Method for rapidly extracting hemicellulose component of sugarcane tail leaves through dry pretreatment
Through dry pretreatment technology, the use of multi-element decrystallization depolymerization agents to interact with sugarcane tail leaves solves the problems of high energy consumption and large amounts of wastewater in the existing sugarcane tail leaf pretreatment methods, and achieves high-efficiency and low-consumption hemicellulose Vitamin extraction, suitable for industrial applications.
Patent Information
- Application Number
- CN202410598344.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-14
- Publication Date
- 2025-01-21
AI Technical Summary
The existing pretreatment methods for sugarcane tail leaves have problems such as high energy consumption, large wastewater volume, and many by-products, resulting in high costs and low resource utilization efficiency.
Using dry pretreatment technology, a multi-element decrystallization depolymerizing agent (MAA) is used to interact with sugarcane tail leaves at a certain temperature to destroy the intermolecular forces of cell wall components, especially the connecting bonds with hemicellulose, and then The hemicellulose component is dissolved with warm water, and the retention rate of cellulose and lignin in the solid material is high.
A semi -cellulose extraction of high -solid content, low water consumption, and high income, and the process is simple and simple, suitable for industrialization promotion, reducing energy consumption and wastewater production.
Smart Images
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Figure HSA0000297964230000012
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of biorefining, and in particular relates to a method for quickly extracting hemicellulose components from sugarcane tail leaves through dry pretreatment. Background Art
[0002] Sugarcane tail leaves, also known as sugarcane tail tips, are the collective name for the tenderest nodes and green leaves on the top of sugarcane, accounting for about 15% to 20% of the biomass of sugarcane. They are the discarded part after sugarcane harvesting and are one of the important crop by-products in my country. my country, Brazil and India are the world's major sugarcane planting countries and edible sugar producers. According to data from the Ministry of Agriculture and Rural Affairs, in 2022 / 2023, the sugarcane planting area will be 1,163,000 hectares, and the sugarcane yield will be about 64.8 tons / hectare, of which the biomass of sugarcane tail leaves will be about 1.5 million tons. Sugarcane tail leaves have the potential to be used as industrial raw materials because they are rich in cellulose, hemicellulose and lignin components, and can produce high-value products in biorefining. However, compared with other biomass resources such as sugarcane bagasse and corn straw that have been widely studied, there are fewer studies on the high value of sugarcane tail leaves.
[0003] Pretreatment is the first key step in crop straw biorefining technology. Its main function is to effectively depolymerize the solid supramolecular structure of the cell wall of straw tissue, realize the separation and recovery of cellulose, hemicellulose and lignin, and lay the foundation for the utilization of crop straw biomass resources. Like other biomass pretreatment methods, the current pretreatment methods for sugarcane tail leaves also include physical methods, chemical methods, biological methods and combined methods, among which acid, alkali, steam explosion, ammonia fiber explosion and high-temperature liquid water pretreatment are the mainstream. In steam explosion, ammonia fiber explosion and other methods, the solid content of the material in the pretreatment system is 40% to 70%, but the energy consumption is very high, the performance requirements of the instrument and equipment are strict, and the maintenance cost is high. Usually, the raw materials are soaked in liquid (acid, alkali, ionic liquid, organic solvent or water, etc.) for pretreatment, but the solid content is relatively low, 5% to 14%, and there are high energy consumption, large amount of wastewater, and many by-products, which bring about the problem of low cost and subsequent utilization efficiency of the product.
[0004] Many studies have tried to increase the solid content in pretreatment and reduce the amount of liquid used to overcome the above problems. Among them, the research group of Professor Bao Jie of East China University of Science and Technology proposed the "dry acid pretreatment technology", which adds straw materials and dilute sulfuric acid in a solid-liquid ratio of 2:1 (solid content of 66.67%) to a spiral ribbon stirring reactor, and then passes steam for heating treatment. After pretreatment, the solid content of the straw material is maintained at about 50% (w / w), no wastewater is generated, and the steam energy consumption is effectively reduced. The use of dilute sulfuric acid reduces the corrosion of the equipment to a "quite corrosion-resistant" level. However, the sulfuric acid catalyst used in this method forms sulfate after neutralization, which not only reduces the subsequent combustion efficiency of lignin residue, but also has the risk of sulfur oxide spillover.
