CN108774132A - A kind of process units and method of propylene-glycol diacetate - Google Patents
A kind of process units and method of propylene-glycol diacetate Download PDFInfo
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- CN108774132A CN108774132A CN201810928275.XA CN201810928275A CN108774132A CN 108774132 A CN108774132 A CN 108774132A CN 201810928275 A CN201810928275 A CN 201810928275A CN 108774132 A CN108774132 A CN 108774132A
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- propylene
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- glycol diacetate
- methyl ether
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/56—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
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Abstract
The present invention relates to technical field of fine chemical production, specifically disclose a kind of process units and method of propylene-glycol diacetate, side take-off cooler, decoloration kettle, filter pressing pump and filter device are additionally arranged in propylene glycol methyl ether acetate production equipment, the input terminal of side take-off cooler is connected to the middle part of vacuum rectification tower, the output end of side take-off cooler is connected to decoloration kettle, the bottom of decoloration kettle is connected to the filter pressing pump, and the outlet of filter pressing pump is connected to filter plant.The present invention increases side take-off cooler in propylene glycol methyl ether acetate production system, will relative to the higher ingredient propylene-glycol diacetate of propylene glycol methyl ether acetate boiling point as heavy constituent during rectification under vacuum by side take-off, by qualified propylene-glycol diacetate is obtained by the reaction, the waste liquid generated in propylene glycol methyl ether acetate production process is reasonably utilized, reduce the discharge of heavy constituent, while also improving the content of propylene glycol methyl ether acetate product.
Description
Technical field
It is specifically a kind of using propylene glycol methyl ether acetate production dress the invention belongs to technical field of fine chemical production
Set the process units and method of by-product propylene-glycol diacetate.
Background technology
Propylene glycol methyl ether acetate is the less toxic advanced industrial solvent of function admirable, is had to polarity and nonpolar substance
Very strong solvability, is suitable for the solvent of high-grade paint, the various polymer of ink, including amino methyl acid esters, vinyl, poly-
Ester, cellulose ethanoate, alkyd resin, acrylic resin, epoxy resin and nitrocellulose etc..Wherein, propylene glycol monomethyl ether third
Acid esters is solvent best in coating, ink, is suitable for unsaturated polyester (UP), polyurethane based resin, acrylic resin, epoxy resin
Deng.
According to traditional propylene glycol methyl ether acetate product processes, mainly existed with raw material propylene glycol monomethyl ether and acetic acid
The mixture of synthesizing propylene glycol monomethyl ether acetic acid esters under acidic catalyst effect is not engaged in the third of reaction using pretreatment removing
Crude product is finally entered in finished product rectifying column and is decolourized and purified by glycol methyl ether and acetic acid, products obtained therefrom propylene glycol first
The product quality content of ether acetic acid ester is 99.5% or more, substantially conforms to the requirement of HG/T3940-2007 standards.But with market
Compete it is more and more fierce, it is also higher and higher to the purity requirement of product, under the premise of not increasing material consumption and energy consumption, improve product
Purity will be that all manufacturers are constantly pursued.And qualitative analysis is done by the impurity to finished product and is learnt, influence product purity
The main reason for attach most importance to constituent content, by 80% predominantly propylene-glycol diacetate of impurity known to chromatography, so such as
Fruit is controlled effectively to heavy constituent, or continuously heavy constituent can be discharged from system, then can improve finished product well
Purity.
Due to the preceding process of propylene glycol methyl ether acetate production, i.e., in propylene glycol monomethyl ether production process --- etherification reaction meeting
The a small amount of propylene glycol of by-product, and this impurity can not reject in propylene glycol monomethyl ether purification process, subsequently then as finished product enters
Esterification process occurs esterification with acetic acid, generates propylene-glycol diacetate；In addition in esterification reaction process, normally
The propylene glycol methyl ether acetate generated is reacted under the conditions of acidic catalyst effect and certain temperature, continues to send out with excessive acetic acid
Raw reaction, generates propylene-glycol diacetate.There are both side reactions, and propylene glycol methyl ether acetate is caused to produce in process of production
The heavy constituent (propylene-glycol diacetate boiling point is 190.5 DEG C, and the boiling point of propylene glycol methyl ether acetate is 149 DEG C) of raw more amount,
It is 0.5% that heavy constituent, which accounts for about final product quality score, this invisible material consumption for increasing finished product.
