Magnetic particle filtering system for electronic grade polyethylene glycol production

Abstract

The invention discloses a magnetic particle filtering system for electronic grade polyethylene glycol production, and belongs to the technical field of polyethylene glycol production process improvement, the magnetic particle filtering system comprises a reactor, a front filtering device is arranged at the front end of the reactor, the front filtering device is connected with the reactor through a pipeline, and the front filtering device comprises a filtering unit A and a filtering unit B; the filter unit B is connected to the filter unit A in parallel through a pipeline. The filter screen adopts a cylindrical filter screen, the bottom of the cylindrical filter screen is of a net-shaped closed structure, the upper part of the cylindrical filter screen is of an opening structure with a diagonal plane, and a feed port is higher than the front end of the upper part of the cylindrical filter screen and lower than the rear end of the upper part of the cylindrical filter screen; the rear end of the upper part of the barrel-shaped filter screen is higher than the front end of the upper part of the barrel-shaped filter screen, so that non-metal impurities in ethylene glycol can be more comprehensively intercepted, the flux of an ethylene glycol solution is increased, the filtering speed of ethylene glycol is increased, and the filtering efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of polyethylene glycol production process improvement technology, specifically a magnetic particle filtration system for the production of electronic-grade polyethylene glycol. Background Technology

[0002] Existing industrial-grade PEG products suffer from high levels of metal ions (such as Na+, K+, Fe3+, etc.) and magnetic particles, failing to meet the requirements for electronic-grade applications. In traditional processes, metal ion content is primarily controlled by catalyst ratio, but this control lacks precision. Magnetic particle filtration often employs single-stage ordinary filters, resulting in low filtration efficiency (magnetic particle content is typically maintained at 200-300 ppm) and hindering filter maintenance during continuous production. The multiple technical challenges exposed in the actual production of electronic-grade polyethylene glycol (PEG) are mainly concentrated in key areas such as raw material purity, molecular uniformity, preparation of functional derivatives, process scale-up, and stability control. Specifically:

[0003] 1. Controlling the purity and impurities of raw materials is difficult.

[0004] Trace impurities have a significant impact: PEG is polymerized from ethylene oxide, and impurities such as trace amounts of moisture, unreacted monomers, and byproducts can directly affect the stability of downstream drug modification reactions and the quality of the final product.

[0005] High-purity raw materials have high barriers to entry: electronic-grade / pharmaceutical-grade PEG needs to have a purity of over 99% and a dispersion of less than 1.05, and there are very few companies in the world that can mass-produce cGMP-grade PEG raw materials.

[0006] Uneven molecular weight distribution (high dispersibility)

[0007] Monodisperse PEG is difficult to prepare: PEG obtained by traditional polymerization methods is a polydisperse system (with a wide molecular weight distribution), which makes it difficult to accurately quantify when modifying drugs, resulting in poor batch-to-batch consistency and affecting the consistency of drug efficacy.

[0008] Separation and purification are complex: polydisperse PEG needs to be repeatedly purified by means of gel permeation chromatography (GPC), which is cumbersome and costly.

[0009] 3. Lack of quality control and standardization

[0010] Lack of unified quality control standards: There are no unified industry standards for electronic grade PEG in terms of particle size, functional group substitution degree, residual solvent, heavy metal content, etc., which leads to long verification cycles for downstream applications.

[0011] Poor batch-to-batch consistency: Even from the same manufacturer, different batches of PEG may have significant differences in functional group density and molecular weight distribution, affecting the reliability of high-end electronic devices. Summary of the Invention

[0012] To address the technical problems mentioned in the background section, the present invention provides a magnetic particle filtration system for the production of electronic-grade polyethylene glycol, employing the following technical solution:

[0013] It includes a reactor, and a pre-filtration device is installed at the front end of the reactor. The pre-filtration device is connected to the reactor through a pipeline. The pre-filtration device includes a filter unit A and a filter unit B connected in parallel to filter unit A through a pipeline.

[0014] Furthermore, filter unit A includes a housing with an inlet at the upper part of one end, to which a pipeline is connected. An outlet is located at the lower part of the other end of the housing and is connected to the reactor via a pipeline. A cylindrical filter screen is fixedly connected inside the housing, with a closed mesh structure at the bottom and an open structure with a slanted cut at the top. The inlet is higher than the front end of the upper part of the cylindrical filter screen and lower than the rear end. Several neodymium iron boron permanent magnet rods are fixedly connected to the inner wall of the housing, suspended inside the cylindrical filter screen. Filter unit B has the same structure as filter unit A.

