A method for regulating the combustion performance of reconstituted tobacco by displacement electrodialysis device

Abstract

The application discloses a method for regulating the combustion performance of reconstituted tobacco leaves by replacing an electrodialysis device. The method realizes selective removal of chlorine ions in tobacco extract liquid by replacing the electrodialysis device, while retaining the effective positive ion potassium ions, thereby promoting the combustion and pyrolysis of reconstituted tobacco leaves. The papermaking reconstituted tobacco leaves prepared by using the processed tobacco extract liquid have significantly improved combustion and pyrolysis performance and effectively improved sensory quality.

Description

TECHNICAL FIELD

[0001] The application relates to a method for regulating the combustion performance of reconstituted tobacco leaves. BACKGROUND

[0002] Reconstituted tobacco leaves are homogeneous tobaccos with controllable quality, and controllability is the main feature of the papermaking process of reconstituted tobacco leaves. Tobacco extract is the core basis of the quality of the papermaking process of reconstituted tobacco leaves and has a significant impact on the quality of reconstituted tobacco leaves. With the increasing maturity of membrane technology, membrane technology, especially microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO) and electrodialysis (ED), is favored by researchers. Patent CN104305518A reports a membrane extraction process for tobacco extract. Patent CN107137971A also reports a membrane separation process for tobacco extract. Patent CN206051789U develops a system for extracting nicotine from tobacco stem and leaf wastewater by membrane integration technology.

[0003] Tobacco extract contains a large amount of charged components, such as potassium, sodium, calcium, magnesium, chloride, nitrate and other inorganic ions, as well as amino acids and nicotine. These charged components affect the quality of reconstituted tobacco leaves. Chloride ions, as one of the most important inorganic elements in tobacco, are considered to be a flame retardant factor that affects the moisture absorption and combustion of tobacco. Studies have shown that when the chlorine content of tobacco leaves is less than 1.0%, the combustion performance is good, and when the chlorine content exceeds 2%, it will cause serious extinguishing. Potassium ions are often used as a combustion-supporting agent that can promote the combustion of tobacco and reduce the tar in smoke. Therefore, regulating the charged components in tobacco extract is an important method to improve the quality of tobacco. Patent CN105481152A reports a method for continuously removing chlorine and nitrate from tobacco extract. Although this method can remove chlorine and nitrate from the extract, a large amount of potassium ions in the extract are lost, reducing the quality of the tobacco leaves. Although potassium can be supplemented externally, the introduction of exogenous chemicals cannot eliminate the influence of flame-retardant ions such as chloride ions in the matrix, and the addition amount is large, which can easily lead to a decrease in the sensory quality of cigarettes.

[0004] Displacement electrodialysis is a new type of electrodialysis system. By selecting membranes with specific separation functions and changing the arrangement of the membranes, selective removal and retention of specific ions in the material can be achieved. Currently, there is no report on using displacement electrodialysis technology to regulate the charged components of tobacco extract and the combustion and pyrolysis performance of reconstituted tobacco leaves. SUMMARY

[0005] In order to overcome the defects of the prior art, the application designs a novel displacement electrodialysis device, which is used for regulating the ion components of tobacco extract and the combustion pyrolysis performance of reconstituted tobacco, aims to selectively regulate the combustion-related anions in the tobacco extract, while retaining the original combustion-supporting effective component-potassium ions, so as to regulate the combustion pyrolysis performance of the reconstituted tobacco and improve the quality of the reconstituted tobacco.

[0006] In order to achieve the above-mentioned application purposes, the application adopts the following technical solutions:

[0007] The application discloses a method for regulating the combustion performance of reconstituted tobacco through a displacement electrodialysis device, which is characterized in that: the selective removal of chloride ions in the tobacco extract is realized through the displacement electrodialysis device, while the effective component-potassium ions with positive charges are retained, thereby promoting the combustion pyrolysis of the reconstituted tobacco.

[0008] Further, the arrangement mode of the membrane stack in the displacement electrodialysis device is cathode plate-cathode chamber-[cation exchange membrane-dilution chamber-anion exchange membrane-displacement chamber-anion exchange membrane-concentration chamber]n-cation exchange membrane-anode chamber-anode plate, the number n of the repeating units is 1-1000, and the materials of the anode plate and the cathode plate of the displacement electrodialysis device are corrosion-resistant titanium coated with ruthenium.

