A method for characterizing the processing strength of a two-stage tobacco leaf air separator

Abstract

The application discloses a kind of processing intensity characterization methods of two-stage leaf air separator, is based on the three main objects of heat and mass transfer in two-stage leaf air separation process leaf, circulating gas and dust removal gas analysis, using the proportion of dust removal air volume and circulating air volume in two-stage leaf air separation process to characterize the volatilization amount of low-boiling-point component in leaf, while using the moisture saturation of circulating gas, i.e. moisture content, to control the speed of moisture mass transfer, from the total amount and speed of leaf and circulating gas mass transfer in two-stage leaf air separation process to characterize the processing intensity of two-stage leaf air separator. The application uses quantitative method to characterize the processing intensity in leaf air separation process, according to the quality characteristics and consumption demand of flue-cured tobacco type cigarette products, selects different processing intensity of two-stage leaf air separator, effectively guides cigarette processing technology.

Description

Technical Field

[0001] The invention relates to the field of cigarette shred processing, in particular to a method for characterizing the processing strength of a two-stage air separator for shredded tobacco. Background Art

[0002] The purity of cut tobacco is a constant pursuit in the tobacco industry. Spectral impurity removal, metal detection, screening, and air separation are widely used in tobacco cut tobacco production. Two-stage air separation of cut tobacco leaves has two fundamental functions: first, cooling and shaping the dried cut tobacco leaves to improve their filling properties; second, removing light debris (such as feathers) and heavy debris (such as stems and scale).

[0003] In the tobacco industry, two-stage air separation and pneumatic conveying of cut tobacco leaves are widely used in cigarette processing. Gas is used as a carrier and heat medium to transport and dry the material in pipes, with the gas flow directly providing energy for material movement. However, excessive material movement speeds during these processes can lead to tobacco fragmentation, and uneven gas-solid phases can lead to uneven moisture content and stratification.

[0004] While two-stage air separation improves leaf filling performance and purifies leaves, it also has drawbacks such as leaf fragmentation and reduced sensory quality. As the material temperature decreases before and after the two-stage air separation, sensory quality indicators such as aroma, smoke sweetness, pungency, and mouth dryness decrease significantly.

[0005] Tobacco industry technicians have also explored technologies such as structural optimization of two-stage leaf separation equipment, improved control methods, leaf flow rate and air separation air volume, but no relevant reports have been found on the research on the processing intensity of the two-stage leaf separation process.

[0006] The research on characterizing the processing intensity during the two-stage winnowing process of leaf shreds is of positive significance for exploring the changing rules during the two-stage winnowing process of leaf shreds. Summary of the Invention

[0007] In order to overcome the shortcomings of the existing technology, the present invention provides a method for characterizing the processing strength of a two-stage air separation machine for leaf shreds, so as to accurately quantify the processing strength of the two-stage air separation machine for leaf shreds, thereby effectively guiding the cigarette processing technology and overcoming the problem that the processing strength of the two-stage air separation machine for leaf shreds cannot be quantified and characterized.

[0008] To achieve the purpose, the present invention adopts the following technical solutions:

[0009] The method for characterizing the processing strength of a two-stage wind separator for leaf shreds of the present invention is characterized in that it comprises the following steps:

[0010] Step 1: After adjusting the wind force balance of the two-stage air separator, a first measuring hole is provided on the horizontal section of the return air section of the circulating gas pipeline of the two-stage air separator, and is used to measure the wind speed of the circulating gas in the horizontal section of the pipeline; a first detection point is provided near the first measuring hole, and a temperature sensor, a first differential pressure gauge, and a moisture content sensor are provided at the first detection point, which are used to respectively collect the temperature value T1, the differential pressure value ΔP1, and the moisture content H1 of the circulating gas in the horizontal section of the pipeline online;

[0011] Step 2: Calculate the density ρ1 of the circulating gas:

[0012] Step 2.1: Calculate the water vapor partial pressure p in the circulating gas according to formula (1): q :

[0013]

[0014] In formula (1): B is the standard atmospheric pressure value;

[0015] Step 2.2, calculate the density ρ1 of the circulating gas according to formula (2);

[0016]

[0017] Step 3: Calculate the velocity ν1 of the circulating gas according to formula (3);

[0018]

[0019] Step 4: Calculate the mass flow rate M1 of the circulating gas according to formula (4);

