Method and apparatus for producing carbonates

Abstract

The present invention efficiently produces a carbonate salt from a carbon dioxide gas in an exhaust gas. This production method for a carbonate salt comprises: an atomizing step wherein an aqueous alkali solution is formed into a mist by an atomizer; a mixing step wherein the mist of the aqueous alkali solution obtained in the atomizing step is mixed with an exhaust gas so as to have a carbon dioxide gas in the exhaust gas absorbed in the mist and to form a carbonate salt by bonding positive ions of the mist and the carbon dioxide gas with each other, thereby having the mist contain the carbonate salt; and a separation step wherein the mist containing the carbonate salt obtained in the mixing step is separated from the exhaust gas.

Description

[Technical Field]

[0001] This invention relates to a method and apparatus for producing carbonates using carbon dioxide contained in exhaust gas as a raw material. [Background technology]

[0002] A method for producing calcium carbonate using exhaust gas as a raw material has been developed. (Patent Document 1) The method described in this publication involves absorbing carbon dioxide from exhaust gas of a combustion furnace or the like with a caustic soda solution using a gas-liquid contact method to produce a sodium carbonate solution. Meanwhile, quicklime is hydrated with an aqueous caustic soda solution as the water of hydration to produce lime milk, and this lime milk is reacted with the sodium carbonate solution to synthesize calcium carbonate. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-293537 [Overview of the project] [Problems that the invention aims to solve]

[0004] The above method is a gas-liquid contact method in which exhaust gas is introduced into a caustic soda solution, and the carbon dioxide in the exhaust gas reacts with the caustic soda in the caustic soda solution to produce sodium carbonate. However, it is difficult to efficiently react the carbon dioxide in the exhaust gas with the caustic soda to produce sodium carbonate.

[0005] This invention was developed with the aim of overcoming this drawback, and an important objective of this invention is to provide a method and apparatus for producing carbonates that can efficiently produce carbonates using carbon dioxide from exhaust gas as a raw material. [Means for solving the problem]

[0006] A method for producing a carbonate according to an aspect of the present invention includes an atomization step of atomizing an aqueous alkali solution into a mist by an atomizer, a mixing step of mixing the mist of the aqueous alkali solution obtained in the atomization step with an exhaust gas to absorb carbon dioxide gas in the exhaust gas into the mist, binding a cation of the mist with the carbon dioxide gas to form a carbonate, and making the mist in a state containing the carbonate, and a separation step of separating the mist containing the carbonate obtained in the mixing step from the exhaust gas. Furthermore, in the atomization process, the average particle size of the alkaline aqueous solution mist is kept below 50 μm.

[0007] A carbonate production apparatus according to an aspect of the present invention includes an atomizer that atomizes an aqueous alkali solution into a mist, a mixer that mixes the mist generated by the atomizer with an exhaust gas to bind a cation of the mist with carbon dioxide gas to form a carbonate, and a separator that separates the mist obtained by the mixer from the exhaust gas and recovers the mist containing the carbonate. The atomizer ensures that the average particle size of the alkaline aqueous solution mist is 50 μm or less.

Advantages of the Invention

[0008] The above production method and production apparatus have the feature that a carbonate can be efficiently produced from carbon dioxide gas in the exhaust gas.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic configuration diagram of a carbonate production apparatus according to Embodiment 1 of the present invention. [Figure 2] It is a schematic configuration diagram showing an example of an atomizer, which is an ultrasonic atomizer. [Figure 3] It is an enlarged cross-sectional view showing a connection structure of an ultrasonic vibrator. [Figure 4] [[ID=​​​​​​​​​​​​ [Figure 9] This is a schematic diagram showing a wet scrubber, another example of an air pollutant pretreatment device. [Figure 10] This is a schematic diagram of a carbonate production apparatus according to Embodiment 2 of the present invention. [Figure 11] This is another example of an atomizer, a schematic diagram showing an electrostatic atomizer. [Figure 12] Figure 11 is an enlarged cross-sectional view showing the spray unit of the electrostatic atomizer. [Modes for carrying out the invention]

[0010] The present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "up," "down," and other terms including these) will be used as needed. The use of these terms is for the purpose of facilitating the understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Also, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or components. Furthermore, the embodiments described below illustrate specific examples of the technical concept of the present invention and do not limit the present invention to those described below. Also, the dimensions, materials, shapes, relative arrangements, etc., of the components described below are intended to be illustrative, and not to limit the scope of the present invention unless otherwise specified. Moreover, the content described in one embodiment or example is applicable to other embodiments and examples. Additionally, the size and positional relationships of the members shown in the drawings may be exaggerated for clarity.

[0011] The method for producing a carbonate according to the first invention of the present invention includes: an atomization step in which an alkaline aqueous solution is turned into a mist using an atomizer; a mixing step in which the mist of the alkaline aqueous solution obtained in the atomization step is mixed with exhaust gas to absorb carbon dioxide from the exhaust gas into the mist, and the cations of the mist combine with carbon dioxide to form a carbonate, thereby making the mist a state containing carbonate; and a separation step in which the mist containing carbonate obtained in the mixing step is separated from the exhaust gas.

[0012] The method for producing a carbonate according to the second invention of the present invention involves an atomizing process in which an atomizer vibrates an alkaline aqueous solution ultrasonically to produce a mist.

[0013] The third invention of the present invention relates to a method for producing carbonate, in which, in the atomization step, an atomizer vibrates an alkaline aqueous solution ultrasonically and blows exhaust gas onto the surface of a liquid column that protrudes from the liquid surface, thereby mixing the mist with the exhaust gas.

[0014] The fourth invention of the present invention relates to a method for producing carbonate, in which, in the atomization step, an atomizer vibrates an alkaline aqueous solution ultrasonically, blowing a conveying gas onto the surface of a liquid column protruding from the liquid surface to form a mist mixture gas, and in the mixing step, the mist mixture gas is mixed with exhaust gas.

[0015] The fifth invention of the present invention relates to a method for producing carbonate, in which, in the atomization step, an atomizer electrostatically atomizes the spray water of an alkaline aqueous solution ejected from a nozzle to form a mist.

[0016] The sixth invention of the present invention relates to a method for producing carbonate, in which, in the atomization step, an atomizer blows exhaust gas onto the mist that has been electrostatically atomized by spraying from a nozzle, thereby mixing the mist and the exhaust gas.

[0017] The seventh invention of the present invention relates to a method for producing carbonate, in which, in the atomization step, an atomizer blows a conveying gas onto the mist that is sprayed from a nozzle and electrostatically atomized to form a mist mixture, and in the mixing step, the mist mixture is mixed with exhaust gas.

[0018] The method for producing carbonate according to the eighth invention of the present invention is to ensure that the average particle size of the mist of the alkaline aqueous solution is 50 μm or less in the atomization step. Furthermore, the method for producing carbonate according to the ninth invention of the present invention is to ensure that the average particle size of the mist of the alkaline aqueous solution is 30 μm or less in the atomization step.

[0019] The method for producing carbonate according to the tenth invention of the present invention involves making the average particle size of the alkaline aqueous solution mist 100 nm or more in the atomization step.

[0020] The method for producing carbonate according to the 11th invention of the present invention involves using a caustic soda solution in an alkaline aqueous solution in an atomization step, reacting carbon dioxide from exhaust gas with caustic soda in the mist in a mixing step to produce a mist containing sodium carbonate, and separating the mist containing sodium carbonate from the exhaust gas in a separation step.

[0021] The method for producing a carbonate according to the twelfth invention of the present invention further includes a reaction step in which the sodium carbonate solution obtained in the separation step is reacted with calcium hydroxide to produce calcium carbonate.

[0022] The method for producing a carbonate according to the thirteenth invention of the present invention includes a reaction step in which calcium hydroxide is mixed with a sodium carbonate solution to react the sodium carbonate and calcium hydroxide to produce calcium carbonate, and a drying step in which the precipitate of calcium carbonate obtained in the reaction step is separated and dried.

[0023] The fourteenth invention of the present invention is a method for producing carbonate, in which, in the separation step, a mist containing carbonate is separated from the exhaust gas using a cyclone.

[0024] The method for producing carbonate according to the 15th invention of the present invention uses a caustic soda solution produced from seawater as the alkaline aqueous solution used in the atomization step.

[0025] The sixteenth invention of this invention relates to a method for producing carbonate, in which, in the mixing step, a mist of an alkaline aqueous solution and exhaust gas are mixed using a static mixer.

[0026] The method for producing carbonate according to the 17th invention of the present invention involves mixing an alkaline aqueous solution mist and exhaust gas in a mixer during the mixing step, while maintaining the temperature inside the mixer below the dew point temperature.

[0027] The 18th invention of the present invention further includes a pretreatment step of separating air pollutants contained in exhaust gas, wherein the carbonate is produced using carbon dioxide from the exhaust gas from which the air pollutants have been separated as a raw material in the pretreatment step.

[0028] The 19th invention of the present invention further includes a pretreatment step to remove particulate matter contained in exhaust gas, wherein the carbonate is produced using carbon dioxide from the exhaust gas from which the particulate matter has been separated as a raw material in the pretreatment step.

[0029] The method for producing carbonate according to the 20th invention of the present invention uses an alkaline aqueous solution which is an aqueous solution containing an alkali metal or an alkaline earth metal, or a natural product or waste containing an alkali metal or an alkaline earth metal dissolved in water.

