Isopropanol waste liquid recycling and purifying system and method for semiconductor production

Abstract

The application discloses a kind of isopropanol waste liquid recovery purification system and method for semiconductor production, it is related to organic solvent waste liquid separation and recovery technical field.The system includes the pretreatment unit, azeotropic rectification unit, vapor permeation membrane dehydration unit and depth refining unit in turn along isopropanol waste liquid flow direction communication, and with azeotropic rectification unit coupling heat pump heat supply unit;Pretreatment unit includes particulate filter and located before active carbon fiber filter of heated separation component;Azeotropic rectification unit forms rich isopropanol production material and is sent into inorganic molecular sieve / ceramic composite membrane component and carries out dehydration;Depth refining unit removes ionic impurity and small particulate matter by cation exchange column, anion exchange column and terminal ultrafiltration component in turn;Heat pump heat supply unit supplies column still kettle reboiling process after tower top side heat is promoted.This application can reduce coking and membrane pollution risk, and improve isopropanol recovery purity, stability and energy utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of organic solvent waste liquid separation and recycling technology, and in particular to a system and method for recycling and purifying isopropanol waste liquid used in semiconductor production. Background Technology

[0002] Isopropanol, with its moderate volatility, low surface tension, and minimal residue, is widely used in semiconductor wafer cleaning, post-etching rinsing, dehydration and drying, and LCD panel manufacturing processes. After wafers are cleaned with ultrapure water, high-purity isopropanol is typically used for displacement dehydration or drying to reduce watermarks, particle adhesion, and the risk of micro-pattern collapse. As semiconductor manufacturing precision continues to increase, the requirements for controlling moisture, metal ions, organic residues, and microparticles in isopropanol also become more stringent.

[0003] In semiconductor manufacturing processes, the waste isopropanol solution after use is typically no longer a simple isopropanol-water mixture, but rather contains a variety of contaminants, including water, photoresist residue, organic impurities introduced during etching or cleaning, trace metal ions, salt residues, and particulate matter. Among these, some photoresist residues, high-boiling-point organic compounds, or antioxidant components are prone to oxidation, polymerization, or coking under heating conditions. These substances then adhere to the surfaces of heaters, distillation column internals, or membrane separation components, leading to scaling, clogging, reduced membrane flux, and abnormal product color. Therefore, the recovery and purification of isopropanol waste solution used in semiconductor manufacturing requires not only solving the separation problem between isopropanol and water, but also the synergistic removal of organic contaminants, metal ions, and particulate matter.

[0004] Existing isopropanol wastewater recovery technologies mainly include distillation or rectification, adsorption, membrane separation, and ion exchange. Distillation or rectification processes are relatively stable and can remove some moisture and volatile impurities. However, isopropanol and water have an azeotropic relationship, making it difficult for ordinary rectification to obtain high-purity isopropanol that meets electronic grade requirements. Furthermore, the heating of the reboiler and the condensation at the top of the column consume a lot of energy. Adsorption can selectively remove some moisture or organic impurities, but the adsorbent capacity is limited, requiring frequent regeneration or replacement during use, making it unsuitable for long-term continuous, high-flow-rate wastewater recovery scenarios. Membrane separation, especially pervaporation or steam permeation membrane separation, can overcome the isopropanol-water azeotropic limitation and is suitable for deep dehydration. However, membrane modules are sensitive to photoresist residues, high-boiling-point organic matter, and particulate matter in the feed. Without effective pretreatment, problems such as membrane fouling, flux decline, and shortened cleaning cycles can easily occur. Ion exchange can further reduce the content of metal ions or anions, but its function is relatively limited, and resin debris or particulate matter shedding can lead to secondary particulate pollution.

[0005] Therefore, existing technologies that rely solely on distillation, adsorption, membrane separation, or ion exchange are generally insufficient to simultaneously meet the requirements of high purity, high recovery rate, low energy consumption, and long-term stable operation for isopropanol wastewater from semiconductor manufacturing. Even when several processes are simply connected in series, without a systematic design addressing issues such as pre-heat removal of easily coking organic matter, staged dehydration of the isopropanol-water azeotropic system, control of isopropanol loss on the membrane permeate side, control of metal ions and terminal particulate matter, and recovery of distillation heat, problems such as severe membrane fouling, excessive moisture or metal ion content in the product, significant loss of effective isopropanol, and high operating energy consumption may still exist. Therefore, it is necessary to provide a recovery and purification system and method suitable for isopropanol wastewater from semiconductor manufacturing to achieve the staged removal of particulate matter, organic pollutants, moisture, ionic impurities, and fine particulate matter, and to improve the system's continuous operation stability and energy utilization efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a system and method for recycling and purifying isopropanol waste liquid used in semiconductor production, in order to solve the problems of easy coking of organic matter leading to pollution of heating equipment and membrane modules, difficulty in breaking the azeotropic limit by ordinary distillation, insufficient recovery rate and stability of membrane separation, and difficulty in meeting electronic grade requirements for ionic impurities and particulate matter in the recovered product during the existing isopropanol waste liquid recycling process, so as to achieve continuous, low-energy consumption, high-yield and high-purity recycling of isopropanol waste liquid.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A semiconductor manufacturing isopropanol waste liquid recovery and purification system includes a pretreatment unit, an azeotropic distillation unit, a vapor permeation membrane dehydration unit, a deep purification unit, and a heat pump heating unit coupled to the azeotropic distillation unit, which are connected sequentially along the flow direction of the isopropanol waste liquid. The pretreatment unit includes a particulate filter and an activated carbon fiber filter. The activated carbon fiber filter is located downstream of the particulate filter and before all the heated separation components of the azeotropic distillation unit. The azeotropic distillation unit includes a distillation column, a reflux condenser connected to the top of the distillation column, and a reboiler connected to the bottom of the distillation column for heat exchange. The reflux condenser has a reflux branch connected to the top reflux port of the distillation column and an isopropanol-rich collection branch connected to the vapor permeate membrane dehydration unit. The vapor permeation membrane dehydration unit includes a vaporization superheating component, an inorganic molecular sieve / ceramic composite membrane component, and a product condensation component connected sequentially along the isopropanol-rich outflow branch. The permeation side of the inorganic molecular sieve / ceramic composite membrane component is connected to a vacuum condensation component, and the vacuum condensation component has a permeate condensate return end that returns to the feed side of the pretreatment unit. The deep purification unit includes a cation exchange column, an anion exchange column, and a terminal ultrafiltration component that are sequentially connected to the product condensation assembly. The heat pump heating unit is coupled to the top of the distillation column or the reflux condenser on the heat absorption side and to the reboiler on the heat release side, so that after the isopropanol waste liquid is filtered by an activated carbon fiber filter to remove easily coking organic matter, it is then subjected to azeotropic distillation enrichment, vapor permeation membrane dehydration, ion exchange and terminal ultrafiltration purification in sequence.

