Method for preparing isopropyl alcohol

Abstract

The present invention relates to a method for preparing isopropyl alcohol, the method comprising the steps of: reacting by supplying a feed stream comprising propylene monomers and water to a reaction unit so as to produce a reaction product comprising the isopropyl alcohol, the propylene monomers, and the water; supplying, to an absorption tower of a purification unit, each of a first stream comprising a gaseous reaction product and a second stream comprising a liquid reaction product, which are discharged from the reaction unit; and discharging a third stream comprising the propylene monomers from the upper part of the absorption tower and circulating same to the reaction unit, and discharging a liquid fourth stream comprising the water and the isopropyl alcohol from the lower part of the absorption tower and supplying same to an isopropyl alcohol purification unit, wherein the purification unit comprises one or more heat exchangers, and when circulating the third stream to the reaction unit, the third stream is transferred after being converted from a gas phase to a liquid phase through the one or more heat exchangers provided in the purification unit.

Description

Method for producing isopropyl alcohol

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0126458, filed September 21, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for producing isopropyl alcohol, and more particularly, to a method for separating isopropyl alcohol from a reaction product of an isopropyl alcohol production process and effectively recovering unreacted substances, thereby reducing energy usage by introducing a liquefaction process when recovering unreacted substances.

[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] The process for manufacturing isopropyl alcohol uses, for example, propylene and water as raw materials. The propylene and water react to produce isopropyl alcohol. The reaction product of the isopropyl alcohol manufacturing process includes isopropyl alcohol, unreacted propylene monomer, and unreacted water. The isopropyl alcohol is separated and recovered from the reaction product of the isopropyl alcohol manufacturing process, and the unreacted propylene monomer is recovered and reused in the isopropyl alcohol manufacturing process.

[0007] In this regard, an absorption tower is generally used to separate isopropyl alcohol and unreacted propylene monomer from the reaction product of the isopropyl alcohol manufacturing process. Specifically, the isopropyl alcohol manufacturing process is performed through a gas-phase reaction, wherein the generated gas-phase reaction product is supplied to the bottom of the absorption tower, and the isopropyl alcohol in the reaction product is dissolved using water as a solvent and separated from the bottom of the absorption tower, and the gas-phase stream containing propylene monomer is separated from the top and recycled to the reactor. At this time, in order to recycle the gas-phase stream containing propylene monomer to the reactor, the gas-phase stream must be compressed to high pressure using an additional device such as a compressor, and since the gas-phase stream has a large volumetric flow rate, the use of large-diameter pipes is essential. However, the high-pressure compression process for transporting the gas-phase stream is difficult to operate and maintain, and consumes a lot of power, resulting in high energy consumption, which increases facility maintenance and energy costs.

[0008] Therefore, in an isopropyl alcohol manufacturing process, a method is required to improve the efficiency of a process for recycling an absorption tower top discharge stream containing unreacted propylene monomer in the gas phase to a reactor, thereby securing economic feasibility and realizing energy savings.

[0009] The problem to be solved in the present invention is to provide a method for improving circulation efficiency, securing economic feasibility, and saving energy in a process of recycling an absorption tower top discharge stream containing unreacted propylene monomer in the gas phase during an isopropyl alcohol manufacturing process to a reactor in order to solve the problem mentioned in the background technology of the above invention.

[0010] However, the problems that the present invention seeks to solve 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 invention for solving the above problem, the present invention provides a method for producing isopropyl alcohol, including the steps of: supplying a feed stream containing propylene monomer and water to a reaction unit to react and producing a reaction product containing isopropyl alcohol, propylene monomer, and water; supplying a first stream containing a gaseous reaction product discharged from the reaction unit and a second stream containing a liquid reaction product, respectively, to an absorption tower of a purification unit; and circulating a third stream containing a gaseous reaction product discharged from an upper portion of the absorption tower to the reaction unit, and supplying a fourth stream containing water and isopropyl alcohol discharged from a lower portion of the absorption tower to an isopropyl alcohol purification unit.

[0012] In addition, in the method for producing isopropyl alcohol according to the present invention, the purification unit may include one or more heat exchangers, and when circulating the third stream to the reaction unit, it may include converting it from a gaseous phase to a liquid phase and transporting it through one or more heat exchangers provided in the purification unit.

[0013] According to the method for producing isopropyl alcohol of the present invention, a reaction product in an isopropyl alcohol production process is supplied to an absorption tower to separate unreacted propylene monomer and isopropyl alcohol, and a gaseous stream containing unreacted propylene monomer discharged from the upper portion of the absorption tower is liquefied and circulated to a reaction section, thereby effectively reducing the volumetric flow rate of the stream, thereby improving the circulation efficiency of unreacted monomer within the process. Furthermore, by providing a plurality of heat exchangers at the rear end of the absorption tower to induce heat exchange between streams, heat recovery can be maximized while reducing the amount of refrigerant used.

[0014] The effects that can be obtained from this invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art to which the present invention pertains from the description below.

[0015] Figure 1 is a process flow diagram of a method for producing isopropyl alcohol according to one embodiment of the present invention.

[0016] Figure 2 is a process flow diagram of a method for manufacturing isopropyl alcohol according to one embodiment of the present invention.

[0017] Figure 3 is a process flow diagram of a method for manufacturing isopropyl alcohol according to a comparative example.

