Method for separating whole components of lignocellulosic biomass using a two-phase system

Abstract

The application discloses a method for separating lignocellulose biomass by using a two-phase system, wherein mixed organic solvents are used as the organic phase, dilute sulfuric acid is used as the water phase, and the lignocellulose biomass is separated into three phases in an autoclave under certain conditions, and then the solid phase rich in cellulose, the organic phase containing lignin and the water phase containing xylose are obtained by filtration and liquid separation. The mixed organic solvents are selected from any one of acetone and amyl alcohol, and a mixed solution of phenol and amyl alcohol. The method has the advantages of low reaction temperature, short processing time, recycling of xylose as a conversion product of hemicellulose, and simultaneous realization of efficient separation or conversion of three main components of lignocellulose biomass.

Description

Technical Field

[0001] This invention belongs to the field of lignocellulosic biomass separation and conversion technology, specifically relating to a method for the complete separation of lignocellulosic biomass components using a two-phase system. Background Technology

[0002] Lignocellulose biomass has attracted widespread attention due to its renewability. It is mainly composed of three parts: lignin, cellulose, and hemicellulose. These components are interconnected, forming a dense three-dimensional structure, which makes it difficult to efficiently utilize the various components of the biomass. Therefore, effective pretreatment and separation / conversion methods are crucial for achieving efficient utilization of lignocellulose biomass.

[0003] In recent years, the use of organic solvents to separate lignocellulose has attracted widespread attention. Compared with other separation methods, the main advantages of organic solvent methods are that they can reduce the viscosity of the separation medium and improve the permeability of biomass. Furthermore, compared with ionic liquids and eutectic solvents, organic solvents are simple to use and do not require additional preparation processes. Organic solvents are generally classified into single-phase and two-phase systems based on the solution state. While single-phase systems offer higher separation efficiency, they cannot effectively retain other components during separation, which is detrimental to subsequent component separation and value-added utilization. In contrast, although two-phase systems have lower separation efficiency due to mass transfer, by using appropriate combinations of organic solvents, the complete separation of lignocellulose biomass can be achieved under mild conditions, which is more conducive to improving the utilization efficiency of biomass feedstock.

[0004] Currently, much research focuses on finding suitable organic solvents for the efficient separation of lignocellulosic biomass, and further producing high-value biomass-based chemicals such as cellulose nanocrystals, furfural, and phenolic monomers. For example, Chinese invention patent CN106674538A discloses a method for separating and extracting plant biomass components. This method uses an acid solution and γ-pentanolide to form a two-phase system to obtain high-purity cellulose and lignin. Chinese invention patent CN110004756A discloses a method using a mixed organic solvent composed of acetone and ethylene glycol, with concentrated sulfuric acid as a catalyst, at 120°C with microwave-assisted reaction for 20 min, achieving a lignin recovery rate of 72.24%. Meysam et al. also reported a method using 5% mannitol to assist in the synergistic separation of lignin from a p-toluenesulfonic acid / pentanol system, achieving a lignin separation rate of approximately 90% at 120°C for 40 min. Further processing yields glucose and furfural. (Madadi, M., et al., Sustainable lignocellulose fractionation by integrating p-toluenesulfonic acid / pentanol pretreatment with mannitol for efficient production of glucose, native-like lignin, and...) furfural.BioresourTechnol,2023.371:p128591).

