Calcium oxide production device and production method

Abstract

To provide a device and a method for producing calcium oxide by chemical reaction with carbon dioxide, water, sodium, and a catalyst including iron as a main component in a reaction tank used for firing calcium carbonate, with reduced carbon dioxide emission.SOLUTION: A calcium oxide production device for producing calcium oxide from calcium carbonate is composed of a reaction tank, a charging route, discharge routes, and an auxiliary heater. The calcium oxide production device is configured so that the calcium carbonate, water, and iron as a catalyst are charged into the reaction tank, the inside of the reaction tank is heated with the auxiliary heater followed by charging sodium, and the calcium oxide, hydrogen, and sodium carbonate finally produced by chemical reaction are discharged from the respective discharge routes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method for producing calcium oxide, and more particularly to an apparatus and method for producing calcium oxide that efficiently produces calcium oxide. [Background technology]

[0002] Quicklime (calcium oxide) has been widely used in various industries, such as in mortar for construction and as a pH adjuster for acidic soil. It is known that when calcium carbonate is calcined during the calcium oxide production process, carbon dioxide is also produced simultaneously with the production of calcium oxide. Many methods have been published for reducing or adsorbing the carbon dioxide produced.

[0003] However, when the above method is used, multiple tanks are required for calcium oxide production, which often results in large-scale equipment and reduced efficiency in calcium oxide production, and therefore it has not been a fundamental solution. Therefore, there was a need for a production method that would reduce the release of carbon dioxide during calcium oxide production in a single tank.

[0004] To solve the above problems, a technical proposal has been made in JP 2022-96876 A (Patent Document 1). Specifically, this technical proposal uses a limestone calciner and a catalyst to react carbon dioxide gas with hydrogen gas to produce methane.

[0005] However, the technical proposal described in Patent Document 1 requires the installation of a methane generation device that reacts carbon dioxide-containing gas with hydrogen, separate from the calcination furnace, and does not solve the problem.

[0006] Therefore, the present applicant focused on the carbon dioxide generated during the production of calcium oxide, and came up with the idea that it might be possible to reduce the amount of carbon dioxide emitted into the atmosphere by decomposing the carbon dioxide generated within the pressure vessel. He developed a method and apparatus for producing calcium oxide as well as sodium carbonate and hydrogen within the pressure vessel by chemically reacting the carbon dioxide generated during the calcination of calcium carbonate with water and sodium, which led to the proposal of the "calcium oxide production apparatus and production method" of the present invention. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2022-96876 Summary of the Invention [Problem to be solved by the invention]

[0008] In view of the above problems, an object of the present invention is to provide an apparatus and a method for producing calcium oxide with reduced carbon dioxide emissions through a chemical reaction between carbon dioxide, water, sodium, and a catalyst containing iron as a main component in a reaction tank used for calcining calcium carbonate. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention provides a method for producing calcium oxide from calcium carbonate, which comprises the following steps: a calcium carbonate introduction step of introducing calcium carbonate, water, and iron as a catalyst into a reaction tank consisting of a pressure vessel; an auxiliary heating step of raising the temperature inside the reaction tank to 950°C; a first reaction step of introducing sodium into the vessel, generating carbon dioxide when producing calcium oxide from calcium carbonate, reacting with water and sodium to generate sodium bicarbonate and sodium hydride, and using the heat of reaction to increase the temperature inside the reaction tank and create a high-pressure state, thereby increasing the production rate of calcium oxide from calcium carbonate; a second reaction step of generating sodium carbonate and hydrogen from the sodium bicarbonate and sodium hydride under high-temperature and high-pressure conditions by iron as a catalyst; and a discharge step of discharging the generated calcium oxide, hydrogen, and sodium carbonate from the reaction tank via respective discharge paths.

