Civil biomass charcoal and preparation method thereof

Abstract

The invention relates to civil biomass charcoal and a preparation method thereof, in particular to the technical field of biomass charcoal preparation, and the civil biomass charcoal is prepared by the following steps: by taking biomass as a raw material, firstly performing catalytic conversion to obtain carbide, and then forming the carbide to prepare a carbon rod; and finally, mixing the carbon rod with a tar cracking agent, and carrying out microwave, ultrasonic wave and electric auxiliary heating treatment. Wherein the tar cracking agent is any one of bagasse biochar, reed biochar or coconut shell biochar. The biomass charcoal prepared by the invention is low in volatile component and good in product quality, and can be used as barbecue charcoal. Besides, in the preparation method, the biomass charcoal is prepared by deeply processing the carbide through cooperation of microwave heating, electric auxiliary heating and ultrasonic waves, and the preparation method is different from traditional earth kiln production and fixed bed pyrolysis carbonization technologies, has the advantages of efficient heating, enhancement of reaction efficiency, improvement of product yield and quality, energy conservation, environmental protection and the like, and is relatively good in application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of biochar preparation, and in particular relates to civil biochar and a preparation method thereof. Background Art

[0002] Biochar is a solid material rich in carbon, which is made from carbon-containing materials such as wood chips, straw or bamboo, and is produced by dry distillation and pyrolysis under anaerobic or low-oxygen conditions. At present, the carbonization process of biochar mostly adopts traditional earth kiln production or fixed bed pyrolysis carbonization technology.

[0003] Traditional earth kiln carbonization furnaces have very strict requirements on fire control during the combustion process. Since the kiln body is mostly made of red bricks, it is generally large in volume and mostly uses hard logs for charcoal burning. Not only is there a serious waste of resources, but the production process also has poor labor conditions, high intensity, long production cycle, and serious pollution. It is impossible to pyrolyze and make charcoal from a large number of waste straw, rice straw and other abundant biomass raw materials in rural areas. Fixed bed pyrolysis carbonization technology arranges different numbers of high-temperature heat pipes at different positions and uses the isothermal property of the heat pipes to achieve the purpose of charcoal production. However, due to the generation of a large amount of tar and volatile gas escape, the biochar yield is low, the pipeline is easy to clog, and the process implementation is difficult and difficult to promote. It can be seen that the current biochar preparation process has problems such as low yield, poor charcoal quality, low combustion calorific value, high energy consumption and environmental pollution caused by traditional methods.

[0004] At present, biochar is widely used in the fields of civil fuel, soil improvement, pollution particles and energy storage. Among them, biochar can be used in the form of barbecue charcoal in the field of civil fuel. Compared with other civil fuels, barbecue charcoal has more stringent standards in calorific value, safety, combustion characteristics such as smokeless and odorless, stable and long-lasting combustion, etc. This also puts forward more stringent requirements on the preparation process of biochar. Summary of the invention

[0005] The purpose of the present invention is to provide a civil biomass charcoal and a preparation method thereof in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions: The first aspect of the present invention provides a civilian biomass charcoal, which is made from biomass as raw material, which is first catalytically converted to obtain a carbonized product, which is then formed into a carbon rod, and finally the carbon rod is mixed with a tar cracking agent and subjected to microwave, ultrasonic and electrically assisted heating treatment to obtain the obtained product.

[0007] As a further optimization scheme of the present invention, the biomass is any one of bamboo blocks, wood blocks, corn stalks or cotton stalks.

[0008] As a further optimization scheme of the present invention, the biochar is any one of bamboo chip biochar, wood chip biochar, bagasse biochar, reed biochar, coconut shell biochar or walnut shell biochar.

