A flue-cured tobacco baking process based on biomass energy

Abstract

The invention discloses a flue-cured tobacco baking process based on biomass energy, which firstly maintains the same temperature and humidity before 35-36°C and in the early stage of 35-36°C stable temperature to promote yellowing of tobacco leaves to prevent tobacco leaves from being baked green; secondly, the heating rate of the dry bulb temperature between 48-60°C is reduced, and the dry bulb temperature and wet bulb temperature in the dry rib period are reduced to 1-2°C slightly lower than the conventional baking to prevent tobacco leaves from being baked red; finally, when the whole kang tobacco leaves are almost completely dried in the dry rib period, the dry bulb temperature is gradually reduced to 54°C in stages to prevent excessive moisture regeneration of tobacco leaves due to excessive cooling after the fire is stopped. Aiming at the problems existing in biomass energy baking, the method of the invention changes the baking process in a targeted manner, can improve the appearance quality of tobacco leaves after baking, and reduce the proportion of green tobacco leaves and red tobacco leaves.

Description

Technical Field

[0001] The invention relates to a flue-cured tobacco baking process based on biomass energy, belonging to the technical field of tobacco leaf baking. Background Art

[0002] Coal, as an energy source for flue-cured tobacco, emits pollutants such as sulfur dioxide, nitrogen oxides, carbon monoxide, carbon dioxide, and dust during curing, which has a certain negative impact on the ecological environment. With people's increasing attention to ecological environmental protection and the continuous development of science and technology, the development of flue-cured tobacco curing using biomass clean energy has become a current hot spot. Guizhou, as a major flue-cured tobacco-growing province in my country, currently has nearly 60,000 biomass curing houses, which exceeds 2 / 3 of the total number of curing houses in the province. Although biomass clean energy has the advantages of environmental protection, fast heating, and precise temperature and humidity control, production shows that the curing of biomass fuel energy is prone to the phenomenon of curing green tobacco and curing red tobacco. Therefore, improving the supporting curing process of biomass energy curing is an important guarantee for improving the quality of tobacco leaves.

[0003] The patent document (publication number: CN109820229A) discloses a biomass burner intensive baking precision baking process, including four baking stages: ignition stage, yellowing stage, color fixing stage and dry rib stage. One key temperature and humidity point is controlled in the ignition stage, three key temperature and humidity points are controlled in the yellowing stage, four key temperature and humidity points are controlled in the color fixing stage, and two key temperature and humidity points are controlled in the dry rib stage. The whole baking process adopts the tobacco temperature and humidity automatic control system. The temperature and humidity sensors are placed on the high-temperature platform of the intensive baking room, 2 meters away from the insulation wall and 1 meter away from the wall of the smoke chamber; the patent document The document (publication number: CN109288113A) discloses a baking process of Yunyan 87 in a biomass energy curing room, which is an improvement on the three-stage baking process of the prior art. According to the characteristics and quality of the tobacco leaves of the Yunyan 87 tobacco variety, the following steps are designed: tobacco weaving and loading on the kang - ignition and temperature control - tobacco leaf yellowing stage - tobacco leaf color setting stage - tobacco leaf dry tendon stage; the paper document (title: The influence of low-temperature and low-humidity baking process based on biomass pellet fuel on the quality of Yunyan 87 tobacco leaves) shows that the low-temperature and low-humidity yellowing baking process can improve the baking quality of Yunyan 87 tobacco leaves planted in the Xiangxi tobacco area. Although the above technical solution can improve the quality of tobacco leaves after baking, the problems of baking green and baking red tobacco leaves have not been effectively solved, so more complete and systematic tobacco leaf baking supporting technical measures are needed. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a baking process which can solve the problem of baking green tobacco and baking red tobacco with biomass energy, so as to overcome the shortcomings of the prior art.

