CN221309568U - Purification system in propylene glycol production - Google Patents
Purification system in propylene glycol production Download PDFInfo
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- CN221309568U CN221309568U CN202322879349.4U CN202322879349U CN221309568U CN 221309568 U CN221309568 U CN 221309568U CN 202322879349 U CN202322879349 U CN 202322879349U CN 221309568 U CN221309568 U CN 221309568U
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- tank
- tower
- extraction
- propylene glycol
- rectifying tower
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- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 title claims abstract description 204
- 238000000746 purification Methods 0.000 title claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 10
- 238000000605 extraction Methods 0.000 claims abstract description 65
- 239000007788 liquid Substances 0.000 claims abstract description 41
- 230000007704 transition Effects 0.000 claims abstract description 34
- 239000002994 raw material Substances 0.000 claims abstract description 27
- 238000011084 recovery Methods 0.000 claims abstract description 14
- 238000010992 reflux Methods 0.000 claims description 20
- 238000004891 communication Methods 0.000 claims description 3
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 abstract description 28
- 230000000694 effects Effects 0.000 abstract description 2
- 238000000926 separation method Methods 0.000 abstract 1
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 57
- 239000000463 material Substances 0.000 description 13
- 239000000047 product Substances 0.000 description 11
- 238000009835 boiling Methods 0.000 description 6
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000004821 distillation Methods 0.000 description 5
- 238000007599 discharging Methods 0.000 description 4
- 239000000284 extract Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 229940079593 drug Drugs 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 241000208125 Nicotiana Species 0.000 description 1
- 235000002637 Nicotiana tabacum Nutrition 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000000998 batch distillation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002537 cosmetic Substances 0.000 description 1
- 239000012043 crude product Substances 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 235000013355 food flavoring agent Nutrition 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 239000010687 lubricating oil Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000575 pesticide Substances 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000002990 reinforced plastic Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 238000005809 transesterification reaction Methods 0.000 description 1
- 229920006337 unsaturated polyester resin Polymers 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Abstract
The utility model discloses a purification system in propylene glycol production, which comprises: the raw material buffer tank is connected with the first feed inlet of the rectifying tower; the side line extraction outlet of the rectifying tower is communicated with the raw material inlet of the extraction tower; the discharge port of the extraction tower is communicated with the product tank, the bottom of the extraction tower is provided with an extraction liquid inlet and an extraction liquid outlet, and the extraction liquid outlet is communicated with the recovery tank; the gas discharge port of the rectifying tower is also connected with a transition fraction tank, and the discharge port of the transition fraction tank is communicated with the first feed port of the rectifying tower. The purification device is provided with the rectifying tower and the extracting tower, crude propylene glycol is extracted from the middle side line of the rectifying tower, the separation effect is improved, and the purity of propylene glycol in the product can be further improved by arranging the transition fraction tank; the propylene carbonate in the product can be extracted by the arrangement of the extraction tower, and propylene carbonate can be recycled while propylene glycol is purified.
Description
Technical Field
The utility model relates to the field of propylene glycol purification, in particular to a purification system in propylene glycol production.
Background
The dimethyl carbonate has good chemical reactivity and can be widely applied to the fields of medicines, pesticides, synthetic materials, dyes, lubricating oil additives, food flavoring agents, electronic chemicals and the like.
Propylene glycol is mainly used in the industries of foods, medicines, tobacco, cosmetics and the like, and has the greatest application as an intermediate for producing surface coating and reinforced plastics in the production of unsaturated polyester resins
In the process for producing dimethyl carbonate and propylene glycol by using a transesterification method, methanol and propylene carbonate are used as raw materials, and the intermittent rectification method is adopted to prepare the dimethyl carbonate and the propylene glycol. Wherein, the bottom of the rectifying tower is used for extracting crude propylene glycol, and the top of the rectifying tower is used for extracting crude dimethyl carbonate. Because the reaction of propylene carbonate and methanol is reversible, and the boiling points of propylene carbonate and propylene glycol are similar, propylene carbonate impurities still exist in the propylene glycol product obtained by the process flow, and the purity of the product is affected. There is a need for a propylene glycol purification unit that removes propylene carbonate and methanol from the product.
