Defatting furnace exhaust gas combustion device and defatting system

Abstract

The present application provides a kind of waste gas combustion device for defatting furnace and defatting system, and all aspects such as consumption power, space, manufacturing cost, operating cost are excellent. The catalyst (33) is set to contain porous alumina ceramic of platinum, and the catalyst (33) burns the waste gas generated in defatting furnace (1).

Description

TECHNICAL FIELD

[0001] The present application relates to an exhaust gas combustion device or the like for a debinding furnace for performing debinding treatment on a treatment object such as a ceramic material. BACKGROUND

[0002] In the past, in a debinding process in which a treatment object such as a metal or a ceramic is subjected to heat treatment to remove a binder component (organic substance) in the treatment object, an atmospheric pressure gas debinding furnace or a superheated steam debinding furnace is used.

[0003] In the debinding process, the binder is decomposed and removed by heating the treatment object, but volatile organic compounds (VOC) are contained in the exhaust gas generated at this time, and thus, in order not to directly release the VOC into the atmosphere, an exhaust gas combustion device is attached to the debinding furnace, and the exhaust gas is combusted using the exhaust gas combustion device.

[0004] In the exhaust gas combustion device, there are a direct combustion method in which the exhaust gas is directly heated and combusted, or a catalytic combustion method in which the exhaust gas is decomposed (combusted) using a catalyst (see Patent Literature 1), and the like.

[0005] In addition, in the case of the direct combustion method, the debinding process takes several tens of hours, and it is necessary to heat to about 800°C at which the VOC is combusted, and thus the power consumption of the exhaust gas combustion device that operates during this time becomes very large. Therefore, since efforts have been made in recent years to achieve carbon neutrality, the exhaust gas combustion device of the direct combustion method has difficulty in sufficiently responding to the requirement for reducing power consumption required by the entire manufacturing device.

[0006] Further, in the case of the direct combustion method, in terms of the principle of heating the exhaust gas using a heater, the number of parts increases, and a sufficient space for combustion is required, and the entire exhaust gas combustion device and debinding furnace become large.

[0007] On the other hand, in the case of the catalytic combustion method, if the catalyst is heated to about 400°C, the VOC is combusted due to the self-ignition (catalysis) action, and thus reduction of power consumption can be achieved compared to the direct combustion method.

[0008] However, if the concentration of the exhaust gas is too high, the temperature of the catalyst becomes high due to self-ignition, and thermal degradation occurs, and thus it is necessary to reduce (dilute) the concentration of the exhaust gas for use. In addition, a large amount of dilution gas is required for this, the total gas flow rate increases, and the running cost increases.

[0009] In recent years, there has also been a defatting furnace using superheated steam to shorten the defatting time, but the exhaust gas concentration becomes high to the extent that the defatting process time is shortened, and thus a direct combustion method or a catalytic combustion method using a large amount of gas is used in the exhaust gas combustion device, and the resulting undesirable conditions become significant and become a limitation of the superheated steam type defatting furnace.

[0010] [Related Art Documents]

[0011] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Laid-Open No. 8-194093 SUMMARY

[0013] [Problems to be Solved by the Invention]

[0014] The present invention is to solve the above problems at once, and overturns the conventional wisdom in the field that exhaust gas in the defatting furnace needs to be diluted, and has epoch-making significance.

[0015] [Technical Means for Solving the Problems]

[0016] That is, the exhaust gas combustion device for a defatting furnace of the present invention uses a catalyst to combust the exhaust gas generated in the defatting furnace, and the catalyst is a porous alumina ceramic containing platinum.

[0017] The exhaust gas combustion device for a defatting furnace of the present invention uses a catalyst to combust the exhaust gas generated in the defatting furnace, and the catalyst is in a granular form, and the catalyst is laid in a layer in a burner through which the exhaust gas passes, and the catalyst layer laid in a layer in the burner is provided with a plurality of stages at intervals.

[0018] The defatting system of the present invention includes a defatting furnace, and the exhaust gas combustion device for the defatting furnace.

[0019] The catalyst is hardly subject to thermal degradation at high temperatures (e.g., 1100°C), and thus high concentration exhaust gas generated in the defatting process can be combusted without dilution.

[0020] Further, when the exhaust gas containing organic compounds is decomposed using the catalyst, a decomposition heat of about 100°C is generated at a gas concentration of 100 ppm. Even in the treatment of substances that are not easily oxidized at high temperatures, the catalyst temperature can be set to a high temperature by absorbing the reaction heat in the porous alumina ceramic body, and the gas decomposition can be performed. Thus, without actively setting the catalyst temperature to a high temperature, the exhaust gas treatment can be performed while maintaining the control at a relatively low temperature (200°C to 400°C), and the power consumption can be reduced.

