KR20230131557A - System for mineralization of co2 using seawater reverse osmosis brine and membrane contactor - Google Patents

Abstract

The disclosed carbon dioxide mineralization system includes a reaction unit including a hollow fiber separation membrane; a gas providing unit providing flue gas containing carbon dioxide within the hollow fiber separation membrane; a liquid provider providing brine generated in a seawater desalination process to a space surrounding the outer surface of the hollow fiber membrane; and a carbonate separation unit that separates carbonate from the brine that has passed through the reaction unit.

Description

Carbon dioxide mineralization system using seawater desalination brine and membrane contactor {SYSTEM FOR MINERALIZATION OF CO2 USING SEAWATER REVERSE OSMOSIS BRINE AND MEMBRANE CONTACTOR}

The present invention relates to a mineralization system for carbon dioxide. More specifically, it relates to a carbon dioxide mineralization system using seawater desalination brine and a membrane contactor.

Recently, carbon capture, utilization and storage technologies have been proposed to reduce carbon dioxide emitted from the use of fossil fuels.

The currently widely used industrial carbon dioxide capture method is amine scrubbing, which utilizes the Lewis acid-base interaction between carbon dioxide and amine groups in an aqueous solution. However, this process has the disadvantage that the energy penalty for regeneration of the amine solution is large because the heat capacity of the amine solution is similar to that of water.

In contrast, direct CO ₂ mineralization has the advantage of processing carbon dioxide more effectively in a single process. Through this system, carbon dioxide can be reacted with calcium and magnesium to produce calcium carbonate and magnesium carbonate.

One of the key factors in that system is the source of calcium and magnesium. For example, the use of industrial solid waste such as slag, fly ashes, or waste concrete from the steel industry has been proposed, but crushing is required to utilize the calcium and magnesium contained in the waste. ), activation or digestion, a series of pretreatment processes are required, and the amount of metal ions that can be utilized is limited, making it difficult to increase the efficiency of the overall process.

In addition, conventional carbon dioxide capture methods have the disadvantages of low carbonate conversion efficiency within reaction conditions due to low mass transfer efficiency, difficulty in continuous processing, large system volume, and high maintenance costs.

One object of the present invention is to provide a carbon dioxide mineralization system with high efficiency using a seawater desalination process brine and membrane contactor.

However, the problem to be solved by the present invention is not limited to the above-mentioned problem, and may be expanded in various ways without departing from the spirit and scope of the present invention.

A carbon dioxide mineralization system according to exemplary embodiments of the present invention for achieving the above-described object of the present invention includes a reaction unit including a hollow fiber separation membrane; a gas providing unit providing flue gas containing carbon dioxide within the hollow fiber separation membrane; a liquid provider providing brine generated in a seawater desalination process to a space surrounding the outer surface of the hollow fiber membrane; and a carbonate separation unit that separates carbonate from the brine that has passed through the reaction unit.

According to one embodiment, the carbon dioxide mineralization system further includes a liquid storage unit that stores the brine before being delivered to the reaction unit, and the liquid storage unit adjusts the pH of the brine to 10 to 14.

According to one embodiment, the carbon dioxide mineralization system further includes a solution discharge unit through which brine separated from carbonate is delivered to the carbonate separation unit, and the solution discharge unit discharges a preset ion concentration of the brine separated from carbonate. If it is within the allowable range, the brine is discharged, and if it is outside the allowable discharge range, the brine is sent to the liquid storage unit.

According to one embodiment, the carbon dioxide mineralization system further includes a gas outlet through which the flue gas passing through the reaction unit is delivered, and the gas discharge unit has a carbon dioxide concentration of the flue gas passing through the reaction unit within a preset emission tolerance range. If , the flue gas is discharged, and if it is outside the allowable discharge range, the flue gas is sent to the gas providing unit.

According to one embodiment, the hollow fiber membrane has hydrophobicity so as not to allow water to penetrate into the pores, and the water contact angle of the membrane surface is 80° to 120°.

According to one embodiment, the hollow fiber separator includes polyvinylidene fluoride.

According to one embodiment, the hollow fiber separator is surface treated with fluorosilane or chlorosilane.

