System, method, and apparatus for treating carbon dioxide gas

Abstract

This carbon dioxide gas treatment system comprises: a first reaction furnace (20) which accommodates an alkali metal hydroxide, has an exhaust gas inlet for supplying a carbon dioxide gas-containing exhaust gas containing a carbon dioxide gas, and generates an alkali metal carbonate by reacting the alkali metal hydroxide with the carbon dioxide gas in the carbon dioxide gas-containing exhaust gas; an alkali metal carbonate decomposition device (70) which decomposes the alkali metal carbonate generated in the first reaction furnace to generate the alkali metal hydroxide and the carbon dioxide gas; and a combustible gas generation device (100) which generates a combustible gas using the carbon dioxide gas generated in the alkali metal carbonate decomposition device. The alkali metal hydroxide generated in the alkali metal carbonate decomposition device (70) is circulated to the first reaction furnace (20).

Description

Carbon Dioxide Treatment System, Treatment Method, and Treatment Apparatus

[0001] The present invention relates to a carbon dioxide treatment system, treatment method, and treatment apparatus for effectively reducing carbon dioxide while generating useful substances using reaction materials.

[0002] One of the causes of global warming is the emission of carbon dioxide, which is a greenhouse gas. Various methods are known as recovery techniques for collecting carbon dioxide from the atmosphere. The inventor of the present invention has proposed a method for treating carbon dioxide that reforms the recovered carbon dioxide into useful substances (Patent Document 1).

[0003] According to Patent Document 1, while storing sodium hydroxide (NaOH) in a heated stainless steel reactor and supplying carbon dioxide (CO ２ ), carbon dioxide (CO ２ is reduced, and hydrogen (H ２ ) can be generated as a useful substance. [[ID=十六]] [[ID=十七]]

[0004] [[ID=十八]]Patent No. 6203523 [[ID=十九]] [[ID=二十]]

[0005] [[ID=二十一]] However, in the case of the technology described in Patent Document 1, there is a problem that the reduction rate of carbon dioxide (CO [[ID=二十二]] ２ [[ID=二十三]]) decreases when the reaction proceeds by a certain amount in the reactor. For practical use, it has been required to further increase the reaction efficiency in the reactor and maintain and improve the reduction rate of carbon dioxide (CO [[ID=二十四]] ２ [[ID=二十五]]). [[ID=二十六]] [[ID=二十七]]

[0006] [[ID=二十八]] Further, the exhaust gas of combustion gas generated in various industrial fields such as internal combustion engines contains a large amount of carbon dioxide (CO [[ID=二十九]] ２ [[ID=三十]]). While efficiently reducing the carbon dioxide (CO [[ID=三十一]] ２ [[ID=三十二]]) in this exhaust gas in an energy-saving and low-cost manner, it is required to stably and safely generate combustible gases such as hydrogen (H [[ID=三十三]] ２ [[ID=三十四]]), which are useful substances. [[ID=三十五]] [[ID=三十六]]

[0007] [[ID=三十七]] The present invention has been made in view of the above problems, and while efficiently reducing carbon dioxide (CO [[ID=三十八]] ２ [[ID=三十九]]) in carbon dioxide-containing exhaust gas in an energy-saving and low-cost manner, hydrogen (H [[ID=四十]] ２ ), which is a useful substance,The objective is to provide a carbon dioxide treatment system, treatment method, and treatment apparatus capable of stably and safely generating combustible gases such as )

[0008] To solve the above problems, the carbon dioxide treatment system of the present invention comprises a first exhaust gas inlet that contains alkali metal hydroxides including alkali metals and supplies carbon dioxide-containing exhaust gas, a first reactor that reacts the alkali metal hydroxides with the carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates including alkali metals, an alkali metal carbonate decomposition device that decomposes the alkali metal carbonates produced in the first reactor to produce alkali metal hydroxides and carbon dioxide, and a combustible gas generation device that uses the carbon dioxide produced in the alkali metal carbonate decomposition device to produce combustible gas, and is characterized in that the alkali metal hydroxides produced in the alkali metal carbonate decomposition device are circulated back to the first reactor.

[0009] Furthermore, the carbon dioxide treatment system of the present invention comprises: a first reactor that contains alkali metal hydroxides containing alkali metals and is equipped with a first exhaust gas inlet for supplying carbon dioxide-containing exhaust gas containing carbon dioxide, and reacts the alkali metal hydroxides with carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates containing alkali metals; a second reactor that contains the alkali metal carbonates produced in the first reactor and is equipped with a second exhaust gas inlet for supplying carbon dioxide-containing exhaust gas containing carbon dioxide, and reacts the alkali metal carbonates with carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal bicarbonates (baking soda) containing alkali metals; a third reactor that decomposes the alkali metal bicarbonates produced in the second reactor to produce alkali metal carbonates and carbon dioxide; an alkali metal carbonate decomposition device that decomposes the alkali metal carbonates produced in the third reactor to produce alkali metal hydroxides; and a combustible gas generation device that uses the carbon dioxide produced in the third reactor to produce combustible gas, wherein the alkali metal hydroxides produced in the alkali metal carbonate decomposition device are circulated back to the first reactor.

[0010] The present invention provides a method for treating carbon dioxide, comprising: a first reaction step of reacting an alkali metal hydroxide with carbon dioxide in a carbon dioxide-containing exhaust gas to produce an alkali metal carbonate; an alkali metal carbonate decomposition step of decomposing the alkali metal carbonate produced in the first reaction step to produce an alkali metal hydroxide and carbon dioxide; a combustible gas production step of producing a combustible gas using the carbon dioxide produced in the alkali metal carbonate decomposition step; and a method for treating alkali metal hydroxide produced in the alkali metal carbonate decomposition step of circulating the alkali metal hydroxide back to the first reaction step.

[0011] Furthermore, the carbon dioxide treatment method of the present invention is characterized by comprising: a first reaction step of reacting alkali metal hydroxide with carbon dioxide in carbon dioxide-containing exhaust gas to produce alkali metal carbonate; a second reaction step of reacting the alkali metal carbonate produced in the first reaction step with carbon dioxide in carbon dioxide-containing exhaust gas to produce alkali metal bicarbonate (baking soda); a third reaction step of decomposing the alkali metal bicarbonate produced in the second reaction step to produce alkali metal carbonate and carbon dioxide; an alkali metal carbonate decomposition step of decomposing the alkali metal carbonate produced in the third reaction step to produce alkali metal hydroxide; a combustible gas production step of producing combustible gas using the carbon dioxide produced in the third reaction step; and circulating the alkali metal hydroxide produced in the alkali metal carbonate decomposition step back to the first reaction step.

[0012] The carbon dioxide processing apparatus of the present invention is characterized by comprising: a sealed reaction furnace having a carbon dioxide inlet for supplying carbon dioxide gas and a treatment gas outlet for discharging a treatment gas containing combustible gas after treatment; a heating unit for raising the ambient temperature inside the reaction furnace to a predetermined temperature or higher; and a reaction material tray provided inside the reaction furnace, on which a first reaction material made of alkali metal hydroxide and a second reaction material made of at least aluminum or zinc are placed.

[0013] According to the carbon dioxide treatment system, treatment method, and treatment apparatus of the present invention, carbon dioxide (CO2) in carbon dioxide-containing exhaust gas is processed. ２) is being reduced efficiently in an energy-saving and low-cost manner, while also utilizing the useful substance hydrogen (H ２ It is possible to continuously generate flammable gases such as ) in a stable and safe manner.

[0014] This is a diagram showing a carbon dioxide treatment system according to the first embodiment of the present invention. This is a diagram showing the first reactor. This is a diagram showing a bipolar membrane electrodialysis apparatus as an alkali metal carbonate decomposition apparatus. This is a diagram showing a carbon dioxide treatment apparatus according to the present invention, and is a diagram showing a combustible gas generation reactor as a combustible gas generation apparatus. This is a diagram showing a combustible gas generation reactor according to the first modified example. This is a diagram showing a combustible gas generation reactor according to the second modified example. This is a diagram showing a combustible gas generation reactor according to the third modified example. This is a diagram showing a combustible gas generation reactor according to the fourth modified example. This is a diagram showing a carbon dioxide treatment system according to the second embodiment of the present invention. This is a diagram showing an electric field apparatus as a combustible gas generation apparatus. This is a diagram showing a carbon dioxide treatment system according to the third embodiment of the present invention. This is a diagram showing the second reactor. This is a diagram showing the third reactor. This is a diagram showing the fourth reactor as an alkali metal carbonate decomposition apparatus. This is a diagram showing a carbon dioxide treatment system according to the fourth embodiment of the present invention.

[0015] [First Embodiment] Figure 1 shows a carbon dioxide treatment system 1 according to the first embodiment of the present invention. As shown in Figure 1, the carbon dioxide treatment system 1 according to the first embodiment of the present invention mainly comprises a first reactor 20 that contains alkali metal hydroxides and supplies carbon dioxide-containing exhaust gas containing carbon dioxide to react alkali metal hydroxides with carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates; a bipolar membrane electrodialysis (BMED) (alkali metal carbonate decomposition apparatus) 70 that decomposes the alkali metal carbonates produced in the first reactor 20 to produce alkali metal hydroxides and carbon dioxide; and a combustible gas generation reactor (combustible gas generation apparatus) 100 as a carbon dioxide treatment apparatus of the present invention that generates combustible gas using the carbon dioxide produced in the bipolar membrane electrodialysis apparatus 70. In addition, an exhaust gas pretreatment apparatus 10 is provided to pretreatment the carbon dioxide-containing exhaust gas supplied to the first reactor 20.

[0016] The exhaust gas pretreatment device 10 primarily treats carbon dioxide (CO2) emitted as industrial waste. ２ This device adjusts exhaust gas containing carbon dioxide (CO2), and consists of a water seal cleaner 12, a demister 14, and a gas cooler 16. ２ ) contains about 20%, and in addition to carbon dioxide, it also contains, for example, nitrogen (N ２ ) and oxygen (O ２ Approximately 80% of the exhaust gas is contained in the water seal cleaner 12, which first performs rough cleaning, extinguishing, and humidification of the exhaust gas. The demister 14 removes mist from the exhaust gas, and the gas cooler 16 cools the exhaust gas to a temperature range of, for example, 30°C to 55°C.