Disclosure of utility model
In view of the above-mentioned shortcomings of the prior art, it is an object of the present utility model to provide a purification system in the production of propylene glycol. The system can effectively separate the methanol and the propylene carbonate in the propylene glycol crude product through the transition fraction tank and the extraction tower which are arranged in the rectifying tower.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a purification system in co-production of propylene glycol from dimethyl carbonate, comprising:
The raw material buffer tank is connected with the first feed inlet of the rectifying tower; the side line extraction outlet of the rectifying tower is communicated with the raw material inlet of the extraction tower; the discharge port of the extraction tower is communicated with the product tank, the bottom of the extraction tower is provided with an extraction liquid inlet and an extraction liquid outlet, and the extraction liquid outlet is communicated with the recovery tank; the gas discharge port of the rectifying tower is also connected with a transition fraction tank, and the discharge port of the transition fraction tank is communicated with the first feed port of the rectifying tower.
When the propylene carbonate recovery device is used, raw materials enter a rectifying tower from a raw material buffer tank to carry out rectification, the boiling point of methanol is lower than that of propylene glycol, so that the methanol is gasified firstly, propylene glycol is extracted from a side extraction port of the rectifying tower, and propylene carbonate is similar to the boiling point of propylene glycol, so that part of propylene carbonate is mixed in the propylene glycol extracted from the side extraction port, and propylene carbonate in the propylene glycol is required to be removed; specifically, propylene glycol is extracted from a side-line extraction port and enters an extraction tower for extraction, propylene carbonate is dissolved in an extraction liquid and enters a recovery tank, the propylene glycol is insoluble in the extraction liquid and relatively layered with the extraction liquid, and finally the propylene glycol enters a product tank, and propylene carbonate in the propylene glycol is removed through extraction, so that the propylene glycol is purified.
In the process of rectification, a part of propylene glycol is evaporated into gas, so that the gas entering the top of the rectification tower contains methanol and propylene glycol, the part of gas enters a transition fraction tank through a gas discharge port at the top of the tower top, the gas is cooled into liquid in the transition fraction tank, and the methanol and the propylene glycol in a liquid state enter the rectification tower through a discharge port of the transition fraction tank and a first feed port of the rectification tower, so that the propylene glycol evaporated in a gas form is changed into liquid, and enters the rectification tower again, thereby realizing the recovery of the part of propylene glycol.
Preferably, a feeding pump is arranged on a feeding pipe between the raw material buffer tank and the rectifying tower, and a discharging hole of the transition fraction tank is communicated with the feeding pipe.
Through the setting of charge pump, the raw materials in the raw materials buffer tank of being convenient for send into the rectifying column.
Preferably, a material transferring pump is arranged between the side line extraction outlet and the extraction tower raw material inlet, and a condenser is further arranged at the pump inlet of the material transferring pump.
Through the setting of change material pump, be convenient for send into the extraction column with the side line of rectifying column liquid of taking out, the effect of condenser then is the temperature of reducing the side line liquid of taking out, provides suitable temperature condition for the extraction.
Preferably, a reflux tank is further connected between the liquid discharge port of the rectifying tower and the transition fraction tank, and a tower top condenser is further connected between the reflux tank and the liquid discharge port.
Through the arrangement of the condenser at the top of the tower, the gaseous light component is conveniently and rapidly cooled into liquid, the subsequent reflux operation is convenient, and the reflux tank is used for temporarily storing the liquid light component and sending the liquid light component into the light component tank or the transition fraction tank according to the concentration of the light component methanol in the reflux tank.
Preferably, the reflux tank is also communicated with a light component tank, and the light component tank is arranged in parallel with the transition fraction tank.
When batch rectification starts, because the whole temperature inside the rectifying tower is low, the gas entering the reflux tank does not contain propylene glycol, and the reflux tank is communicated with the light component tank at the moment, so that methanol can be conveniently collected and recycled; after batch distillation for a period of time, the temperature in the distillation column rises, part of propylene glycol enters the reflux tank along with methanol, at the moment, the reflux tank is communicated with the transition fraction tank, materials in the transition fraction tank and the raw material for the next distillation are sent into the distillation column, and the yield of propylene glycol is improved, and meanwhile, the extraction purity of propylene glycol for the next distillation can also be improved.
Preferably, a liquid discharge port at the bottom of the rectifying tower is sequentially communicated with a circulating pump, a tower bottom reboiler and a reboiling inlet of the rectifying tower.
Through the arrangement of the circulating pump and the tower bottom reboiler, the components of propylene glycol and propylene carbonate at the tower bottom are heated to be gas, and the gas returns to the middle section of the rectifying tower for repeated rectification, so that the recovery efficiency of propylene glycol is improved.
