Method and apparatus for preparing isopropyl alcohol

Abstract

The present invention provides a method for producing isopropyl alcohol, comprising the steps of: (S1) supplying a feed stream containing propylene monomer and water in the presence of a catalyst to a reactor to perform a gas-phase reaction; (S2) partially condensing the reaction product obtained by the gas-phase reaction in a heat exchanger, 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 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 system to calculate the catalyst content and replenishing the reactor with a catalyst corresponding to the calculated content; and (S4) separating the isopropyl alcohol contained in the gas-phase reaction product in the absorption tower by dissolving it in absorbing water.

Description

Technology Field

[0001] The present invention relates to a method and apparatus for producing isopropyl alcohol, and more specifically, to a method and apparatus for producing isopropyl alcohol that can maintain reactor performance by predicting the amount of catalyst loss in the reactor and replenishing the catalyst in real time. Background Technology

[0002] Isopropyl alcohol (IPA) is used in various applications in the electronics industry, such as semiconductor and LCD (Liquid crystal display) manufacturing, including as a cleaning agent, industrial paint and reagent raw material, and as a solvent for paints and inks.

[0003] Isopropyl alcohol can be produced by reacting propylene with water. For example, propylene monomer and water are reacted in the gas phase in a reactor under high pressure and high temperature conditions in the presence of an acidic catalyst to obtain a reaction product comprising isopropyl alcohol, unreacted propylene monomer, and water. The gas phase reaction product then passes through a heat exchanger to an absorption tower, where a gas phase stream containing unreacted propylene monomer is discharged from the top and a mixture of isopropyl alcohol and water is separated from the bottom of the absorption tower. The isopropyl alcohol can then be purified from the mixture. The water separated from the mixture can be recycled and utilized as process water, while a portion is discharged as wastewater.

[0004] Phosphate-based catalysts such as SiO2-supported H3PO4 can be used as the acidic catalyst mentioned above, but phosphoric acid loss may occur within the reactor as some of the phosphoric acid is introduced into the reaction product, which may lead to a decrease in reaction efficiency and a reduction in the yield of the final isopropyl alcohol.

[0005] Therefore, it is necessary to predict the amount of phosphoric acid lost in the reactor and replenish it to maintain reaction efficiency.

[0006] Figure 1 schematically illustrates the process of predicting the amount of catalyst loss performed in a conventional isopropyl alcohol manufacturing process. By taking a portion of the stream from the piping between the heat exchanger and the absorption tower, sampling, and measuring the pH of the obtained sample solution, the amount of phosphoric acid loss in the reactor can be predicted and supplemented from the result.

[0007] In the conventional technology described above, since the pH is measured offline by sampling the reaction product under high pressure, environmental and safety issues, such as steam generation during the sampling process, arise. The problem to be solved

[0008] The present invention aims to solve the problems mentioned in the background technology of the invention and provides a method and apparatus capable of predicting and replenishing the amount of catalyst lost in real time to maintain the reaction efficiency of propylene and water during the production of isopropyl alcohol. means of solving the problem

[0009] According to one aspect of the present invention for solving the above problem,

[0010] (S1) A step of feeding a feed stream containing propylene monomer and water into a reactor in the presence of a catalyst to carry out a gas phase reaction;

[0011] (S2) partially condensing the reaction product obtained by the above gas phase reaction in a heat exchanger, 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 system connected online between the heat exchanger and the absorption tower;

[0012] (S3) A step of measuring the pH of the liquid reaction product transferred to the pH system to calculate the catalyst content, and supplementing the reactor with a catalyst corresponding to the calculated content; and

[0013] (S4) A method for producing isopropyl alcohol is provided, comprising the step of separating isopropyl alcohol contained in the gas phase reaction product in the absorption tower by dissolving it in absorbing water.

[0014] Additionally, according to another aspect of the present invention,

[0015] A reactor for reacting propylene monomer and water in the presence of a catalyst;

[0016] A heat exchanger that partially condenses the gaseous reaction product obtained from the above reactor;

[0017] An absorption tower for separating isopropyl alcohol contained in the gaseous reaction product transferred from the above heat exchanger; and

[0018] An apparatus for producing isopropyl alcohol is provided, comprising a pH system connected online between the heat exchanger and the absorption tower. Effects of the invention

[0019] 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 lost catalyst content is calculated based on the results, thereby predicting and replenishing the amount of catalyst lost in real time, so that the reaction efficiency of producing isopropyl alcohol can be maintained.

