WO2017166112A1 - Hot air drying system and method - Google Patents

Abstract

A hot air drying system and method. The hot air drying system comprises a hot air drying device (1), a waste gas burning device (3), and a solvent recycling device (2) configured to recycle an organic solvent in a waste gas exhausted by the hot air drying device (1). The hot air drying device (1) is provided with a first air inlet and a first air outlet. The solvent recycling device (2) is provided with a second air inlet and a second air outlet. The waste gas burning device (3) is provided with a third air inlet, a third air outlet, and a thermal energy outlet. The first air outlet is connected to the second air inlet. The second air outlet is connected to the third air inlet. The thermal energy outlet is connected to the hot air drying device (1). The hot air drying system and method has good energy saving and emission reduction effects.

Description

Hot air drying system and method Technical field

The invention relates to the technical field of energy saving and emission reduction, and particularly relates to a hot air drying system and method.

Background technique

The drying system is the main energy consumption unit of printing, compounding, coating, spraying and painting production equipment, and is also the main emission source of exhaust gas. The drying system efficiency is the core parameter of the performance evaluation index of production equipment. At present, most of the production equipments such as printing presses, laminating machines, coating machines, gluing machines, roll coating machines, and dryers on the market contain hot air drying systems, and VOC exhaust gas is contained in the process of hot air drying. VOC is the English abbreviation for volatile organic compounds. As environmental protection requirements become more stringent, there are many restrictions on heating methods, resulting in higher and higher heat costs. Coupled with the VOC emission charges and strict restrictions on excessive emissions, the pressure on companies using such equipment is also getting bigger.

At present, the common solution for reducing thermal energy consumption is to exchange heat between the exhaust of the drying equipment and the fresh air that is replenished, reduce the exhaust air temperature, and increase the temperature of the fresh air, and the energy saving effect depends on the exhaust air volume and heat exchange of the drying equipment. The area of the device, the heat exchange area is fixed, and the larger the exhaust air volume, the greater the heat exchange loss. Existing conventional VOC exhaust gas treatment methods include condensation, incineration, adsorption or absorption. The condensation method is to cool the exhaust gas to condense the VOC in the exhaust gas into a liquid and recover it, but generally, the VOC content of the exhaust gas treated by the condensation method is still difficult to reach the standard. The incineration method uses high temperature to decompose and oxidize VOC in the exhaust gas into carbon dioxide and water. When the VOC concentration is high, it will waste resources, and when the VOC concentration is low, additional heat energy is needed to maintain the incineration. The adsorption method and the absorption method utilize the characteristics of substances such as activated carbon and absorption liquid to capture VOC molecules in the exhaust gas, thereby reducing the VOC concentration in the exhaust gas, and the captured VOC can be recovered by desorption or desorption, but the process consumes A lot of heat.

In summary, the prior art still has the following technical problems: the treatment of VOC exhaust gas and the energy-saving treatment method lack systematic, the heat energy consumption is high, the VOC content is difficult to meet the standard, and it is difficult to fully integrate environmental protection and energy conservation.

Summary of the invention

It is an object of the present invention to provide a hot air drying system and method for overcoming the problems of high thermal energy consumption and difficulty in achieving VOC content in the prior art, and it is difficult to fully integrate environmental protection and energy saving.

In order to achieve the above object, the present invention provides a hot air drying system including a hot air drying device, an exhaust gas incineration device, and a solvent recovery device for recovering an organic solvent in the exhaust gas discharged from the hot air drying device; the hot air drying device is provided with a first The air inlet and the first air outlet, the solvent recovery device is provided with a second air inlet and a second air outlet, and the exhaust gas incineration device is provided with a third air inlet, a third air outlet and a thermal energy outlet; The first exhaust vent is connected to the second air inlet, the second exhaust vent is connected to the third air inlet, and the thermal energy outlet is connected to the hot air drying device.

Preferably, in order to facilitate the recovery of the organic solvent in the exhaust gas discharged from the large number of hot air drying devices, and at the same time help to reduce the exhaust air volume of the hot air drying device, further contributing to reducing the thermal energy consumption of the hot air drying device, the first The exhaust vent is disposed at a highest point of the VOC concentration of the hot air drying device.

