Tobacco stem-based perfuming granular material as well as preparation method and application thereof

Abstract

The invention discloses a tobacco stem-based perfuming granular material as well as a preparation method and application thereof. According to the method, tobacco stems with rich pore structures are subjected to hydrothermal carbonization, miscellaneous gas is removed, holes are formed in the surface of the hydrothermal carbon in an etching mode, low-volatility liquid paraffin is adsorbed to the pore surfaces of the hydrothermal carbon, the liquid paraffin serves as a binding agent to enhance the interaction force between the hydrothermal carbon and essence by means of the thermal stability and high viscosity of the liquid paraffin, and the flavor of the tobacco stems is improved. The storage stability of the essence is enhanced; and finally, the low-temperature release performance is improved by adding the high-thermal-conductivity nanosheets. The tobacco stem-based perfuming granular material with high adsorption capacity, high stability and excellent low-temperature release performance is prepared, and the technical problems of low utilization efficiency of tobacco stem resources, poor performance of filter stick perfuming granular materials and the like are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of cigarette filter materials, and particularly relates to a tobacco stem-based flavor-loaded particulate material, a preparation method thereof and an application thereof. Background Art

[0002] At present, the technological innovation of cigarette products mainly focuses on the innovation of filter rod improvement technology, which plays a crucial role in the development of cigarette products and the operation of brand markets. Among them, adding a flavor-functional carrier material to the cigarette filter rod is an important strategy to improve the taste and quality of cigarettes. There are various flavoring methods for cigarette filter rods, such as the adsorbent method, the solvent method, the flavor wire method, the capsule method, and the composite flavoring method, etc. The adsorbent method uses a porous solid adsorbent to adsorb the essence, and then the adsorbent is added to the filter material to make a composite filter rod. The adsorbent method can delay the volatilization loss of the essence and ensure the uniform release of the aroma during the smoking process. In addition, flavoring the cigarette filter rod can not only prevent the added essence from participating in the combustion reaction of the tobacco shreds and causing waste, but also achieve efficient release control of the essence substances through the heat in the smoking combustion flue gas. At the same time, it can avoid the loss of the essence during the static combustion of the cigarette, reduce the retention of the essence by the tobacco shreds and the filter tip, etc., increase the transfer efficiency, facilitate the increase of the content of low-boiling-point essence substances in the mainstream flue gas, and ultimately improve the aroma sensory quality of cigarette smoking. Currently, binary and ternary composite flavoring filter rods are widely used in the tobacco industry. Their preparation process is complex and the cost is high. Porous materials, due to their large specific surface area and certain porosity, can not only adsorb harmful components (such as heavy metals, tar, etc.) in the flue gas and reduce the harm to the smoker's body, but also endow the cigarette with a unique flavor by loading and releasing the essence, etc. Among them, porous materials, due to their certain specific surface area, porosity and excellent stability, etc., are widely used as essence loading materials in the flavor enhancement of cigarette filter rods.

[0003] The filter rod flavoring technology has the following three advantages. First, it can reduce the loss and pyrolysis of the essence during the storage and smoking of cigarettes. The temperature of the filter rod is relatively low (about 40 - 60 °C), which will not change the composition of the flavor substances, and thus meet the requirement of pure flavor. Second, adding the essence to the filter rod can improve the utilization rate of the essence. Third, various flavoring methods can be used to meet the controllability requirements of different essence storage and release.

[0004] Requirements for porous materials loaded with essence in cigarette filter rods: They should have a certain specific surface area and surface pore structure, so as to have a large loading capacity for the essence; the release temperature of the essence in the filter rod is relatively low (about 40 - 60 °C), and it is required to release quickly at this temperature; the loaded essence should have good stability at room temperature. To meet the above requirements, the commonly used porous materials at present mainly include: activated carbon, molecular sieve, hollow nanosilica spheres, nano-active ceramics, etc.

