Clean preparation method for co-producing mannose and arabinose through continuous method

Abstract

The invention relates to a clean preparation method for coproducing mannose and arabinose by a continuous method. The clean preparation method is characterized by comprising three units: a first unit, namely a preparation and purification unit of a crude sugar solution; the second unit is an arabinose refining extraction preparation and raffinate recycling unit; the third unit is a mannose refining extraction preparation and mannose chromatography raffinate recycling unit; the invention creatively provides a clean and efficient method for preparing mannose and arabinose by a continuous method, meanwhile, the production cost is effectively reduced, and the product yield is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of functional sugar production, and in particular relates to a clean preparation method for the co-production of mannose and arabinose by a continuous method. Background Art

[0002] Mannose, molecular formula is C6H 12 O6, molecular weight is 180.156, white crystals or crystalline powder, sweet and bitter. It is a kind of sugar that plays an important role in human metabolism, especially in the glycosylation of specific proteins. It generally exists in a free state in some plant peels, such as citrus peels. There is a small amount of free mannose in fruits such as peaches and apples. Mannose is also found in ivory palm seeds, yeast, red algae, serum globulin, ovomucoid and tuberculosis bacteria.

[0003] Mannose can be used as a carbohydrate nutrient in clinical practice. It is widely distributed in body fluids and tissues, especially in nerves, skin, testicles, retina, liver and intestines. It is directly used to synthesize glycoproteins and participate in immune regulation. Many diseases are caused by the lack of enzymes in the saccharification of mannose. It has many physiological effects in the human body: regulating the immune system; increasing wound healing; inhibiting tumor growth and metastasis, increasing cancer survival rate; anti-inflammatory effect; avoiding certain bacterial infections, etc.

[0004] Arabinose has a strong non-competitive inhibitory effect on sucrose absorption, and can inhibit the increase in serum glucose concentration caused by sucrose absorption. Therefore, it can be used as a sugar substitute sweetener for diabetics, obese people, and hypertensive patients. It can also be used as a precursor for the synthesis of certain drugs, such as certain nucleoside drugs for the treatment of liver disease. In the fine chemical industry, the reactive flavors of arabinose can produce a soft and rich aroma, giving the end product using the flavor a more natural and full aroma. L-arabinose can also be used as an anti-fading agent, in the production of L-arabinitol, etc. It is a rare sugar alcohol with a very wide application.

[0005] Traditional arabinose is mainly made from corn cobs. After purification, xylose is first crystallized and extracted, and then recovered from the xylose mother liquor. The mother liquor has a dark color and contains various impurities, and the purification cost is high. Mannose is mainly extracted from coconut shells, white fir trees, palm powder, etc. through acid hydrolysis, and has a low content and high extraction cost. Summary of the invention

[0006] In order to solve the defects of the prior art in the background technology, the present invention creatively uses hemicellulose powder as raw material, adopts continuous hydrolysis, continuous granular carbon tower decolorization, continuous ion exchange, flash-evaporation integrated concentration, simulated moving bed chromatography cycle separation and other processes, and then performs crystallization, centrifugation and drying to prepare mannose and arabinose respectively. The whole process realizes continuous, automatic and clean production.