[0030] The carbonate production apparatus according to the 21st invention of the present invention comprises an atomizer that atomizes an alkaline aqueous solution into mist, a mixer that mixes the mist generated by the atomizer with exhaust gas to combine the cations in the mist with carbon dioxide to form a carbonate, and a separator that separates the mist obtained from the mixer from the exhaust gas and recovers the mist containing the carbonate.

[0031] The carbonate production apparatus according to the 22nd invention of the present invention uses an ultrasonic atomizer that vibrates an alkaline aqueous solution ultrasonically to produce a mist.

[0032] The carbonate production apparatus according to the 23rd invention of the present invention is equipped with an ultrasonic atomizer that has a blowing mechanism that blows exhaust gas onto the surface of a liquid column that protrudes from the liquid surface by ultrasonic vibration of an alkaline aqueous solution, thereby mixing the mist with the exhaust gas.

[0033] The carbonate production apparatus according to the 24th invention of the present invention includes an ultrasonic atomizer equipped with a blowing mechanism that uses ultrasonic vibration to create a mist mixture by blowing a conveying gas onto the surface of a liquid column that protrudes from the liquid surface, and a mixer that mixes the mist mixture with exhaust gas.

[0034] The carbonate production apparatus according to the 25th invention of the present invention is an electrostatic atomizer that electrostatically atomizes spray water of an alkaline aqueous solution ejected from a nozzle into a mist.

[0035] The carbonate production apparatus according to the 26th invention of the present invention includes an electrostatic atomizer equipped with a blowing mechanism that blows exhaust gas onto the electrostatically atomized mist to mix the mist and the exhaust gas.

[0036] The carbonate production apparatus according to the 27th invention of the present invention comprises an electrostatic atomizer equipped with a blowing mechanism that blows a conveying gas into the electrostatically atomized mist to form a mist mixture gas, and a mixer that mixes the mist mixture gas with exhaust gas.

[0037] The carbonate production apparatus according to the 28th invention of the present invention uses an atomizer that produces an alkaline aqueous solution mist with an average particle size of 50 μm or less. Furthermore, the carbonate production apparatus according to the 29th invention of the present invention uses an atomizer that produces an alkaline aqueous solution mist with an average particle size of 30 μm or less.

[0038] The carbonate production apparatus according to the 30th invention of the present invention is configured such that the atomizer produces an average particle size of 100 nm or more of the mist of the alkaline aqueous solution.

[0039] In the carbonate production apparatus according to the 31st invention of the present invention, the alkaline aqueous solution that the atomizer produces as mist is a caustic soda solution, and the mixer reacts the caustic soda mist with carbon dioxide gas from the exhaust gas to produce sodium carbonate.

[0040] The carbonate production apparatus according to the 32nd invention of the present invention further comprises a reactor that reacts the sodium carbonate solution obtained in the separator with calcium hydroxide to produce calcium carbonate.

[0041] The carbonate production apparatus according to the 33rd invention of the present invention further comprises a dryer for drying the calcium carbonate produced in the reactor, the reactor comprises a mixing vessel for mixing calcium hydroxide with a sodium carbonate solution and reacting the sodium carbonate and calcium hydroxide to precipitate calcium carbonate, and the dryer dries the calcium carbonate obtained in the mixing vessel to make it into a powder.

[0042] The carbonate production apparatus according to the 34th invention of this invention uses a cyclone as the separator.

[0043] The carbonate production apparatus according to the 35th invention of the present invention uses a caustic soda solution produced from seawater as the alkaline aqueous solution that the atomizer produces as mist.

[0044] The carbonate production apparatus according to the 36th invention of the present invention removes the alkaline aqueous solution that is atomized into a mist with an aqueous solution containing an alkali metal or alkaline earth metal, or an aqueous solution obtained by dissolving a natural product or waste containing an alkali metal or alkaline earth metal in water.

[0045] The carbonate production apparatus according to the 37th invention of this invention uses a static mixer.

[0046] The carbonate production apparatus according to the 38th invention of the present invention further includes a pretreatment unit for separating the air pollutants SOx and NOx from exhaust gas.

[0047] The carbonate production apparatus according to the 39th invention of the present invention further includes a pretreatment unit for removing particulate matter contained in exhaust gas.

[0048] (Embodiment 1) Figure 1 shows a block diagram of a manufacturing apparatus for producing carbonates using carbon dioxide contained in exhaust gases emitted from factory facilities such as power plants and blast furnaces as a raw material. The manufacturing apparatus in this figure produces calcium carbonate. This manufacturing apparatus produces sodium carbonate using carbon dioxide from exhaust gases as a raw material, and then reacts this sodium carbonate with calcium hydroxide to produce calcium carbonate. The calcium carbonate produced by this manufacturing apparatus has a higher commercial value than sodium carbonate and has the advantage of being able to be effectively used in various applications. This apparatus first converts carbon dioxide from exhaust gases into sodium carbonate, and then reacts the sodium carbonate with calcium hydroxide to produce calcium carbonate. The manufacturing apparatus in the figure reacts carbon dioxide from exhaust gases with a mist of caustic soda solution to produce sodium carbonate, and then further reacts the sodium carbonate with calcium hydroxide to produce calcium carbonate. However, the present invention is not limited to producing calcium carbonate, but can produce any carbonate produced by reacting carbon dioxide from exhaust gases with cations in an alkaline aqueous solution, such as sodium carbonate.

[0049] Furthermore, the manufacturing apparatus 100 shown in the block diagram of Figure 1 removes air pollutants such as SO4 from exhaust gas. x And NO x It also includes a pre-treatment unit 4 for separating particulate matter (PM). The pre-treatment unit 4 consists of a PM pre-treatment unit 3 for removing PM and SO x And NO x The manufacturing apparatus 100 includes a pretreatment unit 2 for air pollutants that separates SO2 after removing particulate matter from the exhaust gas. x And NO x The carbon dioxide in the exhaust gas is removed, and carbonates are produced from it.

[0050] The carbonate production apparatus 100 shown in Figure 1 processes particulate matter and SO4 in the pretreatment unit 4. x And NO xCarbonate is produced using carbon dioxide from the separated exhaust gas as a raw material. This production apparatus 100 includes an atomizer 1 that turns an alkaline aqueous solution into a mist, a mixer 6 that mixes the mist generated by the atomizer 1 with carbon dioxide to absorb the carbon dioxide from the exhaust gas into the mist and react the carbon dioxide with the cations in the mist to produce carbonate, and a separator 7 that separates the mist, which has absorbed carbon dioxide in the form of carbonate, from the exhaust gas. Furthermore, the production apparatus 100 in Figure 1 includes a reactor 80 that uses a caustic soda solution in the alkaline aqueous solution to react the carbon dioxide with the caustic soda in the mist to produce sodium carbonate, and further converts the produced sodium carbonate into calcium carbonate, and a controller 5 that controls the atomizer 1.

[0051] (Atomizer 1) Atomizer 1 turns an alkaline aqueous solution into a mist. The cations contained in the mist react with the carbon dioxide in the exhaust gas to produce carbonates. The mist of the alkaline aqueous solution has a small particle size, which increases the surface area per unit weight. The fine mist with a large surface area has a large contact area with the exhaust gas and quickly absorbs the carbon dioxide contained in the exhaust gas. Figure 2 shows a schematic configuration of atomizer 1. Atomizer 1 in Figure 2 turns the alkaline aqueous solution into a fine mist by ultrasonically vibrating the alkaline aqueous solution. Atomizer 1 in Figure 2 is ultrasonic atomizer 1A, which turns an alkaline aqueous solution 9 into a mist by ultrasonic vibration. Ultrasonic atomizer 1A ultrasonically vibrates the alkaline aqueous solution 9 to make a liquid column P protrude from the liquid surface W, and fine mist is dispersed from the surface of the liquid. Ultrasonic atomizer 1A in the figure blows a transport gas onto the surface of the liquid column P of the alkaline aqueous solution 9, dispersing the fine nanomist into the transport gas to make a mist mixture gas. The atomizer 1 comprises an atomization chamber 10 for storing an alkaline aqueous solution 9, an ultrasonic transducer 11 for ultrasonically vibrating the alkaline aqueous solution 9 to cause a liquid column P to protrude from the liquid surface W, a high-frequency power supply 12 connected to the ultrasonic transducer 11 to supply high-frequency power to the ultrasonic transducer 11 for ultrasonic vibration, and a blowing mechanism 20 for blowing a transport gas into the atomization chamber 10 to separate mist from the surface of the liquid column P and form a mist mixed gas.

[0052] The atomizing chamber 10 is a closed chamber that stores an alkaline aqueous solution 9 at a constant liquid level W and generates mist inside. The mist generated in the atomizing chamber 10 is dispersed in the blown transport gas and discharged as a mist mixture. The atomizing chamber 10 can be partially opened without being completely sealed. In the atomizing chamber 10 of the ultrasonic atomizer 1A shown in Figure 2, the supply port 13 for the alkaline aqueous solution 9 is located below the liquid level. An overflow port 14 is opened to control the level of the supplied alkaline aqueous solution 9 to be constant. The alkaline aqueous solution 9 is supplied from the supply port 13 and discharged from the overflow port 14. In this atomizing chamber 10, the liquid level is controlled to be constant by the overflow port 14, but the liquid level can also be kept constant by controlling the amount of alkaline aqueous solution supplied from the supply port 13. The atomizing chamber 10 that controls the liquid level to be constant can maintain the water depth of the alkaline aqueous solution 9, which is ultrasonically vibrated by the ultrasonic transducer 11, at the water depth at which atomization is most efficient.

