CN107098808A - The preparation method and process units of a kind of high-purity, high content normal temperature not crystalline lactic acid product - Google Patents
The preparation method and process units of a kind of high-purity, high content normal temperature not crystalline lactic acid product Download PDFInfo
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Abstract
The present invention relates to the preparation method and its device of a kind of high content, high-purity normal temperature not crystalline lactic acid product, mainly solve high content, high-pure lactic acid product normal temperature and easily crystallize, lump, it is influence storage, unfavorable the problem of use.Lactic raw material heating in vacuum is boiled and maintains a period of time to be concentrated and be dehydrated by this method first, then after concentrate and two kinds of components of distillate being cooled down respectively, again according to required lactic product content target, blent by calculating to mix or measure to add water to corresponding concentration.The present invention is in the case of without other compositions, by physical means overcome existing lactic product in packaging, storage, transport, easily crystallized using link, lump, the drawbacks of being unfavorable for chemically reacting, be difficult to conveying, production preparation process does not change the chemical property of lactic product application environment, obtained product is applied to more use environments and occasion, conveniently take, prepare, quantitative or automation is precisely conveyed, and is conducive to chemical reaction.
Description
Technical field
The present invention relates to Fine Organic Chemical product technical field, and in particular to a kind of to lactic product made from existing process
Specific aim processing is carried out, the method and process units of high content, high-purity normal temperature not crystalline lactic acid product is obtained.
Background technology
Lactic acid sterling be colourless liquid, odorlessness, can be miscible with water, ethanol, glycerine with hygroscopicity, insoluble in chloroform,
Carbon disulfide and petroleum ether, relative density 1.2060 (25/4 DEG C), refractive index nD=1.4392 (20 DEG C), 122 DEG C of boiling point
(2kPa), is heated to 190 DEG C and vaporizes and decompose at ambient pressure.Lactic acid is divided into Pfansteihl, D-ALPHA-Hydroxypropionic acid and DL-LACTIC ACID.
When lactic acid aqueous solution is concentrated into 50% by low concentration, just has and be partially converted to lactic anhydride, the production under this concentration
The normal lactic anhydride containing 10%-15% in product.Content is more than 32% (m/m) high-purity lactic acid aqueous solution, with the presence of crystal seed or
To be formed under conditions of crystal seed, DL-LACTIC ACID is below 16.8 DEG C, Pfansteihl or D-ALPHA-Hydroxypropionic acid just have crystallization or tied below 53 DEG C
The possibility of block.When not carrying out specific aim lactic product made from crystallization treatment be not below content >=93%, 25 DEG C of temperature i.e.
Crystallization, the risk of caking are occurred, this will cause to be likely to occur Crystallization Plugging in pipeline and (not kept company in extreme environment or design
The factory of heat configuration), it is impossible to ensure that product carries out normal bucket (or tank) packaging, transport, to client using making troubles or shadow
Ring using effect.Because lactic acid dissolution condition there are many uncertainties again, it is more difficult to realize using solid-state packaging and risk is bigger,
It larger can limit it and use scope.
For Surface Processing Industries such as chemical platings, the adverse effect that zone of a crystal occurs in lactic acid is bigger.Chemical nickel plating is near
Developed over 20 years, using and constantly improve and a kind of process of surface treatment technology for growing up, be widely used in plastics and prevent
The industries such as shield, anti-corrosion of metal, computer and the manufacture of sophisticated electronics mainboard.Its principle is done using the sulfate of metallic nickel
Nickel source, the reducing agent such as sodium hypophosphite dissociates and forms nickel precipitation as coating.To improve process efficiency, the increase plating of chemical plating
Layer stability, the quality of coating for ensureing a variety of application environments to greatest extent, also need to add a variety of auxiliary agents in electroplate liquid.Breast
Acid is exactly the auxiliary agent class material of wherein consumption maximum, and its mechanism of action is to make nickel sulfate water-soluble using the complexing of lactic acid
The nickel ion ionized in liquid is in homogeneously dispersed state, while its reproducibility relatively low relative to sodium hypophosphite is unlikely to make again
Established coating dissolves once again.Based on this application environment, lactic acid body is incrystallizable to require particularly important：Because objective
The crystal suspension of presence can form crystal seed effect, be unfavorable for preparing the main auxiliary material dissolving and diffusion of chemical plating.Meanwhile, even if
Few lactic acid crystallization or other the non-nickle atom crystal depositions being affected by it, can all influence and destroy quality of coating, particularly
The accurate plating piece of most chemical nickel platings is non-metallic material (plastics or epoxy resin) again, and the building ring mirror that it is surface-treated is not
It can carry out at high temperature.The industry is particularly important therefore, low temperature or normal temperature are difficult crystalline lactic acid.
