Calcium Oxide Production Apparatus and Production Method

Abstract

Provided are 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 mainly composed of iron in a reaction vessel used for firing calcium carbonate. 【Solution means】A calcium oxide production apparatus for producing calcium oxide from calcium carbonate, comprising a reaction vessel, an input path, an output path, and an auxiliary heater. Calcium carbonate, water, and iron as a catalyst are input into the reaction vessel, the inside of the reaction vessel is heated by the auxiliary heater, and then sodium is input. Calcium oxide, hydrogen, and sodium carbonate finally produced by the chemical reaction are discharged from each output path.

Description

Technical Field

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

Background Art

[0002] Conventionally, quicklime (calcium oxide) has been widely used in various industries such as mortar used in construction and pH adjusters for acidic soil. In the process of producing such calcium oxide, it is known that when calcium carbonate is calcined, carbon dioxide is generated simultaneously with the production of calcium oxide, and many methods for reducing or adsorbing the generated carbon dioxide have been published.

[0003] However, when the above methods are used, there are many cases where the equipment becomes large-scale, such as multiple tanks being required for the production of calcium oxide, or the production efficiency of calcium oxide decreases, and it has not been a fundamental solution. Therefore, there has been a demand for a production method that suppresses the release of carbon dioxide during the production of calcium oxide in one tank.

[0004] In order to solve the above problems, a technical proposal described in Japanese Patent Application Laid-Open No. 2022-96876 (Patent Document 1) has been proposed. Specifically, it is a technical proposal for reacting carbon dioxide gas and hydrogen gas using a limestone firing furnace and a catalyst to produce methane.

[0005] However, in the technical proposal described in Patent Document 1, it is necessary to install a methane production device for reacting a carbon dioxide-containing gas and hydrogen separately from the firing furnace, and the problem has not been solved.

[0006] Therefore, the applicant of the present application focused on the carbon dioxide generated during the production of calcium oxide, and under the idea of whether it is possible to decompose the carbon dioxide generated in the pressure vessel to reduce the emission amount into the atmosphere, the carbon dioxide generated during the calcination of calcium carbonate is made to chemically react with water and sodium to generate sodium carbonate and hydrogen in the pressure vessel together with the production of calcium oxide, and thus developed a method and an apparatus, leading to the proposal of the "calcium oxide production apparatus and production method" in the present invention.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] In view of the above problems, the present invention aims to provide an apparatus and a method for producing calcium oxide with reduced carbon dioxide emissions by means of a chemical reaction between carbon dioxide, water, sodium, and a catalyst mainly composed of iron in a reaction vessel used for the calcination of calcium carbonate.

Means for Solving the Problems

[0009] To solve the above problems, the present invention provides a method for producing calcium oxide from calcium carbonate, comprising: a calcium carbonate charging step of charging calcium carbonate, water, and iron as a catalyst into a reaction tank composed of a pressure vessel; an auxiliary heating step of raising the temperature in the reaction tank to 950°C; a first reaction step of charging sodium into the vessel, generating sodium hydrogen carbonate and sodium hydride by the reaction of carbon dioxide, water, and sodium generated when producing calcium oxide from calcium carbonate, raising the temperature in the reaction tank by the reaction heat at that time to a high-pressure state, and increasing the production rate of calcium oxide from calcium carbonate; a second reaction step of generating sodium carbonate and hydrogen from sodium hydrogen carbonate and sodium hydride by iron as a catalyst at a high temperature and high pressure; and a discharging step of discharging the generated calcium oxide, hydrogen, and sodium carbonate from the reaction tank through respective discharge paths.

[0010] The present invention also relates to a calcium oxide production apparatus for producing calcium oxide from calcium carbonate, which comprises a reaction tank composed of a pressure vessel for chemically reacting the 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 path is composed of a calcium carbonate input path, a water input path, a sodium input path, and a catalyst input path. One end of each input path is connected to the reaction tank respectively. 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 the reaction tank respectively. Calcium carbonate, water, and iron as a catalyst are input into the reaction tank, the inside of the reaction tank is heated by the auxiliary heater, sodium is input, and sodium hydrogen carbonate and sodium hydride are generated by the chemical reaction of carbon dioxide generated when producing calcium oxide from calcium carbonate, the input water, and sodium. At the same time, the inside of the reaction tank becomes a high-temperature and high-pressure state. Under such a high-temperature and high-pressure state, calcium oxide and carbon dioxide are generated from calcium carbonate, the reaction of carbon dioxide, water, and sodium proceeds, and hydrogen and sodium carbonate are generated by the chemical reaction of sodium hydrogen carbonate and sodium hydride generated through the input catalyst. Finally, the produced calcium oxide, hydrogen, and sodium carbonate are discharged from each discharge path.

