Carbonation curing management method for hydraulic hardened body and carbonation curing system for hydraulic hardened body

Abstract

To provide a carbonation aging management method of a hydraulic hardened body and a carbonation aging system of the hydraulic hardened body, capable of efficiently using CO2 in a carbonation aging tank for carbonation aging of the hydraulic hardened body by reducing the amount of the CO2 leaked from the carbonation aging tank without being used for the carbonation aging of the hydraulic hardened body.SOLUTION: A carbonation curing control method for a hydraulic hardened body includes a filling step of filling a carbonation curing tank for storing a hydraulic hardened body with a carbon dioxide-containing gas having a higher CO2 concentration than air, a curing step of subjecting the hydraulic hardened body to carbonation curing with the carbon dioxide filled in the carbonation curing tank in the filling step, and a discharging step of discharging a gas containing at least carbon dioxide from the inside of the carbonation curing tank to the outside of the carbonation curing tank after the curing step. In the filling step, the curing step, and the discharging step, control is performed under conditions different from each other and according to each step.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for managing carbonation curing of a hydraulically hardened body and a carbonation curing system for a hydraulically hardened body. [Background technology]

[0002] In recent years, technology for fixing CO2 in concrete has been attracting a great deal of attention in order to realize a carbon-neutral society. In this technology, the CO2 concentration in the tank is increased, and carbonation curing is carried out during the hardening process of the concrete left in the tank, causing the concrete to absorb and fix CO2.

[0003] For example, Patent Document 1 describes a curing system for producing a concrete-based final product and curing a material that will not fully cure without the presence of CO2. In the curing system of Patent Document 1, the bonding element has a core containing a predetermined element, a first layer at least partially covering the core and containing the predetermined element, and a second layer at least partially covering the first layer and containing the predetermined element. Carbon dioxide gas is supplied to the curing chamber from a carbon dioxide source via a gas inlet port, and during curing, the concentration of carbon dioxide gas in the curing chamber, the temperature of the carbon dioxide gas, the humidity of the carbon dioxide gas, the amount of carbon dioxide gas supplied to the curing chamber, and the circulation of carbon dioxide gas present in the curing chamber are controlled.

[0004] However, in conventional carbonation curing systems such as those described in Patent Document 1, not all of the CO2 already present in the curing chamber before the CO2 supply and the CO2 supplied to the curing chamber are used for carbonation curing, and the CO2 not used for carbonation curing leaks from the curing chamber. As such, the CO2 in the curing chamber is not fully used for carbonation curing and is wasted and released from the curing chamber. Therefore, there is a need to increase the amount of CO2 used for carbonation curing in the curing chamber and reduce the amount of CO2 leaking from the curing chamber. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6598818 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a method for managing the carbonation curing of a hydraulic hardened body and a carbonation curing system for a hydraulic hardened body, which can reduce the amount of CO2 leaking from the carbonation curing tank without being used for the carbonation curing of the hydraulic hardened body, thereby allowing the CO2 in the carbonation curing tank to be used efficiently for the carbonation curing of the hydraulic hardened body. [Means for solving the problem]

