A method for rapid detoxification of biochar

Abstract

The present application relates to a kind of biological charcoal rapid detoxification preparation methods, comprising the following steps: S1: the preparation of biological charcoal: the pyrolysis of good biological charcoal is broken and is classified to target particle size range;S2: the extraction of biological charcoal: using volatile organic acid solution in extraction device to the biological charcoal of S1 acquisition is extracted treatment;S3: the acquisition of detoxification biological charcoal: after the biological charcoal of S2 obtains is dried, obtain detoxification biological charcoal.Compared with prior art, the present application can greatly reduce the water consumption of biological charcoal detoxification treatment, and more toxic and harmful substances on the surface of biological charcoal can be removed, without secondary environmental pollution;The equipment involved in the present application is simple, easy to operate, and the corresponding scale of extraction equipment can be used according to demand;Provide a large quantity, low cost, environmentally friendly biological charcoal detoxification solution.

Description

Technical Field

[0001] This invention relates to the field of environmental engineering materials technology, and in particular to a method for rapid detoxification preparation of biochar. Background Technology

[0002] Due to its porous structure, pH buffering capacity, and electrical conductivity, biochar can effectively solve problems such as low methane yield, long start-up period, and process instability when added to anaerobic digestion processes. In composting, it can accelerate the degradation of organic matter and the formation of humus. It can also be used as a soil conditioner to promote plant growth and carbon sequestration. However, during the pyrolysis preparation of biochar, factors such as the type of raw materials, pyrolysis temperature, pyrolysis atmosphere, and pyrolysis time can affect the preparation of biochar, leading to the generation of toxic and harmful substances that remain on the surface of the biochar. These toxic and harmful substances not only pose risks to the environment and human health during biochar application but also have a toxic effect on the functional microorganisms involved in the biochar reaction, affecting the efficiency of biochar application and even inhibiting its effectiveness.

[0003] To address the issue of toxic and harmful substances on the surface of biochar, physical or chemical treatments are used to reduce these substances, thereby improving the safety and functional stability of biochar during application and enabling it to fulfill its intended functions. Currently, the main methods for biochar detoxification are water washing and chemical washing (e.g., Chinese invention patents with publication numbers CN107970751A and CN107970751A). Water washing is simple, requiring only soaking the biochar in water and gently stirring, but it consumes a large amount of water, is time-consuming, has a low throughput, and can only remove a limited number of toxic and harmful substances. Chemical washing generally involves washing biochar with an acidic solution, which can remove more toxic and harmful substances than water washing, but it also consumes a large amount of water, and the chemical agents require additional treatment after washing. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a rapid detoxification method for biochar. This method is simple and significantly reduces water consumption compared to traditional water washing and chemical washing methods. It effectively and quickly removes toxic and harmful substances from the surface of biochar, reducing environmental and human health risks during biochar application and making it more suitable as an environmentally compatible and friendly material. This invention greatly reduces water consumption in biochar detoxification treatment and removes more toxic and harmful substances from the surface of biochar without causing secondary environmental pollution. The equipment involved in this invention is simple and easy to operate, and appropriate scale of extraction equipment can be used according to needs. It provides a large-scale, low-cost, and environmentally friendly biochar detoxification solution.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] This invention utilizes volatile organic acids to perform steam extraction on raw biochar. The high-temperature volatile organic acid solution vapor permeates to the surface of the biochar, causing the toxic and harmful substances on the surface of the biochar to desorb and volatilize, thereby obtaining detoxified biochar.

[0007] This invention provides a method for rapid detoxification preparation of biochar, comprising the following steps:

[0008] S1: Preparation of biochar: Crush and sieve the pyrolyzed biochar to the target particle size range.

