Method for co-producing high-purity phenolic substances and recyclable high-performance biochar through catalytic pyrolysis of biomass

Abstract

The invention relates to the field of biomass catalytic pyrolysis, and particularly discloses a method for co-producing high-purity phenolic substances and recyclable high-performance biochar through biomass catalytic pyrolysis. And pyrolyzing the dried biomass raw material in a pyrolyzing furnace to obtain primary carbon and volatile components. And conveying the initial charcoal to a reaction furnace for activation modification, and optimizing charcoal preparation parameters by virtue of a machine learning model to obtain high-value charcoal products such as high-performance catalysts and adsorbents. The prepared charcoal is used for carrying out directional catalytic reforming on volatile components, and the reaction conditions are regulated and controlled by virtue of a model, so that the content of target high-value phenolic substances is greatly increased. After use, the biochar with reduced performance is recycled to an activation modification process and activated again, so that cyclic utilization of the biochar is realized. According to the method, the technological process is innovatively reconstructed, parameters are regulated and controlled by means of machine learning, recycling and cyclic utilization of the biochar are achieved, meanwhile, the high-purity phenolic substances and the high-performance biochar are co-produced, and the method has the advantages of being high in cyclic utilization rate, excellent in preparation condition, high in co-production value, wide in applicability and the like.

Description

Technical Field

[0001] This invention relates to the field of biomass catalytic pyrolysis, and specifically discloses a method for the co-production of high-purity phenolic substances and recyclable high-performance biochar through biomass catalytic pyrolysis. Background Technology

[0002] Biomass resource utilization has long been hampered by the dual bottlenecks of low added value and extensive processing. For example, a large amount of biomass either lacks efficient conversion pathways, leading to nutrient loss due to decay in the field, or causes smog pollution and traffic hazards due to open burning, wasting biomass resources and exacerbating ecological pressure. Existing technologies mostly remain at low-level applications such as direct return to the field and simple fuel production, urgently requiring technological innovation to reconstruct the biomass utilization value chain.

[0003] The core challenges in biomass utilization today include: low biochar activity and limited economic value; high catalyst cost and easy deactivation; low economic efficiency of preparation process parameters and reaction conditions; insufficient purification efficiency of bio-oils (especially phenolic substances) and narrow application scenarios; lack of a complete recycling system and low utilization rate of by-products.

[0004] Therefore, how to efficiently, environmentally, and cost-effectively utilize biomass solid waste, develop "high-value, low-carbon, and circular" biomass utilization technologies, and achieve multi-product co-production and economic optimization of preparation conditions have become the core challenges that urgently need to be overcome in this field. Summary of the Invention

[0005] To address the aforementioned shortcomings and improvement needs, this invention aims to develop a method for the co-production of high-purity phenolic substances and recyclable high-performance biochar through biomass catalytic pyrolysis, creating a low-carbon, circular, innovative plant for the co-production of biochar and phenols. This invention solves problems such as narrow applicability, low recycling rate, high energy consumption, and low co-production value in biomass utilization processes.

[0006] To achieve the above objectives, the technical solution adopted in this invention is as follows: using biomass as raw material, adjusting parameters with the help of machine learning prediction models, and preparing high-performance biochar through activation modification process, utilizing the synergistic effect of its pyrrole-N active sites and C=O functional groups to improve phenol selectivity, thereby achieving both directional conversion of biomass and improving the purity of phenolic products.

[0007] This invention focuses on the whole-chain transformation of biomass resources, innovatively constructs a full-chain value-added system of "char production-catalysis-purification-recycling", and creates an innovative carbon-phenol co-production plant. By directionally controlling the pyrolysis path and strengthening the synergistic utilization of products, it realizes the closed-loop value-added of biomass from "solid waste" to "high-value products + energy", overcomes the difficulties of traditional processes, and supports the sustainable development of agricultural solid waste resource utilization.

[0008] To address the issues of low energy consumption and byproduct utilization in the pyrolysis process, the generated non-condensable volatiles are recycled back to the reactor for energy supply, reducing energy consumption while improving system economy. Regarding the low economic efficiency of the preparation process parameters and reaction conditions, machine learning is used to train a predictive model to find the optimal and most economical preparation conditions. For the issue of low utilization value of traditional biochar, a biochar recovery and even modification process has been developed. This allows for not only recycling but also further activation to utilize it as a highly efficient adsorbent material (the adsorption capacity of the 600-WW sample reached 219.06 mg / g), improving the comprehensive utilization rate of biomass (exceeding 95%) while further enhancing economic benefits.