[0021] Thus, the disadvantages of the conventional catalytic combustion type exhaust gas combustion device requiring a large amount of dilution gas can be eliminated, the gas used by the device as a whole can be reduced, and the operation cost can be lowered.

[0022] In addition, the advantages of the catalytic combustion type, i.e., low power consumption, space saving, and low manufacturing cost, etc., can be further promoted relative to the direct combustion type.

[0023] Furthermore, such effects become apparent when combined with a superheated steam degreasing treatment.

[0024] [Effects of the Invention]

[0025] According to the above structure, the disadvantages of the conventional catalytic combustion type exhaust gas combustion device can be solved, the advantages thereof can be exhibited, and an exhaust gas combustion device for a degreasing furnace that is excellent in all of power consumption, space, manufacturing cost, operation cost, etc., can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic view of a degreasing system as a whole according to an embodiment of the present invention.

[0027] Figure 2 is a front view of an exhaust gas combustion device according to the embodiment.

[0028] Figure 3 is a perspective view showing the internal structure of the exhaust gas combustion device according to the embodiment.

[0029] Figure 4 is a perspective view showing a catalyst housing body according to the embodiment.

[0030] Figure 5 is a view showing the internal structure of the exhaust gas combustion device according to the embodiment as viewed from the front.

[0031] [Explanation of Symbols]

[0032] 1: Degreasing furnace

[0033] 2: Superheated steam generating device

[0034] 3: Exhaust gas combustion device

[0035] 31: Burner

[0036] 31a: Inlet port

[0037] 31b: Outlet port

[0038] 31c: Catalyst placement area

[0039] 32: Heater

[0040] 33: Catalyst

[0041] 33A: Catalyst layer

[0042] 34: Catalyst containment

[0043] 100: Degreasing System

[0044] 311: Cylindrical section

[0045] 312: Flange portion

[0046] P: Space layer

[0047] W: Processing objects Detailed Implementation

[0048] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0049] The degreasing system 100 of this embodiment is as follows: Figure 1 As shown in the schematic overall diagram, it includes: a degreasing furnace 1 containing the object to be processed, W; a superheated steam generating device 2 supplying superheated steam as degreasing gas into the degreasing furnace 1; and an exhaust gas combustion device 3 introducing and burning the exhaust gas generated from the object to be processed, W, by using the superheated steam for degreasing treatment.

[0050] The following description focuses on the exhaust gas combustion device 3.

[0051] The waste gas combustion device 3, as described above Figure 2 , Figure 3 As shown, it includes a cylindrical burner 31, a heater 32 for heating the burner 31, and a catalyst 33 housed within the burner 31.

[0052] Each part is described in detail.

[0053] The burner 31 includes a cylindrical portion 311 and flange portions 312 that block both ends of the cylindrical portion 311. An inlet port 31a for introducing exhaust gas is provided on the side circumferential surface of one end of the cylindrical portion 311, and an outlet port 31b for discharging the exhaust gas (treated gas) that has passed through the cylindrical portion 311 and undergone combustion is provided on the side circumferential surface of the other end. Furthermore, the burner 31 is vertically arranged such that the inlet port 31a is the lower end and the outlet port 31b is the upper end.

[0054] Furthermore, between the inlet port 31a and the outlet port 31b of the cylindrical portion 311, such as Figure 3 As shown, two catalyst placement areas 31c are arranged axially away from each other. Furthermore, in each catalyst placement area 31c, a catalyst housing 34 is installed to house the catalyst 33. Figure 3The catalyst 33 and the catalyst housing 34 are omitted.

[0055] The catalyst housing 34 is as shown in FIG. 4, and is a cylindrical shape with one end face (upper end face) open, formed of a material (here, a metal mesh) having a plurality of holes of a size that allows gas to pass through but retains the catalyst, and is disposed fitted to the inner face of the cylindrical portion 311. Figure 4

[0056] The heater 32 is a wire shape having flexibility, and is provided in a spiral shape with gaps open at the upper end and / or the lower end of each catalyst setting area 31c.

[0057] The catalyst 33 is a granular shape (here, a spherical shape) in which porous alumina ceramic supports platinum as a catalyst body, and has the following specifications.