[0010] The present invention also provides a calcium oxide generating device for generating calcium oxide from calcium carbonate, the device comprising a reaction tank made of a pressure vessel for chemically reacting input raw materials, an input path for inputting various raw materials into the reaction tank, a discharge path for discharging various products generated by the chemical reaction from the reaction tank, and an auxiliary heater, the input paths comprising a calcium carbonate input path, a water input path, a sodium input path, and a catalyst input path, each of which is connected to the reaction tank at one end, the discharge paths comprising a calcium oxide discharge path, a hydrogen discharge path, and a sodium carbonate discharge path, each of which is connected to the reaction tank at one end, and the reaction tank is charged with calcium carbonate, water, and the catalyst. Iron is added, the inside of the reaction tank is heated by an auxiliary heater, sodium is added, and carbon dioxide generated when calcium oxide is produced from calcium carbonate reacts with the added water and sodium to produce sodium bicarbonate and sodium hydride, and the inside of the reaction tank is placed in a high-temperature and high-pressure state. Under this high-temperature and high-pressure state, calcium oxide and carbon dioxide are produced from calcium carbonate, the reaction between carbon dioxide, water and sodium progresses, and hydrogen and sodium carbonate are produced by a chemical reaction between the produced sodium bicarbonate and sodium hydride via the added catalyst, and the produced calcium oxide, hydrogen and sodium carbonate are finally discharged from each discharge route. [Effects of the Invention]

[0011] According to the calcium oxide production method and production device of the present invention, by reacting carbon dioxide generated in the reaction tank during calcium oxide production with water and sodium, it is possible to significantly increase the temperature and pressure in the reaction tank, which contributes to reducing the thermal energy required to produce calcium oxide and accelerating thermal decomposition, and also contributes to reducing the amount of carbon dioxide emitted during calcium oxide production, as the carbon dioxide generated during thermal decomposition is used as a material for the chemical reaction.

[0012] Furthermore, according to the calcium oxide production method and production device of the present invention, sodium carbonate and hydrogen are produced as by-products of calcium oxide production, and the sodium carbonate can be used in a wide range of applications, such as as a raw material for optical glass, a raw material for pharmaceuticals, a coolant, a desiccant, a cleaning agent, and a food additive, and the hydrogen can also be used in a variety of applications, such as as a gaseous fuel for fuel cells and the like, for producing chemical substances such as ammonia and methanol, and for use in medicine as a gas with antioxidant properties, thereby achieving the excellent effect of being usable. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing an embodiment of a calcium oxide generating device according to the present invention. [Figure 2] 1 is a flow chart showing an embodiment of a calcium oxide producing method according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The calcium oxide generating device and method according to the present invention are characterized in that carbon dioxide is decomposed in a reaction tank in which calcium carbonate is calcined by introducing carbon dioxide, water, sodium, and a catalyst, and in addition to calcium oxide, hydrogen and sodium carbonate are generated in the reaction tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a calcium oxide producing apparatus and a calcium oxide producing method according to the present invention will be described with reference to the drawings.

[0015] The overall configuration and the configuration of each part of the calcium oxide generating device and generating method according to the present invention are not limited to the embodiments described below, but can be modified as appropriate within the scope of the technical concept of the present invention, i.e., within the scope of configurations that can achieve the same functional effects.

[0016] Fig. 1 is a block diagram showing an embodiment of a calcium oxide producing apparatus 1 according to the present invention, and Fig. 2 is a flow chart showing an embodiment of a calcium oxide producing method according to the present invention. The calcium oxide generator 1 according to the present invention is mainly composed of a reaction tank 10 in which raw materials are chemically reacted, input paths 21 to 24 through which various raw materials are input into the reaction tank 10, and discharge paths 31 to 34 through which various products generated by the chemical reaction are discharged from the reaction tank 10.

[0017] The reaction vessel 10 (hereinafter sometimes simply referred to as the "vessel") is a pressure vessel having a hollow portion 11, and is a hollow housing to which input paths 21-24 and discharge paths 31-34 are respectively connected. In the hollow portion 11 of the reaction vessel 10, the thermal decomposition of calcium carbonate (Equation 1), the primary chemical reaction of carbon dioxide, water, and sodium (Equation 2), and the secondary chemical reaction of sodium bicarbonate, sodium hydride, and an iron-based catalyst (Equation 3) all take place. There are no particular restrictions on the material of the reaction tank 10, but it is preferable to use a heat-resistant and pressure-resistant material such as nickel or cobalt in order to withstand the high temperature (approximately 1450°C) caused by the mixing of heating (950°C) by the auxiliary heating section 16 described below and the heat (400 to 500°C) generated by the primary chemical reaction, as well as the high pressure (approximately 600 MPa) generated by the primary chemical reaction.