Using current conventional pressure relief distillation process, such as attached drawing 1, the equipment needed has：1- reboilers, 2- finished products decompression essence
Evaporate tower, 3- heavy constituent collecting tanks, 4- overhead condensers, 5- return tanks, 6- reflux pumps.Using the conventional pressure relief rectifying side of attached drawing 1
Formula, finished product enter the middle part of finished product rectifying column 2 by flowmeter, and Tower System is depressurized by vacuum pump, tower reactor reboiler 1
It is heated by steam, thick finished product, which enters in tower, to be heated, and top gaseous phase is then condensed by overhead condenser 4, and condensate liquid then enters
In return tank 5, reflux operation is carried out by reflux pump 6, control reflux ratio is 1:1~1:0.5 is advisable, and waits for that finished product sampling is qualified,
When i.e. mass content reaches 99.5% or more, finished product is produced.Due to there is 0.5% heavy constituent in thick finished product, then with rectifying
It constantly carries out, heavy constituent is accumulated in tower reactor, when tower reactor liquid level is higher, then periodically carries out being discharged into tower bottoms to tower bottoms
In tank 3, after tower bottoms cooling, is packed, waste liquid stove is sent to carry out burning disposal.
By analyzing above it is found that according to traditional rectification process, the finished product content of propylene glycol methyl ether acetate being capable of base
Originally meet the standard requirement of HG/T3940-2007, i.e. final product quality content is more than 99.5%, but does not have on the market very strong
Competitiveness.If heavy constituent can continuously be produced from system, this is virtually in the case where increasing seldom equipment investment
The content that product impurity can be reduced, to achieve the purpose that improve product purity.Additionally, due to matter of the heavy constituent in finished product
It is 0.5% to measure accounting, and according to 50,000 tons/year of yield meter, then waste liquid amount is 250 tons/year.It is therefore necessary to study a kind of device
Method handles heavy constituent waste liquid, on the one hand reduces the processing cost of environmental protection aspect, in addition if can turn waste into wealth, nothing
Shape increases value-added content of product.
Invention content
Propylene glycol methyl ether acetate process units by-product propylene-glycol diacetate is utilized the object of the present invention is to provide a kind of
Device and method, the heavy constituent generated in propylene glycol methyl ether acetate distillation process is handled, to obtain purity compared with
High propylene-glycol diacetate has effectively handled the heavy constituent tar in propylene glycol methyl ether acetate production process, has reduced
The generation of waste liquid simultaneously reduces processing cost.
In order to solve the above technical problems, the present invention provides a kind of process units of propylene-glycol diacetate, including boil again
Device, vacuum rectification tower, overhead condenser, return tank and reflux pump, the vacuum rectification tower are equipped with material inlet, the decompression
The bottom of rectifying column is connected to the bottom of the reboiler, and the top of the reboiler is connected to the vacuum rectification tower, described
The tower top of vacuum rectification tower is connected to overhead condenser, and the discharge port of the overhead condenser is connected to the return tank, described
The input terminal of reflux pump is connected to the return tank, and the output end of the reflux pump is connected to the top of the vacuum rectification tower；
The process units further includes side take-off cooler, decolourize kettle, filter pressing pump and filter plant, the side take-off cooler
Input terminal is connected to the middle part of the vacuum rectification tower, and the output end of the side take-off cooler is connected to the decoloration kettle,
The bottom of the decoloration kettle is connected to the filter pressing pump, and the outlet of the filter pressing pump is connected to the filter plant.
Further, side take-off flowmeter is equipped between the side take-off cooler and the decoloration kettle.
Preferably, the bottom of the vacuum rectification tower is connected with heavy constituent collecting tank.
Further, also in parallel on the pipeline that the reflux pump is connected to vacuum rectification tower to be equipped with propylene glycol methyl ether acetate
Discharge line, the propylene glycol methyl ether acetate discharge line are equipped with finished product and produce flowmeter.
Specifically, the filter plant is connected to the top of decoloration kettle by return duct, and the bottom of the filter plant is set
There is propylene-glycol diacetate discharge line.
Specifically, the bottom of the heavy constituent collecting tank is equipped with heavy constituent discharge pipe.
The present invention also provides a kind of production methods of propylene-glycol diacetate, are as follows：
S1, rectification under vacuum will be entered from the middle part of vacuum rectification tower by the de- propylene glycol methyl ether acetate crude product gently handled
Tower carries out rectification under vacuum, and propylene glycol methyl ether acetate crude product heated by reboiler by steam, the gas phase in vacuum rectification tower into
Enter tower top, top gaseous phase is condensed into condensate liquid by condenser, and condensate liquid enters in return tank, flows back by reflux pump, instead
Multiple cycle；
S2, extraction progress chromatography is sampled to propylene glycol methyl ether acetate finished product, when finished product content is more than 99.5%,
Finished product extraction is controlled, by taking 50,000 tons/year of production capacity as an example (the same below), then finished product extraction flow is about 7.5m3/h；Start side line
Cooler is produced, the heavy constituent generated in vacuum rectification tower is entered into side take-off cooler according to heavy constituent total amount in finished product
Accounting is 0.5%, i.e., heavy constituent side take-off flow is less than 0.0375m3/ h is advisable；
S3, heavy constituent after cooling is entered into decoloration kettle, when heavy constituent accounts for the 60%-70% of kettle internal volume in the kettle that decolourizes
Activated carbon is added and is stirred decoloration；
S4, the destainer after decoloration is entered to filter pressing pump progress press filtration；
S5, it the heavy constituent after press filtration is entered into filter device is filtered, constantly recycle, until obtaining content > 95%,
Color number is less than 10 propylene-glycol diacetate.
