JP2003265921A - Exhaust gas treatment equipment and exhaust gas treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide exhaust gas treatment equipment which allows a deodorizer to be made smaller in size and to provide an exhaust gas treatment method. <P>SOLUTION: In this exhaust gas treatment equipment 14, exhaust gas discharged from a drier 1 in which an object to be dried is directly heated by steam and is dried is treated. This exhaust gas treatment equipment is provided with a cooler 19 which cools the exhaust gas discharged from the drier 1, the deodorizer 17 which deodorizes one part of the exhaust gas from the cooler 19 and dilution gas supplying lines 15, 9, 2 which supply the remaining part of the exhaust gas from the cooler 19 to the drier 1 as dilution gas of the steam. Therein, one part of the exhaust gas cooled by the cooler 19 is deodorized by the deodorizer 17 and the remaining part is supplied to the drier 1 as the dilution gas of the steam through the supplying lines 15, 9, 2. In such a manner, one part of the exhaust gas to be originally deodorized by the deodorizer 17 is used as the dilution gas of the steam and, therefore, the amount of the exhaust gas to be deodorized by the deodorizer 17 can be adequately reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treatment facility and an exhaust gas treatment method, and more particularly, to treating exhaust gas discharged from a direct heating type drying apparatus for directly heating and drying an object to be dried with steam. Exhaust gas treatment equipment and exhaust gas treatment method.

[0002]

2. Description of the Related Art As a drying device for drying dehydrated sludge, food waste, etc., a direct heating type drying device for directly drying an object to be dried by steam has been known. In this direct heating type drying device, usually, the dehydrated sludge is put into a drying pot and steam is introduced, and the dehydrated sludge is dried by directly contacting the steam with the dehydrated sludge.

However, when the dehydrated sludge is dried, a mist may be generated from the dehydrated sludge, and the mist may reattach to the dried dehydrated sludge. Therefore, in order to prevent reattachment of mist, in addition to steam, generally, a dilution gas and a high-temperature combustion gas for heating the dilution gas are introduced into the drying pot.

When the dehydrated sludge is dried in this way, steam,
Exhaust gas containing mist, diluent gas, combustion gas, and dust is generated. In particular, the diluent gas and the combustion gas contain a malodorous component such as ammonia. Therefore, an exhaust gas treatment facility for treating such exhaust gas is required.

FIG. 7 is a flow chart showing an example of conventional exhaust gas treatment equipment. As shown in FIG. 7, in the exhaust gas treatment facility 100, the exhaust gas discharged from the direct heating type drying device 101 is usually a cyclone or a bag filter 1.
The dust is removed at 02, and is cooled by the heat exchanger 103, so that the vapor and mist in the exhaust gas are condensed and removed. Then, the finally remaining diluent gas and combustion gas are sent to the deodorizing device 104, the malodorous components are removed, and the gas is released into the atmosphere as clean gas.

[0006]

However, the above-mentioned conventional exhaust gas treatment facility 100 has the following problems.

That is, in the exhaust gas treatment facility 100, the exhaust gas discharged from the direct heating type drying device 101 is dust-removed by the cyclone or the bag filter 102, and steam and mist are condensed and removed by the heat exchanger 103, but heat exchange is performed. Exhaust gas discharged from the container 103 contains a large amount of combustion gas and diluent gas. Therefore, this large amount of exhaust gas is deodorized by the deodorizing device 104, and the deodorizing device 104 is inevitably large.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust gas treatment facility and an exhaust gas treatment method capable of downsizing a deodorizing device.

[0009]

In order to solve the above problems, the present invention provides an exhaust gas treatment facility for treating exhaust gas discharged from a direct heating type drying device for directly heating and drying an object to be dried by steam, A cooling device for cooling the exhaust gas discharged from the direct heating type drying device, a deodorizing device for deodorizing a part of the exhaust gas discharged from the cooling device, and a balance of the exhaust gas discharged from the cooling device for the steam. And a diluent gas supply line for supplying the diluent gas to the direct heating type drying device.