[0007] [1] A method for managing the carbonation curing of a hydraulically hardened body, comprising: a filling step of filling a carbon dioxide-containing gas having a higher CO2 concentration than air into a carbonation curing tank that contains a hydraulically hardened body; a curing step of carbonating and curing the hydraulically hardened body with the carbon dioxide gas filled into the carbonation curing tank in the filling step; and a discharging step of discharging gas containing at least carbon dioxide gas from the inside of the carbonation curing tank to the outside of the carbonation curing tank after the curing step, wherein the filling step, the curing step, and the discharging step are performed under different conditions and are controlled according to each step. [2] The carbonation curing management method for a hydraulic hardened body according to the above item [1], wherein the filling step comprises a first filling step of filling the carbon dioxide-containing gas without stirring the gas in the carbonation curing tank, and a second filling step, which is carried out after the first filling step, of stirring the gas in the carbonation curing tank and then filling the carbon dioxide-containing gas. [3] The carbonation curing management method for a hydraulic hardened body according to [1] or [2] above, wherein in the curing step, a unidirectional airflow is generated in the carbonation curing tank to continuously expose the surface of the hydraulic hardened body to a gas containing CO2. [4] In the curing process, when the differential pressure P (P = P1 - P2) between the internal pressure P1 and the external pressure P2 of the carbonation curing tank satisfies P ≤ 0, the valve at the discharge part of the carbonation curing tank is closed, and the carbon dioxide-containing gas is supplied into the carbonation curing tank, and Mode 1 is performed. The method for managing carbonation curing of a hydraulic hardened body according to any one of [1] to [3] above. [5] In the curing process, when the differential pressure P (P = P1 - P2) between the internal pressure P1 and the external pressure P2 of the carbonation curing tank satisfies P > 0 and the offset value P3 used as the allowable internal pressure of the carbonation curing tank satisfies P < P3, the valve at the discharge part of the carbonation curing tank is closed, and the carbon dioxide-containing gas is supplied into the carbonation curing tank at a supply rate slower than that in Mode 1, and Mode 2 is performed. The method for managing carbonation curing of a hydraulic hardened body according to [4] above. [6] In the curing process, when the differential pressure P (P = P1 - P2) between the internal pressure P1 and the external pressure P2 of the carbonation curing tank satisfies P > 0 and the offset value P3 used as the allowable internal pressure of the carbonation curing tank satisfies P > P3, the valve at the discharge part of the carbonation curing tank is opened to discharge the gas to the outside of the carbonation curing tank, and then the valve is closed, and Mode 3 is performed. The method for managing carbonation curing of a hydraulic hardened body according to any one of [1] to [5] above. [7] The method for managing carbonation curing of the hydraulic hardened body includes a plurality of carbonation curing tanks, the carbonation curing tanks are connected to each other, and a gas containing at least carbon dioxide discharged to the outside of the carbonation curing tank is supplied into another carbonation curing tank. The method for managing carbonation curing of a hydraulic hardened body according to any one of [1] to [6] above. [8] A carbonation curing system for a hydraulically hardened body, comprising: a carbonation curing tank for accommodating a hydraulically hardened body; a supply unit for supplying a carbon dioxide-containing gas having a CO2 concentration higher than that of air into the carbonation curing tank; and a discharge unit for discharging a gas containing at least carbon dioxide from the interior of the carbonation curing tank to the outside of the carbonation curing tank, wherein the filling process of the carbon dioxide-containing gas involves supplying the carbon dioxide-containing gas into the carbonation curing tank and filling it; the curing process of the hydraulically hardened body involves carbonation curing the hydraulically hardened body with the carbon dioxide gas filled in the carbonation curing tank; and the discharging process of the gas containing at least carbon dioxide involves discharging the gas containing at least carbon dioxide to the outside of the carbonation curing tank after curing the hydraulically hardened body, and the filling process, the curing process, and the discharging process are performed under different conditions, and are controlled according to each process. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for managing the carbonation curing of a hydraulic hardened body and a carbonation curing system for a hydraulic hardened body, which can efficiently use the CO2 in the carbonation curing tank for the carbonation curing of the hydraulic hardened body by reducing the amount of CO2 that leaks from the carbonation curing tank without being used for the carbonation curing of the hydraulic hardened body. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart showing a flow of a method for managing carbonation curing of a hydraulically hardened body according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing a preferred control flow of the curing process constituting the carbonation curing management method for a hydraulically hardened body according to the embodiment. [Figure 3] FIG. 3 is a schematic diagram showing a preferred example of the carbonation curing management method for a hydraulically hardened body according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of a carbonation curing system for a hydraulically hardened body according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a detailed description will be given based on an embodiment.

[0011] As a result of extensive research into carbonation curing methods for hydraulic hardened bodies, the inventors have discovered that a method for carbonation curing a hydraulic hardened body, which comprises a filling step of filling a carbon dioxide-containing gas, a curing step of carbonation curing the hydraulic hardened body, and a discharging step of discharging a gas containing at least carbon dioxide, can be achieved by controlling the filling step, curing step, and discharging step under different conditions depending on the step, thereby reducing the amount of CO2 leaking from the carbonation curing tank without being used for the carbonation curing of the hydraulic hardened body, and allowing the CO2 in the carbonation curing tank to be used efficiently for the carbonation curing of the hydraulic hardened body. This discovery led to the completion of the present invention.

[0012] The carbonation curing management method for a hydraulically hardened body of the present invention comprises a filling step of filling a carbon dioxide-containing gas having a higher CO2 concentration than air into a carbonation curing tank containing the hydraulically hardened body, a curing step of carbonation curing the hydraulically hardened body with the carbon dioxide gas filled into the carbonation curing tank in the filling step, and a discharging step of discharging the gas containing at least carbon dioxide from the carbonation curing tank to the outside after the curing step. The filling step, curing step, and discharging step are performed under different conditions and under control appropriate for each step.

[0013] The carbonation curing system for a hydraulically hardened body of the present invention comprises a carbonation curing tank for accommodating the hydraulically hardened body, a supply unit for supplying a carbon dioxide-containing gas having a higher CO2 concentration than air into the carbonation curing tank, and a discharge unit for discharging the gas containing at least carbon dioxide from the carbonation curing tank to the outside. In the carbon dioxide-containing gas filling process, the carbon dioxide-containing gas is supplied to the carbonation curing tank to fill it, in the hydraulically hardened body curing process, the hydraulically hardened body is carbonation-cured using the carbon dioxide gas filled in the carbonation curing tank, and in the carbon dioxide-containing gas discharge process, the gas containing at least carbon dioxide is discharged to the outside of the carbonation curing tank after curing of the hydraulically hardened body. The filling process, curing process, and discharge process are performed under different conditions and are controlled according to each process.

[0014] Fig. 1 is a flowchart showing a flow of a carbonation curing management method for a hydraulically hardened body according to an embodiment. As shown in Fig. 1, the carbonation curing management method for a hydraulically hardened body includes a filling step S10, a curing step S20, and a discharging step S30. The filling step S10, the curing step S20, and the discharging step S30 are performed under different conditions and under control appropriate for each step.

[0015] In the filling step S10, a carbon dioxide-containing gas having a higher CO2 concentration than air is filled into a carbonation curing tank containing the hydraulic hardened body. The carbon dioxide-containing gas is a gas containing carbon dioxide, and preferably consists of only carbon dioxide. The CO2 concentration in the carbon dioxide-containing gas is higher than the CO2 concentration in air. The hydraulic hardened body is the object of carbonation curing in the curing step S20 described below, and can absorb and fix CO2 by carbonation curing (hereinafter, absorption and fixation are also referred to as fixation). The carbonation curing tank is, for example, a shipping container.

