Carbonation curing system and carbonation curing method

Abstract

To provide a carbonation curing system and a carbonation curing method capable of improving the reactivity of CO2 gas and concrete.SOLUTION: A carbonation curing system and a carbonation curing method include at least two or more carbonation curing parts, a gas distribution part for distributing a gas containing CO2 between the carbonation curing parts, a CO2 gas inlet for supplying the gas containing CO2, and a CO2 gas outlet for discharging the gas containing CO2 with a reduced CO2 concentration, wherein the carbonation curing parts are provided with concretes with different degrees of progress of carbonation curing, and the gas containing CO2 is supplied along a distribution path of the gas containing CO2 in descending order of the degree of progress of carbonation curing.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a carbonation curing system and a carbonation curing method. [Background technology]

[0002] To mitigate global warming, reducing carbon dioxide emissions, the main cause of global warming, has become a crucial issue. In this regard, various manufacturing facilities have been proposed for producing concrete products in which carbon dioxide is forcibly absorbed or carbonated during the manufacturing process.

[0003] For example, Patent Document 1 describes a carbon dioxide curing system and method comprising a primary curing room and a secondary curing room for curing concrete products, wherein carbon dioxide is supplied to the secondary curing room for carbon dioxide curing. Patent Document 2 also describes a carbon dioxide curing facility that utilizes a thermal power plant as a carbon dioxide supply source and uses exhaust gas discharged from the thermal power plant. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-16659 [Patent Document 2] Japanese Patent Publication No. 2012-126623 [Overview of the project] [Problems that the invention aims to solve]

[0005] The carbonation curing systems described in Patent Documents 1 and 2 perform carbonation curing in a curing tank, remove the concrete after carbonation curing is complete, and then place the next batch of concrete in the curing tank, thereby performing carbonation curing sequentially. However, as the carbonation curing of concrete progresses, the reactivity with CO2 gas decreases, so in the latter half of the curing period, CO2 gas is not used much and is discharged. Therefore, there was a need for a system in which CO2 gas and concrete react more efficiently.

[0006] This invention has been made in view of these circumstances, and aims to provide a carbonation curing system and a carbonation curing method that can improve the reaction efficiency between CO2 gas and concrete. [Means for solving the problem]

[0007] The inventors of the present invention conducted intensive research to solve the above problems and found that the problems can be solved by providing two or more carbonation curing sections and controlling the progress of carbonation curing of concrete in the carbonation curing sections and the flow path of gas containing CO2, leading to the present invention. In other words, the present invention is as follows. [1] A carbonation curing system used in the manufacture of concrete, comprising: at least two or more carbonation curing sections; a gas flow section provided between each of the carbonation curing sections for circulating a CO2-containing gas between the carbonation curing sections; a CO2 gas supply port for supplying a CO2-containing gas to the system; and a CO2 gas outlet for discharging a CO2-containing gas with a reduced CO2 concentration from the system, wherein the CO2 gas supply port is provided in at least one of the carbonation curing sections, and the CO2 gas outlet is provided in at least one of the carbonation curing sections different from the carbonation curing section in which the CO2 gas supply port is provided, and each of the carbonation curing sections is provided with concrete at different stages of carbonation curing, and the CO2-containing gas is supplied along the CO2-containing gas flow path from concrete at a high stage of carbonation curing to concrete at a low stage of carbonation curing. [2] After removing the concrete that has been carbon-cured, the concrete in the carbon-curing section downstream of the CO2-containing gas flow path is transported to the carbon-curing section upstream, and the uncured concrete is placed in the carbon-curing section at the downstream end of the flow path, the carbon-curing system according to [1]. [3] The carbonation curing system according to [1], wherein each of the carbonation curing sections is provided with a CO2 gas supply port and a CO2 gas outlet, and the CO2 gas supply port and the CO2 gas outlet are equipped with a valve that changes the carbonation curing section from which the CO2-containing gas is supplied and the carbonation curing section from which the CO2-containing gas with reduced CO2 concentration is discharged, and after removing the concrete that has been carbonation cured, uncured concrete is placed in the removed carbonation curing section, and the valve is used to change the supply of the CO2-containing gas from the downstream carbonation curing section adjacent to the carbonation curing section in which the uncured concrete is placed in the CO2-containing gas flow path, and the discharge of the CO2-containing gas with reduced CO2 concentration is performed from the carbonation curing section in which the uncured concrete is placed. [4] A carbonation curing method used in the production of concrete, wherein at least two or more carbonation curing sections have concrete at different stages of carbonation curing, and a gas containing CO2 is supplied so that the concrete progresses from the concrete with a high stage of carbonation curing to the concrete with a low stage of carbonation curing. [5] The carbonation curing method according to [4], wherein concrete that has been carbonized is removed from the carbonation curing section, the concrete from the carbonation curing section downstream of the CO2-containing gas flow path is transported to the carbonation curing section upstream, and uncured concrete is placed in the carbonation curing section at the downstream end of the flow path. [6] The carbonation curing method according to [4], wherein concrete that has been carbonized is removed from the carbonation curing section, uncured concrete is placed in the carbonation curing section, the CO2-containing gas is supplied from the downstream carbonation curing section adjacent to the carbonation curing section where the uncured concrete is placed, in the CO2-containing gas distribution path, and the CO2-containing gas with reduced CO2 concentration is discharged from the carbonation curing section where the uncured concrete is placed. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a carbonation curing system and a carbonation curing method that can improve the reaction efficiency between CO2 gas and concrete. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic side view showing the carbonation curing system according to the first embodiment. [Figure 2] This is a schematic side view showing a modified example of the carbonation curing system of the first embodiment. [Figure 3] This is a schematic side view showing the carbonation curing system according to the second embodiment. [Figure 4] This is a schematic top view showing a modified example of the carbonation curing system of the second embodiment. [Modes for carrying out the invention]