[0017] Referring to Figure 2, the first reactor 20 is shown. As shown in Figure 2, the first reactor 20 consists mainly of a reactor body 21 which is a cylindrical casing. The furnace perimeter wall of the reactor body 21 contains alkali metal hydroxides as reactants, such as sodium hydroxide (NaOH) and water (H ２ An inlet 22 for introducing O) is provided, and an exhaust gas inlet pipe (first exhaust gas inlet) 23 is provided, which is connected to the pretreatment device 10 via an on / off valve 23a that can open and close the internal passage to open and close it, and a hose, etc., and supplies exhaust gas containing carbon dioxide that has been pretreated in the pretreatment device 10.

[0018] Furthermore, alkali metal carbonates, such as sodium carbonate (Na), generated from within the reactor body 21 are also present in the reactor body 21. ２ CO ３ A sodium carbonate outlet 24 is provided for extracting the sodium carbonate, and a gas component outlet 25 is provided for discharging the remaining gas component of the carbon dioxide-containing exhaust gas after the carbon dioxide has been used.

[0019] The inlet 22 consists of a sodium hydroxide inlet 22a and a water inlet 22b. The sodium hydroxide inlet 22a is connected to a sodium hydroxide storage tank 27 via a sodium hydroxide supply control device 26 that controls the supply of sodium hydroxide, and the water inlet 22b is connected to a water tank 29 via a water control device 28 that controls the supply of water. The sodium hydroxide supply control device 26 and the water control device 28 are connected to a control device (not shown; hereinafter simply referred to as the control device) that manages the carbon dioxide treatment system 1, and the amount and timing of supply of sodium hydroxide and water to the first reactor 20 are appropriately adjusted by the sodium hydroxide supply control device 26 and the water control device 28. As a result, sodium hydroxide is contained in the first reactor 20 in the form of an aqueous solution.

[0020] The sodium carbonate outlet 24 is connected to the bipolar membrane electrodialysis machine 70 via an on / off valve 24a, which allows for opening and closing of the internal passage by operation, a hose, etc., and sodium carbonate (Na) is generated by, for example, opening and closing the on / off valve 24a by a control device. ２ CO ３ (aq)) is supplied to the bipolar membrane electrodialysis machine 70.

[0021] A scavenging device 30 is provided at the gas component outlet 25, and by operating the scavenging device 30 by a control device, for example, the remaining residual gas components (N) of the carbon dioxide-containing exhaust gas other than the carbon dioxide used in the reaction are removed. ２ It is possible to discharge (etc.) to the outside.

[0022] The reactor body 21 is constructed of, for example, steel. Stainless steel is preferred, such as austenitic SUS303, SUS304, SUS316, or ferritic SUS430. The inner surface of the furnace perimeter wall of the reactor body 21 is coated with an alkali-resistant coating or glass lining to cover the perimeter wall. Alternatively, the reactor body 21 may be made of a resin such as vinyl ester-based FRP.

[0023] A heating and warming device (first heating and warming section) 32 is installed inside the first reactor 20. For example, an electric heater is used as the heating and warming device 32. The electric heater's temperature can be controlled by a temperature controller (not shown) located outside the first reactor 20. A thermometer (not shown), such as a thermocouple, is installed inside the first reactor 20, and this temperature controller is also connected to a control device, for example. This allows the ambient temperature inside the first reactor 20 to be constantly measured by the thermometer, and the ambient temperature inside the first reactor 20 to be adjusted and maintained within a first specified temperature range (0°C to 60°C).

[0024] Exhaust gas containing carbon dioxide, which has been pretreated by the exhaust gas pretreatment device 10, is supplied from the exhaust gas inlet pipe 23. A microbubble generator (first microbubble generator) 34 is provided in the exhaust gas inlet pipe 23, and the exhaust gas is supplied to the sodium hydroxide aqueous solution as microbubbles. In addition, a stirring device (first stirring device) 36 for stirring the aqueous solution is also provided in the first reactor 20, thereby stirring the sodium hydroxide aqueous solution and mixing sodium hydroxide (NaOH) with carbon dioxide (CO2) in the exhaust gas. ２ This promotes the reaction.

[0025] The bipolar membrane electrodialysis apparatus 70 uses alkali metal carbonates produced in the first reactor 20, such as sodium carbonate (Na ２ CO ３ (aq) From sodium hydroxide (NaOH) and carbon dioxide (CO2) ２ It is a device that generates ).

[0026] Referring to Figure 3, a bipolar membrane electrodialysis (BMED) apparatus 70 is shown. As shown in Figure 3, a known bipolar membrane electrodialysis apparatus 70 is used, and a detailed explanation is omitted here, but the apparatus body 72 has a positive electrode and a negative electrode and electrically processes sodium carbonate (Na ２ CO ３ (aq)) contains the alkaline components sodium hydroxide (NaOH) and carbon dioxide (CO2). ２ It is configured to be disassembled into the following parts. The bipolar membrane electrodialysis apparatus 70 is also connected to a control device and is controlled by the control device.

[0027] The bipolar membrane electrodialysis apparatus 72 receives sodium carbonate (Na) from the first reactor 20. ２ CO ３ A sodium carbonate inlet 74 is provided to supply (aq), and a sodium hydroxide outlet 75 is provided to discharge sodium hydroxide (NaOH) and carbon dioxide (CO2). ２ A carbon dioxide outlet 76 is provided for discharging sodium hydroxide. The sodium carbonate inlet 74 is connected to the first reactor 20, the sodium hydroxide outlet 75 is connected to the sodium hydroxide storage tank 27, and the carbon dioxide outlet 76 is connected to the combustible gas generating reactor 100. The sodium hydroxide outlet 75 is provided with an on / off valve 75a that can open and close to open and close the internal passage, and the on / off valve 75a is also opened and closed as appropriate by the control device.

[0028] As a result, in the bipolar membrane electrodialysis apparatus 70, sodium carbonate (Na) produced in the first reactor 20 is used. ２ CO ３ (aq) From sodium hydroxide (NaOH) and carbon dioxide (CO2) ２ ) is generated in this way. Carbon dioxide (CO) generated in the bipolar membrane electrodialysis apparatus 70 ２ ) is high-purity carbon dioxide (CO2) that does not contain other gaseous components in the exhaust gas. ２ : Approximately 100%). The combustible gas generation reactor 100 generates carbon dioxide (CO2) produced in the bipolar membrane electrodialysis apparatus 70. ２ Using approximately 100%), for example, hydrogen (H ２ It is configured to generate flammable gases such as ).

[0029] Here, a bipolar membrane electrodialysis apparatus (BMED) 70 is used as the alkali metal carbonate decomposition apparatus, but alkali metal carbonates produced in the first reactor 20, such as sodium carbonate (Na), are used. ２ CO ３ ) from which sodium hydroxide (NaOH) and carbon dioxide (CO2) are produced. ２ This is not limited to any device capable of generating ).

[0030] Referring to Figure 4, an example of a combustible gas generation reactor 100 is shown. As shown in Figure 4, the combustible gas generation reactor 100 is configured to be sealed by a reactor body 102 which mainly consists of a cylindrical casing and a lid member 103 which closes one open end of the reactor body 102. The lid member 103 is fastened to the reactor body 102 by fastening members such as bolts.

[0031] The reactor body 102 and the lid member 103 are formed from, for example, steel. Preferably, at least the reactor body 102 is made of stainless steel, such as austenitic SUS303, SUS304, SUS316, or ferritic SUS430.

[0032] On the inner surface of the furnace perimeter wall 104 of the reactor body 102, a highly heat-resistant carbon body 105, mainly composed of carbon (C), is held so as to cover the furnace perimeter wall 104. The shape of the carbon body 105 is preferably cylindrical so as to conform to the reactor body 102, but any cylindrical shape, such as octagonal or dodecagonal, is acceptable as long as it conforms to the reactor body 102.

[0033] A heating section (fifth heating and heat retention section) 106 is provided inside the reactor 100, and the atmosphere inside the reactor 100 is heated, raised, and maintained by the heating section 106. For example, an electric heater is used as the heating section 106, and the electric heater is located at the bottom inside the reactor 100 and extends in the longitudinal direction of the reactor body 102. The electric heater's temperature can be controlled by a temperature controller (not shown) provided outside the reactor 100 and connected to a control device, allowing the ambient temperature inside the reactor 100 to be adjusted between approximately 50°C and 600°C. A thermometer (not shown), such as a thermocouple, is provided inside the reactor 100 to constantly measure the ambient temperature inside the reactor 100, and the ambient temperature inside the reactor 100 can be adjusted by the temperature controller according to the measurement value of the thermometer.

[0034] Furthermore, within the reactor 100, a reactant tray 112 is provided, for example, located directly above the heating section 106 and extending in the longitudinal direction of the reactor body 102. The reactant tray 112 contains the first reactant 130 and the second reactant 132.

[0035] The first reactant 130 may preferably be a highly reactive alkali metal hydroxide, but mainly alkali metal hydroxides such as sodium hydroxide (NaOH) and potassium hydroxide (KOH), or mixtures thereof, are used. Preferably, the first reactant 130 is a solid and in granular form.

[0036] The second reactant 132 is at least aluminum (Al), zinc (Zn), or a mixture thereof. Specifically, to improve the reaction efficiency as described later, the aluminum (Al) and zinc (Zn) are preferably composed of multiple small pieces of thin aluminum (Al) and zinc (Zn), or multiple pellet-like particles obtained by compressing aluminum (Al) and zinc (Zn).

[0037] Furthermore, as will be described later, it is also effective to add stainless steel materials such as SUS304 (18% Cr - 8% Ni - remainder Fe) and SUS316 (18% Cr - 2.5% Ni - 1% or less Mo - remainder Fe), which contain austenitic Ni, in the form of multiple small pieces or multiple pellet-shaped particles.

[0038] The reaction material tray 112 may be made of a metal such as steel, but the reaction material tray 112 itself may also be made of stainless steel such as SUS304 or SUS316 containing aluminum (Al), zinc (Zn), or austenitic Ni.

[0039] On the furnace periphery wall 104 of the reactor body 102, for example, carbon dioxide (CO) is located at one end. ２ A carbon dioxide inlet pipe 107 is installed vertically as a carbon dioxide inlet to supply carbon dioxide into the reactor 100, and a process gas outlet pipe 108 is installed vertically as a process gas outlet, located at the other end, for example, to discharge the process gas to the outside.

[0040] The carbon dioxide inlet pipe 107 is connected to the carbon dioxide outlet 76 of the bipolar membrane electrodialysis apparatus 70 via a hose or the like. The processed gas outlet pipe 108 is connected to, for example, a processed gas storage tank (not shown) via a hose or the like. The carbon dioxide inlet pipe 107 and the processed gas outlet pipe 108 are each provided with on / off valves 107a and 108a, respectively, which can be opened and closed to open and close the internal passages. These on / off valves 107a and 108a are also opened and closed as appropriate by the control device.