[0005] Meanwhile, current research on the separation of biomass components using organic solvents primarily focuses on improving the separation efficiency of a specific lignocellulosic biomass component. This often involves using harsh reaction conditions or incorporating multi-step pretreatment processes, increasing energy consumption and leading to significant waste of other components of the biomass feedstock. Therefore, a method capable of simultaneously achieving the separation / conversion of all components of lignocellulosic biomass has attracted widespread attention. Summary of the Invention

[0006] This invention is based on the following project: Project Type: National Key Research and Development Program; Project Name: Technology for Preparing High Value-Added Bioproducts from Pyrolysis By-products and Agricultural Straw via Catalytic Hydrolysis; Project Number: 2022YFC3902504. Addressing the aforementioned needs, the aim is to provide a method for the complete separation of lignocellulosic biomass using a two-phase system, simultaneously achieving efficient separation / conversion of the three main components of lignocellulosic biomass and improving resource utilization.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] The present invention provides a method for the complete separation of lignocellulose biomass using a two-phase system, summarized as follows: A mixed organic solvent is used as the organic phase, and dilute sulfuric acid as the aqueous phase. The lignocellulose biomass is separated into its complete components in an autoclave under specific conditions. Through filtration and separation, a cellulose-rich solid phase, a lignin-containing organic phase, and a xylose-containing aqueous phase are obtained. The mixed organic solvent is selected from any one of acetone and pentanol, or a mixture of phenol and pentanol.

[0009] Preferably, the specific separation steps are as follows:

[0010] (1) Add biomass raw materials, aqueous phase and organic phase to the reaction vessel and react at 120-160℃ for 20-60 min; after the reaction is completed, cool to room temperature and take out the reaction solution;

[0011] (2) Filter the reaction solution to obtain residue and filtrate; wash the residue with deionized water until neutral to obtain a cellulose-rich solid; separate the filtrate after standing to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a xylose-rich solution; add the organic phase to anhydrous ethanol to obtain lignin precipitate, filter to obtain lignin.

[0012] Preferably, the raw material for lignocellulosic biomass is 20-60 mesh.

[0013] Further preferably, the volume ratio of acetone or phenol to pentanol is 1:4 to 4:1. Within this range, the cellulose retention rate is at least 80%, the hemicellulose separation rate is higher than 95%, the xylose yield is higher than 35%, and the lignin separation rate is higher than 65%.

[0014] Further preferably, the concentration of dilute sulfuric acid is 0.6% to 1.0% (preferably 0.8%), and the volume ratio between the dilute sulfuric acid solution and the organic phase solution is 1:1.

[0015] Further optimization is achieved by setting the liquid-to-solid ratio between the total mixed liquor and the lignocellulosic biomass to be 10–20:1.

[0016] The formula for calculating the yield RY of solid residue in the separated biomass components is as follows:

[0017]

[0018] In the formula: RY is the yield of solid residue; m 残渣 For residue mass, g; m 原料 The weight of the raw material is in grams (g).

[0019] The cellulose retention rate:

[0020]

[0021] In the formula: RY is the yield of solid residue; CY is the cellulose retention rate; CC 残渣 The cellulose content in the residue, wt%; CC 原料 The cellulose content in the raw material is expressed in wt%.

[0022] The lignin separation rate:

[0023]

[0024] In the formula: RY is the yield of solid residue; LR is the lignin separation rate; LC 残渣 Lignin content in residue, wt%; LC 原料 The lignin content in the raw material is expressed in wt%.

[0025] The hemicellulose separation rate:

[0026]

[0027] In the formula: RY is the yield of solid residue; HR is the hemicellulose separation rate; HC 残渣 The content of hemicellulose in the residue, wt%; HC 原料 The content of hemicellulose in the raw material is expressed in wt%.

[0028] The xylose yield:

[0029]

[0030] In the formula: XY is the yield of xylose in the aqueous phase; XW is the mass of xylose in the aqueous phase, in g; HC 原料 The content of hemicellulose in the raw material is expressed in wt%.

[0031] The optimal separation conditions of this invention are as follows: reaction temperature: 140℃, reaction time: 40 min, stirring speed: 400 rpm; concentration of dilute sulfuric acid: 0.8%, volume ratio of dilute sulfuric acid solution to organic phase solution: 1:1, volume ratio of acetone to pentanol: 2:3, and liquid-solid ratio of total mixture to biomass feedstock: 20:1. This maximizes the retention of xylose yield, resulting in a cellulose retention rate of 87.52%, a hemicellulose separation rate of 98.63%, a xylose yield of 70.44%, and a lignin separation rate of 86.43%.

