Method for preparing isopropyl alcohol

Abstract

The present invention relates to a method for preparing isopropyl alcohol, comprising the steps of: supplying a propylene monomer and reaction water as a feed stream to a reactor to produce a gas-phase reaction product comprising isopropyl alcohol; purifying isopropyl alcohol from the gas-phase reaction product and recovering process water; and passing the process water through an arsenic removal device comprising a first filtration layer, an adsorbent layer, and a second filtration layer.

Description

Method for producing isopropyl alcohol

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0121956, filed September 7, 2024, and Korean Patent Application No. 10-2025-0101524, filed July 25, 2025, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present disclosure relates to a method for producing isopropyl alcohol, and more particularly, to a method for producing high-quality isopropyl alcohol by removing arsenic contained in process water circulating within the process.

[0005] Isopropyl alcohol (IPA) is used in a variety of applications, including as a solvent for cleaning agents, industrial paints and reagents, paints, and inks in the electronics industry, including semiconductor and liquid crystal display (LCD) manufacturing.

[0006] Isopropyl alcohol can be produced by reacting propylene monomer with water. For example, a gaseous reaction between propylene monomer and water is performed in a reaction unit to obtain a reaction product comprising isopropyl alcohol, unreacted propylene monomer, unreacted water, and byproducts. The gaseous reaction product is then passed through a subsequent process tower to separate the propylene monomer, water, and byproducts, thereby purifying the isopropyl alcohol.

[0007] In this process, the water used as reaction water is heated and supplied to the reactor to react with the propylene monomer to produce isopropyl alcohol, and the unreacted water is separated in the isopropyl alcohol purification unit, cooled, and recycled as process water to be used for washing the absorption tower and the organic matter (hydrocarbon) removal tower, and some of it is discharged as waste water. In this way, the water introduced during the isopropyl alcohol manufacturing process is continuously circulated as process water, and the process water may contain trace amounts of arsenic.

[0008] Arsenic degrades the quality of IPA and therefore needs to be removed. Typically, IPA purification units use distillation and other methods to remove impurities. However, arsenic decomposes or sublimates below the operating temperature of the distillation column in the IPA purification unit, vaporizing into a gaseous phase. This makes complete removal by distillation difficult. Therefore, to produce high-quality isopropyl alcohol, the development of a technology capable of effectively removing arsenic circulating within the process is essential.

[0009] The problem to be solved in the present disclosure is to provide a method for producing high-quality isopropyl alcohol by continuously removing arsenic from process water in an isopropyl alcohol production process in order to solve the problem mentioned in the above background art.

[0010] However, the problems to be solved by the present disclosure are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0011] According to one embodiment of the present disclosure for solving the above problem, a method for producing isopropyl alcohol is provided, including: supplying propylene monomer and reaction water as a feed stream to a reactor to produce a gaseous reaction product including isopropyl alcohol; purifying isopropyl alcohol from the gaseous reaction product and recovering process water; and passing the process water through an arsenic removal device including a first filter layer, an adsorbent layer, and a second filter layer.

[0012] Additionally, the step of passing the process water through an arsenic removal device including a first filter layer, an adsorbent layer, and a second filter layer may include sequentially passing the process water through the first filter layer, the adsorbent layer, and the second filter layer inside the arsenic removal device.

[0013] The method for producing isopropyl alcohol of the present disclosure can produce high-quality IPA by continuously removing arsenic in process water through adsorption and preventing arsenic from circulating within the process.

[0014] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0015] FIG. 1 is a process diagram illustrating the overall process flow of a method for producing isopropyl alcohol according to one embodiment of the present disclosure.

[0016] Figure 2 is a process diagram that embodies process A of Figure 1.

[0017] FIG. 3 illustrates the structure of an arsenic removal device used in a method for producing isopropyl alcohol according to one embodiment of the present disclosure.

[0018] FIG. 4 illustrates the structure of an arsenic removal device used in a method for producing isopropyl alcohol according to one embodiment of the present disclosure.

[0019] FIG. 5 illustrates the structure of an arsenic removal device used in a method for producing isopropyl alcohol according to one embodiment of the present disclosure.

[0020] Figure 6 shows the arsenic removal rate according to the spatial residence time in an embodiment of the present disclosure.

[0021] Figure 7 is a graph comparing the number of days required for the arsenic concentration in a product to reach 4,000% to 100% of the management standard depending on the arsenic removal rate in the circulating water.

[0022] The terms or words used in the description and claims of this disclosure should not be construed as limited to their usual or dictionary meanings, but should be construed as meanings and concepts that conform to the technical idea of ​​this disclosure, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own disclosure in the best way.

[0023] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0024] The singular form of a noun corresponding to an item may include one or more of said items, unless the relevant context clearly indicates otherwise.

[0025] In this disclosure, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in the corresponding phrase, or all possible combinations thereof.