[0009] The second aspect of the present invention also provides a method for preparing biochar for civil use, comprising the following steps: (1) Catalytically converting biomass into carbonized material; (2) firstly crushing the carbonized product obtained in step (1), then mixing the crushed carbonized product with a binder, a surfactant and water according to a formula, stirring and forming a rod to obtain a carbon rod; (3) Under an inert gas atmosphere, the carbon rod obtained in step (2) is mixed with a tar cracking agent and then subjected to deep processing by three heating methods: microwave, ultrasonic and electric assisted heating. Civilian biochar is then obtained by cooling.

[0010] As a further optimization scheme of the present invention, step (1) is specifically as follows: cutting the biomass into segments and feeding them into a carbonization furnace, heating the temperature in the carbonization furnace to 200-300° C. by steam heating, then adding a catalyst, and carbonizing for 2 h-3 h under an inert gas atmosphere to obtain a carbonized product.

[0011] As a further optimization scheme of the present invention, in step (2), the mass ratio of the carbonized material to the adhesive and the surfactant is 9.2:0.3-1.0:0.1-0.3.

[0012] As a further optimization scheme of the present invention, in step (3), the amount of the tar cracking agent is determined according to the tar content in the carbonized material to be cracked, and the mass ratio of the tar cracking agent to tar is 1:1-3.

[0013] As a further optimization solution of the present invention, the inert gas atmosphere is any one of a nitrogen atmosphere, a helium atmosphere, a neon atmosphere or an argon atmosphere.

[0014] As a further optimization scheme of the present invention, step (3) is specifically as follows: the carbon rod obtained in step (2) is mixed with a tar cracking agent and then fed into a carbonization furnace, and the temperature in the furnace is first raised to 180-200°C by three heating methods, namely, microwave, ultrasonic and electric assisted heating, and then an inert gas is introduced into the carbonization furnace to place the sealed space in the furnace in an oxygen-deficient environment, and heating is continued to raise the temperature in the furnace to 450-500°C, and then the heating is stopped and the temperature is lowered.

[0015] As a further optimization scheme of the present invention, the microwave power is 500W-100KW, the ultrasonic power is 500W-20KW, and the electric auxiliary heating power is 1KW-100KW.

[0016] Therefore, the beneficial effects of the present invention are: The biomass charcoal provided by the present invention is obtained by firstly utilizing biomass catalytic conversion to obtain carbonized product, then molding the carbonized product to obtain carbon rod, and finally mixing the carbon rod with a tar cracking agent and subjecting it to microwave, ultrasonic and electrically assisted heating treatment.

[0017] First, the present invention can achieve the following advantages by adopting the synergistic effect of microwave, ultrasonic and electric-assisted heating: (1) High-efficiency heating and uniformity: The rapidity and selectivity of microwave heating combined with the uniformity of electric-assisted heating can further optimize the temperature field in the furnace and ensure that the material is heated more evenly; (2) Enhanced reaction efficiency: The cavitation effect of ultrasonic waves and the heating effect of microwaves work synergistically to significantly improve the heat and mass transfer efficiency, accelerate the carbonization reaction, and increase the product yield; (3) Improved product quality: Through the dispersion effect of ultrasonic waves and the uniform heating of microwaves, not only can local overheating or overcooling be effectively avoided to ensure the stability of the quality of biochar, but the volatile matter in the biochar can also be effectively reduced to improve the combustion calorific value of the biochar; (4) Energy saving and environmental protection: The high efficiency of microwave heating and the rapid heating ability of electric-assisted heating, combined with the dispersion effect of ultrasonic waves, can reduce energy consumption and reduce production costs.

