A method for recovering high nicotine flavor materials from reconstituted tobacco leaf white water

Abstract

The present application belongs to the technical field of reconstituted tobacco production and processing, and particularly relates to a method for recovering high-nicotine flavoring substances from white water of reconstituted tobacco. The method first purifies the white water of the papermaking process through multiple stages to obtain clear white water, and then uses a macroporous resin filler that selectively enriches nicotine in wastewater to perform column adsorption in a gradient flow rate manner to achieve recovery of high-nicotine substances. After adsorption is completed, a specific process is used to elute and concentrate the elution solvent to obtain a high-nicotine flavoring substance. The method of the present application can ensure the continuous operation of membrane purification white water, increase the amount of white water treated, shorten the treatment time, effectively increase the proportion of nicotine in the recovered substance, reduce the content of nornicotine and anatabine in the recovered solution, and reduce the pigment content in the recovered liquid, thereby reducing the negative impact of the recovered substance on cigarette products in the subsequent application process.

Description

Technical Field

[0001] This invention belongs to the field of reconstituted tobacco production technology, specifically relating to a method for recovering high-nicotine aroma substances from the white water of reconstituted tobacco. Background Technology

[0002] Reconstituted tobacco, also known as tobacco sheet, is a homogenized tobacco leaf produced from tobacco dust, stems, and broken tobacco leaves through processes such as extraction, concentration, pulping, papermaking, coating, and drying. Because it employs a papermaking forming technology similar to that used in traditional papermaking, the production process generates a large amount of wastewater. This wastewater primarily originates from the papermaking process. The pulp (approximately 1% concentration) is dewatered on the wire section, and most of the water and fine solids pass through the forming wire, resulting in a milky-white suspension known as white water. The main volatile component in white water is nicotine, along with small amounts of other alkaloids such as nornicotine and neonicotinoids. Recovering these alkaloids from the white water not only increases the added value of reconstituted tobacco production but also reduces the burden of wastewater treatment in subsequent stages of production. Tobacco alkaloids include nicotine, nornicotine, pseudoequiline, and neonicotine, and their composition and content directly affect the sensory evaluation quality of tobacco products. Among them, nicotine is crucial for improving the strength and aroma of cigarettes, while nornicotine, neonicotine, pseudoequiline, and other tobacco alkaloids have a negative impact on the sensory quality of cigarettes. Therefore, increasing the proportion of nicotine in the white water recovery material plays an important role in improving the sensory quality of the recovery solution.

[0003] Chinese Patent CN113498875B discloses a method and application for recovering aroma compounds from the concentrated white water of reconstituted tobacco leaves. The method involves first purifying the concentrated white water using a ceramic membrane, then adsorbing the aroma compounds in the water using a series of weakly polar and moderately polar resin fillers, and finally eluting with ethanol to obtain the enriched components. This method can recover the aroma compounds from the white water of reconstituted tobacco leaves.

[0004] However, because white water contains a large amount of impurities such as fine fibers, fillers, and proteins, directly using membrane purification equipment to remove these fine suspended solids will cause a rapid drop in membrane flux during operation. Although the membrane flux can recover to its initial level after chemical washing, frequent rinsing will directly affect the continuity and stability of its use. Since different types of resins have different adsorption degrees for aroma-producing components in white water, the method in this patent, which uses weakly polar resin and moderately polar resin in series to adsorb aroma-producing substances, results in a smaller amount of components enriched per unit mass of resin and a lower volume of white water treated in order to recover the tobacco-derived substances in the white water as fully as possible. Furthermore, alkaloids in tobacco that are detrimental to sensory effects, such as nicotine and neonicotinoids, are also recovered, and the recovered solution contains a high amount of pigment. In subsequent applications, the recovered solution will have a certain negative impact on the sensory and appearance quality of cigarettes or reconstituted tobacco products.