[0005] Activated carbon is generally prepared by high-temperature carbonization and activation. Due to its characteristics such as high specific surface area, adjustable pore size, good electrical and thermal conductivity, etc., as a fragrance carrier material for loading fragrances, it has the characteristics of large adsorption capacity and excellent storage stability, and has a large application in the cigarette industry. Wang Ying (Light Industry Science and Technology, 2015, No. 11) studied and found that activated carbon particles have good slow-release performance and long-lasting fragrance retention effect for adsorbing jasmine fragrance. After 30 days, the fragrance content is still 70% of the initial amount. However, due to its relatively high specific surface area, it is difficult to meet the rapid low-temperature release performance of the fragrance at the filter rod. CN 112551524 A discloses a tobacco stem-based hierarchical porous carbon material, its preparation method and application. Using tobacco stems as the carbon source, carbonates and oxalates as grinding aids and activators, the tobacco stem-based hierarchical porous carbon material is prepared by "one-pot ball milling activation". It has a large specific surface area, a high ratio of mesoporous channels, and a large adsorption capacity for fragrances. However, due to its overly abundant pores and high specific surface area, it is not conducive to the low-temperature slow release of the fragrance in the filter rod. CN116268563A discloses a functional plant particle for enhancing the fragrance of the filter rod, its preparation method and application, which is prepared from natural plant powder, phase change polymer material, and tobacco fragrance. Among them, the mass ratio of natural plant powder is 30-70%, the mass ratio of phase change polymer material is 20-60%, and the mass ratio of tobacco fragrance is 5-20%. First, the tobacco fragrance is mixed evenly with the phase change polymer material in a molten state, and then mixed and kneaded evenly with the natural plant powder. The particles for enhancing the fragrance of the filter rod are prepared by the extrusion granulation method. The adsorption capacity of the fragrance is high, the fragrance substances are not easy to volatilize, and the storage stability is good. However, there are problems that the coating of the fragrance is too dense and the thermal conductivity of the natural plant is poor, and the fragrance release ability is weak, especially it is difficult to be used for the release of the fragrance at the low temperature of the filter rod. In view of the above problems, researchers have proposed a strategy of adding phase change materials and thermal conductive materials to the filter rod material. For example, CN 108451054 A provides a tobacco core material for heat-not-burn cigarettes. Due to the addition of a thermal conductive material, it can conduct heat evenly. During the heating process, the tobacco core paper is heated evenly. In addition, the present invention uses a phase change material, and the phase change material absorbs heat under heating conditions, avoiding local overheating of the tobacco core material paper during the heating process. CN109722912A sprays a high thermal conductive filler on the non-woven fabric to prepare a microcapsule fragrance composite material for self-heating products, which relates to the technical field of self-heating products and solves the problem that the fragrance of the self-heating products is greatly weakened after being placed for a period of time due to the adsorption of the activated carbon in the self-heating products on the fragrance. However, in the above technologies, the phase change material or the thermal conductive material and the tobacco core material are only physically compounded, and are not adsorbed in the material pores, and cannot be used for the release of the low-temperature fragrance at the filter rod.

[0006] Plants such as tobacco stems, tea stems, and bagasse have porous structures, original aromas, and functional chemical components in themselves, and have great advantages as flavoring materials. For example, natural plants contain antioxidant components that can undergo chemical reactions with harmful components in mainstream smoke, playing a role in reducing tar and harm. In addition, plants also contain many organic compound components, most of which are flavor substances, antioxidant substances, etc. If applied to filter rods, it can not only achieve the effects of enhancing flavor, reducing tar and harm, but also comprehensively improve the taste and quality of cigarettes. Especially when plants are used as flavor carrier materials in cigarette filters, they have the advantages of not participating in combustion and not generating other toxic and harmful substances, and can also effectively reduce harmful components in smoke. They can not only remove miscellaneous odors, retain some of their own aromas, but also endow cigarettes with appropriate aromas.

[0007] However, untreated plants have a relatively small specific surface area, and most of their pore structures are macropores with smooth pore walls, which is not conducive to the adsorption, loading, and storage stability of flavors. To increase their specific surface area and regulate the pore structure, common methods mainly include hydrothermal treatment, chemical treatment, and microwave treatment, etc. Hydrothermal carbonization is a green, sustainable, and low-cost method for preparing porous carbon materials, which can convert biomass raw materials into homogeneous, energy-intensive, and highly chemically and thermally stable hydrochar. The added water not only acts as a solvent, but also participates in the hydrothermal reaction as a catalyst, reactant, and medium for transferring energy. The temperature of hydrothermal carbonization generally ranges from 160 to 350 °C, and the reaction system is in a subcritical state. The dielectric constant of water decreases significantly and is easily decomposed into hydronium ions (H3O + ) and hydroxide ions (OH - ), which play acid-base catalytic roles under specific conditions. In addition, the properties of subcritical water such as polarity, molecular diffusivity, and viscosity change, improving its solubility for medium-polar or non-polar compounds. At the same time, there is a temperature gradient in the system, which can promote the convection between solutions and the transport of solutes. Therefore, hydrothermal carbonization generally has a relatively fast chemical reaction rate and can efficiently convert biomass into hydrochar, which has broad application prospects in filter rod flavor carriers.

[0008] Tobacco stems are the main by-products in the cigarette industry. At present, most of the tobacco stem waste in China is treated by incineration or stacking, resulting in serious waste of resources and environmental protection problems. Tobacco stems are rich in carbohydrates such as lignin, cellulose and hemicellulose. During the hydrothermal carbonization process, a series of reactions such as hydrolysis, dehydration, decarboxylation, polycondensation and aromatization occur, while dissolving the harmful components in the plant and significantly reducing the ash content. Due to the mild hydrothermal treatment process, high hydrochar yield, and easy regulation of the pore structure of hydrochar, tobacco-stem-based hydrochar has attracted attention as an adsorbent. For example, Chinese invention patent CN113731374 A discloses that the hydrochar of tobacco stems cross-linked and modified under alkaline conditions has good adsorption effect on heavy metals. Therefore, there is great potential in applying tobacco-stem hydrochar to the field of perfume adsorption. Using tobacco stems as raw materials, through hydrothermal treatment technology to remove part of the lignin and cellulose, and etching the surface of plant waste to prepare plant hydrochar, which can remove its own miscellaneous odor while retaining part of its own fragrance, and can also be additionally loaded with a certain amount of perfume matching its fragrance to comprehensively improve the taste of cigarettes, which will provide technical support for the development of composite filter rods with characteristic flavors and the creation of special products, and at the same time can realize the high-value utilization of natural plant tobacco stems.

