Continuous process and system for the production of sodium bicarbonate crystals

Abstract

The present invention relates to a continuous process for the production of sodium bicarbonate crystals from a gaseous stream of carbon dioxide, comprising a step of absorbing carbon dioxide from the gaseous stream into an aqueous solution containing a sodium carbonate salt to produce an aqueous solution of sodium bicarbonate, followed by a step of crystallizing the sodium bicarbonate salt obtained in the first step. The present invention also relates to a system for the production of sodium bicarbonate crystals from a gaseous stream of carbon dioxide, comprising a control unit 10, an absorption unit 20 and a crystallization unit 30.

Description

[Technical Field]

[0001] Field of Invention This invention relates to a continuous process for producing sodium bicarbonate crystals from a gaseous flow of carbon dioxide.

[0002] The present invention also relates to a system for the continuous production of sodium bicarbonate crystals from a gaseous flow of carbon dioxide. [Background technology]

[0003] Background of the Invention Global warming is a serious problem. The alarming rise in atmospheric CO2 levels is prompting research groups and industries to seek solutions to halt the steady increase in global temperatures and their dramatic consequences. Government authorities and international academic societies are encouraging the development of sustainable processes that utilize renewable sources, with the goal of reducing greenhouse gas emissions. To reduce emissions from the industrial sector, the capture and reuse of carbon dioxide as a raw material in the production of marketable products can be not only economically viable but also a profitable business.

[0004] Of the many possible chemical products that can be produced from CO2, sodium bicarbonate (NaHCO3) is particularly interesting because it is an inorganic salt that can be used in numerous applications in the chemical, food, textile, and pharmaceutical industries, and, depending on the production process, has the potential to contribute to carbon mitigation by softening the greenhouse effect.

[0005] Regarding the production of sodium bicarbonate from CO2 reuse, four main steps are required: CO2 purification, dissolution of sodium carbonate, carbonation reaction, and separation of sodium bicarbonate.

[0006] Sodium bicarbonate is a white powdered salt characterized by being a water-soluble chemical. Industrial-scale production of sodium bicarbonate first began in 1846. Later, in 1860, Belgian industrial scientist Ernest Solvay developed an improved industrial method for the production of sodium carbonate and sodium bicarbonate.

[0007] Due to the strong demand for sodium bicarbonate, research has been conducted with the aim of proposing methods for producing sodium bicarbonate that demonstrate higher conversion rates, adaptability of raw materials, and economic viability, thereby contributing to CO2 mitigation.

[0008] To date, two main routes have been developed: the Solvay process and the carbonation of soda ash from trona. Of the main raw materials used in the sodium bicarbonate production process, sodium chloride has been shown to be the most economically feasible, while sodium carbonate has been shown to be the most environmentally viable alternative.

[0009] Traditionally, the global production of sodium bicarbonate has been almost entirely carried out by the Solvay process, which uses CO2, NH3, and NaCl as the main reactants. However, the presence of ammonia, which is considered an environmentally and health-hazardous compound, remains one of the main drawbacks of the Solvay process, and companies in the field are shifting to the trona-to-soda ash carbonate process for large-scale sodium bicarbonate production.

[0010] The natural mineral trona (Na2CO3-NaHCO3-2H2O) is extracted from nature. Trona is stable up to 57°C, and between 57°C and 160°C it produces intermediate compounds such as wegsheiderite (Na2CO3-3NaHCO3) and sodium monohydrate (Na2CO3-H2O), and above 160°C it decomposes into sodium carbonate.

[0011] The inventors are aware, for example, of U.S. Patent No. 9,382,125, which describes a process for the co-production of crystalline sodium bicarbonate, in which CO2 is prepared as an intermediate and at least a portion thereof is used as a feed material for the sodium bicarbonate production step from sodium carbonate.

[0012] The inventors are also aware of patent application WO2013 / 106294, which describes a carbonation step for the production of sodium bicarbonate from trona. U.S. Patent No. 7,507,388 describes a step for the production of bicarbonate from trona, comprising the steps of purification, evaporation-decarboxylation, crystallization, centrifugation, and drying. U.S. Patent Application Publication 2020 / 0002183 describes an integrated step for the production of sodium bicarbonate from captured CO2 by a dry carbonation step from trona as a raw material and by converting trona to sodium carbonate. Part of the sodium carbonate is recycled as an adsorbent in the CO2 capture step, and the remainder is used together with part of the captured CO2 for the production of sodium bicarbonate.

[0013] However, a high level of thermal energy is required. The use of trona as a raw material, which is only available in a few parts of the world, can increase economic costs. The complete conversion of trona to sodium carbonate is required, followed by another carbonation step to produce sodium bicarbonate, a process that therefore involves a high level of energy consumption.

[0014] Thus, there is a need for a process that enables the production of high-purity sodium bicarbonate in an environmentally friendly and economically viable manner, while avoiding high energy consumption. [Overview of the project] [Problems that the invention aims to solve]

[0015] The object of the present invention is thus to provide a continuous process based on CO2 capture and reuse using membrane technology. First, the CO2-containing gas from industry is contacted with a basic solution that absorbs the CO2 present in the gas stream. Then, the resulting CO2-containing solution is sent to a membrane distillation-crystallization step where bicarbonate crystals are formed.

[0016] Advantageously, all steps are carried out at room temperature or low temperature (<50 °C), and sodium bicarbonate crystals are obtained with high purity and low energy consumption.

Means for Solving the Problems

[0017] Overview The present invention thus provides 1) An absorption step of carbon dioxide gas from a gas stream into an aqueous solution containing a sodium carbonate salt, comprising 1a) contacting the gas stream with a first surface of a first porous membrane contactor and contacting the aqueous solution of sodium carbonate with a second opposite surface of the same first porous membrane contactor, wherein the carbon dioxide gas diffuses through the pores of the membrane into the aqueous solution of sodium carbonate where it dissolves; 1b) reacting the dissolved carbon dioxide with the sodium carbonate salt in the aqueous solution to produce an aqueous solution of sodium bicarbonate, and being carried out in the presence of at least one mass transfer promoter selected from amino acids or enzymes, wherein the at least one mass transfer promoter is suspended in the aqueous solution of sodium carbonate or immobilized on the first porous membrane contactor, the absorption step; and then 2) A crystallization step of a sodium bicarbonate salt, comprising 2a) circulating an aqueous solution containing sodium bicarbonate on one side of a second porous membrane contactor; ​2b) By applying a driving force by circulating the extraction fluid on the opposite side of the second porous membrane contactor, the water in the aqueous solution evaporates and diffuses through the pores of the second porous membrane contactor toward the extraction fluid on the opposite side of the second porous membrane contactor, where the water recondenses, leading to the gradual concentration of the aqueous solution of sodium bicarbonate; 2c) A concentrated aqueous solution of sodium bicarbonate is sent to a crystallization tank located at the outlet of the second porous membrane contactor, where crystal growth occurs; 2d) Recover the sodium bicarbonate crystals. Includes, The first porous membrane contactor and the second porous membrane contactor described above are continuous. Crystallization step, This relates to a continuous process for producing sodium bicarbonate crystals, including the process described above.

