JP2005331162A - Continuous furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous furnace of low initial introduction cost and operation cost, capable of using a compact combustion type deodorizing device in comparison with a conventional one. <P>SOLUTION: The smoke generated from a burned substance in a furnace body 12 is sucked into a smoke suction pipe 70 from an opening 76 formed near the burned substance by an air blower 72, and burned at a temperature of about 800°C by a deodorizing device 74 to be deodorized. As the opening 76 of the smoke suction pipe 70 is formed near the burned substance, the smoke generated from the burned substance is efficiently sucked from the opening 76, and prevented from mixed with the gas of high temperatures flowing from a burning zone 34. Thus the quantity of gas burned by the deodorizing device 74 is remarkably reduced in comparison with a case when the exhaust gas of the mixture of the smoke and the gas of high temperatures is fully sent to the deodorizing device 74. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a continuous firing furnace, and more particularly to a continuous firing furnace equipped with a deodorizing apparatus.

  A high-temperature part having a heat source and a low-temperature part having an exhaust device are provided with a tunnel-like furnace body provided separately in the conveying direction, and the exhaust device can control the flow rate of the high-temperature gas flowing from the high-temperature part toward the low-temperature part. There is known a continuous firing furnace in which a fired product containing a large amount of organic components is fired in the process of being conveyed through the furnace while adjusting the temperature of the low temperature part. For example, a gas burner is provided as a heat source, and the combustion gas is flowed to the inlet side to form a heat curve for the entire furnace, and the firing is performed by a number of rollers that are rotated around the axis perpendicular to the direction of conveyance of the fired product. One example is a roller hearth kiln that supports and conveys an object (see, for example, Patent Document 1).

  In such a continuous firing furnace, in the process of raising the temperature in the low temperature part, organic components such as a molding binder contained in the fired product are evaporated and burned to be removed (ie, degreased). At this time, in the initial stage of the degreasing process, although the organic component is removed, the temperature is not high enough to burn it, so that a product gas accompanied by odor is generated. Since this produced gas is mixed with the combustion gas and goes to the exhaust passage, it is not described in Patent Document 1, but in the continuous firing furnace as described above, the exhaust gas mixed with these produced gas and the combustion gas is used. For example, a combustion type deodorizing device is provided in the exhaust passage for combustion (combustion type), or an air introduction port is provided in the exhaust passage and diluted with odorless air (diffusion type).

In addition, although the type of the baking furnace is different, there have been many patent applications related to exhaust gas deodorization. For example, an exhaust pipe is provided in the heating area of the tunnel-shaped furnace body (i.e., the high temperature part), and an air supply pipe is provided in the processing object moving path outside it, and these are circulation type having a heat exchanger and an adsorber. By connecting to the gas purification device, the gas in the heating zone of the furnace body is led from the exhaust pipe to the adsorber via the heat exchanger, and is collected by forced cooling in the adsorber ( For example, see Patent Document 2). Further, an exhaust passage is disposed in the vicinity of a firing zone (that is, a high-temperature portion) or a temperature-raising zone (that is, a low-temperature portion), and the exhaust gas is reburned by the heat to deodorize (for example, Patent Document 3). reference). Also known are those that collect exhaust gas in the middle of the exhaust system and burn it using a gas burner, and those that collect exhaust gas in a combustion chamber provided under the floor of the furnace body to burn and deodorize ( For example, see Patent Documents 4 and 5). Since these are firing furnaces of the type heated by an electric heater, the exhaust gas is a gas generated by degreasing or a mixed gas of this and an ambient gas.
Japanese Patent Laid-Open No. 11-043380 Japanese Utility Model Publication No. 55-103497 JP 2002-168571 A Japanese Utility Model Publication No. 1-123196 Japanese Patent No. 2522878

  By the way, in the case of producing porous ceramic products such as fillers, catalyst carriers, and grindstones, a large amount of pore forming material is added for the purpose of forming a large number of pores and making them porous. In addition, a large amount of an organic binder is added for the purpose of improving the shape retention of the molded body. Therefore, in the initial stage of the degreasing process of the firing treatment, a large amount of odorous gas is generated from these large amounts of organic components. However, in order to deodorize a large amount of product gas in the continuous firing furnace, it is necessary to provide a large output fan and introduce a remarkably large amount of air into the exhaust passage in the diffusion type. In the combustion type, the exhaust gas whose temperature is lowered in the exhaust passage by air introduced for the purpose of adjusting the temperature in the furnace and protecting the fan is about 800 (° C.) in the combustion type deodorization device. It is necessary to heat to a high temperature.

