CN214299725U - Purification device for PTA (purified terephthalic acid) refining mother liquor - Google Patents
Purification device for PTA (purified terephthalic acid) refining mother liquor Download PDFInfo
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- CN214299725U CN214299725U CN202120197934.4U CN202120197934U CN214299725U CN 214299725 U CN214299725 U CN 214299725U CN 202120197934 U CN202120197934 U CN 202120197934U CN 214299725 U CN214299725 U CN 214299725U
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Abstract
The utility model relates to a chemical wastewater treatment technical field specifically is a purifier of PTA refined mother liquor, including extraction column, strip tower and rectifying column, the top of the tower of rectifying column passes through the pipeline and links to each other with heat pump compressor, and the tower cauldron of rectifying column passes through the pipeline and links to each other with tower cauldron reboiler, and heat pump compressor is used for heating the gaseous phase that comes from the rectifying column, and tower cauldron reboiler is used for adopting the heated gaseous phase to come from the liquid phase of rectifying column as the heat source heating. The utility model discloses a to methyl benzoic acid's recycle, realize the heat pump rectification through rectifying column, heat pump compressor and tower cauldron reboiler, can obtain high-quality purified water, realize the regeneration and utilization of water resource, have that the flow is short, the energy consumption is low, pollute less, can realize serialization production's characteristics.
Description
Technical Field
The utility model relates to a chemical wastewater treatment technical field specifically is a purifier of PTA refined mother liquor.
Background
The PTA production process mainly comprises an oxidation reaction process and a hydrofining process, wherein in the oxidation process, two methyl groups on a benzene ring are sequentially converted into alcohol, aldehyde and acid through p-xylene liquid-phase air oxidation to obtain solid Crude Terephthalic Acid (CTA), and then p-carboxybenzaldehyde (4-CBA) which is a main impurity in the solid is reduced into p-toluic acid which is easily soluble in water through the hydrofining process to be removed. According to the characteristic that the solubility of the p-toluic acid in water is much higher than that of the phthalic acid in water, the crude terephthalic acid is subjected to impurity removal by hydrogenation, and then is subjected to crystallization, centrifugal separation, drying, dehydration and other processes to produce a refined PTA finished product. Therefore, in the hydrorefining process, a large amount of water is practically required as the water for dissolving terephthalic acid, and a large amount of wastewater is generated after crystallization and centrifugal filtration, and is generally referred to as a refining mother liquor in the industry. P-toluic acid is both a major impurity in these refined mother liquors and an intermediate product of the PX oxidation process. If the p-toluic acid in the refined mother liquor can be recovered, the PTA wastewater can be purified and returned to the hydrofining process to be used as solvent water for recycling, and the p-toluic acid can be recovered to improve the yield of PTA, so that the two purposes are achieved.
In recent years, PX is mainly used as an extractant in the treatment of a purification mother liquor to extract the purification mother liquor. Raw material PX is used as a solvent to extract p-toluic acid in the wastewater, and then the PX and the p-toluic acid are returned to an oxidation reactor together, so that the p-toluic acid can be converted into a product PTA through deep oxidation. On one hand, the method saves the PX regeneration step, reduces the extraction cost, on the other hand, can purify PTA wastewater, returns the PTA wastewater to the hydrofining process to be used as solvent water for recycling, and can also recover the p-toluic acid, thereby achieving three purposes. PX is similar to the structure of p-toluic acid, p-toluic acid is easy to extract from a water phase to a solvent phase, the PX is insoluble in water, trace PX remained in the extracted water can be completely removed through gas stripping, and the PX is recovered after gas cooling, so that the PX is the optimal extractant.
The invention discloses a method for treating PTA refined wastewater by adopting a combination of extraction-ultrafiltration-reverse osmosis, wherein p-xylene is adopted to extract refined wastewater of purified terephthalic acid, an extract phase is returned to a preparation process of purified terephthalic acid, a raffinate phase is subjected to ultrafiltration and reverse osmosis treatment, the permeated water reaches the recycling standard, and concentrated water is returned to an extraction step of p-xylene or to a preparation process of purified terephthalic acid. The invention needs to be used by matching extraction with an ultrafiltration reverse osmosis system, but the ultrafiltration reverse osmosis system has short service life, needs to be replaced frequently and has high process cost.
The invention patent of the publication No. CN102910761B discloses a technology for reducing the COD in PTA wastewater by an extraction method, which firstly uses a solvent to extract a large amount of organic carboxylic acids such as benzoic acid, p-toluic acid, p-carboxybenzyl alcohol, p-carboxybenzaldehyde, terephthalic acid and the like in the wastewater, and then uses a stripping method to remove residual PX, thereby greatly reducing the COD concentration in the wastewater. The invention adopts extraction and stripping methods to reduce COD in the refined mother liquor, but the energy consumption of common stripping is higher.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a purifier of PTA refined mother liquor to solve the problem that proposes among the above-mentioned background art.
