Preparation method of bamboo biomass sugar

Abstract

The invention relates to a preparation method of bamboo biomass sugar, which overcomes the defect that bamboo hemicelluloses cannot be fully utilized in the prior art, and comprises the following steps: by taking bamboo as a raw material, preparing and pretreating the bamboo, and then hydrolyzing the hemicelluloses in the bamboo raw material through a sugar extraction step, thereby obtaining the bamboo biomass sugar. The preparation method comprises the following steps: firstly, preparing the bamboo biomass sugar solution, then sequentially carrying out seven steps of neutralization, concentration and purification, re-concentration and chromatographic separation to efficiently prepare the bamboo biomass sugar solution which comprises 5-50% of xylooligosaccharide and 30-70% of xylose, and the purities of the two components are both 90% or above. Besides, according to the preparation method of the bamboo biomass sugar and the bamboo obtained after biomass sugar extraction, the bamboo can be used for producing dissolving pulp and fluff pulp, more additional values can be generated, the method is more significant for improving the comprehensive value of bamboo resources, a brand new preparation path is developed for the biomass sugar, and meanwhile the barrier of low-value utilization of the bamboo is broken through.

Description

Technical Field

[0001] The present application relates to the field of biomass sugar preparation, and specifically to a method for preparing bamboo biomass sugar. Background Art

[0002] Biomass is the only renewable carbon resource in nature, and biomass sugar is a cheap and readily available chemical raw material, including cellulose and hemicellulose in woody biomass, as well as derived sugars such as starch, xylose, fructose, glucose, and sucrose. The further conversion of derived sugars into energy (fuel ethanol, biodiesel, hydrogen, etc.) and chemical platform chemicals (organic acids, organic alcohols, esters, etc.) is an ideal way to efficiently utilize biomass resources.

[0003] Currently, plant hemicellulose extracts on the market are primarily used to produce xylose, xylitol, or xylooligosaccharides, primarily using corncobs and bagasse as raw materials. These extracts have mature industrial production technologies and a mature market. While bamboo resources, a key raw material for pulping and papermaking, have been widely utilized for their cellulose and lignin, hemicellulose remains largely unused and is typically incinerated with black liquor, failing to generate significant economic value.

[0004] The hemicellulose hydrolysis products in bamboo contain dual components of xylose and oligoxylose, both of which are high-value-added products and important components of bamboo biomass sugar. Therefore, it is imperative to develop a method for preparing biomass sugar using hemicellulose in bamboo. Summary of the Invention

[0005] In view of the above deficiencies in the prior art, the present application provides a method for preparing biomass sugar using bamboo as raw material, which opens up another way to obtain biomass sugar and improves the comprehensive utilization value of bamboo resources.

[0006] The present application provides a method for preparing bamboo biomass sugar, comprising the following steps: (1) Material preparation: bamboo is sliced ​​and / or made into bamboo chips and bamboo powder, and then washed with water to obtain bamboo raw materials; (2) Pretreatment: adding a pretreatment medium to the bamboo raw material for pretreatment; The pretreatment medium contains 0.05%-0.12% sulfuric acid, and the pretreatment is carried out for 0.5-2 hours; (3) Sugar extraction: 3a was added to the pretreated bamboo raw material hydrolysis medium, the bamboo raw material hemicellulose hydrolysis reaction, cooling the hydrolyzate after the discharge reaction; The hydrolysis medium is 0.5%-3% sulfuric acid, the hydrolysis temperature is 100-120°C, and the hydrolysis time is 1-4 hours; 3b adding water to cycle the washing reaction residue to obtain a sugar recovery liquid; 3c. mixing the hydrolyzate and the sugar recovery solution in a ratio of 1:1 to 1:2 to obtain a mixed solution; (4) Neutralization: 4a under stirring conditions to the mixture was slowly added calcium carbonate slurry for neutralization reaction, the reaction temperature 75-85 ℃, the reaction time 0.5-1 hour to obtain a neutralized solution; 4b the neutralized solution was subjected to solid-liquid separation, and the calcium sulfate crystals were filtered out to obtain a clear solution; (5) Concentration and purification: 5a. The supernatant was pumped into a membrane device for desalination and concentration to obtain a concentrate; 5b under stirring conditions to the concentrate was added activated carbon for decolorization, and the temperature was raised to 70-80 ℃, heat for 0.5-1 hours; 5c The decolorized concentrate was subjected to solid-liquid separation, and the activated carbon sludge was filtered out to obtain a decolorized liquid; 5d the decolorized liquid was pumped into an ion exchange column for ion exchange purification to obtain a bamboo biomass sugar solution; (6) re-concentrating: concentrating the bamboo biomass sugar solution to a concentration of 55%-65% to obtain a concentrated syrup; (7) Chromatographic separation: The concentrated syrup is separated by a continuous chromatographic separation device to obtain oligoxylose liquid and xylose liquid with a concentration of 30%-50%.

