A method and device for efficiently dismantling bagasse

Abstract

The present invention discloses a method and device for efficiently disassembling bagasse, which includes a disassembly reaction tank, an ethylene glycol heating tank, a heat exchanger, an acid precipitation tank, and a filter press. The method comprises the following steps: 1) crushing the bagasse; 2) mixing deionized water, sodium hydroxide, and ethylene glycol in a mass ratio of 0-21:1-12:78-88 to obtain an ethylene glycol-alkaline solvent; 3) mixing the ethylene glycol-alkaline solvent and bagasse in a certain proportion in a reaction tank, heating to 120-180°C and maintaining a constant temperature, and then introducing ethylene glycol heated to the same temperature as the reaction tank from the bottom of the tank to replace the extract; 4) sending the extract to an acid precipitation tank for acid precipitation, and then undergoing solid-liquid separation, obtaining lignin in the solid portion and sugar compounds and ethylene glycol in the liquid portion; 5) filtering the residue in the reaction tank to obtain a mixture of cellulose and hemicellulose. The present invention can achieve a high lignin removal rate and a high cellulose retention rate, and the device used can continuously replace the disassembly solvent to avoid the adsorption and deposition of lignin.

Description

Technical Field

[0001] The invention belongs to the technical field of resource utilization of organic solid waste, and in particular relates to a method and device for efficiently disassembling bagasse. Background Art

[0002] Bagasse is the largest byproduct of sugarcane sugar production. It features concentrated, uniform raw materials, stable composition, controllable quality, and simple collection, making it a high-quality raw material for converting lignocellulosic biomass. Therefore, to maximize the value of bagasse, it is necessary to first separate the raw materials into their components to obtain lignin of sufficient purity and quality, which can then be used as a platform compound for efficient conversion according to market demand in subsequent processes. To this end, there is an urgent need to develop a method and device for efficiently disassembling bagasse to achieve high lignin removal rates, recover high-purity lignin, and achieve high cellulose retention rates. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method and device for efficiently disassembling sugarcane bagasse, by which lignin with sufficient purity and quality can be obtained and the recovery rate of cellulose can be improved; the device can continuously replace the disassembly solvent to avoid the adsorption and deposition of lignin.

[0004] The present invention solves the above technical problems with the following technical solutions:

[0005] The present invention provides a method for efficiently dismantling bagasse, comprising the following steps:

[0006] (1) Crushing bagasse: crushing bagasse with a moisture content of 8-12% and screening bagasse with a length of 2-3 cm;

[0007] (2) Tempering the ethylene glycol-alkali solvent: mixing deionized water, sodium hydroxide, and ethylene glycol in a mass ratio of deionized water: sodium hydroxide: ethylene glycol = 0-21:1-12:78-88 to obtain an ethylene glycol-alkali solvent;

[0008] (3) High-temperature disassembly: the ethylene glycol-alkali solvent of step (2) and the sugarcane bagasse of step (1) are placed in a disassembly reaction tank at a ratio of 1000 mL of ethylene glycol-alkali solvent: 83.30 g of sugarcane bagasse, stirred and mixed, and heated to a disassembly temperature of 120 to 180° C. and maintained at a constant temperature. Then, ethylene glycol heated to the same temperature as the disassembly temperature in the reaction tank is introduced into the reaction tank from the bottom of the disassembly reaction tank to replace the extract. The replacement of the extract continues for 30 to 80 minutes and then the reaction is stopped;

[0009] (4) The extract of the disassembly reaction tank flows out from the top of the disassembly reaction tank and is sent to an acid precipitation tank for acid precipitation, and then mechanical solid-liquid separation is performed to obtain acid-insoluble lignin in the solid part and sugar compounds and ethylene glycol in the liquid part;

[0010] (5) The residue after the reaction in the dismantling reactor is removed and filtered through a filter press to obtain a mixture of cellulose and hemicellulose.

[0011] In the step (3), the ethylene glycol-alkali solvent and bagasse placed in the disassembly reaction tank are mechanically stirred at a rotation speed of 500 rpm for 10 minutes and then sealed and heated to 120-180°C.

[0012] In the step (3), ethylene glycol heated to the same temperature as the disassembly temperature in the reaction tank is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract.