[0018] The terms or words used in the description and claims of the present invention 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 invention, 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.

[0019] In connection with the description of the drawings, similar reference numerals may be used for similar or related components.

[0020] 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.

[0021] 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.

[0022] The term “and / or” includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0023] 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).

[0024] In addition, terms such as 'front', 'rear', 'top', 'bottom', 'side', 'left', 'right', 'upper', and 'lower' used in this application are defined based on the drawings, and the shape and position of each component are not limited by these terms.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] In addition, the terms "about", "substantially", etc. used herein 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 the present invention.

[0029] The term "stream" as used herein may refer to the flow of fluid within a process, or may 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.

[0030] 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).

[0031] Additionally, “pressure” as referred to herein means gauge (g) pressure measured based on atmospheric pressure.

[0032] One embodiment of the present invention relates to a method for producing isopropyl alcohol (IPA). Hereinafter, the method for producing isopropyl alcohol of the present invention will be described in detail with reference to the drawings.

[0033] According to the present invention, a method for producing isopropyl alcohol is provided. The method for producing isopropyl alcohol according to the present invention comprises the steps of generating a reaction product in a reaction unit (100), supplying the reaction product to an absorption tower (210), and recovering unreacted monomers in the reaction product from the absorption tower (210) to the reaction unit (100).

[0034] Figures 1 and 2 are process flow diagrams of a method for producing isopropyl alcohol according to one embodiment of the present invention, respectively.

[0035] The above isopropyl alcohol can be produced by a vapor phase reaction of propylene monomer and water. Specifically, a feed stream (1) containing propylene monomer and water is supplied to a reaction unit (100), and the reaction product produced in the reaction unit (100) can include isopropyl alcohol, unreacted propylene monomer, and unreacted water. At this time, isopropyl alcohol is separated and recovered from the reaction product, and the unreacted propylene monomer is recovered and reused in the isopropyl alcohol production process.

[0036] The method for producing isopropyl alcohol according to the present invention first supplies a feed stream (1) containing propylene monomer and water to a reaction unit (100) to react and produce a reaction product containing isopropyl alcohol. The reaction product may further contain unreacted propylene monomer, water, and side products.

[0037] According to one embodiment of the present invention, the molar ratio (water / propylene monomer) of water and propylene monomer supplied to the reaction unit (100) may be 0.3 to 0.5, specifically 0.35 to 0.5, and more specifically 0.35 to 0.45. When the molar ratio in the stream supplied to the reaction unit (100) is low, the conversion rate into isopropyl alcohol may increase, but this may increase the rate of by-product production. That is, when the molar ratio increases, the conversion rate into isopropyl alcohol decreases, but high selectivity may be obtained.

[0038] According to one embodiment of the present invention, a feed stream (1) containing the propylene monomer and water is supplied to a reactor (110) of a reaction unit (100), and a gas phase reaction is performed in the reactor (110), thereby obtaining unreacted propylene monomer and water, a reaction product, isopropyl alcohol, and a side product. By producing isopropyl alcohol through a gas phase reaction in the reactor (110), the amount of byproducts produced by the side reaction can be reduced.

[0039] According to one embodiment of the present invention, the reactor (110) can be operated under optimal conditions for efficiently producing isopropyl alcohol through a gas phase reaction of propylene monomer and water. For example, the operating pressure of the reactor (110) is about 30 kg / cm 2 ·G to 50 kg / cm 2 ·G, preferably 35 kg / cm 2 ·G to 50 kg / cm 2 ·G, more preferably 35 kg / cm 2 ·G to 45 kg / cm 2·G may be used, and the operating temperature may be about 180°C to 220°C, preferably 185°C to 220°C, and more preferably 190°C to 215°C. By operating the reactor at the pressure and temperature in the above range, isopropyl alcohol can be effectively produced through a gas phase reaction using propylene monomer and water.

[0040] Meanwhile, the feed stream (1) containing propylene monomer and water may be supplied to the reactor (110) after being additionally heated through a heating means (121). The heating means (121) may be located at the front end of the reactor (110) and may be used as a heat source for the isopropyl alcohol production reaction. More specifically, the temperature of the feed stream may be supplied to the reactor through the heating means according to the reactor inlet temperature conditions. For example, the heating means (121) may be a heater that transfers heat to the feed stream (2) by passing high-temperature / high-pressure steam, hot water, or heat transfer fluid through a jacket, but there is no particular limitation thereto.

[0041] By causing a gaseous reaction between propylene monomer and water in the reactor (110), a gaseous reaction product (3) can be discharged from the reactor (110). At this time, the temperature of the gaseous reaction product (3) discharged from the reactor (110) can be, for example, 200°C to 220°C, 205°C to 220°C, or 205°C to 215°C.

[0042] The above reaction unit (100) may further include one or more heat exchangers (120). Referring to FIG. 1, the feed stream (1) may be supplied to the reactor (110) after passing through the heat exchanger (120) provided in the reaction unit (100).

[0043] According to one embodiment of the present invention, the gaseous reaction product discharged from the reactor (110) may pass through one or more heat exchangers (120), some of which may be condensed into a liquid reaction product, and the remainder may exist as a gaseous reaction product. As an example, the gaseous reaction product discharged from the reactor (110) may be separated into a first stream (4) including a gaseous reaction product and a second stream (5) including a liquid reaction product while passing through a heat exchanger (120) of a reaction unit. At this time, the first stream (4) and the second stream (5) may be separated and discharged through a separate pipe formed in the heat exchanger (120) of the reaction unit, or may be separated through a gas-liquid separation device installed at the rear end of the heat exchanger (120) of the reaction unit.

