A method and system for tobacco leaf preparation

Abstract

Embodiments of the present application provide a method for preparing tobacco shreds, comprising: S1: adding tobacco shreds and expansion medium into an impregnation device respectively, so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds; S2: placing the impregnated tobacco shreds into an expansion device, and heating the impregnated tobacco shreds to obtain expanded tobacco shreds; S3: placing the expanded tobacco shreds into a heating device, and heat-treating the expanded tobacco shreds to volatilize the expansion medium remaining in the expanded tobacco shreds; and S4: placing the tobacco shreds obtained in step S3 into a moisture recovery device, and recovering moisture of the tobacco shreds to make the moisture content of the tobacco shreds meet production requirements. By heating the expanded tobacco shreds, the expansion medium remaining in the expanded tobacco shreds can be volatilized, so that the expansion medium in the tobacco shreds is effectively reduced, and the quality and safety of the cigarette products are improved. In addition, the present application also provides a system for preparing tobacco shreds.

Description

Technical Field

[0001] This invention relates to the field of tobacco processing technology, and in particular to a method and system for preparing tobacco shreds. Background Technology

[0002] Expanded tobacco is closely related to the quality of cigarettes. Expanded tobacco has strong filling capacity and good combustion performance. Adding expanded tobacco to cigarettes can reduce the amount of tobacco consumed per carton, reduce the amount of tar released from cigarettes, improve the chemical properties of cigarettes and smoke, and enhance the sensory quality of cigarettes.

[0003] Traditional expanded tobacco manufacturing typically utilizes carbon dioxide impregnation. The main process involves immersing the tobacco in liquid carbon dioxide in an impregnation tank for a specific time, allowing the liquid carbon dioxide to penetrate the tobacco cells. Then, the impregnation tank is depressurized, and the liquid and gaseous carbon dioxide are recovered. During this process, the liquid carbon dioxide inside the tobacco cools to atmospheric pressure, forming low-temperature dry ice. This dry ice tobacco is then subjected to high-temperature treatment, causing the dry ice inside the tobacco to rapidly sublimate and explosively escape from the tobacco cells, resulting in increased tobacco volume and thus producing expanded tobacco.

[0004] With the deepening research on tobacco expansion technology, equipment, and novel expansion media by researchers both domestically and internationally in recent years, a new expansion media, KC-2, has emerged. This media is composed of various organic chemical reagents. Tobacco shreds expanded with KC-2 exhibit a bright color and full shape, leading to KC-2 being considered a good tobacco expansion agent. However, as KC-2 has been gradually applied in actual production, researchers have discovered that although this media has good expansion performance, its small molecular weight and status as a fluorine-containing mixture mean that small amounts of these substances may remain in the tobacco shreds, posing a potential health hazard to cigarette consumers. Summary of the Invention

[0005] The purpose of this invention is to address the safety hazard posed by residual expansion media in current novel tobacco products. This invention provides a method and system for preparing tobacco that can significantly reduce the amount of expansion media within the tobacco, thereby providing technical assurance for the safety of using expansion media.

[0006] To make the technical solution and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0007] The present invention provides a method for preparing tobacco shreds, comprising the following steps:

[0008] Step S1: Add the tobacco shreds and the expansion medium into the impregnation equipment respectively, so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds;

[0009] Step S2: Place the impregnated tobacco into an expansion device and heat the impregnated tobacco to obtain expanded tobacco.

[0010] Step S3: Place the expanded tobacco into a heating device to heat-treat the expanded tobacco so that the expansion medium remaining in the expanded tobacco evaporates.

[0011] Step S4: Place the tobacco shreds obtained in step S3 into a rehumidification device to rehumidify the tobacco shreds so that the moisture content of the tobacco shreds meets the production requirements.

[0012] Optionally, in step S3, the heating device is provided with a vibrating conveying channel for conveying expanded tobacco shreds. The inner wall of the vibrating conveying channel is provided with multiple steam injection holes for injecting steam into the vibrating conveying channel to heat the expanded tobacco shreds passing through the vibrating conveying channel, thereby vaporizing the expansion medium remaining in the tobacco shreds.

