A characterization method for the processing intensity of a threshing and redrying roaster

Abstract

The present invention discloses a method for characterizing the processing intensity of a threshing and redrying baking machine, which is analyzed based on two main objects in the heat and mass transfer process during threshing and redrying baking, namely the leaves and the hot air. The components with low boiling points and easy volatility in the leaves are transferred to the hot air along with the volatilization of water in the leaves during baking. The volatilization amount of the components with low boiling points in the leaves is characterized by the volatilization amount of water in the leaves. At the same time, the moisture saturation degree of the hot air, that is, the moisture content, is used to control the speed of moisture mass transfer. The processing intensity of the threshing and redrying baking machine is characterized from two aspects: the total amount and speed of mass transfer between the leaves and the hot air during the threshing and redrying baking process. The present invention uses a quantitative method to characterize the processing intensity during the threshing and redrying baking process, and selects different leaf baking intensities according to the processing quality requirements of different types of tobacco leaf raw materials, effectively guiding the threshing and redrying processing technology.

Description

Technical Field

[0001] The present invention relates to the field of tobacco leaf processing, and specifically to a method for characterizing the processing intensity of a threshing and redrying baking machine. Background Art

[0002] In the tobacco industry, threshing and redrying is an important link in cigarette production, which is a process of processing tobacco bales of different grades into qualified cut tobacco. The threshing and redrying process mainly includes three stages: leaf conditioning, threshing and pneumatic separation, and leaf baking. And leaf baking is the only drying and dehydration process in the threshing and redrying process, and is the most important process affecting the processing intensity of threshing and redrying.

[0003] Leaf redrying is a key process in threshing and redrying. The purpose is to reduce the moisture content of the leaves, improve the processing performance of the leaves, and improve and enhance the sensory quality of the leaves. The drying process is a key process in the processing of leaves and cigarettes. At present, the commonly used drying methods in the tobacco industry include thin plate drying, pneumatic drying, carbon dioxide expansion drying, and leaf baking. The setting of drying process parameters directly affects the physical quality and sensory quality of the dried leaves and cut tobacco, and has a particularly obvious impact on the aroma characteristics and sensory quality of the leaves and cigarettes compared with other threshing and silk-making processes. The setting of the key parameters of the drying process is ostensibly the change of the temperature and moisture content of the material during the drying process, but essentially, significant changes have occurred in the physical quality, chemical composition, aroma components of the tobacco leaves, and sensory quality indicators such as the aroma quality, foreign odor, and irritation of the tobacco leaves. Leaf baking is a drying process in the threshing and redrying production process, which has the characteristics of long drying time, large water removal, and relatively small breakage due to the static state of the leaves. It mainly uses the fact that during the baking process of the leaves, under the action of the hot air temperature, the volatile small molecule components in the leaves are discharged with the exhaust hot air, thereby removing the foreign odor in the leaves, improving the aroma texture, and at the same time can partially promote the transformation of macromolecular substances in the leaves.

[0004] At present, the thin plate drying method is commonly used in the drying process of the tobacco industry, and key parameter combinations such as cylinder wall temperature, hot air temperature, hot air flow rate, residence time of cut tobacco, and filling coefficient of cut tobacco in the drum are used as the characterization indexes of cut tobacco processing intensity parameters to analyze the effects of various process parameters on indexes such as the sensory quality, aroma components and chemical composition, and physical quality of cut tobacco.

[0005] The patent with the title "A method for evaluating the consistency of the processing intensity of cut tobacco during the drum drying process based on the temperature rise process of cut tobacco" (Publication No. CN110286198A) dynamically detects the surface temperature of the cut tobacco in the drum, obtains the surface temperature distribution curve of the cut tobacco in the drum, and combines indicators such as the inlet temperature of the cut tobacco, the outlet temperature, and the moisture content of the cut tobacco at the outlet. By calculation, a combined index is obtained to characterize the processing intensity of the cut tobacco between batches during the thin plate drying process. This method requires dynamically detecting the surface temperature distribution of the cut tobacco in the drum during the thin plate drying process. During the thin plate drying process, the temperature probe is in instantaneous contact with the cut tobacco, and the temperature probe has thermal inertia, which has a certain impact on the accuracy of the temperature detection result.

[0006] The patent with the title "A method for accurately characterizing the processing intensity of materials in the cut tobacco drying process of cigarettes" (Publication No. CN103234936A) uses the near-infrared spectrum comparison analysis of the cut tobacco before and after drying, applies the principal component-Mahalanobis distance method, and uses the between-class average value of the Mahalanobis distance to characterize the processing intensity during the drying process. This method is complex to operate.

[0007] Technicians in the tobacco industry have also explored methods to characterize the processing intensity during the drying process by using the changes in chemical components before and after drying.

