High fuel property tea carbon briquette fuel having tea aroma and method for preparing the same

Abstract

The application discloses a high-fuel-property tea carbon briquette with tea aroma and a preparation method thereof, and belongs to the technical field of fuel preparation. In the preparation, old leaves and branches on tea tree branches are separated, and are treated by two times of fixation; during the fixation, tea aroma solution is collected by condensing tail gas; the old leaves and branches after the second fixation are treated by gasification to obtain tea carbon and tea tar; the tea tar is separated by vacuum distillation to obtain light phenol solution and heavy substance solution; the heavy substance solution is dried to obtain heavy substance solid, which is mixed with the tea carbon to obtain carbon powder; a glue is obtained by adding the light phenol solution, polyvinyl methyl ethylene glycol, starch, polycondensation and gelatinization reaction with a sodium hydroxide solution as a solvent; and the carbon powder, the glue, the tea aroma solution and water are mixed and formed to obtain the briquette. The preparation method realizes high-value utilization of waste pruned tea tree branches, and the obtained briquette has the characteristics of tea aroma, high calorific value, low ignition point and long combustion time.

Description

Technical Field

[0001] This invention relates to the field of fuel preparation technology, and more specifically to a tea charcoal briquettes fuel with high fuel properties and a tea aroma, and its preparation method. Background Technology

[0002] Biomass energy is a very important type of clean energy and energy conservation and environmental protection. Due to its renewable nature, abundant resources, and environmental friendliness, biomass energy has become the world's fourth largest energy source and the only clean and renewable energy source that can be transported and stored. It mainly utilizes modern biomass energy technology to process raw materials such as agricultural waste, logging residues, livestock and poultry manure, municipal solid waste, domestic sewage, and industrial organic wastewater into end products such as biomass pellet fuel, biodiesel, and bioethanol.

[0003] Biomass briquettes are made primarily from agricultural and forestry residues. They are produced through processes such as slicing, crushing, impurity removal, refining, screening, mixing, softening, conditioning, extrusion, drying, cooling, quality inspection, and packaging. The resulting briquettes are environmentally friendly and have high calorific value and complete combustion.

[0004] Biomass gasification power generation technology, which co-produces charcoal, heat, and fertilizer, can use pruned tea tree branches as raw materials. Through pyrolysis and gasification, these branches are simultaneously converted into combustible gas, biochar, and tar. The biochar is mostly sold as a primary product, such as industrial charcoal, with a market value ranging from hundreds to thousands of yuan per ton. However, converting biochar into high-value-added products such as pulverized charcoal and activated carbon can not only increase expected profit returns but also realize the potential commercial value of biochar. Tar, a gasification byproduct, is a brown, viscous mixture mainly composed of phenols and other substances. Its high acidity, complex composition, and high water content make it difficult to utilize.

[0005] Furthermore, tea is a key economic crop in China. In 2021, the total tea garden area in major tea-producing provinces of my country was 48.96 million mu, with a harvested area of ​​43.75 million mu. However, pruning during the harvest season generates a large amount of branch waste. While the total amount of pruned tea branches as a timber resource is considerable, how to utilize them is a question worthy of in-depth research. In existing technologies, the use of branch waste to prepare molded fuel suffers from low calorific value and high ignition point. Summary of the Invention

[0006] To address the above problems, this invention provides a tea charcoal briquettes fuel with high fuel properties and a tea aroma, as well as a method for preparing the same. This not only improves the utilization rate of tea branches, but also produces a briquettes fuel with high calorific value, low ignition point, long burning time, no smoke, and a tea aroma.

[0007] The first objective of this invention is to provide a method for preparing tea charcoal briquettes with high fuel properties and a tea aroma, comprising the following steps:

[0008] Step 1: Separate the old leaves and branches from the pruned tea tree branches, and perform fixation at 175-180℃. Then, lower the temperature to 135-140℃ and introduce steam for a second fixation process. During fixation, condense the exhaust gas to collect the tea aroma solution.