[0018] According to one embodiment, at least one mass transfer promoter is an amino acid selected from L-arginine, 6-aminohexionine, L-valine, L-methionine, and L-serine.

[0019] According to another embodiment, at least one mass transfer enhancer is carbonic anhydrase.

[0020] According to one embodiment, the concentration of the mass transfer accelerator is 0.1 mg / L to 1 mg / L, preferably 0.1 mg / L to 0.5 mg / L.

[0021] According to one embodiment, the continuous process further includes the step of pre-filtering the mass transfer accelerator suspended in the solvent through a filtration membrane.

[0022] According to one embodiment, the gas flow is fuel gas from fossil fuel combustion, fuel gas from biofuel combustion, gas from natural resources, or a combination thereof.

[0023] According to one embodiment, the concentration of carbon dioxide gas in the gas flow is 5% to 40% by volume, preferably 5% to 20% by volume.

[0024] According to one embodiment, the concentration of sodium carbonate in the aqueous solution containing sodium carbonate is 0.1 mol / L to 2.0 mol / L, preferably 0.1 mol / L to 1.0 mol / L.

[0025] According to one embodiment, the Reynolds number of the gas flow is about 2 to about 15, preferably about 2 to about 10, and more preferably about 5 to about 10.

[0026] According to one embodiment, the Reynolds number of the aqueous solution containing sodium carbonate is about 2 to about 30, preferably about 2 to about 25, and more preferably about 10 to about 25.

[0027] According to one embodiment, the extraction fluid is selected from a liquid, a mixture of liquids, a concentrated aqueous solution of one or more salts, a gas, a mixture of gases, or a vacuum.

[0028] The present invention further, - A control unit configured to control the flow rate of the gas and / or liquid, and the temperature of the gas and / or liquid; - An absorption unit comprising a first porous membrane contactor configured to allow contact between a gas flow containing carbon dioxide gas and a solvent which is an aqueous solution of sodium carbonate, and a gear pump, The gas flow and the solvent are separated by the first porous membrane contactor, the first porous membrane contactor contains means for diffusing the carbon dioxide gas of the gas flow toward the solvent, where the carbon dioxide dissolves and reacts with sodium carbonate to produce sodium bicarbonate, the means being a porous absorption unit; - A crystallization unit comprising: a second porous membrane contactor configured to allow contact between an aqueous solution containing sodium bicarbonate to be crystallized, entering from an absorption unit, and the extraction fluid; a permeate tank containing the extraction fluid; and a crystallization tank in which crystallization occurs, A second membrane contactor is fluid-connected to the crystallization tank and the permeation tank. A crystallization unit in which aqueous solution water containing sodium bicarbonate to be crystallized enters from an absorption unit and circulates on one side of a second porous membrane contactor toward a crystallization tank, and an extracting fluid entering from a permeate tank circulates on the opposite side of the second porous membrane contactor, the second porous membrane contactor contains means for selective transport of aqueous solution water toward the opposite side, and the means are pores, A system for generating sodium bicarbonate crystals from a gaseous flow of carbon dioxide, including, This relates to a system in which the above-mentioned absorption unit and crystallization unit are in fluid communication.

[0029] In embodiments, the system of the present invention further includes a pre-filtration unit that is in fluid communication with the absorption unit and / or crystallization unit.

[0030] definition In this invention, the following terms have the following meanings:

[0031] The term "approximately" preceding a number means ±10% of the value of that number.

[0032] The term "continuous process" refers to a production method that can be carried out without interruption, i.e., the fluid being processed moves continuously, undergoes chemical reactions, and / or is subjected to mechanical and / or heat treatment.

[0033] The term "carbonic anhydrase (CA)" can be expressed as a maximum of 10 6 This refers to a metalloenzyme capable of catalyzing the conversion of CO2 to bicarbonate at an extremely high turnover rate, reaching speeds of 1 / second. It is found in humans, animals, plants, and microorganisms. Carbonic anhydrase may be selected from α-CA, β-CA, γ-CA, δ-CA, or ζ-CA.

[0034] The term "driving force" refers to the force that enables the movement of substances through the pores of the membrane contactor. According to the present invention, the driving force is selected from a temperature gradient, a concentration gradient, a partial pressure gradient, or a mixture thereof. The driving force is generated by circulating the extraction fluid on one side of the membrane contactor to induce a difference in concentration or partial pressure across both sides of the membrane. According to the present invention, the extraction fluid is selected from a liquid, a mixture of liquids, a concentrated aqueous solution of one or more salts, a gas, a gas mixture, or a vacuum.

[0035] The "Reynolds number" refers to a dimensionless number that predicts whether the flow is laminar (Re < 2500) or turbulent (Re < 5000).

[0036] The "membrane permeation flux J of gas" refers to the mass transfer flux of CO2 contained in the gas flow across the first porous membrane contactor. According to one embodiment, the membrane permeation flux J is given by Equation (1): (1) J = (G in × C in - G out × C out ) / Am (where C in and C out are the concentrations of CO2 in the gas at the inlet and outlet of the first porous membrane contactor, G in and G out are the volumetric flow rates of the gas at the inlet and outlet, and Am is the membrane area) and increases or decreases as a function thereof.

[0037] The "driving force ΔCm for carbon dioxide" is given by Equation (2) (2) ΔCm = (C in - C out ) / ln(C in / C out ) (where C in and C out are the CO2 concentrations in ppm in the gas at the inlet and outlet of the first porous membrane contactor) and increases or decreases as a function thereof.

[0038] The "water membrane permeation flux J'" refers to the mass transfer flux of aqueous water across the first porous membrane contactor. J' is determined by measuring the weight of the permeate tank over time. The flux is then calculated using equation (3).

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[0039] [Figure 1] This is a flowchart showing the steps of a continuous process according to one embodiment of the present invention. [Figure 2] This is a flowchart showing the steps of a continuous process according to another embodiment of the present invention. [Figure 3] This is a flowchart showing the steps of a continuous process according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0040] Detailed description Process The present invention relates to a series of steps for generating salt crystals, comprising the steps of bringing a gas stream containing at least one gas into contact with a solvent that absorbs at least a portion of the gas, and then sending the resulting solution to a membrane distillation-crystallization step in which salt crystals are generated.

