JPH1089654A - Method and apparatus for deodorizing exhaust gas of atmosphere baking furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently deodorize at low cost while maintaining atmosphere in a baking furnace by a simple apparatus by directly deodorizing odor gas by combustion of a burner and further passing it through a red-heated metal carrier. SOLUTION: Combustion gas is burnt by a ring burner 15, and gases in a collecting duct 12 and combustion hood 14 are sucked in an exhaust direction by driving a blower 18. Odor gas A is sucked to the duct 12 together with the atmosphere B, and introduced to a ring of the burner 15. Combustion gas such as LPG is formed in a flame 23 in the burner 15. A metal carrier 17 disposed in the burner 15 is heated by the flame 23 to be red-heated. Odor gas A such as acetaldehyde introduced to the ring of the burner 15 is burnt and decomposed by the flame 23. Further, it is brought into contact with the high temperature carrier 17 (e.g. stainless steel or high nickel-chromium steel), burnt, decomposed, changed to carbon dioxide, hydrogen and the like, and exhausted via an exhaust cylinder 19 in the direction indicated by an arrow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for deodorizing exhaust gas from an atmosphere firing furnace. More specifically, the present invention relates to an exhaust gas deodorizing method and a deodorizing apparatus for an atmosphere firing furnace for deodorizing odor gas generated in a firing process of ceramics such as ferrite by thermal decomposition or combustion decomposition.

[0002]

2. Description of the Related Art In the production of ceramic sintered bodies such as ferrite, a method of firing raw material powder in an atmosphere firing furnace is generally used. That is, first, an organic binder such as polyvinyl alcohol is added as a binder to the ceramic powder as a raw material. Next, the raw material powder is processed into a predetermined shape by a granulation step by a spray dry method or a molding step by a press method. Further, the powder processed into a predetermined shape is fired at a high temperature in an inert atmosphere using an atmosphere firing furnace to obtain a ceramic sintered body having a granular or predetermined shape.

Here, the temperature required for sintering differs depending on the material and the like. Taking the case of ferrite as an example, when sintering low-loss ferrite as a magnetic material, the sintering temperature is relatively low at 1150 to 1250 ° C.
In the case of sintering ferrite having a high magnetic permeability, the sintering temperature is relatively high at 1230 to 1400 ° C.

FIG. 5 is an explanatory view of an atmosphere firing furnace 100 used in this firing step. Atmosphere firing furnace 100
Only one has an opening serving as an entrance, and a shutter 101 is provided in the opening. Shutter 101
Is usually closed to maintain the atmosphere in the furnace,
The outside air is shut off. However, the shutter is not a completely airtight structure. By setting the atmosphere pressure in the furnace to a positive pressure with respect to the atmospheric pressure, the atmosphere gas in the furnace is allowed to flow out of the furnace little by little from the gap between the shutters. Has been. The platform 102 containing the ceramic raw material powder is introduced into the furnace with the shutter 101 opened. An atmosphere gas supply system 103 is connected to the atmosphere firing furnace 100, and the atmosphere gas is supplied via a pipe 104. As the atmosphere gas, for example, an inert gas such as a nitrogen gas or an argon gas is used. Then, in order to maintain the atmosphere in the firing furnace, an atmosphere gas is supplied from the atmosphere gas supply system 103 into the furnace at a constant flow rate, so that the inside of the furnace has a slightly higher positive pressure than the atmospheric pressure. .

[0005] The reason why the atmosphere in the firing furnace is set to an inert gas is that if an oxide layer is formed on the surface of the ceramics during the firing step, a predetermined magnetic property required for ferrite or the like can be obtained. Because there is no. The raw material powder that has been introduced into the furnace and has undergone the firing step at a predetermined temperature opens the shutter 101 again and is drawn out of the furnace.

