (L) in the axial direction is not limited, but is preferably the same size (size) as the diameter of a conventional ceramic ball. That is, it is preferably 6 to 30 mm, and more preferably 8 to 20 mm.

Regenerator 1 of this embodiment, as shown in FIG. 2, the regenerator 1 tubular is, the ratio between the outer diameter _{(d O)} and an inner diameter _{(d I) (d O /} d I) 1.2 Greater than 4 In the cylindrical heat storage element 1, the inner diameter (d _I ) corresponds to the diameter of the hollow portion of the cylindrical shaft center. The ratio of the outer diameter and _{(d O)} and an inner diameter _{(d I) (d O /} d I) is related to the thickness in the radial direction of the cylindrical heat storage body 1. When the thickness of the heat accumulator 1 is in the range of 1.2 <(d _O / d _I ) <4, the above-described effects can be more exhibited.

If the ratio between the outer diameter _{(d O)} and an inner diameter _{(d I) (d O /} d I) is 1.2 or less, the thickness becomes thinner in the radial direction of the heat accumulation element 1. That is, the strength of the heat storage body 1 is reduced. Further, the amount of ceramics forming the heat storage body 1 is reduced, and the heat capacity related to the total amount of heat that can be transferred is also reduced.

The ratio of outer diameter _{(d O)} and an inner diameter _{(d I) (d O /} d I) is greater than 4, the thickness in the radial direction of the heat accumulation element 1 is excessively thick. That is, the thickness of the heat storage body 1 in the radial direction becomes too thick, and the distance between the shaft core portion (inner surface) and the outside (outer surface) becomes longer. In this case, temperature unevenness is likely to occur between the surface (inner surface and outer surface) and the central portion (the central portion in the thickness direction between the inner surface and outer surface) in the thickness direction, and the thermal shock resistance is reduced. It becomes easy to do.

  It is preferable that the heat storage body 1 of this form consists of porous ceramics. Porous ceramics have fine pores and form a large surface area. As a result, the contact area with each gas increases, and the heat exchange performance is improved. In addition, when the porous ceramic undergoes thermal expansion, the pore volume is reduced, thereby permitting thermal expansion, thereby improving the thermal shock resistance of the heat storage body. The pores of the porous ceramics may be independent pores (closed pores in the ceramic) or continuous pores (communication pores). Preferably, they are continuous pores (pores in which the pores exposed on the surface form irregularities on the surface).

  As long as the heat storage body 1 of this form is porous ceramics, the material will not be limited. That is, the material forming the heat storage body 1 may be a material (ceramics) forming the conventional heat storage body. Examples of this material include ceramics made of alumina, cordierite, mullite, silicon carbide and the like.

  Of these ceramics, silicon carbide ceramics mainly composed of silicon carbide having high thermal conductivity are most preferable. That is, by increasing the thermal conductivity, the heat of the exhaust gas from the burner can be recovered in a short time, and the recovered heat can be applied to the supply gas in a short time, so that the efficiency of heat exchange is increased. Specifically, as the thermal conductivity of each ceramic (dense body), silicon carbide (100 to 200 W / m · K), alumina (30 W / m · K), cordierite (4 W / m · K), It is known to be mullite (5 W / m · K).

In addition, the thermal expansion coefficient of silicon carbide is as small as about 4 × 10 ⁻⁶ / ° C. This is about 1/2 of the thermal expansion coefficient of alumina. That is, since silicon carbide has high thermal conductivity and low thermal expansion coefficient, it has excellent thermal shock resistance. Accordingly, silicon carbide is suitable as a heat storage body used in a heat storage burner that continues to undergo a rapid temperature change with repeated heat storage and heat dissipation.

  Furthermore, silicon carbide is lighter than other ceramics (particularly alumina). For this reason, if the thermal storage body 1 is formed with silicon carbide ceramics, a lightweight thermal storage body can be obtained compared with other ceramics. The lightweight heat storage body 1 can reduce the weight (mass, weight) applied to the heat storage burner when filled, and can achieve simplification (lower cost) of the device of the heat storage burner.

  When the heat storage body 1 consists of silicon carbide ceramics, it is preferable to contain an antioxidant. When the silicon carbide ceramic contains the antioxidant, the porous ceramic itself can be prevented from being oxidized and decomposed. In addition, the antioxidant exhibits the effect of increasing the strength of the porous ceramic itself.