[0018]

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[0019]

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[0020]

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[0021] In the reaction tank 10, a temporary chemical reaction is carried out in which carbon dioxide generated in the reaction tank during calcium oxide production reacts with water and sodium, making it possible to significantly increase the temperature and pressure inside the reaction tank 10, which helps reduce the thermal energy required to produce calcium oxide and promotes thermal decomposition.In addition, since the carbon dioxide generated during thermal decomposition is used as a material for the chemical reaction, it also contributes to reducing the amount of carbon dioxide emitted during calcium oxide production. Furthermore, as by-products of calcium oxide production in the reaction vessel 10, sodium carbonate and hydrogen are produced by a secondary chemical reaction. The sodium carbonate can be used for a wide range of purposes, such as as a raw material for optical glass or pharmaceuticals, as a coolant, a desiccant, a cleaning agent, or a food additive. The hydrogen can also be used for a variety of purposes, such as as a gaseous fuel for fuel cells or the like, for producing chemical substances such as ammonia or methanol, or as a gas with antioxidant properties for medical use.

[0022] The outer shape of the reaction tank 10 is not particularly limited, and may be, for example, a rectangular parallelepiped, or may be an approximately cylindrical or polygonal tubular shape in consideration of pressure resistance. In this case, calcium oxide, the main product, and sodium carbonate, which is generated as a by-product, are sand-like and therefore settle and accumulate downward within the reaction tank. In consideration of efficient discharge of the sodium carbonate, it is preferable that the shape of the lower region of the reaction tank 10 be an inclined shape such as a curved or funnel-shaped shape.

[0023] The reaction vessel 10 is provided with an auxiliary heating section 16 that provides the heat necessary for the thermal decomposition of calcium carbonate. The auxiliary heating unit 16 heats the inside of the reaction tank 10 up to 950°C to promote the thermal decomposition of calcium carbonate introduced into the reaction tank 10. The heating means in the auxiliary heating unit 16 is not particularly limited, and any conventional means may be used. Thus, the provision of the auxiliary heating unit 16 makes it possible to raise the temperature inside the hollow portion 11 to a temperature range suitable for the thermal decomposition of calcium carbonate before a temporary chemical reaction occurs, thereby contributing to the stable production of calcium oxide. The auxiliary heating unit 16 may be operated manually or may be automatically operated after a specified amount (amount determined in consideration of the amount of calcium oxide to be produced) of calcium carbonate, water, and catalyst is added to the reaction tank 10.

[0024] A preferable embodiment is one in which the reaction vessel 10 is provided with a thermometer 13 capable of measuring the temperature of the hollow portion 11. By providing the thermometer 13, it is possible to measure the heating temperature by the auxiliary heating unit 16 and the temperature of the heat of reaction generated in the primary chemical reaction occurring in the hollow portion 11. The level of such a temperature can be used as an indicator for increasing or decreasing the amounts of water and sodium to be introduced, thereby facilitating the adjustment of the amount of chemical reaction.

[0025] In addition, a suitable embodiment is one in which the reaction vessel 10 is provided with a temperature adjustment unit 12 capable of heating and cooling the inside of the hollow portion 11. That is, the temperature adjustment unit 12 heats, cools, and equalizes the temperature in the entire hollow portion 11, depending on the level or unevenness of the heat of reaction generated in the primary chemical reaction, so that the temperature reaches the temperature (at least 825°C or higher) required for calcium oxide production throughout the hollow portion 11. The heating and cooling means in the temperature adjustment unit 12 are not particularly limited, and conventional means may be employed. In this way, the provision of the temperature adjustment unit 12 makes it possible to always maintain an optimal temperature range within the hollow portion 11, contributing to the stable production of calcium oxide. The temperature adjusting unit 12 may be operated manually or may be automatically operated in response to the detected temperature inside the hollow portion 11 .

[0026] Furthermore, a mode in which a pressure gauge 14 is provided in the reaction vessel 10 can be considered. In this mode, the pressure inside the hollow portion 11 generated by the primary chemical reaction is quantified, making it possible to confirm whether the pressure required for the secondary chemical reaction is being generated, and also making it possible to adjust the amount of chemical reaction in the primary chemical reaction by increasing or decreasing the amount of sodium input according to the pressure indicated by the pressure gauge 14 so that the discharge pressure of hydrogen discharged from the reaction vessel 10 through the hydrogen discharge path 31 does not become excessive.

[0027] Furthermore, a carbon dioxide concentration meter 15 may be provided in the reaction tank 10. In this case, the concentration of carbon dioxide in the hollow portion 11 generated by the thermal decomposition of calcium carbonate is quantified, making it possible to confirm the amount of carbon dioxide used in the primary chemical reaction, and also to adjust the amount of chemical reaction in the primary chemical reaction by increasing or decreasing the amount of sodium to be added according to the concentration indicated by the carbon dioxide concentration meter 15.