In the above-described ceramic baking step, the above-mentioned polyvinyl alcohol added as an organic binder is thermally decomposed in an atmosphere baking furnace to generate low molecular aromatics and aldehydes. Most of these by-products are further thermally decomposed during the calcination process and converted to odorless carbon dioxide or water. However, low-molecular-weight odor substances such as acetaldehyde remain in a small amount without being thermally decomposed. The odor gas is gradually diffused outside the furnace from the gap even while the shutter is closed. Further, when the base plate 102 is taken in and out, the shutter 1
01 must be opened, and the odor gas remaining in the furnace flows out of the furnace. Therefore, it is necessary to deodorize these odor substances that have diffused and flowed out of the furnace. conventionally,
As a method of deodorizing such an odor gas, a method using a forced combustion device or a method using an adsorption deodorization device has been used. Hereinafter, these methods will be described with reference to the drawings.

FIG. 6 is a schematic overall configuration diagram of a conventionally used forced combustion device 110. Conventional forced combustion device 1
In 10, the odor gas generated from the odor generation source 111 is:
The gas is forcibly sucked and exhausted from the generation source 111 by the forced exhaust fan 112 and sent into the combustion furnace 113. A combustion gas supply system 114 is connected to a path between the forced exhaust fan 112 and the combustion furnace 113, and the odor gas is mixed with the combustion gas and introduced into the combustion furnace 113. Here, a combustible gas such as LNG or LPG is used as the combustion gas. When the combustion gas is introduced, a supporting gas such as air is also introduced at the same time as necessary. Combustion furnace 11
The odor gas introduced into 3 is burned together with the combustion gas and the supporting gas. The odor gas is burned and decomposed to produce carbon dioxide, water, and the like, and is exhausted outside the furnace. The deodorization method using such a forced combustion device has an advantage that the deodorization efficiency is high.

Next, FIG. 7 is a schematic overall configuration diagram of the adsorption / deodorization apparatus 120. Also in the adsorption / deodorization apparatus 120, the odor gas from the odor generation source 121 is forcibly sucked and exhausted from the generation source 121 by the forced exhaust fan 122, and is introduced into the adsorption / deodorization tower 123. Adsorption and deodorization tower 12
An adsorbent or a scrubber is arranged inside 3. For example, activated carbon is used as the adsorbent, and the odor gas is adsorbed on the surface of the activated carbon and removed. When a scrubber is used, the odorous gas is dissolved and removed in water while passing through the water shower of the scrubber. The exhaust gas from which the odorous gas has been removed and thus deodorized is exhausted from the adsorption deodorization tower 123.

[0009]

However, all of the above-mentioned conventional deodorizing methods have the following problems when used in the firing step of ceramics.

First, in the above-described method using the forced combustion device 110, the device is complicated and large. Therefore, it is inevitable that the initial cost and the running cost of the equipment are high and the occupied area increases. In addition, since the consumption of combustion gas is large and the inside of the combustion furnace 113 becomes hotter, it is usually necessary to coat the inside with a refractory brick, and maintenance and regular replacement of the refractory brick is also necessary. This also inevitably increases costs.

The flow rate of the odor gas flowing out of the above-mentioned atmosphere firing furnace is much smaller than the processing flow rate of a practical forced combustion apparatus. That is, in order to maintain the atmosphere in the atmosphere firing furnace, 100 l / H.
It is as follows. Obviously, the odor that actually escapes is even less. On the other hand, forcible combustion devices that have already been put into practical use are those having a flow rate of 10 m ³ / min or more. That is, the flow rate of the odor gas diffused and discharged from the atmosphere firing furnace is usually 1 / 1,000 or less of the actual exhaust flow rate of the forced exhaust fan 112. For this reason,
If a small amount of odor gas is forcibly exhausted from the above-described atmosphere firing furnace by such a large capacity forced exhaust fan 112, it is difficult to maintain the atmosphere in the firing furnace. That is, when this fan 112 is used, the inside of the furnace of the atmosphere firing furnace is forcibly exhausted, and the inside of the furnace has a negative pressure as compared with the surrounding pressure. Then, the atmosphere is mixed into the furnace, and as described with reference to FIG. 5, an oxide layer is formed on the surface of ceramics such as ferrite, and magnetic characteristics cannot be obtained.

