Hot air circulation tobacco curing system with heat recoverer

Abstract

The utility model discloses a hot air circulation tobacco curing system with a heat recoverer. The hot air circulation tobacco curing system comprises a heating furnace, an air supply pipe, a tobacco curing room, an air return pipe, the heat recoverer, an air return bypass, a heating furnace front air return pipe and an air feeder. The air supply amount of circulating hot air is adjusted by the air supply gate. The air supply temperature of circulating hot air is increased through the heating furnace. The tobacco curing strength in the tobacco curing barn is jointly controlled through the circulating hot air supply temperature and the air supply amount. A large amount of moisture is generated in the tobacco baking process and enters circulating hot air, and the circulating hot air releases waste heat in the heat recoverer in an air return mode and then is discharged. Fresh air with small moisture content is heated by absorbing heat released by return air through the heat recoverer and then enters hot air circulation. The energy-saving effect is achieved, meanwhile, the purpose of dehumidifying is achieved, the tobacco drying speed is high, the tobacco curing period is shortened, and the tobacco curing quality is improved.

Description

Technical Field

[0001] The present invention belongs to the field of tobacco drying equipment, and particularly relates to a hot air circulation tobacco baking system with a heat recovery device, which has small temperature fluctuations of circulating hot air, strong moisture exhaust capacity, obvious energy-saving effect, can avoid the occurrence of green tips of baked tobacco, and shorten the tobacco baking cycle. Background Art

[0002] China is a major tobacco-growing country in the world, with high tobacco yields and a large amount of flue-cured tobacco every year. During the tobacco baking process, hot air (hot air, the same below) is usually used to heat it to vaporize and remove the internal moisture, and finally form the production raw material for the cigarette industry. During the tobacco baking process, the tobacco baking house is a key facility and also the main energy-consuming facility. The temperature and humidity conditions in each part of the tobacco baking house, as well as the hot air flow rate, will directly affect the baking quality and process of tobacco.

[0003] Currently, during the tobacco baking process, there are problems such as poor stability in adjusting the temperature and humidity in the tobacco baking house, large temperature and humidity differences between the upper and lower parts of the tobacco baking area, and often large color differences and low quality in the baked tobacco leaves; during the tobacco baking process, moisture is only exhausted through the skylight and floor hole when the humidity in the tobacco baking house is too high, with weak moisture exhaust capacity, a long tobacco baking cycle, and it is easy to cause the phenomenon of green tips of baked tobacco; during the tobacco baking process, the hot air directly discharges after baking the tobacco, without recovering the waste heat of the discharged hot air, resulting in energy waste.

[0004] In view of the above problems, it is necessary to improve the existing tobacco baking technology and propose a hot air circulation tobacco baking system with a heat recovery device. Summary of the Invention

[0005] The purpose of the present invention is to provide a hot air circulation tobacco baking system with a heat recovery device in view of the deficiencies of the prior art. For this tobacco baking house and system, the circulating hot air is heated and raised in temperature in the heating furnace, the tobacco is baked in the tobacco baking house, the return air of the circulating hot air recovers the waste heat through the heat recovery device, and at the same time, the moisture exhaust process is completed. In addition, the humidity in the tobacco baking house is controlled by using the return air bypass gate.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions.

[0007] Hot air circulation flue-curing system with a heat recovery device, comprising a heating furnace, an air supply duct, a flue-curing barn, a return air duct, a heat recovery device, a return air bypass, a return air duct in front of the heating furnace, and a blower. Through the heat recovery device, while recovering waste heat, the moisture removal process is also completed. Energy-saving effects are achieved, the humidity of the hot air for baking tobacco is reduced, and the drying speed of the tobacco is accelerated. For the entire hot air circulation, first, the blower conveys the circulating hot air into the heating furnace for heating and temperature rise. Then, through the air supply duct, it is sent into the flue-curing barn in the form of air supply to bake the tobacco. After baking the tobacco, the hot air absorbs the moisture evaporated from the tobacco, increasing in humidity and decreasing in temperature; but it still carries a large amount of heat energy and leaves the flue-curing barn in the form of return air through the return air duct and is sent to the heat recovery device. After releasing the waste heat in the heat recovery device, the return air is discharged. The fresh air (fresh air, the same below) drawn from the atmospheric environment has low humidity and low temperature. It absorbs the waste heat released by the return air in the heat recovery device, is heated and then used as the circulating hot air, which is conveyed by the blower to the heating furnace to enter the next cycle of the hot air circulation.