Disperse purpose, the soda acid buffering effect of plating solution environment, knot in the complexing of metal ion of application environment in view of lactic acid
Close lactic acid, lactic anhydride, dilactic acid characteristic miscible with water, and lactic anhydride, dilactic acid can with system temperature and water content oneself
The slowly releasing effect that the characteristic of water-filling solution possesses, in the timing of concentration one of required total lactic acid, when plating solution is prepared containing lactic acid, lactic anhydride,
The mixture of dilactic acid is better than the pure free lactic acid of same concentrations.I.e. when the material acid of chemical plating process is selected, partially
It is good containing lactic acid, lactic anhydride, dilactic acid mixture lactic acid, when lactic acid acid value is equal, its pH is than same concentrations without specific aim
The pH of PROCESS FOR TREATMENT is low, buffering effect is reliable, Complex effect is stable.
Further according to the special nature of lactic acid, from low concentration by heat to higher concentration concentrate when, be not added with catalyst
Or other non-lactic acid materials, objectively there is also between the lactic acid molecules of part and intramolecular dehydration generation dilactic acid and lactic anhydride
The fact, and content is higher, the time is longer, ratio is bigger.And by being heated to higher temperature (50 to 190 DEG C) while coordinating true
Empty (decompression：Absolute pressure<101080Pa) improve lactic acid content (>32%) content of dilactic acid and lactic anhydride in system is caused to increase
Plus after, even if dehydrating amount equivalent is returned plus, usual environment temperature (<50 DEG C) under, it is not easy to hydrolyze in a short time before this
System content ratio, and content increase be more difficult to more greatly reply (used time is longer).Pure dilactic acid and lactic anhydride fusing point is more newborn
Acid is low, and the aqueous solution of itself and lactic mixt is less susceptible to crystallize, lumpd.
The content of the invention
Easily crystallize it is an object of the invention to solving existing high-purity and high level lactic product, influence to use not
There is provided the preparation method and process units of a kind of high-purity, high content normal temperature not crystalline lactic acid product for foot.This method has work
Skill is simple, do not introduce other impurities, product transports the advantages of using beneficial to packing and storing, is particularly suitable for chemical plating and chemistry
Synthesize industry.To achieve the above object, the technical solution adopted in the present invention is as follows：
The preparation method of a kind of high-purity, high content normal temperature not crystalline lactic acid product, comprises the following steps：(a) by raw material
Lactic acid is pumped into thermal dehydration kettle, and opening vacuum plant makes the certain vacuum of maintenance and heating in thermal dehydration kettle, treats lactic acid
Seethe with excitement and maintain that lactic acid content is measured by sampling after certain time, reach and stop heating after setting value, then into thermal dehydration kettle
Nitrogen is inputted, the vacuum state of thermal dehydration kettle is during which maintained；(b) when material temperature is less than 100 DEG C in dehydrating kettle to be heated, stop
Input nitrogen and vacuumize, empty thermal dehydration kettle and keep atmospheric pressure state, by the condensed device of lactic acid in thermal dehydration kettle
Input and blent in tank after A condensations, the lactic acid that thermal dehydration stilling goes out-water azeotropic mixture is inputted after vacuum buffer tank and condenser B
Blend in tank or individually recovery；(c) be measured by sampling blend lactic acid content in tank, by blend in tank inject amount of calculation water,
High content, high-purity normal temperature not crystalline lactic acid product are produced to target lactic acid content.
According to such scheme, material acid is pumped into after thermal dehydration kettle in step (a), heating makes the slow heating direct of lactic acid
To seething with excitement, system absolute pressure 1500-2000Pa is maintained, continuing heating makes lactic acid keep fluidized state, in 120 ± 5 DEG C of samplings
Determine lactic acid content.
According to such scheme, step (a) is middle according to required target product content requirement, when target product content is 100%
When following, the lactic acid content of measure stops heating when being more than 102% in terms of lactic acid；When target product content is more than 100%
When, the lactic acid content of measure stops heating when being more than target content more than 2% in terms of lactic acid, stops the follow-up continuous maintainer of heating
The vacuum state of system and stable certain time, then from the bottom input nitrogen a small amount of, uniform, lasting into thermal dehydration kettle,
The absolute pressure of system maintains 2000-4000Pa when being passed through nitrogen.