Here, in order to maintain the atmosphere of the firing furnace, it is conceivable to restrict the exhaust flow rate of the forced exhaust fan 112. However, since it is necessary to balance the flow rate of the combustion gas supplied to the combustion furnace 113, the forced exhaust fan 1
Actually, it was extremely difficult to lower the exhaust gas flow rate of No. 12 in accordance with the flow rate of the odor gas. Further, if the shortage is compensated by flowing the atmosphere, most of the processing amount of the forced combustion device is used for the atmosphere for compensation, and waste is increased.

On the other hand, in the case of the adsorption / deodorization apparatus shown in FIG.
The odor gas is forcibly exhausted by the forced exhaust fan 122. Therefore, in the same manner as described above, it is necessary to significantly reduce the exhaust flow rate of the forced exhaust fan 122 in accordance with the amount of the odor gas diffused and discharged from the firing furnace 121. Further, activated carbon as an adsorbent has a problem that its adsorption efficiency for organic gas such as acetaldehyde is low. Furthermore, the used activated carbon that has absorbed these odor gases needs to be subjected to a special detoxification treatment in order to prevent secondary pollution. Therefore, such abatement disposal treatment also requires cost. When a scrubber is used for the adsorption, the water in the scrubber absorbs and dissolves the odor gas, and exhibits strong acidity. Therefore, a cost is required for the detoxification and disposal treatment in order to prevent the secondary pollution by the wastewater.

As described above, in the conventional deodorizer, it is not easy to maintain the atmosphere of the ceramics firing furnace.
There was a problem that the cost was high.

The present invention has been made in view of such a point. That is, an object of the present invention is to provide a deodorizing method and a deodorizing apparatus which can efficiently and inexpensively deodorize odor gas generated from a ceramic firing furnace with an extremely simple apparatus while maintaining the atmosphere in the firing furnace. Is what you do.

[0016]

That is, the method for deodorizing exhaust gas in an atmosphere firing furnace according to the present invention collects odor gas as exhaust gas emitted from the atmosphere firing furnace and directly burns the odor gas by a burner immediately after collection. The method has a configuration of an exhaust gas deodorizing method for an atmosphere firing furnace, in which the odor gas deodorized and burned by the burner is deodorized by passing through the gap of a metal carrier further heated.

The exhaust gas deodorizing apparatus for an atmosphere firing furnace according to the present invention includes a collection duct for collecting odor gas as exhaust gas from the atmosphere firing furnace, and a burner for directly burning and deodorizing the odor gas immediately after the collection. And a red-hot metal carrier that deodorizes by passing the odor gas burned and deodorized by the burner through a gap.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
While maintaining the atmosphere inside the ceramics firing furnace in an ideal state, the odor gas that diffuses and flows out of the furnace is efficiently collected by the collection duct, and the outside air as an oxygen supply source required for combustion is effectively used. It is introduced into a ring-shaped burner portion while mixing thoroughly, and is completely decomposed to deodorize.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of a main part of the present invention, and is a general configuration diagram of the main part in a state where a deodorizing apparatus according to the present invention is attached to an atmosphere firing furnace. FIG. 1A is a front view of a part thereof, and FIG. 1B is a side view thereof. As can be seen from the figure, the deodorizing device according to the present invention largely includes a collection duct 12 and an exhaust duct 16. The collection duct 12 is attached to the upper outside of the shutter 13 as an opening on one end side of the baking furnace 11, and while the shutter 13 is closed, the odor gas that diffuses and flows out of the gap and the shutter 13 is opened. The odor gas flowing out of the furnace when the raw material powder is taken in and out can be collected.

The exhaust duct 16 into which gas from the collection duct 12 flows has a combustion hood section 14 and an exhaust pipe section 19. The combustion hood portion 14 is configured as a substantially inverted cup-shaped member having a free opening below. Inside the combustion hood portion 14, a ring-shaped burner 15 is provided.
Is provided. That is, the upper end of the collection duct 12 enters through the opening of the combustion hood 14 and is located immediately below the ring-shaped burner 15. Further, a metal net-like metal carrier 17 is disposed above the ring-shaped burner 15 in order to completely burn or thermally decompose the odor gas from the collection duct 12. An exhaust pipe section 19 is connected to one side surface of the combustion hood section 14. A blower 18 that sucks and exhausts burned gas and the like is provided at the end of the exhaust tube portion 19.