[0008] Optionally, the particulate filter is a basket filter, and the activated carbon fiber filter includes a shell and multiple layers of activated carbon fiber felt disposed inside the shell. The liquid outlet of the basket filter is connected to the liquid inlet of the activated carbon fiber filter, so that the isopropanol waste liquid can be sequentially intercepted by particulate matter and adsorbed by organic matter before entering the azeotropic distillation unit.

[0009] Optionally, the distillation column is provided with a feed inlet connected to the pretreatment unit, and the condensation reflux assembly includes a top condenser, a reflux tank, a reflux regulating branch, and a product regulating branch. The reflux regulating branch connects the reflux tank with the top reflux port of the distillation column, and the product regulating branch constitutes the isopropanol-rich product branch and is connected to the vapor permeate membrane dehydration unit.

[0010] Optionally, the gasification superheating assembly includes a feed preheater and a superheater connected in sequence, and the inorganic molecular sieve / ceramic composite membrane assembly includes a tubular membrane shell and an inorganic molecular sieve membrane tube disposed within the tubular membrane shell. The inner side of the inorganic molecular sieve membrane tube constitutes the feed side, and the outer side of the inorganic molecular sieve membrane tube constitutes the permeation side.

[0011] Optionally, the liquid outlet of the product condensation component is connected to the liquid inlet of the cation exchange column, the liquid outlet of the cation exchange column is connected to the liquid inlet of the anion exchange column, and the liquid outlet of the anion exchange column is connected to the liquid inlet of the terminal ultrafiltration component. The terminal ultrafiltration component includes a hollow fiber ultrafiltration membrane for intercepting ion exchange resin debris and fine particulate matter.

[0012] Optionally, the vacuum condensation assembly includes a permeate-side condenser, a permeate collection tank, and a vacuum pump that are sequentially connected to the permeate side of the inorganic molecular sieve / ceramic composite membrane assembly, and the permeate condensate return end is connected to the permeate collection tank and the feed side of the pretreatment unit.

[0013] Optionally, the heat pump heating unit includes a heat pump compressor, an expansion valve, and a heat pump circulation pipeline. The evaporation section of the heat pump circulation pipeline is heat-exchange connected to the top side of the distillation column or the condensation reflux assembly, and the condensation section of the heat pump circulation pipeline is heat-exchange connected to the reboiler, so that the heat from the top side of the azeotropic distillation unit is boosted by the heat pump compressor and supplied to the reboiler.

[0014] Optionally, it also includes an online detection and control unit, which includes a moisture detector, a flow detector, a temperature detector, or a pressure detector disposed in at least one of the condensation reflux assembly, the vapor permeation membrane dehydration unit, and the deep purification unit, and is controlled and connected to at least one of the condensation reflux assembly, the vaporization superheating assembly, the vacuum condensation assembly, or the heat pump heating unit.

[0015] To achieve the above-mentioned technical objectives, the present invention also adopts the following technical solution: A method for recovering and purifying isopropanol waste liquid used in semiconductor manufacturing, comprising the following steps: The isopropanol waste liquid generated during semiconductor production is passed sequentially through a particulate filter and an activated carbon fiber filter to remove particulate matter and easily coking organic matter before the isopropanol waste liquid is heated. The pretreated isopropanol waste liquid is sent to the azeotropic distillation unit for distillation and separation, so that the material on the top side of the distillation column is condensed and refluxed to form reflux material and isopropanol-rich product. The isopropanol-rich extracted material is fed into a vapor permeation membrane dehydration unit. After being vaporized and superheated, it enters an inorganic molecular sieve / ceramic composite membrane module, allowing water molecules to enter a vacuum condensation module through the permeation side of the inorganic molecular sieve / ceramic composite membrane module, and causing isopropanol vapor on the retentate side to be condensed into dehydrated isopropanol through a product condensation module. The dehydrated isopropanol is sequentially fed into a cation exchange column, an anion exchange column, and a terminal ultrafiltration module to remove ionic impurities and fine particulate matter, thereby obtaining recovered isopropanol. During the operation of the azeotropic distillation unit, the heat from the top side of the distillation column or the reflux condenser is boosted by a heat pump heating unit and supplied to the bottom side of the distillation column for reboiling.

[0016] Optionally, the isopropanol-rich extracted material is vaporized and superheated before entering the inorganic molecular sieve / ceramic composite membrane module in a gaseous state. The permeation side of the inorganic molecular sieve / ceramic composite membrane module is maintained under negative pressure, and the permeate condensate collected by the vacuum condensation module is returned to the feed side of the particulate filter or the activated carbon fiber filter.

[0017] The main advantages of this invention compared to existing technologies are as follows: This invention connects a pretreatment unit, an azeotropic distillation unit, a vapor permeation membrane dehydration unit, and a deep purification unit sequentially along the flow direction of isopropanol waste liquid. The activated carbon fiber filter in the pretreatment unit is placed before all the heated separation components of the azeotropic distillation unit. This allows the system to intercept particulate matter and adsorb photoresist residues, easily oxidized or easily polymerized high-boiling-point organic matter before the isopropanol waste liquid is heated. This reduces the risk of these impurities coking, adhering, and contaminating the membrane components during heating, distillation, or membrane dehydration, thereby improving the stability of continuous system operation.

[0018] This invention couples an azeotropic distillation unit and a vapor permeation membrane dehydration unit, allowing the azeotropic distillation unit to first enrich and stabilize the pretreated isopropanol waste liquid, and then the vapor permeation membrane dehydration unit to deeply dehydrate the isopropanol-rich material. This avoids the problem that simple distillation cannot overcome the isopropanol-water azeotropic limitation, and reduces the separation load and contamination risk when the membrane module directly treats complex low-concentration waste liquid.

[0019] This invention, by sequentially connecting a cation exchange column, an anion exchange column, and a terminal ultrafiltration component after the product condensation assembly, can further remove metal cations, anions, ion exchange resin debris, and fine particulate matter after membrane dehydration, making the recovered isopropanol more suitable for semiconductor production reuse requirements in terms of moisture, ion impurities, and particulate matter control.

[0020] This invention, by setting up a heat pump heating unit coupled to the azeotropic distillation unit and setting a permeate condensate reflux end for the vacuum condensation assembly, can, on the one hand, increase the heat from the top side of the distillation column or the reflux condensation assembly and supply it to the reboiler, reducing the consumption of external heating media and the heat loss from condensation at the top of the column; on the other hand, it can allow the condensate from the membrane permeate side to flow back to the feed side of the pretreatment unit to recover the small amount of isopropanol entrained therein, thereby taking into account both the system's energy utilization efficiency and the overall isopropanol recovery rate. Attached Figure Description

[0021] Figure 1 This is a system architecture diagram of the isopropanol waste liquid recovery and purification system of the present invention; Figure 2 This is a flowchart illustrating the steps of the isopropanol waste liquid recovery and purification method of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments. It should be understood that the following embodiments are used to illustrate the technical solution and implementation process of the present invention, and are not intended to limit the scope of protection of the present invention. Without departing from the technical concept of the present invention, those skilled in the art can make adaptive adjustments to some filtration accuracy, tower internals, number of membrane modules, heat exchanger specifications, arrangement of detection instruments, and control parameters according to the water content, organic impurity content, treatment scale, and product recycling requirements of the isopropanol waste liquid to be treated.