Specifically, tower top pressure is less than 5Kpa, reflux ratio 1 in the S1：1~1:0.5, the tower bottoms of vacuum rectification tower
Phase temperature is 165~170 DEG C.
Further, the mass ratio that activated carbon accounts for heavy constituent in decoloration kettle in the S3 is 1%~3%, and mixing time is
0.5~1h.
Further, the method further includes arranging the heavy constituent in tower when tower liquid level is up to 80% in vacuum rectification tower
Into heavy constituent collecting tank.
The beneficial effects of the invention are as follows：The present invention increases side take-off cooling in propylene glycol methyl ether acetate production system
Device, do not influence propylene glycol methyl ether acetate production in the case of, will relative to propylene glycol methyl ether acetate boiling point it is higher at
Point propylene-glycol diacetate as heavy constituent during rectification under vacuum by side take-off, by qualification is obtained by the reaction the third two
The waste liquid generated in propylene glycol methyl ether acetate production process is reasonably utilized in alcohol diacetate esters, reduces the row of heavy constituent
It puts, while also improving the content of propylene glycol methyl ether acetate product.
Description of the drawings
It, below will be to required in embodiment or description of the prior art in order to illustrate more clearly of technical scheme of the present invention
The attached drawing used is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, right
For those of ordinary skill in the art, without creative efforts, it can also be obtained according to these attached drawings
Its attached drawing.
Fig. 1 is the process units structure chart of propylene glycol methyl ether acetate traditional in background technology；
Fig. 2 is the process units structure chart of propylene-glycol diacetate of the present invention.
In figure：1- reboilers, 2- vacuum rectification towers, 3- heavy constituent collecting tanks, 4- overhead condensers, 5- return tanks, 6- are returned
Stream pump, 7- side take-off coolers, 8- decolourize kettle, 9- filter pressing pumps, 10- filter plants, 11- side take-off flowmeters, 12- the third two
Alcohol methyl ether acetate discharge line, 13- finished products produce flowmeter, 14- propylene-glycol diacetate discharge lines, 15- heavy constituents row
Outlet pipe.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art obtained under the premise of not making creative work it is all its
His embodiment, shall fall within the protection scope of the present invention.
It is a kind of process units of propylene-glycol diacetate as shown in Figure 2 in technical solution disclosed by the invention, packet
Reboiler 1, vacuum rectification tower 2, overhead condenser 4, return tank 5 and reflux pump 6 are included, the middle part of the vacuum rectification tower 2 is equipped with
Material inlet, the bottom of the vacuum rectification tower 2 are connected to the bottom of the reboiler 1, the top of the reboiler 1 with it is described
Vacuum rectification tower 2 is connected to, and the tower top of the vacuum rectification tower 2 is connected to overhead condenser 4, the discharging of the overhead condenser 4
Mouth is connected to the return tank 5, and the input terminal of the reflux pump 6 is connected to the return tank 5, the output end of the reflux pump 6
It is connected to the top of the vacuum rectification tower 2, it is also in parallel on the pipeline that the reflux pump 6 is connected to vacuum rectification tower 2 to be equipped with third
Glycol methyl ether acetate discharge line 12, the propylene glycol methyl ether acetate discharge line 12 are equipped with finished product and produce flowmeter
13；
The bottom of the vacuum rectification tower 2 is connected with heavy constituent collecting tank 3, and the bottom of the heavy constituent collecting tank 3 is equipped with
Heavy constituent discharge pipe 15, heavy constituent are discharged into heavy constituent collecting tank 3, after cooling, by heavy constituent discharge pipe 15 be discharged into
Enter waste liquid stove to be handled；
The process units further includes side take-off cooler 7, decoloration kettle 8, filter pressing pump 9 and filter plant 10, the side
The input terminal of line extraction cooler 7 is connected to the middle part of the vacuum rectification tower 2, and the position of the side take-off cooler 7 exists
The lower section of decompression 2 material inlet of rectifying column, during distributor designs in this rectifying column, collecting annular groove can be to upper
The liquid phase of layer filler is collected, so only needing the trepanning at the collection annular groove of tower reactor packing layer suitable position, increases side line
Floss hole is the purpose that can reach extraction suitable ingredients, and the collection ring groove position selected in this example is gating location down 2
~3 packing layer positions do not influence the distribution of tower rectifying section, reduce the possibility of extraction major product propylene glycol methyl ether acetate in this way
Property, in addition to ensure there is 1~2 each packing layer below selected location, prevent the heavy constituent quilt than propylene-glycol diacetate weight in this way
Extraction；
The output end of the side take-off cooler 7 is connected to the decoloration kettle 8, the side take-off cooler 7 and institute
It states and is equipped with side take-off flowmeter 11 between decolourizing kettle 8, the bottom of the decoloration kettle 8 is connected to the filter pressing pump 9, the press filtration
The outlet of pump 9 is connected to the filter plant 10, and the filter plant 10 is connected to the top of decoloration kettle 8 by return duct, institute
The bottom for stating filter plant 10 is equipped with propylene-glycol diacetate discharge line 14.