[0005] After a certain pretreatment of biomass raw materials, the connecting bonds and molecular forces between cellulose, hemicellulose and lignin are destroyed, and certain strategies can be adopted to separate and recycle the components. Compared with cellulose and lignin, hemicellulose is easier to depolymerize and degrade under heating or acidic conditions. Therefore, the hemicellulose-first lignocellulose separation technology can maximize the separation and recovery of all lignocellulose components and promote the maximization of resource utilization efficiency.
[0006] Therefore, it is of great significance to develop clean and low-cost pretreatment methods and processes to quickly extract hemicellulose components from sugarcane tail leaves. Summary of the invention
[0007] The object of the present invention is to provide a method for rapid extraction of hemicellulose components from sugarcane tail leaves by dry pretreatment, so as to achieve rapid extraction of hemicellulose components from sugarcane tail leaves, and lay a foundation for the subsequent utilization of hemicellulose components and the extraction and utilization of residual cellulose components. This method uses the "multi-crystallization depolymerization agent" (hereinafter represented by MAA) designed by this laboratory to interact with sugarcane tail leaves under a certain temperature, destroy the intermolecular forces of cell wall components, and especially break the connecting bonds with hemicellulose. After the pretreatment, the hemicellulose components can be dissolved with only a small amount of warm water, and the retention rate of cellulose and lignin in the solids is high, which is conducive to further component separation and comprehensive utilization. MAA is a solution containing three components a, b, and c. After pretreatment, it remains in the free part of the material, can be soluble in water or adjusted to pH neutralization, and is non-toxic and harmless. The method of the present invention has the advantages of high solid content, low water consumption, high yield, and clean and simple process, and is suitable for industrial promotion.
[0008] To achieve the above object, the present invention provides the following solutions:
[0009] A method for rapidly extracting hemicellulose components from sugarcane tail leaves by dry pretreatment, comprising the following steps:
[0010] (1) Prepare MAA by mixing a, b and c in a certain volume ratio.
[0011] (2) Sugarcane tail leaves and the MAA prepared in step (1) are placed in a hydrothermal reactor at a certain solid-liquid ratio and reacted at a set temperature for a suitable time.
[0012] (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
[0013] Preferably, the volume ratio of a, b and c of the MAA in step (1) is 340:400:1 to 340:50:1.
[0014] Preferably, the sugarcane tail leaves in step (2) are dried, crushed and sieved materials with a water content of about 8 to 20%.
[0015] Preferably, the solid-to-liquid ratio of the sugarcane tail leaves to MAA in step (2) is 1:2 to 5:1 (w / v).
[0016] Preferably, the reaction temperature in step (2) is 115-140°C.
[0017] Preferably, the reaction time in step (2) is 2 to 5 hours.
[0018] Particularly, after the pretreatment in step (3), the solid content of the sugarcane tail leaves is between 8% and 60% and there is no free waste liquid.
[0019] The present invention has the following beneficial effects: 1. The present invention is a dry pretreatment technology, and no free wastewater is generated after pretreatment. Compared with the currently commonly used solvent method (acid, alkali, ionic liquid, etc.), it has the advantages of being non-toxic and environmentally friendly. Compared with the hydrothermal method, it has the advantages of being highly efficient and energy-saving. 2. The present invention adopts a hemicellulose component priority separation strategy, has a higher retention rate for cellulose and lignin, and lays the material foundation for the separation and recovery of all components of lignocellulose. 3. The present invention has a simple process and is easy to implement. It can be applied to industrial production and has good economic and ecological benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a scanning electron microscope comparison of sugarcane tail leaves before and after the pretreatment of the present invention.
[0021] Figure 2 This is the infrared absorption spectrum of sugarcane tail leaves before and after the pretreatment of the present invention. DETAILED DESCRIPTION
[0022] The present invention is further described below with reference to specific examples, which are not intended to limit the present invention. The present invention adopts conventional reagents, methods and equipment in the art, unless otherwise specified.
