CN208717201U - A kind of process units of propylene-glycol diacetate - Google Patents
A kind of process units of propylene-glycol diacetate Download PDFInfo
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- CN208717201U CN208717201U CN201821313933.6U CN201821313933U CN208717201U CN 208717201 U CN208717201 U CN 208717201U CN 201821313933 U CN201821313933 U CN 201821313933U CN 208717201 U CN208717201 U CN 208717201U
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- glycol diacetate
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Abstract
The utility model relates to technical field of fine chemical production, specifically disclose a kind of process units 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 utility model 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, qualified propylene-glycol diacetate is obtained by 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
The utility model belongs to technical field of fine chemical production, specifically a kind of raw using propylene glycol methyl ether acetate
Produce the process units of device by-product propylene-glycol diacetate.
Background technique
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, suitable for high-grade paint, the solvent of the various polymer of ink, including it is 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 coating, solvent best in 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 HG/T3940-2007 standard requirements.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, it is subsequent, 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- reboiler, 2- finished product decompression essence
Evaporate tower, 3- heavy constituent collecting tank, 4- overhead condenser, 5- return tank, 6- reflux pump.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 that 1:1~1:0.5 is advisable, and it is qualified to sample to finished product,
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
It in tank 3, after tower bottoms is cooling, is packed, waste liquid furnace 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 requirements of HG/T3940-2007, i.e. final product quality content is greater 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 of product impurity can be reduced, to achieve the purpose that improve product purity.Additionally, due to matter of the heavy constituent in finished product
Measuring accounting is 0.5%, 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.
Utility model content
Propylene glycol methyl ether acetate process units by-product propylene glycol diethyl is utilized the purpose of the utility model is to provide a kind of
The device of acid esters handles the heavy constituent generated in propylene glycol methyl ether acetate distillation process, so that it is higher to obtain purity
Propylene-glycol diacetate, effectively handled the heavy constituent tar in propylene glycol methyl ether acetate production process, reduced useless
The generation of liquid simultaneously reduces processing cost.
In order to solve the above technical problems, the utility model provides a kind of process units of propylene-glycol diacetate, including
Reboiler, vacuum rectification tower, overhead condenser, return tank and reflux pump, the vacuum rectification tower is equipped with material inlet, described
The bottom of vacuum rectification tower is connected to the bottom of the reboiler, and the top of the reboiler is connected to the vacuum rectification tower,
The tower top of the vacuum rectification tower is connected to overhead condenser, and the discharge port of the overhead condenser is connected to the return tank,
The input terminal of the reflux pump is connected to the return tank, is connected at the top of the output end of the reflux pump and the vacuum rectification tower
It is logical；The process units further includes that side take-off cooler, decoloration kettle, filter pressing pump and filter plant, the side take-off are cooling
The input terminal of device is connected to the middle part of the vacuum rectification tower, and the output end of the side take-off cooler and the decoloration kettle connect
Logical, 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 pipe, 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 beneficial effects of the utility model are: the utility model increases side line in propylene glycol methyl ether acetate production system
Cooler is produced, it, will be relative to propylene glycol methyl ether acetate boiling point in the case where not influencing propylene glycol methyl ether acetate production
Higher ingredient propylene-glycol diacetate as heavy constituent during rectification under vacuum by side take-off, closed by reaction
The waste liquid generated in propylene glycol methyl ether acetate production process is reasonably utilized in the propylene-glycol diacetate of lattice, reduces weight
The discharge of component, while also improving the content of propylene glycol methyl ether acetate product.
Detailed description of the invention
It, below will be to institute in embodiment or description of the prior art in order to illustrate more clearly of the technical solution of the utility model
Attached drawing to be used is needed to be briefly described, it should be apparent that, the accompanying drawings in the following description is only some of the utility model
Embodiment for those of ordinary skill in the art without creative efforts, can also be attached according to these
Figure obtains other attached drawings.
Fig. 1 is the process units structure chart of propylene glycol methyl ether acetate traditional in background technique；
Fig. 2 is the process units structure chart of the utility model propylene-glycol diacetate.