[0016] The hydraulic hardened material contains cement and hardens by reacting with water, and examples thereof include concrete and mortar. In the curing step S20 described below, the hydraulic hardened material undergoes carbonation curing, in which the hydraulic hardened material reacts with carbon dioxide gas during the hardening process, thereby fixing CO2 in the hydraulic hardened material.

[0017] In the filling step S10, it is preferable to fill the carbon dioxide-containing gas from the bottom of the carbon dioxide-containing tank 2 in order to reduce the amount of CO2 that leaks from the carbon dioxide-containing tank without being used for the carbonation curing of the hydraulic hardened body and to efficiently use the carbon dioxide in the carbon dioxide-containing gas for the carbonation curing of the hydraulic hardened body.

[0018] Although the curing step S20 described below is the main step of carbonation curing the hydraulic hardened body, carbonation curing of the hydraulic hardened body may also occur in the filling step S10. In this case, the degree of carbonation curing in the filling step S10 is smaller than the degree of carbonation curing in the curing step S20.

[0019] The filling step S10 includes a first filling step S11 in which a carbon dioxide-containing gas is filled into the carbonation curing tank without stirring the gas in the carbonation curing tank, and a second filling step S12 which is carried out after the first filling step S11 and in which the gas in the carbonation curing tank is stirred and then the carbon dioxide-containing gas is filled into the carbonation curing tank.

[0020] In the first filling step S11, the carbon dioxide-containing gas is filled into the carbonation curing tank without stirring. Furthermore, the air conditioning equipment is not operated during the first filling step S11. In this way, in the first filling step S11, the carbon dioxide-containing gas is statically filled into the carbonation curing tank without stirring, which makes it easier for carbon dioxide to accumulate in the lower part of the carbonation curing tank. This actively creates a difference in CO2 concentration between the top and bottom of the carbonation curing tank, where the CO2 concentration in the lower part of the carbonation curing tank is higher than the CO2 concentration in the upper part of the carbonation curing tank. In this state, the gas with a low CO2 concentration occupying the upper part of the carbonation curing tank is discharged to the outside of the carbonation curing tank without stirring the carbonation curing tank. This completes the first filling step S11.

[0021] In the first filling step S11, gas with a high CO2 concentration that has accumulated in the lower part of the carbonation curing tank is not discharged to the outside of the carbonation curing tank. Furthermore, in the first filling step S11, the carbonation curing tank is stirred while the carbon dioxide-containing gas is being filled to homogenize the CO2 concentration in the carbonation curing tank, and the gas with the homogenized CO2 concentration is not discharged to the outside of the carbonation curing tank. This prevents unnecessary release of carbon dioxide from the carbonation curing tank. Note that the gas occupying the lower part of the carbonation curing tank when the carbonation curing tank is not stirred in the first filling step S11 has a higher CO2 concentration than the gas with the homogenized CO2 concentration in the carbonation curing tank.

[0022] In this way, in the first filling step S11, by filling the carbon dioxide-containing gas without operating the air conditioning equipment, it is possible to easily create a state in which the carbon dioxide gas in the carbonation curing tank is not mixed with gases other than carbon dioxide gas. Therefore, the CO2 concentration in the carbonation curing tank can be easily controlled to a desired value or higher in a short period of time. Furthermore, because the air conditioning equipment is not operated, the gas with a low CO2 concentration occupying the upper part is not air-conditioned, and unnecessary power consumption can be avoided when discharging it outside the carbonation curing tank.

[0023] From the viewpoint of reducing the amount of carbon dioxide gas leaking from the carbonation curing tank, it is preferable to discharge the gas containing carbon dioxide gas from the upper part of the carbonation curing tank when the ratio of the CO2 concentration in the upper part of the carbonation curing tank to the CO2 concentration in the lower part of the carbonation curing tank (CO2 concentration in the upper part / CO2 concentration in the lower part) is 0.4 or less. It is even more preferable to reduce the CO2 concentration ratio to 0.1 or less by slowing the filling rate of the gas containing carbon dioxide gas to 100 liters / minute or less as long as time allows.

[0024] In the second filling step S12 carried out after the first filling step S11, the carbon dioxide-containing gas is again filled in after stirring the inside of the carbonation curing tank. In addition, in the second filling step S12, the air conditioning equipment is not operated.

[0025] First, in the second filling step S12, the gas in the carbonation curing tank is stirred while the filling of the carbon dioxide-containing gas is stopped to homogenize the CO2 concentration in the carbonation curing tank. By stirring the gas in the carbonation curing tank in this way, the CO2 concentration, temperature, and humidity in the carbonation curing tank can be accurately measured regardless of the locations of the CO2 concentration sensor, temperature sensor, and humidity sensor installed in the carbonation curing tank. This makes it easy to grasp the overall condition in the carbonation curing tank, and efficiently control the carbonation curing tank to achieve the desired carbonation curing conditions.

[0026] For example, in the first filling step S11, carbon dioxide-containing gas is filled into the carbonation curing tank until the CO2 input amount matches the desired CO2 concentration, taking into consideration the volume of the carbonation curing tank and the filling speed of the carbon dioxide-containing gas. Then, in the second filling step S12, the carbonation curing tank is stirred so that the values ​​of the sensors at various locations, such as the CO2 concentration, match or nearly match the desired values.