[0044] According to one embodiment of the present invention, the gaseous reaction product (3) discharged from the reactor (110) can exchange heat with the feed stream (14) supplied to the reactor (110) in one or more heat exchangers (120). Here, the feed stream (14) that exchanges heat with the reaction product (3) in the heat exchanger (120) acts as a cooling medium, and more specifically, in addition to the feed stream (1) including fresh raw materials, it can be a mixed stream (14) further including a recycle stream (11, 13) of unreacted raw materials to be described later. Specifically, the gaseous reaction product (3) discharged from the reactor (110) can be partially condensed while passing through one or more heat exchangers (120), and the feed stream (14) can be heated while passing through one or more heat exchangers (120) before being supplied to the reactor (110). At this time, the temperature of the feed stream (1) before passing through the one or more heat exchangers (120) may be, for example, 90°C to 130°C, specifically 100°C to 120°C, and more specifically 105°C to 115°C. In addition, the temperature of the feed stream (2) after passing through the one or more heat exchangers (120) may be, for example, 160°C to 180°C, specifically 165°C to 175°C. Meanwhile, the temperatures of the first stream (4) and the second stream (5) of the gaseous reaction product (3) discharged from the reactor (110) that has passed through the one or more heat exchangers (120) may be, for example, 110°C to 130°C, specifically 115°C to 125°C.

[0045] More specifically, a heat exchanger having a large shell diameter and a large number of tubes can be used as the heat exchanger (120) of the reaction section. For example, the shell diameter of the reaction section heat exchanger can be 700 mm to 900 mm, preferably 750 mm to 850 mm, and the number of tubes of the reaction section heat exchanger can be 600 to 800, preferably 650 to 750. By satisfying the shell diameter and the number of tubes, the internal cross-sectional area of ​​the heat exchanger (120) is increased, thereby improving the heat transfer area, and thus maximizing the heat recovery performance for the gaseous reaction product (3) discharged from the reactor, thereby increasing the heat exchange rate.

[0046] In this way, by heat-exchanging the gaseous reaction product stream (3) discharged from the reactor (110) with the mixed stream (14) of the recycle streams (11, 13) and the feed stream (1) flowing into the reaction unit (100) described later, the gaseous reaction product discharged from the reactor (110) can be separated into a first stream (4) containing the gaseous reaction product and a second stream (5) containing the liquid reaction product, and at the same time, the feed stream can be preheated and supplied to the reactor (110). Here, the first recycle stream (11) flowing into the reaction unit can be a gaseous stream, the second recycle stream (13) and the feed stream (1) flowing into the reaction unit can be liquid streams, and the mixed stream (14) in which these are mixed can be a gas-liquid mixed stream. Through this, energy for supplying and heating the feed stream to the reactor (110) can be saved, and the temperature and composition of the first stream (4) and the second stream (5) can be controlled to increase the separation efficiency in the subsequent separation process using the absorption tower.

[0047] According to one embodiment of the present invention, the first stream (4) may include 85 to 95 wt% of propylene monomer, 4 to 8 wt% of isopropyl alcohol, and 1 to 5 wt% of water. Specifically, the first stream (4) contains a very high content of propylene monomer, and very small amounts of isopropyl alcohol and water.

[0048] In addition, the second stream (5) may include 0.5 to 5 wt% of propylene monomer, 5 to 15 wt% of isopropyl alcohol, and 80 to 90 wt% of water. Specifically, the second stream (5) has a very low content of propylene monomer and a very high content of water. At this time, the content of isopropyl alcohol included in the second stream (5) may be higher than the content of isopropyl alcohol included in the first stream (4).

[0049] According to one embodiment of the present invention, the flow rate ratio of the first stream (4) to the flow rate of the second stream (5) discharged from the reaction unit (100) may be 1:5 to 1:15, 1:7 to 1:12, or 1:8 to 1:10. By cooling the gaseous reaction product stream discharged from the reactor (110) to a temperature of 110°C to 130°C, the flow rate ratio of the first stream (4) to the flow rate of the second stream (5) may be controlled to 1:5 to 1:15. Here, the 'flow rate' may mean the flow of weight per unit time. As a specific example, the unit of the flow rate may be ton / hr.

[0050] A first stream (4) containing a gaseous reaction product discharged from the above reaction unit (100) and a second stream (5) containing a liquid reaction product are each supplied to an absorption tower (210) of a purification unit (200). More specifically, the gaseous reaction product stream (3) discharged from the reactor (110) is separated into a first stream (4) containing a gaseous reaction product and a second stream (5) containing a liquid reaction product while passing through one or more heat exchangers (120) provided in the reaction unit as described above, and can be supplied to the lower side of the absorption tower (210).

[0051] In addition, the purification unit (200) may include a heat exchanger (214) at the front end of the absorption tower (210). When supplying the first stream (4) to the absorption tower (210), the first stream (4) including the gaseous reaction product may be partially condensed through the first heat exchanger (214) provided in the purification unit (200) and supplied to the absorption tower (210) as a gas-liquid mixed phase. For example, the heat exchanger (214) may condense the first stream (4) by using a separate refrigerant or by heat-exchanging with a stream within the process. For example, the first stream (4) may be cooled by heat-exchanging with a stream (9, 9b) in the first heat exchanger (214) in which the upper discharge stream of the absorption tower, which will be described later, is liquefied and converted into a liquid phase or a gas-liquid mixed phase.