[0009] The core process of the method for co-producing high-purity phenolic substances and recyclable high-performance biochar through biomass catalytic pyrolysis is as follows: Dried biomass feedstock is transported to a pyrolysis furnace via a biomass conveying pipeline, where it undergoes pyrolysis to obtain primary biochar and phenolic volatiles. The primary biochar is activated and modified in an activation reactor to produce a high-performance biochar product. A specific catalyst product is then transferred to a catalytic reactor to perform targeted catalytic reforming on the phenolic volatiles produced by biomass pyrolysis, significantly increasing the content of the target phenolic substances. Preliminary gas-liquid separation is achieved through a condensation device, and finally, high-purity phenolic substances are obtained through a separation and purification device. Biochar whose performance deteriorates in the catalytic reactor is returned to the reactor for reactivation, achieving biochar recycling and recovery. The activation modification and catalytic reforming processes, through the use of machine learning to train predictive models and optimize parameters such as temperature and time, significantly enhance the economic efficiency of the preparation conditions while improving the catalytic and adsorption performance of biochar and the selectivity for phenols.

[0010] The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis in this invention is characterized by comprising the following steps:

[0011] S1: The dried biomass is catalytically pyrolyzed in an oxygen-free environment in a pyrolysis furnace to produce biochar and volatiles rich in phenolic intermediates.

[0012] S2: The volatiles generated in step S1 are subjected to directional catalytic reforming under biochar catalyst conditions. The reaction conditions are controlled by machine learning model to induce demethoxylation and depolymerization reactions, resulting in volatiles with significantly increased content of target high-value phenolic substances.

[0013] S3: The volatile substances obtained in step S2 are passed through a condensation device to achieve preliminary gas-liquid separation. Then, through separation and purification equipment, crude distillation, rectification distillation, centrifugation and other processes, high-purity target high-value phenolic substances are obtained.

[0014] S4: The biochar obtained in step S1 is transferred to an activation reactor, an activator is added and thoroughly mixed, and parameters are adjusted using a machine learning prediction model to carry out an activation modification reaction, improving the pore structure of the biochar, thereby obtaining high-value carbon products such as high-performance catalysts and high-performance adsorbents. Some of these can be used as catalysts in step S2 and can be recycled back to this step after use.

[0015] Optionally, the biomass mentioned in step S1 may be one or more of the following: bamboo shoot shells, sugarcane bagasse, bamboo, eucalyptus waste, poplar wood, various leaves, and various straws.

[0016] Optionally, in step S1, the moisture content of the dried biomass is about 10% of that before drying, the oxygen-free conditions are Ar, N2, etc., the gas flow rate is 50mL / min to 350mL / min, the temperature is between 550℃ and 600℃, and the time is 10min to 40min, so that the main components such as lignocellulose are pyrolyzed, wherein lignin is pyrolyzed to generate phenolic intermediates.

[0017] Optionally, in step S2, the volatiles generated by pyrolysis are mainly composed of aromatics and phenols, the temperature is 500℃~700℃, the mass ratio of catalyst to biomass is 1:20~1:5, and the time is 10min~60min. Under the catalytic action of biochar catalyst, demethoxylation reaction and depolymerization reaction occur, promoting the severing of phenolic cycloalkyl and cycloalkyl branches, and realizing the directional catalytic reforming of volatiles.

[0018] Optionally, in step S2, the high-purity target high-value phenolic substances include, but are not limited to, phenols, cresols, 4-vinylphenol (4-VP), 4-ethylphenol (4-EP), guaiacol and one or more combinations of o- / resorcinol;

[0019] Optionally, in step S3, the volatile components of the high-content target phenols are cooled with liquid nitrogen using a condenser to achieve gas-liquid separation. Then, through processes such as crude distillation, rectification distillation, and centrifugation in a separation and purification device, high-purity target high-value phenols are obtained, such as the 600-WW sample corresponding to a phenol purity ≥92%. Non-condensable gases (such as CO and CH4) are used as fuel for the hot blast stove, achieving energy self-sufficiency.