[0018] Secondly, the present invention can further reduce the volatile matter in the biochar and improve the quality of the biochar by selecting bagasse biochar, reed biochar or coconut shell biochar as tar cracking agents and mixing them with carbon rods for deep processing, so that it can be better applied in the field of civilian fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The civil biomass charcoal prepared from bamboo segments as raw materials provided in the embodiment of the present invention; Figure 2 This is the effect of different deep processing and heating treatment methods provided by the present invention on the quality and performance of civil biomass charcoal. In the figure, A is total moisture; B is fixed carbon; C is ash; D is volatile matter; Figure 3 The effects of different deep processing and heating treatment methods provided by the present invention on the yield of civil biomass charcoal; Figure 4 This is the effect of using different types of tar cracking agents provided by the present invention on the quality performance of civil biomass charcoal. In the figure, A is total moisture; B is fixed carbon; C is ash; and D is volatile matter. DETAILED DESCRIPTION

[0020] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0021] The civilian biomass charcoal disclosed in the present invention uses biomass as raw material, first undergoes catalytic conversion to obtain carbonized product, then shapes the carbonized product to obtain carbon rods, and finally mixes the carbon rods with a tar cracking agent and obtains the obtained product after microwave, ultrasonic and electric-assisted heating treatment.

[0022] In the present invention, the biomass selected is wood blocks or crop straw; the tar cracking agent selected is any one of bamboo biochar, wood chip biochar, bagasse biochar, reed biochar, coconut shell biochar or walnut shell biochar.

[0023] The specific preparation method is: (1) Cutting biomass into segments and catalytically converting the biomass into carbonized product; specifically, cutting the biomass into segments and feeding it into a carbonization furnace, heating the temperature in the carbonization furnace to 200-300°C by steam heating, then adding a catalyst, and carbonizing the biomass for 2h-3h under an inert gas atmosphere to obtain a carbonized product, wherein the inert gas atmosphere is any one of nitrogen atmosphere, helium atmosphere, neon atmosphere or argon atmosphere, and the catalyst is any one of polymaleic acid, hydrochloric acid, sodium hydroxide or potassium hydroxide, but not limited thereto, and the amount of the catalyst is 3% of the mass of the biomass raw material; (2) firstly crushing the carbonized product obtained in step (1) and passing it through a 100-mesh sieve, then mixing the crushed carbonized product with a binder, a surfactant and water in a mass ratio of 9.2:0.3-1.0:0.1-0.3, stirring and forming a rod to obtain a carbon rod; (3) performing deep processing on the carbon rod obtained in step (2); Specifically, the carbon rod obtained in step (2) is mixed with a tar cracking agent and then fed into a carbonization furnace. The temperature in the furnace is first raised to 180-200°C by using three heating methods, namely microwave, ultrasonic and electric assisted heating. Then, an inert gas is introduced into the carbonization furnace to place the sealed space in the furnace in an oxygen-deficient environment. The heating is continued to raise the temperature in the furnace to 450-500°C. The heating is stopped and the temperature is lowered to obtain civilian biochar.

[0024] Furthermore, the dosage of the tar cracking agent is determined according to the tar content to be cracked in the carbonized material, usually the tar cracking agent: tar = 1:1-3.

[0025] Furthermore, the microwave power is 500W-100KW, the ultrasonic power is 500W-20KW, and the electric-assisted heating power is 1KW-100KW. The microwave power, ultrasonic power and electric-assisted heating power are adjusted according to the required temperature rise rate and time in the furnace. The inert gas is any one of nitrogen, helium, neon or argon.

[0026] In the deep processing process, firstly, microwave heating can greatly shorten the carbonization time compared with traditional kiln carbonization. On the other hand, microwave heating has low heat loss and high thermal energy utilization, so that the heated material is heated inside and outside, avoiding the cold center phenomenon caused by traditional heating. Secondly, electric auxiliary heating can directly heat up the furnace body, with high thermal efficiency. The use of electric heating device in the preparation process of biochar can make the temperature in the carbonization furnace quickly reach the set value, shorten the preheating time, and improve production efficiency. Electric heating can also achieve overall uniform heating or local heating according to the actual process requirements of heating. In the carbonization furnace, by reasonably arranging the electric heating elements, the materials in the furnace can be heated more evenly, avoiding inconsistent biochar quality caused by local overheating or overcooling, thereby improving the stability of product quality. Finally, the high-frequency vibration of ultrasound can cause local high temperature and high pressure in the carbon material, destroying the interaction forces such as van der Waals force between particles, so that the particles are more evenly dispersed, which is convenient for more sufficient heating in the subsequent heating process and higher carbonization efficiency.