[0009] Step 2: The old leaves and branches after the second fixation in Step 1 are gasified to obtain tea charcoal and tea tar. The tea tar is separated by vacuum distillation to obtain a light phenol solution and a heavy substance solution. The heavy substance solution is dried to obtain a heavy substance solid, which is then mixed with tea charcoal to obtain charcoal powder.

[0010] Step 3: Using sodium hydroxide solution as a solvent, add light phenol solution, polyvinyl acetal, and starch to undergo condensation and gelatinization reactions to obtain an adhesive;

[0011] Step 4: Mix the charcoal powder, adhesive, tea flavoring solution and water, and cold press to obtain molded fuel.

[0012] Preferably, in step 1, when blanching, the blanching speed for old leaves is 1kg / 15-17min, and the blanching speed for branches is 1kg / 25-28min.

[0013] When processing tea leaves for the second time, the processing speed for older leaves is 1 kg / 5-7 min, and the processing speed for branches and stems is 1 kg / 10-13 min.

[0014] Preferably, in step 2, the gasification temperature is 600-700℃, the gasification time is 30-40 min, and the mass ratio of old leaves to branches is 1:1.5-2.

[0015] Preferably, the vacuum distillation temperature is 170-180℃ and the time is 1kg / 10-15min.

[0016] Preferably, the drying temperature of the heavy substance solution is 80-85℃;

[0017] The tea charcoal is pulverized to 0.075-0.15mm and mixed with heavy solid materials. The mass ratio of tea charcoal to heavy solid materials is 1:0.5-0.9.

[0018] Preferably, in step 3, the mass ratio of the light phenolic solution, polyvinyl acetal, sodium hydroxide, and starch is 1:0.88-0.93:0.2-0.4:0.27-0.35; the sodium hydroxide solution is a 35% sodium hydroxide solution by mass.

[0019] Polyvinyl methyl acetal includes polyvinyl methyl acetal I and polyvinyl methyl acetal II. Polyvinyl methyl acetal I accounts for 85% of the total mass of polyvinyl methyl acetal, and polyvinyl methyl acetal II accounts for 15% of the total mass of polyvinyl methyl acetal.

[0020] Preferably, the adhesive synthesis step in step 3 is as follows: sodium hydroxide is mixed with water to obtain a sodium hydroxide solution with a mass fraction of 35%, which is then set aside.

[0021] Add a light phenol solution to a sodium hydroxide solution and stir until homogeneous at 40-43°C. Then add polyvinyl methyl aldehyde I within 30 minutes and raise the temperature to 88-90°C. Raise the temperature to 95-97°C within 20 minutes and maintain this temperature for 15-17 minutes. Lower the temperature to 85-87°C and add polyvinyl methyl aldehyde II. Raise the temperature again to 95-97°C and maintain this temperature for 10-13 minutes. Lower the temperature to 55-58°C, add starch, and gelatinize for 15-18 minutes. Finally, cool to room temperature to obtain the adhesive.

[0022] Preferably, in step 4, the mass ratio of charcoal powder, adhesive, tea flavoring solution, and water is 1:0.12-0.15:0.15-0.2:0.2.

[0023] Preferably, the synthesis step of the molded fuel is as follows: mixing the adhesive with water to obtain an adhesive solution;

[0024] Charcoal powder is loaded into a tubular mixer, adhesive aqueous solution and tea aroma solution are loaded into a spray gun, and then loaded into a prototype mold for cold pressing at 20-25 MPa. It is then dried and cured at 105-107℃ to obtain shaped fuel.

[0025] The second objective of this invention is to provide a tea charcoal briquettes with high fuel properties and a tea aroma prepared by the above-described preparation method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] Tender leaves from tea trees can be used to produce tea, which is processed through high-temperature fixation and other techniques. During this process, light non-terpenes and heavy terpenes release volatile components, which are the main source of tea aroma. Older leaves from pruned branches have similar chemical structures to tender leaves, but cannot be used to produce tea. Therefore, this invention uses high-temperature treatment of old leaves and branches from discarded tea trees to obtain terpenes and other aroma compounds. Furthermore, the fixation process deoxygenates the tea branches and increases their carbon-hydrogen ratio, thus raising their initial calorific value. After fixation, the high temperature destroys and deactivates the oxidase activity in the fresh leaves, inhibiting the enzymatic oxidation of tea polyphenols and other compounds that form aroma compounds. These compounds have high oxygen content and are easily volatilized by heat, undergoing a deoxygenation reaction.

