A charcoal dry distillation method

Abstract

The present application belongs to the technical field of charcoal dry distillation, and particularly relates to a charcoal dry distillation method. The charcoal dry distillation method provided by the present application is performed by using a charcoal dry distillation device. Wood is filled in a dry distillation tank, and the dry distillation tank filled with the wood is sent into a heating cavity. A combustion machine is used to deliver wood gas and air into a combustion chamber. The wood gas and air are combusted in the combustion chamber to heat the dry distillation tank filled with the wood. When the temperature of the dry distillation tank reaches 180-190 DEG C, the wood starts to crack, and the generated flue gas enters a condensation tower for condensation and diversion. The obtained wood gas is delivered into a gas storage tank, and the obtained wood vinegar is delivered into a liquid collecting pool. When the temperature of the dry distillation tank reaches 480-490 DEG C, the combustion heating is stopped, and the charcoal is obtained in the dry distillation tank. The method provided by the present application has a high resource comprehensive utilization rate. Meanwhile, the method is stable in operation, safe and efficient, and has no waste water, waste gas and waste discharge, so that the ideal target of economic benefit and environmental friendliness is achieved.

Description

Technical Field

[0001] This invention belongs to the field of charcoal dry distillation technology, and specifically relates to a charcoal dry distillation method. Background Technology

[0002] Charcoal dry distillation refers to the process of heating wood at high temperatures (usually above 400°C) in the absence of air, causing the organic matter in the wood, such as cellulose and lignin, to undergo thermal decomposition, releasing gaseous and liquid products, and ultimately obtaining charcoal. Charcoal is an important industrial raw material and domestic fuel, with wide applications in metallurgy, chemical industry, and catering.

[0003] Currently, the main methods for producing charcoal include earthen kiln carbonization, spontaneous combustion, and dry distillation. While earthen kiln carbonization can guarantee charcoal quality, it has a long carbonization time and low production efficiency, generally requiring about 40 days. It also produces a large amount of smoke, with harmful gases in the exhaust being directly released into the atmosphere, severely polluting the environment and failing to meet environmental protection requirements. Spontaneous combustion relies on the material itself to generate heat for carbonization, essentially an oxygen-deficient combustion process. Its disadvantages include dead zones during carbonization and a low yield. Dry distillation, compared to the above methods, has advantages such as shorter carbonization time, simpler operation, and guaranteed product quality, making it a carbonization technology with greater potential for widespread application. However, existing dry distillation carbonization kilns still suffer from problems such as long carbonization and cooling times, lower production efficiency, and large smoke emissions. Summary of the Invention

[0004] The purpose of this invention is to provide a method for carbonizing charcoal. The method provided by this invention produces high-quality charcoal and can effectively collect high-value-added liquid byproducts such as wood vinegar and wood tar, resulting in high resource utilization. At the same time, it is stable, safe, and efficient in operation, with no wastewater, waste gas, or waste emissions, thus achieving the ideal goal of economic benefits and environmental friendliness.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for charcoal dry distillation, using charcoal dry distillation equipment. The charcoal dry distillation equipment includes a dry distillation kiln, a dry distillation tank, a condenser tower, a liquid collection tank, a gas storage tank, and a burner. The burner has a gas supply system and an air supply system. The dry distillation kiln has a combustion chamber and a heating chamber. At least a portion of the dry distillation tank is located within the heating chamber. The condenser tower is connected to the dry distillation tank via a first guide pipe. The gas storage tank is connected to the gas outlet of the condenser tower via a second guide pipe. The liquid collection tank is connected to the liquid outlet of the condenser tower via a third guide pipe. The gas supply system of the burner is connected to the gas storage tank via a fourth guide pipe. The charcoal dry distillation method includes the following steps: Wood is filled into a dry distillation tank, which is then placed into a heating chamber. Wood gas is pre-stored in a gas storage tank and supplied to a burner via a gas supply system. The burner then supplies wood gas and air to the combustion chamber, where they combust and heat the wood-filled dry distillation tank. When the dry distillation tank reaches 180-190°C, the wood begins to decompose. The resulting flue gas enters a condenser tower for condensation and diversion. The resulting wood gas is then transferred to the gas storage tank, and the resulting wood vinegar is transferred to a collection tank. Combustion heating is stopped when the dry distillation tank reaches 480-490°C, resulting in charcoal. The heating rate of the dry distillation tank is 50-70°C / h.