[0032] Beneficial technical effects of the present invention:

[0033] In terms of yield, this invention is a one-step method for the simultaneous separation / conversion of the three main components of lignocellulosic biomass. The cellulose retention rate is 87.52%, the hemicellulose xylose yield is 70.44%, and the lignin removal rate is 86.43%. This reduces the degradation of cellulose and hemicellulose during the pretreatment process and achieves the simultaneous and efficient separation and conversion of all components of lignocellulosic biomass.

[0034] Regarding reaction conditions, the lignocellulosic biomass separation method of the present invention can achieve simultaneous separation / conversion of the three main components of lignocellulosic biomass at a relatively mild reaction temperature and a shorter reaction time, thereby reducing energy consumption in the pretreatment process of lignocellulosic biomass.

[0035] Regarding the consumption of reaction solution, in the method of the present invention, the organic solvent can be recycled, acetone is recovered by rotary evaporation of the filtrate, and after lignin precipitation, ethanol is removed by rotary evaporation and pentanol is recovered.

[0036] In summary, the method of this invention has high separation efficiency and low energy consumption, and has broad application prospects. It is beneficial to achieve the goal of full-component separation and conversion of lignocellulosic biomass and full utilization of each component. The multiphase full-component separation method described in this invention can be applied to the full-component separation / conversion of lignocellulosic biomass, and has certain application prospects. It is beneficial to achieve the goal of full-component separation of biomass raw materials and high-value utilization of each component. Detailed Implementation

[0037] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0038] The following examples use corn stalks from Shanxi Province, China as lignocellulose biomass raw materials. The contents of its three main components were determined by the Panthen washing method, which showed that cellulose was 45.52%, hemicellulose was 21.93%, and lignin was 12.49%.

[0039] Example 1

[0040] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0041] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution to pentanol is 1:1, the liquid-to-solid ratio of the total mixture to the straw is 20:1, the reaction temperature is 140℃, the reaction time is 40 min, the stirring speed is 400 rpm, and after the reaction is completed, the mixture is cooled to room temperature and removed.

[0042] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, where the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain a lignin precipitate, which is then filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0043] Example 2

[0044] The implementation process of Example 2 is the same as that of Example 1, except that the organic phase is phenol instead of pentanol used in Example 1. The results are shown in Table 1.

[0045] Example 3

[0046] The implementation process of Example 3 is the same as that of Example 1, except that the organic phase is phenol / pentanol (2:3) instead of the pentanol used in Example 1. The results are shown in Table 1.

[0047] Example 4

[0048] The implementation process of Example 4 is the same as that of Example 1, except that the organic phase is acetone / pentanol (2:3) instead of the pentanol used in Example 1. The results are shown in Table 1.

[0049] Table 1 describes the separation and transformation of the three components of the biomass feedstock with different organic groups in the systems described in Examples 1-4, as follows:

[0050] Table 1 Comparison of the separation and conversion of the three components of biomass raw materials in Examples 1-4

[0051]

[0052] By comparing Examples 1-4, it can be seen that the mixed organic phase of acetone and pentanol not only retains excellent lignin separation and cellulose retention efficiency, but also has better selectivity for converting hemicellulose to xylose.

[0053] Example 5

[0054] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0055] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:1:4, the liquid-to-solid ratio of the total mixture to the straw is 20:1, the reaction temperature is 140℃, the reaction time is 40 min, the stirring speed is 400 rpm, and after the reaction is completed, the mixture is cooled to room temperature and removed.

[0056] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0057] Results: Cellulose retention rate was 85.23%, hemicellulose separation rate was 97.21%, xylose yield was 52.40%, and lignin separation rate was 80.54%.

