A method of preparing xylitol and mixing molasses from xylose mother liquidTechnical field
The present invention relates to xylose mother liquid reutilization technology fields, and in particular to one kind prepared from xylose mother liquid xylitol andThe method of mixing molasses.
Background technique
For xylitol as natural five-state controller, sugariness, heat and sucrose are suitable, are important functional food additivesOne of.The metabolism of xylitol does not need insulin, sweetener of the alternative sucrose as patients with diabetes mellitus.Meanwhile xyloseAlcohol, which is used in chewing gum, is used as sweetener, also has the function of maintaining oral cavity acid-base balance, pre- anti-caries.
The production method of xylitol is mainly chemical method at present, i.e., (contains 36 rich in poly-pentose using corncob, bagasse etc.~40% pentosan) raw material, through acid be hydrolyzed into the hydrolyzate containing xylose, then neutralized, decoloration, ion exchange, knotThe purification process of the complexity such as crystalline substance isolates and purifies out xylose from hydrolyzate, then adds hydrogen that xylose is made to generate xylose xylose chemistryAlcohol.
It is above-mentioned prepare xylitol during can generate a large amount of xylose mother liquid, the xylose of 1 ton of every Crystallization Separation to obtain the final productTo 0.8~1 ton of xylose mother liquid.The female sugared concentration of xylose is 50~60%, and wherein glucose contains 12~18% or so, and xylose contains 40~50% or so, arabinose contains 17~23%, and galactolipin contains 0~6%.Because miscellaneous sugar content is high, xylose purity is low, it is difficult to willXylose crystalline purification in mother liquor.Xylose mother liquid generally gives caramel colorant factory to undersell at present, produces caramel colorant, mother liquorIn the value of various monosaccharide especially xylose be not fully used, greatly reduce productivity effect.
In recent years, there is the research that some pairs of xylose mother liquids carry out the comprehensive utilization of high price value.
Patent CN105001272A describes a kind of processing method of xylose mother liquid, pre-processes without fermenting, simple process,Diluted xylose mother liquid is subjected to chromatographic isolation, obtains miscellaneous sugar liquid, Xylose and Arabic liquid glucose, Xylose successively carry out fromIt hands over, be concentrated and crystallize, obtain xylose.But this method needs mother liquor being diluted to 20~60%, subsequently into chromatographic isolation, obtainsThree kinds of components, concentration energy consumption are larger.
Patent CN 101643752B describes a kind of method using xylose mother liquid production xylitol and L-arabinose,By the xylose utilization yeast microbe conversion in xylose mother liquid at xylitol, and L- Arab is extracted with the method for chromatographic isolationSugar, but since yeast fermenting xylose is lower at the conversion ratio of xylitol, thus in xylose mother liquid xylose utilization rate compared withIt is low.
Patent CN101857523B, which is described, a kind of using xylose mother liquid while producing the side of xylitol and arabiteMethod, with yeast fermentation process by xylose mother liquid glucose and galactolipin remove, then first carry out hydrogenation, mixedSugar alcohol liquid is closed then to refine using chromatographic isolation xylitol fraction and arabite fraction；This method glucose and galaSugar is removed, and is not utilized.
To sum up, xylose mother liquid added value is improved as far as possible there is an urgent need to invent one kind to make full use of xylose mother liquid at presentMethod.
Summary of the invention
The method that the object of the present invention is to provide a kind of to prepare xylitol and mixing molasses from xylose mother liquid, it is existing to solveThere is the deficiency of technology.