Advantages of the Invention

[0011] According to the calcium oxide production method and production apparatus of the present invention, by reacting carbon dioxide, water, and sodium generated in the reaction tank during the production of calcium oxide, it is possible to greatly increase the temperature and pressure in the reaction tank, contribute to the reduction of thermal energy required for the production of calcium oxide and the promotion of thermal decomposition, and use carbon dioxide generated during thermal decomposition as a material for chemical reaction, thus contributing to the reduction of the carbon dioxide emission amount associated with the production of calcium oxide.

[0012] Moreover, according to the calcium oxide production method and production apparatus of the present invention, sodium carbonate and hydrogen are produced as by-products of calcium oxide production. The sodium carbonate can be used in a wide range of applications such as raw materials for optical glass, raw materials for pharmaceuticals, coolants, desiccants, detergents, food additives, etc. The hydrogen can also be used in various applications such as the production of chemical substances such as ammonia and methanol in addition to gaseous fuels such as fuel cells, and medical use as a gas having an antioxidant effect, and exhibits excellent effects such as these.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0014] The calcium oxide production apparatus and production method according to the present invention are characterized in that by introducing carbon dioxide, water, sodium, and a catalyst into a reaction vessel for firing calcium carbonate, carbon dioxide is decomposed in the reaction vessel, and in addition to calcium oxide, hydrogen and sodium carbonate are produced. Hereinafter, embodiments of the calcium oxide production apparatus and production method according to the present invention will be described with reference to the drawings.

[0015] Note that the overall configuration and the configuration of each part of the calcium oxide production apparatus and production method according to the present invention are not limited to the embodiments described below, and can be appropriately changed within the scope of the technical idea of the present invention, that is, within the scope of configuration modes that can exhibit the same operational effects.

[0016] FIG. 1 is a block diagram showing an embodiment of a calcium oxide production apparatus 1 according to the present invention. Further, FIG. 2 is a flowchart showing an embodiment of a calcium oxide production method according to the present invention. The calcium oxide production device 1 according to the present invention mainly comprises a reaction tank 10 for chemically reacting raw materials, input paths 21 to 24 for introducing various raw materials into the reaction tank 10, and discharge paths 31 to 34 for discharging various products generated by the chemical reaction from the reaction tank 10.

[0017] The reaction tank 10 (hereinafter sometimes simply referred to as "tank") is a pressure vessel having a hollow portion 11, and is a hollow housing to which the input paths 21 to 24 and the discharge paths 31 to 34 are respectively connected. In the hollow portion 11 of the reaction tank 10, thermal decomposition of calcium carbonate (Equation 1), primary chemical reaction of carbon dioxide, water and sodium (Equation 2), and secondary chemical reaction of sodium bicarbonate, sodium hydride and a catalyst mainly composed of iron (Equation 3) will be respectively carried out. Although the material of the reaction tank 10 is not particularly limited, in order to withstand the heating (950 ° C) by the auxiliary heating unit 16 described later and the high temperature (approximately 1450 ° C) caused by the mixture of the heat generation (400 to 500 ° C) accompanying the primary chemical reaction and the generation of high pressure (about 600 MPa) accompanying the primary chemical reaction, it is preferable to use a heat-resistant and pressure-resistant material such as nickel or cobalt for the tank.

