Method for treating lignocellulose and use thereof

Abstract

This invention relates to the fields of bioengineering and chemical engineering, and discloses a method for treating lignocellulose and its application. The method includes: (1) spraying a catalyst solution onto a lignocellulose material layer; wherein, relative to 100 kg of lignocellulose, the spraying rate of the catalyst is 1-50 kg / h, and the amount of catalyst used is 0.5-32 kg; (2) after spraying, the material is squeezed and dehydrated to achieve a dry matter concentration of 20-60 wt%; (3) the material obtained in step (2) is sequentially subjected to cooking and enzymatic hydrolysis. The lignocellulose treatment method of this invention makes the catalyst and lignocellulose more uniformly mixed, avoiding the problem of "half-cooked" lignocellulose. At the same time, this method reduces the raw material loss rate and catalyst loss rate, resulting in a high conversion rate of lignocellulose.

Description

Technical Field

[0001] This invention relates to the fields of bioengineering and chemical engineering, and more specifically, to methods for processing and applying lignocellulose. Background Technology

[0002] Lignocellulose can be used for a variety of purposes, including processing into feed, fuel ethanol, biomass power generation, biogas, papermaking, and edible fungi.

[0003] Wetting methods can be categorized into three types: dipping, spreading, and immersion. Currently, most wetting of lignocellulosic materials employs the immersion method. However, this method easily introduces fine particles and impurities from materials with non-uniform particle sizes into the liquid, posing significant challenges to subsequent liquid processing, increasing liquid consumption and waste generation. The subsequent treatment of this waste also presents certain risks and difficulties. Furthermore, the loss of fine particles increases raw material costs. Moreover, using these wetting methods results in minimal moisture change after immersion and dehydration, limiting control methods and operational flexibility. Meanwhile, the wetting process of lignocellulose materials continuously increases the amount of impurities and fine particles in the liquid. The rising turbidity and dry matter content of the liquid directly affect the smoothness of the wetting operation. To ensure the normal operation of the wetting process, it is necessary to separate the impurities and fine particles from the liquid. This separation typically employs methods such as filtration and hydrocyclone separation. However, the recovery of fine particles is extremely difficult and uneconomical; in most cases, they end up mixing with impurities to form waste residue. The disposal of this waste residue also poses certain environmental risks. Ultimately, all of these problems lead to a significant reduction in the conversion rate of lignocellulose.

[0004] Therefore, there is an urgent need for a process that consumes less liquid and generates less waste residue, has a wide range of humidity control for materials, and contains fewer impurities and fine materials in the liquid. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of excessive retention of fine materials and impurities in liquids in existing technologies, which increase raw material and catalyst losses and have a small range of humidity control. This invention provides a method and application for processing lignocellulose, which reduces the retention of fine materials and impurities in liquids, reduces raw material and catalyst losses, and allows for flexible control of material humidity.

[0006] To achieve the above objectives, a first aspect of the present invention provides a method for treating lignocellulose, the method comprising:

[0007] (1) The catalyst solution is sprayed onto the lignocellulose material layer; wherein, relative to 100kg of lignocellulose, the spraying rate of the catalyst is 1-50kg / h, and the amount of catalyst is 0.5-32kg.

[0008] (2) After spraying, the material is squeezed and dehydrated so that the dry matter concentration of the material is 20-60 wt%.

[0009] (3) The material obtained in step (2) is steamed and enzymatically hydrolyzed in sequence.

[0010] The second aspect of the present invention provides the application of the method for treating lignocellulose described in the first aspect in the treatment of lignocellulose.

[0011] Through the above technical solution, the present invention can achieve at least the following beneficial effects:

[0012] (1) The method for treating lignocellulose in this invention makes the catalyst and lignocellulose more evenly mixed, avoiding the problem of "half-cooked" mixture.

[0013] (2) The method for treating lignocellulose in this invention requires less catalyst, thus reducing production costs;

[0014] (3) The method for treating lignocellulose in this invention results in low raw material loss rate and catalyst loss rate, and high lignocellulose conversion rate. Attached Figure Description

[0015] Figure 1 This is a process flow diagram of one embodiment of the present invention. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] The first aspect of this invention provides a method for treating lignocellulose, the method comprising:

[0018] (1) The catalyst solution is sprayed onto the lignocellulose material layer; wherein, relative to 100kg of lignocellulose, the spraying rate of the catalyst is 1-50kg / h, and the amount of catalyst is 0.5-32kg.

