Oxygen-enhanced tobacco baking method and device for shortening yellowing period in high-altitude tobacco areas

Abstract

The present invention relates to a flue-cured tobacco oxygenation baking method and device for shortening the yellowing period of tobacco leaves in high-altitude tobacco areas. The method leads the outlet end of an oxygen tube that can pass oxygen to an air inlet in a dense curing room. In the early stage of yellowing of tobacco leaves during baking, oxygen is released at intervals to promote yellowing of tobacco leaves, shorten the yellowing period of tobacco leaves and the time of the entire baking process. The device includes a dense curing room, an oxygenation device and an oxygen tube. The outlet of the oxygenation device is connected to the oxygen tube. The oxygen tube penetrates into the dense curing room, and the outlet end thereof is led to the air inlet in the dense curing room to increase oxygen for the curing room in the early stage of yellowing of tobacco leaves. The method and device are not only conducive to shortening the yellowing period of tobacco leaves and the total baking time, but also easy to implement and simple to operate.

Description

Technical Field

[0001] The invention belongs to the technical field of primary processing of flue-cured tobacco leaves, and in particular relates to a flue-cured tobacco oxygen-enhancing baking method and a device for shortening the yellowing period of tobacco leaves in high-altitude areas. Background Art

[0002] With the advancement of science and technology and the development of modern agriculture, intensive flue-curing tobacco baking technology has been widely used in the field of tobacco leaf processing. Patent CN 108113040A discloses a method for baking tobacco leaves of the flue-cured tobacco variety Yunyan 87, which separates the lower tobacco leaves, middle tobacco leaves, and upper tobacco leaves in different flue-curing rooms for baking, slowly increases the temperature during the yellowing period of the tobacco leaves in the flue-curing room, and frequency-controlled the circulating fans used in the different baking stages of the yellowing period, the color fixing period, and the dry tendon period. The entire baking stage is divided into 10 small sections; at the same time, the temperature is raised at a low speed during the yellowing period, the temperature during the yellowing period is controlled at 39°C, the medium-high temperature yellowing temperature is extended for 12 hours, and the medium-late color fixing temperature is extended for 12 hours. Patent CN 111035039A discloses a baking process for tobacco leaves of a flue-cured tobacco variety KRK26, comprising: harvesting; raising the dry-bulb temperature to 34-35°C and the wet-bulb temperature to 33-34°C 4-6 hours after ignition, and baking; raising the dry-bulb temperature to 38-40°C and the wet-bulb temperature to 35-36°C, and baking; raising the dry-bulb temperature to 41-42°C and maintaining the wet-bulb temperature at 35-36°C, and baking; raising the dry-bulb temperature to 47-48°C and the wet-bulb temperature to 36-37°C, and baking; raising the dry-bulb temperature to 53-54°C and maintaining the wet-bulb temperature at 36-37°C, and baking; raising the dry-bulb temperature to 62-63°C and the wet-bulb temperature to 38-39°C, and baking; raising the dry-bulb temperature to 65-68°C and the wet-bulb temperature to 39-40°C, and baking. The "slow-in-the-first-mid-steady-in-the-last-fast low-temperature, low-humidity 7-step baking process" solves the three relationships between yellowing and withering, color fixation and baking aroma, and dry tendons and chromaticity of tobacco leaves. Patent CN 109691681 A discloses an intensive baking process for Yunyan 87 tobacco leaves to be soft and fragrant, which can reduce the proportion of green and mixed tobacco leaves and the proportion of smooth tobacco, so that the style characteristics and potential quality of Yunyan 87 varieties can be effectively expressed; including the following steps: tobacco leaf pretreatment; early yellowing period: dry bulb temperature 35-36℃, wet bulb temperature 34-35℃, stable temperature baking for 6-12h; middle yellowing period: dry bulb temperature 38-39℃, wet bulb temperature 36-37℃, stable temperature baking for 12-30h; late yellowing period: dry bulb temperature 41-42℃, wet bulb temperature 36-37℃, stable temperature baking for 12- 24h; early stage of color fixing: dry bulb temperature 43-44℃, wet bulb temperature 36-37℃, baking at steady temperature for 8-16h; middle stage of color fixing: dry bulb temperature 47-48℃, wet bulb temperature 37-38℃, baking at steady temperature for 20-30h; late stage of color fixing: dry bulb temperature 52-54℃, wet bulb temperature 38-39℃, baking at steady temperature for 12-24h; early stage of drying: dry bulb temperature 59-60℃, wet bulb temperature 39-40℃, baking at steady temperature for 4-6h; late stage of drying: dry bulb temperature 67-68℃, wet bulb temperature 40-42℃, baking at steady temperature for 24-36h.

