A method and device for preparing ultrapure isopropyl alcohol

Abstract

The present application relates to a method and apparatus for preparing ultrapure isopropyl alcohol. The method comprises the following steps: feeding SEMI-G3 grade isopropyl alcohol into a vaporizing device through a raw material conveying device to obtain vaporized isopropyl alcohol; treating the vaporized isopropyl alcohol through a vapor-liquid separation device, and then conveying the vaporized isopropyl alcohol to a separation membrane assembly for treatment to obtain an isopropyl alcohol solution, wherein the separation membrane assembly has undergone a pretreatment to reduce dissolution; treating the isopropyl alcohol solution through an ion exchange resin to obtain the ultrapure isopropyl alcohol, wherein the ultrapure isopropyl alcohol has a single ion content of between 1 and 10 ppt and a water content of less than 10 ppm. The preparation process of the ultrapure isopropyl alcohol in the present application is simple, can reduce the preparation cost of ultrapure isopropyl alcohol, and reduce the generation of solid waste.

Description

Technical Field

[0001] The present application belongs to the technical field of isopropyl alcohol preparation, and specifically relates to a method and apparatus for preparing ultrapure isopropyl alcohol. Background Art

[0002] Ultrapure reagents, also known as wet chemicals or process chemicals, are currently widely used in a variety of fields, including semiconductors, flat panel displays, and solar cells. Among these, wet electronic chemicals used in solar panel manufacturing have the lowest requirements, while flat panel display manufacturing has the highest demand. Semiconductor manufacturing processes have the highest technical requirements. The purity and cleanliness of wet electronic chemicals have a significant impact on the yield, electrical performance, and reliability of integrated circuits (ICs). Water and metal ion content, in particular, can oxidize silicon wafers, creating defects, while metal ions can cause internal short circuits within ICs, impacting product yield. At present, the international SEMI standardization organization divides ultrapure reagents into five grades according to their application scope: SEMI-G1 standard (applicable to the production of IC process technology >1.2μm), SEMI-G2 standard (applicable to the production of IC process technology 0.8~1.2μm), SEMI-G3 standard (applicable to the production of IC process technology 0.2~0.60μm), SEMI-G4 standard (applicable to the production of IC process technology 0.09~0.20μm, with water content less than 50ppm and ion content less than 100ppt), SEMI-G5 standard (applicable to the production of IC process technology <0.09μm, with water content less than 20ppm and ion content less than 10ppt). Among them, ultrapure solvents of SEMI-G1-G3 grades are basically domestically produced, while G4 and G5 grade solvents all need to be imported.

[0003] Isopropyl alcohol (IPA) is a widely used basic chemical. Ultra-pure IPA, as a key microelectronics chemical, is widely used in cleaning and drying processes in semiconductor and large-scale integrated circuit manufacturing. Its purity and cleanliness significantly impact the yield, electrical performance, and reliability of integrated circuit products. Currently, ultra-pure IPA is typically refined from industrial-grade IPA. For example, one related technique uses industrial-grade reagents as raw materials. After chemical pretreatment and filtration, the resulting filtrate undergoes distillation. During the distillation process, the steam is heated to form superheated steam, which is then filtered through an air membrane to remove impurities and solid particles. The steam is then cooled and filtered through a secondary membrane to remove dust particles, resulting in high-purity IPA. However, this process requires multiple vapor-liquid exchange cycles and is energy-intensive. Alternatively, a high-purity product is obtained using carbonates to adjust the pH, followed by the addition of activated carbon, anhydrous calcium chloride, and calcium hydroxide for water removal, followed by filtration, distillation, and resin exchange. This method generates significant amounts of solid and hazardous waste. Overall, the current production of ultrapure isopropyl alcohol presents environmentally harmful solid waste, high energy consumption for distillation, extensive ion exchange resin replacement, and intermittent operation. Therefore, reducing the production cost of ultrapure isopropyl alcohol and reducing solid waste generation are urgent issues that the industry needs to address. Summary of the Invention

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a method for preparing ultrapure isopropyl alcohol, which can effectively save energy consumption and improve the simplicity of the operation process while reducing the generation of solid waste.

[0005] According to a first aspect of the present application, a method for preparing ultrapure isopropyl alcohol is provided, comprising the following steps:

[0006] The SEMI-G3 grade isopropyl alcohol is fed into a vaporization device through a raw material conveying device to obtain vaporized isopropyl alcohol;

[0007] The vaporized isopropyl alcohol is processed through a vapor-liquid separation device and then transported to a separation membrane assembly for treatment to obtain an isopropyl alcohol solution, wherein the separation membrane assembly has undergone a dissolution reduction pretreatment;

[0008] The isopropyl alcohol solution is treated with an ion exchange resin to obtain the ultrapure isopropyl alcohol, wherein the ultrapure isopropyl alcohol has a single ion content of 1-10 ppt and a water content of less than 10 ppm.