Stop being passed through after nitrogen according to such scheme, in step (b), the lactic acid in thermal dehydration kettle is passed through into condenser A
It is cooled to be delivered to after 45 ± 5 DEG C and blends in tank, the lactic acid that thermal dehydration stilling goes out-water azeotropic mixture is through vacuum buffer tank and cold
Condenser B is cooled to after 45 ± 5 DEG C to be delivered to and blends in tank or individually reclaim.
It is preferred that, existing scale and possess short-range molecular distillation method equipment carry out high-purity, high content production of lactic acid
Occasion, to realize high-purity, high content normal temperature not the production of crystalline lactic acid product when, in step (b) in thermal dehydration kettle
The material that lactic acid comes out by also needing by a set of short-path evaporator installed additional before condenser A, from the short-path evaporator its
In all the way condensed device B condense to input after 45 ± 5 DEG C and blend tank, another road is collected and obtains ultrapure lactic acid, can direct reuse or
As ultrapure lactic product direct marketing after being watered, the absolute pressure of the short-path evaporator maintains 50-100Pa, material evaporation temperature
50-100 DEG C of degree, thermal dehydration kettle is at least provided with two, so that alternation ensures continuous production.
According to such scheme, content >=32% of the raw material in thermal dehydration kettle in terms of lactic acid is pumped into, is gone out from tank is blent
The high-purity come, the high content normal temperature content that crystalline lactic acid product is not counted using lactic acid is 32-128%.
According to such scheme, production of lactic acid line of the material acid from head tank or factory.
It is a further object of the present invention to provide the process units of a kind of high-purity, high content normal temperature not crystalline lactic acid product,
It is characterized in that：The device includes thermal dehydration kettle, vacuum buffer tank, vacuum plant, condensing unit, blends tank and conveying
Pump, the vacuum plant is connected by pipeline with condenser B, vacuum buffer tank and thermal dehydration kettle, for thermal dehydration
Kettle vacuumizes and flows into vacuum buffer tank after ensureing the steam material come from kettle ejection condensation；The tank of blending passes through pipeline point
It is not connected with condenser A and vacuum buffer tank, the lactic raw material good for mixed processing；The condenser A other end successively with
Dehvery pump 2 is connected with thermal dehydration kettle, and thermal dehydration bottom portion is provided with gas blowpipe and valve, is set blending on tank
There is liquid inlet opening to be used to inject pure water, thermal dehydration kettle and blend tank and be respectively arranged with the dehvery pump 1 that is attached thereto and defeated
Expect pump 4, in vacuum buffer tank and blend and be additionally provided with dehvery pump 3 between tank.
According to such scheme, short-path evaporator, the short distance evaporation are also had additional between thermal dehydration kettle and condenser B
Device is connected with high-vacuum installation, and tank is blent in input to the material come out from short-path evaporator after condensed device B condensation all the way, another
Road obtains ultrapure lactic acid after collecting, and direct reuse or ultrapure lactic product direct marketing can be used as after being watered.
According to such scheme, the thermal dehydration kettle is discharged by pipeline and valve with head tank or lactic acid plant produced line
Mouth is connected.
Compared with prior art, the invention has the advantages that：
(1) end-product high content of the present invention, high-purity normal temperature not crystalline lactic acid product, substantially lactic acid, lactic anhydride and breast
The mixture of acyl lactic acid or the aqueous solution of these mixtures, and the additive of crystallization is prevented without additional, overcome existing
Lactic product packaging, storage, transport, easily crystallized using link the drawbacks of, lactic product after this treatment is in normal temperature shape
Do not crystallize or seldom crystallize substantially under state.
(2) final finished is conveniently taken, prepared, quantitative or automation is precisely conveyed.With regard to most of use environments and occasion,
The taking, prepare of same size liquid material, quantitative or Automatic Conveying, the equipment technology of dispensing are more ripe, scale of investment more
Small, accuracy is higher.
(3) chemical property of lactic product application environment is not changed.High content, high-purity normal temperature not crystalline lactic acid product
Be formed by appropriate technical process, by change fixed under normal temperature state in aqueous (0~60%) system lactic acid and lactic anhydride and
What the ratio of dilactic acid content was realized, under the conditions of most concrete application, lactic anhydride and dilactic acid pass through hydrolysis
Intrinsic (without processing) level can be returned to.