According to the present invention, the material to be dried is directly heated by the steam in the direct heating type drying device to dry the material to be dried. At this time, exhaust gas containing steam, mist, and dilution gas is discharged from the direct heating type drying device. This exhaust gas is cooled by a cooling device, and the mist and vapor in the exhaust gas are condensed and removed. Then, a part of the exhaust gas discharged from the cooling device is deodorized by the deodorizing device, and the remaining part is directly supplied to the heating-type drying device as a diluent gas of vapor through a diluent gas supply line. In this way, a part of the exhaust gas is circulated and used as a diluent gas for steam without being deodorized. Therefore, the amount of exhaust gas to be deodorized by the deodorizing device can be sufficiently reduced.

The exhaust gas treatment facility preferably further comprises a heat exchanger for cooling the exhaust gas passing between the direct heating type drying device and the cooling device and for heating the exhaust gas passing through the dilution gas supply line.

According to the present invention, the heat exchanger and the cooling device can sufficiently cool the high-temperature exhaust gas discharged from the direct heating type drying device. Therefore, in the deodorizing device, the removal rate of the malodorous component in the exhaust gas is improved.
Further, the heat exchanger heats the exhaust gas passing through the dilution gas supply line to raise the temperature of the exhaust gas passing through the dilution gas supply line. Therefore, it is not necessary to use extra energy to raise the temperature of the diluent gas.

The exhaust gas treatment facility comprises a pressure measuring device for measuring the pressure of the exhaust gas discharged from the direct heating type drying device in the exhaust gas transfer line or the dilution gas supply line,
A flow rate adjusting valve that adjusts the flow rate of the exhaust gas flowing from the cooling device to the deodorizing device, and a control device that controls the flow rate adjusting valve so that the pressure becomes constant based on the pressure measured by the pressure measuring device. Is preferably further provided.

According to the present invention, the pressure in the exhaust gas transfer line or the dilution gas supply line is made constant by the control device based on the pressure in the exhaust gas transfer line or the dilution gas supply line measured by the pressure measuring device. The flow rate adjusting valve is controlled to adjust the flow rate of the exhaust gas flowing from the cooling device to the deodorizing device. Therefore, the exhaust gas transfer line or the diluent gas supply line need not be in a negative pressure or positive pressure state, and the exhaust gas transfer line or the diluent gas supply line need not have a pressure resistant structure.

Further, the present invention provides an exhaust gas treatment method for treating exhaust gas discharged from a direct heating type drying device for directly heating and drying an object to be dried with steam, wherein the exhaust gas discharged from the direct heating type drying device is treated. A cooling step of cooling, a deodorizing step of deodorizing a part of the exhaust gas cooled in the cooling step with a deodorizing device, and a balance of the exhaust gas cooled in the cooling step is supplied as dilution gas to the direct heating dryer. And a diluting gas supply step for performing the same.

According to this exhaust gas treatment method, the material to be dried is directly heated by the steam in the direct heating type drying device,
The material to be dried is dried. At this time, exhaust gas containing steam, mist, and dilution gas is discharged from the direct heating type drying device. This exhaust gas is cooled, and the mist and vapor in the exhaust gas are condensed and removed. Then, a part of the cooled exhaust gas is deodorized by the deodorizing device, and the rest is directly supplied to the heating-type drying device as a vapor dilution gas. in this way,
Since a part of the exhaust gas is not deodorized and is circulated and used as a diluent gas of steam, the amount of the exhaust gas to be deodorized by the deodorizing device can be sufficiently reduced.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. In all the drawings, the same or equivalent constituents will be referred to with the same signs.

(First Embodiment) FIG. 1 is a perspective view schematically showing the structure of a direct heating type drying device, and FIG. 2 is a partial sectional view showing the internal structure of the direct heating type drying device of FIG. . As shown in FIG. 1, the direct heating type drying device 1 includes a cylindrical sludge drying pot 3, and the sludge drying pot 3 has a cylindrical portion 3a.
And side walls 3b and 3c provided on both sides thereof. At the bottom of the side wall 3b of the sludge drying pot 3, a sludge inlet 3 is provided.
d is formed, and the sludge feeder 4 for charging the dehydrated sludge into the sludge dryer 3 is connected to the sludge inlet 3d. A sludge transfer pipe 10 is connected to the sludge feeder 4,
The sludge feeder 4 is actuated by the motor 5 and feeds the dehydrated sludge introduced from the sludge transfer pipe 10 into the sludge feeder 4 into the sludge drying pot 3. The sludge feeder 4 includes, for example, a pipe and a screw (not shown) rotatably arranged inside the pipe, and the screw includes a motor 5
Are connected.

