An electronic grade trichloroethylene purification production device and a production process thereof

Abstract

This application relates to the technical field of distillation and purification equipment, and discloses an electronic-grade trichloroethylene purification production apparatus, including a distillation column. The distillation column has multiple longitudinally equidistantly arranged trays fixed inside. Several overflow frames are fixedly installed on the top of the trays, and a guide plate is fixedly installed at the bottom of the trays directly below the overflow frames. Gas guide pipes are fixedly installed on both sides of the bottom of the trays, and several gas guide grooves are opened on both sides of the gas guide pipes. The vapor flowing out through the gas guide pipes forms a cross-shaped contact mass transfer with the liquid film flowing vertically downwards along the guide plate. The cross-shaped flow generates high-frequency turbulent disturbances, causing continuous breakage and recombination of the gas-liquid interface, significantly shortening the mass transfer boundary layer thickness, reducing mass transfer resistance, and allowing for faster heat exchange after the liquid film is cut into a thin layer by the gas flow, reducing the risk of decomposition due to localized overheating. This apparatus is suitable for the high-efficiency distillation and purification of trichloroethylene.

Description

Technical Field

[0001] This application relates to the field of distillation and purification equipment technology, and in particular to an electronic-grade trichloroethylene purification production apparatus and its production process. Background Technology

[0002] Electronic-grade trichloroethylene is a high-purity organic chlorine solvent with a purity of over 99.999%, meeting the high standards required for semiconductor and precision electronics manufacturing. It possesses excellent solubility and stability, a boiling point of 87.1℃, and is a colorless and transparent liquid at room temperature. As a key process material, it is widely used in integrated circuits, flat panel displays, photovoltaics, and other fields to clean grease, particles, and organic residues from the surfaces of metal parts, electronic components, and silicon wafers, ensuring the cleanliness of the device's microstructure. Its precise cleaning efficiency and controllable physicochemical properties make it one of the core materials for ensuring the quality and reliability of electronic products.

[0003] Distillation columns are one of the commonly used devices in the production of electronic-grade trichloroethylene. They are used to remove low-boiling-point impurities such as dichloromethane and vinyl chloride from a mixed solution, as well as high-boiling-point impurities such as tetrachloroethylene and 1,1,1-trichloroethane, thereby purifying electronic-grade trichloroethylene.

[0004] For example, Chinese utility model patent application number 2021232915014 disclosed a distillation column for separating trichloroethylene and tetrachloroethylene on January 31, 2023. The column body has multiple trays installed longitudinally at intervals inside, and a tray weir is provided on one side of the tray. The tray spacing and number of trays can be adjusted according to actual production to ensure efficient operation of the distillation process. However, the gas phase flows horizontally on each tray, and the gas-liquid contact is insufficient, resulting in low distillation effect and efficiency.

[0005] For example, the Chinese utility model patent with application number 2024231376706, disclosed on November 28, 2025, discloses a distillation apparatus for separating trichloroethylene and tetrachloroethylene. It has active blades on the trays, which are driven to rotate by the pressure of the flowing gas phase. The rotation of the active blades drives the guide plate to rotate, which agitates and guides the liquid phase, so that the gas phase and liquid phase are fully mixed and contacted. However, under the long-term scouring of the gas phase, the bearings of the active impeller are easily worn and jamming is likely to occur. Moreover, the gas phase drives the active impeller to rotate, which increases the kinetic energy of the gas phase and leads to a significant increase in driving energy consumption. Summary of the Invention

[0006] This application proposes an electronic-grade trichloroethylene purification production apparatus and its production process, which has the advantages of low energy consumption and sufficient gas-liquid contact, thereby solving the problem that insufficient gas-liquid contact affects the purification efficiency and effect when existing distillation equipment is used to purify electronic-grade trichloroethylene.

[0007] To achieve the above objectives, this application adopts the following technical solution: an electronic-grade trichloroethylene purification production apparatus, comprising a distillation column, wherein the bottom and top of the distillation column are respectively provided with a feed outlet and a gas outlet, and the outer side of the distillation column is provided with a gas inlet, a reflux inlet and a feed inlet in sequence from bottom to top; the interior of the distillation column is fixedly provided with multiple longitudinally equidistant trays, the top of the trays is fixedly provided with several overflow frames, the bottom of the trays is fixedly provided with a guide plate located directly below the overflow frames, and the bottom of the guide plate and the overflow frames below it are reserved with a gap for liquid phase overflow; liquid guide grooves are opened on both sides of the guide plate on the trays, and gas guide pipes are fixedly provided on both sides of the guide plate at the bottom of the trays, and several gas guide grooves are opened on both sides of the gas guide pipes; the vapor flowing out through the gas guide pipes forms a cross-shaped contact mass transfer with the liquid film flowing vertically downward along the guide plate.