[0010] The carbonation curing system and carbonation curing method of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

[0011] [Carbonated Curing System] The carbonation curing system of the present invention is a carbonation curing system used in the manufacture of concrete, comprising: at least two or more carbonation curing sections; a gas flow section provided between each carbonation curing section for circulating CO2-containing gas between the carbonation curing sections; a CO2 gas supply port for supplying CO2-containing gas to the system; and a CO2 gas outlet for discharging CO2-containing gas with reduced CO2 concentration from the system, wherein the supply port is provided in at least one carbonation curing section, and the outlet is provided in at least one carbonation curing section different from the carbonation curing section in which the supply port is provided, and each carbonation curing section is provided with concrete at different stages of carbonation curing, and the CO2-containing gas is supplied along the CO2-containing gas flow path so as to concrete at higher stages of carbonation curing progress to concrete at lower stages of carbonation curing.

[0012] <First Embodiment> Figure 1 is a schematic side view of the carbonation curing system according to the first embodiment. As shown in Figure 1, the carbonation curing system 10 according to the first embodiment includes a first carbonation curing tank 12a, a second carbonation curing tank 12b, and a third carbonation curing tank 12c, which correspond to the carbonation curing section of the present invention for carbonation curing of concrete (hereinafter collectively referred to as "carbonation curing tanks 12a, 12b, and 12c"). Furthermore, the first carbonation curing tank 12a is equipped with a CO2 gas supply port 14 for supplying CO2-containing gas to the carbonation curing system 10, and the third carbonation curing tank 12c is equipped with a CO2 gas outlet 16 for discharging CO2-containing gas with a reduced CO2 concentration from the carbonation curing system 10. In addition, gas flow sections 18, 18 are provided between the first carbonation curing tank 12a and the second carbonation curing tank 12b, and between the second carbonation curing tank 12b and the third carbonation curing tank 12c to circulate CO2-containing gas between each carbonation curing tank. In this invention, the "CO2-containing gas with a reduced CO2 concentration" discharged from the CO2 gas outlet 16 means that it also includes gas that does not contain CO2 because CO2 has been almost completely absorbed in the carbonation curing tanks 12a, 12b, and 12c.

[0013] The CO2-containing gas supplied from the CO2 gas supply port 14 is not particularly limited as long as it contains CO2, and examples include gas consisting solely of CO2 produced by known methods; exhaust gas from thermal power plants that use coal, heavy oil, natural gas, etc. as fuel; exhaust gas from steel mills; exhaust gas from concrete plants; and exhaust gas from chemical plants. These may be used individually or in combination of two or more types. Among these, various exhaust gases are preferred because, from the standpoint of reducing environmental impact, it is necessary to fix CO2 in an energy-saving manner. The various exhaust gases may also be gases in which the CO2 concentration has been increased by treating the exhaust gas (for example, carbon dioxide recovered from boiler exhaust gas and compressed in a gas cylinder). When the exhaust gas of each of the above facilities is used as the gas containing CO₂ for the CO₂ gas supply port 14, it can be branched from the flue that connects the exhaust gas discharge port of each facility and the chimney and connected to the CO₂ gas supply port 14, so that the exhaust gas containing CO₂ can be used. Also, it can be connected to a gas cylinder to supply the gas containing CO₂ from the gas cylinder.

[0014] Note that the gas containing CO₂ may contain gases other than CO₂. There is no particular limitation on the gas other than CO₂, and examples include nitrogen, oxygen, water vapor, carbon monoxide, hydrogen sulfide, carbonyl sulfide, sulfur dioxide, nitrogen dioxide, methane, hydrogen, and the like. The concentration of CO₂ in the gas containing CO₂ is not particularly limited, but from the viewpoint of efficiently performing carbonation curing of concrete and producing concrete, 1% by volume or more is preferable, and 5% by volume or more is more preferable. As described above, it is also possible to concentrate CO₂ from the gas containing CO₂ to obtain a preferable CO₂ concentration.

[0015] The CO₂ gas supply port 14 that supplies the gas containing CO₂, and the supply ports 18a, 18a of the gas flow part 18 that supplies the gas containing CO₂ to the carbonation curing tanks 12b, 12c are preferably provided below the carbonation curing tanks 12a, 12b, 12c. Also, the CO₂ gas discharge port 16 that discharges the gas containing CO₂, and the discharge ports 18b, 18b of the gas flow part 18 that discharges the gas containing CO₂ from the carbonation curing tanks 12a, 12b are preferably above the CO₂ gas supply port 14 and the supply ports 18a, 18a of the gas flow part 18, and are provided above the carbonation curing tanks 12a, 12b, 12c. Since the specific gravity of the gas containing CO₂ decreases as the concentration of CO₂ decreases, the gas with a decreased CO₂ concentration tends to move to the upper side inside the carbonation curing tanks 12a, 12b, 12c. With the above configuration, the gas with a low CO₂ concentration is easily discharged, and the gas with a high CO₂ concentration tends to stay inside the carbonation curing tanks 12a, 12b, 12c, so that the gas containing CO₂ can be efficiently reacted.

[0016] Furthermore, the CO2-containing gas emitted from the carbonation curing system 10 is discharged from a CO2 gas outlet 16 provided in the third carbonation curing section 12c. If the emitted CO2-containing gas contains harmful substances other than CO2, it can be sent from the CO2 gas outlet 16 to a harmful substance removal means (not shown) to remove the harmful substances before being discharged outside the carbonation curing system 10.