[0019] (2) After spraying, the material is squeezed and dehydrated so that the dry matter concentration of the material is 20-60 wt%.

[0020] (3) The material obtained in step (2) is steamed and enzymatically hydrolyzed in sequence.

[0021] The inventors of this invention discovered during their research that spraying the catalyst into the lignocellulose layer can better mix the two, greatly reducing the problem of the layer being "undercooked," thereby resulting in a high conversion rate of lignocellulose during subsequent cooking and enzymatic hydrolysis.

[0022] In this invention, preferably, the nozzle used for spraying can be a type of nozzle commonly used in the art, such as at least one of a spiral solid cone nozzle, a fan-shaped nozzle, and a spiral hollow cone nozzle.

[0023] In this invention, preferably, the spray temperature is 20-80℃, more preferably 40-60℃ (for example, it can be any two values ​​formed by 40℃, 42℃, 44℃, 46℃, 48℃, 50℃, 52℃, 54℃, 56℃, 58℃, and 60℃, or a value within that range).

[0024] In this invention, preferably, the concentration of the catalyst in the catalyst solution is 1-8 wt% (for example, it can be any two values ​​formed by 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, or values ​​within that range).

[0025] In this invention, preferably, the spraying rate of the catalyst relative to 100 kg of lignocellulose is 2-30 kg / h (for example, it can be any two values ​​from 2 kg / h, 4 kg / h, 6 kg / h, 8 kg / h, 10 kg / h, 12 kg / h, 14 kg / h, 16 kg / h, 18 kg / h, 20 kg / h, 22 kg / h, 24 kg / h, 26 kg / h, 28 kg / h, 30 kg / h, and any value within that range).

[0026] In this invention, preferably, the amount of catalyst used relative to 100 kg of lignocellulose is 1-30 kg (for example, it can be any two values ​​from 1 kg, 2 kg, 4 kg, 6 kg, 8 kg, 10 kg, 12 kg, 14 kg, 16 kg, 18 kg, 20 kg, 22 kg, 24 kg, 26 kg, 28 kg, 30 kg, or any value within that range).

[0027] It is understood that the above-mentioned catalyst spraying rate refers to the mass of catalyst sprayed in the catalyst solution per hour. For example, a spraying rate of 2 kg / h for sodium hydroxide catalyst means that 2 kg of sodium hydroxide catalyst is added per hour. That is, the catalyst spraying rate and the amount of catalyst used are based on the effective components of the catalyst.

[0028] In this invention, preferably, the catalyst is selected from at least one of ammonia, sodium hydroxide, sulfuric acid, sulfurous acid, phosphoric acid, ammonium sulfite, sodium sulfite, and sodium hypochlorite.

[0029] In this invention, preferably, the dry matter concentration of the material after extrusion and dehydration is 31-52 wt% (for example, it can be any two values ​​from 31 wt%, 35 wt%, 38 wt%, 40 wt%, 42 wt%, 44 wt%, 46 wt%, 48 wt%, 50 wt%, 52 wt%, and values ​​within that range).

[0030] In this invention, preferably, the pressure of the extrusion dehydration is not particularly limited, as long as the dry matter concentration of the extruded dehydrated material is 31-52 wt%. For example, relative to 100 kg of lignocellulose, the extrusion dehydration pressure is 500-1500 kPa, more preferably 700-900 kPa (for example, it can be any two values ​​from 700 kPa, 720 kPa, 740 kPa, 760 kPa, 780 kPa, 800 kPa, 820 kPa, 840 kPa, 860 kPa, 880 kPa, 900 kPa, and any value within that range).

[0031] In this invention, the lignocellulose layer and the catalyst are mixed by spraying, which not only makes the lignocellulose layer and the catalyst more uniformly mixed and reduces the problem of "half-cooked" mixture, but also reduces the amount of catalyst used, thereby reducing production costs. Moreover, compared with the soaking method, the method of this invention can achieve a low raw material loss rate and catalyst loss rate, and a high conversion rate of lignocellulose.