[0008] Furthermore, an annular baffle is provided between two adjacent trays, and the annular baffle is close to the outer edge of the tray. Two isolation blocks are fixedly installed on the outer side of the annular baffle, and the two isolation blocks are distributed in a circumferential array on the outer side of the annular baffle. The two isolation blocks divide the chamber between the two adjacent trays into a first guide chamber and a second guide chamber. The two adjacent first guide chambers and second guide chambers are staggered, and the first guide chamber is connected to the second guide chamber directly above it. The steam flowing out through the gas guide pipe enters the interior of the second guide chamber, and then enters the upper guide chamber through the first guide chamber. Inside the gas pipe, each layer of vapor can flow out from the gas guide pipe, forming a cross-shaped contact mass transfer with the liquid film flowing vertically downward from the guide plate. The cross-shaped flow generates high-frequency turbulent disturbance, causing the gas-liquid interface to continuously break and recombine, significantly shortening the mass transfer boundary layer thickness and reducing mass transfer resistance. After the liquid film is cut into a thin layer by the airflow, heat exchange is more rapid, reducing the risk of decomposition caused by local overheating. It is suitable for the distillation and purification of easily hydrolyzed materials such as trichloroethylene. Furthermore, the vertical downward flow of the liquid phase is supported laterally by the airflow, resulting in a more uniform liquid film thickness and avoiding local flooding caused by wall flow in packed towers.

[0009] Furthermore, a feed trough is provided on one of the isolation blocks, which connects the feed inlet and the inner cavity of the annular partition to ensure that the liquid phase can be added into the inner cavity of the annular partition through the feed inlet.

[0010] Furthermore, the annular partition has an outlet groove connecting the first flow guide chamber and the inner cavity of the annular partition, and the outlet groove is close to the top of the annular partition. The annular partition also has an inlet groove connecting the second flow guide chamber and the inner cavity of the annular partition, and the inlet groove is located in the middle of the annular partition. Several ventilation grooves are formed on one outer edge of the tower plate. The first flow guide chamber is connected to the second flow guide chamber directly below it through the ventilation groove, so that the steam enters the interior of the first flow guide chamber through the ventilation groove, enters the inner cavity of the annular partition through the outlet groove, enters the interior of the second flow guide chamber through the inlet groove, and then enters the first flow guide chamber directly above the second flow guide chamber through the ventilation groove. This forms a stable unidirectional flow channel for the steam, allowing the steam to flow out through the ventilation groove on one of the ventilation pipes and then flow into the ventilation pipe above.

[0011] Furthermore, guide blocks are fixedly connected to the bottom of both sides of the guide plate. The top of the guide block on the side away from the guide plate is designed with a slope, and the outer distance between the two guide blocks is greater than the width of the overflow frame. Through the guidance of the guide blocks on both sides of the guide plate, it is ensured that the liquid phase will not fall directly into the overflow frame, but will overflow into the overflow frame on the tray and then flow downward from the liquid guide groove in the overflow frame.

[0012] Furthermore, the surface of the guide plate is provided with several equally spaced guide grooves, which can be vertical grooves, inclined grooves, or S-shaped grooves, so that when the liquid phase flows down along the guide groove, it can form a more stable "liquid curtain" instead of directly falling as large water droplets, thereby ensuring that the flowing liquid phase can come into more full contact with the steam.

[0013] A production process for an electronic-grade trichloroethylene purification production apparatus, wherein the production process of the electronic-grade trichloroethylene purification apparatus is as follows:

[0014] S1. Raw material pretreatment: deacidification and dehydration

[0015] After filtering out solid particulate impurities, the industrial-grade trichloroethylene raw material is passed into an alkaline washing and neutralization tower. The alkaline solution is used to wash away free chlorine and acidic impurities (HCl). The pH of the effluent is controlled at 6-8. The neutralized material enters a molecular sieve drying tower for adsorption and dehydration until the moisture content of the material is ≤20ppm.