The invention adopts the following technical scheme:
A method of it preparing xylitol and mixing molasses from xylose mother liquid, includes the following steps:
Step 1: pretreatment: taking xylose mother liquid, add calcium hydroxide solution in xylose mother liquid, adjust pH value to 8.5~9.0, soAfter be passed through carbon dioxide and carry out full charge, pH value is down to 6.6~7.0, and calcium hydroxide is during being changed into calcium carbonate by colloidElectrodeposition substance gets off, and then passes through diatomite aided filter, removes the colloidal substance of deposition；Then pass through cation exchange resinProcessing removal part calcium ion；
Step 2: chromatographic isolation: xylose mother liquid is after pretreatment, and into chromatographic fractionation system, xylose component passes through chromatographic columnAfter be able to separate with other miscellaneous sugar components, obtain containing the extracting solution and raffinate containing other miscellaneous sugar components that main component is xyloseLiquid；Amount of dry matter percent concentration is 15~25% in extracting solution, and the content of xylose is 80% or more；Raffinate amount of dry matter hundredDividing specific concentration is 8~20%, based on mannose, glucose；
Step 3: decolorization filtering: extracting solution uses powder activity carbon decoloring, is filtered to remove impurity；
Step 4: ion-exchange purifies: xylose extracting solution after decolorization filtering, into sun-concatenated ion exchange system of yin carry out fromHand over purification；
Step 5: evaporation: by the purified extracting solution of ion-exchange by being concentrated in vacuo to amount of dry matter percent concentration be 75~85%；Chromatography raffinate is concentrated in vacuo to amount of dry matter percent concentration 65~75%, obtains mixing molasses finished product, and saccharic composition is mainBy mannose, glucose group at wherein mannose accounts for 30 ~ 32%, and glucose accounts for 18 ~ 22%；
Step 6: crystallization: the extracting solution after vacuum concentration uses decrease temperature crystalline technique, controls crystallization yield 50%~55%；
Step 7: centrifugation, drying: the material after crystallization is centrifuged, later moisture content≤0.5% of drying control xylose；
Step 8: dissolution plus hydrogen: drinking water dissolves xylose, carries out hydrogenation reaction in hydrogenation reaction cauldron, is sunk after reactionIt removes except catalyst；
Step 9: purification: hydride being purified using sun-concatenated ion exchange system of yin, purified material passes throughVacuum evaporation to amount of dry matter percent concentration is 75~85%, carries out vacuum cane sugar boiling and crystal, xylitol crystal is precipitated,It is most centrifuged afterwards, dries to obtain xylitol crystal.
Further, step 1 xylose mother liquid amount of dry matter percent concentration is 50~60wt% of sugared concentration；Wherein, dryIn object, glucose contains 12~18 wt%, and xylose contains 40~50 wt%, and arabinose contains 17~23 wt%, mannose containing 10 ~22 wt %, galactolipin contain 0~6 wt%.
Further, step 1 cation exchange resin is D001 type polystyrene macroporous type strong-acid cation exchange treeRouge, 55 ~ 65 DEG C of feeding temperature, charging pH 5.0 ~ 7.0, advanced material, 0.1 ~ 0.5L/min of feed rate, 10 ~ 50min of time,Laggard purified water, 0.1 ~ 0.5L/min of flow, 10 ~ 50min of time, discharging pH control is 1.5 ~ 6.0.
Further, step 2 chromatographic fractionation system is SSMB sequential type simulated moving bed chromatography separation system, chromatography materialMaterial is the Applexion of Novasep®XA resin, the resin are different to the binding force of xylose and miscellaneous sugar, and charging is connectedPush chromatographic isolation unit to continuously, then by the elution of eluent, realizes separation, wherein 50 ~ 65 DEG C of feeding temperature, chargingPH 1.5 ~ 6.0, material liquid 100 ~ 150ml/min of inlet amount, 100 ~ 200ml/min of inlet of eluent water, operation 10Reach balance after ~ 20h, xylose, miscellaneous sugar are extracted respectively.
Further, step 3 Powdered Activated Carbon addition quality is added by 1.0~the 3.0 ‰ of liquid quality, and 50 ~ 65 DEG C30 ~ 60min of lower maintenance.