[0023] This invention targets isopropanol wastewater generated during semiconductor manufacturing. This isopropanol wastewater is not a simple isopropanol-water binary system, but typically contains water, photoresist residue, organic impurities introduced by etching or cleaning processes, catechol or amine residues, trace metal ions, acid radicals, and particulate matter. Direct distillation is difficult to achieve directly with electronic-grade isopropanol due to the azeotropic nature of isopropanol and water. Membrane separation easily contaminates membrane modules due to photoresist residue, high-boiling-point organic matter, and particulate matter. Ion exchange treatment alone at the downstream end fails to address pre-membrane fouling and azeotropic dehydration issues. Therefore, this invention couples particulate matter interception, organic matter adsorption, azeotropic distillation enrichment, deep dehydration via vapor permeate membrane, ion exchange purification, terminal ultrafiltration, and heat pump heating into a continuous treatment system, allowing different types of pollutants to be treated sequentially according to their physical properties and removal difficulty.

[0024] Example 1: As Figure 1 As shown, this embodiment provides an isopropanol waste liquid recovery and purification system 100 for semiconductor manufacturing. The system 100 includes a pretreatment unit 10, an azeotropic distillation unit 20, a vapor permeation membrane dehydration unit 30, and a deep purification unit 40, sequentially connected along the flow direction of the isopropanol waste liquid, and includes a heat pump heating unit 50 coupled to the azeotropic distillation unit 20. The system 100 may also include an online detection and control unit 60 for detecting moisture, temperature, pressure, flow rate, liquid level, or differential pressure at key points, and adjusting the return flow rate, output rate, heating power, vacuum degree, permeate condensate return flow rate, or heat pump heating capacity based on the detection results.

[0025] I. Preprocessing Unit.

[0026] The pretreatment unit 10 includes a particulate filter 11 and an activated carbon fiber filter 12. The particulate filter 11 is installed on the isopropanol waste liquid feed pipeline. The inlet end of the particulate filter 11 is connected to the waste liquid conveying pipeline, and the outlet end of the particulate filter 11 is connected to the inlet end of the activated carbon fiber filter 12. The outlet end of the activated carbon fiber filter 12 is connected to the feed side of the azeotropic distillation unit 20.

[0027] The particulate filter 11 is used to intercept larger particles before the waste liquid enters the adsorption and thermal separation process. Particulate matter may include equipment pipeline debris, inorganic salt crystals, suspended solids, photoresist fragments, or other solid impurities carried by the waste liquid. In one embodiment, the particulate filter 11 is a basket filter. The basket filter has a removable filter basket located inside the filter housing. Isopropanol waste liquid passes through the filter screen from the outside or inside of the basket and is discharged, thus completing the particulate interception. The filter basket can be made of stainless steel mesh with a filtration precision of 100 mesh, which can be adjusted to other filtration precisions depending on the particulate matter content of the waste liquid. The particulate filter 11 not only reduces product particulate matter but also protects the downstream activated carbon fiber filter 12, distillation column 21, reboiler 24, and inorganic molecular sieve / ceramic composite membrane module 32, preventing large particulate impurities from causing blockage or localized deposition.

[0028] The activated carbon fiber filter 12 is located downstream of the particulate filter 11 and before all the heated separation components of the azeotropic distillation unit 20. The heated separation components include at least the distillation column 21, the reboiler 24, the vaporization superheater 31, and the inorganic molecular sieve / ceramic composite membrane assembly 32, which operates under high-temperature gas phase conditions. In other words, isopropanol waste liquid must pass through the activated carbon fiber filter 12 before entering the aforementioned heated components.

[0029] The activated carbon fiber filter 12 includes a housing 121 and a multi-layer activated carbon fiber felt 122 disposed within the housing 121. The housing 121 has an inlet, an outlet, and a drain. The multi-layer activated carbon fiber felt 122 is arranged at intervals or stacked along the liquid flow direction, allowing isopropanol waste liquid to pass through multiple adsorption paths within the housing 121 before being discharged. The activated carbon fiber felt 122 has a large specific surface area and microporous structure, enabling it to adsorb photoresist residues, high-boiling-point organic matter, easily oxidized components such as catechols, amine residues, surfactants, and other easily polymerizable or coking organic matter.

[0030] In this embodiment, the key to the activated carbon fiber filter 12 lies not in simply using an adsorption material, but in placing it before all major thermal separation processes. Because photoresist residues and high-boiling-point organic compounds in semiconductor isopropanol waste liquid are easily oxidized, polymerized, or coked under heating conditions, if they directly enter the distillation column 21, reboiler 24, or membrane module, they may form a deposition layer on the column internals, heat exchange surfaces, or membrane surfaces, leading to tray or packing blockage, decreased reboiler heat exchange efficiency, reduced membrane flux, or shortened membrane cleaning cycles. This embodiment, by performing activated carbon fiber adsorption before heating, removes or reduces the aforementioned easily coking organic compounds before they enter the azeotropic distillation unit 20, thereby reducing the pollution risk of downstream thermal and membrane separation processes at the source.

[0031] II. Azeotropic Distillation Unit.

[0032] The azeotropic distillation unit 20 includes a distillation column 21, a reflux condenser 22, and a reboiler 24. The distillation column 21 has a feed inlet 211, a top vapor outlet 212, a top reflux outlet 213, and a bottom outlet 214. The liquid outlet of the pretreatment unit 10 is connected to the feed inlet 211 of the distillation column 21. The distillation column 21 can be a packed column or a plate column. In one embodiment, the distillation column 21 is filled with structured corrugated plate packing, with a theoretical plate number of 30-50. The column body, internal components, and piping in contact with the material are made of stainless steel to accommodate the continuous separation of the isopropanol waste liquid system.

[0033] The reflux condenser assembly 22 is connected to the top side of the distillation column 21. The reflux condenser assembly 22 includes a top condenser 221, a reflux tank 222, a reflux regulating branch 223, and a product regulating branch 224. The top vapor outlet 212 is connected to the inlet of the top condenser 221, and the condensate outlet of the top condenser 221 is connected to the reflux tank 222. The reflux tank 222 is connected to the top reflux port 213 of the distillation column 21 via the reflux regulating branch 223, and to the vapor permeate membrane dehydration unit 30 via the product regulating branch 224. The product regulating branch 224 constitutes an isopropanol-rich product branch.