[0041] According to one embodiment, the present invention involves the following steps: 1) A step of absorbing at least a portion of at least one gas contained in the gas flow into the solvent in order to produce an aqueous solution of the salt to be crystallized, 2) Crystallization step of the salt contained in the aqueous solution of the salt to be crystallized obtained in step 1), This relates to a continuous process for the formation of salt crystals, including the process described above.

[0042] According to one embodiment, the present invention relates to a continuous process for producing sodium bicarbonate crystals, comprising the steps of contacting a CO2-absorbing basic solution with a CO2-containing gas, and then sending the resulting CO2-containing solution to a membrane distillation-crystallization process in which bicarbonate crystals are produced.

[0043] In a particular embodiment, the present invention: 1) A step of absorbing at least a portion of carbon dioxide from a gas flow into an aqueous solution containing a sodium carbonate salt in order to produce an aqueous solution of sodium bicarbonate, and then 2) Crystallization step of the sodium bicarbonate salt contained in the aqueous solution of sodium bicarbonate obtained in the first step, This relates to a continuous process for producing sodium bicarbonate crystals, including the process described above.

[0044] Absorption step According to one embodiment, the first step is carried out by bringing a gas flow into contact with a first surface of a first porous membrane contactor, and bringing a solvent into contact with a second opposite surface of the first porous membrane contactor.

[0045] Advantageously, the physical separation between the solvent and the gas flow, which can be provided by the first porous membrane contactor, eliminates the forming and channeling problems faced in conventional solvent absorption where the gas and liquid are in direct contact.

[0046] According to one embodiment, the gas contained in the gas flow is an acidic gas selected from carbon dioxide, sulfur dioxide, sulfur trioxide, hydrogen sulfide, carbon oxysulfide, carbon disulfide, mercaptan, nitrogen oxide, nitrogen dioxide, fluoride, hydrochloric acid, or a mixture thereof.

[0047] According to another embodiment, the gas contained in the gas flow is a basic gas selected from ammonia.

[0048] According to a preferred embodiment, the gas contained in the gas flow is carbon dioxide gas.

[0049] According to one embodiment, the gas flow is fuel gas from fossil fuel combustion, fuel gas from biofuel combustion, gas from natural resources, or a combination thereof.

[0050] The concentration of the gas contained in the gas flow may vary over a wide range from 0 to 100% by volume, excluding 0% by volume. The above concentrations may be 0 to 10% by volume, 10 to 20% by volume, 20 to 30% by volume, 30 to 40% by volume, 40 to 50% by volume, 50 to 60% by volume, 60 to 70% by volume, 70 to 80% by volume, 80 to 90% by volume, or 90 to 100% by volume, excluding 0%.

[0051] According to one embodiment, the concentration of the gas contained in the gas flow is 5% to 40% by volume. According to one embodiment, the concentration of the gas contained in the gas flow is 5% to 20% by volume. According to one embodiment, the concentration of the gas contained in the gas flow is 10% to 20% by volume.

[0052] According to a special embodiment, the concentration of carbon dioxide gas in the gas flow is 5% to 40% by volume. According to a special embodiment, the concentration of carbon dioxide gas in the gas flow is 5% to 20% by volume. According to a special embodiment, the concentration of carbon dioxide gas in the gas flow is 10% to 20% by volume.

[0053] According to one embodiment, the solvent is an aqueous solution of one or more salts selected from alkaline salts, ammonium salts, alkanolamine salts, alkaline earth salts, or mixtures thereof.

[0054] According to one embodiment, the solvent is an aqueous solution of one or more alkaline salts selected from sodium carbonate, calcium carbonate, sodium acetate, potassium cyanide, sodium sulfide, sodium bicarbonate, calcium hydroxide, magnesium hydroxide, or sodium hydroxide. In a preferred embodiment, the solvent is an aqueous solution of sodium carbonate.

[0055] According to one embodiment, the gas contained in the gas flow diffuses through the pores of the first porous membrane contactor, driven by the concentration gradient, toward the solvent where at least a portion of it dissolves and gives the gas to the solution.

[0056] According to a particular embodiment, carbon dioxide gas in a gas flow diffuses through the pores of a first porous membrane contactor, driven by its concentration gradient, toward the solvent where at least a portion of it dissolves, giving carbon dioxide to the solution.

[0057] According to a special embodiment in which the solvent is an aqueous solution of one or more salts, the dissolved gas then reacts with the one or more salts to produce one or more different salts referred to in the present invention as "crystallized salts."

[0058] According to one embodiment, the one or more salts to be crystallized are selected from sodium bicarbonate, sodium carbonate, calcium carbonate, calcium bicarbonate, magnesium carbonate, sodium sulfate, or ammonium sulfate.

[0059] According to a preferred embodiment, the salt that is crystallized is sodium bicarbonate.

[0060] According to a special embodiment in which the solvent is an aqueous solution of sodium carbonate, the dissolved carbon dioxide then reacts with the aqueous solution of sodium carbonate to form reaction (1.1):

number

[0061] According to one embodiment, mass transfer between the gas and solvent in a gas flow occurs in three steps: a) Diffusion from the bulk gas phase to the gas-film interface; b) Diffusion through the pores of the membrane; c) Migration from the liquid-membrane interface to the bulk liquid phase through the liquid boundary layer, which is a layer of liquid immediately adjacent to the first porous membrane contact. It happens there.

[0062] According to one embodiment, the mass transfer between the gas and solvent contained in the gas flow is expressed by the overall mass transfer coefficient (K OV Characterized by:

[0063] According to one embodiment, the overall mass transfer coefficient is given by the following equation (4): (4)K OV =J / ΔCm (wherein J is the transmembrane flux of the gas contained in the gas flow through the first porous membrane contactor, and ΔCm is the driving force of gas absorption) increases or decreases as a function of ΔCm.

[0064] Several parameters, including the Reynolds number (Re) of both the gaseous and liquid phases, the driving force between the gas flow and the solvent, the flow velocities of the solvent and gas within the first porous membrane contactor, the composition of the gas phase, the concentration of salts in the solvent, and the temperature, can influence the mass transfer of gases in the gas flow toward the solvent.

[0065] According to one embodiment, the Reynolds number of the gas flow, preferably flowing inside the shell, is given by the following equation (5): (5) Re = ρvdh / μ It increases or decreases as a function of .

[0066] In an embodiment in which the first porous membrane contactor is in the form of a hollow fiber, the Reynolds number of the solvent, preferably flowing on the lumen side, is given by the following equation (6): (6) Re = ρvdi / μ (In the formula, ρ is kg / m 3 The fluid density is at , v is the fluid velocity in m / s, μ is the dynamic viscosity in Pas, di is the inner diameter of the fiber, and dh is the hydraulic diameter (dh is 4A / P, where A = cross-sectional area and P is the wet edge of the cross-section) and increases or decreases as a function of .