[0026] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0027] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0028] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in the present disclosure are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0029] The terms “include” or “have” are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in the present disclosure, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0030] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0031] When we say that a component is “on” another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0032] In addition, the terms "about", "substantially", etc. used in this disclosure are used in the sense of or close to the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute numerical values ​​are mentioned to aid understanding of this disclosure.

[0033] The term "stream" as used herein may refer to the flow of fluid within a process, and may also refer to the fluid itself flowing within a pipe. Specifically, the stream may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may include one or more components of gas, liquid, and solid.

[0034] The term "upper" as used herein, unless otherwise specified, refers to a point 0% to 20% in height downward from the top of the device, and may specifically refer to the top (top). In addition, the term "lower" refers to a point 80% to 100% in height downward from the top of the device, and may specifically refer to the bottom (bottom).

[0035] Additionally, “pressure” as referred to in the present disclosure means gauge pressure measured based on atmospheric pressure.

[0036] The term “Empty Bed Contact Time (EBCT)” used in the present disclosure means the time that a fluid substantially remains in a device or a specific area when passing a fluid that flows continuously through the device or a specific area, and is calculated as “(volume of the device) / (volume flow rate of the fluid passing through the device)” or “(volume of the specific area) / (volume flow rate of the fluid passing through the specific area)”, and its unit is time (h). For example, 1 m 3 0.5 m in a device with a volume of 3 If the fluid is continuously flowed at / h, the spatial residence time becomes (1 / 0.5) = 2h, which can be equivalent to the fluid remaining in the device for 2 hours.

[0037] During the IPA manufacturing process, arsenic circulates within the process due to reasons such as arsenic leakage from the carrier during catalyst replacement, leading to arsenic extraction within the IPA product. Specifically, although IPA is produced through a gas phase reaction, some of the arsenic decomposes and sublimates within the distillation column, resulting in detection of arsenic in the gas phase. This makes it difficult to completely remove arsenic through distillation. Consequently, arsenic remains circulated within the process water, resulting in detection of arsenic within the product over a long period of time, leading to a decline in quality.

[0038] Accordingly, the present disclosure seeks to remove arsenic present in circulating water and IPA products containing arsenic. More specifically, the present disclosure seeks to continuously remove arsenic from process water, which contains the highest arsenic content, through adsorption, thereby preventing arsenic from circulating within the process, thereby producing high-quality isopropyl alcohol.

[0039] A method for producing isopropyl alcohol according to one embodiment of the present disclosure comprises the steps of (S1) supplying propylene monomer and reaction water as a feed stream to a reactor to produce a gaseous reaction product comprising isopropyl alcohol; (S2) purifying isopropyl alcohol from the gaseous reaction product and recovering process water; and (S3) passing the process water through an arsenic removal device comprising a first filter layer, an adsorbent layer, and a second filter layer. In addition, the step (S3) may include sequentially passing the process water through the first filter layer, the adsorbent layer, and the second filter layer inside the arsenic removal device.

[0040] FIG. 1 illustrates a method for producing isopropyl alcohol according to one embodiment of the present disclosure, and isopropyl alcohol can be produced using a system including a reactor (100), an absorption tower (201), a gas purification unit (202), an organic matter removal tower (301), a water removal tower (302), an IPA separation unit (303), and an arsenic removal device (400).

[0041] According to one embodiment, the gaseous reaction product obtained from the reactor (100) passes through an absorption tower (201), a gas purification unit (202), an organic matter removal tower (301), a water removal tower (302), and an IPA separation unit (303) to obtain purified IPA, and the water recovered from the bottom of the water removal tower is used as process water. After passing through an arsenic removal device (400), a portion of the process water (W) is transferred to the absorption tower (201) and the organic matter removal tower (301) to be used as wash water, and the remainder is discharged as waste water.

[0042] Water, i.e., reaction water, which is typically used as a raw material for producing isopropyl alcohol, is heated from an initial temperature of 30°C to 50°C (e.g., 40°C) to a target temperature of at least 100°C for gas phase reaction with propylene monomer and then supplied to the reactor.

[0043] Process water (W) may include unreacted water and wash water recovered in the process of purifying isopropyl alcohol by separating unreacted propylene monomer, byproducts, etc. while the gaseous reaction product passes through the subsequent process, such as the absorption tower (201), organic matter removal tower (301), and water removal tower (302).

[0044] Figure 2 illustrates in more detail part A of Figure 1, which is a post-process tower. Referring to Figure 2, process water (W) recovered from the water removal tower (302) can be continuously removed of arsenic by passing through an arsenic removal device (400) for use in washing a pre-process tower (e.g., an absorption tower (201) and an organic matter removal tower (301)).

