Comprehensive utilization method of bagasse and equipment and application thereof

Abstract

The invention provides a comprehensive utilization method of bagasse as well as equipment and application thereof. The method comprises the following steps: hydrolyzing bagasse under an acidic condition, and filtering to obtain hydrolysate containing xylose and hemicellulose-removed waste residues; extracting and filtering the hemicellulose-removed waste residue under an alkaline condition to obtain cellulose and alkaline lignin filtrate; according to the method, hemicellulose, cellulose and lignin in bagasse are separated, specifically, hemicellulose is hydrolyzed under the acidic condition and converted into xylose and hemicellulose-removed waste residues containing cellulose and lignin, and the xylose can be used for preparing xylose products; then the hemicellulose-removed waste residues are subjected to a reaction under the alkaline condition, cellulose and lignin are separated, the separated lignin can be used for preparing a stable lignin material, and the separated cellulose can be used for papermaking or viscose fiber preparation. According to the method, maximum development of bagasse resources is achieved, and comprehensive economic benefits and environmental benefits of the sugarcane sugar manufacturing industry are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of bagasse extraction, and in particular to a comprehensive utilization method of bagasse, equipment and application thereof. Background Art

[0002] Sugarcane, as an important sugar crop, plays a key role in the sugar industry. The sugarcane sugar production process produces a large amount of bagasse. Guangxi Zhuang Autonomous Region, China's largest sugarcane producing region, produces over 12 million tons (dry basis) of bagasse annually. Bagasse's main components are cellulose (40%-50%), hemicellulose (25%-30%), and lignin (18%-22%). Currently, bagasse is primarily used for power generation, but this combustion method is inefficient (burning four tons of bagasse only produces the equivalent of one ton of coal, with a calorific value of only one-quarter that of coal). It also generates significant environmental pollution (such as large amounts of smog and other harmful gases), negatively impacting human health and air quality. With growing environmental awareness and the promotion of sustainable development concepts, the efficient and environmentally friendly utilization of bagasse resources has become a pressing issue.

[0003] Currently, Chinese patent CN119955878A discloses a method for producing xylooligosaccharides, using corn cobs and sugarcane bagasse as raw materials. The method involves removing impurities, pulverizing, and spraying acid to soak the sugars. Although this method provides a way to utilize sugarcane bagasse, it still faces technical bottlenecks in practical applications: only hemicellulose is converted into xylooligosaccharides, while the cellulose and lignin, which account for approximately 58%-72% of the bagasse, are not effectively separated and utilized, resulting in resource waste. Summary of the Invention

[0004] The present invention aims to solve the problem of low comprehensive utilization efficiency of bagasse resources in the prior art and provides a comprehensive utilization method and equipment for bagasse.

[0005] The technical method of the present invention is as follows: A comprehensive utilization method of sugarcane bagasse comprises: hydrolyzing and filtering the sugarcane bagasse under acidic conditions to obtain a hydrolyzate containing xylose and a hemicellulose-removed waste residue; and extracting and filtering the hemicellulose-removed waste residue under alkaline conditions to obtain a cellulose and alkaline lignin filtrate.

[0006] The bagasse has a particle size of 20-40 meshes and a moisture content of 8%-10%.

[0007] The acidic conditions for bagasse hydrolysis are to add a sulfuric acid solution with an acidity of 0.9%-1.1%, a hydrolysis temperature of 116-120°C, and a hydrolysis time of 2-2.5 hours. The ratio of dry bagasse to sulfuric acid solution is 0.5-1.5 kg: 2.5-7.5 L.

[0008] The alkaline conditions for bagasse extraction are to add sodium hydroxide solution with a concentration of 0.3%-0.5%, an extraction temperature of 100-105°C, and an extraction time of 2-2.1 hours. The ratio of hemicellulose-removed waste residue to sodium hydroxide solution is 0.5-1.5 kg: 2.5-7.5 L.

[0009] The method further includes: deacidifying and concentrating the xylose-containing hydrolyzate to obtain high-purity xylose; adjusting the pH of the alkaline lignin filtrate to 1.8-2.3 and centrifuging to obtain high-purity lignin; bleaching, drying, and forming the cellulose to obtain paper; or aging and xanthochromizing the cellulose to obtain viscose fiber.

[0010] The present invention provides a comprehensive utilization device for bagasse, which comprises a bagasse acidic hydrolysis device, a first plate-frame filter press device, an alkali extraction reaction device, and a second plate-frame filter press device; wherein the bagasse acidic hydrolysis device is a hydrolysis reactor, and the hydrolyzate discharge port of the hydrolysis reactor is connected to the hydrolyzate feed port of the first plate-frame filter press device; the alkali extraction reaction device is an alkali extraction reactor, and a stirring rod is installed in the alkali extraction reactor, the hemicellulose-removed waste residue feed port of the alkali extraction reaction device is connected to the hemicellulose-removed waste residue discharge port of the first plate-frame filter press device, and the alkali extraction mixed liquid discharge port of the alkali extraction reaction device is connected to the alkali extraction mixed liquid feed port of the second plate-frame filter press device.