[0052] According to one embodiment of the present invention, the total number of stages of the absorption tower (210) may be 10 to 30 stages, specifically 15 to 30 stages, and more specifically 15 to 25 stages. For example, when the total number of stages of the absorption tower (210) is 10 stages, the first stream (4) and the second stream (5) may be supplied to stage 10 of the absorption tower (210).

[0053] According to one embodiment of the present invention, the reaction product supplied from the reaction unit (100) is supplied to an absorption tower (210), and a bottom discharge stream (6) containing isopropyl alcohol and an upper discharge stream (7) containing unreacted propylene monomer can be separated from the absorption tower (210). More specifically, the reaction product is supplied to the bottom of the absorption tower (210), and isopropyl alcohol in the reaction product is dissolved using water as a solvent and separated into the bottom of the absorption tower (210), and a stream containing unreacted propylene monomer can be separated into the top.

[0054] The solvent used in the above absorption tower (210) may be, for example, water. By using water, which is a component used in the reaction, as the solvent, a separate device for separating the solvent at the subsequent stage is not required.

[0055] The flow rate of the solvent supplied to the absorption tower (210) may be 20% to 60%, specifically 25% to 55%, and more specifically 30% to 50% of the total flow rate of the reaction product supplied to the absorption tower (210). By supplying the solvent at a flow rate within the above range, the absorption capacity of the isopropyl alcohol contained in the reaction product supplied to the absorption tower (210) can be improved, while at the same time, the energy cost for solvent recovery at the subsequent stage can be prevented from increasing excessively.

[0056] According to one embodiment of the present invention, the operating pressure of the absorption tower (210) is 20 kg / cm 2 ·G to 40 kg / cm 2 ·G, specifically 25 kg / cm 2 ·G to 40 kg / cm 2 ·G, more specifically 25 kg / cm 2 ·G to 35 kg / cm 2·G may be used, and the operating temperature may be 80°C to 110°C, specifically 90°C to 110°C, and more specifically 90°C to 100°C. By operating the absorption tower (210) at the above range of pressure and temperature, an upper discharge stream containing unreacted propylene monomer and a lower discharge stream containing isopropyl alcohol can be effectively separated.

[0057] According to one embodiment of the present invention, the third gaseous stream (7) containing propylene monomer discharged from the upper portion of the absorption tower (210) can be circulated to the reaction unit (100). At this time, the temperature of the third gaseous stream (7) can be 85°C to 105°C, specifically 90°C to 100°C.

[0058] FIG. 3 is a process flow diagram of a method for manufacturing isopropyl alcohol according to a comparative example. The isopropyl alcohol manufacturing process is performed through a gas phase reaction. At this time, the gas phase reaction product generated is supplied to the bottom of an absorption tower (210), and isopropyl alcohol in the reaction product is dissolved using water as a solvent and separated into a bottom discharge stream (6) of the absorption tower, and a gas phase stream containing propylene monomer is separated into an upper discharge stream (7) of the absorption tower and recycled to a reactor (110). At this time, in general, in order to recycle the gas phase upper discharge stream (7) containing propylene monomer to the reactor (110), the gas phase stream must be compressed to a high pressure using a compressor (213), as shown in FIG. 3, because the volumetric flow rate of the gas phase stream is large. However, even with high-pressure compression, there is a limit to reducing the volumetric flow rate of the gas phase stream, so the use of a pipe with a large internal diameter is essentially required. In addition, the high-pressure compression process for transporting gaseous streams is difficult to operate and maintain, and consumes a lot of power, resulting in increased equipment maintenance costs and energy costs.

[0059] In order to solve the above problem, in the present invention, in the isopropyl alcohol manufacturing process, in particular, the stream (7) discharged as a gas from the upper part of the absorption tower (210) is liquefied and transported through one or more heat exchangers (211, 211a, 211b), thereby effectively reducing the volumetric flow rate and thereby improving the circulation efficiency of unreacted monomers within the process.

[0060] According to one embodiment of the present invention, the purification unit (200) is provided with one or more heat exchangers (211, 211a, 211b) at the rear end of the third stream (7) discharged from the upper portion of the absorption tower (210). Accordingly, when the third stream (7) is circulated to the reaction unit (100), it can be converted from a gaseous phase to a liquid phase and transported through one or more heat exchangers (211a, 211b) provided in the purification unit (200). For example, the heat exchangers (211, 211a, 211b) provided in the purification unit can liquefy the gaseous third stream (7) by using a separate refrigerant or by heat exchange with a stream within the process. In addition, by liquefying the third stream (7), unreacted propylene monomer can be circulated to the reaction unit (100) using a pump (212), and the pipe size can be reduced due to a decrease in volumetric flow rate.

