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 purified isopropyl alcohol 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. 10-2024-0121957, filed September 7, 2024, and Korean Patent Application No. 10-2025-0101553, 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 from isopropyl alcohol.

[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] However, arsenic degrades the quality of IPA and therefore needs to be removed from the final product. Typically, IPA refining 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 refining unit, making complete removal through distillation difficult. Therefore, to produce high-quality isopropyl alcohol, the development of a technology capable of effectively removing arsenic from IPA is essential.

[0009] The problem to be solved in the present disclosure is to provide a method for continuously removing arsenic from purified isopropyl alcohol to obtain high-quality isopropyl alcohol 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 purified isopropyl alcohol 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 purified isopropyl alcohol through an arsenic removal device including a first filter layer, an adsorbent layer, and a second filter layer may include sequentially passing the purified isopropyl alcohol 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 improve the quality of IPA by continuously removing arsenic in purified isopropyl alcohol through adsorption.

[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 is a graph showing 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 product.

[0022] The terms or words used in the description and claims of the present disclosure should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present disclosure, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention 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 30.5 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, IPA undergoes a process in which it is condensed into a gas phase and purified, but some of the arsenic in the process water decomposes and sublimates within the distillation column, resulting in arsenic detection in the gaseous IPA stream. Therefore, distillation is difficult to completely remove arsenic, and the process water remains circulated with arsenic for a long period of time, resulting in detection within the product and a deterioration in the quality of the IPA.

[0038] Accordingly, in the present disclosure, it is intended to manufacture high-quality isopropyl alcohol by continuously removing arsenic present in IPA through adsorption in an isopropyl manufacturing process.

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

[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 water recovered from the bottom of the water removal tower is used as process water.

[0042] Figure 2 illustrates in more detail part A of Figure 1, which is a post-process tower. Referring to Figure 2, purified IPA that has passed through a water removal tower (302) and an IPA separation unit (303) is passed through an arsenic removal device (400) to remove arsenic before recovering the final product, thereby obtaining high-quality IPA.

[0043] The above arsenic removal device (400) can be appropriately designed and changed according to the flow rate of purified IPA. For example, the space residence time (EBCT) of the arsenic removal device can be designed to be 10 minutes or more, 30 minutes or more, or 1 hour or more and 3 hours or less, 4 hours or less, or 5 hours or less. When the above space residence time range is satisfied, 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 efficiency.

[0044] 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 inside.

[0045] In addition, although the arsenic removal device is depicted in a vertical direction in FIG. 3, the arsenic removal device may be positioned horizontally as needed. Accordingly, the purified IPA 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 discharged from the other side.

[0046] 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).

[0047] 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.

[0048] As illustrated in Fig. 3, the adsorbent layer (20) is provided to adsorb and remove trace amounts of arsenic contained in the purified IPA, and is located between the first filter layer (11) and the second filter layer (12). Arsenic adsorbents that can be used as the adsorbent layer (20) include, for example, iron hydroxide, activated alumina, titanium oxide, ion exchange resins, metal oxide-based adsorbents such as alpha iron oxide and gamma iron oxide, and ion exchange resins. The arsenic adsorbent may have different sizes depending on the shape and type. For example, the metal oxide-based adsorbent may be in the form of pellets or granules, and the size may range from 0.5 mm to 100 mm in diameter, but is not limited thereto. Additionally, the ion exchange resin may be of a gel or microporous type, and its size may be from 300 μm to 1,200 μm, but is not limited thereto.

[0049] In addition, the adsorbent layer (20) may be provided within the arsenic removal device (400) for 10 minutes or more, 30 minutes or more, or 1 hour or more and 3 hours or less, 4 hours or less, or 5 hours or less. By satisfying the above range, arsenic contained in the purified IPA can be sufficiently removed.