[0013] Optionally, the steam injection hole located above the vibrating conveying channel is the first injection hole, and the steam injection holes located at the bottom and on the two side walls of the vibrating conveying channel are the second injection holes; the steam temperature ejected from the first injection hole is 120-135℃, and the steam pressure is 0.1-0.2 MPa; the steam temperature ejected from the second injection hole is 135-145℃, and the steam pressure is 0.3 MPa; the area where the steam injection holes are located is the heating zone, and the time for the expanded tobacco to pass through the heating zone is 8-10 seconds.

[0014] Optionally, a desiccant is provided at the outlet of the vibrating conveyor channel. The desiccant is located outside the heating zone and is used to remove the vaporized expansion medium and moisture.

[0015] Optionally, in step S4, the rehumidification device is provided with a humidification zone and a heating zone arranged sequentially along the tobacco conveying direction. The humidification zone uses a mixture of steam and water to spray and humidify the expanded tobacco, wherein the steam pressure is 0.4-0.5 MPa; the heating zone uses hot air to heat the expanded tobacco to raise its temperature, and the hot air can blow the expanded tobacco to the downstream area. The temperature of the hot air is 90°C, and the time for the expanded tobacco to pass through the heating zone is 120-130 seconds.

[0016] Optionally, in step S1, tobacco shreds with a moisture content of 17%-19% are placed into the sealed impregnation device, and gaseous and liquid atomized expansion medium is introduced into the impregnation device. The impregnation pressure is 5.7-6.5 bar, and the pressure is maintained for 10 minutes to allow the expansion medium to fully impregnate the tobacco shreds. After the pressure holding is completed, the liquid and gaseous expansion medium in the impregnation device are recovered.

[0017] Optionally, in step S2, the impregnated tobacco is heated using microwaves with a total microwave power of 54-55KW and a heating time of 3-4 minutes to expand the tobacco and obtain the expanded tobacco. Subsequently, the expansion medium in the expansion device is recovered.

[0018] Optionally, between step S2 and step S3, the following may also be included:

[0019] Loosening step: Loosen the expanded tobacco shreds obtained in step S2 using loosening equipment;

[0020] Storage steps: Store the loosened expanded tobacco in a storage device;

[0021] Feeding steps: The expanded tobacco shreds in the storage device are quantitatively and evenly fed into the heating device.

[0022] Optionally, after step S4, the tobacco is air-separated using an air separation device to remove stems and wet clumps from the tobacco.

[0023] The present invention also discloses a tobacco shred preparation system for implementing any of the aforementioned preparation methods. The tobacco shred preparation system includes:

[0024] Impregnation equipment is used to add tobacco shreds and an expansion medium so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds;

[0025] An expansion device is used to heat impregnated tobacco shreds to produce expanded tobacco shreds;

[0026] Heating equipment is used to heat-treat expanded tobacco shreds to cause the expansion medium remaining in the expanded tobacco shreds to volatilize;

[0027] A rehumidification device is used to rehumidify tobacco shreds produced by heating equipment, so that the moisture content of the tobacco shreds meets production requirements.

[0028] Optionally, the heating device includes:

[0029] The main body is provided with a vibrating conveying trough that runs through both ends of the main body, and a second injection hole is provided on the bottom and two side walls of the vibrating conveying trough;

[0030] A cover plate covers the vibrating conveying trough. The cover plate and the vibrating conveying trough together form a vibrating conveying channel, which is used to convey expanded tobacco. The inner wall of the cover plate is provided with a first injection hole.

[0031] Both the first and second injection holes are used to inject steam to heat the expanded tobacco shreds passing through the vibrating conveyor channel; the outlet of the vibrating conveyor channel is provided with a dehumidification port, which is used to remove the vaporized expansion medium and moisture.

[0032] Optionally, the rehumidification device is a drum with an inlet and an outlet. The inlet is equipped with an aerosol spraying mechanism for spraying steam and water onto the tobacco entering the drum. The drum is equipped with a hot air blowing mechanism with an air outlet for blowing hot air into the drum to heat up the tobacco inside. The hot air can also blow the tobacco in the drum toward the outlet. The air outlet is equipped with a regulating valve with an adjustable opening to regulate the flow rate of the hot air.

[0033] Optionally, along the conveying direction of the tobacco, the expansion device and the heating device may also include:

[0034] Loosening equipment is used to loosen expanded tobacco shreds produced by expansion equipment;

[0035] Storage equipment for storing loosened, expanded tobacco shreds;

[0036] Feeding equipment is used to quantitatively and evenly feed expanded tobacco from storage equipment into heating equipment.