According to one embodiment, the hollow fiber separator includes a high-density layer and a low-density layer having a density smaller than the high-density layer.

According to one embodiment, the high-density layer is adjacent to the cavity of the hollow fiber separator, and the low-density layer is adjacent to the outer surface of the hollow fiber separator.

According to one embodiment, the low-density layer includes first pores having a finger shape extending in the diameter direction of the hollow fiber separator, and the high-density layer includes second pores smaller than the first pores.

According to one embodiment, the low-density layer further includes third pores that are smaller than the first pores and larger than the second pores.

According to one embodiment, the first pores have an average width of 10 μm or more and a length of 50 μm or more, the second pores have an average size of 0.01 μm to 0.9 μm, and the third pores have an average size of 0.01 μm to 0.9 μm. It has a size of 1㎛ to 10㎛.

According to one embodiment, the thickness ratio of the high-density layer to the total thickness of the hollow fiber separator is 0.2 to 0.3.

According to one embodiment, the porosity of the hollow fiber separator is 80% or more.

According to the exemplary embodiments of the present invention described above, brine from the seawater desalination process can be recycled as an inflow solution to provide a source of calcium and magnesium without complex pretreatment, and brine with a high salt concentration can be used to prevent marine life from being affected. can be prevented.

In addition, the carbon dioxide mineralization system can have high efficiency because carbon dioxide capture, separation, and conversion can be performed within a single system.

In addition, the carbon dioxide mineralization system can increase carbon dioxide capture efficiency by using a hollow fiber membrane contactor, and the operating conditions can be easily controlled to selectively produce carbonate and carbonate structure.

Figure 1 is a block diagram schematically showing a carbon dioxide mineralization system according to an embodiment of the present invention.
Figure 2 is a schematic diagram showing the membrane contactor module and reaction process of the carbon dioxide mineralization system according to an embodiment of the present invention.
Figure 3 is a cross-sectional view showing a hollow fiber separation membrane of a membrane contactor module of a carbon dioxide mineralization system according to an embodiment of the present invention.
Figure 4 is an enlarged cross-sectional view of area A of Figure 3.
Figure 5 is a field emission scanning electron microscope (FESEM) photograph showing a cross section of the hollow fiber separator obtained according to Preparation Example 1.
Figure 6 is a surface photograph (a), an enlarged surface photograph (b), and a water contact angle measurement photograph (c) of the hollow fiber separator obtained according to Preparation Example 1.

Hereinafter, a carbon dioxide mineralization system according to an embodiment of the present invention will be described in detail with reference to the attached drawings. Since the present invention can be subject to various changes and can take various forms, specific embodiments will be illustrated and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all changes, equivalents, and substitutes included in the spirit and technical scope of the present invention. In the attached drawings, the dimensions of the structures are enlarged from the actual size for clarity of the present invention.

The terms used in this application are only used to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, or a combination thereof described in the specification, but are not intended to indicate the presence of one or more other features or numbers. It should be understood that this does not exclude in advance the possibility of the existence or addition of steps, operations, components, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

Figure 1 is a block diagram schematically showing a carbon dioxide mineralization system according to an embodiment of the present invention.

Referring to FIG. 1, the carbon dioxide mineralization system includes a liquid storage unit that stores brine (salt water) generated in the seawater desalination process, a flue gas supply unit that provides flue gas, and a system that receives the brine and the flue gas. It includes a reaction section in which carbonate is generated by a reaction between brine and the flue gas.

The carbon dioxide mineralization system can be applied to a seawater desalination system. For example, the seawater desalination system may include a desalination line for desalinating seawater by reverse osmosis and a desalination plant for generating energy required for the desalination process, and the carbon dioxide mineralization system may be connected to the desalination line and the desalination plant. It can be connected to provide brine and flue gas.

The liquid storage unit may be connected to a seawater desalination process line to receive brine. For example, the brine may refer to a by-product from a seawater desalination process. The seawater desalination process converts saltwater (seawater) into freshwater using a reverse osmosis method, and the seawater separated from freshwater becomes concentrated water (brine) with a higher concentration than the original.

The liquid storage unit receives and stores the brine from the seawater desalination process line. Additionally, the liquid storage unit can adjust the pH of the brine.