FIGS. 2A and 2B show the combustion hood section 14.
It is the longitudinal section and the top view of ring-shaped burner 15 installed in the inside. The burner 15 has a plurality of craters 20, 20,... At regular intervals on the inner peripheral side surface of the ring-shaped burner main body 15A. Above the ring-shaped burner 15, a pilot burner 21 is provided.
Is provided. The pilot burner 21 has a crater 22 at its tip, and ignites the ring-shaped burner 15. When the ring-shaped burner 15 is ignited, FIG.
As shown in the figure, the flame 23 is emitted from the crater 20 toward the center of the ring. The tips of the flames 23 emitted from the respective craters 20 overlap each other on the center axis of the ring.

As the combustion gas supplied to the burner, for example, LPG can be mentioned. The amount of heat generated by the burner may be about 65,000 kcal / hour. Note that FIG.
In the above, a ring-shaped burner is shown, but the shape of the burner that can be used in carrying out the present invention is not limited to the ring-shaped one. That is, the shape of the burner may be any as long as the odor gas collected by the collection duct 12 is efficiently burned and decomposed. Therefore, examples of the shape of the burner include one in which one or more linear burners are combined in an arbitrary arrangement, and one in which ring-shaped burners having different diameters are arranged concentrically.

Next, the actual deodorizing action of the deodorizing device according to the present invention will be described. FIG. 3 is a partial cross-sectional view for explaining the operation of the deodorizing device according to the present invention. In the deodorizing device according to the present invention, first, the fuel gas is burned by the ring burner 15, and in this state, the blower 18 is driven to suck the gas in the collection duct 12 and the combustion hood portion 14 in the exhaust direction. Let it. At this time, the odor gas A that diffuses and flows out of the gap of the shutter 13 of the firing furnace 11 is sucked into the collection duct 12 together with the surrounding atmosphere B as shown in FIG. Will be introduced. At the same time, the surrounding air B is sucked into the combustion hood section 14 through the free opening below the combustion hood section 14. In burner 15,
The combustion gas such as LPG forms the flame 23,
The metal carrier 17 disposed above the burner is heated by the flame 23 and glows red. The odor gas A such as acetaldehyde introduced into the ring of the burner 15 is burned and decomposed by the flame 23, and is further burned and decomposed in contact with the high-temperature metal carrier 17 to obtain a treated gas such as carbon dioxide and water. Changes to The processed gas obtained as a result is exhausted in the direction of the arrow through the exhaust tube portion 19.

Here, in the deodorizing device according to the present invention, the collection duct 12 and the intake port of the combustion hood section 14 are opened so that the odor gas A is effectively collected together with the surrounding atmosphere B. ing. That is, since the pressure in the vicinity of the shutter 13 of the firing furnace 11 is not made unnecessarily negative as compared with the inside of the firing furnace 11, the gas in the furnace is not forcibly sucked. Atmosphere can be maintained. Therefore, unlike the conventional deodorizer, the inside of the furnace is forcibly sucked, and the atmosphere is not mixed and the atmosphere does not change.

Further, in the deodorizing apparatus according to the present invention, the upper end of the collecting duct 12 is formed to have a narrowed shape, and the opening thereof is disposed immediately below the ring-shaped burner 15. That is, since the odor gas A is collected and introduced into the center of the ring-shaped burner 15, the odor gas can be efficiently burned and decomposed with a compact thermal power. By doing so, the combustion gas required to burn and decompose the odor gas A is converted into a calorific value at about 65,0 / hour.
It is about 00 kcal, which can be reduced to one tenth or less of the conventional forced combustion device.

