A method for recycling tobacco waste extraction residue

Abstract

The application discloses a recycling method of tobacco waste powder extraction waste residue, comprising the following operation steps: S1, first, tobacco essential oil is extracted from tobacco waste powder by using a supercritical carbon dioxide extraction method, and extraction waste residue is collected; S2, the collected extraction waste residue is mixed with an alkaline solution, and then poured into a high-pressure reaction kettle to perform a hydrothermal carbonization reaction; S3, after the reaction kettle returns to a normal temperature and pressure state, the product in the reaction kettle is poured out and filtered and dried, the obtained solid product is biochar, and the liquid product is collected and stored in a specific anaerobic cool environment for a period of time, and then organic fertilizer is obtained. The method can realize effective recycling of tobacco waste by using hydrothermal liquefaction to process the waste residue after supercritical extraction of the tobacco waste powder.

Description

Technical Field

[0001] This application relates to the field of tobacco waste recycling technology, and in particular to a method for recycling tobacco waste extraction residue. Background Technology

[0002] Nearly 30% of tobacco waste and byproducts are generated during the harvesting and production process and cannot be used. Advanced supercritical fluid extraction and other methods can effectively extract nicotine, solanine, and other aroma components to produce cigarette flavorings, enabling the recycling of waste tobacco. However, the extraction residue remaining after extraction is the main waste product of this process, and its large quantity requires rapid and proper disposal to avoid environmental pollution.

[0003] Common methods for treating plant extraction waste mainly include landfilling and returning it to the field or preparing solid fuel. Due to the special characteristics of plants like tobacco, their extraction waste usually still contains a large amount of nitrogen-containing organic components. Blindly landfilling it to the field can lead to possible changes in soil structure, and the harmful components can seep into groundwater, polluting water sources and causing serious environmental pollution. When burned directly as fuel, it produces a large amount of nitrogen oxides, polluting the atmosphere. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for recycling tobacco waste extraction residue. The method uses hydrothermal liquefaction to treat the residue after supercritical extraction of tobacco waste, thereby achieving effective recycling of tobacco waste.

[0005] The technical solution provided by this invention is as follows:

[0006] A method for recycling tobacco waste extraction residue includes the following steps:

[0007] S1. First, tobacco essential oil is extracted from tobacco waste using supercritical carbon dioxide extraction, and the extraction residue is collected.

[0008] S2. The collected extraction waste residue is mixed with an alkaline solution and then poured into a high-pressure reactor for hydrothermal carbonization reaction.

[0009] S3. After the reactor returns to normal temperature and pressure, pour out the product from the reactor, filter and dry it. The resulting solid product is biochar. The liquid product is collected and stored in a specific anaerobic cool environment for a period of time to obtain organic fertilizer.

[0010] Preferably, step S3 is followed by step S4, in which the organic fertilizer is further dissolved to prepare a water-soluble fertilizer.

[0011] Preferably, step S3 is followed by step S5, in which biochar and organic fertilizer are mixed and further fermented to prepare recycled compost.

[0012] Preferably, in step S1, anhydrous ethanol is added as an entrainer during the supercritical carbon dioxide extraction process, and the amount of anhydrous ethanol used is 5-10% of the mass of tobacco waste.

[0013] Preferably, the pH value of the alkaline solution in step S2 is 8 to 10.

[0014] Preferably, the alkaline solution in step S2 is a 5% Na2CO3 aqueous solution, a sodium bicarbonate solution, or a sodium hydroxide solution.

[0015] Preferably, the mass ratio of extraction waste residue to alkaline solution in step S2 is 5:1 to 7:1.

[0016] Preferably, in step S2, the temperature of the hydrothermal reaction is 150–250°C, the pressure inside the reactor is 2–6 MPa, and the reaction time is 1–1.5 h.

[0017] Preferably, in step S2, a hydrothermal reaction temperature higher than 200°C and a pressure exceeding 3.5 MPa in the reactor will promote the formation of more solid products, while a lower temperature will generate more liquid products. The hydrothermal temperature and the pressure in the reactor can be adjusted according to production needs to achieve the production target requirements.

[0018] Preferably, the storage time in step S3 is 20 to 25 days.

[0019] This application has the following advantages over the prior art:

[0020] The method of this application transforms the residue remaining after tobacco waste extraction into biochar and organic fertilizer through hydrothermal liquefaction. This process converts the previously unusable residue, which was of low quality, into biochar and organic fertilizer. Further processing of these two materials produces various waste products that can be reused in tobacco cultivation. This effectively achieves resource recycling of waste, improves soil fertility, reduces economic costs, and significantly reduces carbon emissions throughout the entire life cycle of tobacco production, contributing to achieving carbon peaking and carbon neutrality goals. By controlling reaction parameters, the ratio of biochar to organic fertilizer obtained can be effectively adjusted to meet actual production needs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a process flow diagram of the method for recycling tobacco waste residue from extraction in an embodiment of the present invention. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Example 1:

[0025] like Figure 1 As shown in the figure, this invention provides a method for recycling tobacco waste extraction residue, comprising the following steps:

[0026] S1. First, tobacco essential oil is extracted from tobacco waste using supercritical carbon dioxide extraction. After extraction, the extraction residue is poured out of the extraction tank and collected to obtain the extraction residue.