[0041] The processing gas outlet pipe 108 is equipped with a processing gas sensor 114 so that, for example, the components of the processing gas can be measured. As described later, the processing gas sensor 114 is hydrogen (H), which is a substance useful as a processing gas. ２ Since ) is discharged, a hydrogen sensor capable of measuring hydrogen concentration can be considered. In addition, a vacuum pipe 109 is provided branching off from the processed gas outlet pipe 108, and the vacuum pipe 109 is connected to a vacuum pump (not shown). An on / off valve 109a is also provided on the vacuum pipe 109. The on / off valve 109a is also opened and closed as appropriate by the control device.

[0042] Furthermore, the furnace peripheral wall 104 of the reactor body 102 is located near the bottom of the reactor 100 and contains water (H ２ A drain pipe 115 is provided for discharging O), and an on / off valve 115a is provided on the drain pipe 115. The operation of the carbon dioxide treatment system according to the first embodiment configured in this way, that is, the method of treating carbon dioxide, will be described below.

[0043] [Function of pretreatment device 10] The waste is mainly discharged as industrial waste and contains carbon dioxide (CO2). ２ Carbon dioxide-containing exhaust gas (containing approximately 20%) is supplied to the exhaust gas pretreatment device 10. In the exhaust gas pretreatment device 10, the exhaust gas is roughly washed, extinguished, and humidified in the water seal cleaner 12, mist is removed from the exhaust gas in the demister 14, and the temperature of the exhaust gas is cooled in the gas cooler 16 to a range of, for example, 30°C to 55°C. The carbon dioxide-containing exhaust gas that has been pretreated in this way is then supplied to the first reactor 20 via the exhaust gas inlet pipe 23.

[0044] [Operation of the First Reactor 20] (First Reaction Process) Granular sodium hydroxide (NaOH) is supplied to the first reactor 20 from the sodium hydroxide storage tank 27 via the sodium hydroxide supply control device 26, and water (H) is supplied from the water tank 29 via the water control device 28. ２ O) is supplied, and the on / off valve 23a is opened, allowing carbon dioxide (CO) to enter from the exhaust gas pretreatment device 10 via the exhaust gas inlet pipe 23. ２ Carbon dioxide-containing exhaust gas (approximately 20%) is supplied. Then, the heating and heat retention device 32 adjusts the ambient temperature inside the first reactor 20 to a first specified temperature range (0°C to 60°C).

[0045] For more details, the first reactor 20 contains sodium hydroxide (NaOH) and water (H ２ O) is supplied so that the aqueous solution of sodium hydroxide (NaOH) reaches a predetermined concentration (for example, 20-30% by mass), and the aqueous solution of sodium hydroxide (NaOH) is contained within this aqueous solution of sodium hydroxide (NaOH). ２ Exhaust gas containing carbon dioxide (approximately 20%) is supplied as microbubbles by the microbubble generator 34.

[0046] As a result, the following reaction occurs in the first reactor 20 within the first specified temperature range (0°C to 60°C), producing sodium carbonate (Na ２ CO ３ ) and water (H ２ O) and CO are produced. 2NaOH + CO ２ →Na ２ CO ３ +H ２ O ... (1)

[0047] As a result, the above reaction in the first reactor 20 proceeds slowly within the first specified temperature range (0°C to 60°C), and sodium carbonate (Na) ２ CO ３ Although it takes time to produce the carbon dioxide, the ambient temperature inside the first reactor 20 can basically remain at room temperature, so heating by the heating and warming device 32 is hardly necessary, making it possible to configure the carbon dioxide treatment system as a whole in an energy-saving and safe manner.

[0048] In this way, sodium carbonate (Na) is placed in the first reactor 20. ２ CO ３ When this sodium carbonate (Na) is produced, ２ CO ３ By opening the opening / closing member 24a, the sodium carbonate is supplied to the bipolar membrane electrodialysis machine 70 from the sodium carbonate inlet 64 via the sodium carbonate outlet 24.

[0049] [Operation of the Bipolar Membrane Electrodialysis Machine (BMED) 70] (Alkali Metal Carbonate Decomposition Process) In the bipolar membrane electrodialysis machine 70, sodium carbonate (Na) is decomposed within the bipolar membrane electrodialysis machine body 72. ２ CO ３ (aq)) is electrically alkaline, consisting of sodium hydroxide (NaOH) and carbon dioxide (CO2). ２ ) is decomposed into. The generated sodium hydroxide (NaOH) is discharged through the sodium hydroxide outlet 75 by opening the on / off valve 75a, returned to the sodium hydroxide storage tank 27, and circulated to the first reactor 20. Meanwhile, high-purity carbon dioxide (CO) that does not contain other gas components in the exhaust gas is used. ２ Approximately 100% of the carbon dioxide is discharged through the carbon dioxide outlet 76 and supplied to the combustible gas generation reactor 100.

[0050] [Operation of the Combustible Gas Generation Reactor 100] (Combustible Gas Generation Process) In the combustible gas generation reactor 100 as a carbon dioxide processing apparatus of the present invention, first, the lid member 103 is opened, and a reaction material tray 112 is placed inside the reactor 100, on which a first reaction material 130 made of, for example, granular sodium hydroxide (NaOH), and a second reaction material 132 made of, for example, multiple small pieces or multiple pellet-shaped particles of aluminum (Al) are placed. Then the lid member 103 is closed, and the on / off valves 107a, 108a, 109a, and 115a are closed to seal the reactor 100.

[0051] Then, in order to remove unwanted gases from the atmosphere inside the reactor 100, the on / off valve 109a is opened to create a vacuum and the inside of the reactor 100 is evacuated. Furthermore, the on / off valves 107a and 108a are opened to release carbon dioxide (CO2). ２If you supply ) the unwanted gas will be discharged through the processing gas outlet pipe 108, so vacuuming is not necessarily required, but by vacuuming, carbon dioxide (CO) will be released early ２ ) can be reduced.

[0052] Then, once the reactor 100 is under vacuum, the on / off valve 109a is closed, while the heating unit 106 begins heating the atmosphere inside the reactor 100, and the on / off valve 107a is opened to release carbon dioxide (CO2). ２ The supply of ) is started. For example, when the ambient temperature inside the reactor 100 reaches 100°C or higher, the on / off valve 108a is also opened and the discharge of the process gas from the process gas outlet pipe 108 is started.

[0053] Carbon dioxide (CO) is released into the reactor 100. ２ When the ) is filled, carbon dioxide (CO) is initially released from the processed gas outlet pipe 108. ２ Although ) is emitted, hydrogen (H) gradually becomes the process gas. ２ ) begins to be discharged.

[0054] Furthermore, the heating section 106 is adjusted to raise the ambient temperature inside the reactor 100, and when the ambient temperature exceeds approximately 240°C, carbon dioxide (CO2) is released. ２ Significant progress has been made in reducing ) and hydrogen (H) is used as the processing gas. ２ Emissions of ) will increase.

[0055] The following describes the carbon dioxide (CO2) discharged from the treatment gas outlet pipe 108 in a reaction material tray 112 when a first reaction material 130 consisting of granular sodium hydroxide (NaOH) and a second reaction material 132 consisting of multiple pellet-shaped aluminum (Al) particles are placed on the reaction material tray 112, according to the ambient temperature inside the reaction furnace 100. ２ ) component ratio, hydrogen (H ２ The relationship between the component ratios of ) and the results of mass spectrometry measurements is shown in Table 1. [Table 1]

[0056] In this way, as the ambient temperature of the reactor 100 rises, carbon dioxide (CO2) is released. ２ ) reduction is progressing, hydrogen (H ２), the production amount increases. Especially when the ambient temperature of the reactor 100 is 100°C or higher, significant reduction of carbon dioxide (CO ２ ) is confirmed to progress significantly, and around 100°C or higher is considered to be the starting temperature of substantial reduction of carbon dioxide (CO ２ ). Around 100°C, it is considered that water vapor such as H ２ O, which is generated by the reaction described later and not used in other reactions, is also discharged from the processing gas outlet pipe 108.

[0057] Comparing with the data disclosed in Patent Document 1 (Patent No. 6203523) as the above background art, it can be understood that the degree of reduction of carbon dioxide (CO ２ ) is improved when the ambient temperature of the reactor 100 is 240°C (predetermined temperature) or higher.

[0058] Regarding this, it can be considered as follows. The main reaction inside the reactor 100 is considered as follows. 2NaOH + CO ２ →Na ２ CO ３ + H ２ O... (2) 2NaOH + 2Al + 6H ２ O → 2Na(Al(OH) ４ ) + 3H ２ That is, by placing the second reaction material 132 made of aluminum (Al) together with the first reaction material 130 made of sodium hydroxide (NaOH) in the reactor 100, the first reaction material 130 reacts with aluminum (Al) under the presence of H ２ O generated by the above reaction formula (2), and it is considered that hydrogen (H ２ ) is generated.

[0059] Here, the case where the second reaction material 132 is aluminum (Al) is exemplified. When the second reaction material 132 is zinc (Zn), the main reaction inside the reactor 100 is considered as follows. 2NaOH + Zn + 2H ２ O → Na ２ (Zn(OH) ４ ) + H ２ ... (4)

[0060] Further, under high-temperature conditions, a reduction reaction with zinc (Zn) proceeds in the presence of carbon dioxide (CO ２ ), and water (H ２ O), and hydrocarbons such as methane may be generated as by-products in addition to hydrogen (H ２ ). That is, when the second reaction material 132 made of zinc (Zn) is placed in the reactor 100, two reactions are considered to occur and hydrogen (H ２ ) is generated.

[0061] When the second reaction material 132 is zinc (Zn), as shown in the above reaction formula (4), methane gas (CH ４ ) is generated at the same time. Therefore, the processed gas discharged from the processed gas outlet pipe 108 contains methane gas (CH ２ ) in addition to hydrogen (H ４ ). In this case, a device for separating the discharged hydrogen (H ２ ) and methane gas (CH ４ ) may be used to separately recover hydrogen (H ２ ) and methane gas (CH ４ ).

[0062] When a stainless steel material is used as the second reaction material 132, the stainless steel material mainly acts as a catalyst and is considered to promote the reaction between sodium hydroxide (NaOH), which is an alkali metal hydroxide, and water (H ２ O). Note that the stainless steel material does not necessarily function as a consumable reactant.

[0063] At this time, since the reaction material tray 112 is located directly above the heating unit 6, sodium hydroxide (NaOH), which is the first reaction material 130, aluminum (Al), zinc (Zn), and the above stainless steel material, which are the second reaction material 132, are heated and heated up well, and the above reactions are promoted.