[0005] Therefore, it is necessary to optimize the method for recovering aroma substances from reconstituted tobacco white water in order to improve the separation degree of different substances and the recovery effect. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for recovering high-nicotine flavor substances from recycled tobacco white water. This method ensures the continuity of membrane purification white water operation, increases the amount of white water processed, shortens the processing time, effectively increases the proportion of nicotine in the recovered substances, reduces the content of nornicotine and neonicotinoids in the recovered solution, and reduces the pigment content in the recovered liquid, thereby reducing the negative impact of the recovered substances on cigarette products in subsequent applications.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for recovering high-nicotine aroma compounds from reconstituted tobacco white water includes the following steps:

[0009] 1) Collect, filter, centrifuge, and purify the white water generated during the papermaking process in the production of reconstituted tobacco to obtain clear white water;

[0010] 2) The purified clear water was adsorbed using a resin-filled chromatography column, with a gradient flow rate from high to low.

[0011] 3) After adsorption is complete, rinse the residual solution in the chromatography column with no less than 2 column volumes of distilled water or tap water at a certain flow rate;

[0012] 4) After cleaning, use an elution solvent to elute. Stop elution when more than 95% of the components in the effluent are the elution solvent by volume, and let it stand for 20 to 60 minutes.

[0013] 5) After elution, add distilled water to the eluent at a volume not exceeding 10% of its volume, and then remove the organic solvent from the eluent by one or more combinations of nitrogen blowing, rotary evaporation or distillation to obtain the target solution.

[0014] Preferably, the specific steps of collection, filtration, centrifugation, and purification in step 1) are as follows:

[0015] The white water generated during the papermaking process in the reconstituted tobacco production is collected, filtered, and the filtered white water and filter residue are obtained. ;

[0016] The filtered white water was centrifuged to obtain centrifuged white water and filter residue. ;

[0017] The centrifuged white water is then subjected to deep purification via ultrafiltration membrane to obtain clear white water and sludge.

[0018] Furthermore, in step 1), during purification, an ultrafiltration membrane is used to purify the white water after centrifugation; the ultrafiltration membrane used is a ceramic ultrafiltration membrane with a pore size of no more than 50 nm and an operating pressure of 0.1 MPa to 0.2 MPa.

[0019] Furthermore, in step 2), the resin type is preferably the weakly polar macroporous adsorption resin LS169A or LS200 produced by Blue Deep Special Resin Co., Ltd.

[0020] Furthermore, in step 2), the specific gradient adsorption process parameters are as follows: the adsorption flow rate is initially set at 17~25 BV / h to start the sample flow. When the nicotine concentration in the effluent reaches 1.5%~2% of the initial nicotine mass concentration in the clear white water, the flow rate is switched to 12~16 BV / h. When the nicotine concentration in the effluent reaches 1%~1.5% of the initial nicotine mass concentration in the clear white water, the flow rate is switched to 5~10 BV / h. Adsorption is stopped when the nicotine concentration in the effluent reaches 10%~20% of the initial nicotine mass concentration in the clear white water.

[0021] Furthermore, in step 4), the flow rate of the elution solvent is not higher than 2 BV / h, and the amount of elution solvent used is 1.5 to 3 times the column volume.

[0022] Furthermore, in step 4), the elution solvent is preferably anhydrous acetone.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] This invention provides a simple, efficient, and high-volume method for recycling high-nicotine aroma substances. The resin used in the adsorption process is regenerable and reusable, reducing costs. The alkaloids recovered from the white water can be reused in production, improving the cleanliness of the recycled water and reducing both water consumption and wastewater discharge during production. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the method for recovering high-nicotine aroma substances from reconstituted tobacco white water according to the present invention;

[0026] Figure 2 These are the adsorption curves of nicotine, nornicotine, neonicotine, and pseudoequisetine during gradient adsorption on a resin chromatography column. Detailed Implementation

[0027] To facilitate understanding of the present invention, the invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0029] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0030] Example 1

[0031] A method for recovering high-nicotine aroma substances from reconstituted tobacco white water, the process flow of which is as follows: Figure 1 As shown, the specific steps are as follows:

[0032] 1) Collect the white water generated during the papermaking process in the production of reconstituted tobacco leaves. Filter the white water through an arc screen to obtain filtered white water and filter residue. The mass percentage of suspended solids in the white water decreased from 0.40% to 0.27% after filtration. The filter residue I mainly consisted of larger fibers from the press blanket and the web pulp that were lost with the white water.