[0053] The alkaline aqueous solution 9 is supplied to the atomization chamber 10 by the supply mechanism 15. The supply mechanism 15 shown in Figure 2 comprises a solution tank 16 that stores the alkaline aqueous solution 9 supplied to the atomization chamber 10, and a solution pump 17 that supplies the alkaline aqueous solution 9 from the solution tank 16 to the atomization chamber 10. The solution pump 17 has its suction side connected to the solution tank 16 and its discharge side connected to the atomization chamber 10. The supply mechanism 15 continuously supplies the alkaline aqueous solution 9 from the solution tank 16 to the atomization chamber 10 using the solution pump 17.

[0054] As shown in the enlarged cross-sectional view of Figure 3, the ultrasonic transducer 11 is fixed so as to watertightly close the opening 18A provided in the bottom plate 18 of the atomization chamber 10. The ultrasonic transducer 11 has electrodes on its lower surface connected to the high-frequency power supply 12 and is ultrasonically vibrated by the power supplied from the high-frequency power supply 12. The high-frequency power supply 12 is connected to the ultrasonic transducer 11 via lead wires 19 and outputs a high-frequency output to the ultrasonic transducer 11.

[0055] As shown in Figure 2, the blowing mechanism 20 blows a transport gas onto the surface of the liquid column P generated by ultrasonic vibration, blowing the mist off the surface of the liquid column P to form a mist-mixed gas. The liquid column P generated by ultrasonic vibration separates countless fine mist particles from the liquid column surface H and disperses in a highly concentrated mist. The transport gas blown onto the liquid column surface H blows away the mist dispersed in a mist-like form on the liquid column surface H, forming a mist-mixed gas. Quickly blowing away the mist from the liquid column surface H and lowering the mist concentration on the liquid column surface H is effective in increasing atomization efficiency. This is because if the mist concentration on the liquid column surface H is high, the mist cannot be efficiently separated from the surface of the liquid column P. The transport gas blown onto the liquid column surface H separates the mist from the liquid column surface H, and further vaporizes some of the fine mist, which is then discharged as a mist-mixed gas cooled by the heat of vaporization. Increasing the amount of conveying gas blown onto the surface H of the liquid column is effective in increasing the atomization efficiency of the mist. However, when the amount of conveying gas blown onto the surface H of the liquid column is increased, the atomizer 1 reduces the mist concentration of the mist mixture. Therefore, the optimal amount of airflow is set considering both the atomization efficiency and the mist concentration. The blowing mechanism 20 is controlled by the controller 5 to adjust the amount of conveying gas supplied to the atomization chamber 10.

[0056] The atomizer 1 in Figure 2 has an ultrasonic transducer 11 positioned horizontally, causing the liquid column P to protrude vertically from the liquid surface W. The atomizer 1 can also be positioned with the ultrasonic transducer 11 tilted, causing the liquid column P to protrude in a tilted position relative to the liquid surface W. The atomizer 1 in the figure has one ultrasonic transducer 11, but multiple ultrasonic transducers can be used to increase the amount of mist atomized per unit time. The amount of mist generated can also be adjusted by controlling the output of the ultrasonic transducer 11.

[0057] The atomizer 1 in Figure 2 includes an air heater 21 for heating the air used as the conveying gas and a solution heater 22 for heating the alkaline aqueous solution 9. By heating the air and the alkaline aqueous solution 9, the atomizer 1 can increase the atomization efficiency and thus increase the amount of mist generated per unit time. The air heater 21 and the solution heater 22 are controlled by a controller 5 to adjust the temperature of the conveying gas and the alkaline aqueous solution.

[0058] The atomizer 1 uses an aqueous alkaline solution 9 to be atomized into mist, preferably an aqueous alkaline solution with metal ions as cations, and uses an aqueous solution of caustic soda or potassium hydroxide. Power plants and factories installed near the sea preferably use an aqueous solution of caustic soda that can be separated from seawater to reduce the running cost. However, potassium hydroxide can also be used in the aqueous alkaline solution. The device for making the aqueous alkaline solution into potassium hydroxide can effectively utilize the nitrogen component contained in the exhaust gas to form nitrogen potassium fertilizer with the potassium in potassium hydroxide. Nitrogen potassium fertilizer can be effectively used in agriculture as a fertilizer containing both nitrogen and potassium. This manufacturing device is extremely economical because it effectively utilizes the nitrogen component as fertilizer while recovering carbon dioxide gas from the exhaust gas. However, the present invention does not specify the aqueous alkaline solution to be caustic soda or potassium hydroxide, and an aqueous solution containing other alkali metals or alkaline earth metals, or a natural product or waste containing an alkali metal or alkaline earth metal dissolved in water can also be used.

[0059] The atomizer 1 is controlled by the controller 5. In addition to the atomizer 1, the controller 5 also controls the flow rates of the exhaust gas and the mist mixture gas. It is controlled to an environment that suppresses the vaporization of mist inside the mixer 6 with the signals input from the temperature sensor 27 and the humidity sensor 28. Furthermore, the controller 5 adjusts the flow rates of the exhaust gas and the mist mixture gas to control the ratio between the air pollutants SO x and NO x in the exhaust gas and the alkaline component of the aqueous alkaline solution.

[0060] (Mixer 6) Mixer 6 mixes the mist mixture supplied from atomizer 1 with exhaust gas containing carbon dioxide, allowing the mist to absorb the carbon dioxide and react with the cations in the mist to produce a mist containing carbonate. Mixer 6 suppresses mist vaporization by keeping its internal temperature below the dew point temperature. This is because if the mist vaporizes and the liquid component decreases, the efficiency of carbon dioxide dissolving in the liquid mist to form carbonate decreases. Mixer 6 can control its internal temperature to be below the dew point temperature by adjusting the flow rate and temperature of the supplied mist mixture and exhaust gas with controller 5.

[0061] A static mixer is preferably used for mixer 6. Figure 4 shows a schematic perspective view of static mixer 6A. Static mixer 6A has elements 26 arranged in multiple stages inside a pipe member 25. Static mixer 6A mixes the exhaust gas and mist mixture flowing through the pipe member 25 by alternately reversing the flow direction to the right and left through the multiple stages of elements 26. The elements 26 are shaped like rectangular plates twisted 180 degrees, with the inner diameter of the pipe member 25 as the width direction, preferably with a length 1.5 times the width direction. Right elements 26A twisted to the right and left elements 26B twisted to the left are arranged alternately in the flow direction. The adjacent right elements 26A and left elements 26B are positioned in the pipe member 25 in a position perpendicular to each other at their boundary. Each time the static mixer 6A flows into an adjacent element 26, it is divided into two and flows into the downstream element 26, where the direction of rotation is reversed and the mixture flows. The static mixer 6A can more uniformly mix the exhaust gas and mist mixture by increasing the number of alternating right elements 26A and left elements 26B.

[0062] The static mixer 6A is divided into two each time it flows into an adjacent element 26. For example, a static mixer 6A with 20 stages of right element 26A and left element 26B has 220 divisions (1,048,576 times), efficiently mixing the exhaust gas and mist mixture, efficiently bringing the exhaust gas and mist into contact, absorbing the carbon dioxide from the exhaust gas into the mist, and efficiently reacting the cations in the mist with the carbon dioxide to produce a mist containing carbonate. The static mixer 6A shortens the overall length of the right element 26A and left element 26B to 1.5 times its width, and increases the number of elements 26 arranged in multiple stages, thereby efficiently mixing the two fluids and efficiently generating carbonate by reacting carbon dioxide with the cations in the mist while keeping the overall length short. Furthermore, the static mixer 6A can efficiently mix the two fluids by lengthening the elements. The manufacturing apparatus 100 in Figure 1 mixes the mist mixture supplied from the atomizer 1 with the exhaust gas, allowing the mist to absorb carbon dioxide, and then reacts the cations in the mist with the carbon dioxide to form a carbonate.

[0063] (Separator 7) The separator 7 separates and recovers the carbonate-containing mist from the exhaust gas. The separator 7 recovers the mist and the carbonate solution. Preferably, the separator 7 uses a cyclone 70. The cyclone 70 shown in Figure 5 is cylindrical, with a tapered section 72 that narrows at the bottom connected to the lower end of a cylindrical section 71. The cyclone 70 rotates the exhaust gas containing the mist in a vortex inside, separating the mist from the exhaust gas by centrifugal force. The mist is separated by the action of centrifugal force of the cyclone 70. The mist moves outward while rotating due to the centrifugal force. The centrifugal force acting on the mist increases in proportion to its mass. The mass of the mist is greater than that of the exhaust gas, and furthermore, the mass of the mist increases in proportion to the cube of the particle size. Micron-order mist generated by ultrasonic vibration has an extremely large mass compared to nano-order mist, which can increase the separation efficiency of the cyclone 70. The ultrasonic atomizer 1A efficiently generates mist on the order of microns, and the mist generated by the ultrasonic atomizer 1A can be efficiently separated from the exhaust gas by the cyclone 70.

[0064] The cyclone 70 has an inlet duct 73 connected to the cylindrical section 71 to allow the mist-containing exhaust gas, which is a mixture of exhaust gas and mist, to flow in tangentially, in order to rotate the mist-containing exhaust gas at high speed. The mist-containing exhaust gas flowing tangentially from the inlet duct 73 into the cylindrical section 71 rotates at high speed inside the cylindrical section 71. The mist-containing exhaust gas rotating at high speed in the cylindrical section 71 moves the mist toward the outer circumference by centrifugal force. The mist moving toward the outer circumference comes into contact with the inner surface of the cylindrical section 71 and flows down in a liquid state along the inner surface of the tapered section 72. The tapered section 72 is provided with a liquid outlet 74 at its lower end to discharge the flowing liquid to the outside. Below the liquid outlet 74 is a liquid tank 76 for storing a carbonate solution. The exhaust gas, from which the mist has been separated, is discharged to the outside through an exhaust duct 75 which is positioned vertically and extends axially from the center of the cylindrical section 71. Exhaust gas, which has a lower specific gravity than mist, experiences less centrifugal force due to rotation and can be exhausted to the outside from the center of the cylindrical section 71.