Further, step 4 positive resin is D001 type polystyrene macroporous type strong-acid cation-exchange resin, negative resinFor D301 type polystyrene macroporous type weak basic anion exchange resin, 50 ~ 65 DEG C of feeding temperature, pH 2.0 ~ 7.0 is fed, firstInto material, 0.1 ~ 0.5L/min of feed rate, 10 ~ 50min of time, then into purified water, 0.1 ~ 0.5L/min of flow, time 10The ion-exchange liquid conductivity of ~ 50min, discharging control below 100 μ s/cm.
Further, the purified extracting solution of step 5 ion-exchange is concentrated in vacuo vacuum degree -0.075 ~ -0.095MPa, discharging60 ~ 75 DEG C of temperature；Chromatography raffinate be concentrated in vacuo vacuum degree -0.075 ~ -0.095MPa, 60 ~ 75 DEG C of drop temperature.
Further, step 6 is cooled to 35 ~ 45 DEG C, 2 ~ 10h of crystallization time.
Further, step 8 drinking water dissolves xylose, and refractive power is controlled in 50~60%, pH5.00~7.00；Add qualityThe Raney nickel that percentage is 0.8~2.0% controls 130~140 DEG C of reaction temperature, steam pressure 0.4MPa or more, reaction kettlePressure control in 7.0~9.5MPa, the reaction time 60~120 minutes, 99% or more conversion ratio.
Further, step 9 positive resin is D001 type polystyrene macroporous type strong-acid cation-exchange resin, negative resinFor D301 type polystyrene macroporous type weak basic anion exchange resin, 45 ~ 55 DEG C of feeding temperature, first into material, feed rate0.1 ~ 0.5L/min, 10 ~ 50min of time, then into purified water, 0.1 ~ 0.5L/min of flow, 10 ~ 50min of time, control dischargingConductivity≤10 μ s/cm.
Beneficial effects of the present invention:
1, xylose mother liquid is difficult to directly utilize, and needs to first pass through pretreatment, and the present invention locates in advance by calcium hydroxide and carbon dioxideReason, simple and easy compared with the prior art, effect is obvious, eliminates impurity, reduces the viscosity of xylose mother liquid, improves filteringSpeed.
2, after xylose mother liquid removal of impurities of the present invention, SSMB sequential type simulated moving bed chromatography separation system is first passed through, is mentionedLiquid and raffinate are taken, hydrogenation reaction is carried out after extracting solution purification and prepares xylitol, compared with first plus after hydrogen carrying out chromatographic isolation again,Some other monosaccharide such as mannose, glucose, galactolipin, arabinose etc. will not enter hydrogenation reaction together, substantially canRetained；The content of glucose and mannose is higher in the mixing molasses obtained after raffinate concentration, may be used as microorganismThe purposes such as fermenting carbon source；The various monosaccharide components of xylose mother liquid are all utilized, and the added value of xylose mother liquid is improved.
Specific embodiment
The present invention is done below with reference to embodiment and is further explained.The following example is merely to illustrate the present invention, butIt is not used to limit practical range of the invention.
A method of it preparing xylitol and mixing molasses from xylose mother liquid, includes the following steps:
Step 1: pretreatment: xylose mother liquid is taken, xylose mother liquid amount of dry matter percent concentration is 50~60wt% of sugared concentration,In, in dry, glucose contains 12~18 wt%, and xylose contains 40~50 wt%, and arabinose contains 17~23 wt%, sweet dewSugar contains 10 ~ 22 wt %, and galactolipin contains 0~6 wt%；Calcium hydroxide solution is added in xylose mother liquid (to be configured to 50 DEG C of warm waterThe calcium hydroxide solution of 20 ~ 70wt%), pH value is adjusted to 8.5~9.0, is then passed to carbon dioxide and is carried out full charge, carbon dioxideFlow velocity is 5 ~ 25L/min, and pH value is down to 6.6~7.0, and calcium hydroxide sinks colloidal substance during being changed into calcium carbonateIt accumulates, then passes through diatomite aided filter, remove the colloidal substance of deposition；Then it is gone by cation exchange resin processingExcept part calcium ion, cation exchange resin is D001 type polystyrene macroporous type strong-acid cation-exchange resin, feeding temperature55 ~ 65 DEG C, charging pH5.0 ~ 7.0, advanced material, 0.1 ~ 0.5L/min of feed rate, 10 ~ 50min of time, laggard purified water,0.1 ~ 0.5L/min of flow, 10 ~ 50min of time, discharging pH control is 1.5 ~ 6.0.
