Method for preparing dehydrated sugar-based product and hard carbon negative electrode material by graded pyrolysis of agroforestry waste

Abstract

This invention provides a method for the co-production of dehydrated glycosylated products and hard carbon anode materials from agricultural and forestry waste through graded pyrolysis, belonging to the technical field of agricultural and forestry waste resource utilization and energy storage carbon materials. Using agricultural and forestry waste such as sawdust, reeds, and straw as raw materials, this invention employs a graded process of low-temperature pyrolysis and high-temperature carbonization to convert holocellulose components into dehydrated glycosylated products, which are then condensed and collected, while lignin components are converted into hard carbon anode materials. Differentiated acid treatment pathways are constructed based on the differences in raw material components: lignin-rich biomass undergoes acid-loaded pretreatment and is not acid-washed after pyrolysis; holocellulose-rich biomass undergoes acid-free loaded pyrolysis and is acid-washed to remove ash after pyrolysis. The biochar obtained from both pathways is then carbonized at high temperatures to produce hard carbon anode materials. This invention achieves high-value co-production of all components from agricultural and forestry waste, with a green and low-carbon process, and has promising prospects for large-scale application.

Description

Technical Field

[0001] This invention belongs to the field of efficient utilization of agricultural and forestry waste resources and green preparation technology of energy storage carbon materials, specifically involving a method for preparing dehydrated sugar products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste. Background Technology

[0002] Against the backdrop of global efforts to advance dual-carbon goals and the rapid development of renewable energy systems, agricultural and forestry waste, as a widely available, abundant, and sustainably supplied lignocellulosic biomass resource, has become an important technological direction for high-value and resource-based utilization to alleviate fossil resource shortages, reduce industrial carbon emissions, and improve the ecological environment. Agricultural and forestry waste mainly consists of holocellulose (cellulose and hemicellulose), lignin, and inorganic ash. Holocellulose has relatively low thermal stability, primarily degrading in the 200–400 °C range, and can be directionally converted into high-value oxygen-containing chemicals such as dehydrated glycosyl products. Lignin has higher thermal stability, gradually undergoing aromatization and carbon restructuring above 400 °C, making it an ideal component for preparing hard carbon anode materials.

[0003] Traditional biomass pyrolysis conversion technologies mostly employ a direct, monolithic pyrolysis route, failing to implement tiered and graded utilization based on component differences. This results in the over-pyrolysis of holocellulose components, which can be converted into high-value-added chemicals. Simultaneously, the hard carbon materials obtained from direct high-temperature carbonization exhibit disordered structures, insufficient defects, and poor conductivity, making it difficult to meet the high-rate, long-cycle, and high-stability requirements of sodium-ion batteries. While some technologies incorporate pretreatment steps, they primarily focus on directly removing holocellulose, failing to achieve co-production of high-value chemicals, resulting in significantly lower energy utilization and economic benefits.

[0004] In the controllable preparation of biomass-based hard carbon materials, acid treatment is a core method for improving material performance. Existing technologies mainly fall into two categories: post-pyrolysis acid washing and acid loading pretreatment. For herbaceous biomass rich in cellulose and hemicellulose (such as reeds and straw), post-pyrolysis acid washing is typically used. Inorganic ash in this type of biomass, such as alkali metals and silicate minerals, forms low-melting-point mineral phases during carbonization, inducing carbon structure melting and sintering, blocking ion transport channels, and reducing material structural stability. Therefore, effective removal is necessary during the preparation process. The core function of acid washing is to remove inorganic ash, amorphous carbon, and small molecule impurities, improving the purity and structural uniformity of biochar, and providing a high-purity precursor for subsequent high-temperature carbonization. For woody biomass rich in lignin (such as sawdust, branches, etc.), it is more suitable to adopt the route of acid loading pretreatment followed by pyrolysis and then carbonization. The acid plays a catalytic role in the pyrolysis process, promoting the directional generation of aromatic structures and realizing in-situ etching, pore formation, defect induction and element doping. Therefore, there is no need for subsequent acid washing, otherwise the active sites and doped components will be removed, reducing the electrochemical performance.