[0034] It is important to note that the condensation reflux assembly 22 in this embodiment does not rely on the natural stratification of the isopropanol-water condensate. Isopropanol and water are miscible; therefore, this embodiment does not consider "natural phase separation" as a necessary condition for achieving isopropanol-rich product extraction. Instead, it obtains an isopropanol-rich product with a higher isopropanol content relative to the feed through vapor-liquid mass transfer, top condensation, partial reflux, and partial extraction in the distillation column 21. This isopropanol-rich product can approximate the isopropanol-water azeotropic composition, or it can be formulated into an isopropanol-rich material suitable for entering the vapor permeate membrane dehydration unit 30, depending on the column operating conditions and feed composition. In other words, the function of the azeotropic distillation unit 20 is to provide a stable membrane feed with controlled water content for membrane dehydration, rather than solely achieving final electronic-grade purification.

[0035] The reboiler 24 is heat-exchange connected to the reboiler of the distillation column 21. The reboiler 24 can be a thermosiphon reboiler, a kettle reboiler, or a forced circulation reboiler. The material on the reboiler side of the distillation column 21 enters the reboiler 24, is heated, generates rising steam, and returns to the distillation column 21 to participate in the distillation process. The reboiler outlet 214 is used to discharge water-rich materials, high-boiling-point residues, or other heavy components. Because the pretreatment unit 10 has already removed particulate matter and easily coking organic matter upstream, the contaminant load entering the reboiler 24 and the distillation column 21 is reduced, which helps to reduce reboiler coking, column internals contamination, and heat exchange surface deposition.

[0036] The operating logic of the azeotropic distillation unit 20 is as follows: the pretreated isopropanol waste liquid enters the distillation column 21 through the feed inlet 211; the reboiler 24 heats the material in the column bottom, causing rising steam to form in the column; the vapor phase at the top of the column is condensed by the top condenser 221 and enters the reflux tank 222; part of the condensate in the reflux tank 222 returns to the top reflux port 213 through the reflux regulating branch 223, and the other part of the condensate enters the vapor permeate membrane dehydration unit 30 as the isopropanol-rich product through the outflow regulating branch 224; the water-rich material or heavy component on the column bottom side is discharged through the column bottom outlet 214.

[0037] III. Steam permeation membrane dehydration unit.

[0038] The vapor permeate membrane dehydration unit 30 includes a vaporization superheating component 31, an inorganic molecular sieve / ceramic composite membrane component 32, a product condensation component 33, and a vacuum condensation component 34. The vaporization superheating component 31 is located upstream of the inorganic molecular sieve / ceramic composite membrane component 32 along the discharge direction of the isopropanol-rich outflow branch. The product condensation component 33 is connected to the retardation side outlet of the inorganic molecular sieve / ceramic composite membrane component 32, and the vacuum condensation component 34 is connected to the permeate side of the inorganic molecular sieve / ceramic composite membrane component 32.

[0039] The vaporization superheating assembly 31 includes a feed preheater 311 and a superheater 312 connected in sequence. The isopropanol-rich collected material output from the collection regulating branch 224 first enters the feed preheater 311, and then enters the superheater 312. The feed preheater 311 preheats the liquid isopropanol-rich collected material to a near-vaporized state, while the superheater 312 continues to provide heat, causing the isopropanol-rich collected material to form a gaseous phase or a superheated gaseous phase before entering the inorganic molecular sieve / ceramic composite membrane assembly 32. In one embodiment, the material temperature before entering the inorganic molecular sieve / ceramic composite membrane assembly 32 is 120°C to 130°C. This temperature range is used to keep the isopropanol-rich collected material in a gaseous phase state, preventing droplets from entering the membrane assembly and causing localized flooding or affecting membrane separation stability.

[0040] The inorganic molecular sieve / ceramic composite membrane module 32 includes a tubular membrane housing 321 and an inorganic molecular sieve membrane tube 322 disposed within the tubular membrane housing 321. The inorganic molecular sieve membrane tube 322 can be a NaA type molecular sieve / ceramic composite membrane tube. The inorganic molecular sieve membrane tube 322 has a feed side and a permeate side. In one specific arrangement, the inner side of the inorganic molecular sieve membrane tube 322 constitutes the feed side, and the outer side constitutes the permeate side; in another arrangement, the outer side constitutes the feed side, and the inner side constitutes the permeate side. Regardless of the arrangement, it should be ensured that isopropanol-rich gaseous material flows on the feed side, and water molecules can preferentially permeate through the molecular sieve membrane layer to enter the permeate side.

[0041] The dehydration mechanism of the inorganic molecular sieve / ceramic composite membrane module 32 is as follows: After the isopropanol-rich gaseous material enters the feed side, water molecules, due to their small molecular size and strong affinity for the molecular sieve channels, are preferentially adsorbed and permeate through the membrane to the permeate side; isopropanol molecules are mainly retained on the feed side and flow along the feed side to the retention side outlet. The vacuum condensation module 34 maintains a negative pressure on the permeate side, creating a water partial pressure difference across the membrane, thereby enhancing the driving force for water transmembrane transfer. In this embodiment, the deep dehydration of the isopropanol-rich extracted material is achieved through the combination of gas-phase entry into the membrane and negative pressure on the permeate side.

[0042] The product condensation assembly 33 includes a product condenser 331 and a product buffer tank 332. The filtration side outlet of the inorganic molecular sieve / ceramic composite membrane assembly 32 is connected to the product condenser 331, and the liquid outlet of the product condenser 331 is connected to the product buffer tank 332. Isopropanol vapor after membrane dehydration enters the product condenser 331 and is condensed into dehydrated isopropanol liquid, which then enters the product buffer tank 332 for temporary storage before being transported to the deep purification unit 40.

[0043] The vacuum condensation assembly 34 includes a permeate-side condenser 341, a permeate collection tank 342, and a vacuum pump 343. The permeate-side outlet of the inorganic molecular sieve / ceramic composite membrane assembly 32 is connected to the permeate-side condenser 341, the condensate outlet of the permeate-side condenser 341 is connected to the permeate collection tank 342, and the vacuum pump 343 is connected to the gas phase side of either the permeate-side condenser 341 or the permeate collection tank 342 to maintain a negative pressure on the permeate side of the membrane assembly. In one embodiment, the absolute pressure on the permeate side is 100 Pa to 500 Pa.

[0044] The permeate collection tank 342 is equipped with a permeate condensate return end 344. The permeate condensate return end 344 is connected to the feed side of the pretreatment unit 10 via a return pipeline. Specifically, the permeate condensate return end 344 can be connected to the feed side of the particulate filter 11 or the feed side of the activated carbon fiber filter 12. The membrane permeate condensate is mainly water, but may contain a small amount of isopropanol. Direct discharge would result in the loss of effective isopropanol. In this embodiment, the permeate condensate is returned to the feed side of the pretreatment unit 10, allowing the entrained isopropanol to re-enter the particulate filtration, activated carbon fiber adsorption, azeotropic distillation, and membrane dehydration processes, thereby improving the overall system recovery rate.