[0017] Each of the carbonation curing tanks 12a, 12b, and 12c is provided with concrete 22a, 22b, and 22c at different stages of carbonation curing. The concrete 22a, 22b, and 22c are arranged within the carbonation curing tanks 12a, 12b, and 12c along the gas flow path containing CO2, from concrete 22a with a higher stage of carbonation curing to concrete 22c with a lower stage. Specifically, Figure 1(a) shows a gas flow path from the first carbonation curing tank 12a to the third carbonation curing tank 12c, with concrete 22a, which has the highest stage of carbonation curing, placed in the first carbonation curing tank 12a, followed by concrete 22b and 22c, which have lower stages of carbonation curing, in the second carbonation curing tank 12b and the third carbonation curing tank 12c, respectively.

[0018] The degree of carbonation curing can be evaluated by monitoring the CO2 concentration, gas flow rate, temperature, and pressure using sensors installed at the CO2 gas supply port 14, gas flow section 18, and CO2 gas outlet 16, and assessing the CO2 consumption. Alternatively, it can be evaluated by monitoring the mass of the concrete, as its mass increases as carbonation progresses. For example, the CO2 concentration C1 (vol%) and gas flow rate F1 (m³) of the CO2-containing gas flowing through the CO2 gas supply port 14 or gas flow section 18 into one carbonation curing tank within a certain time period Δt (s) can be evaluated. 3From the flow rate F1 (m³ / s), pressure P1 (Pa), temperature T1 (K), molar mass m (kg / mol) of CO2, and gas constant R = 8.31 (J / mol·K), the mass ΔM1 (kg) of CO2 flowing into the carbonation curing tank is calculated from ΔM1 = mC1P1F1Δt / 100RT1. Also, the CO2 concentration C2 (vol%) of the gas containing CO2 flowing through the gas flow section 18 or the CO2 gas outlet 16 discharged from this carbonation curing tank, the gas flow rate F2 (m 3 From the flow rate F2 (m³ / s), pressure P2 (Pa), temperature T2 (K), molar mass m (kg / mol) of CO2, and gas constant R = 8.31 (J / mol·K), the mass ΔM2 (kg) of CO2 flowing out of the carbonation curing tank is calculated from ΔM2 = mC2P2F2Δt / 100RT2. Then, by calculating ΔM = ΔM1 - ΔM2, the mass ΔM of CO2 absorbed by the concrete during Δt can be obtained. Also, the mass change due to the release or absorption of H2O by the concrete can be obtained by measuring the concentration of water vapor with a water vapor sensor and performing the same calculation as above. Therefore, by subtracting the amount of H2O released or absorbed from the mass change of the concrete, the mass ΔM of CO2 absorbed by the concrete during Δt can be obtained. By determining the mass ΔM of CO2 absorbed by the concrete in this way, the cumulative value M of ΔM in the i-th carbonation curing section during the curing time 0 to t i can be used to determine the timing of removing the concrete. When carbonating in a system having n carbonation curing sections with the target CO2 absorption amount of the concrete being M, the CO2 absorption amount M i in the i-th (0 ≦ i ≦ n) carbonation curing section becoming about M / n serves as a guide for removing and moving the concrete. When the carbonation of the i-th carbonation curing section is slower than the average of all the curing sections, M i < M / n, and when the carbonation of the i-th carbonation curing section is faster than the average of all the curing sections, M i > M / n, it is advisable to remove and move the concrete. Also, the total value ΣM of the CO2 absorption amounts in the carbonation curing sections from the 1st to the nth iWhen it reaches M, the CO₂ absorption amount per curing part becomes M / n, so it can be determined that the target CO₂ absorption amount has been reached, and the concrete may be taken out and moved. Note that the taking out and moving of the concrete do not need to be performed after ΣM i reaches M. For example, when ΣM i reaches 90% or more of M, it can be determined that carbonation curing has been sufficiently performed, and the concrete may be taken out and moved. In addition, the progress of carbonation curing can be determined not only by the degree of the progress of the above-mentioned carbonation curing but also by various solid analyses such as thermogravimetric differential thermal analysis of concrete.

[0019] The concretes 22a, 22b, and 22c provided in the respective carbonation curing tanks 12a, 12b, and 12c are provided so as to be movable in the respective carbonation curing tanks 12a, 12b, and 12c by a transfer mechanism 20. As the transfer mechanism 20, a cart or the like can be used.

[0020] In addition, in order to efficiently perform carbonation curing in the carbonation curing tank, it is preferable that the respective carbonation curing tanks 12a, 12b, and 12c are sealed except for the locations where the gas containing CO₂ is supplied and discharged into and from the carbonation curing tanks 12a, 12b, and 12c. Further, the carbonation curing tanks 12a, 12b, and 12c have operation doors 24 (see FIG. 1(b)), and the concretes 22a, 22b, and 22c in the carbonation curing tanks 12a, 12b, and 12c can be carried in, taken out, and moved.