[0064] Furthermore, in the embodiment of the present invention, by holding a highly heat-resistant carbon body 105 on the inner surface of the furnace perimeter wall 104 of the reactor body 102, corrosion of the inner surface of the furnace perimeter wall 104 of the reactor body 102, which is made of steel, due to contact with the molten first reactant 130, which is made of alkali metal hydroxide such as sodium hydroxide (NaOH), is prevented for a long period of time by the carbon body 105.

[0065] Thus, according to the combustible gas generating reactor 100 as a carbon dioxide processing apparatus according to the present invention, even if the ambient temperature of the reactor 100 is relatively low, such as above 100°C and around 240°C, carbon dioxide (CO) can be produced. ２ ) is reduced effectively, and hydrogen (H ２ This results in good production of carbon dioxide (CO2). ２ To maintain and improve the reduction rate of hydrogen (H), a useful substance, efficiently ２ It is possible to continuously generate ).

[0066] As shown in Table 1 above, according to the configuration of the present invention, even if the ambient temperature of the reactor 100 is 360°C or 450°C, carbon dioxide (CO2) is still present. ２ The degree of reduction in carbon dioxide (CO2) is almost the same as at 240°C. Therefore, the energy required to raise the ambient temperature of the reactor 100 by the heating unit 106 can be reduced, resulting in energy savings while reducing carbon dioxide (CO2) emissions. ２ To maintain and improve the reduction rate of hydrogen (H), a useful substance, efficiently ２ It can continue to generate ).

[0067] For example, since the melting point of alkali metal hydroxides is generally in the range of 300 to 350°C, by setting the ambient temperature of the reactor 100 to the range of 300 to 350°C, the first reactant 130 such as sodium hydroxide (NaOH) can be kept in a liquid molten salt state, thereby increasing its reactivity within the reactor 100, and it is thought that an energy-saving and efficient carbon dioxide treatment device can be realized.

[0068] The hydrogen produced in the reactor 100 is mainly molecular hydrogen (H ２It exists as ) and is discharged from the processing gas outlet pipe 108. Even in a high-temperature environment, hydrogen exists in a stable molecular state, so safety inside the reactor can be ensured by properly implementing safety management.

[0069] Referring to Figures 5 to 8, combustible gas generating apparatus, combustible gas generating reactors 200 to 500 according to the first to fourth modifications of the combustible gas generating reactor 100 as a carbon dioxide processing apparatus of the present invention, are shown. [First Modification of the First Embodiment]

[0070] Figure 5 shows a combustible gas generation reactor 200 when molten liquid sodium hydroxide is injected according to the first modified example. Parts common to the combustible gas generation reactor 100 of the first embodiment are denoted by the same reference numerals and their descriptions are omitted, while parts that differ from the combustible gas generation reactor 100 will be described.

[0071] Multiple (for example, four) first reactant injection nozzles (injection nozzles) 110 are arranged in a line along the longitudinal direction of the reactor body 2, located at the top of the furnace perimeter wall 104 of the reactor body 102. The first reactant injection nozzles 110 are devices for injecting a first reactant 130', which consists of liquid sodium hydroxide (NaOH), into the reactor 100, and each is connected to a first reactant tank 122, which stores the liquid first reactant 130', via a first reactant pump 124. Sodium hydroxide (NaOH) is supplied to the first reactant tank 122 from a sodium hydroxide storage tank 27. The first reactant injection nozzles 110 are located outside the reactor 200, and the amount of first reactant 130' injected can be adjusted by an injection control device (not shown) connected to a control device.

[0072] As described above, the melting point of alkali metal hydroxides is generally in the range of 300 to 350°C. In the first modified example, for example, sodium hydroxide (NaOH) is heated above its melting point in the melting heater 123, liquefied, and stored as a molten salt in the first reactant tank 122. This liquid sodium hydroxide (NaOH) is pumped by the first reactant pumping pump 124 and injected in a mist form into the reactor 200 from the first reactant injection nozzle 110.

[0073] In the combustible gas generating reactor 200 according to the first modified example configured in this way, the heating unit 106 starts heating and raising the ambient temperature inside the reactor 200, just as in the first embodiment, and the on / off valve 107a is opened to release carbon dioxide (CO2). ２ After the supply of the first reactant is started, for example, when the ambient temperature inside the reactor 200 reaches 100°C or higher, the injection of the first reactant 130', for example sodium hydroxide (NaOH), into the reactor 200 is started from the first reactant injection nozzle 110, and the on / off valve 108a is opened to start discharging the process gas from the process gas outlet pipe 108.

[0074] Thus, in the first modified example, the first reactant 130', which consists of liquid sodium hydroxide (NaOH), is sprayed into the reactor 200 in a mist-like manner from the first reactant spray nozzle 110. This increases the opportunities for the sodium hydroxide (NaOH) to come into contact with the second reactant 132, and it is believed that the above-mentioned reactions between sodium hydroxide (NaOH) and the second reactant 132 are greatly accelerated.

[0075] For example, similar to the combustible gas generating reactor 100, by setting the ambient temperature of the reactor 200 to a range of 300 to 350°C, matching the melting point of alkali metal hydroxides, it is possible to maintain the liquid sodium hydroxide (NaOH) injected into the reactor 200 from the first reactant injection nozzle 110 in a liquid molten salt state, thereby increasing its diffusivity and reactivity within the reactor 200, and thus realizing an energy-saving and efficient carbon dioxide treatment device.

[0076] [Second Modification of the First Embodiment] Figure 6 shows a combustible gas generating reactor 300 according to the second modification. In this second modification, a first reactant 130'' consisting of granular solid sodium hydroxide (NaOH) is supplied from the first reactant storage 125 to hoppers 126 provided for each first reactant injection nozzle 110', and the first reactant 130'' is injected into the reactor 300 from the first reactant injection nozzle 110' using, for example, a pressurized gas (for example, an inert gas). Sodium hydroxide (NaOH) is supplied to the first reactant storage 125 from a sodium hydroxide storage tank 27.

[0077] In the case of the second modification, although the first reactant 30'' is a solid, it is in the form of fine granules, so it can easily melt while diffusing in the high-temperature reactor 300, producing the same effects as in the second modification described above, while having the advantage that it does not need to be heated in advance to form a molten salt.

[0078] [Third Modification of the First Embodiment] Figure 7 shows a combustible gas generating reactor 400 according to the third modification. In this third modification, similar to the second modification, a first reactant 130'' consisting of granular solid sodium hydroxide (NaOH) is supplied from the first reactant storage 125 to the hopper 126 corresponding to the first reactant injection nozzle 110'', and the first reactant 130'' is injected into the reactor 400 from the first reactant injection nozzle 110'' using pressurized gas (for example, an inert gas), but at the same time carbon dioxide (CO2) is also added. ２ ) is also injected into the reactor 400 from the first reactant injection nozzle 110″. In this case, carbon dioxide (CO) ２ ) may also be used as a pressurized gas.

[0079] In other words, in the third variation, carbon dioxide (CO) ２ ) is injected into the reactor 400 not only from the carbon dioxide inlet pipe 107 but also separately from the first reactant injection nozzle 110″ along with fine granular first reactant 130″. In the third modified example, fine granular first reactant 130″ and carbon dioxide (CO ２ ) increases contact with carbon dioxide (CO ２ This can improve the reduction rate of )

[0080] [Fourth Modification of the First Embodiment] Figure 8 shows a combustible gas generating reactor 500 according to the fourth modification. In this fourth modification, the first modification described above will be used as an example, but in the configuration of each of the above modifications, a stirring device 140 is provided inside the reactor 500.

[0081] The stirring device 140 consists of an electric motor-driven screw blade, for example, mounted directly above the reactant tray 112 and extending in the longitudinal direction of the reactor body 102, and stirs the atmosphere inside the reactor 500 by rotating the screw blade. The electric motor portion of the stirring device 140 is housed in a heat-resistant and corrosion-resistant case, for example, to ensure durability.

[0082] By stirring the atmosphere inside the reactor 500 with the stirring device 140, the above reactions can be promoted, and in particular, the reaction between the second reactant 132 such as aluminum (Al) and zinc (Zn) and the first reactants 130, 130', and 130'' consisting of alkali metal hydroxides such as sodium hydroxide (NaOH) produces Na(Al(OH)) on the surface of the second reactant 132. ４ ) [Sodium aluminate] or Na ２ (Zn(OH) ４ ) [Sodium zincate] etc. can be effectively wiped away. This ensures contact between the second reactant 132 and the first reactants 130, 130', 130'', allowing carbon dioxide (CO) to be effectively removed. ２ While improving the reduction rate of ) a useful substance, hydrogen (H ２ It is possible to continuously generate ).

[0083] Thus, in the combustible gas generating reactors 100 to 500 as a carbon dioxide processing apparatus of the present invention, by placing a second reactant 132 such as aluminum (Al) or zinc (Zn) inside the reactor body 102, carbon dioxide (CO) can be produced even when the ambient temperature inside the reactors 100 to 500 is as low as 240°C. ２ The reaction between the first reactants 130, 130', and 130'', which consist of alkali metal hydroxides such as sodium hydroxide (NaOH), produces carbon dioxide (CO2). ２ ) while reducing the H generated by this ２ By utilizing oxygen, the reaction between the first reactants 130, 130', and 130'' and the second reactant 132 such as aluminum (Al) and zinc (Zn) is promoted, and hydrogen (H) is produced. ２ This allows for the efficient generation of )

[0084] Furthermore, in the combustible gas generation reactors 300-500, the first reactant 130', 130'', which consists of alkali metal hydroxides such as sodium hydroxide (NaOH), is injected into the reactors 300-500 from the first reactant injection nozzles 110, 110', 110''. As a result, even when the ambient temperature inside the reactors 300-500 is low, around 240°C, carbon dioxide (CO2) can be produced. ２ The reactivity between the first reactant 130' and 130'', which consists of an alkali metal hydroxide such as sodium hydroxide (NaOH), is increased, and carbon dioxide (CO2) is produced. ２ This will significantly improve the reduction rate of hydrogen (H), a useful substance. ２ It can be made to generate ).

[0085] Furthermore, in the combustible gas generation reactors 100 to 500, by retaining the carbon body 105 on the inner surface of the furnace perimeter wall 104 of the reactor body 102, corrosion of the inner surface of the furnace perimeter wall 104 of the reactor body 102, which is made of steel, due to contact with the molten first reactant 130, 130', 130'' made of alkali metal hydroxide such as sodium hydroxide (NaOH) can be prevented over a long period of time by the carbon body 105.

