PGMEA rectification purification system and rectification purification method

Abstract

The invention discloses a PGMEA rectification and purification system and method, and the system comprises a precipitation kettle which is used for storing a recovered PGMEA solution until solid impurities in the PGMEA solution precipitate in an upper layer separation suspension liquid; a filter; a condenser; and a dehydrating tower. According to the PGMEA rectification purification system and the rectification purification method, a PGMEA product containing high-content metal ions and a mixture are mixed by a dehydrating tower and then transferred into the dehydrating tower to be dehydrated, the dehydrated product is transferred into rectification equipment through a circulating pump, in the tower, PGMEA migrates upwards, and in the rectification tower, the PGMEA product is separated from the mixture; the heavy components and the metal ions return to the main tower through mass transfer separation and are discharged from the tower kettle for re-rectification, a high-concentration product is extracted from the tower top, and the extracted product enters an ion exchange resin bed to further remove the metal ions, so that a PGMEA product with low metal ion content can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of reagent distillation purification, in particular to a PGMEA distillation purification system and a distillation purification method. Background Art

[0002] PGMEA, also known as propylene glycol methyl ether acetate, is a high-grade solvent. Its molecules contain both ether bonds and carbonyl groups. The carbonyl groups form an ester structure and also contain alkyl groups. In the same molecule, there are both non-polar parts and polar parts. The functional groups of these two parts not only restrict and repel each other, but also play their own inherent roles. It is widely used in the fields of coatings, plastics and chemicals. In addition, it can be used in the production of photoresists as TFT-LCD photoresist thinners, photoresist removers, strippers, IC cleaning agents, photoresist removal buffers, etching processes and other chemical products requiring special specifications. It can also be used as a solvent for inks, textile dyes, textile oils, and cleaning agents in the production of liquid crystal displays. It has a certain solubility for both non-polar and polar substances. At the same time, in order to avoid waste of resources, PGMEA in wastewater is usually recovered and purified. After searching, it was found that the typical PGMEA distillation purification in the prior art is For example, the publication discloses a method for purifying PGMEA from PGMEA waste liquid. The PGMEA waste liquid mainly contains impurities such as PGME (propylene glycol methyl ether), ketone compounds, benzene compounds, ethoxy ester compounds, methoxy ester compounds, water, solid resistors, electronic components, etc. The composition and content of the waste liquid vary widely. The present invention targets the PGMEA waste liquid generated in the electronics industry. After the collected waste solvent is preliminarily filtered, it enters a raw material settling kettle to remove settleable solid impurities. After settling, the supernatant enters a distillation tower equipped with a vacuum pump to remove difficult-to-handle low-boiling and high-boiling impurities. The crude target product produced by the distillation tower enters a distillation tower for further distillation. Its main feature is that a target product with a purity greater than 95% is obtained, and the highest purity can reach 99%.

[0003] In summary, the existing purification methods are mainly aimed at removing impurities in PGMEA, but are unable to remove metal ions in the solvent. The metal ion content in the recovered PGMEA is too high, which affects the use of circuit boards in electronic products and narrows the range of PGMEA. In view of the above problems, the existing methods need to be improved. Summary of the Invention

[0004] The object of the present invention is to provide a PGMEA distillation purification system and a distillation purification method to solve the problem that the existing purification method proposed in the above background technology is mainly aimed at removing impurities in PGMEA, but cannot remove metal ions in the solvent, and the metal ions in the recovered PGMEA are too high, thereby affecting the use of circuit boards in electronic products, and further narrowing the range of PGMEA.

[0005] To achieve the above object, the present invention provides the following technical solution: a PGMEA distillation purification system and a distillation purification method, comprising:

[0006] A precipitation kettle is used to store the recovered PGMEA solution until solid impurities in the PGMEA solution are precipitated into the upper layer to separate the supernatant;

[0007] A filter is used to filter the suspension, and the filtered suspension enters the distillation tower for heating and distillation;

[0008] Condenser, which is used to condense the steam generated during the distillation process of the distillation tower and thereby obtain the material carried in the steam. There are two sets of condensers;

[0009] A distillation tower, wherein the distillation tower is used to heat and perform secondary distillation on the crude product distilled from the distillation tower;

[0010] The dehydration tower is used to dehydrate the PGMEA product obtained by secondary distillation of mixed related materials in the tower, and to perform resin exchange on the dehydrated material to remove the metal ions.