  Therefore, in any case, since a large output fan and a large combustion deodorizing device are provided, the initial introduction cost becomes high. In particular, in the combustion type, for example, a large amount of fuel equivalent to that used for firing is consumed. There was a problem that was necessary. In addition, in the firing furnace equipped with the gas burner as a heat source, the combustion gas is also included in the exhaust gas, so the amount of exhaust gas is larger than in a firing furnace heated by an electric heater, The problems of initial introduction cost and operation cost are more serious.

  The present invention has been made against the background of the above circumstances, and the purpose of the present invention is to provide a continuous firing furnace that can be used for a small-sized combustion deodorizer compared to the prior art and has low initial introduction costs and operation costs. It is to provide.

  In order to achieve such an object, the gist of the present invention includes a tunnel-shaped furnace body in which a high-temperature part having a heat source and a low-temperature part having an exhaust device are provided separately in the transport direction, and from the high-temperature part While controlling the temperature of the low-temperature part by adjusting the flow rate of the hot gas flowing toward the low-temperature part by controlling the temperature of the low-temperature part, the fired product containing a large amount of organic components is baked in the process of transporting through the furnace body A continuous firing furnace of a type that deodorizes and discharges a product gas accompanied by an odor generated from the fired product in the furnace body, wherein (a) one end is located in the furnace body and the other end is outside the furnace body And a generated gas suction pipe provided with a plurality of openings at a position in the vicinity of the fired product in the generated gas generation region in one end side thereof, and (b) the generation from the plurality of openings. Sucking gas and sucking the generated gas A blower for flowing toward the other end of the suction pipe, and (c) provided on the other end side for deodorizing by burning the generated gas led to the other end side of the generated gas suction pipe at a predetermined temperature. And a deodorizing device.

  In this way, the generated gas generated from the fired product in the furnace body is sucked into the product gas suction pipe from the opening provided near the fired product by the blower, and the other end located outside the furnace body. Deodorized by being led to the side and burned at a predetermined temperature by a deodorizing device. Therefore, since the opening of the product gas suction pipe is provided in the vicinity of the fired product, the product gas accompanied by the odor generated from the fired product is efficiently sucked from the opening, so that the high temperature flowing from the high temperature part Mixing with gas is suppressed. That is, the product gas is exclusively sucked into the product gas suction pipe, and the high temperature gas is exhausted by the exhaust device as in the conventional case. Therefore, the amount of gas burned by the deodorizing device is remarkably reduced as compared with the case where the entire amount of the exhaust gas mixed with the product gas and the high temperature gas is sent to the deodorizing device. As described above, since a small-sized deodorizing device is sufficient as compared with the conventional one, the initial introduction cost is low, and the amount of processing gas is reduced, so that a continuous firing furnace with low operating cost can be obtained.

In addition, as a result of the above, the amount of combustion gas in the deodorizing apparatus is reduced, so that the amount of CO ₂ generated is reduced. Moreover, since the operating conditions of the deodorizing device and the blower and the pipe diameter of the generated gas suction pipe can be changed according to the amount of generated gas, there is an advantage that the operating cost can be reduced according to the amount of generated gas. On the other hand, in the conventional firing furnace in which the entire exhaust gas is processed by the deodorizer, it is necessary to process a large amount of high-temperature gas (for example, combustion gas) regardless of the amount of generated gas, so that the generated gas is small. In some cases, it was necessary to operate the deodorizing apparatus under substantially constant conditions corresponding to the case where the amount of generated gas was large.

  The “position close to the calcined product” is a position near the position where the calcined product determined according to the structure of the calcining furnace is to be disposed, but the calcined product having various sizes of calcined products is a processing target. May be changeable according to the size.

  In addition, since the suction efficiency of the generated gas (that is, the gas collection efficiency) decreases as the opening moves away from the fired product, the opening is preferably provided as close to the fired product as possible.

