A double-return-flow mode threshing and winnowing process

Abstract

The application discloses a double-reflow mode threshing and winnowing process, which is applied to the end of a threshing and winnowing process, wherein the double-reflow mode comprises flag reflow and leaf reflow, and the end of the process comprises six devices, namely, a second-to-last threshing machine, a fourth-to-last winnower, a third-to-last winnower, a first-to-last threshing machine, a second-to-last winnower and a first-to-last winnower; the six devices at the end of the process participate in a circulation process of the double-reflow mode; ten double-reflow processes are formed by combining different arrangement processes and reflow modes of the six devices at the end of the process, so that the quality of tobacco leaf structure can be improved and the loss of tobacco leaves can be reduced without increasing the number of threshing machines and the number of times of winnowing.

Description

Technical Field

[0001] This invention relates to the field of leaf-beating air separation technology, specifically to a leaf-beating air separation process with a dual-recirculation mode. Background Technology

[0002] Leaf threshing and air separation is a crucial step in tobacco re-drying. Its purpose is to tear the tobacco leaves using a threshing machine, and then separate the clean leaves from the stems using an air separator. Due to the characteristics of tobacco leaves, the tearing rate of a single-stage threshing machine is approximately 40%-80%, and the air separation efficiency of a single-stage air separator is approximately 20%-60%. To ensure good air separation, maintain a clean leaf structure, and reduce tobacco dust loss, the leaf threshing and air separation process involves a complex layout of multiple stages of threshing machines and air separators connected in a specific sequence.

[0003] The practically applied process modes include a four-stage leaf threshing and eleven-times-air separation and one-stem return mode, a four-stage leaf threshing and fifteen-times-air separation and one-stem return mode, and a five-stage leaf threshing and eighteen-times-air separation and one-stem return mode. Their common feature is that, except for the stem return (stem recirculation), the remaining equipment layout adopts a sequential series process. The shortcomings of the currently used series-type leaf threshing and air separation process are that fewer equipment stages result in greater leaf breakage and higher losses. More equipment stages improve the quality of tobacco leaf structure and reduce losses, but require higher investment, larger footprint, and higher energy consumption.

[0004] Due to the persistent drawbacks of the serial process mode, Chinese patent CN1257671A discloses a cyclic air separation method for stem and blade sorting, such as... Figure 1 As shown, a scheme is disclosed in which the blades and leaf stems are returned to a certain air separator in the upstream stage of the process for recirculation and resorting. However, this method only gives a relatively broad concept and does not provide a dual recirculation process flow that can be used in actual production. Therefore, the present invention aims to provide a dual recirculation air separation process that can improve the structural quality of tobacco leaves and reduce tobacco leaf loss without increasing the number of leaf threshing machines and the number of tobacco leaf air separations. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes ten dual-recirculation process modes with better air separation effects. Simulation calculations are performed based on the recirculation process, and equation fitting is performed using the simulation results to accurately determine the speed of the last leaf-beating machine's roller and the recirculation efficiency of the dual-recirculation method. The calculated speed of the last leaf-beating machine's roller and the recirculation efficiency of the dual-recirculation method are then used for automatic control of leaf-beating air separation. This method has the advantages of high efficiency, high model accuracy, and no interference with the production process. It can effectively leverage the process quality effect of the dual-recirculation process mode, improve the structural quality of the leaf-beating and re-drying blades, and reduce breakage and loss during the leaf-beating air separation process.

[0006] This invention provides a dual-recirculation leaf-trimming air distribution process, which includes flag recirculation and leaf recirculation. It is applied at the end of the leaf-trimming air distribution process, and six devices at the end of the process participate in the cyclic flow of the dual-recirculation mode. The six devices at the end include: the second-to-last leaf trimmer, the fourth-to-last air distributor, the third-to-last air distributor, the first-to-last leaf trimmer, the second-to-last air distributor, and the first-to-last air distributor.