[0009] Further, the method of the application is performed in the following manner: in the membrane stack of the displacement electrodialysis device, the tobacco extract is introduced into the displacement chamber, the potassium salt solution of organic acid is introduced into the dilution chamber, the salt solution or deionized water is introduced into the concentration chamber, and the strong electrolyte solution is introduced into the anode chamber and the cathode chamber; under the action of the direct current electric field, the cations in the anode chamber migrate to the concentration chamber through the cation exchange membrane, the chloride ions in the displacement chamber migrate to the concentration chamber through the anion exchange membrane, and at the same time, the organic acid root ions in the dilution chamber migrate to the displacement chamber through the anion exchange membrane to supplement the chloride ions removed from the displacement chamber, and the cations K + migrate to the cathode chamber.

[0010] Further, the potassium salt solution of organic acid introduced into the dilution chamber is at least one of a potassium malate solution, a potassium lactate solution, a potassium acetate solution, a potassium gluconate solution or a potassium citrate solution, and the concentration is 0.03-1.0 mol / L. Preferably, the potassium malate solution or the potassium gluconate solution.

[0011] Further, the anode chamber and the cathode chamber in the membrane stack of the displacement electrodialysis device are connected in series, so that the total amount of cations in the anode liquid and the cathode liquid remains unchanged, and the normal operation of the membrane stack is maintained.

[0012] Furthermore, the strong electrolyte solution introduced into the anode and cathode chambers is a sodium sulfate solution, potassium sulfate solution, sodium nitrate solution, or potassium nitrate solution with a concentration of 0.01-1.0 mol / L.

[0013] Furthermore, during the operation of the membrane stack of the displacement electrodialysis device, the feed solution in each compartment is first circulated by a peristaltic pump for 5-30 minutes to remove air bubbles from the membrane stack. During operation, the linear flow velocity of the solution in each compartment is controlled at 1-10 cm / s by the peristaltic pump to avoid concentration polarization. During operation, constant voltage or constant current operation can be used, with constant current operation preferred, and a current density of 5-30 mA / cm². 2 .

[0014] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0015] This invention utilizes a novel displacement electrodialysis device. By setting the arrangement of the membrane stacks, the ions in the tobacco extract can be regulated. That is, while selectively removing chloride ions from the tobacco extract, the content of its positively charged effective component (potassium ions) remains unchanged. This enables the regulation of the combustion pyrolysis performance of reconstituted tobacco leaves and enhances the compatibility between reconstituted tobacco leaves and cigarette combustion. Attached Figure Description

[0016] Figure 1 A schematic diagram of the membrane stack assembly of a replacement electrodialysis unit and a schematic diagram of its principle for regulating the combustion performance of reconstituted tobacco leaves.

[0017] Figure 2 The thermogravimetric curves (TG curves) of each reconstituted tobacco leaf sample in Example 1.

[0018] Figure 3 The differential thermogravimetric curves (DTG) of each reconstituted tobacco leaf sample in Example 1 are shown. Detailed Implementation

[0019] The following examples further illustrate the application of the novel displacement electrodialysis device in the regulation of combustion performance of reconstituted tobacco.

[0020] Example 1

[0021] This embodiment utilizes Figure 1 The displacement electrodialysis apparatus shown is used to treat tobacco extract. The membrane stack in the apparatus consists of two cation exchange membranes and two anion exchange membranes, along with a flow channel mesh and sealing gaskets. The two anion membranes are sandwiched between the two cation exchange membranes to achieve selective anion exchange. The effective area of ​​a single membrane is 189 cm². 2An anode chamber is formed between the anode plate and the adjacent cation exchange membrane, and a cathode chamber is formed between the cathode plate and the adjacent cation exchange membrane. A concentration chamber is formed between the two anion and cation exchange membranes closest to the anode chamber, a desalination chamber is formed between the two anion and cation exchange membranes closest to the cathode chamber, and a displacement chamber is formed between the two anion exchange membranes. The anode plate and cathode plate are connected to the positive and negative terminals of the power supply, respectively. The anode chamber and cathode chamber are connected in series to the electrode solution storage tank. The anion and cation exchange membranes used in the membrane stack are CJMA-3 and CJMC-3, respectively, provided by Hefei Kejia Polymer Materials Technology Co., Ltd.

[0022] The tobacco extract was added to the storage tank, and a peristaltic pump was used to circulate the extract between the displacement chamber and the storage tank. A 0.3 mol / L potassium malate solution was used in the desalination chamber, while a 0.3 mol / L K₂SO₄ solution was used in the concentration and polarization chambers. The solutions in each chamber were circulated for 10 minutes before applying 1.89 A (10 mA / cm²). 2 (a constant current).