[0008] For the said flue-curing barn, the internal space is the tobacco curing area. The circulating hot air for air supply enters from the front wall (the air inlet side wall, the same below), and after baking the tobacco, it flows out from the rear wall (the wall opposite to the air inlet, the same below) in the form of return air.

[0009] The circulating hot air for air supply enters from the front wall and the return air flows out from the rear wall, which enhances the flow of the circulating hot air in the flue-curing barn, reduces the dead corners of tobacco baking, avoids the situation of excessive humidity difference and temperature difference between different parts in the flue-curing barn, reduces the risk of the tobacco turning blue at the tips, and improves the quality of the flue-cured tobacco.

[0010] The said heat recovery device belongs to a shell-and-tube heat exchanger. Comparatively speaking, the fresh air drawn from the environment has low temperature and low humidity (low moisture content); while the return air from the flue-curing barn has high temperature and high humidity (high moisture content) and has waste heat. Through the heat recovery device, the fresh air absorbs the waste heat of the return air, and after the waste heat of the return air is released, it is discharged to the environment. At the same time, the heat recovery process and the moisture removal process are completed. These discharged return airs do not enter the hot air circulation again, and the fresh air after absorbing the waste heat enters the hot air circulation.

[0011] During the waste heat recovery process, the return air and the fresh air do not come into direct contact and exchange heat through the partition wall (heat transfer surface) of the heat recovery device, ensuring that the moisture content in the return air will not transfer to the fresh air. While achieving energy-saving effects, the purpose of moisture removal is also achieved. Therefore, in the flue-curing barn, the humidity of the circulating hot air is low, the drying speed of the tobacco is fast, and the tobacco curing cycle is shortened.

[0012] Due to the hot air circulation flue-curing system with a heat recovery device, the return air is directly discharged after waste heat recovery, and at the same time, the moisture removal process is realized. Therefore, the hot air circulation flue-curing system with a heat recovery device has a strong moisture removal function. The flue-curing barn does not need to be equipped with a skylight and a floor hole, and the problem of unorganized emission is also avoided.

[0013] For the air supply duct, an air supply gate is installed, and the air supply volume of the circulating hot air is adjusted by changing the opening degree of the air supply gate. The air supply temperature of the circulating hot air is increased by the heating furnace. The tobacco baking intensity in the tobacco baking room is jointly controlled by the air supply temperature and the air supply volume of the circulating hot air.

[0014] For the return air bypass, a return air bypass gate is arranged. According to the needs during the tobacco baking process, the functions of this gate are as follows: to close the high-humidity return air to prevent it from flowing back into the hot air circulation, especially during the moisture exhaust stage; to control part of the return air to flow back into the hot air circulation and utilize the high humidity of the return air to adjust the required humidity in the tobacco baking room. Increasing the return air volume flowing back, the humidity in the tobacco baking room rises.

[0015] This tobacco baking system enhances the flow of the circulating hot air in the tobacco baking room, improves the quality of the baked tobacco; while achieving energy-saving effects, it also achieves the purpose of moisture exhaust; the hot air in the tobacco baking room has low humidity, the drying speed of the tobacco is fast, shortening the tobacco baking cycle; it avoids the situation where the humidity difference and temperature difference between various parts in the tobacco baking room are too large, improving the quality of the baked tobacco.

[0016] Other advantages, objectives and features of the present invention will be reflected in the subsequent description. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the overall structure of the hot air circulation tobacco baking oven and system with a heat recovery device of the invention.

[0018] Figure 2 It is a schematic diagram of a partial structure of the hot air circulation tobacco baking oven and system with a heat recovery device of the invention.

[0019] Description of the Reference Numerals in the Drawings:

[0020] 1 - Heating furnace; 2 - Air supply duct; 3 - Tobacco baking room; 4 - Return air duct; 5 - Heat recovery device; 6 - Return air bypass; 7 - Return air duct in front of the heating furnace; 8 - Air supply fan; 11 - Heating pipe; 21 - Air supply gate; 31 - Tobacco baking area; 32 - Enclosure structure of the tobacco baking room; 33 - Front wall of the tobacco baking room; 34 - Rear wall of the tobacco baking room; 51 - Return air inlet gate of the heat recovery device; 52 - Return air inlet of the heat recovery device; 53 - Return air discharge port of the heat recovery device; 54 - Heat exchange surface of the heat recovery device; 55 - Fresh air inlet of the heat recovery device; 56 - Fresh air outlet of the heat recovery device; 57 - Fresh air outlet gate of the heat recovery device; 58 - Fresh air pipe; 61 - Return air bypass gate. Detailed Embodiments

[0021] The following will refer to the drawings to describe the preferred embodiments of the present invention in detail. The preferred embodiments only illustrate the present invention and do not limit the protection scope of the present invention.