In order to be used in carbon dioxide mineralization, the brine preferably has alkaline properties. For example, the pH of the brine may be 7 to 14, and for a rapid mineralization reaction, it may be 10 to 14. The specific appropriate pH may vary depending on the type of carbonate to be produced.

For example, the liquid storage unit may further include a pH adjustment unit 12. The pH control unit 12 may include a pH sensor 12 for detecting the pH of the brine, and if necessary depending on the pH of the brine (when the pH of the brine is lower than the set pH), an alkali such as NaOH may be added. can be input into the brine.

The carbon dioxide mineralization system may include a liquid injection unit that transfers the brine from the liquid storage unit to the reaction unit. The liquid injection unit may include a known injection means such as a pump. Additionally, the liquid injection unit may further include an opening/closing valve for controlling the delivery path. Additionally, the liquid injection unit may be part of the structure of the liquid storage unit.

For example, the flow rate of brine injected from the solution providing unit into the reaction unit may be 0.01 L/min to 3 L/min. If the flow rate of the brine is excessively low, carbonate production efficiency may be reduced due to a decrease in the ion concentration difference, etc., and if it is excessively high, the hollow fiber membrane of the reaction unit may be damaged or deformed.

For example, the flow rate of flue gas injected from the gas providing unit into the reaction unit may be 0.1 to 100 sccm. If the flow rate of the flue gas is excessively high, carbon dioxide diffusion from the inside of the hollow fiber membrane to the surface may be reduced, thereby reducing carbonate production efficiency, and if it is excessively low, the overall gas processing capacity may be reduced.

Additionally, the liquid storage unit or the liquid provision unit may include temperature control means (heating unit and/or cooling unit) for controlling the temperature of the brine.

According to one embodiment, the carbon dioxide mineralization system may include a gas providing unit that provides the flue gas to the reaction unit. The gas providing unit may be connected to a desalination plant that generates flue gas. According to one embodiment, the gas providing unit may include a temperature sensor 18 and a temperature control means. For example, the temperature sensor 18 may sense the temperature of the flue gas and cool the flue gas if it is not within an appropriate temperature range, for example, if the temperature is excessively high. Through this, it is possible to prevent high temperature gas from damaging or deforming the membrane contactor of the reaction unit.

Carbonate is generated as the brine reacts with the flue gas in the reaction section. The carbonate may have various compositions and structures depending on the composition of the brine, the composition of the flue gas, reaction conditions, etc.

The brine may contain a high concentration of cations and anions, including metal ions. For example, the brine is Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Fe ²⁺ , Mn ²⁺ , Sr ²⁺ , Cl ^- , Br ^- , SO ₄ ^2- , NO ₃ ^- , PO ₄ It may contain at least one ion selected from the group consisting of ^3- and HCO ₃ ^- .

For example, the flue gas contains at least carbon dioxide and may further contain nitrogen gas, oxygen gas, carbon monoxide, etc.

For example, carbonates formed through the reaction unit include aragonite, calcite, gaspeite, magnesite, natrite, and cedar of the anhydrous carbonate group. It may include one or more selected from the group consisting of siderite and vaterite.

For example, the carbonate formed through the reaction unit is ankerite, barytocalcite, dolomite, and huntite of the anhydrous carbonate with compound formulas group. It may include one or more selected from the group consisting of.

For example, the carbonate formed through the reaction unit may include anhydrous carbonate with hydroxyl or halogen.

For example, the carbonate produced through the reaction unit is hydromagnesite, ikaite, lansfordite, monohydrocalcite, and nateron of the hydrated carbonate group. It may include one or more selected from the group consisting of (natron) and zellerite.

For example, the brine may contain sodium, magnesium, and calcium at high concentrations, and accordingly, the carbonate may include sodium carbonate, magnesium carbonate, calcium carbonate, etc.

Carbonate produced through the reaction unit may be dissolved or dispersed and included in the reaction solution (brine).

The brine containing the carbonate moves to the carbonate separation unit. The carbonate separation unit separates the carbonate from the brine. For example, the carbonate separation unit may cool the brine to precipitate/precipitate the carbonate. For example, the carbonate separation unit may cool the brine to 10°C or lower or 5°C or lower. Precipitated and precipitated carbonates can be filtered in the carbonate separation unit or external space and then dried. The finally obtained solid carbonate can be industrially recycled or disposed of in an appropriate manner.