[0028] The feeding paths are composed of a calcium carbonate feeding path 21, a water feeding path 22, a sodium feeding path 23, and a catalyst feeding path 24, each of which has a hollow tube structure with a predetermined length and required diameter width. One end of each input path is connected to the reaction vessel 10, and various raw materials sent from the other end are circulated and input into the hollow portion 11. The predetermined length of each input path is the piping distance from the tank containing the respective input material to the connection with the reaction vessel 10, and is determined by the installation of each tank. There are no particular limitations on the material of each input path, but since it is expected that the connection between the reaction vessel 10 and each input path will become high temperature and high pressure due to the reaction heat generated in the hollow portion 1, it is possible to use a heat insulating material at least for the connection portion, or to mold each input path entirely from a heat-resistant material.

[0029] The calcium carbonate introduction path 21 is connected to the reaction tank 10 on one side and to the calcium carbonate tank 21A on the other side, and allows calcium carbonate discharged from the calcium carbonate tank 21A to flow through and introduce the calcium carbonate into the hollow portion 11 of the reaction tank 10. The calcium carbonate introduced into the reaction tank 10 is preferably in the form of solid particles, which makes it easy to fine-tune the amount of calcium carbonate introduced into the reaction tank 10. The calcium carbonate tank 21A is preferably disposed near the top of the reaction tank 10 so that calcium carbonate can be introduced into the reaction tank 10 by gravity. In addition, a supply valve 21a that can be opened or closed manually or automatically is preferably provided at a predetermined intermediate position in the calcium carbonate introduction path 21. By adjusting or stopping the introduction of calcium carbonate using the supply valve 21a, it becomes possible to increase or decrease the amounts of calcium oxide and carbon dioxide generated by thermal decomposition or to stop the thermal decomposition.

[0030] One end of the water introduction path 22 is connected to the reaction tank 10, and the other end is connected to a water tank 22A filled with water, and the water discharged from the water tank 22A is circulated through the path 22 to introduce water into the hollow portion 11 of the reaction tank 10. Preferably, the water tank 22A is disposed near the top of the reaction tank 10 so that water can be introduced into the reaction tank 10 by gravity. In addition, it is preferable that a supply valve 22a that can be opened or closed manually or automatically is provided at a predetermined intermediate position in the water introduction path 22. By adjusting or stopping the amount of water introduced by the supply valve 22a, it is possible to increase or decrease the amount of primary chemical reaction in the hollow portion 11 or to stop the reaction.

[0031] The sodium introduction path 23 is connected at one end to the reaction vessel 10 and at the other end to a sodium tank 23A filled with sodium, and allows sodium discharged from the sodium tank 23A to flow through and introduce the sodium into the hollow portion 11 of the reaction vessel 10. The sodium introduced into the reaction vessel 10 is preferably in the form of solid particles, which makes it easy to fine-tune the amount of sodium introduced into the reaction vessel 10. The sodium tank 23A is preferably disposed near the top of the reaction vessel 10 so that sodium can be introduced into the reaction vessel 10 by gravity. In addition, a supply valve 23a that can be opened or closed manually or automatically is preferably provided at a predetermined intermediate position in the sodium introduction path 23. By adjusting or stopping the amount of sodium introduced by the supply valve 23a, it is possible to increase or decrease the amount of primary chemical reaction in the hollow portion 11 or to stop the reaction.

[0032] The catalyst introduction path 24 is connected to the reaction vessel 10 on one side and to a catalyst tank 24A filled with catalyst on the other side, and allows the catalyst discharged from the catalyst tank 24A to flow through and introduce the catalyst into the hollow portion 11 of the reaction vessel 10. The catalyst used in the present invention is not particularly limited, but examples include an iron-based catalyst shown in Equation 4 below, a ruthenium catalyst, and a nickel-lanthanum nitride catalyst (Ni / LaN). Since it is necessary to separate the catalyst from the generated calcium oxide and sodium carbonate when the catalyst is discharged from the reaction vessel 10, a magnetic material such as iron or nickel can be used as the catalyst. By adopting such an embodiment, it becomes easy to separate the magnetic catalyst using a magnet when the catalyst is discharged. In addition, it is preferable that a supply valve 24a that can be opened or closed manually or automatically is provided at a predetermined intermediate position in the catalyst introduction path 24. By adjusting or stopping the amount of catalyst introduced by the supply valve 24a, it is possible to increase or decrease the amount of secondary chemical reaction in the hollow portion 11 or to stop the reaction.