[0028] Compared to direct gasification of tea tree branches, gasification after the initial fixation process results in tea charcoal with a higher carbon-to-hydrogen ratio, porosity, and calorific value, leading to better combustion performance. This process also increases the content of low-molecular-weight phenolic substances in the tea tar and retains some of the theophylline from the tea tree. The tea tar is then separated into light phenolic substances and heavy substances through vacuum distillation. The light phenolic substances are reacted with polyvinyl methyl aldehyde, starch, and sodium hydroxide solution to prepare a phenolic adhesive via a condensation gelatinization reaction. The heavy substances are added to the tea charcoal to increase its calorific value, lower its combustion temperature, and delay its combustion time. Through the use of the adhesive, tea charcoal, heavy theophylline, and tea aroma compounds, a tea charcoal briquettes with high energy density, high calorific value, low ignition point, long combustion time, and a smokeless, tea-fragrant aroma can be obtained, achieving high-value utilization of waste pruned tea tree branches.

[0029] While improving the utilization rate of discarded tea tree branches, it also improves economic benefits. The original tea tree pruning waste gasification char was sold on the market for 1,000 yuan / ton as reducing char. Now, the cost of adhesive required for one ton of char is calculated to be 600 yuan, and the market price of briquetted fuel is 2,000-4,000 yuan. The actual profit can be 1,500-3,000 yuan / ton. Attached Figure Description

[0030] Figure 1 The tea charcoal briquettes prepared in Example 1;

[0031] Figure 2 Here is a GCMS image of theophylline in the heavy material prepared in Example 1;

[0032] Figure 3 The image shows the GC-MS chromatogram of phenol in the light phenol solution prepared in Example 1.

[0033] Figure 4 The image shows the GC-MS image of o-cresol in the light phenol solution prepared in Example 1.

[0034] Figure 5 The image shows the GCMS of intermediate cresol in the light phenol solution prepared in Example 1.

[0035] Figure 6 Here is the GCMS image of guaiacol in the light phenolic solution prepared in Example 1;

[0036] Figure 7 The image shows the GC-MS chromatogram of dimethylphenol in the light phenol solution prepared in Example 1.

[0037] Figure 8 The image shows the GC-MS chromatogram of methoxycresol in the light phenol solution prepared in Example 1.

[0038] Figure 9The image shows the GCMS plot of 4-ethyl-2-methoxyphenol in the light phenol solution prepared in Example 1.

[0039] Figure 10 The image shows the GCMS image of 4-vinyl-2-methoxyphenol in the light phenol solution prepared in Example 1.

[0040] Figure 11 The dimethoxyphenol in the light phenol solution prepared in Example 1;

[0041] Figure 12 Here is the GCMS image of isoeugenol in the light phenol solution prepared in Example 1;

[0042] Figure 13 The image shows the GCMS image of 2-methoxy-4-propyl-phenol in the light phenol solution prepared in Example 1. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] Step 1: Separate the old leaves from the branches of the pruned tea tree. Set the rotary kiln temperature to 180℃ and kill the old leaves and branches separately. The killing speed for old leaves is 1 kg / 15 min, and the killing speed for branches is 1 kg / 25 min. Then, lower the rotary kiln temperature to 140℃ and pass steam to kill the old leaves and branches a second time. The killing speed for old leaves is 1 kg / 5 min, and the killing speed for branches is 1 kg / 10 min. During this process, the exhaust gas is condensed and the tea aroma solution is collected. GCMS characterization shows that the tea aroma solution contains geraniol, linalool, cis-3-hexen-1-ol, etc., which have a tea aroma, as shown in Table 1.