[0008] The research on the method for characterizing the processing intensity during the drying process is of positive significance for exploring the changing laws during the drying process, but each existing method has limitations. Summary of the Invention

[0009] To overcome the deficiencies of the prior art, the present invention provides a method for characterizing the processing intensity of a threshing and redrying roaster, in order to accurately quantify the processing intensity of the threshing and redrying roaster, so as to effectively guide the threshing and redrying processing technology and overcome the problem that the processing intensity of the threshing and redrying roaster cannot be quantitatively characterized.

[0010] To achieve the purpose, the present invention adopts the following technical solutions:

[0011] The method for characterizing the processing intensity of a threshing and redrying roaster according to the present invention is characterized by including the following steps:

[0012] Step 1: Online collect or offline detect the leaf moisture W1 of the leaves before drying in the threshing and redrying roaster and the leaf moisture W2 after drying, and calculate the water removal amount M1 of the leaves during the threshing and redrying process according to the material flow rate F of the material before the leaves enter the threshing and redrying roaster;

[0013] Step 2: Adjust the air volume balance of the threshing and redrying roaster. A measurement hole for supplying hot air is provided on the horizontal section air inlet pipe on the side of the threshing and redrying roaster and used as the detection point for the hot air pressure difference value. At the detection point, online collect the differential pressure value ΔP1 of the hot air differential pressure gauge and the temperature value T1 of the air temperature sensor;

[0014] Step 3. Collect the moisture content H of the hot air online near the detection point, and calculate the hot air density ρ1 according to the temperature value T1 and the moisture content H of the hot air:

[0015] Step 3.1. Calculate the partial pressure p of water vapor in the hot air according to Equation (1) q :

[0016]

[0017] In Equation (1): B is the standard atmospheric pressure value;

[0018] Step 3.2. Calculate the hot air density ρ1 according to Equation (2);

[0019]

[0020] Step 4. Calculate the hot air velocity ν1 according to Equation (3);

[0021]

[0022] Step 5. Calculate the hot air mass flow rate M2 according to Equation (4);

[0023]

[0024] In Equation (4), D represents the diameter of the hot air inlet pipeline;

[0025] Step 6. Calculate the characterization index of the processing intensity of the threshing and redrying roaster

[0026] The characteristic of the method for characterizing the processing intensity of the threshing and redrying roaster according to the present invention is also that the hot air density ρ1 in Step 3 can also be calculated according to the following process:

[0027] Calculate the saturated partial pressure P of water vapor in the hot air using Equation (5) s :

[0028]

[0029] In Equation (5), EXP represents the natural exponential function;

[0030] Calculate the partial pressure p of water vapor in the hot air according to Equation (6) q ;

[0031] p q = p s × RH (6).

[0032] In Step 1, the water removal amount M1 is obtained using Equation (7):

[0033]

[0034] In step 2, adjusting the air balance of the threshing and redrying roaster means adjusting the feeding end of the threshing and redrying roaster to a negative pressure of 0 to -30 micropascals and the discharging end to a negative pressure of -5 to -30 micropascals.

[0035] If the processing intensity characterization index A is between 20% and 50%, it indicates that the internal quality of the leaves after drying by the threshing and redrying roaster is relatively good.

[0036] The processing intensity characterization index A being between 20% and 50% is inversely proportional to the processing intensity of the threshing and redrying roaster.

[0037] A kind of electronic device of the present invention, including a memory and a processor, is characterized in that the memory is used to store a program for supporting the processor to execute the characterization method, and the processor is configured to execute the program stored in the memory.

[0038] A kind of computer-readable storage medium of the present invention, on which a computer program is stored, is characterized in that when the computer program is run by a processor, it executes the steps of the characterization method.

[0039] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0040] A method for characterizing the processing intensity of a threshing and redrying roaster provided by the present invention, from the perspective of tobacco chemistry, based on Dalton's law of partial pressures, using the law of conservation of mass in the threshing and redrying process, based on the principle of the volatilization of aroma components and the transformation of some high-molecular components during the threshing and redrying process, through the analysis of the properties of two main objects of mass transfer in the threshing and redrying process: leaves and hot air. The leaves are the source of mass transfer in the threshing and redrying process, and the hot air is the carrier and heat source of mass transfer in the threshing and redrying process. The low-boiling and volatile components in the leaves are transferred to the hot air along with the volatilization of water in the leaves during the threshing and redrying process. The volatilization amount of the low-boiling components in the leaves is characterized by the volatilization amount of water in the leaves, and at the same time, the saturation degree of the hot air, that is, the moisture content, is used to control the speed of moisture mass transfer. The processing intensity of the threshing and redrying roaster is characterized from two aspects: the total amount and speed of mass transfer between the leaves and the hot air in the threshing and redrying process. The present invention can use a quantitative method to characterize the processing intensity in the threshing and redrying process, and select different leaf processing intensities according to the processing quality characteristics and leaf structure requirements of different grades of tobacco leaf raw materials, thus effectively guiding the processing technology of the threshing and redrying roaster. Specific embodiments

[0041] The following further elaborates on the present invention in detail in conjunction with embodiments, but the embodiments do not limit the technical solutions of the present invention.