[0016] S2, Precision Continuous Distillation:

[0017] Two distillation columns are set up for distillation. The pretreated dried material enters the interior of one distillation column for light-weight removal, with an operating pressure of 0.07~-0.08 MPa and a temperature of 55~70℃, separating low-boiling-point impurities such as dichloromethane and vinyl chloride. The liquid phase after light-weight removal then enters the other distillation column for heavy-weight removal, with an operating pressure of -0.07~-0.08 MPa and a bottom temperature of 70–85℃, separating high-boiling-point impurities such as tetrachloroethylene and 1,1,1-trichloroethane. During the separation process, the rising vapor from the bottom of the column enters the distillation column and forms a cross-shaped mass transfer with the liquid film flowing vertically downward along the guide plate.

[0018] S3, Deep Purification Coupling:

[0019] The crude product from distillation flows through a purification tower packed with large-pore, weakly acidic chelating resin, operating at 20-30°C and atmospheric pressure. It selectively adsorbs metal ions such as Fe, Cu, Al, and Na, reducing the content of single metal impurities to ≤1 ppb. The resin-treated liquid then enters an activated carbon or modified silica gel adsorption tower to remove residual organic matter and color. Further dehydration is carried out using hydrophobic membrane modules, combined with a low-temperature condensation process, to ensure that the final moisture content is stable at ≤10 ppm.

[0020] S4. Ultra-clean filtration and filling:

[0021] The purified liquid is driven by a slight positive pressure and passes through a PTFE / PTFE terminal filter with a precision of 0.01μm to remove particulate matter (ensuring that ≥0.1μm particles ≤10 particles / mL). The filtered electronic-grade TCE enters the ultra-clean receiving tank and is filled in a Class 100 clean environment using nitrogen protection in a fully sealed manner. The packaging material is a dedicated clean container made of PFA or HDPE.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This application provides an electronic-grade trichloroethylene purification production apparatus and its production process. By setting several guide plates at the bottom of the tray and setting gas guide pipes on both sides of the guide plates, steam flows out from the gas guide grooves on both sides of the gas guide pipes and forms a cross-shaped contact mass transfer with the liquid film flowing vertically down along the guide plates. This static structure uses the cross-shaped flow to generate high-frequency turbulent disturbance, causing the gas-liquid interface to continuously break and recombine, significantly shortening the mass transfer boundary layer thickness, reducing mass transfer resistance, and making heat exchange more rapid after the liquid film is cut into a thin layer by the airflow, reducing the risk of decomposition caused by local overheating. It is suitable for high-efficiency distillation purification of trichloroethylene.

[0024] 2. The electronic-grade trichloroethylene purification production apparatus and its production process provided in this application enable each layer of steam to flow out from the gas guide pipe and form a cross-shaped contact mass transfer with the liquid film flowing vertically downward from the guide plate. This allows the vertical downward flow of the liquid phase to be laterally supported by the airflow, resulting in a more uniform liquid film thickness. This avoids the local flooding problem caused by wall flow that is common in existing distillation columns, further improving the purification effect and efficiency of trichloroethylene. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort:

[0026] Figure 1 This is a schematic diagram of the distillation column of the present invention;

[0027] Figure 2 for Figure 1 A schematic diagram of part of the tray structure inside a medium-distillation column;

[0028] Figure 3 for Figure 2 The front view;

[0029] Figure 4 for Figure 3 A schematic diagram of the middle section structure;

[0030] Figure 5 for Figure 3 A schematic diagram of the cross-sectional structure at point aa;

[0031] Figure 6 for Figure 2 A schematic diagram of the structure of one of the trays in the diagram;

[0032] Figure 7 for Figure 6 The right view;

[0033] Figure 8 for Figure 6 Top view;

[0034] Figure 9 for Figure 8 A magnified schematic diagram of the structure at point A;

[0035] Figure 10 This is a schematic diagram of the structure of one of the guide plates in Embodiment 2.

[0036] In the diagram: 1. Distillation column; 101. Feed outlet; 102. Gas outlet; 103. Gas inlet; 104. Reflux outlet; 105. Feed inlet; 2. Tray; 201. Ventilation trough; 202. Liquid guide trough; 3. Annular baffle; 301. Gas outlet trough; 302. Gas inlet trough; 4. Isolation block; 401. Feed trough; 5. First guide chamber; 6. Second guide chamber; 7. Overflow frame; 8. Guide plate; 801. Guide trough; 9. Gas guide pipe; 901. Gas guide trough; 10. Guide block. Detailed Implementation

[0037] 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.