As a preferred solution, in order to make the enterprise easy to implement and produce full-process monitoring, it is convenient to adjust the exhaust air volume of the hot air drying device according to the exhaust gas concentration to ensure that the exhaust gas concentration is below the safety limit, and it is convenient to implement single-point online monitoring of the highest VOC concentration point. A row of air outlets is provided with a VOC concentration detecting device.

Preferably, in order to save fuel consumption for exhaust gas temperature rise, the exhaust gas incineration device is a regenerative exhaust gas incineration device.

Preferably, in order to facilitate the transfer of heat of the exhaust gas incineration device to the hot air drying device by means of a carrier, thermal energy derived from the thermal energy outlet is delivered to the hot air drying device by heat transfer oil, steam, hot air or hot water.

As a preferred solution, in order to effectively reduce the hydrolysis and oxidation of the solvent during the recovery process The loss caused by the same is also advantageous for the subsequent solvent refining of the recovered solvent, which is treated by condensation recovery.

Preferably, in order to facilitate adjustment of the amount of intake of the air inlet at the first air inlet, the first air inlet is provided with a first regulating valve.

Preferably, when the exhaust air temperature of the hot air drying device is high, the air inlet of the first air inlet is facilitated to exchange heat with the air exhaust of the first air outlet, and the first air inlet is provided at the first air inlet. The heat exchanger for exchanging heat of the first exhaust port for heat exchange.

As a preferred solution, considering that the value of the recovered solvent is high or the exhaust gas emission amount is large, the recovery rate of the solvent is improved, the processing air volume of the exhaust gas incineration device is reduced, and the adjustment is low after the solvent recovery device is processed. The VOC exhaust gas is used as the air volume of the intake air at the first air inlet, the second air outlet is simultaneously connected to the first air inlet; and the second air outlet is provided with the first air inlet Two regulating valves.

Preferably, in order to facilitate the discharge of the exhaust gas reaching the standard, the third exhaust vent is connected with the exhaust cylinder.

The invention provides a hot air drying method based on a hot air drying system, comprising the following steps:

S1. The VOC exhaust gas discharged from the first exhaust vent of the hot air drying device enters the solvent recovery device through the second air inlet to be processed;

S2, after the solvent recovery device recovers most of the organic solvent in the exhaust gas, the VOC exhaust gas discharged through the second exhaust vent of the solvent recovery device is further sent to the exhaust gas incineration device for purification treatment;

S3. The heat generated by the waste gas incineration device during the treatment process is continuously supplied to the hot air drying device through the heat energy outlet.

Preferably, the first exhaust vent in the step S1 is disposed at a highest point of the VOC concentration of the hot air drying device.

The hot air drying system and method provided by the invention have the following technical effects: the VOC exhaust gas discharged from the hot air drying device is processed by the solvent recovery device, and is returned The majority of the organic solvent in the exhaust gas is collected, and the VOC concentration is lowered. The lower concentration of VOC exhaust gas discharged after being treated by the solvent recovery device is further purified by the exhaust gas incineration device, and the heat generated by the exhaust gas incineration device is maintained. The combustion is continued, and the remaining heat is supplied to the hot air drying device. The whole process realizes the full integration of environmental protection and energy saving. The hot air drying system adopting the technical scheme of the present invention adopts a hot air drying device, a solvent recovery device and an exhaust gas incineration device as one The system solves the problems of energy conservation and environmental protection from the perspective of the system, that is, realizes the recycling of organic solvents, and at the same time, the VOC is easy to reach the standard, and the heat energy consumption is reduced, thereby helping the enterprise to minimize the production cost.

DRAWINGS

1 is a skeleton view of a hot air drying system according to Embodiment 1 of the present invention;

2 is a skeleton diagram of a hot air drying system according to a second embodiment of the present invention.

In the figure: 1-hot air drying device, 11-first regulating valve, 12-VOC concentration detecting device, 13-heat exchanger, 14-film, 2-solvent recovery device, 21-solvent refining device, 22-second adjustment Valve, 3-exhaust gas incinerator, 4-exhaust cylinder.

detailed description

The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments:

Embodiment 1

As shown in FIG. 1 , the present invention provides a hot air drying system, comprising a hot air drying device 1, an exhaust gas incineration device 3, and a solvent recovery device 2 for recovering an organic solvent in the exhaust gas discharged from the hot air drying device 1; the hot air drying device 1 The first air inlet and the first air outlet are provided, the solvent recovery device 2 is provided with a second air inlet and a second air outlet, and the exhaust gas incineration device 3 is provided with a third air inlet, a third air outlet and a thermal energy outlet. Wherein, the first exhaust vent is connected to the second air inlet, the second exhaust vent is connected to the third air inlet, and the thermal energy outlet is connected to the hot air drying device 1.