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[0034] The discharge path is composed of a hydrogen discharge path 31, a sodium carbonate discharge path 32, and a calcium oxide discharge path, each of which has a hollow tube structure with a predetermined length and required diameter. One end of each discharge path is connected to the reaction vessel 10, and the product generated in the hollow portion 11 is circulated and sent to the other end. The predetermined length of each discharge path is the piping distance from the reaction vessel 10 containing the respective discharged product to the discharge destination or storage tank. The material of each discharge path is not particularly limited, but since it is expected that the connection parts between the reaction vessel 10 and each discharge path will become high temperature and high pressure due to the reaction heat generated in the hollow portion 11, it is conceivable to use a heat insulating material at least for the connection parts, or to mold each discharge path entirely from a heat-resistant material.

[0035] The hydrogen discharge path 31 is connected to the reaction vessel 10 on one side and to the hydrogen tank 31A on the other side. The hydrogen generated in the hollow portion 11 of the reaction vessel 10 is discharged and sent to the hydrogen tank 31A for filling and storage. Since the generated hydrogen is gaseous and lighter than air, the hydrogen discharge path 31 is preferably connected to a predetermined location at the top of the reaction vessel 10. Also, the hydrogen discharge path 31 is preferably provided with a discharge valve 31a at a predetermined intermediate location that can be opened or closed manually or automatically. The discharge valve 31a can be used to adjust or stop the amount of hydrogen discharged, thereby increasing, decreasing, or stopping the amount of hydrogen discharged to the hydrogen tank 31A.

[0036] Incidentally, the hydrogen produced in the hollow portion 11 of the reaction vessel 10 is discharged into the hydrogen discharge path 31 under ultra-high pressure, and if the hydrogen tank 31A is filled with the hydrogen while still in the ultra-high pressure state, this could cause gas leaks and even an explosion. Therefore, it is preferable to provide a pressure reducing valve 31b at a predetermined intermediate position in the hydrogen discharge path 31, which makes it possible to reduce the pressure of the hydrogen discharged from the hollow portion 11 before sending it to the hydrogen tank 31A. The pressure reducing valve 31b is provided in the hydrogen discharge path 31 midway between the hydrogen discharge valve 31a and the hydrogen tank 31A.

[0037] When filling the hydrogen tank 31A with the generated hydrogen, it is also preferable to cool the hydrogen and then fill and store it as liquefied hydrogen, rather than filling and storing high-pressure gaseous hydrogen in the hydrogen tank 31A as is. Liquefaction contributes to increased storage capacity and ease of handling. Such liquefied hydrogen can be generated in the hydrogen tank 31A. Alternatively, a storage tank for liquefied hydrogen can be installed downstream of the hydrogen tank 31A, and gaseous ammonia can be cooled and liquefied in the storage tank. While hydrogen liquefies at −253°C under atmospheric pressure, the hydrogen delivered to the hydrogen tank 31A is already in a high-pressure state, so the cooling temperature for liquefaction does not need to be that low. The hydrogen cooling method is not particularly limited; a conventional method, such as a hydrogen liquefier, can be used.

[0038] One end of the sodium carbonate discharge path 32 is connected to the reaction tank 10, thereby discharging sodium carbonate produced in the hollow portion 11 of the reaction tank 10 to the outside of the tank. Since the produced sodium carbonate is sand-like and accumulates in the lower part of the reaction tank 10, it is preferable that the sodium carbonate discharge path 32 be connected to a predetermined position at the lower part of the reaction tank 10. In addition, a preferred embodiment is one in which a discharge valve 32a that can be opened or closed manually or automatically is provided at a predetermined intermediate position in the sodium carbonate discharge path 32. The discharge valve 32a makes it possible to adjust or stop the amount of sodium carbonate being discharged.

[0039] One end of calcium oxide discharge path 34 is connected to reaction tank 10, thereby discharging calcium oxide produced in hollow portion 11 of reaction tank 10 to the outside of the tank. Note that, since the produced calcium oxide is also sand-like like sodium carbonate and accumulates at the bottom of reaction tank 10, it is preferable that calcium oxide discharge path 34 be connected to a predetermined location at the bottom of reaction tank 10. In addition, a preferred embodiment is one in which a discharge valve 34a that can be opened or closed manually or automatically is provided at a predetermined intermediate position in the calcium carbonate discharge path 34. The discharge valve 34a makes it possible to adjust or stop the amount of calcium oxide being discharged.