[0086] Therefore, in the combustible gas generation reactor 100-500 as a carbon dioxide treatment apparatus of the present invention, even when the ambient temperature of the reactor 100-500 is low, such as around 240°C, carbon dioxide (CO) can be produced. ２ ) effectively reduces hydrogen (H) which is a useful substance. ２ It is possible to generate carbon dioxide (CO2) using the heating unit 106, which reduces the energy required to raise the ambient temperature of the reactor 100-500, thus saving energy while generating carbon dioxide (CO2). ２ To maintain and improve the reduction rate of hydrogen (H), a useful substance, efficiently ２ ) can be produced stably and safely.

[0087] Therefore, although maintenance work such as replenishing, replacing, and adjusting the first reactants 130, 130', and 130'', which are alkali metal hydroxides such as sodium hydroxide (NaOH), and the second reactants 132, such as aluminum (Al) and zinc (Zn), as well as cleaning the reactors 100 to 500, is necessary at a certain frequency, it is possible to keep this frequency as low as possible.

[0088] For example, by making the lid member 103 easily detachable with a single touch, and by making the reactant tray 112 a cassette type, and further by automating the replenishment of the first reactant 130', 130'' which is an alkali metal hydroxide such as sodium hydroxide (NaOH) in the combustible gas generation reactors 300 to 500, it is possible to easily and quickly perform tasks such as replenishing, replacing, and adjusting the first reactant 130, 130', 130'' and the second reactant 132 such as aluminum (Al) and zinc (Zn), which is preferable. Also, during maintenance work, the remaining H generated in the above reaction formula (2) ２ The oxygen cools down and drips down into water, which is then discharged outside the reactor 100-500 via the drain pipe 115 by opening the on / off valve 115a.

[0089] In the above-described combustible gas generating reactors 100 to 500, the reactor body 102 and lid member 103 were explained using steel, particularly stainless steel, as an example. However, the reactor body 102 and lid member 103 are not limited to steel; any heat-resistant material may be used, such as ceramic. Furthermore, if a highly corrosion-resistant material such as ceramic is used for the reactor body 102, it is considered that the carbon body 105 does not necessarily need to be held on the inner surface of the furnace perimeter wall 104 of the reactor body 102.

[0090] Thus, according to the carbon dioxide treatment system of the first embodiment of the present invention, sodium hydroxide (NaOH) and carbon dioxide (CO2) in the carbon dioxide-containing exhaust gas are treated in the first reactor 20. ２ ) from sodium carbonate (Na ２ CO ３ ) is generated, and in the bipolar membrane electrodialysis apparatus 70, sodium carbonate (Na) produced in the first reactor 20 is used. ２ CO ３(aq)) from which sodium hydroxide (NaOH) and high-purity carbon dioxide (CO) are extracted. ２ (Approximately 100%) can be extracted.

[0091] Therefore, according to the carbon dioxide treatment system of the first embodiment of the present invention, carbon dioxide (CO2) in the carbon dioxide-containing exhaust gas is treated in the first reactor 20. ２ ) to sodium carbonate (Na ２ CO ３ ) is used to generate carbon dioxide (CO ２ While reducing the emission of carbon dioxide (CO2) into the atmosphere, carbon dioxide (CO2) is also reduced from exhaust gas containing carbon dioxide. ２ ) Other gas components (N ２ It eliminates (etc.) and easily produces high-purity carbon dioxide (CO2). ２ : Approximately 100%) only hydrogen (H ２ It can be effectively used to generate flammable gases such as ).

[0092] Then, the sodium hydroxide (NaOH) obtained via the bipolar membrane electrodialysis apparatus 70 is returned to the sodium hydroxide storage tank 27 and circulated to the first reactor 20, where it is used to remove carbon dioxide (CO2) from the carbon dioxide-containing exhaust gas. ２ It can be repeatedly used in reactions with ).

[0093] In addition, in the combustible gas generation reactors 100 to 500, sodium carbonate (Na) is used as the residue in the above reaction equation (2). ２ CO ３ ) is produced, but sodium carbonate (Na) is used as a residue. ２ CO ３ ) may be introduced into the bipolar membrane electrodialysis machine 70.

[0094] [Second Embodiment] Figure 9 shows a carbon dioxide treatment system 2 according to a second embodiment of the present invention. In the carbon dioxide treatment system according to the present invention, the combustible gas generating apparatus is not limited to the above combustible gas generating reactors 100 to 500, but employs electric field technology to process the carbon dioxide (CO2) generated in the bipolar membrane electrodialysis apparatus 70. ２ From approximately 100%), carbon monoxide (CO) and hydrogen (H) are released as combustible gases. ２ The combustible gas generator may be configured to produce ).

[0095] In the second embodiment, the only difference from the first embodiment is that the combustible gas generation reactor 100 is replaced with an electric field device 150. Parts common to both embodiments are given the same reference numerals and their explanation is omitted; only the electric field device 150 will be described. Referring to Figure 10, the electric field device (combustible gas generation device) 150 according to the second embodiment is shown.

[0096] As shown in Figure 10, the electric field device 150 is connected to the electric field generating power circuit 154, and an electric field generating electrode 156 capable of generating a discharge by generating and applying a DC electric field, for example using water as the electrode, is installed inside the container 152, and carbon dioxide (CO2) is placed inside the container 152. ２ By supplying carbon dioxide (CO2) and discharging it through the electric field generating electrode 156, carbon dioxide (CO2) is produced. ２ ) Carbon monoxide (CO) and hydrogen (H ２ It is configured to be able to be decomposed into (CO2). Specifically, the electric field device 150 is set to an environment where water / water vapor / superheated water vapor is present at a temperature of 100°C or higher, and under this environment carbon dioxide (CO2) is present. ２ By introducing ), carbon dioxide (CO2) ２ ) produce carbon monoxide (CO) and hydrogen (H ２ It is broken down into:

[0097] As the electric field generating power supply circuit 154, a known type that generates a DC electric field is used, and a detailed explanation is omitted here. Container 152 contains carbon dioxide (CO2). ２ A carbon dioxide inlet pipe 158 is provided to supply carbon monoxide (CO) and hydrogen (H) into the container 152. ２ A combustible gas outlet pipe 160 is provided for discharging the gas.

[0098] The carbon dioxide inlet pipe 158 is connected to the carbon dioxide outlet 76 of the bipolar membrane electrodialysis machine 70 via a hose, and the combustible gas outlet pipe 160 is connected to a carbon monoxide storage tank or a hydrogen storage tank (neither shown) via a hose. The carbon dioxide inlet pipe 158 is provided with an on / off valve 158a that can open and close the internal passage, and the combustible gas outlet pipe 160 is provided with an on / off valve 160a that can open and close the internal passage, and the on / off valves 158a and 160a are connected to a control device and controlled by the control device.

[0099] [Operation of the electric field device 150] (combustible gas generation process) In the electric field device 150, which acts as a combustible gas generation device, opening the on / off valve 158a generates carbon dioxide (CO ２ ) is supplied into the container 152 of the electric field device 150 via the carbon dioxide inlet pipe 158.

[0100] In the electric field device 150, the discharge action of the electric field generated from the electric field generating power circuit 154 through the electric field generating electrode 156 generates carbon dioxide (CO2). ２ ) produce carbon monoxide (CO) and hydrogen (H ２ ) are broken down into ). Then, by opening the on / off valve 160a, carbon monoxide (CO) and hydrogen (H) are released. ２ The gas is discharged from the combustible gas outlet pipe 160 and stored in a carbon monoxide storage tank or a hydrogen storage tank.

[0101] As a result, similar to the first embodiment described above, the carbon dioxide (CO) in the carbon dioxide-containing exhaust gas is released in the first reactor 20. ２ ) and sodium carbonate (Na ２ CO ３ ) is used to generate carbon dioxide (CO ２ While reducing the release of carbon dioxide (CO2) into the atmosphere, carbon dioxide (CO2) is also released from exhaust gases containing carbon dioxide. ２ ) Other gas components (N ２ It eliminates (etc.) and easily produces high-purity carbon dioxide (CO2). ２ (Approximately 100%) is extracted, and carbon monoxide (CO) and hydrogen (H) are separated. ２ It can be effectively used to generate flammable gases.

[0102] Furthermore, the sodium hydroxide (NaOH) obtained via the bipolar membrane electrodialysis apparatus 70 is returned to the sodium hydroxide storage tank 27 and circulated to the first reactor 20, where it is used to remove carbon dioxide (CO2) from the carbon dioxide-containing exhaust gas. ２ It can be repeatedly used in reactions with ). Note that, although the example given here is the case where the electric field device 150 generates a DC electric field, the electric field device is not limited to those that generate a DC electric field; it may also generate an AC electric field if a similar effect can be obtained.

[0103] [Third Embodiment] Figure 11 is a diagram showing a carbon dioxide treatment system 3 according to the third embodiment of the present invention. As shown in Figure 11, the carbon dioxide treatment system 3 according to the third embodiment of the present invention mainly comprises: an exhaust gas pretreatment device 10 for pretreatment of carbon dioxide-containing exhaust gas; a first reactor 20 for reacting alkali metal hydroxide with carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates; a second reactor 40 for containing the alkali metal carbonates produced in the first reactor 20 and supplying carbon dioxide-containing exhaust gas containing carbon dioxide to react alkali metal hydroxide with carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal bicarbonate (baking soda); a third reactor 60 for decomposing the alkali metal bicarbonate produced in the second reactor 40 to produce alkali metal carbonate and carbon dioxide; a fourth reactor (alkali metal carbonate decomposition device) 80 for decomposing the alkali metal carbonates produced in the third reactor 60 to produce alkali metal hydroxides; and a combustible gas generation reactor 100 for generating combustible gas using the carbon dioxide produced in the third reactor 60.

[0104] In the carbon dioxide treatment system 3 according to the third embodiment, the exhaust gas pretreatment device 10, the first reactor 20, and the combustible gas generation reactor 100 are common to the carbon dioxide treatment system 1 according to the first embodiment. The same reference numerals are used for the common parts and their descriptions are omitted. The following description will focus on the second reactor 40, the third reactor 60, and the fourth reactor 80, which differ from those in the first embodiment.

[0105] Referring to Figure 12, the second reactor 40 is shown. As shown in Figure 12, the second reactor 40 consists mainly of a reactor body 41 which is a cylindrical casing. The furnace perimeter wall of the reactor body 41 contains alkali metal carbonates as reactants, such as sodium carbonate (Na) ２ CO ３ ) Sodium carbonate inlet 42 for adding water (H ２ An inlet 43 for introducing O) is provided, and an exhaust gas inlet pipe (second exhaust gas inlet) 44 is provided, which is connected to the pretreatment device 10 via an on / off valve 44a that can open and close the internal passage to open and close it, and a hose, etc., and supplies exhaust gas containing carbon dioxide that has been pretreated in the pretreatment device 10.