The invention also discloses a kind of production methods of propylene-glycol diacetate, are as follows：
S1, rectification under vacuum will be entered from the middle part of vacuum rectification tower by the de- propylene glycol methyl ether acetate crude product gently handled
Tower carries out rectification under vacuum, and propylene glycol methyl ether acetate crude product heated by reboiler by steam, the gas phase in vacuum rectification tower into
Enter tower top, tower top pressure is less than 5Kpa, and top gaseous phase is condensed into condensate liquid by condenser, and condensate liquid enters in return tank, passes through
Reflux pump flows back, reflux ratio 1：1~1:0.5, tower reactor liquidus temperature is 165~170 DEG C, iterative cycles；
S2, when every operating index reaches the requirement in S1 in vacuum rectification tower, to propylene glycol methyl ether acetate finished product
Sampling extraction carries out chromatography, when finished product content is more than 99.5%, control finished product extraction, by taking 50,000 tons/year of production capacity as an example
(the same below), then finished product extraction flow is about 7.5m3/h；Start side take-off cooler, the weight that will be generated in vacuum rectification tower
Component enters side take-off cooler, in the accounting of finished product is 0.5% according to heavy constituent total amount, i.e. heavy constituent side take-off flow
To be less than 0.0375m3/ h is advisable；
S3, heavy constituent after cooling is entered into decoloration kettle, when heavy constituent accounts for the 60%-70% of kettle internal volume in the kettle that decolourizes
Activated carbon is added and is stirred decoloration, the mass ratio that activated carbon accounts for heavy constituent in decoloration kettle is 1%~3%, mixing time 0.5
~1h；
S4, the destainer after decoloration is entered to filter pressing pump progress press filtration；
S5, it the heavy constituent after press filtration is entered into filter device is filtered, constantly recycle, until obtaining content > 95%,
Color number is less than 10 propylene-glycol diacetate.
S6, when tower liquid level is up to 80% in vacuum rectification tower, by much higher than propylene-glycol diacetate of other boiling points in tower
The heavy constituent of polymers accumulation discharges into heavy constituent collecting tank.
Comparative example 1
1) it as shown in Fig. 1, enters and subtracts by flowmeter by the de- thick finished product of propylene glycol methyl ether acetate gently handled
Press the middle part of rectifying column 2, rectifying tower system depressurized by vacuum pump, the thick finished product liquid part of propylene glycol methyl ether acetate into
Enter by entering vacuum rectification tower 2 after steam heating vaporization in reboiler 1, top gaseous phase is then condensed by overhead condenser 4, is condensed
Liquid then enters in return tank 5, and reflux operation is carried out by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, control tower top pressure is 1 less than 5Kpa (absolute pressure), control reflux ratio:1~1:0.5, control tower bottoms phase temperature is 165
~170 DEG C；
2) in 1) rectifying column indices meet after normal range value, finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is more than 99.5%, control finished product extraction is 7.5m3/h；
3) after about running 24 hours, the analysis result of finished product is analyzed, finished product content is maintained 99.5% or more；
4) by this present embodiment without side take-off, heavy constituent then carries out intermittent discharge according to treating column liquid level, about 3 days
Discharge is primary, once about 2.5 tons, so being run according to this embodiment, it is known that the production capacity of propylene-glycol diacetate is 0 ton/year, weight
Component discharge capacity is 250 tons/year, and the content of propylene glycol methyl ether acetate is 99.5%.
