Method for separating cellulose, lignin and hemicellulose from biomass

Abstract

The invention relates to the technical field of separation, and provides a method for separating cellulose, lignin and hemicellulose.The method comprises the following steps that S1, biomass raw materials and auxiliaries are mixed, cooked and separated, a first liquid mixture and a first solid are obtained, and cellulose is obtained after the first solid is cleaned and subjected to filter pressing; s2, separating the first liquid mixture to obtain a second liquid mixture and hemicellulose; s3, evaporating the second liquid mixture to obtain lignin; the auxiliary agent comprises the following components in parts by weight: 2-16 parts of nano silicon, 2-18 parts of sodium stearate, 2-6 parts of potassium carbonate, 3-8 parts of methoxypolyethylene glycol and 5000 parts of water. According to the technical scheme, the problem of low separation efficiency of cellulose, lignin and hemicellulose in biomass in related technologies is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of separation, in particular to a method for separating cellulose, lignin and hemicellulose from biomass. BACKGROUND

[0002] Biomass resources contain a large amount of fiber components. At present, obtaining cellulose, lignin and hemicellulose (collectively referred to as "three elements") from biomass resources through separation technology is an important research direction for comprehensive utilization of biomass resources. These "three elements" have multiple uses in multiple industrial fields and are indispensable chemical raw materials.

[0003] Lignin, cellulose and hemicellulose have covalent bonds and hydrogen bonds, which are tightly combined, making it difficult to separate them from biomass. Traditionally, in order to separate cellulose, hemicellulose and lignin from biomass, high-concentration lye is used for long-time cooking, which can damage the structure of lignin, hemicellulose and cellulose, resulting in poor separation effect. In addition, the high-concentration alkaline wastewater generated during the separation process causes damage to the ecological environment. Therefore, a method for separating cellulose, lignin and hemicellulose from biomass is proposed, which can improve the recovery rate of cellulose, lignin and hemicellulose in biomass, which is of great significance for expanding the application range of cellulose, lignin and hemicellulose. SUMMARY

[0004] The present application provides a method for separating cellulose, lignin and hemicellulose from biomass, which solves the problem of low separation efficiency of cellulose, lignin and hemicellulose in biomass in the related art.

[0005] The technical scheme of the present application is as follows: The present application provides a method for separating cellulose, lignin and hemicellulose from biomass, which includes the following steps: S1, mixing biomass raw materials with an additive, cooking, and separating to obtain a first liquid mixture and a first solid, and washing and pressure filtering the first solid to obtain cellulose; S2, separating the first liquid mixture to obtain a second liquid mixture and hemicellulose; S3, evaporating the second liquid mixture to obtain lignin; The additive includes the following components by weight: 2-16 parts of nano-silicon, 2-18 parts of sodium stearate, 2-6 parts of potassium carbonate, 3-8 parts of polyethylene glycol monomethyl ether, and 5000 parts of water.

[0006] As a further technical scheme, the weight ratio of sodium stearate to polyethylene glycol monomethyl ether is 1-2:1.

[0007] When the weight ratio of sodium stearate and polyethylene glycol monomethyl ether is 1-2:1, the separation efficiency of cellulose in the biomass can be further improved, and the separation efficiency of lignin and hemicellulose in the subsequent biomass can be further improved.

[0008] As a further technical solution, the nano-silicon is modified nano-silicon, and the modified nano-silicon is obtained by modifying nano-silicon with aromatic amide compounds.

[0009] The surface of the nano-silicon is modified by using aromatic amide compounds, which can make the nano-silicon better dispersed in the additive system, thereby better interacting with cellulose in the biomass raw material, further improving the separation efficiency of cellulose in the biomass, and further improving the separation efficiency of lignin and hemicellulose in the biomass.

[0010] As a further technical solution, the weight ratio of the nano-silicon and the aromatic amide compound is 5-11:1.

[0011] When the weight ratio of the nano-silicon and the aromatic amide compound is 5-11:1, the separation efficiency of cellulose in the biomass can be further improved, and the separation efficiency of lignin and hemicellulose in the subsequent biomass can be further improved.