[0067] In one embodiment, the Reynolds number of the gas flow is about 2 to about 15. In one embodiment, the Reynolds number of the gas flow is about 2 to about 10. In one embodiment, the Reynolds number of the gas flow is about 5 to about 10. In one embodiment, the Reynolds number of the gas flow is about 5, about 6, about 7, about 8, about 9, and about 10. In a preferred embodiment, the Reynolds number of the gas flow is about 9.

[0068] In one embodiment, the Reynolds number of the solvent is about 2 to about 30. In one embodiment, the Reynolds number of the solvent is about 2 to about 25. In one embodiment, the Reynolds number of the solvent is about 10 to about 25. In one embodiment, the Reynolds number of the solvent is about 10, about 11, about 12, about 13, about 14, about 15, about 16, about 17, about 18, about 19, about 20, about 21, about 22, about 23, about 24, about 25. In a preferred embodiment, the Reynolds number of the solvent is about 20.

[0069] In one embodiment, the concentration of the salt, preferably sodium carbonate, in the solvent is 0.1 mol / L to 2.0 mol / L. In one embodiment, the concentration of the salt in the solvent is 0.1 mol / L to 1.0 mol / L. In one embodiment, the concentrations of the salt in the solvent are 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1.0 mol / L. In a preferred embodiment, the concentration of the salt in the solvent is 0.5 mol / L.

[0070] In one embodiment, the solvent flows in parallel with the gas flow. In a preferred embodiment, the solvent flows in the opposite direction to the gas flow.

[0071] Advantageously, by increasing the gas flow and / or solvent flow velocity, the reduction of the boundary layer reduces resistance to mass transfer and increases the gas flux, particularly the flux of carbon dioxide gas, which leads to an increase in the mass transfer coefficient across the membrane. Nevertheless, there exists an optimal Reynolds number that can be calculated by those skilled in the art.

[0072] According to one embodiment, the absorption step 1) is carried out at a temperature of 15°C to 40°C. In one embodiment, the absorption step is carried out at a temperature of 20°C to 35°C. In one embodiment, the absorption step is carried out at temperatures of 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, and 35°C. In one embodiment, the absorption step is carried out at a temperature of 35°C.

[0073] According to one embodiment, the overall mass transfer coefficient of the absorption step 1) is 0.001 m / min to 0.1 m / min. In one embodiment, the overall mass transfer coefficient of the absorption step is 0.001 m / min to 0.01 m / min. In one embodiment, the overall mass transfer coefficient of the absorption step is 0.001 m / min to 0.0085 m / min. In one embodiment, the overall mass transfer coefficient of the absorption step is 0.001 m / min to 0.0025 m / min.

[0074] According to one embodiment, absorption step 1) is carried out in the presence of at least one mass transfer accelerator.

[0075] Advantageously, mass transfer enhancers allow for an increase in the overall mass transfer coefficient.

[0076] According to one embodiment, at least one mass transfer accelerator is selected from enzymes that catalyze the gas conversion of amino acids or salts to be crystallized.

[0077] According to one embodiment, at least one mass transfer accelerator is an amino acid selected from L-arginine, 6-aminohexanoic acid, L-valine, L-methionine, and L-serine. According to a preferred embodiment, at least one mass transfer accelerator is L-arginine.

[0078] In another preferred embodiment, at least one mass transfer accelerator is an enzyme selected from any enzymes that use carbon dioxide as a substrate, and in a preferred embodiment, is a carbonic anhydrase that catalyzes the conversion of carbon dioxide to sodium carbonate.

[0079] In one embodiment, the enzyme is selected from the following Table 1: [Table 1]

[0080] Advantageously, the use of carbonic anhydrase can be up to 10 6 By catalyzing the conversion of carbon dioxide to bicarbonate at an extremely high turnover rate, which can reach up to 1 / second, it enables an increase in carbon dioxide gas absorption rate.

[0081] In one embodiment, more than one substrate is used, and in an embodiment in which two substrates are used, the second substrate may be a liquid phase.

[0082] According to one embodiment, at least one mass transfer accelerator is suspended in a solvent, preferably an aqueous solution of one or more salts, particularly an aqueous solution of sodium carbonate.

[0083] According to one embodiment, at least one mass transfer accelerator is suspended in a solvent at a concentration of 0.1 mg / L to 1 mg / L. According to another embodiment, at least one mass transfer accelerator is suspended in a solvent at a concentration of 0.1 mg / L to 0.5 mg / L.

[0084] According to another embodiment, if at least one mass transfer promoter is an enzyme, the enzyme may be immobilized on the first porous membrane contactor.

[0085] Advantageously, enzyme immobilization improves its recovery and reuse.

[0086] Crystallization step According to one embodiment, the crystalline salt contained in the aqueous solution of the crystalline salt obtained in the first step is subsequently crystallized by film crystallization in crystallization step 2). According to a preferred embodiment, the sodium bicarbonate salt contained in the aqueous solution of the crystalline salt obtained in the first step is subsequently crystallized by film crystallization.

[0087] According to one embodiment, the second step is carried out by circulating an aqueous solution containing the crystallizable salt obtained in the first step, preferably an aqueous solution of sodium bicarbonate, on one side of the second porous membrane contactor, and by applying a driving force by circulating an extraction fluid on the opposite side of the second porous membrane contactor.

[0088] According to one embodiment, a vapor / liquid interface is generated at the pore openings of the second porous membrane contactor, and water in the aqueous solution of the salt to be crystallized evaporates and diffuses through the pores of the second porous membrane contactor toward the extraction fluid on the opposite side of the second porous membrane contactor, where it recondenses, resulting in the gradual concentration of the aqueous solution containing the salt to be crystallized.

[0089] According to one embodiment, a concentrated aqueous solution containing the salt to be crystallized, preferably sodium bicarbonate, is sent to a crystallization tank located at the outlet of a second porous membrane contactor where crystal growth occurs (step 2c), and the salt crystals, preferably sodium bicarbonate crystals, are recovered, for example, by vacuum filtration (step 2d).

[0090] According to one embodiment, the driving force is selected from a temperature gradient, a concentration gradient, a partial pressure gradient, or any combination thereof.

[0091] According to one embodiment, the extraction fluid is selected from a liquid, a mixture of liquids, a concentrated aqueous solution of one or more salts, a gas, a mixture of gases, or a vacuum.

[0092] According to a particular embodiment, the extraction fluid is a condensing fluid such as pure water. In this embodiment, the driving force is the temperature difference between the solvent containing the salt to be crystallized and the condensing fluid.

[0093] According to a particular embodiment, the extracted fluid is a permeable solution. In this embodiment, the driving force is the concentration difference on both sides of the second porous membrane contactor.

[0094] According to a particular embodiment, the extracted fluid is air. In this embodiment, the driving force is a partial pressure gradient across a second porous membrane contactor.