[0006] Preferably, the charcoal dry distillation equipment further includes a flue gas exchanger, which is installed on the first guide pipe, and the flue gas discharge port on the dry distillation tank is connected to the condenser tower through the flue gas exchanger.

[0007] Preferably, the moisture content of the wood is ≤20%.

[0008] Preferably, the moisture content of the wood is 15-18%.

[0009] Preferably, the gas supply rate of the wood gas delivered by the burner is 40-49 m³. 3 / h; the air supply volume delivered by the burner is 50~55m³ / h. 3 / h.

[0010] Preferably, the charcoal has a fixed carbon content ≥80%, volatile matter ≤8%, ash content ≤4%, higher calorific value ≥30MJ / kg, total sulfur (St.d) ≤0.1%; compressive strength ≥18MPa, and bulk density ≥0.95g / cm³. 3 .

[0011] Preferably, the wood vinegar has a pH value of 3 to 3.5, and the wood vinegar contains wood tar, which accounts for 4 to 4.5% of the total mass of the wood vinegar and wood tar.

[0012] Preferably, the relative density d of the wood vinegar is... 20 The content of phenols is 1.02~1.08, the moisture content is 6~11%, the total phenol content is 20~35%, the ash content is ≤1%, the mechanical impurities are ≤0.2%, the heavy metal Pb content is ≤1mg / kg, the heavy metal As content is ≤0.5mg / kg, and the benzo[a]pyrene content is ≤0.001mg / kg.

[0013] Preferably, the gas supply system and air supply system of the burner are configured independently, and each gas supply system and air supply system includes a set of vortex air pumps and a matching single-phase fan speed controller.

[0014] This invention provides a method for charcoal dry distillation, using charcoal dry distillation equipment. The equipment includes a distillation kiln, a distillation tank, a condenser, a liquid collection tank, a gas storage tank, and a burner. The burner has a gas supply system and an air supply system. The distillation kiln has a combustion chamber and a heating chamber. At least a portion of the distillation tank is located within the heating chamber. The condenser is connected to the distillation tank via a first guide pipe. The gas storage tank is connected to the gas outlet of the condenser via a second guide pipe. The liquid collection tank is connected to the liquid outlet of the condenser via a third guide pipe. The gas supply system of the burner is connected to the gas storage tank via a fourth guide pipe. The charcoal dry distillation method includes the following steps: filling wood with… The wood-filled dry distillation tank is placed in a heating chamber. Wood gas is pre-stored in a gas storage tank and supplied to a burner via a gas supply system. The burner then supplies wood gas and air to the combustion chamber. The wood gas and air combust in the combustion chamber, heating the wood-filled dry distillation tank. When the dry distillation tank reaches 180-190°C, the wood begins to decompose. The generated flue gas enters a condenser for condensation and diversion. The resulting wood gas is then sent to the gas storage tank, and the resulting wood vinegar is sent to a collection tank. Combustion heating is stopped when the dry distillation tank reaches 480-490°C, yielding charcoal. The heating rate of the dry distillation tank is 50-70°C / h. Compared with existing technologies, the charcoal dry distillation method provided by this invention has the following advantages: This invention uses wood gas as fuel for dry distillation heating. The wood gas collected in a gas storage tank is transported to the burner via a gas supply system, achieving the recycling of wood gas. The wood gas produced during dry distillation is separated in a condenser and then reintroduced into the gas storage tank, forming a closed-loop gas supply system. This significantly reduces dependence on fossil fuels and dramatically improves energy efficiency. Simultaneously, the burner is equipped with both a gas supply system and an air supply system, with adjustable gas and air volumes, enabling precise control of combustion intensity and avoiding energy waste caused by overheating.

[0015] This invention, through precise control of the heating rate (50~70℃ / h) and the final distillation temperature (480~490℃), can complete the entire distillation process within 6~9 hours. Compared to the traditional earthen kiln carbonization cycle of dozens of days, production efficiency is significantly improved. Simultaneously, by rationally setting the upper limit of the heating rate, the problem of thermal stress cracking caused by uneven heating of the charcoal due to excessively rapid heating and intense burning is effectively avoided, reducing the generation of charcoal dust and broken charcoal, thereby significantly improving the yield of whole charcoal and avoiding economic losses caused by charcoal dust. Combined with dedicated distillation equipment, the distillation tanks can be quickly hoisted and replaced, forming continuous production operations and further improving production efficiency.