  Incidentally, in any of the firing furnaces described in Patent Documents 2 to 5, since all exhaust gas discharged from the furnace body is collected in a common exhaust passage, a large processing capacity is required for the deodorizing apparatus. . All of these firing furnaces are of the type heated by an electric heater, but regardless of whether they are heated by an electric heater or heated by a burner, if the generated gas from the fired product is not selectively sucked, Large equipment and a large amount of fuel are required to heat a large amount of gas discharged from the furnace.

  Here, preferably, the furnace body supports and conveys the fired product by a number of rollers that are rotated around an axis perpendicular to the transport direction of the fired product. A suction port that opens to a space provided on the side is provided connected to the exhaust device. In other words, the present invention is preferably applied to a so-called roller hearth kiln. In this way, the high-temperature gas sent from the high-temperature section is sucked from the suction port, and then flows into the space below it through the gaps between the many rollers, and further sent to the exhaust device. It is done. Therefore, since an air flow from the high temperature part toward the low temperature part and further toward the lower side of the roller at the low temperature part can be formed in the furnace body, the generated gas generated from the fired product is also directed downward from the fired product on this air stream. . Therefore, by determining the position of the opening in accordance with the flow of the product gas, the product gas can be sucked with higher efficiency. That is, the amount of generated gas that is not sucked into the generated gas suction pipe and goes to the exhaust device is reduced.

  Preferably, the product gas suction pipe is inserted from the low temperature side opening of the furnace body located on the inlet side of the fired product toward the high temperature side. In this way, the product gas with odor is generated in the low temperature part where the fired product is degreased, so the product gas suction pipe inserted from the low temperature side opening is, for example, about 500 (° C) or less in the furnace body. It is sufficient to place it only in the relatively low temperature region. Therefore, since high heat resistance is not required, there is an advantage that the generated gas suction pipe can be configured with a material that is easy to handle such as stainless steel. Moreover, since this can be provided only by inserting the product gas suction pipe from the opening on the low temperature side of the furnace body, there is also an advantage that almost no change in the structure of the firing furnace is required. In the present invention, it is sufficient that an opening is provided in the vicinity of the fired product, and the opening and the other end outside the furnace body may be connected by any route. For example, the product gas suction pipe can be provided through the side wall or the bottom wall of the furnace body. However, if it is inserted from the entrance side of the fired product as described above, it is not necessary to make any changes to the furnace body.

  Preferably, the plurality of openings have an opening diameter that decreases from the low temperature side toward the high temperature side. In this way, since the amount of gas generated when the calcined product is degreased is high on the low temperature side and low on the high temperature side, it is possible to suppress the use of deodorizing unnecessary gas to the deodorizing device. The apparatus can be further reduced in size.

  Preferably, a guide plate for guiding the generated gas to the plurality of openings is provided along a longitudinal direction of the generated gas suction pipe. In this way, the flow of the product gas that flows to the exhaust device through the periphery of the product gas suction pipe is blocked by the guide plate, so that the product gas can be sucked into the product gas suction pipe more efficiently. The guide plates are preferably provided on both sides of the opening in the circumferential direction of the product gas suction pipe.

  Moreover, although the said many opening is a through-hole which penetrates the surrounding wall of the said production | generation gas suction piping, the shape and magnitude | size are suitably changed according to a baked product. For example, an elongated gap (that is, a slit) may be provided instead of the through hole, and a net (for example, a wire net) may be provided at the position where the through hole is formed.

  Further, the size of the opening is made as small as possible within a range in which substantially the entire amount of the generated gas can be sucked. If it does in this way, since it sucks in the useless gas of a deodorizing process, a deodorizing device can be further miniaturized.

  Preferably, the fired product is fired in a predetermined position, for example, in a state where the fired product is housed in a predetermined firing container having a long and narrow gap (that is, a slit) on a side surface. An air flow in the furnace body is formed so that the generated gas is discharged from the gap. In this way, since the distribution path of the product gas is further limited, it can be sucked more efficiently. For example, as described above, in the roller hearth kiln, the air flow can be formed by providing a suction port connected to an exhaust device on the lower side of the roller.