[0005] The technical solution of the present invention is: a flue-cured tobacco baking process based on biomass energy comprises the following steps:

[0006] S1. After the biomass energy curing room is loaded with smoke, do not ignite, close the cold air inlet and moisture removal shutters, turn on the high speed of the circulating fan, and circulate internally for 2 to 3 hours;

[0007] S2. Start the ignition program, turn on the circulating fan at a low speed, raise the dry bulb temperature to 31-33°C at a heating rate of 1°C / h, and bake at a constant temperature for 6-10 hours at the same temperature and humidity until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow;

[0008] S3. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 35-36°C at a heating rate of 1°C / h, and bake at the same temperature and humidity for 4-6 hours; then lower the wet-bulb temperature to 34-35°C, bake at a steady temperature for 6-10 hours, until the high-temperature layer tobacco leaves turn 30% to 40% yellow and the leaves become slightly soft;

[0009] S4. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 38-39°C and the wet-bulb temperature to 35-37°C at a heating rate of 1°C / h, and bake at a steady temperature for 18-35h until the tobacco leaves in the high-temperature layer turn 80% yellow and become soft;

[0010] S5. Turn on the high speed of the circulating fan, raise the dry bulb temperature to 40-41°C and the wet bulb temperature to 36-37°C at a heating rate of 1°C / 1-2h, and bake at a steady temperature for 10-15h until the base of the high-temperature layer tobacco leaves is slightly green and the main veins are soft and withered;

[0011] S6. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 42-43°C and the wet bulb temperature to 36-37°C at a rate of 1°C / 2-3h, and bake at a steady temperature for 10-15h until the tobacco leaves in the high-temperature layer turn yellow and blue, become fully soft and withered, and the tobacco leaves in the middle layer turn 80% to 90% yellow and become soft;

[0012] S7. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 44-45°C and the wet bulb temperature to 36-37°C at a rate of 1°C / 2-3h, and bake at a steady temperature for 6-10h until the high-temperature layer tobacco leaves are hooked and curled;

[0013] S8. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 47-48℃ and the wet bulb temperature to 37-38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 15-25h until the main tendons of the high-temperature layer tobacco leaves turn white and the leaves are in a small roll state;

[0014] S9. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 50-51°C at a heating rate of 1°C / 2h, and the wet bulb temperature to 38°C, and bake at a steady temperature for 4-8h until the high-temperature layer of tobacco leaves is more than 2 / 3 dry;

[0015] S10. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 53-54°C at a heating rate of 1°C / 2h, and the wet bulb temperature to 39°C, and bake at a steady temperature for 15-25h until all the leaves on the kang are dry and the main tendons are 1 / 3 to 1 / 2 dry;

[0016] S11. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 60℃ at a heating rate of 1℃ / 2h, and the wet bulb temperature to 39-40℃, and bake at a steady temperature for 4-5h until the main tendons of the tobacco leaves are more than 1 / 2 dry;

[0017] S12. Start the circulating fan at a low speed, raise the dry-bulb temperature to 65-67°C and the wet-bulb temperature to 40-41°C at a heating rate of 1°C / h, and bake at a steady temperature for 15-20h until the tobacco leaves are almost completely dry;

[0018] S13. Keep the circulating fan at a low speed, reduce the dry bulb temperature to 60℃ and the wet bulb temperature to 39-40℃ at a rate of 1℃ / h, and bake at a steady temperature until the tobacco leaves are completely dry;

[0019] S14. Keep the circulating fan at low speed, reduce the dry bulb temperature to 54℃ and the wet bulb temperature to 38~39℃ at a rate of 1℃ / h, and stop the fire after the wet bulb is stable;

[0020] S15. Keep the circulating fan running at a low speed for 1 to 3 hours, then stop the circulating fan.

[0021] The aforementioned flue-cured tobacco baking process based on biomass energy is that in steps S1 to S15, the circulating fan on the temperature and humidity controller of the intensive baking room is set with two speed gears of low speed and high speed.