[0012] As a further technical solution, the aromatic amide compound includes one or more of p-toluenesulfonic acid amide, N-phenyl palmitamide, and N-fluorobenzene sulfonamide, and is preferably N-phenyl palmitamide.

[0013] As a further technical solution, the preparation method of the modified nano-silicon includes the following steps: dissolving the aromatic amide compound in dimethyl sulfoxide, adding the nano-silicon and uniformly dispersing, drying, and obtaining the modified nano-silicon.

[0014] As a further technical solution, the biomass raw material is one or more of corn straw, wheat straw, rice straw, cotton straw, sugarcane straw, weeds, peanut shells, and walnut shells.

[0015] As a further technical solution, the mass-volume ratio of the biomass raw material and the additive is 1:10-30 g / L.

[0016] As a further technical solution, in step S2, the separation includes microfiltration separation and ultra-fine separation, each of which independently uses a ceramic filter membrane; the pressure during the microfiltration separation is 0.2-0.3 MPa; and the pressure during the ultra-fine separation is 0.8-1 MPa.

[0017] As a further technical solution, in step S1, the pressure during the cooking is 3.5-5.5 MPa, and the time is 6-8 min; the pressure during the pressure filtration is 6.5-9.5 MPa, and the time is 10-20 min; in step S3, the temperature during the evaporation is 105-115℃, and the time is 50-80 min.

[0018] The working principle and beneficial effects of the present application are as follows: In the present application, the biomass raw material is mixed with an auxiliary agent, which includes sodium stearate and polyethylene glycol monomethyl ether. The use of both can make the biomass raw material fully infiltrate and disperse in the auxiliary agent, and under the joint action of other components in the auxiliary agent, it helps to destroy the chemical bonds and hydrogen bond interactions between cellulose, hemicellulose and lignin in the biomass, thereby helping the hemicellulose to better separate from the interlinked lignin and hemicellulose. After subsequent separation, the separation efficiency of cellulose, lignin and hemicellulose from the biomass can be improved. In addition, the nanosilicon, as a nanometer auxiliary agent with active sites, dispersed in water, also helps the cellulose to be better dissolved, and at the same time improves the separation efficiency of subsequent hemicellulose and lignin. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] In the following examples and comparative examples, the biomass raw material is corn stalk, containing 30wt% of water; the nanosilicon is nanosilicon with a particle size of 30 nm; the type of polyethylene glycol monomethyl ether is MPEG-1000; the filtration accuracy of the ceramic filter membrane during microfiltration separation is 5 μm; and the filtration accuracy of the ceramic filter membrane during ultrafine separation is 50 nm.

[0021] Example 1 A method for separating cellulose, lignin and hemicellulose from biomass, comprising the following steps: S1, 100.00g of corn stalk is mixed with an auxiliary agent at a mass-volume ratio of 1g:10L, cooked at 3.5MPa for 8min, separated to obtain a first liquid mixture and a first solid, the first solid is washed, pressure filtered at 6.5MPa for 20min to obtain cellulose; S2, after microfiltration separation of the first liquid mixture at 0.2MPa, ultrafine separation is carried out at 0.8MPa to obtain a second liquid mixture and hemicellulose; S3, evaporate the second liquid mixture at 105℃ for 80min to obtain lignin; The auxiliary agent comprises the following components by weight: 2 parts of nano-silicon, 2 parts of sodium stearate, 2 parts of potassium carbonate, 3 parts of polyethylene glycol monomethyl ether, and 5000 parts of water.

[0022] Example 2 A method for separating cellulose, lignin and hemicellulose from biomass comprises the following steps: S1, mix 100.00g of corn stalks with an auxiliary agent at a mass-volume ratio of 1g:20L, cook at 4MPa for 6min, separate to obtain a first liquid mixture and a first solid, wash the first solid, and press filter at 8MPa for 15min to obtain cellulose; S2, after microfiltration separation of the first liquid mixture at 0.3MPa using a ceramic filter membrane, perform ultra-fine separation at 0.9MPa to obtain a second liquid mixture and hemicellulose; S3, evaporate the second liquid mixture at 110℃ for 70min to obtain lignin; The auxiliary agent comprises the following components by weight: 12 parts of nano-silicon, 5 parts of sodium stearate, 4 parts of potassium carbonate, 7 parts of polyethylene glycol monomethyl ether, and 5000 parts of water.