In figure: 1- reboiler, 2- vacuum rectification tower, 3- heavy constituent collecting tank, 4- overhead condenser, 5- return tank, 6- are returned
Stream pump, 7- side take-off cooler, 8- decolourize kettle, 9- filter pressing pump, 10- filter plant, 11- side take-off flowmeter, 12- the third two
Alcohol methyl ether acetate discharge line, 13- finished product produce flowmeter, 14- propylene-glycol diacetate discharge line, 15- heavy constituent row
Outlet pipe.
Specific embodiment
Below in conjunction with the utility model Figure of description, the technical scheme in the embodiment of the utility model is carried out clear
Chu is fully described by, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole realities
Apply example.Based on the embodiments of the present invention, those of ordinary skill in the art are without creative labor
Every other embodiment obtained, fall within the protection scope of the utility model.
The technical solution disclosed in the utility model embodiment is, a kind of propylene-glycol diacetate as shown in Figure 2
Process units, including reboiler 1, vacuum rectification tower 2, overhead condenser 4, return tank 5 and reflux pump 6, the rectification under vacuum
The middle part of tower 2 is equipped with material inlet, and the bottom of the vacuum rectification tower 2 is connected to the bottom of the reboiler 1, the reboiler
1 top is connected to the vacuum rectification tower 2, and the tower top of the vacuum rectification tower 2 is connected to overhead condenser 4, the tower top
The discharge port of condenser 4 is connected to the return tank 5, and the input terminal of the reflux pump 6 is connected to the return tank 5, and described time
The output end of stream pump 6 is connected to the top of the vacuum rectification tower 2, on the pipeline that the reflux pump 6 is connected to vacuum rectification tower 2
Also in parallel to be equipped with propylene glycol methyl ether acetate discharge line 12, the propylene glycol methyl ether acetate discharge line 12 is equipped with finished product
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 furnace 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 aperture at the collection annular groove of tower reactor packing layer suitable position, increases side line
Discharge outlet 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 in this way, reduce the possibility of extraction major product propylene glycol methyl ether acetate
Property, in addition to guarantee 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 decoloration kettle 8, the bottom of the decoloration kettle 8 is connected to the filter pressing pump 9, the filters pressing
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 pipe, institute
The bottom for stating filter plant 10 is equipped with propylene-glycol diacetate discharge line 14.
A kind of course of work of the process units of propylene-glycol diacetate of the utility model is as follows: will be by de- light processing
Propylene glycol methyl ether acetate crude product from the middle part of vacuum rectification tower enter vacuum rectification tower carry out rectification under vacuum, propylene glycol monomethyl ether
Acetic acid esters crude product is heated by reboiler by steam, and the gas phase in vacuum rectification tower enters tower top, and tower top pressure is less than 5Kpa, tower
Top gas is mutually condensed into condensate liquid by condenser, and condensate liquid enters in return tank, is flowed back by reflux pump, reflux ratio 1:1
~1:0.5, tower reactor liquidus temperature are 165~170 DEG C, iterative cycles；
When operating index every in vacuum rectification tower reaches the requirement in S1, propylene glycol methyl ether acetate finished product is sampled
Extraction carries out chromatography, when finished product content is greater than 99.5%, control finished product extraction, by taking 50,000 tons/year of production capacity as an example (with
Similarly hereinafter), then finished product extraction flow is about 7.5m3/h；Start side take-off cooler, the heavy constituent that will be generated in vacuum rectification tower
It in the accounting of finished product is 0.5% according to heavy constituent total amount, i.e. heavy constituent side take-off flow is small into side take-off cooler
In 0.0375m3/ h is advisable；
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
Entering active carbon and is stirred decoloration, the mass ratio that active carbon accounts for heavy constituent in decoloration kettle is 1%~3%, mixing time is 0.5~
1h；Destainer after decoloration is entered into filter pressing pump and carries out filters pressing；Heavy constituent after filters pressing is entered filter device to be filtered, no
Disconnected circulation, until obtaining content > 95%, propylene-glycol diacetate of the color number less than 10；When tower liquid level reaches in vacuum rectification tower
When 80%, the heavy constituent of boiling points other in the tower polymer accumulation higher than propylene-glycol diacetate is discharged 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, carries out reflux operation by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, for control tower top pressure less than 5Kpa (absolute pressure), control reflux ratio is 1:1~1:0.5, and control tower bottoms phase temperature is 165
~170 DEG C；
2) after rectifying column indices meet normal range value in 1), finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is greater than 99.5%, control finished product extraction is 7.5m3/h；
3) after about running 24 hours, the analysis interpretation of result to finished product, 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, and about 3 days
Discharge is primary, and 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 amount is 250 tons/year, and the content of propylene glycol methyl ether acetate is 99.5%.