[0095] According to a particular embodiment, the extraction fluid is a sweep gas. In this embodiment, the driving force is a partial pressure gradient across a second porous membrane contactor.

[0096] According to a particular embodiment, the extracted fluid is a vacuum. In this embodiment, the driving force is a partial pressure gradient across a second porous membrane contactor.

[0097] Advantageously, both sides of the second porous membrane contactor are independent, and therefore the operating conditions can be modified independently on both sides of the second membrane contactor to control the crystallization dynamics, leading to the formation of specific crystal morphologies and structures that are not easily achieved in conventional crystallization.

[0098] According to one embodiment, the mass transfer between the solvent and the extraction fluid is governed by an overall mass transfer coefficient (K OV Characterized by:

[0099] According to one embodiment, the overall mass transfer coefficient for the crystallization step is given by equation (7) (7)K OV =J' / Δp * It increases or decreases as a function of (wherein J' is the transmembrane flux of water in the aqueous solution across the membrane, and Δp* is the vapor pressure difference between the aqueous solution of sodium bicarbonate and the extracting fluid).

[0100] Several parameters, such as the Reynolds number of both the aqueous solution and the extracting fluid, the flow velocity of the aqueous solution, the flow velocity of the extracting fluid within the membrane contactor, the concentration of the aqueous solution, or the temperature of both the aqueous solution and the extracting fluid, can affect the mass transfer of water from the aqueous solution toward the extracting fluid.

[0101] In one embodiment, the Reynolds number of the aqueous solution of the crystallized salt, preferably sodium bicarbonate, obtained in step 1) is 2 to 20. In one embodiment, the Reynolds number of the aqueous solution of the crystallized salt is about 5 to about 20. In one embodiment, the Reynolds number of the aqueous solution of the crystallized salt is about 5 to about 15. In one embodiment, the Reynolds number of the aqueous solution of the crystallized salt is about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, about 15. In a preferred embodiment, the Reynolds number of the aqueous solution of the crystallized salt is about 7.

[0102] In one embodiment, the Reynolds number of the extracted fluid is 2 to 20. In one embodiment, the Reynolds number of the extracted fluid is about 2 to about 10. In one embodiment, the Reynolds number of the extracted fluid is about 10 to about 20. In one embodiment, the Reynolds number of the extracted fluid is about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 11, about 12, about 13, about 14, and about 15. In a preferred embodiment, the Reynolds number of the extracted fluid is about 3. In another preferred embodiment, the Reynolds number of the extracted fluid is about 15.

[0103] According to one embodiment, the aqueous solution of the salt to be crystallized, preferably an aqueous solution of sodium bicarbonate, is at a temperature in the range of 15°C to 50°C. In one embodiment, the aqueous solution of the salt to be crystallized is at a temperature in the range of 15°C to 40°C. In one embodiment, the aqueous solution of the salt to be crystallized is at a temperature in the range of 15°C to 30°C. In one embodiment, the aqueous solution of the salt to be crystallized is at a temperature of 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C. In one embodiment, the aqueous solution of the salt to be crystallized is at a temperature of 25°C.

[0104] In one embodiment, the extraction fluid is at a temperature in the range of 2°C to 25°C. In another embodiment, the extraction fluid is at a temperature in the range of 2°C to 15°C.

[0105] According to one embodiment, the overall mass transfer coefficient in the crystallization step is 2 × 10 -11 m / Pa / sec~10×10 -11 The value is m / Pa / second. In one embodiment, the overall mass transfer coefficient for the crystallization step is 2 × 10⁻⁶ -11 m / Pa / sec~7×10 -11 The value is m / Pa / second. In one embodiment, the overall mass transfer coefficient of the crystallization step is 4 × 10⁻⁶. -11 m / Pa / sec~10×10 -11 The value is m / Pa / second. In one embodiment, the overall mass transfer coefficient of the crystallization step is 4 × 10⁻⁶. -11 m / Pa / sec~7×10 -11 It is m / Pa / second.

[0106] In one embodiment, at least 10% of the sodium bicarbonate present in the aqueous solution of the crystallized salt obtained in step 1) is crystallized in step 2). In one embodiment, at least 20% of the crystallized salt is crystallized. In one embodiment, at least 30% of the crystallized salt is crystallized. In one embodiment, at least 40% of the crystallized salt is crystallized. In one embodiment, at least 50% of the crystallized salt is crystallized. In one embodiment, at least 60% of the crystallized salt is crystallized. In one embodiment, at least 70% of the crystallized salt is crystallized. In one embodiment, at least 80% of the crystallized salt is crystallized. In one embodiment, at least 90% of the crystallized salt is crystallized. In one embodiment, 100% of the crystallized salt is crystallized.

[0107] According to one embodiment, salt crystals, preferably sodium bicarbonate crystals, can be obtained with a purity of more than 99%.

[0108] Advantageously, the crystallization dynamics, as well as the final form and structure of the crystalline material, can be easily controlled by acting on process parameters such as concentration, flow rate, temperature, and film type.

[0109] According to one embodiment, the first and second film contactors are continuous and provide a continuous process.

[0110] Advantageously, the continuous process of the present invention can be operated at room temperature or low temperature (<50°C), reducing energy consumption compared to conventional processes for salt crystals, particularly sodium bicarbonate crystals.

[0111] Furthermore, salt crystals, particularly sodium bicarbonate crystals, can be used directly, bringing economic value to the process of the present invention.

[0112] Membrane contactor According to one embodiment, the first and / or second film contactors are independently hydrophobic films comprising a first surface and a second surface opposite to the first surface.

[0113] According to one embodiment, the first and / or second membrane contactors are independently formed as flat sheets. According to one embodiment, the first and / or second membrane contactors are independently formed as helical membrane contactors. According to a preferred embodiment, the first and / or second membrane contactors are independently formed as hollow fibers.

[0114] Advantageously, hollow fiber membrane contactors have a higher specific surface area, increasing mass transfer from one side to the other.

[0115] According to one embodiment, the first and / or second membrane contactors are independently formed as a plurality of hollow fibers.

[0116] According to one embodiment, the first surface of the first and / or second membrane contactor is the inner surface of the hollow fiber, and the second opposite surface is the outer surface of the hollow fiber.

[0117] According to one embodiment, the first surface of the first and / or second membrane contactor is the outer surface of the hollow fiber, and the second opposite surface is the inner surface of the hollow fiber.

[0118] According to one embodiment, the plurality of hollow fibers are filled in a tube-and-shell arrangement.

[0119] In one embodiment, the gas flow passes through the lumen side of the first membrane contactor, and the solvent flows through the shell side. In another embodiment, the gas flow passes through the shell side of the first membrane contactor, and the solvent flows through the lumen side of the first membrane contactor.