[0018]

Equation

[0019]

Equation

[0020]

Equation

[0021] In the reaction tank 10, by performing a temporary chemical reaction that reacts carbon dioxide, water, and sodium generated in the reaction tank during the production of calcium oxide, it becomes possible to greatly increase the temperature and pressure in the reaction tank 10, contributing to a reduction in the thermal energy required for the production of calcium oxide and the promotion of thermal decomposition. In addition, since carbon dioxide generated during thermal decomposition is used as a material for the chemical reaction, it contributes to reducing the amount of carbon dioxide released during the production of calcium oxide. Also, as by-products during the production of calcium oxide in the reaction tank 10, sodium carbonate and hydrogen are generated by a secondary chemical reaction. The sodium carbonate can be used in a wide range of applications such as raw materials for optical glass, raw materials for pharmaceuticals, coolants, desiccants, detergents, food additives, etc. The hydrogen can also be used in various applications such as the production of chemical substances such as ammonia and methanol in addition to gaseous fuels such as fuel cells, and as a gas with antioxidant properties for medical use, etc., showing excellent effects.

[0022] The outer shape of the reaction tank 10 is not particularly limited. For example, in addition to a rectangular parallelepiped, a substantially cylindrical shape or a substantially polygonal cylindrical shape can be considered in view of pressure resistance. At this time, since the main product calcium oxide and the sodium carbonate generated as a by-product are in a sandy state, they will settle and accumulate downward in the reaction tank. In view of improving the efficiency of discharging the sodium carbonate, the shape of the lower region of the reaction tank 10 is preferably a shape with an inclination such as a curved surface or a funnel shape.

[0023] The reaction tank 10 is provided with an auxiliary heating unit 16 that provides the heat required for the thermal decomposition of calcium carbonate. The auxiliary heating unit 16 heats the inside of the reaction tank 10 up to 950 °C and promotes the thermal decomposition of the calcium carbonate introduced into the reaction tank 10. The heating means in such an auxiliary heating unit 16 is not particularly limited, and conventional means can be adopted. Thus, by providing the auxiliary heating unit 16, it becomes possible to raise the temperature in the hollow portion 11 to a temperature range suitable for the thermal decomposition of calcium carbonate before the temporary chemical reaction occurs, contributing to the stable production of calcium oxide. Regarding the operation of such an auxiliary heating unit 16, in addition to the manually operated mode, it can also be set to automatically operate after a specified amount (an amount determined in view of the amount of calcium oxide to be generated) of calcium carbonate, water, and a catalyst are introduced into the reaction tank 10.

[0024] It is preferable that the reaction tank 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 reaction heat generated in the primary chemical reaction occurring in the hollow portion 11. The amount of water and sodium input can be increased or decreased based on the level of such temperature, thereby facilitating the adjustment of the chemical reaction amount.

[0025] Also, it is preferable that the reaction tank 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 performs heating, cooling, and homogenization so that the entire hollow portion 11 reaches the temperature required for the production of calcium oxide (at least 825 °C or higher) according to the level and bias of the reaction heat generated in the primary chemical reaction. There are no particular limitations on the heating and cooling means in such a temperature adjustment unit 12, and conventional means can be employed. Thus, by providing the temperature adjustment unit 12, it becomes possible to always keep the inside of the hollow portion 11 in an optimal temperature range, contributing to the stable production of calcium oxide. Regarding the operation of such a temperature adjustment unit 12, in addition to the manually operated mode, it can also be set to automatically operate according to the detected temperature inside the hollow portion 11.

[0026] Furthermore, it is conceivable that the reaction tank 10 is provided with a pressure gauge 14. In this case, the pressure inside the hollow portion 11 generated by the primary chemical reaction is digitized, enabling confirmation of whether the pressure required for the secondary chemical reaction is generated. Also, the amount of sodium input can be increased or decreased according to the pressure indicated by the pressure gauge 14 so that the discharge pressure of hydrogen discharged from the reaction tank 10 through the hydrogen discharge path 31 does not become excessive, and it is also possible to adjust the chemical reaction amount in the primary chemical reaction.

[0027] Furthermore, it is also conceivable that the reaction tank 10 is equipped with a carbon dioxide concentration meter 15. In this mode, the carbon dioxide concentration in the hollow portion 11 generated by the thermal decomposition of calcium carbonate is digitized, enabling confirmation of the amount of carbon dioxide used in the temporary chemical reaction. Additionally, it is possible to adjust the amount of sodium input according to the concentration indicated by the carbon dioxide amount concentration meter 15 and regulate the amount of chemical reaction in the primary chemical reaction.