[0009] The method for preparing ultra-pure isopropyl alcohol according to the embodiment of the present application has at least the following beneficial effects: SEMI-G3 grade isopropyl alcohol is first vaporized, then separated, and transported to a separation membrane assembly that has been pretreated to reduce dissolution for treatment, and then ion exchange is performed through an ion exchange resin. The preparation process is simple, can reduce the preparation cost of ultra-pure isopropyl alcohol, and can reduce the generation of solid waste.

[0010] It is worth noting that the dehydration process used in the relevant technology will go through the distillation process, molecular sieve adsorption or chemical desiccant, among which distillation dehydration is a high energy consumption process. The dehydration limit of domestic distillation towers is about 500ppm. Further reducing the water content will increase the energy consumption exponentially. In order to obtain products with a water content of <500ppm, it is necessary to couple zeolite molecular sieves or chemical adsorbents. The drying of molecular sieves or chemical reagents will cause a large amount of ions to dissolve, and the dissolution is usually above 10ppm, which will increase the load of subsequent ion exchange resins. The ion exchange resins used in G4 or G5 grades are currently disposable and expensive. If the frequency of ion exchange resin replacement can be reduced, it can effectively reduce the generation of solid waste and reduce the preparation cost of ultra-clean high-purity solvents. Compared with molecular sieve particles and chemical adsorption, the amount of molecular sieve on the surface of the molecular sieve membrane is extremely low. The weight of the molecular sieve layer on the surface of the molecular sieve membrane is 10g / m 2 For example, for a 10,000-ton dehydration project, the amount of molecular sieve membrane used is about 1000m 2 , relatively, molecular sieve or chemical adsorbent requires a dosage of about 100t. If the molecular sieve dissolution ratio is the same, the dissolution using molecular sieve membrane is only one ten-thousandth of that of adsorbent, indicating that the use of molecular sieve membrane has great advantages in controlling ion dissolution. Therefore, in order to further reduce the dissolution of molecular sieve membrane, the present application adopts pretreatment to reduce the dissolution of molecular sieve membrane, and obtains a molecular sieve membrane unit with low dissolution. In addition, since ion exchange resin has saturated adsorption capacity, if the ion content in the front-stage material is high, the ion exchange resin is easily adsorbed and saturated, and needs high-frequency replacement. The resin of G4 or G5 grade is disposable and cannot be regenerated. This disposable resin is usually treated as solid waste, so reducing the ion content of the front-stage material can effectively reduce the generation of solid waste.

[0011] It should be noted that the SEMI-G3, SEMI-G4, and SEMI-G5 grade isopropyl alcohol mentioned in this application refer to isopropyl alcohol that meets the following conditions.

[0012]

[0013] According to some embodiments of the present application, the dissolution reduction pretreatment comprises the following steps:

[0014] The separation membrane assembly is placed in an organic solvent for surface cleaning, and then the organic matter and ions on the surface of the separation membrane assembly are washed with ultra-clean deionized water. In a Class 1000 clean room, the water on the surface of the separation membrane assembly is blown away with N2 having a volume fraction greater than 99.9999% for standby use.

[0015] It is understandable that in the preparation process of ultrapure isopropyl alcohol, there will be a large amount of alkali and silicon aluminum on the surface of the separation membrane component product. In addition, there is Na + Balanced charge, in actual use due to Na + The ion valence is low and it is easy to dissolve freely. In addition, there is a membrane component that can accommodate Na + The Na+ may also be dissolved into the product, causing the ion content to exceed the standard. In response to the above two dissolution problems, the inventors of this application first cleaned the separation membrane assembly to reduce the ion dissolution during use.

[0016]

[0017] It should be noted that the ultra-clean deionized water used in the embodiments of the present application refers to deionized water that meets the following conditions:

[0018] According to some embodiments of the present application, the dissolution reduction pretreatment comprises the following steps:

[0019] The separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, and then the organic matter and ions on the surface of the separation membrane assembly after ion exchange are washed with ultra-clean deionized water. In a Class 1000 clean room, the water on the surface of the separation membrane assembly is blown away with N2 with a volume fraction greater than 99.9999% for standby use.

[0020] It is understandable that placing the separation membrane assembly in an inorganic salt solution for ion exchange treatment and replacing active sodium ions with ions having removal inertness can significantly reduce ion dissolution during use.