[0120] According to one embodiment, the solvent containing the crystallized salt flows through the lumen side of the second membrane contactor, and the extracted fluid flows through the shell side of the second membrane contactor. According to another embodiment, the solvent containing the crystallized salt flows through the shell side of the second membrane contactor, and the extracted fluid flows through the lumen side of the second membrane contactor.

[0121] In one embodiment, the first and / or second films have a thickness of 10 μm to 100 μm, preferably 40 μm to 50 μm.

[0122] According to one embodiment, the first and / or second membrane contactors include a microporous membrane. According to one embodiment, the first and / or second membrane contactors have a membrane having a plurality of micropores having an average diameter of 0.03 μm to 0.1 μm, preferably micropores having a surface area of ​​0.03 × 0.1 μm.

[0123] According to one embodiment, the first and / or second membrane contactors are independently made from polymers selected from polyenes, polyalkenes, polysulfones (PSUs), polyethersulfones (PESs), perfluoropolymers, polyetherimides (PEIs), polymethylpentenes (PMPs), and polydimethylsiloxanes (PDMSs).

[0124] According to a preferred embodiment, the first and / or second membrane contactors are independently made from polymers selected from polypropylene (PP), polyethylene (PE), polymethylpentene (PMP), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyetheretherketone (PEEK).

[0125] Pre-filtration step According to one embodiment, if at least one mass transfer accelerator is suspended in a solvent, the continuous process of the present invention further includes the step of pre-filtering the mass transfer accelerator suspended in the solvent through a filtration membrane.

[0126] According to one embodiment, once recovered, the filtered mass transfer accelerator may be resuspended in the solvent used in absorption step 1) for reuse.

[0127] According to one embodiment, the step of pre-filtering the mass transfer accelerator is performed after the absorption step. This embodiment is advantageous when the mass transfer accelerator is an enzyme.

[0128] According to another embodiment, the step of pre-filtering the mass transfer accelerator is carried out after the crystallization step. This embodiment is particularly advantageous when the mass transfer accelerator is an amino acid, because amino acids can assist in the crystallization of salts, especially sodium bicarbonate.

[0129] The embodiments previously presented herein for the processes of the present invention are applicable to the entire description, and in particular to all embodiments described herein below for the system of the present invention, with appropriate modifications.

[0130] system The present invention also relates to a system 1 for generating salt crystals from a gas contained in a gas flow, comprising a control unit 10, an absorption unit 20, and a crystallization unit 30.

[0131] According to one embodiment, the control unit 10 is configured to control the flow velocities of different fluids, and optionally their temperatures.

[0132] According to one embodiment, the absorption unit 20 is configured to enable the absorption of gases contained in a gas flow into a solvent which is an aqueous solution of one or more salts.

[0133] According to one embodiment, the absorption unit 20 includes a first porous membrane contactor configured to allow contact between a gas flow and a solvent, and a gear pump.

[0134] According to one embodiment, the gas contained in the gas flow diffuses toward the solvent through the pores of the first porous membrane contactor, where it dissolves and reacts with at least one salt to produce at least one salt that crystallizes.

[0135] According to one embodiment, the crystallization unit 30 is configured to enable the crystallization of at least one type of salt to be crystallized that enters from the absorption unit 20.

[0136] According to one embodiment, the crystallization unit 30 includes a second porous membrane contactor configured to allow contact between an aqueous solution containing at least one salt to be crystallized and an extraction fluid, a permeate tank containing the extraction fluid, and a crystallization tank in which the crystallization of at least one salt to be crystallized takes place.

[0137] According to one embodiment, the water in an aqueous solution containing at least one salt to be crystallized evaporates and diffuses through the pores of the second porous membrane contactor toward the extraction fluid circulating on the opposite side of the second porous membrane contactor, where it recondenses and results in the gradual concentration of the aqueous solution containing the salt to be crystallized.

[0138] In such embodiments where a crystallization tank is present, most crystallization, particularly crystal growth, occurs in the crystallization tank. Nevertheless, some nucleation and some crystal growth may also occur in the crystallization unit 30 before the concentrated aqueous solution containing the salt to be crystallized enters the crystallization tank.

[0139] According to one embodiment, the absorption unit 20 and the crystallization unit 30 are in fluid communication, so that the aqueous solution containing at least one salt to be crystallized, entering from the absorption unit 20, flows continuously from the absorption unit 20 to the crystallization unit 30.

[0140] According to one embodiment, the system further includes a pre-filtration unit 40 in which the pre-filtration step 40 of the mass transfer accelerator described earlier may be carried out. The pre-filtration step 40 is preferably in fluid communication with an absorption unit 20 and / or a crystallization unit 30.

[0141] Advantageously, the system of the present invention enables continuous processing of gaseous flows, such as fuel gases from fossil fuel combustion, fuel gases from biofuel combustion, gases from natural resources, or combinations thereof, with low energy consumption, and allows for the capture of gases, particularly carbon dioxide, and their reuse in salt crystals, particularly sodium bicarbonate crystals.

[0142] Another advantage of the system of the present invention described below in this specification is its modularity and high adaptability. The number and arrangement of membrane contactors can be easily adapted as needed, thus reducing energy costs and enabling simple linear scale-up and modular design. Increased production volume can be easily achieved by adding membrane modules.

[0143] Figure 1 shows a special embodiment of the execution of the process of the present invention utilizing System 1, in which a gas flow 2 enters the first porous membrane contactor 3 of the absorption unit 20 through a first inlet opening 4 located on one side of the first porous membrane contactor. A solvent 5 containing at least one mass transfer accelerator enters the first porous membrane contactor 3 through a second inlet opening 6 located on the other side of the first porous membrane contactor and flows in the reverse direction of the gas flow. After the gas contained in the gas flow is absorbed by the solvent 5, the resulting depleted gas flow 7 is released from the first porous membrane contactor 3 through a first outlet opening 8 located on the opposite side of the first inlet opening 4. A solvent 9 containing the salt to be crystallized and at least one mass transfer accelerator exits the first porous membrane contactor 3 through a second outlet opening 11 located on the opposite side of the second inlet opening 6 and is then sent to the crystallization unit 30 using a gear pump 12.

[0144] As shown in Figure 1, the solvent 9 containing the crystallized salt and at least one mass transfer accelerator enters the second porous membrane contactor 13 through a first inlet opening 14 located on one side of the second membrane contactor. The extraction fluid 15 entering from the permeate tank 6 is sent to the second porous membrane contactor 13 using a gear pump (not shown) and enters the second porous membrane contactor 13 through a second inlet opening 17 located on the other side of the second porous membrane contactor, flowing in reverse against the CO2-containing solvent 9. The extraction fluid 15 exits the second porous membrane contactor 13 through a second outlet opening 18 located on the opposite side of the second inlet opening 17 and is returned to the permeate tank for reuse.