[0106] Furthermore, alkali metal bicarbonates, such as sodium bicarbonate (NaHCO3), generated from within the reactor body 41 are also supplied to the reactor body 41. ３ A sodium bicarbonate outlet 45 for discharging ) and a gas component outlet 47 for discharging the remaining gas component of the carbon dioxide-containing exhaust gas after the carbon dioxide has been used are provided.

[0107] The sodium carbonate inlet 42 is connected to the sodium carbonate outlet 24 of the first reactor 20, and the water inlet 43 is connected to the water tank 29 via a water control device 48 that controls the water supply. The water control device 48 is connected to a control device (not shown; hereinafter simply referred to as the control device) that controls the carbon dioxide treatment system 3, and the amount and timing of water supplied to the second reactor 40 are appropriately adjusted by the water control device 48. As a result, sodium carbonate is contained in the second reactor 40 in the form of an aqueous solution.

[0108] The sodium bicarbonate outlet 45 is connected to the third reactor 60 via an on / off valve 45a, a hose, etc., which allows for opening and closing the internal passage by operating it, and the control device opens and closes the on / off valve 45a to generate sodium bicarbonate (NaHCO3). ３ For example, in the form of an aqueous solution, this is supplied to the third reactor 60.

[0109] A scavenging device 50 is provided at the gas component outlet 47, and by operating the scavenging device 50 with a control device, the remaining residual gas components (N) of the carbon dioxide-containing exhaust gas other than the carbon dioxide used in the reaction are removed. ２ It is possible to discharge (etc.) to the outside.

[0110] The reactor body 41 is made of, for example, steel. Stainless steel is often used, such as austenitic SUS303, SUS304, SUS316, or ferritic SUS430. Alternatively, the reactor body 41 may be made of a resin such as vinyl ester-based FRP.

[0111] A heating and warming device (second heating and warming section) 52 is installed inside the second reactor 40. For example, an electric heater is used as the heating and warming device 52. The electric heater's temperature can be controlled by a temperature controller (not shown) located outside the second reactor 40. A thermometer (not shown), such as a thermocouple, is installed inside the second reactor 40, and this temperature controller is also connected to the control device. This allows the ambient temperature inside the second reactor 40 to be constantly measured by the thermometer, and the ambient temperature inside the second reactor 40 to be adjusted and maintained within a second specified temperature range (0°C to 60°C).

[0112] Exhaust gas containing carbon dioxide, which has been pretreated by the exhaust gas pretreatment device 10, is supplied from the exhaust gas inlet pipe 44. A microbubble generator (second microbubble generator) 54 is also provided in the exhaust gas inlet pipe 44, and the exhaust gas is supplied to the sodium carbonate aqueous solution as microbubbles. In addition, a stirring device (second stirring device) 56 for stirring the aqueous solution is also provided in the second reactor 40, thereby stirring the sodium carbonate aqueous solution and sodium carbonate (Na ２ CO ３ ) and carbon dioxide in exhaust gas (CO ２ This promotes the reaction.

[0113] Furthermore, the second reactor 40 is used to process the generated sodium bicarbonate (NaHCO3). ３A sodium bicarbonate outlet 58 is also provided so that the sodium bicarbonate can be extracted, and the sodium bicarbonate outlet 58 is connected to the drying oven 59 via an on / off valve 58a. By operating the on / off valve 58a and drying (solid-liquid separation) in the drying oven 59, sodium bicarbonate (NaHCO3) can be extracted. ３ You can take out (solid baking soda).

[0114] Referring to Figure 13, the third reactor 60 is shown. As shown in Figure 13, the third reactor 60 consists mainly of a reactor body 61 which is a cylindrical casing. On the furnace perimeter wall of the reactor body 61, alkali metal bicarbonates produced in the second reactor 40 as reactants, such as aqueous sodium bicarbonate (NaHCO3), are placed inside the reactor body 61. ３ An input port 62 is provided for inserting (the material).

[0115] Furthermore, the reactor body 61 contains sodium carbonate (Na) generated from within the reactor body 61. ２ CO ３ ) Sodium carbonate outlet 63 for extracting carbon dioxide (CO ２ A carbon dioxide outlet 64 is provided for discharging carbon dioxide. The carbon dioxide outlet 64 is connected to the combustible gas generating reactor 100.

[0116] The reactor body 61 is made of, for example, steel. Stainless steel is often used, such as austenitic SUS303, SUS304, SUS316, or ferritic SUS430. Alternatively, the reactor body 61 may be made of a resin such as high heat-resistant vinyl ester FRP.

[0117] A heating and warming device (third heating and warming section) 65 is installed inside the third reactor 60. For example, an electric heater is used as the heating and warming device 65. The electric heater's temperature can be controlled by a temperature controller (not shown) located outside the third reactor 60. A thermometer (not shown), such as a thermocouple, is installed inside the third reactor 60, and this temperature controller is also connected to the control device. This allows the ambient temperature inside the third reactor 60 to be constantly measured by the thermometer, and the ambient temperature inside the third reactor 60 to be adjusted and maintained within the third specified temperature range (100°C to 150°C).

[0118] Furthermore, the third reactor 60 is also equipped with a stirring device (third stirring device) 66 for stirring the aqueous solution, thereby stirring the aqueous solution of sodium bicarbonate (NaHCO3). ３ Sodium carbonate (Na) ２ CO ３ ) and carbon dioxide (CO ２ This promotes the breakdown of the substance into ).

[0119] Referring to Figure 14, the fourth reactor 80 is shown. As shown in Figure 14, the fourth reactor 80 consists mainly of a reactor body 81 which is a cylindrical casing. The furnace perimeter wall of the reactor body 81 contains alkali metal carbonates as reactants, such as sodium carbonate (Na) ２ CO ３ ) Sodium carbonate inlet 82 for adding water (H ２ A water inlet 83 for adding O) is provided, and calcium hydroxide (Ca(OH) ２ A calcium hydroxide inlet 84 is provided to supply calcium hydroxide.

[0120] Furthermore, the reactor body 81 includes a sodium hydroxide outlet 85 for removing sodium hydroxide (NaOH) generated inside the reactor body 81 and a calcium carbonate (CaCO2) outlet. ３ A calcium carbonate outlet 86 is provided for extracting calcium carbonate.

[0121] The third reactor 60 is connected to the sodium carbonate inlet 82, and the water tank 29 is connected to the water inlet 83 via a water control device 87 that controls the water supply. In addition, the calcium hydroxide tank 89 is connected to the calcium hydroxide inlet 84 via a calcium hydroxide control device 88 that controls the supply of calcium hydroxide, for example. The water control device 87 and the calcium hydroxide control device 88 are connected to a control device, and the amount and timing of the water and calcium hydroxide supplied to the fourth reactor 80 are appropriately adjusted by the water control device 87 and the calcium hydroxide control device 88. As a result, the fourth reactor 80 contains sodium carbonate and calcium hydroxide in aqueous solution form.

[0122] The sodium hydroxide outlet 85 is connected to the sodium hydroxide storage tank 27 via an on / off valve 85a, a hose, etc., which allows the internal passage to be opened and closed by an on / off operation. The sodium hydroxide (NaOH) generated by opening and closing the on / off valve 85a by the control device is returned to the sodium hydroxide storage tank 27 and circulated to the first reactor 20. The calcium carbonate outlet 86 is provided with an on / off valve 86a, and the generated calcium carbonate (CaCO3) is returned by opening the on / off valve 86a as appropriate. ３ ) can be extracted.

[0123] The reactor body 81 is constructed of, for example, steel. Stainless steel is preferred, such as austenitic SUS303, SUS304, SUS316, or ferritic SUS430. The inner surface of the furnace perimeter wall of the reactor body 81 is coated with an alkali-resistant coating or glass lining to cover the perimeter wall. Alternatively, the reactor body 81 may be made of a resin such as vinyl ester-based FRP.

[0124] A heating and warming device (fourth heating and warming section) 90 is installed inside the fourth reactor 80. For example, an electric heater is used as the heating and warming device 90. The electric heater's temperature can be controlled by a temperature controller (not shown) located outside the fourth reactor 80. A thermometer (not shown), such as a thermocouple, is installed inside the fourth reactor 80, and this temperature controller is also connected to the control device. This allows the ambient temperature inside the fourth reactor 80 to be constantly measured by the thermometer, and the ambient temperature inside the fourth reactor 80 to be adjusted and maintained within the fourth specified temperature range (approximately 45°C to 80°C).

[0125] The fourth reactor 80 is also equipped with a stirring device 92 for stirring the aqueous solution, thereby stirring the aqueous solution of sodium carbonate and calcium hydroxide and promoting the reaction between sodium carbonate and calcium hydroxide.

[0126] The operation of the carbon dioxide treatment system according to the third embodiment configured as described above, that is, the carbon dioxide treatment method, will be explained below. In the carbon dioxide treatment system 3 according to the third embodiment, the operation of the exhaust gas pretreatment device 10, the first reactor 20, and the combustible gas generation reactor 100 is the same as that of the carbon dioxide treatment system 1 according to the first embodiment, so the explanation of the common parts will be omitted, and the operation of the second reactor 40, the third reactor 60, and the fourth reactor 80, which differ from those of the first embodiment, will be explained below.

[0127] [Operation of the second reactor 40] (Second reaction process) In the second reactor 40, sodium carbonate (Na) produced in the first reactor 20 is processed. ２ CO ３ The sodium carbonate is introduced into the reactor body 41 through the sodium carbonate inlet 42, and the water control device 48 is operated to introduce water through the water inlet 43. As a result, the second reactor 40 is now filled with sodium carbonate in an aqueous solution.

[0128] Then, the on / off valve 44a is opened, and the exhaust gas containing carbon dioxide, which has been pretreated in the pretreatment device 10, is supplied as microbubbles (bubbles) from the exhaust gas inlet pipe 44 into the aqueous sodium carbonate solution by the microbubble generator 54. In addition, the ambient temperature inside the second reactor 40 is adjusted to a second specified temperature range (for example, 0°C to 60°C) by the heating and warming device 52.

[0129] As a result, the following reaction occurs in the second reactor 40, producing sodium bicarbonate (NaHCO3). ３ ) is generated. ２ CO ３ +CO ２ +H ２ O → 2NaHCO ３ ... (5) In this way, sodium bicarbonate (NaHCO) ３ When ) is generated, the scavenging device 50 is operated to release the remaining residual gas components (N) from the carbon dioxide-containing exhaust gas other than the carbon dioxide used in the reaction from the gas component outlet 47. ２ All of the above (etc.) are discharged to the outside.

