High-stability loosening and moisture regaining outlet moisture content control method for cigarette cut tobacco production

Abstract

The invention belongs to the technical field of tobacco processing, and relates to a method for controlling the moisture content of a high-stability loosening and moisture regaining outlet for cigarette primary processing, which comprises the following steps: 1, detecting the moisture content of the outlet; the outlet moisture content detection comprises the steps of determining the water adding duration T2, collecting the inlet moisture S10 and collecting the outlet moisture S20; 2, water adding control; the water adding control comprises the steps of establishing a model and determining an algorithm; the method comprises the following steps: determining a fixed water adding coefficient according to a leaf group formula sequence, and determining a fixed water adding correction coefficient, a feed-forward water adding coefficient and correction coefficient, and an experience water adding coefficient and correction coefficient through a self-learning system in combination with an instantaneous flow rate, a steam water content, a steam flow rate, an inlet moisture meter measurement value and an outlet moisture meter measurement value; through combination of feedforward control, an empirical correction coefficient and a fixed water adding amount and assistance of an optimization algorithm, accurate control of the moisture content is realized, the moisture content of a loosening and moisture regaining outlet is ensured to be stable, and the standard deviation of the moisture content is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of tobacco processing, and relates to a method for controlling the outlet moisture content with high stability in the cut tobacco drying and conditioning process. Background Art

[0002] Drying and conditioning is one of the important processes in the cut tobacco production process. Drying and conditioning is a process in the cut tobacco process that loosens, warms, and humidifies the cut tobacco blocks through physical and heat-moisture treatment. Its technological function is to increase the moisture content and temperature of the tobacco leaves, improve the physical properties of the tobacco leaves, enhance the processability of the tobacco leaves, make the tobacco leaves uniform and loose, and meet the requirements of subsequent cut tobacco processes. And remove green and miscellaneous odors, pungent odors, etc., retain the original tobacco fragrance to the greatest extent, and improve the sensory quality. Drying and conditioning combines mechanical loosening and heat-moisture treatment to provide cut tobacco slices with stable physical properties and optimized sensory qualities for subsequent cut tobacco processes. Its process accuracy and equipment stability are the core links to ensure cigarette quality.

[0003] Moisture control is the "lifeblood" of the drying and conditioning process, and its accuracy directly determines the physical processability, sensory quality, production cost, and process stability of the entire chain of tobacco leaves. Through intelligent control, refined equipment maintenance, and process parameter optimization, the efficiency of drying and conditioning can be maximized, laying a foundation for high-quality cigarette production.

[0004] However, in the existing drying and conditioning process, the outlet moisture of drying and conditioning adopts feedback control, that is, the water addition amount is controlled according to the outlet moisture content to meet the outlet moisture content control index. The existing drying and conditioning process has the following defects:

[0005] 1. The quality of the outlet moisture fluctuates unstably

[0006] The outlet moisture is affected by factors such as the inlet moisture of the incoming material, steam quality, material flow rate, environmental temperature and humidity, etc., and accurate control cannot be achieved. Adjustment by manual experience leads to unstable quality fluctuations

[0007] 2. Environmental factors, especially steam quality, have a great impact. It is difficult to measure the quality of steam, whether it is saturated steam, and it has a great impact on moisture control; this makes the control of the first batch of production every day, especially the first batch at the end of each shift, the most difficult

[0008] 3. For different incoming materials, the moisture content of the leaf group formula fluctuates greatly (10 - 14%)

[0009] The differences in the incoming materials are relatively large, with differences in moisture content in different years, origins, grades, and colors, water absorption and other quality characteristics of the cut tobacco slices affecting the detection results of the moisture meter, and the moisture meter measures the surface moisture

[0010] 4. System control delay

[0011] The distance between the water addition point (the water addition nozzle of the conditioning cylinder is located at the feeding end) and the detection point (the outlet moisture analyzer) is relatively long. After the water addition amount is adjusted, it takes 3 to 5 minutes to detect the impact, and the water addition correction value obtained from the detection and feedback of the moisture analyzer cannot be accurately applied to the current cigarette package.

[0012] The control method of the existing loosening and conditioning process lags behind, the measurement result error is relatively large, it is difficult to achieve precise control, resulting in a low standard deviation of the moisture content at the outlet of the loosening and conditioning, only maintaining at about 0.6.