[0021] According to some embodiments of the present application, the dissolution reduction pretreatment comprises the following steps:

[0022] The separation membrane assembly is placed in an organic solvent for surface cleaning, and then the organic matter and ions on the surface of the separation membrane assembly are washed with ultra-clean deionized water. In a Class 1000 clean room, the water on the surface of the separation membrane assembly is blown away with nitrogen having a volume fraction greater than 99.9999% for standby use;

[0023] The above-mentioned spare separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, and then the organic matter and ions on the surface of the separation membrane assembly after ion exchange are washed with ultra-clean deionized water. In a Class 1000 clean room, N2 with a volume fraction greater than 99.9999% is used to blow away the water on the surface of the separation membrane assembly to obtain the separation membrane assembly that has undergone dissolution reduction pretreatment.

[0024] It is understandable that first cleaning the separation membrane assembly with an organic solvent and then performing ion exchange with an inorganic salt solution can further reduce ion dissolution during the dehydration process.

[0025] According to some embodiments of the present application, the organic solvent includes one or more of ethanol, isopropanol, n-propanol, acetone and / or tetrahydrofuran.

[0026] It is understandable that at room temperature, separation membranes, such as molecular sieve membranes, are relatively stable in water. However, at high temperatures, since molecular sieve membranes are easily degraded in aqueous solutions, ion exchange needs to be carried out in organic solvents. Different organic solvents have different polarity, stability, solubility and volatility. The use of the above-mentioned organic solvents can have a positive effect on subsequent ion exchange.

[0027] According to some embodiments of the present application, the cleaning comprises:

[0028] Under bubbling conditions, the organic solvent containing the separation membrane assembly is heated to 30-100° C. and treated for 1-6 hours, and the treatment process is repeated 1-5 times.

[0029] It is understandable that cleaning can remove residual organic solvents and ions on the surface, so as to avoid the introduction of a large amount of impurities during the membrane separation process due to ion exchange.

[0030] According to some embodiments of the present application, the inorganic salt solution comprises an inorganic salt solute and a solvent, wherein the inorganic salt solute comprises one or more of lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, strontium nitrate, barium hydroxide, magnesium acetate, calcium acetate, copper nitrate and / or ferric chloride, and the solvent comprises one or more of methanol, ethanol, n-propanol, isopropanol, acetone and / or tetrahydrofuran.

[0031] It's understandable that high-valent metals generally have lower mobility, while low-valent metal ions have higher mobility. Furthermore, high-valent ions are more readily absorbed by ion exchange resins than low-valent ions. Therefore, replacing low-valent ions with high-valent ions can improve ion stability in the molecular sieve membrane and reduce metal ion dissolution. Furthermore, even if high-valent ions are dissolved, they are more easily adsorbed and removed by the ion exchange resin.

[0032] According to some embodiments of the present application, the ion exchange comprises:

[0033] The inorganic salt solution containing the separation membrane assembly is bubbled and heated to 30-100° C., and treated for 1-6 hours, and the treatment process is repeated 1-6 times.

[0034] It is understood that, generally, the higher the temperature, the longer the time, and the more times, the higher the ion exchange degree. To reduce costs, this application chooses to adopt a combination of the above temperature, time, and number ranges.

[0035] According to some embodiments of the present application, the separation membrane component includes a molecular sieve zeolite membrane.

[0036] According to a first aspect of the present application, there is provided a device for preparing ultrapure isopropyl alcohol, the device comprising:

[0037] A vaporizer, used to vaporize the delivered SEMI-G3 grade isopropyl alcohol raw material;

[0038] a gas-liquid separation device, connected to the vaporization device, for separating the vaporized isopropyl alcohol;

[0039] The separation membrane component that has undergone dissolution reduction pretreatment is connected to the output end of the gas-liquid separation device to perform steam permeation dehydration treatment on the separated isopropyl alcohol;

[0040] The ion exchange resin device is used to perform ion exchange on the isopropyl alcohol solution obtained through the steam permeation dehydration treatment to obtain the ultra-pure isopropyl alcohol.

[0041] It is understood that the preparation apparatus of the present application has a simple preparation process, can reduce the production cost of ultra-pure isopropyl alcohol, and reduce solid waste generation. The processing temperature and pressure of the steam osmotic dehydration process can be consistent with the temperature and pressure of the vaporization device and the gas-liquid separation device. For example, the processing temperature of the steam osmotic dehydration process is between 90-150°C and the pressure is between 100-600kPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0043] Figure 1 Schematic diagram of the method and apparatus for preparing ultrapure isopropyl alcohol in one embodiment of the present application.

[0044] The features corresponding to the reference numerals are as follows:

[0045] 1. Vaporizer; 2. Gas-liquid separator; 3. Separation membrane assembly; 4. Ion exchange resin. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the concept and technical effects of this application in conjunction with the embodiments to fully understand the purpose, features and effects of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of this application.

[0047] In the description of this application, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0048] The following is combined with Figure 1 Detailed description of the specific embodiments of the present application.