[0009] In summary, the hydrochar prepared by the existing technologies or processes at present has low specific surface area, low thermal conductivity and weak interaction with perfume, resulting in low perfume loading. As a perfume loading material, it has low room temperature stability and poor low temperature release performance, and is difficult to be applied in cigarette filter rods. Summary of the Invention

[0010] To solve the disadvantages and deficiencies of the existing technologies, the primary object of the present invention is to provide a preparation method of a tobacco-stem-based flavor-loaded particle material. Hydrothermal carbonization of tobacco-stem hydrochar with wide sources, low price and rich pore structure is carried out, and the tobacco-stem-based hydrochar is organically compounded with liquid paraffin and high thermal conductivity nanosheets to prepare a tobacco-stem-based flavor-loaded particle material with high adsorption capacity, strong stability and excellent low temperature release performance, solving technical problems such as low utilization efficiency of tobacco stem resources and poor performance of filter rod flavor-loaded particle materials.

[0011] Preparation mechanism: After the tobacco stem raw material is subjected to alkaline hydrothermal carbonization, the miscellaneous odor is removed and pores are etched on the surface of the hydrochar. Then, the low volatility liquid paraffin is adsorbed on the surface of its pores. Using the thermal stability and high viscosity of liquid paraffin as a binder to enhance the interaction between the hydrochar and the perfume, thereby enhancing the storage stability of the perfume; finally, by adding high thermal conductivity nanosheets, the low temperature release performance is improved.

[0012] Another object of the present invention is to provide a tobacco-stem-based flavor-loaded particle material prepared by the above preparation method, which has excellent perfume storage stability and rapid release performance in filter rods.

[0013] Another object of the present invention is to provide the above-mentioned tobacco stem-based flavor-loaded particulate material with excellent flavor adsorption stability and release performance for use in enhancing the flavor of cigarette filters, with the flavor adsorption efficiency exceeding 80%, the flavor loss rate not exceeding 50% after seven days, and the flavor release rate exceeding 50% at 40-60°C for 600 s.

[0014] The object of the present invention is achieved by the following technical solutions:

[0015] A preparation method of a tobacco stem-based flavor-loaded particulate material with excellent flavor adsorption stability and release performance, comprising the following steps:

[0016] (1) Hydrothermally react tobacco stems in a potassium-based alkaline salt aqueous solution to obtain tobacco stem-based hydrochar;

[0017] (2) Adsorb liquid paraffin on the tobacco stem-based hydrochar at 60-80°C, then mix it evenly with a flavor ethanol solution and highly thermally conductive nanosheets at 40°C or below, and finally dry it in a fluidized bed dryer to obtain a tobacco stem-based hydrochar flavor-loaded material.

[0018] Preferably, the mesh number of the tobacco stems in step (1) is 30-80 mesh; more preferably 30-50 mesh.

[0019] Preferably, in the potassium-based alkaline salt aqueous solution in step (1), the potassium-based alkaline salt is at least one of KOH, K2CO3, and KHCO3.

[0020] Preferably, the pH of the potassium-based alkaline salt aqueous solution in step (1) is 10-13.

[0021] Preferably, the temperature of the hydrothermal reaction in step (1) is 150-210°C, and the heat preservation time is 30-90 min; more preferably, the temperature of the hydrothermal reaction is 180-200°C, and the heat preservation time is 60-90 min.

[0022] Preferably, the time for the tobacco stem-based hydrochar to adsorb liquid paraffin at 60-80°C in step (2) is 60-120 minutes.

[0023] Preferably, the mass ratio of the tobacco stem-based hydrochar, liquid paraffin, flavor ethanol solution, and highly thermally conductive nanosheets in step (2) is 100:(5-20):100:(2-20), more preferably 100:(10-15):100:(5-10).

[0024] Preferably, the boiling point of the liquid paraffin in step (2) is higher than 300°C, and the viscosity at 20-60°C is 10-30 mPa·s.

[0025] Preferably, the mass concentration of the flavor in the flavor ethanol solution in step (2) is 2-10 wt%.

[0026] Preferably, the highly thermally conductive nanosheet in step (2) is one of boron nitride, aluminum nitride, and silicon carbide.

[0027] Preferably, the size of the highly thermally conductive nanosheet in step (2) is such that the sheet diameter is greater than 0.5 - 2 μm and the thickness is 2 - 10 nm.

[0028] Preferably, the temperature for mixing the tobacco stem - based hydrochar, the essence ethanol solution, and the highly thermally conductive nanosheet in step (2) is 25 - 40°C.

[0029] Preferably, the mixing time of the tobacco stem - based hydrochar, the essence ethanol solution, and the highly thermally conductive nanosheet in step (2) is 30 - 120 minutes.

[0030] Preferably, the essence in step (2) is a plant - based liquid essence soluble in absolute ethanol; more preferably, it is at least one of sweet orange essence and blueberry essence.