  The antioxidant contained in the silicon carbide ceramic is not limited, but is preferably silicon oxide. Silicon oxide as an antioxidant can be generated by oxidizing silicon carbide ceramics (generated as glass by heat treatment in an oxidizing atmosphere).

  The porous ceramics of the heat storage body 1 of this embodiment is not limited in porosity, and is preferably made of porous ceramics of 50% or less. If the porosity exceeds 50%, the proportion of pores in the porous ceramics becomes excessive, and the strength of the heat storage body 1 is reduced.

  The lower limit of the porosity is not particularly limited. When the porosity is too small, the effect of having the porosity cannot be sufficiently exhibited. The porosity is preferably 5% or more.

  A preferable porosity varies depending on ceramics forming the heat storage body 1, and thus cannot be determined unconditionally. For example, when it consists of porous silicon carbide ceramics, it is 20 to 50%, and a more preferable porosity is 30 to 50%. When it consists of porous alumina ceramics, it is 5 to 40%, and a more preferable porosity is 5 to 20%.

(Regenerative burner)
The heat storage body 1 of this form is used for a heat storage burner. The regenerative burner performs heat exchange by alternately circulating the exhaust gas heated by the burner combustion and the gas supplied for the burner combustion. The heat storage body 1 of this form is utilized for this heat exchange. The heat storage burner is not particularly limited, and a heat storage burner having a conventionally known configuration can be used. In the heat storage type burner, the heat storage body 1 of this embodiment is stored (filled) in the storage space 2 (heat storage chamber) and used for heat exchange.
An example of the heat storage burner is the heat storage burner 4 having a configuration shown in FIG. In addition, as the heat storage type burner 4 having the configuration shown in FIG. 12, a heat storage type burner in which each gas flows along the vertical direction (vertical direction in the drawing) of the accommodation space 2 (heat storage chamber) is illustrated. The direction may be a substantially horizontal direction (lateral direction). Further, the direction of the burner is not particularly limited, and may be vertical or horizontal.

(Assembly of heat storage body)
The assembly of the heat storage body 1 will be specifically described using the column 3. As shown in FIG. 3, the column 3 extends in the vertical direction (vertical direction) through which each gas communicates, and defines the accommodation space 2 therein. The column 3 includes a cylindrical main body 30, a bottom plate 31, and an upper plate 32.
The cylindrical main body 30 is a cylindrical member whose axial direction extends in the vertical direction. The main body 30 is formed of a material whose inner peripheral surface has heat resistance.

  The main body portion 30 is provided with an input portion 33 for supplying the heat storage body 1 at the upper end portion in the vertical direction and a discharge portion 34 for discharging the heat storage body 1 at the lower end portion. The input unit 33 and the discharge unit 34 are provided to fill and discharge the heat storage body 1 into and from the housing space 2 and are closed when the heat storage body 1 does not pass through.

The bottom plate 31 is disposed at the lower end portion of the main body 30 and defines the lower end surface of the accommodation space 2. The bottom plate 31 supports passage of each gas and supports the filled heat storage body 1.
The upper plate 32 and the upper end of the main body 30 are disposed on the upper side, and the upper end surface of the accommodation space 2 is defined. The upper plate 32 allows passage of each gas.

  Since the bottom plate 31 and the upper plate 32 allow each gas to pass therethrough, the bottom plate 31 and the upper plate 32 have a mesh shape or a mesh shape in which a large number of vents are opened. The bottom plate 31 and the top plate 32 are also formed of a material having heat resistance.

The heat storage body 1 is input (supplied) into the accommodation space 2 from the input portion 33 of the main body 30 and is accommodated (filled). At this time, the discharge unit 34 is closed, and the input heat storage body 1 is accumulated in the accommodation space 2 and accommodated (filled). When the charging of the heat storage body 1 is completed, the charging unit 33 is closed. Thereby, the heat storage body 1 is filled in the accommodation space 2. At this time, the heat storage body 1 is randomly filled in the accommodation space 2 without being arranged.
When the heat storage body 1 is filled in the housing space 2, a heat storage burner can be used.