[0045] IV. Deep Refining Unit.

[0046] The deep purification unit 40 includes a cation exchange column 41, an anion exchange column 42, and a terminal ultrafiltration module 43. The outlet of the product condensation module 33 is connected to the inlet of the cation exchange column 41, the outlet of the cation exchange column 41 is connected to the inlet of the anion exchange column 42, the outlet of the anion exchange column 42 is connected to the inlet of the terminal ultrafiltration module 43, and the outlet of the terminal ultrafiltration module 43 is connected to the product discharge pipeline 44.

[0047] Cation exchange column 41 is filled with cation exchange resin to remove metal cations such as Na⁺, K⁺, Fe²⁺, Fe³⁺, Cu²⁺, Ca²⁺, and Mg²⁺ from dehydrated isopropanol. Anion exchange column 42 is filled with anion exchange resin to remove anionic impurities such as Cl⁻, SO₄²⁻, and NO₃⁻, as well as some organic acid impurities. Cation exchange columns 41 and anion exchange columns 42 can be arranged in series, or a spare column can be provided to ensure continuous system operation during resin regeneration or replacement.

[0048] The terminal ultrafiltration assembly 43 is located downstream of the anion exchange column 42. The terminal ultrafiltration assembly 43 includes a hollow fiber ultrafiltration membrane for intercepting resin debris, microbial fragments, and fine particulate matter that may detach during the ion exchange process. In one embodiment, the hollow fiber ultrafiltration membrane has a pore size of 0.02 μm and a molecular weight cutoff of 10,000 Da. The terminal ultrafiltration assembly 43 is positioned after ion exchange, thus enabling end-point control of particulate risks that may be introduced by the ion exchange column itself. Through this arrangement, the deep purification unit 40 not only reduces the content of ionic impurities but also intercepts terminal particulate matter, making the recovered isopropanol more suitable for reuse in semiconductor production.

[0049] V. Heat pump heating unit.

[0050] The heat pump heating unit 50 is coupled to the azeotropic distillation unit 20 and is used to boost the heat from the top side of the distillation column 21 or the reflux condenser assembly 22 before supplying it to the reboiler 24. The heat pump heating unit 50 includes a heat pump compressor 51, an expansion valve 52, and a heat pump circulation line 53. The heat pump circulation line 53 includes an evaporation section 531 and a condensation section 532. The evaporation section 531 is heat-exchange connected to the top side of the distillation column 21 or the reflux condenser assembly 22, and the condensation section 532 is heat-exchange connected to the reboiler 24.

[0051] During operation, the heat pump working fluid absorbs low-grade heat released from the top side of the distillation column 21 or the reflux condenser assembly 22 in the evaporation section 531. After absorbing heat, the heat pump working fluid enters the heat pump compressor 51, where its temperature and pressure increase due to compression. It then enters the condensation section 532, where it releases heat to the reboiler 24. After releasing heat, the heat pump working fluid returns to the evaporation section 531 after being depressurized by the expansion valve 52, forming a closed loop. Through this loop, the heat that would otherwise be carried away by cooling water at the top of the column is boosted and returned to the reboiler, reducing the consumption of external heat sources.

[0052] In another embodiment, the heat pump heating unit 50 can also employ a direct compression heating method for the overhead vapor phase. Specifically, the overhead vapor phase outlet 212 of the distillation column 21 is connected to the inlet side of the heat pump compressor 51, and the exhaust side of the heat pump compressor 51 is connected to the heat source side of the reboiler 24. After being compressed and heated by the heat pump compressor 51, the overhead vapor phase enters the heat source side of the reboiler 24, where it exchanges heat with the bottom material to form condensate. This method also belongs to the heat pump heating method that raises the heat on the top side of the column and supplies it to the bottom side for the reboiling process.

[0053] In this embodiment, the heat pump heating unit 50 is not an independent energy-saving accessory, but rather forms a thermally coupled relationship with the overhead condensation and reboiler reboiler processes of the azeotropic distillation unit 20. The distillation column 21 requires simultaneous overhead condensation and reboiler heating, and the heat pump heating unit 50 connects the two through a heat boosting process, enabling the distillation section to achieve stable output of isopropanol-rich product while reducing overall energy consumption.

[0054] VI. Online detection and control unit.

[0055] To ensure the continuous and stable operation of this system 100 and to avoid describing the control process only with abstract functions, this embodiment further explains the specific detection objects, judgment criteria, and adjustment actions of the online detection and control unit 60.

[0056] The online detection and control unit 60 includes a controller 61 and one or more of the following: a moisture detector, a flow detector, a temperature detector, a pressure detector, a level detector, and a differential pressure detector, all electrically connected to the controller 61. The controller 61 can be a DCS control system or a PLC control system. The controller 61 is controlled by at least one of the following: a reflux regulating valve on the reflux regulating branch 223, a product regulating valve on the product regulating branch 224, the heating control terminal of the superheater 312, the vacuum pump 343, the reflux valve on the permeate condensate reflux terminal 344, and the heat pump compressor 51.

[0057] A moisture detector and a flow detector are installed at the reflux assembly 22, the reflux tank 222, or the outflow regulating branch 224. The moisture detector detects the moisture content in the isopropanol-rich outflow, and the flow detector detects the outflow flow rate. The controller 61 compares the moisture detection value with a preset in-membrane moisture range. When the moisture content of the isopropanol-rich outflow exceeds the upper limit of the preset in-membrane moisture range, the controller 61 increases the opening of the reflux regulating branch 223 or decreases the opening of the outflow regulating branch 224, allowing more overhead condensate to return to the distillation column 21, improving the separation intensity within the column, and reducing the amount of high-moisture material entering the vapor permeate membrane dehydration unit 30. When the moisture content is within the preset in-membrane moisture range, the controller 61 maintains or adjusts the opening of the outflow regulating branch 224 according to the throughput requirements, ensuring a stable feed to the vapor permeate membrane dehydration unit 30.

[0058] Temperature and pressure detectors are installed at the gasification superheating assembly 31, at the outlet of the raw material preheater 311, the outlet of the superheater 312, or the inlet of the membrane module. The temperature detector detects the temperature of the material entering the inorganic molecular sieve / ceramic composite membrane module 32, and the pressure detector detects the pressure before the membrane. The controller 61 compares the inlet temperature with a preset gas-phase inlet temperature range. When the inlet temperature is lower than the lower limit of the preset gas-phase inlet temperature range, the controller 61 increases the heating power of the superheater 312 or decreases the isopropanol-rich outflow rate, ensuring the material reaches a gas phase or superheated gas phase state before entering the membrane module. When the inlet temperature is higher than the upper limit of the preset gas-phase inlet temperature range, the controller 61 reduces the heating power of the superheater 312 to avoid overheating leading to increased energy consumption or increased heat load on the membrane module.