[0040] The calcium oxide and sodium carbonate produced in the reaction tank 10 are sand-like in shape and are deposited by gravity at the bottom of the reaction tank 10. For this reason, although not shown, a preferred embodiment is one in which an outlet and an outlet pipe for the sodium carbonate discharge path 32 and the calcium oxide discharge path 34 are provided in the same location at the bottom of the reaction tank 10, particularly near the bottom, with a funnel-like slope. When such an embodiment is adopted, the material discharged from the outlet is a mixture of calcium oxide and calcium carbonate, mixed together with the excess catalyst after the reaction that has deposited at the bottom of the reaction tank 10. The mixture discharged from the outlet passes through a separator disposed at a predetermined intermediate point of the discharge pipe, where calcium oxide, sodium carbonate, and catalyst are separated and discharged. The separator may be constructed using conventionally known technology, for example, a separator using a separation structure that utilizes differences in specific gravity (sodium carbonate 2.532, calcium oxide 3.3, iron 7.86). The calcium oxide and sodium carbonate separated by the separation device are used for their respective purposes, and the catalyst is returned to the catalyst tank 24A and reused as a catalyst.

[0041] As shown in FIG. 1, the reaction vessel 10 may also be provided with an excess gas exhaust path 33 in addition to the hydrogen exhaust path 31, the sodium carbonate exhaust path 32, and the calcium oxide exhaust path 34. The excess gas exhaust path 33 is used to exhaust excess gases not consumed in the secondary chemical reaction, particularly carbon dioxide and ozone, which are expected to be excess gases. Of these excess gases, it is preferable that carbon dioxide be reused to adjust the concentration of carbon dioxide used in the temporary chemical reaction, while ozone be released directly into the atmosphere. The excess gas exhaust path 33 is provided with a discharge valve 33a at a predetermined intermediate position that can be opened or closed manually or automatically.

[0042] The calcium oxide generator 1 according to the present invention is made up of the above-mentioned components. That is, the calcium oxide generator 1 is made up of a reaction tank 10 in which raw materials are chemically reacted, input routes connected to the reaction tank 10, including a calcium carbonate input route 21 for inputting calcium carbonate, a water input route 22 for inputting water, a sodium input route 23 for inputting sodium, and a catalyst input route 24 for inputting a catalyst, and discharge routes connected to the reaction tank 10, including a hydrogen discharge route 31 for discharging hydrogen, a sodium carbonate discharge route 32 for discharging sodium carbonate, and a calcium oxide discharge route 34 for discharging calcium oxide.

[0043] The calcium oxide producing method according to the present invention is realized by the calcium oxide producing apparatus 1, and mainly includes a calcium carbonate introducing step C1 (hereinafter, sometimes simply referred to as "introducing step C1") in which calcium carbonate, water, and a catalyst as raw materials are introduced into the reaction vessel 10 through the introduction paths 21, 22, and 24, an auxiliary heating step C2 in which the inside of the reaction vessel 10 is heated to 950°C by the auxiliary heating unit 16, and a step C3 in which sodium is introduced into the reaction vessel 10 through the introduction path 23, and carbon dioxide generated by the thermal decomposition of calcium carbonate is produced by a chemical reaction between the introduced sodium and the water. The process comprises a first reaction step C3 in which sodium bicarbonate and sodium hydride are generated, and the heat of reaction used to raise the temperature and create a high-pressure state in the reaction tank 10, thereby increasing the rate at which calcium oxide is generated from calcium carbonate; a second reaction step C4 in which sodium carbonate and hydrogen are generated from sodium bicarbonate and sodium hydride using iron as a catalyst in the high-temperature, high-pressure environment in the reaction tank 10; and a discharge step C5 in which the generated calcium oxide, sodium carbonate, and hydrogen are discharged from the reaction tank 10 via discharge paths 32 to 34.

