Isopropyl alcohol manufacturing method and manufacturing apparatus

Abstract

The present invention provides a method for producing isopropyl alcohol, the method comprising the steps of: (S1) supplying a feedstream containing propylene monomer and water to a reactor in the presence of a catalyst to perform a gas-phase reaction; (S2) partially condensing a reaction product obtained by the gas-phase reaction in a heat exchanger, transferring the uncondensed gas-phase reaction product to an absorption tower, and transferring a portion of the condensed liquid-phase reaction product to a pH measurement system connected online between the heat exchanger and the absorption tower; (S3) measuring the pH of the liquid-phase reaction product transferred to the pH measurement system to calculate the catalyst content, and replenishing the reactor with catalyst corresponding to the calculated content; and (S4) dissolving and separating isopropyl alcohol contained in the gas-phase reaction product in absorbing water in the absorption tower. The method also provides an apparatus for carrying out the method.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0100549 filed on August 11, 2022 and Korean Patent Application No. 10-2022-0179081 filed on December 20, 2022, and all contents disclosed in the documents of the relevant Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a method and apparatus for producing isopropyl alcohol, and more particularly to an isopropyl alcohol production method and apparatus that can maintain reactor performance by predicting the amount of catalyst loss in a reactor and replenishing the catalyst in real time. The present invention relates to a method and apparatus for producing isopropyl alcohol. [Background technology]

[0003] Isopropyl alcohol (IPA) is used in a variety of applications, including as a cleaning agent in the electronics industry, such as in the manufacturing of semiconductors and liquid crystal displays (LCDs), as a raw material for industrial coatings and reagents, and as a solvent for paints and inks.

[0004] Isopropyl alcohol can be produced by reacting propylene with water. For example, propylene monomer and water are reacted in a gas phase in a reactor under high pressure and high temperature in the presence of an acidic catalyst to obtain a reaction product containing isopropyl alcohol, unreacted propylene monomer, and water. The gaseous reaction product is then transferred to an absorption tower via a heat exchanger, and a gaseous stream containing unreacted propylene monomer is discharged from the upper part. A mixture of isopropyl alcohol and water is separated in the lower part of the absorption tower, and isopropyl alcohol can be purified from the mixture. The water separated from the mixture can be recycled and utilized as process water, and a portion is discharged as wastewater.

[0005] The acidic catalyst may be a phosphoric acid-based catalyst such as SiO-supported HPO, and some of the phosphoric acid may be lost in the reactor due to incorporation into the reaction product, which may reduce the reaction efficiency and the final isopropyl alcohol yield.

[0006] Therefore, a process is required to predict the amount of phosphoric acid lost in the reactor and to replenish it in order to maintain reaction efficiency.

[0007] FIG. 1 is a diagram showing a schematic diagram of the process for predicting catalyst loss in a conventional isopropyl alcohol production process. After sampling a portion of the stream from the piping between the heat exchanger and the absorption tower, the pH of the sample solution is measured, and the amount of phosphoric acid loss in the reactor can be predicted and replenished from the results.

[0008] In the above-mentioned conventional techniques, the pH is measured offline by sampling the high-pressure reaction product, which causes environmental and safety problems such as steam generation during the sampling process. Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention is intended to solve the problems mentioned in the Background of the Invention section above, and provides a method and apparatus for predicting and replenishing catalyst loss in real time to maintain the reaction efficiency of propylene and water during the production of isopropyl alcohol. [Means for solving the problem]

[0010] According to one aspect of the present invention for solving the above problem, (S1) supplying a feed stream containing propylene monomer and water to a reactor in the presence of a catalyst to cause a gas phase reaction; (S2) a step of partially condensing the reaction product obtained by the gas phase reaction in a heat exchanger, and then transferring the uncondensed gas phase reaction product to an absorption tower, and transferring a portion of the condensed liquid phase reaction product to a pH measurement system connected online between the heat exchanger and the absorption tower; (S3) measuring the pH of the liquid-phase reaction product transferred to the pH measurement system to calculate the catalyst content, and replenishing the catalyst corresponding to the calculated content into the reactor; (S4) dissolving the isopropyl alcohol contained in the gas-phase reaction product in absorbing water in the absorption tower and separating the isopropyl alcohol.

[0011] Furthermore, according to another aspect of the present invention, a reactor for reacting propylene monomer and water in the presence of a catalyst; a heat exchanger for partially condensing gas phase reaction products obtained from the reactor; an absorption tower for separating isopropyl alcohol contained in the gas-phase reaction product transferred from the heat exchanger; An apparatus for producing isopropyl alcohol is provided, including a pH measurement system connected online between the heat exchanger and the absorption tower. [Effects of the Invention]

[0012] According to the present invention, in order to maintain the reaction efficiency of propylene and water during the production of isopropyl alcohol, the pH of the reaction product is measured online and the amount of catalyst lost is calculated from the measurement result, thereby predicting and replenishing the amount of catalyst lost in real time, thereby maintaining the reaction efficiency of producing isopropyl alcohol.