[0032] In this invention, preferably, the method further includes draining before squeezing and dehydration, wherein the time interval between spraying and draining is no longer than 3 minutes; and the time interval between draining and squeezing and dehydration is no longer than 3 minutes.

[0033] In this invention, the time interval between spraying and draining, as well as the time interval between draining and pressing dehydration, are reduced, which can speed up efficiency and increase the conversion of lignocellulose in the same amount of time.

[0034] In this invention, preferably, the method further includes: recovering the liquid phase from the draining and / or squeezing dehydration process and reusing it in step (1) for preparing the catalyst solution.

[0035] In this invention, preferably, the filter screen pore size for recovering the squeezed dehydrated liquid phase is 2-15 mm, more preferably 6-10 mm (for example, it can be any two values ​​formed by 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, or any value within that range).

[0036] In this invention, preferably, the draining method involves conveying the material after spraying through a conveying device with a filter screen having a pore size of 0.5-6mm. The pore size of the filter screen is preferably 2-4mm (for example, it can be any two values ​​formed by 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, and 4mm, or any value within that range).

[0037] In this invention, preferably, the draining is performed until the dry matter concentration is 5-20 wt%, more preferably 10-15 wt% (for example, it can be any two values ​​from 10 wt%, 10.5 wt%, 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, 15 wt%, and values ​​within that range).

[0038] In this invention, preferably, the cooking pressure is 0.3-2 MPa, more preferably 0.6-1.6 MPa (for example, it can be any two values ​​formed by 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, and 1.6 MPa, or values ​​within that range); the cooking time is 0.1-1 h, preferably 0.2-0.8 h (for example, it can be 0.2 h, 0.3 h, 0.4 h, 0.5 h, 0.6 h, and 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1 MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, and 1.6 MPa, or values ​​within that range); The cooking temperature is 134-212℃, preferably 155-205℃ (for example, it can be any two values ​​from 155℃, 157℃, 160℃, 162℃, 164℃, 168℃, 170℃, 172℃, 174℃, 176℃, 178℃, 180℃, 182℃, 184℃, 186℃, 188℃, 190℃, 192℃, 194℃, 196℃, 198℃, 200℃, 205℃, forming a range or value within that range).

[0039] In this invention, preferably, the enzymatic hydrolysis conditions include: an enzymatic hydrolysis temperature of 45-65℃, more preferably 50-55℃ (for example, it can be any two values ​​from 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, or any value within that range); and an enzymatic hydrolysis time of 48-96h, more preferably 56-72h (for example, it can be any two values ​​from 56h, 58h, 60h, 62h, 64h, 66h, 68h, 70h, 72h, or any value within that range).

[0040] In this invention, preferably, the enzyme used for enzymatic hydrolysis is a complex enzyme of cellulase and hemicellulase.

[0041] In this invention, preferably, the mass ratio of cellulase to hemicellulase in the composite enzyme is 1:0.1-0.3.

[0042] In this invention, preferably, the total amount of enzyme used is between 1.12 million BHU and 4.2 million BHU. It is understood that "BHU" refers to a unit of enzyme dosage.

[0043] In this invention, preferably, the lignocellulose is at least one of corn stalks, wheat stalks, reeds, bamboo shoots, fungus grass, cotton stalks, rapeseed stalks, sorghum stalks, sugarcane bagasse, hemp stalks, willow branch millet, and rice stalks.

[0044] In a preferred embodiment of the present invention, the specific process flow can be referred to Figure 1 The process flow diagram.

[0045] The second aspect of the present invention provides the application of the method for treating lignocellulose described in the first aspect in the treatment of lignocellulose, preferably at least one of corn stalks, wheat stalks, reeds, rush, bulrush, cotton stalks, rapeseed stalks, sorghum stalks, sugarcane bagasse, hemp stalks, willow sorghum, and rice stalks.