[0013] Therefore, how to improve the process performance of the loosening and conditioning process and enhance the stability of the moisture content at the outlet of the loosening and conditioning has always been a technical issue concerned by tobacco manufacturers. Summary of the Invention

[0014] The technical solution adopted by the present invention to solve the technical problem is: a method for controlling the moisture content at the outlet of high-stability loosening and conditioning in cigarette leaf processing, including the following steps:

[0015] Step 1, detecting the moisture content at the outlet; the detection of the moisture content at the outlet includes: determining the water addition duration T2, collecting the inlet moisture S10, and collecting the outlet moisture S20;

[0016] Step 2, water addition control; the water addition control includes: establishing a model and determining an algorithm;

[0017] Specifically, establishing the model includes: combining the operation mechanism of the loosening and conditioning, establishing a control model for the outlet moisture of the loosening and conditioning, and updating the water addition coefficient according to the currently calculated outlet moisture deviation in real time, so that the PLC automatically controls the moisture content at the outlet of the loosening and conditioning;

[0018] Determining the algorithm includes: the water addition coefficient is:

[0019] Out = IN1 * IN2 + IN3 * IN4 + (IN5 - IN1 * IN2) * IN6 (1)

[0020] In formula (1), IN1 represents the set value of the water addition coefficient, which is determined by the brand; IN2 represents the ratio of the historical water addition amount and the theoretical water addition amount of this brand; IN3 represents the feed-forward water addition coefficient; IN4 represents the feed-forward control correction coefficient; IN5 represents the empirical water addition coefficient; IN6 represents the empirical water addition correction coefficient.

[0021] Preferably, in the step 1, the step of determining the water addition duration T2 includes: taking the signal of the electronic belt scale having material as the timing start point, and timing through the PLC timer; taking the time point when the material on the electronic belt scale reaches one-third of the inlet end of the drum as the start water addition time point T1; taking the time T3 from the material on the electronic belt scale to the outlet moisture analyzer, and the water addition duration T2 is: T2 = T3 - T1.

[0022] Preferably, in the step 1, the collection step of the inlet moisture S10 includes: considering the water absorption of the tobacco leaves according to the original data of the tobacco leaves, and initially classifying, sorting and distributing the leaf group formula; the cigarette packs in the order of the leaf group formula enter the slicing, detecting and recording the moisture S1 of each pack of tobacco leaves corresponding to the leaf group formula, comparing with the current moisture meter detection value S11, and performing linear fitting on the two sets of data; adjusting the parameters of the moisture meter, calibrating the inlet moisture meter, and taking this moisture as the inlet moisture S10 of the leaf group; the original data includes: grade, origin, year.

[0023] Preferably, in the step 1, the collection step of the outlet moisture S20 includes: calculating the total water addition amount Q of this brand according to the total weight W of the leaf group formula, the median moisture content S0 specified in the tobacco slice process standard, and the median moisture content standard S01 of the loose rewetting outlet moisture content specified in the process technical standard of this brand, that is, Q = W×(S01 - S0), and adopting a fixed water addition amount; recording the current process conditions, and successively measuring the display value S2 and the oven value S21 of each pack of tobacco slices of the leaf group formula shown on the outlet moisture meter with a fixed water addition amount according to the collection time, performing linear fitting on the two sets of data, adjusting the parameters of the moisture meter, calibrating the outlet moisture meter, and taking this moisture as the outlet moisture S20 of the leaf group;

[0024] The current process conditions include: steam moisture content, steam flow rate.

[0025] Preferably, in the step 2, establishing the model further includes: accessing data to the model, data processing, data governance, data pushing;

[0026] In the step of accessing data to the model, the accessed data includes: leaf group formula data from MES, moisture meter detection values and oven values when a new brand is put into production, online real-time measurement values of the moisture meter, exhaust dampers, negative pressure, steam flow rate, steam pressure, and real-time acquisition values of steam moisture content that meet the process conditions of the loose rewetting process equipment;

[0027] Data processing includes: examining linearity, eliminating outliers, and converting data types;

[0028] Data governance includes: establishing a stack according to the water addition duration T2 of the cigarette pack in the cylinder, corresponding the data to the leaf group formula one by one, and establishing a database;

[0029] Data pushing includes: pushing the data to the self-learning system for processing.

[0030] More preferably, in the formula (1) of the step 2, IN3 is the difference between the inlet moisture meter detection value and the standard value; IN4 is the optimal value of the feedback water addition provided by the self-learning system; IN5 is the optimal value of the water addition coefficient of this brand provided by the self-learning system; IN6 is the correction value pushed by the self-learning system according to the current detection value of the outlet moisture meter, the standard value, the steam moisture content, and the historical data.

[0031] The beneficial effects of the present invention are as follows:

[0032] 1. By combining feedforward control, empirical correction coefficient and fixed water addition amount, and supplemented by an optimization algorithm, the present invention realizes precise control of the moisture content; therefore, the present invention improves the process performance of the loose re-drying process and enhances the stability of the moisture content at the outlet of the loose re-drying.