[0022] The aforementioned tobacco curing process based on biomass energy is that in steps S2 to S4 and S13 to S14, care should be taken to observe the biomass burner to avoid prolonged flameout resulting in a large difference between the actual dry-bulb temperature and the target dry-bulb temperature in the curing room, which would increase the curing loss.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The present invention firstly does not ignite after the dense curing room is loaded with tobacco, closes the cold air inlet and the dehumidification shutter, turns on the high-speed rotation of the circulating fan, and circulates internally for 2 to 3 hours; the dry-bulb temperature is 31 to 33°C, the temperature is the same and the humidity is the same, and the temperature is kept stable for 6 to 10 hours until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow; and the temperature is kept constant for 4 to 6 hours at 35 to 36°C and the humidity is the same, and the moisturizing baking is performed at a relatively low dry-bulb temperature to prevent the tobacco leaves from being baked green. Secondly, the heating rate is set to 1°C / 2h between the dry-bulb temperature of 48 to 60°C to slow down the heating rate to prevent the heating rate from being too fast, resulting in the tobacco leaves being baked red. Thirdly, the maximum dry-bulb temperature is set to 65 to 67°C, and the wet-bulb temperature is set to 40 to 41°C, which is slightly lower than the conventional baking by 1 to 2°C to prevent the tobacco leaves from being baked red under high temperature and high humidity conditions. Finally, when the tobacco leaves are almost completely dry during the drying period, the dry bulb temperature is gradually lowered to 54°C in stages to prevent excessive moisture recovery of the tobacco leaves after the fire is stopped, resulting in a reddish appearance. This method has the following benefits:

[0025] 1. It is beneficial to improve the appearance quality and grade structure of flue-cured tobacco leaves;

[0026] 2. It is helpful to reduce the proportion of blue smoke;

[0027] 3. It is helpful to reduce the proportion of flue-cured red tobacco.

[0028] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. DETAILED DESCRIPTION

[0029] The following will be combined with the tables in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1. The following steps are used in the flue-cured tobacco baking process based on biomass energy:

[0031] S1. After the biomass energy curing room is loaded with smoke, do not ignite, close the cold air inlet and moisture removal shutters, turn on the high speed of the circulating fan, and circulate internally for 2 hours;

[0032] S2. Start the ignition program, turn on the circulating fan at a low speed, raise the dry bulb temperature to 31°C at a heating rate of 1°C / h, and bake at a constant temperature for 10 hours at the same temperature and humidity until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow;

[0033] S3. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 35°C at a heating rate of 1°C / h, and bake at the same temperature and humidity for 6 hours; then lower the wet-bulb temperature to 34°C, bake at a constant temperature for 6 hours, until the high-temperature layer tobacco leaves turn 30% yellow and the leaves become slightly soft;

[0034] S4. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 38°C and the wet-bulb temperature to 35°C at a heating rate of 1°C / h, and bake at a steady temperature for 35 hours until the tobacco leaves in the high-temperature layer turn 80% yellow and become soft;

[0035] S5. Turn on the high speed of the circulating fan, raise the dry bulb temperature to 40℃ and the wet bulb temperature to 36℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 15h until the base of the high temperature layer tobacco leaves is slightly green and the main veins are soft and withered;

[0036] S6. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 42℃ and the wet bulb temperature to 36℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 15h until the tobacco leaves in the high temperature layer turn yellow and blue, become fully soft and withered, and the tobacco leaves in the middle layer turn 80% yellow and become soft;

[0037] S7. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 44°C and the wet bulb temperature to 36°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 10h until the high temperature layer tobacco leaves are hooked and curled;

[0038] S8. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 47°C and the wet bulb temperature to 37°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 20h until the main ribs of the high-temperature layer of tobacco leaves turn white and the leaves are in a small roll state;

[0039] S9. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 50℃ and the wet bulb temperature to 38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 8h until the high temperature layer tobacco leaves are more than 2 / 3 dry;

[0040] S10. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 53°C and the wet bulb temperature to 39°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 20h until all the tobacco leaves are dry and the main tendons are 1 / 3 to 1 / 2 dry;

[0041] S11. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 60℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 5h until the main tendons of the tobacco leaves are more than 1 / 2 dry;

[0042] S12. Start the circulating fan at a low speed, raise the dry-bulb temperature to 65°C and the wet-bulb temperature to 40°C at a heating rate of 1°C / h, and bake at a constant temperature for 20 hours until the tobacco leaves are almost completely dry;

[0043] S13. Keep the circulating fan at a low speed, reduce the dry bulb temperature to 60°C and the wet bulb temperature to 39°C at a rate of 1°C / h, and bake at a steady temperature until the tobacco leaves are completely dry;

[0044] S14. Keep the circulating fan at low speed, reduce the dry bulb temperature to 54℃ and the wet bulb temperature to 38℃ at a rate of 1℃ / h, and stop the fire after the wet bulb is stable;

[0045] S15. Keep the circulating fan running at low speed. After running for 2 hours, stop the circulating fan.