[0013] Furthermore, the online pH measurement does not require a separate sampling process as in the conventional offline method, and therefore is advantageous in terms of the environment and safety as it prevents the generation of steam. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic diagram illustrating a process of measuring pH offline after sampling a portion of a reaction product in a conventional isopropyl alcohol production process. [Figure 2] FIG. 1 is a schematic diagram illustrating a process for producing isopropyl alcohol, including an online pH measurement step of the reaction product, according to one embodiment of the present invention. [Figure 3] FIG. 1 is a diagram illustrating an example in which an online pH measurement system is applied to a process for producing isopropyl alcohol according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0016] As used herein, the meaning of "comprise" or "contain" is to embody a particular property, region, constant, step, operation, element, or component, and does not exclude the addition of other particular properties, regions, constants, steps, operations, elements, or components.

[0017] The term "stream" as used herein may refer to the flow of fluid within a process or the fluid itself flowing in a pipe. Specifically, the stream may simultaneously refer to the fluid itself flowing in a pipe connecting each device and the flow of the fluid. The fluid may contain one or more components of gas, liquid, or solid.

[0018] One embodiment of the present invention relates to a method for producing isopropyl alcohol (IPA), specifically including a step (S1) of feeding and reacting in the presence of a catalyst, a step (S2) of partially condensing and transferring the reaction product, a step (S3) of measuring the online pH of the liquid-phase reaction product obtained by partial condensation, and a step (S4) of separating isopropyl alcohol from the reaction product.

[0019] FIG. 2 is a schematic diagram illustrating a process for producing isopropyl alcohol, including an online pH measurement step of a reaction product, according to one embodiment of the present invention. Hereinafter, the process for producing isopropyl alcohol according to the present invention will be described step by step with reference to FIG.

[0020] First, a reactor is filled with a catalyst, and then a feed stream containing propylene monomer and water is supplied to the reactor to carry out a gas phase reaction, and a gas phase stream containing isopropyl alcohol, unreacted propylene monomer, unreacted water, the catalyst used in the reaction, and impurities is obtained as a reaction product (S1).

[0021] In the feedstream supplied to the reactor, the molar ratio of water to propylene monomer may be 0.3 to 0.5, 0.35 to 0.5, or 0.35 to 0.45. When this molar ratio is satisfied, the forward reaction of the equilibrium reaction is promoted and the reverse reaction is prevented, thereby increasing the yield of isopropyl alcohol.

[0022] The reactor can be operated under optimal conditions for efficiently producing isopropyl alcohol through the gas phase reaction of propylene monomer and water. For example, the operating pressure of the reactor can be 30 to 50 kg / cm. 2 g, 35~50kg / cm 2 g or 35~45kg / cm 2 ·g, and the operating temperature can be 180 to 220°C, 185 to 220°C, or 185 to 215°C.

[0023] The catalyst promotes the reaction of propylene and water used as raw materials to improve the conversion rate of propylene to isopropyl alcohol and the resulting final yield of isopropyl alcohol. An acidic catalyst, for example, a phosphoric acid catalyst, may be used.

[0024] In order to increase the efficiency of the gas-phase reaction of propylene and water, it is necessary to increase the catalyst life, which may result in a loss of phosphoric acid in the reactor due to a portion of the phosphoric acid, which is an active component of the catalyst, being introduced into the reaction product. To replenish the catalyst lost in the reactor, the phosphoric acid component must be replenished continuously or discontinuously, and the amount of phosphoric acid to be replenished can be determined by analyzing the pH of the effluent after the reaction.

[0025] To this end, in the method for producing isopropyl alcohol according to the present invention, the gas phase reaction product obtained in the reactor is transferred to a heat exchanger and partially condensed, and then the uncondensed gas phase reaction product is transferred to an absorption tower, and a portion of the condensed liquid phase reaction product is transferred to a pH measurement system connected online between the heat exchanger and the absorption tower (S2).

[0026] Specifically, the reaction product obtained under the high pressure and high temperature conditions of the reactor may be partially condensed into a liquid and gas mixture by heat exchange with the feed stream supplied to the reactor, i.e., gas-liquid separation of the reaction product occurs in the heat exchanger.

[0027] For example, the temperature of the feed stream before passing through the heat exchanger can be 90 to 130°C, 95 to 130°C, or 95 to 125°C, and the temperature of the feed stream after passing through the heat exchanger can be 160 to 210°C, 165 to 210°C, or 170 to 200°C. Furthermore, the temperature of the stream condensed after passing through the heat exchanger can be 100 to 140°C, 110 to 140°C, or 110 to 130°C.