[0020] Optionally, in step S4, the biochar activation modification involves activating the pyrolyzed primary biochar with compounds such as FeCl3 and nitrogen-containing compounds such as urea at 700℃~900℃. The mass ratio of the activator to the biochar is 1:5~1:2, the atmosphere is Ar, N2, etc., the gas flow rate is 50mL / min~350mL / min, and the temperature is maintained for 60min~180min. The pore structure (5A-30A) is adjusted by acid washing / water washing to obtain high-performance catalysts, adsorbents, etc.

[0021] Optionally, in step S4, the biochar activator includes, but is not limited to, one or more combinations of FeCl3, KOH, CH3COONa, H3PO4, KHCO3, NaHCO3, and CH3COOK; the recycling of the biochar catalyst involves cooling the biochar that does not meet the performance requirements to room temperature (25°C), removing surface impurities by acid washing, and then dynamically adjusting the type and proportion of activator added according to the activity level and requirements, and repeating step S4.

[0022] Optionally, in steps S2 and S4, the core features of machine learning include, but are not limited to, one or more combinations of: straw raw material element content, volatile matter ratio, and pyrolysis temperature; the prediction model is an extreme gradient regression prediction model (XGB).

[0023] Unless otherwise specified, the terms used herein have their ordinary meaning in the context of the art, the subject matter, and the specific context. Some terms used to describe the invention will be discussed elsewhere in this specification to provide additional guidance to those skilled in the art in describing the invention.

[0024] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0025] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0026] (1) High degree of biochar recycling and high biomass utilization rate;

[0027] This invention, through an innovative process flow design and by controlling parameters such as the selection of activators and the temperature ratio in the activation and modification process, produces high-performance biochar catalysts suitable for pyrolysis and catalytic reforming processes in the biomass utilization chain, achieving catalyst self-sufficiency in production. Simultaneously, the innovative process flow design recovers biochar that does not meet performance requirements after catalytic reforming and reactivates it in the activation and modification process, achieving biochar recovery and recycling, significantly improving biochar utilization rate, and realizing a novel comprehensive utilization of biomass raw materials (utilization rate up to 95%). This groundbreaking achievement of catalyst self-sufficiency and high-performance biochar recovery and recycling significantly reduces production costs, promotes deep decarbonization and circularity, and strengthens both ecological and economic benefits, showing broad application prospects in the context of green agricultural development and carbon neutrality.

[0028] (2) By using machine learning to train a prediction model, the preparation conditions can be optimized and made more economical.

[0029] This invention utilizes machine learning methods for data cleaning, removing outliers and duplicate samples to ensure completeness and consistency. Feature engineering is then used to identify strongly correlated variables, reducing redundant information interference. Finally, standardization is employed to unify data dimensions and eliminate differences in magnitude between different features. Five-fold cross-validation is used to repeatedly test model performance, while parameters are adjusted to optimize the model and improve prediction accuracy. Further data analysis is conducted to extract optimal and most economical process conditions, as well as optimal values ​​and ranges for each feature. After confirming the optimal and most economical preparation conditions for the biochar catalyst, a phenol yield prediction model is built with phenolic yield as the target value to optimize the phenolic yield. This significantly improves biochar performance, target phenolic yield, and the economic efficiency of the preparation conditions.

[0030] (3) The products have high value, excellent performance, high purity, and multiple products are produced in a combined manner;

[0031] This invention, through the selection of activators and parameter control in the activation modification process, produces high-value, high-performance biochar products with outstanding surface area and adsorption performance. Part of this product is used in the catalytic reforming process of this invention, directionally catalytically reforming the phenolic volatiles generated from pyrolysis, resulting in demethoxylation and depolymerization reactions, promoting the severing of phenolic cycloalkyl and other cycloalkyl branches, and significantly increasing the content of the target high-value phenolic substances. By co-producing high-performance, high-value biochar and high-purity, high-value classified substances, the products of this invention have a significant advantage in product value compared to traditional methods, namely, high value and co-production. This achieves the co-production of high-performance biochar (e.g., the 600-WW sample has an adsorption capacity of 219.06 mg / g, and the nitrogen-doped carbon has a specific surface area of ​​up to 2100 m²). 2The purpose is to obtain ( / g) and high-purity phenolic substances (such as 600-WW sample corresponding to phenol purity ≥92%).

[0032] (4) Applicable to a wide range of biomass, with broad applicability;

[0033] The method of this invention is applicable to a wide range of biomass, such as bamboo shoot shells, sugarcane bagasse, bamboo, eucalyptus waste, poplar wood, various leaves, and various straws, and has the obvious advantage of wide applicability. Attached Figure Description

[0034] Figure 1 This is a core process diagram of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments; however, this does not limit the invention to the scope of the described embodiments. Embodiments: After understanding the embodiments of this invention, those skilled in the art can make changes and modifications based on the techniques taught in this invention without departing from the spirit and scope of this invention.