[0022] Embodiment, seeFigure 1 and Figure 2 A hot air circulation flue-cured tobacco system with a heat recovery device, comprising a heating furnace 1, an air supply duct 2, a tobacco curing barn 3, a return air duct 4, a heat recovery device 5, a return air bypass 6, a return air duct in front of the heating furnace 7, and a fan 8. A fan 8 is arranged in the return air duct in front of the heating furnace 7, an air supply gate 21 is installed in the air supply duct 2, and a return air bypass gate 61 is arranged in the return air bypass 6. Through the heat recovery device 5, while recovering waste heat, the moisture removal process is also completed, reducing the humidity of the hot air for baking tobacco. An energy-saving effect is obtained, and the drying speed of tobacco is also accelerated.

[0023] Specifically, for the entire hot air circulation, first, the fan 8 transports the circulating hot air to the heating furnace 1, where it is heated and raised in temperature in the heating pipe 11. Then, through the air supply duct 2, it is sent into the tobacco curing barn 3 in the form of air supply to bake the tobacco in the tobacco curing area 31. After baking the tobacco, the circulating hot air leaves the tobacco curing barn 3 in the form of return air through the return air duct 4 and is sent to the heat recovery device 5. The return air releases waste heat in the heat recovery device 5 and then is discharged. The fresh air drawn from the atmospheric environment absorbs the waste heat released by the return air in the heat recovery device 5, is heated and raised in temperature, and then serves as circulating hot air, which is transported to the heating furnace through the fan 8 to enter the next cycle of the hot air circulation. In addition, by adjusting the opening degree of the return air bypass gate 61, an appropriate amount of return air volume is introduced to control the humidity in the tobacco curing area 31 of the tobacco curing barn 3. The suction of the fresh air and the introduction of this return air are both completed by the suction effect of the fan 8.

[0024] In this embodiment, the tobacco curing barn 3 is composed of a tobacco curing area 31 and a tobacco curing barn enclosure structure 32, where the tobacco curing barn enclosure structure 32 includes a front wall 33 and a rear wall 34 of the tobacco curing barn. The circulating hot air bakes the tobacco in the tobacco curing area 31.

[0025] The air supply of the hot air circulation enters from the front wall 33 of the tobacco curing barn, and the return air flows out from the rear wall 34 of the tobacco curing barn, enhancing the fluidity of the hot air circulation in the tobacco curing area 31, reducing the dead corners of tobacco baking, avoiding the situation of excessive humidity and temperature between various parts in the tobacco curing barn 3, reducing the risk of baking green tobacco tips, and improving the quality of flue-cured tobacco.

[0026] In this embodiment, the heat recovery device 5 includes a heat recovery device return air inlet gate 51, a heat recovery device return air inlet 52, a heat recovery device return air discharge port 53, a heat recovery device heat exchange surface 54, a heat recovery device fresh air inlet 55, a heat recovery device fresh air outlet 56, a heat recovery device fresh air outlet gate 57, and a fresh air pipe 58. Among them, a fresh air outlet gate 57 is arranged on the fresh air pipe 58. Both the waste heat recovery and the moisture removal process are realized through the heat recovery device 5.

[0027] The fresh air has a low temperature and low humidity, while the return air has a high temperature and high humidity. Through the return air inlet gate 51 of the heat recovery unit, the return air enters the heat recovery unit 5 from the return air inlet 52 of the heat recovery unit. The fresh air enters the heat recovery unit 5 from the fresh air inlet 55 of the heat recovery unit. The fresh air and the return air do not come into direct contact with each other, and heat is exchanged through the heat exchange surface 54 of the heat recovery unit. The return air transfers the waste heat to the fresh air. After releasing the waste heat, the return air is discharged from the return air discharge port 53 of the heat recovery unit. After being heated and warmed up, the fresh air flows out from the fresh air outlet 56 of the heat recovery unit, passes through the fresh air outlet gate 57 of the heat recovery unit and the fresh air pipe 58, and is sent to the return air pipe 7 in front of the heating furnace, entering the next hot air circulation.