[0027] The gas in the carbonation curing tank is agitated by a blower installed inside the tank. The blower agitates the gas in the carbonation curing tank, and is different from the air conditioning equipment that adjusts the temperature and humidity inside the carbonation curing tank. However, in addition to the blower, the air conditioning function of the air conditioning equipment can be turned off and only the blowing function can be used to agitate the gas more efficiently.

[0028] In the second filling step S12, after the CO2 concentration in the carbonation curing tank is homogenized and stirring in the carbonation curing tank is completed, the carbon dioxide-containing gas is again filled into the carbonation curing tank. Then, after the CO2 concentration in the carbonation curing tank reaches a desired value, the filling of the carbon dioxide-containing gas is stopped. In this way, the second filling step S12 is completed.

[0029] In the curing step S20 carried out after the filling step S10, the hydraulic hardened body is carbonation cured by the carbon dioxide gas filled into the carbonation curing tank in the filling step S10. In this way, a hydraulic hardened body in which the carbon dioxide gas is fixed can be obtained.

[0030] In the curing step S20, the air conditioning equipment is operated to generate a unidirectional airflow in the carbonation curing tank, and the airflow containing CO2 is continuously applied to the surface of the hydraulically hardened body. The unidirectional airflow in the carbonation curing tank can be generated, for example, by a blower, and the air supply duct and air intake of the air conditioning equipment installed in the carbonation curing tank.

[0031] The air conditioning equipment intake is located on the side of the carbonation curing tank opposite the air blower. The air supply duct intake is located around the air blower and faces the blower. The hydraulic hardened body is installed between the opposing air supply duct intake and the air conditioning equipment intake. In this way, the air supply duct and the air conditioning equipment intake are located separately.

[0032] Gas containing CO2, the temperature and humidity of which has been adjusted by the operating air conditioning equipment, is released toward the fan from the air outlet of the air supply duct installed at the top of the carbonation curing tank. The fan then blows the temperature- and humidity-adjusted gas toward the air conditioning equipment intake port installed beyond the hydraulic hardened body. As the temperature- and humidity-adjusted gas flows toward the air conditioning equipment intake port, it comes into contact with the hydraulic hardened body, accelerating the carbonation curing of the hydraulic hardened body and generating water vapor from the hydraulic hardened body.

[0033] After coming into contact with the hydraulically hardened body, the CO2 concentration of the gas decreases and the humidity increases. The gas with a decreased CO2 concentration and increased humidity is drawn into the air conditioning equipment intake, along with gases that have at least one of a higher CO2 concentration and a lower humidity than the original gas. Furthermore, when carbon dioxide-containing gas is supplied to the carbonation curing tank, air with a higher CO2 concentration than the gas with a decreased CO2 concentration and increased humidity is also drawn into the air conditioning equipment intake. The air drawn in through the intake is sent to the air conditioning equipment, which adjusts the temperature and humidity and mixes gases with different CO2 concentrations. The air, whose temperature and humidity have been adjusted by the air conditioning equipment and whose CO2 concentration is maintained, is then released again through the air supply duct's air supply port toward the blower.

[0034] In this way, the gas, whose temperature and humidity have been adjusted and whose CO2 concentration has been maintained, is forced to continuously contact the surface of the hydraulically cured body as the unidirectional airflow. This prevents airflow turbulence, stagnant gas, and localized airflow loops due to the placement of the hydraulically cured body. This allows for efficient use of CO2 in the carbonation curing tank, enabling efficient carbonation curing of the hydraulically cured body with minimal unevenness. Furthermore, because the air supply duct's air outlet and the air conditioning equipment's air intake are positioned opposite each other, the unidirectional airflow allows water vapor generated from the hydraulically cured body during carbonation curing to be efficiently drawn into the air conditioning equipment through the downstream intake. As a result, dehumidification efficiency within the carbonation curing tank is improved.

[0035] That is, in the curing process S20, the air conditioning equipment adjusts the temperature, humidity and CO2 concentration, the blower blows the gas whose temperature, humidity and CO2 concentration have been adjusted by the air conditioning equipment onto the hydraulic hardened body, the hydraulic hardened body is carbonation cured with the gas whose temperature, humidity and CO2 concentration have been adjusted, the blower blows the gas after carbonation curing to the air conditioning equipment, and the air conditioning equipment adjusts the temperature, humidity and CO2 concentration of the gas blown by the blower, and this cycle is carried out continuously and forcibly.

[0036] The curing step S20 preferably follows the control flow below: Figure 2 is a flowchart showing a suitable control flow for the curing step S20.

[0037] As shown in FIG. 2, first, an offset value P3 is set for the differential pressure sensor as the allowable internal pressure of the carbonation curing tank. The offset value P3 can be set appropriately depending on the internal volume of the carbonation curing tank. The maximum value of the offset value P3 (MPa) is 0.004 / internal volume of the carbonation curing tank (m 3 ) or less (maximum value of offset value P3≦0.004 / internal volume of carbonation curing tank). The differential pressure sensor measures the differential pressure P (P=P1−P2) between the internal pressure P1 of the carbonation curing tank and the external pressure P2 (atmospheric pressure) of the carbonation curing tank.