[0007] When the layout order of the six end devices is: second to last leaf trimmer → fourth to last sorter → third to last air distributor → second to last air distributor → last air distributor → last leaf trimmer, the return flow method is:

[0008] Recirculation Method 1: The material after leaf removal by the last leaf remover flows back to the fourth-to-last air separator; the second-to-last air separator separates the clean blades, which then flow back to the third-to-last air separator; or

[0009] Recirculation Method Two: The material after leaf removal by the last leaf remover flows back to the fourth-to-last air distributor; the clean blades separated by the second-to-last air distributor also flow back to the fourth-to-last air distributor; or

[0010] Return method three: The material after the last leaf-breaking machine breaks the leaves flows back to the third-to-last air separator, and the clean leaves are separated by the second-to-last air separator and flow back to the third-to-last air separator;

[0011] When the layout order of the six end devices is: second to last leaf trimmer → fourth to last air separator → third to last air separator → last leaf trimmer → second to last air separator → last air separator, the recirculation method is:

[0012] Recirculation Method 4: Material separated by the last air separator is recirculated to the fourth-to-last air separator; clean blades separated by the second-to-last air separator are recirculated to the third-to-last air separator; or

[0013] Recirculation Method 5: Material separated by the last air separator is recirculated to the fourth-to-last air separator; clean blades separated by the second-to-last air separator are recirculated to the fourth-to-last air separator; or

[0014] Recirculation Method Six: The material after air separation by the last air separator is returned to the second-to-last leaf-breaking machine. The second-to-last air separator separates the pure leaves, which are then returned to the third-to-last air separator; or

[0015] Return method seven: The material after being air-separated by the last air separator is returned to the second-to-last leaf-breaking machine. The second-to-last air separator separates the pure leaves, which are then returned to the fourth-to-last air separator.

[0016] When the layout order of the six end devices is: second to last leaf trimmer → fourth to last air separator → third to last air separator → second to last air separator → last leaf trimmer → last air separator, the recirculation method is:

[0017] Recirculation Method 8: Material separated by the last air separator is recirculated to the fourth-to-last air separator; clean blades separated by the second-to-last air separator are recirculated to the third-to-last air separator; or

[0018] Recirculation Method Nine: Material separated by the last air separator is recirculated to the third-to-last air separator; clean blades separated by the second-to-last air separator are recirculated to the third-to-last air separator; or

[0019] Recirculation Method 10: The material separated by the last air separator is returned to the fourth-to-last air separator, and the pure blades separated by the second-to-last air separator are returned to the fourth-to-last air separator.

[0020] Furthermore, the process also includes a process optimization step, which includes:

[0021] Step S1: Set the initial operating parameters of the equipment. The equipment will run according to these initial operating parameters, with the six end devices running in the process sequence of the dual reflux mode.

[0022] Step S2: Under normal operating conditions, measure the process parameters of the six terminal devices; the process parameters include: air separation efficiency, reflux efficiency, leaf tearing rate, leaf content of incoming material, output of pure tobacco leaves, and leaf structure;

[0023] Step S31: Based on the process parameters of the six end devices in this process, perform data fitting to obtain the calculation formula for the total efficiency of the process air classification;

[0024] Step S32: Based on the correspondence between the rotational speed of the last leaf-beating machine and the effective leaf-tearing rate, use data statistical software to fit and obtain the fitting equation between the rotational speed of the last leaf-beating machine and the effective leaf-tearing rate.

[0025] Step S41: Measure the air separation efficiency W3 of the third-to-last air separator and the air separation efficiency W4 of the fourth-to-last air separator;

[0026] Step S42: Measure the leaf tearing rate Y1 of the last leaf-removing machine;

[0027] Step S43: Determine the maximum value of leaf recirculation efficiency Hleaf and the maximum value of flag recirculation efficiency Hflag;

[0028] Step S51: Based on the air separation efficiency W3 of the third-to-last air separator, the air separation efficiency W4 of the fourth-to-last air separator, the maximum value of the leaf return efficiency H_leaf, the maximum value of the flag return efficiency H_flag, and the calculation formula of the total process air separation efficiency, determine the optimal value of the leaf return efficiency H_leaf and the optimal value of the flag return efficiency H_flag.

[0029] Step S52: Substitute the measured leaf tearing rate Y1 of the last leaf tearing machine into the fitting equation between the roller speed and the effective leaf tearing rate of the last leaf tearing machine to obtain the optimal value of the roller speed of the last leaf tearing machine.