[0130] The resulting sodium bicarbonate (NaHCO) ３ The solution is discharged from the sodium bicarbonate outlet 45 when the on / off valve 45a is opened, and supplied to the third reactor 60 in aqueous solution form.

[0131] Sodium bicarbonate (NaHCO2) produced in the second reactor 40 ３ ) is supplied to the drying oven 59 from the sodium bicarbonate discharge port 58 by opening the on / off valve 58a, where it is dried (solid-liquid separation), and the sodium bicarbonate (NaHCO₃) is dried. ３ It can also be extracted and used effectively as solid baking soda.

[0132] In this case, sodium bicarbonate (NaHCO2) is used in the second reactor 40. ３ The process is divided to produce sodium bicarbonate (NaHCO3), but by continuously supplying carbon dioxide-containing exhaust gas to the first reactor 20 without dividing the process, i.e., the reactor, sodium bicarbonate (NaHCO3) can be produced. ３ It is also possible to generate ( ).

[0133] [Operation of the third reactor 60] (Third reaction step) In the third reactor 60, aqueous sodium bicarbonate (NaHCO3) produced in the second reactor 40 is used. ３ The sodium bicarbonate is introduced into the reactor body 61 through the sodium bicarbonate inlet 62. The ambient temperature inside the third reactor 60 is then raised to the third specified temperature range (for example, 100°C to 150°C).

[0134] As a result, sodium bicarbonate (NaHCO3) produced in the second reactor 40 ３ ) is produced when the reverse decomposition reaction of the above reaction equation (5), shown in equation (6), occurs, resulting in sodium carbonate (Na ２ CO ３ ) and carbon dioxide (CO ２ ) and water (H ２ It is broken down into 2NaHCO3. ３ →Na ２ CO ３ +CO ２ +H ２ O... (6)

[0135] The carbon dioxide (CO2) is thus broken down. ２ ) is the original carbon dioxide (CO ２ Unlike exhaust gas containing carbon dioxide (CO20%), which contains approximately 20%, this is high-purity carbon dioxide (CO2). ２ : Approximately 100%, which is discharged from the carbon dioxide outlet 64 and supplied to the combustible gas generation reactor 100. ２ CO ３ The sodium carbonate is discharged from the sodium carbonate outlet 63 when the on / off valve 63a is opened and supplied to the fourth reactor 80.

[0136] [Operation of the fourth reactor 80] (Alkali metal carbonate decomposition process) In the fourth reactor 80, sodium carbonate (Na) is supplied from the third reactor 60 through the sodium carbonate inlet 82. ２ CO ３ ) is supplied, and water is poured in from the water tank 29 via the water inlet 83, and the calcium hydroxide operating device 88 is operated so that calcium hydroxide (Ca(OH)) is poured from the calcium hydroxide tank 89 via the calcium hydroxide inlet 84. ２) is supplied. As a result, sodium carbonate and calcium hydroxide are contained in aqueous solution in the fourth reactor 80.

[0137] In the fourth reactor 80, sodium carbonate (Na ２ CO ３ ) and calcium hydroxide (Ca(OH) ２ The following reaction occurs between ) and calcium carbonate (CaCO2), producing sodium hydroxide (NaOH) and calcium carbonate (CaCO2). ３ ) and are produced. Na ２ CO ３ + Ca(OH) ２ →2NaOH+CaCO ３ ... (7)

[0138] In this way, the sodium hydroxide (NaOH) produced in the fourth reactor 80 is discharged from the sodium hydroxide outlet 85 when the on / off valve 85a is opened, returned to the sodium hydroxide storage tank 27, and circulated to the first reactor 20. In addition, the calcium carbonate (CaCO3) produced in the fourth reactor 80 ３ The calcium carbonate can be appropriately removed from the calcium carbonate outlet 86 and effectively utilized.

[0139] Thus, in the carbon dioxide treatment system according to the third embodiment of the present invention, sodium hydroxide (NaOH) and carbon dioxide (CO2) in the carbon dioxide-containing exhaust gas are treated in the first reactor 20. ２ ) from sodium carbonate (Na ２ CO ３ ) is produced, and in the second reactor 40, sodium carbonate (Na) produced in the first reactor 20 is converted. ２ CO ３ ) and carbon dioxide in carbon dioxide-containing exhaust gas (CO ２ ) and sodium bicarbonate (2NaHCO) ３ (Baking soda) is produced, and in the third reactor 60, sodium bicarbonate (2NaHCO2) produced in the second reactor 40 is used. ３ ) to sodium carbonate (Na ２ CO ３ ) and carbon dioxide (CO ２ It is broken down into high-purity carbon dioxide (CO2). ２ Approximately 100% can be extracted.

[0140] Therefore, according to the carbon dioxide treatment system of the third embodiment of the present invention, carbon dioxide (CO2) in the carbon dioxide-containing exhaust gas is treated in both the first reactor 20 and the second reactor 40. ２ ) are each sodium carbonate (Na ２ CO ３ ) and sodium bicarbonate (NaHCO) ３ ) is used to generate carbon dioxide (CO ２ While reducing the release of ) into the atmosphere, sodium bicarbonate (NaHCO3) is removed from carbon dioxide-containing exhaust gases. ３ Through the process of generating ), carbon dioxide (CO2) is produced. ２ ) Other gas components (N ２ (etc.) are eliminated, and high-purity carbon dioxide (CO) is easily produced in the third reactor 60. ２ : Approximately 100% is extracted, and this high-purity carbon dioxide (CO2) is used. ２ : Approximately 100%) hydrogen (H ２ It can be effectively used to generate flammable gases such as ).

[0141] Furthermore, the high-purity carbon dioxide (CO2) obtained in this way ２ Approximately 100% of the sodium bicarbonate (NaHCO3) is refluxed to the first reactor 20 and the second reactor 40. ３ It may also be used to contribute to the production of sodium carbonate (Na) produced in the third reactor 60. ２ CO ３ When this is refluxed to the first reactor 20 and the second reactor 40, sodium bicarbonate (NaHCO) is produced in the first reactor 20 and the second reactor 40. ３ It can produce baking soda.

[0142] Furthermore, sodium bicarbonate (NaHCO3) produced and dried in the second reactor 40 ３ ) (solid baking soda) and calcium carbonate (CaCO2) produced in the fourth reactor 80 ３ The sodium hydroxide (NaOH) obtained via the fourth reactor 80 is returned to the sodium hydroxide storage tank 27 and circulated back to the first reactor 20, where it is used to remove carbon dioxide (CO2) from the carbon dioxide-containing exhaust gas.２ It can be repeatedly used in reactions with ).

[0143] [First to Fourth Modifications of the Third Embodiment] In the third embodiment, as in the case of the first embodiment, with respect to the combustible gas generating apparatus, the combustible gas generating reactors 200 to 500 related to the first to fourth modifications shown as the first to fourth modifications of the first embodiment may be adopted as the first to fourth modifications of the third embodiment, instead of the combustible gas generating reactor 100.

[0144] In addition, in the combustible gas generation reactors 100 to 500, sodium carbonate (Na) is used as the residue in the above reaction equation (2). ２ CO ３ ) is produced, but sodium carbonate (Na) is used as a residue. ２ CO ３ ) may be introduced into the second reactor 40.

[0145] [Fourth Embodiment] Figure 14 shows a carbon dioxide gas processing system 4 according to the fourth embodiment of the present invention. In the fourth embodiment, similar to the second embodiment, the electric field device 150 shown in Figure 10 is used instead of the combustible gas generation reactors 100 to 500, and the carbon dioxide gas (CO2) produced in the third reactor 60 is processed. ２ Approximately 100% of the total volume is converted into carbon monoxide (CO) and hydrogen (H) as combustible gases. ２ The combustible gas generator may be configured to produce ).

[0146] As described above in the first to fourth embodiments, the carbon dioxide treatment system and treatment method according to the present invention allows for the treatment of alkali metal hydroxides, such as sodium hydroxide (NaOH), and carbon dioxide (CO2). ２ ) is used to produce alkali metal carbonates, such as sodium carbonate (Na ２ CO ３ ) and sodium bicarbonate (NaHCO) ３ ) generates carbon dioxide (CO) in carbon dioxide-containing exhaust gas. ２ While effectively reducing the release of ) into the atmosphere, high-purity carbon dioxide (CO2) ２ : Approximately 100%) only hydrogen (H ２It can be effectively used to generate flammable gases such as carbon dioxide (CO) and carbon monoxide (CO), and the alkali metal hydroxides, such as sodium hydroxide (NaOH), produced in the process of generating high-purity carbon dioxide can be recycled and reused, resulting in energy savings and low costs for carbon dioxide-containing exhaust gas (CO). ２ It is possible to process large quantities of these efficiently.

[0147] Furthermore, according to the carbon dioxide treatment apparatus (combustible gas generation reactor 100-500) of the present invention, carbon dioxide (CO ２ While effectively reducing ) hydrogen (H) as a combustible gas, ２ This enables efficient generation of carbon dioxide (CO2). ２ To maintain and improve the reduction rate of hydrogen (H), a useful substance, efficiently ２ It is possible to continuously generate ). In the first to fourth embodiments described above, the case in which the alkali metal is sodium (Na) was mainly explained as an example, but the alkali metal may also be potassium (K).

[0148] The carbon dioxide treatment system, treatment method, and treatment apparatus of the present invention are used to treat carbon dioxide (CO2), a greenhouse gas that is one of the causes of global warming. ２ ) efficiently reduces hydrogen (H) which is a useful substance. ２ This is an excellent technology that can generate combustible gases such as ) and ). Therefore, by applying this technology, the separated and recovered carbon dioxide (CO2) can be recovered. ２ The technology of CCS (Carbon dioxide Capture and Storage), which involves storing and injecting hydrogen (H) deep underground, becomes unnecessary, making it possible to drastically reduce costs, while also eliminating the need for hydrogen (H) technology, which is a useful substance. ２ ) generates flammable gases such as hydrogen (H) ２ This can make a very significant contribution to the demand for ).

[0149] For example, by applying the carbon dioxide treatment system, treatment method, and treatment apparatus of the present invention to the exhaust gas of combustion gases generated as industrial waste in various industrial fields such as incinerators, steel mills, thermal power plants, large boilers, and internal combustion engines, carbon dioxide (CO2) can be treated. ２As soon as it is generated, carbon dioxide (CO2) is released. ２ ) can be processed almost completely, and the generated hydrogen (H ２ Combustible gases such as ) can be effectively utilized as fuel sources.