(4) chemical reaction is conducive to.Just the synthesis of the current many chemical products production grasped by raw material of lactic acid is anti-
Ying Zhong, is entirely almost using high content, high-pure lactic acid product, especially with lactate, PLA and the system that amount is larger
Medicine industry.
Brief description of the drawings
Fig. 1 is dehydrated for conventional vacuum of the present invention -- concentration method process chart；
Fig. 2 is dehydrated for conventional vacuum of the present invention -- concentration method equipment schematic diagram；
Fig. 3 is high vacuum short-range molecular distillation of the present invention -- blend method process chart；
Fig. 4 is high vacuum short-range molecular distillation of the present invention -- blend method equipment schematic diagram.
Embodiment
To make those of ordinary skill in the art fully understand technical scheme and beneficial effect, below in conjunction with specific
Embodiment is further described.
The present invention does fine chemistry industry enterprise and the professional production of lactic acid enterprise development of scale of raw material for buying lactic acid
Two sets of similar high contents, high-purity normal temperature not crystalline lactic acid product processes, are referred to as conventional vacuum dehydration -- enrichment
Method and high vacuum short-range molecular distillation -- method is blent, specifically as Figure 1-4.Compared to conventional vacuum dehydration -- concentration method is high
Vacuum short-range molecular distillation -- the principle for blending method is by the short-range molecular distillation of the thermally-stabilised level lactic acid of existing lactic acid industry production
Equipment is docked with " conventional vacuum dehydration -- concentration method " main equipment, is the auxiliary of " conventional vacuum dehydration -- concentration method "
Help equipment to be not required to cooling system, a supporting short-path evaporator is further added by thereafter.
The basic ideas of above two method are：Lactic raw material vacuum is pumped into thermal dehydration kettle, in certain vacuum degree
Lower ebuillition of heated completes the conversion of lactic acid, will then be inputted respectively after the liquid material of bottom and the condensation of the gas material on kettle top
Blend to add water in tank and mix to the final products of certain lactic acid content.Difference is, high vacuum short-range molecular distillation -- hook
Converting the liquid material of bottom in method is needed after first being evaporated through short-path evaporator, and tank is blent in input after concentrated phase is condensed, by distilling
Light component reclaim after direct reuse or after being watered as ultrapure lactic product direct marketing.Wherein, thermal dehydration kettle is bottom
F formula thermal dehydration kettles with nitrogen blowpipe, thermal dehydration kettle internal face is enamel or 2205 dual phase steels or 316L stainless steels
The material more than resistance to heated lactic acid corrosion evaluation " excellent " such as matter, the mode of heating of thermal dehydration kettle is jacket type steam or led
Hot-oil circulation is heated.The vacuum plant is the vapor jet vacuum pump of 316L materials, and it passes through condenser, vacuum buffer tank
It is connected with thermal dehydration kettle.The condenser from helix tube, tubulation, it is U-shaped in optionally, area is supporting with main equipment；It is described to connect
By tank, it is connected with vacuum system, material is with F formula thermal dehydration kettles；The cooling device, material is excellent with F formula thermal dehydration kettles
First constructed from helix tube or pipe type；The finished product blends tank, and material is matched somebody with somebody with F formula thermal dehydration kettles, volume with agent set
Set, band stirring.
As it was previously stated, being not merely pure lactic acid (chemical formula C in lactic acid solution3H6O3Mole 90.08), contain toward contact
There is dilactic acid (chemical formula C6H10O2, mole 162.16), poly- dilactic acid (chemical formula C3nH6n-2On-1, mole
90.08n-18), (chemical formula is C to lactic anhydride3H4O2, mole 72) in one or more.The measure of lactic acid content of the present invention
Method using plus alkali (1mol/L sodium hydrate aqueous solutions) saponification and quantitative scoring calculate, in saponification measuring environment each
The amount that lactic acid units and free lactic acid consume alkali (1mol/L sodium hydrate aqueous solutions) is identical, during calculating by dilactic acid,
Poly- dilactic acid, lactic anhydride are converted into the mole (i.e. in terms of lactic acid) of lactic acid, then are calculated with the lactic acid after conversion in product
Lactic acid mass fraction.So if the objective content of other structures form of the non-free lactic acid containing lactic acid units reach it is higher
Ratio, just occurs the situation that the content in terms of lactic acid is more than 100%, because the existence form of these structures containing lactic acid units
Free lactic acid (authoritative lactic acid content measure can be easily hydrolyzed to by being diluted with water under most use environment
Method is shown in GB1886.173-2016).
