A large-scale size-reduction method for improving the reaction performance of biomass raw materials

Abstract

The application discloses a large-scale size-reducing method for improving reaction performance of biomass raw materials, which comprises the following steps: steam treatment of biomass raw materials after water washing and soaking to obtain steamed materials; extrusion treatment of the steamed materials by a double-screw extrusion impregnation machine to obtain extruded materials, which are in the form of coarse wood filaments; water is added to the extruded materials to obtain materials with a solid content of 15-35%, which are ground by a disc mill under normal pressure; during the grinding process, fiber bundles in the biomass raw materials are microfilamentized to obtain biomass materials with improved reaction performance. By the combined use of the double-screw extrusion impregnation machine and the disc mill, the present application can cut fibers, reduce the particle size of the biomass raw materials, realize dissociation and floc separation of the fibers, expose more reaction sites, and improve the specific surface area and reaction performance of the biomass raw materials. In addition, the double-screw extrusion impregnation machine and the disc mill used in the present application are both suitable for large-scale and industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biomass refining, and particularly relates to a large-scale size reduction method for improving the reaction performance of biomass raw materials. BACKGROUND

[0002] Developing clean and renewable energy has become one of the key tasks of China's sustainable development strategy. Wood fiber raw materials are widely concerned due to their advantages such as abundant yield, renewability, sustainability, biodegradability and carbon neutrality. However, cellulose, hemicellulose and lignin in wood fiber raw materials are connected to each other through chemical bonds or other special forms in the cell wall to form a complex and dense network structure, which hinders their economic and efficient conversion and utilization. The preparation of fuels and chemicals requires full contact of chemicals, enzymes and microorganisms with fiber raw material substrates, and therefore, effective pretreatment is needed before the biological conversion process to improve the accessibility of fiber raw materials.

[0003] In recent years, researchers have studied various pretreatment methods to improve the accessibility of fiber raw materials, such as chemical (alkali, acid, oxidizing agent and organic solvent), physical-chemical (steam explosion, ultrasonic + chemical combination), biological or combination of these pretreatment technologies. These pretreatment technologies can effectively improve the utilization and conversion rate of fiber raw materials. In order to achieve the efficiency of the pretreatment technology, wood powder with a particle size of less than 62 um (20 mesh) is mostly obtained by pulverizing to achieve the purpose of reducing particle size and increasing the specific surface area of biomass.

[0004] Existing mechanical treatment technologies mostly use a pulverizer to pulverize to obtain a higher specific surface area to improve the reaction performance of the material, but the pulverizing technology mostly only performs simple cutting, the pulverizing effect is uneven, the pulverizing efficiency is low, and the reaction performance of the biomass raw material after cutting is not considered. CN113647253A discloses a biomass raw material pulverizing device, which drives the first and second pulverizing assemblies by setting a pulverizing structure, improves the pulverizing effect of the device, and enhances the pulverizing efficiency of the device by vibrating the pulverizing box during the driving of the second pulverizing assembly by the transmission assembly. However, the obtained raw material is still a granular raw material obtained by shearing force, and does not have microfibrilization or the like to increase the contact area of the fiber and the chemical liquid.

[0005] Some studies use a ball mill to reduce the particle size of biomass, which has good pulverizing effect, small and uniform powder particle size and good reaction performance, but has long ball milling time, low efficiency, high energy consumption and cannot be produced on a large scale. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a large-scale size reduction method for improving the reaction performance of biomass raw materials, which can reduce the particle size to increase the specific surface area, thereby improving the reactivity of the biomass raw materials, and can also disperse the fibers to make the fibers into filaments, thereby increasing the contact area between the liquor and the biomass, achieving the purpose of improving the reaction performance of the biomass raw materials, and improving the utilization efficiency of the subsequent biomass raw materials.

[0007] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0008] A large-scale size reduction method for improving the reaction performance of biomass raw materials, comprising the following steps:

[0009] Selecting eucalyptus wood chips, poplar wood chips or bamboo chips as the biomass raw materials, after being washed with water, soaking for 2-36h, removing excess water by filtration, then steam treatment at 105℃ for 10-15min to obtain steam material; the steam material is subjected to extrusion treatment by a twin-screw extrusion impregnator (TSPI) to obtain extruded material, which is in the form of coarse wood filaments; water is added to the extruded material to obtain a material with a solid content of 15-35%, and the material is subjected to grinding by a disc grinder under normal pressure, the grinding energy consumption of the disc grinder is 1000-2500kwh / t, and the fiber bundles in the biomass raw materials are microfilamentized during the grinding process, thereby obtaining biomass material with improved reaction performance.

[0010] The twin-screw extrusion impregnator used in the present application has two screws rotating in opposite directions, and the distance between the teeth on the screws is different, forming a repeated "extrusion-loosening" effect, and the wood chips in the interior of the screw are subjected to the combined action of extrusion force, friction force and shear force to form filamentous extruded material.