  Preferably, the high temperature part includes a gas burner as a heat source, and adjusts the temperature of the low temperature part by flowing the combustion gas toward the low temperature part. The present invention is suitably applied to a continuous firing furnace of the type heated by such a gas burner.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a diagram showing an entire roller hearth kiln 10 as an example of a continuous firing furnace of the present invention. The roller hearth kiln 10 is a kind of tunnel furnace that performs heat treatment while transporting the fired product along one direction. The roller hearth kiln 10 has a total length of about 20 (m), for example, and has a tunnel 12 and a large number in the tunnel 12. And a roller 14 (see also FIG. 3 and the like) for conveying the fired product provided.

  As shown in a cross section at an arbitrary position in FIG. 2, the roller 14 is provided horizontally through the tunnel-shaped furnace body 12, and a pedestal 16 and a bearing 18 provided on the side of the furnace body 12. Is rotatably supported by. A large number of rollers 14 are arranged on a horizontal plane and are rotated around the respective axis centers at the same rotational speed, whereby the sheath 19 in which the fired product is accommodated is heated at a constant speed. It is conveyed inside. The furnace body 12 is composed of a casing 20 made of a steel plate and a heat insulating wall 22 made of a refractory material, and is supported on a base 26 by leg portions 24 provided at both ends in the cross section.

  Returning to FIG. 1, the roller hearth kiln 10 includes a first pre-tropical zone 30 and a second pre-tropical zone (temperature rising zone) 32 provided in order from the fired product inlet 28 side located at the left end in FIG. , A firing zone (keep zone) 34, and a cooling zone 36. The first tropical zone 30 includes a plurality of temperature controllers 38, an exhaust device 40, and a deodorizing device unit 42. Further, the second pre-tropical zone 32 is provided with a plurality of temperature controllers 44 and a cooling device 46. The firing zone 34 includes a plurality of temperature controllers 48 and a plurality of burners 50. The cooling zone 36 is provided with a plurality of temperature regulators 52, a cooling device 54, and an exhaust device 56.

  The exhaust device 40 provided in the first pre-tropical zone 30 includes two exhaust cylinders 58 connected to substantially the center in the width direction of the ceiling portion of the furnace body 12 and four exhaust cylinders connected to the lower portions of both side surfaces. An exhaust cylinder 60, an exhaust cylinder 62 provided at the fired product inlet 28, and a common exhaust passage 64 to which they are connected are provided. Note that only the exhaust pipe 60 located on the near side is shown in FIG. These exhaust cylinders 58, 60, 62 and the exhaust passage 64 are respectively provided with rotary or plug-in type dampers 66.

  As schematically shown in the cross-sectional structure of the first pre-tropical zone 30 in FIG. 3, the exhaust pipe 58 passes through the ceiling portion of the furnace body 12 and opens to the ceiling surface inside the furnace body. Further, the exhaust tube 60 is bent at a substantially right angle so that the lower end portion is directed toward the furnace body 12, and the tip thereof is opened at the bottom surface inside the furnace body or a position slightly above it. In FIG. 3, it is drawn so as to open toward the bottom of the furnace body for the convenience of illustration. Moreover, the lower end surface of the exhaust pipe 62 is opened. Further, the exhaust passage 64 has a cylindrical shape with both ends open, and is provided with the damper 66 at the right end on the side of the firing zone 34 located on the right side in FIG. An exhaust fan 68 is provided.

  Further, the deodorizing device unit 42 includes two smoke suction pipes 70 which are inserted into the furnace body 12 on the right end side in FIG. 3 and placed on the roller 14, and an exhaust fan provided on the left end side thereof. 72 and a combustion-type deodorizing device 74. The smoke suction pipe 70 has a bellows-like peripheral wall made of, for example, stainless steel, and has an outer diameter of, for example, about 25 (mm). One end located in the furnace body 12 is positioned slightly closer to the firing zone 34 than the position where the exhaust pipes 58 and 60 are disposed, and is within a range of, for example, about 2.5 (m) from the fired product inlet 28. Has been placed. Further, the smoke suction pipe 70 has a constant value of about 5 (cm), for example, in the range from the tip on the side of the firing zone 34 to the vicinity of the fired product inlet 28, for example, about 80 (cm) from the firing zone 34. A large number of openings 76 are provided in a row toward the sheath 19 at a central interval of.