[0145] Referring further to Figure 1, after the solvent 9 containing the salt to be crystallized and at least one mass transfer accelerator evaporates towards the extraction fluid 15 inside the second porous membrane contactor 13, the resulting concentrated solvent 19 containing the salt to be crystallized and at least one mass transfer accelerator exits the second porous membrane contactor 13 through the first inlet opening 21 located opposite the first inlet opening 14 and is then sent to the crystallization tank 22 where crystallization takes place. After crystallization, the remaining concentrated solvent 19 containing the salt to be crystallized and at least one mass transfer accelerator is returned to the absorption unit 20 using a gear pump 23 without further processing for reuse, and the salt crystals 24 are recovered using vacuum filtration.

[0146] Figure 2 shows another special embodiment of the execution of the process of the present invention utilizing System 1, wherein System 1 further includes a pre-filtration unit 40 that is in fluid communication with an absorption unit and a crystallization unit.

[0147] In this embodiment shown in Figure 2, the solvent 9 containing the salt to be crystallized and at least one mass transfer accelerator exits the first porous membrane contactor through a second inlet opening 11 and is then sent to a pre-filtration unit 40, where at least one mass transfer accelerator 22 is separated from the solvent 9. After separation, the at least one mass transfer accelerator 22 is returned to the absorption unit 20 for reuse, and the solvent 9' containing the salt to be crystallized is sent to the crystallization unit 30.

[0148] After crystallization, the remaining concentrated solvent 19' containing the crystallized salt is returned to the crystallization unit 30 without further treatment for reuse, and the salt crystals 24 are recovered using vacuum filtration.

[0149] This embodiment is advantageous when the mass transfer accelerator is an enzyme.

[0150] Figure 3 shows another special embodiment of the process of the present invention utilizing System 1, in which the pre-filtration unit 40 is in fluid communication with the crystallization unit 30.

[0151] In this embodiment shown in Figure 3, a solvent 9 containing the salt to be crystallized and at least one mass transfer accelerator is sent to a crystallization unit 30. After crystallization, the remaining concentrated solvent 19 containing the salt to be crystallized and at least one mass transfer accelerator is sent to a filtration unit 40, where at least one mass transfer accelerator 22 is separated from the concentrated solvent 19. The at least one mass transfer accelerator 22 is returned to an absorption unit for reuse, and the concentrated solvent 19' containing the salt to be crystallized is returned to the crystallization unit 30 for reuse, and the salt crystals 24 are recovered using vacuum filtration. In some embodiments, Na2CO3 may be added to the concentrated solvent 19. The above addition may increase the recovery of the amino acid used as the mass transfer accelerator 22.

[0152] This embodiment is advantageous when the mass transfer accelerator is an amino acid, because the amino acid can assist in the crystallization of sodium bicarbonate.

[0153] According to one embodiment, system 1 further includes a heater configured to heat a gaseous and / or liquid flux.

[0154] According to one embodiment, system 1 further includes a cooling device configured to cool the extracted fluid.

[0155] According to one embodiment, when the extraction fluid is under vacuum, system 1 further includes a condenser configured to condense water evaporating through a second membrane contactor.

[0156] According to one embodiment, the solvent 5 can be recycled and reused at the end of the process.

[0157] According to one embodiment, the amount of solvent 5 can be adjusted during the process. In particular, further amounts of solvent can be added at any time as needed.

[0158] While various embodiments have been described and illustrated, the detailed descriptions should not be construed as limiting the embodiments to what is described herein. Various modifications can be made to the embodiments by those skilled in the art without departing from the true spirit and scope of the disclosure as defined in the claims.

[0159] Examples The present invention is further illustrated by the following embodiments.

[0160] Example 1: Production of sodium bicarbonate crystals using L-arginine or carbonic anhydrase as a mass transfer accelerator This example demonstrates the formation of sodium bicarbonate crystals from carbon dioxide in a gaseous flow using L-arginine or carbonic anhydrase as a mass transfer enhancer.

[0161] Materials and methods Chemicals The gas flow consists of 85% air by volume and 15% carbon dioxide by volume with a purity of 99.7% or higher by volume.

[0162] An aqueous solution of sodium carbonate was prepared by diluting sodium carbonate with deionized water.

[0163] Bovine carbonic anhydrase or L-arginine was used as a mass transfer enhancer.

[0164] material The first and second membrane contactors used to perform the experiment are 3M® Liqui-Cel® MM-1x5.5 series membrane contactors. The characteristics of the membranes are summarized in Table 2. [Table 2]

[0165] method On the gas side, preferably the shell side, the gas flow enters the first membrane contactor in parallel with the aqueous sodium carbonate solution.

[0166] On the liquid side, preferably the lumen side, an aqueous solution of sodium carbonate containing L-arginine or carbonic anhydrase flows through the first membrane contactor.

[0167] The CO2 concentration at the outlet is measured in parts per million at each second of the experiment using a CO2 analyzer.

[0168] Solvent samples are taken from a liquid valve at any time to analyze the chemical species (carbonates, bicarbonates, etc.) in the solution.

[0169] The aqueous sodium carbonate solution captures carbon dioxide from the gas flow and exits the first membrane contactor, heading towards the second membrane contactor.

[0170] The CO2-containing solution enters a second membrane contactor, where it is concentrated and circulated towards a crystallization tank where crystallization occurs. There, the concentrated solution is mixed by a mixer (Heidolph RZR 2051 control, Germany) and maintained at a constant temperature via a temperature controller (Julabo Corio CD-BC4, Germany).

[0171] Three different settings are used on the transparency side.

[0172] Setting 1: The permeate tank is filled with deionized water cooled to a certain temperature by a cooling device. The deionized water circulates through the permeate side of the membrane via a gear pump (Cole-Parmer 7511-70, USA) and returns to the permeate tank.

[0173] Setting II: The permeation side is maintained under vacuum by a vacuum pump (Vacuubrand MD4CNT, Germany), and the water evaporated through the membrane is condensed in a condenser (glass condenser and Julabo Corio CD-900F, Germany). A controller (Vacuu-select, Vacuubrand, Germany) monitors the vacuum level.

[0174] Setup III: The permeate tank is filled with an osmotic solution (i.e., a solution containing a high concentration of salt). The osmotic solution is circulated through the permeate side of the membrane via a gear pump (Cole-Parmer 7511-70, USA) and returned to the permeate tank.

[0175] The salt contained in the osmotic solution may include, for example, NaCl, or consist solely of NaCl. The NaCl concentration is preferably in the range of 200 to 300 mg / L, and in particular, it is about 300 mg / L.

[0176] In settings I, II, and III, the weight of the permeation tank is monitored by a balance (LP 4202 I, VWR, Italy), and the temperature is recorded by a temperature data logger (Testo 176 T2, Belgium) connected to a PT100 temperature probe (Fabritius, Belgium).