[0013] In the step (4), the extract flowing into the acid precipitation tank is adjusted to a pH value of 4.5 using sulfuric acid and stirred at a stirring speed of 800 rpm at 25° C. for 15 minutes. After the stirring is completed, the pH value of the extract is adjusted to 3.0, and then heated to 65° C. and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin, and the recovered ethylene glycol is subjected to reduced pressure distillation to recover the residual sugar compounds and evaporated ethylene glycol.

[0014] In the step (5), the specific operation of the filter press is: the disassembled residue is filtered by the filter press, the liquid phase after the filtration flows into the acid precipitation tank, and the solid phase after the filtration is washed to obtain a cellulose and hemicellulose mixture.

[0015] In the step (4), the mechanical separation is gravity sedimentation, centrifugal separation or plate and frame filter press.

[0016] The invention discloses a device for efficiently disassembling bagasse. The device comprises a disassembling reaction tank, an ethylene glycol heating tank, a heat exchanger, an acid precipitation tank and a filter press. The disassembling reaction tank is provided with a feeding port for an ethylene glycol-alkali solvent and bagasse, a bottom inlet of the disassembling reaction tank is connected to an outlet of the ethylene glycol heating tank via a pipeline, the bottom outlet of the disassembling reaction tank is connected to the filter press, a top outlet of the disassembling reaction tank is connected to a hot liquid inlet end of the heat exchanger via a pipeline, the hot liquid outlet end of the heat exchanger is connected to an inlet of the acid precipitation tank, a cold liquid inlet end of the heat exchanger is connected to a normal-temperature ethylene glycol delivery pipe, the cold liquid outlet end of the heat exchanger is connected to the inlet of the ethylene glycol heating tank, and a filtrate collecting chamber of the filter press is connected to the hot liquid inlet end of the heat exchanger via a pipeline or is directly connected to the acid precipitation tank.

[0017] The feeding port of the ethylene glycol-alkali solvent is arranged at the lower part of the disassembly reaction tank, and the feeding port of the bagasse is arranged at the top of the disassembly reaction tank.

[0018] The method and device for efficiently disassembling bagasse of the present invention have the following beneficial effects:

[0019] 1) The present invention utilizes ethylene glycol to decompose lignocellulosic biomass, thereby achieving a high lignin removal rate and recovering high-purity lignin, while also obtaining a high cellulose retention rate.

[0020] 2) The device used in the present invention can continuously replace the disassembly solvent to avoid the adsorption and deposition of lignin.

[0021] 3) The present invention can degrade the ether-ester bonds between lignin and carbohydrates, weakening the repolymerization reaction between lignin monomers and hydroxycinnamic acid. The etherification reaction between the degraded lignin monomers and ethylene glycol can further protect the β-O-4 bonds in lignin and introduce more active hydroxyl groups, thereby retaining the characteristic component of lignin as an intermediate macromolecule for conversion to end products.

[0022] 4) The present invention takes the extraction rate and activity of lignin as the primary goal, ensuring that the three major components after separation can be efficiently converted into end products. It has important practical significance for the deployment of the strategic material-sucrose industry chain and the diversified and high-value development of sugarcane bagasse. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The figure is a schematic structural diagram of the device for efficiently disassembling bagasse according to the present invention.

[0024] Figure 2 This is the HSQC spectrum of the recovered and purified lignin in Example 9 of the present invention.

[0025] Figure 1 Middle: Disassemble the reaction tank 1, ethylene glycol heating tank 2, heat exchanger 3, acid precipitation tank 4, filter press 5, ethylene glycol-alkali solvent feed port 5-1, and bagasse feed port 5-2. DETAILED DESCRIPTION

[0026] The method and device of the present invention are further explained and illustrated below in conjunction with specific embodiments. It should be noted that the following embodiments are not intended to limit the scope of rights of the present invention.