[0058] Material: Alumina

[0059] Main component: Al203 is 90% or more

[0060] Bulk specific gravity: 1.52 g / cm 3

[0061] Water absorption: 35% ± 5%

[0062] Apparent porosity: 55% ± 5%

[0063] Specific surface area: 8 m 3 / g

[0064] Maximum use temperature: 1100°C

[0065] Ball diameter: 5 mm

[0066] The catalyst 33 is as shown in FIG. 5, and is laid in a manner to become a catalyst layer 33A having a thickness of 20 mm to 25 mm in each catalyst housing 34 described above. Figure 5

[0067] Thus, according to the exhaust gas combustion device 3 thus configured, the maximum use temperature of the catalyst 33 is extremely high (here, 1100°C), and thus even if the catalyst 33 becomes high temperature due to the self-ignition of the exhaust gas, which exceeds the heating temperature of the heater 32 (here, 400°C), it can maintain its performance without thermal degradation. Therefore, even if the exhaust gas discharged in the degreasing process is exhaust gas having a high VOC concentration, such as 10,000 ppm or more, it can be combusted without dilution.

[0068] Thus, it is possible to reasonably eliminate the point that a large amount of dilution gas is required, which is a disadvantage of the conventional catalytic combustion method, and the point that the operating cost increases due to this.

[0069] ​​In particular, in the present embodiment, the use of superheated steam for degreasing results in a reduction in the degreasing time, and as a result, the exhaust gas concentration tends to be high. In the past, either a large-scale combustor based on a direct combustion method or a catalytic combustion method using a large amount of dilution gas had to be used, but in the exhaust gas combustor of the present embodiment, although it is a catalytic combustion method, dilution gas is not required, and the advantages of downsizing or low operating costs can be ensured, and thus the effects become particularly remarkable when combined with superheated steam degreasing.

[0070] Furthermore, the catalytic combustion method can be used in a rational manner, and thus the power consumption during operation can be drastically reduced compared to the exhaust gas combustor of the direct combustion method, and the space and manufacturing costs can also be greatly reduced.

[0071] According to the trial calculations performed by the inventors, it was confirmed that, compared to the exhaust gas combustor 3 of the direct combustion method, the power consumption can be reduced by about 10 to 20%, the space can be reduced by about 80%, and the manufacturing costs can be reduced by about 20%, and the like.

[0072] Furthermore, in the case where the catalyst layer is one layer, sometimes the exhaust gas is concentrated only in a portion where it easily flows during exhaust gas combustion, and catalytic combustion is generated only by the catalyst 33 in contact with the gas path, and further improvement in combustion efficiency cannot be achieved, but in the present embodiment, the catalyst layer 33A is distanced from the catalyst layer 33A, and a space layer P (shown in FIG. 2) is provided therebetween, and thus the gas diffusion effect of the space layer P can be exerted, and the exhaust gas path is uniformly formed throughout the catalyst layer 33A, and thus catalytic combustion can be performed with high efficiency by the catalyst 33 as a whole. Figure 3

[0073] The effects can also be promoted by providing the exhaust gas introduction port 31a on the side peripheral surface of the combustor 31. That is, the exhaust gas is introduced from a direction (a vertical direction) different from the gas flow in the combustor 31, and thus turbulent flow is easily generated at the time of introduction, and thus the exhaust gas flows thoroughly in the catalyst layer 33A in the initial stage, and in this respect, high-efficiency catalytic combustion is also promoted.

[0074] If the features of the exhaust gas combustor 3 described above are summarized, the following is obtained.

[0075] (1) The exhaust gas combustor 3 for a degreasing furnace, which combusts the exhaust gas generated in the degreasing furnace 1 using a catalyst 33, is a porous alumina ceramic containing platinum.

[0076] If so, as described above, an exhaust gas combustor 3 for a degreasing furnace that is excellent in all aspects of power consumption, space, manufacturing costs, operating costs, and the like can be provided.

[0077] ​(2) The catalyst 33 is in a granular form, and the catalyst 33 is laid in a layered manner in the catalyst housing 34 in the combustor 31 through which the exhaust gas passes. The catalyst housing 34 is a metal mesh.

[0078] If so, the exhaust gas reliably contacts the catalyst 33, and thus the combustion efficiency can be improved.

[0079] (3) The catalyst housing is formed of a raw material having a plurality of holes of a size that allows the exhaust gas to pass through but retains the catalyst, and the catalyst is laid in a layered manner in the catalyst housing.

[0080] (4) The catalyst layers 33A laid in a layered manner in the combustor 31 are provided in a plurality of stages with spaces therebetween.

[0081] If so, the exhaust gas diffuses in the spaces between the catalyst layers 33A, and the exhaust gas path is formed uniformly throughout the catalyst layers 33A, and thus the catalytic combustion can be performed more efficiently overall using the catalyst 33.