[0050] More specifically, based on 100 wt% of arsenic content contained in the isopropyl alcohol before passing through the arsenic removal device (400), the arsenic removal rate after passing through the arsenic removal device (400) can be satisfied as 20% or more, specifically 25 wt% to 95 wt%, and more specifically 30 wt% to 90 wt%.

[0051] In addition, the temperature of IPA passing through the arsenic removal device (400) may be 40°C to 150°C or 40°C to 60°C, and the temperature range at which arsenic can be removed may vary depending on the type of adsorbent.

[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 IPA passes through the adsorbent layer increases, so that the area and time for which IPA 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 partitioned into first to n-th regions, when IPA passes through the arsenic removal device (400), the IPA may be supplied to one side of the first region (1), sequentially pass through the first region to the n-th region, and then be discharged in one direction selected from one side and the other side of the n-th region. For example, when partitioned into an odd number of regions, the IPA may be discharged to the other side of the n-th region, and when partitioned into an even number of regions, the IPA may 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. The interior of the arsenic removal device (400) may be divided into two or more regions, preferably 2 to 5 regions, and more preferably 3 to 4 regions.

[0055] According to one embodiment, the first to nth regions can be partitioned by first to nth packings. The first to nth packings have a structure in which a plurality of packing members are radially arranged to form an overall cylindrical shape, and each packing member can have a cross-section formed in a sector shape or a triangular sector shape. Accordingly, the first to nth regions can be detachable in a packing manner, thereby allowing the adsorbent to be replaced as needed. At this time, the first to nth packings can be filled with the same or different types of adsorbents, respectively.

[0056] In addition, a flow path with at least one side open may be provided between adjacent regions among the first to n-th regions so that IPA can move between the two regions. However, even if the first region (i.e., the first packing) where the IPA inlet is located and the n-th region (i.e., the n-th packing) where the IPA outlet is located are adjacent to each other, there should not be an open flow path between them. More specifically, a flow path open in the other side (C, E) direction may be formed between an odd-numbered packing (e.g., the first packing) and an even-numbered packing (e.g., the second packing), and a flow path open in the other side (B, D) direction may be formed between an even-numbered packing (e.g., the second packing) and an odd-numbered packing (e.g., the third packing). Through this structure, the IPA injected into the adsorbent layer can be discharged after contacting all of the first to n-th adsorbents in the first to n-th packings.

[0057] Meanwhile, in order to prevent the adsorbent from leaking out of the arsenic removal device, a first filter layer (11) may be provided on the IPA inlet side of the first region (i.e., the first packing) through which IPA passes first among the regions partitioned by the packing method, and a second filter layer (12) may be provided on the IPA outlet side of the nth region (i.e., the nth packing) through which IPA 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.

[0058] FIG. 4 illustrates a structure in which an arsenic removal device (400) according to one embodiment is provided with first to third packings (1, 2, 3) as adsorbent layers (20). The lower drawing is a longitudinal cross-sectional view of the device, the upper left drawing is a cross-sectional view of one side (B) of the device, and the upper 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 in a packing manner is odd, it is preferable that when IPA is introduced into one side of the arsenic removal device, it passes through the adsorbent in each region and is then 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 packing (1), a second packing (2), and a third packing (3), IPA can be introduced into one side of the first packing (1), pass through the second packing (2), and then be discharged from the other side of the third packing (3).

[0061] More specifically, the surface (dotted line) where the second packing (2) and the third packing (3) come into contact may have a structure in which one side (B) is open, and the other side (C) of the surface (dotted line) where the first packing (1) and the second packing (2) come into contact may be open. In addition, one side (B) of the first packing (1) may have a structure in which a pipe is connected or open so that IPA can be injected, and the other side (C) of the third packing (3) may have a structure in which a pipe is connected or open so that IPA can be discharged. Since the above arsenic removal device (400) has such a structure, IPA supplied from one side (B) can sequentially move in the direction of "one side of the first packing (1) → the other side of the first packing (1) → the other side of the second packing (2) → one side of the second packing (2) → one side of the third packing (3) → the other side of the third packing (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 the arsenic removal device (400) according to one embodiment is provided with first to fourth packings (1, 2, 3, 4) as adsorbent layers (20), wherein the lower drawing is a longitudinal cross-sectional view of the device, the upper left drawing is a cross-sectional view of one side (D) of the device, and the upper 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 in a packing manner is an even number, when IPA is injected into one side of the arsenic removal device, it can pass through the arsenic adsorbent in each region and then be discharged in the same direction as the IPA injection direction.