In order to achieve the above object, the utility model provides a following technical scheme: a purification device of PTA refining mother liquor comprises
The extraction tower is used for extracting the p-toluic acid in the PTA refining mother liquor through PX;
the stripping tower is used for stripping the PTA refined mother liquor from which the p-methylbenzoic acid is removed and removing PX in the PTA refined mother liquor;
the rectifying tower is used for rectifying the PTA refined mother liquor from which PX is removed and concentrating the PTA refined mother liquor;
the PTA refined mother liquor with PX removed enters the middle part of the rectifying tower, the top of the rectifying tower is connected with a heat pump compressor through a pipeline, a tower kettle of the rectifying tower is connected with a tower kettle reboiler through a pipeline, the heat pump compressor is used for heating a gas phase from the rectifying tower, and the tower kettle reboiler is used for heating a liquid phase from the rectifying tower by using the heated gas phase as a heat source.
Optionally, a backup cooler is included for cooling the gas phase flowing from the kettle reboiler.
Optionally, the mass transfer element in the extraction tower is an anti-clogging filler or an anti-clogging tray, the operating pressure of the extraction tower is 0.2 MPaG-2.0 MPaG, and the operating temperature of the extraction tower is 50-170 ℃; PX and PTA refined mother liquor are in countercurrent contact in the extraction tower.
Optionally, the mass transfer element of the stripping tower is a filler or a tray, the operating pressure of the stripping tower is 0.02 MPaG-0.2 MPaG, and the operating temperature of the stripping tower is 105-120 ℃.
Optionally, the operating pressure of the rectifying tower is-0.04 MPaG to-0.06 MPaG, and the operating temperature of the rectifying tower is 50-90 ℃.
Optionally, the compression ratio of the heat pump compressor is 1.5-2.5.
Compared with the prior art, the utility model provides a purifier of refined mother liquor of PTA possesses following beneficial effect: the utility model discloses a to methyl benzoic acid's recycle, realize the heat pump rectification through rectifying column, heat pump compressor and tower cauldron reboiler, can obtain high-quality purified water, realize the regeneration and utilize of water resource, reduce wastewater discharge by a wide margin, have that the flow is short, the energy consumption is low, pollute less, can realize serialization production's characteristics, have great economic benefits, environmental benefit, social and practical value.
Drawings
Fig. 1 is a schematic view of the overall structure of the present invention.
In the figure: 1. an extraction tower; 2. a stripping column; 3. a rectifying tower; 4. a heat pump compressor; 5. a tower kettle reboiler; 6. a backup cooler.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Example (b): please refer to fig. 1, the utility model provides a purification device of PTA refined mother liquor, including the extraction tower 1 that is arranged in extracting the p-toluic acid in the PTA refined mother liquor through PX, the stripper 2 that is arranged in stripping the PTA refined mother liquor that has got rid of p-toluic acid, the rectifying column 3 that is used for rectifying the PTA refined mother liquor that has got rid of PX, the heat pump compressor 4 that links to each other through the pipeline with the top of the rectifying column 3, the tower cauldron reboiler that links to each other through the pipeline with the tower cauldron of rectifying column 3, and the backup cooler 6 that is used for cooling the gaseous phase that follows tower cauldron reboiler 5 and takes. Wherein, the heat pump compressor 4 is used for heating the gaseous phase that comes from the rectifying column 3, and the cauldron reboiler 5 is used for adopting the gaseous phase that has heated as the heat source heating to come from the liquid phase of rectifying column 3, and the gaseous phase of following cauldron reboiler 5 after the condensation of reserve cooler 6, partly as the backward flow, flows back into rectifying column 3, and partly as the purified water, draws the retrieval and utilization.
Raw material PX in the PTA production process is used as an extracting agent in the extraction tower 1, the raw material PX and PTA refined mother liquor are in countercurrent contact in the extraction tower 1, the p-toluic acid is removed under the action of a mass transfer element in the extraction tower 1, and PX containing the p-toluic acid is extracted from the top of the extraction tower 1 and enters an oxidation unit. Wherein, the mass transfer element in the extraction tower 1 adopts anti-blocking filler, the operating pressure of the extraction tower 1 is 0.2 MPaG-2.0 MPaG, and the operating temperature of the extraction tower 1 is 50-170 ℃.
The stripping tower 2 removes PX in PTA refined mother liquor through stripping operation, a reboiler is arranged at a tower kettle of the stripping tower 2, stripping heat is provided through low-pressure steam, mixed steam of the PX and part of water is extracted from the top of the stripping tower 2, and the refined mother liquor with the PX removed is extracted from the tower kettle of the stripping tower 2. Wherein, the mass transfer element of the stripping tower 2 adopts a conventional tower tray, the operating pressure of the stripping tower 2 is 0.02 MPaG-0.2 MPaG, and the operating temperature of the stripping tower 2 is 105-120 ℃.