[0045] The size (volume) of the above arsenic removal device (400) can be appropriately designed and changed according to the flow rate of the process water (W) fed into the arsenic removal device. For example, the space residence time (Empty Bed Contact Time; EBCT) of the process water (W) passing through the arsenic removal device can be 10 minutes to 6 hours, preferably 10 minutes to 4 hours, and more preferably 10 minutes to 1.5 hours. When the arsenic removal device satisfies the space residence time range, the arsenic removal efficiency can be improved. In addition, when the arsenic removal efficiency is improved, the product production volume can be increased, thereby improving economic feasibility.

[0046] Fig. 3 illustrates the structure of an arsenic removal device (400) according to one embodiment. Referring to Fig. 3, the arsenic removal device (400) may have a structure in which a first filter layer (11), an adsorbent layer (20), and a second filter layer (12) are sequentially stacked therein, and may be arranged in a vertical direction. Accordingly, the process water (W) may be introduced into one side of the arsenic removal device (400), sequentially pass through the first filter layer (11), the adsorbent layer (20), and the second filter layer (12), and then be discharged from the other side.

[0047] The first filter layer (11) and the second filter layer (12) are provided to suppress the dissolution of the arsenic adsorbent described later and to provide a physical filtration effect, and their types may be the same or different. For example, activated carbon, sand, zeolite, silica gel, or metal mesh may be used as the first filter layer (11) and the second filter layer (12).

[0048] In addition, the first filter layer (11) and the second filter layer (12) within the arsenic removal device (400) may be provided to independently have a spatial residence time of 1 minute to 30 minutes, specifically 1 minute to 20 minutes, and more specifically 1 minute to 10 minutes. By satisfying the above range, the suppression of adsorbent dissolution and the physical filtration effect can be maximized.

[0049] As illustrated in Fig. 3, the adsorbent layer (20) is provided to adsorb and remove trace amounts of arsenic contained in the process water (W), and is located between the first filter layer (11) and the second filter layer (12).

[0050] Arsenic adsorbents that can be used as the adsorbent layer (20) include, for example, metal oxide-based adsorbents such as iron hydroxide, activated alumina, titanium oxide, alpha iron oxide, and gamma iron oxide, and ion exchange resins. The arsenic adsorbents may have different sizes depending on their shape and type. For example, the metal oxide-based adsorbents may be in a pellet or granular form, and may have a size ranging from 0.5 mm to 100 mm in diameter, but is not limited thereto. The ion exchange resin may be in a gel or microporous type, and may have a size ranging from 300 μm to 1,200 μm, but is not limited thereto.

[0051] In addition, the adsorbent layer (20) may be provided to have a spatial residence time of 10 minutes to 5 hours, preferably 10 minutes to 3 hours, and more preferably 10 minutes to 1 hour within the arsenic removal device (400). By satisfying the above range, 60 wt% or more, specifically 60 wt% to 99.5 wt%, and more specifically 64 wt% to 99.3 wt% of arsenic can be removed within the process water (W) flow rate passing through the arsenic removal device.

[0052] According to one embodiment of the present disclosure, the adsorbent layer (20) may be divided into first to n-th regions, and each of the first to n-th regions may be filled with first to n-th adsorbents. At this time, each region may be filled with the same or different types of adsorbents, but includes at least one arsenic adsorbent. That is, the types of the first to n-th adsorbents may be the same or different. Compared to a structure in which the adsorbent layer is not divided, in a structure in which the adsorbent layer is divided into a plurality of regions, the length of the path through which the process water passes through the adsorbent layer increases, so that the area and time for which the process water comes into contact with the arsenic adsorbent are sufficiently secured. Accordingly, the arsenic adsorption efficiency can be improved without changing the size of the device.

[0053] In addition, when the inside of the arsenic removal device is provided with the adsorbent layer (20) having a structure in which the first to n-th regions are partitioned, when the process water (W) passes through the arsenic removal device (400), the process water (W) is supplied to one side of the first region (1), sequentially passes from the first region to the n-th region, and then can be discharged in one direction selected from one side and the other side of the n-th region. For example, when the device is partitioned into an odd number of regions, the process water (W) can be discharged to the other side of the n-th region, and when the device is partitioned into an even number of regions, the process water (W) can be discharged to one side of the n-th region.

[0054] In addition, the above n may be an integer of 2 to 5, preferably 3 to 4. For example, the interior of the arsenic removal device (400) may be divided into two or more, preferably 2 to 5, and more preferably 3 to 4 regions by partition walls (30), and it may be preferable that the number of regions divided is odd.