[0030] Step S6: Reset the optimal values ​​of leaf return efficiency H_leaf, flag return efficiency H_flag, and the optimal values ​​of the last leaf and roller speed to the equipment.

[0031] Further, step S41 includes:

[0032] Adjust the air volume of the blade air separator, and under the condition that the blade with stem is ≤1.0%, measure the air separation efficiency W3 of the third to last air separator and the air separation efficiency W4 of the fourth to last air separator.

[0033] Further, step S42 includes:

[0034] Adjust the speed of the roller of the last leaf-beating machine, and take the average value of the leaf tearing rate Y1 within the range of loss rate: leaf tearing rate of 1:6 to 1:8.

[0035] Further, step S43 includes:

[0036] Adjust the flag return flow rate and leaf return flow rate to ensure that the actual flow rates of the fourth-to-last air separator, the third-to-last air separator, the second-to-last air separator, the first-to-last air separator, and the last leaf beater are all no greater than the rated flow rate and close to the rated flow rate. Then determine the maximum value of the leaf return efficiency Hleaf and the maximum value of the flag return efficiency Hflag.

[0037] Further, step S51 includes:

[0038] Substitute the air separation efficiency W3 of the third-to-last air separator, the air separation efficiency W4 of the fourth-to-last air separator, and the measured leaf tearing rate Y1 of the first-to-last leaf trimmer into the formula for calculating the total efficiency of the process air separation. At the same time, the leaf return efficiency H_leaf and the flag return efficiency H_flag are each substituted into the formula for calculating the total efficiency of the process air separation, starting from 1% and using each 1% increment as a gradient, until the leaf return efficiency H_leaf and the flag return efficiency H_flag are recursively calculated to their maximum values, thereby determining the optimal values ​​of the leaf return efficiency H_leaf and the flag return efficiency H_flag.

[0039] Further, in step S32, the fitting equation between the rotational speed x of the penultimate leaf-tearing machine roller and the effective leaf-tearing rate y is: y = 0.0000001x 6 -0.00002x 5 +0.00064x 4 -0.0115x 3 +0.0989x 2 -0.02537x+0.1825.

[0040] Furthermore, when the reflux method is reflux method one, the total efficiency W of the process air separation is calculated using the following formula:

[0041]

[0042] When the reflux method is reflux method two, the total efficiency W of the process air separation is calculated using the following formula:

[0043]

[0044] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine;

[0045] When the reflux method is reflux method three, the total efficiency W of the process air separation is calculated using the following formula:

[0046]

[0047] Furthermore, when the reflux method is reflux method four, the total efficiency W of the process air separation is calculated using the following formula:

[0048]

[0049] When the reflux mode is reflux mode five, the total efficiency W of the process air separation is calculated using the following formula:

[0050]

[0051] When the reflux mode is reflux mode six, the total efficiency W of the process air separation is calculated using the following formula:

[0052]

[0053] When the reflux mode is reflux mode seven, the total efficiency W of the process air separation is calculated using the following formula:

[0054]

[0055] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine.

[0056] Furthermore, when the reflux mode is reflux mode eight, the total efficiency W of the process air separation is calculated using the following formula:

[0057]

[0058] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine;

[0059] When the reflux mode is reflux mode nine, the total efficiency W of the process air separation is calculated using the following formula:

[0060]

[0061] When the reflux mode is reflux mode 10, the total efficiency W of the process air separation is calculated using the following formula:

[0062]

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0064] (1) The 10 dual reflux process modes proposed in this invention are more specific and practical, and can effectively improve the quality of tobacco leaf structure and reduce tobacco leaf loss.

[0065] (2) It achieves accurate control of the double reflux process parameters of the leaf threshing and air separation process. Without increasing or decreasing the equipment, it can effectively improve the total air separation efficiency and total leaf output rate of the leaf threshing and air separation process, reduce tobacco leaf loss, and save production costs. Attached Figure Description

[0066] Figure 1 A schematic diagram of the layout of the existing dual-reflow mode four-to-eleven-to-one reflow process.