[0061] As illustrated in Fig. 1, when a heat exchanger (211) is provided at the rear end of the absorption tower (210), the liquid conversion of the third stream (7) can be performed, for example, by condensing the third stream (7) discharged from the upper portion of the absorption tower (210) using a separate refrigerant in the heat exchanger (211) provided in the purification unit (200). At this time, the condensed third stream (8) can be a liquid stream, and the temperature of the condensed third stream (8) can be, for example, 50°C to 75°C, and specifically, 60°C to 70°C. In addition, the liquid third stream (8) can be compressed through a pump (212), and the compressed liquid stream (9) can be supplied to the first heat exchanger (214).

[0062] As illustrated in Fig. 2, when two heat exchangers (211a, 211b) are provided at the rear end of the absorption tower (210), the liquid phase conversion of the third stream (7) can be performed, for example, by first condensing the third stream (7) discharged from the upper portion of the absorption tower (210) through the second heat exchanger (211b) provided in the purification unit (200), and then secondarily condensing the first condensed third stream (8a) through the third heat exchanger (211a) provided in the purification unit (200). At this time, the first condensed third stream (8a) may be a gas-liquid mixed phase stream, and the second condensed third stream (8b) may be a liquid phase stream. For example, the temperature of the first condensed third stream (8a) may be 70° C. to 90° C., specifically 75° C. to 85° C., and the temperature of the second condensed third stream (8b) may be 50° C. to 75° C., specifically 60° C. to 70° C. In this way, when the gaseous third stream (7) is liquefied using two heat exchangers (211a, 211b), there is an advantage of not only reducing the amount of refrigerant used in the heat exchangers but also maximizing heat recovery.

[0063] Referring to FIG. 2, for example, a third stream (7) in the gas phase can be first condensed into a gas-liquid mixed phase by heat exchange with a third stream (9) in the second condensed liquid phase through a second heat exchanger (211b), and the first condensed third stream (8a) in the gas-liquid mixed phase can be secondarily condensed into a liquid phase using a separate refrigerant in the third heat exchanger (211a). In addition, the stream (8b) liquefied by the second condensation can be compressed through a pump (212), and the compressed liquid stream (9a) can be heat exchanged with the third stream (7) in the gas phase in the second heat exchanger (211b) to be converted back into a gas-liquid mixed phase stream (9b). For example, the temperature of the gas-liquid mixed phase stream (10) can be 70°C to 95°C, specifically 80°C to 90°C.

[0064] According to one embodiment of the present invention, the volumetric flow rate of the liquefied third stream (8, 8b) may be 10% to 20%, specifically 12% to 18%, and more specifically 13% to 17%, relative to the volumetric flow rate of the gaseous third stream (7). At this time, the internal diameter of the pipe of the liquefied third stream (8, 8b) relative to the internal diameter (D) of the pipe of the gaseous third stream (7) may be about (1 / 4)D to (3 / 4)D, specifically (1 / 3)D to (1 / 2)D. In this way, when the unreacted propylene monomer discharged to the upper portion of the absorption tower is circulated to the reaction unit (100), the size of the transport pipe can be significantly reduced by reducing the volumetric flow rate through liquefaction of the third stream (7).

[0065] The liquefied third stream (8, 8b) can be supplied to the reaction unit (100) using a pump (212). Previously, as shown in FIG. 3, a compressor (213) was used to transport a gaseous stream to the reaction unit (100), but in the present invention, the gaseous upper stream of the absorption tower can be liquefied by a heat exchanger and then transported to the reaction unit (100) using a pump (212). When the pump (212) is used instead of the compressor, operation and maintenance become easier, and the device cost is economical. In addition, when the upper stream of the absorption tower is liquefied and transported by the pump (212), the power usage can be reduced to less than about 10% compared to when the compressor (213) is used, so that significant energy savings are possible.

[0066] According to one embodiment of the present invention, the liquefied third stream (9, 9b) can exchange heat with the first stream (4) through the first heat exchanger (214). Referring to FIG. 1, when one heat exchanger (211) is used, the liquid stream (9) transferred by the pump (212) can be converted into a gaseous or gas-liquid mixed phase stream (10) by exchanging heat with the gaseous first stream (4) through the first heat exchanger (214). Furthermore, referring to FIG. 2, when two heat exchangers (211a, 211b) are used, the secondarily condensed liquid third stream (8b) is converted into a gas-liquid mixed phase again in the second heat exchanger (211b), and the gas-liquid mixed phase stream (9b) can be converted into a gaseous phase by exchanging heat with the first stream (4) through the first heat exchanger (214). The temperature of the gaseous stream (10) passing through the first heat exchanger (214) may be, for example, 80°C to 100°C, specifically 85°C to 95°C. The stream (10, 11) recycled to the reaction unit (100) should be supplied to the reaction unit after recovering heat as much as possible through the heat exchanger, thereby reducing the amount of heat source (steam) used in the heating means (121), thereby reducing energy usage.

[0067] Furthermore, as illustrated in FIGS. 1 and 2, the third stream (10) that has passed through the first heat exchanger (214) may be branched, such that a portion of the stream (11) may be supplied to the reaction unit (100), and the remainder stream (12) may be supplied to the gas purification unit (300). At this time, both the portion of the stream (11) and the remainder stream (12) may be gaseous streams. More specifically, the stream (11) supplied to the reaction unit (100) may be mixed with the liquid feed stream (1) and supplied to the reaction unit (100) as a gas-liquid mixed phase stream (14), and a portion of the stream (12) supplied to the gas purification unit (300) may be recycled to the reaction unit (100) as a second recycle stream (13) containing unreacted propylene monomer purified after passing through the gas purification process. That is, a portion of the gaseous stream (i.e., the first recycle stream) (11) branched from the third stream (10) that has passed through the first heat exchanger (214) can be mixed with the second recycle stream (13) purified in the gas purification unit (300) and the liquid feed stream (1) and supplied to the reaction unit (100) as a gas-liquid mixed phase stream (14).