[0020]

[0021] In formula (4), D1 represents the diameter of the return air section of the circulating gas pipeline;

[0022] Step 5: A second measuring hole for dust removal gas is provided on the vertical section of the dust removal gas pipeline of the two-stage air separator for measuring the wind speed of the dust removal gas in the vertical section; a second detection point is provided near the second measuring hole, and a second differential pressure gauge is provided at the second detection point for online collecting the differential pressure value ΔP2 of the dust removal gas in the vertical section, wherein the temperature value T2 of the dust removal gas is the same as the temperature value T1 of the circulating gas, the moisture content H2 of the dust removal gas is the same as the moisture content H1 of the circulating gas, and the water vapor partial pressure p of the dust removal gas is the same as the water vapor partial pressure p of the circulating gas. q same;

[0023] Step 6: Calculate the dust removal gas velocity ν2 according to formula (5);

[0024]

[0025] Step 7: Calculate the mass flow rate M2 of the dust removal gas according to formula (6);

[0026]

[0027] In formula (6), D2 represents the diameter of the dust removal gas pipeline;

[0028] Step 8: Calculate the characterization index of the processing strength of the two-stage wind separator

[0029] The method for characterizing the processing strength of the two-stage air separator of the shredded leaves of the present invention is also characterized in that the moisture content sensor in step 1 is replaced by a relative humidity sensor of the circulating gas, which is used to collect the relative humidity RH1 of the circulating gas online, and then calculate the saturated water vapor partial pressure P of the circulating gas according to the temperature value T1 of the circulating gas using formula (7) s1 :

[0030]

[0031] In formula (7), EXP represents the natural exponential function;

[0032] Calculate the water vapor partial pressure p in the circulating gas according to formula (8): q1 ;

[0033] p q1 =p s1 ×RH1 (8)

[0034] The moisture content sensor of the dust removal gas in step 5 is replaced by a relative humidity sensor of the dust removal gas. The relative humidity RH2 of the dust removal gas is the same as the relative humidity RH1 of the circulating gas. The saturated water vapor partial pressure P of the dust removal gas is s2 The saturated water vapor partial pressure P of the circulating gas s1 Similarly, the water vapor partial pressure p of the dust removal gas q2 The water vapor partial pressure p of the circulating gas q1 same.

[0035] In step 1, the wind force balance of the two-stage air separator for shredded leaves is adjusted to a negative pressure of -5 to -0 μPa by adjusting the feed port of the two-stage air separator for shredded leaves.

[0036] The processing strength characterization index A is between 10% and 30%, and is proportional to the processing strength of the leaf shred two-stage air separator.

[0037] The electronic device of the present invention includes a memory and a processor, wherein the memory is used to store a program that supports the processor to execute the characterization method, and the processor is configured to execute the program stored in the memory.

[0038] The present invention provides a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program executes the steps of the characterization method when executed by a processor.

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

[0040] The present invention provides a method for characterizing the processing strength of a two-stage air separation machine for leaf shreds. The method uses a technical indicator to characterize the processing strength of the two-stage air separation process of leaf shreds. The indicator is related to the circulating gas flow rate and the dust removal gas flow rate in the two-stage air separation process of leaf shreds. The characterization is performed using the principles of conservation of material mass and conservation of heat in the two-stage air separation process of leaf shreds. The method is based on tobacco chemistry, according to Dalton's law of partial pressure, and utilizes the law of conservation of mass in the two-stage air separation process of leaf shreds. Based on the principle of volatilization of aroma components in the two-stage air separation process of leaf shreds, the properties of the three main objects of mass transfer in the two-stage air separation process of leaf shreds are analyzed: leaf shreds, circulating gas and dust removal gas. The leaf shreds are the source of mass transfer and heat transfer in the two-stage air separation process, and the circulating gas and dust removal gas are the carriers of mass transfer and heat transfer in the two-stage air separation process of leaf shreds. The smaller the dust removal gas mass flow rate M2 and the larger the circulating gas mass flow rate M1, the smaller the processing intensity A value, the higher the saturation of the circulating gas as the moisture carrier in the leaf silk, the lower the moisture loss rate of the leaf silk during the two-stage air separation process, and the vapor partial pressure of the volatile components in the leaf silk in the circulating gas can be increased, reducing the volatilization rate of the low-boiling point aroma components in the leaf silk during the two-stage air separation process, thereby reducing the loss of aroma components in the leaf silk. DETAILED DESCRIPTION

[0041] The present invention will be further described in detail below with reference to the examples, but the examples are not intended to limit the technical solutions of the present invention.