[0067] Figure 2 This is a schematic diagram of the dual reflux mode in Example 2;

[0068] Figure 3 This is a schematic diagram of the four-to-eleven-to-one reflow process layout in Example 2;

[0069] Figure 4 This is a schematic diagram of the dual reflux mode in Example 3;

[0070] Figure 5 This is a schematic diagram of the dual reflux mode in Example 4;

[0071] Figure 6 This is a schematic diagram of the dual reflux mode in Example 5;

[0072] Figure 7 This is a schematic diagram of the dual reflux mode in Example 6;

[0073] Figure 8 This is a schematic diagram of the dual reflux mode in Example 7;

[0074] Figure 9 This is a schematic diagram of the dual reflux mode in Example 8;

[0075] Figure 10 This is a schematic diagram of the dual reflux mode in Example 9;

[0076] Figure 11 This is a schematic diagram of the dual reflux mode in Example 10;

[0077] Figure 12This is a schematic diagram of the dual reflux mode in Example 11. Detailed Implementation

[0078] The present invention will be further described in detail below through specific embodiments.

[0079] Leaf tearing rate: refers to the proportion of leaves torn off the tobacco stem after passing through the leaf threshing machine, with a maximum value of 100%.

[0080] Loss rate: refers to the proportion of fragments and tobacco dust with an effective diameter of less than 6mm among the leaves torn from the tobacco stem after passing through the leaf threshing machine. According to GB / T21137-2007 "Determination of tobacco leaf size", it is the proportion of material below 6mm sieve, with a maximum of 100%.

[0081] Effective leaf tearing rate: Leaf tearing rate minus loss rate, according to GB / T21137-2007 "Determination of tobacco leaf size", is the proportion of material with a 6mm sieve or larger, with a maximum value of 100%, and is expressed as y in this application.

[0082] Roller speed: refers to the speed of the leaf-tearing machine's rollers. The higher the roller speed, the higher the leaf-tearing rate, the higher the loss rate from 0, the higher the effective leaf-tearing rate initially, then decreases, and finally drops to 0.

[0083] Flag recirculation: refers to the process of separating and recirculating the blades and stems of the material using an air separator. The recirculation efficiency (flag recirculation efficiency) is denoted as H flag.

[0084] Leaf recirculation: refers to the process of separating and recirculating pure blades from the material using an air separator. The recirculation efficiency (leaf recirculation efficiency) is expressed as H_leaf.

[0085] Example 1

[0086] This embodiment provides an optimization method for a leaf-trimming air distribution process in a dual-recirculation mode. The dual-recirculation mode is designed for the flow layout of six devices at the end of the leaf-trimming air distribution process. The mode includes flag recirculation and leaf recirculation. The six devices at the end of the leaf-trimming air distribution process participate in the cyclic flow of the dual-recirculation mode. The six devices at the end include: the second-to-last leaf trimmer, the fourth-to-last air distributor, the third-to-last air distributor, the first-to-last leaf trimmer, the second-to-last air distributor, and the first-to-last air distributor.

[0087] The method includes:

[0088] Step S1: The six terminal devices are arranged and operate according to the dual-recirculation mode cyclic process. Preliminary operating parameters are set for the equipment, including the airflow of each leaf-beater, leaf recirculation efficiency, flag recirculation efficiency, and leaf-beater roller speed. The equipment operates with these preliminary operating parameters, with the six terminal devices operating in the dual-recirculation mode flow sequence.

[0089] Step S2: Under normal operating conditions, measure the process parameters of the six terminal devices; the process parameters include: air separation efficiency, reflux efficiency, leaf tearing rate, leaf content of incoming material, output of pure tobacco leaves, and leaf structure.

[0090] Step S31: Based on the process parameters of the six end devices in the process, perform data fitting to obtain the calculation formula for the overall efficiency of the process air separation.

[0091] Step S32: Based on the correspondence between the measured rotational speed x of the last leaf-beating machine and the effective leaf-tearing rate y, use statistical software such as Foxtable to fit the data and obtain the fitting equation between the rotational speed x of the last leaf-beating machine and the effective leaf-tearing rate y; y = 0.0000001x 6 -0.00002x 5 +0.00064x 4 -0.0115x 3 +0.0989x 2 -0.02537x+0.1825.