[0033] 2) The filtered white water obtained in step 1) is centrifuged using a horizontal screw centrifuge to obtain centrifuged white water and filter residue. The mass percentage of suspended solids in the white water decreased from 0.27% to 0.06% after centrifugation. The filter residue II mainly consists of fine fibers and larger particles of packing material lost with the white water from the online slurry. The purification treatment in steps 1) and 2) can significantly reduce the suspended solids content in the white water, reduce the treatment load of subsequent membrane purification, and reduce the cleaning frequency of the membrane purification system.

[0034] 3) The centrifuged white water obtained in step 2) is subjected to deep purification through a ceramic ultrafiltration membrane to obtain clear white water and sludge. The clear white water does not contain suspended solids. The ceramic ultrafiltration membrane used has a pore size of 40 nm and an operating pressure of 0.1 MPa-0.2 MPa.

[0035] 4) The purified clear water is adsorbed using a resin-filled chromatography column. Countercurrent adsorption is performed using a gradient flow rate from high to low. The sample is stopped after the adsorption is complete. The preferred resin type is the weakly polar macroporous adsorption resin LS200.

[0036] Specifically, before adsorption, the main alkaloids in the purified clear water were nicotine, nornicotine, neonicotine, and pseudoequisetine, with concentrations of 72 mg / L, 2.54 mg / L, 7.01 mg / L, and 0.78 mg / L, respectively. Nicotine accounted for 85% of the alkaloids by mass.

[0037] The specific process parameters for gradient adsorption are as follows: The first gradient adsorption flow rate is 20 BV / h, and the treated white water volume is 57.1 BV. At this point, the nicotine concentration in the effluent reaches 1.64% of the initial nicotine mass concentration in the clarified white water. The second gradient adsorption flow rate is adjusted to 14 BV / h, and the treated white water volume is 28.6 BV. At this point, the nicotine concentration in the effluent is approximately 1% of the initial nicotine mass concentration in the clarified white water. The third gradient adsorption flow rate is adjusted to 8 BV / h, and the treated white water volume is 78.6 BV. At this point, the nicotine concentration in the effluent is approximately 11% of the initial nicotine mass concentration in the clarified white water. Adsorption is then stopped, and the total treated white water volume is approximately 164 BV.

[0038] In step 4), during the gradient adsorption on the resin chromatography column, the adsorption curves of nicotine, nornicotine, neonicotinoids, and pseudoestilide are shown below. Figure 2 When the leakage standard is defined as the concentration of alkaloids in the effluent reaching 10% of the corresponding alkaloid mass concentration in the clear water, the order of leakage is nicotine, pseudoequisetine, neonicotine and nicotine, and the volume of clear water treated when they leak is 36 BV, 43 BV, 71 BV and 164 BV respectively.

[0039] To increase the proportion of nicotine in the alkaloids in the recovered material, this invention selects a treatment volume of 164 BV for the clarified white water, that is, the treatment volume of clarified white water is based on the amount of nicotine that reaches the leakage point.

[0040] This is because if the second or third gradient flow rate is consistently selected for adsorption from start to finish, the nicotine concentration in the effluent will reach the leakage endpoint more quickly, resulting in a lower volume of treated white water. For example, at an adsorption flow rate of 20 BV / h, only 92 BV of white water is treated, and at an adsorption flow rate of 14 BV / h, only 114 BV of white water is treated. If the first gradient flow rate is consistently selected for adsorption from start to finish, the volume of white water treated at the leakage point is relatively higher than that treated at higher adsorption flow rates, but the treatment time is longer. For example, at an adsorption flow rate of 8 BV / h, the treatment time is 20.5 hours. Furthermore, both of these gradient adsorption methods have the disadvantages of long treatment time and low volume of treated white water.