Step 2: chromatographic isolation: xylose mother liquid is after pretreatment, and into chromatographic fractionation system, chromatographic fractionation system isSSMB sequential type simulated moving bed chromatography separation system, chromatographic material are the Applexion of Novasep®XA resin, the treeRouge is different to the binding force of xylose and miscellaneous sugar, and charging is continuously pushed to chromatographic isolation unit, then passes through eluentSeparation is realized in elution, wherein 50 ~ 65 DEG C of feeding temperature, pH 1.5 ~ 6.0, material liquid 100 ~ 150ml/min of inlet amount are fed,100 ~ 200ml/min of inlet of eluent water reaches balance after running 10 ~ 20h, and xylose, miscellaneous sugar are extracted respectivelyCome.Xylose component is able to separate with other miscellaneous sugar components after chromatographic column, obtain containing main component be xylose extracting solution andRaffinate containing other miscellaneous sugar components；As shown in table 1, amount of dry matter percent concentration is 15~25% in extracting solution, xyloseContent is 80% or more；Raffinate amount of dry matter percent concentration is 8~20%, based on mannose, glucose.
1 extracting solution of table and raffinate (mixing molasses) various contents of monosaccharides
| Xylose % | Glucose % | Galactolipin % | Arabinose % | Mannose % |
| Extracting solution | 80~83 | 3~4 | 0.5~1 | 2~4 | 4~5 |
| Raffinate | 5~8 | 18~22 | 8~12 | 15~18 | 30~32 |
Step 3: decolorization filtering: extracting solution uses powder activity carbon decoloring, and Powdered Activated Carbon adds quality by liquid quality1.0~3.0 ‰ add, and 30 ~ 60min is maintained at 50 ~ 65 DEG C, is filtered to remove impurity.
Step 4: ion-exchange purifies: xylose extracting solution after decolorization filtering, into sun-concatenated ion exchange system of yin intoThe purification of row ion-exchange, positive resin are D001 type polystyrene macroporous type strong-acid cation-exchange resin, and negative resin is D301 type benzene secondAlkene system macroporous type weak basic anion exchange resin, feeds pH 2.0 ~ 7.0, first into material, feeding flow by 50 ~ 65 DEG C of feeding temperature0.1 ~ 0.5L/min, 10 ~ 50min of time are measured, then into purified water, 0.1 ~ 0.5L/min of flow, 10 ~ 50min of time, dischargingIon-exchange liquid conductivity controls below 100 μ s/cm.
Step 5: evaporation: it is 75 that the purified extracting solution process of ion-exchange, which is concentrated in vacuo to amount of dry matter percent concentration,~85%, vacuum degree -0.075 ~ -0.095MPa, 60 ~ 75 DEG C of drop temperature；Chromatography raffinate is concentrated in vacuo to amount of dry matter hundredPoint specific concentration 65~75%, vacuum degree -0.075 ~ -0.095MPa, obtain mixing molasses finished product by 60 ~ 75 DEG C of drop temperature, and sugared groupDivide mainly by mannose, glucose group at wherein mannose accounts for 30 ~ 32%, and glucose accounts for 18 ~ 22%.
Step 6: crystallization: extracting solution after vacuum concentration uses decrease temperature crystalline technique, is cooled to 35 ~ 45 DEG C, the time 2 ~10h controls crystallization yield 50%~55%.
Step 7: centrifugation, drying: 4000 ~ 8000 rpm of material after crystallization is centrifuged 20 ~ 60min, 1 ~ 5h at 60 ~ 70 DEG C,Control moisture content≤0.5% of xylose.
