Energy-saving process for activating biochar with wood vinegar vapor by thermo-chemical-physical coupling method
By using a thermochemical-physical coupling method to activate biochar with wood vinegar steam, the problems of high energy consumption and chemical pollution in biochar activation have been solved, achieving energy reduction and effective utilization of wood vinegar, thus achieving energy conservation and emission reduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHUZHOU JINCHUN BIOTECHNOLOGY CO LTD
- Filing Date
- 2024-06-18
- Publication Date
- 2026-06-23
AI Technical Summary
Existing biochar activation methods suffer from high energy consumption and chemical pollution, and the treatment of wood vinegar wastewater is difficult, thus failing to be effectively utilized.
Using wood vinegar vapor as an activator, combined with thermochemical and physical processes, and recycling wood vinegar liquid as a heat carrier and reaction participant, energy is provided through thermochemical reactions to achieve biochar activation.
The energy consumption of the biochar activation process has been reduced by more than 60%, chemical pollution has been avoided, the utilization rate of wood vinegar has reached 100%, and production costs have been reduced.
Smart Images
Figure CN118387873B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a steam-based biochar activation process, specifically an energy-saving process for activating biochar using wood vinegar steam via a thermochemical-physical coupling method. Background Technology
[0002] Biomass (agricultural and forestry residues such as branches and fruit shells) can be pyrolyzed to produce charcoal, which can then be activated to obtain bio-activated carbon. However, current activation methods mainly use phosphoric acid or steam methods. The former leads to acid wastewater and acid costs, while the latter causes energy consumption and increases production costs. During biomass charcoal production, a large amount of wood vinegar wastewater is generated. One ton of biomass can produce 300 kg of wood vinegar. Wood vinegar is an aqueous solution containing more than 200 kinds of organic matter, with a water content of about 80-90 wt%, an acetic acid content of about 4-7 wt%, and the rest being oxygen-containing organic compounds. As organic wastewater, its treatment is difficult and costly, becoming a bottleneck in biomass energy development. Comprehensive utilization is necessary, but due to the large volume and low organic matter content of wood vinegar, an effective comprehensive utilization method has not yet been found. Summary of the Invention
[0003] This invention uses wood vinegar steam instead of water vapor as the activator. The wood vinegar liquid is recycled in the process, acting as both a heat carrier and participating in the thermochemical reaction, releasing heat, thus saving energy and reducing emissions—a green new process. Due to the ionization effect of its characteristic component, acetic acid, and conforming to the swelling principle of acid activation, biochar is more easily activated, exhibiting dual benefits—a thermochemical-physical coupling method. Using wood vinegar liquid produced during biomass carbonization as the activator overcomes the high energy consumption problem of single steam activation methods and avoids the chemical pollution problems of single phosphoric acid activation methods. It overcomes the shortcomings of traditional methods, saves energy and reduces emissions, lowers production costs, and effectively realizes the comprehensive utilization of wood vinegar liquid.
[0004] The technical solution of this invention is achieved as follows: an energy-saving process for activating biochar with wood vinegar steam using a thermochemical-physical coupling method.
[0005] a. The biomass is crushed, extruded into granules, and then carbonized at 350-450℃. The heat is supplied by the combustion of biomass waste, which also produces flue gas. The carbonization is an anaerobic pyrolysis, i.e., dry distillation. Under anaerobic conditions, the lignocellulosic raw material is decomposed by heat to produce wood gas (mainly CO and H2, with small amounts of CH4, C2H4, CO2, etc.), low-temperature wood vinegar steam (250-300℃, mainly H2O, CH3COOH, C6H6O, CmHnO, etc.), and biochar. The heat required is supplied by the external combustion of biomass. The biochar generated by pyrolysis will enter the next step of activation.
[0006] b. The low-temperature wood vinegar steam (mainly composed of H2O, CH3COOH, C6H6O, CmHnO, etc.) generated by carbonization at 250-300℃ and wood gas (mainly composed of CO and H2, and small amounts of CH4, C2H4, CO2, etc.) are simultaneously combusted and mixed with the newly introduced air; the low-temperature wood vinegar steam reacts and is heated to become high-temperature mixed steam (800-850℃), releasing heat at the same time;
[0007] c. Use 800-850℃ high-temperature mixed steam (mainly CO2 and H2O) as an activating agent to activate biochar for 30-60 minutes to obtain bio-activated carbon; this reaction is endothermic, and the energy required is supplied by the previous step.
[0008] d. New CO and H2 are generated and used as medium-temperature mixed steam (500-600℃) to heat a small amount of wood vinegar liquid that has been sprayed and humidified, turning it into low-temperature wood vinegar mixed steam (mainly composed of CO and H2) at 250-300℃. This mixture is then circulated into combustion and mixing, generating new heat and producing activators in a cyclical manner.
[0009] Furthermore, the thermal cracking reaction equation for the carbonization process in step a is as follows:
[0010] (1)CHxOy →(1-y)C +y / 2 CO +x / 2H2 + y / 2m C m H n O.