[0055] Specifically, the partition wall (30) may be provided with a structure extending radially from the central axis of the arsenic removal device. In addition, the partition wall between the two adjacent regions among the first to n-th regions may be provided with a flow path with at least one side open so that process water can flow between the two regions. However, even if the first region where the process water inlet is located and the n-th region where the process water outlet is located are adjacent to each other, the partition wall between them should not have an open flow path. More specifically, a flow path open in the direction of the other side (C, E) may be formed in the partition wall between an odd region (e.g., the first region) and an even region (e.g., the second region), and a flow path open in the direction of the other side (B, D) may be formed in the partition wall between an even region (e.g., the second region) and an odd region (e.g., the third region). Through this structure, the process water injected into the adsorbent layer can be discharged after contacting all of the first to nth adsorbents within the first to nth regions.

[0056] Meanwhile, in order to prevent the arsenic adsorbent from leaking out of the arsenic removal device, a first filter layer (11) may be provided on the process water inlet side of the first region through which the process water passes first among the regions partitioned by the partition wall, and a second filter layer (12) may be provided on the process water outlet side of the nth region through which the process water passes last, but is not limited thereto. The types, shapes, sizes, and spatial residence times of the adsorbent layers and filter layers are as described above.

[0057] Furthermore, the side of the arsenic removal device may further be provided with an inlet (not shown) for introducing an adsorbent into the device and an outlet (not shown) for discharging the adsorbent to the outside. In this case, the inlet is positioned relatively upper, and the outlet is positioned relatively lower. When different types of adsorbents are used in each area, the lifespan, reusability, and reuse method may differ depending on the fluid. When the inlet and outlet are provided, the adsorbent inside the arsenic removal device can be replaced as needed.

[0058] FIG. 4 illustrates a structure in which an adsorbent layer (20) is partitioned into first to third regions (1, 2, 3) by partition walls (30a, 30b, 30c) in an arsenic removal device (400) according to one embodiment. The left drawing is a longitudinal cross-sectional view of the device, the upper right drawing is a cross-sectional view of one side (B) of the device, and the lower right drawing is a cross-sectional view of the other side (C) of the device.

[0059] As shown in Fig. 4, when the number of internal regions partitioned by the partition wall (30) is odd, it is preferable that process water (W) is introduced into one side of the arsenic removal device, passes through the adsorbent in each region, and then is discharged from the other side of the arsenic removal device.

[0060] Specifically, referring to FIG. 4, when the arsenic removal device (400) according to one embodiment is divided into a first region (1), a second region (2), and a third region (3) by partition walls (30a, 30b, 30c), process water (W) can be introduced into one side (B) of the first region (1), pass through the second region (2), and then be discharged into the other side (C) of the third region (3).

[0061] More specifically, the partition wall (30b) between the second region (2) and the third region (3) may have a structure in which one side (B) is open, and the partition wall (30a) between the first region (1) and the second region (2) may have a structure in which the other side (C) is open. In addition, one side (B) of the first region (1) may have a structure in which a pipe is connected or open so that process water (W) can be introduced, and the other side (C) of the third region (3) may have a structure in which a pipe is connected or open so that process water (W) can be discharged. Since the above arsenic removal device (400) has such a structure, process water (W) supplied from one side (B) can sequentially move in the direction of "one side of the first region (1) → the other side of the first region (1) → the other side of the second region (2) → one side of the second region (2) → one side of the third region (3) → the other side of the third region (3)" and finally be discharged in the direction of the other side (C) of the arsenic removal device (400).

[0062] FIG. 5 illustrates a structure in which an adsorbent layer (20) is divided into four regions by partition walls (30a, 30b, 30c, 30d) in the arsenic removal device (400) according to one embodiment. The left drawing is a longitudinal cross-sectional view of the device, the upper right drawing is a cross-sectional view of one side (D) of the device, and the lower right drawing is a cross-sectional view of the other side (E) of the device.

[0063] As shown in Fig. 5, when the number of internal regions partitioned by the partition wall (30) is an even number, process water (W) is injected into one side of the arsenic removal device, passes through the arsenic adsorbent in each region, and then can be discharged in the same direction as the process water injection direction.

[0064] Specifically, referring to FIG. 5, when the arsenic removal device (400) according to one embodiment is divided into a first region (1), a second region (2), a third region (3), and a fourth region (4) by partition walls (30a, 30b, 30c, 30d), process water (W) can be introduced into one side of the first region (1), pass through the second region (2) and the third region (3), and then be discharged through the fourth region (4).

[0065] More specifically, the partition wall (30b) between the second region (2) and the third region (3) may have a structure in which one side (D) is open, and the partition wall (30a) between the first region (1) and the second region (2) and the partition wall (30c) between the third region (3) and the fourth region (4) may have a structure in which the other side (E) is open. In addition, one side (D) of the first region (1) and the fourth region (4) may have a structure in which pipes are connected or open so that process water (W) can be independently introduced or discharged. Since the above arsenic removal device (400) has such a structure, process water (W) supplied from one side (D) can sequentially move in the direction of "one side of the first region (1) → the other side of the first region (1) → the other side of the second region (2) → one side of the second region (2) → one side of the third region (3) → the other side of the third region (3) → the other side of the fourth region (4) → one side of the fourth region (4)" and finally be discharged in the direction of one side (D) of the arsenic removal device (400).