[0028] The input paths are composed of a calcium carbonate input path 21, a water input path 22, a sodium input path 23, and a catalyst input path 24, each having a hollow tube structure with a predetermined length and required diameter width. One end of each input path is connected to the reaction tank 10 respectively, allowing various raw materials sent from the other end to flow through and be introduced into the hollow portion 11. The predetermined length in each input path is the piping distance from the tank containing each input substance to the connection part with the reaction tank 10, which is determined by the installation of each tank. Regarding the material of each input path, although it is not particularly limited, since it is assumed that the connection part between the reaction tank 10 and each input path will be at high temperature and high pressure due to the reaction heat generated in the hollow portion 1, it is conceivable to use a heat-insulating material at least for the connection part or to form the entire input path with a heat-resistant material.

[0029] One end of the calcium carbonate input path 21 is connected to the reaction tank 10, and the other end is connected to a calcium carbonate tank 21A. It allows the calcium carbonate discharged from the calcium carbonate tank 21A to flow through and introduces the calcium carbonate into the hollow portion 11 in the reaction tank 10. The calcium carbonate introduced into the reaction tank 10 is preferably in the form of solid particles, which facilitates fine adjustment of the amount of calcium carbonate input into the reaction tank 10. Incidentally, the calcium carbonate tank 21A is preferably arranged near the upper part of the reaction tank 10 so that calcium carbonate can be introduced into the reaction tank 10 according to gravity. In addition, it is preferable that the calcium carbonate input path 21 is provided with a supply valve 21a that opens and closes manually or automatically at a predetermined intermediate position. By adjusting or stopping the input of calcium carbonate with such a supply valve 21a, it becomes possible to increase or decrease the amount of calcium oxide and carbon dioxide generated by thermal decomposition and to stop the thermal decomposition.

[0030] One side of the water input path 22 is connected to the reaction tank 10, and the other side is connected to a water tank 22A filled with water. The water discharged from the water tank 22A is circulated, and water is input into the hollow portion 11 in the reaction tank 10. Incidentally, it is preferable that the water tank 22A is disposed in the vicinity of the upper part of the reaction tank 10 so that water can be input into the reaction tank 10 according to gravity. In addition, it is preferable that the water input path 22 is provided with a supply valve 22a that opens and closes manually or automatically at a predetermined intermediate position. By adjusting or stopping the amount of water input with such a supply valve 22a, it becomes possible to increase or decrease or stop the primary chemical reaction amount in the hollow portion 11.

[0031] One side of the sodium input path 23 is connected to the reaction tank 10, and the other side is connected to a sodium tank 23A filled with sodium. The sodium discharged from the sodium tank 23A is circulated, and sodium is input into the hollow portion 11 in the reaction tank 10. The sodium input into the reaction tank 10 is preferably in the form of solid particles, which facilitates fine adjustment of the amount of sodium input into the reaction tank 10. Incidentally, it is preferable that the sodium tank 23A is disposed in the vicinity of the upper part of the reaction tank 10 so that sodium can be input into the reaction tank 10 according to gravity. In addition, it is preferable that the sodium input path 23 is provided with a supply valve 23a that opens and closes manually or automatically at a predetermined intermediate position. By adjusting or stopping the amount of sodium input with such a supply valve 23a, it becomes possible to increase or decrease or stop the primary chemical reaction amount in the hollow portion 11.

[0032] The catalyst input path 24 has one end connected to the reaction tank 10 and the other end connected to a catalyst tank 24A filled with a catalyst. It allows the catalyst discharged from the catalyst tank 24A to flow through and injects the catalyst into the hollow portion 11 in the reaction tank 10. The catalyst used in the present invention is not particularly limited. For example, a catalyst mainly composed of iron shown in Equation 4 below, a ruthenium catalyst, a nickel / lanthanum nitride catalyst (Ni / LaN), etc. can be used. In addition, when discharging from the reaction tank 10, since it is necessary to separate only the catalyst from the generated calcium oxide and sodium carbonate, a mode of using a magnetic substance such as iron or nickel as the catalyst can be considered. By adopting such a mode, it becomes easy to separate only the catalyst which is a magnetic substance using a magnet at the time of discharge. Also, it is preferable that the catalyst input path 24 is provided with a supply valve 24a that opens and closes manually or automatically at a predetermined intermediate position. By adjusting or stopping the amount of the catalyst to be input by the supply valve 24a, it becomes possible to increase, decrease, or stop the amount of the secondary chemical reaction in the hollow portion 11.