[0037] Optionally, a wind classifier is also provided downstream of the rehumidification equipment. The wind classifier is used to classify the tobacco shreds produced by the rehumidification equipment to remove stems and wet clumps from the tobacco shreds.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The embodiments of the present invention utilize a heating device to heat-treat expanded tobacco shreds, causing the expansion medium remaining in the expanded tobacco shreds to volatilize, thereby effectively reducing the amount of expansion medium in the tobacco shreds and providing technical assurance for the safety of using expansion medium. Furthermore, by rehydrating the tobacco shreds obtained from the heating device, the moisture content of the tobacco shreds can be ensured to meet production requirements, improving the quality of the tobacco shreds. Attached Figure Description

[0040] Figure 1 This diagram shows a flowchart of a method for preparing tobacco shreds according to an embodiment of the present invention;

[0041] Figure 2 This diagram shows a structural block diagram of a tobacco preparation system according to an embodiment of the present invention.

[0042] Figure 3 This diagram illustrates a structural block diagram of a tobacco preparation system according to another embodiment of the present invention.

[0043] Figure 4 A schematic diagram of a heating device provided in an embodiment of the present invention is shown.

[0044] Figure label:

[0045] 1. Main body, 11. Vibrating conveyor trough, 2. Cover plate, 3. Dehumidification hood, 4. Heating area. Detailed Implementation

[0046] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0047] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0049] In the description of this embodiment, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0050] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0051] To make the technical solution and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0052] refer to Figure 1 The present invention provides a method for preparing tobacco shreds, comprising the following steps:

[0053] Step S1: Add the tobacco shreds and the expansion medium into the impregnation equipment respectively, so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds;

[0054] Step S2: Place the impregnated tobacco into an expansion device and heat the impregnated tobacco to obtain expanded tobacco.

[0055] Step S3: Place the expanded tobacco into a heating device to heat-treat the expanded tobacco so that the expansion medium remaining in the expanded tobacco evaporates.

[0056] Step S4: Place the tobacco shreds obtained in step S3 into a rehumidification device to rehumidify the tobacco shreds so that the moisture content of the tobacco shreds meets the production requirements.

[0057] The embodiments of the present invention utilize a heating device to heat-treat expanded tobacco shreds, causing the expansion medium remaining in the expanded tobacco shreds to volatilize, thereby effectively reducing the amount of expansion medium in the tobacco shreds and providing technical assurance for the safety of using expansion medium. Furthermore, by rehydrating the tobacco shreds obtained from the heating device, the moisture content of the tobacco shreds can be ensured to meet production requirements, improving the quality of the tobacco shreds.

[0058] Optionally, in step S3, the heating equipment includes a vibrating conveying channel for conveying expanded tobacco shreds. The inner wall of the vibrating conveying channel has multiple steam injection holes for injecting steam into the channel to heat the expanded tobacco shreds, thereby vaporizing the expansion medium remaining in the tobacco shreds. This embodiment utilizes steam to heat the expanded tobacco shreds, ensuring uniform heating and facilitating the volatilization of the expansion medium. Furthermore, steam heating can increase the moisture content of the expanded tobacco shreds, improving their processing resistance and expansion effect.

[0059] The steam injection hole located above the vibrating conveyor channel is the first injection hole, and the steam injection holes located at the bottom and on both side walls of the vibrating conveyor channel are the second injection holes. Preferably, the steam temperature ejected from the first injection hole is 120-135℃, and the steam pressure is 0.1-0.2 MPa; the steam temperature ejected from the second injection hole is 135-145℃, and the steam pressure is 0.3 MPa. The area where the steam injection holes are located is the heating zone 4, and the time for the expanded tobacco to pass through the heating zone 4 is 8-10 seconds. When the expanded tobacco enters the vibrating conveyor channel, the vibrating conveyor channel will vibrate and convey the expanded tobacco, causing the expanded tobacco to move along... Figure 4 The tobacco operates in the X direction as shown; during this process, the first and second injection holes inject steam into the expanded tobacco from different angles, ensuring full contact between the expanded tobacco and the steam, and promoting rapid evaporation of the expansion medium. After the expanded tobacco passes through the vibrating conveyor channel, its moisture content increases by 3%-5%.

[0060] Optionally, a desiccant is provided at the outlet of the vibrating conveyor channel. The desiccant is located outside the heating zone 4 and is used to drain the vaporized expansion medium and moisture to prevent the vaporized expansion medium from flowing back into the vibrating conveyor channel or polluting the environment.