[0092] Step S41: Adjust the air volume of the blade air separator. Under the condition that the blade with stem is ≤1.0%, measure the air separation efficiency W3 of the third to last air separator and the air separation efficiency W4 of the fourth to last air separator.

[0093] Step S42: Adjust the speed of the roller of the penultimate leaf-beating machine. Within the range of loss rate: leaf tearing rate of 1:6 to 1:8, take the average value and measure the leaf tearing rate Y1 of the penultimate leaf-beating machine.

[0094] Step S43: Adjust the flag return flow rate and leaf return flow rate to ensure that the actual flow rates of the fourth-to-last air separator, the third-to-last air separator, the second-to-last air separator, the first-to-last air separator, and the first-to-last leaf beater are all not greater than the rated flow rate and are close to the rated flow rate. Then determine the maximum value of the leaf return efficiency H_leaf and the maximum value of the flag return efficiency H_flag.

[0095] Step S51: Substitute the air separation efficiency W3 of the third-to-last air separator, the air separation efficiency W4 of the fourth-to-last air separator, and the measured leaf tearing rate Y1 of the first-to-last leaf cutter into the formula for calculating the total efficiency of the process air separation. At the same time, the leaf return efficiency H_leaf and the flag return efficiency H_flag are each substituted into the formula for calculating the total efficiency of the process air separation, starting from 1% and using each 1% increment as a gradient, until the leaf return efficiency H_leaf and the flag return efficiency H_flag are recursively calculated to their maximum values, thereby determining the optimal values ​​of the leaf return efficiency H_leaf and the flag return efficiency H_flag.

[0096] Step S52: Substitute the measured leaf tearing rate Y1 of the last leaf-beating machine into the fitting equation between the rolling speed and leaf tearing rate of the last leaf-beating machine to obtain the optimal rolling speed of the last leaf-beating machine.

[0097] Step S6: Reset the optimal values ​​of leaf return efficiency H_leaf, flag return efficiency H_flag, and the optimal values ​​of the last leaf and roller speed to the equipment.

[0098] Example 2

[0099] In this embodiment, as Figure 2 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last separator → third to last air separator → second to last air separator → first to last air separator → first to last leaf-beating machine. The recirculation method is as follows: the material after leaf-beating by the first to last leaf-beating machine flows back to the fourth to last air separator, and the clean blades separated by the second to last air separator flow back to the third to last air separator.

[0100] Under this layout and recirculation mode, the total efficiency W of the process air separation is calculated using the following formula:

[0101]

[0102] In this embodiment, the existing production line operates at a rate of 12000 kg / h, with a capacity of 41% to 12% (process flow as follows). Figure 3 As shown in the figure, after implementing this invention, the relevant data simulation calculations are as follows:

[0103] (1) Calculation of actual leaf tearing rate and actual loss rate (as shown in Table 1):

[0104]

[0105] Table 1

[0106] After adjusting the roller speed according to the present invention, the actual leaf tearing rate of the entire process is 99.968%, the effective sheet output rate is 97.625%, and the actual loss rate is 2.344%.

[0107] (2) Calculation of effective leaf output rate, total air distribution efficiency, and total leaf output rate in the process (as shown in Table 2):

[0108]

[0109]

[0110] Table 2

[0111] After adjusting the leaf return efficiency and flag return efficiency according to the present invention, the overall effective leaf output rate is 97.62%, the overall air distribution efficiency is 97.37%, and the overall leaf output rate is 95.06%.

[0112] To further compare the effects of the invention with existing conventional processes and patent CN1257671A, simulation results were obtained under the same conditions as the original four-blade eleven-blade air distribution line, with a flow rate of 12000 kg / h. The comparison results are shown in Table 3.

[0113] unit:%

[0114]

[0115]

[0116] Table 3

[0117] Note: Economic benefits are calculated annually, based on an annual processing capacity of 1 million dan of tobacco leaves and the existing process losses. The economic benefits generated by saving losses are expressed in RMB 10,000 per year.

[0118] Example 3

[0119] like Figure 4 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last separator → third to last air separator → second to last air separator → first to last air separator → first to last leaf-beating machine. The recirculation method is as follows: the material after leaf-beating by the first to last leaf-beating machine flows back to the fourth to last air separator, and the clean blades separated by the second to last air separator flow back to the fourth to last air separator.