[0031] Preferably, the air flow rate of the fluidized bed dryer in step (2) is 0.5 - 2 m / s; the drying temperature is 30 - 60°C; and the drying time is 10 - 30 minutes.

[0032] The preparation method of the above - mentioned tobacco stem - based flavor - loaded granular material with excellent essence adsorption stability and release performance includes the following steps:

[0033] (1) Add tobacco stems to water, then add a potassium - based alkaline regulator to adjust the pH value to 10 - 13, carry out hydrothermal reaction, cool to room temperature, filter, wash with water, and dry to obtain tobacco stem - based hydrochar;

[0034] (2) Adsorb the tobacco stem - based hydrochar and liquid paraffin at 60 - 80°C for 60 - 120 minutes, then mix evenly with the essence ethanol solution and the highly thermally conductive nanosheet at 40°C or below, and finally dry with a fluidized bed dryer to obtain a tobacco stem - based hydrochar essence - loaded material.

[0035] Preferably, the mass ratio of the tobacco stems to water in step (1) is 1:(5 - 20).

[0036] Preferably, the potassium - based alkaline regulator in step (1) is an aqueous solution with a mass concentration of 10 - 20%, and the solute is a potassium - based alkaline salt, specifically at least one of KOH, K2CO3, and KHCO3.

[0037] Preferably, the drying in step (1) includes at least one of drying methods such as forced - air drying, vacuum drying, and infrared drying.

[0038] Preferably, the drying temperature in step (1) is 100 - 120°C, and the drying time is 6 - 12 hours.

[0039] The present invention also provides a tobacco stem-based flavor-loaded particulate material prepared by the above preparation method.

[0040] The present invention also provides the application of the above-mentioned tobacco stem-based flavor-loaded particulate material.

[0041] Preferably, it is applied in cigarette filter materials.

[0042] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0043] (1) Compared with traditional commercial activated carbon flavor-loaded materials, the flavor storage stability and flavor slow-release performance of the tobacco stem-based flavor-loaded particulate material prepared by the present invention can be significantly improved. As a flavor-loaded material agent, it can efficiently and rapidly load and uniformly release liquid flavor, and has broad application prospects in cigarette filter rods.

[0044] (2) The present invention uses potassium carbonate as an alkaline regulator and a hydrothermal process activator. Hemicellulose is easily hydrolyzed under alkaline conditions and forms a relatively developed pore structure on the surface of hydrothermal carbon. Moreover, the material after hydrothermal treatment is mainly amorphous carbon, and there are a large number of oxygen-containing functional groups on its surface, which can provide more active sites for flavor loading.

[0045] (3) The present invention uses high-stability liquid paraffin with a relatively high viscosity to prevent excessive adsorption of flavor inside the pores of hydrothermal carbon, so as to facilitate its rapid release at 40-60 °C. Description of the Drawings

[0046] Figure 1 is a scanning electron micrograph of the tobacco stem-based flavor-loaded particulate material obtained in Example 1 of the present invention.

[0047] Figure 2 is the nitrogen adsorption / desorption isotherm and pore size distribution curve of the tobacco stem-based flavor-loaded particulate material obtained in Example 1 of the present invention. Detailed Embodiments

[0048] The present invention will be further described in detail below with reference to the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0049] In the embodiments of the present invention, those not specified under specific conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. The raw materials, reagents, etc. that are not specified for the manufacturer can be obtained as conventional products through commercial purchase.

[0050] Example 1

[0051] In a hydrothermal kettle, 100 g of 30 mesh tobacco stems are added to 500 g of water, 10 wt% potassium carbonate solution is added to adjust the pH to 10, the temperature is raised to 150°C, the temperature is kept at this temperature for 30 minutes, the reaction is cooled to room temperature, and the filter residue is placed in a vacuum dryer at 100°C for 6 hours to obtain tobacco stem-based hydrothermal carbon; 100 g of tobacco stem-based hydrothermal carbon is weighed, 5 g of liquid rock having a viscosity of 10 mPa·s at 20-60°C and a boiling point of 310°C is added, and the mixture is stirred for 10 minutes. The mixture was added with 100 g of 2 wt% blueberry flavor ethanol solution (the mass ratio of anhydrous ethanol to flavor was 98:2) and mixed with 2 g of boron nitride (with a flake diameter of 0.5 μm and a thickness of 2 nm). The mixture was stirred for 30 min to allow the hydrothermal charcoal to fully absorb the flavor. The mixture was put into a fluidized bed dryer and dried for 10 minutes at a temperature of 30 ° C and an air flow velocity of 0.5 m / s to obtain a tobacco stem-based flavoring granular material.