[0061] Optionally, in step S4, the rehumidification equipment is provided with a humidification zone and a heating zone arranged sequentially along the tobacco conveying direction. After the tobacco enters the rehumidification equipment, it will pass through the humidification zone and the heating zone in sequence. The humidification zone uses a mixture of steam and water to spray and humidify the expanded tobacco, with a steam pressure of 0.4-0.5 MPa. The heating zone uses hot air to heat the expanded tobacco, raising its temperature to 90°C. The expanded tobacco spends 120-130 seconds passing through the heating zone. Specifically, this embodiment heats the air to generate hot air. The hot air increases the temperature of the expanded tobacco, further causing the expansion medium within the tobacco to volatilize. The vaporized expansion medium is quickly carried away by the hot air, reducing its residue. Additionally, the hot air blows the tobacco to the downstream area of ​​the rehumidification equipment, providing a certain degree of transport and dispersing the tobacco during transport, promoting loosening and preventing clumping. Furthermore, adjusting the hot air flow rate can regulate the moisture content of the tobacco to meet production requirements. Specifically, when the moisture content of the tobacco is low, the control system can reduce the hot air flow rate to increase the moisture content; conversely, when the moisture content is high, the control system can increase the hot air flow rate to decrease the moisture content. After processing in the rehumidification equipment, the moisture content of the tobacco can increase by 2%-4%.

[0062] Optionally, in step S1, tobacco shreds with a moisture content of 17%-19% are placed into a sealed impregnation device, and gaseous and liquid atomized expansion media are introduced into the impregnation device. The impregnation pressure is 5.7-6.5 bar, and the pressure is maintained for 10 minutes to allow the expansion media to fully impregnate the tobacco shreds. After the pressure holding period, the liquid and gaseous expansion media in the impregnation device are recovered. Specifically, the expansion media is KC-2.

[0063] Optionally, in step S2, the impregnated tobacco is heated using microwaves with a total microwave power of 54-55KW and a heating time of 3-4 minutes to expand the tobacco and obtain expanded tobacco. The expansion medium in the expansion device is then recovered.

[0064] Optionally, between step S2 and step S3, the following may also be included:

[0065] Loosening step: Loosen the expanded tobacco shreds obtained in step S2 using a loosening device; for example, the loosening device can be a loosening roller;

[0066] Storage steps: The loosened expanded tobacco is stored in a storage device to buffer the transport of the expanded tobacco.

[0067] Feeding steps: The expanded tobacco shreds in the storage device are quantitatively and evenly fed into the heating device, so that the expanded tobacco shreds can be heated evenly in the heating device.

[0068] Optionally, after step S4, the tobacco shreds are air-separated using an air-separation device to remove stems and wet clumps, ensuring the quality of the tobacco shreds.

[0069] refer to Figure 2 The present invention also discloses a tobacco shred preparation system for implementing any of the aforementioned preparation methods. Along the tobacco shred conveying direction, the tobacco shred preparation system comprises, in sequence:

[0070] Impregnation equipment is used to add tobacco shreds and an expansion medium so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds;

[0071] An expansion device is used to heat impregnated tobacco shreds to produce expanded tobacco shreds;

[0072] Heating equipment is used to heat-treat expanded tobacco shreds to cause the expansion medium remaining in the expanded tobacco shreds to volatilize;

[0073] A rehumidification device is used to rehumidify tobacco shreds produced by heating equipment, so that the moisture content of the tobacco shreds meets production requirements.

[0074] Specifically, in practical applications, conveying devices can be added between the above-mentioned equipment according to the specific site conditions to achieve automated conveying.

[0075] Optionally, refer to Figure 4 The heating equipment includes:

[0076] The main body 1 is provided with a vibrating conveying trough 11 that runs through the front and rear ends of the main body 1. The bottom and two side walls of the vibrating conveying trough 11 are provided with second injection holes.

[0077] Cover plate 2 covers the vibrating conveying trough 11. Cover plate 2 and vibrating conveying trough 11 together form a vibrating conveying channel. The vibrating conveying channel is used to convey expanded tobacco. The inner wall of cover plate 2 is provided with a first injection hole.