[0065] The separator 7 described above separates mist from exhaust gas with a single cyclone 70, but the separator can also separate mist more efficiently by using a multi-cyclone, which connects multiple cyclones in series and parallel. In a multi-cyclone, the discharge cyclone is connected to the inlet cyclone. The discharge cyclone has multiple smaller cyclones connected in parallel to the inlet cyclone. The inlet cyclone branches off the exhaust duct and connects it to the inlet duct of the discharge cyclone. The exhaust gas containing mist, from which the mist has been separated by the inlet cyclone, branches off and flows into the discharge cyclone. The discharge cyclone further separates mist from the incoming mist-containing exhaust gas. The multi-cyclone efficiently separates mist by separating it from the mist-containing exhaust gas using both the inlet and discharge cyclones.

[0066] The apparatus using a cyclone 70 as the separator 7 has the advantage of being able to efficiently separate mist with a simple structure. However, the present invention does not limit the separator 7 to a cyclone 70, and all other separators that can separate mist from mist-containing exhaust gas, such as electrostatic separators and demisters that are already in use, can also be used. An electrostatic separator has a discharge electrode that charges the mist in the passage of the mist-containing exhaust gas, and the charged mist is attracted to a current collector electrode by the action of static electricity and separated. Because the electrostatic separator attracts mist by the action of static electricity, it can efficiently separate even finer mist.

[0067] (Reactor 80) A liquid tank 76 located below the cyclone 70 collects the mist and stores a carbonate solution. In a device that uses a caustic soda solution as an alkaline aqueous solution for the mist, the caustic soda in the mist reacts with the carbon dioxide in the exhaust gas to produce sodium carbonate. Therefore, this device stores a sodium carbonate solution as a carbonate solution in the liquid tank 76. The manufacturing apparatus 100 in Figure 1 includes a reactor 80 that converts sodium carbonate into calcium carbonate, which has a higher commercial value.

[0068] As shown in Figure 6, reactor 80 mixes calcium hydroxide with a sodium carbonate solution and reacts the sodium carbonate with calcium hydroxide to produce calcium carbonate. In reactor 80 in Figure 6, calcium hydroxide is added to the sodium carbonate solution supplied to the mixing container 81 and mixed to produce calcium carbonate. The added calcium hydroxide dissolves and reacts with sodium carbonate to produce calcium carbonate, as shown in the reaction equation (1) below. The produced calcium carbonate has low solubility and precipitates at the bottom of the mixing container 81. Sodium hydroxide (caustic soda) has high solubility and dissolves in the liquid. Reactor 80 produces calcium carbonate by mixing calcium hydroxide with a sodium carbonate solution of approximately the same molar concentration. The calcium carbonate precipitated at the bottom of the mixing container 81 is collected from the mixing container 81, the water is removed by methods such as filtration, and then it is dried in a dryer 82 to be recovered as powdered calcium carbonate. Na2CO3+Ca(OH)2→CaCO3+2NaOH……(1)

[0069] (Controller 5) The controller 5 controls the flow rate and temperature of the transport gas and exhaust gas supplied to the atomizer 1, taking into account the atomization efficiency and mist concentration of the atomizer 1. The controller 5 also controls the air heater 21, which heats the air in the atomizer 1, and the solution heater 22, which heats the alkaline aqueous solution 9. By heating the air and the alkaline aqueous solution 9, the atomizer 1 can increase its atomization efficiency and generate a larger amount of mist per unit time. The air heater 21 and solution heater 22 are controlled by the controller 5 to adjust the air temperature and alkaline aqueous solution temperature.

[0070] In addition to controlling the atomizer 1, the controller 5 also controls the flow rate of the exhaust gas and mist mixture supplied to the mixer 6. For example, the controller 5 controls the environment inside the mixer 6 to suppress mist vaporization based on signals received from the temperature sensor 27 and humidity sensor 28 installed in the mixer 6. Furthermore, the controller 5 adjusts the flow rate of the exhaust gas and mist mixture to control the ratio of CO2 in the exhaust gas to the alkaline component of the alkaline aqueous solution. For example, when generating sodium carbonate by reacting the mist, which is made from a caustic soda solution using an alkaline aqueous solution, with CO2 in the exhaust gas, the controller 5 adjusts the amount of mist mixture supplied to the mixer 6 using the supply fan 29 so that sodium carbonate can be efficiently generated with a specific ratio of carbon dioxide to caustic soda. The controller 5 can also detect the pH of the mist recovered by the separator 7 and control the amount of mist mixture supplied. This controller 5 controls the flow rate of the mist mixture supplied from the atomizer 1 to the mixer 6.

[0071] The controller 5 adjusts the temperature and flow rate of the mist mixture and exhaust gas supplied to the mixer 6 to suppress the vaporization of mist inside the mixer 6. Furthermore, the controller 5 can control the temperature and humidity of the mist mixture supplied to the mixer 6 by adjusting the flow rate and temperature of the conveying gas supplied to the atomizer 1, and by adjusting the temperature of the ultrasonically vibrating alkaline aqueous solution. When the temperature of the mist mixture supplied to the mixer 6 is high and the air flow rate is high, the relative humidity inside the mixer 6 decreases, making it easier for the mist to vaporize. Therefore, the controller 5 detects the temperature and humidity inside the mixer 6 and adjusts the air heater 21 and solution heater 22 so that the internal relative humidity is within the set range, and also controls the flow rate of the air supplied to the atomizer 1 with the blower mechanism 20. Furthermore, the controller 5 also adjusts the flow rate of the exhaust gas and the flow rate of the outside air supplied to the exhaust gas to effectively suppress the vaporization of mist by keeping the relative humidity inside the mixer 6 within the set range, preferably a supersaturated state with a relative humidity of 100% or more, i.e., below the dew point temperature.

[0072] The atomizer 1 can increase atomization efficiency by increasing the airflow rate and air temperature supplied to the liquid column P, and further increasing the temperature by heating the alkaline aqueous solution 9. Therefore, the controller 5 adjusts the airflow rate and temperature supplied to the liquid column P, taking atomization efficiency into consideration. Increasing the airflow rate and temperature increases atomization efficiency, but also increases the proportion of mist that vaporizes in the mixer 6. Accordingly, the controller 5 detects the temperature and humidity in the mixer 6 and adjusts the airflow rate and temperature supplied by the atomizer 1 to the liquid column P. Preferably, the controller 5 increases the airflow rate and temperature while maintaining a supersaturated or nearly supersaturated state of moisture in the mixer 6 to increase atomization efficiency and suppress mist vaporization. The atomizer 1 equipped with a solution heater 22 increases the temperature of the heated alkaline aqueous solution within a range that maintains a supersaturated or nearly supersaturated state in the mixer 6.

[0073] The flow rate and temperature of the exhaust gas supplied to mixer 6 affect the amount of mist vaporized inside mixer 6. High-temperature exhaust gas containing water vapor can be cooled to below the dew point temperature before being supplied to mixer 6 to suppress mist vaporization inside mixer 6. When high-temperature, low-humidity exhaust gas is supplied to mixer 6, the relative humidity inside mixer 6 decreases, promoting mist vaporization. In particular, when a large amount of low-humidity exhaust gas is supplied to mixer 6, the relative humidity inside mixer 6 decreases, promoting mist vaporization. Therefore, the system controls the system to maintain the relative humidity inside mixer 6 above the set range by cooling the high-temperature exhaust gas to increase its relative humidity, or by lowering the relative humidity of the mist mixture supplied from atomizer 1. To suppress mist vaporization by keeping the temperature inside the mixer below the dew point temperature, controller 5 detects the temperature and humidity of the mixer and controls the temperature, humidity, and flow rate of the exhaust gas and mist mixture supplied to mixer 6.

[0074] (Pre-processing machine 4) The pretreatment unit 4 separates particulate matter and air pollutants from exhaust gases emitted from power plants, blast furnaces, diesel engines, etc. The pretreatment unit 4 comprises a PM pretreatment unit 3 for separating particulate matter (PM) and an air pollutant pretreatment unit 2 for separating air pollutants. In the manufacturing apparatus 100 shown in Figure 1, particulate matter is separated from the exhaust gas in the PM pretreatment unit 3, and then SO4 is treated in the air pollutant pretreatment unit 2. x And NO x The carbon dioxide in the exhaust gas is separated to produce carbonates.

[0075] (PM pre-treatment machine 3) The PM pretreatment unit 3 can efficiently remove ultrafine particles using an electrostatic precipitator. As shown in Figure 7, the electrostatic precipitator 30 is equipped with a discharge electrode 31, a dust collection electrode 32, and a power supply 33, and separates particulate matter from exhaust gas by the action of static electricity.