[0042] Unless otherwise specified, the professional terms involved are based on the 2016 edition of the Cigarette Processing Specifications compiled by the State Tobacco Monopoly Administration.

[0043] In this embodiment, a method for characterizing the processing strength of a two-stage air separator for leaf shreds is provided. The method is to characterize the processing strength of a two-stage air separator for leaf shreds. The method is to characterize the low-boiling-point components in the leaf shreds as the moisture in the leaf shreds evaporates during the air separation process and transfer them to the circulating gas. At the same time, the circulating gas carries the smoke dust in the leaf shreds through the gas-solid separation filter. In the return air duct, the smoke dust has a density greater than that of the circulating gas and is therefore mainly distributed in the middle and lower part of the return air duct. The dust removal duct arranged in the middle and lower part of the return air duct carries the smoke dust in the circulating gas out to the dust collector through the dust removal gas at a certain flow rate. However, when the smoke dust is discharged, the moisture and low-boiling-point components in the leaf shreds are also discharged at the same time, resulting in a problem of reduced flavor components in the leaf shreds after air separation. The method characterizes the volatilization amount of the low-boiling-point components in the leaf shreds by utilizing the ratio of the dust removal air volume to the circulating air volume during the two-stage air separation process of the leaf shreds. At the same time, the moisture saturation, i.e., the moisture content, of the circulating gas is utilized to control the moisture mass transfer rate. The method characterizes the processing strength of the two-stage air separator for leaf shreds from two aspects, namely, the total amount and rate of mass transfer between the leaf shreds and the circulating gas during the two-stage air separation process of the leaf shreds. Specifically, the method includes the following steps:

[0044] Step 1: After adjusting the wind force balance of the two-stage air separator, adjust the feed inlet of the two-stage air separator to a negative pressure of -5 to -0 μPa. A first measuring hole is provided on the horizontal section of the return air section of the circulating gas pipeline of the two-stage air separator, and is used to measure the wind speed of the circulating gas in the horizontal section of the pipeline. A first detection point is provided near the first measuring hole, and a temperature sensor, a first differential pressure gauge, and a moisture content sensor are provided at the first detection point, respectively, for online collection of the temperature value T1, differential pressure value ΔP1, and moisture content H1 of the circulating gas in the horizontal section of the pipeline.

[0045] Step 2: Calculate the density ρ1 of the circulating gas:

[0046] Step 2.1: Calculate the water vapor partial pressure p in the circulating gas according to formula (1): q :

[0047]

[0048] In formula (1), B is the standard atmospheric pressure value.

[0049] Step 2.2, calculate the density ρ1 of the circulating gas according to formula (2);

[0050]

[0051] Step 3: Calculate the velocity ν1 of the circulating gas according to formula (3);

[0052]

[0053] Step 4: Calculate the mass flow rate M1 of the circulating gas according to formula (4);

[0054]

[0055] In formula (4), D1 represents the diameter of the return air section of the circulating gas pipeline.

[0056] Step 5: A second measuring hole for dust removal gas is provided on the vertical section of the dust removal gas pipeline of the two-stage air separator for measuring the wind speed of the dust removal gas in the vertical section; a second detection point is provided near the second measuring hole, and a second differential pressure gauge is provided at the second detection point for online collecting the differential pressure value ΔP2 of the dust removal gas in the vertical section, wherein the temperature value T2 of the dust removal gas is the same as the temperature value T1 of the circulating gas, the moisture content H2 of the dust removal gas is the same as the moisture content H1 of the circulating gas, and the water vapor partial pressure p of the dust removal gas is the same as the water vapor partial pressure p of the circulating gas. q same.

[0057] Step 6: Calculate the dust removal gas velocity ν2 according to formula (5);

[0058]

[0059] Step 7: Calculate the mass flow rate M2 of the dust removal gas according to formula (6);

[0060]

[0061] In formula (6), D2 represents the diameter of the dust removal gas pipeline.