[0066] Meanwhile, the temperature of the process water (W) passing through the arsenic removal device (400) may be 20°C to 150°C or 30°C to 60°C, and the temperature range may vary depending on the type of arsenic adsorbent.

[0067] According to one embodiment of the present disclosure, when the process water (W) discharged from the lower portion of the water removal tower (302) is passed through the arsenic removal device (400), as illustrated in FIG. 2, the process water (W) may be branched so that only a portion of the stream passes through the arsenic removal device (400). Specifically, the arsenic removal rate improves as a large amount of the process water (W) is passed through the arsenic removal device, but the amount may be excessive if all of the process water discharged from the water removal tower (302) is fed into the arsenic removal device. In this case, it is preferable to appropriately adjust the flow rate of the process water (W) fed into the arsenic removal device in consideration of the size (volume) of the arsenic removal device and / or an economical perspective. For example, based on the total volumetric flow rate of the process water, the flow rate ratio (v / v) of the process water passing through the arsenic removal device may be 1% or more, 2% or more, or 3% or more, and 10% or less, 15% or less, or 20% or less.

[0068] Additionally, two or more arsenic removal devices may be installed in parallel as needed. In this case, the process water (W) discharged from the bottom of the water removal tower is divided into two or more and passed through two or more arsenic removal devices, thereby increasing the arsenic removal rate in the process water.

[0069] Meanwhile, the process water (W) may be cooled by passing through a heat exchanger (not shown). For example, the cooled process water may be branched and used as wash water for the absorption tower (201) and the organic matter removal tower (301). In addition, some of the cooled process water may be treated as wastewater, and if necessary, after passing through an additional cooler, some of the water may be branched and used for temperature control of the wash water, and the remainder may be discharged as wastewater.

[0070] The reaction water is supplied to the reactor (100) and reacts in the gas phase with the propylene monomer to obtain a reaction product containing isopropyl alcohol.

[0071] Since only a portion of the propylene monomer used as the raw material is used in the reaction, the reaction product may include 65 to 85 wt% of unreacted propylene monomer, 4 to 8 wt% of isopropyl alcohol, and 5 to 30 wt% of water. In addition, the reaction product may further include other byproducts of high-boiling point organic substances such as isopropyl ether (DIPE), hexene, acetone, and n-propyl alcohol (NPA). Therefore, a post-process is performed to purify isopropyl alcohol from the reaction product.

[0072] First, the gaseous reaction product discharged from the reactor (100) is supplied to the absorption tower (201) and brought into contact with wash water to obtain an aqueous solution containing isopropyl alcohol. As described above, a portion of the process water (W) recovered from the water removal tower (302) at the rear end may be used as the wash water of the absorption tower (201).

[0073] Specifically, the reaction product may be supplied to the bottom of the absorption tower (201), and the wash water may be supplied to the top of the absorption tower (201). The isopropyl alcohol in the gas phase may be absorbed by the wash water and obtained as a lower liquid stream, and a gas phase stream containing unreacted propylene monomer may be separated from the top and recovered to the reactor (100).

[0074] The lower liquid stream of the absorption tower (201) may contain a small amount of unreacted propylene monomer, for example, 5 wt% or less or 2 wt% to 5 wt%, in addition to isopropyl alcohol and unreacted water.

[0075] In one embodiment of the present disclosure, the volumetric flow rate of the wash water supplied to the absorption tower (201) may be 15 vol% to 40 vol% or 15 vol% to 35 vol% of the flow rate of the reaction product. When the wash water is supplied at a flow rate within the above range, the absorption capacity of the isopropyl alcohol contained in the reaction product can be improved, while at the same time, the energy cost for the recovery of the wash water at the subsequent stage can be prevented from increasing excessively.

[0076] The above absorption tower (201) has a temperature of 90°C to 100°C or 90°C to 95°C and a pressure of 25 kg / cm 2 (g) to 40 kg / cm 2 (g) or 25 kg / cm 2 (g) to 35 kg / cm 2 (g) It can be operated at a pressure of . When the above operating conditions are satisfied, an upper discharge stream containing unreacted propylene monomer and a lower discharge stream containing isopropyl alcohol can be effectively separated.

[0077] The liquid stream containing isopropyl alcohol separated from the above absorption tower (201) can be supplied to a gas purification unit (202) and separated into an upper stream containing low-boiling-point components and a lower stream containing isopropyl alcohol, water, and by-products.

[0078] The upper stream containing the low-boiling-point component separated in the above gas purification unit (202) may contain unreacted propylene monomer and inert gases (e.g., ethane, propane).

