Method for manufacturing acid gas absorber and acid gas produced by the same

Abstract

The present invention relates to a method for manufacturing a mixed absorbent without a separate purification process in order to produce an absorbent having excellent acidic gas absorption capacity, including carbon dioxide, and a fast reaction rate through an efficient process, and to an absorbent manufactured by said method. The acidic gas absorbent of the present invention not only has excellent acidic gas absorption capacity and a fast reaction rate, but also adopts an efficient process that omits the separation and purification processes of reactants for the manufacture of the absorbent, thereby making the process simple and economical.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing an acidic gas absorbent and an absorbent manufactured by the same method. More specifically, it relates to a method for manufacturing an absorbent with excellent absorption capacity for acidic gases, including carbon dioxide, and a fast reaction rate through an efficient process, by manufacturing the absorbent solely through a mixing process without separate additional processes such as purification or addition, and to the absorbent manufactured by the same method. Background Technology

[0003] The present invention relates to a method for manufacturing an acidic gas absorbent and an absorbent manufactured by the same method. More specifically, it relates to a method for manufacturing an absorbent with excellent absorption capacity for acidic gases, including carbon dioxide, and a fast reaction rate through an efficient process, by manufacturing the absorbent solely through a mixing process without separate additional processes such as purification or addition, and to the absorbent manufactured by the same method.

[0004] Carbon dioxide (CO2) emissions, which had been increasing gradually since the Industrial Revolution, surged rapidly following the 1940s when full-scale industrial development began, driven by the increased use of fossil fuels. Notably, CO2 emissions reached a new record high exceeding 36.8 Gt in 2022. In modern times, CO2 has become a representative greenhouse gas causing global warming and climate change, and it now impacts human survival. Therefore, reducing CO2 is critical for the future and survival of humanity. CO2 capture is the technology capable of reducing CO2 the most in the short to medium term. Adsorption, absorption, membranes, and cryogenic separation are currently used CO2 capture technologies capable of separating CO2 from flue gas. In particular, the chemical absorption method using alkanolamines is the most advanced and commercially viable technology, offering advantages such as high CO2 reactivity, high absorption rates, and simple process design under low CO2 concentration conditions in flue gas. However, there are still difficulties in applying this to larger-scale processes due to issues such as the high regeneration energy required for the absorbent, degradation of the absorbent, and corrosion of process equipment. The chemical absorption method using alkanolamines involves a circulation process of absorption and regeneration of the absorbent in the absorption tower and stripping tower. In the absorption tower, which operates at a low temperature (~50°C), the absorbent reacts with CO2 to produce a CO2-rich solution. This solution then moves to the stripping tower, where thermal regeneration of the CO2-rich solution occurs at a high temperature (~120°C). This process produces an absorbent with separated CO2 and a CO2-deficient solution, which then returns to the absorption tower for circulation. A reboiler is required to maintain the temperature of the stripping tower, and this process accounts for approximately 80% of the total process cost. Therefore, reducing the energy required for the absorbent regeneration process is a critical factor for the expansion and application of the process.

[0005] Various methods for the separation and recovery of acidic gases, including carbon dioxide, such as absorption, adsorption, membrane separation, and cryogenic methods, are available, and absorption methods suitable for separating large volumes and low concentrations of gases are being studied extensively. Ethanolamine is used to capture carbon dioxide using the absorption method, and ethanolamines include monoethanolamine (MEA), a primary amine; diethanolamine (DEA), a secondary amine; triethanolamine (TEA), N-methyl diethanolamine (MDEA), a tertiary amine; and triisopropanolamine (TIPA).

[0006] Among these, using monoethanolamine or diethanolamine, which have the highest basicity and smallest equivalent weight, as the absorbent results in a fast reaction rate, but a large amount of energy is consumed for carbon dioxide separation. Additionally, a large amount of absorbent solution is used, and the solution causes corrosion of the equipment. In the case of MDEA, while it has low corrosiveness and regeneration heat, it has the disadvantage of a low absorption rate.

[0007] To solve these problems, Korean Registered Patent No. 1746561 [Carbon Dioxide Absorbent and Method for Regenerating Carbon Dioxide Absorbent] discloses a technology for a diamine compound carbon dioxide absorbent containing primary and tertiary amines. However, there is still a problem in that the absorption rate is slow and an additional process of adding an additional solvent is required.

