System and method for extracting cellulose, lignin and hemicellulose

Abstract

The invention discloses a system and method for extracting cellulose, lignin and hemicellulose.The system comprises pretreatment equipment, an extractor, a solvent tank, a solvent recovery system, a spraying bin, a dissolution and removal tower, a hydrolysis pool, an enzymolysis pool, purification equipment and a dryer. The solvent recycling system is used for realizing the recycling of the solvent, the pollution of the traditional black liquor is avoided, the emission is reduced through tail gas absorption and dust removal equipment, and the recycled condensate water can be recycled, so that the environmental protection benefit is obviously improved; meanwhile, hemicellulose is converted into xylooligosaccharide with high additional value, and the product quality is ensured and the resource value is greatly improved through multi-step purification such as filtration, decoloration and evaporation.

Description

Technical Field

[0001] This invention relates to the field of biomaterial manufacturing, and in particular to a system and method for extracting cellulose, lignin and hemicellulose using biomaterials. Background Technology

[0002] Pulping and papermaking is a traditional industry. Pulping is the process of removing most of the lignin and some hemicellulose from plant materials to obtain cellulose pulp. Plant materials undergo chemical and mechanical pulping to obtain pulp and waste liquor. The pulp containing waste liquor is washed to obtain clean pulp, which is then bleached to obtain white pulp. This is further processed into paper or paperboard. The main methods used in pulping include the use of chemicals such as acids, alkalis, and salts, such as the caustic soda process, sulfate process, and sulfite process. These methods are currently the most widely used pulping methods in industry.

[0003] Current pulp and paper production lines generally suffer from the following defects: 1. High equipment investment: Alkali recovery investment accounts for more than 30% of the total project investment, with high investment and operating costs; traditional pulping plants also require the construction of huge wastewater treatment plants, with high investment and operating costs; 2. Significant pollution and resource waste: Traditional pulping black liquor contains a large amount of salt, making purification extremely difficult. Generally, the black liquor is evaporated, burned, and causticized to recover caustic soda, which only solves part of the environmental pollution problem. White mud brings new pollution. Furthermore, the lignin and hemicellulose extracted can only be used as fuel and cannot be utilized at high value, resulting in serious waste of resources. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides a system and method for extracting cellulose, lignin and hemicellulose, so as to solve the problems existing in the background art.

[0005] This invention provides the following technical solution: a system for extracting cellulose, lignin, and hemicellulose, comprising: pretreatment equipment, extractor, solvent tank, solvent recovery system, spray chamber, solvent extraction tower, hydrolysis tank, enzymatic hydrolysis tank, purification equipment, and dryer; The pretreatment equipment is used to transport, remove iron, screen and store biomass raw materials. The extractor is connected to the solvent tank and uses the provided solvent to extract the biomass multiple times to separate the cellulose particles containing the solvent and the extract containing the solvent, lignin and hemicellulose. The spray chamber is used to spray and depressurize the extracted cellulose containing solvent, allowing some of the solvent to vaporize and enter the solvent recovery system for cooling and recovery. The solvent stripping tower is used to strip and desolvent the solid cellulose containing solvent after depressurization, allowing the remaining solvent in the solid cellulose to vaporize and also enter the solvent recovery system for cooling and recovery. The solvent recovery system is also used for distillation extraction to separate the solvent and the mixture containing lignin and hemicellulose. The hydrolysis tank is connected to the solvent recovery system to extract a mixture containing lignin and hemicellulose, and hydrolyze and separate lignin and a solution containing hemicellulose. The enzymatic hydrolysis tank is connected to the hydrolysis tank to extract a solution containing hemicellulose and convert the hemicellulose solution into a xylooligosaccharide solution. The purification equipment is connected to the enzymatic hydrolysis tank and also includes a filtration mechanism, an ion exchange column, and an MVR evaporation station for filtering, decolorizing, and evaporating the xylooligosaccharide solution to obtain syrup. The dryer is connected to the purification equipment for drying the syrup to obtain xylooligosaccharides.