[0015] Furthermore, switching valves a, b, c, and d are connected to the pipelines on both sides of filter unit A, and switching valves e and f are connected to filter unit B in parallel on the pipelines of filter unit A. A DCS control system is also connected to the pipelines on both sides of filter unit A, and an alarm is connected to the DCS control system.

[0016] Furthermore, the magnetic field strength of the neodymium iron boron permanent magnet rod is ≥3000Gs, and the spacing between the neodymium iron boron permanent magnet rods is 20mm.

[0017] Furthermore, the housing withstands a pressure of 0.6 MPa, and the differential pressure alarm threshold is 0.15 MPa.

[0018] Furthermore, the reactor is connected to a delivery pump via a pipeline, the delivery pump is connected to a heat exchanger via a pipeline, and the heat exchanger is connected to the reactor via a pipeline.

[0019] Furthermore, the pipeline where the delivery pump is located is also connected to another pipeline, and a neutralization vessel is connected to the neutralization vessel via a pipeline. A feed pump is connected to the neutralization vessel via a pipeline, and a post-filtration device is connected to the feed pump via a pipeline. The filtration device includes a C filtration unit, which has the same structure as the A filtration unit.

[0020] The present invention has the following advantages:

[0021] 1. Through the synergistic design of magnetic filtration using neodymium iron boron permanent magnet rods and mechanical filtration using cylindrical filter screens, it can remove ferromagnetic particles from ethylene glycol raw materials and intercept non-magnetic impurities, forming a gradient purification system that makes the filtration of ethylene glycol raw materials more thorough.

[0022] 2. The filter screen adopts a cylindrical filter screen with a closed mesh structure at the bottom and an open structure with a slanted cut at the top. The feed inlet is higher than the front end of the upper part of the cylindrical filter screen but lower than the rear end. This design increases the contact area between the ethylene glycol raw material and the cylindrical filter screen (the rear end of the upper part of the cylindrical filter screen is higher than the front end), which can more comprehensively intercept non-metallic impurities in the ethylene glycol, increase the throughput of the ethylene glycol solution, improve the filtration speed of ethylene glycol, and improve filtration efficiency.

[0023] 3. Filter unit B is connected in parallel to filter unit A via pipeline. If filter unit A is overloaded and the pressure difference exceeds the set value, it will automatically switch to filter unit B to continue filtration. Filter unit A can be cleaned, which ensures continuous filtration of diethanol, avoids delaying the filtration process, and improves work efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process of the present invention;

[0025] Figure 2 For the present invention Figure 1 A magnified view of a portion of point a;

[0026] Figure 3 This is a structural diagram of the A filter unit of the present invention;

[0027] Figure 4 For the present invention Figure 1 A magnified view of a section at point b.

[0028] Attached Figures: 1. Reactor; 2. Shell; 3. Inlet; 4. Outlet; 5. Cylindrical Filter Screen; 6. Neodymium Iron Boron Permanent Magnet; 7. Switching Valve a; 8. Switching Valve b; 9. Switching Valve c; 10. Switching Valve d; 11. Switching Valve e; 12. Switching Valve f; 13. DCS Control System; 14. Alarm; 15. Transfer Pump; 16. Heat Exchanger; 17. Neutralization Tank; 18. Feed Pump. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Please refer to Figure 1-4This invention provides a magnetic particle filtration system for the production of electronic-grade polyethylene glycol, comprising a reactor 1, a pre-filtration device at the front end of the reactor 1, the pre-filtration device being connected to the reactor 1 via a pipeline, the pre-filtration device including a filter unit A, to which ethylene glycol enters through the pipeline, the filter unit A filters out both technical particles and non-metallic particles in the ethylene glycol, and a filter unit B is connected in parallel to the filter unit A via a pipeline, automatically shutting down and switching to the filter unit B for filtration when the filter unit A is overloaded.

[0031] Filtering unit A includes a housing 2. An inlet 3 is provided at the upper part of one end of the housing 2, and a pipeline is connected to the inlet 3. An outlet 4 is provided at the lower part of the other end of the housing 2. Ethylene glycol enters the housing 2 through the pipeline and is filtered. The filtered ethylene glycol is discharged through the outlet 4. The outlet 4 is connected to the reactor 1 through a pipeline. The ethylene glycol discharged from the outlet 4 enters the reactor 1 through the pipeline to react.