[0008] Accordingly, based on this perspective, the present invention aims to provide an efficient method for manufacturing an acidic gas absorbent using only a synthesis process without additional processes such as a separate purification process or additional processes, and an absorbent manufactured by the same method. Prior art literature

[0010] Republic of Korea Registered Patent No. 1746561 The problem to be solved

[0011] Accordingly, the technical objective of the present invention is to provide an efficient method for manufacturing an acidic gas absorbent that not only has excellent acidic gas absorption capacity and a fast reaction rate, but also manufactures the absorbent solely through a synthesis process without additional processes such as a separate purification process or additional steps, and to provide the absorbent manufactured by said method.

[0012] However, the technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0014] To achieve the above technical objective, one aspect of the present invention is a method for manufacturing an acidic gas absorbent, the method comprising: a step of supplying water and ammonia to a first mixer to produce a first mixture; a step of supplying the first mixture from the first mixer to a second mixer through a first mixer discharge pipe and simultaneously supplying ethylene oxide to the second mixer to form a second mixture; a step of supplying the second mixture from the second mixer to a reactor through a second mixer discharge pipe and reacting the second mixture under predetermined temperature and pressure conditions to form a third mixture; a step of supplying the third mixture from the reactor through a reactor discharge pipe to a first separator equipped with a distillation tower function to separate it into unreacted ammonia, steam, and a fourth mixture; a step of recovering the unreacted ammonia and steam in the first separator to the first mixer through a first separator distillation tower connecting pipe, and supplying the fourth mixture through a first separator discharge pipe to a second separator equipped with a distillation tower function to separate it into unreacted water and a fifth mixture. The present invention provides a method for manufacturing an acidic gas absorbent, comprising the steps of recovering a portion of the unreacted water in the second separator as steam through the second separator distillation column connecting pipe to the first mixer, and obtaining the fifth product as an acidic gas absorbent through the second separator discharge pipe, wherein the molar ratio of the ammonia supplied to the first mixer, the unreacted ammonia recovered through the first separator distillation column connecting pipe, and the ethylene oxide supplied to the second mixer is 5:1 to 10:1, and the predetermined temperature and pressure conditions are 50 to 70 ℃ and 3 to 15 bar, respectively.

[0015] The temperature range of the first separator may be 50 to 170 ℃, and the pressure range may be 2 to 6 bar.

[0016] The temperature range of the second separator may be 80 to 150 ℃, and the pressure range may be 0 to 1.2 bar.

[0018] Another aspect of the present invention provides an acidic gas absorbent manufactured by the method of any one of claims 1 to 3.

[0019] The above acidic gas absorbent may be characterized by comprising 10 to 60 wt% monoethanolamine, 20 to 70 wt% diethanolamine, 15 to 60 wt% triethanolamine, and 10 to 40 wt% water based on the total weight.

[0021] Another aspect of the present invention provides a method for capturing carbon dioxide using an acidic gas absorbent, comprising the steps of: preparing an aqueous solution containing an acidic gas absorbent prepared by the method of claim 1 (S100); capturing carbon dioxide using the aqueous solution, wherein the reaction heat generated by the reaction between the aqueous solution and the carbon dioxide is 74 KJ / mol-CO2 or less (S200).

[0022] In the above S100 step, the aqueous solution may be characterized by containing 50 to 60 wt% of the acidic gas absorbent of claim 4.

[0023] The above S200 step may be characterized by capturing carbon dioxide in a temperature range of 30 to 50 ℃ and a pressure range of 1.5 bar or less.

[0024] In the above S200 step, the acidic gas absorbent may be characterized by having an absorption rate of 0.0024 mol CO2 / min or more after 10 minutes have elapsed since exposure to carbon dioxide.

[0025] After the above S200 step, it may further include a step (S300) of desorbing and regenerating the captured carbon dioxide.

[0026] In the above S300 step, the acidic gas absorbent may be characterized by having a maximum desorption rate of 0.0020 mol CO2 / min or more and 0.0025 mol CO2 / min or less.