[0011] Preferably, the PGMEA solution in the precipitation kettle is placed in a static precipitation manner, and the static precipitation time is 1 h to 1.5 h.

[0012] Preferably, the filtering process of the filter is 1-2 times, and the filter adopts a multi-media filter. The filter adopts a nano-scale filter element for filtering, and the material of the nano-scale filter element is polytetrafluoroethylene.

[0013] Preferably, the distillation tower and the rectification tower are both heated by steam, and the distillation tower is a packed tower, and the packing inside the distillation tower is 5-8m, and the reflux ratio is adjusted to 3-4:1.

[0014] Preferably, the distillation tower adopts a staged heating method, and the heating temperature of the first stage is 45-100°C, the duration is 10-20 minutes, the heating temperature of the second stage is 110-120°C, the duration is 20-30 minutes, and the heating temperature of the third stage is 130-170°C, the duration is 20-30 minutes.

[0015] Preferably, the distillation tower includes a first-stage vacuum distillation, a second-stage vacuum distillation, an atmospheric distillation and a third-stage vacuum distillation performed in sequence in a multi-stage distillation manner, and the distillation pressure of the distillation tower is controlled at 0.005-0.025 MPa, the reflux ratio is 1:5, the distillation temperature is 110-180°C, and the number of tower plates is 12-16.

[0016] Preferably, the top pressure of the dehydration tower is 0.1 MPa, the top temperature is 80-90° C., and the reflux ratio in the tower is 1.5-3. After dehydration, the product is distilled again and enters the ion exchange resin bed to further remove metal ions.

[0017] Preferably, a PGMEA distillation purification method is applied to the above-mentioned PGMEA distillation purification system, characterized in that it comprises the following steps:

[0018] S1, static sedimentation stage: the PGMEA to be treated is recovered and allowed to stand to precipitate and separate solid impurities. After separation, the upper supernatant is filtered and transferred to the interior of the distillation tower;

[0019] S2, heating and distillation stage: The supernatant entering the distillation tower is heated by steam to obtain a crude product. At the same time, the water vapor generated during the heating process is condensed by a set of condensers and then refluxed into the distillation tower;

[0020] S3, secondary distillation stage: the crude product is heated again, and the water vapor generated during the heating process is condensed by another set of condensers to obtain a low-purity PGMEA product;

[0021] S4, dehydration and purification stage: The PGMEA product containing high metal ion content is mixed with the mixture and then transferred to the inside of the dehydration tower for dehydration. After dehydration, it is distilled again, and the high-concentration product is extracted from the top of the tower. The extracted product enters the ion exchange resin bed to further remove metal ions to obtain a PGMEA product with low metal ion content.

[0022] Preferably, the entrainer during dehydration in the S4 dehydration and purification stage is toluene, and the ion exchange resin bed is a weakly acidic cation exchange resin such as Amberlite IRC83H cation exchange resin.

[0023] Preferably, the S4 dehydration and purification stage is transferred to the middle part of the distillation equipment by a circulation pump, the light and heavy components are separated, the unreacted raw material propylene glycol methyl ether, acetic acid and a trace amount of water mixture is distilled from the top of the tower and returned to the reactor for recycling, and the gaseous mixture carrying metal ions and heavy components enters the bottom of the distillation side line tower through a connecting pipeline. In the tower, PGMEA migrates upward, and the heavy components cooperate with the metal ions to return to the main tower through mass transfer separation and are discharged from the bottom of the tower.