[0059] At the vacuum condensation assembly 34, a pressure detector is installed on the permeate side of the inorganic molecular sieve / ceramic composite membrane assembly 32 or the gas phase side of the permeate collection tank 342, and a level detector is installed in the permeate collection tank 342. The pressure detector is used to detect the permeate side pressure, and the level detector is used to detect the liquid level in the permeate collection tank 342. When the permeate side pressure is higher than the upper limit of the preset negative pressure range, the controller 61 increases the suction capacity of the vacuum pump 343 or issues a control command to check the condensation load of the permeate side condenser 341; when the liquid level in the permeate collection tank 342 reaches the preset reflux level, the controller 61 opens the reflux valve of the pipeline where the permeate condensate reflux end 344 is located, so that the permeate condensate flows back to the feed side of the pretreatment unit 10; when the liquid level drops to the preset low level, the controller 61 closes or reduces the opening of the reflux valve to prevent gas backflow or affect the vacuum stability of the permeate side.

[0060] At the deep purification unit 40, pressure detectors or differential pressure detectors are installed before and after the cation exchange column 41, anion exchange column 42, and terminal ultrafiltration module 43, respectively. The controller 61 determines the blockage or resin contamination within the column based on the pressure difference before and after the exchange column. When the pressure difference before and after the cation exchange column 41 or anion exchange column 42 exceeds the corresponding differential pressure threshold, the controller 61 issues control commands to switch to a standby column, reduce the feed flow rate, or perform regeneration or resin replacement. When the pressure difference before and after the terminal ultrafiltration module 43 exceeds the ultrafiltration differential pressure threshold, the controller 61 issues control commands to clean or replace the terminal ultrafiltration membrane. Through the above-described specific detection and adjustment logic, the system 100 can have executable control modes in the event of moisture fluctuations, membrane-side pressure fluctuations, permeate accumulation, or abnormal pressure differences in the purification unit.

[0061] Temperature and pressure detectors are installed at the heat pump heating unit 50, on the evaporation section 531, condensation section 532, or heat source side of the reboiler 24 in the heat pump circulation pipeline 53. The controller 61 adjusts the operating frequency of the heat pump compressor 51 or the flow rate of the heat pump working fluid according to the heat load demand of the reboiler 24 and the reboiler temperature of the distillation column 21. When the reboiler temperature is below the target reboiler temperature range, the controller 61 increases the operating frequency of the heat pump compressor 51 or increases the auxiliary heat source supply; when the reboiler temperature is above the target reboiler temperature range, the controller 61 decreases the operating frequency of the heat pump compressor 51 or reduces the auxiliary heat source supply. Thus, the heat pump heating unit 50 can match the separation load of the azeotropic distillation unit 20, rather than simply operating as a fixed-power device.

[0062] Example 2: Figure 2 As shown, this embodiment provides a method for recovering and purifying isopropanol waste liquid used in semiconductor production using the system 100 described in Embodiment 1. The method includes the following steps.

[0063] S1. Pretreatment before heating.

[0064] Isopropanol wastewater generated during semiconductor production is fed into pretreatment unit 10. The wastewater first passes through particulate filter 11, which intercepts large particles, crystalline salt particles, suspended solids, and photoresist fragments. After particulate filtration, the wastewater enters activated carbon fiber filter 12, passing through a multi-layer activated carbon fiber felt 122. Photoresist residue, high-boiling-point organic matter, easily oxidized components such as catechols, surfactants, and other easily coking organic matter are adsorbed by the activated carbon fiber felt 122. This step is completed before the wastewater enters distillation column 21, reboiler 24, and vaporization superheater assembly 31, reducing the risk of coking and contamination in subsequent heating processes.

[0065] S2, azeotropic distillation enrichment.

[0066] Pretreated isopropanol waste liquid is fed into distillation column 21. The pretreated material enters distillation column 21 through feed inlet 211 and undergoes vapor-liquid mass transfer with the reflux liquid in the column under the heating effect of reboiler 24. The vapor phase at the top of the column enters the top condenser 221 through the top vapor phase outlet 212, and after condensation, enters the reflux tank 222. Part of the condensate in reflux tank 222 returns to the top reflux port 213 through reflux regulating branch 223, and the other part of the condensate enters the vapor permeate membrane dehydration unit 30 as isopropanol-rich collected material through the collection regulating branch 224. The water-rich material or material containing heavy components on the bottom side of the column is discharged through the bottom outlet 214.

[0067] In this step, the moisture content of the isopropanol-rich feedstock is maintained within a range suitable for membrane dehydration by adjusting the opening of the reflux regulating branch 223 and the outflow regulating branch 224. The function of the azeotropic distillation unit 20 is to enrich isopropanol and stabilize the membrane feedstock, not to obtain the final electronic-grade product on its own.

[0068] S3, vaporization superheating and vapor permeation membrane dehydration.

[0069] The isopropanol-rich collected material is fed into the gasification superheater assembly 31. The isopropanol-rich collected material sequentially passes through the feed preheater 311 and the superheater 312, forming a gaseous or superheated gaseous material. In one embodiment, the inlet temperature is controlled at 120°C to 130°C. The gaseous isopropanol-rich material enters the feed side of the inorganic molecular sieve / ceramic composite membrane assembly 32. Water molecules permeate through the inorganic molecular sieve membrane tube 322 into the permeate side, while isopropanol vapor is mainly retained on the retrieval side and discharged from the retrieval side outlet. The isopropanol vapor on the retrieval side enters the product condenser 331 for condensation, yielding dehydrated isopropanol.

[0070] Simultaneously, a vacuum pump 343 maintains a negative pressure on the permeate side of the inorganic molecular sieve / ceramic composite membrane module 32. In one embodiment, the absolute pressure on the permeate side is 100 Pa to 500 Pa. Water and a small amount of entrained isopropanol on the permeate side enter the permeate-side condenser 341 for condensation, and the condensate enters the permeate collection tank 342. After the liquid level in the permeate collection tank 342 reaches the preset reflux level, the permeate condensate is returned to the feed side of the pretreatment unit 10 via the permeate condensate reflux end 344, allowing the entrained isopropanol to re-participate in the system recovery.

[0071] S4, ion exchange and terminal ultrafiltration purification.

[0072] The dehydrated isopropanol obtained from the product condensation assembly 33 is fed into the deep purification unit 40. The dehydrated isopropanol first enters the cation exchange column 41, where metal cations are removed by the cation exchange resin; then it enters the anion exchange column 42, where anionic impurities and some organic acid impurities are removed by the anion exchange resin; finally, it enters the terminal ultrafiltration assembly 43, where ion exchange resin debris, microbial fragments, and fine particulate matter are intercepted by the hollow fiber ultrafiltration membrane. The isopropanol after terminal ultrafiltration is discharged through the product discharge pipeline 44 and is returned to the product storage tank or reuse pipeline as recovered isopropanol.

[0073] S5, heat recovery from distillation for heating.