However, the embodiments of the present invention are not limited thereto, and may be used without limitation in various known methods for removing carbonate from a solution containing carbonate.

The solution separated from carbonate in the carbonate separation unit may be discharged to the outside through the solution discharge unit. For example, the solution separated from the carbonate can be discharged into the sea. The solution separated from the carbonate has a lower ion concentration than the brine initially supplied from the seawater desalination device. Therefore, when discharged as wastewater, adverse effects on marine ecosystems, etc. can be minimized.

According to one embodiment, the solution discharge unit may provide a solution (post-processed solution) separated from the carbonate to the liquid storage unit for recycling. The treated solution provided to the liquid storage unit may be pH adjusted in the liquid storage unit and then provided back to the reaction unit.

Additionally, the solution discharge unit may determine whether to discharge or recycle the post-processed solution depending on the ion concentration of the post-processed solution. For example, the solution discharge unit may include a concentration/salinity sensor 14 capable of measuring ion concentration and/or salinity, through which the ion concentration (metal ion concentration) and salinity of the solution after treatment are measured. Thus, if it is within a preset reference range (permissible discharge range), the treated solution can be discharged, and if it is outside the allowable discharge range, the treated solution can be returned to the liquid storage unit.

According to one embodiment, the flue gas that has passed through the reaction unit may be discharged to the outside through a gas discharge unit. The flue gas reacts with brine in the reaction section to reduce the carbon dioxide content. Therefore, the amount of carbon dioxide in waste gas discharged to the outside can be reduced.

According to one embodiment, the gas discharge unit may include a gas concentration sensor 16. The gas concentration sensor 16 measures the carbon dioxide content of the flue gas (post-processed gas) that has passed through the reaction unit, and if it is within a preset emission tolerance range, discharges the processed gas, and if it is outside the emission tolerance range. , the gas after the treatment can be returned to the gas providing unit.

The exhaust operation of the gas exhaust portion may be determined by various conditions. For example, if the pressure of the gas supply section is excessively high (e.g., when the amount of flue gas provided from a desalination plant increases), the gas discharge section may cause the carbon dioxide content to be outside the allowable emission range, Gas may be discharged after the above treatment.

According to one embodiment, the carbon dioxide mineralization system may include a control unit for controlling/adjusting the operation of each unit. For example, the control unit is connected to the pH sensor 12, the concentration/salinity sensor 14, the gas concentration sensor 16, and the temperature sensor 18, and according to the measurement results of the sensors, The operation of at least one of the liquid storage unit, the liquid provision unit, the solution discharge unit, the gas discharge unit, and the gas provision unit can be controlled/adjusted.

The reaction unit may include a container that accommodates the membrane contactor. For example, the brine may be provided in a reaction space outside the membrane contactor, and the flue gas may be provided inside the membrane contactor. The configuration of the reaction unit and the membrane contactor will be described in detail later.

For example, the reaction temperature (temperature of brine) of the reaction unit may be 0°C to 90°C. For example, the reaction pressure of the reaction unit may be 1 to 10 atmospheres. For example, the reaction in the reaction unit may proceed at room temperature/normal pressure. The preferred reaction temperature and reaction pressure of the reaction unit may vary depending on process efficiency, flue gas, etc.

Figure 2 is a schematic diagram showing the membrane contactor module and reaction process of the carbon dioxide mineralization system according to an embodiment of the present invention. Figure 3 is a cross-sectional view showing a hollow fiber separation membrane of a membrane contactor module of a carbon dioxide mineralization system according to an embodiment of the present invention. Figure 4 is an enlarged cross-sectional view of area A of Figure 3.

2 to 4, the reaction unit includes a membrane contactor 100 and a container 200 for accommodating brine. Additionally, the reaction unit may include a gas inlet 212, a gas outlet 214, a liquid inlet 222, and a liquid outlet 224.

The gas inlet 212 and the gas outlet 214 may be connected to the membrane contactor 100. For example, the gas inlet 212 and the gas outlet 214 may be connected to both ends of the membrane contactor 100, respectively.