[0011] The invention provides a comprehensive utilization method of bagasse and its application in papermaking and viscose fiber.

[0012] The beneficial effects of the present invention are: The present invention separates hemicellulose, cellulose, and lignin from sugarcane bagasse. Specifically, the hemicellulose is first hydrolyzed under acidic conditions to convert it into xylose and a hemicellulose-free residue containing cellulose and lignin. The xylose can be used to produce xylose products. The hemicellulose-free residue is then reacted under alkaline conditions to separate the cellulose from the lignin. The separated lignin can be used to produce stabilized lignin materials, and the separated cellulose can be used to make paper or produce viscose fibers. This method maximizes the development of sugarcane bagasse resources and significantly improves the overall economic and environmental benefits of the sugarcane sugar industry.

[0013] The acid used in the entire process of the present invention can be recycled, so that the amount of discharged substances is extremely small, and the entire process achieves green production.

[0014] In traditional processes, the separation of lignin and cellulose requires high temperatures and high alkali (130-180°C, pH>13). This is because high-concentration sodium hydroxide solution is directly used to dissolve lignin and hemicellulose. The presence of hemicellulose increases the requirements for sodium hydroxide concentration and extraction temperature. However, the present invention first removes hemicellulose through acid hydrolysis, changing the internal structure of the bagasse, thereby significantly reducing the required sodium hydroxide concentration and extraction temperature. The alkali concentration can be reduced to 0.3%-0.5%, and the extraction temperature can be lowered to 105°C. Due to the reduction in extraction temperature and sodium hydroxide solution concentration, the subsequent acid neutralization dosage is also reduced, ultimately significantly reducing the cost of separating lignin and cellulose.

[0015] The present invention adopts a plate and frame filter press device to physically separate the bagasse hydrolyzate and the alkali extraction mixed solution under alkaline conditions, which has high controllability, improves the operation efficiency, effectively avoids the introduction of new substances, and reduces the operation cost.

[0016] In the present invention, since the acidity (0.9%-1.1%) and alkalinity (0.3%-0.5%) are both low, the service life of various devices can be greatly increased, which not only increases the stability of the comprehensive utilization method of sugarcane bagasse resources, but also improves the usability of the equipment and reduces equipment loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a logical connection diagram of the combined process system in the present invention; Figure 2 Schematic diagram of the bagasse hydrolysis process in the present invention; Figure 3 This is a schematic diagram of the first plate and frame filter press workflow in the present invention; Figure 4 This is a schematic diagram of the second plate and frame filter press workflow in the present invention; Figure 5 This is a schematic diagram of the alkali extraction workflow of the present invention; Figure 6 Schematic diagram of the working principle of continuous centrifugation in the present invention.

[0018] Reference numerals: 1-Sugarcane bagasse acidic hydrolysis device, 2-Sugarcane bagasse hydrolyzate temporary storage tank, 3-First plate and frame filter press device, 4-Xylose solution temporary storage tank, 5-Dehemicelvose waste residue temporary storage tank, 6-Alkali extraction reaction device, 7-Alkali extraction mixed liquid temporary storage tank, 8-Second plate and frame filter press device, 9-Cellulose temporary storage area, 10-Alkaline lignin filtrate temporary storage tank, 11-Continuous centrifugation device, 12-Lignin temporary storage area, 13-Filtrate temporary storage tank. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solution of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0020] The concept of this invention is to comprehensively utilize bagasse resources. By hydrolyzing the bagasse, hemicellulose is effectively converted into xylose, generating economic benefits. Furthermore, by removing the hemicellulose from the bagasse, the subsequent separation of lignin and hemicellulose is simplified. This entire process not only improves bagasse utilization, but also virtually achieves zero COD, acid, and salt emissions, contributing to green production and environmental protection.

[0021] The present invention provides a comprehensive utilization method of bagasse, which comprises: S1. Hydrolyzing and filtering sugarcane bagasse under acidic conditions to obtain a xylose-containing hydrolyzate and hemicellulose-removed waste residue.

[0022] Before step S1, the sugarcane bagasse is crushed and impurity removed.

[0023] In one embodiment, the bagasse comprises hemicellulose, cellulose, and lignin. The bagasse has a particle size of 20-40 mesh and a moisture content of 8%-10%. Preferably, the bagasse has a particle size of 30 mesh.

[0024] In one embodiment, hydrolysis under acidic conditions is performed to convert the hemicellulose in sugarcane bagasse into xylose. Compared to conventional hydrochloric acid and nitric acid, which are more corrosive to equipment, the acidic conditions employed in this invention include the addition of a sulfuric acid solution with an acidity of 0.9%-1.1% and a sulfuric acid content of 9-11 g / L. The hydrolysis temperature is 116-120°C, and the hydrolysis time is 2-2.5 hours. If the hydrolysis temperature is higher than 120°C, overreaction will occur, resulting in an increase in byproducts and a decrease in the yield of the target product. If the hydrolysis temperature is lower than 116°C, the reaction efficiency may drop significantly, or even cease to proceed, preventing the target product from being produced. The ratio of dry bagasse to sulfuric acid solution is 0.5-1.5 kg: 2.5-7.5 L. The xylose content in the xylose-containing hydrolyzate is approximately 50 g / L.