[0062] Step 8: Calculate the characterization index of the processing strength of the two-stage wind separator

[0063] The processing strength A value of the two-stage air separation machine for leaf shreds is between 10% and 30%. The intrinsic quality of the leaf shreds after the two-stage air separation is better. On the basis of basically maintaining the sensory quality characteristics of the leaf shreds after drying, it can reduce the irritation of the smoke to a certain extent by removing some low-boiling point components in the leaf shreds.

[0064] In the specific implementation, the moisture content sensor in step 1 is replaced by a relative humidity sensor of the circulating gas, which is used to collect the relative humidity RH1 of the circulating gas online, and then calculate the saturated water vapor partial pressure P of the circulating gas according to the temperature value T1 of the circulating gas using formula (7): s1 :

[0065]

[0066] In formula (7), EXP represents the natural exponential function.

[0067] Calculate the water vapor partial pressure p in the circulating gas according to formula (8): q1 ;

[0068] p q1=p s1 ×RH1 (8)

[0069] In this embodiment, the moisture content sensor of the dust removal gas in step 5 is replaced by a relative humidity sensor of the dust removal gas. The relative humidity RH2 of the dust removal gas is the same as the relative humidity RH1 of the circulating gas. The saturated water vapor partial pressure P of the dust removal gas is s2 The saturated water vapor partial pressure P of the circulating gas s1 Similarly, the water vapor partial pressure p of the dust removal gas q2 The water vapor partial pressure p of the circulating gas q1 same.

[0070] Example 1

[0071] Step 1: After drying, the moisture content of the Huangshan A brand thin plate entering the two-stage air separator is 12.94%. The material flow rate before the leaves enter the two-stage air separator is about 3380 kg / h. The moisture content of the leaves after the two-stage air separation is 12.41%.

[0072] Step 2: Adjust the wind force balance of the two-stage air separator so that the feed inlet is adjusted to a slight negative pressure of -5 to -0 μPa, and there is no positive pressure at the feed inlet. A circulating gas measurement hole is installed on the horizontal section of the return air section of the two-stage air separator's circulating gas pipeline, serving as a circulating gas wind speed detection point. A dust removal gas measurement hole is installed on the vertical section of the dust removal gas pipeline of the two-stage air separator, serving as a dust removal gas wind speed detection point. A dust removal gas differential pressure gauge is installed at the circulating detection point.

[0073] The diameter D1 of the measuring circulating gas pipeline is 600 mm; the pressure difference detection value △P1 of the online differential pressure gauge is 104.3 Pa; the temperature T=36.2°C at the circulating gas wind speed detection point is collected using a temperature sensor.

[0074] The diameter D2 of the dust removal gas pipeline is 300mm; the pressure difference detection value △P2 of the online differential pressure gauge is 20.3Pa.

[0075] Step 3: The relative humidity RH1 of the circulating gas collected online is 45.85%, as follows:

[0076] First, the gas density ρ1 is calculated to be 1.1280 kg / m by using the relative humidity RH1 and temperature T1 of the circulating gas according to equations (7), (8) and (2). 3 ;

[0077] Step 4: The velocity ν1 of the circulating gas is calculated as 13.62 m / s according to formula (4) using the pressure difference detection value △P1 of the circulating gas online differential pressure gauge and the gas density ρ1.

[0078] Step 5: Calculate the circulating gas mass flow rate M1 according to formula (4) to be 15640 kg / h.

[0079] Step 6: The velocity ν1 of the circulating gas is calculated to be 6.0 m / s according to formula (5) using the pressure difference detection value △P2 of the dust removal gas online differential pressure gauge and the dust removal gas density ρ2.

[0080] Step 7: Calculate the dust removal gas mass flow rate M2 according to formula (6) to be 1722.5 kg / h;

[0081] Step 8: Calculate the characteristic index A of the burley tobacco roasting machine processing strength to be 11.0%.

[0082] After the Huangshan A brand thin plate is dried, the leaf shreds pass through the two-stage air separation with the above-mentioned process parameter combination. Due to the reasonable design of the dust removal gas mass flow rate, the leaf shreds run smoothly in the two-stage air separation equipment, the leaf shreds are small in size, the smoke dust is removed unobstructed, and there is no smoke dust residue in the dust removal pipeline.

[0083] From the comparative evaluation and analysis of the sensory quality of the leaf shreds before and after the two-stage air separation, the leaf shreds after the two-stage air separation using the above-mentioned process parameter combination have a good sweetness of the smoke, a slightly improved aroma texture, less loss of aroma, and a slightly increased smoke concentration. Overall, the sensory quality of the leaf shreds after the two-stage air separation is maintained well.