[0027] The reference standard for the quality evaluation of biochar is the "Charcoal for Barbecue" group standard (T / CNFPIA 3025-2022). The specific evaluation indicators are shown in Table 1.

[0028] Table 1. Evaluation indicators ; The beneficial effects of the present invention are described below through specific embodiments.

[0029] Example 1

[0030] The method for preparing civil biochar provided in this embodiment comprises the following steps: (1) The bamboo segments were crushed into flakes and then fed into a carbonization furnace. The furnace door was closed and the temperature was set to 300 °C. The temperature was raised by steam heating and a catalyst (3% of the mass of the bamboo) was added to increase the reaction rate and reduce the heating time. After carbonization for 2 h under a nitrogen atmosphere, the temperature was lowered and the material was taken out to obtain a carbonized product.

[0031] (2) 10 kg of prepared carbonized material is conveyed to a crusher for crushing and screening into particles below 100 meshes. The crushed carbonized material particles, water, binder, surfactant, etc. are measured and weighed at a mass ratio of 9.2:0.3:0.1. The measured raw and auxiliary materials are poured into a mixer, and the mixer frequency is set for stirring. The stirred materials are put into a rod making machine, and the rod making machine frequency is set to 45 Hz. The propulsion speed of the screw propeller is increased to make the carbon rods more compact after rod making.

[0032] (3) The charcoal sticks obtained in step (2) are mixed with the bamboo biochar and then fed into a carbonization furnace. The amount of bamboo biochar used is determined according to the tar content to be cracked in the carbonized product. The ratio of bamboo biochar to tar is 1:1. The temperature in the furnace is first raised to 180°C by using microwave, ultrasonic and electric assisted heating. Then nitrogen is introduced into the carbonization furnace to make the sealed space in the furnace anoxic environment to eliminate oxygen interference. The heating is continued to raise the temperature in the furnace. The heating time is 1 hour. After the temperature is raised to 450°C and stabilized, the heating is stopped and the temperature is lowered to obtain civil biochar. Figure 1 shown.

[0033] Example 2

[0034] The method for preparing civil biochar provided in this embodiment comprises the following steps: (1) Cut the wood blocks into sections and place them into a carbonization furnace. After closing the furnace door, set the temperature to 200°C, heat it with steam, and add a catalyst (3% of the mass of the wood block) to increase the reaction rate and reduce the heating time. After carbonizing for 3 hours under a nitrogen atmosphere, cool the material and take it out to obtain a carbonized product.

[0035] (2) Take 10 kg of the prepared carbonized material and transport it to the crusher for crushing and screening into particles below 100 mesh. The crushed carbonized particles, water, binder, surfactant, etc. are measured and weighed at a mass ratio of 9.2:1.0:0.3. The measured raw and auxiliary materials are poured into the mixer, and the mixer frequency is set for stirring. The stirred materials are put into the rod making machine, and the rod making machine frequency is set to 45 Hz. The propulsion speed of the screw propeller is increased to make the carbon rod more compact after the rod is formed.

[0036] (3) The charcoal rods and sawdust biochar obtained in step (2) are fed into a carbonization furnace. The amount of sawdust biochar is determined according to the tar content to be cracked in the carbonized product, and the ratio of sawdust biochar to tar is 1:2. The temperature in the furnace is first raised to 200°C by using microwave, ultrasonic and electric assisted heating. Then nitrogen is introduced into the carbonization furnace to make the sealed space in the furnace an oxygen-deficient environment to eliminate oxygen interference. The heating is continued to raise the temperature in the furnace. The heating time is 1 hour. After the temperature is raised to 500°C and stabilized, the heating is stopped and the temperature is lowered to obtain civil biochar.