[0046] Step 2: After the second withering, the old leaves and branches are vaporized at 700℃ for 30 minutes at a mass ratio of 1:2 to obtain 35 wt.% tea charcoal and 20 wt.% tea tar. By setting the vacuum distillation temperature to 170℃ and the time to 1 kg / 10 min, the light phenols such as phenol and cresol in the tea tar are separated from the heavy substances such as theophylline, resulting in a light yellowish-brown light phenol solution and a dark brown viscous heavy substance solution; Figure 2 As shown in Table 2, qualitative analysis by GCMS revealed that the heavy substances were incompletely carbonized materials such as theophylline and lignin fragment condensates; Figure 3-13As shown in Table 3, qualitative and quantitative analysis by GCMS revealed that the light phenol solution mainly contained cresol, phenol, and other small molecule acids, esters, and water, with phenolic substances accounting for 25%.

[0047] The heavy substance solution is dried at 80℃, and the viscous liquid is turned into a solid state, which is recorded as the heavy substance solid. The tea charcoal is pulverized at high speed to 0.075-0.15mm and mixed with the heavy substance solid at a mass ratio of 1:0.5 to form charcoal powder, and then dried at 105℃ for 2 hours.

[0048] Step 3: Prepare adhesive for molded fuel

[0049] The mass ratio of light phenolic solution, polyvinyl methyl aldehyde, sodium hydroxide, and starch is 1:0.88:0.2:0.27. Polyvinyl methyl aldehyde comprises polyvinyl methyl aldehyde I and polyvinyl methyl aldehyde II, with polyvinyl methyl aldehyde I accounting for 85% of the total mass of polyvinyl methyl aldehyde and polyvinyl methyl aldehyde II accounting for 15%. A 35% sodium hydroxide solution is prepared by mixing sodium hydroxide with water and set aside.

[0050] A light phenol solution and sodium hydroxide solution were added to a 500 mL three-necked flask equipped with an electric stirrer, thermometer, and reflux condenser (attached to a dropping funnel). The mixture was stirred at 40 °C, then heated to 88 °C. During the heating process, polyvinyl methyl aldehyde I was added continuously over 30 minutes. The temperature was then slowly increased to 95 °C over 20 minutes and held for 16 minutes. The temperature was then lowered to 85 °C, and polyvinyl methyl aldehyde II was continuously added. The temperature was then increased to 95 °C and held for 10 minutes, followed by a decrease to 55 °C. Starch was added and gelatinized for 15 minutes. Finally, the mixture was cooled to room temperature with water to obtain the molded fuel adhesive (solid content: 55%, viscosity: 80 mPa·s).

[0051] Step 4: The mass ratio of charcoal powder, adhesive, tea-scented solution, and water is 1:0.12:0.15:0.2. Mix 120g of adhesive with 200g of water to obtain an adhesive solution.

[0052] 1 kg of charcoal powder was loaded into a tubular mixer, 320 g of adhesive aqueous solution and 150 g of tea-scented solution were loaded into a spray gun (applying rate 50 ml / min), and then loaded into a prototype mold. The mixture was then cold-pressed at 20 MPa using a variable-diameter screw extrusion molding machine. After molding, the moisture and adhesive were dried and cured at 105℃ to obtain the molded fuel. Figure 1 As shown.

[0053] Table 1. Identification results of the main components of the tea-flavored solution.

[0054]

[0055]

[0056] Table 2. Identification results of theophylline

[0057] SI CompoundName RT / min Cas# Probability 897 Caffeine 18.54 58-08-2 96.14 902 Caffeine 18.54 58-08-2 96.14 909 Caffeine 18.54 58-08-2 96.14

[0058] Table 3. Identification results of the main components of the phenolic solution.

[0059]

[0060]

[0061] Example 2

[0062] Step 1: Separate the old leaves from the branches of the pruned tea tree. Set the rotary kiln temperature to 175℃ and fix the old leaves and branches separately. The fixation speed for the old leaves is 1kg / 17min, and the fixation speed for the branches is 1kg / 28min. Then, lower the rotary kiln temperature to 135℃ and pass steam to fix the old leaves and branches a second time. The fixation speed for the old leaves is 1kg / 7min, and the fixation speed for the branches is 1kg / 13min. During this process, the exhaust gas is condensed and the tea aroma solution is collected.