[0021] Next, the carbonation curing method of the carbonation curing system 10 according to the present embodiment will be described. The carbonation curing system 10 of the first embodiment is provided such that the progress of carbonation curing decreases from the concrete 22a with a high progress of carbonation curing to the concrete 22c along the flow path of the gas containing CO₂ as described above. By arranging concretes 22a, 22b, and 22c in this manner, a gas with a high CO2 concentration can be reacted with concrete 22a, which has a high degree of carbonation curing progressed, thus allowing carbonation curing to be advanced on concrete where the reaction has slowed down as carbonation curing progresses. Furthermore, the gas supplied from the first carbonation curing tank 12a to the second carbonation curing tank 12b through the gas flow section 18 has a moderate CO2 concentration because carbonation does not progress easily in the first carbonation curing tank 12a, so not much CO2 is consumed. Therefore, carbonation curing can be performed on concrete 22b in the second carbonation curing tank 12b, where carbonation curing has progressed to a certain extent. Moreover, the gas supplied from the second carbonation curing tank 12b to the third carbonation curing tank 12c through the gas flow section 18 has a low CO2 concentration because CO2 is consumed in the second carbonation curing tank 12b, where carbonation curing is taking place. However, the concrete 22c provided in the third carbonation curing tank 12c is concrete with a low degree of carbonation curing progress, and is more easily carbonized than the concrete provided in the first carbonation curing tank 12a and the second carbonation curing tank 12b, so carbonation curing can be carried out even with gases with low CO2 concentrations.

[0022] In this way, by supplying CO2-containing gas along the CO2-containing gas flow path from concrete 22a, which has a high degree of carbonation curing, to concrete 22c, which has a low degree of carbonation curing, high-concentration CO2 gas is brought into contact with concrete 22a, which has a high degree of carbonation curing, thereby promoting carbonation curing even for concrete that is difficult to cure. Furthermore, concrete 22c, which has a low degree of carbonation curing, will come into contact with low-concentration CO2 gas after passing through carbonation curing tanks 12a and 12b, but because the degree of carbonation curing is low, carbonation curing can still be promoted even when exposed to low-concentration CO2 gas. Therefore, CO2 in the CO2-containing gas can be used effectively, improving reaction efficiency. In addition, CO2 emissions can be reduced.

[0023] Furthermore, the carbonation reaction is an exothermic reaction, and if the reaction is rapid, the temperature of the concrete and curing room will rise, and the concrete will dry out. As described above, by contacting concrete 22a, which is highly carbonicated, with a gas with a high CO2 concentration; concrete 22b, which is moderately carbonicated, with a gas with a moderate CO2 concentration; and concrete 22c, which is less carbonicated, with a gas with a low CO2 concentration, the reaction rate and temperature can be made uniform, thereby suppressing unevenness in the carbonication curing of the concrete and excessive drying.

[0024] Once the carbonation curing in the first carbonation curing tank 12a is complete, the operating door 24 is opened as shown in Figure 1(b), and the concrete 22a in the first carbonation curing tank 12a is removed. After removing the concrete 22a from the first carbonation curing tank 12a, the concrete 22b in the carbonation curing tank downstream of the CO2-containing gas flow path (the second carbonation curing tank 12b) is moved by the transport mechanism 20 to the adjacent upstream carbonation curing tank (the first carbonation curing tank 12a). Similarly, the concrete 22c in the carbonation curing tank downstream of the CO2-containing gas flow path (the third carbonation curing tank 12c) is moved by the transport mechanism 20 to the adjacent upstream carbonation curing tank (the second carbonation curing tank 12b). Then, uncured concrete 22d is placed in the carbonation curing tank at the downstream end of the distribution route (inside the third carbonation curing tank 12c).

[0025] In this way, after removing the concrete 22a that has completed carbonation curing, the concrete in the downstream carbonation curing tank is transported along the CO2-containing gas flow path to the adjacent upstream carbonation curing tank, and the uncured concrete is placed in the carbonation curing tank at the furthest downstream end of the CO2-containing gas flow path. This allows the concrete to be placed in a manner that progresses from concrete with a high degree of carbonation curing to concrete with a low degree of carbonation curing along the CO2-containing gas flow path. As a result, even after removing the concrete that has completed carbonation curing, the CO2-containing gas can be efficiently used for carbonation curing.

[0026] Furthermore, the carbonation curing system of the present invention may include a conventional steam curing section in addition to the carbonation curing section where carbonation curing is performed. The concrete used in the carbonation curing section may be concrete that has been cured by steam.

[0027] (modified version) Figure 2 is a schematic side view showing a modified example of the carbonation curing system of the first embodiment. The carbonation curing system 50 shown in Figure 2 differs from the carbonation curing system 10 shown in Figure 1, in that it has three carbonation curing sections (first carbonation curing section 52a, second carbonation curing section 52b, and third carbonation curing section 52c (hereinafter collectively referred to as "carbonation curing sections 52a, 52b, and 52c")) within a single carbonation curing tank 51. Furthermore, the carbonation curing tank 51 has a CO2 gas supply port 54 on the first carbonation curing section 52a side and a CO2 gas discharge port 56 on the third carbonation curing section 52c side, with a gas flow section 58 between each of the carbonation curing sections 52a, 52b, and 52c. This creates a flow path within the carbonation curing tank 51 through which gas containing CO2 flows from the carbonation curing section 52a to the third carbonation curing section 52c.

[0028] In the carbonation curing system 50 shown in Figure 2, the concrete 62a, 62b, and 62c provided in each carbonation curing section 52a, 52b, and 52c are arranged so that the concrete 62a, which is at a high stage of carbonation curing, is in order to the concrete 62c, which is at a low stage of carbonation curing, along the gas flow path containing CO2. By installing the concrete in this way, similar to the carbonation curing system 10 shown in Figure 1, the concrete 62a, which is at a high stage of carbonation curing, is exposed to a gas with a high CO2 concentration, thereby promoting carbonation curing even for concrete that is difficult to cure. Furthermore, the concrete 62c, which is at a low stage of carbonation curing, is exposed to a gas with a low CO2 concentration after passing through the carbonation curing sections 52a and 52b. However, because the carbonation curing is at a low stage, carbonation curing can still be promoted even when exposed to a gas with a low CO2 concentration. Therefore, the CO2 in the gas containing CO2 can be used effectively, improving reaction efficiency. In addition, the amount of CO2 emitted can be reduced.