Specifically, the first exhaust vent is disposed at the highest point of the VOC concentration of the hot air drying device 1, which is advantageous for recovering the organic solvent in the exhaust gas discharged from the large number of hot air drying devices 1, and helps to reduce the exhaust of the hot air drying device 1. Amount, further helping to reduce the hot air drying device 1 heat energy consumption. In addition, the VOC concentration detecting device 12 is disposed at the first exhaust vent, so that the enterprise can easily implement and monitor the whole process, and it is convenient to adjust the exhaust air volume of the hot air drying device 1 according to the exhaust gas concentration, and ensure that the exhaust gas concentration is below the safety limit, and is convenient. Single point online monitoring of the highest VOC concentration.

Specifically, the exhaust gas incineration device 3 uses a ceramic heat storage body to facilitate heating of the ceramic body to preheat the organic waste gas that subsequently enters the exhaust gas incineration device 3, thereby saving fuel consumption for heating the exhaust gas. The heat energy derived from the heat energy outlet is sent to the hot air drying device 1 by heat transfer oil, steam, hot air or hot water, so that the heat of the exhaust gas incinerator 3 can be transported to the hot air drying device 1 through the carrier.

In addition, the solvent recovery device 2 adopts a treatment method of condensation recovery, and the treatment method of condensation recovery can be a conventional conventional technology. Specifically, the condensation solvent recovery device can cool or pressurize the exhaust gas below the dew point temperature of the organic gas, so that Liquefaction to separate from the exhaust gas. The treatment method by condensation recovery can effectively reduce the loss caused by hydrolysis and oxidation in the recovery process of the solvent, and is also beneficial to the subsequent solvent purification of the recovered solvent.

A first regulating valve 11 is disposed at the first air inlet to facilitate adjustment of the amount of intake of the air at the first air inlet.

Further, the solvent recovered by the solvent recovery device 2 can be further purified by the solvent refining device 21 according to the needs of the user, thereby greatly reducing the solvent consumption of the user. It is worth mentioning that the solvent is purified by the solvent refining device 21. The method can employ conventional techniques of the prior art. In addition, the third exhaust vent is connected with the exhaust cylinder 4, so as to facilitate the discharge of the exhaust gas reaching the standard.

It is worth noting that the intake air at the first air inlet is to supplement the fresh air, and the amount of fresh air can be determined according to the highest value of the VOC concentration in the hot air drying device 1, that is, the VOC concentration of the exhaust gas discharged from the hot air drying device 1. This can help to minimize the amount of exhaust air from the hot air drying device 1 while ensuring safety. The hot air drying device 1 and the exhaust gas incineration device 3 can employ conventional conventional techniques. Further, the method of determining the highest point of the VOC concentration of the hot air drying device 1 can employ the conventional conventional techniques. In the process of implementation, the adjustment of the amount of intake air In the section, it is necessary to ensure that the VOC concentration of the exhaust gas is high, but does not exceed the concentration value corresponding to 25% of the lower explosion limit specified in the prior art, so as to ensure that the exhaust air volume of the hot air drying device 1 is further minimized under the safety condition. .

Further, the solvent recovery device 2 can also recover the solvent by absorption, adsorption, or the like. The exhaust gas incineration device 3 has a function of exhaust gas incineration and heat energy output. The exhaust gas incineration device 3 can be a regenerative thermal incineration device (RTO). The regenerative thermal incinerator is a prior art, and a common two-bed RTO, a three-bed RTO, a rotating RTO, and the like. The principle of regenerative thermal incineration is to heat the organic waste gas to above 760 °C, so that the VOC in the exhaust gas is oxidized and decomposed into carbon dioxide and water, and the treated exhaust gas can be discharged to the standard. The high-temperature gas generated by the oxidation flows through the ceramic regenerator, and the ceramic body is heated to "storage heat". This "heat storage" is used to preheat the organic exhaust gas that is subsequently entered, thereby saving fuel consumption for heating the exhaust gas. The heat recovery efficiency of the exhaust gas incineration device 3 is over 95%. Since the VOC generates heat during the oxidation process, when the VOC concentration reaches a very low value, the heat supply balance of the exhaust gas incineration device 3 itself can be realized without an external heat source, if the VOC When the concentration exceeds the value, heat can be left, and the remaining heat can be transferred to the hot air drying device 1 through a carrier such as heat transfer oil, steam, hot air or hot water.