Specific embodiments of the present invention 1：
1) it as shown in Fig. 2, enters and subtracts by flowmeter by the de- thick finished product of propylene glycol methyl ether acetate gently handled
Press the middle part of rectifying column 2, rectifying tower system depressurized by vacuum pump, the thick finished product liquid part of propylene glycol methyl ether acetate into
Enter by entering vacuum rectification tower 2 after steam heating vaporization in reboiler 1, top gaseous phase is then condensed by overhead condenser 4, is condensed
Liquid then enters in return tank 5, and reflux operation is carried out by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, control tower top pressure is 1 less than 5Kpa (absolute pressure), control reflux ratio:1~1:0.5, control tower bottoms phase temperature is 165
~170 DEG C；
2) in 1) rectifying column indices meet after normal range value, finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is more than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened, is adopted by/h at this time
Go out after heavy constituent propylene-glycol diacetate to carry out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 press filtration of filter pressing pump again
Finished product propylene-glycol diacetate is obtained by filtration；According to heavy constituent total amount finished product accounting be 0.5%, with 50,000 tons/year of production capacity
For (the same below), then when finished product extraction flow be about 7.5m3/ h, thus control heavy constituent side take-off flow be less than
0.0375m3/ h is advisable, and first control side take-off flow is 0.01m herein3/h.To side take-off component sampling analysis, by color
The content of propylene-glycol diacetate known to spectrum analysis is 96% or more, and color number is No. 50；
3) after about running 24 hours, the analysis result of finished product is analyzed, finished product content 99.5%, illustrate this process at
Positive effect is not played in the purity raising of product；
4) 8 interior extraction heavy constituent of kettle to be decolourized, which accounts for about the 60~70% of kettle internal volume, is advisable, and proceeds by decoloration and press filtration
Operation；
5) after activated carbon being added in decoloration kettle 8, stirring is opened, is about stirred 30~60 minutes, guarantee activated carbon is in a liquid
It suspends uniform, is then turned on filter pressing pump 9, press filtration is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
Being less than 10 to product color number is advisable.To press filtration product carry out content analysis, it is known that the content of propylene-glycol diacetate be 96% with
On.
6) it is 0.01m by side take-off in this present embodiment3/ h, so being run according to this embodiment, it is known that propylene glycol two
The production capacity of acetic acid esters is 72 tons/year of 0.01 × 24 × 300 ≈, and tar emission amount is 250-72=178 tons/year (assuming that density is
1g/ml), the product content of major product is 99.55%, and the product content of gained byproduct propylene-glycol diacetate is 96%.
Specific embodiment 2：
1) it as shown in Fig. 2, enters and subtracts by flowmeter by the de- thick finished product of propylene glycol methyl ether acetate gently handled
Press the middle part of rectifying column 2, rectifying tower system depressurized by vacuum pump, the thick finished product liquid part of propylene glycol methyl ether acetate into
Enter by entering vacuum rectification tower 2 after steam heating vaporization in reboiler 1, top gaseous phase is then condensed by overhead condenser 4, is condensed
Liquid then enters in return tank 5, and reflux operation is carried out by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, control tower top pressure is 1 less than 5Kpa (absolute pressure), control reflux ratio:1~1:0.5, control tower bottoms phase temperature is 165
~170 DEG C；
2) in 1) rectifying column indices meet after normal range value, finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is more than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened, is adopted by/h at this time
Go out after heavy constituent propylene-glycol diacetate to carry out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 press filtration of filter pressing pump again
Finished product propylene-glycol diacetate is obtained by filtration into filter device 10；Control side take-off flow is 0.02m herein3/h.Offside
Line produces component sampling analysis, and the content by propylene-glycol diacetate known to chromatography is 96% or more, is contained in this ingredient
Propylene glycol methyl ether acetate is within 0.1%, and color number is No. 50；
3) after about running 24 hours, the analysis result of finished product is analyzed, finished product content 99.7%, illustrate this process at
The purity of product, which improves, plays positive effect (content of comparison 99.5%).
4) the interior extraction heavy constituent of kettle to be decolourized accounts for about kettle internal volume is advisable for 60~70%, proceeds by decoloration and press filtration behaviour
Make；
5) after activated carbon being added in decoloration kettle 8, stirring is opened, about stirring 30~60 minutes, ensures activated carbon in liquid
It is middle to suspend uniform, it is then turned on filter pressing pump, press filtration is carried out to destainer, is constantly recycled, with specific reference to 3 sampling analysis of sample point,
Obtain product color number is advisable less than 10.Content analysis is carried out to press filtration product, it is known that the content of propylene-glycol diacetate is 96%
(about contain 1% propylene glycol methyl ether acetate) above；
6) it is 0.02m by side take-off in this present embodiment3/ h, so being run according to this embodiment, it is known that propylene glycol two
The production capacity of acetic acid esters is 144 tons/year of 0.02 × 24 × 300 ≈ (assuming that density is 1g/ml), and tar emission amount is 250-144=
106 tons/year.The product content of major product is 99.71%, and the product content of gained byproduct propylene-glycol diacetate is 96%.