  The heat storage body 1 is discharged from the accommodation space 2 via the discharge portion 34 of the main body portion 30. The discharge part 34 is provided on the lower side in the axial direction, and the heat storage body 1 is discharged by opening the discharge part 34. Thereby, the heat storage body 1 is discharged from the accommodation space 2.

(Effect of this embodiment)
The heat storage body 1 of this embodiment has high strength, thermal shock resistance, and heat exchange efficiency because the axial length (L), outer diameter (d _O ), and inner diameter (d _I ) are included in predetermined ranges. In addition, it exhibits the effect of becoming a heat storage body excellent in assemblability.

  Furthermore, the heat storage body 1 of this embodiment can be significantly reduced in weight as compared with a conventional ball. According to this configuration, as shown in FIG. 3, even if the column 3 extending in the axial direction is filled, the weight applied to the bottom plate 30 can be reduced, and a large load is applied to the column 3 (the bottom plate 30 and the heat storage burner). Damage caused by this can be suppressed.

[Embodiment 2]
The heat storage body 1 of this embodiment is the same as that of Embodiment 1 except that the outer shape is different. The heat storage body 1 of this embodiment is shown in a perspective view in FIG. 4 and a cross-sectional view in FIG. FIG. 4 is a perspective view showing the heat storage body 1 as in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG.

As shown in FIGS. 4 to 5, the heat storage body 1 of this embodiment is formed such that one end surface 1 a in the cylindrical axial direction (the upper end surface in FIG. 4) is inclined with respect to the axial direction. Yes. In the heat storage body 1 of this embodiment, the other end face 1b in the axial direction is formed perpendicular to the axial direction.
When at least one end face in the axial direction is inclined as in the heat storage body 1 of the present embodiment, the axial length (L) is the longest distance of the axial length of the heat storage body 1 ( L ₁ ) and the shortest distance (L _s ) and the average distance (L _av ).
The heat storage element 1 of this embodiment is different only in the outer peripheral shape (angle of the end face), and exhibits the same effect as that of the first embodiment.

  Furthermore, the heat storage body 1 according to the present embodiment is formed such that one end face 1a in the axial direction is inclined with respect to the axial direction, so that it contacts the one end face 1a when poured into the column 3 and filled. Another heat storage body 1 is not arranged. That is, the effect that it is surely arranged at random is exhibited.

[Embodiment 3]
The heat storage body 1 of this form is the same as that of Embodiments 1-2 except that the external shape differs. The heat storage body 1 of this embodiment is shown in a perspective view in FIG. 6 and a cross-sectional view in FIG. FIG. 6 is a perspective view showing the heat storage body 1 as in FIGS. 7 is a cross-sectional view taken along line VII-VII in FIG.

As shown in FIGS. 6 to 7, the heat storage body 1 of this embodiment is formed such that one end surface 1 a in the cylindrical axial direction and the other end surface 1 b are inclined with respect to the axial direction. The inclination angle α of one end face 1a and the inclination angle β of the other end face 1b are different (α ≠ β).
As defined in the second embodiment, the axial length (L) of the heat accumulator 1 is the longest distance (L ₁ ) and the shortest distance (L _s ) of the axial length of the heat accumulator 1. , The average distance (L _av ).

  The heat storage body 1 of this embodiment is different only in the outer peripheral shape, and exhibits the same effects as those of the first and second embodiments. The heat storage body 1 of the present embodiment is formed such that both end faces 1a and 1b in the axial direction are inclined and can be filled more randomly.

  Furthermore, the heat storage body 1 of this embodiment is formed such that one end surface 1a and the other end surface 1b in the axial direction are inclined at different inclination angles (α ≠ β) with respect to the axial direction. The two inclination angles α and β are also in a relationship of α ≠ 180−β. According to this configuration, when the heat storage body 1 is poured into the column 3 and filled, another heat storage body 1 that comes into contact with one end surface 1a is not arranged. Even if the end surfaces are arranged so that they are in contact with each other, the inclined end surfaces are guided to each other, and the effect of being arranged more reliably at random is exhibited.

[Embodiment 4]
The heat storage body 1 of this embodiment is the same as that of Embodiment 1 except that the outer shape is different. The heat storage body 1 of this embodiment is shown in a sectional view in FIG. FIG. 8 is a cross-sectional view showing a cross section at the axial center of the heat accumulator 1 as in FIG. 2.