[0028] Another aspect of the present invention is a method for manufacturing an acidic gas absorbent, the method comprising: a step of supplying water and ammonia to a first reactor to produce a first reactant; a step of supplying ethylene oxide to a second reactor simultaneously with the first reactant through a supply pipe connected to a first connecting pipe that supplies the first reactant of the first reactor to a second reactor to form a second reactant; a step of supplying the second reactant of the second reactor through a second connecting pipe to a third reactor equipped with a distillation tower function to separate it into unreacted ammonia and a third reactant; a step of recovering the unreacted ammonia in the third reactor to the first reactor through a third connecting pipe, and supplying the third reactant to a fourth reactor equipped with a distillation tower function through a fourth connecting pipe to separate it into unreacted water and a fourth reactant. The present invention provides a method for manufacturing an acidic gas absorbent, comprising the steps of recovering unreacted material in the fourth reactor to the first reactor through a fifth connecting pipe and obtaining the fourth reactant as an acidic gas absorbent through the fourth reactor discharge pipe, wherein the molar ratio of the total ammonia supplied to the first reactor and the unreacted ammonia recovered through the third connecting pipe to the ethylene oxide supplied through the supply pipe is 5:1 to 10:1.

[0029] The above second reactor may be characterized in that the temperature range is 50 to 70 ℃ and the pressure range is 0.5 to 1.5 MPa.

[0031] Another aspect of the present invention provides an acid gas absorbent manufactured by the method of claim 12 or 13.

[0032] The above acidic gas absorbent may be characterized by comprising 20 to 70 wt% monoethanolamine, 10 to 20 wt% diethanolamine, and 5 to 75 wt% triethanolamine based on the total weight. Effects of the invention

[0034] According to one aspect of the present invention, the acid gas absorbent of the present invention not only has excellent acid gas absorption capacity and a fast reaction rate, but also adopts an efficient process that eliminates additional processes such as separation and purification of reactants for the manufacture of the absorbent, thereby making the process simple and economical.

[0035] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention. Brief explanation of the drawing

[0037] FIG. 1 is a conceptual diagram illustrating a process for manufacturing a mixed absorbent using an aqueous ammonia solution and ethylene oxide according to one embodiment of the present invention. FIG. 2 is a conceptual diagram illustrating a process for manufacturing a mixed absorbent using an aqueous ammonia solution and ethylene oxide according to one embodiment of the present invention. FIG. 3 shows the carbon dioxide adsorption curve of an acidic gas absorbent according to one embodiment of the present invention. FIG. 4 shows the carbon dioxide absorption capacity (absorption rate) of an acidic gas absorbent according to one embodiment of the present invention. FIG. 5 shows the absorption rate of an acidic gas absorbent after 10 minutes of exposure to carbon dioxide, according to one embodiment of the present invention. FIG. 6 shows the carbon dioxide desorption curve of an acid gas absorbent according to one embodiment of the present invention. FIG. 7 shows the carbon dioxide desorption ability (desorption rate) of an acidic gas absorbent according to one embodiment of the present invention. FIG. 8 shows the maximum desorption rate of the acid gas absorbent according to one embodiment of the present invention. FIG. 9 is data related to the absorption and desorption (regeneration) of the acid gas absorbent according to one embodiment of the present invention. Figure 10 shows a schematic diagram of an absorption equilibrium device fabricated to measure the carbon dioxide absorption capacity of an acid gas absorbent. Specific details for implementing the invention

[0038] The present invention will be described in more detail below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0039] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0040] The terms used herein are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0041] In describing the present invention, if it is determined that a detailed description of related known configurations or functions could obscure the essence of the invention, such detailed description may be omitted.

[0043] The first aspect of the present invention relates to a method for manufacturing an acidic gas absorbent, the method comprising: a step of supplying water and ammonia to a first mixer to produce a first mixture; a step of supplying the first mixture from the first mixer to a second mixer through a first mixer discharge pipe and simultaneously supplying ethylene oxide to the second mixer to form a second mixture; a step of supplying the second mixture from the second mixer to a reactor through a second mixer discharge pipe and reacting the second mixture under predetermined temperature and pressure conditions to form a third mixture; a step of supplying the third mixture from the reactor through a reactor discharge pipe to a first separator equipped with a distillation tower function to separate it into unreacted ammonia, steam, and a fourth mixture; a step of recovering the unreacted ammonia and steam in the first separator to the first mixer through a first separator distillation tower connecting pipe, and supplying the fourth mixture to a second separator equipped with a distillation tower function through a first separator discharge pipe to separate it into unreacted water and a fifth mixture. The present invention provides a method for manufacturing an acidic gas absorbent, comprising the steps of recovering a portion of the unreacted water in the second separator as steam through the second separator distillation column connecting pipe to the first mixer, and obtaining the fifth product as an acidic gas absorbent through the second separator discharge pipe, wherein the molar ratio of the ammonia supplied to the first mixer, the unreacted ammonia recovered through the first separator distillation column connecting pipe, and the ethylene oxide supplied to the second mixer is 5:1 to 10:1, and the predetermined temperature and pressure conditions are 50 to 70 ℃ and 3 to 15 bar, respectively.