[0068] Meanwhile, according to one embodiment of the present invention, the fourth liquid stream (6) containing water and isopropyl alcohol discharged from the lower portion of the absorption tower (210) can be supplied to the isopropyl alcohol purification unit (400).

[0069] According to one embodiment of the present invention, the bottom discharge stream of the absorption tower (210) may contain a small amount of unreacted propylene monomer in addition to isopropyl alcohol and unreacted water. For example, the content of unreacted propylene monomer contained in the bottom discharge stream of the absorption tower (210) may be 5 wt% or less, specifically 3 wt% to 5 wt%. Accordingly, all or a portion of the bottom discharge stream containing isopropyl alcohol from the absorption tower (210) may be supplied to a flash drum and / or a gas purification column to separate the unreacted propylene monomer contained in the bottom discharge stream of the absorption tower (210) into an upper discharge stream, and the bottom discharge stream containing isopropyl alcohol and unreacted water may be supplied to an isopropyl alcohol purification unit (400).

[0070] For example, the fourth stream (6) discharged from the bottom of the absorption tower (210) may pass through one or more flash drums before being supplied to the isopropyl alcohol purification unit (400). More specifically, the fourth stream (6) discharged from the bottom of the absorption tower (210) may be supplied to the gas purification unit (300) by using a flash drum, with a portion of the fourth stream (6) being supplied to the gas purification unit (300), and the remaining stream being supplied to the isopropyl alcohol purification unit (400). In addition, the unreacted propylene monomer contained in the fourth stream (6) may be separated as an upper discharge stream of the flash drum and supplied to the gas purification unit (300), and the isopropyl alcohol may be supplied to the isopropyl alcohol purification unit (400) as a lower discharge stream of the flash drum.

[0071] Furthermore, the upper discharge stream of the flash drum is purified once more through the gas purification column of the gas purification unit (300), so that a portion of the stream (13) containing unreacted propylene monomer is discharged to the upper portion of the gas purification column of the gas purification unit (300) and recycled to the reaction unit (100), and the remaining stream containing isopropyl alcohol discharged to the lower portion of the gas purification column of the gas purification unit (300) can be supplied to the isopropyl alcohol purification unit (400). At this time, it is preferable to vent inert gases such as ethane and propane that should not be accumulated in the process.

[0072] According to one embodiment of the present invention, in the method for producing isopropyl alcohol, if necessary, additional devices such as a distillation column, a condenser, a reboiler, a valve, a pump, a separator, and a mixer can be additionally installed and used.

[0073] Above, the method for producing isopropyl alcohol according to the present invention 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 invention, 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 producing isopropyl alcohol according to the present invention.

[0074]

[0075] Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by the following examples.

[0076] [Example]

[0077] Example 1

[0078] As shown in the process flow diagram in Fig. 1, a process for producing a reaction product containing isopropyl alcohol (IPA) and separating isopropyl alcohol from the reaction product was simulated using Aspen Plus from Aspen.

[0079] Specifically, 40 kg / cm 2 ·The feed stream (1) was supplied at a flow rate of 5 ton / hr to the reactor (110) operated at a pressure of G and a temperature of 192°C to 208°C, and the molar ratio of water and propylene monomer supplied to the reaction section (100) was controlled to 0.4, and ethane and propane were included as inert gases.

[0080] The gaseous reaction product stream (3) discharged from the above reactor (110) is separated into a first gaseous stream (4) and a second liquid stream (5) while passing through one reaction section heat exchanger (120) and discharged. The first stream (4) is partially condensed into a liquid phase in the first heat exchanger (214) and then supplied to the lower part of the absorption tower (210), and the second stream (5) is supplied to the lower part of the absorption tower (210).

[0081] The above absorption tower (210) has a temperature of 90°C to 100°C and a pressure of 31 kg / cm 2 ·G to 32 kg / cm 2 ·Operated at a pressure of G, the isopropyl alcohol in the reaction product stream was absorbed using water supplied as a solvent to the top of the absorption tower (210), and separated into a third stream (7), which is an upper discharge stream containing propylene monomer, and a fourth stream (6), which is a lower discharge stream containing water and isopropyl alcohol.

[0082] Specifically, the third gaseous stream (7) discharged from the upper portion of the absorption tower (210) was liquefied (8) by cooling it to a temperature of 60°C to 70°C in a heat exchanger (211), and the liquid stream (9) compressed by a pump (212) was heat-exchanged with the first stream (4) in the first heat exchanger (214) and then refluxed to the reaction unit (100). Meanwhile, the fourth stream (6) from the lower portion of the absorption tower (210) was supplied to an IPA purification unit to obtain isopropyl alcohol from which water was removed.

[0083] Example 2

[0084] As shown in the process flow diagram in Fig. 2, the process of producing a reaction product containing isopropyl alcohol (IPA) and separating isopropyl alcohol from the reaction product was simulated using Aspen Plus from Aspen.