[0007] A continuous clean preparation method for the co-production of mannose and arabinose comprises three units: the first unit is a preparation and purification unit for raw sugar solution; the second unit is a refined extraction preparation unit for arabinose and a raffinate recycling unit; the third unit is a refined extraction preparation unit for mannose and a mannose chromatography raffinate recycling unit; each unit specifically comprises the following steps: Unit 1: (1) Slurry preparation: hemicellulose powder and pure water are mixed and soaked in a ratio of 1:3-6 to allow the hemicellulose powder to fully absorb water and swell. After soaking, an acid catalyst is added to obtain a slurry preparation liquid; (2) Hydrolysis: the slurry preparation liquid is pumped into a steam liquefaction ejector, mixed with steam, and then sent into a hydrolysis kettle for heat preservation and pressure hydrolysis. The hydrolysis temperature is 100°C-120°C and the pressure holding time is 1h-3h; (3) Flash evaporation and cooling: after the hydrolysis is completed, the discharge valve of the hydrolysis kettle is opened and the material is sent into the flash evaporator of the flash evaporation system to recover heat through negative pressure flash evaporation while reducing the temperature of the feed liquid. (4) Continuous carbon tower decolorization: the material passing through the flash evaporator is pumped into the continuous granular carbon decolorization tower system, and the pigments and colloidal impurities in the liquid are removed by the adsorption of activated carbon; (5) Continuous ion exchange: the decolorized material is passed through an ion exchange column to remove anionic and cationic impurities; (6) Evaporation concentration: the material after ion exchange is sent to the flash evaporation system, and the material is heated by the hydrolysis waste heat recovered by the flash evaporator, and the liquid is concentrated by negative pressure evaporation; Unit 2: (7) Arabinose simulated moving bed chromatography separation: After purification and concentration, the feed liquid is separated by a simulated moving bed chromatography system. The extract is rich in arabinose and mannose and enters the next process; (8) Membrane concentration: The extract is concentrated by a high-pressure membrane to a refractive index of 20%-22%, and the permeate is reused in the slurry mixing process. The concentrated liquid enters the next process; (9) Concentration: After membrane concentration, the extract is concentrated by MVR low-temperature concentration and then enters the sugar boiling pot for further concentration, and the refractive index is controlled at 65%-75%; (10) Arabinose crystallization: After concentration, the feed liquid enters the crystallizer for cooling and crystallization; 11) Arabinose centrifugation: After the crystallization is completed, it is separated by a fully automatic centrifuge to obtain arabinose crystals and arabinose mother liquor rich in mannose. The purity of the arabinose crystals is ≥99%; the moisture content is ≤2.0%, and the refractive index of the resulting mother liquor is 50%-60%; (12) Drying and packaging: The arabinose crystals are sent into a vibrating fluidized bed for drying by a stirring wheel and then packaged into arabinose products according to market requirements. The purity of the finished product is ≥99%; the moisture content is ≤1.0%; Unit 3: (13) Ultrafiltration and impurity removal: The arabinose mother liquor rich in mannose described in step (11) is ultrafiltered to remove pigments and colloidal impurities. After impurity removal, the purity of mannose is ≥20%; (14) Secondary ion exchange: The ultrafiltration liquid is subjected to secondary ion exchange to remove anionic and cationic impurities generated during the production process and impurities not completely removed in the previous process; (15) Low-temperature evaporation: The material after the secondary ion exchange is subjected to low-temperature evaporation and concentration, and the vacuum degree is controlled at -0.07Mpa to -0.08Mpa, the temperature is 70-80°C, and the refractive index is controlled at 45%-55%; (16) Chromatographic separation of mannose: The evaporated material is subjected to chromatographic separation to extract mannose. The raffinate mainly contains xylose, arabinose, galactose and other miscellaneous sugars and is returned to step (6) for concentration and then subjected to chromatographic cycle extraction; (17) Mannose concentration: Extraction After the liquid is concentrated by MVR at low temperature, it enters the sugar boiling pot for further concentration, and the refractive index is controlled at 70%-85%; (18) Mannose crystallization: After concentration, the liquid enters the crystallizer for cooling and crystallization. By controlling the cooling gradient, the liquid is kept in a supersaturated state and crystals are continuously precipitated and grown; (19) Mannose centrifugation: After the crystallization is completed, it is separated by a fully automatic centrifuge to obtain mannose crystals and arabinose mother liquor rich in mannose. The purity of the mannose crystals is ≥99%, the moisture content is ≤2.0%, and the refractive index of the resulting mother liquor is 50%-60%; the mother liquor returns to step (15) for evaporation and concentration, and then undergoes chromatographic cyclic extraction; (20) Drying and packaging: The mannose crystals are sent to the vibrating fluidized bed for drying by a stirring wheel, and then packaged into mannose products according to market requirements. The purity of the finished product is ≥99%; the moisture content is ≤1.0%.

[0008] The above-mentioned continuous method for the clean preparation of mannose and arabinose co-production is preferably: Step (1) Slurry preparation: The acid catalyst may be one of sulfuric acid, hydrochloric acid, and acetic acid, or a mixture of several thereof; the hemicellulose powder may come from one of bamboo, wood, and straw, or a mixture of several thereof; and the hemicellulose powder has a mesh size of less than 30 meshes.

[0009] Step (3) Flash evaporation cooling: The equipment is a flash evaporation system, and the vacuum degree of the flash evaporation system is controlled to be -0.02Mpa to -0.06Mpa; the heat in the hydrolyzed material is fully recovered under negative pressure, and the vacuum degree of the evaporation system is controlled to be -0.07Mpa to -0.095Mpa; Step (4) continuous carbon tower decolorization as described above: the feed flow rate of the feed liquid is controlled to be 0.1BV-0.5BV; the feed temperature is 50℃-80℃; the light transmittance of the discharge material is ≥90%; the carbon tower adopts a pulsating bed adsorber, in which the carbon layer and the fluid are in counter-movement; the feed liquid enters the carbon tower from the bottom and is discharged from the top; the saturated carbon in the lower layer of the adsorber is taken out at regular intervals, the upper activated carbon is moved down layer by layer, and an equal amount of fresh carbon is added from the top of the adsorber.