[0025] In one embodiment, the filtration is performed by plate and frame filter pressing, which has high controllability, improves operating efficiency, effectively avoids the introduction of new substances, and reduces operating costs.

[0026] In one embodiment, the xylose-containing hydrolyzate is deacidified and concentrated to obtain high-purity xylose. Deacidification of the xylose-containing hydrolyzate can be achieved by electrodialysis or chromatography. Concentration methods can be selected based on the feed concentration: membrane concentration can be used for low feed concentrations, while evaporation (e.g., MVR) can be used for high feed concentrations.

[0027] In one embodiment, the pH of the alkaline lignin filtrate is adjusted to 1.8-2.3 and centrifuged to obtain high-purity lignin. The pH can be adjusted to 1.8-2.3 using a hydrochloric acid solution having a concentration of 32%-36%.

[0028] S2. Extracting and filtering the hemicellulose-removed waste residue under alkaline conditions to obtain cellulose and alkaline lignin filtrate.

[0029] In one embodiment, the alkaline condition is to add a sodium hydroxide solution with a concentration of 0.3%-0.5%. The extraction temperature is 100-105°C, and the extraction time is 2-2.1h. If the extraction temperature is higher than 105°C, overreaction will occur, resulting in an increase in by-products and a decrease in the yield of the target product; if the extraction temperature is lower than 100°C, the reaction efficiency will drop significantly, and the target product may not be generated due to the inability to proceed with the reaction. The ratio of hemicellulose removal waste residue to sodium hydroxide solution is 0.5-1.5kg:2.5-7.5L. The alkaline lignin filtrate content is ≈40g / L. In one embodiment, filtration is performed using plate and frame filter pressing. Plate and frame filter pressing has high controllability, improves operating efficiency, effectively avoids the introduction of new substances, and reduces operating costs.

[0030] In one embodiment, cellulose is bleached, dried, and formed to produce paper; the bleaching step utilizes hydrogen peroxide to destroy the structure of the colored material to achieve bleaching. Alternatively, the cellulose is aged and xanthated to produce viscose fiber. The aging step involves maintaining the pulverized cellulose at a constant temperature for a predetermined period of time to reduce the degree of polymerization to process requirements through oxidative degradation in air. The xanthation step involves reacting the cellulose with carbon disulfide to produce sodium cellulose sulfonate, which is soluble in dilute alkali solution, i.e., viscose fiber.

[0031] Specifically, the working principle of this method is as follows: during the hydrolysis of sugarcane bagasse, sulfuric acid is used as a catalyst to hydrolyze hemicellulose into xylose under certain temperature and time conditions; during plate and frame filter pressing, low-pore filter cloth is used as the filter medium to separate the solid and liquid in the mixture through physical interception; during alkaline extraction, certain functional groups in the lignin structure react with the hydroxide ions in the alkaline solution, making it soluble in the alkaline solution, while cellulose is insoluble in the alkali. Then, through physical interception, the cellulose and lignin can be separated. Furthermore, during centrifugation, the centripetal force generated by the high-speed operation of the centrifuge is used to intercept and separate the solid and liquid through the filter screen.

[0032] The present invention also provides a comprehensive utilization device for bagasse, such as Figure 1 As shown, the equipment includes a sugarcane bagasse acidic hydrolysis device 1, a first plate and frame filter press device 3, an alkali extraction reaction device 6, and a second plate and frame filter press device 8; wherein, the sugarcane bagasse acidic hydrolysis device 1 is a hydrolysis reactor, and the hydrolyzate discharge port of the hydrolysis reactor is connected to the hydrolyzate feed port of the first plate and frame filter press device 3; the alkali extraction reaction device 6 is an alkali extraction reactor, and a stirring rod is installed in the alkali extraction reactor. The hemicellulose-removed waste residue feed port of the alkali extraction reaction device 6 is connected to the hemicellulose-removed waste residue discharge port of the first plate and frame filter press device 3, and the alkali extraction mixed liquid discharge port of the alkali extraction reaction device 6 is connected to the alkali extraction mixed liquid feed port of the second plate and frame filter press device 8.

[0033] In one embodiment, if Figure 1 As shown, the bagasse acid hydrolysis device 1 can be a hydrolysis reactor. The alkaline extraction reactor 6 is equipped with a stirring rod and a stirring rate of 2000 rpm. The hydrolysis reactor is acid-resistant and high-temperature-resistant, and the alkaline extraction reactor is alkali-resistant and high-temperature-resistant.

[0034] Here, as Figure 1 As shown, the sugarcane bagasse acid hydrolysis unit 1 has a feed rate of 40-50 m³ / h and a discharge rate of 40-50 m³ / h. The first plate-and-frame filter press 3 operates at a pressure of 40-45 bar, a feed temperature of 40-50°C, a feed rate of 40-50 m³ / h, and a discharge rate of 35-45 m³ / h. The alkaline extraction reaction unit 6 has a feed rate of 38-45 m³ / h and a discharge rate of 38-45 m³ / h of xylose-containing hydrolyzate. The second plate-and-frame filter press 8 operates at a pressure of 40-45 bar, a feed temperature of 90-95°C, a feed rate of 38-45 m³ / h, and a discharge rate of 30-40 m³ / h of alkaline lignin filtrate.