[0038] Next, in order to reduce the amount of CO2 leaking from the carbonation curing tank without being used for the carbonation curing of the hydraulic hardened body and to efficiently use the CO2 in the carbonation curing tank for the carbonation curing of the hydraulic hardened body, a mode is determined based on the measurement value of the differential pressure sensor and offset value P3, and the following mode 1, mode 2, or mode 3 is selected. In this way, the differential pressure sensor determines the control mode at that time.

[0039] In mode 1, when the measurement result of the differential pressure sensor is P≦0, the valve at the discharge part of the carbonation curing tank (preferably the overflow valve 41a described later) is closed, and carbon dioxide-containing gas is supplied into the carbonation curing tank. In mode 1, as the carbonation curing of the hydraulically hardened body progresses, carbon dioxide is fixed in the hydraulically hardened body, and a volume of gas equivalent to the amount of fixed carbon dioxide is lost from the carbonation curing tank. To compensate for this pressure drop (decompression), carbon dioxide-containing gas is supplied to the carbonation curing tank. Therefore, the CO2 concentration in the carbonation curing tank at the start of the curing step S20 can be roughly maintained.

[0040] Because the internal pressure P1 of the carbonation curing tank is equal to or less than the external pressure P2 of the carbonation curing tank, even if a carbon dioxide-containing gas is supplied into the carbonation curing tank, no carbon dioxide will leak out of the carbonation curing tank. In this way, in Mode 1, CO2 lost through carbonation curing continues to be supplied to the carbonation curing tank, so the internal pressure P1 of the carbonation curing tank never exceeds the external pressure P2, and the amount of CO2 leaking from the carbonation curing tank can be reduced.

[0041] Furthermore, in a configuration in which the opening and closing of the valve at the discharge part of the carbonation curing tank is controlled in conjunction with the pressure measured by the differential pressure sensor, controlling the valve at the discharge part of the carbonation curing tank to open when the differential pressure P is −300 Pa or less can prevent damage to sealing materials such as packing that constitute the valve at the discharge part of the carbonation curing tank, and can prevent pressure abnormalities inside the carbonation curing tank that would be caused by damage to the sealing materials.

[0042] In mode 2, when the measurement result of the differential pressure sensor is differential pressure P>0 and differential pressure P<offset value P3, the valve at the discharge part of the carbonation curing tank is closed and carbon dioxide-containing gas is supplied into the carbonation curing tank, but the supply rate of the carbon dioxide-containing gas can be set lower than in mode 1. As the carbonation curing of the hydraulically hardened body progresses, carbon dioxide is fixed in the hydraulically hardened body, and a volume of gas equivalent to the amount of fixed carbon dioxide is lost from the carbonation curing tank, causing a drop in internal pressure, and an increase in internal pressure due to increases in temperature and humidity inside the carbonation curing tank, and the generation of moisture from the hydraulically hardened body (water vapor pressure), etc.

[0043] Because the differential pressure P is smaller than the offset value P3, which is the allowable internal pressure of the carbonation curing tank, the internal pressure of the carbonation curing tank is within the allowable range. Therefore, in Mode 2, CO2 leakage due to the opening of the discharge valve of the carbonation curing tank is prevented, and carbon dioxide-containing gas is supplied at a lower supply rate than in Mode 1, thereby enabling efficient carbonation curing.

[0044] In mode 3, when the measurement results of the differential pressure sensor are such that the differential pressure P>0 and the differential pressure P>offset value P3, the valve of the discharge part of the carbonation curing tank is opened to discharge the gas inside the carbonation curing tank 2 to the outside of the carbonation curing tank 2, and then the valve of the discharge part of the carbonation curing tank is closed. In mode 3, the internal pressure of the carbonation curing tank increases further than in mode 2, and the pressure resistance of the carbonation curing tank becomes unacceptable. Therefore, the valve of the discharge part of the carbonation curing tank is opened to discharge the gas inside the carbonation curing tank and reduce the internal pressure to an allowable level, and then the valve of the discharge part of the carbonation curing tank is closed again. Alternatively, a carbon dioxide-containing gas may be supplied into the carbonation curing tank after that.

[0045] In this way, in Mode 3, by temporarily opening the valve at the discharge part of the carbonation curing tank, the pressure-resistant unacceptable state of the carbonation curing tank can be quickly resolved while minimizing the amount of carbon dioxide gas leakage.

[0046] Furthermore, if the curing of the hydraulically hardened body is not completed, this control mode is repeated.

[0047] If carbon dioxide-containing gas is not supplied to the carbonation curing tank when the differential pressure sensor's measurement result is P≦0, the internal pressure of the carbonation curing tank will drop, causing air outside the tank to be drawn in through gaps in the sealant, such as the packing, that makes up the valve at the carbonation curing tank's outlet, potentially resulting in a decrease in the CO2 concentration inside the carbonation curing tank. Furthermore, if carbon dioxide-containing gas is supplied to the carbonation curing tank regardless of the carbonation curing tank's differential pressure P, the internal pressure of the carbonation curing tank will rise, forcing CO2-containing gas out of the tank through gaps in the sealant that makes up the valve at the carbonation curing tank's outlet, resulting in wasted CO2. Therefore, these problems can be solved by using modes 1 to 3 to perform control according to the carbonation curing tank's differential pressure P.

[0048] In this way, the above control flow measures the differential pressure P in the carbonation curing tank and controls the curing step S20 based on the measured differential pressure P, thereby reducing the amount of CO2 leaking from the carbonation curing tank.