[0046] Example 2. The following steps are used in the flue-cured tobacco baking process based on biomass energy:

[0047] S1. After the biomass energy curing room is loaded with smoke, do not ignite, close the cold air inlet and moisture removal shutters, turn on the high speed of the circulating fan, and circulate internally for 3 hours;

[0048] S2. Start the ignition program, turn on the circulating fan at a low speed, raise the dry bulb temperature to 33°C at a heating rate of 1°C / h, and bake at a constant temperature for 6 hours at the same temperature and humidity until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow;

[0049] S3. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 36°C at a heating rate of 1°C / h, and bake at the same temperature and humidity for 4 hours; then lower the wet-bulb temperature to 35°C, bake at a constant temperature for 6 hours, until the high-temperature layer tobacco leaves turn 30% to 40% yellow and the leaves become slightly soft;

[0050] S4. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 39°C and the wet-bulb temperature to 37°C at a heating rate of 1°C / h, and bake at a steady temperature for 18 hours until the tobacco leaves in the high-temperature layer turn 80% yellow and become soft;

[0051] S5. Turn on the high speed of the circulating fan, raise the dry bulb temperature to 41°C and the wet bulb temperature to 37°C at a heating rate of 1°C / h, and bake at a constant temperature for 10 hours until the base of the high temperature layer tobacco leaves is slightly green and the main veins are soft and withered;

[0052] S6. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 43℃ and the wet bulb temperature to 36℃ at a heating rate of 1℃ / 3h, and bake at a steady temperature for 10h until the tobacco leaves in the high temperature layer turn yellow and blue, become fully soft and withered, and the tobacco leaves in the middle layer turn 80% to 90% yellow and become soft;

[0053] S7. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 44-45°C at a heating rate of 1°C / 3h, and the wet bulb temperature to 37°C, and bake at a steady temperature for 8h until the high-temperature layer tobacco leaves are hooked and curled;

[0054] S8. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 48℃ and the wet bulb temperature to 38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 15h until the main tendons of the high-temperature layer tobacco leaves turn white and the leaves are in a small roll state;

[0055] S9. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 51°C and the wet bulb temperature to 38°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 4h until the high temperature layer tobacco leaves are more than 2 / 3 dry;

[0056] S10. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 54°C and the wet bulb temperature to 39°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 15h until all the tobacco leaves are dry and the main tendons are 1 / 3 to 1 / 2 dry;

[0057] S11. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 4h until the main tendons of the tobacco leaves are more than 1 / 2 dry;

[0058] S12. Start the circulating fan at a low speed, raise the dry-bulb temperature to 67°C and the wet-bulb temperature to 41°C at a heating rate of 1°C / h, and bake at a constant temperature for 15 hours until the tobacco leaves are almost completely dry;

[0059] S13. Keep the circulating fan at a low speed, reduce the dry bulb temperature to 60℃ and the wet bulb temperature to 40℃ at a rate of 1℃ / h, and bake at a steady temperature until the tobacco leaves are completely dry;

[0060] S14. Keep the circulating fan at low speed, reduce the dry bulb temperature to 54℃ and the wet bulb temperature to 39℃ at a rate of 1℃ / h, and stop the fire after the wet bulb is stable;

[0061] S15. Keep the circulating fan running at a low speed for 1 to 3 hours, then stop the circulating fan.

[0062] Example 3. The following steps are used in the flue-cured tobacco baking process based on biomass energy:

[0063] S1. After the biomass energy curing room is loaded with smoke, do not ignite, close the cold air inlet and moisture removal shutters, turn on the high speed of the circulating fan, and circulate internally for 2.5 hours;

[0064] S2. Start the ignition program, turn on the circulating fan at a low speed, raise the dry bulb temperature to 32°C at a heating rate of 1°C / h, and bake at a constant temperature for 8 hours at the same temperature and humidity until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow;

[0065] S3. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 35.5℃ at a heating rate of 1℃ / h, and bake at the same temperature and humidity for 5 hours; then lower the wet-bulb temperature to 34.5℃, bake at a steady temperature for 8 hours, until the high-temperature layer tobacco leaves turn 30% to 40% yellow and the leaves become slightly soft;