[0029] The carbonation curing sections 52a, 52b, and 52c are equipped with a transport mechanism 60, such as a belt conveyor or trolley. The transport mechanism 60 allows the concrete 62b and 62c provided in each carbonation curing section 52b and 52c to be transported to the carbonation curing section upstream of the CO2-containing gas flow path. Once the carbonation curing of the concrete 62a in the first carbonation curing section 52a is complete, the cured concrete 62a is removed from the first carbonation curing section 52a, as shown in Figure 2(b). Then, the transport mechanism 60 moves the concrete 62b from the second carbonation curing section 52b to the first carbonation curing section 52a. Similarly, the transport mechanism 60 moves the concrete 62c from the third carbonation curing section 52c to the second carbonation curing section 52b. Then, uncured concrete 62d is placed in the third carbonation curing section 52c.

[0030] In this way, after removing the concrete 62a that has completed carbonation curing, the concrete installed in the downstream carbonation curing section is transported along the CO2-containing gas flow path to the adjacent upstream carbonation curing section, and uncured concrete is installed in the downstream carbonation curing section of the CO2-containing gas flow path. This allows the concrete to be installed in a manner that progresses from concrete with a high degree of carbonation curing to concrete with a low degree of carbonation curing along the CO2-containing gas flow path. As a result, even after removing the concrete that has completed carbonation curing, the CO2-containing gas can be efficiently used for carbonation curing.

[0031] <Second Embodiment> Figure 3 is a schematic side view showing the carbonation curing system according to the second embodiment. The carbonation curing system according to the second embodiment comprises four carbonation curing tanks, each equipped with a CO2 gas supply port for supplying CO2-containing gas and a CO2 gas discharge port for discharging CO2-containing gas. This makes it possible to change the position of the carbonation curing tanks that supply CO2-containing gas and the position of the carbonation curing tanks that discharge CO2-containing gas, and it differs from the carbonation curing system of the first embodiment in that it is possible to change the flow path of CO2-containing gas without moving the concrete inside the carbonation curing tanks.

[0032] As shown in Figure 3, the carbonation curing system 110 of the second embodiment includes a first carbonation curing tank 112a, a second carbonation curing tank 112b, a third carbonation curing tank 112c, and a fourth carbonation curing tank 112d, which correspond to the carbonation curing section of the present invention and perform carbonation curing of concrete (hereinafter collectively referred to as "carbonation curing tanks 112a, 112b, 112c, and 112d"). It also includes CO2 gas supply ports 114a, 114b, 114c, and 114d for supplying gas containing CO2 to each of the carbonation curing tanks 112a, 112b, 112c, and 112d, and CO2 gas outlet ports 116a, 116b, 116c, and 116d for discharging gas containing CO2. Furthermore, a gas flow section 118 is provided between the first carbonation curing tank 112a and the second carbonation curing tank 112b, between the second carbonation curing tank 112b and the third carbonation curing tank 112c, between the third carbonation curing tank 112c and the fourth carbonation curing tank 112d, and between the fourth carbonation curing tank 112d and the first carbonation curing tank 112a for circulating gas containing CO2. The gas flow section 118 is partially shared with the CO2 gas supply ports 114a, 114b, 114c, 114d and the CO2 gas outlet ports 116a, 116b, 116c, 116d, and is provided by branching using a valve 126. Note that the CO2 gas supply ports 114a, 114b, 114c, 114d and CO2 gas outlet ports 116a, 116b, 116c, 116d shown in Figure 3 are partially shared with the gas flow section 118, but they can also be provided separately from the gas flow section 118.

[0033] Furthermore, each of the CO2 gas supply ports 114a, 114b, 114c, 114d and each of the CO2 gas outlet ports 116a, 116b, 116c, 116d is provided so that the carbonation curing tank to which the CO2-containing gas is supplied and the carbonation curing tank to which the gas is discharged can be changed via the valve 126. This makes it possible to change the location of the carbonation curing tank to which the CO2-containing gas is supplied and the location of the carbonation curing tank to which the CO2-containing gas is discharged, thereby changing the flow path of the CO2-containing gas.

[0034] Furthermore, each of the carbonation curing tanks 112a, 112b, 112c, and 112d is equipped with concrete 122a, 122b, 122c, and 122d with different degrees of carbonation curing, and within each carbonation curing tank 112a, 112b, 112c, and 112d, the concrete is arranged so that it progresses from concrete 122a with a high degree of carbonation curing to concrete 122d with a low degree of carbonation curing, along the gas flow path containing CO2. For example, in Figure 3(a), gas containing CO2 is supplied to the carbonation curing system 110 from the CO2 gas supply port 114a of the first carbonation curing tank 112a, and gas containing CO2 is discharged from the CO2 gas outlet 116d of the fourth carbonation curing tank 112d. At this time, the valve 126 is controlled so that gas containing CO2 flows through the gas flow section 118 from the first carbonation curing tank 112a to the second carbonation curing tank 112b, from the second carbonation curing tank 112b to the third carbonation curing tank 112c, and from the third carbonation curing tank 112c to the fourth carbonation curing tank 112d. As a result, the flow path for the gas containing CO2 becomes a flow path from the first carbonation curing tank 112a to the fourth carbonation curing tank 112d. The concrete is arranged as follows: the first carbonation curing tank 112a contains the concrete 122a with the highest degree of carbonation curing, followed by the second carbonation curing tank 112b containing concrete 122b with a moderately high degree of carbonation curing, the third carbonation curing tank 112c containing concrete 122c with a moderately low degree of carbonation curing, and the fourth carbonation curing tank 112d containing concrete 122d with a low degree of carbonation curing.