[0064] Specifically, referring to FIG. 5, when the arsenic removal device (400) according to one embodiment is divided into a first packing (1), a second packing (2), a third packing (3), and a fourth packing (4), IPA can be introduced into one side of the first packing (1), pass through the second packing (2) and the third packing (3), and then be discharged through the fourth packing (4).

[0065] More specifically, the surface (dotted line) where the second packing (2) and the third packing (3) come into contact may have an open side (D), and the surface (dotted line) where the first packing (1) and the second packing (2) come into contact and the surface (dotted line) where the third packing (3) and the fourth packing (4) come into contact may have an open side (E). In addition, one side (D) of the first packing (1) and the fourth packing (4) may have a structure in which a pipe is connected or open so that IPA can be independently injected or discharged. Since the above arsenic removal device (400) has such a structure, IPA supplied from one side (D) can sequentially move in the following order: “one side of the first packing (1) → the other side of the first packing (1) → the other side of the second packing (2) → one side of the second packing (2) → one side of the third packing (3) → the other side of the third packing (3) → the other side of the fourth packing (4) → one side of the fourth packing (4)” and can finally be discharged in the direction of one side (D) of the arsenic removal device (400).

[0066] Meanwhile, a portion of the above process water (W) is transferred to the absorption tower (201) and the organic matter removal tower (301) and used as absorption water and washing water, respectively, and the remainder is discharged as waste water.

[0067] Reaction water, which is usually used as a raw material for manufacturing isopropyl alcohol, is supplied to the reactor for gas phase reaction with propylene monomer.

[0068] 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 products pass through the subsequent process, such as the absorption tower (201), organic matter removal tower (301), and water removal tower (302). Referring to Fig. 1, the process water (W) recovered in the water removal tower (302) is recycled for washing the previous process tower (e.g., the absorption tower (201) and organic matter removal tower (301)).

[0069] Additionally, 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 wash water for the organic matter removal tower (301). Additionally, some of the cooled process water may be treated as wastewater, and if necessary, after passing through an additional cooler, the water may be branched so that some of the water may be used to control the temperature 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), some of which can be recycled as wash water and / or absorption 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 / cm 2It 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 the IPA separation unit (303) including the IPA purification tower and the solvent recovery tower and the arsenic removal device (400) to recover IPA.

[0092] For example, when an organic solvent (e.g., cyclohexane, benzene, etc.) is injected as an azeotrope into the IPA purification tower of the IPA separation unit (303), the azeotrope of isopropyl alcohol and water is broken, so that highly purified isopropyl alcohol can be obtained at the bottom. At this time, the bottom discharge stream of the IPA purification tower containing the purified IPA can be passed through the arsenic removal device (400) as described above to remove arsenic. In addition, the upper portion of the IPA purification tower can be separated into a stream containing the azeotrope and water, 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 FIGS. 1 and 2, and at this time, the purified isopropyl alcohol (IPA) stream recovered in the purification process was passed through an arsenic removal device (400) as shown in FIG. 3 to remove arsenic in the IPA.

[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 10 m of IPA stream with arsenic (As(V)) concentration of 100 ppt in a volumetric arsenic removal device (400) 3 / h was passed under room temperature and pressure conditions. That is, when the EBCT was 1 hour, the arsenic concentration of IPA was measured after passing through the arsenic removal device, and the arsenic removal rate was 45 wt%.