[0005] Current technologies fail to leverage the differences in thermal stability between holocellulose and lignin in biomass to perform pyrolysis at different temperature stages, thus hindering the efficient synergy between the preparation of high-value oxygen-containing chemicals and the synthesis of hard carbon anode materials. Furthermore, they lack differentiated selection criteria for acid washing and acid loading based on the biomass' composition, ash content, and target product requirements. Most processes only achieve single-product preparation, resulting in low atom economy and high energy consumption. Therefore, there is an urgent need to develop a method that can achieve staged pyrolysis to co-produce dehydrated glycosylated products and hard carbon anode materials based on differences in biomass composition. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a method for the co-production of dehydrated glycosylated products and hard carbon anode materials from graded pyrolysis of agricultural and forestry waste. Based on biomass components, it designs differentiated routes, such as acid washing and ash removal after acid-free pyrolysis of acid-loaded biomass and direct carbonization of acid-loaded biomass without acid washing. Through graded pyrolysis co-production technology, it achieves the simultaneous co-production of dehydrated glycosylated products and high-performance hard carbon anode materials, thus achieving the comprehensive effects of full utilization of agricultural and forestry waste resources, maximizing atom economy, green and low-carbon process, and high added value of products.

[0007] In this invention, graded pyrolysis refers to pyrolysis at different temperature stages based on the difference in thermal stability between holocellulose and lignin in biomass, in order to achieve the stepwise conversion and collection of different target products. Based on the graded conversion characteristics of biomass components, this invention sequentially performs low-temperature pyrolysis and high-temperature carbonization: while preparing lignin-rich biochar intermediates during the low-temperature pyrolysis stage, it efficiently enriches and collects dehydrated glycosyl products mainly converted from cellulose and hemicellulose; the resulting lignin-rich precursor is further carbonized at high temperature to obtain high-performance hard carbon anode materials for sodium-ion batteries. This invention also clarifies the applicable scenarios and process boundaries for acid washing and acid loading pretreatment after pyrolysis based on the inherent ash content influence mechanism of biomass and the principle of acid treatment. Among them, an acid-loaded pretreatment route is adopted for lignin-rich biomass, relying on the catalytic dehydration function of acid dopants in the low-temperature pyrolysis stage and the pore-forming, doping, and defect-inducing functions in the high-temperature carbonization stage to achieve dual regulation of carbon structure; for cellulose and hemicellulose-rich biomass, an acid-free loading and subsequent pyrolysis and acid washing route is adopted, which removes inorganic ash and other impurities through acid washing, improves the purity and structural uniformity of biochar, and provides a high-purity precursor for subsequent high-temperature carbonization.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0009] A method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste includes the following steps:

[0010] Step S1: Select agricultural and forestry waste as the initial raw material, remove impurities (such as mud, sand, stones, metal, etc.), wash, dry until the quality is constant, and then crush to obtain biomass powder;

[0011] Step S2: The lignin-rich biomass powder (such as woody biomass like sawdust) obtained in step S1 is impregnated and loaded with an acidic aqueous solution of sulfuric acid, phosphoric acid, or nitric acid. After impregnation, it is not washed and is directly dried until the mass is constant to obtain an acid-loaded biomass precursor.

[0012] Step S3: Place the acid-free biomass powder obtained in step S1 or the acid-loaded biomass precursor obtained in step S2 under an inert protective atmosphere for pyrolysis, condense and collect the pyrolysis volatiles to obtain an oxygen-containing chemical liquid phase product mainly composed of dehydrated sugars, i.e., crude product of dehydrated sugar products, and obtain lignin-rich biochar intermediate after cooling.

[0013] Step S4: The acid-free biochar intermediate obtained in step S3 is soaked in an acid solution to remove ash, washed until neutral and dried to obtain purified biochar; the acid-loaded biochar intermediate obtained in step S3 is not subjected to acid washing and water washing treatment, and the pore structure, defect sites and doping characteristics induced by acid components during pyrolysis are directly retained.

[0014] Step S5: Place the purified biochar or acid-supported biochar intermediate obtained in step S4 under an inert protective atmosphere for carbonization. Heat the system to the target temperature according to the set heating rate and hold it for a certain time. After carbonization, cool it to room temperature under a protective atmosphere to obtain hard carbon anode material.