Further, in the deodorizing apparatus according to the present invention, the metal carrier 17 is disposed above the burner 15. That is,
Since the metal carrier 17 was arranged on the collection path of the odor gas A and was made to glow red by the flame 23 of the burner 15,
The combustion decomposition of the odor gas A can be promoted. Examples of such a material of the metal carrier 17 include metal materials such as stainless steel and high Ni-Cr heat resistant steel. Further, by using platinum or the like, an effect as a catalyst for a thermal decomposition reaction or a combustion decomposition reaction of an odor gas can be obtained. Further, the shape is desirably such that the contact area with the odor gas A is increased. In addition to a so-called wire mesh shape, a cotton shape, a blind shape, a honeycomb structure, a wound structure and the like can be mentioned.

Further, in the deodorizing apparatus according to the present invention, the blower 18 is disposed downstream of the burner 15. On the other hand, in a conventional forced combustion device as shown in FIG. 6 or an adsorption type deodorization device as shown in FIG. 7, odor gas such as acetaldehyde is directly sucked by a forced exhaust fan. Therefore, in these conventional devices, the forced exhaust fan is easily corroded by the odorous gas, causing a failure or the like. However, in the deodorizing device according to the present invention, since the blower 18 is disposed downstream of the burner 15, the blower 18 is not directly exposed to the odor gas A before being decomposed by combustion. Therefore, the blower 18 is not corroded, and a failure or the like can be prevented.

The inventor conducted an experiment for quantitatively examining the effect of the deodorizing apparatus according to the present invention. That is, FIG.
As shown in Table 2, a deodorizing device according to the present invention was attached to an atmosphere firing furnace, and a firing process of ceramics was performed. In the experiment, ferrite powder was used as the raw material powder. In addition, polyvinyl alcohol was used as a binder for the raw material powder. During the firing step, the burner 15 is turned on at 65,0 per hour.
The fuel was burned with a calorific value of 00 kcal, and the blower 18 was operated with a power of 7.5 W. The concentration of acetaldehyde as the odor gas was measured at two points near the outlet of the collection duct 12 and near the outlet of the exhaust duct 16. As a result, the measured concentration of acetaldehyde was about 30 ppm at the outlet of the collection duct 12, but was reduced to 1.2 ppm at the outlet of the exhaust pipe section 19. That is, it was found that acetaldehyde as an odor gas was sufficiently removed. The fired ferrite also showed good magnetic properties. That is, it was found that the atmosphere of the firing furnace was not affected by the deodorizing device. As described above, it was found that the deodorizing apparatus according to the present invention can efficiently perform the deodorizing treatment while sufficiently maintaining the atmosphere of the firing furnace.

FIG. 4 is a partial sectional view showing a modification of the deodorizing apparatus according to the present invention. In this example, the odor gas collection duct 42 is provided above the firing furnace 41. An exhaust duct 46 composed of a combustion hood 44 and an exhaust tube 49 is disposed above the collection duct 42, and is exhausted by a blower 48. A ring burner 45 is disposed inside the combustion hood 44, and a wire mesh-shaped metal carrier 47 is disposed above the ring burner 45. Firing furnace 4
The heated odor gas A generated in 1 rises in the collection duct 42, is sucked together with the atmosphere B by the blower 48, reaches the ring burner 45, and is decomposed by combustion. In addition, the metal carrier 4 disposed above the burner 45
7 further promotes the combustion decomposition reaction of the odor gas A. Then, carbon dioxide, water, and the like generated by the combustion decomposition reaction are exhausted by the blower 48. That is, according to the present modification, it becomes possible to effectively collect the odor gas A diffused and flowing out from above the firing furnace and perform the deodorizing treatment.

[0030]

The present invention is embodied in the form described above, and has the following effects. First, the deodorizer according to the present invention has a much simpler and more compact structure than conventional forced combustion devices and adsorption deodorizers. Therefore, the initial cost required for introducing the equipment is low.
Further, compared with the conventional forced combustion device, the consumption of the combustion gas is one-tenth or less, and the running cost is low.
Further, the burner is exposed, so that maintenance of firebricks or the like is not required. Furthermore, it can be easily attached to a general-purpose atmosphere firing furnace without any modification.