[0028] In this embodiment, a supply air gate 21 is installed on the supply air pipe 2 to adjust the supply air volume of the circulating hot air. The supply air temperature of the circulating hot air is increased by using the heating furnace 1. The tobacco baking intensity in the tobacco baking room 3 is jointly controlled by the supply air temperature and supply air volume of the circulating hot air.

[0029] In this embodiment, a return air bypass 6 is provided with a return air bypass gate 61 to adjust the return air volume of the return air. Due to the high humidity of the return air, the humidity requirement in the tobacco baking room 3 is controlled by the amount of its return air volume. The greater the return air volume, the higher the humidity in the tobacco baking room 3.

[0030] This tobacco baking system enhances the flow of the circulating hot air in the tobacco baking room 3, improves the quality of the baked tobacco; while achieving energy-saving effects, it also achieves the purpose of moisture removal; the hot air humidity in the tobacco baking room 3 is low, the tobacco drying speed is fast, and the tobacco baking cycle is shortened.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that modifications or equivalent replacements can be made to the technical solutions of the present invention without departing from the spirit and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A hot air circulation flue-curing system with a heat recovery device, comprising a heating furnace (1), an air supply duct (2), a flue-curing barn (3), a return air duct (4), a heat recovery device (5), a return air bypass (6), a return air duct in front of the heating furnace (7), and a blower (8); characterized in that: A blower (8) is installed in the return air duct (7) in front of the heating furnace. An air supply gate (21) is installed in the air supply duct (2), and a return air bypass gate (61) is arranged in the return air bypass (6). Through the heat recovery device (5), while recovering waste heat, the dehumidification process is also completed, reducing the humidity of the hot air for baking tobacco, achieving an energy-saving effect and accelerating the drying speed of tobacco.

2. The hot air circulation flue-curing system with a heat recovery device according to claim 1, characterized in that: The tobacco baking room (3) consists of a tobacco baking area (31) and a tobacco baking room enclosure structure (32). The tobacco baking room enclosure structure (32) includes a front wall (33) and a rear wall (34) of the tobacco baking room. The circulating hot air bakes the tobacco in the tobacco baking area (31).

3. The hot air circulation flue-curing system with a heat recovery device according to claim 1, wherein: The supply air of the hot air circulation enters from the front wall (33) of the tobacco baking room, and the return air flows out from the rear wall (34) of the tobacco baking room, enhancing the fluidity of the hot air circulation in the tobacco baking area (31), reducing the dead corners of tobacco baking, avoiding the situation of excessive humidity and temperature differences between different parts of the tobacco baking room (3), reducing the risk of green tips on the baked tobacco, and improving the quality of the baked tobacco.

4. The hot air circulation flue-cured tobacco system with a heat recovery device according to claim 1, wherein: The heat recovery device (5) includes a heat recovery device return air inlet gate (51), a heat recovery device return air inlet (52), a heat recovery device return air discharge port (53), a heat recovery device heat exchange surface (54), a heat recovery device fresh air inlet (55), a heat recovery device fresh air outlet (56), a heat recovery device fresh air outlet gate (57), and a fresh air duct (58). Among them, a fresh air outlet gate (57) is installed in the fresh air duct (58). Both the waste heat recovery and the dehumidification process are realized through the heat recovery device (5).

5. The hot air circulation flue-curing system with a heat recovery device according to claim 1, characterized in that: An air supply gate (21) is installed in the air supply duct (2). The air supply volume of the circulating hot air is adjusted by the air supply gate (21). The supply air temperature of the circulating hot air is increased by using the heating furnace (1). The baking intensity of the tobacco in the tobacco baking room (3) is jointly controlled by the supply air temperature and the supply air volume of the circulating hot air.

6. The hot air circulation flue-curing system with a heat recovery device according to claim 1, wherein: A return air bypass gate (61) is arranged in the return air bypass (6). The return air volume of the return air is adjusted by the return air bypass gate (61). Due to the high humidity of the return air, the humidity requirement in the tobacco baking room (3) is controlled by the amount of its return air volume. The larger the return air volume, the higher the humidity in the tobacco baking room (3).

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