[0015] Step S6: The liquid phase product collected by pyrolysis in step S3 is separated and purified (by distillation, extraction or chromatographic separation and purification) to obtain the dehydrated glycosylated product.

[0016] In the above scheme, in step S1, the agricultural and forestry waste includes sawdust, reeds and agricultural straw; the drying temperature is 90~110 ℃ and the drying time is 12~36 h.

[0017] Preferably, the drying temperature is 105 °C and the drying time is 24 h.

[0018] In the above scheme, in step S2, the impregnation loading is carried out under stirring conditions and supplemented by ultrasonic dispersion treatment, with an ultrasonic time of 10~120 min; the acid loading in the acidic aqueous solution is 0%~10% based on the dry mass of biomass; the drying temperature is 60~70 ℃ and the drying time is 12~36 h.

[0019] Preferably, the acidic aqueous solution is any one of H2SO4, H3PO4, and HNO3.

[0020] Preferably, the acid loading is 5%, the ultrasonic time is 90 min, the drying temperature is 70 ℃, and the drying time is 24 h.

[0021] In the above scheme, in step S3, the pyrolysis is rapid pyrolysis with a heating rate of 5~50 ℃ / s; the inert protective gas is nitrogen or argon with a gas flow rate of 100~300 mL / min; the pyrolysis temperature is 200~400 ℃; and the reaction residence time is 1~600 s.

[0022] Preferably, the inert protective gas is nitrogen, the gas flow rate is 200 mL / min, the pyrolysis temperature is 300 ℃, the pyrolysis heating rate is 10 ℃ / s, and the reaction residence time is 300 s.

[0023] In the above scheme, in step S4, the acid solution used for ash removal is a mixed aqueous solution of hydrochloric acid and hydrofluoric acid with a mass ratio of 4:1 and a concentration of 2 mol / L. The soaking and stirring time is 24 h. The washing is carried out alternately with deionized water and anhydrous ethanol until the filtrate is neutral.

[0024] In the above scheme, in step S5, the inert protective gas is nitrogen or argon, the gas flow rate is 100~300 mL / min, the heating rate is 1~10 ℃ / min, the carbonization target temperature is 900~1600 ℃, and the holding time is 60~600 min.

[0025] Preferably, the target temperature is 1400 ℃ and the holding time is 120 min.

[0026] In the above scheme, in step S5, the tubular furnace reactor cavity used for carbonization is lined with Hastelloy or corundum ceramic; the sulfuric acid or phosphoric acid remaining in the precursor decomposes and releases sulfur- or phosphorus-containing gaseous intermediates at 250~400 ℃, which are continuously diluted and discharged by inert carrier gas.

[0027] In the above scheme, step S1, after pulverization, further includes the steps of grinding and sieving to obtain biomass powder with uniform particle size; after step S5, it further includes the step of grinding and sieving the obtained hard carbon anode material to obtain anode material powder with uniform particle size that can be used in sodium-ion batteries.

[0028] A hard carbon anode material is prepared by a method for preparing dehydrated glycosylated products and hard carbon anode materials through graded pyrolysis of agricultural and forestry waste. The hard carbon anode material uses lignin-rich components as a matrix and is used as a sodium-ion battery anode material, exhibiting stable sodium storage performance and cycle characteristics.

[0029] A dehydrated glycosyl product is prepared according to a method for preparing dehydrated glycosyl products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste. The dehydrated glycosyl product comprises L-glucan and L-mannan. The crude dehydrated glycosyl product contains 10% to 25% L-glucan by mass, 5% to 20% L-mannan by mass, and the mass ratio of L-glucan to L-mannan is 1.1:1 to 3:1. The total mass percentage of the two components is 15% to 45%.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. This invention utilizes the difference in thermal stability between holocellulose and lignin in biomass, through low-temperature pyrolysis and high-temperature carbonization.

[0032] The grading process converts holocellulose components into dehydrated glycosylated products and lignin components into hard carbon anode materials, which can improve the atom economy and utilization efficiency of biomass resources.

[0033] 2. This invention, through a staged process design of low-temperature pyrolysis and high-temperature carbonization, can reduce overall reaction energy consumption and system energy consumption.

[0034] This reduces energy consumption, shortens reaction time, and decreases the emission of byproducts during pyrolysis and carbonization.