[0020] In addition, since the online pH measurement described above does not involve a separate sampling process as in conventional offline methods, steam generation is suppressed, making it advantageous in terms of environmental and safety aspects. Brief explanation of the drawing

[0021] Figure 1 schematically illustrates the process of measuring pH in an offline manner after sampling a portion of the reaction product in a conventional isopropyl alcohol manufacturing process. FIG. 2 schematically illustrates a process for manufacturing isopropyl alcohol including an online pH measurement step of a reaction product according to one embodiment of the present invention. FIG. 3 shows an example of applying an online pH measurement system in the manufacturing process of isopropyl alcohol according to one embodiment of the present invention. Specific details for implementing the invention

[0022] Terms and words used in the description and claims of the present invention shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0023] As used herein, the terms 'include' or 'contain' refer to specifying a particular characteristic, area, integer, step, action, element, or component, and do not exclude the addition of other particular characteristic, area, integer, step, action, element, or component.

[0024] As used herein, the term 'stream' may refer to the flow of fluid within a process, and may also refer to the fluid itself flowing within the piping. Specifically, the stream may simultaneously refer to the fluid itself flowing within the piping connecting each device and the flow of the fluid. Additionally, the fluid may include one or more components among gas, liquid, and solid.

[0026] One embodiment of the present invention relates to a method for producing isopropyl alcohol (IPA), specifically comprising a feed supply and reaction step (S1) in the presence of a catalyst, a partial condensation and transfer step of the reaction product (S2), an online pH measurement step (S3) of the liquid reaction product obtained by partial condensation, and a separation step (S4) of isopropyl alcohol from the reaction product.

[0027] FIG. 2 schematically illustrates a process for manufacturing isopropyl alcohol including an online pH measurement step of a reaction product according to an embodiment of the present invention. Hereinafter, a method for manufacturing isopropyl alcohol according to the present invention will be described step-by-step with reference to FIG. 2.

[0028] First, a catalyst is filled into a reactor, and then a feed stream containing propylene monomer and water is supplied to the reactor to carry out a gas phase reaction, thereby obtaining a gas phase stream containing isopropyl alcohol, unreacted propylene monomer, unreacted water, catalyst used in the reaction, and impurities as reaction products (S1).

[0029] In the feed stream 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 the above molar ratio is satisfied, the forward reaction of the equilibrium reaction is promoted and the reverse reaction is prevented from proceeding, thereby increasing the yield of isopropyl alcohol.

[0030] The above reactor can be operated under optimal conditions to efficiently produce isopropyl alcohol through a gas-phase reaction between propylene monomer and water. For example, the operating pressure of the reactor is 30 to 50 kg / cm². 2· g, 35 to 50 kg / cm³ 2· g or 35 to 45 kg / cm² 2·It may be g, and the operating temperature may be 180 to 220 ℃, 185 to 220 ℃, or 185 to 215 ℃.

[0031] The above catalyst is intended to promote the reaction between 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, and an acidic catalyst, such as a phosphate-based catalyst, may be used.

[0032] To increase the efficiency of the gas-phase reaction between propylene and water, the lifespan of the catalyst must be extended; however, to achieve this, some of the phosphoric acid, an active component of the catalyst, may be introduced into the reaction product, potentially leading to phosphoric acid loss within the reactor. To replenish the catalyst lost within the reactor, phosphoric acid must be replenished continuously or discontinuously, and the amount of additional phosphoric acid to be replenished can be determined by analyzing the pH of the effluent after the reaction.

[0033] To this end, in the method for producing isopropyl alcohol according to the present invention, the gaseous reaction product obtained in the reactor is transferred to a heat exchanger to be partially condensed, the uncondensed gaseous reaction product is transferred to an absorption tower, and a portion of the condensed liquid reaction product is transferred to a pH system connected online between the heat exchanger and the absorption tower (S2).

[0034] Specifically, the reaction product obtained under the high pressure and high temperature conditions of the reactor may be partially condensed by heat exchange with the feed stream supplied to the reactor to become a mixture of liquid and gas phases. That is, gas-liquid separation of the reaction product takes place in the heat exchanger.