[0035] In one embodiment, if Figure 1-6As shown, the equipment also includes: a bagasse hydrolyzed liquid temporary storage tank 2, a xylose solution temporary storage tank 4, a hemicellulose-removed waste residue temporary storage tank 5, an alkaline extraction mixed liquid temporary storage tank 7, a cellulose temporary storage area 9, an alkaline lignin filtrate temporary storage tank 10, a continuous centrifugation device 11, a lignin temporary storage area 12, and a filtrate temporary storage tank 13. The hydrolyzed liquid feed inlet of the bagasse hydrolyzed liquid temporary storage tank 2 is connected to the hydrolyzed liquid discharge outlet of the bagasse acidic hydrolysis unit 1, and the hydrolyzed liquid discharge outlet of the bagasse hydrolyzed liquid temporary storage tank 2 is connected to the hydrolyzed liquid feed inlet of the first plate-frame filter press unit 3. The xylose-containing hydrolyzed liquid feed inlet of the xylose solution temporary storage tank 4 is connected to the xylose-containing hydrolyzed liquid discharge outlet of the first plate-frame filter press unit 3, and the hemicellulose-removed waste residue feed inlet of the hemicellulose-removed waste residue temporary storage tank 5 is connected to the hemicellulose-removed waste residue discharge outlet of the first plate-frame filter press unit 3. The dehemicellulose waste residue feed port of the alkali extraction reaction device 6 is connected to the dehemicellulose waste residue discharge port of the dehemicellulose waste residue temporary storage tank 5. The alkali extraction mixed liquid temporary storage tank 7 is used to store the alkali extraction mixed liquid. The alkali extraction mixed liquid feed port of the alkali extraction mixed liquid temporary storage tank 7 is connected to the alkali extraction mixed liquid discharge port of the alkali extraction reaction device 6, and the alkali extraction mixed liquid discharge port of the alkali extraction mixed liquid temporary storage tank 7 is connected to the alkali extraction mixed liquid feed port of the second plate and frame filter press device 8. The cellulose discharge port of the second plate and frame filter press device 8 is connected to the feed port of the cellulose temporary storage area 9. The alkaline lignin filtrate feed port of the alkaline lignin filtrate temporary storage tank 10 is connected to the alkaline lignin filtrate discharge port of the second plate and frame filter press device 8, and the alkaline lignin filtrate discharge port of the alkaline lignin filtrate temporary storage tank 10 is connected to the alkaline lignin filtrate feed port of the continuous centrifugation device 11. The lignin outlet of continuous centrifuge 11 is connected to lignin temporary storage area 12, and the filtrate outlet of continuous centrifuge 11 is connected to filtrate temporary storage tank 13. Here, continuous centrifuge 11 is a continuous separator with a separation factor of 5000. The high-purity lignin has a moisture content of 15%-20%, and the output capacity is 1.7-1.9 t / h on a dry basis; the filtrate output flow rate is 27-31 m³ / h.

[0036] Specifically, if Figure 1-6As shown, after being pulverized and impurity-removed, the bagasse is mixed with dilute sulfuric acid and passed into a bagasse acid hydrolysis unit 1 for hydrolysis, producing a bagasse hydrolyzate. The bagasse hydrolyzate is stored in a temporary storage tank 2. The bagasse hydrolyzate (raw material) in the temporary storage tank 2 then enters a first plate-and-frame filter press 3, producing a xylose-containing hydrolyzate (filtrate) and a hemicellulose-removed waste residue (filter residue). The xylose-containing hydrolyzate is stored in a temporary storage tank 4 for xylose solution, and the hemicellulose-removed waste residue is stored in a temporary storage tank 5 for hemicellulose-removed waste residue. The hemicellulose-removed waste residue in the temporary storage tank 5 is then mixed with a sodium hydroxide solution (dilute alkali) and passed into an alkali extraction reaction unit 6 to produce an alkali extraction mixed solution. The alkali extraction mixed solution is stored in a temporary storage tank 7 for alkali extraction mixed solution. The alkaline extraction mixed liquid (raw material) in the alkaline extraction mixed liquid temporary storage tank 7 then enters the second plate and frame filter press 8, producing cellulose (filter residue) and alkaline lignin filtrate (filtrate). Here, the cellulose is stored in the cellulose temporary storage area 9, and the alkaline lignin filtrate is stored in the alkaline lignin filtrate temporary storage tank 10. The alkaline lignin filtrate in the alkaline lignin filtrate temporary storage tank 10 is neutralized with hydrochloric acid and then passed into a continuous centrifugation device 11 for centrifugation, producing high-purity lignin (filter residue) and filtrate. The high-purity lignin is stored in the lignin temporary storage area 12, and the filtrate is stored in the filtrate temporary storage tank 13.

[0037] Furthermore, each of the above-mentioned devices also includes a supporting cleaning system, including a cleaning tank, various cleaning agent adding devices and supporting pipelines.