[0009] S2: Extraction of biochar: The biochar obtained in S1 is extracted using a volatile organic acid solution in an extraction device; preferably, a volatile organic acid solution with a concentration of 0.1-0.3 mol / L is used, and the biochar is extracted for 20-40 minutes at a temperature of 100-120°C and atmospheric pressure; preferably, the extraction device in S2 includes: a biochar treatment platform, a volatile organic acid solution heating component, and a steam condensation reflux component, with the volatile organic acid solution heating component located below the biochar treatment platform; the steam condensation reflux component returns the condensed volatile organic acid solution to the volatile organic acid solution heating component, ensuring that no additional volatile organic acid solution needs to be added during the extraction process to prevent burning dry, thus improving the utilization rate of the volatile organic acid solution.

[0010] S3: Obtaining Detoxified Biochar: The biochar obtained in S2 is dried to obtain detoxified biochar. Preferably, the treated biochar is dried at 105 degrees Celsius to constant weight to obtain dried detoxified biochar. If it is subsequently used in high-moisture-content applications such as anaerobic digestion, drying is not required. The detoxified biochar after steam extraction can be used directly or dried and stored, depending on the subsequent application scenario.

[0011] Furthermore, the biochar processing platform is made of stainless steel mesh or nylon mesh.

[0012] Furthermore, the heat energy generated by the steam condensation reflux assembly can be recovered and utilized.

[0013] Furthermore, the volatile organic acid solution is one or more of acetic acid, propionic acid, and butyric acid.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] (1) This invention utilizes the flowing steam of a volatile organic acid solution to promote the desorption and volatilization of toxic and harmful substances on the surface of biochar. Simultaneously, some toxic and harmful substances on the biochar surface may be converted into volatile substances in an acidic environment, detaching from the biochar surface with the steam. Therefore, using a volatile organic acid solution for steam extraction of biochar can effectively remove toxic and harmful substances from its surface, achieving detoxification treatment of the biochar. Furthermore, compared to traditional water washing and steam extraction, and even compared to washing with high-leaching-rate chemical agents such as methanol, it can remove more toxic and harmful substances from the biochar surface, improving the environmental friendliness and safety of the biochar.

[0016] (2) Based on the total organic carbon leached from the detoxified biochar and the main physicochemical parameters of the biochar (leaching pH value, specific surface area, contact angle, etc.), this invention has determined an economically reasonable range of volatile organic acid concentrations, operating temperature and pressure of the distillation equipment, and distillation time.

[0017] (3) The inventors have previously demonstrated that after extracting biochar from acidic anaerobic digestion culture medium, the extract has a certain inhibitory effect on the functional microorganisms in the anaerobic digestion process. This invention uses a volatile organic acid solution to perform distillation and detoxification treatment on the biochar, obtaining biochar with fewer toxic and harmful substances under acidic conditions, making it more suitable as an environmentally compatible and friendly material. Furthermore, volatile organic acids are useful carbon sources for microorganisms in both anaerobic and aerobic environments and are easily further biodegraded; therefore, the volatile organic acids remaining on the surface of the char material are also very environmentally friendly.

[0018] (4) The equipment used in this invention is simple and easy to operate. Conventional industrial distillers, strippers and other equipment can be easily adjusted and are suitable for the rapid detoxification preparation of biochar proposed in this invention.

[0019] (5) This invention utilizes volatile organic acid vapor to detoxify biochar, overcoming the disadvantages of traditional water washing and chemical washing methods, which involve large water consumption, large amount of chemicals, and long processing time. It provides a large-scale, low-cost, and environmentally friendly biochar detoxification solution. Attached Figure Description

[0020] Figure 1 A flowchart of a method for rapid detoxification preparation of biochar.

[0021] Figure 2 This is a schematic diagram of the distillation apparatus. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0023] Example 1

[0024] This embodiment provides a method for rapid detoxification preparation of biochar, such as... Figure 1 As shown, it includes the following steps:

[0025] S1: Preparation of biochar: After air-drying the pine wood, cut it into pieces about 10cm long and put it into the carbonization furnace. The heating rate during the pyrolysis process is 8.5℃ / min, the target temperature is 500℃, and it is maintained for 15h. After the pyrolysis process is completed, let the biochar cool naturally to room temperature and take it out for use. Then crush and sieve the biochar, and take the biochar with a size of 0.25-2mm for use.