[0016] In this invention, the high-temperature flue gas generated during the dry distillation process is treated by a condenser tower, achieving efficient separation of wood gas, wood vinegar, and wood tar. The wood gas is recycled into a storage tank for use as fuel, while the wood vinegar and wood tar are collected in a collection tank. Based on 1800-1900 kg of dry wood per tank, 1150-1180 catties of high-quality charcoal can be produced, along with approximately 2450 catties of wood vinegar and wood tar, resulting in a considerable amount of byproducts. After sedimentation and separation, the wood vinegar and wood tar can be used as agricultural and industrial raw materials, significantly increasing the economic added value of the products.

[0017] This invention achieves clean production throughout the entire charcoal dry distillation process. The recycling of wood gas avoids air pollution caused by direct emissions of combustible gases; condensation treatment effectively recovers wood vinegar and wood tar from the flue gas, solving the environmental problems caused by the indiscriminate emission of flue gas in traditional processes; the entire dry distillation process produces no wastewater, waste gas, or solid waste emissions, meeting the requirements of current green manufacturing and sustainable development. The charcoal dry distillation method provided by this invention is stable, safe, and efficient, achieving a balance between economic benefits and environmental friendliness.

[0018] This invention, through the adjustment functions of the burner's gas and air supply, combined with temperature monitoring, can precisely control the heating rate and final temperature of the dry distillation tank, ensuring the stability of charcoal quality. Compared to traditional heating methods that rely on experience-based judgment, this invention offers higher temperature control accuracy, better product consistency, reduced operational difficulty and reliance on human experience, and facilitates industrial-scale promotion.

[0019] Furthermore, the present invention controls the moisture content of the wood to be 15-18%. This moisture content range ensures that the dry distillation process is completed within a reasonable time, avoiding excessive heat loss due to excessive moisture evaporation and thus prolonging the dry distillation time. It also effectively prevents incomplete carbonization of the charcoal obtained from dry distillation, such as yellow core or incomplete burning, due to excessively low or high moisture content. This ensures that the charcoal is fully carbonized both inside and out, guaranteeing the consistency of product quality. Attached Figure Description

[0020] Figure 1 The charcoal dry distillation equipment provided by the present invention; In the diagram: 100-charcoal dry distillation equipment, 1-drying kiln, 2-drying tank, 3-condensing tower, 4-first guide pipe, 5-gas storage tank, 6-liquid collection tank, 7-burner, 8-thermometer, 9-combustion chamber, 10-second guide pipe, 11-third guide pipe. Detailed Implementation

[0021] This invention provides a method for charcoal dry distillation, using charcoal dry distillation equipment. The charcoal dry distillation equipment includes a dry distillation kiln 1, a dry distillation tank 2, a condenser tower 3, a liquid collection tank 6, a gas storage tank 5, and a burner 7. The burner 7 has a gas supply system and an air supply system. The dry distillation kiln 1 has a combustion chamber 9 and a heating chamber. At least a portion of the dry distillation tank 2 is located in the heating chamber. The condenser tower 3 is connected to the dry distillation tank 2 through a first guide pipe 4. The gas storage tank 5 is connected to the gas outlet of the condenser tower 3 through a second guide pipe 10. The liquid collection tank 6 is connected to the liquid outlet of the condenser tower 3 through a third guide pipe 11. The gas supply system of the burner 7 is connected to the gas storage tank 5 through a fourth guide pipe. The charcoal dry distillation method includes the following steps: Wood is filled into a dry distillation tank 2, which is then placed into a heating chamber. Wood gas is pre-stored in a gas storage tank 5. The wood gas is supplied to a burner 7 via a gas supply system. The burner 7 then supplies wood gas and air to a combustion chamber 9. The wood gas and air burn and heat the wood-filled dry distillation tank 2 in the combustion chamber 9. When the dry distillation tank 2 reaches a temperature of 180-190°C, the wood begins to decompose. The generated flue gas enters a condenser tower 3 for condensation and diversion. The resulting wood gas is then transported to the gas storage tank 5, and the resulting wood vinegar is transported to a collection tank 6. When the dry distillation tank 2 reaches a temperature of 480-490°C, combustion heating is stopped, and charcoal is obtained in the dry distillation tank 2. The heating rate of the dry distillation tank 2 is 50-70°C / h.