[0045] Hereinafter, a method for manufacturing an acid gas absorbent according to the first aspect of the present invention is described.

[0047] In one embodiment of the present invention, a primary amine such as monoethanolamine (MEA) and a secondary amine such as diethanolamine (DEA) generally follow the following mechanism.

[0048] CO2 + 2RNH2 ↔ RNHCOO - + RNH3 +

[0049] Tertiary amines such as triethanolamine (TEA) are unstable in the above reaction pathway and therefore follow the reaction mechanism below.

[0050] CO2 + R3N + H2O ↔ R3NH + + HCO3 -

[0051] Therefore, primary and secondary amines require two amines to absorb one carbon dioxide, while tertiary amines require one amine to absorb one carbon dioxide, thus exhibiting twice the absorption capacity compared to primary or secondary amines. An absorbent composed of a mixture of primary, secondary, and tertiary amines demonstrates high-efficiency carbon dioxide absorption. To improve the method of preparing and mixing each of the primary, secondary, and tertiary amines to create such a mixed absorbent, an aqueous ammonia solution and ethylene oxide are synthesized. In the present invention, intermediate amine products are adopted without a separate purification process during synthesis, thereby obtaining an economical separation material for an acidic gas capture process through a simpler process than amine products produced after final separation and purification. The acidic gases of the present invention include, but are not limited to, carbon dioxide, hydrogen sulfide, and sulfur oxides. The present invention will be described in detail below with reference to the drawings.

[0052] In one embodiment of the present invention, FIG. 1 is a conceptual diagram illustrating a process for manufacturing a mixed absorbent using an aqueous ammonia solution and ethylene oxide according to another embodiment of the present invention. The present invention is a method for manufacturing an acidic gas absorbent, comprising the steps of: supplying water and ammonia to a first mixer (100) to produce a first mixture; supplying the first mixture from the first mixer to a second mixer (200) through a first mixer discharge pipe (101) and simultaneously supplying ethylene oxide to the second mixer to form a second mixture; supplying the second mixture from the second mixer to a reactor (300) through a second mixer discharge pipe (102) and reacting the second mixture under predetermined temperature and pressure conditions to form a third mixture; and supplying the third mixture from the reactor to a first separator (400) equipped with a distillation tower function through a reactor discharge pipe (103) to separate it into unreacted ammonia, water vapor, and a fourth mixture. The method includes the step of recovering unreacted ammonia and water vapor in the first separator through the first separator distillation tower connecting pipe (104) to the first mixer, and supplying the fourth mixture to the second separator (500) equipped with a distillation tower function through the first separator discharge pipe (105) to separate it into unreacted water and a fifth mixture; and the step of recovering a portion of the unreacted water in the second separator as water vapor through the second separator distillation tower connecting pipe (106) to the first mixer, and obtaining the fifth product as an acidic gas absorbent through the second separator discharge pipe (107).

[0053] In one embodiment of the present invention, the molar ratio of the ammonia supplied to the first mixer, the unreacted ammonia recovered through the first separator distillation column connecting pipe, and the ethylene oxide supplied to the second mixer is 5:1 to 10:1. Ammonia and water are supplied from outside the first mixer, and the operating conditions are maintained at room temperature and atmospheric pressure. Since ethylene oxide is an explosive substance and is dangerous to handle if there is any material remaining after reacting with ammonia, it is preferable to add an excess amount of ammonia compared to ethylene oxide.

[0054] In one embodiment of the present invention, the ethylene oxide and the ammonia solution in the reactor are reacted such that the ammonia is in excess reaction equivalent ratio in the reaction equivalent ratio of ethylene oxide to ammonia, so that a sufficient reaction takes place. The predetermined temperature and pressure conditions of the reactor are 50 to 70°C and 3 to 15 bar, respectively.