[0035] 3. This invention can adjust the dehydrated glycosylated products by controlling the type and amount of acid loading, pyrolysis parameters, and carbonization parameters.

[0036] Composition and yield, as well as the microstructure and electrochemical performance of hard carbon anode materials, are adapted to the performance requirements of different application scenarios.

[0037] 4. Based on the differences in biomass composition, this invention employs acid loading pretreatment on lignin-rich biomass and then directly followed by pyrolysis.

[0038] Carbonization is then performed on biomass rich in holocellulose using acid-free loaded pyrolysis followed by acid washing to remove ash, reducing carbon structure sintering caused by ash and loss of active sites caused by repeated acid washing. Attached Figure Description

[0039] Figure 1 This is the GCD curve of a sodium-ion half-cell obtained by testing in the Blue Electricity Test System in Embodiment 1 of the present invention. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials used in the following embodiments are commercially available.

[0041] Example 1: Preparation of hard carbon anode material based on waste reeds and its application in sodium-ion batteries

[0042] A method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste includes the following steps:

[0043] Step S1: Take waste reed powder as agricultural and forestry waste raw material, remove impurities such as mud, sand and stones manually, rinse repeatedly with deionized water until the surface is clean, place it in a constant temperature drying oven, dry at 90 ℃ for 24 h until the powder quality remains constant, complete the raw material drying pretreatment, and then crush it to obtain reed biomass powder.

[0044] Step S2: In this embodiment, an acid-free loading process is used, without acid impregnation loading, and the next step of pyrolysis is carried out directly.

[0045] Step S3: Place the reed biomass powder obtained in Step S1 into a closed tubular pyrolysis reactor, continuously introduce high-purity nitrogen as a protective atmosphere, maintain a stable gas flow rate of 200 mL / min, and uniformly heat to 400℃ at a heating rate of 10℃ / s, with a reaction residence time of 300s. During the pyrolysis process, use circulating brine below 0℃ to condense and collect the pyrolysis volatiles, obtaining a liquid-phase product of oxygen-containing chemicals mainly composed of dehydrated sugars, i.e., the crude product of dehydrated glycosylated products; after the pyrolysis process is completed, allow it to cool naturally to room temperature under a nitrogen atmosphere to obtain a lignin-rich reed-based pyrolytic biochar intermediate.

[0046] Step S4: The acid-free reed-based pyrolytic biochar intermediate obtained in step S3 is soaked and stirred in a mixed aqueous solution of hydrochloric acid and hydrofluoric acid with a concentration of 2 mol / L and a mass ratio of 4:1 for 24 h to remove inorganic ash and metal impurities. Then, the solid product is washed alternately with deionized water and anhydrous ethanol until the pH of the supernatant after washing is 7. The washed solid material is then dried in a constant temperature drying oven at 90 ℃ for 24 h to obtain purified biochar.

[0047] Step S5: Transfer the purified biochar obtained in step S4 into a tube furnace, maintain a nitrogen protective atmosphere, with a gas flow rate of 200 mL / min, and uniformly heat to 1400 ℃ at a heating rate of 5 ℃ / min. Carbonize at this temperature for 2 h. After carbonization, cool to room temperature in a nitrogen atmosphere to finally obtain the reed-derived hard carbon anode material.

[0048] Step S6: The liquid phase product (i.e., the crude dehydrated glycosyl product) collected from the pyrolysis in step S3 is separated and purified to obtain the dehydrated glycosyl product. The collected pyrolysis liquid containing dehydrated sugars is analyzed using gas chromatography-mass spectrometry (GC-MS) with online detection. Quantitative analysis by GC showed that the yield of L-glucose was 23.56%, and the yield of L-mannan was 17.43%.

[0049] Electrochemical performance testing of hard carbon anode materials:

[0050] The prepared reed-based hard carbon anode material was assembled into a sodium-ion half-cell, and its electrochemical performance was tested using a Blue Electricity testing system. The test results showed that the material exhibited stable constant-current charge-discharge curves and low polarization in the first three cycles, with a reversible specific capacity of 221 mAh / g and an initial coulombic efficiency of 84%. It possesses excellent sodium-ion storage performance and application potential, and can be used as an anode material for sodium-ion batteries. Figure 1 The constant current charge-discharge (GCD) curve of the sodium-ion half-cell is shown. The first three cycles of the charge-discharge curve are stable, which further verifies that the hard carbon anode material has good sodium storage performance.