[0027] S2. The collected extraction waste residue is mixed with an alkaline solution and then poured into a high-pressure reactor for hydrothermal carbonization. The alkaline environment is conducive to the hydrolysis of organic matter and accelerates the reaction rate.

[0028] S3. After the reactor returns to normal temperature and pressure, pour out the product from the reactor, filter and dry it. The resulting solid product is biochar. The liquid product is collected and stored in a specific anaerobic cool environment for 20-25 days to obtain organic fertilizer. Since tobacco contains a high proportion of nitrogen, there is no need to supplement nitrogen during the composting process. The nitrogen is converted into nutrients needed by plants, and the nitrogen that is difficult to deal with by burning or direct landfill is converted into usable plant nutrients.

[0029] The method for recycling tobacco waste extraction residue in this embodiment uses supercritical carbon dioxide extraction to extract tobacco essential oil from tobacco waste. Compared with traditional chemical extraction methods, it reduces the environmental pollution caused by the large-scale use of chemical solvents. By adjusting the pressure and temperature of carbon dioxide to control its state, the separation of extraction residue from extraction solvent is easily achieved. Almost no organic solvent remains in the extraction residue, making it easy to collect and utilize the extraction residue directly.

[0030] In this embodiment, anhydrous ethanol is added as an entrainer during the supercritical carbon dioxide extraction process in step S1. The amount of anhydrous ethanol used is 5-10% of the mass of tobacco waste. Preferably, the amount of hydroethanol used is 8% of the mass of tobacco waste.

[0031] In this embodiment, the pH value of the alkaline solution in step S2 is 8-10 (preferably pH=9). The alkaline solution is a 5% concentration of Na2CO3 aqueous solution, sodium bicarbonate solution, or sodium hydroxide solution. The mass ratio of extraction waste residue to alkaline solution is 5:1-7:1 (preferably, the mass ratio of extraction waste residue to alkaline solution is 6:1). The hydrothermal reaction temperature is 150-250℃, the pressure inside the reactor is 2-6MPa, and the reaction time is 1-1.5h. The temperature and pressure of the hydrothermal reaction affect the relative proportions of biochar and organic fertilizer in the product. A hydrothermal reaction temperature above 200℃ and a pressure inside the reactor exceeding 3.5MPa will promote the formation of more solid-phase products, while lower temperatures will produce more liquid-phase products. The hydrothermal temperature and the pressure inside the reactor can be adjusted according to production needs to achieve the production target requirements.

[0032] Example 2:

[0033] like Figure 1 As shown, the difference between this embodiment and embodiment 1 is that: after step S3, there is also operation step S4, which further dissolves the organic fertilizer to prepare water-soluble fertilizer to meet the needs of soil improvement.

[0034] Example 3:

[0035] like Figure 1 As shown, the difference between this embodiment and Embodiment 1 is that: Figure 1 As shown, after step S3, there is also operation step S5, which involves mixing biochar and organic fertilizer and then further fermenting them to prepare recycled compost.

[0036] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for recycling tobacco waste fines extraction waste residues, characterized in that, The method comprises the following steps: S1, tobacco essential oil is extracted from tobacco waste by supercritical carbon dioxide extraction, and extraction residues are collected; S2, the collected extraction residues are mixed with an alkaline solution, and then poured into a high-pressure reaction kettle for hydrothermal carbonization, the alkaline solution is a Na2CO3 aqueous solution, a sodium bicarbonate solution or a sodium hydroxide solution; S3, after the reaction kettle returns to normal temperature and pressure, the product in the reaction kettle is poured out and filtered and dried, the obtained solid product is biochar, the liquid product is collected and stored in a specific anaerobic cool environment for a period of time to obtain organic fertilizer; S4, the organic fertilizer is further dissolved to prepare water-soluble fertilizer; S5, the biochar and the organic fertilizer are mixed and further fermented to prepare regenerated compost.

2. The method for recycling tobacco waste- fines extraction waste residue according to claim 1, characterized in that, In the step S1, anhydrous ethanol is added as an entrainer in the supercritical carbon dioxide extraction process, and the amount of anhydrous ethanol is 5-10% of the mass of the tobacco waste.

3. The method according to claim 1, wherein In the step S2, the pH value of the alkaline solution is 8-10.

4. The method for recycling tobacco waste- fines extraction waste residue according to claim 1, characterized in that, In the step S2, the concentration of the alkaline solution is 5%.

5. The tobacco waste fines extraction waste residue recycling method according to claim 1, characterized by, In the step S2, the mass ratio of the extraction residues to the alkaline solution is 5:1-7:

1.

6. The method for recycling tobacco waste fines extraction waste residue according to any one of claims 1-5, characterized in that, In the step S2, the temperature of the hydrothermal reaction is 150-250℃, the pressure in the reaction kettle is 2-6MPa, and the reaction time is 1-1.5h.

7. The method according to any one of claims 1 to 5, wherein the tobacco waste fines extraction waste residue is recycled by, In the step S2, when the temperature of the hydrothermal reaction is higher than 200℃ and the pressure in the reaction kettle is higher than 3.5MPa, more solid products are generated, otherwise more liquid products are generated, and the hydrothermal temperature and the pressure in the reaction kettle can be adjusted according to the production requirements to achieve the production target requirements.

8. The method for recycling tobacco waste fines extraction waste residue according to any one of claims 1-5, characterized in that, In the step S3, the storage time is 20-25 days.

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