[0038] Each delivery pipe is equipped with a flow meter, control valve and automatic control device according to actual needs.

[0039] In summary, the xylose solution of the present invention has a xylose content of >45 g / L, a xylose purity of >82%, an organic acid content of <0.1%, a chloride content of <0.005%, a cellulose moisture content of <25%, and a purity of >95%, and a lignin moisture content of <20%, and a purity of >98%.

[0040] The present invention is described in detail below by way of examples and experimental examples, which are merely illustrative and do not limit the present invention in any way. Example 1

[0041] This embodiment provides a method for comprehensive utilization of bagasse, comprising the following steps: Step 1: Sugarcane bagasse crushed to 25-35 mesh and having a moisture content of 8%-10% is used as raw material, dilute sulfuric acid with an acidity of 0.9%-1.1% is added to the raw material, and the raw material is passed into a hydrolysis reactor. Hydrolysis is carried out at 118° C. for 2 hours, and then plate and frame filter pressing is performed to obtain a xylose-containing hydrolyzate and a hemicellulose-removed waste residue. The ratio of the raw material dry basis to the dilute sulfuric acid is 1 kg:5 L, the xylose content in the xylose-containing hydrolyzate is 45-55 g / L, the lignin and cellulose content in the hemicellulose-removed waste residue is 130-140 g / L, and the sulfuric acid content is 9-11 g / L. Step 2: Add a 0.4% sodium hydroxide solution to the de-hemicellulose waste residue, pass it into an alkaline extraction reactor with a stirring rod, extract it at 101°C for 2 hours, and filter it with a plate and frame filter to obtain a cellulose and alkaline lignin filtrate; wherein the ratio of the de-hemicellulose waste residue to the sodium hydroxide solution is 1 kg:5 L, and the stirring rate is 2000 rpm; Step 3: deacidifying and concentrating the xylose-containing hydrolyzate to obtain high-purity xylose; Step 4: adjusting the pH of the alkaline lignin filtrate to 2.1 and centrifuging to obtain high-purity lignin; wherein the separation factor of the centrifugation is 5000, and hydrochloric acid is added to adjust the pH to 2.1.

[0042] Furthermore, the method of the present invention further comprises: bleaching, drying and shaping the cellulose to obtain paper; or aging and yellowing the cellulose to obtain viscose fiber. Example 2

[0043] This embodiment provides a method for comprehensive utilization of bagasse, using a comprehensive utilization device for bagasse, and the method comprises the following steps: Step 1: Using sugarcane bagasse crushed to 25-35 mesh and having a moisture content of 8%-10% as raw material, adding dilute sulfuric acid with an acidity of 0.9%-1.1% to the raw material, passing the raw material into a sugarcane bagasse acid hydrolysis device for hydrolysis at 118° C. for 2 hours, wherein the ratio of the raw material dry basis to the dilute sulfuric acid is 1 kg:5 L, the feed flow rate is 45 m³ / h, the discharge flow rate is 45 m³ / h, and the sugarcane bagasse hydrolyzate is stored in a sugarcane bagasse hydrolyzate temporary storage tank; the xylose content in the xylose-containing hydrolyzate is 45-55 g / L, the lignin and cellulose content in the dehemicellulose waste residue is 130-140 g / L, and the sulfuric acid content is 9-11 g / L; Step 2: Passing the bagasse hydrolyzate in the bagasse hydrolyzate temporary storage tank into a first plate and frame filter press to obtain a xylose-containing hydrolyzate and a dehemicellulose waste residue; wherein the first plate and frame filter press operates at a pressure of 40-45 bar, a feed temperature of 40-50°C, a feed flow rate of 45 m³ / h, a discharge flow rate of the xylose-containing hydrolyzate of 40 m³ / h, and a dehemicellulose waste residue discharge rate of 6 T / h; the xylose-containing hydrolyzate is stored in a xylose solution temporary storage tank, and the dehemicellulose waste residue is stored in a dehemicellulose waste residue temporary storage tank; Step 3: adding a sodium hydroxide solution having a concentration of 0.4% to the hemicellulose-removed waste residue, adding the solution to an alkali extraction reaction device, and extracting the solution at 101° C. for 2 hours to obtain an alkali extraction mixed solution; wherein the alkali extraction mixed solution is stored in an alkali extraction mixed solution temporary storage tank; the feed flow rate is 41 m³ / h, the discharge flow rate is 41 m³ / h, and the stirring rate of the alkali extraction reaction device is 2000 rpm; Step 4: Passing the hot alkali extraction mixture into a second plate and frame filter press to obtain cellulose and alkaline lignin filtrate; wherein the second plate and frame filter press operates at a pressure of 40-45 bar, a feed temperature of 90-95°C, a feed flow rate of 41 m³ / h, an alkaline lignin filtrate discharge flow rate of 37 m³ / h, and a cellulose residue discharge rate of 4.2 t / h. The cellulose is stored in a cellulose temporary storage area, and the alkaline lignin filtrate is stored in an alkaline lignin filtrate temporary storage tank; Step 5: deacidifying and concentrating the xylose-containing hydrolyzate in the xylose solution temporary storage tank to obtain high-concentration xylose; Step 6: Add hydrochloric acid to the alkaline lignin filtrate in the alkaline lignin filtrate temporary storage tank, adjust the pH value to 2.3, and pass it into a continuous centrifuge device for centrifugation to obtain high-purity lignin and filtrate, wherein the high-purity lignin is stored in the lignin temporary storage area, and the filtrate is stored in the filtrate temporary storage tank. The alkaline lignin filtrate feed flow rate is 37m³ / h, the lignin slag output is 1.8t / h, the filtrate discharge flow rate is 35m³ / h, and the centrifugal separation factor is 5000.