[0058] Example 6

[0059] The implementation process of Example 6 is the same as that of Example 5, except that acetone / pentanol (3:2) is used in the organic phase instead of acetone / pentanol (1:4) used in Example 1. The results are shown in Table 2.

[0060] Example 7

[0061] The implementation process of Example 7 is the same as that of Example 5, except that acetone / pentanol (1:4) is used in the organic phase instead of acetone / pentanol (1:4) used in Example 1. The results are shown in Table 2.

[0062] Table 2 describes the effect of the ratio of acetone to pentanol in the organic phase on the separation and conversion of the three components of the biomass feedstock in the systems described in Examples 4, 5-7:

[0063] Table 2 Comparison of the separation and conversion of the three components of biomass raw materials in Examples 4, 5-7

[0064]

[0065] When the organic phase is acetone / pentanol (2:3), the xylose yield can be maximized, resulting in a cellulose retention rate of 87.52%, a hemicellulose separation rate of 98.63%, a xylose yield of 70.44%, and a lignin separation rate of 86.43%.

[0066] The present invention further verifies the effects of other concentrations of dilute sulfuric acid, reaction temperature, reaction time, and the liquid-to-solid ratio of the total mixture to straw, as detailed in Examples 8-14.

[0067] Example 8

[0068] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0069] The first step involves mixing 20-60 mesh corn stalks, 0.6% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 20:1. The reaction temperature is 140℃, the reaction time is 40 min, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and removed.

[0070] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0071] Results: Cellulose retention rate was 85.62%, hemicellulose separation rate was 99.21%, xylose yield was 53.22%, and lignin separation rate was 86.73%.

[0072] Example 9

[0073] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0074] The first step involves mixing 20-60 mesh corn stalks, 1.0% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 20:1. The reaction temperature is 140℃, the reaction time is 40 min, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and removed.

[0075] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0076] Results: Cellulose retention rate was 91.31%, hemicellulose separation rate was 97.36%, xylose yield was 42.05%, and lignin separation rate was 86.52%.

[0077] Example 10

[0078] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0079] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 20:1. The reaction temperature is 120℃, the reaction time is 40 minutes, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and then removed.

[0080] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, where the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain a lignin precipitate, which is then filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0081] Results: Cellulose retention rate was 95.21%, hemicellulose separation rate was 82.59%, xylose yield was 38.04%, and lignin separation rate was 66.32%.

[0082] Example 11

[0083] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0084] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 20:1. The reaction temperature is 160℃, the reaction time is 40 minutes, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and removed.

[0085] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0086] Results: Cellulose retention rate was 65.01%, hemicellulose separation rate was 98.76%, xylose yield was 55.30%, and lignin separation rate was 93.55%.

[0087] Example 12

[0088] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0089] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, the liquid-to-solid ratio of the total mixture to the straw is 20:1, the reaction temperature is 140℃, the reaction time is 20 min, the stirring speed is 400 rpm, and after the reaction is completed, the mixture is cooled to room temperature and removed.

[0090] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0091] Results: Cellulose retention rate was 95.21%, hemicellulose separation rate was 82.59%, xylose yield was 38.04%, and lignin separation rate was 66.32%.

[0092] Example 13

[0093] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0094] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 20:1. The reaction temperature is 140℃, the reaction time is 60 min, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and then removed.

[0095] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a hemicellulose xylose solution. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0096] Results: Cellulose retention rate was 84.21%, hemicellulose separation rate was 98.55%, xylose yield was 70.30%, and lignin separation rate was 85.66%.

[0097] Example 14

[0098] A method for the complete component separation of lignocellulosic biomass using a two-phase system includes the following steps:

[0099] The first step involves mixing 20-60 mesh corn stalks, 0.8% dilute sulfuric acid solution, acetone, and pentanol in a high-pressure reactor. The volume ratio of dilute sulfuric acid solution, acetone, and pentanol is 5:2:3, and the liquid-to-solid ratio of the total mixture to the straw is 10:1. The reaction temperature is 140℃, the reaction time is 40 min, and the stirring speed is 400 rpm. After the reaction is completed, the mixture is cooled to room temperature and removed.