[0007] As a further improvement to the above scheme, the preparation method also includes the steps of concentrating the xylooligosaccharide liquid and xylose liquid respectively, and drying the concentrated xylooligosaccharide liquid and xylose liquid respectively through a high-pressure pump into a spray dryer to obtain powdered xylooligosaccharides and powdered xylose.

[0008] As a further improvement to the above scheme, the hydrolyzed liquid vapor produced by the hydrolysis reaction in step 3a is fed into a jet condenser for condensation, and the produced condensate is used for the circulating washing reaction residue in step 3b.

[0009] As a further improvement to the above scheme, in step 4a, the pH of the neutralization solution is controlled to be 3.5-4; Alternatively, in step 5b, the amount of activated carbon is controlled to be 10%-30% of the total solids.

[0010] As a further improvement to the above solution, after step 5c, the decolorized liquid is pumped into a membrane filter device for desalination and concentration.

[0011] As a further improvement to the above solution, the filter membrane equipment uses a ceramic nanofiltration membrane, and the molecular weight cutoff value of the filter membrane is 150-200Da.

[0012] As a further improvement to the above solution, in step 5d, the ion exchange column includes at least one cation exchange column and at least one anion exchange column.

[0013] As a further improvement to the above scheme, step (6) includes: 6a The bamboo biomass sugar solution was pumped into the membrane device to concentrate to obtain a concentration of 20% -22% bamboo biomass sugar concentrate; 6b. The bamboo biomass sugar concentrate was pumped into a plate evaporator and concentrated to 55%-65% to obtain the concentrated syrup.

[0014] As a further improvement to the above scheme, the permeate in steps 5a and 6a and the evaporated condensate in step 6b are all sent to the pretreatment medium tank for use in the bamboo raw material pretreatment in step (2).

[0015] As a further improvement to the above scheme, in step (7), the concentrated syrup is separated by using a SSMB sequential simulated moving bed.

[0016] The above-mentioned technical solution of the present application has the following advantages over the existing technology: the preparation method of bamboo biomass sugar provided by the present application overcomes the defect in the existing technology that bamboo hemicellulose is not fully utilized. Bamboo is used as raw material. After preparation and pretreatment, the hemicellulose in the bamboo raw material is hydrolyzed through a sugar extraction step, and then seven steps of neutralization, concentration and purification, re-concentration and chromatographic separation are sequentially performed to efficiently prepare a bamboo biomass sugar solution, which contains 5%-50% of oligoxylose and 30%-70% of xylose, and the purity of the two components is above 90%. DETAILED DESCRIPTION

[0017] The present application is described in detail below so that the advantages and features of the present application can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present application.

[0018] The present application provides a method for preparing bamboo biomass sugar, aiming to solve the problem that bamboo hemicellulose is not fully utilized in the existing technology, improve the comprehensive utilization value of bamboo resources, and at the same time open up a new preparation path for biomass sugar.

[0019] The method for preparing bamboo biomass sugar comprises the following steps: (1) Material preparation: bamboo is sliced ​​and / or made into bamboo chips and bamboo powder, and then washed with water to obtain bamboo raw materials.

[0020] Specifically, the bamboo material is processed from raw bamboo into bamboo slices with a length of 3-5 cm and a width of 1-2 cm, or processed into smaller-sized bamboo chips and bamboo powder, and then washed by at least two series-connected washing machines to remove impurities.

[0021] The washing water of washed bamboo raw materials is recycled, purified and reused.