  FIG. 4 is an enlarged view of one side of the smoke suction pipe 70 described above. The size of the opening 76 provided in the smoke suction pipe 70 is changed stepwise, for example, in two steps from the blower 72 side, that is, the base end side, toward the firing zone 34 side, that is, the front end side (not shown). The diameter of the opening 76 is, for example, about 10 (mm) at the base end side, about 6.5 (mm) at the intermediate portion, and about 5.5 (mm) at the distal end side. The smoke suction pipe 70 has a pair of long thin plate-like guides 78 and 78 (that is, guide plates) extending along the axial direction of the smoke suction pipe 70 in the circumferential direction on both sides of the opening 76. It is fixed throughout. Similarly to the smoke suction pipe 70, the guide 78 is made of stainless steel or the like, and has a height, that is, a length in a direction away from the smoke suction pipe 70, as shown in FIG. The dimension is about 13 (mm), for example, and protrudes substantially in the radial direction.

  Further, as shown in FIG. 2, the other of the pair of smoke suction pipes 70 is provided symmetrically with the one. In other words, the openings 76 and 76 and the guides 78 and 78 are arranged to face each other. Further, as shown in FIG. 5, the smoke suction pipe 70 is positioned at a position where the guide 78 is in contact with the sheath 19 or slightly separated.

The deodorizing device 74 is, for example, a device that burns the supplied gas by heating it to a temperature of about 800 (° C.), decomposes organic components, and deodorizes, for example, 10 (m ³ / min).

  The cooling device 46 controls the inside of the furnace body 12 to a necessary temperature by, for example, driving cool air from above and below the roller 14 and the sheath 19.

  In addition, the burner 50 provided in the firing zone 34 generates high-temperature gas by burning, for example, liquid fuel or gas fuel. In this embodiment, the burner 50 functions as a heat source for the roller hearth kiln 10, and the pretropics 30 and 32 are not provided with any heat source. Therefore, the temperature control of these pre-tropics 30 and 32 is performed by operating the plurality of dampers 66 of the exhaust device 40 to discharge the high-temperature gas from the exhaust cylinders 58, 60 and 62 and to the exhaust passage 64. This is done by changing the air intake amount. The plurality of arrows in FIG. 3 represent the flow state of these hot gases, the air intake path, and the like. Thereby, a temperature gradient as shown in FIG. 7 described later is formed in the pre-tropics 30 and 32.

  Further, the exhaust device 56 provided in the cooling zone 36 includes two exhaust cylinders 80 connected to the approximate center in the width direction of the ceiling portion of the furnace body 12 and two exhaust cylinders connected to the lower portions of both side surfaces. An exhaust cylinder 82, an exhaust cylinder 86 provided at the fired product outlet 84, and a common exhaust passage 88 to which they are connected are provided. The exhaust device 56 is configured in the same manner as the exhaust device 40 except that the number of exhaust cylinders 82 connected to the lower portion of the furnace body 12 is different, and is similarly provided with a damper 90. . The cooling device 54 is configured in the same manner as the cooling device 46.

  Further, as shown in FIG. 5, the fired product 92 is stored in a sheath (that is, a firing container) 19, and the sheath 19 has a gap 94 formed in the lower portion. The opening 76 of the smoke suction pipe 70 is provided at a position near the gap 94 toward the gap 94. For example, as shown in FIG. 6, the sheath 19 is obtained by placing a frame 98 on a thin plate-like flat setter 96. Each of the setter 96 and the frame 98 is made of a refractory material such as alumina or silica. The frame 98 has a rectangular frame shape, and two recesses 100 are provided on each side of the lower end surface on the setter 96 side. The gap 94 is formed by the recess 100 when the frame 98 is placed on the setter 96. Note that the fired product 92 is, for example, a Raschig ring-shaped molded body as shown in FIG. 5 and is housed in the sheath 19 in a large amount. This molded body is produced, for example, by extruding an alumina raw material and cutting it at an appropriate size.