[0027] like Figure 1As shown, the device for efficiently disassembling bagasse of the present invention includes a disassembling reaction tank 1, an ethylene glycol heating tank 2, a heat exchanger 3, an acid precipitation tank 4 and a filter press 5. The lower part of the disassembling reaction tank 1 is provided with an ethylene glycol-alkali solvent feed port 5-1, the top of the disassembling reaction tank 1 is provided with a bagasse feeding port 5-2, the bottom inlet of the disassembling reaction tank 1 is connected to the outlet of the ethylene glycol heating tank 2 via a pipeline, the bottom outlet of the disassembling reaction tank 1 is connected to the filter press 5, the top outlet of the disassembling reaction tank 1 is connected to the hot liquid inlet end of the heat exchanger 3 via a pipeline, the hot liquid outlet end of the heat exchanger 3 is connected to the inlet of the acid precipitation tank 4, the cold liquid inlet end of the heat exchanger 3 is connected to the normal temperature ethylene glycol delivery pipe, the cold liquid outlet end of the heat exchanger 3 is connected to the inlet of the ethylene glycol heating tank 2, and the filtrate collecting chamber of the filter press 5 is connected to the hot liquid inlet end of the heat exchanger 3 via a pipeline or directly connected to the acid precipitation tank 4.

[0028] The present invention provides a method for efficiently dismantling bagasse, see Figure 1 , including the following steps:

[0029] (1) Crushing bagasse: crush and screen bagasse with a moisture content of 8-12%, remove large and small bagasse, and screen bagasse with a length of 2-3 cm.

[0030] (2) Tempering the ethylene glycol-alkali solvent: Deionized water, sodium hydroxide, and ethylene glycol are mixed in a mass ratio of deionized water: sodium hydroxide: ethylene glycol = 0-21: 1-12: 78-88 to obtain an ethylene glycol-alkali solvent.

[0031] (3) High-temperature disassembly: The ethylene glycol-alkali solvent of step (2) and the sugarcane bagasse of step (1) are placed into the disassembly reaction tank 1 through the ethylene glycol-alkali solvent feed port 5-1 and the sugarcane bagasse feeding port 5-2 at a ratio of 1000 mL ethylene glycol-alkali solvent: 83.30 g sugarcane bagasse, respectively. After mechanical stirring at a speed of 500 rpm for 10 minutes, the mixture is sealed and heated to a disassembly temperature of 120-180° C. and maintained at a constant temperature. Then, ethylene glycol heated to the same temperature as the disassembly temperature in the reaction tank is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract. The replacement of the extract continues for 30-80 minutes and then the reaction is stopped.

[0032] (4) The extract of the disassembly reaction tank flows out from the top of the disassembly reaction tank and is sent to the acid precipitation tank 4 through the heat exchanger 3 for acid precipitation. After mechanical solid-liquid separation, the solid part obtains acid-insoluble lignin, and the liquid part obtains sugar compounds and ethylene glycol. The specific operation is: the extract flowing into the acid precipitation tank is adjusted to pH 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25 ° C for 15 minutes. After the stirring is completed, the pH value of the extract is adjusted to 3.0, and then heated to 65 ° C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin, and the recovered ethylene glycol is subjected to reduced pressure distillation to recover the residual sugar compounds and evaporated ethylene glycol. The mechanical separation is gravity sedimentation, centrifugal separation, plate and frame filter press, etc.

[0033] (5) The residue after the reaction in the disassembly reaction tank is removed and filtered through a filter press 5 to obtain a cellulose and hemicellulose mixture. The specific operation of the filter press is as follows: the disassembly residue is filtered through a filter press, and the liquid phase after filtration flows into the acid precipitation tank 4 or flows into the acid precipitation tank 4 after passing through a heat exchanger 3, and the solid phase after filtration is washed to obtain a cellulose and hemicellulose mixture.

[0034] The present invention utilizes a heat exchanger 3 and an ethylene glycol heating tank 2 to heat ethylene glycol. Specifically, the steps are as follows: ethylene glycol at room temperature is introduced into the outside of a pipe in the heat exchanger 3 through a pipe, preheated after heat exchange and then enters the ethylene glycol heating tank 2; the ethylene glycol heating tank 2 is opened and the ethylene glycol is heated to a temperature equal to the disassembly temperature, then kept warm and the outlet valve is closed; the extract in the disassembly reaction tank 1 flows out from the upper part of the disassembly reaction tank, exchanges heat with ethylene glycol through an internal pipe of the heat exchanger 3, and then flows into the acid precipitation tank 4.

[0035] Example 1

[0036] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0037] (1) Crushing bagasse: crush the cleaned bagasse, screen the bagasse with a length of 2 to 3 cm, and determine its moisture content to be 10%.