[0003] Oxygen is one of the main raw materials for respiratory metabolism during the yellowing period of tobacco leaves. Its lack will lead to a decrease in the respiratory metabolism rate in the early stage of yellowing, thereby prolonging the yellowing period of tobacco leaves. In the publicly available intensive flue-curing tobacco baking technology, after the intensive flue-curing room is filled with tobacco leaves and the door is closed, the oxygen content in the flue-curing room is low for a period of time at the beginning of the yellowing period of tobacco leaves, resulting in slow respiratory metabolism of tobacco leaves and a longer yellowing period. In high-altitude areas, the oxygen content in the air is low, and the oxygen content in intensive flue-curing rooms is lower than that in low-altitude areas, resulting in a longer time required for the early stage of intensive yellowing of tobacco leaves in high-altitude areas. Summary of the invention

[0004] The object of the present invention is to provide a method and device for oxygen-enhanced tobacco baking that can shorten the yellowing period of tobacco leaves in high-altitude tobacco areas. The method and device are not only beneficial for shortening the yellowing period of tobacco leaves and the total baking time, but are also easy to implement and simple to operate.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for oxygen-enriched tobacco baking for shortening the yellowing period of tobacco leaves in high-altitude tobacco areas, wherein the outlet end of an oxygen tube that can pass oxygen is led to the air inlet in a dense baking room, and oxygen is released at intervals in the early stage of tobacco leaves turning yellow to promote the yellowing of tobacco leaves, thereby shortening the yellowing period of tobacco leaves and the time of the entire baking process.

[0006] Furthermore, the method specifically comprises the following steps:

[0007] (1) Early stage of oxygenation and yellowing: After the flue-curing room is filled with tobacco leaves, light a fire and raise the dry bulb temperature of the flue-curing room from room temperature to 36°C, and set the wet bulb temperature to 35°C; start releasing oxygen at intervals after the dry bulb temperature rises to 36°C, and keep the temperature stable for 10-14 hours until the tobacco leaves in the high temperature layer sweat and the length of the leaf tips turning yellow reaches more than 3 cm;

[0008] (2) Middle stage of yellowing: Increase the dry bulb temperature from 36°C to 38°C, set the wet bulb temperature to 35-36°C, and keep the temperature constant for 24-40 hours; until the tobacco leaves in the high temperature layer turn 70%-80% yellow, and the leaves collapse and become soft;

[0009] (3) Late yellowing stage: Raise the dry bulb temperature to 40-42°C, set the wet bulb temperature to 37-38°C, and keep the temperature constant for 24-36 hours until the tobacco leaves in the high temperature layer turn yellow by more than 90%, the main veins become soft, the yellow leaves turn blue, and oxygenation stops;

[0010] (4) Early color fixation: Raise the dry bulb temperature to 45-47°C and set the wet bulb temperature to 38-39°C. Keep the temperature constant for 24-36 hours until the tobacco leaves turn completely yellow, with yellow veins and curled edges.

[0011] (5) Late color fixation: Increase the dry bulb temperature to 54-55°C, set the wet bulb temperature to 39-40°C, and keep the temperature stable for 18-32 hours until the leaves are completely dry and rolled up;

[0012] (6) Drying period: Raise the dry-bulb temperature to 65-68°C and set the wet-bulb temperature to 41-42°C. Maintain the temperature for 35-40 hours until the main vein is completely dry.

[0013] Furthermore, in the step (1), oxygen is released starting from when the dry bulb temperature rises to 36°C, once every 2 hours, and each time for 5 minutes.

[0014] The present invention also provides a flue-cured tobacco oxygen-enriched baking device for shortening the yellowing period of tobacco leaves in high-altitude areas, comprising a dense baking room, an oxygen-enriched device and an oxygen pipe. The outlet of the oxygen-enriched device is connected to the oxygen pipe, which penetrates into the dense baking room, and the outlet end of the oxygen pipe is led to the air inlet in the dense baking room, so as to increase oxygen for the baking room in the early stage of yellowing of tobacco leaves.

[0015] Furthermore, the oxygen enrichment device comprises an oxygen cylinder filled with high-pressure oxygen and an oxygen pressure reducer, and the oxygen pressure reducer is connected to the oxygen cylinder and the oxygen tube respectively.