[0042] Unless otherwise specified, the professional terms involved shall refer to the "Cigarette Process Specification" (2016 Edition) compiled by the State Tobacco Monopoly Administration.

[0043] In this embodiment, a method for characterizing the processing intensity of a threshing and redrying baking machine is to use a technical index to characterize the processing intensity during the threshing and redrying baking process. This index is related to the water removal amount and the hot air mass flow rate during the threshing and redrying baking process, and is characterized by using the principles of material mass conservation and heat conservation during the baking process. The larger the material water removal amount M1 and the smaller the hot air mass flow rate M2, the smaller the value of the processing intensity A. The higher the hot air saturation degree, which is the moisture carrier in the threshed and redried leaves, the lower the dehydration speed of the leaves during the baking process, the higher the vapor partial pressure of the volatile components in the hot air, and the slower the volatilization speed of the aroma components during the baking process of the leaves, thereby reducing the loss of aroma components in the leaves. Specifically, the method for characterizing the processing intensity of the threshing and redrying baking machine includes the following steps:

[0044] Step 1: Online collect or offline detect the leaf moisture W1 and W2 before and after drying of the leaves in the threshing and redrying baking machine. According to the material flow rate F of the leaves before entering the threshing and redrying baking machine, calculate the water removal amount M1 during the threshing and redrying baking process using Equation (1);

[0045]

[0046] Step 2: Adjust the feeding end of the threshing and redrying baking machine to a negative pressure of 0 to -30 micro-Pascals and the discharging end to a negative pressure of -5 to -30 micro-Pascals, so as to adjust the wind force balance of the threshing and redrying baking machine. Set a measurement hole on the horizontal air inlet pipe on the side of the threshing and redrying baking machine where the hot air enters as the detection point for the hot air pressure difference value. Online collect the differential pressure value ΔP1 of the differential pressure gauge and the temperature value T1 of the air temperature sensor at this detection point;

[0047] Step 3: Online collect the moisture content H of the hot air near the detection point, and thus calculate the hot air density ρ1 according to the hot air temperature value T1 and the moisture content H:

[0048] Step 3.1: Calculate the water vapor partial pressure p in the hot air according to Equation (1) q :

[0049]

[0050] In Equation (1): B is the standard atmospheric pressure value;

[0051] Among them, the hot air density ρ1 can also be calculated according to the following process:

[0052] Calculate the saturated water vapor partial pressure P of the hot air using Equation (5) s :

[0053]

[0054] In Equation (5), EXP represents the natural exponential function;

[0055] Calculate the partial pressure p of water vapor in the hot air according to Equation (6) q ;

[0056] p q = p s ×RH(6)

[0057] Step 3.2: Calculate the hot air density ρ1 according to Equation (2);

[0058]

[0059] Step 4: Calculate the hot air velocity ν1 according to Equation (3);

[0060]

[0061] Step 5: Calculate the hot air mass flow rate M2 according to Equation (4);

[0062]

[0063] In Equation (4), D represents the diameter of the hot air inlet pipeline;

[0064] Step 6: Calculate the characterization index of the processing intensity of the threshing and redrying roaster

[0065] If the A value of the processing intensity of the threshing and redrying roaster is between 20% and 50%, the internal quality of the leaves after drying by the threshing and redrying roaster is relatively good, and it can basically maintain the sensory quality characteristics of the raw materials before baking the leaves, and the baking aroma in the tobacco aroma increases less. As the A value increases, the processing intensity of the threshing and redrying roaster decreases; as the A value decreases, the processing intensity of the threshing and redrying roaster increases.

[0066] In this embodiment, an electronic device includes a memory and a processor. The memory is used to store a program that supports the processor to execute the above method, and the processor is configured to execute the program stored in the memory.

[0067] In this embodiment, a computer-readable storage medium stores a computer program, and when the computer program is run by a processor, it executes the steps of the above method.

[0068] Embodiment 1

[0069] Step 1. In 2022, the moisture content of the leaves of Yunnan A-grade central tobacco leaves entering the threshing and redrying roaster was 16.80%, the material flow rate before the leaves entered the threshing and redrying roaster was 8000 kg / h, and the moisture content of the discharged leaves after baking was 12.10%. The calculated water removal amount M1 during the threshing and redrying baking process was 427.7 kg / h.

[0070] Step 2. Adjust the air balance of the threshing and redrying roaster so that the feeding end of the threshing and redrying roaster is adjusted to a slightly negative pressure of 0 to -30 micropascals, and the discharging end is adjusted to a negative pressure of -5 to -30 micropascals. A measuring hole is set on the horizontal air inlet pipe on the side of the threshing and redrying roaster where hot air enters as the hot air velocity detection point.