[0049] Example 1

[0050] Effect of ethanol cleaning on ion dissolution from zeolite membrane

[0051] Pretreatment of zeolite membrane to reduce dissolution: First, place the zeolite membrane in ethanol to clean the surface. Under bubbling conditions, heat it to 50°C and treat it for 2 hours. Repeat this process 3 times. After cleaning, use ultra-clean high-purity deionized water at 20°C to wash away organic matter and ions on the surface. In a Class 1000 clean room, use N2 with a volume fraction of 99.99999% at 30°C to blow away the water on the surface of the zeolite membrane for use.

[0052] The pre-treated zeolite membrane was loaded into the assembly and placed into the ultrapure solvent preparation device. SEMI-G3 grade isopropyl alcohol was fed into the vaporizer 1 (see attached) via a raw material pump (feed rate 200 L / h). Figure 1 ) (temperature 120C, pressure 3.8bar), IPA vaporizes and passes through gas-liquid separator 2 to separation membrane module 3 (32m 2 ), and then subjected to steam permeation dehydration to obtain an isopropanol solution with a water content of 7 ppm. The ion content of the solution was measured by ICP-MS, and the results are shown in Table 1. The IPA solution was then passed through ion exchange resin 4 to obtain an ultrapure solvent with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0053] Experimental results:

[0054] Table 1 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0055]

[0056]

[0057] Table 1 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na and Fe ions, with the Na ion content reaching approximately 100.8 ppb and the Fe ion content increasing to 10.5 ppb. This indicates that, while the zeolite membrane dehydration process increases the ion content, the zeolite membrane-related ion dissolution is below 100 ppb, and the dissolution of stainless steel-related ions (such as Fe, Cr, and Ni) is below 10 ppb. Ultimately, through ion exchange with the resin, the ion content of each ion was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0058] Therefore, dehydration of molecular sieve zeolite membrane can reduce the water content to 10ppm, and ethanol cleaning can reduce the dissolution of zeolite membrane ions, extend the service life of ion exchange resin, and finally obtain G5 grade ultra-clean high-purity reagents.

[0059] Example 2

[0060] Effect of Isopropyl Alcohol Cleaning on Ion Dissolution from Zeolite Membranes

[0061] Pretreatment of zeolite membrane to reduce dissolution: First, place the zeolite membrane in isopropyl alcohol detergent to clean the surface. Under bubbling conditions, heat it to 70°C and treat it for 6 hours. Repeat this process 5 times. After cleaning, use ultra-clean deionized water at 20°C to wash away organic matter and ions on the surface. In a Class 1000 clean room, use N2 with a volume fraction of 99.99999% at 30°C to blow away the water on the surface of the zeolite membrane for use.

[0062] The pre-treated zeolite membrane was loaded into the assembly and placed into the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into vaporizer 1 (temperature 130°C, pressure 5.2 bar) through a raw material pump (feed rate 600 L / h). After vaporization, IPA passed through gas-liquid separator 2 to separation membrane assembly 3 (150 m 2 ), and then subjected to steam permeation dehydration to obtain an IPA solution with a water content of 10 ppm. The ion content of the solution was tested by ICP-MS, and the results are shown in Table 2. The IPA solution was then passed through ion exchange resin 4 to obtain an ultra-clean, high-purity solvent with a single ion content of 7 ppt and a water content of less than 10 ppm.

[0063] Experimental results:

[0064] Table 2 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0065]

[0066] Table 2 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na and Fe ions. The Na ion content reached approximately 23.12 ppb, while the Fe ion content increased to 10.5 ppb. This indicates that, despite the increase in the content of some ions using the zeolite membrane dehydration process, the dissolution of zeolite-related ions remained below 30 ppb, and that of stainless steel-related ions was below 10 ppb. Furthermore, the content of some Mg, K, and Ca ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with ion resins, the content of all ions was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0067] Therefore, membrane dehydration can reduce the water content to 10ppm, and isopropyl alcohol cleaning can further reduce the dissolution of zeolite membrane ions, extend the service life of ion exchange resin, and ultimately obtain G5 grade ultra-clean high-purity reagents.

[0068] Example 3

[0069] Effect of acetone cleaning on ion dissolution from zeolite membrane

[0070] Pretreatment of zeolite membrane to reduce dissolution: First, place the zeolite membrane in acetone detergent to clean the surface. Under bubbling conditions, heat it to 80°C and treat it for 1 hour. Repeat this process twice. After cleaning, use ultra-clean deionized water at 20°C to wash away organic matter and ions on the surface. In a Class 1000 clean room, use N2 with a volume fraction of 99.99999% at 30°C to blow away the water on the surface of the zeolite membrane for use.