[0085] Specifically, 40 kg / cm 2 ·The feed stream (1) was supplied at a flow rate of 5 ton / hr to the reactor (110) operated at a pressure of G and a temperature of 192°C to 208°C, and the molar ratio of water and propylene monomer supplied to the reaction section (100) was controlled to 0.4, and ethane and propane were included as inert gases.

[0086] The gaseous reaction product stream (3) discharged from the above reactor (110) is separated into a first gaseous stream (4) and a second liquid stream (5) while passing through a reaction section heat exchanger (120) and discharged. The first stream (4) is partially condensed into a liquid phase in the first heat exchanger (214) and then supplied to the lower part of the absorption tower (210), and the second stream (5) is supplied to the lower part of the absorption tower (210).

[0087] The above absorption tower (210) has a temperature of 90°C to 100°C and a pressure of 31 kg / cm 2 ·G to 32 kg / cm 2·Operated at a pressure of G, the isopropyl alcohol in the reaction product stream was absorbed using water supplied as a solvent to the top of the absorption tower (210), and separated into a third stream (7), which is an upper discharge stream containing propylene monomer, and a fourth stream (6), which is a lower discharge stream containing water and isopropyl alcohol.

[0088] Specifically, the third stream (7) of gaseous phase discharged from the upper portion of the absorption tower (210) was liquefied by cooling to a temperature of 60° C. to 70° C. through the second heat exchanger and the third heat exchanger (211a, 211b), and the liquid stream (8b) was compressed by a pump (212), and then the compressed liquid stream (9a) was passed through the second heat exchanger (211b) again to exchange heat with the third stream (7), and the stream (9b) that passed through the second heat exchanger (211b) was heat-exchanged with the first stream (4) in the first heat exchanger (214) and then refluxed to the reaction unit (100). Meanwhile, the fourth stream (6) from the lower portion of the absorption tower (210) was supplied to an IPA purification unit to obtain isopropyl alcohol from which water had been removed.

[0089] Comparative Example 1

[0090] As shown in the process flow diagram in Fig. 3, the process of producing a reaction product containing isopropyl alcohol (IPA) and separating isopropyl alcohol from the reaction product was simulated using Aspen Plus from Aspen.

[0091] Specifically, 40 kg / cm 2 ·The feed stream (1) was supplied at a flow rate of 5 ton / hr to the reactor (110) operated at a pressure of G and a temperature of 192°C to 208°C, and the molar ratio of water and propylene monomer supplied to the reaction section (100) was controlled to 0.4, and ethane and propane were included as inert gases.

[0092] The gaseous reaction product stream (3) discharged from the above reactor (110) is separated into a first gaseous stream (4) and a second liquid stream (5) while passing through a reaction section heat exchanger (120) and discharged. The first stream (4) is partially condensed into a liquid phase in the first heat exchanger (214) and then supplied to the lower part of the absorption tower (210), and the second stream (5) is supplied to the lower part of the absorption tower (210).

[0093] The above absorption tower (210) has a temperature of 90°C to 100°C and a pressure of 31 kg / cm 2 ·G to 32 kg / cm 2 ·Operated at a pressure of G, the isopropyl alcohol in the reaction product stream was absorbed using water supplied as a solvent to the top of the absorption tower (210), and separated into a third stream (7), which is an upper discharge stream containing propylene monomer, and a fourth stream (6), which is a lower discharge stream containing water and isopropyl alcohol.

[0094] Specifically, the third stream (7) of the gaseous phase discharged from the upper portion of the absorption tower (210) was compressed by a compressor (213), and then the compressed gaseous phase stream (15) was refluxed to the reaction unit (100). Meanwhile, the fourth stream (6) from the lower portion of the absorption tower (210) was supplied to an IPA purification unit to obtain isopropyl alcohol from which water had been removed.

[0095] Experimental example

[0096] Table 1 below compares the phase, temperature, and relative volumetric flow rate of the stream after passing through the pump (212) or compressor (213) and the relative power consumption consumed in the pump (212) or compressor (213) in the examples and comparative examples. Here, the relative volumetric flow rate and power consumption of examples 1 and 2 are shown as relative values ​​with Comparative Example 1 as 100% as the standard.

[0097] Example 1 (Fig. 1) Example 2 (Fig. 2) Comparative Example 1 (Fig. 3) Absorption tower top compression post-stream (9, 9a, 15) phase Liquid phase Liquid phase phase temperature 70℃ 70℃ 120℃ Volume flow rate 15.2% 15.2% 100% Power usage of pump (212) or compressor (213) 5.1% 5.1% 100%

[0098] Referring to Table 1 above, when the conditions of the gaseous stream (7) discharged from the top of the absorption tower are all the same, and the volumetric flow rate of Comparative Example 1, in which the gaseous stream (7) is transferred to the reaction unit (100) using the compressor (213), is 100%, the relative volumetric flow rates of Examples 1 and 2, in which the gaseous stream (7) is liquefied through the heat exchanger (211, 211a, 211b) and then transferred to the reaction unit (100) using the pump (212), are significantly reduced to the level of 15.2%. Accordingly, it was confirmed that Examples 1 and 2 can use a smaller-sized pipe for stream transfer compared to Comparative Example 1, thereby improving process efficiency and reducing process costs.