[0055] In one embodiment of the present invention, the temperature range of the first separator is 50 to 170°C, and the pressure range is 2 to 6 bar. The first separator is primarily intended to separate ammonia from an amine solution synthesized in a reactor. An excess ammonia solution is injected to maximize the reaction of ethylene glycol in the upper reactor, and unreacted ammonia is generated and separated. The separated ammonia gas and some water vapor are recirculated to the first mixer.

[0056] In one embodiment of the present invention, the temperature range of the second separator is 80 to 150°C and the pressure range is 0 to 1.2 bar. The second separator is intended to primarily remove water from the synthesized amine mixed solution, but can also completely separate ammonia that was not completely separated in the first separator.

[0058] A second aspect of the present invention provides an acidic gas absorbent manufactured by the method of any one of claims 1 to 3.

[0059] Detailed explanations have been omitted for parts that overlap with the first aspect of the present invention; however, the content described in the first aspect of the present invention may be applied equally even if such explanations are omitted in the second aspect.

[0060] In one embodiment of the present invention, the acidic gas absorbent prepared by the method of any one of claims 1 to 3 may comprise, based on the total weight, 10 to 60 wt% monoethanolamine, 20 to 70 wt% diethanolamine, 15 to 60 wt% triethanolamine, and 10 to 40 wt% water as a synthetic amine mixed solution.

[0062] The third aspect of the present invention provides a method for capturing carbon dioxide using an acidic gas absorbent, comprising the steps of: preparing an aqueous solution containing an acidic gas absorbent prepared by the method of claim 1 (S100); capturing carbon dioxide using the aqueous solution, wherein the reaction heat generated by the reaction between the aqueous solution and the carbon dioxide is 74 KJ / mol-CO2 or less (S200).

[0063] Detailed descriptions of parts overlapping with the first and second aspects of the present invention have been omitted, but the descriptions of the first and second aspects of the present invention may be applied equally to the third aspect even if such descriptions are omitted.

[0065] Hereinafter, a carbon dioxide capture method using an acidic gas absorbent according to the third aspect of the present invention will be described in detail.

[0067] First, in one embodiment of the present invention, in step S100, the aqueous solution may contain 50 to 60 wt% of the acidic gas absorbent of claim 4. If the amount is less than the above range, sufficient adsorption of carbon dioxide may not be achieved.

[0068] In one embodiment of the present invention, the S200 step may involve capturing carbon dioxide in a temperature range of 30 to 50 ℃ and a pressure range of 1.5 bar or less, and in the S200 step, the acidic gas absorbent may have an absorption rate of 0.0024 mol CO2 / min or more after 10 minutes have elapsed since exposure to carbon dioxide. The results are shown in FIG. 5, and it can be confirmed that the absorption rate is relatively low when the content of the acidic gas absorbent in the aqueous solution is insufficient.

[0069] In one embodiment of the present invention, after step S200, a step (S300) of desorbing and regenerating the captured carbon dioxide is further included; and in step S300, the acidic gas absorbent may have a maximum desorption rate of 0.0020 mol CO2 / min or more and 0.0025 mol CO2 / min or less. The results are shown in FIG. 8, and it can be confirmed that when the content of the acidic gas absorbent in the aqueous solution is insufficient, the desorption rate is relatively low.

[0071] The fourth aspect of the present invention relates to a method for manufacturing an acidic gas absorbent, wherein the method comprises the steps of: supplying water and ammonia to a first reactor to produce a first reactant; supplying ethylene oxide to a second reactor simultaneously with the first reactant through a supply pipe connected to a first connecting pipe that supplies the first reactant of the first reactor to a second reactor, thereby forming a second reactant; supplying the second reactant of the second reactor through a second connecting pipe to a third reactor equipped with a distillation tower function to separate it into unreacted ammonia and a third reactant; recovering the unreacted ammonia in the third reactor to the first reactor through a third connecting pipe, and supplying the third reactant to a fourth reactor equipped with a distillation tower function through a fourth connecting pipe to separate it into unreacted water and a fourth reactant. The present invention provides a method for manufacturing an acidic gas absorbent, comprising the steps of recovering unreacted material in the fourth reactor to the first reactor through a fifth connecting pipe and obtaining the fourth reactant as an acidic gas absorbent through the fourth reactor discharge pipe, wherein the molar ratio of the total ammonia supplied to the first reactor and the unreacted ammonia recovered through the third connecting pipe to the ethylene oxide supplied through the supply pipe is 5:1 to 10:1.