[0028] If necessary, the stream condensed after passing through the heat exchanger can be further condensed using a cooler.

[0029] In this way, the reaction product is converted into a gas-liquid mixture stream by heat exchange with the feed stream, and the feed stream is preheated and supplied to the reactor, thereby reducing the energy required to heat the feed stream.

[0030] The gas-liquid mixture obtained by partial condensation through the heat exchange can be separated into a gas phase and a liquid phase in the heat exchanger itself, or a separator can be installed downstream of the heat exchanger to separate the gas phase and the liquid phase.

[0031] The separated gaseous reaction product stream is then transferred to an absorption tower, and a portion of the liquid reaction product is transferred to a pH measurement system connected online between the heat exchanger and the absorption tower to measure the pH in order to determine the phosphoric acid content of the introduced catalyst (S3).

[0032] 3 shows an example of an application of an online pH measurement system to a process for producing isopropyl alcohol according to one embodiment of the present invention, and the pH measurement system can include a pressure reducing unit 10, a gas removing unit 20, a cooling unit 30, a pH measuring unit 40, and a computing unit 50. When such an online pH measurement system is used, a separate sampling process that has conventionally been performed when measuring the pH of a reaction product can be omitted.

[0033] 3, a partial stream 100 of the liquid-phase reaction product obtained by partial condensation through heat exchange is transferred to a reduced pressure section 10 of a pH measurement system connected by a line between the heat exchanger and the absorption tower. The transfer of the liquid-phase reaction product can be controlled by controlling the pressure using a valve means installed on the line.

[0034] In the pressure reducing section 10 of the pH measurement system, the liquid phase reaction product is obtained by condensation in the heat exchanger at the downstream side of the reactor, so the pressure at the downstream side of the reactor is about 30 kg / cm 2 To show the high pressure stream of .g, a pressure reduction is performed to adjust the liquid phase reaction product to the pressure range required for the pH measurement system.

[0035] For example, a portion of the liquid phase stream obtained by partial condensation in the heat exchanger is transferred at a flow rate of 15 to 100 L / H, and the pressure of the transferred stream is reduced in a pressure reducing unit included in the pH measurement system to a range of 1 / 25 to 1 / 35 of the initial pressure, for example, 1 kg / cm, which is the atmospheric pressure level. 2 It can be lowered to g.

[0036] Meanwhile, gas may be generated during the decompression of the liquid stream. If such gas is introduced into the liquid stream, an error may occur in the pH measurement, and therefore, it is necessary to remove the gas.

[0037] Therefore, the gas can be removed by passing the depressurized liquid phase stream through the gas removal unit 20 of the pH measurement system, thereby preventing the inflow of gas components into the liquid stream during the subsequent cooling process. The gas removal unit 20 may be in the form of a separator that separates a fluid having two or more phases, such as a knockout drum, but is not limited thereto.

[0038] The liquid phase stream from which the gas has been removed is transferred to the cooling section 30 of the pH measurement system, and a coolant (e.g., a refrigerant) is supplied to the lower end of the cooling section 30, moved to the upper end, and then discharged, thereby lowering the temperature of the liquid phase stream to a range of 20 to 40°C.

[0039] The pH of the cooled liquid phase stream is measured by pH measuring unit 40, and the amount of phosphoric acid-based catalyst lost in the reaction mixture is calculated from the pH measurement result by calculating unit 50. The phosphoric acid-based catalyst corresponding to the calculated amount is replenished to the reactor, thereby extending the catalyst life in the reactor and ensuring the final isopropyl alcohol yield. Here, the catalyst replenishment can be performed by controlling the pump flow rate of the catalyst supply line connected to the reactor.

[0040] Furthermore, the liquid phase stream that has passed through the cooling section (3) and the pH measurement section 40 can be transferred to another separator, for example, a knock-out drum (KO drum), and trace amounts of gas components remaining in the other separator can be discharged together with the gas components removed in the gas removal section 20.

[0041] Meanwhile, after gas-liquid separation in the heat exchanger, the gas phase reaction product is transferred to an absorption tower, where absorbing water is used to dissolve the isopropyl alcohol contained in the reaction product and separate it at the bottom, and a stream containing unreacted propylene monomer contained in the reaction product can be separated at the top (S4).

[0042] In one embodiment of the present invention, the absorber may be operated under conditions that effectively separate an upper stream containing unreacted propylene monomer from a lower stream containing isopropyl alcohol. For example, the operating pressure of the absorber may be 20 to 40 kg / cm. 2 g, 25~40kg / cm 2 g or 25~35kg / cm 2 ·g, and the operating temperature can be in the range of 80 to 110°C, 90 to 110°C, or 90 to 100°C.