[0038] Example 1

[0039] like Figure 1 An electronic-grade trichloroethylene purification production apparatus includes a distillation column 1. The distillation column 1 has a discharge port 101 at the center of its bottom end, a gas outlet 102 at the center of its top end, a gas inlet 103 at the bottom of its outer side, a reflux port 104 at the top of its outer side, and a feed inlet 105 located between the gas inlet 103 and the reflux port 104 on its outer side. The feed inlet 105 is positioned outside the distillation column 1, not exceeding the center of the column. The mixture is drawn from... The feed enters the distillation column 1 through the feed inlet 105 and undergoes fractionation and purification inside the distillation column 1. The vapor enters the distillation column 1 through the gas inlet 103 and flows upward inside the distillation column 1 before being discharged through the gas outlet 102. The reflux liquid enters through the reflux outlet 104. The gas phase and the liquid phase are in full contact inside the distillation column 1, achieving directional separation or chemical reaction of the components. That is, through the mass transfer process at the two-phase interface, the target substance is transferred from one phase to another, thereby achieving the purpose of purification, recovery or synthesis.

[0040] like Figures 2-7The distillation column 1 has several longitudinally equidistant trays 2 fixedly arranged inside. An annular partition 3 is positioned between adjacent trays 2, close to the outer edge of the tray 2. Two isolation blocks 4 are fixedly arranged on the outer side of the annular partition 3, arranged in a circumferential array. The tops and bottoms of the two isolation blocks 4 are sealed to the two trays 2 respectively, thus dividing the cavity between adjacent trays 2 into a first flow guide chamber 5 and a second flow guide chamber 6, which are vertically adjacent. The two first guide chambers 5 and the second guide chamber 6 are staggered. That is, when the lowest first guide chamber 5 is located on the left side of the isolation block 4 and the second guide chamber 6 is located on the right side of the isolation block 4, the first guide chamber 5 above it is located on the right side of the isolation block 4 and the second guide chamber 6 is located on the left side of the isolation block 4. The next higher first guide chamber 5 is located on the left side of the isolation block 4 and the second guide chamber 6 is located on the right side of the isolation block 4. This staggered arrangement is also provided on one of the isolation blocks 4. The feed trough 401 is connected to the feed inlet 105 and the inner cavity of the annular partition 3.

[0041] An annular partition 3 has an outlet groove 301 that connects the first guide chamber 5 and the inner cavity of the annular partition 3, and the outlet groove 301 is close to the top of the annular partition 3. An inlet groove 302 that connects the second guide chamber 6 and the inner cavity of the annular partition 3 is also provided on the annular partition 3, and the inlet groove 302 is located in the middle of the annular partition 3. Several ventilation grooves 201 are provided on the outer edge of one side of the tower plate 2. The first guide chamber 5 is connected to the second guide chamber 6 directly below it through the ventilation grooves 201, so that steam enters the interior of the first guide chamber 5 through the ventilation grooves 201, enters the inner cavity of the annular partition 3 through the outlet grooves 301, enters the interior of the second guide chamber 6 through the inlet grooves 302, and then enters the first guide chamber 5 directly above the second guide chamber 6 through the ventilation grooves 201.

[0042] Several overflow frames 7 are fixedly installed on the top of the tray 2, located inside the annular baffle 3. There are at least two overflow frames 7, and these overflow frames 7 are arranged equidistantly on the top of the tray 2. Figures 8-9 A guide plate 8 is fixedly installed at the bottom of the tray 2, located directly below the overflow frame 7, and a gap is reserved between the bottom of the guide plate 8 and the overflow frame 7 below it for liquid phase overflow. Figure 8 Figure 9 The tray 2 has two liquid guide grooves 202 located in the cavity of the overflow frame 7, and the two liquid guide grooves 202 are respectively located on both sides of the guide plate 8. The liquid phase on the tray 2 overflows into the interior of the overflow frame 7, and flows downward along both sides of the guide plate 8 through the liquid guide grooves 202.

[0043] Please continue reading. Figures 2-7The bottom of the tray 2 is fixedly provided with gas guide pipes 9 located on both sides of the guide plate 8, and the inner cavity of the gas guide pipe 9 is connected to the gas outlet groove 301. Several gas guide grooves 901 are opened on both sides of the gas guide pipe 9. The steam entering the inner cavity of the gas guide pipe 9 through the gas outlet groove 301 flows out from the gas guide groove 901 toward the surface of the guide plate 8 and fully contacts the liquid phase flowing down along the surface of the guide plate 8. The steam flows through the air inlet groove 302 on one side of the annular partition 3 into the second guide chamber 6, and flows from the ventilation groove 201 to the first guide chamber 5 directly above the second guide chamber 6. The liquid phase falls down along the guide plate 8 onto a tray 2 below, and overflows from the tray 2 into the interior of the overflow frame 7 and continues to flow downward. In this way, gas-liquid mixing and contact are carried out layer by layer.