[0011] Furthermore, in step b, the main exothermic combustion reaction equation is as follows:
[0012] (2) 2CO + 0.5O2 = CO2 -Q
[0013] (3) H2 + 0.5O2 = H2O -Q
[0014] (4) CO + H2 = CH4 + H2O -Q
[0015] (5) CmHnO + (m+n / 4)O2 → mCO2 + (n / 2)H2O -Q.
[0016] Furthermore, in step c, the activation endothermic reaction equation is as follows:
[0017] (6) C + 2H₂O = 2H₂ + CO₂ + Q
[0018] (7) C + H₂O = H₂ + CO + Q
[0019] (8) C + CO2 = 2CO + Q.
[0020] Furthermore, the biomass is crushed to 200-300 mesh, extruded into 5mm particles, and then carbonized at 400℃.
[0021] Furthermore, the biomass is agricultural and forestry residues such as tree branches and fruit shells.
[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention uses wood vinegar steam instead of water steam as the activator. The wood vinegar liquid is recycled in the process, acting as both a heat carrier and participating in the thermochemical reaction, releasing heat, thus saving energy and reducing emissions. It is a green new process with energy savings of over 60%, 100% utilization of wood vinegar liquid, and no waste discharge. Due to the ionization effect of its characteristic component acetic acid, which conforms to the swelling principle of acid activation, biochar is more easily activated, possessing dual functions and representing a thermochemical-physical coupling method. Using wood vinegar liquid produced during biomass carbonization as the activator overcomes the high energy consumption problem of the single water steam activation method and avoids the chemical pollution problem of the single phosphoric acid activation method. It overcomes the shortcomings of traditional methods, saves energy and reduces emissions, lowers production costs, and effectively realizes the comprehensive utilization of wood vinegar liquid. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.
[0024] Figure 1 This is a flow chart of an energy-saving and emission-reduction process for activating biochar with wood vinegar steam using a thermochemical-physical coupling method. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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. Example 1
[0026] One ton of Quercus acutissima branches (pre-dried to a moisture content of less than 15%) are crushed to 20-30 mesh (75 kWh electricity), extruded into 5 mm particles (75 kWh electricity), and then carbonized at a temperature of 350℃ (heated by burning biomass waste, consuming 50 kWh electricity). This produces wood gas, low-temperature wood vinegar steam, and biochar. The wood gas and low-temperature wood vinegar steam are simultaneously combusted and mixed with newly introduced air. The low-temperature wood vinegar steam reacts and is heated to become high-temperature mixed steam (800-850℃), whose main components are CO2 and H2O. This mixture is used as an activator to activate the biochar for 30 minutes, resulting in Quercus acutissima activated carbon. The process generates new CO and H2, which, as medium-temperature mixed steam (500-600℃), heats a small amount of sprayed and humidified wood vinegar solution to become low-temperature wood vinegar mixed steam (250-300℃), mainly composed of CO and H2. This steam circulates back into the combustion mixture, generating new heat and producing an activator that continuously activates the Quercus acutissima charcoal into activated Quercus acutissima carbon. 148 kg of activated Quercus acutissima carbon was obtained, with an iodine value of 840 mg / g and a methylene blue adsorption value of 136 mL / g, meeting the standards for wood-based activated carbon. Furthermore, the main energy required for the entire activation process comes from the heat of the chemical reaction and the heat transfer of the wood vinegar steam, consuming only 30 kWh of electricity. The total power consumption is 230 kWh (828 * 10). 3 kJ) and energy consumption of steam activation method (1368*10) 3 Compared to kJ, it saves 65.2% of energy. 100% of the oak wood vinegar produced during the carbonization process is effectively utilized, with no waste liquid generated. See Table 1. Example 2
[0027] One ton of jujube branches (pre-dried to a moisture content of less than 15%) are crushed to 20-30 mesh (75 kWh electricity), extruded into 5 mm particles (75 kWh electricity), and then carbonized at a temperature of 400℃ (heated by burning biomass waste, consuming 50 kWh electricity). This produces wood gas, low-temperature wood vinegar steam, and biochar. The wood gas and low-temperature wood vinegar steam are simultaneously combusted and mixed with newly introduced air. The low-temperature wood vinegar steam reacts and is heated to become high-temperature mixed steam (800-850℃), whose main components are CO2 and H2O. This mixture is used as an activator to activate the jujube charcoal for 45 minutes, resulting in jujube activated carbon. The process generates new CO and H2, which, as medium-temperature mixed steam (500-600℃), heats a small amount of sprayed and humidified wood vinegar solution to become low-temperature wood vinegar mixed steam (250-300℃), mainly composed of CO and H2. This steam circulates back into the combustion mixture, generating new heat and continuously producing activators to activate jujube charcoal into jujube activated carbon. 130 kg of jujube activated carbon was obtained, with an iodine value of 848 mg / g and a methylene blue adsorption value of 140 mL / g, meeting the standards for wood-based activated carbon. Furthermore, the main energy required for the entire activation process comes from the heat of chemical reaction and the heat transfer of the wood vinegar steam heat carrier, consuming only 35 kWh of electricity. The total power consumption is 235 kWh (846 * 10). 3 kJ) and energy consumption of steam activation method (1386*10) 3 Compared to kJ, it saves 63.8% of energy. 100% of the jujube wood vinegar produced during the carbonization process is effectively utilized, with no waste liquid generated. See Table 1. Example 3