[0046] The present invention will be described in detail below through embodiments. In the following embodiments and comparative examples, according to... Figure 1 The process shown is followed; the crude enzyme raw material (unconcentrated complex enzyme product with a mass ratio of cellulase and hemicellulase of 1:0.2) is a commercially available product from Novozymes under the brand name CellicSD1.0;

[0047] The lignocellulosic material (corn stalks) contains 40 wt% cellulose, 20 wt% hemicellulose, and 30 wt% lignin.

[0048]

[0049] Among them, the moisture content of the filter residue refers to the moisture content in the dry matter after mechanical extrusion;

[0050] Lignocellulose conversion rate = glucose (wt%) / dry matter of ingredients (%) / cellulose content of raw materials (%); where dry matter of ingredients refers to the proportion of absolutely dry matter in the fluid dynamic enzymatic hydrolysate prepared by mixing solid gas explosion material and water in a certain proportion.

[0051] Among them, the amount of oven-dry raw material in the filtrate refers to the amount of oven-dry material lost after spraying or soaking.

[0052] The concentration of acetic acid in the enzymatic hydrolysate was determined by liquid chromatography using an Agilent or Shimadzu liquid chromatograph, and sigma-grade acetic acid was used as the standard.

[0053] Examples 1-3

[0054] (1) Spray mixing: 100kg of lignocellulose material (corn stalks) is conveyed into the spray mixing equipment. During the spraying process, excess catalyst liquid is generated. After passing through the filter screen at the bottom of the equipment, it is collected by the filtrate outlet and discharged to the separation equipment. The separated liquid phase is reused to prepare catalyst solution.

[0055] (2) Humidity control: The material produced in the spray mixing stage enters the dewatering stage, where it is transported by the dewatering equipment and passes through the filter screen at the bottom of the equipment to remove excess catalyst liquid. The collected liquid is then discharged to the separation equipment, and the separated liquid phase is reused to prepare catalyst solution. After dewatering, the material enters the mechanical extrusion stage, which allows the catalyst liquid on the surface of the material to penetrate into the internal fiber structure of the material, further ensuring the uniformity of catalyst dispersion in the material. During this process, the material is shaped, which increases the bulk density and final dry matter content. The extruded liquid is collected in the separation equipment, and the separated liquid phase is reused to prepare catalyst solution.

[0056] (4) The cooking material is fed into a sealed cooking container and released after a period of time to obtain solid cellulose material.

[0057] (5) Enzymatic hydrolysis: Cellulose sugars are ultimately produced under the action of enzymes. Specific parameters are shown in Table 1. Raw material loss rate, catalyst loss rate, and lignocellulose conversion rate are shown in Table 2.

[0058] Table 1

[0059]

[0060]

[0061] The catalyst concentration in Table 1 refers to the concentration of the catalyst solution, and the catalyst dosage refers to the dosage of the effective components of the catalyst; PS series nozzles, P series nozzles and A / B type nozzles refer to spiral solid cone nozzles, fan-shaped nozzles and spiral hollow cone nozzles, respectively.

[0062] Example 4

[0063] The method of Example 3 was used to process lignocellulose, except that the filter screen for recovering excess liquid in step (1) of the mixing and spraying process was 6 mm in diameter.

[0064] Example 5

[0065] The lignocellulose was treated according to the method of Example 3, except that the filter screen pore size of the recovered filtrate was 15 mm during the humidity adjustment process in step (2).

[0066] Example 6

[0067] The method of Example 3 was used to treat lignocellulose, except that the catalyst spraying rate was 50 kg / h during the mixing and spraying process in step (1).

[0068] Comparative Example 1

[0069] 100 kg of lignocellulose material was soaked in a solution containing a catalyst for 1 hour; the catalyst solution was composed of 8 wt% phosphoric acid and the amount of catalyst used was 32 kg.

[0070] Comparative Example 2

[0071] The method of Example 3 was used to treat lignocellulose, except that the amount of catalyst solution used remained unchanged during the spraying and mixing process in step (1), and the spraying rate was 60 kg / h.