[0022] (2) Pretreatment: The bamboo raw materials cleaned by the water washing machine are sent to the hydrolysis reaction tank via a spiral conveyor, and a pretreatment medium is added to the bamboo raw materials for pretreatment.

[0023] The pretreatment medium contains 0.05%-0.12% sulfuric acid, and the pretreatment medium is made to completely infiltrate the bamboo raw material, and the pretreatment is carried out for 0.5-2 hours.

[0024] After the pretreatment is completed, the pretreatment liquid is pumped out to the pretreatment liquid tank and enters the middle water for purification and reuse after pH adjustment.

[0025] Furthermore, the hydrolysis reaction tanks can be provided in one group or in two or more groups. The hydrolysis can be performed simultaneously using multiple groups of hydrolysis reaction tanks to increase production capacity and improve production efficiency.

[0026] (3) Sugar extraction: 3a. Adding a hydrolysis medium to the pretreated bamboo raw material in the hydrolysis reaction tank, so that the hydrolysis medium completely infiltrates the bamboo raw material, and the hemicellulose in the bamboo raw material undergoes a hydrolysis reaction.

[0027] The solid-liquid volume ratio is 1:2-1:4, the hydrolysis medium is 0.5%-3% sulfuric acid, the hydrolysis temperature is 100-120° C., and the hydrolysis time is 1-4 hours.

[0028] The hydrolyzed liquid after the reaction is cooled and then discharged into the hydrolyzed liquid tank. Specifically, the hydrolyzed liquid is first cooled to 70-80° C. by heat exchange and then discharged into the hydrolyzed liquid tank.

[0029] 3b. Add water to circulate and wash the reaction residue to obtain a sugar recovery liquid, which is then pumped out to a sugar recovery liquid tank.

[0030] In this step, the volume of the circulating washing water is controlled to be 4-8 times the volume of the solid matter.

[0031] In step 3a, the hydrolyzed liquid vapor generated by the hydrolysis reaction is passed into a jet condenser for condensation, and the generated condensate is sent to a sugar recovery medium tank for use in circulating and washing the reaction residue in this step to collect as much sugar generated by the hydrolysis reaction as possible.

[0032] 3c. In a combined hydrolyzate tank, the hydrolyzate and the sugar recovery solution are mixed in a mass ratio of 1:1 to 1:2 to obtain a mixed solution.

[0033] In the above-mentioned pretreatment step and sugar extraction step, the pretreatment liquid, the hydrolyzed liquid, and the sugar recovery liquid are recovered / collected separately, and the liquids from each stage will not cross each other, thereby ensuring the stable quality of the products in each subsequent process.

[0034] (4) Neutralization: 4a. The mixed solution in the combined hydrolyzed liquid tank was pumped to a neutralization tank, and calcium carbonate slurry was slowly added to the mixed solution under stirring conditions for neutralization reaction. The reaction temperature was 75-85°C and the reaction time was 0.5-1 hour to obtain a neutralized solution.

[0035] Furthermore, in this step, steam is introduced into the neutralization tank to raise the temperature to 75-85°C.

[0036] In this step, the pH of the neutralization solution is controlled to be 3.5-4.

[0037] 4b. The neutralized liquid is pumped into a plate and frame filter for solid-liquid separation to filter out the calcium sulfate crystals to obtain a clear liquid, which is then fed into a neutralization tank.

[0038] Furthermore, the plate and frame filter is a closed plate and frame filter, which prevents steam from escaping during the solid-liquid separation process and protects the clear liquid from contamination, thereby improving production cleanliness.

[0039] (5) Concentration and purification: 5a. The clear liquid from the first neutralization tank is pumped into a membrane device for desalination and concentration to obtain a concentrate, which is fed into the second neutralization tank and the permeate is fed into the pretreatment medium tank.

[0040] The pretreatment medium tank is used to store the pretreatment medium for use in the bamboo raw material pretreatment section.

[0041] Furthermore, the membrane filter device uses a ceramic nanofiltration membrane to overcome the disadvantage of using a conventional synthetic material membrane, which requires cooling the clear liquid to below 50° C., thereby improving the concentration efficiency of the clear liquid.

[0042] Furthermore, the molecular weight cut-off value of the filter membrane is 150-200 Da, so that impurities such as salts with molecular weights below this range in the clear liquid are discharged with the permeate.