[0010] Step (5) continuous ion exchange; the control conditions of the ion exchange column are: the light transmittance of the output is ≥95%; the conductivity is ≤20us / cm; the pH value is 3.0-6.5; column washing, online backwashing and cross regeneration are adopted; multiple columns are fed in parallel, and only one new column is cut in each time switching; Step (6) evaporation concentration: the material after ion exchange is sent to the flash evaporation system, and the vacuum degree is controlled to be -0.07Mpa to -0.095Mpa; the refractive index of the discharge material is controlled to be 45%-55%.

[0011] Step (7) Arabinose simulated moving bed chromatography separation: feed refractive index 45%-55%, turbidity ≤1NTU; Arabinose refractive index in extract ≥10%; Arabinose purity 75%-90%. The raffinate is rich in xylose, oligosaccharides and other miscellaneous sugars, which can be used for the extraction and utilization of xylose.

[0012] The ultrafiltration membrane selected in step (13) for removing impurities by ultrafiltration is a rolled ultrafiltration membrane with an operating temperature of 50°C-60°C and an operating pressure of 5.5-6.5Mpa.

[0013] In step (14) of ion exchange, the pH value of the discharge is controlled to be 3.5-6.5; the conductivity is ≤20us / cm; and the transmittance is ≥80%.

[0014] In step (16) of mannose chromatographic separation, the feed refractive index is 45%-55%, the turbidity is ≤1NTU; the mannose refractive index in the extract is ≥10%; the mannose purity is 55%-80%. The raffinate is returned to step (6) for concentration and then subjected to chromatographic cyclic extraction.

[0015] The cooling gradient in step (10) and step (18) is: when the temperature is above 50°C, the temperature is cooled at 0.5-1°C / h; when the temperature is below 50°C, the temperature is cooled at 1.0-2.0°C / h.

[0016] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The continuous carbon tower decolorization realizes continuous production. Continuous feeding and discharging make the material operation index more stable. It overcomes the product quality fluctuation caused by the difference in indexes between batches of traditional intermittent stirring tank decolorization.

[0017] Continuous carbon tower decolorization can be started with one button and run automatically, which greatly reduces labor costs.

[0018] The activated carbon used in continuous carbon tower decolorization is granular activated carbon, which replaces the powdered activated carbon used in traditional processes. Powdered activated carbon causes serious environmental pollution during the production process and is also very harmful to the workers' health. In addition, there are problems such as difficulty in recycling waste carbon and difficulty in regeneration. Currently, most manufacturers use powdered activated carbon as a disposable decolorization material, and the treatment of waste carbon has become a major burden for companies.

[0019] The invention creatively uses granular carbon, the pore shape of granular activated carbon is mainly cylindrical and V-shaped, with a larger specific surface area, which means a larger adsorption capacity, greatly reducing the amount of activated carbon used and reducing costs; The granular carbon used in the present invention is regenerable and recyclable. The used granular carbon can be regenerated by high-temperature incineration, and the regeneration effect is thorough, and it can be recycled, thereby reducing pollution to the environment and achieving the effect of energy saving and consumption reduction.

[0020] The present invention creatively uses a simulated moving bed continuous ion exchange system: the simulated moving bed continuous ion exchange system uses the carousel principle, and adsorption, washing, regeneration and elution are carried out simultaneously, with one-key start and fully automatic programmed operation. The feed, water, regeneration agent and feed temperature are automatically adjusted, and the pH value and conductivity are monitored online without human supervision.

[0021] The present invention creatively uses a simulated moving bed continuous ion exchange system: column washing, online backwashing and cross regeneration are adopted to ensure the exchange capacity of the resin. Multiple columns are fed in parallel, and only one new column is cut in each time switching, which reduces the influence of system fluctuations on the pH value of the output. Column regeneration makes full use of the regeneration agent and reduces the consumption of the regeneration agent; column washing reduces the amount of washing water and reduces the discharge of sewage; the consumption of acid, alkali and water is saved by nearly 70%.

[0022] The present invention uses a simulated moving bed chromatographic separation system to directly increase the purity of arabinose to 75-90%, and once crystallizes commercial arabinose. Compared with the traditional recrystallization process, the production process is greatly shortened, the equipment investment is reduced, and the production cost can be reduced.