[0044] Guide blocks 10 are fixedly connected to the bottom of both sides of the guide plate 8. The top of the guide block 10 on the side away from the guide plate 8 is designed with a slope, and the outer distance between the two guide blocks 10 is greater than the width of the overflow frame 7. Through the guidance of the guide blocks 10 on both sides of the guide plate 8, it is ensured that the liquid phase will not fall directly into the overflow frame 7, but will overflow from the tray 2 into the overflow frame 7, and then flow downward from the liquid guide groove 202 in the overflow frame 7.

[0045] The production process of the electronic-grade trichloroethylene purification production unit is as follows:

[0046] S1. Raw material pretreatment: deacidification and dehydration

[0047] After filtering out solid particulate impurities, the industrial-grade trichloroethylene raw material is passed into an alkaline washing and neutralization tower. The alkaline solution is used to wash away free chlorine and acidic impurities (HCl). The pH of the effluent is controlled at 6-8. The neutralized material enters a molecular sieve drying tower for adsorption and dehydration until the moisture content of the material is ≤20ppm.

[0048] S2, Precision Continuous Distillation:

[0049] Two distillation columns 1 are connected in series for distillation. The pretreated dried material enters one of the distillation columns 1 for light-weight impurity removal at an operating pressure of 0.07 to -0.08 MPa and a temperature of 55 to 70°C to separate low-boiling-point impurities such as dichloromethane and vinyl chloride. The liquid phase after light-weight removal then enters the other distillation column 1 for heavy-weight impurity removal at an operating pressure of -0.07 to -0.08 MPa and a bottom temperature of 70–85°C to separate high-boiling-point impurities such as tetrachloroethylene and 1,1,1-trichloroethane. During the separation process, the rising vapor from the bottom of the column enters the distillation column 1 and forms a cross-shaped mass transfer with the liquid film flowing vertically downward along the guide plate 8.

[0050] S3, Deep Purification Coupling:

[0051] The crude product from distillation flows through a purification tower packed with large-pore, weakly acidic chelating resin, operating at 20-30°C and atmospheric pressure. It selectively adsorbs metal ions such as Fe, Cu, Al, and Na, reducing the content of single metal impurities to ≤1 ppb. The resin-treated liquid then enters an activated carbon or modified silica gel adsorption tower to remove residual organic matter and color. Further dehydration is carried out using hydrophobic membrane modules, combined with a low-temperature condensation process, to ensure that the final moisture content is stable at ≤10 ppm.

[0052] S4. Ultra-clean filtration and filling:

[0053] The purified liquid is driven by a slight positive pressure and passes through a PTFE / PTFE terminal filter with a precision of 0.01μm to remove particulate matter (ensuring that ≥0.1μm particles ≤10 particles / mL). The filtered electronic-grade TCE enters the ultra-clean receiving tank and is filled in a Class 100 clean environment using nitrogen protection in a fully sealed manner. The packaging material is a dedicated clean container made of PFA or HDPE.

[0054] Example 2

[0055] like Figure 10 Based on Embodiment 1, the difference is that the surface of the guide plate 8 is provided with a guide groove 801 so that when the liquid phase flows down along the guide groove 801, it can form a more stable "liquid curtain" instead of directly falling as large water droplets, thereby ensuring that the flowing liquid phase can come into more full contact with the steam.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A purification and production apparatus for electronic-grade trichloroethylene, comprising a distillation column, wherein the bottom and top of the distillation column are respectively provided with a feed outlet and a gas outlet, and the outer side of the distillation column is provided with a gas inlet, a reflux inlet and a feed inlet sequentially from bottom to top; and the interior of the distillation column is fixedly provided with a plurality of longitudinally equidistant trays, characterized in that, Several overflow frames are fixedly installed on the top of the tray, and a guide plate is fixedly installed at the bottom of the tray directly below the overflow frames. A gap is reserved between the bottom of the guide plate and the overflow frames below it for liquid overflow. Liquid guide grooves are opened on both sides of the guide plate on the tray. Gas guide pipes are fixedly installed on both sides of the guide plate at the bottom of the tray. Several gas guide grooves are opened on both sides of the gas guide pipes. The vapor flowing out through the gas guide pipes forms a cross-shaped contact mass transfer with the liquid film flowing vertically down along the guide plate.