[0043] The molecular weight cut-off value refers to the lower limit of the molecular weight of molecules that can be completely retained during the membrane filtration process, and the molecular weight cut-off value is usually expressed in Da (Dalton).

[0044] 5b. The concentrate was pumped from the second stage neutralization tank into the decolorization tank, activated carbon was added to the concentrate under stirring conditions for decolorization, and the temperature was raised to 70-80 ℃ through steam and kept warm for 0.5-1 hour; Furthermore, in this step, steam is introduced into the decolorization tank to raise the temperature to 70-80°C.

[0045] Furthermore, the activated carbon is wet powdered activated carbon or slurry activated carbon, which increases its contact area with the concentrated liquid compared to solid activated carbon, thereby improving the decolorization efficiency and effect.

[0046] Furthermore, the amount of activated carbon is controlled to be 10%-30% of the total solids.

[0047] 5c. The decolorized mixed liquid is pumped into a plate and frame filter for solid-liquid separation to filter out the activated carbon sludge powder, and the decolorized liquid is sent to the decolorization liquid tank.

[0048] Furthermore, the plate and frame filter is a closed plate and frame filter, which prevents steam from emitting during the solid-liquid separation process and protects the decolorized liquid from contamination, thereby improving production cleanliness.

[0049] Furthermore, the transmittance of the decolorized liquid after solid-liquid separation is controlled to be above 80%, and the activated carbon sludge powder is sent to the boiler for combustion and reuse after secondary recycling.

[0050] In one embodiment, the method for preparing bamboo biomass sugar further comprises the step of pumping the decolorized liquid from the decolorized liquid tank into a membrane filter device for desalination and concentration, so as to further reduce the load of the subsequent ion exchange purification process.

[0051] In this embodiment, the permeate of the decolorized liquid after desalination and concentration is sent to the pretreatment medium tank.

[0052] Furthermore, the membrane filter equipment uses a ceramic nanofiltration membrane with a molecular weight cutoff value of 150-200Da to further filter out salt impurities in the decolorant and increase the concentration of the decolorant. The ceramic nanofiltration membrane overcomes the disadvantage of using conventional synthetic material membranes that the decolorant needs to be cooled to below 50°C, thereby improving the concentration efficiency of the decolorant.

[0053] 5d. The decolorized liquid was pumped into an ion exchange column for ion exchange purification to obtain a bamboo biomass sugar solution, which was then fed into a sugar solution storage tank.

[0054] This step removes the residual ash salt plasma in the decolorizing liquid again, and at the same time adsorbs the small molecular pigments therein to further decolorize the decolorizing liquid, so that the transmittance of the bamboo biomass sugar liquid reaches more than 90%.

[0055] Furthermore, the ion exchange column includes at least one cation exchange column and at least one anion exchange column to ensure sufficient removal of different types of ions.

[0056] Furthermore, the cation exchange column and the anion exchange column are arranged at intervals.

[0057] (6) Reconcentration: Concentrating the bamboo biomass sugar solution to a concentration of 55%-65% to obtain concentrated syrup.

[0058] Furthermore, the re-concentration step includes two steps: ① pumping the bamboo biomass sugar solution into a membrane filter device for concentration to obtain a bamboo biomass sugar concentrate with a concentration of 20%-22%, and sending the concentrate into a bamboo biomass sugar concentrate tank.

[0059] ② The bamboo biomass sugar concentrate is pumped into a plate evaporator to be concentrated to 55%-65% to obtain the concentrated syrup.

[0060] Furthermore, the permeate from the concentration process of the membrane device in step ① and the evaporated condensed water from the plate evaporator in step ② are both sent to the pretreatment medium tank for use in the bamboo raw material pretreatment in step (2).

[0061] Wherein, the filter membrane device preferably adopts a ceramic nanofiltration membrane; the plate evaporator is heated by steam.

[0062] (7) Chromatographic separation: The concentrated syrup is separated by a continuous chromatographic separation device to obtain oligoxylose liquid and xylose liquid with a concentration of 30%-50%.

[0063] Chromatographic separation is based on the fact that different substances have different distribution coefficients in a system composed of a stationary phase and a mobile phase, and exhibit different retention times during the elution process using the mobile phase, thereby achieving separation.