Preferably, the bottom reboiler is also connected to a condensate tank.
Through the setting of condensate pot, be favorable to storing and stabilizing the lime set that reboiler produced, avoid the too high or too low condition of pressure in the reboiler to maintain the normal operating of reboiler.
The utility model has the beneficial effects that:
(1) When the propylene carbonate recovery device is used, raw materials enter a rectifying tower from a raw material buffer tank to carry out rectification, the boiling point of methanol is lower than that of propylene glycol, so that the methanol is gasified firstly, propylene glycol is extracted from a side extraction port of the rectifying tower, and propylene carbonate is similar to the boiling point of propylene glycol, so that part of propylene carbonate is mixed in the propylene glycol extracted from the side extraction port, and propylene carbonate in the propylene glycol is required to be removed; specifically, propylene glycol is extracted from a side-line extraction port and enters an extraction tower for extraction, propylene carbonate is dissolved in an extraction liquid and enters a recovery tank, the propylene glycol is insoluble in the extraction liquid and relatively layered with the extraction liquid, and finally the propylene glycol enters a product tank, and propylene carbonate in the propylene glycol is removed through extraction, so that the propylene glycol is purified.
(2) In the process of rectification, a part of propylene glycol is evaporated into gas, so that the gas entering the top of the rectification tower contains methanol and propylene glycol, the part of gas enters a transition fraction tank through a gas discharge port at the top of the tower top, the gas is cooled into liquid in the transition fraction tank, and the methanol and the propylene glycol in a liquid state enter the rectification tower through a discharge port of the transition fraction tank and a first feed port of the rectification tower, so that the propylene glycol evaporated in a gas form is changed into liquid, and enters the rectification tower again, thereby realizing the recovery of the part of propylene glycol.
Drawings
Fig. 1 is a schematic structural view of the present utility model.
Wherein, 1-raw material buffer tank, 2-rectifying tower, 3-side draw-out port, 4-extraction tower, 5-product tank, 6-extract inlet, 7-recovery tank, 8-feed pump, 9-transfer pump, 10-condenser, 11-overhead condenser, 12-reflux tank, 13-transition fraction tank, 14-circulation pump, 15-tower bottom reboiler, 16-condensate tank and 17-light component tank.
Detailed Description
It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.
In order to enable those skilled in the art to more clearly understand the technical scheme of the present application, the technical scheme of the present application will be described in detail with reference to specific embodiments.
As shown in fig. 1, this embodiment provides a purification system in co-producing propylene glycol from dimethyl carbonate, which includes:
The raw material buffer tank 1 is connected with a first feed inlet of the rectifying tower 2; the side line extraction outlet 3 of the rectifying tower 2 is communicated with the raw material inlet of the extraction tower 4; the discharge port of the extraction tower 4 is communicated with a product tank 5, the bottom of the extraction tower 4 is provided with an extraction liquid inlet 6 and an extraction liquid outlet, and the extraction liquid outlet is communicated with a recovery tank 7; the top of the rectifying tower 2 is also connected with a transition fraction tank 13, and a discharge port of the transition fraction tank 13 is communicated with a first feed port of the rectifying tower 2.
Preferably, a feeding pump 8 is arranged on a feeding pipe between the raw material buffer tank 1 and the rectifying tower 2, and a discharging hole of the transition fraction tank is communicated with the feeding pipe. Preferably, a material transferring pump 9 is arranged between the side line extraction outlet 3 and the raw material inlet of the extraction tower 4, and a condenser 10 is also arranged at the pump inlet of the material transferring pump 9. Preferably, a reflux tank 12 is further connected between the liquid discharge port of the rectifying tower 2 and the transition fraction tank 13, and an overhead condenser 11 is further connected between the reflux tank 12 and the liquid discharge port. Preferably, the reflux drum 12 is also in communication with a lights drum 17, the lights drum 17 being disposed in parallel with the transition cut drum 13. Preferably, the liquid outlet at the bottom of the rectifying tower is sequentially communicated with the circulating pump 14, the tower bottom reboiler 15 and the reboiling inlet of the rectifying tower 2. Preferably, the bottom reboiler 15 is also connected to a condensate tank 16.