[0177] Once crystals appear in the crystallization tank, the process is stopped, and the solution is filtered using vacuum filtration (Whatman 1442 125 filter). The sodium bicarbonate crystals are then held in a desiccator to be gently dried before characterization.

[0178] The experimental conditions used in the experiment are summarized in Table 3. [Table 3]

[0179] The CA concentration ranged from 0.1 to 100 mg / L.

[0180] Characterization of crystals Crystal Form The morphology of the crystals can be examined using a scanning electron microscope (SEM).

[0181] Crystal size distribution The crystal size distribution is quantified using a wet granulation method (microparticle measuring instrument).

[0182] Crystal yield The crystal yield is quantified by weighing the crystals after filtering and drying the NaHCO3.

[0183] result The maximum mass transfer coefficient was calculated for the absorption step using L-arginine or carbonic anhydrase (CA) as a mass transfer enhancer, and for the crystallization step under three different settings. The results are reported in Table 4.

[0184] The purity of the bicarbonate crystals was determined for all experiments. [Table 4]

[0185] A purity exceeding 99% was obtained in the bicarbonate crystals under setting III. A purity of 95% was obtained in the bicarbonate crystals under setting II, and high purity was also obtained in the bicarbonate crystals under setting I.

[0186] conclusion The process according to the present invention uses L-arginine or carbonic anhydrase as a mass transfer accelerator to produce sodium bicarbonate crystals from a gaseous flow of carbon dioxide. The sodium bicarbonate crystals obtained by the process of the present invention exhibit a high purity exceeding 99%.

Claims

1. 1) A step of absorbing carbon dioxide gas from a gas flow into an aqueous solution containing a sodium carbonate salt, 1a) A step of bringing a first surface of a first porous membrane contactor into contact with the gas flow, and a second opposite surface of the same first porous membrane contactor into contact with the aqueous solution of sodium carbonate, wherein the gaseous carbon dioxide diffuses into the aqueous solution of sodium carbonate through the pores of the membrane and dissolves therein; 1b) A step of reacting the sodium carbonate salt in the aqueous solution with the dissolved carbon dioxide in order to produce an aqueous solution of sodium bicarbonate, Includes, The procedure is carried out in the presence of at least one mass transfer enhancer selected from amino acids or enzymes. The at least one mass transfer accelerator is suspended in the aqueous solution of sodium carbonate or fixed on the first porous membrane contactor. Absorption step; then 2) A crystallization step of sodium bicarbonate, 2a) The step of circulating the aqueous solution containing sodium bicarbonate on one side of the second porous membrane contactor; 2b) A step of applying a driving force by circulating the extracting fluid on the opposite side of the second porous membrane contactor such that the water in the aqueous solution evaporates and diffuses through the pores of the second porous membrane contactor toward the extracting fluid on the opposite side of the second porous membrane contactor, where it recondenses and results in the gradual concentration of the aqueous solution of sodium bicarbonate; 2c) The step of sending the concentrated aqueous solution of sodium bicarbonate to a crystallization tank located at the outlet of the second porous membrane contactor where crystal growth occurs; 2d) Step of recovering sodium bicarbonate crystals, Includes, The first porous membrane contactor and the second porous membrane contactor are continuous. Crystallization step, A continuous process for the production of sodium bicarbonate crystals, including the following:

2. The continuous process according to claim 1, wherein the at least one mass transfer promoter is an amino acid selected from L-arginine, 6-aminohexionine, L-valine, L-methionine, and L-serine.

3. The continuous process according to claim 1, wherein the at least one mass transfer promoter is carbonic anhydrase.

4. The continuous process according to any one of claims 1 to 3, wherein the concentration of the mass transfer accelerator is 0.1 mg / L to 1 mg / L.

5. The continuous process according to any one of claims 1 to 4, further comprising the step of pre-filtering the mass transfer accelerator suspended in the solvent through a filtration membrane.

6. The continuous process according to any one of claims 1 to 5, wherein the gas flow is fuel gas from fossil fuel combustion, fuel gas from biofuel combustion, gas from natural resources, or a combination thereof.

7. The continuous process according to any one of claims 1 to 6, wherein the concentration of carbon dioxide in the gas flow is 5% by volume to 40% by volume.

8. The continuous process according to any one of claims 1 to 7, wherein the concentration of the sodium carbonate in the aqueous solution containing the sodium carbonate is 0.1 mol / L to 2.0 mol / L.

9. The continuous process according to any one of claims 1 to 8, wherein the Reynolds number for the gas flow is about 2 to about 15.

10. The continuous process according to any one of claims 1 to 9, wherein the Reynolds number for the aqueous solution containing a sodium carbonate salt is about 2 to about 30.

11. The continuous process according to any one of claims 1 to 10, wherein the extraction fluid is selected from a liquid, a mixture of liquids, a concentrated aqueous solution of one or more salts, a gas, a mixture of gases, or a vacuum.

12. - A control unit (10) configured to control the flow rate of the gas and / or liquid and the temperature of the gas and / or liquid; - A first porous membrane contactor configured to allow contact between a gas flow (2) containing carbon dioxide gas and a solvent (5) which is an aqueous solution of sodium carbonate; and an absorption unit (20) including a gear pump, The gas flow (2) and the solvent (5) are separated by the first porous membrane contactor (3), and the first porous membrane contactor contains means for diffusing the carbon dioxide of the gas in the gas flow toward the solvent (5), where it is dissolved and reacts with the sodium carbonate to produce sodium bicarbonate, and the means is porous, and an absorption unit (20); - A crystallization unit (30) comprising: a second porous membrane contactor (13) configured to allow contact between the aqueous solution containing the crystallized sodium bicarbonate entering from the absorption unit (20) and the extraction fluid; a permeate tank (16) containing the extraction fluid (15); and a crystallization tank (22) where the crystallization occurs, The second porous membrane contactor (13) is in fluid communication with the crystallization tank (22) and the permeation tank (16). Crystallization unit (30), wherein the water in the aqueous solution containing the sodium bicarbonate to be crystallized, entering from the absorption unit (20), circulates on one side of the second porous membrane contactor (13) toward the crystallization tank (22), and the extract fluid (15) entering from the permeate tank circulates on the opposite side of the second porous membrane contactor (13), and the second porous membrane contactor contains means for selective transport of the water in the aqueous solution toward the opposite side, wherein the means are pores. A system (1) for generating sodium bicarbonate crystals from a gaseous flow of carbon dioxide, including, The absorption unit (20) and the crystallization unit (30) are in fluid communication with each other in a system (1).

13. The system according to claim 12, further comprising a pre-filtration unit (40) that is in fluid communication with the absorption unit (20) and / or the crystallization unit (30).

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