[0023] After being washed, dried, crushed and sieved, the sugarcane tail leaves are pretreated using the technology of the present invention. The changes in the solid hemicellulose, cellulose and lignin contents are determined by the Van Soest method, and the extraction rate or retention rate is calculated based on the corresponding component contents of the raw materials. The total sugar and reducing sugar mass in the washing liquid are measured by the phenol-sulfuric acid method and the 3,5-dinitrosalicylic acid method, respectively, and the total sugar and reducing sugar extraction rates are calculated based on the dry matter mass of the raw materials, and the ratio of the two is the average degree of polymerization.
[0024] Example 1
[0025] A method for rapidly extracting hemicellulose components from sugarcane tail leaves by dry pretreatment, comprising the following steps:
[0026] (1) MAA was prepared by mixing a, b and c in a volume ratio of 340:50:1.
[0027] (2) Sugarcane tail leaves and the MAA prepared in step (1) were placed in a hydrothermal reactor at a solid-liquid ratio of 5:1 and reacted at 120° C. for 3 h.
[0028] (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
[0029] The results showed that the hemicellulose extraction rate was 53.05%, the cellulose and lignin retention rates were 90.42% and 89.37% respectively, the total sugar and reducing sugar extraction rates were 21.68% and 4.68% respectively, and the average degree of polymerization was 4.63.
[0030] Example 2
[0031] A method for rapidly extracting hemicellulose components from sugarcane tail leaves by dry pretreatment, comprising the following steps:
[0032] (1) MAA was prepared by mixing a, b and c in a volume ratio of 340:400:1.
[0033] (2) Sugarcane tail leaves and the MAA prepared in step (1) were placed in a hydrothermal reactor at a solid-liquid ratio of 5:1 and reacted at 120° C. for 2 h.
[0034] (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
[0035] The results showed that the hemicellulose extraction rate was 60.59%, the cellulose and lignin retention rates were 98.53% and 88.01% respectively, the total sugar and reducing sugar extraction rates were 23.45% and 9.55% respectively, and the average degree of polymerization was 2.46.
[0036] Example 3
[0037] A method for rapidly extracting hemicellulose components from sugarcane tail leaves by dry pretreatment, comprising the following steps:
[0038] (1) MAA was prepared by mixing a, b and c in a volume ratio of 340:400:1.
[0039] (2) Sugarcane tail leaves and the MAA prepared in step (1) were placed in a hydrothermal reactor at a solid-liquid ratio of 5:1 and reacted at 120° C. for 3 h.
[0040] (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
[0041] The results showed that the hemicellulose extraction rate was 73.18%, the cellulose and lignin retention rates were 98.03% and 85.62% respectively, the total sugar and reducing sugar extraction rates were 34.96% and 17.67% respectively, and the average degree of polymerization was 1.98.
[0042] Example 4
[0043] A method for rapidly extracting hemicellulose components from sugarcane tail leaves by dry pretreatment, comprising the following steps:
[0044] (1) MAA was prepared by mixing a, b and c in a volume ratio of 340:400:1.
[0045] (2) Sugarcane tail leaves and the MAA prepared in step (1) were placed in a hydrothermal reactor at a solid-liquid ratio of 1:2 and reacted at 120° C. for 3 h.
[0046] (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
[0047] The results showed that the hemicellulose extraction rate was 89.51%, the cellulose and lignin retention rates were 90.61% and 79.11% respectively, the total sugar and reducing sugar extraction rates were 40.04% and 24.48% respectively, and the average degree of polymerization was 1.64.
[0048] The product of Example 4 above was further characterized and analyzed as follows.
[0049] 1. Monosaccharide composition and content of water washing liquid
[0050] Taking the water washing liquid of Example 4 as an example, the monosaccharide components were analyzed and detected by the Thermo ICS 5000+ ion chromatography system using an electrochemical detector, and the results were 67.18% xylose, 15.15% glucose, 12% arabinose, 4.59% galactose and 1.07% rhamnose. It can be seen that the sugarcane tail leaf hemicellulose is a typical grass hemicellulose structure composed of arabinoxylan, and the side chains include arabinose, glucose, galactose and rhamnose.