[0011] The grinding area in the disc grinder used in the present application is divided into three regions according to the tooth shape: grinding zone, grinding zone and fine grinding zone, when the material enters the disc grinder, the fibers are captured by the edge of the teeth, and then subjected to the action force between the tooth surfaces, and the friction, rubbing and crushing forces during the process of leaving the edge of the teeth, the fiber length is reduced, the fiber bundles are rubbed open and microfilamentized at the same time, thereby increasing the specific surface area and improving the reaction performance.

[0012] The present application has the following advantages:

[0013] The existing mechanical pretreatment technology in the biomass refining process is mainly in the form of cutting and crushing, and the fiber is in the form of bundle structure, which hinders the penetration of the liquid medicine and the reaction; the ball mill can obtain more delicate and larger specific surface area biomass raw materials, but the processing time is long, the energy consumption is large, the processing amount is small, and continuous production cannot be realized; the present application realizes the fine grinding, cutting and splitting of the fiber raw material by using the double screw extrusion impregnation machine with "extrusion-loosening" structure and the disc mill, and more reaction sites are exposed, the specific surface area is increased, and the liquid absorption capacity of the biomass raw material is improved, so that the reaction performance of the biomass raw material is improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The appearance of the material obtained by the method in the present application is compared with the appearance of the material obtained by the conventional mechanical crushing. DETAILED DESCRIPTION

[0015] The present application will be further described below in conjunction with examples, so that those skilled in the art can better understand the present application and implement it, but the examples are not limiting to the present application.

[0016] In addition, in the preparation process in the following examples, if not specifically stated, it is a conventional means in the existing art in the art, therefore, it will not be described in detail.

[0017] Example 1

[0018] The material obtained by the conventional mechanical crushing is compared with the material obtained by the method in the present application, and the particle size and yield of each material are shown in Table 1; the appearance of each material is shown in Figure 1 .

[0019] Table 1 Particle size and yield analysis results of the material obtained by different mechanical treatment methods

[0020]

[0021] (Note: "blank" is not measured, "+" means that it cannot pass through the mesh size, and "-" means that it can pass through the mesh size)

[0022] From Table 1, it can be seen that the yield of the material obtained by the method of TSP+disc mill combination in the present application is significantly higher than that of the conventional mechanical crushing method. From Figure 1 it can be seen that many small spurs and the like can be observed in the material obtained by the method in the present application, which is the result of the fiber bundle being rubbed open and being microfilamentized at the same time.

[0023] Example 2

[0024] The eucalyptus wood chips were soaked for 2 hours after washing with deionized water, and the wood chips were drained after being taken out. The wood chips were steamed at 105°C for 10 minutes, and were extruded into a coarse wood fiber state using a double screw extrusion digester with "extrusion-loosening" effect. The material after extrusion was adjusted to 15% concentration using deionized water, and was ground using a disc grinder at normal pressure. The disc gap was controlled, and the disc energy input was 1050 kwh / t, to obtain material P1.

[0025] The material P1 obtained in Example 2 and eucalyptus wood powder with a size of 80 mesh obtained by a conventional crusher were respectively subjected to delignification treatment and enzyme hydrolysis experiments according to the following methods to detect the reaction performance.

[0026] Delignification treatment: the content of each medicine in the delignification solution was as follows: NaOH (19.8 wt%), H2O2 (27 wt%), Na2SiO3 (2 wt%), diethyl triamine pentaacetic acid (DTPA) (0.5 wt%), ethanol (15 wt%), and the reaction concentration was 25%. The solution was poured into a beaker and mixed (all the medicine dosages were based on the absolute dry raw material). The solution was quickly mixed with the material, and was then sealed in a pressure-resistant glass flask. The flask was placed in a preheated constant temperature water bath at 90°C, and was kept for 120 minutes for delignification treatment. After the delignification treatment was completed, the solid component and the filtrate were separated using a 400 mesh filter cloth, and the solid component was washed with distilled water until it was neutral. The solid after delignification was subjected to enzyme hydrolysis experiments.

[0027] The test results of the specific surface area, liquid absorption capacity and reaction performance (lignin removal rate, enzyme hydrolysis yield) of the material P1 and the eucalyptus wood powder with a size of 80 mesh are shown in Table 2. As can be seen from Table 2, the combined mechanical treatment method using the double screw extrusion digester and the disc grinder of the present application can improve the specific surface area and the liquid absorption capacity of the eucalyptus wood, and further improve the reaction performance.

[0028] Table 2

[0029]

[0030] Example 3

[0031] The poplar wood chips were soaked for 36 hours after washing with deionized water, and the wood chips were drained after being taken out. The wood chips were steamed at 105°C for 30 minutes, and were extruded into a coarse wood fiber state using a double screw extrusion digester with "extrusion-loosening" effect. The material after extrusion was adjusted to 25% concentration using deionized water, and was ground using a disc grinder at normal pressure. The disc gap was controlled, and the disc energy input was 1180 kwh / t, to obtain material P2.