  As shown in FIG. 8, the heat storage body 1 of this embodiment is formed in a cylindrical shape whose outer diameter in the radial direction changes. The heat storage body 1 of this embodiment has a cylindrical shape with a substantially tall outer shape so that the outer diameter of the central portion in the axial direction is the largest. In the heat storage body 1 of this embodiment, the inner diameter also changes in accordance with the change in the outer diameter. That is, as shown in FIG. 8, the heat storage body 1 of this embodiment has a substantially constant radial thickness.

Regardless of the position in the axial direction, the heat storage body 1 of the present embodiment includes an axial length (L), an outer diameter (d _O ), and an inner diameter (d _I ) within a predetermined range. That is, the outer diameter (d _O ) and the inner diameter (d _I ) at the axial end portions (end surfaces 1a, 1b) and the central portion are both within the range specified in the first embodiment. Specifically, the outer diameter (d _O ) and the inner diameter (d _I ) are included in a predetermined range in a vertical cross section at a position in an arbitrary axial direction.
The heat storage body 1 of this embodiment is different only in the outer peripheral shape, and exhibits the same effect as that of the first embodiment.

[Embodiment 5]
The heat storage body 1 of the present embodiment is the same as that of the fourth embodiment except that the radial thickness is different. The heat storage body 1 of this embodiment is shown in a sectional view in FIG. FIG. 9 is a cross-sectional view showing a cross section at the axial center of the heat accumulator 1 as in FIG. 8.

As shown in FIG. 9, the heat storage body 1 of this embodiment is formed so that the inner diameter in the radial direction is constant. Moreover, the heat storage body 1 of this embodiment has a substantially cylindrical outer shape so that the outer diameter of the central portion in the axial direction is the largest. That is, the heat storage body 1 of this embodiment is formed such that the thickness is thin at both ends in the axial direction, and the thickness of the central portion in the axial direction is the thickest.
In the heat storage body 1 of this embodiment, the outer diameter (d _O ) and the inner diameter (d _I ) at the axial end portions (end faces 1a, 1b) and the central portion are both within the range specified in the first embodiment. Yes. Specifically, as in the fourth embodiment, the outer diameter (d _O ) and the inner diameter (d _I ) are included in a predetermined range in a vertical cross section at a position in an arbitrary axial direction.
The heat storage body 1 of this embodiment is the same as that of Embodiment 1 except that the thickness is not constant, and exhibits the same effect.

[Embodiment 6]
The heat storage body 1 of this embodiment is the same as that of Embodiment 1 except that the outer shape is different. The heat storage body 1 of this embodiment is shown in FIG. 10 in a cross section perpendicular to the axial direction.
As shown in FIG. 10, the heat storage body 1 of the present embodiment has an annular cross-sectional cylindrical shape with a part cut. In the heat storage element 1 of this embodiment, the outer diameter (d _O ) and the inner diameter (d _I ) correspond to the diameters of the outer circumference and the inner circumference of the annular shape when not cut.
The heat storage body 1 of this embodiment is different only in the outer peripheral shape, and exhibits the same effect as that of the first embodiment.

[Embodiment 7]
The heat storage body 1 of this embodiment is the same as that of Embodiment 1 except that the outer shape is different. The heat storage body 1 of this embodiment is shown in FIG. 11 in a cross section perpendicular to the axial direction.
As shown in FIG. 11, the heat storage body 1 of this embodiment has a cylindrical shape (hexagonal cylinder) having a hexagonal cross-sectional shape. In the heat storage body 1 of the present embodiment, the outer diameter (d _O ) corresponds to the distance of the longest portion of the imaginary line passing through the center of gravity (axial center) of the cross section, and the hexagonal symmetrical position This is the distance on the line passing through the corner. Further, the inner diameter (d _I ) corresponds to the distance of the inner peripheral surface in the virtual line for obtaining the outer diameter (d _O ). In FIG. 11, the imaginary line is indicated by a broken line passing through the axis.
The heat storage body 1 of this embodiment is different only in the outer peripheral shape, and exhibits the same effect as that of the first embodiment.