[0071] The above zeolite membrane was installed in the assembly and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into the vaporizer 1 (temperature 110°C, pressure 2.8 bar) through the raw material pump (feed rate 3000L / h). After the IPA was vaporized, it passed through the gas-liquid separator 2 to the separation membrane assembly 3 (900m 2 ), and steam permeation dehydration was performed to obtain an IPA solution with a water content of 5 ppm. The ion content of the solution was measured by ICP-MS, and the results are shown in Table 3. After the IPA solution was passed through ion exchange resin 4, an ultra-clean, high-purity solvent meeting the G5 grade was obtained, with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0072] Experimental results:

[0073] Table 3 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0074]

[0075] Table 3 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na and Fe ions. The Na ion content reached approximately 69.4 ppb, while the Fe ion content increased to 11.2 ppb. This indicates that, despite the increase in the content of some ions using the zeolite membrane dehydration process, the dissolution of zeolite-related ions remained below 70 ppb, and that of stainless steel-related ions was below 10 ppb. Furthermore, the content of some Mg, K, and Ca ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with ion resins, the content of all ions was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0076] Therefore, membrane dehydration can reduce the water content to 5ppm (the water content will increase slightly after ion exchange), and acetone cleaning can reduce the dissolution of zeolite membrane ions and extend the service life of ion exchange resins. By combining membrane dehydration with resin deionization process, G5 grade ultra-clean high-purity reagents can be finally obtained.

[0077] Example 4

[0078] Mg 2+ Effect of ion exchange on ion dissolution from zeolite membranes

[0079] Zeolite membrane dissolution reduction pretreatment: The pre-synthesized zeolite membrane was placed in a 0.1M magnesium acetate solution (solvent is isopropanol), and the temperature was raised to 60°C by bubbling for 6 hours, and exchanged 3 times. After ion exchange, the organic matter and ions on the surface were washed away with ultra-clean deionized water at 20°C. In a Class 1000 clean room, the water on the surface of the zeolite membrane was blown away with N2 with a volume fraction of 99.99999% at 30°C for standby use.

[0080] The pre-treated zeolite membrane was loaded into the assembly and placed into the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into vaporizer 1 (temperature 120°C, pressure 3.8 bar) through a raw material pump (feed rate 5000 L / h). After vaporization, IPA passed through gas-liquid separator 2 to separation membrane assembly 3 (1200 m 2 ), and steam permeation dehydration was performed to obtain an IPA solution with a water content of 15 ppm. The ion content of the solution was measured by ICP-MS, and the results are shown in Table 4. After the IPA solution was passed through ion exchange resin 4, an ultra-clean, high-purity solvent meeting the G5 grade was obtained, with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0081] Table 4 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0082]

[0083] Table 4 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na, Mg, and Fe. The Na ion content reached approximately 162 ppb, the Mg ion content reached approximately 166 ppb, and the Fe ion content increased to 10.5 ppb. This indicates that, while the zeolite membrane dehydration process resulted in some increases in the content of some ions, the zeolite membrane-related ion dissolution was below 330 ppb, and the stainless steel-related ion dissolution was below 10 ppb. Furthermore, the content of some calcium ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with the resin, the content of all ions was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0084] Therefore, membrane dehydration can reduce the water content to 10ppm, Mg ion exchange can reduce the ion dissolution of zeolite membrane and extend the service life of ion exchange resin. By combining membrane dehydration with resin deionization process, G5 grade ultra-clean high-purity reagents can be finally obtained.

[0085] Example 5

[0086] Sr 2+ Effect of ion exchange on ion dissolution from zeolite membranes

[0087] Zeolite membrane dissolution reduction pretreatment: The pre-synthesized zeolite membrane was placed in a 0.05M strontium acetate solution (solvent: ethanol), and the temperature was raised to 70°C by bubbling for 5 hours and exchanged 5 times. After ion exchange, the organic matter and ions on the surface were washed away with ultra-clean deionized water at 20°C. In a Class 1000 clean room, the water on the surface of the zeolite membrane was blown away with N2 with a volume fraction of 99.99999% at 30°C for standby use.

[0088] The above zeolite membrane was installed in the assembly and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into the vaporizer 1 (temperature 130°C, pressure 5.2 bar) through the raw material pump (feed rate 600L / h). After the IPA was vaporized, it passed through the gas-liquid separator 2 to the separation membrane assembly 3 (150m 2 ), and then subjected to steam permeation dehydration to obtain an IPA solution with a water content of 10 ppm. The ion content of the solution was tested by ICP-MS, and the results are shown in Table 5. The IPA solution was then passed through ion exchange resin 4 to obtain an ultra-clean, high-purity solvent with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0089] Table 5 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0090]

[0091]

[0092] Table 5 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na, Sr, and Fe. The Na ion content reached approximately 35 ppb, the Sr ion content reached approximately 10 ppb, and the Fe ion content increased to 10.5 ppb. This indicates that, despite the increase in the content of some ions using the zeolite membrane dehydration process, the dissolution of zeolite-related ions remained below 30 ppb, and that of stainless steel-related ions remained below 10 ppb. Furthermore, the content of some Mg and Ca ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with the resin, the content of all ions was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0093] Therefore, membrane dehydration can reduce the water content to 10ppm, Sr ion exchange can significantly reduce the dissolution of zeolite membrane ions, extend the service life of ion exchange resins, and ultimately obtain G5 grade ultra-clean high-purity reagents through membrane dehydration combined with resin deionization process.