[0024] Compared with the prior art, the beneficial effects of the present invention are: the PGMEA distillation purification system and distillation purification method,

[0025] The present invention can effectively solve the problem that the existing purification method mainly removes impurities in PGMEA but cannot remove metal ions in the solvent, and the metal ions in the recovered PGMEA are too high, thereby affecting the use of circuit boards in electronic products and further narrowing the range of PGMEA. The dehydration tower mixes a PGMEA product containing a high content of metal ions with a mixture and transfers it to the interior of the dehydration tower for dehydration. After dehydration, the mixture is transferred to the middle part of the distillation equipment by a circulating pump, and light and heavy components are separated. The unreacted raw material propylene glycol methyl ether, acetic acid and a trace amount of water mixture is distilled from the top of the tower and returned to the reactor for recycling. The gaseous mixture entrained with metal ions and heavy components enters the bottom of the distillation side-line tower through a connecting pipeline. In addition, in the tower, PGMEA migrates upward, and the heavy components and metal ions are separated by mass transfer and returned to the main tower and discharged from the tower bottom for re-distillation. The high-concentration product is extracted from the top of the tower. The extracted product enters an ion exchange resin bed for further removal of metal ions, thereby obtaining a PGMEA product with a low metal ion content. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the purification process of the present invention;

[0027] Figure 2 Schematic diagram of the overall structure of the system of the present invention.

[0028] In the figure: 1. Precipitation kettle; 2. Filter; 3. Distillation tower; 4. Condenser; 5. Distillation tower; 6. Dehydration tower. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] See also Figure 1-2 The present invention provides a technical solution: a PGMEA distillation purification system and a distillation purification method.

[0031] Example 1

[0032] A PGMEA distillation and purification system, comprising:

[0033] The precipitation tank 1 is used to store the recovered PGMEA solution until the solid impurities in the PGMEA solution are precipitated to the upper layer to separate the supernatant;

[0034] Filter 2, filter 2 is used to filter the suspension, and the filtered suspension enters the distillation tower 3 for heating and distillation;

[0035] Condenser 4, condenser 4 is used to condense the steam generated during the distillation process of distillation tower 3, and thereby obtain the material carried in the steam. At the same time, two groups of condensers 4 are provided;

[0036] The distillation tower 5 is used to heat and perform secondary distillation on the crude product distilled from the distillation tower 3;

[0037] Dehydration tower 6 is used to dehydrate the PGMEA product obtained by secondary distillation of mixed related materials in the tower, and to perform resin exchange on the dehydrated material to remove the metal ions.

[0038] The PGMEA solution in the precipitation tank 1 is placed in a static precipitation manner, and the static precipitation time is 1 h to 1.5 h.

[0039] In a further embodiment, the filtering process of the filter 2 is 1-2 times, and the filter 2 adopts a multi-media filter, and the filter 2 adopts a nano-scale filter element for filtering, and the material of the nano-scale filter element is polytetrafluoroethylene.

[0040] In a further embodiment, the distillation tower 3 and the rectification tower 5 are both heated by steam, and the distillation tower 3 is a packed tower, and the packing inside the distillation tower 3 is 5-8m, and the reflux ratio is adjusted to 3-4:1.

[0041] In a further embodiment, the distillation tower 3 adopts a staged heating method, and the heating temperature of the first stage is 45-100°C, the duration is 10-20 minutes, the heating temperature of the second stage is 110-120°C, the duration is 20-30 minutes, and the heating temperature of the third stage is 130-170°C, the duration is 20-30 minutes.

[0042] In a further embodiment, the distillation tower 5 includes a first-stage vacuum distillation, a second-stage vacuum distillation, an atmospheric distillation and a third-stage vacuum distillation performed in sequence using a multi-stage distillation method. At the same time, the distillation pressure of the distillation tower 5 is controlled at 0.005-0.025 MPa, the reflux ratio is 1:5, the distillation temperature is 110-180°C, the number of tower plates is 12-16, and the distillation tower 5 is provided with multiple feed points. Different feed points are selected according to the different components and content of the waste liquid, and the stripping section and the distillation section can be flexibly changed.