2. The electronic-grade trichloroethylene purification and production apparatus according to claim 1, characterized in that, An annular baffle is provided between two adjacent trays, and the annular baffle is close to the outer edge of the tray. Two isolation blocks are fixedly provided on the outer side of the annular baffle. The two isolation blocks are distributed in a circumferential array on the outer side of the annular baffle. The two isolation blocks divide the chamber between the two adjacent trays into a first flow guide chamber and a second flow guide chamber. The two adjacent first flow guide chambers and second flow guide chambers are staggered. The first flow guide chamber is connected to the second flow guide chamber directly above it. The steam flowing out through the gas guide pipe enters the interior of the second flow guide chamber, and then enters the gas guide pipe above through the first flow guide chamber.

3. The electronic-grade trichloroethylene purification and production apparatus according to claim 2, characterized in that, One of the isolation blocks has a feed chute, which connects the feed inlet and the inner cavity of the annular partition.

4. The electronic-grade trichloroethylene purification and production apparatus according to claim 2, characterized in that, The annular partition plate has an outlet groove that connects the first flow guide chamber and the inner cavity of the annular partition plate, and the outlet groove is close to the top of the annular partition plate. The annular partition plate has an inlet groove that connects the second flow guide chamber and the inner cavity of the annular partition plate, and the inlet groove is located in the middle of the annular partition plate. Several ventilation grooves are provided on one outer edge of the tower plate.

5. The electronic-grade trichloroethylene purification and production apparatus according to claim 1, characterized in that, The bottom of each side of the guide plate is fixedly connected to a guide block. The top of the guide block on the side away from the guide plate is designed with a slope, and the outer distance between the two guide blocks is greater than the width of the overflow frame.

6. The electronic-grade trichloroethylene purification and production apparatus according to claim 1, characterized in that, The surface of the guide plate is provided with several equally spaced guide grooves.

7. A production process for an electronic-grade trichloroethylene purification production apparatus, characterized in that, The production process of the electronic-grade trichloroethylene purification production unit is as follows: S1. Raw material pretreatment: deacidification and dehydration After filtering out solid particulate impurities, the industrial-grade trichloroethylene raw material is passed into an alkaline washing and neutralization tower. The alkaline solution is used to wash away free chlorine and acidic impurities (HCl). The pH value of the effluent is controlled at 6-8. The neutralized material enters a molecular sieve drying tower for adsorption and dehydration until the moisture content of the material is ≤20ppm. S2, Precision Continuous Distillation: Two distillation columns are set up for distillation. The pretreated dried material enters the interior of one distillation column for light-weight removal. The operating pressure is 0.07~-0.08 MPa and the temperature is 55~70℃ to separate low-boiling-point impurities such as dichloromethane and vinyl chloride. The liquid phase after light-weight removal then enters the other distillation column for heavy-weight removal. The operating pressure is -0.07~-0.08 MPa and the bottom temperature is 70–85℃ to separate high-boiling-point impurities such as tetrachloroethylene and 1,1,1-trichloroethane. During the separation process, the rising vapor from the bottom of the column enters the distillation column and forms a cross-shaped mass transfer with the liquid film flowing vertically downward along the guide plate. S3, Deep Purification Coupling: The crude product from distillation flows through a purification tower packed with large-pore, weakly acidic chelating resin, operating at 20-30°C and atmospheric pressure. It selectively adsorbs metal ions such as Fe, Cu, Al, and Na, reducing the content of single metal impurities to ≤1 ppb. The resin-treated liquid then enters an activated carbon or modified silica gel adsorption tower to remove residual organic matter and color. Further dehydration is carried out using a hydrophobic membrane module, combined with a low-temperature condensation process, to ensure that the final moisture content is stable at ≤10 ppm. S4. Ultra-clean filtration and filling: The purified liquid is driven by a slight positive pressure and passes through a PTFE / PTFE terminal filter with a precision of 0.01μm to remove particulate matter (ensuring that ≥0.1μm particles ≤10 particles / mL). The filtered electronic-grade TCE enters the ultra-clean receiving tank and is filled in a fully sealed manner under nitrogen protection in a Class 100 clean environment. The packaging material is a dedicated clean container made of PFA or HDPE.

Images