[0052] Example 2

[0053] In a hydrothermal kettle, 100 g of tobacco stems with a mesh size of 80 meshes are added to 2000 g of water, 20 wt% potassium carbonate solution is added to adjust the pH to 10, the temperature is raised to 210°C, and the temperature is kept at this temperature for 90 minutes. After the reaction, it is cooled to room temperature and filtered. The filter residue is placed in a vacuum dryer at 120°C for 12 hours to obtain tobacco stem-based hydrothermal carbon; 100 g of tobacco stem-based hydrothermal carbon is weighed, 20 g of liquid rock with a viscosity of 30 mPa·s at 20-60°C and a boiling point of 310°C is added, and the mixture is stirred for 10 minutes. The mixture was stirred for 30 minutes to allow the hydrothermal charcoal to fully absorb the essence. The mixture was placed in a fluidized bed dryer and dried for 10 minutes at a temperature of 60°C and an air flow rate of 2m / s to obtain a tobacco stem-based flavoring granular material.

[0054] Example 3

[0055] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C, and the holding time at this temperature was 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter residue was placed in a vacuum dryer at 100 °C for 8 h to obtain hydrothermal carbon based on tobacco stems. 100 g of the hydrothermal carbon based on tobacco stems was weighed, and 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added. It was adsorbed in a constant temperature shaker at 60 °C for 60 min, then cooled to 40 °C. Then, 100 g of a 2 wt% orange essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2) and 10 g of aluminum nitride (with a particle diameter of 2 μm and a thickness of 10 nm) were fully mixed, and stirred for 30 min to allow the hydrothermal carbon to fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the flavor - endowed granular material based on tobacco stems.

[0056] Example 4

[0057] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1500 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C, and the holding time at this temperature was 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter residue was placed in a vacuum dryer at 100 °C for 8 h to obtain hydrothermal carbon based on tobacco stems. 100 g of the hydrothermal carbon based on tobacco stems was weighed, and 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added. It was adsorbed in a constant temperature shaker at 60 °C for 60 min, then cooled to 40 °C. Then, 100 g of a 2 wt% black tea essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2) and 10 g of boron nitride (with a particle diameter of 2 μm and a thickness of 5 nm) were fully mixed, and stirred for 30 min to allow the hydrothermal carbon to fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the flavor - endowed granular material based on tobacco stems.

[0058] Example 5

[0059] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 11. The temperature was raised to 180 °C, and the mixture was kept at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco stem-based hydrochar. 100 g of the tobacco stem-based hydrochar was weighed, and 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added. It was adsorbed in a constant-temperature shaker at 60 °C for 60 min, then cooled to 40 °C. Subsequently, 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2) and 5 g of boron nitride (flake diameter of 1 μm and thickness of 5 nm) were added and thoroughly mixed. Stirring was carried out for 30 min to allow the hydrochar to fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco stem-based flavor-loaded granular material.

[0060] Example 6

[0061] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C, and the mixture was kept at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco stem-based hydrochar. 100 g of the tobacco stem-based hydrochar was weighed, and 15 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added. It was adsorbed in a constant-temperature shaker at 60 °C for 60 min, then cooled to 40 °C. Subsequently, 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2) and 10 g of boron nitride (flake diameter of 1 μm and thickness of 10 nm) were added and thoroughly mixed. Stirring was carried out for 30 min to allow the hydrochar to fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco stem-based flavor-loaded granular material.

[0062] Example 7

[0063] In a hydrothermal kettle, 100 g of 50-mesh tobacco stems were added to 1000 mL of water, 20 wt% potassium carbonate solution was added to adjust the pH to 10, the temperature was raised to 180°C, the temperature was kept at this temperature for 60 min, the reaction was cooled to room temperature, and the filter residue was placed in a vacuum dryer at 100°C for 8 h to obtain tobacco stem-based hydrothermal carbon; 100 g of tobacco stem-based hydrothermal carbon was weighed, 10 g of liquid having a viscosity of 20 mPa·s at 20-60°C and a boiling point of 310°C was added, and the mixture was stirred for 1 h. The mixture was added with paraffin wax and adsorbed in a constant temperature shaker at 60°C for 60 minutes, then cooled to 40°C, and then 100g of 2wt% blueberry flavor ethanol solution (the mass ratio of anhydrous ethanol to flavor is 98:2) and 10g of boron nitride (with a flake diameter of 1 μm and a thickness of 10nm) were added and fully mixed. The mixture was stirred for 30 minutes to allow the hydrothermal charcoal to fully adsorb the flavor. The mixture was put into a fluidized bed dryer and dried for 10 minutes at a temperature of 40°C and an airflow velocity of 1m / s to obtain a tobacco stem-based flavoring granular material.

[0064] Example 8

[0065] In a hydrothermal kettle, 100 g of 50 mesh tobacco stems were added to 1000 mL of water, 20 wt% potassium carbonate solution was added to adjust the pH to 10, the temperature was raised to 180°C, the temperature was kept at this temperature for 90 min, the reaction was cooled to room temperature, and the filter residue was placed in a vacuum dryer at 100°C for 8 h to obtain tobacco stem-based hydrothermal carbon; 100 g of tobacco stem-based hydrothermal carbon was weighed, 10 g of liquid with a viscosity of 20 mPa·s and a boiling point of 310°C at 20-60°C was added, and the mixture was stirred for 1 h. The mixture was added with paraffin wax and adsorbed in a constant temperature shaker at 60°C for 60 minutes, then cooled to 40°C, and then 100g of 2wt% blueberry flavor ethanol solution (the mass ratio of anhydrous ethanol to flavor is 98:2) and 10g of boron nitride (with a flake diameter of 2μm and a thickness of 10nm) were added and fully mixed. The mixture was stirred for 30 minutes to allow the hydrothermal charcoal to fully adsorb the flavor. The mixture was put into a fluidized bed dryer and dried for 10 minutes at a temperature of 40°C and an airflow velocity of 1m / s to obtain a tobacco stem-based flavoring granular material.