  In the roller hearth kiln 10 configured as described above, by rotating the roller 14, the sheath 19 containing the fired product 92 is sequentially fed from the fired product inlet 28, and the inside of the furnace body 12 is transferred. The fired product 92 is fired by sending it out from the fired product outlet 84. At this time, the fuel is burned by the burner 50 of the calcining zone 34 to generate high-temperature gas (that is, combustion gas), and the exhaust devices 40 and 56 are controlled to adjust the flow rate of the generated high-temperature gas so The temperatures of the tropics 30 and 32 are controlled, and for example, a predetermined temperature gradient as shown by a one-dot chain line in FIG. 7 is formed in the furnace body 12. For this reason, the fired product 92 is gradually heated during transfer, then fired at a constant temperature, and gradually cooled.

  FIG. 7 shows temperature change data at the time of degreasing, that is, 0 to 120 minutes, collected by actual operation, with the horizontal axis representing the time after furnace entry and the vertical axis representing temperature. In this figure, the alternate long and short dash line indicates the set temperature (temperature profile programmed in the control device), ○ and the broken line indicate the temperature at the top of the sheath 19 (that is, the top of the fired product), and ◆ and the solid line indicate the temperature inside the sheath 19, that is, the firing. This represents the temperature of the object 92. In the present embodiment, for example, firing is performed in about 360 minutes, but the temperature profile after the second half of the second pretropical zone 32 (not shown) is arbitrarily set according to the fired product. As described above, since the overall length of the roller hearth kiln 10 is about 20 (m), the transfer speed of the fired product 92 is set so as to move 20 (m) in about 6 hours.

  By the way, in this embodiment, the fired product 92 is, for example, a Raschig ring-shaped molded body, and this molded body contains a large amount of organic components added for the purpose of obtaining porous ceramics used for, for example, a carrier. . The type and content of the organic component is appropriately determined according to the type of the fired product 92. For example, the total amount of the organic binder and the pore forming material is 5 (wt%) or more, for example, 8 to 14 (wt %) Content. Therefore, the amount of the fired product 92 accommodated in the sheath 19 is, for example, about 5 to 6 (kg) in terms of the mass of the molded body, but in the firing process, for example, about 0.4 to 0.7 (kg) per sheath 19. Some organic components will be burned off. Table 1 below shows an example of the amount of organic components.

[Table 1]
Variety A B C
Mass after firing per sheath (kg) 4.7 5.2 5.7
Formulation Organic binder 7.8 7.8 6.4
(%) Pore forming material 6.2 6.2 1.6
Total 14.0 14.0 8.0
Binder amount per sheath
(kg) Organic binder 0.37 0.41 0.37
Pore forming material 0.29 0.32 0.09
Total 0.66 0.73 0.45

  In the process of burning out the organic component, first, smoke in an incompletely burned state is generated, and then, when the temperature is sufficiently high, a phenomenon in which the organic component is decomposed and smoke is not emitted is observed. This incompletely combusted smoke is accompanied by, for example, an odor with an odor concentration of about 10,000 to 50,000, and it is stipulated in the Odor Prevention Law and the like to discharge after deodorizing. For example, in the vicinity of residential land, the odor concentration must be reduced to 300 or less. Conventionally, deodorization is performed by reducing the odor by using fresh air taken in from the combustion gas or the damper 66 or by providing a combustion type deodorizing device 102 in the exhaust passage 64 (see FIG. 3).

  In addition, the said odor density | concentration is calculated by the "method of calculating an odor index and odor discharge intensity" defined based on the bad odor prevention law enforcement regulations. According to this calculation method, odorless air is injected into the odor bag, and a sample (gas with odor) is injected to achieve a predetermined dilution ratio. The dilution rate at which the presence / absence is determined and a predetermined accuracy rate cannot be obtained is determined as the odor concentration.

  In the present embodiment, when the smoke accompanied by the odor is generated from the fired product 92, the smoke is directed to the exhaust tube 60 opened at the lower portion of the side wall along the flow of the hot gas in the furnace body 12. That is, in FIG. 5 described above, the generated smoke does not travel upward of the sheath 19 but travels downward through the gap 94. However, since the smoke suction pipe 70 having a large number of openings 76 is disposed in the vicinity of the gap 94, the smoke is caused to flow into the smoke suction pipe 70 as indicated by the arrow g by the suction force of the blower 72. Sucked into. The guide 78 plays a role of guiding and collecting the smoke toward the opening 76 when sucking the smoke.