[0035] For example, the temperature of the feed stream before passing through the heat exchanger may be 90 to 130 ℃, 95 to 130 ℃, or 95 to 125 ℃, and the temperature of the feed stream after passing through the heat exchanger may be 160 to 210 ℃, 165 to 210 ℃, or 170 to 200 ℃. In addition, the temperature of the stream condensed after passing through the heat exchanger may be 100 to 140 ℃, 110 to 140 ℃, or 110 to 130 ℃.

[0036] If necessary, the stream condensed by passing through the heat exchanger can be further condensed using a cooler.

[0037] In this way, by heat-exchanging the reaction product with the feed stream, the energy required to heat the feed stream can be reduced by converting it into a gas-liquid mixture stream and simultaneously preheating the feed stream before supplying it to the reactor.

[0038] The gas-liquid mixture obtained by partial condensation through the above heat exchange can be separated into gaseous and liquid phases within the heat exchanger itself, or separated into gaseous and liquid phases by additionally installing a separator downstream of the heat exchanger.

[0039] Next, the separated gaseous reaction product stream is transferred to an absorption tower, and some of the liquid reaction product is transferred to a pH system connected online between the heat exchanger and the absorption tower to determine the phosphoric acid content of the incoming catalyst and to measure the pH (S3).

[0040] FIG. 3 illustrates an example of applying an online pH measurement system in a manufacturing process of isopropyl alcohol according to an embodiment of the present invention, wherein the pH system may include a pressure reduction unit (10), a gas removal unit (20), a cooling unit (30), a pH measurement unit (40), and a calculation unit (50). When using such an online pH measurement system, a separate sampling process that was conventionally performed for pH measurement of reaction products can be omitted.

[0041] Referring to FIG. 3, a portion of the liquid reaction product stream (100) obtained by partial condensation through heat exchange is transferred to a pressure reduction section (10) of a pH system connected by a line between the heat exchanger and the absorption tower. At this time, the transfer of the liquid reaction product can be carried out through pressure control using valve means installed on the line.

[0042] In the pressure reduction section (10) of the above pH system, since the liquid reaction product is obtained by condensation in the heat exchanger at the rear end of the reactor, the pressure at the rear end of the reactor is approximately 30 kg / cm² 2· Since it represents a high-pressure stream of g, depressurization is performed to match the pressure range required by the pH measuring system for the liquid reaction product.

[0043] For example, a portion of the liquid 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 in a pressure reducing section included in the pH system is set to a range of 1 / 25 to 1 / 35 of the initial pressure, e.g., at an atmospheric pressure level of 1 kg / cm² 2· It can be lowered to g.

[0044] Meanwhile, gas may be generated during the depressurization process of the liquid stream, and if this gas enters the liquid stream, it may cause errors in pH measurements, so gas removal is necessary.

[0045] Accordingly, the depressurized liquid stream can be passed through the gas removal unit (20) of the pH system to remove gas, 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 two or more phases of fluid, such as a knock-out drum, but is not limited thereto.

[0046] The above gas-removed liquid stream is transferred to a cooling section (30) of the pH system, and by supplying a coolant (e.g., refrigerant) at the bottom of the cooling section (30), moving it to the top, and then discharging it, the temperature of the liquid stream can be lowered to a range of 20 to 40°C.

[0047] The above-mentioned cooled liquid stream has its pH measured in a pH-measuring unit (40), and a calculation unit (50) calculates the amount of loss of the phosphate-based catalyst introduced into the reaction mixture from the pH measurement result. By replenishing the reactor with a phosphate-based catalyst corresponding to the calculated amount, the lifespan of the catalyst in the reactor can be increased, thereby securing the final yield of isopropyl alcohol. At this time, the catalyst replenishment can be performed by controlling the pump flow rate of the catalyst supply line connected to the reactor.

[0048] Additionally, the liquid stream that has passed through the cooling unit (3) and the pH-measuring unit (40) can be transferred to a separate separator, such as a knockout drum (KO Drum), and trace amounts of gas components remaining in the separate separator can be discharged together with the gas components removed in the gas removal unit (20).

[0049] Meanwhile, after gas-liquid separation in the heat exchanger, the gaseous reaction product is transferred to an absorption tower, and in the absorption tower, isopropyl alcohol contained in the reaction product is dissolved using absorbing water and separated to the bottom, and a stream containing unreacted propylene monomer contained in the reaction product can be separated to the top (S4).