[0035] Each of the carbonation curing tanks 112a, 112b, 112c, and 112d is preferably sealed except for the points where gas containing CO2 is supplied to and discharged from the carbonation curing tanks 112a, 112b, 112c, and 112d, in order to efficiently carry out carbonation curing within the carbonation curing tank.

[0036] Next, the carbonation curing method of the carbonation curing system 110 according to this embodiment will be described. In the carbonation curing system 110 of the second embodiment, as described above, concrete is provided along the gas flow path containing CO2, from concrete 122a with a high degree of carbonation curing to concrete 122d with a low degree of carbonation curing.

[0037] By arranging concretes 122a, 122b, 122c, and 122d in this manner, a gas with a high CO2 concentration can be reacted with concrete 122a, which has a high degree of carbonation curing progress. This allows for further carbonation curing of concrete where the reaction has slowed down due to the progress of carbonation curing. Furthermore, the gas supplied from the first carbonation curing tank 112a to the second carbonation curing tank 112b through the gas flow section 118 does not consume much CO2 in the first carbonation curing tank 112a because carbonation does not progress easily there, and a gas with a relatively high CO2 concentration is supplied. Therefore, it is possible to cure concrete 122b in the second carbonation curing tank 112b, where carbonation curing has progressed to a certain extent. Furthermore, the gas supplied from the second carbonation curing tank 112b to the third carbonation curing tank 112c through the gas flow section 118 has a relatively low CO2 concentration because CO2 is consumed in the second carbonation curing tank 112b due to the ongoing carbonation curing. However, the concrete 122c provided in the third carbonation curing tank 112c is concrete that has undergone a relatively low degree of carbonation curing and is more easily carbonized than the concrete 122a and 122b provided in the first carbonation curing tank 112a and the second carbonation curing tank 112b. Therefore, carbonation curing can proceed even with a gas that has a low CO2 concentration. Similarly, with respect to the fourth carbonation curing tank 112d, the gas supplied from the third carbonation curing tank 112c through the gas flow section 118 to the fourth carbonation curing tank 112d is a gas with a low CO2 concentration because CO2 has been consumed in the third carbonation curing tank 112c. However, the concrete 122d provided in the fourth carbonation curing tank 112d is concrete with a low degree of carbonation curing progress, and is more easily carbonized than the concrete provided in the first carbonation curing tank 112a, the second carbonation curing tank 112b, and the third carbonation curing tank 112c, so carbonation curing can proceed even with a gas with a low CO2 concentration.

[0038] In this way, by supplying CO2-containing gas along the CO2-containing gas flow path from concrete 122a with a high degree of carbonation curing to concrete 122d with a low degree of carbonation curing, high-concentration CO2 gas is brought into contact with concrete 122a with a high degree of carbonation curing, thereby promoting carbonation curing even for concrete that is difficult to cure. Furthermore, concrete 122d with a low degree of carbonation curing will come into contact with low-concentration CO2 gas as it passes through the carbonation curing tank, but because the carbonation curing is slow, contact with low-concentration CO2 gas can promote carbonation curing. Therefore, the CO2 in the CO2-containing gas can be used effectively, improving reaction efficiency. In addition, CO2 emissions can be reduced.

[0039] Furthermore, the carbonation reaction is an exothermic reaction, and if the reaction is rapid, the temperature of the concrete and curing room will rise, and the concrete will dry out. As described above, by contacting concrete 22a, which is highly carbonicated, with a gas with a high CO2 concentration; concrete 22b, which is moderately carbonicated, with a gas with a moderate CO2 concentration; and concrete 22c, which is less carbonicated, with a gas with a low CO2 concentration, the reaction rate and temperature can be made uniform, thereby suppressing unevenness in the carbonication curing of the concrete and excessive drying.

[0040] Once the carbonation curing in the first carbonation curing tank 112a is complete, the concrete 122a is removed from the first carbonation curing tank 112a, as shown in Figure 3(b). After removing the concrete 122a from the first carbonation curing tank 112a, uncured concrete 122e is placed in the first carbonation curing tank 112a. By placing the concrete in this manner, the concrete in the carbonation curing tanks is arranged so that the degree of carbonation curing progresses in the order of the second carbonation curing tank 112b, the third carbonation curing tank 112c, the fourth carbonation curing tank 112d, and the first carbonation curing tank 112a.

[0041] Then, once the uncured concrete 122e has been placed in the first carbonation curing tank 112a, CO2-containing gas is supplied into the carbonation curing system 110. At this time, valve 126 is controlled to supply the CO2-containing gas from the second carbonation curing tank 112b, which is adjacent to the carbonation curing tank 112a where the uncured concrete 122e is placed, and is downstream of the previous CO2-containing gas flow path. Valve 126 is also controlled to discharge the CO2-containing gas from the carbonation curing section where the uncured concrete is placed, that is, from the first carbonation curing tank 112a. Specifically, in the case of the flow path in Figure 3(a), the valve 126 of the gas supply port 114b provided in the second carbonation curing tank 112b is changed to the supply side of the CO2-containing gas, and the valve 126 of the gas discharge port 116a provided in the first carbonation curing tank 112a is changed to the discharge side, so that the CO2-containing gas does not flow through the gas flow section 118 between the first carbonation curing tank 112a and the second carbonation curing tank 112b. Then, the valve 126 is controlled so that gas passes through the gas flow section 118 between the fourth carbonation curing tank 112d and the first carbonation curing tank 112a. As a result, the gas flow path for CO2-containing gas becomes the second carbonation curing tank 112b, the third carbonation curing tank 112c, the fourth carbonation curing tank 112d, and the first carbonation curing tank 112a, so that the concrete 122b, which is at a higher stage of carbonation curing, progresses to the concrete 122e, which is at a lower stage.