[0036] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0037] This invention provides a method for the co-production of high-purity phenolic substances and recyclable high-performance biochar through biomass catalytic pyrolysis, the core process of which is as follows: Figure 1 As shown, it includes the following steps:

[0038] S1: The dried biomass is catalytically pyrolyzed in an oxygen-free environment in a pyrolysis furnace to produce biochar and volatiles rich in phenolic intermediates.

[0039] S2: The volatiles generated in step S1 are subjected to directional catalytic reforming under biochar catalyst conditions. The reaction conditions are controlled by machine learning model to induce demethoxylation and depolymerization reactions, resulting in volatiles with significantly increased content of target high-value phenolic substances.

[0040] S3: The volatile substances obtained in step S2 are passed through a condensation device to achieve preliminary gas-liquid separation. Then, through separation and purification equipment, crude distillation, rectification distillation, centrifugation and other processes, high-purity target high-value phenolic substances are obtained.

[0041] S4: The biochar obtained in step S1 is transferred to an activation reactor, an activator is added and thoroughly mixed, and parameters are adjusted using a machine learning prediction model to carry out an activation modification reaction, improving the pore structure of the biochar, thereby obtaining high-value carbon products such as high-performance catalysts and high-performance adsorbents. Some of these can be used as catalysts in step S2 and can be recycled back to this step after use.

[0042] In some embodiments, the biomass mentioned in step S1 is one or more of the following, including but not limited to bamboo shoot shells, sugarcane bagasse, bamboo, eucalyptus waste, poplar wood, various leaves, and various straws.

[0043] In some embodiments, in step S1, the moisture content of the dried biomass is about 10% of that before drying. The oxygen-free conditions are Ar, N2, etc., with an atmosphere flow rate of 50 mL / min to 350 mL / min, a temperature between 550℃ and 600℃, and a time of 10 min to 40 min, so that the main components such as lignocellulose are pyrolyzed, wherein lignin is pyrolyzed to generate phenolic intermediates.

[0044] In some embodiments, in step S2, the volatiles generated by pyrolysis are mainly aromatic hydrocarbons and phenolic substances, the temperature is 500℃~700℃, the mass ratio of catalyst to biomass is 1:20~1:5, and the time is 10min~60min. Under the catalytic action of biochar catalyst, demethoxylation reaction and depolymerization reaction occur, which promotes the cleavage of phenolic cycloalkyl, cycloalkyl and other branched chains, and realizes the directional catalytic reforming of volatiles.

[0045] In some embodiments, in step S2, the high-purity target high-value phenolic substance includes, but is not limited to, phenols, cresol, 4-vinylphenol (4-VP), 4-ethylphenol (4-EP), guaiacol and one or more combinations of o- / resorcinol;

[0046] In some embodiments, in step S3, the volatile components of the high-content target phenols are cooled with liquid nitrogen using a condenser to achieve gas-liquid separation. Then, through processes such as crude distillation, rectification distillation, and centrifugation in a separation and purification device, high-purity target high-value phenols are obtained, such as the 600-WW sample corresponding to a phenol purity ≥92%. Non-condensable gases (such as CO and CH4) are used as fuel for the hot blast stove, achieving energy self-sufficiency.

[0047] In some embodiments, in step S4, the biochar activation modification involves activating the pyrolyzed primary biochar with compounds such as FeCl3 and nitrogen-containing compounds such as urea at 700℃~900℃. The mass ratio of the activator to the biochar is 1:5~1:2, the atmosphere is Ar, N2, etc., the gas flow rate is 50mL / min~350mL / min, and the temperature is maintained for 60min~180min. The pore structure (5A-30A) is adjusted by acid washing / water washing to obtain high-performance catalysts, adsorbents, etc.

[0048] In some embodiments, in step S4, the biochar activator includes, but is not limited to, one or more combinations of FeCl3, KOH, CH3COONa, H3PO4, KHCO3, NaHCO3, and CH3COOK; the recycling of the biochar catalyst involves cooling the biochar that does not meet the performance requirements to room temperature (25°C), removing surface impurities by acid washing, and then dynamically adjusting the type and proportion of activator added according to the activity level and requirements, and repeating step S4.