[0043] In a further embodiment, the top pressure of the dehydration tower 6 is 0.1 MPa, the top temperature is 80-90° C., the reflux ratio in the tower is 1.5-3, and after dehydration, the product is distilled again to produce the product, and the product enters the ion exchange resin bed to further remove metal ions. A condenser 4 is provided at the top of the dehydration tower 6, connected to the phase separation tank, the entrainer material pipeline is connected to the phase separation tank, the top of the entrainer phase layer is provided with an extractant reflux pipeline, the bottom of the aqueous phase layer is connected to the production pipeline, and the tower bottom is provided with a reboiler for steam heating; a circulating pump is provided at the front end of the dehydrated material pipeline to pump the material into the middle of the distillation equipment; a condenser 4 is provided at the top of the distillation equipment, part of the light component mixture flows into the production pipeline, and part returns to the top of the tower through the reflux pipeline, and the tower bottom is provided with a reboiler, and the heating method is the same; a condenser 4 is provided at the top of the side tower, and part of the PGMEA crude product flows into the production pipeline, and part returns to the top of the tower through the reflux pipeline; the dehydration tower 6, the distillation equipment and the top of the side tower are all cooled by cooling water.

[0044] Example 2

[0045] This embodiment is a further description of the above embodiment. It should be understood that this embodiment includes all the above technical features and is further described in detail.

[0046] In a further embodiment, a PGMEA distillation purification method is applied to the above-mentioned PGMEA distillation purification system, comprising the following steps:

[0047] S1, static sedimentation stage: the PGMEA to be treated is recovered and allowed to stand to precipitate and separate solid impurities. After separation, the upper supernatant is filtered and transferred to the interior of the distillation tower 3;

[0048] S2, heating and distillation stage: The suspension entering the distillation tower 3 is heated by steam heating to obtain a crude product. At the same time, the water vapor generated during the heating process is condensed by a set of condensers 4 and then refluxed into the distillation tower 3;

[0049] S3, secondary distillation stage: the crude product is heated again, and the water vapor generated during the heating process is condensed by another set of condensers 4 to obtain a low-purity PGMEA product;

[0050] S4, dehydration and purification stage: The PGMEA product containing a high content of metal ions is mixed with the mixture and then transferred to the interior of the dehydration tower 6 for dehydration. After dehydration, it is distilled again, and the high-concentration product is extracted from the top of the tower. The extracted product enters the ion exchange resin bed to further remove metal ions to obtain a PGMEA product with a low metal ion content.

[0051] In a further embodiment, the entrainer during the dehydration in the S4 dehydration purification stage is toluene, and the ion exchange resin bed is a weakly acidic cation exchange resin such as Amberlite IRC83H cation exchange resin.

[0052] In a further embodiment, the S4 dehydration and purification stage is transferred to the middle part of the distillation equipment through a circulation pump, the light and heavy components are separated, and the unreacted raw material propylene glycol methyl ether, acetic acid and a trace amount of water mixture is distilled from the top of the tower and returned to the reactor for recycling. The gaseous mixture carrying metal ions and heavy components enters the bottom of the distillation side line tower through a connecting pipeline. In the tower, PGMEA migrates upward, and the heavy components cooperate with the metal ions to return to the main tower through mass transfer separation and are discharged from the bottom of the tower.

[0053] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A PGMEA distillation and purification system, characterized in that ,include: A precipitation kettle (1), wherein the precipitation kettle (1) is used to store the recovered PGMEA solution until solid impurities in the PGMEA solution are precipitated to the upper layer to separate the suspension; A filter (2), wherein the filter (2) is used to filter the suspension, and the filtered suspension enters a distillation tower (3) for heating and distillation; A condenser (4), wherein the condenser (4) is used to condense the steam generated during the distillation process of the distillation tower (3) to obtain the material carried in the steam, and two groups of condensers (4) are provided; A distillation tower (5), wherein the distillation tower (5) is used to heat and perform secondary distillation on the crude product distilled from the distillation tower (3); A dehydration tower (6) is used to dehydrate the PGMEA product obtained by secondary distillation of mixed related materials in the tower, and to perform resin exchange on the dehydrated material to remove metal ions.