[0072] Detailed descriptions of parts overlapping with the first to third aspects of the present invention have been omitted; however, the descriptions of the first to third aspects of the present invention may be applied equally to the fourth aspect even if such descriptions are omitted.

[0074] Hereinafter, a method for manufacturing an acid gas absorbent according to the fourth aspect of the present invention will be described in detail.

[0076] In one embodiment of the present invention, the ethylene oxide and the ammonia solution in the second reactor are reacted such that the ammonia is in excess reaction equivalent ratio in the reaction equivalent ratio of ethylene oxide to ammonia, so that a sufficient reaction takes place. The temperature range of the second reactor may be 50 to 70 ℃, and the pressure range may be 0.5 to 1.5 MPa.

[0078] The fifth aspect of the present invention provides an acid gas absorbent manufactured by the method of claim 12 or 13.

[0079] Detailed descriptions have been omitted for parts that overlap with the first through fourth aspects of the present invention; however, the descriptions provided for the first through fourth aspects of the present invention may be applied equally to the fifth aspect even if such descriptions are omitted.

[0080] In one embodiment of the present invention, the acidic gas absorbent prepared by the method of claim 12 or 13 may comprise 20 to 70 wt% monoethanolamine, 10 to 20 wt% diethanolamine, and 5 to 75 wt% triethanolamine based on the total weight.

[0082] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0083] Example 1: Average composition according to the absorbent manufacturing process

[0084] When an acidic gas absorbent is manufactured using the manufacturing method described above, the composition ratio of each component converges within a certain range. The results of manufacturing using the method described above in Figure 1 and the description below are as shown in Table 1.

[0086] Order 1 2 3 4 5 average(%) MEA 25.9 22.6 20.4 20.1 19.7 21.7 DEA 34.6 33.5 34.3 35.1 34.9 34.5 TEA 22.9 27.2 28.1 26.7 27.6 26.5 H2O 16.6 16.7 17.2 18.1 17.8 17.3 total(%) 100.0 100.0 100.0 100.0 100.0 100.0

[0087] This mixed solution is an intermediate product of the amine production process. Since the process is simpler and the cost is lower than that of amine products produced after final separation and purification, it functions as a separation material for acid gas capture processes containing carbon dioxide, hydrogen sulfide, and sulfur oxides, and can significantly reduce process operating costs compared to conventional simple synthesis.

[0089] Example 2: Carbon dioxide capture and desorption method using an acid gas absorbent

[0090] Carbon dioxide capture operations were carried out using an acid gas absorbent prepared by the manufacturing method described above. After preparing aqueous solutions containing 20% ​​(20% acid gas absorbent + 80% water), 30%, 40%, 50%, and 60% acid gas absorbent, gas-liquid experiments were conducted, and the results are as follows. At this time, the conditions for adsorption and desorption experiments are as shown in Table 2 below.

[0091] Adsorption Desorption Temperature 40 ℃ Temperature 90 ℃ Pressure 1 Bar Pressure 1 Bar Flow rate 588 cc / min Flow rate - cc / min N2 500 cc / min N2 500 cc / min CO2 88.3 cc / min CO2 - cc / min

[0092] At this time, a schematic diagram of an absorption equilibrium device fabricated to measure the carbon dioxide absorption capacity (absorption rate) of an acid gas absorbent is shown in Fig. 10. This equilibrium device measures the amount of carbon dioxide absorbed using the principle of vapor-liquid equilibrium and is broadly divided into a gas supply section, a reaction section, and a data recording section. The gas supply section consists of a gas supply unit (bomb) and a gas cylinder, and the gas supplied from the supply unit passes through a filter and is stored in a gas supplying cylinder. At this time, the supplying cylinder is installed inside a constant temperature bath to maintain a constant temperature. In addition, a pressure transducer (Sensys pressure transmitter Co., N / M: PSHFC100KCAG, 0~100 bar, error range ±0.005%) and a temperature indicator (temperature indicator, -40~180℃, K-type thermocouple, error range ±0.1℃) were installed in the supply tank to accurately determine the temperature and pressure of the gas supplied to the reactor. The supply tank has a volume of 220cc and consists of four units, allowing for many absorption experiments to be performed simultaneously.