[0044] Furthermore, the method of the present invention further comprises: bleaching, drying and shaping the cellulose to obtain paper; or aging and yellowing the cellulose to obtain viscose fiber. Example 3

[0045] Based on Example 2, this example differs in that: The feed flow rate of the bagasse acid hydrolysis device in step 1 is 43m³ / h, the hydrolysis temperature is 116°C, and the discharge flow rate is 43m³ / h; In step 2, the feed flow rate of the first plate-frame filter press device is 43 m³ / h; the discharge flow rate of the xylose solution is 39 m³ / h, and the discharge rate of the hemicellulose-removed waste residue is 4.5 T / h; In step 3, the feed flow rate of the alkali extraction reaction device is 38.5 m³ / h, the reaction temperature is 103°C, and the discharge flow rate is 38.5 m³ / h; The feed flow rate of the alkali extraction mixed liquid of the second plate and frame filter press in step 4 is 38.5m³ / h, the cellulose residue discharge rate is 3.9t / h, and the lignin alkali liquid discharge flow rate is 34m³ / h; The lignin alkali liquor feed flow rate in step 6 is 34m³ / h, the lignin slag discharge rate is 1.7t / h, and the filtrate discharge flow rate is 32m³ / h. Example 4

[0046] Based on Example 2, this example differs in that: In step 1, the bagasse hydrolyzate includes 51 g / L xylose, 10.5 g / L sulfuric acid, and 134 g / L lignin and cellulose. Since the contents of various components in the bagasse fluctuate rather than being fixed values, the xylose content generated by hydrolysis will also fluctuate accordingly. In step 2, the xylose-containing hydrolyzate includes 51 g / L xylose and 10.5 g / L sodium sulfate; the hemicellulose-removed waste residue contains cellulose and lignin, and has a moisture content of 22%; In step 3, the alkaline extraction solution contains lignin at a concentration of 39 g / L and cellulose at a concentration of 93 g / L; In step 4, the cellulose solids have a moisture content of 22% and a purity of 95.4%, and the lignin solids have a moisture content of 21% and a purity of 97%. Example 5

[0047] Based on Example 2, this example differs in that: In step 1, the bagasse hydrolyzate includes 48 g / L xylose, 10.3 g / L sulfuric acid, and 131 g / L lignin and cellulose. Since the contents of various components in the bagasse fluctuate rather than being fixed values, the xylose content generated by hydrolysis will also fluctuate accordingly. In step 2, the xylose-containing hydrolyzate includes xylose at a concentration of 48 g / L and sodium sulfate at a concentration of 10.3 g / L; the hemicellulose-removed waste residue contains cellulose and lignin, and has a moisture content of 21%; In step 3, the alkaline extraction solution contains lignin at a concentration of 40 g / L and cellulose at a concentration of 91 g / L; In step 4, the cellulose solid moisture content is 23% and the purity is 96%, and the lignin solid moisture content is 22% and the purity is 97.5%. Example 6

[0048] Based on Example 2, this example differs in that: In step 1, the bagasse hydrolyzate includes 46 g / L xylose, 10.7 g / L sulfuric acid, and 136 g / L lignin and cellulose. Since the contents of various components in the bagasse fluctuate rather than being fixed values, the xylose content generated by hydrolysis will also fluctuate accordingly. In step 2, the xylose-containing hydrolyzate includes xylose at a concentration of 46 g / L and sodium sulfate at a concentration of 10.7 g / L; the hemicellulose-removed waste residue contains cellulose and lignin, and has a moisture content of 22%; In step 3, the alkaline extraction solution contains lignin at a concentration of 42 g / L and cellulose at a concentration of 95 g / L; In step 4, the cellulose solids have a moisture content of 20% and a purity of 96.1%, and the lignin solids have a moisture content of 21% and a purity of 97.3%. Example 7

[0049] Based on Example 2, this example differs in that: in step 6, the pH of the alkaline lignin filtrate after neutralization is 2.1. Example 8

[0050] Based on Example 2, this example differs in that: in step 6, the pH of the alkaline lignin filtrate after neutralization is 2.0. Example 9

[0051] Based on Example 2, this example differs in that: in step 6, the pH of the alkaline lignin filtrate after neutralization is 1.9. Example 10