Specific embodiment 3：
1) it as shown in Fig. 2, enters and subtracts by flowmeter by the de- thick finished product of propylene glycol methyl ether acetate gently handled
Press the middle part of rectifying column 2, rectifying tower system depressurized by vacuum pump, the thick finished product liquid part of propylene glycol methyl ether acetate into
Enter by entering vacuum rectification tower 2 after steam heating vaporization in reboiler 1, top gaseous phase is then condensed by overhead condenser 4, is condensed
Liquid then enters in return tank 5, and reflux operation is carried out by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, control tower top pressure is 1 less than 5Kpa (absolute pressure), control reflux ratio:1~1:0.5, control tower bottoms phase temperature is 165
~170 DEG C.
2) in 1) rectifying column indices meet after normal range value, finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is more than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened, is adopted by/h at this time
Go out after heavy constituent propylene-glycol diacetate to carry out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 press filtration of filter pressing pump again
Finished product propylene-glycol diacetate is obtained by filtration into filter device 10；Control side take-off flow is 0.03m herein3/h.Offside
Line produces component sampling analysis, and the content by propylene-glycol diacetate known to chromatography is 95% or more, is contained in this ingredient
Propylene glycol methyl ether acetate is within 1%, and color number is No. 50.
3) after about running 24 hours, the analysis result of finished product is analyzed, finished product content is 99.8% or more, illustrates this process
Positive effect (product content 99.7% in comparative example 2) is played to the purity raising of finished product.
4) 8 interior extraction heavy constituent of kettle to be decolourized accounts for about kettle internal volume is advisable for 60~70%, proceeds by decoloration and press filtration
Operation.
5) after activated carbon being added in decoloration kettle 8, stirring is opened, is about stirred 30~60 minutes, guarantee activated carbon is in a liquid
It suspends uniform, is then turned on filter pressing pump, press filtration is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
Being less than 10 to product color number is advisable.To press filtration product carry out content analysis, it is known that the content of propylene-glycol diacetate be 90% with
Upper (containing 5% propylene glycol methyl ether acetate).
6) it is 0.03m by side take-off in this present embodiment3/ h, so being run according to this embodiment, it is known that propylene glycol two
The production capacity of acetic acid esters is 216 tons/year of 0.03 × 24 × 300 ≈ (assuming that density is 1g/ml), and tar actual emission is more than 50
Ton/year.The product content of major product is 99.8%, and the product content of gained byproduct propylene-glycol diacetate is 95%.
Specific embodiment 4：
1) it as shown in Fig. 2, enters and subtracts by flowmeter by the de- thick finished product of propylene glycol methyl ether acetate gently handled
Press the middle part of rectifying column 2, rectifying tower system depressurized by vacuum pump, the thick finished product liquid part of propylene glycol methyl ether acetate into
Enter by entering vacuum rectification tower 2 after steam heating vaporization in reboiler 1, top gaseous phase is then condensed by overhead condenser 4, is condensed
Liquid then enters in return tank 5, and reflux operation is carried out by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, control tower top pressure is 1 less than 5Kpa (absolute pressure), control reflux ratio:1~1:0.5, control tower bottoms phase temperature is 165
~170 DEG C；
2) in 1) rectifying column indices meet after normal range value, finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is more than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened, is adopted by/h at this time
Go out after heavy constituent propylene-glycol diacetate to carry out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 press filtration of filter pressing pump again
Finished product propylene-glycol diacetate is obtained by filtration into filter device 10；Control side take-off flow is 0.04m3/h.Side line is adopted
Go out component sampling analysis, the content by propylene-glycol diacetate known to chromatography is 90% or more, and color number is No. 50；
3) after about running 24 hours, the analysis result of finished product is analyzed, finished product content 99.8%, illustrate this process at
The purity raising of product does not continue to have effect (finished product content 99.8% in comparative example 3)；
4) the interior extraction heavy constituent of kettle to be decolourized accounts for about kettle internal volume is advisable for 60~70%, proceeds by decoloration and press filtration behaviour
Make；
5) after activated carbon being added in decoloration kettle, stirring is opened, is about stirred 30~60 minutes, guarantee activated carbon hangs in a liquid
It is floating uniform, it is then turned on filter pressing pump, press filtration is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
Product color number is less than 10 and is advisable.Content analysis is carried out to press filtration product, it is known that the content of propylene-glycol diacetate is 70% or more
(being 25% or more containing propylene glycol methyl ether acetate)；
6) it is 0.04m by side take-off in this present embodiment3/ h, so being run according to this embodiment, it is known that propylene glycol two
The production capacity of acetic acid esters is 288 tons/year of 0.04 × 24 × 300 ≈ (assuming that density is 1g/ml), and actual tar emission amount is more than 50
Ton/year.The product content of major product is 99.8% or more, and the product content of gained byproduct propylene-glycol diacetate is 96%.