[0051] Example 2: Preparation of Sulfuric Acid-Supported Hard Carbon Anode Material Based on Waste Wood Chips

[0052] A method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste includes the following steps:

[0053] Step S1: Take waste wood chip powder as agricultural and forestry waste raw material, remove impurities such as mud, sand and stones manually, rinse repeatedly with deionized water until the surface is clean, place it in a constant temperature drying oven, dry at 105 ℃ for 36 h until the powder quality remains constant, complete the raw material drying pretreatment, and then crush it to obtain wood chip biomass powder.

[0054] Step S2: Acid impregnation and loading of the lignin-rich biomass powder in the sawdust biomass powder obtained in Step S1: Weigh 10 g of dry sawdust powder and place it in a beaker for later use; based on a loading ratio of 5% of the dry weight of sawdust, the required mass of pure sulfuric acid is 0.5 g, i.e., 0.51 g of 98% concentrated sulfuric acid. Weigh 0.51 g of 98% concentrated sulfuric acid, add 50 ml of deionized water to dilute and stir evenly. Slowly add the diluted sulfuric acid solution to the sawdust powder while stirring, and then sonicate at room temperature for 60 min to ensure that the sulfuric acid is fully impregnated and evenly dispersed in the sawdust matrix; after impregnation, do not wash, place the mixture in a constant temperature forced-air drying oven, and dry at 65 ℃ for 24 h until the system mass is constant to obtain a 5% sulfuric acid-loaded sawdust precursor.

[0055] Step S3: The sulfuric acid-doped wood chip precursor obtained in step S2 is placed in a tubular pyrolysis reactor, and high-purity nitrogen gas with a flow rate of 200 mL / min is continuously introduced as a protective atmosphere. The temperature is increased to 300 °C at a heating rate of 20 °C / s, and the reaction residence time is 600 s. The volatile components generated by pyrolysis are recovered by a low-temperature condenser to obtain an oxygen-containing chemical liquid phase product mainly composed of dehydrated sugars, i.e., the crude product of dehydrated sugar products. After pyrolysis, the product is cooled to room temperature under a nitrogen atmosphere to obtain an acid-supported pyrolytic biochar intermediate.

[0056] Step S4: The acid-supported pyrolytic biochar intermediate obtained in step S3 is not subjected to acid washing or water washing. The pore structure, defect sites and doping characteristics induced by the acid components during the pyrolysis process are directly retained for subsequent high-temperature carbonization.

[0057] Step S5: Transfer the acid-loaded pyrolytic biochar obtained in step S4 to a tube furnace, and heat it to 1200 ℃ at a heating rate of 5 ℃ / min under a nitrogen protective atmosphere with a flow rate of 200 mL / min. Carbonize at this temperature for 2 h. After carbonization, cool it to room temperature in an inert atmosphere to obtain the sulfuric acid-loaded wood chip-based hard carbon anode material.

[0058] Step S6: The liquid phase product (i.e., the crude product of dehydrated glycosyl products) collected from the pyrolysis in step S3 is separated and purified to obtain the dehydrated glycosyl products. The collected pyrolysis liquid containing dehydrated sugars is analyzed using gas chromatography-mass spectrometry (GC-MS) with online detection. Quantitative analysis by GC showed that the yield of L-glucose was 13.65%, and the yield of L-mannan was 7.28%.

[0059] Electrochemical performance testing of hard carbon anode materials:

[0060] The prepared wood-based sulfuric acid-supported hard carbon anode material was assembled into a sodium-ion half-cell, and its electrochemical performance was tested using a Blue Electric testing system. The test results showed that, at a current density of 20 mA / g and a voltage range of 0-2V, it exhibited an initial coulombic efficiency of 65% and an initial specific capacity of 242 mAh / g, indicating its suitability as an anode material for sodium-ion batteries.