[0033] 2. The present invention introduces a self-learning system, integrating data analysis, push and control: fully considering the influencing factors and correlation analysis of the moisture content at the outlet of the loose re-drying, based on the water addition amount benchmark calculated according to the leaf group formula and process technical standards, using the self-learning system to regularly calculate and update the dynamic water addition adjustment value in combination with the database, and real-time push the water addition amount to realize the double-closed-loop automatic control of the outlet moisture content.

[0034] 3. The present invention can significantly reduce the fluctuation of the outlet moisture content. The algorithm is self-learning, self-adaptive and self-optimizing. By learning the manual control experience and the historical data of model control, the model parameters are continuously optimized and updated, and the stability and accuracy of the process quality control of the loose re-drying are continuously improved. As long as the formula remains unchanged, it will only become more and more accurate. The standard deviation is reduced to 0.421%; therefore, the control of the present invention is more precise and stable.

[0035] 4. The present invention can dynamically adjust the water addition coefficient according to the differences in raw material quality, effectively overcoming the challenges brought by raw material fluctuations, and improving the flexibility and adaptability of the control method. This control method can be easily integrated into the existing production line by establishing the upper system and the bottom PLC channel, reducing the cost and cycle of technical transformation. The method is clear and the algorithm is obvious, which can be replicated and promoted. In addition to the excellent performance in the processing of tobacco leaves with A brand formula, the present invention also shows the potential for stable control in the processing of other brands, indicating its wide applicability and market prospects; therefore, the present invention has flexible adaptability and can be promoted.

[0036] 5. The present invention can significantly reduce the fluctuation of the moisture content of tobacco leaves at the outlet of the loose re-drying, reduce the possibility of unqualified products, and improve the overall quality and consistency of the products; therefore, the present invention provides a stable incoming material level guarantee for the subsequent processes, and the quality of cut tobacco and the process are stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is the control schematic diagram of a high-stability loose re-drying outlet moisture content control method for cigarette cut tobacco of the present invention;

[0038] Figure 2 is the algorithm block diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] Next, the relevant technologies in the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0040] As Figures 1 - 2 shown, this embodiment provides a method for controlling the moisture content at the outlet of high-stability loose re-drying:

[0041] 1. The detection of the moisture content at the outlet mainly adopts the following strategies

[0042] 1.1 Time determination

[0043] 1.1.1 Determination method: The signal of the electronic belt scale indicating the presence of material is used as the starting point for timing, and the timing is carried out through the PLC timer.

[0044] 1.1.2 Determination of the water addition time: The time point T1 when the material reaches one-third of the inlet end of the drum from the moment the electronic belt scale detects the presence of material is taken as the start time of water addition;

[0045] 1.1.3 Determination of the water addition duration (the residence time of each bale of tobacco leaves in the drum) T2: Since the incoming material flow rate is constant, the time T3 from the moment the electronic belt scale detects the presence of material to the moment the material reaches the outlet moisture meter, T2 = T3 - T1.

[0046] 1.2 Data acquisition and recording

[0047] 1.2.1 Inlet moisture acquisition

[0048] 1.2.1.1 Based on the original data such as the tobacco leaf grade, origin, and year, mainly considering its water absorption, the leaf group formula is initially classified, sorted, and distributed;

[0049] 1.2.1.2 The tobacco bales in the order of the leaf group formula enter the slicing;

[0050] 1.2.1.3 Detect and record the moisture content S1 of each bale of tobacco leaves corresponding to a certain brand leaf group formula, compare it with the current moisture meter detection value S11, perform linear fitting on the two sets of data to obtain the fitting equation, adjust the parameters of the moisture meter, calibrate the inlet moisture meter, and take this moisture as the inlet moisture S10 of the leaf group.

[0051] 1.2.2 Outlet moisture acquisition

[0052] 1.2.2.1 Based on the total weight W of the leaf group formula, the median moisture content S0 specified in the tobacco leaf process standard, and the median moisture content standard S01 at the outlet of loose re-drying specified in the process technical standard of this brand, calculate the total water addition amount Q of this brand, that is, Q = W × (S01 - S0), and adopt a fixed water addition amount (that is, add water according to the ratio of (IN1 = S01 - S0)).

[0053] 1.2.2.2 Record the current process conditions (steam moisture content, steam flow rate), and successively measure the display value S2 of the outlet moisture meter and the oven value S21 of each pack of tobacco leaves in the leaf group formula according to the above collection time, with a fixed water addition amount. Perform linear fitting on the two sets of data to obtain a fitting equation, adjust the parameters of the moisture meter, calibrate the outlet moisture meter, and use this moisture as the outlet moisture S20 of the leaf group.