[0079] The bottom stream separated from the above gas purification unit (202) may include isopropyl alcohol, water, and by-products (e.g., isopropyl ether (DIPE), hexene, n-propyl alcohol (NPA), etc.).

[0080] The above gas purification unit (202) may include one or more flash drums and one or more gas purification towers. First, low-boiling-point components are primarily separated from the flash drums, and then supplied to the gas purification tower to separate low-boiling-point components of unreacted propylene monomer and inert gas from the upper portion and trace amounts of high-boiling-point components from the lower portion.

[0081] Unreacted propylene monomer separated in the above gas purification unit (202) can be recovered to the reactor (100), and the inert gas can be branched off for exhaust.

[0082] Meanwhile, the bottom stream of the gas purification unit (202) is transferred to the IPA purification unit for isopropyl alcohol recovery. The IPA purification unit includes an organic matter removal tower (301), a water removal tower (302), and an IPA separation unit (303).

[0083] First, the bottom stream of the gas purification unit (202) is supplied to the organic matter removal tower (301), and can be separated into a liquid phase containing isopropyl alcohol and water and a liquid phase containing organic matter by contacting with wash water in the organic matter removal tower (301). As described above, a portion of the process water (W) recovered from the water removal tower (302) at the subsequent stage can be used as the wash water of the organic matter removal tower (301).

[0084] The alcohol component is dissolved by the above washing water, and the liquid phase containing isopropyl alcohol and water in the organic matter removal tower (301) is separated to the bottom, and the liquid phase containing the remaining organic matter can be removed in the decanter at the rear end of the connected condenser.

[0085] In one embodiment of the present disclosure, the volumetric flow rate of the wash water supplied to the organic matter removal tower (301) may be 60 vol% to 100 vol% or 65 vol% to 95 vol% of the bottom stream flow rate of the gas purification unit (202). When the wash water is supplied at a flow rate within the above range, the absorption capacity of the isopropyl alcohol contained in the stream can be improved, while at the same time, the energy cost for the recovery of the wash water at the subsequent stage can be prevented from increasing excessively.

[0086] The liquid phase containing isopropyl alcohol and water separated in the organic matter removal tower (301) may contain 3 to 10 wt% of isopropyl alcohol and 90 to 97 wt% of water. That is, most of the liquid phase contains washing water, and thus separation thereof is required.

[0087] Accordingly, the liquid phase containing isopropyl alcohol and water separated from the organic matter removal tower (301) is supplied to the water removal tower (302) to separate it into an upper stream containing isopropyl alcohol and a lower stream containing water.

[0088] The upper stream separated from the water removal tower (302) contains an azeotropic mixture of isopropyl alcohol and water, and may contain, for example, 80 to 90 wt% of isopropyl alcohol and 10 to 20 wt% of water.

[0089] Meanwhile, the bottom stream of the water removal tower (302) is recovered as process water (W), and then passes through an arsenic removal device (400) to remove arsenic, after which some of it is recycled as wash water and the remainder can be discharged as waste water.

[0090] The above water removal tower (302) has a temperature of 70°C to 150°C or 80°C to 140°C and a pressure of 1 kg / cm 2 (g) to 5 kg / cm 2 (g) or 1 kg / cm 2 (g) to 2 kg / cm2 It can be operated at a pressure of (g). When the above operating conditions are satisfied, an azeotropic mixture of isopropyl alcohol and water can be effectively separated.

[0091] Thereafter, the azeotropic mixture stream separated from the water removal tower (302) is supplied to an IPA separation unit (303) including an IPA purification tower and a solvent recovery tower to recover IPA.

[0092] For example, by introducing an organic solvent (e.g., cyclohexane, benzene, etc.) as an azeotrope into the IPA purification tower of the IPA separation unit (303), the azeotrope of isopropyl alcohol and water is broken, thereby obtaining isopropyl alcohol purified to high purity. In addition, a stream containing the azeotrope and water can be separated from the upper portion of the IPA purification tower, and then supplied to a solvent recovery tower to separate an upper stream of the azeotrope and a lower stream of water, and the upper stream of the azeotrope can be refluxed to the IPA purification tower.

[0093] In the present disclosure, if necessary, additional devices such as a distillation column, condenser, reboiler, valve, pump, separator, and mixer can be used.

[0094] Above, the method for manufacturing isopropyl alcohol according to the present disclosure has been described and illustrated in the drawings, but the description and illustration of the drawings describe and illustrate only the core components for understanding the present disclosure, and in addition to the processes and devices described and illustrated in the drawings, processes and devices not described and illustrated separately can be appropriately applied and utilized to carry out the method for manufacturing isopropyl alcohol according to the present disclosure.

[0095] Hereinafter, the present disclosure will be described in more detail through examples. However, the following examples are intended to further illustrate the present disclosure, and the scope of the present disclosure is not limited by the following examples.