[0049] Furthermore, by performing the filling process S10 and the curing process S20 separately, it is possible to reduce the unnecessary release of CO2 from the carbonation curing tank and also reduce the amount of electricity consumed by air conditioning equipment such as heating, cooling, and dehumidification.

[0050] In the discharge step S30 performed after the curing step S20, gas containing at least carbon dioxide gas that was not used in the carbonation curing of the hydraulic hardened body in the curing step S20 is discharged from the inside of the carbonation curing tank to the outside of the carbonation curing tank.

[0051] In the discharge step S30, gas containing at least carbon dioxide gas is discharged to the outside of the carbonation curing tank to an extent that the safety of the worker can be ensured even if the worker enters the carbonation curing tank, and further, the carbonation curing tank is ventilated as necessary to reduce the CO2 concentration in the carbonation curing tank.

[0052] Fig. 3 is a schematic diagram showing a preferred example of the carbonation curing management method for a hydraulically hardened body according to the embodiment. Note that the schematic diagram in Fig. 3 is simplified.

[0053] When the CO2 concentration of the gas discharged in the carbonation curing tank discharging step S30 is higher than that of air, the carbonation curing management method for hydraulic hardened body H preferably comprises connecting multiple carbonation curing tanks 2 (21, 22) and supplying the gas containing at least carbon dioxide gas discharged to the outside of carbonation curing tank 21 into carbonation curing tank 22 separate from carbonation curing tank 21 from which the gas was discharged, as shown in Figure 3. The separate carbonation curing tank 22 has a configuration similar to that of the above-mentioned carbonation curing tank 21, and can perform the filling step S10, curing step S20, and discharging step S30.

[0054] Carbon dioxide-containing gas, which is discharged outside the carbonation curing tank 21 from an exhaust section 91 having an exhaust valve 91a and an exhaust fan 92 and has a higher CO2 concentration than air, is charged into a separate carbonation curing tank 22 from an intake section 93 having an intake three-way valve 93b, so that the CO2 discharged from the carbonation curing tank 21 can be reused for carbonation curing of the hydraulic hardened body H contained in the separate carbonation curing tank 22. This further reduces the amount of CO2 leaking from the carbonation curing tank without being used for carbonation curing of the hydraulic hardened body.

[0055] Furthermore, when the CO2 concentration of the gas discharged from the carbonation curing tank 22 is higher than that of air, the carbon dioxide-containing gas discharged from the exhaust section 91 of the carbonation curing tank 22 can be filled into the carbonation curing tank 21 through the intake three-way valve 93b of the intake section 93, thereby further reducing the amount of CO2 leaking from the carbonation curing tank without being used for carbonation curing of the hydraulic hardened body.

[0056] When the carbonation curing tanks 21, 22 take in outside air, the intake three-way valve 93b is switched to the outside side. When multiple carbonation curing tanks 21, 22 are not connected, the intake three-way valve 93b is replaced with an intake valve 93a, which is a two-way valve and will be described later.

[0057] Next, a carbonation curing system for a hydraulically hardened body according to an embodiment will be described.

[0058] 4 is a schematic diagram showing an example of a carbonation curing system for a hydraulic hardened body according to an embodiment. The carbonation curing system for a hydraulic hardened body according to an embodiment is a system for performing the carbonation curing management method for a hydraulic hardened body according to the embodiment.

[0059] As shown in Figure 4, the carbonation curing system 1 for hydraulically hardened bodies includes a carbonation curing tank 2 that accommodates a hydraulically hardened body H, a supply unit 3 that supplies a carbon dioxide-containing gas having a higher CO2 concentration than air into the carbonation curing tank 2, and a discharge unit 41 that discharges the gas containing at least carbon dioxide from the inside of the carbonation curing tank 2 to the outside of the carbonation curing tank 2. For example, the hydraulically hardened body H is placed on a support 5 such as a block timber. In the carbonation curing system 1 for hydraulic hardened bodies, in the carbon dioxide-containing gas filling process, the carbon dioxide-containing gas is supplied and filled into the carbonation curing tank 2, and in the curing process for the hydraulic hardened body H, the hydraulic hardened body H is carbonation-cured with the carbon dioxide gas filled into the carbonation curing tank 2, and in the gas discharge process containing at least carbon dioxide, the gas containing at least carbon dioxide is discharged to the outside of the carbonation curing tank 2 after curing of the hydraulic hardened body H, and the carbon dioxide-containing gas filling process, the hydraulic hardened body curing process, and the gas discharge process are performed under different conditions and are controlled according to each process.

[0060] The filling process, curing process, and discharge process in the carbonation curing system 1 for hydraulically hardened bodies correspond to the filling step S10, curing step S20, and discharge step S30, respectively, in the carbonation curing management method for hydraulically hardened bodies of the above embodiment.

[0061] The carbonation curing system 1 also includes a blower 6 for agitating the gas inside the carbonation curing tank 2, a differential pressure sensor 7 for measuring the pressure difference P between the internal pressure P1 and external pressure P2 of the carbonation curing tank 2, and an air conditioning unit 8 provided inside the carbonation curing tank 2. For example, the blower 6 is provided at a position opposite the supply unit 3, and blows air in a direction away from the carbon dioxide delayed discharge mechanism 4. An air supply duct 81 of the air conditioning unit 8 is provided inside the carbonation curing tank 2, and an intake port 8a of the air conditioning unit 8 is located inside the carbonation curing tank 2.