Further, the exhaust gas incineration device 3 can also employ a rotary heat storage type exhaust gas incineration device. The rotary regenerative exhaust gas incineration device comprises an incinerator and a rotary reversing valve; in particular, the incinerator comprises a burner, an insulated casing and at least two sets of regenerators, each group of regenerators being enclosed with the insulated casing A balance chamber is formed, each of the balance chambers is enclosed to form a central space for the combustion chamber, the burner is installed at the center of the top of the combustion chamber, the heat storage body is provided with an air flow passage connecting the balance chamber and the combustion chamber, and the balance chamber is provided with a balance chamber inlet and outlet. Specifically, the rotary reversing valve comprises a valve body, a valve core and a driving device, and a certain gap between the valve body and the valve core, the driving device is connected with the central shaft of the valve core and drives the valve core to rotate, and between the valve core and the valve body The utility model is provided with an intake zone, an exhaust zone, a cleaning zone and at least two distribution zones, wherein the intake zone and the exhaust zone are respectively a space region in which the valve core separates the internal cavity of the valve body into two upper and lower parts, and the cleaning is performed. The area is a space area of the valve core close to the inner wall of the valve body, and the distribution area is a space area of the valve core away from the inner wall of the valve body; the valve body is provided with an air inlet port and an exhaust port communicating with the air inlet area; Exhaust vents connected to the area, and clear The inlet and outlet of the cleaning area connected to the sweeping area and the inlet and outlet of at least two distribution areas communicating with the distribution area; the inlet and outlet of each distribution area are respectively connected with the corresponding inlet and outlet of the balance chamber. Through the structure of the balance chamber and the combustion chamber, the level of the gas to be treated enters the center of the combustion chamber, and the oxidative decomposition decomposes horizontally into the ceramic regenerator. The rotary regenerative exhaust gas incineration device helps the exhaust gas incineration device 3 to operate stably and reliably, and the amount of the regenerator is greatly reduced, and the cost is reduced, which contributes to the heat generated by the exhaust gas incineration device 3 in addition to the regenerative combustion. The remaining heat is continuously supplied to the hot air drying device 1 continuously and steadily.

Embodiment 2

As shown in FIG. 2, the hot air drying system provided by another embodiment of the present invention is different from the first embodiment in that: the first air inlet is further provided with a heat exchange for exchanging air with the first air outlet. The heat exchanger 13 facilitates heat exchange between the intake air of the first air inlet and the exhaust air of the first air outlet when the exhaust air temperature of the hot air drying device 1 is high.

In addition, the difference between the embodiment and the first embodiment is that the second exhaust vent is connected to the first air inlet at the same time, and the solvent recovery is improved in consideration of the high value of the recovered solvent or the large exhaust gas emission. The rate is reduced to reduce the amount of air handled by the exhaust gas incineration device 3. Specifically, the lower concentration VOC exhaust gas discharged after being treated by the solvent recovery device 2 may directly enter the exhaust gas incineration device 3 for purification treatment, or a part of the fresh air may be added to the hot air drying device 1 as a fresh air, and the remaining portion may be incinerated into the exhaust gas. The device 3 is cleaned. In addition, a second regulating valve 22 is further disposed between the second exhaust vent and the first air inlet to facilitate adjustment of the lower VOC exhaust gas treated by the solvent recovery device 2 as the air volume of the intake air at the first air inlet.

For the second embodiment, the hot air drying system of the multi-functional machine is taken as an example to illustrate that the VOC emitted by the laminating machine during the drying process is ethyl acetate.