[0049] In some embodiments, the core machine learning features in steps S2 and S4 include, but are not limited to, one or more combinations of: straw raw material element content, volatile matter ratio, and pyrolysis temperature; the prediction model is an extreme gradient regression prediction model (XGB).

[0050] The principle of this invention is as follows: After drying, the biomass is transferred to a pyrolysis furnace, where catalytic pyrolysis occurs in a high-temperature and oxygen-free environment. This causes the main components, such as lignocellulose, to decompose into primary biochar and phenol-rich volatiles, with lignin decomposing into phenolic intermediates. The resulting biochar is then activated and modified in an activation reactor with an activating agent to improve its pore structure, thereby obtaining high-value biochar products such as high-performance catalysts and high-performance adsorbents. The resulting high-performance biochar catalyst is used for directional catalytic reforming of the phenol-rich volatiles, involving demethoxylation and depolymerization reactions, promoting the cleavage of phenolic cycloalkyl and cycloalkyl branches, and significantly increasing the content of the target high-value phenolic substances in the volatiles. The resulting high-content target phenolic volatiles undergo preliminary gas-liquid separation in a condensation device, followed by multiple crude distillations, fractionation, and centrifugation processes using a separation and purification device with specific parameter controls to obtain high-purity target high-value phenolic substances such as phenol, cresol, 4-vinylphenol, 4-ethylphenol, and guaiacol. The activation modification and catalytic reforming processes utilize machine learning to train predictive models, optimize parameters such as temperature and time, increase conditional economics, and improve the catalytic and adsorption performance of biochar, as well as phenol selectivity. Biochar with degraded performance after use is recycled back to the activation modification process for reactivation, producing a high-performance modified biochar product that can be recycled through this process. Ultimately, by using machine learning to train predictive models and control parameters, the co-production of high-purity phenols and recyclable high-performance biochar through biomass catalytic pyrolysis has been achieved, solving problems such as narrow applicability, low recycling rate, high energy consumption, and low co-product value in biomass utilization.

[0051] This invention, through an innovative process flow design and by controlling parameters such as the selection of activators and the temperature ratio in the activation and modification process, produces high-performance biochar catalysts suitable for pyrolysis and catalytic reforming processes in the biomass utilization chain, achieving catalyst self-sufficiency in production. Simultaneously, the innovative process flow design recovers biochar that does not meet performance requirements after catalytic reforming and reactivates it in the activation and modification process, achieving biochar recovery and recycling, significantly improving biochar utilization rate, and realizing a novel comprehensive utilization of biomass raw materials (utilization rate up to 95%). This groundbreaking achievement of catalyst self-sufficiency and high-performance biochar recovery and recycling significantly reduces production costs, promotes deep decarbonization and circularity, and strengthens both ecological and economic benefits, showing broad application prospects in the context of green agricultural development and carbon neutrality. It has significant advantages in high biochar recycling and high biomass utilization rate.

[0052] This invention utilizes machine learning methods for data cleaning, removing outliers and duplicate samples to ensure completeness and consistency. Feature engineering is then used to identify strongly correlated variables, reducing redundant information interference. Finally, standardization is employed to unify data dimensions and eliminate differences in magnitude between different features. Five-fold cross-validation is used to repeatedly test model performance, while parameters are adjusted to optimize the model and improve prediction accuracy. Further data analysis is conducted to extract optimal and most economical process conditions, as well as optimal values ​​and ranges for each feature. After confirming the optimal and most economical preparation conditions for the biochar catalyst, a phenolic yield prediction model is built with phenolic yield as the target value to optimize the phenolic yield. This significantly improves biochar performance and target phenolic yield, as well as the economic efficiency of the preparation conditions. It offers the advantages of optimized preparation conditions and significant cost-effectiveness.

[0053] This invention, through the selection of activators and parameter control in the activation modification process, produces high-value, high-performance biochar products with outstanding surface area and adsorption performance. Part of this product is used in the catalytic reforming process of this invention, directionally catalytically reforming the phenolic volatiles generated from pyrolysis, resulting in demethoxylation and depolymerization reactions, promoting the severing of phenolic cycloalkyl and other cycloalkyl branches, and significantly increasing the content of the target high-value phenolic substances. By co-producing high-performance, high-value biochar and high-purity, high-value classified substances, the products of this invention have a significant advantage in product value compared to traditional methods, namely, high value and co-production. This achieves the co-production of high-performance biochar (e.g., the 600-WW sample has an adsorption capacity of 219.06 mg / g, and the nitrogen-doped carbon has a specific surface area of ​​up to 2100 m²). 2 The aim is to produce high-purity phenolic substances (e.g., phenol purity ≥ 92% for the 600-WW sample). This results in products with high value, superior performance, high purity, and the core advantages of multi-product co-production.