[0076] The discharge electrode 31 is arranged in the air circulation path 35 with the positive electrode 31A and the negative electrode 31B facing each other. The negative electrode 31B consists of two thin metal wires arranged parallel to each other with an insulator (not shown) in between. A plate-shaped positive electrode 31A is placed between the two negative electrodes 31B. The plate-shaped positive electrode 31A is fixed parallel to the airflow direction so that air can pass through smoothly. The positive electrode 31A is directly connected to the power supply 33, and the negative electrode 31B is connected via a switch 34. The power supply 33 applies a corona discharge voltage, for example, 3000 to 10000V, to the positive electrode 31A and the negative electrode 31B. When the switch 34 is turned on, a negative high voltage is applied to the negative electrode 31B. The positive electrode 31A is connected to the ground side of the power supply. Under normal operating conditions, the linear negative electrode 31B is connected to the negative side of the power supply 33, and the plate-shaped positive electrode 31A is connected to the positive side of the power supply 33 to perform a negative corona discharge. This is because negative corona discharge generates a higher current compared to positive corona discharge, allowing for effective charging of particulate matter in the air. However, it is also possible to connect the linear electrode as the positive electrode to the positive side of the power supply and the plate-shaped electrode as the negative electrode to the negative side of the power supply.

[0077] The dust collection electrode 32 is located in the air circulation path 35, on the air discharge side of the discharge electrode 31. The dust collection electrode 32 attracts particulate matter charged by the discharge electrode 31 using electrostatic attraction. Therefore, the dust collection electrode 32 consists of plate-shaped electrodes arranged parallel to each other with an insulating material in between. The plate-shaped electrodes are connected to a power supply 33 and are charged by the power supply 33 to a voltage capable of attracting particulate matter, for example, 2000 to 15000V.

[0078] The electrostatic precipitator 30 described above charges particulate matter contained in exhaust gas with a discharge electrode 31, and collects the charged particulate matter by attracting it to the surface of a dust collection electrode 32 through the action of static electricity. The electrostatic precipitator 30 can efficiently collect ultrafine particles contained in exhaust gas. However, a PM pretreatment machine does not necessarily have to use an electrostatic precipitator; any other device that can separate particulate matter, such as a bag filter or cyclone, can also be used.

[0079] (Air pollutant pretreatment unit 2) This air pollutant pretreatment unit 2 can use all pretreatment units that are currently in use and will be developed in the future. Therefore, the present invention does not specify air pollutant pretreatment unit 2, but preferred air pollutant pretreatment units are exemplified below.

[0080] The air pollutant pretreatment unit 2 in Figure 8, similar to the carbonate production device 100, mixes exhaust gas with mist to produce SO x And NO x The SO2 is absorbed and separated into a mist. This air pollutant pretreatment unit 2 consists of an atomizer 1 that turns an alkaline aqueous solution into a mist, and a unit that mixes the mist generated by atomizer 1 with the exhaust gas to remove SO2 from the exhaust gas. x And NO x The system includes a mixer 6 that absorbs the fumes into a mist, and a separator 7 that recovers the mist after it has absorbed the fumes. The atomizer 1, mixer 6, and separator 7 can have the same structure as the carbonate production apparatus 100. The atomizer 1, for example, turns a caustic soda solution into a mist. The caustic soda solution mist is mixed with exhaust gas in the mixer 6 to produce SO2. x And NO x It absorbs and reacts with sodium metal ions. SO x And NO x The mist that has absorbed the SO2 is recovered by the cyclone 70 of separator 7, and SO2 is extracted from the exhaust gas. x And NO x They are separated.

[0081] Air pollutant pretreatment unit 2 mixes exhaust gas with a mist of caustic soda solution to produce SO2 x And NO x Separate SO x And NO x Since it is more reactive than carbon dioxide, the exhaust gas is mixed with a mist of caustic soda solution, and SO4 is extracted from the exhaust gas while leaving some carbon dioxide behind. x And NO x It can be separated.

[0082] The air pollutant pretreatment unit 2 shown in Figure 8 consists of a first treatment unit 2A and a second treatment unit 2B. In this air pollutant pretreatment unit 2, the second treatment unit 2B is connected to the discharge side of the first treatment unit 2A, and the first treatment unit 2A mainly processes SO4 from exhaust gas. x The second processor 2B separates the two, and the second processor 2B mainly processes NO x Separate SO x NO x It has a higher reactivity with the caustic soda solution and is efficiently absorbed upon contact with the mist. The second processor 2B processes SO in the first processor 2A. x NO is separated from the exhaust gas. x Separate them.

[0083] In Figure 8, the air pollutant pretreatment unit 2 has an oxidizer 8 connected between the first treatment unit 2A and the second treatment unit 2B. The oxidizer 8 oxidizes NO1 in the exhaust gas to NO2. The exhaust gas is NO x The exhaust gas contains NO1 and NO2, but NO1 is not easily soluble in water. The air pollutant pretreatment unit 2 in Figure 8 is equipped with an oxidizer 8 that mixes outside air as an oxygen-containing gas with the exhaust gas in order to oxidize the NO1 in the exhaust gas into NO2, which is easily soluble. The oxidizer 8 mixes outside air as an oxygen-containing gas with the exhaust gas and oxidizes NO1 to NO2. NO1 in exhaust gas is easily oxidized and combines with oxygen contained in the air to become NO2. The outside air mixed with the exhaust gas oxidizes NO1 and also lowers the temperature of the high-temperature exhaust gas discharged from blast furnaces, power plants, etc., bringing the exhaust gas below the dew point temperature. When the temperature of the exhaust gas drops below the dew point temperature, the supersaturated water vapor liquefies into fine water droplets. Therefore, the exhaust gas mixed with outside air has NO1 converted to NO2 and is in a supersaturated state as its temperature drops below the dew point temperature. The temperature of the exhaust gas that is lowered by the outside air can be made even lower by increasing the amount of outside air mixed in. The amount of outside air mixed is preferably adjusted so that the exhaust gas temperature is below the dew point temperature, for example, 150°C or less.

[0084] The air pollutant pretreatment unit 2 in Figure 8 primarily processes NO x An oxidizer 8 is connected to the inlet side of the second processing machine 2B that separates SO. xThe NO1 contained in the separated exhaust gas is converted to NO2 and supplied to the second treatment unit 2B. This air pollutant pretreatment unit 2 has an oxidizer 8 connected between the first treatment unit 2A and the second treatment unit 2B, but the oxidizer 8 can be connected to the inlet side of the first treatment unit 2A to oxidize NO1 to NO2. Therefore, the oxidizer can also be connected to the inlet side of the first treatment unit 2A or to the inlet side of the PM pretreatment unit 3.

[0085] The above air pollutant pretreatment unit 2 mixes the caustic soda solution as a mist with the exhaust gas to produce SO2. x And NO x This air pollutant pretreatment unit 2 mixes fine mist with exhaust gas, so the contact area between the caustic soda solution and the exhaust gas is large, separating the air pollutant SO2. x And NO x It can efficiently separate SOx and NOx. However, the air pollutant pretreatment unit 2 can also separate SOx and NOx from exhaust gas using conventional wet scrubbers, etc. The wet scrubber 78 shown in Figure 9 has a caustic soda solution, etc., in the exhaust gas passage. x And NO x An aqueous solution that reacts with and absorbs is sprayed from nozzle 79, and the sprayed atomized caustic soda solution comes into contact with the exhaust gas, SO x And NO x It is separated by aspirating it into a caustic soda solution.

[0086] The carbonate production apparatus 100 shown in Figure 1 produces carbonate using carbon dioxide from exhaust gas as a raw material in the following process. Since the production apparatus 100 in this figure is equipped with a pretreatment unit 4 on the inlet side, particulate matter is removed from the exhaust gas, and air pollutants SO4 are removed. x And NO x The carbon dioxide in the exhaust gas is removed, and carbonates are produced from it.

[0087] [Pre-treatment process] In the pretreatment process, particulate matter and air pollutants such as SO4 are removed from the exhaust gas supplied to the mixer 6. x And NO xThe following is done: The manufacturing apparatus 100 shown in Figure 1 has a PM pretreatment unit 3 and an air pollutant pretreatment unit 2 on the supply side of the mixer 6. After separating and removing particulate matter from the exhaust gas in the PM pretreatment unit 3, the air pollutant pretreatment unit 2 removes the air pollutant SO2. x And NO x Separate and remove it.

[0088] [Atomization process] In this process, the atomizer 1 turns the alkaline aqueous solution into a mist. The atomizer 1 mixes the alkaline aqueous solution as a mist with a conveyor gas to form a mist mixture. The atomizer 1 turns the alkaline aqueous solution into a caustic soda solution as a mist. The atomizer 1 is not limited to using a caustic soda solution as the alkaline aqueous solution to be misted; it can also use alkaline aqueous solutions of other alkali metals such as potassium hydroxide, as well as aqueous solutions containing alkaline earth metals, or natural products or waste containing alkali metals or alkaline earth metals dissolved in water. As shown in Figure 2, the atomizer 1 generates mist by blowing the conveyor gas onto the surface of a liquid column P that protrudes from the liquid surface using ultrasonic vibration with an ultrasonic transducer 11. The conveyor gas blows the mist away from the surface of the liquid column P to form a mist mixture. The absorption of carbon dioxide can be controlled by adjusting the sodium hydroxide concentration of the mist. The concentration of the alkaline aqueous solution in the mist should be, for example, 1 vol% or higher. By increasing the concentration of the alkaline aqueous solution in the mist, the absorption of air pollutants can be made more efficient. Therefore, the concentration of the alkaline aqueous solution in the mist should preferably be as high as possible, but not so high that sodium hydroxide or potassium hydroxide becomes supersaturated.