[0082] (5) In order to improve the catalytic efficiency, the bulk specific gravity of the catalyst 33 is preferably 0.5 g / cm 3 ~ 3 g / cm 3 , more preferably 1 g / cm 3 ~ 2 g / cm 3 , and even more preferably 1.5 g / cm

[0083] (6) The apparent porosity of the catalyst 33 is preferably 30% ~ 60%, more preferably 50% ~ 60%, and even more preferably 55% ~ 60%.

[0084] (7) The pore diameter of the catalyst 33 is preferably 0.1 μm ~ 5 μm, more preferably 1 μm ~ 3 μm, and even more preferably 1.5 μm ~ 2 μm.

[0085] (8) The diameter of the catalyst 33 is preferably 1 mm ~ 10 mm, more preferably 3 mm ~ 7 mm, and even more preferably 4 mm ~ 6 mm.

[0086] (9) The exhaust gas combustion device for a degreasing furnace uses a catalyst to combust the exhaust gas generated in the degreasing furnace, the catalyst is in a granular form, and the catalyst is laid in a layered manner in the combustor through which the exhaust gas passes, and the catalyst layers laid in a layered manner in the combustor are provided in a plurality of stages with spaces therebetween.

[0087] If so, the exhaust gas diffuses in the spaces between the catalyst layers 33A, and the exhaust gas path is formed uniformly throughout the catalyst layers 33A, and thus the catalytic combustion can be performed more efficiently overall using the catalyst 33.

[0088] (10) The effect of the present embodiment becomes more significant if the degreasing furnace 1 uses superheated steam to degrease the object to be treated W.

[0089] Further, the present application is not limited to the described embodiments.

[0090] For example, the catalyst is not limited to a spherical shape, but can be a deformed shape as long as gaps are created between the catalysts when laid. The catalyst layer is not limited to two layers, but can be one layer or three or more layers. The degreasing gas is not limited to superheated steam, but can be N2 gas. The exhaust gas combustion device 3 of the present application can be used in multiple groups.

[0091] The shape of the exhaust gas combustion device is not limited to a cylindrical shape, but can be a block shape or the like.

[0092] Further, the present application is not limited to the described embodiments, but can be variously modified within the scope of the gist thereof.

Claims

1. A defatting furnace exhaust gas combustion device characterized by comprising: a porous alumina ceramic containing platinum is used as a catalyst for burning exhaust gas generated in a degreasing furnace, the catalyst is in a granular form and is laid in a layered manner in a burner through which the exhaust gas passes, the catalyst layers laid in a layered manner in the burner are provided in a plurality of stages with the catalyst in the catalyst layers in the plurality of stages being a porous alumina ceramic containing platinum, and the space layers have a gas diffusion function of suppressing a decrease in combustion efficiency due to concentration of the exhaust gas in a part of the catalyst layers while forming exhaust gas paths uniformly in the entire catalyst layers.

2. The off-gas combustion device for a degreasing furnace according to claim 1, wherein comprising: a catalyst housing body formed of a raw material having a plurality of holes through which exhaust gas passes but which retain a pore diameter of the catalyst, the catalyst being laid in a layered manner in the catalyst housing body.

3. The off-gas combustion device for a degreasing furnace according to claim 1, wherein The bulk specific gravity of the catalyst is 0.5 g / cm 3 ~ 3 g / cm 3 .

4. The off-gas combustion device for a degreasing furnace according to claim 1, wherein the apparent porosity of the catalyst is 30% to 60%.

5. The off-gas combustion device for a degreasing furnace according to claim 1, wherein the pore diameter of the catalyst is 0.1 μm to 5 μm.

6. The off-gas combustion device for a degreasing furnace according to claim 1, wherein the diameter of the catalyst is 1 mm to 10 mm.

7. An exhaust gas burning device for a degreasing furnace, which uses a catalyst for burning exhaust gas generated in a superheated steam degreasing furnace, the catalyst is a porous alumina ceramic containing platinum in a granular form and is laid in a layered manner in a burner through which the exhaust gas passes, the catalyst layers laid in a layered manner in the burner are provided in a plurality of stages with spaces, the exhaust gas burning device for the degreasing furnace includes a heater provided at each of upper and / or lower ends of the catalyst layers in the plurality of stages.

8. A defatting system comprising: a degreasing furnace; and the exhaust gas burning device for the degreasing furnace as claimed in any one of claims 1 to 7.

9. The debinding system of claim 8, wherein, the degreasing furnace uses superheated steam to degrease a treatment target.

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