[0041] Therefore, this invention optimizes the adsorption flow rate and the amount of white water to be treated during gradient adsorption. Ultimately, the amount of water treated by this invention is close to that treated with an adsorption flow rate of 8 BV / h, while the treatment time is only 14.7h, which can shorten the adsorption time by 5.8h, thus greatly reducing the adsorption time.

[0042] 5) After adsorption is complete, use 2 BV of distilled water at a flow rate of 10 BV / h to wash away the residual white water in the chromatography column and wash away the nicotine and neonicotinoids that are weakly bound to the resin.

[0043] 6) After cleaning, elution is performed using an elution solvent (anhydrous acetone is used in this embodiment) to quickly displace the residual water in the chromatography column at a high flow rate, while avoiding the elution of pigments adsorbed by the resin, thus reducing the pigment content in the subsequent eluent; the flow rate of the elution solvent is 0.9 BV / h, and the amount of elution solvent used is 2.5 BV.

[0044] Elution should be stopped when more than 95% of the components in the effluent are the elution solvent, and the mixture should be allowed to stand for 40 minutes. Anhydrous ethanol or methanol should not be used as the elution solvent because when anhydrous ethanol or methanol is used for elution, the solvent concentration decreases when the organic solvent comes into contact with water. At this time, the pigment will be eluted before the fragrance substances such as nicotine. The pigment will be coated on the surface of this type of filler, making it difficult for the fragrance components to be eluted later. This will increase the amount of elution solvent used and the time required. This phenomenon will not occur when acetone is used for elution.

[0045] 7) After elution, 5% (volume fraction) of distilled water is added to the eluent, and then acetone in the eluent is removed by distillation and the acetone is recovered. The residue is the target solution. The nicotine concentration in the target solution is 92 g / L, the mass percentage of nicotine in the alkaloids is 94.3%, and the mass percentages of nornicotine and neonicotine in the alkaloids are 1.0% and 4.2% respectively. The recovery rate of nicotine is 98%, while the recovery rates of nornicotine and neonicotine are not higher than 50%.

[0046] The resin of this invention can specifically enrich nicotine. Under high flow rate conditions, neonicotinoids and nornicotinoids are first allowed to leak out. Then, when only a small amount of nicotine has leaked out, the flow rate is reduced in three stages. At this point, neonicotinoids, nornicotinoids, and pseudoequisetine are always in a leaking state, which means that the resin no longer enriches them. However, nicotine can still be enriched. This achieves adsorption from high flow rate to low flow rate, thereby greatly shortening the adsorption time. Furthermore, in this way, the resin mainly enriches nicotine, while other components (nornicotinoids, neonicotinoids, etc.) are enriched with very little, thereby achieving the separation of nicotine, nornicotinoids, and neonicotinoids and increasing the proportion of nicotine in the clear water.

[0047] In addition, compared with the prior art (CN113498875A A method and application for recovering aroma substances in reconstituted tobacco leaf white water), it can be seen that the method of this application directly adds ethanol during elution and then lets the ethanol flow out slowly. This results in the ethanol being at a relatively low initial concentration when it combines with the water in the column, which easily leads to the elution of pigments.

[0048] The method of this invention rapidly displaces the solution in the column during elution. This is equivalent to the elution solvent (acetone) replacing the solution in the column with acetone before it can be diluted. This ensures that the pigment remains on the packing material, and the main component eluted is nicotine. As a result, the pigment content in the final recovery solution is very low, avoiding the negative impact on subsequent processes caused by a large amount of pigment in the recovery solution.

[0049] The present invention describes a method for recovering high-nicotine aroma substances from recycled tobacco white water. First, the white water from the papermaking process is purified through multiple stages using an arc screen, a horizontal screw centrifuge, and a ceramic ultrafiltration membrane to obtain clear white water. Then, a macroporous resin packing material that selectively enriches nicotine in wastewater is used for column adsorption in a gradient flow rate manner to achieve the recovery of alkaloids. After adsorption, an elution solvent is used to elute and concentrate the product using a specific process to obtain a high-nicotine aroma substance.