[0066] S4. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 38.5℃ and the wet-bulb temperature to 36℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 27 hours until the tobacco leaves in the high-temperature layer turn 80% yellow and become soft;

[0067] S5. Turn on the high speed of the circulating fan, raise the dry bulb temperature to 40.5℃ and the wet bulb temperature to 36.5℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 10-15h until the base of the high temperature layer tobacco leaves is slightly green and the main veins are soft and withered;

[0068] S6. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 42-43°C and the wet bulb temperature to 36-37°C at a rate of 1°C / 2-3h, and bake at a steady temperature for 12.5h until the tobacco leaves in the high temperature layer turn yellow and blue, become fully soft and withered, and the tobacco leaves in the middle layer turn 80% to 90% yellow and become soft;

[0069] S7. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 44.5℃ and the wet bulb temperature to 36.5℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature for 8h until the high temperature layer tobacco leaves are hooked and curled;

[0070] S8. Maintain the high speed of the circulating fan, raise the dry-bulb temperature to 47.5℃ and the wet-bulb temperature to 37.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 20h until the main ribs of the high-temperature layer tobacco leaves turn white and the leaves are in a small roll state;

[0071] S9. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 50.5℃ and the wet bulb temperature to 38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 6h until the high temperature layer tobacco leaves are more than 2 / 3 dry;

[0072] S10. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 53.5℃ and the wet bulb temperature to 39℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 20h until all the tobacco leaves are dry and the main tendons are 1 / 3 to 1 / 2 dry;

[0073] S11. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 60℃ and the wet bulb temperature to 39.5℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 4.5h until the main tendons of the tobacco leaves are more than 1 / 2 dry;

[0074] S12. Start the circulating fan at a low speed, raise the dry-bulb temperature to 66°C and the wet-bulb temperature to 40.5°C at a heating rate of 1°C / h, and bake at a steady temperature for 17.5 hours until the tobacco leaves are almost completely dry;

[0075] S13. Keep the circulating fan at a low speed, reduce the dry-bulb temperature to 60°C and the wet-bulb temperature to 39.5°C at a rate of 1°C / h, and bake at a steady temperature until the tobacco leaves are completely dry;

[0076] S14. Keep the circulating fan at low speed, reduce the dry bulb temperature to 54℃ and the wet bulb temperature to 38.5℃ at a rate of 1℃ / h, and stop the fire after the wet bulb is stable;

[0077] S15. Keep the circulating fan running at low speed. After running for 2 hours, stop the circulating fan.

[0078] The method of the present invention is used to bake tobacco leaves. The experiment was carried out in tobacco-growing areas such as Weining County, Dafang County, and Fuquan City in Guizhou Province from 2019 to 2022. The test flue-cured tobacco variety was Yunyan 87, and the 12th to 13th leaf positions of the middle tobacco leaves were used as test materials.

[0079] As shown in Table 1-3, the applicant adopts a flue-cured tobacco baking process based on biomass energy and a conventional three-stage baking process using biomass for baking. It can be clearly seen that the flue-cured tobacco baking process based on biomass energy (the baking process of the present invention) can significantly improve the appearance quality and grade structure of the cured tobacco leaves and reduce the proportion of cured green tobacco and cured red tobacco. At the same time, after statistical analysis of tobacco leaf data from multiple regions, the data are as follows:

[0080] Table 1 Effects of different treatments on the appearance quality of flue-cured tobacco leaves

[0081]

[0082] Table 2 Effects of different treatments on the grade structure of flue-cured tobacco leaves

[0083]

[0084] Note: Different lowercase letters indicate significant differences among different treatments at the 5% level.

[0085] Table 3 Effects of different treatments on the ratio of flue-cured green tobacco and flue-cured red tobacco (%)

[0086]

[0087] The test data in the above table prove that the baking process of the present invention can: 1. improve the appearance quality and grade structure of the baked tobacco leaves; 2. reduce the proportion of green tobacco; 3. reduce the proportion of baked red tobacco. It has good practical value and applicability.