Step 8: dissolution plus hydrogen: drinking water dissolves xylose, and refractive power is controlled in 50~60%, pH5.00~7.00；Hydrogenation is anti-It answers and carries out hydrogenation reaction in kettle, the Raney nickel that addition mass percent is 0.8~2.0% controls reaction temperature 130~140DEG C, steam pressure 0.4MPa or more, the pressure control of reaction kettle the reaction time 60~120 minutes, is converted in 7.0~9.5MPa99% or more rate carries out sedimentation removal catalyst after reaction.
Step 9: purification: hydride being purified using sun-concatenated ion exchange system of yin, positive resin D001Type polystyrene macroporous type strong-acid cation-exchange resin, negative resin are the exchange of D301 type polystyrene macroporous type weak base anionResin, 45 ~ 55 DEG C of feeding temperature, first into material, 0.1 ~ 0.5L/min of feed rate, 10 ~ 50min of time, then into purifyingWater, 0.1 ~ 0.5L/min of flow, 10 ~ 50min of time, control discharging conductivity≤10 μ s/cm；Purified material is in vacuumSpending vacuum evaporation to amount of dry matter percent concentration under -0.075 ~ -0.095MPa is 75~85%, vacuum degree 100 ~Under 130mbar carry out vacuum cane sugar boiling and crystal, xylitol crystal is precipitated, most afterwards through 4000 ~ 8000 rpm be centrifuged 10 ~ 30min, 80DEG C drying 20 ~ 60min, obtain xylitol crystal.
Embodiment 1
1, prepare xylose mother liquid 5L: amount of dry matter percent concentration (sugared concentration) about 50%, wherein glucose contains 12% in dryLeft and right, xylose contain 46% or so, and arabinose contains 18%, and mannose 18%, galactolipin contains 3%.
2, pre-process: xylose mother liquid adds calcium hydroxide solution, and (calcium hydroxide for being configured to 50wt% with 50 DEG C of warm water is moltenLiquid), adjusting pH value to 9.0 then passes to carbon dioxide and carries out full charge, carbon dioxide flow rate 15L/min, and pH value is down to 6.85,Calcium hydroxide deposits colloidal substance during being changed into calcium carbonate, then passes through diatomite aided filter, removesThe colloidal substance of deposition.Then it is handled by D001 type polystyrene macroporous type strong-acid cation-exchange resin, feeding temperature 58DEG C, feed pH6.0, advanced material, feed rate 0.2L/min, time 25min, laggard purified water, flow 0.2L/min, time25min, discharging pH control is 2.3.
Xylose mother liquid and pretreated xylose mother liquid each 1000 ml before taking pretreatment, it is true by middling speed qualitative filter paperEmpty pump filters (- 0.095MPa), manual time-keeping, calculates the rate of filtration, the results are shown in Table 2.
The pretreatment of table 2 front and back rate of filtration situation
| Rate of filtration ml/min |
| Before pretreatment | 35.0 |
| After pretreatment | 80.0 |
3, chromatographic isolation: xylose mother liquid is after pretreatment, into SSMB sequential type simulated moving bed chromatography separation system, chromatographyMaterial is the Applexion XA resin of Novasep, and the resin is different to the binding force of xylose and miscellaneous sugar, chargingContinuously pushed to chromatographic isolation unit, by the elution of eluent, realizes separation, wherein 55 DEG C of feeding temperature, pH:2.3,Material liquid inlet amount 140ml/min, the inlet 180ml/min of eluent water reach balance after running 16h, xylose, miscellaneousSugar is extracted respectively.Xylose component therein is able to separate with other miscellaneous sugar components after chromatographic column, obtains containing mainIngredient is the extracting solution of xylose and the raffinate containing other miscellaneous sugar components.Amount of dry matter percent concentration is 20% in extracting solution,The content of xylose is 80% or more；Raffinate amount of dry matter percent concentration is 12%, based on mannose, glucose.