[Modification of Embodiment 7]
In Embodiment 1, the cylindrical heat storage body 1 is shown, and in Embodiment 7, the hexagonal tubular heat storage body 1 is shown, but it is not limited to these shapes. For example, it may be a polygon such as a triangle or a rectangle (square or rectangle). The polygon is preferably a regular polygon.

Hereinafter, the present invention will be described using examples. The thermal storage body 1 of Embodiment 1 was manufactured as an Example of this invention.
Example 1
This example is a cylindrical heat accumulator 1 having an outer diameter (d _O ): 8.0 mm, an inner diameter (d _I ): 4.5 mm, and an axial length (L): 8.0 mm. Regenerator 1 of this embodiment, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) is 1.00, the outer diameter _{(d O)} and an inner diameter _{(d I} ) And (d _O / d _I ) is 1.78.
The heat storage body 1 of this example is made of porous alumina ceramics having a porosity of 10%.

(Example 2)
This example is a cylindrical heat accumulator 1 having an outer diameter (d _O ): 10.0 mm, an inner diameter (d _I ): 4.0 mm, and an axial length (L): 10.0 mm. Regenerator 1 of this embodiment, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) is 1.00, the outer diameter _{(d O)} and an inner diameter _{(d I} ) (D _O / d _I ) is 2.50.
The heat storage body 1 of this example is made of porous silicon carbide ceramics having a porosity of 35%.

(Comparative Example 1)
This example is a heat storage body made of a conventional ceramic ball. The heat storage body of this example has a ball shape of φ9.5 mm.
The heat storage body 1 of this example is made of the same alumina ceramic as in the first embodiment.

(Comparative Example 2)
This example is a cylindrical heat accumulator 1 having an outer diameter (d _O ): 8.0 mm, an inner diameter (d _I ): 4.5 mm, and an axial length (L): 15.0 mm. Regenerator 1 of this embodiment, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) is 1.88, the outer diameter _{(d O)} and an inner diameter _{(d I} ) And (d _O / d _I ) is 1.78.
The heat storage body 1 of this example is made of the same alumina ceramic as in the first embodiment.

(Example 3)
This example is a cylindrical heat accumulator 1 having an outer diameter (d _O ): 8.0 mm, an inner diameter (d _I ): 7.0 mm, and an axial length (L): 8.0 mm. Regenerator 1 of this embodiment, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) is 1.00, the outer diameter _{(d O)} and an inner diameter _{(d I} )) (D _O / d _I ) is 1.14.
The heat storage body 1 of this example is made of porous alumina ceramics having a porosity of 5%.

Example 4
This example is a cylindrical heat accumulator 1 having an outer diameter (d _O ): 8.0 mm, an inner diameter (d _I ): 1.5 mm, and an axial length (L): 8.0 mm. Regenerator 1 of this embodiment, the ratio of the axial length (L) and outer diameter _{(d O) (L / d} O) is 1.00, the outer diameter _{(d O)} and an inner diameter _{(d I} ) (D _O / d _I ) is 5.33.
The heat storage body 1 of this example is made of the same alumina ceramic as in the first embodiment.

[Evaluation]
About the thermal storage body 1 of said each example, it assembled | attached to the thermal storage type burner 4, it combusted, and the thermal storage body was evaluated.

(Regenerative burner)
The heat storage burner 4 to which the heat storage body 1 is assembled has a configuration schematically shown in FIG.
The regenerative burner 4 includes two burners 4 (4A, 4B) facing each other in the furnace body 5, as shown in FIG. The two burners 4 (4A, 4B) have the same configuration and are given the same reference numerals.

  The regenerative burner 4 has a burner section 40 having a fuel injection port 41 for injecting fuel into the furnace body 5, and a supply / exhaust passage for supplying combustion air from an intake pipe and exhausting combustion exhaust gas (exhaust gas) from the exhaust pipe And an intake / exhaust port 44 for supplying combustion air to the furnace body 5 and exhausting combustion exhaust gas (exhaust gas) from the furnace body 5.

The burner unit 40 has a fuel injection port 41 for injecting fuel (combustion gas). The fuel (combustion gas) injected from the fuel injection port 41 generates combustion and is used for heating the inside of the furnace body 5.
The air supply / exhaust section 42 has a supply / exhaust passage 43 that supplies combustion air from an air supply pipe and exhausts combustion exhaust gas from the exhaust pipe.