[0061] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0062] The detailed descriptions listed above are merely specific illustrations of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing dehydrated glycosylated products and hard carbon anode materials through graded pyrolysis of agricultural and forestry waste, characterized in that, Includes the following steps: Step S1: Select agricultural and forestry waste as the initial raw material, remove impurities, wash, dry until the quality is constant, and then crush to obtain biomass powder; Step S2: The lignin-rich biomass powder obtained in step S1 is impregnated and loaded with an acidic aqueous solution of sulfuric acid, phosphoric acid, or nitric acid. After impregnation, it is not washed and is directly dried until the mass is constant to obtain an acid-loaded biomass precursor. Step S3: Place the acid-free biomass powder obtained in step S1 or the acid-loaded biomass precursor obtained in step S2 under an inert protective atmosphere for pyrolysis, condense and collect the pyrolysis volatiles to obtain an oxygen-containing chemical liquid phase product mainly composed of dehydrated sugars, i.e., crude product of dehydrated sugar products, and obtain lignin-rich biochar intermediate after cooling. Step S4: The acid-free biochar intermediate obtained in step S3 is soaked in an acid solution to remove ash, washed until neutral and dried to obtain purified biochar; the acid-loaded biochar intermediate obtained in step S3 is not subjected to acid washing and water washing treatment, and the pore structure, defect sites and doping characteristics induced by acid components during pyrolysis are directly retained. Step S5: Place the purified biochar or acid-supported biochar intermediate obtained in step S4 under an inert protective atmosphere for carbonization. After carbonization, cool to room temperature under a protective atmosphere to obtain hard carbon anode material. Step S6: The liquid phase product collected by pyrolysis in step S3 is separated and purified to obtain the dehydrated glycosylated product.

2. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S1, the agricultural and forestry waste includes sawdust, reeds, and agricultural straw; the drying temperature is 90~110 ℃, and the drying time is 12~36 h.

3. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S2, the impregnation loading is carried out under stirring conditions and supplemented by ultrasonic dispersion treatment for 10-120 min; the acid loading in the acidic aqueous solution is 0%-10% based on the dry mass of biomass; the drying temperature is 60-70 ℃ and the drying time is 12-36 h.

4. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S3, the pyrolysis is a rapid pyrolysis with a heating rate of 5~50 ℃ / s; the inert protective gas is nitrogen or argon with a gas flow rate of 100~300 mL / min; the pyrolysis temperature is 200~400 ℃; and the reaction residence time is 1~600 s.

5. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S4, the acid solution used for ash removal is a mixed aqueous solution of hydrochloric acid and hydrofluoric acid with a mass ratio of 4:1 and a concentration of 2 mol / L. The soaking and stirring time is 24 h. The washing is carried out alternately with deionized water and anhydrous ethanol until the filtrate is neutral.

6. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S5, the inert protective gas is nitrogen or argon, the gas flow rate is 100~300 mL / min, the heating rate is 1~10 ℃ / min, the carbonization target temperature is 900~1600 ℃, and the holding time is 60~600 min.

7. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S5, the tubular furnace reactor cavity used for carbonization is lined with Hastelloy or corundum ceramic; the sulfuric acid or phosphoric acid remaining in the precursor decomposes and releases sulfur- or phosphorus-containing gaseous intermediates at 250~400 ℃, which are continuously diluted and discharged by inert carrier gas.

8. The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to claim 1, characterized in that, In step S1, the pulverization process further includes grinding and sieving to obtain biomass powder with uniform particle size; after step S5, the process further includes grinding and sieving the obtained hard carbon anode material.

9. A hard carbon anode material, characterized in that, The method for preparing dehydrated glycosylated products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to any one of claims 1 to 8, wherein the hard carbon anode material uses lignin-rich components as the matrix.

10. A dehydrated glycosyl product, characterized in that, The dehydrated glycosyl product and hard carbon anode material are prepared by the method for co-producing dehydrated glycosyl products and hard carbon anode materials by graded pyrolysis of agricultural and forestry waste according to any one of claims 1 to 8, wherein the dehydrated glycosyl product comprises L-glucan and L-mannan; the crude dehydrated glycosyl product contains 10% to 25% L-glucan by mass, 5% to 20% L-mannan by mass, the mass ratio of L-glucan to L-mannan is 1.1:1 to 3:1, and the total mass percentage of the two components is 15% to 45%.

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