Claims

1. A flue-cured tobacco baking process based on biomass energy, characterized in that: The following steps are involved: S1. After the biomass energy curing room is loaded with smoke, do not ignite, close the cold air inlet and moisture removal shutters, turn on the high speed of the circulating fan, and circulate internally for 2~3 hours; S2. Start the ignition program, turn on the circulating fan at a low speed, raise the dry bulb temperature to 31-33°C at a heating rate of 1°C / h, and bake at a constant temperature for 6-10 hours at the same temperature and humidity until the tips and edges of the tobacco leaves in the high-temperature layer turn yellow; S3. Keep the circulating fan at a low speed, raise the dry-bulb temperature to 35-36℃ at a heating rate of 1℃ / h, and bake at the same temperature and humidity for 4-6 hours; then lower the wet-bulb temperature to 34-35℃, bake at a steady temperature for 6-10 hours, until the tobacco leaves in the high-temperature layer turn 30% to 40% yellow and become slightly soft; S4. Keep the circulating fan at a low speed, raise the dry bulb temperature to 38~39℃ and the wet bulb temperature to 35~37℃ at a heating rate of 1℃ / h, and bake at a steady temperature for 18~35h until the tobacco leaves in the high temperature layer turn 80% yellow and become soft; S5. Turn on the high speed of the circulating fan, raise the dry bulb temperature to 40-41°C and the wet bulb temperature to 36-37°C at a heating rate of 1°C / 1-2h, and bake at a steady temperature for 10-15h until the base of the high-temperature layer tobacco leaves is slightly green and the main veins are soft and withered; S6. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 42~43℃ and the wet bulb temperature to 36~37℃ at a heating rate of 1℃ / 2~3h, and bake at a steady temperature for 10~15h until the tobacco leaves in the high temperature layer turn yellow and blue, become fully soft and withered, and the tobacco leaves in the middle layer turn 80% to 90% yellow and become soft; S7. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 44-45°C and the wet bulb temperature to 36-37°C at a rate of 1°C / 2-3h, and bake at a steady temperature for 6-10h until the tobacco leaves in the high temperature layer are hooked and curled; S8. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 47~48℃ and the wet bulb temperature to 37~38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 15~25h until the main ribs of the high-temperature layer tobacco leaves turn white and the leaves are in a small roll state; S9. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 50~51℃ and the wet bulb temperature to 38℃ at a heating rate of 1℃ / 2h, and bake at a steady temperature for 4~8h until the tobacco leaves in the high temperature layer are more than 2 / 3 dry; S10. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 53-54°C and the wet bulb temperature to 39°C at a heating rate of 1°C / 2h, and bake at a steady temperature for 15-25h until all the leaves on the kang are dry and the main tendons are 1 / 3 to 1 / 2 dry; S11. Maintain the high speed of the circulating fan, raise the dry bulb temperature to 60℃ at a heating rate of 1℃ / 2h, and the wet bulb temperature to 39~40℃, and bake at a steady temperature for 4~5h until the main tendons of the tobacco leaves are more than 1 / 2 dry; S12. Start the circulating fan at a low speed, raise the dry-bulb temperature to 65-67°C and the wet-bulb temperature to 40-41°C at a heating rate of 1°C / h, and bake at a steady temperature for 15-20h until the tobacco leaves are almost completely dry; S13. Keep the circulating fan at a low speed, reduce the dry bulb temperature to 60℃ and the wet bulb temperature to 39~40℃ at a rate of 1℃ / h, and bake at a steady temperature until the tobacco leaves are completely dry; S14. Keep the circulating fan at low speed, reduce the dry bulb temperature to 54℃ and the wet bulb temperature to 38~39℃ at a rate of 1℃ / h, and stop the fire after the wet bulb stabilizes; S15. Keep the circulating fan running at a low speed for 1 to 3 hours, then stop the circulating fan.

2. The flue-cured tobacco baking process based on biomass energy according to claim 1, characterized in that: In steps S1 to S15, the circulating fan on the temperature and humidity controller of the intensive baking room is set with two speed gears of low speed and high speed.

3. The flue-cured tobacco baking process based on biomass energy according to claim 1, characterized in that: In steps S2 to S4 and S13 to S14, the biomass burner should be carefully observed to avoid long-term flameout, which may lead to a large difference between the actual dry-bulb temperature and the target dry-bulb temperature in the baking room, resulting in increased baking losses.

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