  The intake / exhaust section 42 has a heat storage chamber 45 that houses the heat storage body 1 in its path. The heat storage chamber 45 corresponds to the accommodation space 2 shown in FIG. The heat storage chamber 45 is partitioned into a main body 46 and a bottom plate 47.

The main body 46 corresponds to the main body 30 of the column 3. The main body portion 46 includes an input portion 48 and a discharge portion 49 corresponding to the input portion 33 and the discharge portion 34 of the column 3. The charging section 48 is provided in the main body 46 at the upper part of the heat storage chamber 45 (vertically above the bottom plate 47 in the wall section that defines the heat storage chamber 45). The discharge part 49 is provided in the lower part of the heat storage chamber 45 (the side part of the bottom plate 47 among the wall parts that define the heat storage chamber 45).
The bottom plate 47 corresponds to the bottom plate 31 of the column 3 and is held (placed) in a state where the heat storage body 1 is not fixed to the upper portion.

(Assembling to a heat storage burner)
The heat storage chamber 45 of the heat storage burner 4 used for this evaluation has an axial length of 10 cm and an internal volume of 4 L.
The heat storage body 1 of each example is filled (assembled) so as to flow into the heat storage chamber 45 from the input portion 48 in a state where the discharge portion 49 is closed. The total mass of the heat storage body 1 filled in the heat storage chamber 45 was measured and shown in Table 1. The total mass of the heat storage body 1 is the mass of the heat storage body 1 having an apparent volume of 4L.

No damage was confirmed in any of the heat storage bodies 1 of each example after filling. That is, it was confirmed that the heat storage body 1 of each example had sufficient strength against the impact when pouring.
Moreover, since the thermal storage body 1 of each example was able to be filled so that it might flow into the thermal storage chamber 45 of the thermal storage type burner 4, it has confirmed that it was excellent also in the assembly property.

(Combustion of regenerative burner)
The regenerative burner 4 was operated so that the furnace temperature was 1300 ° C.
Specifically, the heat storage burner 4A supplies combustion air from the air supply pipe to the heat storage chamber 45 via the air supply / exhaust section 42 (intake pipe). The combustion air passes through the intake / exhaust port 44 after contacting the heat storage body 1 in the heat storage chamber 45 and is supplied into the furnace body 5. At the same time, fuel (combustion gas) is injected into the furnace body 5 from the fuel injection port 41 of the burner section 40, and combustion is performed.

At this time, in the regenerative burner 4B, fuel (combustion gas) is not injected from the burner portion 40. Then, combustion exhaust gas (exhaust gas) of the furnace body 5 is supplied to the heat storage chamber 45 through the intake / exhaust port 44. The exhaust gas is exhausted through the air supply / exhaust section 42 (exhaust pipe) after contacting the heat storage body 1 in the heat storage chamber 45. When the heat storage body 1 and the exhaust gas come into contact with each other in the heat storage chamber 45, the heat storage body 1 is heated and stored by the exhaust gas.
After a predetermined time has elapsed, the functions of the heat storage burner 4A and the heat storage burner 4B are switched.
Specifically, the heat storage burner 4A exhausts the exhaust gas in the furnace body 5 in the same manner as the heat storage burner 4B.

The regenerative burner 4B performs combustion in the furnace body 5 in the same manner as the regenerative burner 4A. At this time, in the heat storage type burner 4B, the combustion air supplied to the heat storage chamber 45 is brought into contact with the heat storage body 1 previously heated via the air supply / exhaust section 42 (intake pipe). By this contact, the combustion air is heated (heat exchanged), and the heated combustion air is supplied into the furnace body 5. And fuel (combustion gas) is injected from the fuel injection port 41 of the burner part 40, and combustion is performed.
After a predetermined time has elapsed, the functions of the heat storage burner 4A and the heat storage burner 4B are switched.
In this evaluation, this burner replacement is repeated, and combustion in the regenerative burner 4 is performed.

  In this evaluation, the exhaust gas flowing into the heat storage chamber 45 is 1300 ° C. The combustion air flowing into the heat storage chamber 45 is at room temperature. The gas flowing into the heat storage chamber 43 was switched every 15 seconds.