Embodiment 1-3 be using conventional vacuum dehydration -- concentration method production normal temperature not crystallization treatment obtain high content, it is high-purity
Spend the specific example of lactic product.
Embodiment 1
Raw material：88% (m/m) fine purification of lactic acid, 4500Kg.
By the normal temperature method that crystallization treatment does not obtain high content, high-pure lactic acid product, comprise the following steps：
A. start dehvery pump 1, material acid is once input in thermal dehydration kettle；Start what is be connected with thermal dehydration kettle
Vacuum plant, opens the cooling water of cooler B between vacuum buffer tank and vacuum plant, the pressure drop to thermal dehydration kettle
To the intermittent-heating system for opening thermal dehydration kettle during 4000Pa, feed liquid in thermal dehydration kettle is maintained to be in stable boiling-like
State, to thermal dehydration kettle in pressure be down to 2000Pa, feed temperature and rise to 122 DEG C.Stable 10min (or on having to feed temperature
During the trend of liter), stop heating, continue holding and vacuumize state.This heat time about 180min.
When being b. down to about 115 DEG C to feed temperature in thermal dehydration kettle, slowly open and lead to nitrogen toward in thermal dehydration kettle
Pressure is in 2000~4000Pa in valve, maintenance thermal dehydration kettle.When being down to 105 ± 5 DEG C to material temperature, thermal dehydration kettle is opened
Exhaust-valve, close and stop the vacuum plant being connected with thermal dehydration kettle, it is 107% (with lactic acid that lactic acid content, which is measured by sampling,
Meter), this activity time about 60min.
C. the condensed device A of thermal dehydration kettle is opened toward blending the series of valves of tank, opening condenser A cooling water, from control
System processed is set toward the feeding temperature of tank is blent for 45 ± 5 DEG C, starts delivery pump 2, and feed liquid is continued, once inputs and blends tank.
D. open vacuum buffer tank and blend the baiting valve between tank, start delivery pump 3, by what is reclaimed in vacuum buffer tank
Diluted acid once inputs and blends tank.Tank stirring is blent in startup, continues stir about 20min, stops stirring, and lactic acid content is measured by sampling
About 98% (m/m).Calculated according to amount toward tank plus pure water 816Kg is blent, be again stirring for about 20min, 45 DEG C of feed temperature.Sampling is surveyed
It is 80.01% to determine lactic acid content.
E. open and blend tank bottom baiting valve, start delivery pump 4, product is inputted into bulking system.
F. after filling 80% (m/m) content specification the special lactic product 4900Kg of chemical plating, total recovery about 99.0%.
Embodiment 2
The preparation of 100% (m/m) content normal temperature not crystalline lactic acid.
Crystalline lactic acid not can be widely applied to chemical synthesis, pharmacy, chemical plating, food, drink to 100% (m/m) content normal temperature
Nearly all industries for being applied to lactic acid, especially esterification and perfume synthesis such as material.Be diluted with water certain concentration its with
The special lactic acid effect of chemical plating is identical, while have again, storage is convenient, save freight, one advises (lattice) multi-purpose advantage.
Raw material：93% (m/m) fine purification of lactic acid, 4500Kg.
A. start dehvery pump 1, material acid is once inputted in thermal dehydration kettle；It is true that startup is connected with thermal dehydration kettle
Empty device, opens the cooling water of cooler B between surge tank and vacuum plant, to thermal dehydration kettle in pressure be down to
During 4000Pa, the indirectly heat system of thermal dehydration kettle is opened, feed liquid is maintained in thermal dehydration kettle in stable fluidized state,
Pressure is down to 2000Pa, feed temperature and rises to 122 DEG C in thermal dehydration kettle.Stable 10min (or have rising to feed temperature
During trend), stop heating, continue holding and vacuumize state.This heat time about 140min.
When being b. down to about 115 DEG C to feed temperature in thermal dehydration kettle, slowly open and lead to nitrogen toward in thermal dehydration kettle
Pressure is in 2000~4000Pa in valve, maintenance thermal dehydration kettle.When being down to 105 ± 5 DEG C to material temperature, thermal dehydration kettle is opened
Exhaust-valve, close and stop the vacuum plant being connected with thermal dehydration kettle, sampling and measuring content is 109% (in terms of lactic acid),
This activity time about 90min.