4, decolorization filtering: extracting solution uses powder activity carbon decoloring, and Powdered Activated Carbon adds quality by liquid quality2.0 ‰ add, and maintain 60min at 50 DEG C, are filtered to remove impurity.
5, ion-exchange purifies: xylose extracting solution carries out ion-exchange after decolorization filtering, into sun-concatenated ion exchange system of yinPurification, wherein positive resin is D001 type polystyrene macroporous type strong-acid cation-exchange resin, and negative resin is D301 type styreneIt is macroporous type weak basic anion exchange resin, 50 DEG C of feeding temperature, feeds pH2.35, advanced material, feed rate 0.2L/min,Time 25min, laggard purified water, flow 0.2L/min, time 25min.The ion-exchange liquid conductivity that discharges control is in 100 us/cmBelow.
6, it evaporates: the purified extracting solution of ion-exchange is concentrated in vacuo to amount of dry matter percentage 82% or so, vacuum degree-0.095Mpa, 75 DEG C of drop temperature.Chromatography raffinate is concentrated to dryness amount of substance percentage 70% or so, vacuum degree -0.095Mpa,75 DEG C of drop temperature, mixing molasses finished product is obtained, mannose content is 30% in saccharic composition, glucose content 20%.
7, crystallize: the extracting solution after vacuum concentration uses decrease temperature crystalline technique, is cooled to 45 DEG C, time 6h by 75 DEG C, knotBrilliant yield 50%.
8, be centrifuged, be dry: the material after crystallization is centrifuged 40min, dry 4h at 65 DEG C, the water of xylose by 5000 rpmDivide content≤0.5%.
9, it dissolves, add hydrogen: dissolving xylose with drinking water, refractive power is controlled in 50%, pH:6.0；Added in hydrogenation reaction cauldronHydrogen reaction, the Raney nickel that addition mass percent is 1.5%, controls 140 DEG C of reaction temperature, steam pressure 0.4MPa or more,The pressure control of reaction kettle is in 9.0MPa, and the reaction time 100 minutes, 99% or more conversion ratio.Sedimentation removal is carried out after reactionCatalyst.
10, it refines: hydride being purified using sun-yin series connection ion exchange system, positive resin is D001 type polystyreneMacroporous type strong-acid cation-exchange resin, negative resin are D301 type polystyrene macroporous type weak basic anion exchange resin, chargingTemperature 50 C, advanced material, feed rate 0.25L/min, time 20min, laggard purified water, flow 0.25L/min, time20min.The ion-exchange liquid conductivity that discharges control is below 10 μ s/cm.Vacuum evaporation is extremely at vacuum degree -0.095MPa for materialAmount of dry matter percent concentration is 82%, carries out vacuum cane sugar boiling and crystal under vacuum degree 120mbar, xylitol crystal is precipitated, mostIt is centrifuged 15min by 5000 rpm, 80 DEG C of drying 60min obtain xylitol crystal.
Embodiment 2
1, prepare xylose mother liquid 5L: amount of dry matter percent concentration (sugared concentration) about 55%, wherein glucose contains 14% in dryLeft and right, xylose contain 48% or so, and arabinose contains 17%, and mannose 18%, galactolipin contains 3%.
2, pre-process: xylose mother liquid adds calcium hydroxide solution, and (calcium hydroxide for being configured to 50wt% with 50 DEG C of warm water is moltenLiquid), adjusting pH value to 9.0 then passes to carbon dioxide and carries out full charge, carbon dioxide flow rate 15L/min, and pH value is down to 6.95,Calcium hydroxide deposits colloidal substance during being changed into calcium carbonate, then passes through diatomite aided filter, removesThe colloidal substance of deposition.Then it is handled by D001 type polystyrene macroporous type strong-acid cation-exchange resin, feeding temperature 60DEG C, charging pH6.2, advanced material, feed rate 0.25L/min, time 20min, laggard purified water, flow 0.25L/min, whenBetween 20min, discharge pH:2.5.