[0054] 2. Water addition control

[0055] 2.1 Model establishment

[0056] 2.1.1 Elements involved: influencing factors and process parameters such as steam moisture content, applied steam flow rate, ejector steam pressure, instantaneous incoming material flow rate, inlet moisture, brand, etc.

[0057] 2.1.2 Establish a model: Combine the operating mechanism of the loose re-drying to establish a control model for the outlet moisture of the loose re-drying. Update the water addition coefficient according to the currently calculated outlet moisture deviation in real time, so that the PLC automatically controls the outlet moisture content of the loose re-drying. The control block diagram is as Figure 1 shown.

[0058] 2.1.3 Model operation

[0059] 2.1.3.1 Data access:

[0060] ① Leaf group formula data from the MES; (MES, Manufacturing Execution System, the abbreviation of Manufacturing Execution System)

[0061] ② Moisture meter detection value and oven value when a new brand is put into production;

[0062] ③ Online real-time measurement value from the moisture meter;

[0063] ④ Real-time acquisition values of the exhaust damper, negative pressure, steam flow rate, steam pressure, and steam moisture content of the process equipment (loose re-drying) that meet the process conditions.

[0064] 2.1.3.2 Data processing: Examine linearity, eliminate outliers, convert data types, etc.

[0065] 2.1.3.3 Data governance: Establish a stack according to the residence time T2 of the cigarette pack in the cylinder, correspond the data with the leaf group formula one by one, and establish a database.

[0066] 2.1.3.4 Data push: Push the data to the self-learning system for processing.

[0067] 2.2 Algorithm determination

[0068] 2.2.1 Algorithm Block Diagram (as Figure 2 shown)

[0069] 2.1.2 Algorithm: Out = IN1 * IN2 + IN3 * IN4 + (IN5 - IN1 * IN2) * IN6 (1)

[0070] IN1 - Set value of water addition coefficient, determined by grade;

[0071] IN2 - Ratio of historical water addition amount to theoretical water addition amount for this grade;

[0072] IN3 - Feedforward water addition coefficient, which is the difference between the detected value of the inlet moisture meter and the standard value;

[0073] IN4 - Feedforward control correction coefficient, and the optimal value of feedback water addition is provided by the self - learning system;

[0074] IN5 - Empirical water addition coefficient, and the optimal value of the water addition coefficient for this grade is provided by the self - learning system;

[0075] IN6 - Empirical water addition correction coefficient, and the correction value pushed by the self - learning system based on the current detected value of the outlet moisture meter, standard value, steam moisture content, historical data, etc.

[0076] Embodiment

[0077] I. Considering the influencing factors of outlet moisture comprehensively to reduce the fluctuation of outlet moisture

[0078] 1. For the first batch of each day, it is necessary to calculate the influence of the current day's steam moisture content and exhaust negative pressure on the materials in the cylinder, and automatically select the corresponding water addition set value in combination with the previous process conditions.

[0079] 2. The head of the material should ensure the non - steady state time, which directly determines the control index of the current batch, and special treatment for the head and tail of the material has been carried out.

[0080] 3. For different grades, different water addition coefficients are adopted, and the water addition set value is corrected in combination with the physical properties of the incoming materials

[0081] 4. Considering the time lag between the current outlet moisture and water addition control, realize the automatic closed - loop control of the water addition amount

[0082] II. Self - learning and self - optimization within and between batches

[0083] 1. Learning within batches and self - correction: Within a batch, use the current data to calculate the outlet moisture deviation and water addition adjustment value, learn the experience of the model itself, and adaptively correct the parameters of the steady - state control model in the material;

[0084] 2. Learning between batches and self - optimization: Between batches, use historical data to learn the manual control experience or excellent practices of model self - learning control, and continuously optimize the control models for the head, middle, and tail of the material;

[0085] 3. Grade adaptability and transferability: Learn the manual control experience of new grades, update the model parameters automatically after accumulating a small number of batches, and can quickly adapt to new grades.

[0086] In summary, the present invention combines feedforward control, empirical correction coefficient and fixed water addition, supplemented by an optimization algorithm, to achieve precise control of the moisture content, ensure the stability of the moisture content at the outlet of the loose rewetting process, and reduce the standard deviation of the moisture content to 0.421%; therefore, the present invention improves the process performance of the loose rewetting process and enhances the stability of the moisture content at the outlet of the loose rewetting.