[0023] The raffinate from chromatographic separation in each process section is returned to the previous process for cyclic extraction, which increases the product yield by 30%.

[0024] The co-production of mannose and arabinose as each other's main and by-products greatly reduces the overall production cost.

[0025] The integrated design of flash evaporation greatly reduces steam consumption and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the process of the present invention; DETAILED DESCRIPTION Example 1

[0027] (1) Slurry preparation: mix the 25-mesh hemicellulose powder treated with straw with deionized water in a ratio of 1:5, soak for 2 h, then add sulfuric acid to adjust the concentration of sulfuric acid to 2.5%.

[0028] (2) Hydrolysis: The slurry is pumped into a steam liquefaction ejector, mixed with steam, and then sent into a hydrolysis kettle for heat preservation and pressure hydrolysis. The hydrolysis temperature is 110°C-112°C and the hydrolysis time is 2.5 hours.

[0029] (3) Flash evaporation and cooling. After the hydrolysis is completed, the liquid is discharged to the flash evaporator for flash evaporation and cooling, and the vacuum degree is controlled at -0.03Mpa.

[0030] (4) Continuous carbon tower decolorization: The hydrolyzate in step (3) is decolorized by a granular activated carbon continuous carbon tower. The temperature is controlled at 72°C and the feed flow rate is 0.4 BV. A decolorized liquid is obtained with a light transmittance of 95.1%. The carbon tower removes the saturated carbon from the lower layer of the adsorber every 12 hours and adds an equal amount of fresh carbon from the upper part.

[0031] (5) Continuous ion exchange: the decolorized solution obtained in step (4) is passed through an ion exchange column to control the conductivity to 10 us / cm, the pH value to 6.0-6.5, and the transmittance to 99%.

[0032] (6) Evaporation and concentration: the purified liquid obtained in step (5) is concentrated to a mass percentage concentration of 54% using a double-effect evaporator.

[0033] (7) Arabinose simulated moving bed chromatography separation: the concentrated sugar solution obtained in step (6) is passed through a chromatography separation device to obtain an arabinose component. The chromatographic separation resin used is a calcium type cationic chromatographic separation resin. The feed refractive index is 52%, and the water-to-material ratio is 1:3. The obtained extract has an arabinose purity of 81% and a refractive index of 10.5%. The permeate is recycled to the slurry preparation process.

[0034] (8) Membrane concentration: the extract obtained in step (7) is concentrated to a refractive index of 20.5% by a high-pressure membrane.

[0035] (9) Concentrating: The concentrated sugar solution obtained in step (8) is concentrated to a refractive index of 74% by MVR cryogenic concentration.

[0036] (10) Arabinose crystallization: the sugar paste obtained in step (9) is cooled and crystallized, with the initial temperature being 70°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0037] (11) Arabinose is centrifuged, cooled, and centrifuged. The purity of the arabinose crystals is 99.4%, and the refractive index of the mother liquor is 58%.

[0038] (12) Dry packaging, arabinose crystal purity 99.35%, moisture 0.08%.

[0039] (13) Ultrafiltration to remove impurities: The mother liquor obtained in step (11) is ultrafiltered through a spiral ultrafiltration membrane to remove impurities at an operating temperature of 50° C. and an operating pressure of 5.5 MPa, and the purity of mannose in the filtrate is 28%.

[0040] (14) Secondary ion exchange: the material obtained in step (13) is subjected to ion exchange, and the output pH value is 6.2, the conductivity is 10 us / cm, and the transmittance is 99.5%.

[0041] (15) Low temperature evaporation: The material obtained in step (14) is evaporated and concentrated to a refractive index of 52% by low temperature evaporation, and the vacuum degree is controlled at -0.07 MPa and the temperature is 70°C.

[0042] (16) Chromatographic separation of mannose. The material obtained in step (15) is subjected to chromatographic separation. The refractive index of the feed is 52%, the refractive index of mannose in the extract is 12%, and the purity of mannose is 76%. The raffinate is returned to step (6) for concentration and then subjected to chromatographic separation and cyclic extraction.

[0043] (17) Mannose concentration: the concentrated sugar solution obtained in step (16) is concentrated to a refractive index of 73% by MVR cryogenic concentration.