[0032] A cylindrical filter screen 5 is fixedly connected inside the housing 2. The bottom of the cylindrical filter screen 5 is a closed mesh structure, and the top is an open structure with a beveled surface. The feed inlet 3 is higher than the front end of the upper part of the cylindrical filter screen 5 and lower than the rear end of the upper part of the cylindrical filter screen 5. In this way, when ethylene glycol enters the housing 2, it can ensure that the ethylene glycol can enter the cylindrical filter screen 5, and the contact area between the ethylene glycol and the cylindrical filter screen 5 can be increased, thereby increasing the flow rate of ethylene glycol after filtration and improving the filtration efficiency.

[0033] Several neodymium iron boron permanent magnet rods 6 are fixedly connected to the inner wall of the housing 2. The neodymium iron boron permanent magnet rods 6 are suspended inside the cylindrical filter screen 5. When ethylene glycol enters the cylindrical filter screen 5, the ethylene glycol comes into contact with the neodymium iron boron permanent magnet rods 6, and the metal particles in the ethylene glycol are adsorbed by the neodymium iron boron permanent magnet rods 6. The structure of the B filter unit is the same as that of the A filter unit, so the B filter unit will not be described in detail. It is only used when the A filter unit is overloaded.

[0034] Switching valves a7, b8, c9, and d10 are connected to the pipelines on both sides of filter unit A. Switching valves a7 and d10 act as switches for the pipelines of filter unit A and filter unit B as a whole. Switching valves b8 and c9 control the switching on and off of filter unit A. Filter unit B is connected in parallel to filter unit A via switching valves e11 and f12. Switching valves e11 and f12 control the switching on and off of filter unit B. DCS control system 13 is also connected to the pipelines on both sides of filter unit A. An alarm 14 is connected to DCS control system 13. DCS control system is a distributed control system. When filter unit A is overloaded, alarm 14 sounds, controls switching valves b8 and c9 to close, and controls switching valves e11 and f12 to open, so that ethylene glycol is switched from entering filter unit A to entering filter unit B for filtration.

[0035] The magnetic field strength of the neodymium iron boron permanent magnet rod 6 is ≥3000Gs. The spacing between the neodymium iron boron permanent magnet rods 6 is 20mm. The neodymium iron boron permanent magnet rods 6 have excessively strong magnetic force and are relatively close to each other, which can strongly and effectively adsorb metal particles in ethylene glycol ester.

[0036] Housing 2 has a pressure resistance of 0.6 MPa and a differential pressure alarm threshold of 0.15 MPa. When the differential pressure inside housing 2 exceeds 0.15 MPa, filter unit A is turned off and switched to filter unit B.

[0037] Reactor 1 is connected to a transfer pump 15 via a pipeline and a heat exchanger 16 via a pipeline. Heat exchanger 16 is connected to reactor 1 via a pipeline. A portion of the ethylene glycol produced in reactor 1 after reaction is sent to heat exchanger 16 via transfer pump 15 for heating and then sent back to reactor 1, thus ensuring that the ethylene glycol can react fully in reactor 1.

[0038] The pipeline containing the transfer pump 15 is also connected to another pipeline, which in turn connects to a neutralization vessel 17. A feed pump 18 is connected to the neutralization vessel 17 via a pipeline, and the feed pump 18 is connected to a post-filtration device via a pipeline. The filtration device includes a C filtration unit, which has the same structure as the A filtration unit. The transfer pump 15 sends another portion of ethylene glycol into the neutralization vessel 17 for neutralization reaction. Since the neutralizing agent lactic acid is added to the neutralization vessel 17 during the neutralization reaction, and metal particles are generated due to the wear of the stirring blades during stirring, new metal and non-metal impurities will be generated in the ethylene glycol after the neutralization reaction. Therefore, it is necessary to send the ethylene glycol to the C filtration unit again via the feed pump 18 for filtration of metal and non-metal particles.