Materials consisting of propylene glycol, propylene carbonate and methanol enter a rectifying tower from a raw material buffer tank, the methanol and part of the propylene glycol in the rectifying tower are evaporated into gas, the gas enters a transition fraction tank through the tower top, and the gas is cooled in the transition fraction tank, so that the propylene glycol is sent into the rectifying tower again; propylene glycol with higher purity can be extracted from a side extraction port of the rectifying tower, and at the moment, because the boiling point of propylene carbonate is similar to that of propylene glycol, part of propylene carbonate is mixed in the propylene glycol, so that the side extraction port is required to be connected with the extracting tower, and propylene carbonate is removed; propylene glycol enters the extraction tower, propylene carbonate enters the recovery tank after extraction, and propylene glycol enters the product tank.
The operation flow of the utility model is as follows:
Propylene glycol, propylene carbonate and methanol in the raw material buffer tank enter a rectifying tower through a first feed inlet, the rectifying tower is heated and rectified, the mixture of the methanol and the propylene glycol is evaporated into gas and enters the tower top,
(1) The system was evacuated.
(2) And when the negative pressure of the rectifying tower is about-80 KPa, returning the transition fraction in the transition fraction tank to the rectifying tower.
(4) And (3) conveying the materials in the raw material buffer tank into the rectifying tower by using a feed pump until the liquid level reaches 3600-3800mm.
(5) And simultaneously, in connection with dispatching, a steam heating valve of 1.0MPa is slowly opened in advance at the bottom of the rectifying tower to heat the tower kettle, and the steam heating regulating valve is controlled at 40%.
(6) And (3) performing total reflux on the rectifying tower, discharging the material from the reflux tank to the transition fraction tank when the temperature point of the rectifying tower is not changed greatly, discharging the material after 5min, changing the material to the light component tank 17, and collecting light liquid.
(7) When the temperature of the top of the rectifying tower is raised to 75 ℃, top production is changed into a transition fraction tank.
(8) The temperature of the top of the tower is more than 108 ℃, and after the reflux quantity is relatively stable, the side line of the transfer pump is started to be extracted to the extraction tower.
(9) The side-line extracted material enters the extraction tower from the top raw material inlet, the extractant enters the extraction tower from the bottom extract inlet, the extractant extracts propylene carbonate in the material, then enters the recovery tank from the bottom extract outlet, and the raffinate, namely propylene glycol, enters the product tank from the product discharge port of the extraction tower. Sampling and analyzing to obtain PG with content of above 99.6%, water content of below 0.15%, chromaticity below 10, and delivering to tank area V2803 at high liquid level.
(11) Repeating the above operation steps to carry out the next distillation operation.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (7)
1. A purification system in propylene glycol production, comprising:
A raw material buffer tank (1) which is connected with a first feed inlet of the rectifying tower (2); the side line extraction outlet (3) of the rectifying tower is communicated with the raw material inlet of the extraction tower (4); the discharge port of the extraction tower is communicated with a product tank (5), the bottom of the extraction tower is provided with an extraction liquid inlet (6) and an extraction liquid outlet, and the extraction liquid outlet is communicated with a recovery tank (7); the gas discharge port of the rectifying tower is also connected with a transition fraction tank (13), and the discharge port of the transition fraction tank is communicated with the first feed port of the rectifying tower.
2. Purification system according to claim 1, characterized in that a feed pump (8) is arranged on the feed pipe between the raw material buffer tank and the rectifying column, and the discharge port of the transition fraction tank is connected with the feed pipe.
3. Purification system in propylene glycol production according to claim 2, characterized in that a transfer pump (9) is arranged between the side offtake and the extraction column raw material inlet, the pump inlet of the transfer pump being further provided with a condenser (10).
4. Purification system according to claim 1, characterized in that a reflux drum (12) is also connected between the liquid outlet of the rectifying column and the transition cut drum, and an overhead condenser (11) is also connected between the reflux drum and the liquid outlet.
5. Purification system according to claim 4, characterized in that the reflux drum is also in communication with a light fraction drum (17) which is arranged in parallel with the transition fraction drum.
6. The purification system of claim 1, wherein the liquid outlet at the bottom of the rectifying column is in communication with a circulation pump (14), a bottom reboiler (15) and a reboiling inlet of the rectifying column in sequence.
7. The purification system of claim 6, wherein the bottoms reboiler is further coupled to a condensate tank (16).
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN221309568U true CN221309568U (en) | 2024-07-12 |
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