[0094] Example 6

[0095] Pr 3+ Effect of ion exchange on ion dissolution from zeolite membranes

[0096] Zeolite membrane dissolution reduction pretreatment: The pre-synthesized zeolite membrane was placed in a 0.5M praseodymium nitrate solution (solvent: tetrahydrofuran), and the temperature was raised to 50°C by bubbling for 6 hours, and the ion exchange was performed 6 times. After ion exchange, the organic matter and ions on the surface were washed away with ultra-clean deionized water at 20°C. In a Class 1000 clean room, the water on the surface of the zeolite membrane was blown away with N2 with a volume fraction of 99.99999% at 30°C for standby use.

[0097] The above zeolite membrane was installed in the assembly and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into the vaporizer 1 (temperature 120°C, pressure 3.8 bar) through the raw material pump (feed rate 200L / h). After the IPA was vaporized, it passed through the gas-liquid separator 2 to the separation membrane assembly 3 (32m 2 ), and then subjected to steam permeation dehydration to obtain an IPA solution with a water content of 20 ppm. The ion content of the solution was tested by ICP-MS, and the results are shown in Table 6. The IPA solution was then passed through ion exchange resin 4 to obtain an ultra-clean, high-purity solvent with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0098] Table 6 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0099]

[0100]

[0101] Table 6 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of some ions increased, primarily Na, Pr, and Fe. The Na ion content reached approximately 35 ppb, the Pr ion content reached approximately 2.3 ppb, and the Fe ion content increased to 10.5 ppb. This indicates that, despite the increase in the content of some ions using the zeolite membrane dehydration process, the dissolution of zeolite-related ions remained below 30 ppb, and that of stainless steel-related ions was below 10 ppb. Furthermore, the content of some Mg and Ca ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with the resin, the content of all ions was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0102] Therefore, membrane dehydration can reduce the water content to 10ppm, Pr ion exchange can significantly reduce the dissolution of zeolite membrane ions, extend the service life of ion exchange resins, and ultimately obtain G5 grade ultra-clean high-purity reagents through membrane dehydration combined with resin deionization process.

[0103] Example 7

[0104] Isopropyl alcohol cleaning and Pr 3+ Effect of ion exchange on ion dissolution from zeolite membranes

[0105] Zeolite membrane dissolution reduction pretreatment: First, the zeolite membrane was placed in 50% isopropanol, 25% acetone and 25% tetrahydrofuran cleaning agent to clean the surface. Under bubbling conditions, the temperature was raised to 60°C and treated for 6 hours. The process was repeated 6 times. After cleaning, the organic matter and ions on the surface were washed away with ultra-clean deionized water at 20°C. In a Class 1000 clean room, the water on the surface of the zeolite membrane was blown away with N2 with a volume fraction of 99.99999% at 30°C for standby use.

[0106] The above-mentioned zeolite membrane was placed in a 0.1M praseodymium nitrate solution (solvent: 50% tetrahydrofuran + 50% isopropanol), and the temperature was raised to 70°C by bubbling for 6 hours and exchanged 5 times. After ion exchange, the organic matter and ions on the surface were washed away with ultra-clean deionized water at 20°C. In a Class 1000 clean room, the water on the surface of the zeolite membrane was blown away with N2 with a volume fraction of 99.99999% at 30°C for standby use.

[0107] The above zeolite membrane was installed in the assembly and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into the vaporizer 1 (temperature 120°C, pressure 3.8 bar) through the raw material pump (feed rate 5000L / h). After the IPA was vaporized, it passed through the gas-liquid separator 2 to the separation membrane assembly 3 (1800m 2 ), and steam permeation dehydration was performed to obtain an IPA solution with a water content of 5 ppm. The ion content of the solution was measured by ICP-MS, and the results are shown in Table 7. After the IPA solution was passed through ion exchange resin 4, an ultra-clean, high-purity solvent meeting the G5 grade was obtained, with a single ion content of 10 ppt and a water content of less than 10 ppm.