[0120] The formula for calculating the overall efficiency W of the process air separation is:

[0121]

[0122] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine.

[0123] Example 4

[0124] like Figure 5 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last separator → third to last air separator → second to last air separator → first to last air separator → first to last leaf-beating machine. The recirculation method is as follows: the material after leaf-beating by the first to last leaf-beating machine flows back to the third to last air separator, and the clean blades separated by the second to last air separator flow back to the third to last air separator.

[0125] The formula for calculating the overall efficiency W of the process air separation is:

[0126]

[0127] Example 5

[0128] like Figure 6As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → first to last leaf-beating machine → second to last air separator → first to last air separator. The recirculation method is as follows: the material after air separation by the first to last air separator is returned to the fourth to last air separator, and the clean leaves separated by the second to last air separator are returned to the third to last air separator.

[0129] The formula for calculating the overall efficiency W of the process air separation is:

[0130]

[0131] Example 6

[0132] like Figure 7 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → first to last leaf-beating machine → second to last air separator → first to last air separator. The recirculation method is as follows: the material after air separation by the first to last air separator is returned to the fourth to last air separator, and the clean leaves separated by the second to last air separator are returned to the fourth to last air separator.

[0133] The formula for calculating the overall efficiency W of the process air separation is:

[0134]

[0135] Example 7

[0136] like Figure 8 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → first to last leaf-beating machine → second to last air separator → first to last air separator. The recirculation method is as follows: the material separated by the first to last air separator is returned to the second to last leaf-beating machine, and the clean leaves separated by the second to last air separator are returned to the third to last air separator.

[0137] The formula for calculating the overall efficiency W of the process air separation is:

[0138]

[0139] Example 8

[0140] like Figure 9 As shown, the layout order of the six end devices is as follows: second to last leaf-beating machine → fourth to last air separator → third to last air separator → second to last air separator → first to last leaf-beating machine → first to last air separator. The return flow method is as follows: the material after air separation by the first to last air separator is returned to the second to last leaf-beating machine, and the clean leaves separated by the second to last air separator are returned to the fourth to last air separator.

[0141] The formula for calculating the overall efficiency W of the process air separation is:

[0142]

[0143] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine.

[0144] Example 9

[0145] like Figure 10 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → second to last air separator → first to last leaf-beating machine → first to last air separator. The recirculation method is as follows: the material after air separation by the first to last air separator is returned to the fourth to last air separator, and the clean leaves separated by the second to last air separator are returned to the third to last air separator.

[0146] The formula for calculating the overall efficiency W of the process air separation is:

[0147]

[0148] Among them, Y2 is the measured value of the leaf tearing efficiency of the second to last leaf-tearing machine.

[0149] Example 10

[0150] like Figure 11 As shown, the layout sequence of the six end devices is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → second to last air separator → first to last leaf-beating machine → first to last air separator. The recirculation method is as follows: the material after air separation by the first to last air separator is returned to the third to last air separator, and the clean leaves separated by the second to last air separator are returned to the third to last air separator.

[0151] The formula for calculating the overall efficiency W of the process air separation is:

[0152]

[0153]

[0154] Example 11

[0155] like Figure 12 As shown, the layout order of the six devices at the end is: second to last leaf-beating machine → fourth to last air separator → third to last air separator → second to last air separator → last leaf-beating machine → last air separator.

[0156] The reflux method is as follows: the material after being separated by the last air separator is refluxed to the fourth air separator from the bottom, and the pure blades separated by the second-to-last air separator are refluxed to the fourth air separator from the bottom.