It is compared by above example, especially compares embodiment 1 and subsequent embodiment, it is known that, it is adopted when using side line
When going out heavy constituent operation, there is good positive interaction to the content raising of major product propylene glycol methyl ether acetate, without side take-off
When, finished product content can only accomplish 99.5%, when side take-off, can accomplish 99.8% or more.Comparing embodiment 2, embodiment
3, embodiment 4 and embodiment 5 are it is found that as side take-off amount is from 0.01m3/ h, steps up 0.04m3When/h, major product
Purity is stepping up, but the content of propylene-glycol diacetate is gradually reducing in the product of side take-off, gradually from 96%
It is reduced to 70%, and influences gradually reducing on reducing heavy constituent discharge, after side take-off reaches a certain amount of, compares propylene glycol
The heavier heavy constituent discharge of diacetate esters will not be reduced, so heavy constituent emission limit can only drop to 50 tons/year.
Preferred embodiment 3 and embodiment 4 are it is found that when side take-off is controlled in 0.02m3/ h~0.03m3When/h, major product is pure
Degree can be controlled 99.7%~99.8%, and the byproduct content of propylene-glycol diacetate can be controlled 95~96%, again
Finally discharge can be preferably minimized component, i.e., 50~106 tons/year.Integrated comparative, present apparatus side take-off 0.025m3/ h or so
To be optimal, determined according to the yield of major product in actual mechanical process.
The advantages of this programme is：
1) added value of propylene glycol methyl ether acetate is increased：Former propylene glycol methyl ether acetate is mainly utilized in this programme
Process units is transformed, and does not carry out new chemical reaction process, you can obtains a kind of new chemical products propylene glycol oxalic acid
Ester, and by market analysis it is found that the price of propylene-glycol diacetate is than major product propylene glycol methyl ether acetate price higher, this
The invisible added value for increasing major product；
2) reduce three-protection design input：By taking present apparatus production capacity as an example, it is assumed that the production capacity of device is 50,000 tons/year, weight
The quality accounting of component is 0.5%, then original weight component treating capacity is 50,000 tons × 0.5%=250 tons/year), due to propylene glycol two
Acetic acid esters account for heavy constituent mass fraction be 80%, then after improvement, heavy constituent discharge capacity be about 250 × (1-80%)=
50 tons/year；
3) product quality of major product is improved：Due to by after this technological transformation, relative to product propylene glycol monomethyl ether second
The higher ingredient propylene-glycol diacetate of acid esters boiling point, as heavy constituent in distillation process constantly from tower by side take-off,
This invisible enrichment process (being that interval produces originally) for reducing heavy constituent in rectifying column, reduces contain propylene glycol in finished product in this way
The content of the possibility of diacetate esters, final products is increased to 99.8% or more from original 99.5%.
4) due to not only containing propylene-glycol diacetate in tower bottoms, also contain many other boiling points than propylene glycol oxalic acid
The high polymer of ester, with continuously running for rectifying, heavy constituent accumulation is more and more, and heavy constituent needs intermittent discharge just to can guarantee
The normal operation of system.In past technical process, since the content of propylene-glycol diacetate accounts for the 80% of heavy constituent content, so
Cause the total amount of heavy constituent relatively more, in the actual production process, heavy constituent emission frequency is once three days (2.4 ton/time).When
After this programme, since 80% propylene-glycol diacetate in heavy constituent continuously produces system as product, so reducing
The discharge of heavy constituent, when technique productions after optimization, heavy constituent emission frequency is that half a month is primary (2.4 ton/time).
Above disclosed is only a kind of preferred embodiment of the present invention, cannot limit the present invention's with this certainly
Interest field, therefore equivalent changes made in accordance with the claims of the present invention, are still within the scope of the present invention.
Claims (10)
1. a kind of process units of propylene-glycol diacetate, including reboiler (1), vacuum rectification tower (2), overhead condenser (4),
Return tank (5) and reflux pump (6), the vacuum rectification tower (2) are equipped with material inlet, the bottom of the vacuum rectification tower (2)
It is connected to the bottom of the reboiler (1), the top of the reboiler (1) is connected to the vacuum rectification tower (2), the decompression
The tower top of rectifying column (2) is connected to overhead condenser (4), and discharge port and the return tank (5) of the overhead condenser (4) connect
Logical, the input terminal of the reflux pump (6) is connected to the return tank (5), output end and the decompression essence of the reflux pump (6)
Evaporate the top connection of tower (2)；It is characterized in that, the process units further includes side take-off cooler (7), decoloration kettle (8), pressure
Filter pump (9) and filter plant (10), the middle part of the input terminal and the vacuum rectification tower (2) of the side take-off cooler (7)
Connection, the output end of the side take-off cooler (7) are connected to the decoloration kettle (8), the bottom of the decoloration kettle (8) and institute
Filter pressing pump (9) connection is stated, the outlet of the filter pressing pump (9) is connected to the filter plant (10).
2. a kind of process units of propylene-glycol diacetate according to claim 1, which is characterized in that the side take-off
Side take-off flowmeter (11) is equipped between cooler (7) and the decoloration kettle (8).