The membrane contactor 100 includes a hollow fiber separator 102 having a hollow (HA). The flue gas may be provided into the hollow (HA) of the hollow fiber separator 102 through the gas inlet 212. The flue gases follow the hollow (HA). It can move in one direction within the hollow fiber separation membrane 102 and can go out of the reaction section through the gas outlet 214.

At least a portion of the receiving space of the container 200 in which the membrane contactor 100 is not disposed may be filled with brine. For example, brine may be provided to entirely surround the membrane contactor 100 within the container 200. The brine may flow into the container 200 through the liquid inlet 222 and out of the container 200 through the liquid outlet 224.

The brine can move within the container 200. For example, within the container 200, the brine may move in a direction opposite to the direction of movement of the flue gas. However, embodiments of the present invention are not limited to this, and the brine may move in the same direction as the movement direction of the flue gas within the container 200. The direction of movement of the brine may be determined depending on the positions of the liquid inlet 222 and the liquid outlet 224.

According to one embodiment, the liquid inlet 222 may be placed at the bottom of the container 200, and the liquid outlet 224 may be placed at the top of the container 200. However, embodiments of the present invention are not limited thereto. For example, the liquid inlet 222 may be placed at the top of the container 200, and the liquid outlet 224 may be placed at the bottom of the container 200. Additionally, at least one of the liquid inlet 222 and the liquid outlet 224 may be disposed on the side surface of the container 200. The positions of the liquid inlet 222 and the liquid outlet 224 may be determined in consideration of the moving direction of brine, concentration distribution of brine, contact efficiency with flue gas, etc.

Carbon dioxide in the flue gas flowing into the hollow interior of the hollow fiber membrane 102 penetrates the hollow fiber membrane 102 and moves to the surface (outer surface) of the hollow fiber membrane 102, and the hollow fiber membrane ( 102) On the surface of brine, carbonate may be formed (mineralized) by reacting with cations in the brine.

For efficient mineralization, the hollow fiber membrane 102 has high carbon dioxide permeance, high hydrophobicity (surface hydrophobicity), and selectivity (permeation selectivity) of carbon dioxide with respect to other gas components (e.g., nitrogen). It is desirable that the selectivity (or diffusion selectivity) is high. If the hydrophobicity of the hollow fiber membrane 102 is low, brine penetrates into the hollow fiber membrane 102, thereby reducing the durability of the hollow fiber membrane 102 and reducing the liquid-gas reaction area, leading to a mineralization reaction. The efficiency may drop drastically.

For example, the carbon dioxide permeability within the membrane contactor of the hollow fiber separation membrane 102 may be 10 GPU or more, preferably 50 GPU or more, and more preferably 100 GPU or more. GPU (Gas Permeation Unit) is a physical quantity that represents the flow rate per unit area, unit time, and unit pressure, and is 1 GPU = 10 ^-6 cm3/cm2ㅇsㅇcmHg.

For example, the selectivity of the hollow fiber membrane 102 for carbon dioxide relative to nitrogen may be 1 or more, preferably 10 or more, and more preferably 20 or more.

For example, the water contact angle (according to a water contact angle analyzer) of the hollow fiber separator 102 may be 80° to 120°, preferably 90° to 120°, and more preferably 100° to 100°. It may be 120˚.

The hollow fiber separator 102 may contain a polymer. For example, the hollow fiber separator 102 is made of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylonitrile (PAN), and polyamide (polyamide). PA), polyimide (PI), polysulfone (PS), polyethersulfone (PES), polyetherimide (PEI), polyethylene (PE), polyetheretherketone , PEEK), sulfonated polyetheretherketone (SPEEK), polybenzimidazole (PBI), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), Poly(trimethylsilyl propyne), PTMSP, poly(trimethylgermylpropyne), PTMGP, polymethylpentene (PMP), polydimethylsiloxane (PDMS), polycarbonate (polycarbonate, PC), poly(ethylene oxide), PEO, polyphenylene oxide (PPO), polymer of intrinsic microporosity (PIM), chitosan, polyacrylic acid ( poly(acrylic acid), PAA), poly(sodium styrenesulfonate), PSS, polyvinyl sulfate (PVS), polypropylene (PP), polypyrrole, PPy), a group consisting of polyphosphazene (PPz), polyurethane (PU), cellulose acetate, nitrocellulose, cellulose esters and ethyl cellulose It may include at least one selected from.