[0038] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol were fully mixed in a mass ratio of 10:12:78 to obtain an ethylene glycol-alkali solvent.

[0039] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 180°C, and the temperature is maintained constant, and then 180°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 50 minutes and then stopped.

[0040] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0041] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0042] Results: The bagasse treated by the method of the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 97.90% and a cellulose recovery rate of 58.26%.

[0043] Example 2

[0044] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0045] (1) Crushing bagasse: Crushing the washed bagasse, screening the bagasse with a length of 2 to 3 cm, and measuring the moisture content thereof to be 11%.

[0046] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol were fully mixed in a mass ratio of 3:12:85 to obtain an ethylene glycol-alkali solvent.

[0047] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 140°C, and the temperature is maintained constant, and then 140°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 80 minutes and then stopped.

[0048] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0049] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0050] Results: The bagasse treated by the method of the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 95.27% and a cellulose recovery rate of 76.12%.

[0051] Example 3

[0052] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0053] (1) Crushing bagasse: crush the clean bagasse, screen the bagasse with a length of 2 to 3 cm, and measure its moisture content to be 8%.

[0054] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol were fully mixed in a mass ratio of 21:1:78 to obtain an ethylene glycol-alkali solvent.

[0055] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 120°C, and the temperature is maintained constant, and then 120°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 30 minutes and then stopped.

[0056] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0057] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0058] Results: The bagasse treated by the method of the present invention had a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 87.47% and a cellulose recovery rate of 81.11%.

[0059] Example 4

[0060] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0061] (1) Crushing bagasse: crush the clean bagasse, screen the bagasse with a length of 2 to 3 cm, and measure its moisture content to be 8%.

[0062] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol were fully mixed in a mass ratio of 7:8:85 to obtain an ethylene glycol-alkali solvent.

[0063] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 120°C, and the temperature is maintained constant, and then 120°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 50 minutes and then stopped.

[0064] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0065] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0066] Results: The bagasse treated by the method of the present invention had a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 89.30% and a cellulose recovery rate of 84.96%.

[0067] Example 5

[0068] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0069] (1) Crushing bagasse: crush the clean bagasse, screen the bagasse with a length of 2 to 3 cm, and measure its moisture content to find that it is 12%.

[0070] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol are fully mixed in a mass ratio of 13:5:82 to obtain an ethylene glycol-alkali solvent.

[0071] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 120°C, and the temperature is maintained constant, and then 120°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 80 minutes and then stopped.

[0072] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0073] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0074] Results: The bagasse treated by the method of the present invention had a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 89.84% and a cellulose recovery rate of 82.75%.

[0075] Example 6

[0076] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0077] (1) Crushing bagasse: crush the cleaned bagasse, screen the bagasse with a length of 2 to 3 cm, and determine its moisture content to be 10%.

[0078] (2) Tempering the ethylene glycol-alkali solvent: Sodium hydroxide and ethylene glycol are fully mixed in a mass ratio of 12:88 to obtain an ethylene glycol-alkali solvent.

[0079] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 120°C, and the temperature is maintained constant, and then 120°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 70 minutes and then stopped.

[0080] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0081] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0082] Results: The bagasse treated by the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 92.85% and a cellulose recovery rate of 80.82%.

[0083] Example 7

[0084] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0085] (1) Crushing bagasse: crush the washed bagasse, screen the bagasse with a length of 2 to 3 cm, and measure its moisture content to be 9%.

[0086] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol are fully mixed in a mass ratio of 10:5:85 to obtain an ethylene glycol-alkali solvent.

[0087] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 180°C, and the temperature is maintained constant, and then 180°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 30 minutes and then stopped.

[0088] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0089] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0090] Results: The bagasse treated by the method of the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 97.99% and a cellulose recovery rate of 70.74%.

[0091] Example 8

[0092] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0093] (1) Crushing bagasse: crush the washed bagasse, screen the bagasse with a length of 2 to 3 cm, and measure its moisture content to be 9%.

[0094] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol are fully mixed in a mass ratio of 17:5:78 to obtain an ethylene glycol-alkali solvent.

[0095] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 140°C, and the temperature is maintained constant, and then 140°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 70 minutes and then stopped.