[0026] S2: Extraction of biochar: such as Figure 2 As shown, 100g of sieved biochar was placed in a biochar processing platform (15L volume), which was a mesh tray covered with 200-mesh nylon mesh. A 0.2mol / L acetic acid aqueous solution was used to extract the biochar for 30 minutes at 110℃ and normal pressure. The condensed volatile organic acid solution was then returned to the volatile organic acid solution heating assembly, which included a heater, a controller, and a heating container. The heater provided heat, and the controller monitored and regulated the heating process. The steam condensation and reflux assembly included a condenser, a cooling water unit, and a reflux pipe. After steam was generated during the heating process, it was cooled into liquid by the condenser and then returned to the heating assembly through the reflux pipe. The cooling water unit provided the cooling medium to aid in the condensation of the steam.

[0027] S3: Obtaining detoxified biochar: The treated biochar is dried at 105 degrees Celsius to constant weight to obtain dried detoxified biochar.

[0028] Ultrapure water leaching experiments were conducted on raw biochar, biochar treated with steam extraction (control group), and biochar treated with acetic acid aqueous solution extraction (experimental group). The dissolved organic carbon (DOC) in the leachate was tested, and the results are shown in Table 1.

[0029] Table 1

[0030]

[0031] It is evident that, compared to steam extraction, the amount of organic matter that can be removed from biochar treated with acetic acid aqueous solution is increased from 0.13 mg-C / g-biochar to 2.63 mg-C / g-biochar. Evaporation treatment with volatile organic acids can desorb more toxic and harmful substances onto the surface of biochar, which can then be removed by soaking in a small amount of water.

[0032] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0033] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for rapid detoxification preparation of biochar, characterized in that, Includes the following steps: S1: Preparation of biochar: Crush and sieve the pyrolyzed biochar to the target particle size range. S2: Extraction of biochar: The biochar obtained in S1 is extracted using a volatile organic acid solution in an extraction device. The extraction device includes a biochar processing platform, a volatile organic acid solution heating component, and a steam condensation reflux component. The volatile organic acid solution heating component is located below the biochar processing platform. The steam condensation reflux component returns the condensed volatile organic acid solution to the volatile organic acid solution heating component. The concentration range of the volatile organic acid solution used in the extraction process is 0.1~0.3 mol / L. The operating temperature of the extraction equipment is 100℃~120℃, and the operating pressure is atmospheric pressure. The volatile organic acid solution is one or more of acetic acid, propionic acid, and butyric acid. S3: Obtaining detoxified biochar: The biochar obtained in S2 is dried to obtain detoxified biochar.

2. The method for rapid detoxification preparation of biochar according to claim 1, characterized in that, The biochar processing platform is a stainless steel screen or a nylon screen.

3. The method for rapid detoxification preparation of biochar according to claim 1, characterized in that, The steam condensation and return assembly includes a condenser, a cooling water unit, and a return pipe. After steam is generated during the heating process, it is cooled into liquid by the condenser and then returns to the heating assembly through the return pipe. The cooling water unit is used to provide a cooling medium to condense the steam.

4. The method for rapid detoxification preparation of biochar according to claim 1, characterized in that, The volatile organic acid solution heating assembly includes a heater, a controller, and a heating container. The heater is used to provide heat, the controller is used to monitor and regulate the heating process, and the heating container is used to hold biochar.

5. The method for rapid detoxification preparation of biochar according to claim 1, characterized in that, The steam condensation and return assembly includes a condenser, a cooling water unit, and a return pipe. After steam is generated during the heating process, it is cooled into liquid by the condenser and then returns to the heating assembly through the return pipe. The cooling water unit is used to provide a cooling medium for condensing the steam.

6. The method for rapid detoxification preparation of biochar according to claim 1, characterized in that, In S2, the time for steam extraction of biochar is 20-40 minutes.

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