Further, a steam inlet 3e is formed in the cylindrical portion 3a of the sludge dryer 3 in the vicinity of the sludge inlet 3d, and a steam transfer pipe 2 is connected to the steam inlet 3e. A pressure control valve (not shown) that controls the pressure of steam is installed in the steam transfer pipe 2. Therefore, the steam can be introduced into the sludge drying pot 3 in a state where the pressure is adjusted.

Here, as shown in FIG. 2, the steam transfer pipe 2 is provided with an injection nozzle 7 in the interior thereof and in the vicinity of the steam introduction port 3e. It is designed to be sprayed on the dehydrated sludge.

In addition, the vapor transfer pipe 2 is provided with an injection nozzle 7
A high temperature gas suction port 8 is formed in the vicinity of, and a branch pipe 9 is connected to the high temperature gas suction port 8. The branch pipe 9 is provided so as to be sealed with respect to the vapor transfer pipe 2, and an auxiliary heat source burner 13 is provided at the tip of the branch pipe 9. The auxiliary heat source burner 13 burns the fuel gas to generate high-temperature combustion gas.
Further, a branch line 15 is connected to the branch pipe 9 so that the diluent gas is supplied from the branch line 15 to the branch pipe 9.

Therefore, the fuel gas is the burner 1 for the auxiliary heat source.
When the fuel gas is ignited and the fuel gas is ignited, the fuel gas is combusted to generate high temperature combustion gas. At this time, if the diluent gas is introduced from the branch line 15 into the branch pipe 9,
The dilution gas is in a high temperature state (for example, 3
50 to 400 ° C.). Here, the reason why the diluent gas is heated to a high temperature by burning the fuel gas is that the air is heated to about the temperature of the steam since the steam is cooled and condensed when the air is at room temperature. . This high temperature dilution gas is sucked into the inside of the steam transfer pipe 2 through the high temperature gas suction port 8 from the branch pipe 9 by the ejector effect when the steam is injected from the injection nozzle 7, and the high temperature dilution gas dilutes the steam. , The dryness of steam is increased.
Therefore, it becomes possible to make the steam have a higher temperature and a higher degree of dryness.

FIG. 3 is a flow chart showing a first embodiment of the exhaust gas treatment equipment of the present invention. As shown in FIG. 3, the exhaust gas treatment facility 14 includes a direct heating type drying device 1, and a bag filter 12 is connected to the direct heating type drying device 1 via a pipe 11. Here, as shown in FIG. 1, the pipe 11 guides the exhaust gas containing the dried matter obtained in the sludge drying pot 3 to the bag filter 12, and extends from substantially the center of the side wall 3 c of the sludge drying pot 3. . The bag filter 12 removes dry sludge in the exhaust gas, that is, removes dust from the exhaust gas. Although the bag filter 12 is used in FIG. 1, another device may be used instead of the bag filter 12 as long as it is a device capable of separating exhaust gas and dried sludge. Examples of such a device include a gravity settler and a cyclone.

A deodorizing device 17 is connected to the bag filter 12 via an exhaust gas transfer line 16. The deodorizing device 17 is for removing a malodorous component in the exhaust gas, and is composed of, for example, an activated carbon tower filled with activated carbon.

In the exhaust gas transfer line 16, a suction fan 18, a cooling device 19 and a flow rate adjusting valve 20 are sequentially provided from the bag filter 12 side toward the deodorizing device 17. The suction fan 18 is for transferring the exhaust gas, and the cooling device 19 is for cooling the exhaust gas passing through the exhaust gas transfer line 16 to condense steam and mist in the exhaust gas. , By introducing the refrigerant (cooling water) sent from the cooling tower 22 into the cooling device 19. The refrigerant, which has recovered the heat from the exhaust gas in the cooling device 19, is returned to the cooling tower 22 to be cooled.

The branch line 15 described above extends from the portion of the exhaust gas transfer line 16 between the cooling device 19 and the deodorizing device 17, and its tip is connected to the branch pipe 9. Therefore, it is possible to supply the exhaust gas passing through the exhaust gas transfer line 16 to the branch pipe 9 via the branch line 15 as a vapor dilution gas. The branch line 15, a part of the branch pipe 9 and a part of the vapor transfer pipe 2 constitute a diluent gas transfer line.