Further, the deodorizing apparatus according to the present invention can perform an odor gas deodorizing treatment while maintaining the atmosphere in the atmosphere firing furnace. That is, since the pressure around the shutter of the firing furnace is not unnecessarily reduced to a negative pressure, the atmosphere in the furnace can be maintained without forcibly sucking the atmosphere in the furnace. Therefore, unlike the conventional deodorizing apparatus, the inside of the furnace is not forcibly sucked, the atmosphere is mixed, and the quality of the ceramics to be fired is not deteriorated.

Further, in the deodorizing device according to the present invention, since the blower is disposed downstream of the burner, the blower is not directly exposed to the odor gas before combustion and decomposition. Therefore,
The blower 18 is not corroded, and the failure of the blower can be prevented.

As described above, according to the present invention, the deodorizing treatment of the odor gas generated from the ceramics atmosphere baking furnace, which has been difficult in the past, is performed with an extremely simple apparatus while maintaining the atmosphere in the baking furnace. Can be performed easily and accurately. INDUSTRIAL APPLICABILITY As described above, the present invention has an extremely remarkable industrial effect, and its value is extremely large.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram illustrating an entire configuration of a main part of the present invention, in which a deodorizing apparatus according to the present invention is attached to an atmosphere firing furnace.

FIGS. 2A and 2B are a longitudinal sectional view and a plan view of a ring-shaped burner 15 installed in a combustion hood section 14. FIGS.

FIG. 3 is a partial cross-sectional view for explaining the operation of the deodorizing apparatus according to the present invention.

FIG. 4 is a partial sectional view showing a modification of the deodorizing device according to the present invention.

FIG. 5 is an explanatory view of an atmosphere firing furnace 100 used in a ceramics firing step.

FIG. 6 is a schematic overall configuration diagram of a conventionally used forced combustion device 110.

FIG. 7 is a schematic overall configuration diagram of an adsorption / deodorization apparatus 120.

[Explanation of symbols]

 11, 41 Furnace body of firing furnace 12, 42 Collection duct 13 Shutter 14, 44 Combustion hood 15, 45 Ring burner 16, 46 Exhaust duct 17, 47 Metal carrier 18, 48 Blower 19, 49 Exhaust cylinder 20, 22 Tinder 21 Pilot burner 23 Flame 100 Atmosphere firing furnace 101 Shutter 102 Raw material powder bed 103 Atmospheric gas supply system 110 Forced combustion device 111 Odor generation source 112 Forced exhaust fan 113 Combustion furnace 114 Combustion gas supply system 120 Adsorption and deodorization device 121 Odor Source 122 Forced exhaust fan 123 Adsorption and deodorization tower

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01D 53/74 B01D 53/34 ZAB C04B 35/64 116H F23J 15/08 C04B 35/64 A F23L 17/16 609 F23J 15/00 L F27B 17/00

Claims (4)

[Claims] 1. A metal which collects odor gas as exhaust gas emitted from an atmosphere firing furnace, directly burns and deodorizes the odor gas by a burner immediately after collection, and further heats the odor gas burned and deodorized by the burner. A method for deodorizing exhaust gas in an atmosphere firing furnace, which deodorizes by passing through a gap between carriers. The burner and the metal carrier are housed at the end of the duct to carry out each of the above-mentioned treatments, and the blower provided at the end of the duct converts the odor gas into the odor gas at the end of the duct. 2. The deodorizing method according to claim 1, wherein oxygen is supplied by mixing. 3. A collection duct for collecting odor gas as exhaust gas from an atmosphere firing furnace, a burner for directly burning and deodorizing the odor gas immediately after collection, and a gap for burning and deodorizing the odor gas by the burner. And a red-heated metal carrier that deodorizes by passing through it. 4. A duct for sucking and exhausting the odor gas, wherein the burner and the metal carrier are provided at a distal end of the duct, and an air is supplied to the odor gas at a distal end of the duct at a terminal end of the duct. 4. The deodorizing apparatus according to claim 3, further comprising a blower mixed to supply oxygen.