[0042] Subsequently, after removing the concrete that has completed carbonation curing and installing the uncured concrete, a gas flow path containing CO2 is established from the carbonation curing tank downstream of the uncured concrete to the carbonation curing tank containing the uncured concrete. This allows for efficient use of CO2 in carbonation curing by exposing concrete with a high CO2 concentration to gas with a high degree of carbonation curing progress and concrete with a low CO2 concentration to gas with a low degree of carbonation curing progress.

[0043] (modified version) Figure 4 is a schematic top view showing a modified example of the carbonation curing system of the second embodiment. The carbonation curing system 150 shown in Figure 4 differs from the carbonation curing system 110 shown in Figure 3, in that each carbonation curing section (carbonation curing tank) is provided individually, in that it has four carbonation curing sections (first carbonation curing section 152a, second carbonation curing section 152b, third carbonation curing section 152c, and fourth carbonation curing section 152d (hereinafter collectively referred to as "carbonation curing sections 152a, 152b, 152c, and 152d")) by dividing the inside of a single carbonation curing tank 151 with a wall 153.

[0044] Furthermore, the carbonation curing system 150 shown in Figure 4 also includes CO2 gas supply ports 154a, 154b, 154c, and 154d for supplying CO2-containing gas to each of the carbonation curing sections 152a, 152b, 152c, and 152d, and CO2 gas outlet ports 156a, 156b, 156c, and 156d for discharging CO2-containing gas. Furthermore, gas circulation sections 158 are provided between the first carbonation curing section 152a and the second carbonation curing section 152b, between the second carbonation curing section 152b and the third carbonation curing section 152c, between the third carbonation curing section 152c and the fourth carbonation curing section 152d, and between the fourth carbonation curing section 152d and the first carbonation curing section 152a, for circulating gas containing CO2. Preferably, the gas flow section 158 is provided to be openable and closable so that the order in which the CO2-containing gas flows through different carbonation curing sections can be controlled.

[0045] Each of the CO2 gas supply ports 154a, 154b, 154c, and 154d, and each of the CO2 gas outlet ports 156a, 156b, 156c, and 156d, is provided via a valve 166 to change the carbonation curing tank to which the CO2-containing gas is supplied and the carbonation curing tank to which it is discharged. This makes it possible to change the location of the carbonation curing tank to which the CO2-containing gas is supplied and the location of the carbonation curing tank to which the CO2-containing gas is discharged, thereby changing the flow path of the CO2-containing gas.

[0046] In Figure 4(a), by opening the valve 166 of the CO2 gas supply port 154a of the first carbonation curing section 152a and the valve 166 of the CO2 gas outlet 156d of the fourth carbonation curing section 152d, and closing the other valves 166, gas containing CO2 is supplied to the carbonation curing system 150 from the CO2 gas supply port 154a of the first carbonation curing section 152a, and gas containing CO2 is discharged from the CO2 gas outlet 156d of the fourth carbonation curing section 152d. At this time, it is preferable to keep the gas flow section 158 between the fourth carbonation curing section 152d and the first carbonation curing section 152a closed so that gas containing CO2 does not flow from the fourth carbonation curing section 152d to the first carbonation curing section 152a.

[0047] In the carbonation curing system 150 shown in Figure 4, by arranging the carbonation curing sections 152a, 152b, 152c, and 152d along the gas flow path containing CO2, from concrete with a high degree of carbonation curing to concrete with a low degree of curing, the CO2 in the gas can be used effectively, improving the reaction efficiency. In addition, the amount of CO2 emitted can be reduced.

[0048] Furthermore, once the carbonation curing of the concrete 162a in the first carbonation curing section 152a is complete, as shown in Figure 4(b), the valve 166 of the CO2 gas supply port 154a of the first carbonation curing section 152a and the valve 166 of the CO2 gas outlet 156d of the fourth carbonation curing section 152d are closed, and the gas flow section 158 of the fourth carbonation curing section 152d and the first carbonation curing section 152a are opened. Then, the concrete 162a is removed from the first carbonation curing section 152a, and the uncured concrete 162e is placed in the first carbonation curing section 152a. Subsequently, the gas flow sections 158 of the first carbonation curing section 152a and the second carbonation curing section 152b are closed, and the valve 166 of the CO2 gas supply port 154b of the second carbonation curing section 152b and the valve 166 of the CO2 gas outlet 156a of the first carbonation curing section 152a are opened. This creates a flow path in which gas containing CO2 is supplied from the CO2 gas supply port 154b of the second carbonation curing section 152b, gas containing CO2 is supplied through the flow path of the second carbonation curing section 152b, the third carbonation curing section 152c, the fourth carbonation curing section 152d, and the first carbonation curing section 152a, and the gas is discharged from the CO2 gas outlet 156a of the first carbonation curing section 152a. By using this distribution route, CO2-containing gas can be supplied from concrete 162b, which has a high degree of carbonation curing, to concrete 162e, which has a low degree of carbonation curing, thus enabling effective use of CO2 and improving reaction efficiency.