[0150] 1, 2, 3, 4 Carbon Dioxide Treatment System 10 Exhaust Gas Pretreatment Device 20 First Reactor 23 Exhaust Gas Inlet Pipe (First Exhaust Gas Inlet) 27 Sodium Hydroxide Storage Tank 32 Heating and Warming Device (First Heating and Warming Section) 34 Microbubble Generator (First Microbubble Generator) 36 Stirring Device (First Stirring Device) 40 Second Reactor 44 Exhaust Gas Inlet Pipe (Second Exhaust Gas Inlet) 52 Heating and Warming Device (Second Heating and Warming Section) 54 Microbubble Generator (Second Microbubble Generator) 56 Stirring Device (Second Stirring Device) 60 Third Reactor 65 Heating and Warming Device (Third Heating and Warming Section) 66 Stirring Device (Third Stirring Device) 70 Bipolar Membrane Electrodialysis Machine (BMED) (Alkali Metal Carbonate Decomposition Device) 80 Fourth Reactor (Alkali Metal Carbonate Decomposition Device) 90 Heating and warming device (4th heating and warming section) 100, 200, 300, 400, 500 Combustible gas generation reactor (combustible gas generation device, reactor, carbon dioxide gas treatment device) 106 Heating section (5th heating and warming section) 107 Carbon dioxide gas inlet pipe 108 Treatment gas outlet pipe 130, 130′, 130″ First reactant 132 Second reactant 140 Stirring device 150 Electric field device (combustible gas generation device)

Claims

1. A carbon dioxide treatment system comprising: a first reactor that contains alkali metal hydroxides including alkali metals and is equipped with a first exhaust gas inlet for supplying carbon dioxide-containing exhaust gas containing carbon dioxide, and reacts the alkali metal hydroxides with the carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates including alkali metals; an alkali metal carbonate decomposition device that decomposes the alkali metal carbonates produced in the first reactor to produce alkali metal hydroxides and carbon dioxide; and a combustible gas generation device that uses the carbon dioxide produced in the alkali metal carbonate decomposition device to produce combustible gas, wherein the alkali metal hydroxides produced in the alkali metal carbonate decomposition device are circulated back to the first reactor.

2. A first reactor containing alkali metal hydroxides including alkali metals and equipped with a first exhaust gas inlet for supplying carbon dioxide-containing exhaust gas, which reacts the alkali metal hydroxides with the carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal carbonates including alkali metals; a second reactor containing the alkali metal carbonates produced in the first reactor and equipped with a second exhaust gas inlet for supplying carbon dioxide-containing exhaust gas, which reacts the alkali metal carbonates with the carbon dioxide in the carbon dioxide-containing exhaust gas to produce alkali metal bicarbonates (baking soda) including alkali metals; a third reactor decomposing the alkali metal bicarbonates produced in the second reactor to produce alkali metal carbonates and carbon dioxide; an alkali metal carbonate decomposition device decomposing the alkali metal carbonates produced in the third reactor to produce alkali metal hydroxides; and a combustible gas generator using the carbon dioxide produced in the third reactor to produce combustible gas. A carbon dioxide treatment system characterized by circulating the alkali metal hydroxide produced in the alkali metal carbonate decomposition apparatus back to the first reactor.

3. The carbon dioxide treatment system according to claim 1 or 2, wherein the first reactor comprises a first heating and warming unit that maintains the internal ambient temperature within a first specified temperature range, and while the ambient temperature is maintained within the first specified temperature range by the first heating and warming unit, the carbon dioxide in the carbon dioxide-containing exhaust gas is reacted with the alkali metal hydroxide to produce an alkali metal carbonate.

4. The carbon dioxide treatment system according to claim 3, characterized in that, inside the first reactor, the alkali metal hydroxide is held as an aqueous solution of 20 to 30% by mass; a first microbubble generator is provided at the first exhaust gas inlet for supplying the carbon dioxide-containing exhaust gas into the first reactor as microbubbles; a first stirring device is provided inside the first reactor for stirring the aqueous solution; and the first specified temperature range is 0°C to 60°C.

5. The carbon dioxide treatment system according to claim 2, wherein the second reactor comprises a second heating and warming section capable of maintaining the internal ambient temperature within a second specified temperature range, and while the ambient temperature is maintained within the second specified temperature range by the second heating and warming section, the alkali metal carbonate is reacted with the carbon dioxide in the carbon dioxide-containing exhaust gas to produce an alkali metal bicarbonate (baking soda).

6. The carbon dioxide treatment system according to claim 5, characterized in that, inside the second reactor, the alkali metal carbonate is held as an aqueous solution; a second microbubble generator is provided at the second exhaust gas inlet for supplying the carbon dioxide-containing exhaust gas into the second reactor as microbubbles; a second stirring device is provided inside the second reactor for stirring the aqueous solution; and the second specified temperature range is 0°C to 60°C.

7. The carbon dioxide treatment system according to claim 2, wherein the third reactor comprises a third heating and warming section capable of maintaining the internal ambient temperature within a third specified temperature range, and the alkali metal bicarbonate (baking soda) is decomposed to produce alkali metal carbonate and carbon dioxide while the ambient temperature is maintained within the third specified temperature range by the third heating and warming section.

8. The carbon dioxide treatment system according to claim 7, characterized in that the alkali metal bicarbonate is held as an aqueous solution inside the third reactor, a third stirring device for stirring the aqueous solution is provided inside the third reactor, and the third specified temperature range is 100°C to 150°C.

9. The carbon dioxide treatment system according to claim 1, characterized in that the alkali metal carbonate decomposition apparatus is a bipolar membrane electrodialysis apparatus (BMED) that decomposes the alkali metal carbonate into alkali metal hydroxide and carbon dioxide by bipolar membrane electrodialysis.

10. The alkali metal carbonate decomposition apparatus has a fourth reaction furnace comprising a fourth heating and warming section that houses the alkali metal carbonate and calcium hydroxide and maintains the internal ambient temperature within a fourth specified temperature range, wherein the fourth reaction furnace reacts the alkali metal carbonate and calcium hydroxide to produce alkali metal hydroxide while maintaining the ambient temperature within the fourth specified temperature range by the fourth heating and warming section, the carbon dioxide treatment system according to claim 2.

11. The carbon dioxide gas processing system according to claim 1 or 2, characterized in that the combustible gas generating apparatus is a sealed combustible gas generating reactor equipped with a carbon dioxide gas inlet for supplying carbon dioxide gas to the interior and a processed gas outlet for discharging processed gas containing the combustible gas after processing, and comprises a fifth heating and warming section for raising the internal ambient temperature to a predetermined temperature or higher, and a reaction material tray on which a first reaction material consisting of an alkali metal hydroxide containing an alkali metal and a second reaction material consisting of at least aluminum or zinc are placed, and the carbon dioxide gas is reacted with the first reaction material and the second reaction material to generate processed gas containing the combustible gas while the ambient temperature is maintained at or above the predetermined temperature by the fifth heating and warming section.

12. The carbon dioxide treatment system according to claim 1 or 2, wherein the combustible gas generating device is an electric field device consisting of carbon dioxide and water, and the electric field device discharges electricity in an environment where water / water vapor / superheated water vapor is present and the ambient temperature is 100°C or higher, thereby generating carbon monoxide and hydrogen from carbon dioxide and water.

13. The carbon dioxide treatment system according to any one of claims 1 to 12, characterized in that the alkali metal is mainly sodium or potassium.

14. A method for treating carbon dioxide, characterized by: a first reaction step of reacting an alkali metal hydroxide with carbon dioxide in a carbon dioxide-containing exhaust gas to produce an alkali metal carbonate; an alkali metal carbonate decomposition step of decomposing the alkali metal carbonate produced in the first reaction step to produce an alkali metal hydroxide and carbon dioxide; a combustible gas production step of producing a combustible gas using the carbon dioxide produced in the alkali metal carbonate decomposition step; and circulating the alkali metal hydroxide produced in the alkali metal carbonate decomposition step back to the first reaction step.

15. A method for treating carbon dioxide, comprising: a first reaction step of reacting alkali metal hydroxide with carbon dioxide in carbon dioxide-containing exhaust gas to produce alkali metal carbonate; a second reaction step of reacting the alkali metal carbonate produced in the first reaction step with carbon dioxide in carbon dioxide-containing exhaust gas to produce alkali metal bicarbonate (baking soda); a third reaction step of decomposing the alkali metal bicarbonate produced in the second reaction step to produce alkali metal carbonate and carbon dioxide; an alkali metal carbonate decomposition step of decomposing the alkali metal carbonate produced in the third reaction step to produce alkali metal hydroxide; a combustible gas production step of producing combustible gas using the carbon dioxide produced in the third reaction step; and a method for treating carbon dioxide, characterized by circulating the alkali metal hydroxide produced in the alkali metal carbonate decomposition step back to the first reaction step.

16. A carbon dioxide processing apparatus comprising: a sealed reactor having a carbon dioxide inlet for supplying carbon dioxide gas to the interior and a processed gas outlet for discharging processed gas containing combustible gas after processing; a heating unit for raising the ambient temperature inside the reactor to a predetermined temperature or higher; and a reactant tray provided inside the reactor, on which a first reactant made of alkali metal hydroxide and a second reactant made of at least aluminum or zinc are placed.

17. The carbon dioxide treatment apparatus according to claim 16, characterized in that it is provided with an injection nozzle disposed on the periphery wall of the reactor for injecting liquid or granular alkali metal hydroxide as the first reactant into the interior of the reactor.

18. The carbon dioxide processing apparatus according to claim 17, characterized in that the first reactant consists of granular alkali metal hydroxide, and the injection nozzle simultaneously injects the first reactant and the carbon dioxide into the reactor.

19. The carbon dioxide treatment apparatus according to any one of claims 16 to 18, characterized in that the reactor is made of steel and a carbon body is arranged along the inner surface of the furnace periwall of the reactor.

20. The carbon dioxide apparatus according to claim 19, characterized in that the first reactant is sodium hydroxide or potassium hydroxide.

21. The carbon dioxide apparatus according to claim 20, characterized in that the second reactant consists of a plurality of small pieces or a plurality of pellet-shaped particles of at least aluminum or zinc.

22. The carbon dioxide gas processing apparatus according to claim 20, characterized in that the reactant tray is located directly above the heating section.

23. The carbon dioxide gas treatment apparatus according to claim 20, characterized in that a stirring device is provided inside the reactor.

24. The carbon dioxide treatment apparatus according to claim 20, characterized in that the flammable gas is hydrogen.

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