According to one embodiment, the hollow fiber separator 102 may be formed of polyvinylidene fluoride. A hollow fiber membrane made of polyvinylidene fluoride has excellent mechanical properties, high hydrophobicity, and high carbon dioxide permeability.

For example, a hollow fiber-type separator can be manufactured by spinning a solution in which a polymer such as polyvinylidene fluoride is dissolved, and to form pores, a material such as LiCl can be added as an additive.

According to one embodiment, post-treatment may be performed to further increase the surface hydrophobicity of the hollow fiber separator 102. For example, the surface of the hollow fiber separator 102 may be post-treated with a fluorosilane compound. For example, the fluorosilane compound is 1H,1H,2H,2H-perfluorooctyltriethoxysilane (1H,1H,2H,2H-Perfluorooctyltriethoxysilane, OTES), 1H,1H,2H,2H-Purple It may include 1H, 1H, 2H, 2H-Perfluorodecyltriethoxysilane (DTES), etc. In another embodiment, the surface of the hollow fiber membrane 102 may be post-treated with a chlorosilane compound such as dimethyldichlorosilane (DDS), methyltrichlorosilane (MTS), etc.

Before proceeding with the post-treatment, the surface of the hollow fiber separator 102 may be treated with alkali so that the surface of the hollow fiber separator 102 can react with the hydrophobicity increasing material.

Referring to FIGS. 3 and 4 , the hollow fiber separator 102 may include a high-density layer 102a and a low-density layer 102b. The low-density layer 102b has a lower density than the high-density layer 102a. For example, the low-density layer 102b may have a larger porosity than the high-density layer 102a, and the low-density layer 102b may include larger pores than the high-density layer 102a.

According to one embodiment, the low-density layer 102b may include finger-shaped first pores P1 extending in the radial direction (DR) of the hollow fiber separator 102. The high-density layer 102a may include second pores (P2) that are smaller than the first pores (P1). Additionally, the low-density layer 102b may further include third pores P3 that are smaller than the first pores P1 and larger than the second pores P3.

For example, the finger-shaped first pore P1 may have, on average, a width of 10 μm or more and a length (radial length) of 50 μm or more. For example, the first pore P1 may have, on average, a width of 10 μm to 50 μm and a length of 50 μm to 200 μm.

For example, the second pore P2 may have a size (diameter) of 0.01 ㎛ to 0.9 ㎛ on average, and preferably 0.05 ㎛ to 0.3 ㎛.

For example, the third pore may have an average size of 1㎛ to 10㎛.

According to one embodiment, the porosity of the hollow fiber separator 102 may be 50% or more, and preferably 80% or more. For example, the porosity may be 80% to 95%, and more preferably, 84% to 89%. If the porosity is excessively large, the mechanical properties of the hollow fiber separation membrane 102 may be reduced, and if the porosity is excessively small, carbon dioxide permeability may be reduced.

For example, the thickness ratio of the high-density layer 102a to the total thickness of the hollow fiber separator 102 may be 0.1 to 0.5, and in one embodiment, 0.2 to 0.3.

If the thickness of the high-density layer 102a is too small, the mechanical properties and carbon dioxide selectivity of the hollow fiber separator 102 may be reduced. Additionally, if the thickness of the low-density layer 102b is too small, the total reaction area may decrease, thereby reducing mineralization efficiency. For example, the total thickness of the hollow fiber separator 102 may be 0.1 mm to 0.5 mm, and the thickness of the high-density layer 102a may be 0.02 mm to 0.1 mm.

According to one embodiment, the hollow fiber separator 102 may include a skin layer having a density greater than the low-density layer 102b outside the low-density layer 102b. The skin layer may include pores that are smaller than the first pores P1, for example, having an average size of 0.01 μm to 0.9 μm.

However, embodiments of the present invention are not limited to this, and the configuration of the hollow fiber separator 102 may change depending on process conditions such as pressure, temperature, etc.