3. a kind of process units of propylene-glycol diacetate according to claim 1, which is characterized in that the rectification under vacuum
The bottom of tower (2) is connected with heavy constituent collecting tank (3).
4. a kind of process units of propylene-glycol diacetate according to claim 1, which is characterized in that the reflux pump
(6) also in parallel on the pipeline being connected to vacuum rectification tower (2) to be equipped with propylene glycol methyl ether acetate discharge line (12), described the third two
Alcohol methyl ether acetate discharge line (12) is equipped with finished product extraction flowmeter (13).
5. a kind of process units of propylene-glycol diacetate according to claim 1, which is characterized in that the filter plant
(10) it is connected to by return duct with the top of decoloration kettle (8), the bottom of the filter plant (10) is equipped with propylene-glycol diacetate
Discharge line (14).
6. a kind of process units of propylene-glycol diacetate according to claim 3, which is characterized in that the heavy constituent is received
The bottom for collecting tank (3) is equipped with heavy constituent discharge pipe (15).
7. a kind of production method of propylene-glycol diacetate, which is characterized in that described in any one of claim 1-6
The process units of propylene-glycol diacetate, is as follows：
S1, by by the de- propylene glycol methyl ether acetate crude product gently handled from the middle part of vacuum rectification tower enter vacuum rectification tower into
Row rectification under vacuum, propylene glycol methyl ether acetate crude product are heated by reboiler by steam, and the gas phase in vacuum rectification tower enters tower
Top, top gaseous phase are condensed into condensate liquid by condenser, and condensate liquid enters in return tank, is flowed back by reflux pump, follows repeatedly
Ring；
S2, extraction progress chromatography, when finished product content is more than 99.5%, control are sampled to propylene glycol methyl ether acetate finished product
Finished product produces；Start side take-off cooler, the heavy constituent generated in vacuum rectification tower is entered into side take-off cooler；
S3, heavy constituent after cooling is entered into decoloration kettle, is added when heavy constituent accounts for the 60%-70% of kettle internal volume in the kettle that decolourizes
Activated carbon is stirred decoloration；
S4, the destainer after decoloration is entered to filter pressing pump progress press filtration；
S5, it the heavy constituent after press filtration is entered into filter device is filtered, constantly recycle, until obtaining content > 95%, color number
Propylene-glycol diacetate less than 10.
8. a kind of production method of propylene-glycol diacetate according to claim 7, which is characterized in that tower top in the S1
Pressure is less than 5Kpa, reflux ratio 1：1~1:0.5, the tower reactor liquidus temperature of vacuum rectification tower is 165~170 DEG C.
9. a kind of production method of propylene-glycol diacetate according to claim 7, which is characterized in that active in the S3
The mass ratio that charcoal accounts for heavy constituent in decoloration kettle is 1%~3%, and mixing time is 0.5~1h.
10. a kind of production method of propylene-glycol diacetate according to claim 7, which is characterized in that the method is also
Including when tower liquid level is up to 80% in vacuum rectification tower, the heavy constituent in tower is discharged into heavy constituent collecting tank.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109206315A (en) * | 2018-08-31 | 2019-01-15 | 江苏华伦化工有限公司 | The method of separating propylene glycol acetate from propylene glycol methyl ether acetate heavy constituent |
| CN110668926A (en) * | 2019-11-25 | 2020-01-10 | 南通百川新材料有限公司 | Propylene glycol methyl ether rectification purification system and method thereof |
| CN112546658A (en) * | 2020-11-13 | 2021-03-26 | 南通百川新材料有限公司 | Novel 2-methoxy-1-propanol acetate de-esterification rectification purification method |
| CN117486721A (en) * | 2023-09-06 | 2024-02-02 | 武汉椿岭科技有限公司 | Decoloring technology of diethylene glycol bis (allyl carbonate) and oligomer optical resin thereof |
-
2018
- 2018-08-15 CN CN201810928275.XA patent/CN108774132A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109206315A (en) * | 2018-08-31 | 2019-01-15 | 江苏华伦化工有限公司 | The method of separating propylene glycol acetate from propylene glycol methyl ether acetate heavy constituent |
| CN110668926A (en) * | 2019-11-25 | 2020-01-10 | 南通百川新材料有限公司 | Propylene glycol methyl ether rectification purification system and method thereof |
| CN112546658A (en) * | 2020-11-13 | 2021-03-26 | 南通百川新材料有限公司 | Novel 2-methoxy-1-propanol acetate de-esterification rectification purification method |
| CN117486721A (en) * | 2023-09-06 | 2024-02-02 | 武汉椿岭科技有限公司 | Decoloring technology of diethylene glycol bis (allyl carbonate) and oligomer optical resin thereof |
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Application publication date: 20181109 |