[0063] Step 2: After the second blanching, the old leaves and branches are vaporized at 600℃ for 40 minutes at a mass ratio of 1:2 to obtain tea charcoal and tea tar. By setting the vacuum distillation temperature to 180℃ and the time to 1kg / 13min, the light phenols such as phenol and cresol in the tea tar are separated from the heavy substances such as theophylline, resulting in a light yellow-brown light phenol solution and a dark brown viscous heavy substance solution.

[0064] The heavy substance solution was dried at 85℃, and the viscous liquid was transformed into a solid state, which was recorded as the heavy substance solid. The tea charcoal was pulverized at high speed to 0.075-0.15mm and mixed with the heavy substance solid at a mass ratio of 1:0.9 to form charcoal powder, which was then dried at 105℃ for 2 hours.

[0065] Step 3: Prepare adhesive for molded fuel

[0066] The mass ratio of light phenolic solution, polyvinyl methyl aldehyde, sodium hydroxide, and starch is 1:0.93:0.3:0.30. Polyvinyl methyl aldehyde comprises polyvinyl methyl aldehyde I and polyvinyl methyl aldehyde II, with polyvinyl methyl aldehyde I accounting for 85% of the total mass of polyvinyl methyl aldehyde and polyvinyl methyl aldehyde II accounting for 15%. A 35% sodium hydroxide solution is prepared by mixing sodium hydroxide with water and set aside.

[0067] A light phenol solution and sodium hydroxide solution were added to a 500 mL three-necked flask equipped with an electric stirrer, thermometer, and reflux condenser (attached to a dropping funnel). The mixture was stirred at 43°C, then heated to 90°C. During the heating process, polyvinyl methyl aldehyde I was added continuously over 30 minutes. The temperature was then slowly increased to 97°C over 20 minutes and held for 17 minutes. The temperature was then lowered to 87°C, and polyvinyl methyl aldehyde II was continuously added. The temperature was then increased to 97°C and held for 13 minutes, followed by a decrease to 58°C. Starch was added and gelatinized for 18 minutes. Finally, the mixture was cooled to room temperature with water to obtain the molded fuel adhesive.

[0068] Step 4: The mass ratio of charcoal powder, adhesive, tea-scented solution, and water is 1:0.15:0.2:0.2. Mix 150g of adhesive with 200g of water to obtain an adhesive solution.

[0069] 1 kg of charcoal powder was loaded into a tubular mixer, 350 g of adhesive aqueous solution and 200 g of tea aroma solution were loaded into a spray gun (applying rate 50 ml / min), and then loaded into a prototype mold and cold-pressed at 23 MPa by a variable diameter screw extrusion molding machine. After molding, the moisture and adhesive were dried at 107℃ and cured to obtain molded fuel.

[0070] Example 3

[0071] Step 1: Separate the old leaves from the branches of the pruned tea tree. Set the rotary kiln temperature to 177℃ and fix the old leaves and branches separately. The fixation speed for the old leaves is 1kg / 16min, and the fixation speed for the branches is 1kg / 27min. Then, lower the rotary kiln temperature to 137℃ and pass steam to fix the old leaves and branches a second time. The fixation speed for the old leaves is 1kg / 6min, and the fixation speed for the branches is 1kg / 11min. During this process, the exhaust gas is condensed and the tea aroma solution is collected.

[0072] Step 2: After the second blanching, the old leaves and branches are vaporized at 650℃ for 35 minutes at a mass ratio of 1:1.8 to obtain tea charcoal and tea tar. By setting the vacuum distillation temperature to 175℃ and the time to 1kg / 15min, the light phenols such as phenol and cresol in the tea tar are separated from the heavy substances such as theophylline, resulting in a light yellow-brown light phenol solution and a dark brown viscous heavy substance solution.

[0073] The heavy substance solution was dried at 83℃, and the viscous liquid was transformed into a solid state, which was recorded as the heavy substance solid. The tea charcoal was pulverized at high speed to 0.075-0.15mm and mixed with the heavy substance solid at a mass ratio of 1:0.7 to form charcoal powder, which was then dried at 105℃ for 2 hours.