[0157] The formula for calculating the overall efficiency W of the process air separation is:

[0158]

[0159] Example 12

[0160] Assuming the tobacco leaf content entering the process is 100% starting from the second-to-last threshing machine, after adjusting the parameters according to the reflux mode of Examples 2-11, the effect of implementing this invention is compared with the existing ordinary process and the four-threshing-eleven-point reflux process in patent CN1257671A. The results are calculated and compared under the same conditions as the original four-threshing-eleven-point threshing air distribution line at a flow rate of 12000 kg / h:

[0161] unit:%

[0162]

[0163]

[0164] According to calculations, under the 10 dual-recirculation process modes mentioned in this invention, the optimization method for leaf threshing and air separation parameters of this invention, without increasing or decreasing equipment, all outperform existing ordinary processes and patent CN1257671A. In actual production, taking a re-drying enterprise processing 1 million dan (1 dan = 50 kg) of raw tobacco annually, with a leaf content of approximately 70%, every 0.1% increase in leaf yield results in an additional 35,000 kg of leaves, which, based on the market price of tobacco leaves, would reduce tobacco leaf losses by 3.5 million yuan. Implementing the process model of this invention using the 10 processes provided by this invention, for every 1 million dan of tobacco leaves processed, 678,000 to 787,000 kg of tobacco leaves will be saved, reducing tobacco leaf costs by approximately 33.91 million to 39.37 million yuan compared to the current situation. This also shows a significant advantage over CN1257671A, not including the value generated by improving leaf structure after the implementation of this invention. The method provided by this invention has significant practical value.

[0165] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A threshing and winnowing process of double return flow mode, the double return flow mode including flag return flow and leaf return flow, applied to the end of the threshing and winnowing process, six devices at the end of the threshing and winnowing process participating in the circulation process of the double return flow mode. The end six devices include: The second last threshing machine, the fourth last wind separator, the third last wind separator, the first last threshing machine, the second last wind separator and the first last wind separator; characterized in that, When the layout order of the end six devices is: the second last threshing machine → the fourth last separator → the third last wind separator → the second last wind separator → the first last wind separator → the first last threshing machine, the backflow mode is: Backflow mode one: the material after the first last threshing machine threshes, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the third last wind separator; or Backflow mode two: the material after the first last threshing machine threshes, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the fourth last wind separator; or Backflow mode three: the material after the first last threshing machine threshes, backflows to the third last wind separator, the second last wind separator air selects pure leaves, backflows to the third last wind separator; When the layout order of the end six devices is: the second last threshing machine → the fourth last wind separator → the third last wind separator → the first last threshing machine → the second last wind separator → the first last wind separator, the backflow mode is: Backflow mode four: the material after the first last wind separator air selection, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the third last wind separator; or Backflow mode five: the material after the first last wind separator air selection, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the fourth last wind separator; or Backflow mode six: the material after the first last wind separator air selection, backflows to the second last threshing machine, the second last wind separator air selects pure leaves, backflows to the third last wind separator; or Backflow mode seven: the material after the first last wind separator air selection, backflows to the second last threshing machine, the second last wind separator air selects pure leaves, backflows to the fourth last wind separator; When the layout order of the end six devices is: the second last threshing machine → the fourth last wind separator → the third last wind separator → the second last wind separator → the first last threshing machine → the first last wind separator, the backflow mode is: Backflow mode eight: the material after the first last wind separator air selection, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the third last wind separator; or Backflow mode nine: the material after the first last wind separator air selection, backflows to the third last wind separator, the second last wind separator air selects pure leaves, backflows to the third last wind separator; or Backflow mode ten: the material after the first last wind separator air selection, backflows to the fourth last wind separator, the second last wind separator air selects pure leaves, backflows to the fourth last wind separator; The threshing and winnowing process of the double backflow mode also includes a process optimization step, and the process optimization step includes: Step S1: setting device preliminary operation parameters, the device runs with the preliminary operation parameters, wherein the end six devices run in the flow order of the double backflow mode; Step S2: in the normal operation state of the equipment, process parameters of the last six equipments are measured; the process parameters include: winnowing efficiency, reflux efficiency, leaf tearing rate, incoming material leaf content, pure tobacco output, and leaf structure; Step S31: data fitting is performed according to the process parameters of the last six equipments in the flow, and a total efficiency calculation formula of the flow winnowing is obtained; Step S32: according to the corresponding relationship between the first leaf threshing drum speed and the effective tearing rate, the data statistical software is used for fitting, and a fitting equation between the first leaf threshing drum speed and the effective tearing rate is obtained; Step S41: the third-to-last wind separator efficiency W3 and the fourth-to-last wind separator efficiency W4 are measured; Step S42: the first-to-last leaf threshing machine tearing rate Y1 is measured; Step S43: the maximum leaf reflux efficiency Hleaf and the maximum flag reflux efficiency Hflag are determined; Step S51: according to the third-to-last wind separator efficiency W3, the fourth-to-last wind separator efficiency W4, the maximum leaf reflux efficiency Hleaf, the maximum flag reflux efficiency Hflag, and the total efficiency calculation formula of the flow winnowing, the optimal leaf reflux efficiency Hleaf and the optimal flag reflux efficiency Hflag are determined; Step S52: the measured first-to-last leaf threshing machine tearing rate Y1 is substituted into the fitting equation between the first-to-last leaf threshing machine drum speed and the effective tearing rate, and the optimal first-to-last leaf threshing machine drum speed is obtained; Step S6: the optimal leaf reflux efficiency Hleaf, the optimal flag reflux efficiency Hflag, and the optimal first-to-last leaf threshing machine drum speed are reset in the equipment for operation; The step S51 comprises: The third-to-last wind separator efficiency W3, the fourth-to-last wind separator efficiency W4, and the first-to-last leaf threshing machine tearing rate Y1 are substituted into the total efficiency calculation formula of the flow winnowing, and the leaf reflux efficiency Hleaf and the flag reflux efficiency Hflag are respectively started from 1% and are substituted into the total efficiency calculation formula of the flow winnowing by the recursive method with each 1% as a gradient until the leaf reflux efficiency Hleaf and the flag reflux efficiency Hflag are recursively maximized, so that the optimal leaf reflux efficiency Hleaf and the optimal flag reflux efficiency Hflag are determined; In the step S32, the last-1 threshing drum rotation speed x and the effective tearing rate The fitting equation between and is: .