[0100] In relation to this, Fig. 6 is a graph showing the arsenic removal rate according to the spatial residence time (EBCT) of IPA passing through the arsenic removal device.

[0101] Referring to Fig. 6, 10 m 3When the EBCT of IPA passing through the arsenic removal device having a volume of 30 minutes, the arsenic removal rate was approximately 45 wt%, when the EBCT was 1 hour, the arsenic removal rate was approximately 50 wt%, and when the EBCT was 2 hours or more, it was found that more than 80 wt% of arsenic was removed. For reference, the fact that the arsenic removal rates were all 90% when the EBCT was 3 to 5 hours in the above Fig. 6 is because it exceeded the measurement limit.

[0102] For reference, using the same specification arsenic removal device, the volume flow rate of purified IPA is 10 m 3 Assuming a fixed process of / h, 10 m 3 When the entire IPA stream of / h is fed into the arsenic removal device, the arsenic removal rate is 50 wt%, which is 5 m 3 / h You can get an arsenic-free IPA stream.

[0103] On the other hand, the IPA stream is partially branched to 5 m 3 The IPA stream of / h does not pass through the arsenic removal unit, and the remaining 5 m 3 If only the IPA stream of / h is fed into the arsenic removal device, the remaining 5 m 3 Only 80 wt% of arsenic was removed from the IPA stream at / h, and some 5 m 3 / h of IPA stream is not arsenic removed, totaling 4 m 3 Only an IPA stream with arsenic removed of / h can be obtained. Therefore, even if the same device is used, the arsenic removal efficiency may vary depending on the flow rate of the IPA stream fed into the device.

[0104] [Experimental Example]

[0105] When arsenic enters 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. Due to the nature of the IPA manufacturing process, the flow rate of the circulating water is approximately 8 to 9 times greater than the purified IPA stream, and it is recycled while circulating within the process. Therefore, most of the arsenic once concentrated within the process is concentrated within the process water, and only a portion of it is dissolved into the IPA. Therefore, once a high concentration of arsenic is introduced into the process, it remains within the process for a long time.

[0106] Introducing an arsenic removal process into a purified IPA stream with a relatively low flow rate can increase the arsenic removal rate while reducing the size of the device and the amount of adsorbent used. Therefore, in this experimental example, to determine the effect of arsenic removal in the product depending on whether or not the arsenic removal process according to the present disclosure was introduced, arsenic was added to 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 determined. The results are shown in Table 1 and Fig. 7 below.

[0107] In Table 1 below, Comparative Experimental Example 1 does not perform the arsenic removal process according to the present disclosure, and Experimental Examples 1 to 6 perform the arsenic removal process according to the present disclosure as in Example 1. Specifically, Experimental Examples 1 to 6 performed arsenic removal experiments using arsenic removal devices of the same size, but by controlling the flow rate of IPA to have different spatial residence times as shown in Table 1 below.

[0108] In addition, in Table 1 and Fig. 7 below, the “number of days required” is the period from the time arsenic is introduced into the process 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 IPA. In addition, the “number of days shortened” is the degree of shortening in the number of days required to normalize the arsenic concentration in Experimental Examples 1 to 6, calculated based on the number of days required for Comparative Experimental Example 1.

[0109] Spatial residence time (h)Arsenic removal rate (%)Days required (Days shortened)Comparison Experimental example 1-030-Experimental example 10.6530300Experimental example 20.8240300Experimental example 31.560291Experimental example 4280273Experimental example 5390246Experimental example 65 (>3h)951515

[0110] 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.

[0111] Meanwhile, Experimental Examples 3 to 6, which introduced the arsenic removal process according to the present disclosure, were able to shorten the period required from the time arsenic was added to the normalization of the arsenic concentration in the product by removing arsenic in the process water. However, in the case of Experimental Examples 1 and 2, where the arsenic removal rate in the product was 40% or less, the required period was not shortened. In addition, the higher the arsenic removal rate in IPA, the shorter the period required for the arsenic concentration to normalize, and the production volume of high-quality products can be secured by the number of shortened periods, which is advantageous from an economic perspective.