[0099] In addition, when the power consumption of Comparative Example 1, in which the gaseous absorption tower upper discharge stream was compressed and transported by a compressor (213), was 100%, the relative power consumption of Examples 1 and 2, in which the gaseous absorption tower upper discharge stream was converted to a liquid phase and then transported by a pump (212), was significantly reduced to 5.1%, confirming that power consumption could be reduced.

[0100] In addition, Table 2 below shows a comparison of the relative refrigerant usage consumed in the cooling heat exchanger (211, 211a) in which the refrigerant is used to liquefy the gaseous absorption tower upper discharge stream (7) in Examples 1 and 2. Here, the relative refrigerant usage is shown by comparing the relative refrigerant usage of Example 2 with the refrigerant usage of Example 1 as 100%.

[0101] Example 1 (Fig. 1) Example 2 (Fig. 2) Refrigerant usage 100% 79% Cooling and heat recovery heat exchanger - heat exchanger (211b)

[0102] Referring to Table 2 above, it can be confirmed that the refrigerant usage is reduced by about 21% in Example 2, which is equipped with two cooling heat exchangers (211a, 211b), compared to Example 1, which is equipped with only one cooling heat exchanger (211) to liquefy the vapor phase absorption tower discharge stream. More specifically, in Example 2, in addition to the heat exchanger (211a) in which the refrigerant is used, the vapor phase absorption tower discharge stream (7) and the stream (9a) liquefied and transported through the refrigerant-using heat exchanger (211a) are heat-exchanged with each other through an additional heat exchanger (211b), thereby simultaneously achieving cooling and heat recovery of the vapor phase absorption tower discharge stream (7), thereby reducing the refrigerant usage rate.

[0103] Although exemplary embodiments of the present invention have been described above, the present invention 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.

[0104] [Explanation of symbols]

[0105] 100: Reaction section 200: Purification section

[0106] 300: Gas purification unit 400: Isopropyl alcohol purification unit

[0107] 110: Reactor 210: Absorption tower

[0108] 120: Heat exchanger of the reaction section 121: Heating means

[0109] 211, 211a, 211b, 214: Heat exchangers of the purification unit

[0110] 212: Pump 213: Compressor

Claims

1. A step of supplying a feed stream containing propylene monomer and water to a reaction unit to react and producing a reaction product containing isopropyl alcohol, propylene monomer and water; A step of supplying a first stream containing a gaseous reaction product discharged from the above reaction unit and a second stream containing a liquid reaction product to an absorption tower of a purification unit, respectively; and A step of circulating a third gaseous stream containing propylene monomer discharged from the upper portion of the absorption tower to the reaction unit, and supplying a fourth liquid stream containing water and isopropyl alcohol discharged from the lower portion of the absorption tower to an isopropyl alcohol purification unit; The above purification unit includes one or more heat exchangers, A method for producing isopropyl alcohol, comprising converting the third stream from a gaseous phase to a liquid phase and transporting it through one or more heat exchangers provided in the purification unit when circulating the third stream to the reaction unit.

2. In paragraph 1, When supplying the above first stream to the absorption tower, A method for producing isopropyl alcohol, comprising partially condensing the first stream through a first heat exchanger provided in the purification unit and supplying it to the absorption tower as a gas-liquid mixed phase.

3. In paragraph 2, A method for producing isopropyl alcohol, comprising exchanging heat between the third stream converted to liquid and the first stream through the first heat exchanger.

4. In paragraph 1, The liquid conversion of the third stream is Firstly condensing the third stream discharged from the upper portion of the absorption tower through a second heat exchanger provided in the purification unit; and A method for producing isopropyl alcohol, comprising: secondarily condensing the first condensed third stream through a third heat exchanger provided in the purification unit.

5. In paragraph 4, The above first condensed third stream is a gas-liquid mixed phase stream, A method for producing isopropyl alcohol, wherein the second condensed third stream is a liquid stream.

6. In paragraph 4, A method for producing isopropyl alcohol, wherein the temperature of the first condensed third stream is 90°C to 100°C.

7. In paragraph 4, A method for producing isopropyl alcohol, wherein the temperature of the secondarily condensed third stream is 50°C to 70°C.

8. In paragraph 4, A method for producing isopropyl alcohol, comprising exchanging heat between the third stream discharged from the upper portion of the absorption tower and the secondarily condensed third stream through the third heat exchanger provided in the purification unit.

9. In paragraph 8, A method for producing isopropyl alcohol, wherein the second condensed third stream passing through the third heat exchanger is a gas-liquid mixed phase stream.

10. In paragraph 1, A method for producing isopropyl alcohol, wherein the third stream converted into the liquid phase is supplied to the reaction unit using a pump.

11. In paragraph 1, The above reaction section includes a reactor and one or more heat exchangers, A feed stream is supplied to the above reactor to react and form a gaseous reaction product, A method for producing isopropyl alcohol, wherein a gaseous reaction product stream discharged from the reactor is separated into a first stream containing a gaseous reaction product and a second stream containing a liquid reaction product while passing through one or more heat exchangers provided in the reaction section, and each stream is supplied to an absorption tower.

12. In paragraph 11, The above feed stream passes through one or more heat exchangers before being supplied to the reactor, A method for producing isopropyl alcohol, wherein the temperature of the feed stream passing through the one or more heat exchangers is 160°C to 180°C.

13. In paragraph 1, A method for producing isopropyl alcohol, wherein the temperatures of the first stream and the second stream are each 110°C to 130°C.

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