[0033]

Equation

[0034] The discharge paths are composed of a hydrogen discharge path 31, a sodium carbonate discharge path 32, and a calcium oxide discharge path, each having a hollow tube structure with a predetermined length and required diameter width. One end of each discharge path is connected to the reaction tank 10 respectively, allowing the products generated in the hollow portion 11 to flow through and be sent to the other end. Also, the predetermined length in each discharge path is the piping distance from the reaction tank 10 where each discharge product is stored to the discharge destination or the storage tank. Regarding the material of each discharge path, it is not particularly limited. However, since it is assumed that the connection portion between the reaction tank 10 and each discharge path becomes high temperature and high pressure due to the reaction heat generated in the hollow portion 11, a mode of using a heat-insulating material at least for the connection portion or molding the entire discharge path with a heat-resistant material can be considered.

[0035] The hydrogen discharge path 31 is connected to the reaction tank 10 at one end and to the hydrogen tank 31A at the other end. It discharges the hydrogen generated in the hollow portion 11 of the reaction tank 10 and supplies and stores the hydrogen in the hydrogen tank 31A. Since the generated hydrogen is in a gaseous state and lighter than air, it is preferable that the hydrogen discharge path 31 is connected to a predetermined upper portion of the reaction tank 10. Also, it is preferable that the hydrogen discharge path 31 is provided with a discharge valve 31a that opens and closes manually or automatically at a predetermined intermediate position. By adjusting or stopping the amount of hydrogen discharged by such a discharge valve 31a, it is possible to increase, decrease, or stop the amount of hydrogen discharged to the hydrogen tank 31A.

[0036] Incidentally, the hydrogen generated in the hollow portion 11 of the reaction tank 10 is discharged into the hydrogen discharge path 31 in an ultra-high pressure state. If it is filled into the hydrogen tank 31A while remaining in the ultra-high pressure state, gas leakage etc. will be caused and the risk of explosion is also assumed. Therefore, it is preferable to arrange a pressure reducing valve 31b at a predetermined intermediate position of the hydrogen discharge path 31, so that it is possible to reduce the pressure of the hydrogen discharged from the hollow portion 11 and then supply it to the hydrogen tank 31A. Such a pressure reducing valve 31b is arranged between the hydrogen discharge valve 31a and the hydrogen tank 31A in the hydrogen discharge path 31.

[0037] When filling the generated hydrogen into the hydrogen tank 31A, instead of directly filling and storing the high-pressure gaseous hydrogen into the hydrogen tank 31A, it is also preferable to cool it and fill and store it as liquefied hydrogen. Liquefaction contributes to an increase in the storage amount and ease of handling. The generation of such liquefied hydrogen can be carried out not only in the hydrogen tank 31A, but also by arranging a storage tank for liquefied hydrogen downstream of the hydrogen tank 31A and cooling and liquefying gaseous ammonia in the storage tank. Incidentally, hydrogen liquefies at -253°C under atmospheric pressure, but since the hydrogen supplied to the hydrogen tank 31A is already in a high-pressure state, the cooling temperature for liquefaction does not need to be so low. The cooling means for hydrogen is not particularly limited, and conventional means such as a hydrogen liquefier can be used.

[0038] One side of the sodium carbonate discharge path 32 is connected to the reaction tank 10 to discharge the sodium carbonate generated in the hollow portion 11 of the reaction tank 10 to the outside of the tank. Since the generated sodium carbonate is in a sandy form and accumulates at the lower part of the reaction tank 10, it is preferable that the sodium carbonate discharge path 32 is connected to a predetermined lower position in the reaction tank 10. Also, it is preferable that the sodium carbonate discharge path 32 is provided with a discharge valve 32a that opens and closes manually or automatically at a predetermined intermediate position. By means of such a discharge valve 32a, it is possible to adjust and stop the amount of sodium carbonate to be discharged.