[0064] Traditional chromatographic separation technology uses a fixed chromatographic tower. A certain amount of material is first introduced, and then an eluent is used to continuously elute it. Different product components can be received at the same outlet at different time periods. This process is time-consuming and labor-intensive.

[0065] In the present application, the concentrated syrup is separated by using an SSMB sequential simulated moving bed, thereby achieving efficient separation of multiple components in biomass sugar preparation, with high purity of each component and low preparation cost.

[0066] Furthermore, the concentrated syrup obtained in step (6) needs to be cooled to 60-70°C and then sent to the SSMB sequential simulated moving bed for chromatographic separation.

[0067] The preparation method of bamboo biomass sugar provided in this application overcomes the defect in the prior art that bamboo hemicellulose is not fully utilized. Bamboo biomass sugar liquid is efficiently prepared using bamboo as raw material. The bamboo biomass sugar liquid contains 5%-50% of oligoxylose and 30%-70% of xylose, and the purity of both components is above 90%.

[0068] Among them, xylose is the main product after the hydrolysis of bamboo hemicellulose, and oligoxylose is the product of the polymerization of 2-7 xylose molecules. Both are white to colorless sugars that are easily soluble in water.

[0069] In the bamboo biomass sugar preparation method, membrane concentration is used in the liquid concentration process, which can greatly reduce the steam consumption, better remove salt ions in the liquid, and save the resin consumption.

[0070] In some embodiments of the present application, the method for preparing bamboo biomass sugar further includes the steps of concentrating the xylooligosaccharide liquid and the xylose liquid respectively, and drying the concentrated xylooligosaccharide liquid and the xylose liquid respectively through a high-pressure pump into a spray dryer to obtain powdered xylooligosaccharides and powdered xylose.

[0071] Furthermore, a two-effect plate evaporator is used to evaporate and concentrate the xylooligosaccharide liquid and xylose liquid to obtain a xylooligosaccharide liquid and xylose liquid with a concentration of more than 85%. The xylooligosaccharide liquid and xylose liquid with a concentration of more than 85% are respectively pumped into a spray dryer through a high-pressure pump for drying to obtain powdered xylooligosaccharides and powdered xylose.

[0072] Wherein, the plate evaporator is heated by steam.

[0073] Furthermore, the hot air inlet temperature of the spray dryer does not exceed 140°C, and the outlet temperature does not exceed 110°C.

[0074] Furthermore, the hot air fed into the spray dryer is filtered to remove dust and sterilize.

[0075] In this embodiment, the powdered xylo-oligosaccharides and powdered xylose are obtained by a spray dryer drying method, which avoids the problems of slow crystallization speed and difficult mother liquor treatment in the crystallization method, and directly produces powdered bamboo biomass sugar products, which are convenient for storage and transportation.

[0076] In some embodiments of the present application, the method for preparing bamboo biomass sugar further includes the step of injecting clean water into the hydrolysis reaction tank to continue washing the residual acid in the reaction residue after the sugar recovery liquid is pumped out to the sugar recovery liquid tank, and the washing water is pumped out to the washing liquid tank for standby use. The washing water can be sent to the hydrolysis medium tank for use in the sugar recovery process.

[0077] The hydrolysis medium tank is used to store the hydrolysis medium. Clean water and sulfuric acid are added to the hydrolysis medium tank as needed to make the concentration of sulfuric acid in the hydrolysis medium 0.5%-3%.

[0078] In this step, the washing water is recovered / collected independently from the aforementioned pretreatment liquid, hydrolyzed liquid, sugar recovery liquid, permeate from each concentration stage, and condensed water. Liquids from each stage will not cross, thus ensuring the quality stability of the products from each process.

[0079] Furthermore, the pH of the reaction residue after washing is controlled to be 5-7, so as to facilitate subsequent storage and use.

[0080] Furthermore, after the washing of the reaction residue is completed, the walls of the hydrolysis reaction tank are opened to spray dilution water, and the reaction residue is pumped out to the residual material bin through a dedicated pump, and the filtrate is recycled as spray dilution water.

[0081] The preparation method of bamboo biomass sugar described in this application has a total water reuse rate of 70%.