[0016] Furthermore, the outlet gas pressure of the oxygen pressure reducer is controlled to be 0.1 MPa.

[0017] Furthermore, the intensive baking room is provided with a cable through hole for passing the temperature and humidity sensor probe cable of the automatic controller. The oxygen pipe passes through the cable through hole into the smoke loading chamber, rises along the side wall of the heating chamber to the center of the air inlet of the baking room and is fixed to the smoke loading rack.

[0018] Furthermore, a temperature and humidity sensor probe is provided in the middle of the tobacco loading chamber to measure the temperature and humidity of the second layer of tobacco leaves.

[0019] Compared with the prior art, the present invention has the following beneficial effects: the method and device increase the oxygen content in the curing room and improve the respiratory metabolism rate of tobacco leaves by introducing oxygen in the early stage of tobacco leaves turning yellow, thereby effectively accelerating the yellowing speed of tobacco leaves, shortening the yellowing period of tobacco leaves and the total curing time, thereby reducing the power consumption and coal consumption of baking. In addition, the present invention has a simple structure, is easy to operate, and is easy to implement in existing intensive curing rooms. Therefore, the present invention has strong practicality and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the device structure of an embodiment of the present invention.

[0021] Figure 2 Schematic diagram of the oxygen pipe inlet on the intensive baking room in an embodiment of the present invention.

[0022] In the figure, 1-intensive baking room, 2-oxygen pipe, 3-oxygen cylinder, 4-oxygen pressure reducer, 101-air inlet, 102-cable through hole (oxygen pipe inlet), 103-heating chamber, 104-smoke loading chamber, 105-heater, 106-circulating fan, 107-circulating fan maintenance port, 108-automatic controller, 109-furnace door, 110-ash pit, 111-combustion port, 112-dehumidification window, 113-observation window, 114-temperature and humidity sensor probe located in the middle of the smoke loading chamber. DETAILED DESCRIPTION

[0023] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0024] After the tobacco leaves are loaded into the intensive drying room and begin to be dried, a large amount of oxygen is consumed during the respiratory metabolism of the tobacco leaves during the yellowing process. In the early stage of the yellowing of the tobacco leaves, the air inlet door of the drying room is basically not opened, and it is difficult for external oxygen to enter the drying room for replenishment, which delays the process of respiratory metabolism and the yellowing time is longer.

[0025] To address this problem, the present invention provides a flue-cured tobacco oxygen-enhanced baking method for shortening the yellowing period in high-altitude tobacco areas. The outlet end of an oxygen pipe that can pass oxygen is led to the air inlet in a dense baking room. In the early stage of tobacco leaf yellowing, oxygen is released at intervals to promote the yellowing of tobacco leaves, shorten the yellowing period of tobacco leaves and the entire baking process. The present invention is based on a three-stage baking method and specifically includes the following steps:

[0026] (1) Early stage of oxygenation and yellowing: After the flue-curing room is filled with tobacco leaves, light a fire and raise the dry bulb temperature of the flue-curing room from room temperature to 36°C within 5 hours. Set the wet bulb temperature to 35°C and keep the temperature stable for 10-14 hours. Start releasing oxygen from the time the dry bulb temperature rises to 36°C, once every 2 hours for 5 minutes each time, until the tobacco leaves in the high temperature layer sweat and the length of the leaf tips turning yellow reaches more than 3 cm;

[0027] (2) Middle stage of yellowing: Raise the dry bulb temperature from 36°C to 38°C within 4 hours, set the wet bulb temperature to 35-36°C, and keep the temperature constant for 24-40 hours; until the tobacco leaves in the high temperature layer turn 70%-80% yellow, and the leaves collapse and become soft;

[0028] (3) Late yellowing stage: Raise the dry bulb temperature to 40-42°C, set the wet bulb temperature to 37-38°C, and keep the temperature constant for 24-36 hours until the tobacco leaves in the high temperature layer turn yellow by more than 90%, the main veins become soft, the yellow leaves turn blue, and oxygenation stops;

[0029] (4) Early stage of color fixation (yellow leaves): Raise the dry bulb temperature to 45-47°C and set the wet bulb temperature to 38-39°C. Keep the temperature constant for 24-36 hours until the leaves are completely yellow, with yellow veins and curled edges.

[0030] (5) Late color fixation (drying): Raise the dry-bulb temperature to 54-55°C, set the wet-bulb temperature to 39-40°C, and keep the temperature constant for 18-32 hours until the leaves are completely dry and rolled up;

[0031] (6) Drying period: Raise the dry-bulb temperature to 65-68°C and set the wet-bulb temperature to 41-42°C. Maintain the temperature for 35-40 hours until the main vein is completely dry.