[0093] The reaction section consists of a reactor in which an acidic gas absorbent absorbs carbon dioxide. The reactor has a height of 39 mm, an inner diameter of 48 mm, a thickness of 7 mm, and an internal volume of 73 cc. The reactor is installed inside a constant temperature bath equipped with an immersing heater, allowing for the maintenance of a constant temperature. Similar to the feed tank, pressure and temperature sensors were installed inside the reactor to ensure accurate pressure and temperature measurements. A vacuum pump was installed outside the reactor to maintain a vacuum at the beginning of the experiment. Additionally, to promote gas-liquid reactions, a magnetic bar was placed inside the reactor, and a magnetic stirrer was installed at the bottom of the constant temperature bath to drive it. Four reactors were installed inside the constant temperature bath. The data recording section consists of a data collection device that gathers data from the pressure and temperature sensors, and a computer equipped with monitoring software to record experimental results based on changes in conditions in the feed tank and reactor. Consequently, changes in temperature and pressure over time and under experimental conditions can be monitored in real time.

[0094] Prior to the experiment to measure the carbon dioxide absorption rate and absorption speed using an acid gas absorbent, residual gases inside the supply tank and the reactor containing the sample were completely removed using a vacuum pump. Subsequently, the thermostats of the supply tank and the reactor were raised to the respective experimental temperatures. Carbon dioxide was then injected into the supply tank to the set pressure and maintained for 30 minutes to ensure a constant temperature. Afterward, the valve connecting the supply tank and the storage tank was opened to supply carbon dioxide at the set pressure to the reactor. Once the set pressure was reached, the valve was closed, and the temperature and pressure inside the reactor were measured as the experimental time elapsed. As the experimental time progressed, the carbon dioxide inside the reactor was absorbed by the acid gas absorbent, causing the pressure to decrease; the absorption experiment was terminated when there was finally no change in pressure inside the reactor. A magnetic stirrer installed at the bottom of the reactor was used to increase the contact area between the carbon dioxide and the acid gas absorbent, and the stirring speed was maintained at a constant 250 rpm to ensure consistent contact conditions during each experiment.

[0095] Prior to calculating the absorption rate, the volumes of the supply tank, supply line, and storage tank required for the calculation were measured. The Allpros program was used to calculate the carbon dioxide absorption rate based on pressure changes. The Allpros program can simulate the thermodynamic properties of various gases relatively accurately using dozens of proprietary parameters. By using the Allpros program to obtain carbon dioxide density values ​​under temperature and pressure conditions, the amount of carbon dioxide absorbed is calculated by determining the density change based on the pressure difference between the initial injection pressure and the final pressure at which the absorption reaction reaches equilibrium.

[0096] The following method was used to calculate the carbon dioxide absorption rate using an acid gas absorbent. First, the volume of carbon dioxide injected into the reactor was calculated by subtracting the volume of the injected acid gas absorbent from the volume of the reactor, using the method shown in Chemical Formula 1 below.

[0097]

[0098] Here w is the molecular weight of carbon dioxide, c Assuming that is the number of moles per unit volume, it can be represented by the following chemical formula 2.

[0099]

[0100] also c 1 is under the conditions prior to injecting carbon dioxide into the reactor, and c 2 It is represented by the following chemical formula 3 when the condition is that equilibrium is completely reached after carbon dioxide is injected into the reactor.

[0101]

[0102] n 1 is the number of moles of initial carbon dioxide injected into the reactor, and n 2 Since is the number of moles of carbon dioxide remaining in the reactor after reacting with the acid gas absorbent n 1 at n 2 The value obtained by subtracting is the number of moles of absorbed carbon dioxide, expressed by Chemical Formula 4.

[0103]

[0104] Finally, to calculate the mole fraction of the acid gas absorbent into which carbon dioxide was absorbed, the number of moles of the acid gas absorbent was calculated as in Chemical Formula 5, and then the mole fraction of carbon dioxide absorbed by the acid gas absorbent as in Chemical Formula 6 was calculated.