[0089] [Mixing process] The mixing process involves supplying the exhaust gas and mist mixture to the mixer 6 for mixing, allowing the carbon dioxide from the exhaust gas to be absorbed by the mist, and combining the cations in the mist with the carbon dioxide to form a carbonate. For example, in the mixing process, a static mixer 6A is used to mix the exhaust gas and mist mixture, allowing the carbon dioxide from the exhaust gas to be absorbed by the mist. The static mixer 6A of the mixer 6 mixes the mist mixture supplied from the atomizer 1 with the exhaust gas, allowing the carbon dioxide from the exhaust gas to be absorbed by the alkaline aqueous solution mist. The carbon dioxide from the exhaust gas combines with the cations in the mist to form a carbonate, resulting in a mist containing carbonate.

[0090] [Separation process] The separation process involves separating the mist containing carbonates generated in the mixing process from the exhaust gas using a separator 7 connected to the discharge side of the mixer 6. In the separation process, for example, a cyclone 70 is used in the separator 7 to separate the mist containing carbonates from the exhaust gas. In the manufacturing apparatus 100 shown in Figure 1, the alkaline component of the mist is a caustic soda solution, so the caustic soda in the mist reacts with the carbon dioxide in the exhaust gas to produce sodium carbonate as a carbonate. Therefore, in this separation process, a sodium carbonate solution is obtained as the carbonate solution.

[0091] The manufacturing apparatus 100 in Figure 1 separates carbonates from exhaust gas by absorbing carbon dioxide from the exhaust gas into mist through the above process. The controller 5 controls the atomizer 1 and mixer 6 so that carbon dioxide from the exhaust gas can be efficiently absorbed and separated into mist. The controller 5 detects the temperature and humidity inside the mixer 6 and adjusts the air temperature of the conveying gas supplied to the atomizer 1, the air flow rate, and the temperature at which the alkaline aqueous solution is heated, so that the temperature inside the mixer 6 is preferably kept below the dew point temperature and the alkaline aqueous solution can be efficiently atomized into mist. Furthermore, the controller 5 also adjusts the flow rate ratio and temperature of the exhaust gas and the conveying gas, bringing the exhaust gas and mist into contact inside the mixer 6 to efficiently absorb carbon dioxide into the mist.

[0092] [Reaction Process] Furthermore, in the reaction step, the sodium carbonate solution obtained in the separation step is reacted with calcium hydroxide in the reactor 80 to produce calcium carbonate. The manufacturing apparatus 100 in Figure 1 produces calcium carbonate with higher commercial value by mixing calcium hydroxide with the sodium carbonate obtained in the separation step and reacting them. In this reaction step, calcium hydroxide is mixed with the sodium carbonate solution in the mixing container 81, and the sodium carbonate and calcium hydroxide react to form calcium carbonate. Furthermore, the precipitate of calcium carbonate obtained in the reaction step is separated, and powdered calcium carbonate is obtained by drying it in a dryer in the drying step.

[0093] (Embodiment 2) The carbonate production apparatus 200 in Figure 10 supplies exhaust gas to an atomizer 1. This atomizer is equipped with a blowing mechanism 20 that blows exhaust gas onto the surface of a liquid column P generated by ultrasonic vibrations, and the blown exhaust gas blows the mist off the surface of the liquid column P to become mist-containing exhaust gas. If the exhaust gas supplied to the atomizer 1 is at a high temperature, it will vaporize the mist and reduce the atomization efficiency. Therefore, the exhaust gas supplied to the atomizer 1 is supplied with controlled temperature. High-temperature exhaust gas is cooled to a temperature below the dew point temperature inside the atomizer 1 before being supplied to the atomizer 1. By forcibly cooling the exhaust gas, the water vapor it contains can be removed by condensation, thus reducing the absolute humidity before it can be supplied to the atomizer 1. Exhaust gas with controlled temperature and low humidity does not vaporize the mist inside the atomizer 1, and the decrease in atomization efficiency caused by mist vaporization can be suppressed. However, since the atomization efficiency of atomizer 1 decreases if the temperature of the supplied exhaust gas is too low, the exhaust gas supplied to atomizer 1 is cooled and controlled to a temperature that does not reduce its atomization efficiency.

[0094] The manufacturing apparatus 200 in Figure 10 mixes exhaust gas and mist in the atomizer 1 to produce mist-containing exhaust gas, so the atomizer 1 can be used in conjunction with a mixer 6 that mixes mist and carbon dioxide. In a manufacturing apparatus that uses the atomizer 1 in conjunction with a mixer 6, carbon dioxide and mist can be mixed without connecting a dedicated mixer to the next stage after the atomizer 1, and carbonate can be produced by reacting the carbon dioxide in the exhaust gas with the cations in the mist. However, even in this manufacturing apparatus, preferably as shown in Figure 10, the mixer 6 is connected to the discharge side of the atomizer 1, and the mist-containing exhaust gas mixed in the atomizer 1 is further mixed in the mixer 6 to mix the exhaust gas and mist more efficiently and produce carbonate. In the manufacturing apparatus 200 that supplies exhaust gas to the atomizer 1, as in the manufacturing apparatus 100 in Figure 1, no conveying gas is supplied to the mixer 6, so the mist concentration in the mixer 6 can be increased and carbonate can be produced efficiently from carbon dioxide.

[0095] (Embodiments 3 and 4) The manufacturing apparatuses 100 and 200 described above use ultrasonic vibration to turn an alkaline aqueous solution into a fine mist. However, the manufacturing apparatuses of embodiments 3 and 4 use an electrostatic atomizer instead of the atomizer in the manufacturing apparatuses of embodiments 1 and 2 described above to generate mist of the alkaline aqueous solution. As shown in Figure 11, the electrostatic atomizer has a sprayer 41 consisting of multiple nozzles installed at the top of a closed spray case 47, and sprays the alkaline aqueous solution from top to bottom. Furthermore, the electrostatic atomizer 1B has an atomizing electrode 42 placed inside the spray case 47 that turns the sprayed water from the sprayer 41 into a fine mist by the action of static electricity.

[0096] The electrostatic atomizer 1B shown in Figure 11 has a sprayer 41 consisting of multiple spray units 50 installed in a spray case 47. The spray unit 50 is shown in Figure 12. The spray unit 50 shown in this figure has multiple capillary tubes 53 fixed in parallel to a nozzle block 54. The capillary tubes 53 are thin metal tubes with an inner diameter of 0.1 mmφ to 0.2 mmφ, and they spray a pressurized alkaline aqueous solution from their tips into a mist.

[0097] The nozzle block 54 has a flange-shaped flange 54a on its outer circumference and multiple capillary tubes 53 in its center. In the nozzle block 54 shown in Figure 12, a plate portion 54B that fixes the capillary tubes 53 is screwed to a main body portion 54A which has the flange 54a. The plate portion 54B has through holes 54x through which the capillary tubes 53 are inserted. The inner shape of the through holes 54x is approximately equal to the outer shape of the capillary tubes 53, and the capillary tubes 53 are inserted with almost no gaps. To prevent liquid leakage between the capillary tubes 53 and the through holes 54x, a packing 55 is placed on the inner surface of the plate portion 54B. The packing 55 is a rubber-like elastic material that airtightly seals the gap between the capillary tubes 53 and the plate portion 54B. A clamping plate 56 is placed to fix the packing 55 in a pressed state. The packing 55 is crushed between the plate portion 54B and the clamping plate 56 and fixed to the main body portion 54A. The clamping plate 56 also has through holes 56x. The clamping plate 56 is positioned on the stepped portion 54b of the main body portion 54A and is fixed to the main body portion 54A by elastically pressing the packing 55 against the plate portion 54B which is fixed to the main body portion 54A. Furthermore, the main body portion 54A has a cylindrical portion 54c that protrudes from the rear. The cylindrical portion 54c has an internal shape that allows multiple capillary tubes 53 to be arranged inside, and an external shape that has male threads 54d on the outside. The main body portion 54A has the capillary tubes 53 arranged inside this cylindrical portion 54c. The cylindrical portion 54c is connected to a water supply socket 57 for supplying an alkaline aqueous solution at its rear end.

[0098] The nozzle block 54 in Figure 12 has multiple through holes 54x provided in the plate portion 54B arranged in multiple rows in a ring shape. The capillary tube 53 protrudes from the nozzle block 54, with its tip serving as a discharge projection 51 and its internal central hole serving as a fine spray hole 52. The number of capillary tubes 53 fixed to the nozzle block 54 determines the number of fine spray holes 52 in the spray unit 50. The spray unit 50 preferably has 10 or more, preferably 20 or more, and more preferably 30 or more fine spray holes 52 to increase the amount of mist sprayed per unit time by one set of spray units 50. If the number of fine spray holes 52 is too large, the overall size of the spray unit 50 will be large, so the spray unit 50 is provided with 100 or fewer fine spray holes 52. The spray unit 50 shown in Figure 12 has a capillary tube 53 positioned in the center of the nozzle block 54 that protrudes more than the capillary tube 53 on the outer circumference, so that the tip surface formed by the large amount of capillary tube 53 is convex in the center. However, the spray unit can also have the capillary tubes protruding at the same length, so that the tip surface formed by the large amount of capillary tube is flat.