[0054] The method of this invention is applicable to a wide range of biomass, such as bamboo shoot shells, sugarcane bagasse, bamboo, eucalyptus waste, poplar wood, various tree leaves, and various types of straw, exhibiting a significant advantage in its broad applicability. It is applicable to a wide range of biomass and has the advantage of wide applicability.

[0055] To illustrate the method of the present invention in more detail, the following specific embodiments are provided for further explanation:

[0056] Example 1:

[0057] Example 1 of this invention discloses a method for the co-production of high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis, such as... Figure 1 As shown, it includes the following steps:

[0058] S1: Take 2g of bamboo shoot shells, crush and dry them to get 10% moisture from the initial state, use Ar atmosphere, gas flow rate of 180mL / min, maintain furnace temperature of 575℃, pyrolyze for 25min to obtain biochar and volatile matter rich in phenolic intermediates.

[0059] S2: The volatiles generated in step S1 are heated at 500℃, with a catalyst-to-biomass mass ratio of 1:5, for 35 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased target high-value phenol content.

[0060] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 185℃ to achieve the purification purpose and obtain high-purity phenol with a purity ≥92%.

[0061] S4: The biochar obtained in step S1 is transferred to a reactor, and FeCl3 and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon: FeCl3: urea = 2:2:1. The mixture is then pyrolyzed again at 800°C under an Ar atmosphere of 180 mL / min for 60 min. The porous carbon is then acid-washed using a dilute hydrochloric acid solution at a concentration of 0.2 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​1700 m². 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0062] Example 2:

[0063] S1: Take 2g of wheat straw, crush and dry it to get 12% moisture from the initial state, use N2 atmosphere, the total gas flow rate is 350mL / min, maintain the furnace temperature at 600℃, pyrolyze for 30min to obtain biochar and volatile matter rich in phenolic intermediates.

[0064] S2: The volatiles generated in step S1 are heated at 550℃, with a catalyst-to-biomass mass ratio of 1:15, for 45 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased target high-value phenol content.

[0065] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 185℃ to achieve the purification purpose and obtain high-purity phenol with a purity ≥85%.

[0066] S4: The biochar obtained in step S1 is transferred to a reactor, and CH3COONa and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon to CH3COONa to urea is 3:2:1. The mixture is then pyrolyzed again at 700°C under a N2 atmosphere of 350 mL / min for 180 min. The porous carbon is then acid-washed using dilute hydrochloric acid at a concentration of 0.15 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​1800 m² / g. 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0067] Example 3:

[0068] S1: Take 2g of sugarcane bagasse, crush and dry it to get 10% moisture from the initial state, use Ar atmosphere, the total gas flow rate is 200mL / min, maintain the furnace temperature at 600℃, pyrolyze for 40min to obtain biochar and volatile matter rich in phenolic intermediates.

[0069] S2: The volatiles generated in step S1 are heated at 530℃, with a catalyst-to-biomass mass ratio of 1:10, for 60 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased content of the target high-value 4-EP substances.

[0070] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 218℃ to achieve the purification purpose and produce high-purity 4-EP with a purity ≥90%.

[0071] S4: The biochar obtained in step S1 is transferred to a reactor, and KOH and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon to KOH to urea is 3:3:1. The mixture is then pyrolyzed again at 750°C under an Ar atmosphere of 200 mL / min for 60 min. The porous carbon is then acid-washed using a dilute hydrochloric acid solution with a concentration of 0.45 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​2000 m². 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0072] Example 4:

[0073] S1: Take 2g of corn stalks, crush and dry them to get 10% moisture from the initial state, use N2 atmosphere, the total gas flow rate is 50mL / min, maintain the furnace temperature at 560℃, pyrolyze for 30min to obtain biochar and volatiles rich in phenolic intermediates.

[0074] S2: The volatiles generated in step S1 are heated at 500℃, with a catalyst-to-biomass mass ratio of 1:8, for 40 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased content of the target high-value phenolic substances.