[0052] This embodiment provides a method for comprehensive utilization of bagasse, using a comprehensive utilization device for bagasse, and the method comprises the following steps: Step 1: Using sugarcane bagasse crushed to 30 mesh and having a moisture content of 8%-10% as raw material, adding dilute sulfuric acid with an acidity of 0.9%-1.1% to the raw material, passing the raw material into a sugarcane bagasse acid hydrolysis device for hydrolysis at 116-120° C. for 2-2.5 hours, wherein the ratio of the raw material dry basis to the dilute sulfuric acid is 1 kg:5 L, the feed flow rate is 40-50 m³ / h, the discharge flow rate is 40-50 m³ / hm³ / h, and the sugarcane bagasse hydrolyzate is stored in a sugarcane bagasse hydrolyzate temporary storage tank; the xylose content in the xylose-containing hydrolyzate is 45-55 g / L, the lignin and cellulose content in the de-hemicellulose waste residue is 130-140 g / L, and the sulfuric acid content is 9-11 g / L; Step 2: Passing the bagasse hydrolyzate in the bagasse hydrolyzate temporary storage tank into a first plate and frame filter press device, which is automatically operated to obtain a xylose-containing hydrolyzate and a hemicellulose-removed waste residue; wherein the first plate and frame filter press device has an operating pressure of 40-45 bar, a feed temperature of 40-50°C, a feed flow rate of 45 m³ / h, a xylose-containing hydrolyzate discharge flow rate of 40 m³ / h, and a hemicellulose-removed waste residue discharge rate of 6 tonnes / h; the hemicellulose-removed waste residue contains lignin and cellulose, with a moisture content of 20-25%; the discharge rate is 5.5-6.5 tonnes / h on a dry basis, of which 1.7-1.9 tonnes / h on a dry basis and 4.0-4.5 tonnes / h on a dry basis; the xylose-containing hydrolyzate is stored in a xylose solution temporary storage tank, and the hemicellulose-removed waste residue is stored in a hemicellulose-removed waste residue temporary storage tank; Step 3: adding a sodium hydroxide solution having a concentration of 0.4% to the hemicellulose-removed waste residue, adding the solution to an alkali extraction reaction device, and extracting the solution at 100-105° C. for 2-2.1 hours to obtain an alkali extraction mixed solution; wherein the alkali extraction mixed solution is stored in an alkali extraction mixed solution temporary storage tank; the feed flow rate is 38-45 m³ / h, the discharge flow rate is 38-45 m³ / h, and the stirring rate of the alkali extraction reaction device is 2000 rpm; Step 4: Passing the alkali extraction mixture while hot into a second plate and frame filter press to obtain cellulose and alkaline lignin filtrate; wherein the second plate and frame filter press operates automatically, with an operating pressure of 40-45 bar, a feed temperature of 90-95°C, a feed flow rate of 38-45 m³ / h, a cellulose slag discharge of 4.2 t / h, an alkaline lignin filtrate discharge flow rate of 37 m³ / h, a cellulose moisture content of 20-25%, and a slag discharge of 4.0-4.5 t / h on a dry basis; the alkaline lignin filtrate includes lignin with a concentration of 35-45 g / L and a sodium hydroxide solution with a concentration of 38-42 g / L; the discharge flow rate is 30-40 m³ / h, the cellulose is stored in a cellulose temporary storage area, and the alkaline lignin filtrate is stored in an alkaline lignin filtrate temporary storage tank; Step 5: deacidifying and concentrating the xylose-containing hydrolyzate in the xylose solution temporary storage tank to obtain high-concentration xylose; Step 6: Add hydrochloric acid to the alkaline lignin filtrate in the alkaline lignin filtrate temporary storage tank, adjust the pH value to 2.3, and pass it into a continuous centrifuge for centrifugation to obtain high-purity lignin and filtrate, wherein the high-purity lignin is stored in the lignin temporary storage area and the filtrate is stored in the filtrate temporary storage tank; the alkaline lignin filtrate feed flow rate is 30-35m³ / h, the filtrate discharge flow rate is 27-31m³ / h, the high-purity lignin moisture content is 15%-20%, the discharge amount on a dry basis is 1.7-1.9t / h, and the centrifugal separation factor is 5000.

[0053] Furthermore, the method of the present invention further comprises: bleaching, drying and shaping the cellulose to obtain paper; or aging and yellowing the cellulose to obtain viscose fiber.

[0054] According to relevant standards, after testing, the xylose content of the xylose solution is greater than 45g / L; the xylose purity is greater than 82%; the organic acid is less than 0.1%; the chloride is less than 0.005%; the cellulose moisture is less than 25% and the purity is greater than 95%; the lignin moisture is less than 20% and the purity is greater than 98%; Example 11

[0055] A comprehensive utilization method of bagasse resources comprises the following steps: Hydrolysis: Add dilute sulfuric acid in a certain proportion to the crushed bagasse, pass it into a hydrolysis kettle, and hydrolyze it under certain conditions (see Table 1 below) to obtain a bagasse hydrolyzate (see Table 6 below); Filtration: The bagasse hydrolyzate is passed through the first plate and frame filter press (see Table 2 below) to produce a xylose-containing hydrolyzate (see Table 7 below) and a hemicellulose-free waste residue (see Table 8 below). The xylose-containing hydrolyzate can be further deacidified and concentrated to produce refined xylose. The hemicellulose-free waste residue is stored in a temporary storage area and then proceeds to the alkaline extraction process. Alkali extraction: The hemicellulose-removed waste residue is mixed with dilute alkali in a certain proportion, passed into a reactor, and extracted under certain conditions (as shown in Table 3 below) to obtain an alkaline extraction mixture (as shown in Table 9 below); Separation: The hot alkaline extraction mixture is passed through a second plate and frame filter press (see Table 4 below) to produce cellulose (see Table 10 below) and an alkaline lignin filtrate (see Table 11 below). The cellulose is stored in a temporary storage area and, after impurity removal, can be further used to produce high-value-added products. The alkaline lignin filtrate is stored in a temporary tank and, after pH adjustment and centrifugation (see Table 5 below), produces high-purity lignin (see Table 12 below).