[0099] The spraying unit 50 described above is equipped with a tubular structure consisting of numerous capillary tubes 53, and sprays an alkaline aqueous solution into a mist from each capillary tube 53. The spraying unit can also be made of a perforated plate with numerous fine spray holes instead of capillary tubes. The perforated plate is made of a conductive material such as metal. This perforated plate can be made by creating fine spray holes in a metal plate with a laser. Furthermore, the perforated plate can also be made of sintered metal with fine spray holes. The conductive perforated plate can be connected to a high-voltage power supply so that a high voltage can be applied between it and the atomizing electrode. However, the perforated plate does not necessarily have to be made of a conductive material. This is because the alkaline aqueous solution is conductive, so a high voltage can be applied between the alkaline aqueous solution sprayed from the spray holes and the atomizing electrode, and the sprayed mist can be atomized by the action of static electricity. Therefore, the perforated plate can also be made of a continuous-cell plastic foam with fine spray holes.

[0100] The spray case 47 is insulated from the sprayer 41 and has an atomizing electrode 42 installed therein. The atomizing electrode 42 is at a high voltage relative to the sprayer 41. Therefore, the atomizing electrode 42 and the sprayer 41 are insulated from each other and fixed to the spray case 47. In electrostatic atomizer 1B, where the sprayer is fixed to the metal spray case without insulation, the atomizing electrode is insulated from the spray case. Also, in electrostatic atomizer 1B where the sprayer is insulated from the spray case, the atomizing electrode is fixed to the spray case. However, it is also possible to insulate and fix both the sprayer and the atomizing electrode to the spray case.

[0101] The atomizing electrode 42 discharges electricity with the discharge projection 51 of the sprayer 41, atomizing the mist sprayed from the sprayer 41 into fine particles. This atomizing electrode 42 is positioned in front of the fine spray holes 52, away from them in the direction of mist spraying. The atomizing electrode 42 in Figure 11 is an annular metal ring 42A located on the outer circumference of the nozzle block 54, and is positioned on the outer circumference of the multiple capillary tubes 53 fixed to the nozzle block 54. The atomizing electrode 42, which is a metal ring as shown in Figure 11, is in the passage of the transported gas blown out from the outlet hole 64, and the amount of mist adhering to the atomizing electrode 42 by the blown transported gas can be reduced.

[0102] In addition, a metal mesh can be used as the atomizing electrode. The metal mesh atomizing electrode is positioned away from the discharge projection 51 in the direction of mist spraying. The metal mesh atomizing electrode discharges uniformly with each discharge projection 51, enabling the mist sprayed from each fine spray hole 52 to be atomized into fine particles.

[0103] The atomizing electrode 42 is positioned in front of each spraying unit 50. In the electrostatic atomizer 1B shown in Figure 11, the atomizer 41 sprays mist downwards, so the atomizing electrode 42 is positioned below the spraying unit 50.

[0104] The high-voltage power supply 43 applies a high voltage between the spraying unit 50 and the atomizing electrode 42. The high-voltage power supply 43 is a DC power supply, with the positive side connected to the atomizing electrode 42 and the negative side connected to the spraying unit 50. However, it is also possible to connect the positive side to the spraying unit and the negative side to the atomizing electrode.

[0105] The electrostatic atomizer 1B in Figure 11 has a closed chamber at the top of the spray case 47, which serves as an air chamber 62. To partition the air chamber 62, a partition wall 63 is fixed airtightly to the top of the spray case 47. The partition wall 63 divides the inside of the spray case 47 into the air chamber 62 and the spray chamber 61, and also serves as a fixing part for fixing the sprayer 41, fixing multiple spray units 50 in place. The spray units 50 of the sprayer 41 are fixed to the partition wall 63, which is the fixing part, so that they spray mist into the spray chamber 61. As shown in Figure 12, the spray units 50 are fixed to the partition wall 63 in a detachable manner via connecting bolts 58 that pass through connecting holes 54e opened in the flange 54a of the nozzle block 54.

[0106] The air chamber 62 has a closed structure and is connected to a blower mechanism 67, which is a gas supply mechanism. The conveyed gas blown from the blower mechanism 67 is ejected into the spray chamber 61 through a blower hole 64 that penetrates the partition wall 63. The blower hole 64 is a slit-shaped through-hole and is provided between the spray units 50 so that the ejected conveyed gas is blown around each spray unit 50. However, the blower hole does not necessarily have to be slit-shaped. Multiple circular or polygonal through-holes can be provided between the spray units to eject the conveyed gas between the spray units. The conveyed gas ejected from the blower hole 64 into the spray chamber 61 transports the atomized mist. In Figure 11, the spray case 47 has blower holes 64 provided between adjacent spray units 50. The transported gas ejected from the outlet 64 into the spray chamber 61 is mixed with the mist that has been sprayed from the spray unit 50 and atomized into fine particles by the atomizing electrode 42, and the resulting mist mixture is supplied to the static mixer 6A.

[0107] As shown in Figure 11, the sprayer 41 fixes the spray unit 50 to the spray chamber 61 side of the partition wall 63 and sprays mist into the spray chamber 61. The sprayer 41 is connected to a pump 65 that supplies an alkaline aqueous solution under pressure. The pump 65 pressurizes the alkaline aqueous solution 9 stored in the liquid tank 66 and supplies it to the spray unit 50. The pump 65 filters the alkaline aqueous solution 9 with a filter and supplies it to the sprayer 41. The filter removes foreign matter that clogs the sprayer 41. The pump 65 can increase the discharge pressure to increase the flow rate of the alkaline aqueous solution sprayed from the spray unit 50 and reduce the average particle size of the mist. However, the average particle size of the mist changes not only with the pressure of the alkaline aqueous solution supplied from the pump 65 but also with the structure of the spray unit 50. Therefore, the pressure at which the pump 65 pressurizes the alkaline aqueous solution and supplies it to the spray unit 50 is set to an optimal value considering the structure of the spray unit 50 and the required mist particle size, but is preferably 0.1 MPa or higher, preferably 0.2 MPa or higher, and more preferably 0.3 MPa or higher. If the pressure of the alkaline aqueous solution supplied by the pump 65 to the spray unit 50 is high, the pump 65 becomes expensive, and the power consumption of the motor operating the pump 65 increases, resulting in higher running costs. Therefore, the pressure of the alkaline aqueous solution supplied by the pump 65 to the spray unit 50 is, for example, 1 MPa or less, preferably 0.8 MPa or less, and more preferably 0.7 MPa or less. The pressure at which the pump 65 pressurizes the alkaline aqueous solution and supplies it to the spray unit 50 is preferably 0.3 MPa to 0.6 MPa, and preferably the average mist particle size is 50 μm or less, preferably 30 μm or less, and 100 nm or more. [Industrial applicability]

[0108] The carbonate production method and apparatus of the present invention are suitably used as a method and apparatus for producing carbonates using carbon dioxide contained in exhaust gas from blast furnaces, power plants, etc. as a raw material. [Explanation of Symbols]

[0109] 100, 200...manufacturing equipment 1…Atomizer 1A…Ultrasonic atomizer 1B…Electrostatic atomizer 2… Pretreatment unit for air pollutants 2A...First processing machine 2B...Second processing unit 3…PM pre-processing machine 4…Pre-processing machine 5…Controller 6… Mixer 6A…Static Mixer 7...Separator 8… Oxidizer 9…Alkaline aqueous solution 10...Atomization chamber 11… Ultrasonic transducer 12...High frequency power supply 13… Supply port 14... Overflow port 15…Supply mechanism 16… Solution tank 17… Solution pump 18…Bottom plate 18A…Opening 19... Lead wire 20... Blower mechanism 21... Air heater 22…Solution warmer 24... Supply Fan 25...Pipe member 26... Element 26A...Right element 26B...Left element 27…Temperature sensor 28… Humidity sensor 29…Supply Fan 30… Electrostatic precipitator 31...discharge electrode 31A...Positive electrode 31B... Negative electrode 32…Dust collection electrode 33…Power supply 34... Switch 35... Air circulation path 41…Sprayer 42...Atomization electrode 42A…Metal ring 43…High-voltage power supply 47…Spray case 50... Spray Unit 51…Discharge protrusion 52...Fine spray holes 53…Capillary tube 54…Nozzle block 54A...Main body 54B...Plate section 54a…Flange 54b... Stepped section 54c...Cylinder part 54d... Male screw 54e…Connection hole 54x…Through hole 55... Gasket 56… Clamping plate 56x...Through hole 57...Water tap socket 58…Connecting bolts 61... Spray Chamber 62... Air Chamber 63... Partition wall 64...Air vent 65... Pump 66…Liquid tank 67... Blower mechanism 70...Cyclone 71...Cylindrical section 72...Tapered section 73...Inflow duct 74…Liquid outlet 75... Exhaust duct 76... Liquid tank 78... Wet scrubber 79… Nozzle 80… Reactor 81…Mixing container 82...Dryer W...Liquid level P…liquid column H…Liquid column surface

Claims

1. The atomization process involves turning an alkaline aqueous solution into a mist using an atomizer, The mist of the alkaline aqueous solution obtained in the atomization step is mixed with the exhaust gas. The carbon dioxide in the exhaust gas is absorbed into the mist. The cations in the mist combine with carbon dioxide to form a carbonate. A mixing step to make the mist contain carbonates, A separation step is performed to separate the mist containing carbonate obtained in the mixing step from the exhaust gas. Includes, In the atomization process, A method for producing carbonates in which the average particle size of an alkaline aqueous solution mist is 50 μm or less.

2. A method for producing a carbonate according to claim 1, In the atomization process, The atomizer uses ultrasonic vibration to convert an alkaline aqueous solution into a mist. A method for producing carbonate, wherein the atomizer vibrates an alkaline aqueous solution ultrasonically and blows exhaust gas onto the surface of a liquid column that protrudes from the liquid surface, thereby mixing the mist with the exhaust gas.