[0078] The area where the first and second injection holes are located is the heating zone 4. Both the first and second injection holes are used to inject steam to heat the expanded tobacco shreds passing through the vibrating conveying channel. A dehumidification hood 3 is provided outside the outlet of the vibrating conveying channel. The dehumidification hood 3 is provided with a dehumidification port, which is used to remove the vaporized expansion medium and moisture.

[0079] Optionally, the rehumidification device is a drum with an inlet and an outlet. An aerosol spraying mechanism is installed at the inlet to spray steam and water onto the tobacco entering the drum. The area covered by the steam and water sprayed by the aerosol spraying mechanism is the humidification zone. Inside the drum, a hot air blowing mechanism is installed with an air outlet to blow hot air into the drum. The area covered by the hot air is the heating zone. The hot air not only heats the tobacco inside the drum, further vaporizing the residual expansion medium, but also blows the tobacco towards the outlet, dispersing it and preventing clumping. A regulating valve is installed at the outlet to adjust the flow rate of the hot air, thereby controlling the moisture content of the tobacco. A dehumidification system is installed at the outlet to remove the gaseous expansion medium from the hot air.

[0080] Optionally, refer to Figure 3 Along the direction of tobacco conveying, the expansion device and the heating device also include:

[0081] Loosening equipment is used to loosen expanded tobacco shreds produced by expansion equipment;

[0082] Storage equipment for storing loosened, expanded tobacco shreds;

[0083] Feeding equipment is used to quantitatively and evenly feed expanded tobacco from storage equipment into heating equipment.

[0084] Optionally, a wind classifier is also provided downstream of the rehumidification equipment. The wind classifier is used to classify the tobacco shreds produced by the rehumidification equipment to remove stems and wet clumps from the tobacco shreds.

[0085] Table 1. Record of Detection of Expansion Medium Content in Tobacco Shreds

[0086] Serial Number Sampling points Average content of expansion medium (mg / kg) 1 expansion equipment discharge port 1346.96 2 Heating equipment discharge port 223.31 3 Rehumidification equipment discharge port 3.62

[0087] To detect the content of the expansion medium in the tobacco shreds prepared by the method of the present invention, the operator took samples of tobacco shreds from the outlets of the expansion equipment, heating equipment, and rehumidification equipment, and tested the content of the expansion medium in each sample. The test results are shown in Table 1 above. Specifically, to improve the accuracy of the test results, the operator took three samples at each sampling point, taking two samples simultaneously each time, with a 5-minute interval between adjacent samplings. The mass of each sample was 200g. The average content of the expansion medium in Table 1 is the average content of the expansion medium contained in six samples taken from the same sampling point. As can be seen from Table 1, after heat treatment in the heating equipment, the residual expansion medium in the tobacco shreds decreased from 1346.96mg / kg to 223.31mg / kg; after hot air treatment in the rehumidification equipment, the residual expansion medium in the tobacco shreds decreased from 223.31mg / kg to 3.62mg / kg. It can be seen that the preparation method provided by the present invention can effectively reduce the content of the expansion medium in tobacco shreds.

[0088] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A method for preparing tobacco shreds, characterized in that, Includes the following steps: Step S1: Add tobacco shreds and expansion medium to the impregnation equipment respectively, so that the tobacco shreds are impregnated in the expansion medium to form impregnated tobacco shreds; The expansion medium is KC-2; Step S2: Place the impregnated tobacco into an expansion device and heat the impregnated tobacco to obtain expanded tobacco. Step S3: The expanded tobacco is placed in a heating device for heat treatment to evaporate the expansion medium remaining in the tobacco. The heating device has a vibrating conveyor channel for conveying the expanded tobacco. Multiple steam injection holes are provided on the inner wall of the vibrating conveyor channel to inject steam into the channel, heating the expanded tobacco and vaporizing the remaining expansion medium. The steam injection hole at the top of the vibrating conveyor channel is the first injection hole, and the steam injection holes at the bottom and on the two side walls of the channel are the second injection holes. The steam temperature from the first injection hole is 120-135℃, and the steam pressure is 0.1-0.2 MPa. The steam temperature from the second injection hole is 135-145℃, and the steam pressure is 0.3 MPa. The area where the steam injection holes are located is the heating zone, and the expanded tobacco takes 8-10 seconds to pass through the heating zone. Step S4: Place the tobacco shreds obtained in step S3 into a rehumidification device to rehumidify them, ensuring the moisture content meets production requirements. The rehumidification device includes a humidification zone and a heating zone arranged sequentially along the tobacco shred conveying direction. The humidification zone uses steam and water to spray and humidify the expanded tobacco shreds, with a steam pressure of 0.4-0.5 MPa. The heating zone uses hot air to heat the expanded tobacco shreds, raising their temperature and allowing them to be blown downstream. The hot air temperature is 90°C, and the expanded tobacco shreds pass through the heating zone for 120-130 seconds.