[0028] One ton of walnut shells (pre-dried to a moisture content of less than 15%) are crushed to 20-30 mesh (75 kWh electricity), extruded into 5 mm particles (75 kWh electricity), and then carbonized at a temperature of 450℃ (heated by burning biomass waste, consuming 50 kWh electricity). This produces wood gas, low-temperature wood vinegar steam, and biochar. The wood gas and low-temperature wood vinegar steam are simultaneously combusted and mixed with newly introduced air. The low-temperature wood vinegar steam reacts and is heated to become high-temperature mixed steam (800-850℃), whose main components are CO2 and H2O. This mixture is used as an activator to activate the walnut charcoal for 60 minutes, resulting in walnut activated carbon. The process generates new CO and H2, which, as medium-temperature mixed steam (500-600℃), heats a small amount of sprayed and humidified wood vinegar solution to become low-temperature wood vinegar mixed steam (250-300℃), mainly composed of CO and H2. This steam circulates back into the combustion mixture, generating new heat and continuously producing activating agents to activate walnut charcoal into walnut activated carbon. 110 kg of walnut activated carbon was obtained, with an iodine value of 852 mg / g and a methylene blue adsorption value of 144 mL / g, meeting the standards for wood-based activated carbon. Furthermore, the main energy required for the entire activation process comes from the heat of chemical reaction and the heat transfer of the wood vinegar steam heat carrier, consuming only 36 kWh of electricity. The total power consumption is 236 kWh (850 * 10). 3 kJ) and energy consumption of steam activation method (1391 * 10) 3 Compared to kJ, it saves 63.6% of energy. 100% of the walnut wood vinegar produced during the carbonization process is effectively utilized, with no waste liquid generated. See Table 1.
[0029] Table 1. Comparison of energy-saving and emission-reduction examples of biochar activation using wood vinegar steam (processing 1 ton of biomass)
[0030]
[0031] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. An energy-saving process for activating biochar with wood vinegar steam using a thermochemical-physical coupling method, characterized in that, a. Crush the biomass, compress it into pellets, and then carbonize it at 350-450℃; b. The low-temperature wood vinegar vapor and wood gas produced by carbonization, with a temperature of 250-300℃ and main components of H2O, CH3COOH, C6H6O, and CmHnO, are simultaneously combusted and mixed with newly introduced air. The low-temperature wood vinegar vapor reacts and is heated to become a high-temperature mixed steam with a temperature of 800-850℃ and main components of CO2 and H2O. The main components of the wood gas are CO and H2, with small amounts of CH4, C2H4, and CO2. c. Use 800-850℃ high-temperature mixed steam as an activating agent to activate biochar for 30-60 minutes to obtain bio-activated carbon; d. The newly generated 500-600℃ CO and H2, as medium-temperature mixed steam, heats a small amount of wood vinegar liquid that has been sprayed and humidified, turning it into low-temperature wood vinegar mixed steam with CO and H2 as the main components at 250-300℃. This mixed steam is then circulated into the combustion mixture, generating new heat and circulating to produce activators.
2. The energy-saving process for activating biochar with wood vinegar steam using the thermochemical-physical coupling method according to claim 1, characterized in that, The thermal cracking reaction equation for the carbonization process in step a is as follows: (1)CHxOy →(1-y)C +y / 2 CO +x / 2H2 + y / 2m C m H n O。 3. The energy-saving process for activating biochar with wood vinegar steam using the thermochemical-physical coupling method according to claim 1, characterized in that, In step b, the main exothermic combustion reaction equation is as follows: (2) CO + 0.5O2 = CO2 -Q (3) H2 + 0.5O2 = H2O -Q (4) CO + 3H₂ = CH₄ + H₂O -Q (5) CmHnO + (m+n / 4)O2 → mCO2 + (n / 2)H2O.
4. The energy-saving process for activating biochar with wood vinegar steam using the thermochemical-physical coupling method according to claim 1, characterized in that, In step c, the activation endothermic reaction equation is as follows: (6) C + 2H₂O = 2H₂ + CO₂ + Q (7) C + H₂O = H₂ + CO + Q (8) C + CO2 = 2CO + Q.
5. The energy-saving process for activating biochar with wood vinegar steam using the thermochemical-physical coupling method according to claim 1, characterized in that, The biomass is crushed to 200-300 mesh, extruded into 5mm particles, and then carbonized at 400℃.
6. The energy-saving process for activating biochar with wood vinegar steam using the thermochemical-physical coupling method according to claim 1, characterized in that, The biomass refers to agricultural and forestry residues such as tree branches and fruit shells.