[0066] Example 9

[0067] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C and maintained at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain hydrothermal carbon based on tobacco stems. 100 g of the hydrothermal carbon based on tobacco stems was weighed, 10 g of liquid paraffin with a viscosity of 20 mPa·s and a boiling point of 310 °C was added, and it was adsorbed in a constant temperature shaker at 60 °C for 60 min. Then it was cooled to 40 °C, and then 100 g of 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2) and 15 g of boron nitride (flake diameter is 2 μm and thickness is 10 nm) were fully mixed, and stirred for 30 min to make the hydrothermal carbon fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the flavor-added granular material based on tobacco stems.

[0068] Comparative Example 1 (using solid paraffin with a phase change temperature of 50 °C)

[0069] In a hydrothermal autoclave, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C and maintained at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain hydrothermal carbon based on tobacco stems. 100 g of the hydrothermal carbon based on tobacco stems was weighed, 10 g of solid paraffin with a phase change temperature of 50 °C was added and adsorbed in a constant temperature shaker at 60 °C for 60 min. Then it was cooled to 40 °C, and then 100 g of 2 wt% blueberry essence ethanol solution and 10 g of boron nitride (flake diameter is, thickness is) were fully mixed, and stirred for 30 min to make the hydrothermal carbon fully adsorb the essence. It was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the flavor-added granular material based on tobacco stems.

[0070] Comparative Example 2 (different addition orders of paraffin and essence)

[0071] In a hydrothermal reactor, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water, and a 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C, and the mixture was kept at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco stem-based hydrochar. 100 g of the tobacco stem-based hydrochar was weighed, and 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence was 98:2) and 10 g of boron nitride (with a certain particle size and thickness) were added and mixed well. Stir for 30 min to allow the hydrochar to fully adsorb the essence. Then, 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added, and the mixture was adsorbed in a constant temperature shaker at 60 °C for 60 min. Then, it was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco stem-based flavor-loaded granular material.

[0072] Comparative Example 3 (using sodium hydroxide instead of potassium carbonate)

[0073] In a hydrothermal reactor, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water, and a 20 wt% sodium hydroxide solution was added to adjust the pH to 10. The temperature was raised to 180 °C, and the mixture was kept at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco stem-based hydrochar. 100 g of the tobacco stem-based hydrochar was weighed, and 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added, and the mixture was adsorbed in a constant temperature shaker at 60 °C for 60 min. Then, it was cooled to 40 °C, and 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence was 98:2) and 10 g of boron nitride (with a certain particle size and thickness) were added and mixed well. Stir for 30 min to allow the hydrochar to fully adsorb the essence. Then, it was placed in a fluidized bed dryer and dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco stem-based flavor-loaded granular material.

[0074] Comparative Example 4 (using a fixed bed dryer)

[0075] In a hydrothermal reactor, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C and maintained at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco-stem-based hydrochar. 100 g of the tobacco-stem-based hydrochar was weighed, 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C and a boiling point of 310 °C was added, and it was adsorbed in a constant-temperature shaker at 60 °C for 60 min. Then it was cooled to 40 °C, and 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence was 98:2) and 10 g of boron nitride (flake diameter and thickness) were added and thoroughly mixed. It was stirred for 30 min to allow the hydrochar to fully adsorb the essence, and then placed in a fixed-bed dryer. It was dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco-stem-based flavor-loaded granular material.

[0076] Comparative Example 5 (physical mixing of liquid paraffin and hydrochar without an adsorption process)

[0077] In a hydrothermal reactor, 100 g of tobacco stems with a mesh size of 50 were added to 1000 mL of water. A 20 wt% potassium carbonate solution was added to adjust the pH to 10. The temperature was raised to 180 °C and maintained at this temperature for 60 min. After the reaction, it was cooled to room temperature and filtered. The obtained filter cake was placed in a vacuum dryer at 100 °C for 8 h to obtain tobacco-stem-based hydrochar. 100 g of the tobacco-stem-based hydrochar was weighed, 10 g of liquid paraffin with a viscosity of 20 mPa·s at 20 - 60 °C was added, and then 100 g of a 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence was 98:2) and 10 g of boron nitride (flake diameter and thickness) were added and thoroughly mixed. It was stirred for 30 min to allow the hydrochar to fully adsorb the essence, and then placed in a fluidized-bed dryer. It was dried at a temperature of 40 °C and an air flow rate of 1 m / s for 10 min to obtain the tobacco-stem-based flavor-loaded granular material.

[0078] Description of the effects of the examples

[0079] The tobacco-stem-based flavor-loaded granular materials obtained in the examples and comparative examples were subjected to structural characterization and their adsorption performance for essence was tested. The results are shown in Table 1 and Table 2 and Figures 1 to 2 .