[0096] [Example]

[0097] Example 1

[0098] Isopropyl alcohol was produced and purified according to the process system shown in Fig. 1 and Fig. 2, and 100 m was recovered during the purification process. 3 A portion of the process water (W) of / h was branched and passed through an arsenic removal device (400) as shown in FIG. 3 to remove arsenic in the process water.

[0099] Specifically, as shown in FIG. 3, a 10 m filter having an internal structure in which a first filter layer (11), an adsorbent layer (20) including an arsenic adsorbent based on iron hydroxide, and a second filter layer (12) are sequentially laminated 3 The process water (W) branched at different volume flow rates was passed through the arsenic removal device (400). At this time, the arsenic (As(V)) concentration of the process water before being supplied to the arsenic removal device was 1 ppb (1,000 ppt), and the temperature of the process water was room temperature. In addition, the arsenic concentration of the process water after passing through the arsenic removal device was measured, and the arsenic removal rate according to the spatial residence time (EBCT) of the process water passing through the arsenic removal device is shown in Fig. 6.

[0100] Referring to Figure 6, when the EBCT of the process water passing through the arsenic removal device is 10 minutes (i.e., the volume flow rate of the branched process water is 60 m 3 / h) The arsenic removal rate was approximately 63 wt%, and when the EBCT was 30 minutes (i.e., the volumetric flow rate of the branched process water was 20 m 3 / h) The arsenic removal rate was approximately 90 wt%, and when the EBCT was more than 1 hour (i.e., the volumetric flow rate of the branched process water was 10 m 3 / h) was found to remove more than 99 wt% of arsenic.

[0101] [Experimental Example]

[0102] When arsenic is introduced into the IPA process due to catalyst replacement, the arsenic concentration in the product begins to be detected at a level approximately 40 times higher than the management standard, and the arsenic concentration tends to decrease over time. In the case of process water such as Example 1, the flow rate is approximately 8 to 9 times larger than pure IPA due to the characteristics of the process, and since it circulates and is recycled within the process, most of the arsenic once concentrated within the process is concentrated within the process water, and only a portion of it is included in the IPA and eluted. Therefore, once a high concentration of arsenic is introduced into the process, it remains within the process for a long time.

[0103] Accordingly, in this experimental example, in order to confirm the effect of arsenic removal in a product depending on whether or not the arsenic removal process according to the present disclosure was introduced, arsenic was introduced into the IPA manufacturing process so that 40 times more arsenic was detected than the management standard, and the change in arsenic concentration in the IPA product over time was confirmed, and the results are shown in Table 1 and Fig. 7 below.

[0104] In Table 1 below, Comparative Experimental Example 1 is one in which the arsenic removal process according to the present disclosure was not performed, and Experimental Examples 1 to 6 are ones in which the arsenic removal process was performed as in Example 1.

[0105] Specifically, in Experimental Examples 1 to 6, a portion of the process water was branched and passed through arsenic removal devices of different sizes, and at this time, the branching ratio of the process water was changed as shown in Table 1 below, and the flow rate of the process water fed into each arsenic removal device was adjusted so that the EBCT of each experimental example was 1 hour, and the arsenic removal experiment was conducted. In addition, Experimental Example 7 was conducted under the same conditions as Experimental Example 6, except that the arsenic removal process was performed using two arsenic removal devices connected in parallel.

[0106] In addition, in Table 1 and Fig. 7 below, the “number of days required” is the period from the time arsenic was added until the arsenic concentration in the IPA product normalizes, i.e., the number of days required for the arsenic concentration in the product to reach 4,000% to 100% of the management standard, measured by the arsenic removal rate (weight %) of the process water. In addition, the “number of days shortened” is a comparison of the degree of shortening of the number of days required for Experimental Examples 1 to 7 based on the number of days required for Comparative Experimental Example 1.

[0107] Process moisture content (vol%) Process arsenic removal rate (%) Number of days required (Day) Number of days shortened (Day) Comparison Experimental example 1-030-Experimental example 111264Experimental example 222237Experimental example 333219Experimental example 4441911Experimental example 5551812Experimental example 610101317Experimental example 710 / 1020921

[0108] Referring to Table 1 and FIG. 7, in Comparative Experimental Example 1, which did not perform the arsenic removal process according to the present disclosure, the arsenic concentration decreased from 4,000% to 100% of the control standard over approximately one month. This means that the IPA produced over a period of 30 days did not meet the control standard and is therefore unsuitable as IPA used in semiconductor processes.

[0109] Meanwhile, Experimental Examples 1 to 7, which introduced the arsenic removal process according to the present disclosure, were able to shorten the period required from the time of arsenic introduction until the concentration of arsenic normalizes by removing arsenic from the process water. Furthermore, the higher the arsenic removal rate in the process water, the shorter the period required for the arsenic concentration in the product to normalize, and the shorter the period, the higher the production volume of high-quality products, which is advantageous from an economic perspective.