[0082] The reaction residue in the residual material bin is dehydrated and then spirally transported to the pulping workshop for use as special pulp raw material. The flaky residue can be used as raw material for the production of dissolving pulp and fluff pulp, and the shavings or powdery residue can be dried and mixed with coal as fuel.

[0083] Existing techniques for extracting xylose or oligosaccharides from jade cores typically use biomass boilers to burn the residue, generating no added value. However, the bamboo material extracted from biomass sugars in this application can be used to produce dissolving pulp and fluff pulp, generating more added value and significantly increasing the overall value of bamboo resources. This also breaks down barriers to low-value bamboo utilization.

[0084] The present invention will be described in further detail below in conjunction with the examples. It is particularly noted that the following examples are only intended to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only some embodiments of the present application and not all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative work are intended to fall within the scope of protection of the present invention.

[0085] Example 1: This embodiment provides a method for preparing bamboo biomass sugar, comprising the following steps: S11. Material preparation: The raw bamboo is processed into bamboo strips 3-5 cm long and 1-2 cm wide, which are then washed in two series-connected washing machines to obtain bamboo raw materials.

[0086] S12. Pretreatment: adding a pretreatment medium to the bamboo raw material for pretreatment.

[0087] The pretreatment medium contains 0.08% sulfuric acid, and the pretreatment is performed for 1 hour.

[0088] S13. Sugar extraction: A hydrolysis medium was added to the pretreated bamboo raw material at a solid-liquid volume ratio of 1:2 to hydrolyze the hemicellulose in the bamboo raw material. After 3 hours of reaction, the hydrolyzate was cooled to 70°C by heat exchange and then discharged into the hydrolysis tank.

[0089] The hydrolysis medium is 2% sulfuric acid, and the hydrolysis temperature is 110°C.

[0090] The hydrolyzed liquid vapor produced by the hydrolysis reaction is fed to a jet condenser for condensation, and the resulting condensate is circulated to wash the reaction residue to obtain a sugar recovery liquid. In this step, the volume of the circulating washing water is controlled to be 8 times the volume of the solids.

[0091] The hydrolyzate and the sugar recovery solution are mixed in a mass ratio of 1:1 to obtain a mixed solution.

[0092] S14. Neutralization: Calcium carbonate slurry was slowly added to the mixed solution under stirring conditions to carry out neutralization reaction at a reaction temperature of 80° C. for 1 hour to obtain a neutralized solution.

[0093] The neutralized liquid is subjected to solid-liquid separation using a closed plate-and-frame filter, and the calcium sulfate crystal salt is filtered out to obtain a clear liquid.

[0094] S15. Concentration and purification: a. Pump the clear liquid into a membrane filter device for desalination and concentration to obtain a concentrated liquid.

[0095] The membrane filter device adopts a ceramic nanofiltration membrane with a molecular weight cut-off value of 200Da.

[0096] b. Add activated carbon to the concentrated solution under stirring for decolorization, and heat to 80°C for 1 hour.

[0097] The decolorized concentrated liquid is subjected to solid-liquid separation using a closed plate-and-frame filter, and the activated carbon mud powder is filtered out to obtain a decolorized liquid; and the transmittance of the decolorized liquid after solid-liquid separation is controlled to be above 80%.

[0098] c. The decolorized liquid is pumped into an ion exchange column for ion exchange purification to obtain a bamboo biomass sugar solution, wherein the transmittance of the bamboo biomass sugar solution reaches more than 90%.

[0099] The ion exchange columns are provided in three groups, and the arrangement order is cation exchange column-anion exchange column-cation exchange column.

[0100] S16. Reconcentration: Concentrating the bamboo biomass sugar solution to a concentration of 60% to obtain a concentrated syrup.

[0101] Specifically, the bamboo biomass sugar solution is first pumped into a membrane filter device for concentration to obtain a bamboo biomass sugar concentrate with a concentration of 20%-22%; then the bamboo biomass sugar concentrate is pumped into a plate evaporator for concentration to 60% to obtain the concentrated syrup.

[0102] S17. Chromatographic separation: The concentrated syrup is cooled to 60° C. and then fed into an SSMB sequential simulated moving bed for chromatographic separation to obtain a xylo-oligosaccharide solution with a concentration of 50% and a xylose solution with a concentration of 46%.