[0023] After 1 hour of experimentation, 2 mL of sample was taken from the storage tank. After 2 hours, the power supply and peristaltic pumps in each chamber were turned off, and another 2 mL sample was taken from the storage tank. Ion chromatography was used to analyze the chloride and potassium ion content before the experiment and after 1 and 2 hours of testing. The specific results are shown in Table 1. Table 1 shows that after 1 hour of electrodialysis, the chloride ion content in the test solution decreased from 12582 μg / L to 1170 μg / L, indicating a very significant chloride removal effect. At this time, the potassium ion content in the test solution remained at a high level. After 2 hours of electrodialysis, chloride ions were undetectable in the test solution, demonstrating that the novel displacement electrodialysis method has excellent performance in removing harmful chloride ions from tobacco extract.

[0024] Table 1. K in the replacement chamber after 1 h and 2 h of replacement electrodialysis treatment. + and Cl- ion concentration

[0025]

[0026] Using conventional electrodialysis with the same specifications of cation and anion exchange membranes as a control, the membrane stack configuration was: cathode plate - cathode chamber - [cation exchange membrane - desalination chamber - anion exchange membrane - concentration chamber - cation exchange membrane]n - anode chamber - anode plate, where n is the number of repeating units, n=2. Tobacco extract was passed through the desalination chamber, deionized water through the concentration chamber, and potassium sulfate solution through the anode and cathode chambers. The chloride and potassium ion contents after treatment at the same current density for the same time are shown in Table 2. Table 2 shows that after 1 hour of electrodialysis with the same specifications of conventional ion exchange membranes, chloride ions decreased significantly, but potassium ions also decreased significantly, with a reduction of 74%.

[0027] Table 2. K in the desalination chamber after 1 h and 2 h of conventional electrodialysis treatment. + and Cl - Ion concentration

[0028]

[0029] The control stock solution, the solution treated with ordinary ion-exchange membrane electrodialysis for 2 hours, and the solution treated with displacement electrodialysis for 2 hours were further concentrated to a solids content of 40%. Reconstituted tobacco samples were prepared using a simulated papermaking process. These samples were then shredded, rolled, and prepared into cigarette samples for combustion pyrolysis performance analysis. The TG and DTG curves for each sample during combustion pyrolysis are shown below. Figure 2 and Figure 3 .from Figure 2 and Figure 3 As can be seen, both replacement electrodialysis and ordinary electrodialysis alter the combustion pyrolysis process of reconstituted tobacco, but their effects on combustion pyrolysis performance show opposite trends. Specific combustion pyrolysis characteristic parameters are shown in Table 3, especially the thermal decomposition temperature (T). P2 ) and residual carbon combustion pyrolysis temperature (T P3 The significant shift towards the low-temperature region indicates that replacement electrodialysis imparts high-potassium and low-chlorine composition characteristics to reconstituted tobacco, promoting combustion pyrolysis. Sensory evaluation results also show that the combustion rate of reconstituted tobacco samples treated with replacement electrodialysis was higher than the control sample, and the aroma and taste were significantly improved compared to both the control and conventional electrodialysis-treated samples.

[0030] Table 3 Characteristic parameters of combustion pyrolysis of various reconstituted tobacco leaves

[0031]

[0032] Example 2

[0033] This embodiment uses the same displacement electrodialysis apparatus as in Example 1 to treat the tobacco extract. The anion and cation exchange membranes used in the membrane stack are AMX and CMX from ASTOM Corporation of Japan.

[0034] The tobacco extract was added to the storage tank, and a peristaltic pump was used to circulate the extract between the displacement chamber and the storage tank. A 0.3 mol / L potassium lactate solution was used in the desalination chamber, while a 0.3 mol / L K₂SO₄ solution was used in the concentration and polarization chambers. The solutions in each chamber were circulated for 10 minutes before applying 1.89 A (10 mA / cm²). 2 (a constant current).

[0035] After 1 hour of experimentation, 2 mL of sample was taken from the storage tank. After 2 hours, the power supply and peristaltic pumps in each chamber were turned off, and another 2 mL sample was taken from the storage tank. Ion chromatography was used to analyze the chloride and potassium ion contents before the experiment and after 1 and 2 hours of testing. The specific results are shown in Table 4. Table 4 shows that after 1 hour of electrodialysis, the chloride ion content in the test solution decreased from 12572 μg / L to 0 μg / L, indicating a very significant chloride removal effect. At this point, the potassium ion content in the test solution not only did not decrease but actually increased, which will be more beneficial for the subsequent processing of the tobacco extract.