Specific embodiment of the utility model 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, carries out reflux operation by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, for control tower top pressure less than 5Kpa (absolute pressure), control reflux ratio is 1:1~1:0.5, and control tower bottoms phase temperature is 165
~170 DEG C；
2) after rectifying column indices meet normal range value in 1), finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is greater than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened at this time, is adopted by/h
Carried out after heavy constituent propylene-glycol diacetate out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 filters pressing 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) about run 24 hours after, the analysis interpretation of result to finished product, finished product content 99.5%, illustrate this process at
Positive effect is not played in the purity raising of product；
4) heavy constituent is produced in kettle 8 to be decolourized to account for about the 60~70% of kettle internal volume and be advisable, start to carry out decoloration and filters pressing
Operation；
5) after active carbon being added in decoloration kettle 8, stirring is opened, is about stirred 30~60 minutes, guarantee active carbon is in a liquid
It suspends uniformly, is then turned on filter pressing pump 9, filters pressing is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
It is advisable to product color number less than 10.To filters pressing product carry out content analysis, it is known that the content of propylene-glycol diacetate be 96% with
On.
It 6) 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, carries out reflux operation by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, for control tower top pressure less than 5Kpa (absolute pressure), control reflux ratio is 1:1~1:0.5, and control tower bottoms phase temperature is 165
~170 DEG C；
2) after rectifying column indices meet normal range value in 1), finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is greater than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened at this time, is adopted by/h
Carried out after heavy constituent propylene-glycol diacetate out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 filters pressing 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.Opposite side
Line produces component sampling analysis, and the content by propylene-glycol diacetate known to chromatography is 96% or more, contains in this ingredient
Propylene glycol methyl ether acetate is within 0.1%, and color number is No. 50；
3) about run 24 hours after, the analysis interpretation of result to finished product, finished product content 99.7%, illustrate this process at
The purity of product, which improves, plays positive effect (content of comparison 99.5%).
4) account for about kettle internal volume wait extraction heavy constituent in the kettle that decolourizes is advisable for 60~70%, starts to carry out decoloration and filters pressing behaviour
Make；
5) after active carbon being added in decoloration kettle 8, stirring is opened, about stirring 30~60 minutes, guarantees active carbon in liquid
It is middle to suspend uniformly, it is then turned on filter pressing pump, filters pressing 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 filters pressing product, it is known that the content of propylene-glycol diacetate is 96%
(about contain 1% propylene glycol methyl ether acetate) above；
It 6) 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, carries out reflux operation by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, for control tower top pressure less than 5Kpa (absolute pressure), control reflux ratio is 1:1~1:0.5, and control tower bottoms phase temperature is 165
~170 DEG C.
2) after rectifying column indices meet normal range value in 1), finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is greater than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened at this time, is adopted by/h
Carried out after heavy constituent propylene-glycol diacetate out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 filters pressing 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.Opposite side
Line produces component sampling analysis, and the content by propylene-glycol diacetate known to chromatography is 95% or more, contains 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 interpretation of result to finished product, 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) producing heavy constituent in kettle 8 to be decolourized to account for about kettle internal volume is 60~70% to be advisable, and starts to carry out decoloration and filters pressing
Operation.