The fresh air enters the hot air drying device 1 from the first air inlet of the hot air drying device 1 of the multi-functional machine, and the VOC concentration in the device is distributed through the organization of the internal air flow, and the first air outlet of the hot air drying device 1 is set at the highest VOC concentration. Point. Specifically, the hot air drying device 1 is provided with a dried film 14, the first air inlet is disposed at the tail end of the hot air drying device 1 of the compound machine (ie, the discharge end of the dried film 14), and the first air outlet is disposed at the compound machine. of The front end of the hot air drying device 1 (i.e., the feed end of the dried film 14), such that the pressure difference caused by the exhaust fan causes the air flow to move in the opposite direction of the direction of movement of the dried film 14, and ultimately from the first exhaust The mouth is discharged. Since the VOC of the dried film 14 is gradually volatilized during the drying process, and the depth of the film is deeper along the moving direction of the film, the amount of VOC volatilized is reduced, so that the dry gas flow is reduced. The VOC concentration gradually increases in the opposite direction to the direction in which the film 14 is moved, and the concentration is highest near the feed end of the film 14 to be dried, that is, the first exhaust port. The hot air drying device 1 of the compound machine may be composed of a plurality of drying units connected in series, in order to ensure the formation of a pressure difference between the first air inlet and the first air outlet, and may also be in every two adjacent drying units. Air flow channels and fan traction are provided between. Specifically, taking the hot air drying device including three sets of drying units as an example, the hot air drying device 1 of the multifunction machine includes three drying units A, B, and C, and the dried film 14 is sequentially passed through the drying unit A, the drying unit B, and dried. Unit C. The drying unit comprises a drying box, a drying fan and a unit exhaust fan, the drying unit is provided with a unit air inlet and a unit air outlet, the unit air inlet is arranged near the discharging end of the drying unit, and the unit air outlet is arranged at the concentration of the drying unit. The highest point is near the feeding end of the drying unit, the unit exhaust port is connected to the inlet of the unit exhaust fan, the outlet of the exhaust fan of the drying unit C is connected to the inlet of the drying unit B, and the outlet of the exhaust fan of the drying unit B It is connected to the air inlet of the drying unit A. At this time, the air inlet of the drying unit C is the first air inlet of the hot air drying device 1 of the composite machine, and the air outlet of the drying unit A is the hot air drying device 1 of the composite machine. A row of air outlets.

The higher concentration VOC exhaust gas discharged from the hot air drying device is subjected to heat exchange with the fresh air through the heat exchanger 13, and then enters the solvent recovery device 2. The solvent recovery device 2 of the present embodiment is a low-temperature condensation recovery device, and has a target cooling temperature of -40 °C. The lower concentration VOC exhaust gas treated by the solvent recovery device 2 is divided into two parts, one portion enters the hot air drying device 1 as fresh air, and the other portion enters the exhaust gas incineration device 3 for purification treatment. The exhaust gas incineration device 3 has a thermal energy output function, and its thermal energy is output to the hot air drying device 1 through the heat transfer oil, and the heat transfer oil can be transported by means of a hot and cold cycle. Exhaust gas incinerator 3 At startup, the fuel can also be preheated to a high temperature above 760 °C.

It is worth noting that the 25% lower limit of the ethyl acetate explosion corresponds to a concentration of 5450 PPM, about 21.4 g/Nm ³ , from which it can be determined that the total fresh air volume should be greater than 1400 Nm ³ /h. Total fresh air designed to 2000Nm ³ / h, where 1000Nm ³ / h fresh air outside the apparatus, 1000Nm ³ / h for the low concentration of the exhaust gas processed by the solvent recovery device 2. Based on the saturated vapor pressure of ethyl acetate, the concentration of ethyl acetate in the exhaust gas after cooling the exhaust gas to -40 ° C was about 1900 PPM, about 7.5 g/Nm ³ . From this, it is estimated that the VOC concentration of the exhaust gas discharged from the solvent recovery device 2 is about 4770 PPM, and the concentration of about 18.8 g/Nm ^{3 is} close to but less than 25% of the lower limit of the explosion of the ethyl acetate, so that the system is safe and the air volume is appropriate.

After the 2000 Nm ³ /h concentration of 18.8 g/Nm ³ of the ethyl acetate-containing waste gas was cooled to -40 ° C by the solvent recovery device 2, ethyl acetate was recovered at about 22.6 Kg / h, and the hot air drying system of the present invention was tested to pass the solvent. The purity of the ethyl acetate recovered by the recovery device 2 is 98% or more, and can be repeatedly used after being simply treated by the solvent refining device 21. In the present embodiment, the operating power of the solvent recovery equipment is about 35 KW.