[0044] (18) Mannose crystallization: the sugar paste obtained in step (17) is cooled and crystallized, with the initial temperature being 73°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0045] (19) The mannose is centrifuged, cooled, and centrifuged to separate the mannose crystals with a purity of 99.1% and a refractive index of 59%. The mother liquor is returned to step (15) for concentration and then chromatographic separation and cyclic extraction.

[0046] (20) Drying and packaging, the obtained mannose crystals have a purity of 99.1% and a moisture content of 0.7%.

[0047] In step (5) and step (14), the ion exchange column is set to a three-stage feed column, each stage is 5 parallel feed columns, and 10 functional columns are set, including 1 feed column, 1 defecation column, 3 regeneration columns, 2 backwash columns, and 3 elution columns, which can perform column washing, online backwashing and cross regeneration operations. The saturated feed column and the regenerated ion exchange column are switched one by one, so that the ion exchange column can be purified while in production. Example 2

[0048] (1) Slurry preparation: mix the wood treated 20 wood hemicellulose powder with deionized water in a ratio of 1:4, soak for 2.7 hours, then add hydrochloric acid to adjust the concentration of hydrochloric acid to 3%.

[0049] (2) Hydrolysis: The slurry is pumped into a steam liquefaction ejector, mixed with steam, and then sent into a hydrolysis kettle for heat preservation and pressure hydrolysis. The hydrolysis temperature is 102°C and the hydrolysis time is 3 hours.

[0050] (3) Flash evaporation and cooling. After the hydrolysis is completed, the liquid is discharged to the flash evaporator for flash evaporation and cooling, and the vacuum degree is controlled at -0.04Mpa.

[0051] (4) Continuous carbon tower decolorization: The hydrolyzate in step (3) is decolorized by a granular activated carbon continuous carbon tower. The temperature is controlled at 74°C and the feed flow rate is 0.4 BV. A decolorized liquid is obtained with a light transmittance of 95.4%. The carbon tower removes the saturated carbon from the lower layer of the adsorber every 16 hours and adds an equal amount of fresh carbon from the upper layer.

[0052] (5) Continuous ion exchange: the decolorized solution obtained in step (4) is passed through an ion exchange column to control the conductivity to 10 us / cm, the pH value to 6.3-6.5, and the transmittance to 98.7%.

[0053] (6) Evaporation and concentration: the purified liquid obtained in step (5) is concentrated to a mass percentage concentration of 51% using a double-effect evaporator.

[0054] (7) Arabinose simulated moving bed chromatography separation: the concentrated sugar solution obtained in step (6) is passed through a chromatography separation device to obtain an arabinose component. The chromatographic separation resin used is a calcium type cationic chromatographic separation resin. The feed refractive index is 52%, and the water-to-material ratio is 1:3. The obtained extract has an arabinose purity of 81.9% and a refractive index of 10.8%. The permeate is recycled to the slurry preparation process.

[0055] (8) Membrane concentration: the extract obtained in step (7) is concentrated to a refractive index of 21% by a high-pressure membrane.

[0056] (9) Concentrating: The concentrated sugar solution obtained in step (8) is concentrated to a refractive index of 75% by MVR cryogenic concentration.

[0057] (10) Arabinose crystallization: the sugar paste obtained in step (9) is cooled and crystallized, with the initial temperature being 70°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0058] (11) Arabinose is centrifuged, cooled, and centrifuged. The purity of the arabinose crystals is 99.4%, and the refractive index of the mother liquor is 58%.

[0059] (12) Dry packaging, arabinose crystal purity 99.35%, moisture 0.08%.

[0060] (13) Ultrafiltration to remove impurities: the mother liquor obtained in step (11) is ultrafiltered through a spiral ultrafiltration membrane to remove impurities at an operating temperature of 50° C. and an operating pressure of 5.5 MPa, and the purity of mannose in the filtrate is 27%.

[0061] (14) Secondary ion exchange: the material obtained in step (13) is subjected to ion exchange, and the output pH value is 6.3, the conductivity is 10 us / cm, and the transmittance is 99%.

[0062] (15) Low temperature evaporation: The material obtained in step (14) is evaporated and concentrated to a refractive index of 52% by low temperature evaporation, and the vacuum degree is controlled at -0.075 MPa and the temperature is 75°C.

[0063] (16) Chromatographic separation of mannose. The material obtained in step (15) is subjected to chromatographic separation. The refractive index of the feed is 51%, the refractive index of mannose in the extract is 12%, and the purity of mannose is 76%. The raffinate is returned to step (6) for concentration and then subjected to chromatographic separation and cyclic extraction.

[0064] (17) Mannose concentration: the concentrated sugar solution obtained in step (16) is concentrated to a refractive index of 73% by MVR cryogenic concentration.