[0112] Furthermore, under process conditions with a constant flow rate of IPA produced, a larger arsenic removal device and greater adsorbent usage can improve arsenic removal rates. Considering this, it is necessary to appropriately design the process by comparing the cost of increasing the volume of the arsenic removal device to the benefits gained from increased product production resulting from the improved arsenic removal rate.

[0113] 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.

[0114] [Explanation of symbols]

[0115] 100: Reactor

[0116] 201: Absorption tower

[0117] 202: Gas Purification Unit

[0118] 301: Organic Removal Tower

[0119] 302: Water removal tower

[0120] 303: IPA separation unit

[0121] 400: Arsenic removal device

[0122] 11, 12: Filter layer

[0123] 20: Adsorbent layer

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 including isopropyl alcohol; (S2) a step of purifying isopropyl alcohol from the above-mentioned gaseous reaction product and recovering process water; and (S3) a step of passing the purified isopropyl alcohol through an arsenic removal device including a first filter layer, an adsorbent layer, and a second filter layer; The above step (S3) is a method for producing isopropyl alcohol, comprising sequentially passing the purified isopropyl alcohol through a first filter layer, an adsorbent layer, and a second filter layer inside the arsenic removal device.

2. In paragraph 1, A method for producing isopropyl alcohol, comprising sequentially stacking the first filter layer, the adsorbent layer, and the second filter layer 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-th regions, and first to n-th adsorbents are filled in each of the first to n-th regions.

4. In paragraph 3, A method for producing isopropyl alcohol, comprising: when the purified isopropyl alcohol passes through the adsorbent layer, it is supplied to one side of the first region, sequentially passes from the first region to the n-th region, and then discharged in one direction selected from one side and the other side of the n-th 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 at least one arsenic adsorbent selected from iron hydroxide, activated alumina, titanium oxide, alpha iron oxide, gamma iron oxide, and ion exchange resin.

7. In paragraph 1, A method for producing isopropyl alcohol, wherein the first filter layer and the second filter layer each independently include at least one selected from activated carbon, sand, zeolite, silica gel, and mesh.

8. In paragraph 1, A method for producing isopropyl alcohol, wherein the spatial residence time of the above arsenic removal device is 10 minutes to 5 hours.

9. In paragraph 1, A method for producing isopropyl alcohol, wherein the temperature of the isopropyl alcohol passing through the above arsenic removal device is 30°C to 120°C.

10. In paragraph 1, A method for producing isopropyl alcohol, wherein the arsenic removal rate after passing through the arsenic removal device is 30 wt% or more, based on 100 wt% of the arsenic content contained in the isopropyl alcohol before passing through the arsenic removal device.

11. In paragraph 1, A method for producing isopropyl alcohol, wherein the above-mentioned gaseous reaction product comprises isopropyl alcohol, unreacted propylene, unreacted water and by-products.

12. In paragraph 1, The above step (S2) is, (i) supplying the gaseous reaction product to an absorption tower and contacting it with washing water to obtain an aqueous solution containing isopropyl alcohol; (ii) supplying the aqueous solution containing the above isopropyl alcohol to a gas purification unit to separate an upper stream containing low-boiling-point components and a lower stream containing isopropyl alcohol, water, and by-products; (iii) The bottom stream of the gas purification unit is supplied to an organic matter removal tower and brought into contact with wash water to separate the liquid phase containing isopropyl alcohol and water and the liquid phase containing organic matter, (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.

13. In paragraph 12, A method for producing isopropyl alcohol, wherein the wash water used in the above absorption tower and the above organic matter removal tower is the process water recovered in the above step (S2).

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