[0074] Step 3: Prepare adhesive for molded fuel

[0075] The mass ratio of light phenolic solution, polyvinyl methyl aldehyde, sodium hydroxide, and starch is 1:0.9:0.4:0.35. Polyvinyl methyl aldehyde comprises polyvinyl methyl aldehyde I and polyvinyl methyl aldehyde II, with polyvinyl methyl aldehyde I accounting for 85% of the total mass of polyvinyl methyl aldehyde and polyvinyl methyl aldehyde II accounting for 15%. A 35% sodium hydroxide solution is prepared by mixing sodium hydroxide with water and set aside.

[0076] A light phenol solution and sodium hydroxide solution were added to a 500 mL three-necked flask equipped with an electric stirrer, thermometer, and reflux condenser (attached to a dropping funnel). The mixture was stirred at 41 °C, then heated to 89 °C. During the heating process, polyvinyl methyl aldehyde I was added, continuing for 30 minutes. The temperature was then slowly increased to 96 °C over 20 minutes and held for 15 minutes. The temperature was then lowered to 86 °C, and polyvinyl methyl aldehyde II was continuously added. The temperature was then increased to 96 °C and held for 11 minutes, followed by a decrease to 56 °C. Starch was added and gelatinized for 16 minutes. Finally, the mixture was cooled to room temperature with water to obtain the molded fuel adhesive.

[0077] Step 4: The mass ratio of charcoal powder, adhesive, tea-scented solution, and water is 1:0.13:0.17:0.2. Mix 130g of adhesive with 200g of water to obtain an adhesive solution.

[0078] 1 kg of charcoal powder was loaded into a tubular mixer, 330 g of adhesive aqueous solution and 170 g of tea aroma solution were loaded into a spray gun (applying rate 50 ml / min), and then loaded into a prototype mold and cold-pressed at 25 MPa by a variable diameter screw extrusion molding machine. After molding, the moisture and adhesive were dried at 106℃ and cured to obtain molded fuel.

[0079] Comparative Example 1

[0080] Similar to Example 1, except that the old leaves and branches are not subjected to blanching treatment to prepare shaped fuel.

[0081] Referring to GB / T 17664-1999 "Charcoal and Test Methods", GB / T476-2001 "Elemental Analysis Methods for Coal", DB11 / T 541-2008 "Biomass Briquetting Fuel", ZDHW-8A microcomputer calorimeter, and Shimadzu TG analyzer, the charcoal powder moisture content, ash content, volatile matter, fixed carbon content, elemental analysis, briquetted charcoal strength, and calorific value were determined (the average value of three measurements was taken).

[0082] Table 4 Comprehensive Combustion Characteristic Index of Molded Fuels

[0083]

[0084]

[0085] As shown in Table 4, compared to Comparative Example 1, the initial calorific value of the old leaves and branches after the fixation treatment was improved due to deoxidation and an increased C-H ratio. Compared to the direct gasification of the old leaves and branches of the tea tree, the tea charcoal obtained by gasification after fixation treatment has a higher C-H ratio, porosity, and calorific value, resulting in better combustion performance.

[0086] The process of killing the green (or not killing the green) increases the carbon-hydrogen ratio of the raw materials and reduces the oxygen content, thereby increasing the calorific value and burnout temperature of the shaped fuel, lowering its ignition point, making it easier to ignite and increasing its combustion rate and burning time. Killing the green further reduces the moisture content, making it easier to preserve. Killing the green can also collect tea aroma substances, making tea-flavored shaped fuel, which enhances its external quality and selling points.

[0087] In this invention, the blanching process imparts a tea aroma to the shaped fuel, while simultaneously improving the basic quality of the raw materials, resulting in better calorific value and burnout temperature. Furthermore, the mixing of heavy materials with tea charcoal to prepare charcoal powder further enhances the calorific value of the shaped fuel, lowers the ignition point and combustion rate, making it easier to ignite and extending its burning time, thus highlighting the efficient utilization of tea tree waste.