2. The double return flow pattern threshing process according to claim 1, wherein, The step S41 comprises: The wind volume of the leaf winnower is adjusted, and the third-to-last wind separator efficiency W3 and the fourth-to-last wind separator efficiency W4 are measured under the condition that the leaf stem is 1.0%.

3. The double return flow pattern threshing process according to claim 1, wherein, The step S42 comprises: The first-to-last leaf threshing machine drum speed is adjusted, and the first-to-last leaf threshing machine tearing rate Y1 is measured by taking the average value in the range of the loss rate: tearing rate 1:6~1:

8.

4. The double return flow model of threshing and separating process according to claim 1, characterized in that, The step S43 comprises: The flag reflux flow and the leaf reflux flow are adjusted to meet the condition that the actual flow of the fourth-to-last winnower, the third-to-last winnower, the second-to-last winnower, the first-to-last winnower, and the first-to-last leaf threshing machine is not greater than the rated flow and is close to the rated flow, and the maximum leaf reflux efficiency Hleaf and the maximum flag reflux efficiency Hflag are determined.

5. The double return flow model of threshing and separating process according to claim 1, characterized in that, When the reflux mode is the first reflux mode, the total efficiency calculation formula of the flow winnowing Wtotal is: ； When the reflux mode is the second reflux mode, the total efficiency calculation formula of the flow winnowing Wtotal is: ； Wherein, Y2 is the second-to-last leaf threshing machine tearing efficiency measured value. When the backflow mode is backflow mode three, the total efficiency of the process winnowing Wtotal is calculated by the following formula: 。 6. The double return flow model of threshing and separating process according to claim 1, characterized in that, When the backflow mode is backflow mode four, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； When the backflow mode is backflow mode five, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； When the backflow mode is backflow mode six, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； When the backflow mode is backflow mode seven, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； Wherein, Y2 is the penultimate threshing machine tearing efficiency measured value.

7. The double return flow model of threshing and separating process according to claim 1, characterized in that, When the backflow mode is backflow mode eight, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； Wherein, Y2 is the penultimate threshing machine tearing efficiency measured value. When the backflow mode is backflow mode nine, the total efficiency of the process winnowing Wtotal is calculated by the following formula: ； When the backflow mode is backflow mode ten, the total efficiency of the process winnowing Wtotal is calculated by the following formula: 。

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