[0084] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for characterizing the processing strength of a two-stage wind separator for leaf shreds, characterized in that: The steps include: Step 1: After adjusting the wind force balance of the two-stage air separator, a first measuring hole is set on the horizontal section of the return air section of the circulating gas pipeline of the two-stage air separator, and is used to measure the wind speed of the circulating gas in the horizontal section of the pipeline; a first detection point is set near the first measuring hole, and a temperature sensor, a first differential pressure gauge and a moisture content sensor are set at the first detection point, which are used to collect the temperature value T1 and differential pressure value of the circulating gas in the horizontal section of the pipeline online respectively. and moisture content H1; Step 2: Calculate the density of the circulating gas 1: Step 2.1: Calculate the water vapor partial pressure in the circulating gas according to formula (1): : (1) In formula (1): B is the standard atmospheric pressure value; Step 2.2: Calculate the density of the circulating gas according to formula (2): ; (2) Step 3: Calculate the circulating gas velocity according to formula (3): ; (3) Step 4: Calculate the mass flow rate M1 of the circulating gas according to formula (4); (4) In formula (4), D1 represents the diameter of the return air section of the circulating gas pipeline; Step 5: A second measuring hole for dust removal gas is provided on the vertical section of the dust removal gas pipeline of the two-stage air separator for leaf shreds, and is used to measure the wind speed of the dust removal gas in the vertical section of the pipeline; a second detection point is provided near the second measuring hole, and a temperature sensor, a second differential pressure gauge and a moisture content sensor are provided at the second detection point, which are used to collect the temperature value T2 and the differential pressure value T2 of the dust removal gas in the vertical section of the pipeline online respectively. and moisture content H2, wherein the temperature value T2 of the dust removal gas is the same as the temperature value T1 of the circulating gas, the moisture content H2 of the dust removal gas is the same as the moisture content H1 of the circulating gas, and the water vapor partial pressure of the dust removal gas is the same as the water vapor partial pressure of the circulating gas. same; Step 6: Calculate the dust removal gas velocity according to formula (5) ; (5) Step 7: Calculate the mass flow rate M2 of the dust removal gas according to formula (6); (6) In formula (6), D2 represents the diameter of the dust removal gas pipeline; Step 8: Calculate the characterization index of the processing strength of the two-stage wind separator .

2. The method for characterizing the processing strength of the two-stage wind separator for leaf shreds according to claim 1, characterized in that: The moisture content sensor in step 1 is replaced by a relative humidity sensor of the circulating gas, which is used to collect the relative humidity RH1 of the circulating gas online, and then calculate the saturated water vapor partial pressure of the circulating gas according to the temperature value T1 of the circulating gas using formula (7): : (7) In formula (7), represents the natural exponential function; Calculate the water vapor partial pressure in the circulating gas according to formula (8): ; (8)。 3. The method for characterizing the processing strength of the two-stage wind separator of leaf shreds according to claim 2, characterized in that: The moisture content sensor of the dust removal gas in step 5 is replaced by a relative humidity sensor of the dust removal gas. The relative humidity RH2 of the dust removal gas is the same as the relative humidity RH1 of the circulating gas. The saturated water vapor partial pressure of the dust removal gas is Saturated water vapor partial pressure of the circulating gas The same, the water vapor partial pressure of the dust removal gas Water vapor partial pressure of the circulating gas same.

4. The method for characterizing the processing strength of the two-stage wind separator for leaf shreds according to claim 1, characterized in that: In step 1, the adjustment of the wind force balance of the two-stage leaf shreds air separator is to adjust the feed port of the two-stage leaf shreds air separator to a negative pressure of -5 to -0 μPa.

5. The method for characterizing the processing strength of the two-stage wind separator for leaf shreds according to claim 1, characterized in that: The characterization index A is between 10% and 30%, and is proportional to the processing intensity of the two-stage wind separator for leaf shreds.

6. An electronic device comprising a memory and a processor, characterized in that: The memory is used to store a program that supports a processor to execute the characterization method according to any one of claims 1 to 5, and the processor is configured to execute the program stored in the memory.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the characterization method according to any one of claims 1 to 5 are executed.

Images