[0075] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 185℃ to achieve the purification purpose and obtain high-purity phenol with a purity ≥93%.

[0076] S4: The biochar obtained in step S1 is transferred to a reactor, and KHCO3 and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon:KHCO3:urea = 2:1:1. The mixture is then pyrolyzed again at 750°C under a N2 atmosphere of 50 mL / min for 65 min. The porous carbon is then acid-washed using dilute hydrochloric acid at a concentration of 0.2 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​1850 m² / g. 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0077] Example 5:

[0078] S1: Take 2g of poplar waste, crush and dry it to get 14% moisture from the initial state, use Ar atmosphere, gas flow rate of 275mL / min, maintain furnace temperature of 550℃, pyrolyze for 30min to obtain biochar and volatile matter rich in phenolic intermediates.

[0079] S2: The volatiles generated in step S1 are heated at 600℃, with a catalyst-to-biomass mass ratio of 1:10, for 45 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased content of the target high-value 4-EP substance.

[0080] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 218℃ to achieve the purification purpose and produce high-purity 4-EP with a purity ≥90%.

[0081] S4: The biochar obtained in step S1 is transferred to a reactor, and NaHCO3 and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon to NaHCO3 to urea is 2:2:1. The mixture is then pyrolyzed again at 700°C under an Ar atmosphere of 275 mL / min for 85 min. The porous carbon is then acid-washed using a dilute hydrochloric acid solution with a concentration of 0.35 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​2100 m². 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0082] Example 6:

[0083] S1: Take 2g of cotton stalks, crush and dry them to get 10% moisture from the initial state, use Ar atmosphere, the total gas flow rate is 300mL / min, maintain the furnace temperature at 550℃, pyrolyze for 20min to obtain biochar and volatiles rich in phenolic intermediates.

[0084] S2: The volatiles generated in step S1 are heated at 500℃, with a catalyst-to-biomass mass ratio of 1:5, for 40 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased content of the target high-value phenolic substances.

[0085] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 185℃ to achieve the purification purpose and produce high-purity phenol with a purity ≥90%.

[0086] S4: The biochar obtained in step S1 is transferred to a reactor, and CH3COOK and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon to CH3COOK to urea is 2:1:1. The mixture is then pyrolyzed again at 700°C under an Ar atmosphere of 300 mL / min for 70 min. The porous carbon is then acid-washed using a dilute hydrochloric acid solution at a concentration of 0.1 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​1900 m². 2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0087] Example 7:

[0088] S1: Take 2g of sugarcane bagasse, crush and dry it to get 10% moisture from the initial state, use Ar atmosphere, the total gas flow rate is 350mL / min, maintain the furnace temperature at 580℃, pyrolyze for 45min to obtain biochar and volatile matter rich in phenolic intermediates.

[0089] S2: The volatiles generated in step S1 are heated at 600℃, with a catalyst-to-biomass mass ratio of 1:15, for 40 minutes. Under the catalytic action of the biochar catalyst, the branch chains of phenolic cycloalkyl and cycloalkyl are broken, and the volatiles are catalytically reformed to obtain volatiles with a significantly increased content of the target high-value 4-EP substance.

[0090] S3: The volatile substances obtained in step S2 are passed through a condenser and cooled with liquid nitrogen to achieve gas-liquid separation. Then, they are subjected to crude distillation, rectification distillation, centrifugation and other processes in a separation and purification device. The separation distillation temperature is 218℃ to achieve the purification purpose and produce high-purity 4-EP with a purity ≥85%.

[0091] S4: The biochar obtained in step S1 is transferred to a reactor, and H3PO4 and urea are added as activators and thoroughly mixed for activation and modification. The ratio of pyrolytic primary carbon to H3PO4 to urea is 3:4:1. The mixture is then pyrolyzed again at 750°C under an Ar atmosphere of 350 mL / min for 120 min. The porous carbon is then acid-washed using a dilute hydrochloric acid solution at a concentration of 0.3 mol / L. After filtration and rinsing with excess deionized water, a high-performance biochar catalyst is obtained. The nitrogen-doped carbon has a specific surface area of ​​1800 m².2 / g, the catalyst in step S2 can be recycled back to this step after use;

[0092] The above embodiments are only for illustrating the technical concept and features of this example, and are intended to enable those skilled in the art to understand the content of this invention and implement it accordingly, but should not be construed as limiting the scope of protection of this invention. All equivalent changes or modifications made according to the spirit and essence of this invention should be covered within the scope of protection of this invention.