3, chromatographic isolation: xylose mother liquid is after pretreatment, into SSMB sequential type simulated moving bed chromatography separation system,Chromatographic material is the Applexion XA resin of Novasep, and the resin is different to the binding force of xylose and miscellaneous sugar,Charging is continuously pushed to chromatographic isolation unit, by the elution of eluent, realizes separation, wherein and 55 DEG C of feeding temperature, pH:2.5, material liquid inlet amount 150ml/min, the inlet 200ml/min of eluent water reach balance after running 14h, woodSugar, miscellaneous sugar are extracted respectively.Xylose component therein is able to separate with other miscellaneous sugar components after chromatographic column, is containedMain component is the extracting solution of xylose and the raffinate containing other miscellaneous sugar components.Amount of dry matter percent concentration is in extracting solution21%, the content of xylose is 83% or more；Raffinate amount of dry matter percent concentration is 12%, based on mannose, glucose.
4, decolorization filtering: extracting solution uses powder activity carbon decoloring, and Powdered Activated Carbon addition quality adds by the 2.0 ‰ of liquid qualityAdd, maintains 60min at 50 DEG C, be filtered to remove impurity.
5, ion-exchange purifies: xylose extracting solution carries out ion-exchange after decolorization filtering, into sun-concatenated ion exchange system of yinPurification, wherein positive resin is D001 type polystyrene macroporous type strong-acid cation-exchange resin, and negative resin is D301 type styreneIt is macroporous type weak basic anion exchange resin, 50 DEG C of feeding temperature, feeds pH:3.0, advanced material, feed rate 0.25L/Min, time 20min, laggard purified water, flow 0.25L/min, time 20min.The ion-exchange liquid conductivity that discharges control is 100Us/cm or less.
6, it evaporates: the purified extracting solution of ion-exchange is concentrated in vacuo to amount of dry matter percentage 80% or so, vacuum degree-0.095Mpa, 75 DEG C of drop temperature.Chromatography raffinate is concentrated to dryness amount of substance percentage 70% or so, vacuum degree -0.095Mpa,75 DEG C of drop temperature, mixing molasses finished product is obtained, mannose content is 31% in saccharic composition, glucose content 18%.
7, crystallize: the extracting solution after vacuum concentration uses decrease temperature crystalline technique, is cooled to 45 DEG C, time 5h by 75 DEG C, controlCrystallization yield 52% processed.
8, be centrifuged, be dry: the material after crystallization is centrifuged 40min by 5000rpm, and dry 3.5h at 65 DEG C controls xyloseMoisture content≤0.5%.
9, it dissolves, add hydrogen: dissolving xylose with drinking water, refractive power is controlled in 50%, pH:6.0；Added in hydrogenation reaction cauldronHydrogen reaction, the Raney nickel that addition mass percent is 1.5%, controls 140 DEG C of reaction temperature, steam pressure 0.4MPa or more,The pressure control of reaction kettle is in 9.0MPa, and the reaction time 100 minutes, 99% or more conversion ratio.Sedimentation removal is carried out after reactionCatalyst.
10, it refines: hydride being purified using sun-yin series connection ion exchange system, positive resin is D001 type polystyreneMacroporous type strong-acid cation-exchange resin, negative resin are D301 type polystyrene macroporous type weak basic anion exchange resin, chargingTemperature 50 C, advanced material, feed rate 0.25L/min, time 20min, laggard purified water, flow 0.25L/min, time20min.The ion-exchange liquid conductivity that discharges control is below 10 μ s/cm.Vacuum evaporation is extremely at vacuum degree -0.095MPa for materialAmount of dry matter percent concentration is 82%, carries out vacuum cane sugar boiling and crystal under vacuum degree 120mbar, xylitol crystal is precipitated, mostIt is centrifuged 15min by 5000rpm, 80 DEG C of drying 60min obtain xylitol crystal.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the inventionMade any modifications, equivalent replacements, and improvements etc., should all be included in the protection scope of the present invention within mind and principle.