[0080] The microscopic morphology and structure of the tobacco-stem-based flavor-loaded granular material were characterized by a scanning electron microscope (SEM, Hitachi SU8220); the specific surface area and pore structure were tested using a fully automatic specific surface area and porosity analyzer (Micromeritics ASAP2020 instrument).

[0081] Adsorption efficiency calculation method: Weigh 100 g of hydrothermal carbon from tobacco stems, add a part of liquid paraffin, and after adsorbing for 60 min in a constant-temperature shaker and fully mixing with boron nitride, record the mass of the hydrothermal carbon from tobacco stems as m1 g. Then add 100 g of 2 wt% blueberry essence ethanol solution (the mass ratio of absolute ethanol to essence is 98:2), stir for 2 min to allow the hydrothermal carbon from tobacco stems to fully adsorb the essence, place it in a fluidized bed dryer and dry for 10 min, and record the hydrothermal carbon from tobacco stems as m2 g. Then the adsorption efficiency calculation formula is

[0082] Release rate calculation method: Place m2 g of the flavored particle material of tobacco stem base in a brine content measuring instrument, measure the essence release performance of the flavored particle material of tobacco stem base at a certain temperature, and record the mass of the flavored particle material of tobacco stem base at 600 s as m3. Then the essence release rate at 600 s is

[0083] Stability performance calculation method: Place m2 g of the flavored particle material of tobacco stem base in a dryer, weigh the mass of the flavored particle material of tobacco stem base after seven days and record it as m4. Then the essence loss rate after seven days is

[0084] Table 1 shows the pore structure parameters of tobacco stem raw materials and hydrothermal carbon from tobacco stems.

[0085] S BET : BET specific surface area, unit m 2 / g;

[0086] V total : Pore volume, unit cm 3 / g;

[0087] V micro / V total : Microporosity, the proportion of micropore volume in the total pore volume, unit %;

[0088] V meso / V total : Mesoporosity, the proportion of mesopore volume in the total pore volume, unit %;

[0089] Table 2 shows the adsorption and release performance of the flavored particle material of tobacco stem base in the examples and comparative examples for essence.

[0090] Table 1 Pore structure parameters of tobacco stems and hydrothermal carbon from tobacco stems

[0091]

[0092] Table 2 Adsorption and release performance of the flavored particle material of tobacco stem base for essence

[0093]

[0094]

[0095] Description of Table 1:

[0096] After hydrothermal treatment, the specific surface area of the tobacco stem raw material increased from the original 0.52 m 2 / g to 5.40 m 2 / g. The microporosity and mesoporosity increased. The specific surface areas of the tobacco stem raw material and the hydrothermal carbon of tobacco stem base were not high, far lower than 1102 m 2 / g of commercial activated carbon. And the data in Table 1 show that the tobacco stem raw material and the hydrothermal carbon of tobacco stem base mainly have macropores, while commercial activated carbon mainly has micropores and mesopores.

[0097] Description of Table 2:

[0098] The adsorption efficiency of the flavoring granule materials of tobacco stem base prepared in Examples 1 - 9 for flavor essence all exceeded 80%, the flavor release rate at 600 s was greater than 50%, and the flavor loss rate in 7 days did not exceed 50%. The adsorption efficiency of flavor essence in Example 3 was as high as 91%, the flavor release rate at 600 s was 87%, and the flavor loss rate in 7 days was 21%.

[0099] Compared with Example 3, in Comparative Example 1, solid paraffin with phase change performance was used. The viscosity of solid paraffin was relatively large, and it needed to be heated at a relatively high temperature to melt before it could be mixed with the flavoring granule materials of tobacco stem base.

[0100] Compared with Example 3, in Comparative Example 2, the tobacco stem hydrothermal carbon adsorbed flavor essence first, and then liquid paraffin was added. As a result, the flavor essence was first adsorbed into the internal pore channels of the hydrothermal carbon, and the liquid paraffin added later blocked the pore channels. Although the stability was improved, when testing the release performance, the flavor essence could not be completely released.

[0101] Compared with Example 3, in Comparative Example 3, sodium hydroxide solution was used. Due to the strong alkalinity of sodium hydroxide, the pore structure of the hydrothermal carbon was severely damaged, and the hydrothermal carbon could not form complete particles.

[0102] Compared with Example 3, in Comparative Example 4, a fixed - bed dryer was used. Its drying efficiency for materials with high viscosity was poor, and its use and maintenance costs were too high.

[0103] Compared with Example 3, in Comparative Example 5, the liquid paraffin used was physically mixed with the hydrothermal carbon without an adsorption process. Then the liquid paraffin did not play a role in assisting the adsorption of flavor essence, and blocked its pore structure, reducing the specific surface area and resulting in a decrease in adsorption performance.

[0104] In summary, the flavoring granule materials of tobacco stem base described by the method of the present invention all showed significantly better adsorption performance than Comparative Examples 1 - 5 in the application of adsorbing flavor essence.

[0105] Figure 1It is the scanning electron microscope image of the tobacco stem-based flavoring particle material prepared in Example 3 of the present invention. It can be seen that it is a three-dimensional structure composed of loose lamellae, with an open framework and abundant pores.