[0100] The second step involves filtering the mixture to obtain a solid residue and a filtrate. The residue is washed with deionized water until neutral, and the resulting solid is rich in cellulose. The filtrate is rotary evaporated to recover acetone. After standing, the mixture is separated to obtain an organic phase and an aqueous phase, respectively. The aqueous phase is a hemicellulose sugar solution, and the utilization efficiency of hemicellulose is measured by the xylose yield. The organic phase is added to anhydrous ethanol to obtain lignin precipitation, which is filtered and dried in a vacuum drying oven at 50°C for 12 hours to obtain recovered lignin.

[0101] Results: Cellulose retention rate was 80.12%, hemicellulose separation rate was 94.22%, xylose yield was 50.86%, and lignin separation rate was 78.95%.

[0102] The present invention further compares the separation methods and effects in other literature with some embodiments of the present invention, as follows:

[0103] Comparative Example 1

[0104] Example 2 in the patent application with publication number CN115874480A serves as a comparative example of the present invention.

[0105] A highly efficient pretreatment method for biomass in a composite solvent system includes the following steps:

[0106] Step 1: Grind 3g of moso bamboo (40.7% cellulose, 26.7% hemicellulose, 29.9% lignin) and sieve it (100-120 mesh). Place the resulting moso bamboo powder, 60g of propylene carbonate / water composite solvent (propylene carbonate to water mass ratio of 3:2), and 0.15g of p-toluenesulfonic acid into a high-pressure reactor. Step 2: After purging the reactor three times with N2, raise the temperature to 140℃, react for 60 minutes, and maintain a rotation speed of 600 r / min. After the reaction is complete, remove the reactor and let it cool. The mixture was cooled to room temperature and filtered. The third step involved washing the cellulose-rich solid obtained after filtration with 20 mL of propylene carbonate, followed by thorough washing with deionized water until neutral. It was then dried at 105°C to constant weight and weighed for further dehydration to prepare cellulose propylene carbonate. The fourth step involved diluting the collected filtrate with ten times its volume of water, stirring to allow precipitation, and then filtering and drying to obtain a brown powdery solid of lignin-dissociated polyphenols. The propylene carbonate, water, and low-boiling-point organic acid used as a catalyst could all be recovered and reused via vacuum distillation. In this process, the cellulose retention rate in the cellulose-rich solid reached 93.2%, the lignin separation rate reached 88.7%, and the hemicellulose separation rate reached 79.2%.

[0107] Compared with Comparative Example 1, Example 4 showed that it could achieve a lignin separation rate of 86.43% and a hemicellulose separation rate of 98.63% in a reaction time of 40 min, and the hemicellulose was converted into xylose with a yield of 70.44%.

[0108] Comparative Example 2

[0109] Example 2 in the patent application with publication number CN117702522A serves as a comparative example of the present invention.

[0110] Sugarcane bagasse (particle size 40-60 mesh, cellulose 41.96%, hemicellulose 23.84%, lignin 21.40%) was used as raw material. 2g of sugarcane bagasse was weighed and placed in a 75ml pressure-resistant bottle, along with 40ml of ethylene glycol phenyl ether and 0.05mol / L concentrated sulfuric acid. The pressure-resistant bottle was placed in an oil bath and reacted at 110℃ for 60min. After the reaction, the residue and pretreatment liquid were separated and recovered separately using a G3 funnel. The residue was washed with deionized water and ethanol until the pH of the filtrate was equal to 7. This pretreatment removed 90.33% of the lignin and 76.70% of the hemicellulose from poplar wood, retaining 90.47% of the cellulose.