[0050] In one embodiment of the present invention, the absorption tower may be operated under conditions that effectively separate an upper stream containing unreacted propylene monomer and a lower stream containing isopropyl alcohol, for example, the operating pressure of the absorption tower is 20 to 40 kg / cm² 2· g, 25 to 40 kg / cm³ 2· g or 25 to 35 kg / cm² 2· The range may be g, and the operating temperature may be in the range of 80 to 110 ℃, 90 to 110 ℃, or 90 to 100 ℃.

[0051] The stream containing isopropyl alcohol and water separated at the bottom of the absorption tower is supplied to a purification unit to separate the water, thereby obtaining high-purity isopropyl alcohol. The water separated in the purification unit can be recovered and reused as process water or discharged as wastewater.

[0052] Meanwhile, the stream containing unreacted propylene monomer separated at the top of the absorption tower may contain impurities such as inert gases, and the unreacted propylene monomer may pass through an inert gas removal column to be used again for the production of isopropyl alcohol.

[0053] If necessary, the method for producing isopropyl alcohol according to the present invention may additionally install and use devices such as a distillation column, a condenser, a reboiler, a valve, a pump, a separator, and a mixer.

[0054] 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 based on the results, thereby allowing the amount of catalyst lost to be predicted and replenished in real time, so as to maintain the yield of isopropyl alcohol.

[0055] In addition, since the online pH measurement described above does not involve a separate sampling process as in conventional offline methods, steam generation is suppressed, making it advantageous in terms of environmental and safety aspects.

[0056] The method for producing isopropyl alcohol according to the present invention as described above can be performed using a device including an online connected pH system.

[0057] Accordingly, the present invention provides an apparatus for producing isopropyl alcohol comprising: a reactor for reacting a propylene monomer and water in the presence of a catalyst; a heat exchanger for partially condensing a gaseous reaction product obtained from the reactor; an absorption tower for separating isopropyl alcohol contained in the gaseous reaction product transferred from the heat exchanger; and a pH system connected online between the heat exchanger and the absorption tower.

[0058] In the above manufacturing device, the description of the configuration that overlaps with the previous manufacturing method is the same.

Claims

Claim 1 (S1) a step of supplying a feed stream containing propylene monomer and water in the presence of a catalyst to a reactor to carry out a gas phase reaction; (S2) a step of partially condensing the reaction product obtained by the gas phase reaction in a heat exchanger, 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 system connected online between the heat exchanger and the absorption tower; (S3) a step of measuring the pH of the liquid phase reaction product transferred to the pH system to calculate the catalyst content and replenishing the reactor with a catalyst corresponding to the calculated content; and (S4) a step of separating the isopropyl alcohol contained in the gas phase reaction product in the absorption tower by dissolving it in absorbing water. A method for producing isopropyl alcohol. Claim 2 A method for producing isopropyl alcohol according to claim 1, wherein the gaseous reaction product is a gaseous stream comprising isopropyl alcohol, unreacted propylene monomer, unreacted water, catalyst used in the reaction, and impurities. Claim 3 A method for producing isopropyl alcohol according to claim 1, wherein the catalyst comprises a phosphate-based catalyst. Claim 4 A 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 a feed stream supplied to the reactor. Claim 5 A 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 an online pH system via pressure control. Claim 6 A method for producing isopropyl alcohol according to claim 1, wherein the liquid reaction product transferred to the pH system undergoes a process of depressurization, gas removal, and cooling, and then the pH is measured. Claim 7 A method for producing isopropyl alcohol according to claim 6, wherein the pressure reduction of the liquid reaction product is performed in the range of 1 / 25 to 1 / 35 of the initial pressure transferred to the pH system. Claim 8 A method for producing isopropyl alcohol according to claim 6, wherein the gas removal of the liquid reaction product is the removal of gas generated during the depressurization process. Claim 9 A method for producing isopropyl alcohol according to claim 6, wherein the cooling of the reaction product is performed at a temperature of 20 to 40°C using a refrigerant. Claim 10 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 the gaseous reaction product obtained from the reactor; an absorption tower for separating isopropyl alcohol contained in the gaseous reaction product transferred from the heat exchanger; and a pH system connected online between the heat exchanger and the absorption tower. Claim 11 In item 10, the above pH system is an apparatus for producing isopropyl alcohol comprising a pressure reduction unit, a gas removal unit, a cooling unit, a pH measuring unit, and a calculation unit.

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