3. A method for producing a carbonate according to claim 1, In the atomization process, The atomizer uses ultrasonic vibration to convert an alkaline aqueous solution into a mist. The atomizer uses ultrasonic vibration to create an alkaline aqueous solution, and blows a conveying gas onto the surface of the liquid column that protrudes from the liquid surface to form a mist mixture. In the mixing step, A method for producing a carbonate by mixing the aforementioned mist mixture gas with exhaust gas.

4. A method for producing a carbonate according to claim 1, In the atomization process, The atomizer electrostatically atomizes the alkaline aqueous solution sprayed from the nozzle into a mist. A method for producing carbonate, comprising blowing exhaust gas onto mist that has been electrostatically atomized by spraying from a nozzle of the atomizer, thereby mixing the mist and the exhaust gas.

5. A method for producing a carbonate according to claim 1, In the atomization process, The atomizer electrostatically atomizes the alkaline aqueous solution sprayed from the nozzle into a mist. The atomizer blows a conveying gas onto the mist that is sprayed from the nozzle and electrostatically atomized to form a mist mixture. In the mixing step, A method for producing carbonate by mixing a mist mixture gas with exhaust gas.

6. A method for producing a carbonate according to any one of claims 1 to 5, In the atomization process, A method for producing carbonates in which the average particle size of an alkaline aqueous solution mist is 30 μm or less.

7. A method for producing a carbonate according to claim 6, In the atomization process, A method for producing carbonates in which the average particle size of an alkaline aqueous solution mist is 100 nm or larger.

8. A method for producing a carbonate according to any one of claims 1 to 7, In the atomization process, Using a caustic soda solution in an alkaline aqueous solution, In the mixing step, The carbon dioxide in the exhaust gas reacts with the caustic soda in the mist to produce a mist containing sodium carbonate. In the separation step, A method for producing carbonates by separating a mist containing sodium carbonate from exhaust gas.

9. A method for producing a carbonate according to claim 8, further, The sodium carbonate solution obtained in the separation step is reacted with calcium hydroxide, A method for producing a carbonate, which includes a reaction step to produce calcium carbonate.

10. A method for producing a carbonate according to claim 9, In the reaction step, By mixing calcium hydroxide with a sodium carbonate solution, the sodium carbonate and calcium hydroxide react to form calcium carbonate. A method for producing a carbonate, comprising a drying step of separating and drying the calcium carbonate precipitate obtained in the reaction step.

11. A method for producing a carbonate according to any one of claims 1 to 10, In the separation step, A method for producing carbonates, which involves separating a carbonate-containing mist from exhaust gas using a cyclone.

12. A method for producing a carbonate according to any one of claims 1 to 11, The alkaline aqueous solution used in the atomization process, A method for producing carbonates using a caustic soda solution generated from seawater.

13. A method for producing a carbonate according to any one of claims 1 to 12, In the mixing step, A method for producing carbonates, comprising mixing an alkaline aqueous solution mist with exhaust gas using a static mixer.

14. A method for producing a carbonate according to any one of claims 1 to 13, In the mixing step, The alkaline aqueous solution mist and exhaust gas are mixed in a mixer, A method for producing carbonate, wherein the temperature inside the mixer is kept below the dew point temperature.

15. A method for producing a carbonate according to any one of claims 1 to 14, further, This includes a pretreatment step to separate air pollutants contained in exhaust gas, In the aforementioned pretreatment step, A method for producing carbonates using carbon dioxide from exhaust gases, which have had air pollutants separated, as a raw material.

16. A method for producing a carbonate according to any one of claims 1 to 15, further, Includes a pretreatment step to remove particulate matter contained in exhaust gas, In the aforementioned pretreatment step, A method for producing carbonates using carbon dioxide from exhaust gas, which has had particulate matter separated, as a raw material.

17. A method for producing a carbonate according to any one of claims 1 to 7, Alkaline aqueous solution, Aqueous solution containing alkali metals or alkaline earth metals, A method for producing carbonates obtained by dissolving natural products or waste containing alkali metals or alkaline earth metals in water.

18. A method for producing a carbonate according to any one of claims 1 to 17, In the atomization process, A method for producing carbonates by controlling the heating of a gas and an alkaline aqueous solution.

19. A method for producing a carbonate according to any one of claims 1 to 18, In the atomization step and the mixing step, A method for producing carbonates by controlling the flow rate and temperature of a mixture of exhaust gas and mist.

20. A atomizer that atomizes an alkaline aqueous solution into a mist, The mist generated by the atomizer is mixed with the exhaust gas, A mixer that combines the cations of the mist with carbon dioxide to form a carbonate, The mist obtained by the aforementioned mixer is separated from the exhaust gas. A separator for recovering the mist containing carbonates, Equipped with, The atomizer described above, A carbonate production apparatus that produces an alkaline aqueous solution mist with an average particle size of 50 μm or less.

21. A carbonate production apparatus according to claim 20, The atomizer described above, An ultrasonic atomizer that uses ultrasonic vibrations to turn an alkaline aqueous solution into a mist, The aforementioned ultrasonic atomizer, A carbonate production apparatus equipped with a blowing mechanism that mixes mist and exhaust gas by blowing exhaust gas onto the surface of a liquid column that protrudes from the liquid surface by ultrasonic vibration of an alkaline aqueous solution.

22. A carbonate production apparatus according to claim 20, The atomizer described above, An ultrasonic atomizer that uses ultrasonic vibrations to turn an alkaline aqueous solution into a mist, The aforementioned ultrasonic atomizer, It is equipped with a blowing mechanism that uses ultrasonic vibration to vibrate an alkaline aqueous solution, blowing a transport gas onto the surface of a liquid column that protrudes from the liquid surface to create a mist mixture. The aforementioned mixer, A apparatus for producing carbonates, which mixes the aforementioned mist mixture gas with exhaust gas.

23. A carbonate production apparatus according to claim 20, The atomizer described above, An electrostatic atomizer that electrostatically atomizes an alkaline aqueous solution sprayed from a nozzle into a mist, The electrostatic atomizer, A carbonate production apparatus equipped with a blowing mechanism that mixes electrostatically atomized mist with exhaust gas.

24. A carbonate production apparatus according to claim 20, The atomizer described above, An electrostatic atomizer that electrostatically atomizes an alkaline aqueous solution sprayed from a nozzle into a mist, The electrostatic atomizer, It is equipped with a blowing mechanism that blows a transport gas into electrostatically atomized mist to create a mist-mixed gas. The aforementioned mixer, A device for producing carbonates by mixing a mist mixture gas with exhaust gas.

25. A carbonate production apparatus according to any one of claims 20 to 24, The atomizer described above, A carbonate production apparatus that produces an alkaline aqueous solution mist with an average particle size of 30 μm or less.

26. A carbonate production apparatus according to claim 25, The atomizer described above, A carbonate production apparatus that produces an alkaline aqueous solution mist with an average particle size of 100 nm or more.

27. A carbonate production apparatus according to any one of claims 20 to 26, The alkaline aqueous solution that the atomizer produces as mist is a caustic soda solution. The aforementioned mixer, A device for producing carbonates by reacting caustic soda mist with carbon dioxide from exhaust gas to produce sodium carbonate.

28. The apparatus for producing carbonate according to claim 27, further, The sodium carbonate solution obtained in the separator is reacted with calcium hydroxide, A carbonate production apparatus equipped with a reactor for producing calcium carbonate.

29. The apparatus for producing carbonate according to claim 28, further, The reactor is equipped with a dryer for drying the calcium carbonate produced in the reactor, The reactor is, Mix calcium hydroxide with sodium carbonate solution, The system includes a mixing vessel for reacting sodium carbonate with calcium hydroxide to precipitate calcium carbonate, The aforementioned dryer is a carbonate production apparatus that dries the calcium carbonate obtained in the mixing container into a powder.

30. A carbonate production apparatus according to any one of claims 20 to 29, A carbonate production apparatus in which the separator is a cyclone.

31. A carbonate production apparatus according to any one of claims 20 to 30, The alkaline aqueous solution that the atomizer produces as mist is A device for producing carbonates, which are caustic soda solutions produced using seawater as a raw material.

32. A carbonate production apparatus according to any one of claims 20 to 26, The alkaline aqueous solution that the atomizer produces as mist is Aqueous solution containing alkali metals or alkaline earth metals, A apparatus for producing carbonates, which are aqueous solutions obtained by dissolving alkali metals or alkaline earth metals in natural products or waste materials in water.

33. A carbonate production apparatus according to any one of claims 20 to 32, The aforementioned mixer is a static mixer in the carbonate production apparatus.

34. A carbonate production apparatus according to any one of claims 20 to 33, further comprising: SO260 is an air pollutant released from exhaust fumes. ｘ And NO ｘ A carbonate production apparatus equipped with a pre-treatment unit for separating the carbonate.

35. A carbonate production apparatus according to any one of claims 20 to 34, further comprising: A carbonate production apparatus equipped with a pretreatment unit to remove particulate matter contained in exhaust gas.

36. A carbonate production apparatus according to any one of claims 20 to 35, Furthermore, it is equipped with a controller that controls the temperature of the gas and the alkaline aqueous solution. The atomizer described above is A gas heater for heating gases, It has a solution warmer for heating alkaline aqueous solutions, A carbonate production apparatus in which the controller controls the gas heater and the solution heater.

37. A carbonate production apparatus according to any one of claims 20 to 36, Furthermore, in the atomizer and the mixer, A carbonate production apparatus equipped with a controller that controls the flow rate and temperature of the exhaust gas and mist mixture.

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