[0110] Furthermore, in Experimental Example 7, where two arsenic removal devices were connected in parallel to perform the arsenic removal process, the number of days required to determine the arsenic concentration in the product was not significantly reduced compared to Experimental Example 6, where a single arsenic removal device was used. Considering this, it is deemed necessary to appropriately design the process by comparing the cost incurred when adding an arsenic removal device with the benefit that can be gained from the increased product production equivalent to the number of days shortened by adding the device.

[0111] Although exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and those skilled in the art will understand that various changes and modifications are possible within the scope and spirit of the claims set forth below.

[0112] [Explanation of symbols]

[0113] 100: Reactor

[0114] 201: Absorption tower

[0115] 202: Gas Purification Unit

[0116] 301: Organic Removal Tower

[0117] 302: Water removal tower

[0118] 303: IPA separation unit

[0119] 400: Arsenic removal device

[0120] 11, 12: Filter layer

[0121] 20: Adsorbent layer

[0122] 30, 30a, 30b, 30c: Bulkhead

Claims

1. (S1) A step of supplying propylene monomer and reaction water as a feed stream to a reactor to produce a gaseous reaction product containing isopropyl alcohol; (S2) a step of purifying isopropyl alcohol from the above gas phase reaction product and recovering process water; and (S3) A step of passing the above process water through an arsenic removal device comprising a first filtration layer, an adsorbent layer, and a second filtration layer; and The above step (S3) comprises the process water sequentially passing through a first filtration layer, an adsorbent layer, and a second filtration layer inside the arsenic removal device, in a method for producing isopropyl alcohol.

2. In Paragraph 1, A method for producing isopropyl alcohol, comprising having the first filtration layer, the adsorbent layer, and the second filtration layer sequentially stacked inside the arsenic removal device.

3. In paragraph 1, A method for producing isopropyl alcohol, wherein the adsorbent layer is divided into first to n regions, and each of the first to n regions is filled with a first to n arsenic adsorbent.

4. In Paragraph 3, A method for producing isopropyl alcohol, comprising supplying the process water to one side of the first region when it passes through the adsorbent layer, passing sequentially from the first region to the nth region, and then discharging it in one direction selected from one side and the other side of the nth region.

5. In paragraph 3, A method for producing isopropyl alcohol, wherein n is an integer from 2 to 5.

6. In paragraph 1, A method for producing isopropyl alcohol, wherein the adsorbent layer comprises one or more arsenic adsorbents selected from iron hydroxide, activated alumina, titanium oxide, alpha iron oxide, gamma iron oxide, and ion-exchange resins.

7. In Paragraph 1, A method for producing isopropyl alcohol, wherein the first filtration layer and the second filtration layer each independently comprise one or more selected from activated carbon, sand, zeolite, silica gel, and mesh.

8. In paragraph 1, A method for producing isopropyl alcohol, wherein the space residence time of the process water passing through the above arsenic removal device is 10 minutes to 6 hours.

9. In paragraph 1, The above step (S3) comprises passing a portion of the process water through the arsenic removal device after branching the process water. A method for producing isopropyl alcohol.

10. In paragraph 9, A method for producing isopropyl alcohol, comprising a flow rate ratio (v / v) of the process water passing through the arsenic removal device of 1% to 20% based on the total volume flow rate of the process water.

11. In paragraph 1, A method for producing isopropyl alcohol, wherein the temperature of the process water is 20℃ to 150℃.

12. In Paragraph 1, A method for producing isopropyl alcohol, wherein the above gas phase reaction product comprises isopropyl alcohol, unreacted propylene, unreacted water, and by-products.

13. In paragraph 1, The above step (S2) is, (i) The gas phase reaction product is fed to an absorption tower and brought into contact with wash water to obtain an aqueous solution containing isopropyl alcohol, and (ii) supply the aqueous solution containing the isopropyl alcohol to a gas purification unit to separate an upper stream containing low-boiling point components from a lower stream containing isopropyl alcohol, water, and by-products, and (iii) The lower stream of the gas purification unit is supplied to an organic matter removal tower and brought into contact with washing water to separate it into a liquid phase containing isopropyl alcohol and water and a liquid phase containing organic matter, and (iv) A method for producing isopropyl alcohol, comprising supplying a liquid phase containing isopropyl alcohol and water to a water removal tower to separate the liquid phase into an upper stream containing isopropyl alcohol and a lower stream of water, and then purifying isopropyl alcohol from the upper stream and recovering the lower stream as process water.

14. In paragraph 13, A method for producing isopropyl alcohol, wherein the washing water used in the absorption tower and the organic matter removal tower is the process water recovered in step (S2).

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