2. The method for preparing tobacco shreds as described in claim 1, characterized in that, The outlet of the vibrating conveying channel is provided with a dehumidification port, which is located outside the heating area. The dehumidification port is used to drain the vaporized expansion medium and moisture.

3. The method for preparing tobacco shreds as described in claim 1, characterized in that, In step S1, tobacco shreds with a moisture content of 17%-19% are placed into the sealed impregnation device, and gaseous and liquid atomized expansion medium is introduced into the impregnation device. The impregnation pressure is 5.7-6.5 bar and the pressure is maintained for 10 minutes to allow the expansion medium to fully impregnate the tobacco shreds. After the pressure holding is completed, the liquid and gaseous expansion medium in the impregnation device are recovered.

4. The method for preparing tobacco shreds as described in claim 1, characterized in that, In step S2, the impregnated tobacco is heated using microwaves with a total microwave power of 54-55KW and a heating time of 3-4 minutes to expand the tobacco and obtain expanded tobacco. The expansion medium in the expansion device is then recovered.

5. The method for preparing tobacco shreds as described in claim 1, characterized in that, Between step S2 and step S3, the following is also included: Loosening step: Loosen the expanded tobacco shreds obtained in step S2 using loosening equipment; Storage step: Store the loosened expanded tobacco shreds in a storage device; Feeding step: The expanded tobacco shreds in the storage device are quantitatively and evenly fed into the heating device.

6. The method for preparing tobacco shreds according to any one of claims 1 to 5, characterized in that, After step S4, the tobacco shreds are air-separated using an air separation device to remove stems and wet clumps from the tobacco shreds.

7. A tobacco shred preparation system, characterized in that, For implementing the tobacco shred preparation method according to any one of claims 1 to 6, the tobacco shred preparation system comprises: Impregnation equipment is used to add tobacco shreds and an expansion medium to impregnate the tobacco shreds in the expansion medium to form impregnated tobacco shreds; An expansion device is used to heat the impregnated tobacco shreds to obtain expanded tobacco shreds; A heating device is used to heat treat the expanded tobacco shreds to cause the expansion medium remaining in the expanded tobacco shreds to volatilize; A rehumidification device is used to rehumidify the tobacco shreds produced by the heating device so that the moisture content of the tobacco shreds meets the production requirements. The heating device includes: The main body is provided with a vibrating conveying groove that runs through both ends of the main body, and the bottom and two side walls of the vibrating conveying groove are provided with second injection holes; A cover plate covers the vibrating conveying trough, and the cover plate and the vibrating conveying trough together form a vibrating conveying channel for conveying the expanded tobacco shreds. The inner wall of the cover plate is provided with a first injection hole. Both the first injection hole and the second injection hole are used to inject steam to heat the expanded tobacco shreds passing through the vibrating conveying channel; the outlet of the vibrating conveying channel is provided with a dehumidification port, which is used to remove the vaporized expansion medium and moisture. The rehumidification device is a drum with an inlet and an outlet. An aerosol spraying mechanism is installed at the inlet to spray steam and water onto the tobacco entering the drum. A hot air blowing mechanism is installed inside the drum, with an outlet for blowing hot air into the drum to heat the tobacco inside. The hot air also blows the tobacco towards the outlet. A regulating valve is installed at the outlet to adjust the flow rate of the hot air.

8. The tobacco shred preparation system as described in claim 7, characterized in that, Along the conveying direction of the tobacco, the expansion device and the heating device further include: A loosening device for loosening the expanded tobacco shreds obtained by the expansion device; Storage device for storing the loosened expanded tobacco shreds; A feeding device is used to quantitatively and evenly feed the expanded tobacco shreds in the storage device into the heating device.

9. The tobacco shred preparation system as described in claim 8, characterized in that, Downstream of the rehumidification equipment is an air separation device, which is used to air separate the tobacco shreds produced by the rehumidification equipment to remove stems and wet clumps from the tobacco shreds.

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