[0006] Preferably, the pretreatment equipment includes a screw conveyor, two scraper conveyors, an iron remover, a bamboo sieve, and a hopper. The screw conveyor is connected to one of the scraper conveyors at the end for conveying materials. An iron remover is installed between them. A bamboo sieve is installed at the outlet of the scraper conveyor. A hopper is installed below the bamboo sieve. An auger is installed at the bottom of the hopper. The auger is connected to the other scraper conveyor for feeding materials.

[0007] Preferably, the extractor further includes three extraction tanks, a recovery tank, a pharmaceutical circulation pump, and a transfer pump. One extraction tank is connected to a solvent tank, and the other extraction tanks and recovery tanks are sequentially connected to each other and connected to the pharmaceutical circulation pump and transfer pump via pipes and butterfly valves. The solvent in the multiple extraction tanks is sequentially transported to the extractor for extraction by the pharmaceutical circulation pump, and the extracted liquid is recovered to the next extraction tank until it enters the recovery tank. The extracted liquid in the recovery tank is then transported to the solvent recovery system for distillation and separation by the transfer pump.

[0008] Preferably, a collector is provided above both the spray chamber and the solvent extraction tower to collect the vaporized solvent in the chamber / tower and transport it to the solvent recovery system for cooling and recovery.

[0009] Preferably, the solvent recovery system includes a first condenser, a flash tank, an evaporator, a stripping tower, a second condenser, a second steam heater, a concentrated mixture tank, and a concentrated mixture pump. The recovery tank is connected to the evaporator, which is connected to the flash tank for crude distillation. The flash tank is also connected to the stripping tower, which is connected to the second steam heater and the second condenser for fine distillation. The first condenser is equipped with multiple units respectively connected to the flash tank, the stripping tower, and a collector for converting the gaseous solvent into a liquid state. The outlet of the stripping tower is connected to the concentrated mixture tank, which is connected to the concentrated mixture pump for transporting the mixture containing lignin and hemicellulose to the hydrolysis tank.

[0010] Preferably, the outlet of the solvent extraction tower is also equipped with a packaging machine for packaging cellulose particles.

[0011] Preferably, the hydrolysis tank further includes a dehydration pump and a centrifuge, wherein the dehydration pump is used to transport the hydrolyzed lignin powder and the supernatant containing hemicellulose to the centrifuge for separation.

[0012] Preferably, the filtration mechanism includes a ceramic filter, an ultrafiltration tank, an ultrafiltration pump, and an ultrafiltration unit arranged in sequence.

[0013] Preferably, the MVR evaporation station includes a dilute sugar solution tank, a heater, a condensate tank, an evaporator, an evaporation circulation pump, a condensate tank, a condensate recovery tank, an MVR pump condensate tank, an MVR pump, and a concentrated sugar tank. The dilute sugar solution tank, heater, condensate tank, and evaporator form an evaporation unit. An evaporation circulation pump is also installed at the top of the evaporator. The exhaust port of the evaporation circulation pump is connected to the bottom of the evaporator to extract and circulate the steam in the evaporator. The exhaust port of the evaporator is connected to the MVR pump for pressurization. The MVR pump is also connected to the MVR pump condensate tank. The condensate tank and the MVR pump condensate tank are connected to the condensate recovery tank.