[0039] One side of the calcium oxide discharge path 34 is connected to the reaction tank 10 to discharge the calcium oxide generated in the hollow portion 11 of the reaction tank 10 to the outside of the tank. Since the generated calcium oxide is also in a sandy form similar to sodium carbonate and accumulates at the lower part of the reaction tank 10, it is preferable that the calcium oxide discharge path 34 is connected to a predetermined lower position in the reaction tank 10. Also, it is preferable that the calcium carbonate discharge path 34 is provided with a discharge valve 34a that opens and closes manually or automatically at a predetermined intermediate position. By means of such a discharge valve 34a, it is possible to adjust and stop the amount of calcium oxide to be discharged.

[0040] The calcium oxide and sodium carbonate generated in the reaction tank 10 are in a sandy form and accumulate at the lower part of the reaction tank 10 according to gravity. Therefore, although not shown in the figure, it is preferable to provide a discharge port and a discharge pipe with the sodium carbonate discharge path 32 and the calcium oxide discharge path 34 at the same location, with a funnel-shaped inclination near the lower part, particularly the lowermost part, of the reaction tank 10. When adopting such a mode, what is discharged from the discharge port is a mixture in which calcium oxide and calcium carbonate are mixed, and the excess catalyst after the reaction that had accumulated at the lower part of the reaction tank 10 is also mixed together. Then, the mixture discharged from the discharge port is separated and discharged through a separation device disposed at a predetermined intermediate position of the discharge pipe into calcium oxide, sodium carbonate, and a catalyst. Regarding the structure of such a separation device, a conventionally known technique may be used. For example, a separation device using a separation structure utilizing the difference in specific gravity (sodium carbonate 2.532, calcium oxide 3.3, iron 7.86) is used. The calcium oxide and sodium carbonate separated by the separation device are used for their respective applications, and the catalyst is returned to the catalyst tank 24A and reused as a catalyst.

[0041] In addition, as shown in FIG. 1, it is also preferable that the reaction tank 10 is provided with a surplus gas discharge path 33 separately from the hydrogen discharge path 31, the sodium carbonate discharge path 32, and the calcium oxide discharge path 34. Such a surplus gas discharge path 33 discharges surplus gas that has not been consumed by the secondary chemical reaction, and is particularly for discharging carbon dioxide and ozone assumed as surplus gas. Among these surplus gases, carbon dioxide is reused for adjusting the concentration of carbon dioxide used in the temporary chemical reaction, and ozone is preferably released directly into the atmosphere. In addition, the surplus gas discharge path 33 is provided with a discharge valve 33a that opens and closes manually or automatically at a predetermined intermediate position.

[0042] With the above-described components, the calcium oxide generation device 1 according to the present invention is configured. That is, the calcium oxide generation device 1 is configured by a reaction tank 10 that chemically reacts raw materials, and each input path including a calcium carbonate input path 21 for inputting calcium carbonate, a water input path 22 for inputting water, a sodium input path 23 for inputting sodium, and a catalyst input path 24 for inputting a catalyst, all of which are connected to the reaction tank 10, and each discharge path including a hydrogen discharge path 31 for discharging hydrogen, a sodium carbonate discharge path 32 for discharging sodium carbonate, and a calcium oxide discharge path 34 for discharging calcium oxide, all of which are also connected to the reaction tank 10.

[0043] The calcium oxide production method according to the present invention is realized by the above-described calcium oxide production apparatus 1, and mainly includes a calcium carbonate input step C1 (hereinafter, may be simply referred to as "input step C1") of inputting calcium carbonate, water, and a catalyst as raw materials into the reaction tank 10 through the input paths 21, 22, and 24; an auxiliary heating step C2 of heating the inside of the reaction tank 10 to 950 ° C by the auxiliary heating unit 16; a first reaction step C3 of inputting sodium into the reaction tank 10 through the input path 23, generating sodium hydrogen carbonate and sodium hydride by a chemical reaction of carbon dioxide generated by thermal decomposition of calcium carbonate, water, and the input sodium, increasing the temperature inside the reaction tank 10 by the reaction heat at that time to a high-pressure state, and increasing the production rate of calcium oxide generated from calcium carbonate; a second reaction step C4 of generating sodium carbonate and hydrogen from sodium hydrogen carbonate and sodium hydride by iron as a catalyst in a high-temperature and high-pressure environment inside the reaction tank 10; and a discharge step C5 of discharging the generated calcium oxide, sodium carbonate, and hydrogen from the reaction tank 10 through the discharge paths 32 to 34.