The PTA refined mother liquor with PX removed enters the middle part of a rectifying tower 3, the rectifying tower 3 concentrates the PTA refined mother liquor through rectification operation, separation of water and heavy component impurities is realized in the rectifying tower 3, COD in purified water is further reduced, high-purity purified water is obtained at the top of the rectifying tower 3, and concentrated refined mother liquor residual liquid is extracted from a tower kettle of the rectifying tower 3 and is sent to a wastewater treatment device. Wherein the operating pressure of the rectifying tower 3 is-0.04 MPaG to-0.06 MPaG, the operating temperature of the rectifying tower 3 is 50-90 ℃, and the compression ratio of the heat pump compressor 4 is 1.5-2.5.
The utility model provides a purifier adopts raw materials PX to extract the p-toluic acid in the waste water for the solvent, can return oxidation reactor together PX and p-toluic acid, just can turn into product PTA with p-toluic acid through degree of depth oxidation, has saved PX's regeneration step, reduces the extraction cost, can purify the PTA waste water again on the one hand, makes it return the hydrofining process as the reuse of solvent water, still can retrieve p-toluic acid. In addition, the heat pump rectification is realized through the rectifying tower 3, the heat pump compressor 4 and the tower kettle reboiler 5, the refined mother liquor with the p-toluic acid and PX removed is refined, high-quality purified water is obtained on the premise of not consuming steam, the recycling of most of water is realized, the energy consumption is reduced, and the water resource is saved. In addition, after separation of heat pump rectification, most of refined mother liquor is extracted from the standby cooler 6 in the form of purified water and is recycled to the oxidation working section of the PTA device, and only a small amount of concentrated solution is extracted from the tower kettle of the rectification tower 3 and is sent to a wastewater treatment device, so that the wastewater treatment capacity is reduced, and the wastewater treatment cost is saved. .
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (6)
1. The utility model provides a purifier of PTA refined mother liquor which characterized in that: comprises that
The extraction tower is used for extracting the p-toluic acid in the PTA refining mother liquor through PX;
the stripping tower is used for stripping the PTA refined mother liquor from which the p-methylbenzoic acid is removed and removing PX in the PTA refined mother liquor;
the rectifying tower is used for rectifying the PTA refined mother liquor from which PX is removed and concentrating the PTA refined mother liquor;
the PTA refined mother liquor with PX removed enters the middle part of the rectifying tower, the top of the rectifying tower is connected with a heat pump compressor through a pipeline, a tower kettle of the rectifying tower is connected with a tower kettle reboiler through a pipeline, the heat pump compressor is used for heating a gas phase from the rectifying tower, and the tower kettle reboiler is used for heating a liquid phase from the rectifying tower by using the heated gas phase as a heat source.
2. The purification apparatus of PTA refining mother liquor according to claim 1, wherein: a backup cooler is included for cooling the gas phase flowing from the kettle reboiler.
3. The purification apparatus of PTA refining mother liquor according to claim 1, wherein: the mass transfer element in the extraction tower is an anti-clogging filler or an anti-clogging tower tray, the operating pressure of the extraction tower is 0.2 MPaG-2.0 MPaG, and the operating temperature of the extraction tower is 50-170 ℃; PX and PTA refined mother liquor are in countercurrent contact in the extraction tower.
4. The purification apparatus of PTA refining mother liquor according to claim 1, wherein: the mass transfer element of the stripping tower is a filler or a tower tray, the operating pressure of the stripping tower is 0.02 MPaG-0.2 MPaG, and the operating temperature of the stripping tower is 105-120 ℃.
5. The purification apparatus of PTA refining mother liquor according to claim 1, wherein: the operating pressure of the rectifying tower is-0.04 MPaG to-0.06 MPaG, and the operating temperature of the rectifying tower is 50-90 ℃.
6. The purification apparatus of PTA refining mother liquor according to claim 1, wherein: the compression ratio of the heat pump compressor is 1.5-2.5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120197934.4U CN214299725U (en) | 2021-01-25 | 2021-01-25 | Purification device for PTA (purified terephthalic acid) refining mother liquor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120197934.4U CN214299725U (en) | 2021-01-25 | 2021-01-25 | Purification device for PTA (purified terephthalic acid) refining mother liquor |
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| CN214299725U true CN214299725U (en) | 2021-09-28 |
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| CN202120197934.4U Active CN214299725U (en) | 2021-01-25 | 2021-01-25 | Purification device for PTA (purified terephthalic acid) refining mother liquor |
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2021
- 2021-01-25 CN CN202120197934.4U patent/CN214299725U/en active Active
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| PE01 | Entry into force of the registration of the contract for pledge of patent right |
Denomination of utility model: Purification device for PTA refining mother liquor Effective date of registration: 20220128 Granted publication date: 20210928 Pledgee: Bank of China Limited Tianjin Nankai sub branch Pledgor: TIANJIN HUIZHU HENGSHENG TECHNOLOGY Co.,Ltd. Registration number: Y2022110000026 |
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| PE01 | Entry into force of the registration of the contract for pledge of patent right | ||
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Date of cancellation: 20230512 Granted publication date: 20210928 Pledgee: Bank of China Limited Tianjin Nankai sub branch Pledgor: TIANJIN HUIZHU HENGSHENG TECHNOLOGY Co.,Ltd. Registration number: Y2022110000026 |
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| PC01 | Cancellation of the registration of the contract for pledge of patent right |