[0022] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0023] In this invention, the distillation tank 2 is preferably equipped with a top cover. A thermometer 8 is preferably installed on the distillation tank 2. The charcoal distillation equipment preferably further includes a flue gas exchanger, which is installed on the first guide pipe 4, and the flue gas outlet on the distillation tank 2 is connected to the condenser tower through the flue gas exchanger.

[0024] In this invention, the moisture content of the wood is preferably ≤20%, more preferably 15~18%, and in the embodiment it can be 17%. Preferably, the wood is evenly placed in the dry distillation tank 2. Preferably, the dry distillation tank 2 filled with wood is hoisted into the heating chamber of the dry distillation kiln 1, then the top cover of the dry distillation tank is installed, and the flue gas exhaust port of the dry distillation tank 2 is connected to the flue gas exchanger.

[0025] In this invention, the gas supply system and air supply system of the burner 7 are configured independently. The gas supply system of the burner 7 includes a set of vortex air pumps (HG series manufactured by Sensen Group Co., Ltd.) and a matching single-phase fan speed controller. The vortex air pumps are powered by 220V, have a power of 750W, and a maximum air volume of 75m³ / h. 3 The maximum air pressure is 14.7 kPa. The gas supply system delivers wood gas from gas storage tank 5 to burner 7.

[0026] In this invention, the air supply system of the burner 7 includes a set of vortex air pumps (HG series manufactured by Sensen Group Co., Ltd.) and a matching single-phase fan speed controller. The vortex air pumps are powered by 220V, have a power of 750W, and a maximum air volume of 75m³ / h. 3 / h, with a maximum air pressure of 14.7kPa. The air supply system delivers air to the burner 7.

[0027] In this invention, wood gas and air are mixed and burned in combustion chamber 9. This invention achieves independent and precise control of the gas and air supply volumes by using single-phase fan speed controllers for the gas and air supply systems respectively, thereby regulating the combustion intensity and the heating rate of the dry distillation tank 2.

[0028] In this invention, the heating rate of the dry distillation tank 2 is 50~70℃ / h, preferably 55~65℃ / h, and in the embodiment it can be 60℃ / h. In this invention, the wood preferably begins to decompose when the dry distillation tank 2 is heated to 180℃, and the combustion heating is preferably stopped when the dry distillation tank 2 is heated to 485℃.

[0029] In this invention, the vortex gas pump of the gas supply system of the burner 7 is preferably adjusted to a speed of 1700~1800 r / min by a single-phase fan speed regulator. The gas supply volume of wood gas delivered by the burner 7 is preferably 40~49 m³ / min. 3 / h, which can be 48m in the example. 3 / h. The vortex air pump of the air supply system of the burner 7 has its speed adjusted by a single-phase fan speed controller, preferably to 1900~2000 r / min. The air supply volume delivered by the burner 7 is preferably 50~55 m³ / h. 3 / h, which can be 52m in the example. 3 / h.

[0030] In this invention, the charcoal has a fixed carbon content ≥80%, volatile matter ≤8%, ash content ≤4%, higher calorific value ≥30MJ / kg, and total sulfur (St.d) ≤0.1%. It also has a compressive strength ≥18MPa and a bulk density ≥0.95g / cm³. 3 .

[0031] In this invention, the pH value of the wood vinegar is 3 to 3.5, and the wood vinegar contains wood tar, which accounts for 4 to 4.5% of the total mass of the wood vinegar and wood tar.

[0032] In this invention, the relative density d of the wood vinegar is... 20 The content of phenols is 1.02~1.08, the moisture content is 6~11%, the total phenol content is 20~35%, the ash content is ≤1%, the mechanical impurities are ≤0.2%, the heavy metal Pb content is ≤1mg / kg, the heavy metal As content is ≤0.5mg / kg, and the benzo[a]pyrene content is ≤0.001mg / kg.

[0033] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0034] Example 1 This embodiment provides a method for charcoal dry distillation, including the following steps: 1. Canning The wood (moisture content 17%) is evenly placed in the dry distillation tank, each weighing between 1800 and 1900 kg.

[0035] 2. Loading the kiln The wood-filled distillation tank is hoisted into the heating chamber of the distillation kiln, and the tank cover is installed. The flue gas exhaust port on the distillation tank is then connected to the flue gas exchanger.