5) after active carbon being added in decoloration kettle 8, stirring is opened, is about stirred 30~60 minutes, guarantee active carbon is in a liquid
It suspends uniformly, is then turned on filter pressing pump, filters pressing is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
It is advisable to product color number less than 10.To filters pressing 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).
It 6) 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 greater 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, carries out reflux operation by reflux pump 6；It is matched according to production capacity, present apparatus charging control is 7.5
~8m3, for control tower top pressure less than 5Kpa (absolute pressure), control reflux ratio is 1:1~1:0.5, and control tower bottoms phase temperature is 165
~170 DEG C；
2) after rectifying column indices meet normal range value in 1), finished product extraction is sampled and carries out chromatography point
Analysis, when finished product content is greater than 99.5%, control finished product extraction is 7.5m3Side take-off cooler 7 is opened at this time, is adopted by/h
Carried out after heavy constituent propylene-glycol diacetate out it is cooling after enter decoloration 8 decolorization of kettle, subsequently into after 9 filters pressing 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
Component sampling analysis out, the content by propylene-glycol diacetate known to chromatography are 90% or more, and color number is No. 50；
3) about run 24 hours after, the analysis interpretation of result to finished product, 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) account for about kettle internal volume wait extraction heavy constituent in the kettle that decolourizes is advisable for 60~70%, starts to carry out decoloration and filters pressing behaviour
Make；
5) after active carbon being added in decoloration kettle, stirring is opened, is about stirred 30~60 minutes, guarantee active carbon hangs in a liquid
It is floating to be uniformly then turned on filter pressing pump, filters pressing is carried out to destainer, constantly recycles, with specific reference to 3 sampling analysis of sample point, obtains
Product color number is advisable less than 10.Content analysis is carried out to filters pressing 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)；
It 6) 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 greater 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 embodiments, especially compares embodiment 1 and subsequent embodiment, it is known that, it is adopted when using side line
When heavy constituent operates out, 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 heavy constituent discharge is reduced, 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 control 99.7%~99.8%, and the byproduct content of propylene-glycol diacetate can control 95~96%, again
Component is finally discharged and can be preferably minimized, i.e., and 50~106 tons/year.It is comprehensively compared, present apparatus side take-off 0.025m3/ h or so
To be optimal, determined in actual mechanical process according to the yield of major product.
The advantages of this programme are as follows:
1) it increases the added value of propylene glycol methyl ether acetate: mainly utilizing former propylene glycol methyl ether acetate in this programme
Process units is transformed, and does not carry out new chemical reaction process, and a kind of new chemical products propylene glycol oxalic acid can be obtained
Ester, and pass through market analysis it is found that the price of propylene-glycol diacetate is higher than major product propylene glycol methyl ether acetate price, this
The invisible added value for increasing major product；
2) reduce three-protection design investment: 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 by improvement after, heavy constituent discharge amount be about 250 × (1-80%)=
50 tons/year；
3) product quality of major product is improved: after passing through 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 originally that interval produces) for reducing heavy constituent in rectifying column, reduces in finished product in this way containing propylene glycol
The content of a possibility that diacetate esters, final products are increased to 99.8% or more from original 99.5%.
4) due to not only containing propylene-glycol diacetate in tower bottoms, also containing 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 production 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 utility model, cannot limit this reality certainly with this
With novel interest field, therefore equivalent variations made according to the claim of the utility model, still belong to the utility model and is covered
Range.
Claims (6)
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 the discharge port of the overhead condenser (4) and the return tank (5) are even
Logical, the input terminal of the reflux pump (6) is connected to the return tank (5), the output end of the reflux pump (6) and decompression essence
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 input terminal of the side take-off cooler (7) and the middle part of the vacuum rectification tower (2)
Connection, the output end of the side take-off cooler (7) are connected to the decoloration kettle (8), the bottom of 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) are 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 the top of decoloration kettle (8) by return pipe, 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).
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| CN201821313933.6U CN208717201U (en) | 2018-08-15 | 2018-08-15 | A kind of process units of propylene-glycol diacetate |
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| CN201821313933.6U CN208717201U (en) | 2018-08-15 | 2018-08-15 | A kind of process units of propylene-glycol diacetate |
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