[0087] It should be emphasized that the above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for controlling the moisture content of a high-stability loose rehumidification outlet of cigarette shreds, characterized in that: The following steps are involved: Step 1: Detection of outlet moisture content; The outlet moisture content detection includes: determining the water addition time T2, collecting the inlet moisture S10, and collecting the outlet moisture S20; Step 2: water addition control; the water addition control includes: establishing a model and determining an algorithm; The model establishment specifically includes: combining the operation mechanism of loose moisture regain, establishing a loose moisture regain outlet moisture control model, updating the water addition coefficient according to the current outlet moisture deviation calculated in real time, and controlling the moisture content of the loose moisture regain outlet; The determination algorithm includes: the water addition coefficient is: Out=IN1*IN2+IN3*IN4+(IN5-IN1*IN2)*IN6 (1) In formula (1), IN1 represents the set value of the water addition coefficient; IN2 represents the ratio of the historical water addition amount to the theoretical water addition amount of the brand; IN3 represents the feedforward water addition coefficient; IN4 represents the feedforward control correction coefficient; IN5 represents the empirical water addition coefficient; IN6 represents the empirical water addition correction coefficient.

2. The method for controlling moisture content at a high stability loose rehumidification outlet of cigarette shreds according to claim 1, characterized in that: In step 1, the step of determining the water adding time T2 includes: taking the electronic belt scale with material signal as the timing starting point, and taking the time from the electronic belt scale with material to the material arriving at the drum entrance as the start time of water adding T1; taking the time from the electronic belt scale with material to the material arriving at the outlet moisture meter T3, the water adding time T2 is: T2=T3-T1.

3. The method for controlling moisture content at a high stability loose rehumidification outlet of cigarette shreds according to claim 1, characterized in that: In the step 1, the step of collecting the moisture content at the inlet S10 includes: considering the water absorption of tobacco leaves according to the original data of tobacco leaves, and preliminarily classifying and sorting and issuing the leaf group formula; the tobacco packages in the order of the leaf group formula enter the slice, detecting and recording the moisture content of each package of tobacco leaves corresponding to the leaf group formula S1, and comparing the current moisture meter detection value S11, the two sets of data are linearly fitted; adjusting the parameters of the moisture meter, calibrating the inlet moisture meter, and using the moisture content as the inlet moisture content of the leaf group S10; the original data includes: grade, origin, and year.

4. The method for controlling moisture content at a high stability loose rehumidification outlet of cigarette shreds according to claim 1, characterized in that: In the step 1, the outlet moisture content S20 collection step includes: calculating the total amount of water added Q of the brand, that is, Q=W×(S01-S0), according to the total weight W of the leaf group formula and the median moisture content S0 specified in the tobacco sheet process standard and the median moisture content S01 of the loose regain outlet moisture content specified in the process technology standard of the brand, using a fixed amount of water; recording the current process conditions, measuring the displayed value S2 and the oven value S21 of the outlet moisture meter of each pack of tobacco sheets of the leaf group formula with a fixed amount of water added in sequence according to the collection time, performing linear fitting on the two sets of data, adjusting the parameters of the moisture meter, calibrating the outlet moisture meter, and taking the moisture as the outlet moisture S20 of the leaf group; The current process conditions include: steam moisture content and steam flow rate.

5. The method for controlling moisture content at a high stability loose rehumidification outlet of cigarette shreds according to claim 1, characterized in that: In step 2, the model building also includes: connecting data to the model, data processing, data governance, and data push; In the data access model step, the accessed data include: leaf group formula data from MES, moisture meter detection values ​​and oven values ​​when new brands are put into use, online real-time measurement values ​​from moisture meters, dehumidification dampers that meet process conditions of loose rehumidification process equipment, negative pressure, steam flow, steam pressure, and steam moisture content real-time collection values; The data processing includes: examining linearity, eliminating outliers, and converting data types; The data management includes: according to the water-adding time T2 of the cigarette pack in the cylinder, a stack is established, the data and the leaf group formula are matched one by one, and a database is established; The data pushing includes: pushing the data to the self-learning system for processing.

6. A method for controlling moisture content at a high stability loose rehumidification outlet of cigarette shreds according to claim 5, characterized in that: In the formula (1) of step 2, IN3 is the difference between the detection value of the inlet moisture meter and the standard value; IN4 is provided with the optimal value of the backfeed water addition by the self-learning system; IN5 is provided with the optimal value of the water addition coefficient of the brand by the self-learning system; IN6 is a correction value pushed by the self-learning system based on the current detection value of the outlet moisture meter, the standard value, the steam moisture content, and the historical data.

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