[0062] The carbonation curing system 1 for hydraulically hardened bodies preferably has the following configuration.

[0063] The supply unit 3 supplies a carbon dioxide-containing gas from the outside of the carbonation curing tank 2 to the inside of the carbonation curing tank 2 through a supply opening 2a provided in the side wall of the carbonation curing tank 2. The supply unit 3 is provided with a supply valve 3a and is connected to a CO2 supply device 3b. The CO2 supply device 3b supplies the carbon dioxide-containing gas to the supply unit 3. If necessary, the CO2 concentration, temperature, CO2 supply rate, etc. of the carbon dioxide-containing gas supplied from the CO2 supply device 3b to the supply unit 3 may be adjusted by an adjustment unit (not shown).

[0064] The carbon dioxide-containing gas supplied from the CO2 supply equipment 3b to the supply unit 3 is supplied from the supply unit 3 to the inside of the carbonation curing tank 2. The supply valve 3a of the supply unit 3 controls the stop and start of supply (supply restart) of the carbon dioxide-containing gas into the carbonation curing tank 2, as well as the adjustment of the supply amount of the carbon dioxide-containing gas supplied into the carbonation curing tank 2.

[0065] When filling the carbon dioxide-containing gas into the carbonation curing tank 2, in order to reduce the amount of CO2 that leaks from the carbonation curing tank 2 without being used for the carbonation curing of the hydraulic hardened body H and to efficiently use the carbon dioxide in the carbon dioxide-containing gas supplied from the supply unit 3 for the carbonation curing of the hydraulic hardened body H, the supply unit 3 is preferably provided in the lower part of the side wall of the carbonation curing tank 2, and more preferably in the lower part of the side wall of the carbonation curing tank 2 that faces the carbon dioxide delayed discharge mechanism 4 described below.

[0066] Furthermore, by dividing the supply unit 3 into a plurality of supply units, the carbon dioxide-containing gas is supplied separately from a plurality of positions on the lower part of the side wall of the carbonation curing tank 2, which reduces the supply rate of the carbon dioxide-containing gas per supply unit and further reduces the ratio of the CO2 concentration in the upper part of the carbonation curing tank to the CO2 concentration in the lower part of the carbonation curing tank (CO2 concentration in the upper part / CO2 concentration in the lower part), which is more preferable.

[0067] The carbonation curing system 1 for hydraulically hardened bodies includes a carbon dioxide delayed discharge mechanism 4. The carbon dioxide delayed discharge mechanism 4 discharges a gas containing at least air and carbon dioxide (hereinafter simply referred to as gas) from the inside of the carbonation curing tank 2 to the outside of the carbonation curing tank 2, and preferentially discharges air over carbon dioxide to the outside of the carbonation curing tank 2. The air contained in the gas discharged to the outside of the carbonation curing tank 2 is air that was already present inside the carbonation curing tank 2 before the carbon dioxide-containing gas was supplied from the supply unit 3, and if the carbon dioxide-containing gas supplied from the supply unit 3 contains air, the air contained in the carbon dioxide-containing gas supplied from the supply unit 3 is also included.

[0068] The carbon dioxide delayed discharge mechanism 4 utilizes the difference in weight between air and carbon dioxide gas to preferentially discharge air over carbon dioxide gas to the outside of the carbonation curing tank 2. In other words, the carbon dioxide delayed discharge mechanism 4 delays the discharge of carbon dioxide gas more than air. Furthermore, if the carbon dioxide-containing gas supplied from the supply unit 3 contains other substances in addition to carbon dioxide gas and air, the other substances are also discharged from the carbon dioxide delayed discharge mechanism 4 to the outside of the carbonation curing tank 2.

[0069] Such a carbon dioxide gas delayed discharge mechanism 4 includes a discharge part 41 and a carbon dioxide gas delay part 42.

[0070] The discharge unit 41 constituting the carbon dioxide delayed discharge mechanism 4 discharges gases including at least air and carbon dioxide from the inside of the carbonation curing tank 2 to the outside of the carbonation curing tank 2 through a discharge opening 2b provided in the side wall of the carbonation curing tank 2. The discharge unit 41 is provided in the upper part of the side wall of the carbonation curing tank 2.

[0071] An overflow valve 41a is provided in the discharge part 41. The overflow valve 41a of the carbon dioxide gas delayed discharge mechanism 4 controls the stop and start (restart) of the discharge of gas to the outside of the carbonation curing tank 2, as well as the adjustment of the amount of gas discharged to the outside of the carbonation curing tank 2.

[0072] The carbon dioxide delay unit 42 constituting the carbon dioxide delayed discharge mechanism 4 causes the gas to flow from the upper part of the carbonation curing tank 2 to the lower part thereof, and supplies the gas that has flowed upward in the carbonation curing tank 2 through a flow path cross-sectional area S2 that is smaller than the flow path cross-sectional area S1 when flowing downward, to the discharge unit 41. In the carbon dioxide delay unit 42, the flow path cross-sectional area S2 for flowing the gas from the lower part to the upper part of the carbonation curing tank 2 is smaller than the flow path cross-sectional area S1 for flowing the gas from the upper part to the lower part of the carbonation curing tank 2.