[0106] Figure 2 It is the nitrogen adsorption-desorption curve and pore size distribution curve of the tobacco stem-based flavoring particle material prepared in Example 3 of the present invention. Its nitrogen adsorption-desorption curve shows the characteristics of a type II adsorption isotherm, indicating that the tobacco stem-based flavoring particle material is mainly a macroporous structure. The pore size distribution curve shows that its micropores are concentrated at 2 nm, mesopores are concentrated at 10 nm, and macropores are concentrated at 50-100 nm.

[0107] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a tobacco stem-based flavoring granule material, characterized in that, It includes the following steps: (1) Hydrothermally react tobacco stems in a potassium-based alkaline brine solution to obtain tobacco-stem-based hydrochar; (2) Adsorb liquid paraffin on the tobacco-stem-based hydrochar at 60 - 80 °C, then mix it evenly with an essence ethanol solution and highly thermally conductive nanosheets at 40 °C or below, and finally dry it in a fluidized bed dryer to obtain a tobacco-stem-based hydrochar essence-loaded material.

2. The preparation method of a tobacco stem-based flavoring particle material according to claim 1, wherein In step (2), the mass ratio of the tobacco-stem-based hydrochar, liquid paraffin, essence ethanol solution, and highly thermally conductive nanosheets is 100:(5 - 20):100:(2 - 20); and / or, the boiling point of the liquid paraffin in step (2) is higher than 300 °C, and its viscosity at 20 - 60 °C is 10 - 30 mPa·s; and / or, the mass concentration of the essence in the essence ethanol solution in step (2) is 2 - 10 wt%; and / or, the essence in step (2) is a plant-based liquid essence soluble in absolute ethanol; and / or, the highly thermally conductive nanosheets in step (2) are one of boron nitride, aluminum nitride, and silicon carbide; and / or, the size of the highly thermally conductive nanosheets in step (2) is such that the sheet diameter is greater than 0.5 - 2 μm and the thickness is 2 - 10 nm.

3. The preparation method of a tobacco stem-based flavoring granule material according to claim 1, characterized in that The time for the tobacco-stem-based hydrochar to adsorb liquid paraffin at 60 - 80 °C in step (2) is 60 - 120 minutes; and / or, the mixing temperature of the tobacco-stem-based hydrochar, essence ethanol solution, and highly thermally conductive nanosheets in step (2) is 25 - 40 °C, and the time is 30 - 120 minutes; and / or, the air flow rate of the fluidized bed dryer in step (2) is 0.5 - 2 m / s; the drying temperature is 30 - 60 °C; the drying time is 10 - 30 minutes.

4. The preparation method of a tobacco stem-based flavoring granule material according to claim 2, characterized in that, In step (2), the mass ratio of the tobacco-stem-based hydrochar, liquid paraffin, essence ethanol solution, and highly thermally conductive nanosheets is 100:(10 - 15):100:(5 - 10); and / or, the essence in step (2) is at least one of sweet orange essence and blueberry essence.

5. The preparation method of a tobacco stem-based flavoring granule material according to claim 1, characterized in that, In the potassium-based alkaline brine solution in step (1), the potassium-based alkaline salt is at least one of KOH, K2CO3, and KHCO3; and / or, the pH of the potassium-based alkaline brine solution in step (1) is 10 - 13; and / or, the temperature of the hydrothermal reaction in step (1) is 150 - 210 °C, and the heat preservation time is 30 - 90 min; and / or, the mesh number of the tobacco stems in step (1) is 30 - 80 mesh.

6. The preparation method of a tobacco stem-based flavoring granule material according to claim 5, characterized in that, The temperature of the hydrothermal reaction in step (1) is 180 - 200 °C, and the heat preservation time is 60 - 90 min; and / or, the mesh number of the tobacco stems in step (1) is 30 - 50 mesh.

7. The preparation method of a flavoring particle material based on tobacco stems according to any one of claims 1 to 6, characterized in that, It includes the following steps: (1) Add tobacco stems to water, then add a potassium-based alkaline regulator to adjust the pH value to 10 - 13, conduct a hydrothermal reaction, cool to room temperature, filter, wash with water, and dry to obtain tobacco-stem-based hydrochar; (2) Adsorb the tobacco-stem-based hydrochar and liquid paraffin at 60 - 80 °C for 60 - 120 minutes, then mix it evenly with an essence ethanol solution and highly thermally conductive nanosheets at 40 °C or below, and finally dry it in a fluidized bed dryer to obtain a tobacco-stem-based hydrochar essence-loaded material.

8. The preparation method of a tobacco stem-based flavoring particle material according to claim 7, characterized in that, In step (1), the mass ratio of the tobacco stems to water is 1:(5 - 20); And / or, the potassium-based alkaline regulator described in step (1) is an aqueous solution with a mass concentration of 10-20%, and the solute therein is a potassium-based alkaline salt, specifically at least one of KOH, K2CO3, and KHCO3.

9. A tobacco stem-based flavoring particle material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the tobacco stem-based flavoring particle material according to claim 9.

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