The exhaust gas treatment facility 14 further includes a heat exchanger 21 for heat recovery, which cools a portion of the exhaust gas transfer line 16 between the bag filter 12 and the cooling device 19 and heats the branch line 15. It is preferable. In this case, the heat exchanger 21 and the cooling device 19 can cool the high temperature exhaust gas directly discharged from the heating type drying device 1 to near room temperature. Therefore, the deodorizing device 17
In the above, the adsorption rate of the malodorous component in the exhaust gas is improved. On the other hand, the branch line 15 is heated by the heat exchanger 21,
The temperature of the diluent gas passing through the branch line 15 is increased. Therefore, it is not necessary to supply the fuel gas to the auxiliary heat source burner 13 to increase the temperature of the diluent gas, and the running cost can be reduced. That is, in the heat exchanger 21,
The exhaust gas in the branch line 15 can be heated by utilizing the heat obtained from the exhaust gas when the exhaust gas in the exhaust gas transfer line 16 is cooled. Therefore, the running cost for heating can be sufficiently reduced.

Next, an exhaust gas treatment method in the exhaust gas treatment facility 14 will be described.

First, in the drying device 1, for example, dehydrated sludge is introduced into the sludge feeder 4 through the sludge transfer pipe 10 as shown in FIG. At this time, when the motor 5 is operated, the introduced dewatered sludge is put into the sludge dryer 3 by the sludge feeder 4.

On the other hand, steam is introduced into the drying pot 3 from the steam transfer pipe 2. At this time, the steam is in a high temperature state, and this high-temperature steam is directly injected from the injection nozzle 7 toward the dehydrated sludge A as shown in FIG. 2, whereby the dehydrated sludge A is dried.

When steam is injected into the dehydrated sludge, the auxiliary heat source burner 13 in the branch pipe 9 is supplied with a mixed gas of fuel gas (for example, city gas) and air. At this time, when the fuel gas is ignited, combustion of the fuel gas occurs and high-temperature combustion gas is generated. At this time, when the diluent gas is introduced from the branch line 15 into the branch pipe 9, the diluent gas is heated to a high temperature by the heat of the combustion gas. Then, this high-temperature dilution gas is sucked into the steam transfer pipe 2 from the branch pipe 9 through the high-temperature gas suction port 8 due to the ejector effect when the steam is injected from the injection nozzle 7, and the high-temperature dilution gas generates the steam. The dryness of the steam that is diluted and injected from the injection nozzle 7 is increased. As a result, the steam becomes hotter and the dryness increases, and the dehydrated sludge is dried by the hot steam, so that the drying efficiency of the dehydrated sludge is further improved.

The pressure of the steam injected from the injection nozzle 7 is preferably adjusted to 0.3 to 0.5 MPa (gauge pressure) by a pressure adjusting valve. In this case, a high-speed airflow is generated by the steam injected from the injection nozzle 7, and a shock wave is generated in the sludge drying pot 3. Then, the dewatered sludge is crushed by the shock wave and the high-speed airflow, and at the same time, the sludge is dried and mixed in the sludge drying pot 3 at high speed. For this reason, the surface area per unit volume of the dehydrated sludge becomes large, and the drying efficiency of the dehydrated sludge becomes higher.

The dehydrated sludge thus sprayed with steam rotates along the circumferential surface 3a of the sludge drying pot 3. Then, as the water content of the dehydrated sludge decreases, the dehydrated sludge becomes lighter,
Centrifugal force becomes smaller. Then, the dewatered sludge gathers in the substantially center of the sludge drying pot 3, and is guided to the bag filter 12 through the pipe 11 together with the gas, and the bag filter 12 separates the dust-removed exhaust gas.

The separated exhaust gas is, as shown in FIG.
It is transferred through the exhaust gas transfer line 16 by the suction fan 18 and cooled by the heat exchanger 21. This lowers the temperature of the exhaust gas. Subsequently, the exhaust gas is transferred to the exhaust gas transfer line 16
And is cooled by the cooling device 19 (cooling step). As a result, the vapor and mist in the exhaust gas are condensed and removed, leaving almost only air. That is, the temperature of the exhaust gas is lowered to around room temperature, and the amount of the exhaust gas is sufficiently reduced by the liquefaction of steam and mist.