[0044] The method for producing calcium oxide according to the present invention will be described in detail below. The calcium carbonate feeding step C1 is a step of feeding raw materials into the reaction tank 10 through the respective feeding paths 21, 22, and 24. Calcium carbonate delivered from a calcium carbonate tank 21A is fed into the reaction tank 10 through the calcium carbonate feeding path 21, water stored in a water tank 22A is fed through the water feeding path 22, and a catalyst stored in a catalyst tank 24A is fed through the catalyst feeding path 24. The amounts of the raw materials fed are the amounts required for the chemical reaction in the reaction tank 10, and expressed in molecular weight, the amounts expressed by Equation 2, which are based on the amount of calcium oxide produced by Equation 1 and the amount of carbon dioxide produced simultaneously. The amounts of the raw materials fed are adjusted by the respective supply valves 21a, 22a, and 24a.

[0045] The auxiliary heating step C2 is a step in which the inside of the reaction tank 10 is heated to 950°C by the auxiliary heating unit 16. By heating the calcium carbonate introduced into the reaction tank 10, part of the calcium carbonate is decomposed into calcium oxide and carbon dioxide as shown in the above equation 1. At the same time, water introduced into the reaction tank 10 also turns into superheated steam due to the temperature change in the reaction tank 10, thereby increasing the pressure inside the reaction tank 10.

[0046] The first reaction step C3 is a step in which sodium is introduced into the reaction vessel 10 through the introduction path 23, and the carbon dioxide produced in the previous auxiliary heating step C2 is temporarily chemically reacted with the water introduced in the introduction step C1, and the chemical reaction between sodium, carbon dioxide, and water produces sodium bicarbonate and sodium hydride as shown in the above equation 2. This chemical reaction is accompanied by the sudden generation of high heat and pressure, and as a result, the inside of the reaction vessel 10 becomes a high-temperature and high-pressure state, which promotes the thermal decomposition of calcium carbonate that remains undecomposed in the reaction vessel 10 and increases the rate of calcium oxide production.

[0047] The second reaction step C4 is a step of carrying out a secondary chemical reaction between the sodium bicarbonate and sodium hydride produced in the first reaction step C3 in the reaction vessel 10. The sodium bicarbonate and sodium hydride are chemically reacted via the catalyst introduced in the introduction step C1, producing hydrogen and sodium carbonate, as shown in Equation 3. This chemical reaction between sodium bicarbonate and sodium hydride requires not only a catalyst but also high heat (approximately 400 to 600°C) and high pressure (20 to 100 MPa). However, because the reaction vessel 10 is already at a high temperature and pressure due to the heating by the auxiliary heating unit 16 in the auxiliary heating step C2 and the primary chemical reaction in the first reaction step C3, additional heating or pressurization is not required in this step. However, it is anticipated that the required temperature may not be obtained in the reaction vessel 10 due to an incomplete reaction in the first reaction step C3, etc. In such cases, the temperature is appropriately adjusted using the temperature adjustment unit 12 provided in the reaction vessel 10 to maintain the appropriate temperature in the reaction vessel 10.

[0048] The discharge step C5 is a step of discharging products from the reaction tank 10 via each discharge path, in which calcium oxide produced from the auxiliary heating step C2 to the first reaction step C3 is discharged to the outside of the tank via the calcium oxide discharge path 34, and sodium carbonate produced in the second reaction step C4 is also discharged to the outside of the tank via the sodium carbonate discharge path 32. Then, the hydrogen produced in the second reaction step C4 is discharged to the hydrogen tank 31A via the hydrogen discharge path 31. At this time, the hydrogen produced in the reaction vessel 10 is in an ultra-high pressure state, so it is appropriately depressurized by the pressure reducing valve 31b provided in the hydrogen discharge line 31, and sent to the hydrogen tank 31A at an appropriate pressure. Furthermore, when calcium oxide is discharged from calcium oxide discharge path 34 and sodium carbonate is discharged from sodium carbonate discharge path 32, excess catalyst accumulated at the bottom of reaction tank 10 is also discharged together, but a separator is inserted to separate calcium oxide, sodium carbonate, and catalyst, and the separated catalyst is returned to catalyst tank 24A for reuse.