[0096] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0097] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0098] Results: The bagasse treated by the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 95.19% and a cellulose recovery rate of 81.67%.

[0099] Example 9

[0100] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0101] (1) Crushing bagasse: crush the cleaned bagasse, screen the bagasse with a length of 2 to 3 cm, and determine its moisture content to be 10%.

[0102] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol are fully mixed in a mass ratio of 14:1:85 to obtain an ethylene glycol-alkali solvent.

[0103] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 160°C, and the temperature is maintained constant, and then 160°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 70 minutes and then stopped.

[0104] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0105] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0106] Results: The bagasse treated by the method of the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 95.85% and a cellulose recovery rate of 82.64%.

[0107] Example 10

[0108] The operating method of the present invention for efficiently dismantling bagasse is as follows:

[0109] (1) Crushing bagasse: crush the cleaned bagasse, screen the bagasse with a length of 2 to 3 cm, and determine its moisture content to be 10%.

[0110] (2) Tempering the ethylene glycol-alkali solvent: deionized water, sodium hydroxide, and ethylene glycol are fully mixed in a mass ratio of 14:8:78 to obtain an ethylene glycol-alkali solvent.

[0111] (3) The ethylene glycol-alkali solvent of step (2) and the bagasse treated in step (1) are placed in a disassembly reaction tank for mixing and high-temperature depolymerization to obtain an extract. The specific operation is as follows: 1000 mL of ethylene glycol-alkali solvent and 83.30 g of bagasse are stirred at a stirring speed of 500 rpm for 10 minutes to be fully mixed, the disassembly reaction tank is opened and heated to a disassembly temperature of 160°C, and the temperature is maintained constant, and then 160°C ethylene glycol is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract, and the liquid is continued to react for 80 minutes and then stopped.

[0112] (4) The extract flows out from the upper part of the disassembly reaction tank, exchanges heat with the ethylene glycol outside the pipe through the internal pipe of the heat exchanger, and then flows into the acid precipitation tank. The extract in the acid precipitation tank is acid precipitated to extract lignin. The specific operation is as follows: the pH value of the extract in the acid precipitation tank is adjusted to 4.5 with sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is further adjusted to 3.0 and heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin; the recovered ethylene glycol is subjected to reduced pressure distillation and the residual sugar compounds and evaporated ethylene glycol are recovered.

[0113] (5) The residue after the reaction in the disassembly reaction tank is removed, and the residue is separated into solid and liquid using a filter press. The specific operation is as follows: the residue in the disassembly reaction tank is removed from the discharge port of the disassembly reaction tank and filtered by the filter press. The liquid phase after filtration flows into the internal pipe of the heat exchanger to exchange heat with ethylene glycol and then flows into the acid precipitation tank. The solid portion after filtration is washed to obtain a mixture of cellulose and hemicellulose.

[0114] Results: The bagasse treated by the method of the present invention has a high lignin removal rate and a high cellulose recovery rate, specifically, a lignin removal rate of 97.30% and a cellulose recovery rate of 83.74%.

[0115] The experimental results of Examples 1-10 of the method of the present invention are compared with other pretreatment results, as shown in Table 1:

[0116] Table 1 Comparison of example results

[0117]

[0118] As shown in Table 1, compared with other methods, the method of the present invention can achieve a high removal rate of lignin and a high retention rate of cellulose, and is a method for efficiently degrading bagasse.

[0119] Figure 2 This is the HSQC spectrum of the purified lignin recovered in Example 9 of the present invention. Figure 2It was found that the characteristic signals of methoxy (OCH3), β-O-4 aryl ether (A), phenyl coumarin (B), and resin alcohol (C) can be observed in the side chain region (δC / δH 50-90 / 2.5-5.5ppm) of the 2D HSQC spectrum of the lignin sample obtained in Example 9; in the aromatic region (δC / δH90-150 / 5.5-8.0ppm), G, S, H units and other structures have obvious signal characteristics. The characteristic signals in this two-dimensional spectrum are relatively rich and strong, and A can be observed in the side chain region. γ 、A α 、A β (G / H), A β The peak signal of (S) indicates that the lignin sample has a high content of β-O-4 aryl ether bonds, which is consistent with the role of ethylene glycol in protecting the β-O-4 linkages in lignin. Hydrogenation can be used to break these linkages, increase the phenolic hydroxyl content, and thus improve the activity of lignin.