[0103] S18. The xylooligosaccharide liquid and the xylose liquid are respectively concentrated to above 85% by using a double-effect plate evaporator, and the concentrated xylooligosaccharide liquid and the xylose liquid are respectively fed into a spray dryer through a high-pressure pump for drying to obtain powdered xylooligosaccharides and powdered xylose.

[0104] The purity of the powdered xylo-oligosaccharide is 93%; the purity of the powdered xylose is 95%.

[0105] Example 2: This embodiment provides a method for preparing bamboo biomass sugar, comprising the following steps: S21. Material preparation: The raw bamboo is processed into bamboo strips 3-5 cm long and 1-2 cm wide, which are then washed in two series-connected washing machines to obtain bamboo raw materials.

[0106] S22. Pretreatment: adding a pretreatment medium to the bamboo raw material for pretreatment.

[0107] The pretreatment medium contains 0.12% sulfuric acid, and the pretreatment takes 2 hours.

[0108] S23. Sugar extraction: A hydrolysis medium was added to the pretreated bamboo raw material at a solid-liquid volume ratio of 1:4 to hydrolyze the hemicellulose in the bamboo raw material. After 4 hours of reaction, the hydrolyzed liquid after the cooling reaction was first cooled to 80°C by heat exchange and then discharged into the hydrolysis liquid tank to discharge the hydrolyzed liquid after the reaction.

[0109] The hydrolysis medium is 1.5% sulfuric acid, and the hydrolysis temperature is 120°C.

[0110] Water is added to circulate and wash the reaction residue to obtain a sugar recovery solution. In this step, the volume of the circulating washing water is controlled to be 4 times the volume of the solid matter.

[0111] The hydrolyzate and the sugar recovery solution were mixed at a mass ratio of 1:1.5 to obtain a mixed solution.

[0112] S24. Neutralization: Calcium carbonate slurry was slowly added to the mixed solution under stirring conditions to carry out neutralization reaction at a reaction temperature of 75° C. for a reaction time of 0.5 hour to obtain a neutralized solution.

[0113] The neutralized liquid is subjected to solid-liquid separation, and the calcium sulfate crystal salt is filtered out to obtain a clear liquid.

[0114] S25. Concentration and purification: a. Pump the clear liquid into a membrane filter device for desalination and concentration to obtain a concentrate.

[0115] The membrane filter device adopts a ceramic nanofiltration membrane with a molecular weight cut-off value of 150Da.

[0116] b. Add activated carbon to the concentrated solution under stirring for decolorization, and heat to 70°C for 0.5 hours.

[0117] The decolorized concentrated liquid is subjected to solid-liquid separation, and the activated carbon mud powder is filtered out to obtain a decolorized liquid; and the transmittance of the decolorized liquid after the solid-liquid separation is controlled to be above 80%.

[0118] c. The decolorized liquid is pumped into an ion exchange column for ion exchange purification to obtain a bamboo biomass sugar solution, wherein the transmittance of the bamboo biomass sugar solution reaches more than 90%.

[0119] The ion exchange columns are provided in four groups, and the arrangement order is cation exchange column-anion exchange column-cation exchange column-anion exchange column.

[0120] S26. Reconcentration: Concentrating the bamboo biomass sugar solution to a concentration of 65% to obtain a concentrated syrup.

[0121] Specifically, the bamboo biomass sugar solution is first pumped into a membrane filter device for concentration to obtain a bamboo biomass sugar concentrate with a concentration of 20%-22%; then the bamboo biomass sugar concentrate is pumped into a plate evaporator for concentration to 65% to obtain the concentrated syrup.

[0122] S27. Chromatographic separation: The concentrated syrup is cooled to 65°C and then fed into an SSMB sequential simulated moving bed for chromatographic separation. The concentrated syrup is separated using a continuous chromatographic separation device to obtain a xylo-oligosaccharide solution with a concentration of 45% and a xylose solution with a concentration of 39%.

[0123] The xylooligosaccharide liquid has a purity of 95%; the xylose liquid has a purity of 92%. The above description is only an embodiment of the present invention and does not limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the present invention specification, or directly or indirectly applied to other related technical fields, is also included in the scope of patent protection of the present invention.