[0065] (18) Mannose crystallization: the sugar paste obtained in step (17) is cooled and crystallized, with the initial temperature being 74°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0066] (19) The mannose is centrifuged, cooled, and centrifuged to separate the mannose crystals with a purity of 99.1% and a refractive index of 59%. The mother liquor is returned to step (15) for concentration and then chromatographic separation and cyclic extraction.

[0067] (20) After drying, the obtained mannose crystals have a purity of 99.1% and a moisture content of 0.7%.

[0068] In step (5) and step (14), the ion exchange column is set to a three-stage feed column, each stage is 5 parallel feed columns, and 10 functional columns are set, including 1 feed column, 1 defecation column, 4 regeneration columns, 4 backwash columns, and 4 elution columns, which can perform column washing, online backwashing and cross regeneration operations. The saturated feed column and the regenerated ion exchange column are switched one by one, so that the ion exchange column can be purified while in production. Example 3

[0069] (1) Slurry preparation: 20-mesh hemicellulose powder treated with bamboo was mixed with deionized water at a ratio of 1:5, and acetic acid was added after soaking for 2 h to adjust the acetic acid concentration to 3.5%.

[0070] (2) Hydrolysis: The slurry is pumped into a steam liquefaction ejector, mixed with steam, and then sent into a hydrolysis kettle for heat preservation and pressure hydrolysis. The hydrolysis temperature is 101°C and the hydrolysis time is 2.5 hours.

[0071] (3) Flash evaporation and cooling. After the hydrolysis is completed, the liquid is discharged to the flash evaporator for flash evaporation and cooling, and the vacuum degree is controlled at -0.03Mpa.

[0072] (4) Continuous carbon tower decolorization: The hydrolyzate in step (3) is decolorized by a granular activated carbon continuous carbon tower. The temperature is controlled at 73°C and the feed flow rate is 0.4 BV. A decolorized liquid is obtained with a light transmittance of 96%. The carbon tower removes the saturated carbon from the lower layer of the adsorber every 24 hours and adds an equal amount of fresh carbon from the upper layer.

[0073] (5) Continuous ion exchange: the decolorized solution obtained in step (4) is passed through an ion exchange column to control the conductivity to 10 us / cm, the pH value to 6.0-6.2, and the transmittance to 98.3%.

[0074] (6) Evaporation and concentration: the purified liquid obtained in step (5) is concentrated to a mass percentage concentration of 54% using a double-effect evaporator.

[0075] (7) Arabinose simulated moving bed chromatography separation: the concentrated sugar solution obtained in step (6) is passed through a chromatography separation device to obtain an arabinose component. The chromatographic separation resin used is a calcium type cationic chromatographic separation resin. The feed refractive index is 52%, and the water-to-material ratio is 1:3. The obtained extract has an arabinose purity of 81.8% and a refractive index of 11%, and the permeate is recycled to the slurry mixing process.

[0076] (8) Membrane concentration: the extract obtained in step (7) is concentrated to a refractive index of 20% by a high-pressure membrane.

[0077] (9) Concentrating: The concentrated sugar solution obtained in step (8) is concentrated to a refractive index of 75% by MVR cryogenic concentration.

[0078] (10) Arabinose crystallization: the sugar paste obtained in step (9) is cooled and crystallized, with the initial temperature being 71°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0079] (11) Arabinose is centrifuged, cooled, and centrifuged. The purity of the arabinose crystals is 99.4%, and the refractive index of the mother liquor is 58%.

[0080] (12) Dry packaging, arabinose crystal purity 99.4%, moisture 0.09%.

[0081] (13) Ultrafiltration to remove impurities: The mother liquor obtained in step (11) is ultrafiltered through a spiral ultrafiltration membrane to remove impurities at an operating temperature of 50° C. and an operating pressure of 5.5 MPa, and the purity of mannose in the filtrate is 28%.

[0082] (14) Secondary ion exchange: the material obtained in step (13) is subjected to ion exchange, and the output pH value is 6.5, the conductivity is 10 us / cm, and the transmittance is 98.5%.

[0083] (15) Low temperature evaporation: The material obtained in step (14) is evaporated and concentrated to a refractive index of 52% by low temperature evaporation, and the vacuum degree is controlled at -0.08 MPa and the temperature is 80°C.