  When the temperature of the exhaust gas is stabilized, among the heat storage elements 1 filled in the heat storage chamber 45, the temperature of the heat storage element 1 at a position in contact with the bottom plate 47 (low temperature part temperature) and the topmost part closest to the furnace body 5 The temperature (high temperature part temperature) of the heat storage body 1 positioned was measured and shown in Table 1.

Further, the temperature of exhaust gas discharged from the heat storage chamber 45 through the bottom plate 47 was measured and shown in Table 1.
At the same time, the pressure of each gas passing through the heat storage chamber 45 was measured, and the pressure loss when the gas passed through the heat storage chamber 45 was determined. The obtained pressure loss is shown together in Table 1.

  In addition, when the heat storage burner 4 was burned, the heat storage body of Comparative Example 1 was confirmed to be broken or broken. This breakage is a breakage caused by volume change (thermal expansion / contraction) caused by an increase in temperature difference (partial temperature difference) between the surface and the inside (center portion).

  As shown in Table 1, in Comparative Example 1 which is a ball-shaped heat storage body, the total mass is as heavy as 9.0 kg. On the other hand, the heat storage body 1 of each Example is cylindrical shape, the total mass is lighter than the comparative example 1, and the workability | operativity of an assembly is improving. Moreover, since the heat storage body 1 of each Example is lightweight, the load added to the baseplate 47 (total mass of the heat storage body 1) is reducing, and the effect which can reduce the load of a heat storage type burner is exhibited.

  In particular, the heat storage body 1 of Example 2 is made of silicon carbide ceramics, so that it is significantly lighter than heat storage bodies made of other alumina ceramics.

Further, as shown in Table 1, the length in the axial direction (L) and outer diameter _{(d O)} and the ratio (L / _{d O)} is 1.88 and the heat storage of large Comparative Example 2, the exhaust gas temperature And pressure loss is high. The exhaust temperature and pressure loss of the heat storage body of Comparative Example 2 are worse than those of Comparative Example 1. On the other hand, the heat storage body 1 of each Example whose ratio (L / d 2 _{O 3} ) is 1.00 has lower exhaust temperature and pressure loss than Comparative Example 2 (and Comparative Example 1). This is considered to be because the heat storage body of Comparative Example 2 has a long-axis cylindrical shape and is periodically arranged in the accommodation space 2 (heat storage chamber).

In the heat storage body 1 of each Example, it can be confirmed that the pressure loss decreases as the ratio (d _O / d _I ) between the outer diameter (d _O ) and the inner diameter (d _I ) decreases. Also, as the ratio _(d O _/ d _I) increases, the total mass of the heat accumulation element 1 can be confirmed to be increased.

As described in detail above, the heat storage body 1 of each example in which the ratio (L / d _O ) between the axial length (L) and the outer diameter (d _O ) is within a predetermined range is: It is a heat storage body that has high thermal shock resistance and high efficiency of heat exchange and is excellent in assembling.

1: Heat storage body 2: Housing space 3: Column 30: Body part 31: Bottom plate 32: Top plate 4: Thermal storage burner 40: Burner part 41: Fuel injection port 42: Intake / exhaust part 43: Intake / exhaust passage 44: Heat storage chamber 45: Thermal storage chamber 46: Body part 47: Bottom plate 48: Input part 49: Discharge part

Claims (4)

A heat storage body (1) used in a heat storage burner (4) for exchanging heat by alternately circulating exhaust gas heated by combustion of a burner and gas supplied for combustion of the burner,
A heat storage element (1) comprising a cylindrical ceramic having a ratio (L / d _O ) between an axial length (L) and an outer diameter (d _O ) of greater than 0.8 and less than 1.2 ). Cylindrical heat storage body, an outer diameter _{(d O)} and an inner diameter _{(d I)} and the ratio _(d O / d _I) is heat accumulator according to claim 1, wherein less than greater than 1.2 4.   The heat storage body according to any one of claims 1 to 2, comprising a silicon carbide ceramic.   The heat storage body according to any one of claims 1 to 3, wherein at least one of the end faces in the axial direction is formed to be inclined with respect to the axial direction.

Images