[0105]

[0106]

[0108] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0109] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0111] 10. First reactor 11. First connector 12. Second connector 13. Third connector 14. 4th connector 15. 5th connector 16. 4th Reactor Discharge Pipe 20. Second reactor 30. Third reactor 40. Fourth reactor 100. First mixer 101. First mixer discharge pipe 102. Second mixer discharge pipe 103. Reactor discharge pipe 104. First Separator Distillation Column Connecting Pipe 105. First separator discharge pipe 106. Second Separator Distillation Column Connecting Pipe 107. Second separator discharge pipe 200. Second mixer 300. Reactor 400. First separator 500. Second separator

Claims

Claim 1 A method for manufacturing an acid gas absorbent comprises: a first step of supplying water and ammonia to a first mixer to produce a first mixture; a second step of supplying the first mixture from the first mixer to a second mixer through a first mixer discharge pipe and simultaneously supplying ethylene oxide to the second mixer to form a second mixture; a third step of supplying the second mixture from the second mixer to a reactor through a second mixer discharge pipe and reacting the second mixture under predetermined temperature and pressure conditions to form a third mixture; a fourth step of supplying the third mixture from the reactor through a reactor discharge pipe to a first separator equipped with a distillation tower function to separate it into unreacted ammonia, steam, and a fourth mixture; and a fifth step of recovering the unreacted ammonia and steam in the first separator to the first mixer through a first separator distillation tower connecting pipe and supplying the fourth mixture through a first separator discharge pipe to a second separator equipped with a distillation tower function to separate it into unreacted water and a fifth mixture. A method for manufacturing an acidic gas absorbent, comprising: a sixth step of recovering a portion of the unreacted water in the second separator as steam through the second separator distillation column connecting pipe to the first mixer, and obtaining the fifth mixture as an acidic gas absorbent through the second separator discharge pipe; and a seventh step of preparing an aqueous solution containing the manufactured acidic gas absorbent; wherein the molar ratio of the sum of the ammonia supplied to the first mixer and the unreacted ammonia recovered through the first separator distillation column connecting pipe to the ethylene oxide supplied to the second mixer is 5:1 to 10:1, the predetermined temperature and pressure conditions are 50 to 70 ℃ and 3 to 15 bar, respectively, and the aqueous solution contains 50 to 60 wt% of the acidic gas absorbent. Claim 2 A method for manufacturing an acidic gas absorbent according to claim 1, characterized in that the temperature range of the first separator is 50 to 170 ℃ and the pressure range is 2 to 6 bar. Claim 3 A method for manufacturing an acidic gas absorbent according to claim 1, characterized in that the temperature range of the second separator is 80 to 150 ℃ and the pressure range is 0 to 1.2 bar. Claim 4 delete Claim 5 A method for manufacturing an acidic gas absorbent according to claim 1, characterized in that the acidic gas absorbent comprises 10 to 55 wt% monoethanolamine, 20 to 65 wt% diethanolamine, 15 to 60 wt% triethanolamine, and 10 to 40 wt% water based on the total weight. Claim 6 A method for capturing carbon dioxide using an acidic gas absorbent, comprising the step (S200) of capturing carbon dioxide using an aqueous solution containing an acidic gas absorbent prepared by the method of claim 1, wherein the reaction heat generated by the reaction between the aqueous solution and the carbon dioxide is 74 KJ / mol-CO2 or less. Claim 7 delete Claim 8 A method for capturing carbon dioxide using an acidic gas absorbent, wherein, in claim 6, the S200 step captures carbon dioxide in a temperature range of 30 to 50 ℃ and a pressure range of 1.5 bar or less. Claim 9 A method for capturing carbon dioxide using an acidic gas absorbent, wherein, in the above S200 step, the acidic gas absorbent has an absorption rate of 0.0024 mol CO2 / min or higher after 10 minutes have elapsed since exposure to carbon dioxide. Claim 10 A carbon dioxide capture method using an acidic gas absorbent, characterized in that, in claim 6, after the above S200 step, it further includes a step (S300) of desorbing and regenerating the captured carbon dioxide. Claim 11 A method for capturing carbon dioxide using an acidic gas absorbent, characterized in that, in the above S300 step, the maximum desorption rate of the acidic gas absorbent is 0.0020 mol CO2 / min or more and 0.0025 mol CO2 / min or less. Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 delete

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