[0071] The diameter D of the air inlet pipe is measured to be 300 mm; the differential pressure detection value △P of the online differential pressure gauge is 24 Pa; the temperature T = 85.1°C at the hot air velocity detection point is collected using a temperature sensor.

[0072] Step 3. The relative humidity RH of the hot air is collected online to be 61.6%, specifically as follows:

[0073] First, through the air relative humidity RH and the air temperature T, the air density ρ1 is calculated to be 0.8513 kg / m 3 ;

[0074] Step 4. Through the differential pressure detection value △P of the online differential pressure gauge and the air density ρ1, the air velocity ν1 is calculated to be 7.51 m / s according to Equation (3).

[0075] Step 5. The hot air mass flow rate M2 is calculated to be 1626.7 kg / h according to Equation (4).

[0076] Step 6. The characterization index A of the processing intensity of the threshing and redrying roaster is calculated to be 26.3%.

[0077] After the Yunnan A-grade central tobacco leaves in 2022 were baked through the above process parameter combination, due to the large material flow rate of the leaves and the relatively small design of the hot air volume, the volatilization amount of low-boiling components in the leaves was relatively small, resulting in an improvement in the uniformity of the moisture content of the baked leaves.

[0078] From the comparative evaluation and analysis of the sensory quality before and after the threshing and redrying roaster, for the leaves dried using the above process parameter combination, the baking aroma is increased, the aroma quality is improved, the aroma quantity is increased, the green and miscellaneous odors are reduced, and the irritation is decreased. Overall, the internal sensory quality of the baked leaves is significantly improved.

Claims

1. A method for characterizing the processing strength of a threshing and redrying baking machine, characterized in that, It includes the following steps: Step 1: Online collect or offline detect the moisture content W1 of the leaves before drying in the threshing and redrying baking machine and the moisture content W2 of the leaves after drying. According to the material flow rate F of the materials before the leaves enter the threshing and redrying baking machine, calculate the water removal amount M1 of the leaves during the threshing and redrying process; Step 2: Adjust the air volume balance of the threshing and redrying baking machine. A measurement hole for hot air to enter is provided on the horizontal air inlet pipeline on the side of the threshing and redrying baking machine and is used as the detection point for the hot air pressure difference value. At the detection point, online collect the differential pressure value ΔP1 of the hot air differential pressure gauge and the temperature value T1 of the air temperature sensor; Step 3: Online collect the moisture content H of the hot air near the detection point, and thus calculate the hot air density ρ1 according to the temperature value T1 and the moisture content H of the hot air: Step 3.

1. Calculate the partial pressure p of water vapor in the hot air according to Equation (1) q : In formula (1): B is the standard atmospheric pressure value; Step 3.2: Calculate the hot air density ρ1 according to formula (2); Step 4: Calculate the hot air velocity ν1 according to formula (3); Step 5: Calculate the hot air mass flow rate M2 according to formula (4); In formula (4), D represents the diameter of the hot air inlet pipeline; Step 6: Calculate the characterization index of the processing intensity of the threshing and redrying roaster 2. The characterization method of the processing intensity of the threshing and redrying roaster according to claim 1, characterized in that, The hot air density ρ1 in Step 3 can also be calculated according to the following process: Calculate the saturated water vapor partial pressure P of the hot air using Equation (5). s : In formula (5), EXP represents the natural exponential function; Calculate the partial pressure p of water vapor in the hot air according to Equation (6). q ; p q = p s × RH (6).

3. The characterization method of the processing strength of the threshing and redrying baking machine according to claim 1, wherein: In Step 1, the water removal amount M1 is obtained by using formula (7); 4. The method for characterizing the processing intensity of a threshing and redrying baking machine according to claim 1, wherein: In Step 2, adjusting the air volume balance of the threshing and redrying baking machine means adjusting the feeding end of the threshing and redrying baking machine to a negative pressure of 0 to -30 micropascals and the discharging end to a negative pressure of -5 to -30 micropascals.

5. The characterization method for the processing intensity of the threshing and redrying baking machine according to claim 1, wherein: If the processing intensity characterization index A is between 20% and 50%, it means that the internal quality of the leaves after drying by the threshing and redrying baking machine is relatively good.

6. The characterization method for the processing intensity of the threshing and redrying baking machine according to claim 1, wherein: The processing intensity characterization index A being between 20% and 50% is inversely proportional to the processing intensity of the threshing and redrying baking machine.

7. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store a program for supporting the processor to execute any one of the characterization methods in claims 1-6, and the processor is configured to execute the program stored in the memory.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program runs on the processor, it executes the steps of any one of the characterization methods in claims 1-6.

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