[0032] To implement the above method, Figure 1-2 As shown, the present invention also provides a flue-cured tobacco oxygen-enriched baking device for shortening the yellowing period of tobacco leaves in high-altitude areas, comprising a dense curing room 1, an oxygen-enriched device and an oxygen pipe 2, wherein the outlet of the oxygen-enriched device is connected to the oxygen pipe 2, the oxygen pipe penetrates into the dense curing room 1, and the outlet end thereof is led to the air inlet 101 in the dense curing room, so as to oxygenate the curing room in the early stage of yellowing of tobacco leaves.

[0033] In order to facilitate implementation in existing intensive baking barns, the present invention utilizes the cable through hole 102 opened on the intensive baking barn for passing the temperature and humidity sensor probe cable of the automatic controller. The oxygen pipe passes through the cable through hole into the smoke loading chamber, rises along the side wall of the heating chamber to the center of the air inlet of the baking barn and is fixed to the smoke loading rack.

[0034] In order to achieve accurate control of the baking process, a temperature and humidity sensor probe 114 is provided in the middle of the tobacco loading chamber 104 to measure the temperature and humidity in the middle of the two layers of tobacco leaves.

[0035] In this embodiment, the oxygen enrichment device includes an industrial oxygen cylinder 3 filled with high-pressure oxygen and an oxygen pressure reducer 4, and the oxygen pressure reducer 4 is connected to the oxygen cylinder and the oxygen pipe respectively.

[0036] When in use, first turn on the oxygen cylinder valve switch knob (the reading of the oxygen reducer's inlet pressure gauge is the oxygen cylinder's oxygen pressure, in MPa), then turn the oxygen reducer handle clockwise, and when you hear the sound of deflation, oxygen begins to be released. The reading of the oxygen reducer outlet pressure gauge is controlled to 0.1 MPa. The oxygen release interval is measured in time, consistent with the coal adding time, and is released every 2 hours. Each time it is released, the oxygen reducer outlet pressure is controlled to 0.1 MPa, and the release time is 5 minutes.

[0037] The amount of oxygen added in the intensive curing room of the present invention increases the oxygen content in the early stage of yellowing in the intensive curing room at an altitude of 2400m to the level of 0 altitude. One 40-liter oxygen tank is required for the lower leaves, 1.5 tanks are required for the middle leaves, and 2 tanks are required for the upper leaves.

[0038] In summary, the method and device of the present invention are simple and easy to implement. Civilian high-pressure industrial oxygen is used as the oxygen source for oxygen supplementation in intensive baking rooms, which is reliable and low in cost. The intensive baking room oxygen supplementation device composed of a high-pressure industrial oxygen cylinder, an oxygen pressure reducer, and an oxygen pipe is safe and reliable, easy to operate, simple to use, and has strong scalability.

[0039] In order to further verify the effect of the oxygen-enriched baking method provided by the present invention, the lower tobacco leaves of the flue-cured tobacco variety Yunyan 87 were selected, and the tobacco leaves were baked using the method of the present invention and the traditional tobacco leaf baking method (three-stage six-step baking method) as controls, and the difference in time required for the baking process was statistically compared.

[0040] The parameters of the control baking method and the yellowing and drying target states are as follows:

[0041] (1) Early yellowing stage: Heating rate 1℃ / h, dry bulb temperature rises to 36℃, wet bulb temperature 35℃, airflow descending curing room, temperature stabilized until the tip of the high temperature layer of tobacco leaves turns yellow more than 3cm. Maintain temperature for 10-14h.

[0042] (2) Middle stage of yellowing: Raise the temperature at 1°C / h to 38°C dry bulb temperature, 36°C wet bulb temperature, and maintain the temperature until the leaves become soft and 70% to 80% yellow. Maintain the temperature for 40-48h.

[0043] (3) Late yellowing stage: Raise the temperature at 0.5℃ / h to a dry bulb temperature of 42℃ and a wet bulb temperature of 38℃. Maintain the temperature until the leaves turn 90% to 100% yellow, the main veins become soft, the leaves collapse completely, and the yellow leaves have blue veins. Maintain the temperature for 33-41.5h.