[0051] 2. Surface structure of sugarcane tail leaves before and after pretreatment
[0052] Taking Example 4 as an example, Figure 1 The following is a comparison of the scanning electron microscope images of sugarcane tail leaves before and after pretreatment, where a is the original sugarcane tail leaf, b is the pretreated sugarcane tail leaf, 1 is the epidermal tissue, and 2 is the vascular tissue. The original sugarcane tail leaf is plump, with a smooth surface and a tight rigid structure. After pretreatment, these tissues collapsed, cracked and shrunken. This is mainly because the deconstruction and dissolution of most of the hemicellulose and a small amount of lignin caused the stubborn structure of the cell wall to partially break, thereby changing the tissue structure.
[0053] 3. Analysis of component functional groups
[0054] Figure 2 The infrared absorption spectra of sugarcane tail leaves before and after the pretreatment of the present invention are shown in FIG. -1 、1514cm -1 and 1460cm -1 It is the characteristic peak of lignin. After pretreatment, the intensity of this series of peaks in sugarcane tail leaves becomes stronger, indicating that the content is relatively increased; 1048cm -1 It is the characteristic peak of hemicellulose, which disappears in the sugarcane tail leaves after pretreatment. It also represents the 1032cm peak of primary and secondary alcohols of cellulose. -1 and 1060cm -1 It is highlighted, indicating that cellulose is fully exposed after a large amount of hemicellulose is extracted; 1251cm -1 The CO stretching of hemicellulose and lignin is significantly weakened in the pretreated sugarcane tail leaves, indicating that the change is mainly due to the removal of hemicellulose when the lignin does not change much. -1 ) compared to the pre-treated sugarcane tail leaf displacement of 1720cm -1 This change indicates that MAA and biomass components undergo chemical reactions during pretreatment, indicating that chemical modification is carried out simultaneously in the pretreatment method of the present invention.
[0055] In summary, after the pretreatment of the present invention, most of the hemicellulose components of the sugarcane tail leaves are dissolved into the water washing liquid, and the cellulose and lignin are mainly retained in the solid matter and are chemically modified.
[0056] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.
Claims
1. A method for rapid extraction of hemicellulose components from sugarcane tail leaves by dry pretreatment, characterized in that: The steps include: (1) Prepare MAA by mixing a, b and c in a certain volume ratio. (2) Sugarcane tail leaves and the MAA prepared in step (1) are placed in a hydrothermal reactor at a certain solid-liquid ratio and reacted at a set temperature for a suitable time. (3) Take out the sugarcane tail leaves after the reaction in step (2), soak them in 50-60° C. deionized water until they are just covered and soak for 30-40 min, vacuum filter, and continue to wash the treated materials twice with an appropriate amount of 50-60° C. deionized water. The filtrates are combined to obtain a water wash rich in hemicellulose components, and the solids are rich in cellulose and lignin.
2. The method according to claim 1, characterized in that: The volume ratio of a, b and c of the MAA in step (1) is 340:400:1 to 340:50:
1.
3. The method according to claim 1, characterized in that: The sugarcane tail leaves in step (2) are dried, crushed and sieved materials with a water content of about 8-20%.
4. The method according to claim 1, characterized in that: The solid-liquid ratio of the sugarcane tail leaves to MAA in step (2) is 1:2 to 5:1 (w / v).
5. The method according to claim 1, characterized in that: The reaction temperature in step (2) is 115-140°C.
6. The method according to claim 1, characterized in that: The reaction time of step (2) is 2 to 5 hours.
7. The method according to any one of claims 1 to 6, characterized in that: After the pretreatment in step (3), the solid content of the sugarcane tail leaves is between 8% and 60% and there is no free waste liquid.
8. The method according to any one of claims 1 to 6, characterized in that: The solids rich in cellulose and lignin described in step (3) are chemically modified.