[0014] A method for extracting cellulose, lignin, and hemicellulose includes the following steps: S1: Pre-treatment of biomass raw materials, including conveying, iron removal, sieving, and storage of biomass raw materials; S2: The processed biomass raw material is extracted three times to separate cellulose particles containing solvent and extract containing solvent, lignin and hemicellulose. S3: Depressurize and strip the cellulose particles containing solvent to vaporize and condense the solvent for recovery, thereby obtaining solvent liquid and cellulose. S4: Distill the extract containing solvent, lignin, and hemicellulose to vaporize and condense the solvent for recovery, in order to obtain a solvent liquid and a concentrated mixture containing lignin and hemicellulose. S5: Hydrolyze a concentrated mixture containing lignin and hemicellulose, and separate it by centrifugation to obtain lignin and a supernatant containing hemicellulose. S6: Add xylanase to the supernatant containing hemicellulose to convert the hemicellulose supernatant into a xylooligosaccharide solution; S7: Filter, decolorize, and evaporate the xylooligosaccharide solution to obtain syrup; S8: Dry the syrup to obtain xylooligosaccharides.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention eliminates the need for large-scale alkali recovery equipment and wastewater treatment plants, reducing the high investment in related equipment and lowering operating costs.

[0016] 2. This invention utilizes a solvent recovery system to efficiently recover and reuse solvents, avoiding pollution problems generated during traditional pulping black liquor treatment. It also incorporates a tail gas absorption tower and a bag filter to reduce environmental pollution from tail gas and dust. Simultaneously, the recovered condensate can be recycled back to a cooling tower or boiler room soft water tank for reuse, achieving water resource recovery and further reducing pollution.

[0017] 3. This invention converts hemicellulose into xylooligosaccharides, and in the preparation process of xylooligosaccharides, multiple purification processes such as filtration, decolorization, and evaporation are used to ensure product quality, improve the utilization value of biomass resources, and avoid serious waste of resources.

[0018] 4. This invention uses an organic solvent method to extract lignin, replacing the traditional strong alkali and strong acid methods. This method gently protects the main bonds of the lignin molecule, and the organic solvent has good selectivity for dissolving lignin, is easy to recover, and does not introduce a large number of inorganic impurities. This results in the extracted lignin having the characteristics of long molecular chains and high purity, thereby expanding the applications of lignin.

[0019] 5. The various devices in this invention are reasonably connected and work together to ensure the stable operation of the system. At the same time, the MVR evaporation station reduces energy consumption and achieves energy-saving effects by recycling steam. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the pretreatment equipment of the present invention.

[0021] Figure 2 This is a schematic diagram of the three-element separation and solvent recovery process of the present invention.

[0022] Figure 3 This is a schematic diagram of the lignin and hemicellulose production process of the present invention.

[0023] The attached figures are labeled as follows: 1. Pretreatment equipment; 11. Screw conveyor; 12. Scraper conveyor; 13. Iron remover; 14. Bamboo sieve; 15. Hopper; 16. Screw conveyor; 2. Extractor; 21. First extract tank; 22. Second extract tank; 23. Third extract tank; 24. Recovery tank; 25. Chemical circulation pump; 26. Transfer pump; 27. Chemical heater; 3. Solvent tank; 31. Solvent collection tank; 4. Solvent recovery system; 41. First condenser; 42. Flash tank; 43. Evaporator; 44. Stripping tower; 45. Second condenser; 46. Second steam heater; 47. Concentrated mixture tank; 48. Concentrated mixture pump; 5. Discharge chamber; 6. Solvent-desorption tower; 7. Hydrolysis tank; 8. Enzymatic hydrolysis tank; 9. Purification equipment; 91. Filtration system; 911, Ceramic filter; 912, Ultrafiltration tank; 913, Ultrafiltration pump; 914, Ultrafiltration unit; 92, Ion exchange column; 93, MVR evaporation station; 931, Dilute sugar solution tank; 932, Heater; 933, Condensate tank; 934, Evaporator; 935, Evaporation circulation pump; 936, Condensate tank; 937, Condensate recovery tank; 938, MVR pump condensate tank; 939, MVR pump; 940, Concentrated sugar tank; 10, Dryer; 101, Hot air blower; 11, First baler; 12, Dehydration pump; 13, Centrifuge; 14, Concentrator; 15, Second baler; 16, Steam separator; 17, Cooling tower; 18, Collector; 19, Tail gas absorption tower; 20, Bag filter dust collector; 21, Bag filler. Detailed Implementation

[0024] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0025] This invention provides a system for extracting cellulose, lignin, and hemicellulose, such as... Figure 1-3 As shown, it includes: pretreatment equipment 1, extractor 2, solvent tank 3, solvent recovery system 4, spray chamber 5, solvent extraction tower 6, hydrolysis tank 7, enzymatic hydrolysis tank 8, purification equipment 9, and dryer 10.