[0023] Example 3 A method for separating cellulose, lignin and hemicellulose from biomass comprises the following steps: S1, mix 100.00g of corn stalks with an auxiliary agent at a mass-volume ratio of 1g:30L, cook at 5.5MPa for 6min, separate to obtain a first liquid mixture and a first solid, wash the first solid, and press filter at 9.5MPa for 10min to obtain cellulose; S2, after microfiltration separation of the first liquid mixture at 0.3MPa using a ceramic filter membrane, perform ultra-fine separation at 1MPa to obtain a second liquid mixture and hemicellulose; S3, evaporate the second liquid mixture at 115℃ for 50min to obtain lignin; The auxiliary agent comprises the following components by weight: 16 parts of nano-silicon, 18 parts of sodium stearate, 6 parts of potassium carbonate, 8 parts of polyethylene glycol monomethyl ether, and 5000 parts of water.

[0024] Example 4 The difference between the present example and Example 2 is that in the present example, 9 parts of sodium stearate and 3 parts of polyethylene glycol monomethyl ether are added to the auxiliary agent.

[0025] Example 5 The difference between this example and example 2 is that in this example, the sodium stearate added in the auxiliary is 6 parts, and the polyethylene glycol monomethyl ether added is 6 parts.

[0026] Example 6 The difference between this example and example 2 is that in this example, the sodium stearate added in the auxiliary is 8 parts, and the polyethylene glycol monomethyl ether added is 4 parts.

[0027] Example 7 The difference between this example and example 6 is that in this example, the nano-silicon is modified nano-silicon, and the preparation method comprises the following steps: dissolving 4 parts of N-phenyl palmitamide in 15 parts of dimethyl sulfoxide, then adding 8 parts of nano-silicon and uniformly dispersing, and drying to obtain modified nano-silicon.

[0028] Example 8 The difference between this example and example 7 is that in this example, the N-phenyl palmitamide added is 0.5 parts, and the nano-silicon added is 11.5 parts.

[0029] Example 9 The difference between this example and example 7 is that in this example, the N-phenyl palmitamide added is 2 parts, and the nano-silicon added is 10 parts.

[0030] Example 10 The difference between this example and example 7 is that in this example, the N-phenyl palmitamide added is 1 part, and the nano-silicon added is 11 parts.

[0031] Comparative Example 1 The difference between this comparative example and example 1 is that in this comparative example, no sodium stearate is added in the auxiliary, and 5 parts of polyethylene glycol monomethyl ether is added.

[0032] Comparative Example 2 The difference between this comparative example and example 1 is that in this comparative example, no polyethylene glycol monomethyl ether is added in the auxiliary, and 5 parts of sodium stearate is added.

[0033] Comparative Example 3 The difference between this comparative example and example 1 is that in this comparative example, neither polyethylene glycol monomethyl ether nor sodium stearate is added in the auxiliary.

[0034] Comparative Example 4 The difference between this comparative example and example 1 is that in this comparative example, no nano-silicon is added in the auxiliary.

[0035] Experimental Example 100.00 g of corn stalks from Anhui region, wherein the content of cellulose in the corn stalks ranges from 29% to 41%, the content of hemicellulose ranges from 21% to 27%, and the content of lignin ranges from 26% to 27%, and the average content of cellulose, hemicellulose and lignin is taken as the theoretical value, wherein the theoretical mass of cellulose is 35.00 g, the theoretical mass of hemicellulose is 24.00 g, and the theoretical mass of lignin is 26.50 g in 100.00 g of corn stalks; The cellulose, hemicellulose and lignin separated by the separation method of Examples 1-10 and Comparative Examples 1-4 are listed in Table 1, and the yield of cellulose, hemicellulose and lignin is calculated according to the following formula, respectively, cellulose yield (%) = actual separation mass / theoretical mass x 100%, hemicellulose yield (%) = actual separation mass / theoretical mass x 100%, and lignin yield (%) = actual separation mass / theoretical mass x 100%, and the results are rounded to two decimal places, and the results are shown in Table 1 below: Table 1 Actual separation mass and yield of cellulose, hemicellulose and lignin of Examples 1-10 and Comparative Examples 1-4