According to one embodiment, the high-density layer 102a may be adjacent to the hollow HO, and the low-density layer 102b may be adjacent to the outer surface and spaced apart from the hollow HO. Accordingly, the low-density layer 102b may have a shape surrounding the high-density layer 102a. However, embodiments of the present invention are not limited to this, and the low-density layer 102b may be adjacent to the hollow HO, and the high-density layer 102a may be configured to be spaced apart from the hollow HO and adjacent to the outer surface. .

Additionally, the high-density layer 102a and the low-density layer 102b may be formed of the same material or may be formed of different materials.

According to embodiments of the present invention, carbon dioxide can be captured through the reaction of by-products generated in a seawater desalination system. In addition, the carbon dioxide capture effect can be increased by increasing the liquid-gas reaction area through a hollow fiber membrane capable of selectively permeating carbon dioxide, and the type and composition of carbonate to be obtained can be adjusted because the reaction conditions are easy to control. do.

In addition, since the hollow fiber membrane has high hydrophobicity, it prevents brine from penetrating into the membrane, thereby maintaining carbon dioxide permeability even under long-term operating conditions.

Hereinafter, the operation and effects of the carbon dioxide mineralization system according to exemplary embodiments will be described in more detail through specific experimental examples. The above experimental examples are provided merely as examples, and the scope of the present invention is not limited to the content provided in the above experimental examples.

Preparation Example 1 Preparation of hollow fiber separator

According to Table 1 below, polyvinylidene fluoride (PVDF) pellets (Kynar 740) were dissolved in N-Methyl-2-Pyrrolidone (NMP), and Lithium Chloride (LiCl) and Pluronic F- were added to form pores. A PVDF solution was prepared by adding 127 as an additive (using a 60°C oil bath and a mechanical stirrer) and then spun according to Table 2 to prepare a PVDF hollow fiber membrane.

Figure 5 is a field emission scanning electron microscope (FESEM) photograph showing a cross section of the hollow fiber separator obtained according to Preparation Example 1. Figure 6 is a surface photograph (a), an enlarged surface photograph (b), and a water contact angle measurement photograph (c) of the hollow fiber separator obtained according to Preparation Example 1.

Referring to FIG. 5, it can be seen that the hollow fiber separator obtained according to Preparation Example 1 has a low-density layer with finger-shaped voids and a high-density layer with micropores.

Table 3 below shows the characteristics of the hollow fiber separator obtained according to Preparation Example 1.

Production example 2

The hollow fiber membrane of Preparation Example 1 was soaked in an alkaline solution (0.01M NaOH) for 30 minutes, washed in ultrapure water for 3 minutes, and dried in an oven at 70°C for 3 hours. Next, the alkali-treated hollow fiber membrane was soaked in DDS/MTS (volume ratio 2:3) diluted with toluene (toluene 80 vol%) for 30 minutes, and then mixed with toluene, ethanol, ethanol/water (volume ratio 1:1), and water. Washing was carried out in order. Next, the hollow fiber membrane was dried in an oven at 60°C for 3 hours.

Production example 3

Treatment to increase the hydrophobicity of the hollow fiber membrane was performed in the same manner as Preparation Example 2, except that OTES was used instead of DDS/MTS.

Production example 4

Treatment to increase the hydrophobicity of the hollow fiber membrane was performed in the same manner as Preparation Example 2, except that DTES was used instead of DDS/MTS.

Referring to Table 4 below, it can be seen that the hydrophobicity was further increased through reaction with the hydrophobicity increasing treatment material.

Example 1

membrane contactor module

A membrane contactor module (reaction section) with a reaction section inner diameter of 1/4 inch, an effective length of 12 cm, and an effective area of 13.5 cm2 was prepared using six PVDF hollow fiber separators obtained in Preparation Example 1 and a Swagelok tube fitting.

brine model

To replace brine in the seawater desalination process, a brine model with a composition similar to actual brine was manufactured. Specifically, Calcium Chloride (CaCl ₂ ), Magnesium Chloride (MgCl ₂ ), and Sodium Chloride (NaCl) were added to 1L or more of ultrapure water, and the concentrations of Ca2+, Mg2+, and Na+ were 947 mg/L, 2,709 mg/L, and 24,466 mg, respectively. A brine model with /L was prepared, and the pH was adjusted to 10 to 11 by adding sodium hydroxide.