[0044] (4) Early stage of color fixation: 0.5℃ / h to dry bulb temperature 48℃; wet bulb temperature: 38℃, stabilize the temperature until the tobacco leaves are completely yellow, the veins turn yellow or white, the tobacco leaves are about 1 / 2 dry, the leaves are yellow with yellow veins and curled edges. Maintain the temperature for 24-28 hours.

[0045] (5) Late color fixation: 0.5℃ / 1h to dry bulb temperature 54℃; wet bulb temperature: 40℃, keep the temperature steady until the leaves are completely dry, yellow with yellow veins and curled. The estimated baking time is 18-24h.

[0046] (6) Drying period: 1℃ / h to dry bulb temperature 65-68℃; wet bulb temperature: 42℃, keep the temperature steady until the leaves and main veins are completely dry. The estimated baking time is 35-40h.

[0047] According to the time consumption results of the two methods at the end of baking, compared with the traditional method, the total baking time of the method of the present invention can be effectively shortened by 8-25h.

[0048] The above are preferred embodiments of the present invention. Any changes made according to the technical solution of the present invention, as long as the resulting functions do not exceed the scope of the technical solution of the present invention, belong to the protection scope of the present invention.

Claims

1. A flue-cured tobacco oxygen-enhanced baking method for shortening the yellowing period of tobacco in high-altitude areas, characterized in that: Lead the outlet end of the oxygen pipe that can pass oxygen to the air inlet in the intensive curing room, and release oxygen at intervals in the early stage of tobacco leaves turning yellow during curing to promote the yellowing of tobacco leaves, shorten the yellowing period of tobacco leaves and the entire curing process; specifically, the following steps are included: (1) Early stage of oxygenation and yellowing: After the flue-curing room is filled with tobacco leaves, light a fire and raise the dry bulb temperature of the flue-curing room from room temperature to 36°C, and set the wet bulb temperature to 35°C; from the time the dry bulb temperature rises to 36°C, oxygen is released at intervals, once every 2 hours, for 5 minutes each time, and the temperature is kept stable for 10-14 hours, until the tobacco leaves in the high temperature layer sweat and the length of the leaf tips turning yellow reaches more than 3 cm; (2) Middle stage of yellowing: Increase the dry bulb temperature from 36°C to 38°C, set the wet bulb temperature to 35-36°C, and keep the temperature constant for 24-40 hours; until the tobacco leaves in the high temperature layer turn 70%-80% yellow, and the leaves collapse and become soft; (3) Late yellowing stage: the dry bulb temperature is raised to 40-42°C, the wet bulb temperature is set to 37-38°C, and the temperature is kept stable for 24-36 hours until the tobacco leaves in the high temperature layer turn yellow by more than 90%, the main veins become soft, the yellow leaves have blue veins, and oxygenation stops; (4) Early color fixation: Raise the dry bulb temperature to 45-47°C and set the wet bulb temperature to 38-39°C. Keep the temperature constant for 24-36 hours until the tobacco leaves are completely yellow, with yellow veins and curled edges. (5) Late color fixation: Increase the dry bulb temperature to 54-55°C, set the wet bulb temperature to 39-40°C, and keep the temperature stable for 18-32 hours until the leaves are completely dry and rolled up; (6) Drying period: Raise the dry-bulb temperature to 65-68°C and set the wet-bulb temperature to 41-42°C for 35-40 hours until the main vein is completely dry.

2. A flue-cured tobacco oxygen-enhanced baking device for shortening the yellowing period of tobacco in high-altitude areas for implementing the method as claimed in claim 1, characterized in that: It includes a dense curing room, an oxygen enrichment device and an oxygen pipe, wherein the outlet of the oxygen enrichment device is connected to the oxygen pipe, the oxygen pipe penetrates into the dense curing room, and the outlet end thereof is led to the air inlet in the dense curing room, so as to enrich the curing room with oxygen in the early stage of yellowing of tobacco leaves; The oxygen enrichment device comprises an oxygen cylinder filled with high-pressure oxygen and an oxygen reducer, wherein the oxygen reducer is connected to the oxygen cylinder and the oxygen pipe respectively; the outlet air pressure of the oxygen reducer is controlled to be 0.1 MPa; The intensive curing room is provided with a cable through hole for passing the temperature and humidity sensor probe cable of the automatic controller. The oxygen pipe passes through the cable through hole into the smoke loading chamber, rises along the side wall of the heating chamber to the center of the air inlet of the curing room and is fixed to the smoke loading rack; a temperature and humidity sensor probe is provided in the middle of the smoke loading chamber to measure the temperature and humidity of the second layer of tobacco leaves.

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