[0111] Eight volumes of isopropyl ether were added to the recovered pretreatment solution, resulting in the formation of a precipitate. The supernatant was recovered after centrifugation. The precipitate was washed with deionized water until non-viscous, then freeze-dried. The recovered powder was lignin, with a recovery rate of 74.29% and a purity of 93.53%. Two volumes of deionized water were added to the recovered supernatant, and the aqueous phase was separated using a separatory funnel. 10 ml of the aqueous phase was taken, and 0.346 ml of 72% sulfuric acid was added. The mixture was placed in an autoclave and reacted at 121°C for 1 hour. The xylose content was measured to be 0.4 mg / ml, resulting in a xylose recovery rate of 60.07%.

[0112] Comparing Example 4 with Comparative Example 2, it was found that Example 4 achieved a lignin separation rate of 86.43% and a hemicellulose separation rate of 98.63% within the reaction time required to simultaneously separate the three biomass components, and the hemicellulose was converted into xylose with a yield of 70.44%. This eliminates the need for the multi-step processing required in Comparative Example 2 to obtain xylose.

[0113] Comparative Example 3

[0114] Example 4 in the patent application with publication number CN106674538A serves as a comparative example of the present invention.

[0115] (1) Preparation of solvent A: A solvent system consisting of γ-valerolactone, acid, and water was prepared, wherein the mass fraction of γ-valerolactone was 90%, the mass fraction of hydrochloric acid was 0.05%, and the remainder was water. (2) Component separation: 3g of bamboo material was used as raw material, and 30mL of solvent A was added. The mixture was heated at 150℃ for 60min. After heating, the mixture was filtered, and the filter residue and filtrate were collected. The filter residue was washed with water and then dried at 105℃ for 4h to obtain cellulose. Sodium chloride solid was added to the filtrate until the solution was saturated, and then it was treated in an ultrasonic instrument until two phases were formed, with the aqueous phase in the lower layer and the γ-valerolactone phase in the upper layer. The two phases were separated, and the aqueous phase was frozen and dried to obtain hemicellulose-degraded sugars. The solvent in the γ-valerolactone phase was evaporated to remove lignin. The yield of cellulose was 70%; the yield of hemicellulose-degraded sugars was 18%; the yield of lignin was 6%, and the purity was 89%.

[0116] Compared with Comparative Example 3, Example 4 can separate the three biomass components under milder conditions. At 140°C for 40 minutes, an 86.43% lignin separation rate and a 98.63% hemicellulose separation rate can be obtained, and the hemicellulose is converted into xylose with a yield of 70.44%.

[0117] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for separating all components of lignocellulosic biomass using a two-phase system, characterized in that, Using a mixed organic solvent as the organic phase and dilute sulfuric acid as the aqueous phase, lignocellulosic biomass was subjected to complete component separation in an autoclave under specific conditions. Through filtration and separation, a cellulose-rich solid phase, a lignin-containing organic phase, and a xylose-containing aqueous phase were obtained. The mixed organic solvent is selected from a mixed solution of acetone and pentanol, wherein the volume ratio of acetone to pentanol is 2:

3. The concentration of the dilute sulfuric acid is 0.8%, and the volume ratio between the dilute sulfuric acid solution and the organic phase solution is 1:

1. The liquid-to-solid ratio between the total mixed liquor and the lignocellulosic biomass is 20:

1. The separation steps are as follows: (1) Add biomass raw materials, aqueous phase and organic phase to the reaction vessel and react at 140℃ for 40-60 min; after the reaction is completed, cool to room temperature and take out the reaction solution; (2) Filter the reaction solution to obtain residue and filtrate; wash the residue with deionized water until neutral to obtain a cellulose-rich solid; separate the filtrate after standing to obtain an organic phase and an aqueous phase, wherein the aqueous phase is a xylose-rich solution; add the organic phase to anhydrous ethanol to obtain lignin precipitate, filter to obtain lignin. The raw material for lignocellulosic biomass is straw.

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