[0036] Compared with Comparative Examples 1-3, the yield of cellulose, hemicellulose and lignin of Example 1 is significantly improved, indicating that when sodium stearate and polyethylene glycol monomethyl ether are included in the auxiliary, the separation efficiency of cellulose, hemicellulose and lignin in biomass can be improved by the combination of the two. Compared with Comparative Example 4, the yield of cellulose, hemicellulose and lignin of Example 1 is significantly improved, indicating that when nano-silicon is introduced into the auxiliary, the separation efficiency of cellulose in biomass can be improved, and the separation efficiency of subsequent hemicellulose and lignin is also improved.

[0037] Compared with Examples 2 and 4, the yield of cellulose, hemicellulose and lignin of Examples 5-6 is improved, indicating that when the weight ratio of sodium stearate and polyethylene glycol monomethyl ether is 1-2:1, the separation efficiency of cellulose in biomass can be further improved, and the separation efficiency of subsequent lignin and hemicellulose is also further improved.

[0038] Compared with Example 6, the yield of cellulose, hemicellulose and lignin of Examples 7-10 is improved, indicating that the surface modification of nano-silicon with aromatic amide compounds further improves the separation efficiency of cellulose in biomass, and further improves the separation efficiency of lignin and hemicellulose in biomass. Compared with Examples 7-8, the yield of cellulose, hemicellulose and lignin of Examples 9-10 is improved, indicating that when the weight ratio of nano-silicon and aromatic amide compounds is 5-11:1, the separation efficiency of cellulose in biomass can be further improved, and the separation efficiency of lignin and hemicellulose in biomass is also further improved.

[0039] The above merely provides the preferred embodiment of the present application and not intended to limit the present application. Accordingly, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A method for separating cellulose, lignin and hemicellulose from biomass, characterized in that: The following steps are involved: S1. Mixing a biomass raw material with an additive, steaming, and separating to obtain a first liquid mixture and a first solid, wherein the first solid is washed and filtered to obtain cellulose; S2. separating the first liquid mixture to obtain a second liquid mixture and hemicellulose; S3, evaporating the second liquid mixture to obtain lignin; The auxiliary agent comprises the following components in parts by weight: 2-16 parts of nano silicon, 2-18 parts of sodium stearate, 2-6 parts of potassium carbonate, 3-8 parts of polyethylene glycol monomethyl ether, and 5000 parts of water.

2. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: The weight ratio of the sodium stearate to the polyethylene glycol monomethyl ether is 1-2:

1.

3. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: The nano-silicon is modified nano-silicon, and the modified nano-silicon is obtained by modifying nano-silicon with an aromatic amide compound.

4. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 3, characterized in that: The weight ratio of the nano-silicon to the aromatic amide compound is 5-11:

1.

5. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 3, characterized in that: The aromatic amide compound includes one or more of p-toluenesulfonic acid amide, N-phenylpalmitamide, and N-fluorobisbenzenesulfonamide.

6. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 3, characterized in that: The preparation method of the modified nano-silicon comprises the following steps: dissolving the aromatic amide compound in dimethyl sulfoxide, adding the nano-silicon and dispersing the mixture evenly, and drying the mixture to obtain the modified nano-silicon.

7. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: The biomass raw material is one or more of corn straw, wheat straw, rice straw, cotton straw, sugarcane straw, weeds, peanut shells, and walnut shells.

8. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: In terms of g / L, the mass volume ratio of the biomass raw material to the auxiliary agent is 1:10~30.

9. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: In step S2, the separation includes microfiltration separation and ultrafine separation, and the microfiltration separation and ultrafine separation each independently use a ceramic filter membrane; during the microfiltration separation, the pressure is 0.2~0.3MPa; during the ultrafine separation, the pressure is 0.8~1MPa.

10. The method for separating cellulose, lignin and hemicellulose from biomass according to claim 1, characterized in that: In step S1, during the steaming, the pressure is 3.5-5.5 MPa and the time is 6-8 min; during the filter pressing, the pressure is 6.5-9.5 MPa and the time is 10-20 min; in step S3, during the evaporation, the temperature is 105-115° C. and the time is 50-80 min.

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