[0049] As described above, according to the calcium oxide generating apparatus and method of the present invention, calcium carbonate, water, and a catalyst are introduced into the reaction vessel 10, and the inside of the reaction vessel 10 is heated to thermally decompose part of the calcium carbonate to generate calcium oxide, and sodium bicarbonate and sodium hydride are generated through a primary chemical reaction between the carbon dioxide generated during the thermal decomposition, the water, and sodium added after the reaction vessel 10 is heated. At the same time, the temperature and pressure inside the reaction vessel 10 are increased to promote the thermal decomposition of calcium carbonate, thereby facilitating the generation of calcium oxide. In addition, hydrogen and sodium carbonate can be generated by a secondary chemical reaction between the iron-based catalyst, the sodium bicarbonate generated in the primary chemical reaction, and sodium hydride in an atmosphere sufficiently satisfied with the temperature and pressure required for hydrogen generation. [Industrial Applicability]

[0050] The calcium oxide generating device and method according to the present invention provide a new method for generating calcium oxide, and at the same time, it is a technology that contributes to reducing emissions into the atmosphere by utilizing carbon dioxide, a greenhouse gas generated during the thermal decomposition of calcium carbonate, as a material in a chemical reaction that is effective in increasing the temperature and pressure inside the tank, and is therefore believed to have extremely great industrial applicability. [Explanation of symbols]

[0051] 1. Calcium oxide generator 10 Reaction vessel 11 Hollow part 12 Temperature adjustment section 13 Thermometer 14 Pressure gauge 15 Carbon dioxide concentration meter 16 Auxiliary heating section 21 Calcium carbonate injection route 21A Calcium Carbonate Tank 21a Supply valve 22 Water input route 22A Water Tank 22a Supply valve 23 Sodium input pathway 23A Sodium Tank 23a Supply valve 24 Catalyst injection route 24A Catalyst Tank 24a Supply valve 31 Hydrogen Emission Pathways 31A Hydrogen Tank 31a Discharge valve 31b Pressure reducing valve 32 Sodium carbonate excretion pathway 32a Discharge valve 33 Excess gas exhaust route 33a Discharge valve 34 Calcium oxide excretion pathway 34a Discharge valve C0 Calcium oxide production process C1 Calcium oxide injection process C2 Auxiliary heating process C3 First reaction step C4 Second Response Project C5 discharge process

Claims

1. A method for producing calcium oxide from calcium carbonate, comprising the steps of: a calcium oxide introduction step of introducing calcium carbonate, water, and iron as a catalyst into a reaction tank made of a pressure vessel; an auxiliary heating step of raising the temperature inside the reaction vessel to 950°C; a first reaction step in which sodium is introduced into the vessel, and carbon dioxide generated during the production of calcium oxide from calcium carbonate reacts with water and sodium to generate sodium bicarbonate and sodium hydride, and the heat of reaction used to raise the temperature inside the reaction vessel, creating a high-pressure state and increasing the rate at which calcium oxide is produced from calcium carbonate; A second reaction step in which sodium carbonate and hydrogen are produced from sodium bicarbonate and sodium hydride under high temperature and pressure conditions using iron as a catalyst. a discharge step of discharging the produced calcium oxide, hydrogen, and sodium carbonate from the reaction tank through respective discharge paths; A method for producing calcium oxide comprising the steps of:

2. A calcium oxide generating apparatus for generating calcium oxide from calcium carbonate, The system comprises a reaction tank formed of a pressure vessel in which input raw materials are subjected to a chemical reaction, an input path for inputting various raw materials into the reaction tank, a discharge path for discharging various products generated by the chemical reaction from the reaction tank, and an auxiliary heater; The feeding paths are composed of a calcium carbonate feeding path, a water feeding path, a sodium feeding path, and a catalyst feeding path, One end of each of the input paths is connected to a reaction vessel, The discharge path is composed of a calcium oxide discharge path, a hydrogen discharge path, and a sodium carbonate discharge path, One end of each discharge path is connected to a reaction tank, Calcium carbonate, water, and iron as a catalyst are added to the reaction tank. The auxiliary heater heats the inside of the reaction vessel. Add sodium, Sodium hydrogen carbonate and sodium hydride are produced by a chemical reaction between carbon dioxide, which is generated when calcium oxide is produced from calcium carbonate, the added water, and sodium. At the same time, the inside of the reaction tank becomes a high-temperature and high-pressure state. Under such high temperature and pressure conditions, calcium oxide and carbon dioxide are produced from calcium carbonate, The reaction between carbon dioxide, water and sodium progresses, Hydrogen and sodium carbonate are produced by a chemical reaction between the sodium bicarbonate produced through the catalyst and sodium hydride. A calcium oxide generating apparatus characterized in that the calcium oxide, hydrogen, and sodium carbonate finally generated are discharged from each discharge path.

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