[0120] The results show that the method of the present invention has a good effect on the removal and recovery of each component, which is greatly beneficial to the high-value utilization of bagasse. At the same time, it can be seen from the 2D HSQC spectrum that the recovered lignin contains more β-O-4 ether bonds, which can retain more active hydroxyl groups for lignin and obtain an excellent lignin utilization precursor. In the ethylene glycol-alkali pretreatment system of the present invention, as the temperature of the reaction system increases, the alkali and ethylene glycol cooperate with each other, which can not only promote the removal of lignin and increase the porous structure of bagasse, but also prevent the loss of carbohydrates and reduce the production of toxic by-products. Compared with other pretreatments, the method of the present invention can remove a large amount of lignin and recover lignin with better activity, while also enhancing the enzymatic saccharification effect of cellulose.

Claims

1. A method for efficiently dismantling bagasse, characterized in that: The steps are as follows: (1) Bagasse crushing: crush bagasse with a moisture content of 8-12% and select bagasse with a length of 2-3 cm; (2) Tempering ethylene glycol-alkali solvent: mixing deionized water, sodium hydroxide and ethylene glycol in a mass ratio of deionized water: sodium hydroxide: ethylene glycol = 0-21:1-12:78-88 to obtain ethylene glycol-alkali solvent; (3) High-temperature disassembly: The ethylene glycol-alkali solvent of step (2) and the sugarcane bagasse of step (1) are placed in a disassembly reaction tank at a ratio of 1000 mL ethylene glycol-alkali solvent: 83.30 g sugarcane bagasse, stirred and mixed, and heated to a disassembly temperature of 120-180°C and kept at a constant temperature. Then, ethylene glycol heated to the same temperature as the disassembly temperature in the reaction tank is introduced into the reaction tank from the bottom of the disassembly reaction tank to replace the extract. The replacement of the extract continues for 30-80 minutes and then the reaction is stopped; (4) The extract of the disassembly reaction tank flows out from the top of the disassembly reaction tank and is sent to the acid precipitation tank for acid precipitation. Then, the solid-liquid separation is carried out mechanically, and acid-insoluble lignin is obtained in the solid part, and sugar compounds and ethylene glycol are obtained in the liquid part; (5) The residue after the reaction in the disassembled reactor is removed and filtered through a filter press to obtain a mixture of cellulose and hemicellulose.

2. The method for efficiently dismantling bagasse according to claim 1, wherein: In the step (3), the ethylene glycol-alkali solvent and bagasse placed in the disassembly reaction tank are mechanically stirred at a speed of 500 rpm for 10 minutes and then sealed and heated to 120-180°C.

3. The method for efficiently dismantling bagasse according to claim 1, wherein: In the step (3), ethylene glycol heated to the same temperature as the disassembly temperature in the reaction tank is introduced into the reaction tank from the bottom of the disassembly reaction tank at a flow rate of 100 mL / min to replace the extract.

4. The method for efficiently dismantling bagasse according to claim 1, wherein: In the step (4), the extract flowing into the acid precipitation tank is adjusted to a pH value of 4.5 using sulfuric acid and stirred at a stirring speed of 800 rpm at 25°C for 15 minutes. After the stirring is completed, the pH value of the extract is adjusted to 3.0, and then heated to 65°C and stirred at a stirring speed of 800 rpm for 30 minutes for acid precipitation. After the lignin is completely precipitated, the acid precipitation liquid is centrifuged to obtain lignin, and the recovered ethylene glycol is subjected to reduced pressure distillation to recover the residual sugar compounds and evaporated ethylene glycol.

5. The method for efficiently dismantling bagasse according to claim 1, wherein: In the step (5), the specific operation of the filter press is: the disassembled residue is filtered by the filter press, the liquid phase after the filtration flows into the acid precipitation tank, and the solid phase after the filtration is washed to obtain a cellulose and hemicellulose mixture.

6. The method for efficiently dismantling bagasse according to claim 1, characterized in that: In the step (4), the mechanical separation is gravity sedimentation, centrifugal separation or plate and frame filter press.

Images