[0084] (16) Chromatographic separation of mannose. The material obtained in step (15) is subjected to chromatographic separation. The refractive index of the feed is 52%, the refractive index of mannose in the extract is 13%, and the purity of mannose is 77%. The raffinate is returned to step (6) for concentration and then subjected to chromatographic separation and cyclic extraction.

[0085] (17) Mannose concentration: the concentrated sugar solution obtained in step (16) is concentrated to a refractive index of 73% by MVR cryogenic concentration.

[0086] (18) Mannose crystallization: the sugar paste obtained in step (17) is cooled and crystallized, with the initial temperature being 74°C and the cooling gradient being 1°C / h. After the temperature is below 50°C, the cooling gradient is 2°C / h.

[0087] (19) The mannose is centrifuged, cooled, and centrifuged. The purity of the mannose crystals is 99.1%, and the refractive index of the mother liquor is 589%. The mother liquor is returned to step (15) for concentration and then chromatographic separation and cyclic extraction.

[0088] (20) Drying and packaging, the obtained mannose crystals have a purity of 99.4% and a moisture content of 0.5%.

[0089] In step (5) and step (14), the ion exchange column is set to a three-stage feed column, each stage is 6 parallel feed columns, and 10 functional columns are set, including 1 feed column, 1 defecation column, 5 regeneration columns, 3 backwash columns, and 3 elution columns, which can perform column washing, online backwashing and cross regeneration operations. The saturated feed column and the regenerated ion exchange column are switched one by one, so that the ion exchange column can be purified while in production.

[0090] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. A clean preparation method for the co-production of mannose and arabinose by a continuous process, characterized by: It includes three units: the first unit is the preparation and purification unit of crude sugar solution; the second unit is the refined extraction preparation of arabinose and the recycling unit of the raffinate; the third unit is the refined extraction preparation of mannose and the recycling unit of the mannose chromatography raffinate; each unit specifically includes the following steps: Unit 1: (1) Slurry preparation: hemicellulose powder and pure water are mixed and soaked in a ratio of 1:3-6 to allow the hemicellulose powder to fully absorb water and swell. After soaking, an acid catalyst is added to obtain a slurry preparation liquid; (2) Hydrolysis: the slurry preparation liquid is pumped into a steam liquefaction ejector, mixed with steam, and then sent into a hydrolysis kettle for heat preservation and pressure hydrolysis. The hydrolysis temperature is 100°C-120°C and the pressure holding time is 1h-3h; (3) Flash evaporation and cooling: after the hydrolysis is completed, the discharge valve of the hydrolysis kettle is opened and the material is sent into the flash evaporator of the flash evaporation system to recover heat through negative pressure flash evaporation while reducing the temperature of the feed liquid. (4) Continuous carbon tower decolorization: the material passing through the flash evaporator is pumped into the continuous granular carbon decolorization tower system, and the pigments and colloidal impurities in the liquid are removed by the adsorption of activated carbon; (5) Continuous ion exchange: the decolorized material is passed through an ion exchange column to remove anionic and cationic impurities; (6) Evaporation concentration: the material after ion exchange is sent to the flash evaporation system, and the material is heated by the hydrolysis waste heat recovered by the flash evaporator, and the liquid is concentrated by negative pressure evaporation; Unit 2: (7) Arabinose simulated moving bed chromatography separation: After purification and concentration, the feed liquid is separated by a simulated moving bed chromatography system. The extract is rich in arabinose and mannose and enters the next process; (8) Membrane concentration: The extract is concentrated by a high-pressure membrane to a refractive index of 20%-22%, and the permeate is reused in the slurry mixing process. The concentrated liquid enters the next process; (9) Concentration: After membrane concentration, the extract is concentrated by MVR low-temperature concentration and then enters the sugar boiling pot for further concentration, and the refractive index is controlled at 65%-75%; (10) Arabinose crystallization: After concentration, the feed liquid enters the crystallizer for cooling and crystallization; 11) Arabinose centrifugation: After the crystallization is completed, it is separated by a fully automatic centrifuge to obtain arabinose crystals and arabinose mother liquor rich in mannose. The purity of the arabinose crystals is ≥99%; the moisture content is ≤2.0%, and the refractive index of the resulting mother liquor is 50%-60%; (12) Drying and packaging: The arabinose crystals are sent into a vibrating fluidized bed for drying by a stirring wheel and then packaged into arabinose products according to market requirements. The purity of the finished product is ≥99%; the moisture content is ≤1.0%; Unit 3: (13) Ultrafiltration and impurity removal: The arabinose mother liquor rich in mannose described in step (11) is ultrafiltered to remove pigments and colloidal impurities. After impurity removal, the purity of mannose is ≥20%; (14) Secondary ion exchange: The ultrafiltration liquid is subjected to secondary ion exchange to remove anionic and cationic impurities generated during the production process and impurities not completely removed in the previous process; (15) Low-temperature evaporation: The material after the secondary ion exchange is subjected to low-temperature evaporation and concentration, and the vacuum degree is controlled at -0.07Mpa to -0.08Mpa, the temperature is 70-80°C, and the refractive index is controlled at 45%-55%; (16) Chromatographic separation of mannose: The evaporated material is subjected to chromatographic separation to extract mannose. The raffinate mainly contains xylose, arabinose, galactose and other miscellaneous sugars and is returned to step (6) for concentration and then subjected to chromatographic cyclic extraction; (17) Mannose concentration: The extract is After MVR low-temperature concentration, it enters the sugar boiling pot for further concentration, and the refractive index is controlled at 70%-85%; (18) Mannose crystallization: After concentration, the feed liquid enters the crystallizer for cooling and crystallization. By controlling the cooling gradient, the feed liquid is kept in an oversaturated state and crystals are continuously precipitated and grown; (19) Mannose centrifugation: After the crystallization is completed, it is separated by a fully automatic centrifuge to obtain mannose crystals and arabinose mother liquor rich in mannose. The purity of the mannose crystals is ≥99%, the moisture content is ≤2.0%, and the refractive index of the resulting mother liquor is 50%-60%; the mother liquor returns to step (15) and is evaporated and concentrated, and then subjected to chromatographic cyclic extraction; (20) Drying and packaging: The mannose crystals are sent into a vibrating fluidized bed for drying through a stirring wheel, and then packaged into mannose products according to market requirements. The purity of the finished product is ≥99%; the moisture content is ≤1.0%XX.

2. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: Step (1) Slurry preparation: The acid catalyst may be one of sulfuric acid, hydrochloric acid, and acetic acid, or a mixture of several thereof; the hemicellulose powder may come from one of bamboo, wood, and straw, or a mixture of several thereof; and the hemicellulose powder has a mesh size of less than 30 meshes.

3. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: Step (3) Flash evaporation cooling: The equipment is a flash evaporation system, and the flash evaporation system controls the vacuum degree to be -0.02Mpa to -0.06Mpa; under negative pressure, the heat in the hydrolyzed material is fully recovered, and the evaporation system controls the vacuum degree to be -0.07Mpa to -0.095Mpa.

4. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: Step (4) continuous carbon tower decolorization as described above: the feed flow rate of the feed liquid is controlled to be 0.1BV-0.5BV; the feed temperature is 50℃-80℃; the light transmittance of the discharge material is ≥90%; the carbon tower adopts a pulsating bed adsorber, in which the carbon layer and the fluid are in counter-movement; the feed liquid enters the carbon tower from the bottom and is discharged from the top; the saturated carbon in the lower layer of the adsorber is taken out at regular intervals, the upper activated carbon is moved down layer by layer, and an equal amount of fresh carbon is added from the top of the adsorber.

5. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: Step (5) continuous ion exchange; the control conditions of the ion exchange column are: the output light transmittance ≥ 95%; the conductivity ≤ 20us / cm; the pH value 3.0-6.

5.

6. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: Step (6) evaporation concentration: the material after ion exchange is sent to the flash evaporation system, and the vacuum degree is controlled to be -0.07Mpa to -0.095Mpa; the refractive index of the discharge material is controlled to be 45%-55%.

7. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: In step (7), the feed refractive index of arabinose in simulated moving bed chromatography is 45%-55%, and the turbidity is ≤1NTU; the refractive index of arabinose in the extract is ≥10%; and the purity of arabinose is 75%-90%.

8. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: In step (14) of ion exchange, the pH value of the discharge is controlled to be 3.5-6.5; the conductivity is ≤20us / cm; and the transmittance is ≥80%.

9. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: In step (16) of mannose chromatographic separation, the feed refractive index is 45%-55%, and the turbidity is ≤1NTU; the mannose refractive index in the extract is ≥10%; the mannose purity is 55%-80%, and the raffinate is returned to step (6) for concentration and then subjected to chromatographic cyclic extraction.

10. The clean preparation method for the continuous co-production of mannose and arabinose according to claim 1, characterized in that: The cooling gradient in step (10) and step (18) is: when the temperature is above 50°C, the temperature is cooled at 0.5-1°C / h; when the temperature is below 50°C, the temperature is cooled at 1.0-2.0°C / h.

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