[0108] Table 7 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0109]

[0110] Table 7 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the content of individual ions increased slightly, primarily in Na, Pr, and Fe ions. The Na ion content reached approximately 12 ppb, the Pr ion content reached approximately 1 ppb, and the Fe ion content increased to 8.7 ppb. This indicates that, while the zeolite membrane dehydration process resulted in an increase in the content of individual ions, the zeolite membrane-related ion dissolution remained below 10 ppb, and the stainless steel-related ion dissolution remained below 10 ppb. Furthermore, the content of some Mg and Ca ions decreased after dehydration, likely due to ion exchange, as membrane dehydration facilitated the reduction of some ions. Ultimately, through ion exchange with the resin, the content of each ion was reduced to below 10 ppt, and the water content was reduced to 10 ppm, meeting the requirements for G5 ultra-clean, high-purity solvents.

[0111] Therefore, membrane dehydration can reduce the water content of a large amount of IPA to 10ppm. Zeolite membrane pre-cleaning and Pr ion exchange can significantly reduce the dissolution of zeolite membrane ions and extend the service life of ion exchange resins. Through membrane dehydration combined with resin deionization process, G5 grade ultra-clean high-purity reagents can be finally obtained.

[0112] Comparative Example 1

[0113] The problem of ion dissolution in zeolite membrane

[0114] The synthesized zeolite membrane was loaded into the assembly and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into the vaporizer 1 (temperature 120°C, pressure 3.8 bar) through the raw material pump (feed rate 200L / h). After vaporization, the IPA passed through the gas-liquid separator 2 to the separation membrane assembly 3 (50m 2), and steam permeation dehydration was performed to obtain an IPA solution with a water content of 10 ppm. The ion content of the solution was measured by ICP-MS, and the results are shown in Table 8. After the IPA solution was passed through ion exchange resin 4, an ultra-clean, high-purity solvent meeting the G4 grade was obtained, with a single ion content of 100 ppt and a water content of less than 20 ppm.

[0115] Table 8 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0116]

[0117] Table 8 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the ion content increased, with Na, K, and Ca ions showing significant increases, with Na ion content increasing to 693 ppb, K ion content to 83 ppb, and Ca ion content to 180 ppb. This indicates that using an untreated zeolite membrane for dehydration results in a total ion release of approximately 1 ppm, while the release of stainless steel-related ions is below 10 ppb. Ultimately, ion exchange with an ion resin reduced the ion content to below 100 ppt, and the water content increased to 20 ppm, only meeting the requirements for a G4-grade ultra-clean, high-purity solvent.

[0118] Therefore, membrane dehydration can reduce the water content of IPA to 10ppm (the water content will increase slightly after ion resin exchange). If the zeolite membrane is not treated, ions will be dissolved, and the dissolution amount exceeds 1ppm, which will seriously affect the service life of the ion exchange resin and the treatment efficiency of the ion resin. By combining membrane dehydration with resin deionization process, G4 grade ultra-clean high-purity reagents can be finally obtained.

[0119] Comparative Example 2

[0120] Effect of liquid phase infiltration on ion dissolution from zeolite membranes

[0121] The synthesized zeolite membrane was loaded into the module and equipped with the ultrapure solvent preparation system. SEMI-G3 grade IPA was fed into heater 1 (temperature 80°C, pressure 1 bar) through a raw material pump (feed rate 200 L / h). After being heated, IPA was fed into preheater 2 and then into separation membrane module 3 (70 m 2 ), and after liquid phase dehydration, an IPA solution with a water content of 50 ppm was obtained. The ion content of the solution was tested by ICP-MS, and the results are shown in Table 9. After the IPA solution was passed through ion exchange resin 4, an ultra-clean, high-purity solvent meeting the G3 grade was obtained, with a single ion content of 1000 ppt and a water content of less than 60 ppm.

[0122] Table 9 Raw material ion concentration, dehydrated ion concentration and product ion concentration

[0123]

[0124] Table 9 shows that the metal ion content in the raw materials was all below 10 ppb. After dehydration, the ion content increased, with significant increases in Na, K, calcium, Fe, Cr, and Ni ions. The Na ion content increased to 1156 ppb, the K ion content increased to 138 ppb, and the Ca ion content increased to 239 ppb. This indicates that the zeolite membrane liquid-phase dehydration process results in the dissolution of a large amount of ions, totaling over 2000 ppb. Stainless steel-related ions dissolve over 500 ppb, and the total stainless steel-related ions also exceed 1000 ppm. Ultimately, ion exchange with ion resins failed to reduce the ion content to below 100 ppt, and the water content rose to 60 ppm, meeting only the G3 grade ultra-clean, high-purity solvent requirements.

[0125] Therefore, liquid membrane dehydration can reduce the water content of IPA to 60ppm. When the liquid material contacts the untreated zeolite membrane, more ions will be dissolved, and the dissolution amount is about 2ppm. In addition, when stainless steel contacts the liquid material, more ions will be dissolved, and the dissolution amount is greater than 1ppm, which will seriously affect the service life of the ion exchange resin and the treatment efficiency of the ion resin. In this way, even through membrane dehydration combined with resin deionization process, it is impossible to obtain ultra-clean high-purity reagents higher than G3 grade.