The reaction unit is connected to a reservoir (storing brine before injection), a reservoir (storing brine after reaction), a peristaltic pump, and a gas chromatograph (YL6500 GC), and the brine model and nitrogen/ Carbon dioxide mixed gas (volume ratio 80:20) was supplied into the reaction unit. The reaction in the reaction unit was carried out at room temperature and pressure, and the effluent solution containing the produced carbonate was recovered through a reservoir, and the carbon dioxide removal rate through the reaction unit was measured using gas chromatography. Carbonate recovered from the storage was filtered through a vacuum filtration device, dried in a vacuum oven, and then analyzed through XRD pattern analysis. Table 5 below shows the process conditions, carbon dioxide removal rate, and carbonate component of the reaction.

Although the present invention has been described with reference to exemplary embodiments as described above, those skilled in the art will understand that the present invention can be varied without departing from the spirit and scope of the present invention as set forth in the following patent claims. You will understand that it can be modified and changed.

The carbon dioxide mineralization system according to exemplary embodiments of the present invention can be used in plants, factories, ships, etc. that use a seawater desalination system.

Claims (14)

A reaction unit including a hollow fiber separation membrane;
a gas providing unit providing flue gas containing carbon dioxide within the hollow fiber separation membrane;
a liquid provider providing brine generated in a seawater desalination process to a space surrounding the outer surface of the hollow fiber membrane; and
A carbon dioxide mineralization system comprising a carbonate separation unit that separates carbonate from the brine that has passed through the reaction unit. According to paragraph 1,
A carbon dioxide mineralization system further comprising a liquid storage unit that stores the brine before being delivered to the reaction unit, wherein the liquid storage unit adjusts the pH of the brine to 10 to 14. The method of claim 2, further comprising a solution discharge unit through which the brine separated from the carbonate is delivered, wherein the solution discharge unit discharges the brine when the ion concentration of the brine separated from the carbonate is within a preset allowable discharge range. A carbon dioxide mineralization system characterized in that it discharges and, if it is outside the allowable discharge range, sends the brine to the liquid storage unit. The method of claim 1, further comprising a gas discharge unit through which the flue gas passing through the reaction unit is delivered, wherein the gas discharge unit discharges the flue gas when the carbon dioxide concentration of the flue gas passing through the reaction unit is within a preset emission allowance range. A carbon dioxide mineralization system characterized in that the flue gas is discharged and, if the emission is outside the allowable range, sent to the gas provider. The carbon dioxide mineralization system according to claim 1, wherein the hollow fiber membrane has hydrophobicity so as not to allow water to penetrate into the pores, and the water contact angle is 80° to 120°. The carbon dioxide mineralization system of claim 5, wherein the hollow fiber membrane includes polyvinylidene fluoride. The carbon dioxide mineralization system of claim 6, wherein the hollow fiber membrane is surface treated with fluorosilane or chlorosilane. The carbon dioxide mineralization system of claim 1, wherein the hollow fiber membrane includes a high-density layer and a low-density layer having a density less than the high-density layer. The carbon dioxide mineralization system of claim 8, wherein the high-density layer is adjacent to the cavity of the hollow fiber membrane, and the low-density layer is adjacent to the outer surface of the hollow fiber membrane. The method of claim 8, wherein the low-density layer includes first pores having a finger shape extending in the diameter direction of the hollow fiber separator, and the high-density layer includes second pores smaller than the first pores. carbon dioxide mineralization system. 9. The carbon dioxide mineralization system of claim 8, wherein the low-density layer further includes third pores that are smaller than the first pores and larger than the second pores. The method of claim 11, wherein the first pores have an average width of 10 μm or more and a length of 50 μm or more, the second pores have an average size of 0.01 μm to 0.9 μm, and the third pores have an average size of 0.01 μm to 0.9 μm. A carbon dioxide mineralization system characterized by having a size of 1㎛ to 10㎛. The carbon dioxide mineralization system of claim 8, wherein the thickness ratio of the high-density layer to the total thickness of the hollow fiber separation membrane is 0.2 to 0.3. The carbon dioxide mineralization system according to claim 1, wherein the hollow fiber membrane has a porosity of 80% or more.

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