[0050] This technical solution is highly efficient, processes a large volume of white water, and effectively increases the proportion of nicotine in the alkaloids in the recovered materials. Furthermore, the resin can be reused, resulting in low cost, and the treated water can be recycled in production, reducing water consumption.

[0051] Finally, it should be noted that the above are merely preferred embodiments and application principles of the present invention. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the specific embodiments described herein, and may include many other effective embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for recovering high-nicotine aroma substances from reconstituted tobacco white water, characterized in that, Includes the following steps: 1) Collect, filter, centrifuge, and purify the white water generated during the papermaking process in the production of reconstituted tobacco to obtain clear white water; 2) The purified clear water is adsorbed using a resin-filled chromatography column, and countercurrent adsorption is performed using a gradient flow rate from high to low. 3) After adsorption is complete, rinse the residual solution in the chromatography column with no less than 2 column volumes of distilled water or tap water at a certain flow rate; 4) After cleaning, use an elution solvent to elute. Stop elution when more than 95% of the components in the effluent are the elution solvent by volume, and let it stand for 20 to 60 minutes. 5) After elution, add distilled water to the eluent at a volume not exceeding 10% of its volume, and then remove the organic solvent from the eluent by one or more combinations of nitrogen blowing, rotary evaporation or distillation to obtain the target solution; The specific steps for collection, filtration, centrifugation, and purification in step 1) are as follows: The white water generated during the papermaking process in the production of reconstituted tobacco is collected, filtered, and filtered white water and filter residue I are obtained. The obtained filtered white water was centrifuged to obtain centrifuged white water and filter residue II; The obtained centrifuged white water is then purified through an ultrafiltration membrane to obtain clear white water and sludge. In step 2), the resin type is weakly polar macroporous adsorption resin LS200; In step 2), the specific gradient adsorption process parameters are as follows: the adsorption flow rate is initially set at 17~25 BV / h to start the sample flow. When the nicotine concentration in the effluent reaches 1.5%~2% of the initial nicotine mass concentration in the clear white water, the flow rate is switched to 12~16 BV / h. When the nicotine concentration in the effluent reaches 1%~1.5% of the initial nicotine mass concentration in the clear white water, the flow rate is switched to 5~10 BV / h. Adsorption is stopped when the nicotine concentration in the effluent reaches 10%~20% of the initial nicotine mass concentration in the clear white water. In step 4), the flow rate of the elution solvent should not exceed 2 BV / h, and the amount of elution solvent used should be 1.5 to 3 times the column volume. In step 4), the elution solvent is anhydrous acetone.

2. The method for recovering high-nicotine aroma substances from reconstituted tobacco white water according to claim 1, characterized in that, In step 1), ultrafiltration membranes are used to purify the white water after centrifugation. The ultrafiltration membrane used is a ceramic ultrafiltration membrane with a pore size of no more than 50 nm and an operating pressure of 0.1 MPa to 0.2 MPa.

3. The method for recovering high-nicotine aroma substances from reconstituted tobacco white water according to claim 1, characterized in that, The collected white water was filtered through an arc screen to obtain filtered white water and filter residue I. The mass percentage of suspended solids in the white water decreased from 0.40% to 0.27% after filtration.

4. The method for recovering high-nicotine aroma substances from reconstituted tobacco white water according to claim 1, characterized in that, The filtered white water was centrifuged using a horizontal screw centrifuge to obtain centrifuged white water and filter residue II. The mass percentage of suspended solids in the white water decreased from 0.27% to 0.06% after centrifugation.

5. The method for recovering high-nicotine aroma substances from reconstituted tobacco white water according to claim 1, characterized in that, Before adsorption, the main alkaloids in the purified clear water were nicotine, nornicotine, neonicotine, and pseudoestidinine, with concentrations of 72 mg / L, 2.54 mg / L, 7.01 mg / L, and 0.78 mg / L, respectively. Nicotine accounted for 85% of the alkaloids by mass.

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