[0026] The pretreatment equipment 1 includes a screw conveyor 11, two scraper conveyors 12, an iron separator 13, a bamboo sieve 14, and a hopper 15. The screw conveyor 11 is connected end-to-end to one of the scraper conveyors 12 for conveying materials. An iron separator 13 is installed between them to remove iron impurities from the raw materials. A bamboo sieve 14 is installed at the discharge port of the scraper conveyor 12, and a hopper 15 is installed below the bamboo sieve 14. The materials conveyed to the hopper 15 are screened by the bamboo sieve 14 to filter out larger particles. An auger 16 is installed at the bottom of the hopper 15 to discharge materials from the hopper 15. The auger 16 is connected to the other scraper conveyor 12 for feeding, and finally the materials are conveyed to the extractor 2.

[0027] The extractor 2 is also equipped with a first extraction tank 21, a second extraction tank 22, a third extraction tank 23, a recovery tank 24, a drug circulation pump 245, and a transfer pump 26. The first extraction tank 21, the second extraction tank 22, the third extraction tank 23, and the recovery tank 24 are interconnected in sequence, and are all connected to the drug circulation pump 245 and the transfer pump 26 through pipes and butterfly valves.

[0028] The top of the extractor 2 is also equipped with a spiral feeding mechanism for receiving materials. The extractor 2 is connected to the solvent tank 3 so that the solvent in the solvent tank 3 is transported to the extractor 2 to undergo a displacement reaction with the material, thereby extracting an extract containing solvent, lignin and hemicellulose from the material.

[0029] It should be noted that the solvent used in this embodiment is an organic solvent, such as ethanol, acetic acid, or ethanol and formic acid, wherein ethanol accounts for 95%.

[0030] Traditional strong bases and acids, while breaking the bonds between lignin and cellulose, also violently and indiscriminately attack the chemical bonds (β-O-4 ether bonds and carbon-carbon bonds) of the lignin molecules themselves, leading to broken molecular chains, shorter molecular chains, and the production of inorganic salt impurities, resulting in lower purity.

[0031] The organic solvent method for extracting lignin replaces the traditional strong alkali and strong acid method, which gently protects the main bonds (β-O-4 ether bonds) of the lignin molecule. Furthermore, the organic solvent has good selectivity for dissolving lignin, is easy to recover, and does not introduce a large number of inorganic impurities. This results in the extracted lignin having the characteristics of long molecular chains and high purity, thereby expanding the applications of lignin.

[0032] The extraction principle is as follows: The third extraction tank 23 is connected to the solvent tank 3 and is used to store the initial solvent. The chemical circulation pump 245 first transports the third extraction tank 23 to the extractor 2 for the first reaction. The solvent liquid after the reaction is then recovered to the second extraction tank 22. The chemical circulation pump 245 then transports the chemical liquid from the second extraction tank 22 to the extractor 2 for the second reaction. The solvent liquid after the reaction is then recovered to the third extraction tank 23. The chemical circulation pump 245 then transports the chemical liquid from the third extraction tank 23 to the extractor 2 for the third reaction. The solvent liquid after the reaction is then recovered to the recovery tank 24. At this time, the black liquor concentration in the recovery tank 24 is the highest, which is the extract containing a large amount of solvent, lignin, and hemicellulose.

[0033] It can be noted that the liquid circulation pump 245 is also equipped with a liquid heater 27, so that the cooled solvent can be heated in time each time the circulating solvent is used, so as to ensure the reaction effect with the material.