[0036] Table 4. K in the replacement chamber after 1 h and 2 h of replacement electrodialysis treatment. + and Cl- ion concentration

[0037]

[0038] Using conventional electrodialysis with the same cation and anion exchange membranes as a control, the membrane stack configuration was: cathode plate-cathode chamber-[cation exchange membrane-desalination chamber-anion exchange membrane-concentration chamber-cation exchange membrane]n-anode chamber-anode plate, where n is the number of repeating units, n=2. Tobacco extract was passed through the desalination chamber, deionized water through the concentration chamber, and potassium sulfate solution through the anode and cathode chambers. The chloride and potassium ion contents after treatment at the same current density for the same time are shown in Table 5. Table 5 shows that after 1 hour of conventional electrodialysis treatment of the tobacco extract using ASTOM's cation and anion exchange membranes, chloride ions were almost completely removed, but potassium ions were also significantly reduced, with a decrease of over 54%.

[0039] Table 5. K in the desalination chamber after 1 h and 2 h of conventional electrodialysis treatment. + and Cl- ion concentration

[0040]

[0041] The control stock solution, the solution treated with ordinary ion-exchange membrane electrodialysis for 2 hours, and the solution treated with displacement electrodialysis for 2 hours were further concentrated to a solids content of 40%. Reconstituted tobacco samples were prepared using a simulated papermaking process. These samples were then shredded, rolled, and prepared into cigarette samples for combustion pyrolysis performance analysis. Specific combustion pyrolysis characteristic parameters for each sample are shown in Table 6, especially the thermal decomposition temperature (T). P2 ) and residual carbon combustion pyrolysis temperature (T P3 The significant shift towards the low-temperature region indicates that replacement electrodialysis imparts high-potassium and low-chlorine composition characteristics to reconstituted tobacco, promoting combustion pyrolysis. Sensory evaluation results also show that the combustion rate of reconstituted tobacco treated with replacement electrodialysis was higher than the control sample, and the taste was significantly improved and the irritation reduced compared to the control and conventional electrodialysis treated samples.

[0042] Table 6 Characteristic parameters of pyrolysis from reconstituted tobacco combustion

[0043]

[0044]

[0045] The above description is merely an example of how the present invention uses the electrodialysis system to replace chloride ions with sulfate ions, 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 should be included within the scope of protection of the present invention.

Claims

1. A method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device, characterized in that: The selective removal of chloride ions from tobacco extract is achieved by using a displacement electrodialysis device, while retaining the positively charged effective component potassium ions, thereby promoting the combustion pyrolysis of reconstituted tobacco leaves. The membrane stack in the displacement electrodialysis device is arranged as follows: cathode plate - cathode chamber - [cation exchange membrane - desalination chamber - anion exchange membrane - displacement chamber - anion exchange membrane - concentration chamber] n - cation exchange membrane - anode chamber - anode plate, where n is the number of repeating units; In the membrane stack of a displacement electrodialysis device, tobacco extract is introduced into the displacement chamber, an organic acid potassium salt solution is introduced into the desalination chamber, a salt solution or deionized water is introduced into the concentration chamber, and a strong electrolyte solution is introduced into the anode and cathode chambers. Under the action of a DC electric field, cations in the anode chamber migrate through the cation exchange membrane to the concentration chamber, and chloride ions in the displacement chamber migrate through the anion exchange membrane to the concentration chamber. Simultaneously, organic acid anions in the desalination chamber migrate through the anion exchange membrane to the displacement chamber to replenish the chloride ions that have migrated into the displacement chamber. The potassium ions in the desalination chamber... + It migrates to the cathode chamber.

2. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: n is 1-1000.

3. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: The anode and cathode plates of the displacement electrodialysis device are made of titanium coated with ruthenium; the compartments between adjacent ion exchange membranes are all made of gaskets with flow channels and grids.

4. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: The organic acid potassium salt solution introduced into the desalination chamber is at least one of potassium malate, potassium lactate, potassium acetate, potassium gluconate, or potassium citrate solution, with a concentration of 0.03-1.0 mol / L.

5. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: The anode and cathode chambers in the membrane stack of the displacement electrodialysis device are connected in series, thereby ensuring that the total amount of cations in the anolyte and catholyte remains constant and maintaining the normal operation of the membrane stack.

6. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: The strong electrolyte solution introduced into the anode and cathode chambers is a sodium sulfate solution, potassium sulfate solution, sodium nitrate solution, or potassium nitrate solution with a concentration of 0.01-1.0 mol / L.

7. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: When the membrane stack of the displacement electrodialysis device is running, the feed solution in each compartment is first circulated by a peristaltic pump for 5-30 minutes to remove air bubbles from the membrane stack. During operation, the linear flow rate of the solution in each compartment is controlled by the peristaltic pump to be 1-10 cm / s to avoid concentration polarization.

8. The method for regulating the combustion performance of reconstituted tobacco leaves using a displacement electrodialysis device according to claim 1, characterized in that: The membrane stack of the displacement electrodialysis device operates under constant current, with a current density of 5-30 mA / cm². 2 .

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