Claims

1. A method for the co-production of high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis, characterized in that, It includes the following steps: S1: The dried biomass is catalytically pyrolyzed in an oxygen-free environment in a pyrolysis furnace to produce biochar and volatiles rich in phenolic intermediates. S2: The volatiles generated in step S1 are subjected to directional catalytic reforming under biochar catalyst conditions. The reaction conditions are controlled by machine learning model to induce demethoxylation and depolymerization reactions, resulting in volatiles with significantly increased content of target high-value phenolic substances. S3: The volatile substances obtained in step S2 are passed through a condensation device to achieve preliminary gas-liquid separation. Then, through separation and purification equipment, crude distillation, rectification distillation, centrifugation and other processes, high-purity target high-value phenolic substances are obtained. S4: The biochar obtained in step S1 is transferred to an activation reactor, an activator is added and thoroughly mixed, and parameters are adjusted using a machine learning prediction model to carry out an activation modification reaction, improving the pore structure of the biochar, thereby obtaining high-value carbon products such as high-performance catalysts and high-performance adsorbents. Some of these can be used as catalysts in step S2 and can be recycled back to this step after use.

2. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: The biomass mentioned in step S1 includes, but is not limited to, one or more of the following: bamboo shoot shells, sugarcane bagasse, bamboo, eucalyptus waste, poplar wood, various leaves, and various straws.

3. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S1, the moisture content of the dried biomass is about 10% of that before drying. The oxygen-free conditions are Ar, N2, etc., with an atmosphere flow rate of 50 mL / min to 350 mL / min, a temperature between 550℃ and 600℃, and a time of 10 min to 40 min, so that the main components such as lignocellulose are pyrolyzed, wherein lignin is pyrolyzed to generate phenolic intermediates.

4. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S2, the volatiles generated by pyrolysis are mainly aromatic hydrocarbons and phenolic substances. The temperature is 500℃~700℃, the mass ratio of catalyst to biomass is 1:20~1:5, and the time is 10min~60min. Under the catalytic action of biochar catalyst, demethoxylation reaction and depolymerization reaction occur, which promotes the cleavage of phenolic cycloalkyl and cycloalkyl branches, and realizes the directional catalytic reforming of volatiles.

5. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S2, the high-purity target high-value phenolic substances include, but are not limited to, phenols, cresols, 4-vinylphenol (4-VP), 4-ethylphenol (4-EP), guaiacol, and one or more combinations of o- / resorcinol.

6. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S3, the volatile components of the high-content target phenols are cooled with liquid nitrogen using a condenser to achieve gas-liquid separation. Then, through processes such as crude distillation, rectification distillation, and centrifugation in a separation and purification device, high-purity target high-value phenols are obtained, such as the 600-WW sample corresponding to a phenol purity ≥92%. Non-condensable gases (such as CO and CH4) are used as fuel for the hot blast stove, achieving energy self-sufficiency.

7. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S4, the biochar activation modification involves activating the pyrolyzed primary biochar with compounds such as FeCl3 and nitrogen-containing compounds such as urea at 700℃~900℃. The mass ratio of activator to biochar is 1:5~1:

2. The atmosphere is Ar, N2, etc., with a gas flow rate of 50mL / min~350mL / min. The temperature is maintained for 60min~180min. The pore structure (5A-30A) is adjusted by acid washing / water washing to obtain high-performance catalysts, adsorbents, etc.

8. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In step S4, the biochar activator includes, but is not limited to, one or more combinations of FeCl3, KOH, CH3COONa, H3PO4, KHCO3, NaHCO3, and CH3COOK; the recycling of the biochar catalyst involves cooling the biochar that does not meet the performance requirements to room temperature (25°C), removing surface impurities by acid washing, and then dynamically adjusting the type and proportion of activator added according to the activity level and requirements, and repeating step S4.

9. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis as described in claim 1, characterized in that: In steps S2 and S4, the core features of machine learning include, but are not limited to, one or more combinations of: straw raw material element content, volatile matter ratio, and pyrolysis temperature; the prediction model is an extreme gradient regression prediction model (XGB).

10. The method for co-producing high-purity phenolic substances and recyclable high-performance biochar by biomass catalytic pyrolysis according to any one of claims 1 to 9, and its application in the field of preparing high-performance biochar by biomass pyrolysis and co-producing high-purity, high-value phenolic substances.

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