A part of the exhaust gas cooled by the cooling device 19 is deodorized by the deodorizing device 17 (deodorizing step),
Most of the remaining portion is supplied to the branch pipe 9 via the branch line 15 as a diluent gas of vapor in the drying device 1. Then, the dilution gas is brought to a high temperature state by the combustion gas and directly supplied to the heating type drying device 1 through the steam supply pipe 2 (dilution gas supply step). At this time, the flow rate of the exhaust gas transferred from the cooling device 19 to the deodorizing device 17 is adjusted by the flow rate adjusting valve 20 so as to be equal to the flow rate of the combustion gas.

As described above, most of the exhaust gas is circulated and used as the diluent gas of the steam in the drying device 1 without being deodorized. Therefore, it is not necessary to take in the dilution gas from the atmosphere, and the amount of exhaust gas to be deodorized by the deodorizing device 17 can be sufficiently reduced. Therefore, the deodorizing device 17 can be downsized, and the equipment cost can be greatly reduced.

(Second Embodiment) Next, a second embodiment of the exhaust gas treatment equipment of the present invention will be described.

FIG. 4 is a flow chart showing a second embodiment of the exhaust gas treatment equipment of the present invention. As shown in FIG. 4, the exhaust gas treatment equipment 30 of the present embodiment differs from the exhaust gas treatment equipment 14 of the first embodiment in that a scrubber 31 is used as the cooling device 19.

As shown in FIG. 4, the scrubber 31 has a cooling tower 32, and water is stored at the bottom of the cooling tower 32. The bottom and top of the cooling tower 32 are connected by a water supply line 33, and the water supply line 33 is connected to the pump 3
4 are installed. Therefore, by the operation of the pump 34, water can be pumped from the bottom of the cooling tower 32 through the water supply line 33 to the upper portion of the cooling tower 32 for circulation and use. On the other hand, the first exhaust gas transfer line 16a is connected to the side wall of the cooling tower 32, and the exhaust gas cooled by the heat exchanger 21 is introduced into the cooling tower 32 via the first exhaust gas transfer line 16a. . A second exhaust gas transfer line 16b extends from the top of the cooling tower 32, and its tip is connected to the deodorizing device 17. In the cooling tower 32, steam introduced through the piping of the first exhaust gas transfer line 16a,
High-temperature exhaust gas containing mist and dilution gas is water supply line 3
It is cooled to room temperature by the water supplied from No. 3. Therefore, the vapor and mist in the exhaust gas are condensed and accumulated at the bottom of the cooling tower 32.
More extracted. The extracted condensed water is supplied to a wastewater treatment facility (not shown). Further, the temperature of the water accumulated at the bottom of the cooling tower 32 rises due to the high-temperature exhaust gas, so the water is cooled by the cooling tower 22 and the temperature is maintained at about room temperature.

Then, a part of the cooled exhaust gas is
It is transferred to the deodorizing device 17 through the exhaust gas transfer line 16b, is deodorized by the deodorizing device 17, and the rest is the branch line 1
It is supplied to the drying device 1 through 5, the branch pipe 9, and the vapor transfer pipe 2. Therefore, as in the case of the first embodiment, the deodorizing device 17 can be downsized, and the equipment cost can be significantly reduced.

(Third Embodiment) Next, a third embodiment of the exhaust gas treatment equipment of the present invention will be described.

FIG. 5 is a flow chart showing a third embodiment of the exhaust gas treatment equipment of the present invention. As shown in FIG. 5, the exhaust gas treatment equipment 40 of the present embodiment is based on the pressure measuring device 41 provided in the branch line 15 and the pressure measured by the pressure measuring device 41, and the flow rate so that this pressure becomes constant. It differs from the exhaust gas treatment equipment 14 of the first embodiment in that it further includes a control device 42 that controls the adjustment valve 20.

According to the exhaust gas treatment facility 40, the pressure in the branch line 15 is kept constant (for example, atmospheric pressure) by the control device 42 based on the pressure in the branch line 15 measured by the pressure measuring device 41. The flow rate adjusting valve 20 is controlled to adjust the flow rate of the exhaust gas flowing from the cooling device 19 to the deodorizing device 17. Therefore, the branch line 15 does not have to be in a negative pressure or positive pressure state, and the branch line 15 does not have to have a pressure resistant structure. Therefore, the installation cost can be reduced. The pressure measuring device 41 may be provided in the exhaust gas transfer line 16. In this case, the control device 42 controls the exhaust gas transfer line 1 based on the pressure in the exhaust gas transfer line 16 measured by the pressure measuring device 41.
The flow rate adjusting valve 20 is controlled so that the pressure in 6 is constant (for example, atmospheric pressure), and the deodorizing device 1 is removed from the cooling device 19.
The flow rate of the exhaust gas flowing through 7 is adjusted.