[0126] The embodiments of the present application have been described in detail above in conjunction with specific implementation methods. However, the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other unless there is a conflict.

Claims

1. A method for preparing ultrapure isopropyl alcohol, characterized in that: The preparation method comprises the following steps: The SEMI-G3 grade isopropyl alcohol is fed into a vaporization device through a raw material conveying device to obtain vaporized isopropyl alcohol; The vaporized isopropyl alcohol is processed through a vapor-liquid separation device and then transported to a separation membrane assembly for treatment to obtain an isopropyl alcohol solution, wherein the separation membrane assembly has undergone a dissolution reduction pretreatment; The isopropyl alcohol solution is treated with an ion exchange resin to obtain the ultrapure isopropyl alcohol, wherein the ultrapure isopropyl alcohol has a single ion content of 1-10 ppt and a water content of less than 10 ppm; Wherein, the dissolution reduction pretreatment comprises the following steps: The separation membrane assembly is placed in an organic solvent for surface cleaning, and then the organic matter and ions on the surface of the separation membrane assembly are washed with ultra-clean deionized water, and the water on the surface of the separation membrane assembly is blown away with nitrogen having a volume fraction greater than 99.9999% in a Class 1000 clean room for standby use; or The dissolution reduction pretreatment comprises the following steps: The separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, and then the organic matter and ions on the surface of the separation membrane assembly after ion exchange are washed with ultra-clean deionized water. In a Class 1000 clean room, the water on the surface of the separation membrane assembly is blown away with N2 with a volume fraction greater than 99.9999% for standby use.

2. The preparation method according to claim 1, characterized in that The dissolution reduction pretreatment comprises the following steps: The separation membrane assembly is placed in an organic solvent for surface cleaning, and then the organic matter and ions on the surface of the separation membrane assembly are washed with ultra-clean deionized water. In a Class 1000 clean room, the water on the surface of the separation membrane assembly is blown away with nitrogen having a volume fraction greater than 99.9999% for standby use; The above-mentioned spare separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, and then the organic matter and ions on the surface of the separation membrane assembly after ion exchange are washed with ultra-clean deionized water. In a Class 1000 clean room, N2 with a volume fraction greater than 99.9999% is used to blow away the water on the surface of the separation membrane assembly to obtain the separation membrane assembly that has undergone dissolution reduction pretreatment.

3. The preparation method according to claim 1, characterized in that When the separation membrane assembly is placed in an organic solvent for surface cleaning, the organic solvent includes one or more of ethanol, isopropanol, n-propanol, acetone and / or tetrahydrofuran; When the separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, the inorganic salt solution contains an inorganic salt solute and a solvent, wherein the inorganic salt solute contains one or more of lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, strontium nitrate, barium hydroxide, magnesium acetate, calcium acetate, copper nitrate and / or ferric chloride, and the solvent contains one or more of methanol, ethanol, n-propanol, isopropanol, acetone and / or tetrahydrofuran.

4. The preparation method according to claim 2, characterized in that The organic solvent includes one or more of ethanol, isopropanol, n-propanol, acetone and / or tetrahydrofuran; The inorganic salt solution comprises an inorganic salt solute and a solvent, wherein the inorganic salt solute comprises one or more of lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, strontium nitrate, barium hydroxide, magnesium acetate, calcium acetate, copper nitrate and / or ferric chloride, and the solvent comprises one or more of methanol, ethanol, n-propanol, isopropanol, acetone and / or tetrahydrofuran.

5. The preparation method according to claim 1, characterized in that When the separation membrane assembly is placed in an organic solvent for surface cleaning, the cleaning comprises: heating the organic solvent containing the separation membrane assembly to 30-100° C. under bubbling conditions, treating for 1-6 hours, and repeating the treatment process 1-5 times; When the separation membrane assembly is placed in an inorganic salt solution with a concentration of 0.01-1M for ion exchange, the ion exchange includes: bubbling the inorganic salt solution containing the separation membrane assembly and heating it to 30-100°C for 1-6 hours, and repeating the treatment process 1-6 times.

6. The preparation method according to claim 2, characterized in that The cleaning comprises: heating the organic solvent containing the separation membrane assembly to 30-100° C. under bubbling conditions, treating for 1-6 hours, and repeating the treatment process 1-5 times; The ion exchange comprises: bubbling the inorganic salt solution containing the separation membrane assembly and heating it to 30-100° C., treating it for 1-6 hours, and repeating the treatment process 1-6 times.

7. The preparation method according to claim 1 or 2, characterized in that The separation membrane component includes a molecular sieve zeolite membrane.

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