[0036] 3. Dry distillation process Air and wood gas (pre-stored in a gas tank for recycling) are introduced into the combustion chamber of the dry distillation kiln through the burner's air supply and gas supply systems. Ignition is then performed. The burner's air supply system consists of a set of vortex air pumps (HG series manufactured by Sensen Group Co., Ltd.) and a matching single-phase fan speed controller. The vortex air pumps in the burner's air supply system have their speed adjusted to 1900 r / min via the single-phase fan speed controller. The air supply volume delivered by the burner is 52 m³ / min. 3 / h. The burner's gas supply system consists of a set of vortex gas pumps (HG series manufactured by Sensen Group Co., Ltd.) and a matching single-phase fan speed controller. The vortex gas pumps in the burner's gas supply system have their speed adjusted to 1800 r / min via the single-phase fan speed controller. The burner supplies 48 m³ / h of wood gas. 3 / h.

[0037] In this embodiment, the heating rate of the dry distillation tank is 60℃ / h by controlling the gas supply and air supply of the burner. When the temperature of the wood in the dry distillation tank rises to 180℃, the wood begins to decompose. The high-temperature flue gas enters the condenser tower through the flue gas exchanger. In the condenser tower, the high-temperature flue gas is condensed and diverted. The resulting wood gas is sent to the gas storage tank, and the resulting wood vinegar (containing wood tar) is sent to the collection tank. When the dry distillation tank continues to heat up to 485℃, combustion heating is stopped, and the charcoal dry distillation is completed, yielding charcoal in the dry distillation tank.

[0038] In this embodiment, 1800-1900 kg of wood can be dry-distilled to produce 1150-1180 catties of high-quality charcoal. The charcoal prepared in this embodiment has a fixed carbon content ≥80%, volatile matter ≤8%, ash content ≤4%, higher calorific value ≥30 MJ / kg, and total sulfur (St.d) ≤0.1%. Its compressive strength ≥18 MPa and bulk density ≥0.95 g / cm³ are also specified. 3 Simultaneously, it produces 2450 catties of wood vinegar and wood tar (2350 catties of wood vinegar and 100 catties of wood tar). After more than 6 months of sedimentation, the wood vinegar and wood tar automatically separate into high-quality raw materials suitable for agricultural and industrial use. The pH value of the wood vinegar and wood tar is 3.35, and the relative density d of the wood vinegar and wood tar is... 20 The content of phenols is 1.02~1.08, the moisture content is 6~11%, the total phenol content is 20~35%, the ash content is ≤1%, the mechanical impurities are ≤0.2%, the heavy metal Pb content is ≤1mg / kg, the heavy metal As content is ≤0.5mg / kg, and the benzo[a]pyrene content is ≤0.001mg / kg.

[0039] The charcoal dry distillation method provided in this embodiment is stable, safe, and efficient, with no wastewater, waste gas, or waste emissions, achieving the ideal goal of economic benefits and environmental friendliness.

[0040] Comparative Example 1 This comparative example provides a charcoal dry distillation method, which is basically the same as the preparation method in Example 1, except that the heating rate of the dry distillation tank is 90℃ / h.

[0041] In Comparative Example 1, the heating rate of the dry distillation tank 2 was greater than 70℃ / h, and the performance indicators of the charcoal obtained were significantly lower than those of Example 1. Specifically, the charcoal product obtained in Comparative Example 1 showed severe cracking, smaller particle size, and increased dust. In Example 1 of this invention, the heating rate of the dry distillation tank 2 was controlled at 60℃ / h, yielding 1150-1180 catties of charcoal per tank. When the heating rate of the dry distillation tank 2 was 90℃ / h, the yield decreased to the current 1100-1120 catties, with an increase of 50-60 catties of charcoal dust.

[0042] Meanwhile, the charcoal prepared in Comparative Example 1 had a lower density, was more brittle when struck, and had a shorter burning time. The charcoal prepared in Example 1 had a high density and hard texture, and each pound of charcoal could burn at high temperature for 2 hours. However, the charcoal prepared in Comparative Example 1 had a lower density due to its excessively fast carbonization rate and increased breakage rate. As a result, the burning time of the charcoal was significantly shortened, with each pound of charcoal burning at high temperature for only 1.5 hours.