The present invention is not limited to the above first to third embodiments. For example, in the said 1st-3rd embodiment, the branch pipe 9 is connected to the vapor transfer pipe 2, the branch line 15 is connected to the branch pipe 9, and the mixed gas of steam and a dilution gas is supplied to the drying device 1. However, as shown in FIG. 6, steam and diluent gas may be separately supplied to the drying device 1. In this case, since the branch pipe 9 is directly connected to the sludge drying pot 3 of the drying device 1 and the branch line 15 is connected to this branch pipe 9, the dilution gas supply line is the branch line 15 and a part of the branch pipe 9. It will be composed of.

[0045]

As described above, according to the exhaust gas treatment equipment and the exhaust gas treatment method of the present invention, most of the exhaust gas is
Since it is not deodorized and is directly circulated and used as a diluent gas of steam in the heating type drying device, the amount of exhaust gas to be deodorized by the deodorizing device can be sufficiently reduced and the deodorizing device can be downsized.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a direct heating type drying device.

FIG. 2 is a partial cross-sectional view showing the internal structure of the direct heating type drying device of FIG.

FIG. 3 is a flowchart showing a first embodiment of the exhaust gas treatment equipment of the present invention.

FIG. 4 is a flowchart showing a second embodiment of the exhaust gas treatment equipment of the present invention.

FIG. 5 is a flowchart showing a third embodiment of the exhaust gas treatment equipment of the present invention.

FIG. 6 is a flowchart showing a fourth embodiment of the exhaust gas treatment equipment of the present invention.

FIG. 7 is a flowchart showing an example of conventional exhaust gas treatment equipment.

[Explanation of symbols]

1 ... Direct heating type drying device, 2 ... Steam transfer pipe (diluting gas supply line), 9 ... Branch pipe (diluting gas supply line),
14, 30, 40 ... Exhaust gas treatment facility, 15 ... Branch line (diluting gas supply line), 17 ... Deodorizing device, 19 ... Cooling device, 20 ... Flow control valve, 21 ... Heat exchanger, 41 ...
Pressure measuring device, 42 ... Control device, A ... Dewatered sludge (material to be dried).

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F26B 21/00 F term (reference) 3L113 AC04 AC05 AC40 AC87 BA39 CA10 CB23 DA14 4C080 AA05 BB02 CC01 HH05 JJ03 KK08 LL02 MM05 QQ17 4D002 AB02 AC10 BA04 BA13 BA14 CA07 DA41 4D059 AA00 BD07 CA14 CA16

Claims (4)

[Claims] 1. An exhaust gas treatment facility for treating exhaust gas discharged from a direct heating type drying device which directly heats and dries an object to be dried by steam, and cooling for cooling the exhaust gas discharged from the direct heating type drying device. Device, a deodorizing device for deodorizing a part of the exhaust gas discharged from the cooling device, and a diluent gas that supplies the remainder of the exhaust gas discharged from the cooling device to the direct heating type drying device as the diluent gas of the vapor An exhaust gas treatment facility comprising: a supply line. 2. A heat exchanger for cooling the exhaust gas passing between the direct heating type drying device and the cooling device and heating the exhaust gas passing through the dilution gas supply line. Exhaust gas treatment facility described in. 3. A pressure measuring device for measuring the pressure of the exhaust gas discharged from the direct heating type drying device in the exhaust gas transfer line or the dilution gas supply line, and the flow rate of the exhaust gas flowing from the cooling device to the deodorizing device. The flow control valve for adjusting, and the control device for controlling the flow control valve so that the pressure becomes constant based on the pressure measured by the pressure measuring device, further comprising: Two
Exhaust gas treatment facility described in. 4. An exhaust gas treatment method for treating exhaust gas discharged from a direct heating type drying device which directly heats and dries an object to be dried by steam, and cooling for cooling the exhaust gas discharged from the direct heating type drying device. Step, a deodorizing step of deodorizing a part of the exhaust gas cooled in the cooling step with a deodorizing device, and supplying the rest of the exhaust gas cooled in the cooling step to the direct heating dryer as a dilution gas of the steam And a diluting gas supply step for performing the exhaust gas treatment method.