[0056] Table 1 Control conditions for bagasse hydrolysis

[0057] Table 2 Control conditions of the first filter press

[0058] Table 3 Alkali extraction control conditions

[0059] Table 4 Second plate and frame filter press control conditions

[0060] Table 5 Continuous centrifugation control conditions

[0061] Table 6 Detection indicators in the solution after bagasse hydrolysis

[0062] Table 7 Xylose solution test indicators after plate and frame filter pressing

[0063] Table 8 Detection indexes of hemicellulose-removed waste residue after plate and frame filter pressing

[0064] Table 9 Detection indicators in the solution after alkaline extraction

[0065] Table 10 Cellulose detection indicators after plate and frame filter pressing

[0066] Table 11 Alkaline lignin filtrate test indicators after plate and frame filter pressing

[0067] Table 12 Lignin detection indicators after continuous centrifugation

[0068] In summary, the present invention separates hemicellulose, cellulose, and lignin from sugarcane bagasse. Specifically, the hemicellulose is first hydrolyzed under acidic conditions to convert it into xylose and a hemicellulose-free waste residue containing cellulose and lignin. The xylose can be used to produce xylose products. The hemicellulose-free waste residue is then reacted under alkaline conditions to separate the cellulose from the lignin. The separated lignin can be used to make stabilized lignin materials, and the separated cellulose can be used to make paper or viscose fibers. This method maximizes the development of sugarcane bagasse resources and significantly improves the overall economic and environmental benefits of the sugarcane sugar industry.

[0069] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A comprehensive utilization method of bagasse, characterized in that: The method comprises: The sugarcane bagasse is hydrolyzed under acidic conditions and filtered to obtain a hydrolyzate containing xylose and a hemicellulose-free waste residue; The hemicellulose-removed waste residue is extracted and filtered under alkaline conditions to obtain cellulose and alkaline lignin filtrate.

2. The comprehensive utilization method according to claim 1, characterized in that: The method further comprises: Deacidification and concentration of the xylose-containing hydrolyzate to obtain high-purity xylose; The pH value of the alkaline lignin filtrate is adjusted to 1.8-2.3 and centrifuged to obtain high-purity lignin.

3. The comprehensive utilization method according to claim 1, characterized in that: The method further comprises: Bleaching, drying, and forming the cellulose to obtain paper; or The cellulose is subjected to aging and yellowing treatment to obtain viscose fiber.

4. The comprehensive utilization method according to claim 1, characterized in that: The bagasse has a particle size of 20-40 meshes and a moisture content of 8%-10%.

5. The comprehensive utilization method according to claim 1, characterized in that: The acidic conditions include adding a sulfuric acid solution with an acidity of 0.9%-1.1%, a hydrolysis temperature of 116-120° C., and a hydrolysis time of 2-2.5 hours.

6. The comprehensive utilization method according to claim 5, characterized in that: The ratio of the dry basis of bagasse to the sulfuric acid solution is 0.5-1.5 kg: 2.5-7.5 L.

7. The comprehensive utilization method according to claim 1, characterized in that: The alkaline condition is to add sodium hydroxide solution, the concentration of the sodium hydroxide solution is 0.3%-0.5%, the extraction temperature is 100-105° C., and the extraction time is 2-2.1 hours.

8. The comprehensive utilization method according to claim 7, characterized in that: The ratio of the hemicellulose-removed waste residue to the sodium hydroxide solution is 0.5-1.5 kg: 2.5-7.5 L.

9. A comprehensive utilization device for bagasse, characterized in that: The equipment includes a bagasse acid hydrolysis device, a first plate-frame filter press device, an alkali extraction reaction device, and a second plate-frame filter press device; wherein, The bagasse acid hydrolysis device is a hydrolysis reactor, and the hydrolyzate discharge port of the hydrolysis reactor is connected to the hydrolyzate feed port of the first plate and frame filter press device; The alkali extraction reaction device is an alkali extraction reactor, and a stirring rod is installed in the alkali extraction reactor. The de-hemicellulose waste residue feed port of the alkali extraction reaction device is connected to the de-hemicellulose waste residue discharge port of the first plate and frame filter press device, and the alkali extraction mixed liquid discharge port of the alkali extraction reaction device is connected to the alkali extraction mixed liquid feed port of the second plate and frame filter press device.

10. Application of the comprehensive utilization method of bagasse according to any one of claims 1 to 8 in papermaking and viscose fiber.

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