[0072] Comparative Example 3

[0073] The method of Example 3 was used to treat lignocellulose, except that step (1) of spraying and mixing was replaced with wetting. The lignocellulose was passed through a container containing a catalyst solution to achieve the purpose of wetting. The specific method is as follows:

[0074] 100 kg of lignocellulose is added to a container, and 50 kg of the active catalyst component (phosphoric acid, concentration 10 wt%) is added. The lignocellulose is soaked for 2 hours. The container has a catalyst and material separation device at the end. The separated catalyst is reused. The total amount of catalyst used is 40 kg. The time interval between the soaking time and the draining time is 2 minutes.

[0075] Table 2

[0076]

[0077]

[0078] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for treating lignocellulose, characterized in that, The method includes: (1) The catalyst solution is sprayed onto the lignocellulose material layer; wherein, relative to 100kg of lignocellulose, the spraying rate of the catalyst is 1-50kg / h, and the amount of catalyst is 0.5-32kg. (2) After spraying, the material is squeezed and dehydrated so that the dry matter concentration of the material is 20-60 wt%. (3) The material obtained in step (2) is steamed and enzymatically hydrolyzed in sequence.

2. The method according to claim 1, wherein, The nozzles used for spraying are selected from at least one of spiral solid cone nozzles, fan nozzles, and spiral hollow cone nozzles; And / or, the temperature of the spray is 20-80°C, preferably 40-60°C; And / or, the concentration of the catalyst in the catalyst solution is 1-8 wt%.

3. The method according to claim 1 or 2, wherein, The spraying rate of the catalyst is 2-30 kg / h relative to 100 kg of lignocellulose; And / or, relative to 100 kg of lignocellulose, the amount of catalyst used is 1-30 kg; And / or, the catalyst is selected from at least one of ammonia, sodium hydroxide, sulfuric acid, sulfurous acid, phosphoric acid, ammonium sulfite, sodium sulfite, and sodium hypochlorite; And / or, the dry matter concentration of the extruded and dehydrated material is 31-52 wt%.

4. The method according to claim 1, wherein, The method further includes draining water before squeezing and dehydration, wherein the time interval between spraying and draining is no longer than 3 minutes; and the time interval between draining and squeezing and dehydration is no longer than 3 minutes.

5. The method according to claim 4, wherein, The method further includes: recovering the liquid phase from the draining and / or squeezing dehydration process and reusing it in step (1) for preparing the catalyst solution; And / or, the filter screen pore size for recovering the extruded dehydrated liquid phase is 2-15 mm, preferably 6-10 mm; And / or, relative to 100 kg of lignocellulose, the pressure for extrusion dehydration is 500-1500 kPa, preferably 700-900 kPa.

6. The method according to claim 5, wherein, The draining method involves conveying the material after spraying through a conveying device with a filter screen having a pore size of 0.5-6mm, preferably 2-4mm. And / or, the draining continues until the dry matter concentration is 5-20 wt%, preferably 10-15 wt%.

7. The method according to claim 1, wherein, The cooking pressure is 0.3-2 MPa, preferably 0.6-1.6 MPa; the cooking time is 0.1-1 h, preferably 0.2-0.8 h; and the cooking temperature is 134-212℃, preferably 155-205℃.

8. The method according to claim 1, wherein, The conditions for enzymatic hydrolysis include: an enzymatic hydrolysis temperature of 45-65℃, preferably 50-55℃; and an enzymatic hydrolysis time of 48-96h, preferably 56-72h. And / or, the enzyme used in the enzymatic hydrolysis is a complex enzyme of cellulase and hemicellulase; Preferably, in the composite enzyme, the mass ratio of cellulase to hemicellulase is 1:0.1-0.3; Preferably, the total amount of the enzyme used is between 1.12 million BHU and 4.2 million BHU.

9. The method according to any one of claims 1-8, wherein, The lignocellulose is at least one of corn stalks, wheat stalks, reeds, alfalfa, bulrush, cotton stalks, rapeseed stalks, sorghum stalks, sugarcane bagasse, hemp stalks, willow sorghum, and rice stalks.

10. The method for treating lignocellulose according to any one of claims 1-9 is used in the treatment of corn lignocellulose, preferably in at least one of corn stalks, wheat stalks, reeds, rush, bulrush, cotton stalks, rapeseed stalks, sorghum stalks, sugarcane bagasse, hemp stalks, willow sorghum, and rice stalks.

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