[0037] Example 3

[0038] The method for preparing civil biochar provided in this embodiment comprises the following steps: (1) Cut corn stalks into segments and put them into a carbonization furnace. After closing the furnace door, set the temperature to 200°C, heat it with steam, and add a catalyst (the amount is 3% of the mass of the corn stalks). After carbonizing for 3 hours under a nitrogen atmosphere, cool it down and take out the material to obtain a carbonized product. (2) Take 10 kg of the prepared carbonized material and transport it to the crusher for crushing and screening into particles below 100 meshes. The crushed carbonized particles, water, binder, surfactant, etc. are measured and weighed at a mass ratio of 9.2:0.6:0.2. The measured raw and auxiliary materials are poured into the mixer, and the mixer frequency is set for stirring. The stirred materials are put into the rod making machine, and the rod making machine frequency is set to 45 Hz. The propulsion speed of the screw propeller is increased to make the carbon rods more compact after rod forming. (3) The charcoal rod obtained in step (2) is mixed with bagasse biochar and then fed into a carbonization furnace. The amount of bagasse biochar used is determined according to the tar content to be cracked in the carbonized material, bagasse biochar: tar = 1:3. The temperature in the furnace is first raised to 190°C by using microwave, ultrasonic and electric assisted heating. Then nitrogen is introduced into the carbonization furnace to make the sealed space in the furnace an oxygen-deficient environment to eliminate oxygen interference. The heating is continued to raise the temperature in the furnace. The heating time is 1 hour. After the temperature is raised to 470°C and stabilized, the heating is stopped and the temperature is lowered to obtain civil biochar.

[0039] Example 4

[0040] The method for preparing civil biochar provided in this embodiment is different from that in Embodiment 1 in that the biomass raw material used is cotton straw and the tar cracking agent used is reed biochar.

[0041] Verification test 1. The influence of different deep processing and heating treatment methods on the quality and performance of civil biochar.

[0042] According to the method for preparing civil biochar disclosed in Example 1, different deep processing and heating treatment methods are adjusted according to Table 2 to prepare biochar.

[0043] Table 2. Different deep processing heating treatment methods ; Note: “+” indicates that the treatment was performed; “-” indicates that the treatment was not performed.

[0044] The biochar prepared from the A-1 to A-7 treatment groups was subjected to industrial analysis in accordance with the group standard "Charcoal for Barbecue" (T / CNFPIA3025-2022). The industrial analysis data of the biochar prepared from the A-1 to A-7 treatment groups are shown in Table 3. Figure 2 shown.

[0045] Table 3. Industrial analysis data statistics ; It can be seen from Table 3 that different deep processing heating treatment methods have an impact on the quality of the prepared biochar. By comparing the A-1 treatment group with the A-3 treatment group, the A-4 treatment group, the A-4 treatment group and the A-5 treatment group, it can be seen that microwave heating treatment and ultrasonic heating treatment have a positive effect on reducing the volatile matter in the biochar. By comparing the A-1 treatment group with the A-2 treatment group, it can be seen that although the electric-assisted heating treatment has no significant effect on reducing the volatile matter content in the biochar, it has a certain positive effect on reducing the total moisture in the biochar.

[0046] In addition, the present invention further counted the yield of biochar in the treatment groups A-1 to A-7. The yield of biochar was calculated by dividing the difference between the mass of biomass and the mass of the final biochar by the mass of biomass. The results are shown in Table 4. Figure 3 shown.

[0047] Table 4. Yield statistics of treatment groups A-1 to A-7 ; As can be seen from Table 4, in the A-1 treatment group, the yield of biochar treated by microwave heating, ultrasonic heating and electric-assisted heating can be increased to more than 55%. The rapidity and selectivity of microwave heating combined with the uniformity of electric-assisted heating can further optimize the temperature field in the furnace and ensure that the material is heated more evenly. The synergistic effect of ultrasonic cavitation effect and microwave heating effect can significantly improve the heat and mass transfer efficiency, accelerate the carbonization reaction, and further improve the yield of biochar.