  As a result, the smoke generated from the fired product 92 is hardly mixed with the high-temperature gas flowing into the exhaust pipes 58 and 60 as shown in FIG. 3, so that the odor concentration in the exhaust passage 64 is extremely low, for example, 300 Only about ~ 500. On the other hand, since the high temperature gas is hardly sucked into the smoke suction pipe 70 and only smoke is sucked in, the amount of sucked gas is relatively small. That is, the suction force by the blower 72 is determined as such. The sucked smoke is sent into a combustion type deodorizing device 74 provided at the rear of the blower 72, and is heated to, for example, 800 (° C.) to be burned, decomposed, and deodorized. That is, the odor concentration is reduced to 300 or less.

  As described above, the smoke suction pipe 70 is inserted from the inlet 28 of the furnace body 12 to a position of about 2.5 (m), and the opening 76 does not exist on the firing zone 34 side. Further, the opening 76 is not provided in a range up to about 80 (cm) in the vicinity of the inlet 28. Therefore, the smoke is sucked only in the range of 0.80 to 2.5 (m) and its vicinity when the position of the inlet 28 is 0 (m). The reason for this setting will be described below.

  FIG. 8 shows, for example, the results of thermogravimetry (TG) of the baked product 92 of cultivar A in Table 1 above. In FIG. 8, up to about 100 (° C.) is mostly a reduction due to evaporation of moisture, and after that (higher than that) is a reduction due to evaporation or decomposition of organic components. The weight loss becomes abrupt when it exceeds 200 (° C.) and is almost finished at about 500 (° C.) (range indicated by an arrow). In this range, the organic component is evaporated and decomposed to generate a gas, which is considered to be in a smoke state or a combustion state depending on the furnace atmosphere temperature. For example, the gas generated in the low temperature range of about 200 to 700 (° C.) of the roller hearth kiln 10 is considered to be in a smoke state.

  When this temperature range is seen in FIG. 7 above, decomposition gas begins to be generated at a position of about 80 (cm) from the inlet 28 at the upper portion of the sheath 19 (that is, the uppermost portion of the fired product), and a position of about 2.5 to 3 (m). Combustion starts at over 700 ° C. Moreover, since the temperature rise of the fired product 92 inside the sheath 19 is delayed from the upper portion of the sheath 19, cracked gas begins to be generated at a position of about 2.5 (m) from the inlet 28, but since the furnace temperature is already high, The generated gas is burned. There is no need for smoke suction since no smoke is generated after the start of combustion. Therefore, the opening 76 is provided in the range of 0.8 to 2.5 (m) according to the range in which smoke is generated. Further, as apparent from these, the amount of smoke generated decreases toward the firing zone 34 side, so that the suction force can be decreased toward the tip side of the smoke suction pipe 70. Therefore, as described above, the size of the opening 76 is made smaller toward the tip side.

As described above, according to the present embodiment, the smoke generated from the fired product 92 in the furnace body 12 is sucked into the smoke suction pipe 70 from the opening 76 provided near the fired product 92 by the blower 72. Further, it is guided to the other end located outside the furnace body 12 and is deodorized by being burned by the deodorizing device 74 at a temperature of about 800 (° C.). Therefore, since the opening 76 of the smoke suction pipe 70 is provided in the vicinity of the fired product 92, the smoke generated from the fired product 92 is efficiently sucked from the opening 76 and flows from the fired zone 34. Mixing with high temperature gas (combustion gas) is suppressed. That is, smoke is exclusively sucked into the smoke suction pipe 70, and the high temperature gas is exhausted by the exhaust device 40 exclusively as in the conventional case. Therefore, compared with the case where the entire amount of exhaust gas in which smoke and high-temperature gas are mixed is sent to the deodorizing device 74, the amount of gas burned by the deodorizing device 74 is significantly reduced. For example, when the combustion type deodorizing device 102 is provided in the exhaust passage 64 as shown by the one-dot chain line in FIG. 3, a processing capacity of about 50 (m ³ / min) is required. Therefore, about 1/5 of the processing capability is sufficient.