2. A PGMEA distillation and purification system according to claim 1, characterized in that: The PGMEA solution in the precipitation kettle (1) is subjected to static precipitation, and the static precipitation time is 1h-1.5h.

3. A PGMEA distillation and purification system according to claim 1, characterized in that: The filtering process of the filter (2) is 1-2 times, and the filter (2) adopts a multi-media filter. The filter (2) adopts a nano-scale filter element for filtering, and the material of the nano-scale filter element is polytetrafluoroethylene.

4. A PGMEA distillation and purification system according to claim 1, characterized in that: The distillation tower (3) and the rectification tower (5) are both heated by steam, and the distillation tower (3) is a packed tower. The packing inside the distillation tower (3) is 5-8m, and the reflux ratio is adjusted to 3-4:

1.

5. A PGMEA distillation and purification system according to claim 1, characterized in that: The distillation tower (3) adopts a staged heating method, and the heating temperature of the first stage is 45-100°C, the duration is 10-20 minutes, the heating temperature of the second stage is 110-120°C, the duration is 20-30 minutes, and the heating temperature of the third stage is 130-170°C, the duration is 20-30 minutes.

6. A PGMEA distillation and purification system according to claim 1, characterized in that: The distillation tower (5) comprises a first-stage vacuum distillation, a second-stage vacuum distillation, a normal pressure distillation and a third-stage vacuum distillation which are carried out in sequence in a multi-stage distillation manner. Meanwhile, the distillation pressure of the distillation tower (5) is controlled at 0.005-0.025 MPa, the reflux ratio is 1:5, the distillation temperature is 110-180°C, and the number of tower plates is 12-16.

7. A PGMEA distillation and purification system according to claim 1, characterized in that: The top pressure of the dehydration tower (6) is 0.1 MPa, the top temperature is 80-90°C, and the reflux ratio in the tower is 1.5-3. After dehydration, the product is distilled again and enters the ion exchange resin bed to further remove metal ions.

8. A PGMEA distillation and purification method, applied to the PGMEA distillation and purification system according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, static sedimentation stage: recover the PGMEA to be treated and let it stand to precipitate and separate solid impurities. After separation, the upper suspension is filtered and transferred to the inside of the distillation tower (3); S2, heating distillation stage: the suspension entering the distillation tower (3) is heated by steam heating to obtain a crude product, and the water vapor generated during the heating process is condensed by a group of condensers (4) and then refluxed into the distillation tower (3); S3, secondary distillation stage: the crude product is heated again, and the water vapor generated during the heating process is condensed by another set of condensers (4) to obtain a low-purity PGMEA product; S4, dehydration and purification stage: the PGMEA product containing high content of metal ions is mixed with the mixture and then transferred to the interior of the dehydration tower (6) for dehydration. After dehydration, it is distilled again, and the high concentration product is extracted from the top of the tower. The extracted product enters the ion exchange resin bed to further remove metal ions, thereby obtaining a PGMEA product with low metal ion content.

9. A PGMEA distillation and purification method according to claim 8, characterized in that: The entrainer during dehydration in the S4 dehydration and purification stage is toluene, and the ion exchange resin bed is a weakly acidic cation exchange resin, namely Amberlite IRC83H cation exchange resin.

10. A PGMEA distillation and purification method according to claim 8, characterized in that: The S4 dehydration and purification stage is transferred to the middle part of the distillation equipment through a circulation pump, and the light and heavy components are separated. The unreacted raw materials propylene glycol methyl ether, acetic acid and a trace amount of water mixture are distilled from the top of the tower and returned to the reactor for recycling. The gaseous mixture carrying metal ions and heavy components enters the bottom of the distillation side line tower through a connecting pipeline. In the tower, PGMEA migrates upward, and the heavy components and metal ions are separated by mass transfer and returned to the main tower and discharged from the bottom of the tower.

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