C. thermal dehydration kettle is opened through cooler A toward the series of valves of tank is blent, and opens cooler A cooling water, from control
System processed is set toward the feeding temperature of tank is blent for 45 ± 5 DEG C, starts delivery pump 2, and feed liquid is continued, once inputs and blends tank.
D. open vacuum buffer tank and blend the baiting valve between tank, start delivery pump 3, by vacuum buffer tank reclaim it is dilute
Once tank is blent in input to acid.Tank stirring is blent in startup, continues stir about 20min, stops stirring, and content about 103% is measured by sampling
(m/m).Calculated according to amount toward tank plus pure water 112.8Kg is blent, be again stirring for about 20min, 45 DEG C of feed temperature.Breast is measured by sampling
Acid content is 100.20%.
E. open and blend tank bottom baiting valve, start delivery pump 4, product is inputted into bulking system.
F. after filling 100% (m/m) content normal temperature not crystalline lactic acid product 4151Kg, total recovery about 99.4%.
Embodiment 3
The preparation of 107% (m/m) content normal temperature not crystalline lactic acid
Crystalline lactic acid not can be used for the industries such as scientific experiment, chemical synthesis, pharmacy to 107% (m/m) content normal temperature.
Raw material：93% (m/m) fine purification of lactic acid, 4500Kg.
A. start dehvery pump 1, material acid is once inputted in thermal dehydration kettle；It is true that startup is connected with thermal dehydration kettle
Empty device, opens the cooling water of cooler B between surge tank and vacuum plant, to thermal dehydration kettle in pressure be down to
During 4000Pa, the indirectly heat system of thermal dehydration kettle is opened, feed liquid is maintained in thermal dehydration kettle in stable fluidized state,
Pressure is down to 2000Pa, feed temperature and rises to 122 DEG C in thermal dehydration kettle.Stable 10min (or have rising to feed temperature
During trend), stop heating, continue holding and vacuumize state.This heat time about 140min.
When being b. down to about 115 DEG C to feed temperature in thermal dehydration kettle, slowly open and lead to nitrogen toward in thermal dehydration kettle
Pressure is in 2000~4000Pa in valve, maintenance thermal dehydration kettle.When being down to 105 ± 5 DEG C to material temperature, thermal dehydration kettle is opened
Exhaust-valve, close and stop the vacuum plant being connected with thermal dehydration kettle, sampling and measuring content is 108% (in terms of lactic acid),
This activity time about 90min.
C. thermal dehydration kettle is opened through cooler A toward the series of valves of tank is blent, and opens cooler A cooling water, from control
System processed is set toward the feeding temperature of tank is blent for 45 ± 5 DEG C, starts delivery pump 2, and feed liquid is continued, once inputs and blends tank.
D. calculated according to amount toward tank plus pure water 36Kg is blent, startup blends tank stirring, continues stir about 20min, stops stirring,
Content about 107.0% (m/m) is measured by sampling.
E. open and blend tank bottom baiting valve, start delivery pump 4, product is inputted into bulking system.
F. vacuum buffer tank bottom baiting valve is opened, starts delivery pump 3, vacuum buffer tank diluted acid is once exported and contained
Dress, weighing, obtain the dilute lactic acid 123.5Kg of 26% content.
G. after filling 107% (m/m) content normal temperature not crystalline lactic acid product 3725Kg, total recovery about 99.6%.
Embodiment 4
Embodiment 4 be use high vacuum short-range molecular distillation -- blend method production normal temperature not crystallization treatment obtain high content,
The specific example of high-pure lactic acid product.
For can accurate validation high vacuum short-range molecular distillation -- the effect of method technique is blent, has used a set of former main body to be
6m2Short-range molecular distillation device replace scale production of lactic acid factory short-path distillation system and high vacuum short distance molecule to steam
Evaporate -- the thermal dehydration tank charging aperture docking of method is blent, i.e., by light component (the refining agent breast of foregoing short-range molecular distillation device
Acid) without cooling equality of temperature input thermal dehydration tank (thering are two thermal dehydration tanks arranged side by side to replace splicing during continuous production).Meanwhile,
In high vacuum short-range molecular distillation -- method technique thermal dehydration tank is blent with blending between tank increase and docking one with two ends
6m2Short-path evaporator carries out multicycle application.