[0034] After undergoing three reactions, the material enters the discharge chamber 5 for depressurization. Part of the solvent in the material vaporizes and enters the solvent recovery system 4 for recovery. The depressurized material then re-enters the solvent stripping tower 6, which is connected to a first steam heater 932 to strip the material, causing the remaining solvent in the material to vaporize and enter the solvent recovery system 4 for recycling. The recovered solvent first enters the solvent collection tank 31 and then flows into the solvent tank 3 for storage.

[0035] It can be noted that the vaporized solvent in the spray chamber 5 and the solvent extraction tower 6 is collected by the collector 18 connected at the top. The collector 18 is connected to the solvent recovery system 4, which cools and recovers the vaporized solvent in the conveyor.

[0036] The remaining material is discharged from the solvent extraction tower 6 and packaged to meet standards by the first packaging machine 11. This packaging machine uses a hydraulic system, which saves steam consumption and facilitates storage.

[0037] The liquid in the recovery tank 24, which is an extract containing a large amount of solvent, lignin, and hemicellulose, is transported to the solvent recovery system 4 by the transfer pump 26 for distillation separation of the solvent liquid and the mixture containing lignin and hemicellulose.

[0038] The principle of distillation is as follows: The solvent recovery system 4 includes multiple first condensers 41, two flash tanks 42, two evaporators, a stripping tower 44, a second condenser 45, a second steam heater 46, a concentrated mixture tank 47, and a concentrated mixture pump 48. Each flash tank 42 and one evaporator form a group, and the two evaporators and flash tanks 42 are connected in parallel. The recovery tank 24 is connected to the first evaporator, and the second evaporator is connected to the stripping tower 44. The stripping tower 44 is also connected to the second steam heater 46 and the second condenser 45. The mixture containing lignin and hemicellulose first enters the two evaporators for rough distillation, and then enters the stripping tower 44 for fine distillation.

[0039] Multiple first condensers 41 are respectively connected to the evaporator, flash tank 42, stripping tower 44 and collector 18, used to cool the gaseous solvent into liquid state. The liquid solvent first enters the solvent collection tank 31 and then flows into the solvent tank 3 for storage.

[0040] Multiple first condensers 41 are also connected to tail gas absorption tower 19 to remove tail gas generated during condensation and avoid environmental pollution.

[0041] The outlet of the stripping tower 44 is connected to the concentrated mixture tank 47. The concentrated mixture after distillation enters the concentrated mixture tank 47, and the concentrated mixture containing lignin and hemicellulose is transported to the hydrolysis tank 7 by the concentrated mixture pump 48.

[0042] Hydrolysis tank 7 utilizes the properties that lignin is insoluble in water while hemicellulose is soluble in water to separate the two, obtaining a supernatant of precipitated lignin and hemicellulose.

[0043] A dehydration pump 12 and a centrifuge 13 are also provided on one side of the hydrolysis tank 7. The dehydration pump 12 is used to transport the lignin precipitated after hydrolysis and the supernatant containing hemicellulose to the centrifuge 13 for separation. The obtained lignin is dried in a concentration tank 14 to obtain lignin granules. A second packaging machine 15 is also provided at the discharge port of the concentration tank 14 for packaging the lignin.

[0044] The supernatant of the separated hemicellulose is transported to enzymatic hydrolysis tank 8, where xylanase is added to convert the hemicellulose supernatant into a xylooligosaccharide solution.

[0045] The xylooligosaccharide solution is first coarsely filtered through a ceramic filter 911 in the filtration mechanism 91 to remove lignin. The filter has a pore size in the millimeter range. Then, it undergoes fine filtration through an ultrafiltration tank 912, an ultrafiltration pump 913, and an ultrafiltration unit 914, all part of the filtration mechanism 91. The pore size is in the micrometer range, effectively filtering out particles of varying sizes from the solution. The filtered solution is then adsorbed through an ion exchange column 92. Utilizing the charged nature of the pigments, electrostatic interactions between the pigments and the functional groups on the ion exchange resin achieve adsorption and decolorization.