[0044] Hereinafter, the details of the calcium oxide production method according to the present invention will be described. The calcium carbonate input step C1 is a step of inputting raw materials into the reaction tank 10 through the respective input paths 21, 22, and 24. In the reaction tank 10, calcium carbonate sent from the calcium carbonate tank 21A is input through the calcium carbonate input path 21, water stored in the water tank 22A is input through the water input path 22, and a catalyst stored in the catalyst tank 24A is input through the catalyst input path 24. The input amount of each raw material is such that the amount required for the chemical reaction in the reaction tank 10 is input. When expressed in molecular weight, the amount of calcium oxide generated in Equation 1 and the amount expressed as Equation 2 based on the amount of carbon dioxide generated simultaneously are input. The adjustment of the input amount of each such raw material is performed by the respective supply valves 21a, 22a, and 24a.

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

[0046] The first reaction step C3 is a step of introducing sodium into the reaction tank 10 through the input path 23 and temporarily chemically reacting the carbon dioxide generated in the previous auxiliary heating step C2 with the water introduced in the input step C1. Through the chemical reaction of sodium, carbon dioxide, and water, as shown in Equation 2, sodium hydrogen carbonate and sodium hydride are generated. Such a chemical reaction is accompanied by the rapid generation of high heat and high pressure. As a result, the inside of the reaction tank 10 becomes a high-temperature and high-pressure state, promoting the thermal decomposition of the calcium carbonate that remained without being thermally decomposed in the reaction tank 10 and increasing the production rate of calcium oxide.

[0047] The second reaction step C4 is a step of secondarily chemically reacting the sodium hydrogen carbonate and sodium hydride generated in the first reaction step C3 in the reaction tank 10. By chemically reacting sodium hydrogen carbonate and sodium hydride through the catalyst introduced in the input step C1, as shown in Equation 3, hydrogen and sodium carbonate are generated. Such a chemical reaction between sodium hydrogen carbonate and sodium hydride requires not only a catalyst but also high heat (about 400 to 600 ° C) and high pressure (20 to 100 MPa). However, due to the heating by the auxiliary heating unit 16 in the previous auxiliary heating step C2 and the primary chemical reaction in the first reaction step C3, the inside of the reaction tank 10 is already in a high-temperature and high-pressure state, so no further heating or pressurization is required in this step. However, it is also assumed that the required temperature inside the reaction tank 10 cannot be obtained, such as in the case of incomplete reaction in the first reaction step C3. In that case, the temperature adjustment unit 12 provided in the reaction tank 10 is used to appropriately adjust the temperature so that the temperature inside the reaction tank 10 becomes the appropriate temperature.

[0048] The discharging step C5 is a step of discharging the product from the reaction tank 10 through each discharging path, in which calcium oxide generated from the auxiliary heating step C2 to the first reaction step C3 is discharged out of the tank through the calcium oxide discharging path 34, and sodium carbonate generated in the second reaction step C4 is also discharged out of the tank through the sodium carbonate discharging path 32. Then, hydrogen generated in the second reaction step C4 is discharged to the hydrogen tank 31A through the hydrogen discharging path 31. At this time, since the hydrogen generated in the reaction tank 10 is in an ultra-high pressure state, appropriate pressure reduction treatment is performed by the pressure reducing valve 31b provided in the hydrogen discharging path 31, and it is sent to the hydrogen tank 31A in an appropriate pressure state. Also, when discharging calcium oxide from the calcium oxide discharging path 34 and sodium carbonate from the sodium carbonate discharging path 32, the excess catalyst deposited at the lower part of the reaction tank 10 is also discharged together. However, a separation device is interposed to separate calcium oxide, sodium carbonate, and the catalyst, and the separated catalyst is returned to the catalyst tank 24A for reuse.