[0039] The working principle of this invention is as follows: High-pressure ethylene glycol solution enters the shell 2 through the inlet 3 via a pipeline and comes into contact with the neodymium iron boron permanent magnet rod 6. Metal particles in the ethylene glycol are adsorbed by the neodymium iron boron permanent magnet rod 6, and then non-metallic impurities in the ethylene glycol are intercepted by the cylindrical filter screen 5. The filtered ethylene glycol enters the outlet 4 through the cylindrical filter screen 5 and is sent to the reactor 1 via a pipeline for reaction. The purity of the filtered ethylene glycol reaches 99.95%.

[0040] Ethylene glycol raw material specifications: metal particle content ≤0.1%; Ethylene glycol after filtration specifications: ethylene glycol content ≥99.95%, metal particle content ≤0.02%.

[0041] Sampling and detection results: metal ions 42ppm, magnetic particles 28ppm, system pressure drop 0.07MPa, conforming to electronic grade PEG standards.

[0042] The produced electronic-grade PEG products meet the following specifications:

[0043] 1. Hydroxyl value (as KOH): 26.8~29.4; pH (5% aqueous solution): 5.0~7.0; Molecular weight: 3820~4180; Metal ion content: ≤50ppm; Metal particles ≤40.

[0044] 2. Hydroxyl value (calculated as KOH): 16.1~20.6; pH (5% aqueous solution): 5.0~7.0; Molecular weight: 5450~6950; Metal ion content: ≤50ppm; Metal particles ≤40.

[0045] This invention is simple to operate, convenient to use, and suitable for widespread promotion and application. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A magnetic particle filtration system for the production of electronic-grade polyethylene glycol, comprising a reactor (1), characterized in that, A pre-filter is provided at the front end of the reactor (1). The pre-filter is connected to the reactor (1) through a pipeline. The pre-filter includes filter unit A and filter unit B connected in parallel to filter unit A through a pipeline.

2. The magnetic particle filtration system for the production of electronic-grade polyethylene glycol according to claim 1, characterized in that, Filter unit A includes a housing (2), with an inlet (3) at the upper part of one end of the housing (2) and a pipeline connected to the inlet (3). An outlet (4) is provided at the lower part of the other end of the housing (2), and the outlet (4) is connected to the reactor (1) through a pipeline. A cylindrical filter screen (5) is fixedly connected inside the housing (2), and the bottom of the cylindrical filter screen (5) is a mesh-closed structure and the upper part is an obliquely cut open structure. The inlet (3) is higher than the upper front end of the cylindrical filter screen (5) and lower than the upper rear end of the cylindrical filter screen (5). Several neodymium iron boron permanent magnet rods (6) are fixedly connected to the upper inner wall of the housing (2). The neodymium iron boron permanent magnet rods (6) are suspended inside the cylindrical filter screen (5). Filter unit B has the same structure as filter unit A.

3. The magnetic particle filtration system for electronic-grade polyethylene glycol production according to claim 2, characterized in that, Switching valves a (7), b (8), c (9) and d (10) are connected to the pipelines on both sides of filter unit A. Switching valves e (11) and f (12) are connected to filter unit B in parallel on the pipelines of filter unit A. A DCS control system (13) is also connected to the pipelines on both sides of filter unit A. An alarm (14) is connected to the DCS control system (13).

4. The magnetic particle filtration system for the production of electronic-grade polyethylene glycol according to claim 2, characterized in that, The magnetic field strength of the neodymium iron boron permanent magnet rod (6) is ≥3000Gs, and the spacing between the neodymium iron boron permanent magnet rods (6) is 20mm.

5. A magnetic particle filtration system for the production of electronic-grade polyethylene glycol according to claim 2, characterized in that, The housing (2) has a pressure resistance of 0.6 MPa and a differential pressure alarm threshold of 0.15 MPa.

6. The magnetic particle filtration system for the production of electronic-grade polyethylene glycol according to claim 1, characterized in that, The reactor (1) is connected to a delivery pump (15) via a pipeline, and the delivery pump (15) is connected to a heat exchanger (16) via a pipeline. The heat exchanger (16) is connected to the reactor (1) via a pipeline.

7. A magnetic particle filtration system for the production of electronic-grade polyethylene glycol according to claim 6, characterized in that, The pipeline where the delivery pump (15) is located is also connected to a pipeline and a neutralization vessel (17) is connected to the pipeline. The neutralization vessel (17) is connected to a feed pump (18) via a pipeline. The feed pump (18) is connected to a post-filter via a pipeline. The filter includes a C filter unit, which has the same structure as the A filter unit.

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