[0046] The filtered and decolorized xylooligosaccharide solution is pumped into the MVR evaporation station 93 via pump 939 for evaporation to produce syrup. The specific operation is as follows: The MVR evaporation station 93 includes a dilute sugar solution tank 931, a heater 932, a condensate tank 933, an evaporator 934, an evaporation circulation pump 935, a condensate tank 936, a condensate recovery tank 937, an MVR pump condensate tank 938, an MVR pump 939, and a concentrated sugar tank 940.

[0047] The dilute sugar solution tank 931 is used to store the filtered and decolorized xylooligosaccharide solution. The heater 932 preheats the xylooligosaccharide solution, increases the feed temperature, and reduces the heat load of the evaporator body. The xylooligosaccharide solution is heated to boiling in the evaporator, the water is evaporated and separated, and the remaining syrup is transported to the concentrated sugar tank 940 for collection.

[0048] The heater 932, condensate tank 933, and evaporator 934 form an evaporation unit. The exhaust port of the evaporation circulation pump 935 is connected to the bottom of the evaporator to circulate and evaporate the sugar solution inside the evaporator.

[0049] The evaporator's exhaust port is connected to the MVR pump 939 for pressurization, increasing the steam pressure and temperature, and then sending it back into the heater 932 for continued use. The MVR pump 939 is also connected to the MVR pump condensate tank 938 to collect condensate that may be generated from the MVR pump 939. The condensate tank 933 and the MVR pump condensate tank 938 are connected together to the condensate recovery tank 937 to collect the condensate from the condensate tank 933 and the MVR pump condensate tank 938.

[0050] The syrup is then transported to the dryer 10 for drying. A hot air blower 101 is provided on one side of the dryer 10 and a sugar collector is provided on the other side. Hot air generated by the hot air blower 101 is blown in from the top of the dryer 10 to dry the syrup and obtain xylooligosaccharides.

[0051] A bagger 21 is also provided at the bottom of the sugar collector for packaging xylooligosaccharides.

[0052] The sugar collector is also connected to a bag filter dust collector 20, which is used to remove dust particles generated during drying to avoid environmental pollution.

[0053] In this embodiment, the steam source is a boiler room. A steam distribution cylinder 16 is installed at the steam source location. The steam is transported through the steam distribution cylinder 16 and pipelines to equipment such as the extractor 2, the liquid heater 27, the steam heater 932, the evaporator, the flash tank 42, and the steam heater 932 to provide heat energy.

[0054] In this embodiment, a cooling water tower 17 is also provided. The cooling water tower 17 pipes and water pump 939 provide water for the condenser, hydrolysis tank 7 and enzymatic hydrolysis tank 8. The condensate from the condensate recovery tank 937 is then returned to the cooling water tower 17 or returned to the boiler room soft water tank for continued use, thus forming a water resource recycling system.

[0055] A method for extracting cellulose, lignin, and hemicellulose, based on the aforementioned pretreatment equipment, extractor, solvent tank, solvent recovery system, spray chamber, solvent extraction tower, hydrolysis tank, enzymatic hydrolysis tank, purification equipment, and dryer, includes the following steps: S1: Pre-treatment of biomass raw materials, which involves conveying, removing iron, screening, and storing biomass raw materials through pre-treatment equipment; S2: The treated biomass raw material is extracted three times using an extractor to separate solid cellulose containing solvent and extract containing solvent, lignin and hemicellulose. S3: Solid cellulose containing solvent is sprayed, depressurized, and stripped through a spray chamber and a solvent stripping tower to vaporize and condense the solvent for recovery, thereby obtaining solvent liquid and cellulose. The vaporized solvent is then transported to a solvent recovery system for recycling. S4: The extract containing solvent, lignin, and hemicellulose is distilled through a solvent recovery system to vaporize and condense the solvent for recovery, thereby obtaining a solvent liquid and a concentrated mixture containing lignin and hemicellulose. The concentrated mixture containing lignin and hemicellulose is then transported to a hydrolysis tank for hydrolysis treatment. S5: Hydrolyze a concentrated mixture containing lignin and hemicellulose, and separate it by centrifugation to obtain lignin and a supernatant containing hemicellulose. S6: Add xylanase to the supernatant containing hemicellulose to convert the hemicellulose supernatant into a xylooligosaccharide solution; S7: Filter, decolorize, and evaporate the xylooligosaccharide solution to obtain syrup; S8: Dry the syrup to obtain xylooligosaccharides.