[0043] The stream containing isopropyl alcohol and water separated at the bottom of the absorption tower is supplied to a purification unit where the water is separated to obtain high-purity isopropyl alcohol. The water separated in the purification unit can be recovered and reused as process water or discharged as wastewater.

[0044] Meanwhile, the stream containing the unreacted propylene monomer separated at the top of the absorption tower may contain impurities such as inert gases, and may be passed through an inert gas removal column so that the unreacted propylene monomer can be used again to produce isopropyl alcohol.

[0045] If necessary, the method for producing isopropyl alcohol according to the present invention may further include and use devices such as a distillation column, a condenser, a reboiler, a valve, a pump, a separator, and a mixer.

[0046] According to the present invention, in order to maintain the reaction efficiency of propylene and water during the production of isopropyl alcohol, the pH of the reaction product is measured online and the catalyst content is calculated from the measurement result, thereby predicting the amount of catalyst loss in real time and replenishing it, thereby maintaining the yield of isopropyl alcohol.

[0047] Furthermore, the above-described online pH measurement does not require a separate sampling process as in the conventional offline method, and therefore, steam generation is suppressed, which is advantageous in terms of the environment and safety.

[0048] The method for producing isopropyl alcohol of the present invention as described above can be carried out using an apparatus including an online pH measurement system.

[0049] Therefore, the present invention further provides an apparatus for producing isopropyl alcohol, comprising: a reactor for reacting propylene monomer and water in the presence of a catalyst; a heat exchanger for partially condensing a gas-phase reaction product obtained from the reactor; an absorption tower for separating isopropyl alcohol contained in the gas-phase reaction product transferred from the heat exchanger; and a pH measurement system connected online between the heat exchanger and the absorption tower.

[0050] In the above manufacturing apparatus, the explanations regarding the configurations that overlap with those in the above manufacturing method are the same.

Claims

1. (S1) supplying a feed stream containing propylene monomer and water to a reactor in the presence of a catalyst to cause a gas phase reaction; (S2) partially condensing the reaction product obtained by the gas phase reaction in a heat exchanger, and then transferring the uncondensed gas phase reaction product to an absorption tower, and transferring a portion of the condensed liquid phase reaction product to a pH measurement system connected online between the heat exchanger and the absorption tower; (S3) measuring the pH of the liquid-phase reaction product transferred to the pH measurement system to calculate the catalyst content, and replenishing the reactor with catalyst corresponding to the calculated content; (S4) dissolving the isopropyl alcohol contained in the gas phase reaction product in the absorption tower in absorbing water and separating it.

2. 2. The method for producing isopropyl alcohol according to claim 1, wherein the gas phase reaction product is a gas phase stream containing isopropyl alcohol, unreacted propylene monomer, unreacted water, the catalyst used in the reaction, and impurities.

3. The method for producing isopropyl alcohol according to claim 1 , wherein the catalyst comprises a phosphoric acid-based catalyst.

4. The method for producing isopropyl alcohol according to claim 1, wherein the gaseous reaction product in the heat exchanger is condensed to 100 to 140 ° C. by heat exchange with the feed stream supplied to the reactor.

5. 2. The method for producing isopropyl alcohol according to claim 1, wherein a portion of the liquid phase of the reaction product obtained by condensation in the heat exchanger is transferred to a pH measurement system connected online by pressure control.

6. 2. The method for producing isopropyl alcohol according to claim 1, wherein the pH of the liquid-phase reaction product transferred to the pH measurement system is measured after undergoing decompression, gas removal, and cooling processes.

7. The method for producing isopropyl alcohol according to claim 6, wherein the pressure of the liquid-phase reaction product is reduced in the range of 1 / 25 to 1 / 35 of the initial pressure transferred to the pH measurement system.

8. The method for producing isopropyl alcohol according to claim 6, wherein the removal of gas from the liquid-phase reaction product is removal of gas generated during a decompression process.

9. The method for producing isopropyl alcohol according to claim 6, wherein the reaction product is cooled at a temperature of 20 to 40 ° C. using a refrigerant.

10. a reactor for reacting propylene monomer and water in the presence of a catalyst; a heat exchanger for partially condensing the gas phase reaction product obtained from the reactor; an absorption tower for separating isopropyl alcohol contained in the gas-phase reaction product transferred from the heat exchanger; and a pH measurement system connected online between the heat exchanger and the absorption tower.

11. The isopropyl alcohol manufacturing apparatus according to claim 10, wherein the pH measurement system includes a pressure reducing unit, a gas removing unit, a cooling unit, a pH measuring unit, and a calculation unit.

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