[0088] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0089] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a tea-aroma charcoal briquettes with high fuel properties, characterized in that, Prepare according to the following steps: Step 1: Separate the old leaves and branches from the pruned tea tree branches, and perform fixation at 175-180℃. Then, lower the temperature to 135-140℃ and introduce steam for a second fixation process. During fixation, condense the exhaust gas to collect the tea aroma solution. Step 2: The old leaves and branches after the second fixation in Step 1 are gasified to obtain tea charcoal and tea tar. The tea tar is separated by vacuum distillation to obtain a light phenol solution and a heavy substance solution. The heavy substance solution is dried to obtain a heavy substance solid, which is then mixed with tea charcoal to obtain charcoal powder. Step 3: Using sodium hydroxide solution as a solvent, add light phenol solution, polyvinyl acetal, and starch to undergo condensation and gelatinization reactions to obtain an adhesive; Step 4: Mix the charcoal powder, adhesive, tea flavoring solution and water, and cold press to obtain shaped fuel; In step 1, when blanching, the blanching speed for old leaves is 1kg / 15-17min, and the blanching speed for branches is 1kg / 25-28min. When processing tea leaves for the second time, the processing speed for older leaves is 1kg / 5-7min, and the processing speed for branches and stems is 1kg / 10-13min. In step 2, the gasification temperature is 600-700℃ and the gasification time is 30-40 min, wherein the mass ratio of old leaves to branches is 1:1.5-2. The drying temperature for heavy substance solutions is 80-85℃; The tea charcoal is pulverized to 0.075-0.15mm and mixed with heavy solid materials. The mass ratio of tea charcoal to heavy solid materials is 1:0.5-0.

9. In step 3, the mass ratio of the light phenolic solution, polyvinyl acetal, sodium hydroxide, and starch is 1:0.88-0.93:0.2-0.4:0.27-0.35; the sodium hydroxide solution is a 35% sodium hydroxide solution by mass. Polyvinyl methyl acetal includes polyvinyl methyl acetal I and polyvinyl methyl acetal II, with polyvinyl methyl acetal I accounting for 85% of the total mass of polyvinyl methyl acetal and polyvinyl methyl acetal II accounting for 15% of the total mass of polyvinyl methyl acetal. The adhesive synthesis steps in step 3 are as follows: Sodium hydroxide is mixed with water to obtain a 35% sodium hydroxide solution, which is then set aside. Add a light phenol solution to a sodium hydroxide solution and stir until homogeneous at 40-43°C. Then add polyvinyl methyl aldehyde I within 30 minutes. Raise the temperature to 88-90°C, then raise it to 95-97°C within 20 minutes and hold for 15-17 minutes. Cool the temperature to 85-87°C and add polyvinyl methyl aldehyde II. Raise the temperature to 95-97°C and hold for 10-13 minutes. Then cool the temperature to 55-58°C, add starch, and gelatinize for 15-18 minutes. Finally, cool to room temperature to obtain the adhesive.

2. The method for preparing a tea-aroma briquetted fuel with high fuel properties according to claim 1, characterized in that, In step 4, the mass ratio of charcoal powder, adhesive, tea flavoring solution, and water is 1:0.12-0.15:0.15-0.2:0.

2.

3. The method for preparing a tea-aroma charcoal briquettes with high fuel properties according to claim 1, characterized in that, The vacuum distillation temperature is 170-180℃, and the time is 1kg / 10-15min.

4. The method for preparing a tea-aroma briquetted fuel with high fuel properties according to claim 1, characterized in that, The synthesis steps of molded fuel are as follows: mixing adhesive with water to obtain an adhesive solution; Charcoal powder is loaded into a tubular mixer, adhesive aqueous solution and tea aroma solution are loaded into a spray gun, and then loaded into a prototype mold for cold pressing at 20-25 MPa. It is then dried and cured at 105-107℃ to obtain shaped fuel.

5. A tea charcoal briquettes with high fuel properties and a tea aroma prepared by the preparation method according to any one of claims 1-3.

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