[0049] As described above, according to the calcium oxide production apparatus and production method according to the present invention, calcium carbonate, water, and a catalyst are introduced into the reaction tank 10, and by heating the inside of the reaction tank 10, a part of the calcium carbonate is thermally decomposed to generate calcium oxide. At the same time, in a primary chemical reaction between carbon dioxide generated during thermal decomposition, water, and sodium introduced after heating the reaction tank 10, sodium hydrogen carbonate and sodium hydride are generated. At the same time, the temperature and pressure inside the reaction tank 10 are increased to promote the thermal decomposition of calcium carbonate, making it easier to generate calcium oxide. Also, in an atmosphere where the temperature and pressure required for hydrogen generation are sufficiently satisfied, a secondary chemical reaction is performed by a catalyst mainly composed of iron, sodium hydrogen carbonate generated in the primary chemical reaction, and sodium hydride, making it possible to generate hydrogen and sodium carbonate.

Industrial Applicability

[0050] The calcium oxide production device and production method according to the present invention provide a new method for producing calcium oxide. At the same time, carbon dioxide, which is a greenhouse gas generated during the thermal decomposition of calcium carbonate, is used as a material for a chemical reaction effective in increasing the temperature and pressure in the tank, contributing to reducing emissions into the atmosphere. It is considered to have extremely high industrial applicability.

Explanation of symbols

[0051] 1 Calcium oxide production device 10 Reaction tank 11 Hollow part 12 Temperature adjustment part 13 Thermometer 14 Pressure gauge 15 Carbon dioxide concentration meter 16 Auxiliary heating part 21 Calcium carbonate input path 21A Calcium carbonate tank 21a Supply valve 22 Water input path 22A Water tank 22a Supply valve 23 Sodium input path 23A Sodium tank 23a Supply valve 24 Catalyst input path 24A Catalyst tank 24a Supply valve 31 Hydrogen discharge path 31A Hydrogen tank 31a Discharge valve 31b Pressure reducing valve 32 Sodium carbonate discharge path 32a Discharge valve 33 Excess gas discharge path 33a Discharge valve 34 Calcium oxide discharge path 34a Discharge valve C0 Calcium oxide production step C1 Calcium oxide input step C2 Auxiliary heating step C3 First reaction step C4 Second Reaction Step C5 Discharge Step

Claims

1. A method for producing calcium oxide from calcium carbonate, comprising the steps of: a calcium oxide injection step of injecting calcium carbonate, water, and iron as a catalyst into a reaction tank made of a pressure vessel; An auxiliary heating step of heating the inside of the reaction vessel to 950°C; a first reaction step in which sodium is introduced into the vessel, and sodium bicarbonate and sodium hydride are generated by a reaction between carbon dioxide generated during the generation of calcium oxide from calcium carbonate, water, and sodium, and the temperature in the reaction vessel is increased by the heat of reaction generated during the reaction, creating a high-pressure state and increasing the rate of generation of calcium oxide from calcium carbonate; a second reaction step in which sodium carbonate and hydrogen are generated from sodium bicarbonate and sodium hydride under high temperature and pressure conditions in the presence of iron as a catalyst; a discharge step of discharging the produced calcium oxide, hydrogen and sodium carbonate from the reaction tank through each discharge path; A method for producing calcium oxide comprising the steps of:

2. A calcium oxide generating apparatus for generating calcium oxide from calcium carbonate, comprising: The system is composed of a reaction tank made 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 input path is composed of a calcium carbonate input path, a water input path, a sodium input path, and a catalyst input path, Each of the input paths is connected to a reaction tank at one end, The discharge path is composed of a calcium oxide discharge path, a hydrogen discharge path, and a sodium carbonate discharge path, Each discharge path is connected to a reaction tank at one end, Calcium carbonate, water, and iron 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 the carbon dioxide generated during the production of calcium oxide from calcium carbonate, the water added, and sodium, and 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 proceeds, Hydrogen and sodium carbonate are produced by a chemical reaction between the sodium bicarbonate produced by the catalyst and sodium hydride. A calcium oxide generating apparatus characterized in that calcium oxide, hydrogen, and sodium carbonate finally generated are discharged from each discharge path.

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