[0043] As can be seen from the above, the preparation method provided by the present invention can produce high-quality charcoal by precisely controlling the temperature and time during the high-temperature and oxygen-deficient combustion of wood, which can turn a large amount of waste wood raw materials in rural areas into treasures and achieve a win-win situation for economic and social benefits.

[0044] As can be seen from the above embodiments, the high-temperature flue gas generated during the dry distillation process provided by the present invention, after being treated by a condenser tower, achieves efficient separation of wood gas, wood vinegar, and wood tar. The wood gas is recycled into a gas storage tank for use as fuel, while the wood vinegar and wood tar are collected in a collection tank. Based on 1800-1900 kg of dry wood per tank, 1150-1180 catties of high-quality charcoal can be produced, along with approximately 2450 catties of wood vinegar and wood tar, resulting in a considerable amount of by-products. After sedimentation and separation, the wood vinegar and wood tar can be used as agricultural and industrial raw materials, significantly increasing the economic added value of the products.

[0045] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for the dry distillation of charcoal, characterized in that, The process employs a charcoal dry distillation device, which includes a dry distillation kiln, a dry distillation tank, a condenser tower, a liquid collection tank, a gas storage tank, and a burner. The burner has a gas supply system and an air supply system. The dry distillation kiln has a combustion chamber and a heating chamber. At least a portion of the dry distillation tank is located within the heating chamber. The condenser tower is connected to the dry distillation tank via a first guide pipe. The gas storage tank is connected to the gas outlet of the condenser tower via a second guide pipe. The liquid collection tank is connected to the liquid outlet of the condenser tower via a third guide pipe. The gas supply system of the burner is connected to the gas storage tank via a fourth guide pipe. The charcoal dry distillation method includes the following steps: Wood is filled into a dry distillation tank, which is then placed into a heating chamber. Wood gas is pre-stored in a gas storage tank and supplied to a burner via a gas supply system. The burner then supplies wood gas and air to the combustion chamber, where they combust and heat the wood-filled dry distillation tank. When the dry distillation tank reaches 180-190°C, the wood begins to decompose. The resulting flue gas enters a condenser tower for condensation and diversion. The resulting wood gas is then transferred to the gas storage tank, and the resulting wood vinegar is transferred to a collection tank. Combustion heating is stopped when the dry distillation tank reaches 480-490°C, resulting in charcoal. The heating rate of the dry distillation tank is 50-70°C / h.

2. The charcoal dry distillation method according to claim 1, characterized in that, The charcoal dry distillation equipment also includes a flue gas exchanger, which is installed on the first guide pipe, and the flue gas discharge port on the dry distillation tank is connected to the condenser tower through the flue gas exchanger.

3. The charcoal dry distillation method according to claim 1, characterized in that, The moisture content of the wood is ≤20%.

4. The charcoal dry distillation method according to claim 3, characterized in that, The moisture content of the wood is 15-18%.

5. The charcoal dry distillation method according to claim 1 or 3, characterized in that, The burner supplies 40-49 m³ of wood gas. 3 / h; the air supply volume delivered by the burner is 50~55m³ / h. 3 / h.

6. The charcoal dry distillation method according to claim 1, characterized in that, The charcoal has a fixed carbon content ≥80%, volatile matter ≤8%, ash content ≤4%, higher calorific value ≥30MJ / kg, total sulfur (St.d) ≤0.1%; compressive strength ≥18MPa, and bulk density ≥0.95g / cm³. 3 .

7. The charcoal dry distillation method according to claim 1, characterized in that, The wood vinegar has a pH value of 3 to 3.5 and contains wood tar, which accounts for 4 to 4.5% of the total mass of the wood vinegar and wood tar.

8. The charcoal dry distillation method according to claim 1 or 7, characterized in that, The relative density d of the wood vinegar 20 The content of phenols is 1.02~1.08, the moisture content is 6~11%, the total phenol content is 20~35%, the ash content is ≤1%, the mechanical impurities are ≤0.2%, the heavy metal Pb content is ≤1mg / kg, the heavy metal As content is ≤0.5mg / kg, and the benzo[a]pyrene content is ≤0.001mg / kg.

9. The charcoal dry distillation method according to claim 1, characterized in that, The gas supply system and air supply system of the burner are configured independently. Both the gas supply system and the air supply system include a set of vortex air pumps and a matching single-phase fan speed controller.

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