[0074] During the S2 azeotropic distillation process, the heat pump heating unit 50 is activated. The evaporation section 531 of the heat pump circulation pipeline 53 absorbs heat from the top side of the distillation column 21 or the reflux condenser assembly 22. The heat pump working fluid, after being compressed and heated by the heat pump compressor 51, enters the condensation section 532 and releases heat to the reboiler 24 for reboiling of the bottom material. The heat pump working fluid is then depressurized by the expansion valve 52 and returns to the evaporation section 531 to continue circulating. Through this step, the low-grade heat at the top of the column is increased and used for reboiling on the bottom side, reducing external heat supply and heat loss from top condensation.

[0075] Example 3: This example further illustrates a continuous operation process based on Examples 1 and 2.

[0076] The isopropanol waste liquid to be treated has an isopropanol mass fraction of 50%–85%. The waste liquid is pumped into a basket filter, where larger particles are intercepted, and then it enters an activated carbon fiber filter. The activated carbon fiber filter contains multiple layers of activated carbon fiber felt. After the waste liquid passes through these multiple layers of activated carbon fiber felt, the content of photoresist residue and easily coking organic matter is reduced.

[0077] The pretreated material enters the feed inlet in the middle of the distillation column. The vapor phase at the top of the distillation column is condensed by the top condenser and enters the reflux tank. The condensate in the reflux tank is divided into two streams: one stream flows back to the top of the distillation column via the reflux regulating branch, and the other stream flows into the feed preheater as the isopropanol-rich product via the product regulating branch. The water-rich product on the bottom side is discharged through the bottom outlet. An online moisture detector monitors the moisture content of the isopropanol-rich product. When the moisture content is too high, the reflux ratio is increased or the product ratio is decreased; when the moisture content is within the preset range, stable product output is maintained.

[0078] The isopropanol-rich feedstock is heated to 120℃~130℃ via a feed preheater and superheater, and then enters the NaA-type molecular sieve / ceramic composite membrane module in a gaseous state. The permeate side of the membrane module is maintained at an absolute pressure of 100Pa~500Pa by a vacuum pump. Water molecules permeate through the membrane into the permeate side and are condensed in the permeate-side condenser. Isopropanol vapor is discharged on the retrieval side and condensed in the product condenser. Once the permeate condensate in the permeate collection tank reaches the preset level, it is returned to the feed side of the pretreatment unit.

[0079] The dehydrated isopropanol output from the product condenser sequentially enters a cation exchange column, an anion exchange column, and a terminal ultrafiltration unit. The cation exchange column removes metal cations, the anion exchange column removes anionic impurities, and the terminal ultrafiltration unit intercepts resin debris and fine particulate matter. The recovered isopropanol after terminal ultrafiltration enters the product storage tank.

[0080] During distillation column operation, the heat pump heating unit continuously absorbs heat from the top of the column or the reflux condenser and supplies the heat to the reboiler. The controller adjusts the operating frequency of the heat pump compressor based on the column bottom temperature and reboiling load to maintain a stable reboiling process. If the column bottom temperature is below the set range, the operating frequency of the heat pump compressor is increased or auxiliary heating is added; if the column bottom temperature is above the set range, the operating frequency of the heat pump compressor is decreased.

[0081] Through the above continuous operation process, the isopropanol waste liquid sequentially undergoes pretreatment before heating, azeotropic distillation enrichment, vapor permeate membrane dehydration, deep purification, and heat pump recovery. The connections between each unit, the flow of materials, and the control actions are all clearly defined, enabling those skilled in the art to complete the system construction and operation based on this specification without requiring additional creative effort.

[0082] Example 4: This example illustrates several alternative implementation methods.

[0083] In the pretreatment unit 10, the particulate filter 11 can be a basket filter, a pipeline filter, or a bag filter, as long as it can intercept particulate matter in the waste liquid before entering the activated carbon fiber filter 12. The activated carbon fiber felt 122 in the activated carbon fiber filter 12 can adopt a multi-layer stacked structure or a wound packing structure, as long as it can ensure that the isopropanol waste liquid forms sufficient contact with the activated carbon fiber before entering the azeotropic distillation unit 20.

[0084] In the azeotropic distillation unit 20, the distillation column 21 can be a packed column or a plate column. The reflux condenser assembly 22 can be equipped with a reflux tank 222, or it can be equipped with a reflux buffer tank and a product buffer tank. As long as the condensate at the top of the column can form a reflux branch and an isopropanol-rich product branch, and the isopropanol-rich product enters the vapor permeate membrane dehydration unit 30, the distillation enrichment and membrane feed stabilization functions of this invention can be achieved.

[0085] In the vapor permeate membrane dewatering unit 30, the inorganic molecular sieve / ceramic composite membrane module 32 may include one set of membrane modules, or multiple sets of membrane modules connected in parallel or in series. When the throughput is large, multiple sets of membrane modules can be arranged in parallel; when a higher dewatering depth is required, multiple sets of membrane modules can be arranged in series. The inorganic molecular sieve membrane tube 322 can be a NaA type molecular sieve / ceramic composite membrane tube, or other inorganic molecular sieve / ceramic composite membrane tubes with selective permeability to water molecules.

[0086] In the deep purification unit 40, the cation exchange column 41 and the anion exchange column 42 can be configured with one in use and one in standby, so as to switch when the resin is saturated or the pressure difference is abnormal. The terminal ultrafiltration module 43 can be a hollow fiber ultrafiltration membrane, or it can be other terminal membrane filtration modules that can intercept resin debris and fine particulate matter.

[0087] In the heat pump heating unit 50, either an indirect heat pump circulation method or a direct compression heating method for the overhead vapor phase can be used. When using the indirect heat pump circulation method, the evaporation section 531 of the heat pump circulation pipeline 53 is connected to the top side of the distillation column 21 or the condenser reflux assembly 22 for heat exchange, and the condensation section 532 is connected to the reboiler 24 for heat exchange. When using the direct compression method, the overhead vapor phase of the distillation column 21 is compressed and heated by the heat pump compressor 51 before entering the heat source side of the reboiler 24. Both methods are used to raise the heat from the top side of the column and supply it to the reboiler side for the reboiling process.

[0088] In summary, this invention does not simply list filtration, distillation, membrane separation, and ion exchange, but rather configures the system according to the removal sequence of pollutants and the material state change patterns in semiconductor isopropanol waste liquid: first, particulate matter and easily coking organic matter are removed before heating; then, a stable isopropanol-rich feedstock is formed through azeotropic distillation; next, deep dehydration is performed through a vapor-permeable membrane; subsequently, deep purification in the electronic-grade direction is achieved through cation exchange, anion exchange, and terminal ultrafiltration; simultaneously, isopropanol loss is reduced by permeate condensate reflux; and heat from the top of the tower is recovered by a heat pump heating unit for use in the reboiler. The structural relationships, material flow direction, heat flow direction, and control logic of this technical solution can all be directly implemented using the above embodiments.