[0056] In summary, the present invention has the following advantages: 1. This invention eliminates the need for large-scale alkali recovery devices and wastewater treatment plants required for traditional pulping processes, reducing high investment in related equipment and lowering operating costs. 2. This invention utilizes a solvent recovery system for efficient solvent recycling, avoiding pollution problems associated with traditional black liquor treatment. Furthermore, it incorporates equipment such as tail gas absorption towers and bag filters to reduce environmental pollution from tail gas and dust. Condensate can be recycled to cooling towers or boiler room soft water tanks, achieving water resource recovery and further reducing pollution. 3. This invention no longer uses the extracted lignin and hemicellulose solely as fuel. Instead, it separates lignin through a series of processes and converts hemicellulose into xylooligosaccharides, improving the utilization value of biomass resources and avoiding serious resource waste. 4. This invention employs an organic solvent extraction method for lignin, replacing traditional strong alkali and strong acid methods. This method gently protects the lignin molecular bonds, and the organic solvent exhibits good selectivity for lignin dissolution, is easy to recover, and does not introduce large amounts of inorganic impurities. This results in extracted lignin with long molecular chains and high purity, thereby expanding the applications of lignin. 5. The various devices in this invention are reasonably connected and work together to ensure the stable operation of the system; the MVR evaporation station reduces energy consumption by recycling steam and has a good energy-saving effect.

[0057] Several points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change.

[0058] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. A system for extracting cellulose, lignin, and hemicellulose, characterized in that... It includes: pretreatment equipment, extractor, solvent tank, solvent recovery system, spray chamber, solvent extraction tower, hydrolysis tank, enzymatic hydrolysis tank, purification equipment, and dryer; The pretreatment equipment is used for conveying, removing iron, screening and storing biomass raw materials; the extractor is connected to the solvent tank and uses the provided solvent to extract the biomass multiple times to separate solid cellulose containing solvent and extract containing solvent, lignin and hemicellulose. The spray chamber is used to spray and depressurize the extracted cellulose containing solvent, allowing some of the solvent to vaporize and enter the solvent recovery system for cooling and recovery. The solvent stripping tower is used to strip and desolvent the solid cellulose containing solvent after depressurization, allowing the remaining solvent in the solid cellulose to vaporize and also enter the solvent recovery system for cooling and recovery. The solvent recovery system is also used for distillation extraction to separate the solvent and the mixture containing lignin and hemicellulose. The hydrolysis tank is connected to the solvent recovery system for the hydrolysis of hemicellulose and the precipitation and separation of lignin; the enzymatic hydrolysis tank is connected to the hydrolysis tank to convert the hemicellulose solution into a xylooligosaccharide solution; the purification equipment is connected to the enzymatic hydrolysis tank, and the purification equipment also includes a filtration mechanism, an ion exchange column, and an MVR evaporation station for filtering, decolorizing, and evaporating the xylooligosaccharide solution to obtain syrup; the dryer is connected to the purification equipment for drying the syrup to obtain xylooligosaccharides.

2. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The pretreatment equipment includes a screw conveyor, two scraper conveyors, an iron remover, a bamboo sieve, and a hopper. The screw conveyor is connected to one of the scraper conveyors at the end for conveying materials. An iron remover is installed between them. A bamboo sieve is installed at the outlet of the scraper conveyor. A hopper is installed below the bamboo sieve. An auger is installed at the bottom of the hopper and is connected to the other scraper conveyor for feeding materials.

3. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The extractor also includes three extraction tanks, a recovery tank, a pharmaceutical circulation pump, and a transfer pump. One extraction tank is connected to a solvent tank, and the other extraction tanks and recovery tanks are connected to each other in sequence. They are also connected to the pharmaceutical circulation pump and the transfer pump via pipes and butterfly valves. The solvent in the multiple extraction tanks is sequentially transported to the extractor for extraction by the pharmaceutical circulation pump. The extracted liquid is then recovered to the next extraction tank until it enters the recovery tank. The extracted liquid in the recovery tank is then transported to the solvent recovery system for distillation and separation by the transfer pump.

4. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: Both the spray chamber and the solvent extraction tower are equipped with traps to collect the vaporized solvent in the chamber / tower and transport it to the solvent recovery system for cooling and recovery.

5. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The solvent recovery system includes a first condenser, a flash tank, an evaporator, a stripping tower, a second condenser, a second steam heater, a concentrated mixture tank, and a concentrated mixture pump. The recovery tank is connected to the evaporator, which is connected to the flash tank for crude distillation. The flash tank is also connected to the stripping tower, which is connected to the second steam heater and the second condenser for fine distillation. The first condenser has multiple components connected to the flash tank, the stripping tower, and a collector to convert the gaseous solvent into a liquid state. The outlet of the stripping tower is connected to the concentrated mixture tank, which is connected to the concentrated mixture pump to transport the mixture containing lignin and hemicellulose to the hydrolysis tank.

6. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The outlet of the solvent extraction tower is also equipped with a packaging machine for packaging solid cellulose.

7. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The hydrolysis tank also includes a dehydration pump and a centrifuge. The dehydration pump is used to transport the hydrolyzed lignin precipitate and the supernatant containing hemicellulose to the centrifuge for separation.

8. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The filtration mechanism includes a ceramic filter, an ultrafiltration tank, an ultrafiltration pump, and an ultrafiltration unit arranged in sequence.

9. The system for extracting cellulose, lignin, and hemicellulose according to claim 1, characterized in that: The MVR evaporation station includes a dilute sugar solution tank, a heater, a condensate tank, an evaporator, an evaporation circulation pump, a condensate tank, a condensate recovery tank, an MVR pump condensate tank, an MVR pump, a concentrated sugar tank, and the dilute sugar solution tank, heater, condensate tank, and evaporator form an evaporation unit. An evaporation circulation pump is installed at the bottom of the evaporator, and the exhaust port of the evaporation circulation pump is connected to the bottom of the evaporator to circulate and evaporate the evaporated liquid to achieve the required concentration. The exhaust port of the evaporator is connected to the MVR pump, and the steam is recycled after being pressurized. The condensate is connected to the MVR pump condensate tank, and the condensate tank and the MVR pump condensate tank are connected to the condensate recovery tank.

10. A method for extracting cellulose, lignin, and hemicellulose, based on the system for extracting cellulose, lignin, and hemicellulose according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Pre-treatment of biomass raw materials, including transportation, iron removal, screening, and storage of biomass raw materials; S2: The processed biomass raw material is extracted three times to separate solid cellulose containing solvent and extract containing solvent, lignin and hemicellulose. S3: The solid cellulose containing solvent is sprayed, depressurized, and stripped to vaporize and condense the solvent for recovery, thereby obtaining the solvent and cellulose. S4: The extract containing solvent, lignin, and hemicellulose is distilled to vaporize and condense the solvent for recovery, in order to obtain a solvent liquid and a concentrated mixture containing lignin and hemicellulose. S5: Hydrolyze a concentrated mixture containing lignin and hemicellulose, and separate it by centrifugation to obtain lignin and a supernatant containing hemicellulose. S6: Add xylanase to the supernatant containing hemicellulose to convert the hemicellulose supernatant into a xylooligosaccharide solution; S7: Filter, decolorize, and evaporate the xylooligosaccharide solution to obtain syrup; S8: Dry the syrup to obtain xylooligosaccharides.

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