  Further, according to the present embodiment, the high-temperature gas sent from the firing zone 34 is sucked from the suction port of the exhaust pipe 60, thereby passing through the gaps between the many rollers 14 and the space below it. Then, it flows into the exhaust device 40. Therefore, an air flow from the firing zone 34 toward the first pre-tropical zone 30 and further toward the lower side of the roller 14 in the first pre-tropical zone 30 can be formed in the furnace body 12, so that smoke generated from the fired product 92 is also converted into this air flow. It rides and is directed downward from the fired product 92. Therefore, by determining the position of the opening 76 in the vicinity of the gap 94 where the smoke is discharged, the smoke can be sucked with higher efficiency. That is, the amount of smoke directed to the exhaust device 40 without being sucked into the smoke suction pipe 70 is reduced.

  Further, according to the present embodiment, the smoke suction pipe 70 is inserted from the fired product inlet 28, but the temperature at the tip position is kept at about 600 (° C.) at most as is apparent from FIG. Therefore, since high heat resistance is not required, the smoke suction pipe 70 can be configured with a material that is easy to handle, such as stainless steel, as described above. In addition, since the smoke suction pipe 70 can be provided simply by inserting it from the inlet 28 of the furnace body 12, it is unnecessary to change the structure of the roller hearth kiln 10.

  As mentioned above, although this invention was demonstrated in detail with reference to drawings, this invention can be implemented also in another aspect, A various change can be added in the range which does not deviate from the main point.

It is a figure which shows the whole structure of an example of the continuous-type baking furnace of one Example of this invention. It is a figure which shows the cross section of the continuous firing furnace of FIG. It is a figure explaining the structure of the exhaust apparatus 40 and the deodorizing apparatus 74 with which the 1st pretropical zone of the continuous-type baking furnace of FIG. 1 was equipped. It is a figure explaining the smoke suction piping 70 which comprises the deodorizing apparatus 74 of FIG. It is a figure explaining the cross-section of smoke suction piping. It is a figure explaining the baking device in which the baked product 92 processed with the baking furnace of FIG. 1 is stored. It is a figure explaining the relationship between the elapsed time after throwing in the continuous-type baking furnace of FIG. 1, and temperature. It is an example of the result of the thermogravimetry (TG) of the baked product 92.

Explanation of symbols

10: Roller Hearth Kiln, 12: Furnace, 14: Roller, 28: Baked product inlet, 30: First pre-tropical zone (low temperature part), 34: Firing zone (high temperature part), 40: Exhaust device, 42: Deodorizing device Unit: 70: Smoke suction pipe, 72: Blower, 74: Combustion deodorizer, 76: Opening, 78: Guide

Claims (5)

A high-temperature part having a heat source and a low-temperature part having an exhaust device are provided with a tunnel-like furnace body provided separately in the conveying direction, and the exhaust device can control the flow rate of the hot gas flowing from the high-temperature part toward the low-temperature part. While adjusting and controlling the temperature of the low temperature part, the fired product containing a large amount of organic components is fired in the process of transporting through the furnace body, and the product gas accompanied by odor generated from the fired product in the furnace body is produced. It is a continuous firing furnace that deodorizes and discharges,
A product gas having one end located in the furnace body and the other end located outside the furnace body and having a plurality of openings at a position on the one end side in the vicinity of the fired product in the product gas generation region. Suction piping;
A blower for sucking the generated gas from the plurality of openings and flowing toward the other end of the generated gas suction pipe;
And a deodorizing device provided on the other end side for deodorizing the generated gas led to the other end side of the generated gas suction pipe at a predetermined temperature to deodorize the continuous firing furnace. The furnace body supports and conveys the fired product by a number of rollers rotated around an axis perpendicular to the transport direction of the fired product,
2. The continuous firing furnace according to claim 1, wherein a suction port that opens in a space provided below the plurality of rollers is provided connected to the exhaust device. The continuous firing furnace according to claim 1, wherein the generated gas suction pipe is inserted toward the high temperature side from the low temperature side opening of the furnace body located on the entrance side of the fired product. The continuous firing furnace according to claim 1, wherein the plurality of openings has a diameter that decreases from the low temperature side toward the high temperature side. The continuous firing furnace according to claim 1, wherein a guide plate for guiding the generated gas to the plurality of openings is provided along a longitudinal direction of the generated gas suction pipe.

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