[0032] The material P2 obtained in Example 3 and poplar powder with a size of 80 mesh obtained by a conventional pulverizer were respectively subjected to delignification treatment and enzyme hydrolysis experiment in the following methods to detect the reaction performance.

[0033] Delignification treatment: the content of each medicine in the delignification solution was as follows: NaOH (15 wt%), H2O2 (13 wt%), Na2SiO3 (2 wt%), diethyltriamine pentaacetic acid (DTPA) (0.5 wt%), the reaction concentration was 20%, and the solution was poured into a beaker for mixing (all the medicine dosages were based on the absolute dry raw material), and then the solution was quickly mixed with the material and then sealed in a pressure-resistant glass flask, and the flask was placed in a preheated constant temperature water bath at 90°C for 120 min for delignification treatment. After the delignification treatment was completed, the solid component and the filtrate were separated by using a 400 mesh filter cloth, and the solid component was washed with distilled water until it was neutral. The solid after delignification was subjected to enzyme hydrolysis experiment.

[0034] The specific surface area, liquid absorption capacity and reaction performance (lignin removal rate and enzyme hydrolysis yield) of the material P2 and the poplar powder with a size of 80 mesh were tested, and the results are shown in Table 3. As can be seen from Table 3, the combined mechanical treatment method of the double screw extrusion impregnator and the disc mill can improve the specific surface area and the liquid absorption capacity of the poplar, and thus improve the reaction performance.

[0035] Table 3

[0036]

[0037] Example 4

[0038] The bamboo chips were washed with deionized water to remove impurities, and then soaked in water at room temperature for 24 h. After the bamboo chips were taken out and drained, they were steamed at 105°C for 15 min. The double screw extrusion impregnator with "extrusion-loosening" effect was used to extrude the bamboo chips into a rough bamboo silk state. After extrusion, the material was adjusted to a concentration of 20% with deionized water, and then milled by a disc mill under normal pressure. The mill disc energy input was controlled at 2080 kwh / t, and the material P3 was obtained.

[0039] The material P3 obtained in Example 4 and the bamboo powder with a size of 80 mesh obtained by a conventional pulverizer were respectively subjected to delignification treatment and enzyme hydrolysis experiment in the following methods to detect the reaction performance.

[0040] Delignification treatment: the content of each medicine in the delignification solution is: NaOH (22wt%), H2O2 (30wt%), Na2SiO3 (4wt%), diethyl triamine pentaacetic acid (DTPA) (1wt%), the reaction concentration is 10%, pour into a beaker and mix (all the medicine dosage is based on the absolute dry raw material), mix quickly with the material, then seal in a glass flask, put the flask into a preheated to 90°C constant temperature water bath, keep warm for 60min to carry out delignification treatment. After delignification treatment, separate the solid component and the filtrate with 400 mesh filter cloth, and wash the solid component with distilled water until it is neutral, then carry out enzyme hydrolysis experiment on the delignified solid.

[0041] The specific surface area, liquid absorption capacity and reaction performance (lignin removal rate, enzyme hydrolysis yield) of material P3 and bamboo powder with a mesh size of 80 are tested, and the test results are shown in Table 4. As can be seen from Table 4, the combined mechanical treatment method of the double screw extrusion impregnation machine and the disc mill of the present application can improve the specific surface area and liquid absorption capacity of the bamboo chips, and thus improve the reaction performance thereof.

[0042] Table 4

[0043]

[0044] Obviously, the described embodiments are part of the embodiments of the present application, but not all. 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.

Claims

1. A method for improving the reaction performance of a biomass feedstock by size reduction on a large scale, characterized by: The method comprises the following steps: The biomass raw material is subjected to steaming treatment after water washing and soaking to obtain steamed material; the steamed material is subjected to extrusion treatment by a double-screw extrusion impregnator to obtain extruded material; water is added to the extruded material to obtain material with a solid content of 15-35%, and the material is subjected to beating-up by a disc refiner under normal pressure, during which the fiber bundles in the biomass raw material are microfibrillated to obtain biomass material with improved reaction performance.

2. The method for improving the reaction performance of biomass raw materials according to claim 1, characterized in that: The biomass raw material is eucalyptus wood chips, poplar wood chips or bamboo chips.

3. The method of claim 1, wherein the biomass feedstock is a lignocellulosic material. The soaking time is 2-36 h.

4. The method of claim 1, wherein the biomass feedstock is a lignocellulosic material. The steaming treatment temperature is 105℃.

5. The method of claim 4, wherein the biomass feedstock is a lignocellulosic biomass feedstock. The steaming treatment time is 10-15 min.

6. The method according to any one of claims 1 to 5, wherein the method is characterized by: The beating-up energy consumption of the disc refiner is 1000-2500 kwh / t.

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