Claims

1. A method for preparing bamboo biomass sugar, characterized in that: The steps include: (1) Material preparation: bamboo material is sliced ​​and / or made into bamboo chips and bamboo powder, and then washed with water to obtain bamboo raw material; (2) Pretreatment: adding a pretreatment medium to the bamboo raw material for pretreatment; The pretreatment medium contains 0.05%-0.12% sulfuric acid, and the pretreatment is performed for 0.5-2 hours; (3) Sugar extraction: 3a. A hydrolysis medium is added to the pretreated bamboo raw material to hydrolyze the hemicellulose in the bamboo raw material, and the hydrolyzate is discharged after the reaction and cooled; The hydrolysis medium is 0.5%-3% sulfuric acid, the hydrolysis temperature is 100-120°C, and the hydrolysis time is 1-4 hours; 3b adding water to cycle the washing reaction residue to obtain a sugar recovery liquid; 3c. mixing the hydrolyzate and the sugar recovery solution in a ratio of 1:1-1:2 to obtain a mixed solution; (4) Neutralization: 4a. Slowly adding calcium carbonate slurry to the mixture under stirring to carry out neutralization reaction, the reaction temperature is 75-85 ℃, the reaction time is 0.5-1 hour, to obtain a neutralized solution; 4b the neutralized solution was subjected to solid-liquid separation, filtering out the calcium sulfate crystals to obtain a clear solution; (5) Concentration and purification: 5a. The supernatant is pumped into a membrane device for desalination and concentration to obtain a concentrate; 5b. Adding activated carbon to the concentrate under stirring conditions for decolorization, and heating to 70-80 ℃, and keeping warm for 0.5-1 hours; 5c after decolorization of the concentrated liquid solid-liquid separation, filtered out the activated carbon sludge to obtain a decolorized liquid; 5d. The decolorized liquid was pumped into an ion exchange column for ion exchange purification to obtain bamboo biomass sugar solution; (6) re-concentrating: concentrating the bamboo biomass sugar solution to a concentration of 55%-65% to obtain a concentrated syrup; (7) Chromatographic separation: The concentrated syrup is separated by a continuous chromatographic separation device to obtain oligoxylose liquid and xylose liquid with a concentration of 30%-50%.

2. The preparation method according to claim 1, characterized in that: The preparation method also includes the steps of respectively concentrating the xylooligosaccharide liquid and the xylose liquid, and respectively drying the concentrated xylooligosaccharide liquid and the xylose liquid in a spray dryer through a high pressure pump to obtain powdered xylooligosaccharide and powdered xylose.

3. The preparation method according to claim 1, characterized in that: The hydrolyzate vapor produced by the hydrolysis reaction in step 3a is sent to a jet condenser for condensation, and the produced condensate is used for the circulating washing reaction residue in step 3b.

4. The preparation method according to claim 1, characterized in that: In step 4a, the pH of the neutralization solution is controlled to be 3.5-4; Alternatively, in step 5b, the amount of activated carbon is controlled to be 10%-30% of the total solids.

5. The preparation method according to claim 1, characterized in that: After step 5c, the decolorized liquid is pumped into a membrane filter device for desalination and concentration.

6. The preparation method according to claim 1 or 5, characterized in that: The filter membrane equipment adopts a ceramic nanofiltration membrane, and the molecular weight cutoff value of the filter membrane is 150-200Da.

7. The preparation method according to claim 1, characterized in that: In step 5d, the ion exchange column includes at least one cation exchange column and at least one anion exchange column.

8. The preparation method according to claim 1, characterized in that: Step (6) includes: 6a The bamboo biomass sugar solution was pumped into the membrane device to concentrate to obtain a concentration of 20% -22% bamboo biomass sugar concentrate; 6b. The bamboo biomass sugar concentrate is pumped into a plate evaporator and concentrated to 55%-65% to obtain the concentrated syrup.

9. The preparation method according to claim 1 or 8, characterized in that: The permeate in steps 5a and 6a and the evaporated condensate in step 6b are all sent to the pretreatment medium tank for use in the bamboo raw material pretreatment in step (2).

10. The preparation method according to claim 1, characterized in that: In step (7), the concentrated syrup is separated by using a SSMB sequential simulated moving bed.