Raw material：Fresh (depart from from production line and the be less than 8 hours) food-grade ordered from domestic fermentation method production of lactic acid enterprise
30 tons of Pfansteihl product, lactic acid content 80%.
One representational complete cycle of tool application is as follows：
A. start short-range molecular distillation device, material acid is inputted by code, to keeping short-path evaporator when working well
50~100Pa of system (absolute pressure), 80~100 DEG C of vapo(u)rizing temperature (concentrated phase temperature), 50~55 DEG C of light component temperature directly are entered to add
Heat dehydration kettle A improves thermal dehydration kettle B to target scale.
B. the vacuum plant being connected with thermal dehydration kettle A is started, opening surge tank is cold with vacuum plant intercooler
But water, to thermal dehydration kettle A (or B) in pressure when being down to 4000Pa, open the indirectly heat system of thermal dehydration kettle, dimension
Feed liquid in thermal dehydration kettle is held in stable fluidized state, to thermal dehydration kettle in pressure be down to 2000Pa, feed temperature and rise to
122℃.Stable 10min when on the rise (or to feed temperature), stops heating, continues holding and vacuumize state.This adds
About 60min of hot time.
C. start the vacuum plant being connected with short-path evaporator after thermal dehydration kettle A (or B) and start short distance by code
Evaporator, while opening thermal dehydration kettle A (or B) bottom baiting valve, starting delivery pump 2, regulation control material is with appropriate flow velocity
Enter short-path evaporator, maintain system vacuum in 50~100Pa, evaporating temperature (concentrated phase temperature) in 50~100 DEG C of lasting distillations
Operation.Start delivery pump 4 and delivery pump 5 in good time, the dress for the ultrapure lactic acid input for distilling collecting tank being specified with appropriate flow velocity
Put；Tank is blent into the feed liquid input of concentrated phase pans, into the material temperature of tank is blent for 45 ± 5 DEG C, content, which is measured by sampling, is
128%.Recovery rate is the 80% of total feed.
D. according to required normal temperature not crystalline lactic acid product objective content, using it is directly filling or respectively by add diluted acid,
Add pure water, while the mode for adding diluted acid and pure water carries out content regulation, obtain the high-purity of 32~128% any contents
Normal temperature not crystalline lactic acid product is spent, about 15.4 tons of 100% product is converted into.
E. after the processing completely of batch raw material, equivalent about 3.85 tons of 88% (m/m) the content lactic acid of ultrapure lactic product is counted to obtain；
F. scale lactic acid factory is turned into short-range molecular distillation equipment production fine purification of lactic acid by food grade lactic acid raw material
Maturation and setting process, one time yield can reach 80% or so or more, herein by 80% setting technology controlling and process (residue
Amount accounts for raw material total amount 17%, loss and accounted for 3%).
G. equip the fine purification of lactic acid produced by the f short-range molecular distillations to input after thermal dehydration kettle, obtain normal temperature not
The yield of crystalline lactic acid product be into thermal dehydration kettle total amount about 80%, ultrapure lactate yield be into thermal dehydration kettle
About the 19% of total amount, loss accounts for 1%.
To be fully understood by the actual performance of high content produced by the present invention, high-purity normal temperature not crystalline lactic acid product, we
Crystallization contrast test has been carried out at different temperatures to the lactic product of separate sources, it is as a result as shown in the table.
The different lactic product crystallization comparative test result tables of table 1
Explanation："None" represents to have no crystallization；" having " indicates to crystallize or crystallized obvious；" caking " represent all crystallization without
Seeing has mother liquor.
Claims (10)
1. the preparation method of a kind of high-purity, high content normal temperature not crystalline lactic acid product, it is characterised in that comprise the following steps：
(a) material acid is pumped into thermal dehydration kettle, opening vacuum plant makes the certain vacuum of the interior maintenance of thermal dehydration kettle and add
Heat, is measured by sampling lactic acid content after lactic acid seethes with excitement and maintains certain time, reaches and stops heating after setting value, then to heating
Input nitrogen in dehydrating kettle, during which maintains the vacuum state of thermal dehydration kettle；(b) material temperature is less than 100 DEG C in dehydrating kettle to be heated
When, stop input nitrogen and vacuumize, empty thermal dehydration kettle and keep atmospheric pressure state, the lactic acid in thermal dehydration kettle is passed through
Input and blent in tank after condenser A condensations, the lactic acid that thermal dehydration stilling goes out-water azeotropic mixture is through vacuum buffer tank and condenser B
Input is blent in tank or individually recovery afterwards；(c) it is measured by sampling and blends lactic acid content in tank, by injects amount of calculation in tank to blending
Water, produce high content, high-purity normal temperature not crystalline lactic acid product to target lactic acid content.
2. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：Material acid is pumped into after thermal dehydration kettle in step (a), heating lactic acid is slowly heated up until boiling, maintains system
Absolute pressure 1500-2000Pa, continuing heating makes lactic acid keep fluidized state, and lactic acid content is measured by sampling at 120 ± 5 DEG C.
3. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：According to required target product content requirement, when target product content is below 100%, the lactic acid of measure in step (a)
Content stops heating when being more than 102% in terms of lactic acid；When target product content is more than 100%, the lactic acid content of measure with
Lactic acid meter stops heating when being more than target content more than 2%, stops continuing the vacuum state of holding system after heating and stablizes one
Fix time, then from the bottom input nitrogen a small amount of, uniform, lasting into thermal dehydration kettle, system is absolute when being passed through nitrogen
Pressure maintains 2000-4000Pa.
4. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：Stop being passed through after nitrogen in step (b), the lactic acid in thermal dehydration kettle is cooled to by condenser A defeated after 45 ± 5 DEG C
Deliver to and blend in tank, the lactic acid that thermal dehydration stilling goes out-water azeotropic mixture is cooled to 45 ± 5 DEG C through vacuum buffer tank and condenser B
After be delivered to blend in tank or individually reclaim.
5. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：In existing scale and possess short-range molecular distillation method equipment and carry out high-purity, the occasion of high content production of lactic acid, be real
Lactic acid in the production of existing high-purity, high content normal temperature not crystalline lactic acid product, step (b) in thermal dehydration kettle is by condensing
Also needed before device A by a set of short-path evaporator installed additional, the material wherein all the way condensed device B come out from the short-path evaporator
Tank is blent in condensation to input after 45 ± 5 DEG C, and another road is collected and obtains ultrapure lactic acid, can direct reuse or after being watered as ultrapure
Lactic product direct marketing, the absolute pressure of the short-path evaporator maintains 50-100Pa, and 50-100 DEG C of material evaporation temperature, heating is de-
Water kettle is at least provided with two, so that alternation ensures continuous production.
6. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：Content >=32% of the raw material in thermal dehydration kettle in terms of lactic acid is pumped into, high-purity, high content from tank is blent out
The normal temperature content that crystalline lactic acid product is not counted using lactic acid is 32-128%.
7. the preparation method of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：Production of lactic acid line of the material acid from head tank or factory.
8. the process units of a kind of high-purity, high content normal temperature not crystalline lactic acid product, it is characterised in that：The device includes heating
Dehydrating kettle, vacuum buffer tank, vacuum plant, condensing unit, blend tank and dehvery pump, the vacuum plant by pipeline with it is cold
Condenser B, vacuum buffer tank and thermal dehydration kettle are connected, for the steaming for vacuumizing and ensureing to come from kettle ejection to thermal dehydration kettle
Vacuum buffer tank is flowed into after the condensation of vapour material；The tank of blending is connected with condenser A and vacuum buffer tank respectively by pipeline,
The lactic raw material good for mixed processing；The condenser A other end is connected with dehvery pump 2 and thermal dehydration kettle successively, in heating
Dehydrating kettle bottom is provided with gas blowpipe and valve, and liquid inlet opening is provided with tank for injecting pure water blending, is heated de-
Water kettle and blend tank and be respectively arranged with the dehvery pump 1 and dehvery pump 4 being attached thereto, in vacuum buffer tank and blend between tank also
It is provided with dehvery pump 3.
9. the process units of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, its feature
It is：Short-path evaporator, the short-path evaporator and high-vacuum installation phase are also had additional between thermal dehydration kettle and condenser B
Even, tank is blent in input to the material come out from short-path evaporator after condensed device B condensation all the way, and another road obtains ultrapure breast after collecting
Acid, direct reuse or can be used as ultrapure lactic product direct marketing after being watered.
10. the process units of a kind of high-purity according to claim 1, high content normal temperature not crystalline lactic acid product, it is special
Levy and be：The thermal dehydration kettle is connected by pipeline and valve with head tank or lactic acid plant produced line discharging opening.
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| CN108689833A (en) * | 2018-06-01 | 2018-10-23 | 安徽恒星制药有限公司 | A kind of high-pure lactic acid preparation method of stabilization |
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