Exhaust gas through the solvent recovery process 2 has 1000Nm ³ / h of exhaust gas into the incinerator apparatus 3 performs the regenerative combustion, in general, the exhaust gas concentration of ethyl acetate containing 2g / Nm ^3, the exhaust gas incineration added 3 may not be required The extra heat, at this time, the ethyl acetate exhaust gas concentration was 7.5 g/Nm ³ , and it was estimated that the exhaust gas incineration device 3 can have a residual heat output of about 39 KW when oxidizing and decomposing the VOC gas. Further, the heat of the hot air drying device 1 can also be supplied by supplementing the combustion fuel by the exhaust gas incineration device 3.

Further, the present invention provides a hot air drying method based on a hot air drying system, comprising the steps of:

S1. The VOC exhaust gas discharged from the first exhaust vent of the hot air drying device 1 enters the solvent recovery device 2 through the second air inlet for processing;

S2, after the solvent recovery device 2 recovers most of the organic solvent in the exhaust gas, the VOC exhaust gas discharged through the second exhaust vent of the solvent recovery device 2 is further sent to the exhaust gas incineration device 3 for purification treatment;

S3. The heat generated by the waste gas incinerator 3 during the process is continuously supplied to the hot air drying device 1 through the heat energy outlet.

Preferably, the first exhaust vent in step S1 is disposed at the highest point of the VOC concentration of the hot air drying device 1.

The hot air drying system and method of the technical scheme of the invention recovers most of the organic solvent in the exhaust gas, realizes the recycling of the organic solvent, reduces the VOC concentration, the VOC is easy to reach the standard, and reduces the heat energy consumption, and the whole process realizes environmental protection and The full integration of energy conservation helps enterprises to minimize production costs and provide enterprises with a “green manufacturing system” that is energy-saving and environmentally friendly.

The above is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention. It should also be considered as the scope of protection of the present invention.

Claims (12)

A hot air drying system, comprising: a hot air drying device, an exhaust gas incineration device, and a solvent recovery device for recovering an organic solvent in the exhaust gas discharged from the hot air drying device; The hot air drying device is provided with a first air inlet and a first air outlet, the solvent recovery device is provided with a second air inlet and a second air outlet, and the exhaust gas incineration device is provided with a third air inlet and a third Exhaust vent and thermal energy outlet; The first exhaust vent is connected to the second air inlet, the second exhaust vent is connected to the third air inlet, and the thermal energy outlet is connected to the hot air drying device. The hot air drying system according to claim 1, wherein said first exhaust vent is provided at a highest point of VOC concentration of said hot air drying device. The hot air drying system according to claim 2, wherein said first exhaust vent is provided with a VOC concentration detecting means. The hot air drying system according to claim 1, wherein said exhaust gas incineration device is a regenerative exhaust gas incineration device. The hot air drying system according to claim 1, wherein the heat energy derived from the thermal energy outlet is delivered to the hot air drying device by heat transfer oil, steam, hot air or hot water. The hot air drying system according to any one of claims 1 to 5, wherein the solvent recovery device employs a treatment method of condensation recovery. The hot air drying system according to any one of claims 1 to 5, characterized in that the first air inlet is provided with a first regulating valve. The hot air drying system according to claim 7, wherein the first air inlet is provided with a heat exchanger for exchanging heat with the exhaust air of the first air outlet. The hot air drying system according to any one of claims 1 to 5, wherein the second exhaust vent is simultaneously connected to the first air inlet; the second exhaust vent and the first inlet A second regulating valve is arranged between the tuyes. The hot air drying system according to any one of claims 1 to 5, characterized in that the third exhaust vent is connected to the exhaust cylinder. A hot air drying method according to the hot air drying system of claim 1, comprising the steps of: S1. The VOC exhaust gas discharged from the first exhaust vent of the hot air drying device enters the solvent recovery device through the second air inlet to be processed; S2, after the solvent recovery device recovers most of the organic solvent in the exhaust gas, the VOC exhaust gas discharged through the second exhaust vent of the solvent recovery device is further sent to the exhaust gas incineration device for purification treatment; S3. The heat generated by the waste gas incineration device during the treatment process is continuously supplied to the hot air drying device through the heat energy outlet. The hot air drying method according to claim 11, wherein the first exhaust vent in the step S1 is disposed at a highest point of the VOC concentration of the hot air drying device.

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