[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for recovering and purifying isopropanol waste liquid used in semiconductor manufacturing, characterized in that, It includes a pretreatment unit, an azeotropic distillation unit, a vapor permeation membrane dehydration unit, and a deep purification unit connected sequentially along the flow direction of the waste liquid, as well as a heat pump heating unit and a controller; The pretreatment unit includes a particulate filter and an activated carbon fiber filter connected in sequence. The activated carbon fiber filter removes easily coking organic matter before all heated separation components of the azeotropic distillation unit. The azeotropic distillation unit includes a distillation column, a reflux condenser connected to the top of the column, and a reboiler connected to the bottom of the column for heat exchange. The reflux condenser condenses the vapor phase at the top of the column and returns the condensate to the top outlet of the column via a reflux branch, and outputs the isopropanol-rich condensate via an isopropanol-rich outlet branch. The vapor permeation membrane dehydration unit includes a vaporization superheating component, an inorganic molecular sieve / ceramic composite membrane component, and a product condensation component connected sequentially along the isopropanol-rich outflow branch. The vaporization superheating component vaporizes and superheats the isopropanol-rich condensate before it enters the inorganic molecular sieve / ceramic composite membrane component, whose permeation side is connected to a vacuum condensation component. The vacuum condensation component is provided with a permeation condensate return end that returns to the feed side of the pretreatment unit. The deep purification unit includes a cation exchange column, an anion exchange column, and a terminal ultrafiltration component that are sequentially connected to the product condensation assembly. The heat pump heating unit has a closed working fluid circulation loop, with its heat absorption side connected to the top of the distillation column or the condensation reflux assembly for heat exchange, and its heat release side connected to the reboiler for heat exchange. The controller is connected to the extraction regulating valve on the isopropanol-rich extraction branch and receives the moisture content detection value and the membrane inlet temperature detection value of the isopropanol-rich condensate. When the moisture content is higher than the upper limit of the preset membrane inlet moisture range, the opening of the extraction regulating valve is reduced. When the membrane inlet temperature is lower than the lower limit of the preset gas phase inlet membrane temperature range, the extraction flow rate of the isopropanol-rich liquid is reduced.

2. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The particulate filter is a basket filter, and the activated carbon fiber filter includes a shell and multiple layers of activated carbon fiber felt disposed inside the shell. The liquid outlet of the basket filter is connected to the liquid inlet of the activated carbon fiber filter, so that the isopropanol waste liquid can be sequentially intercepted by particulate matter and adsorbed by organic matter before entering the azeotropic distillation unit.

3. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The distillation column is provided with a feed inlet connected to the pretreatment unit. The condensation reflux assembly includes a top condenser, a reflux tank, a reflux regulating branch, and a collection regulating branch. The reflux regulating branch connects the reflux tank with the top reflux port of the distillation column. The collection regulating branch constitutes the isopropanol-rich collection branch and is connected to the vapor permeation membrane dehydration unit.

4. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The gasification superheating assembly includes a raw material preheater and a superheater connected in sequence. The inorganic molecular sieve / ceramic composite membrane assembly includes a tubular membrane shell and an inorganic molecular sieve membrane tube disposed within the tubular membrane shell. The inner side of the inorganic molecular sieve membrane tube constitutes the raw material side, and the outer side of the inorganic molecular sieve membrane tube constitutes the permeation side.

5. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The liquid outlet of the product condensation component is connected to the liquid inlet of the cation exchange column, the liquid outlet of the cation exchange column is connected to the liquid inlet of the anion exchange column, and the liquid outlet of the anion exchange column is connected to the liquid inlet of the terminal ultrafiltration component. The terminal ultrafiltration component includes a hollow fiber ultrafiltration membrane for intercepting ion exchange resin debris and fine particulate matter.

6. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The vacuum condensation assembly includes a permeate-side condenser, a permeate collection tank, and a vacuum pump that are sequentially connected to the permeate side of the inorganic molecular sieve / ceramic composite membrane assembly. The permeate condensate return end is connected to the permeate collection tank and the feed side of the pretreatment unit.

7. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, The heat pump heating unit includes a heat pump compressor, an expansion valve, and a heat pump circulation pipeline. The evaporation section of the heat pump circulation pipeline is heat-exchange connected to the top side of the distillation column or the condensation reflux assembly, and the condensation section of the heat pump circulation pipeline is heat-exchange connected to the reboiler, so that the heat from the top side of the azeotropic distillation unit is boosted by the heat pump compressor and supplied to the reboiler.

8. The isopropanol waste liquid recovery and purification system for semiconductor manufacturing according to claim 1, characterized in that, It also includes an online detection and control unit, which includes a moisture detector, a flow detector, a temperature detector or a pressure detector located in at least one of the condensation reflux assembly, the vapor permeation membrane dehydration unit and the deep purification unit, and is controlled and connected to at least one of the condensation reflux assembly, the vaporization superheating assembly, the vacuum condensation assembly or the heat pump heating unit.

9. A method for recovering and purifying isopropanol waste liquid used in semiconductor manufacturing, using the isopropanol waste liquid recovery and purification system for semiconductor manufacturing as described in any one of claims 1-8, characterized in that, Includes the following steps: The isopropanol waste liquid generated during semiconductor production is passed sequentially through a particulate filter and an activated carbon fiber filter to remove particulate matter and easily coking organic matter before the isopropanol waste liquid is heated. The pretreated isopropanol waste liquid is sent to the azeotropic distillation unit for distillation and separation, so that the material on the top side of the distillation column is condensed and refluxed to form reflux material and isopropanol-rich product. The isopropanol-rich extracted material is fed into a vapor permeation membrane dehydration unit. After being vaporized and superheated, it enters an inorganic molecular sieve / ceramic composite membrane module, allowing water molecules to enter a vacuum condensation module through the permeation side of the inorganic molecular sieve / ceramic composite membrane module, and causing isopropanol vapor on the retentate side to be condensed into dehydrated isopropanol through a product condensation module. The dehydrated isopropanol is sequentially fed into a cation exchange column, an anion exchange column, and a terminal ultrafiltration module to remove ionic impurities and fine particulate matter, thereby obtaining recovered isopropanol. During the operation of the azeotropic distillation unit, the heat from the top side of the distillation column or the reflux condenser is boosted by a heat pump heating unit and supplied to the bottom side of the distillation column for reboiling.

10. The method for recovering and purifying isopropanol waste liquid used in semiconductor manufacturing according to claim 9, characterized in that, The isopropanol-rich extracted material is vaporized and superheated before entering the inorganic molecular sieve / ceramic composite membrane module in a gaseous state. The permeation side of the inorganic molecular sieve / ceramic composite membrane module is maintained under negative pressure. The permeate condensate collected by the vacuum condensation module is returned to the feed side of the particulate filter or the activated carbon fiber filter.

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