[0048] 2. The impact of different types of tar cracking agents on the quality and performance of civilian biochar.

[0049] According to the method for preparing civil biochar disclosed in Example 1, the use of different types of tar cracking agents was adjusted according to Table 5.

[0050] Table 5. Use of different types of tar cracking agents ; The biochar prepared from the B-1 to B-8 treatment groups was subjected to industrial analysis in accordance with the group standard for barbecue charcoal (T / CNFPIA3025-2022). The industrial analysis data are shown in Table 6. Figure 4 shown.

[0051] Table 6. Industrial analysis data statistics ; It can be seen from Table 6 that in the process of deep processing of carbonized materials, the selection of different types of biochar has different degrees of influence on reducing the volatile matter in biochar. The selection of reed biochar has the best effect on reducing the volatile matter in the final biochar. The lower the volatile matter, the higher the calorific value of the biochar, and the less harmful gases are produced during combustion, which has a positive significance for improving the quality of biochar and can be better used as barbecue charcoal.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A civil biochar, characterized in that: The civilian biochar is made of biomass as raw material, which is first catalytically converted to obtain a carbonized product, and then the carbonized product is formed into a carbon rod, and finally the carbon rod is mixed with a tar cracking agent and treated with microwave, ultrasonic and electric assisted heating; wherein the tar cracking agent is any one of bagasse biochar, reed biochar or coconut shell biochar.

2. The biochar for civil use according to claim 1, characterized in that: The biomass is any one of bamboo pieces, wood pieces, corn stalks or cotton stalks.

3. A method for preparing civil biochar according to any one of claims 1-2, characterized in that: The preparation method comprises the following steps: (1) Catalytically converting biomass into carbonized material; (2) firstly crushing the carbonized product obtained in step (1), then mixing the crushed carbonized product with a binder, a surfactant and water according to a formula, stirring and forming a rod to obtain a carbon rod; (3) Under an inert gas atmosphere, the carbon rod obtained in step (2) is mixed with a tar cracking agent and then subjected to deep processing by three heating methods: microwave, ultrasonic and electric assisted heating. Civilian biochar is then obtained by cooling.

4. The method for preparing biochar for civil use according to claim 3, characterized in that: Step (1) is specifically as follows: cutting the biomass into segments and feeding them into a carbonization furnace, heating the carbonization furnace to a temperature of 200-300° C. by steam heating, then adding a catalyst, and carbonizing for 2 h-3 h under an inert gas atmosphere to obtain a carbonized product.

5. The method for preparing biochar for civil use according to claim 3, characterized in that: In step (2), the mass ratio of the carbonized material to the adhesive and the surfactant is 9.2:0.3-1.0:0.1-0.

3.

6. The method for preparing biochar for civil use according to claim 3, characterized in that: In step (3), the amount of the tar cracking agent is determined according to the tar content to be cracked in the carbonized material, and the mass ratio of the tar cracking agent to tar is 1:1-3.

7. The method for preparing biochar for civil use according to claim 3, characterized in that: The inert gas atmosphere is any one of a nitrogen atmosphere, a helium atmosphere, a neon atmosphere or an argon atmosphere.

8. The method for preparing biochar for civil use according to claim 3, characterized in that: Step (3) is specifically as follows: the carbon rod obtained in step (2) is mixed with a tar cracking agent and then fed into a carbonization furnace, and the temperature in the furnace is first raised to 180-200°C by using three heating methods, namely microwave, ultrasonic and electric auxiliary heating, and then an inert gas is introduced into the carbonization furnace to make the sealed space in the furnace an oxygen-deficient environment, and the heating is continued to raise the temperature in the furnace to 450-500°C, and then the heating is stopped and the temperature is lowered.

9. The method for preparing biochar for civil use according to claim 3, characterized in that: In step (3), the microwave power is 500W-100KW, the ultrasonic power is 500W-20KW, and the electric auxiliary heating power is 1KW-100KW.

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