[0049] According to the carbonation curing system and method of the present invention, by contacting concrete with a high CO2 concentration gas with a high degree of carbonation curing progress and concrete with a low CO2 concentration gas with a low degree of carbonation curing progress, it is possible to perform carbonation curing of concrete with high reaction efficiency and shorten the curing time. [Industrial applicability]

[0050] The carbonation curing system and method of the present invention have a short reaction time and a high reaction rate, allowing for more efficient curing, and the resulting hardened material can be suitably used in the civil engineering and construction fields, among others. [Explanation of symbols]

[0051] 10, 50, 110, 150 Carbonation Curing System 12a, 12b, 12c, 112a, 112b, 112c, 112d Carbonation curing tank 14, 54, 114a, 114b, 114c, 114d, 154a, 154b, 154c, 154d CO2 gas supply port 16, 56, 116a, 116b, 116c, 116d, 156a, 156b, 156c, 156d CO2 gas outlet 18 58 118 158 Gas Distribution Department 20, 60 Conveying mechanism 22a, 22b, 22c, 22d, 62a, 62b, 62c, 62d, 122a, 122b, 122c, 122d, 122e, 162a, 162b, 162c, 162d, 162e Concrete 24 Operating Doors 51, 151 Carbonation curing tank 52a, 52b, 52c, 152a, 152b, 152c, 152d Carbonation curing section 126, 166 valves 153 Wall

Claims

1. A carbonation curing system used in the manufacture of concrete, At least two or more carbonation curing sections, A CO2 filter is provided between each of the aforementioned carbonation curing sections, between the aforementioned carbonation curing sections. ２ A gas distribution section that distributes gas containing, CO ２ CO2, which supplies gas containing CO2 ２ Gas supply port and CO from the system ２ CO2 with reduced gas ２ CO2 emissions gas containing CO2 ２ Equipped with a gas outlet, The CO ２ gas supply port is provided in at least one of the carbonation curing parts, and the CO ２ gas discharge port is provided in at least one of the carbonation curing parts different from the carbonation curing part where the CO ２ gas supply port is provided. Each of the aforementioned carbonation curing sections is provided with concrete undergoing different stages of carbonation curing. The gas flow section is the CO ２ The gas containing the CO ２ A gas distribution section capable of supplying gas along a gas distribution path, such that the concrete undergoes a high degree of carbonation curing progresses from concrete with a high degree of carbonation curing to concrete with a low degree of carbonation curing. A carbonation curing system comprising: a removal mechanism for removing concrete after carbonation curing is complete; a transport mechanism for transporting concrete from the carbonation curing section downstream of the CO2-containing gas flow path to the carbonation curing section upstream; and an installation mechanism for installing uncured concrete in the carbonation curing section at the downstream end of the flow path.

2. A carbonation curing system used in the manufacture of concrete, At least two or more carbonation curing sections, A gas circulation section is provided between each of the carbonation curing sections, and a gas containing CO2 is circulated between the carbonation curing sections. The system comprises a CO2 gas supply port for supplying gas containing CO2, and a CO2 gas outlet for discharging gas containing CO2 with reduced CO2 concentration from the system. Each of the carbonation curing sections is supplied with the CO ２ Gas supply port, and the CO ２ A gas outlet is provided, and the CO ２ Gas supply port, and the CO ２ The gas outlet is the CO ２ The carbonation curing section that supplies a gas containing CO, and the CO ２ CO2 with reduced gas ２ The system includes a valve that changes the carbonation curing section from which a gas containing the gas is discharged, Each of the aforementioned carbonation curing sections is equipped with a concrete installation mechanism and a concrete removal mechanism that can install concrete undergoing different stages of carbonation curing. The gas distribution unit is a gas distribution unit capable of supplying the CO2-containing gas along the gas distribution path so that the concrete progresses from a high degree of carbonation curing to a low degree of carbonation curing. The removal mechanism is a removal mechanism for removing concrete after carbonation curing has been completed, and the installation mechanism is an installation mechanism for installing uncured concrete in the carbonation curing section from which the concrete has been removed. The aforementioned valve is the CO ２ A gas distribution route including CO2, wherein the gas containing CO2 is supplied from the downstream carbonation curing section adjacent to the carbonation curing section where uncured concrete is installed, and the CO2 ２ CO2 with reduced gas ２ A carbonation curing system comprising a valve for changing the discharge of gas containing a certain substance to be carried out from the carbonation curing section where uncured concrete is installed.

3. A carbonation curing method used in the manufacture of concrete, The carbonation curing section has concrete with different stages of carbonation curing, CO2 ２ A carbonation curing method that involves supplying a gas containing [a specific gas].

4. After the carbonation curing is complete, remove the concrete from the carbonation curing section. The aforementioned CO ２ The carbonation curing method according to claim 3, comprising transporting the concrete of the carbonation curing section downstream of the gas flow path containing the gas to the carbonation curing section upstream, and installing uncured concrete in the carbonation curing section at the downstream end of the flow path.

5. The concrete that has completed the carbonation curing is removed from the carbonation curing section, and uncured concrete is placed in the carbonation curing section. The aforementioned CO ２ The supply of gas containing the CO ２ A gas distribution route including CO2, supplied from the downstream carbonation curing section adjacent to the carbonation curing section where uncured concrete is installed, ２ CO2 with reduced gas ２ The carbonation curing method according to claim 3, wherein the discharge of gas containing is performed from the carbonation curing section where uncured concrete is installed.

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