[0073] In this way, the carbon dioxide delay unit 42 utilizes the difference between the above-mentioned flow path cross-sectional area S1 and flow path cross-sectional area S2 to circulate the gas present in the upper part of the carbonation curing tank 2 downward through the flow path cross-sectional area S1, and to circulate the gas that has circulated downward through the flow path cross-sectional area S2 that is smaller than the flow path cross-sectional area S1, thereby enabling air to be supplied preferentially to the discharge unit 41 rather than carbon dioxide. In this way, the carbon dioxide delay discharge mechanism 4 can discharge air to the outside of the carbonation curing tank 2 via the discharge unit 41 preferentially rather than carbon dioxide.

[0074] The carbon dioxide gas delay section 42 having such a configuration preferably has an inner cylinder 42a and an outer cylinder 42b.

[0075] The inner cylinder 42a constituting the carbon dioxide gas delay section 42 has an upper end connected to the discharge section 41, extends downward, and is open at its lower end. The inner cylinder 42a extends up to near the inner surface of the lower end of the outer cylinder 42b.

[0076] The outer cylinder 42b that constitutes the carbon dioxide delay section 42 is closed at the bottom and extends upward, covering the outer periphery of the inner cylinder 42a from the outside. In this way, the inner cylinder 42a and the outer cylinder 42b that covers the entire periphery of the inner cylinder from the outside form a double cylinder structure.

[0077] The lower end of the inner cylinder 42a and the inner surface of the lower end of the outer cylinder 42b are not in contact with each other. For example, the lower limit of the vertical distance d between the lower end of the inner cylinder 42a and the inner surface of the lower end of the outer cylinder 42b is preferably 20 mm or more, and the upper limit is preferably 150 mm or less. If the distance d is 20 mm or more, gas can circulate smoothly even if condensation occurs between the lower ends of the inner cylinder 42a and the outer cylinder 42b. Furthermore, if the distance d is 150 mm or less, the airflow stabilization effect achieved by the length of the inner cylinder 42a and the outer cylinder 42b is satisfactory.

[0078] The lower end of the outer cylinder 42b may be connected to the bottom of the carbonation curing tank 2. When the lower end of the outer cylinder 42b is connected to the bottom of the carbonation curing tank 2, the lower end of the outer cylinder 42b may be open, and the bottom portion of the carbonation curing tank 2 connected to the lower end of the outer cylinder 42b also serves as the inner surface of the lower end of the outer cylinder 42b.

[0079] The outer cylinder 42b extends to a position lower than the upper end of the inner cylinder 42a. The upper end of the outer cylinder 42b is open.

[0080] A drain pipe 43 may be provided on the lower end side of the outer cylinder 42b to discharge a small amount of water (including condensed water) to the outside of the carbonation curing tank 2. The drain pipe 43 is provided with a drain valve 43a.

[0081] The gas flows in from the upper end of the outer cylinder 42b, flows downward through the outer cylinder 42b, then flows from the lower end of the outer cylinder 42b to the lower end of the inner cylinder 42a, flows upward through the inner cylinder 42a, and then flows into the discharge section 41 from the upper end of the inner cylinder 42a.

[0082] The cross-sectional area S2 of the flow path of the inner cylinder 42a, through which the gas flows from bottom to top, is smaller than the cross-sectional area S1 of the flow path of the outer cylinder 42b, through which the gas flows from top to bottom. With this double-cylinder structure of the inner cylinder 42a and the outer cylinder 42b, of the carbon dioxide gas and air contained in the gas in the carbonation curing tank 2, air can be supplied to the discharge part 41 preferentially over carbon dioxide gas.

[0083] From the viewpoint that the double-cylinder structure of the inner cylinder 42a and the outer cylinder 42b supplies air to the discharge section 41 with higher priority than carbon dioxide, it is preferable that the supply flow rate of the carbon dioxide-containing gas supplied from the supply section 3 to the inside of the carbonation curing tank 2 (hereinafter simply referred to as the supply flow rate of the carbon dioxide-containing gas) > the flow rate of the gas flowing upward inside the inner cylinder 42a (hereinafter simply referred to as the flow rate inside the inner cylinder 42a) > the flow rate of the gas flowing downward inside the outer cylinder 42b (hereinafter simply referred to as the flow rate inside the outer cylinder 42b), and that the flow rate inside the inner cylinder 42a is 20% or less of the supply flow rate of the carbon dioxide-containing gas, and that the flow rate inside the outer cylinder 42b is 5% or less of the supply flow rate of the carbon dioxide-containing gas. On the other hand, although the effect can be improved as the flow rate difference is increased, the size of the inner cylinder 42a and the outer cylinder 42b increases. Therefore, the flow rate difference may be appropriately selected depending on the arrangement constraints of the inner cylinder 42a and the outer cylinder 42b in the carbonation curing tank 2.

[0084] In the first half of the carbon dioxide-containing gas filling process (processing corresponding to the first filling step S11 described above), the gas in the carbonation curing tank 2 is not agitated, and instead the carbon dioxide-containing gas is supplied from the supply unit 3 provided below the carbonation curing tank 2, thereby easily creating a state in which the CO2 concentration is high below the carbonation curing tank 2 and low above the carbonation curing tank 2. Then, the gas present above the carbonation curing tank 2, i.e., the gas with a low CO2 concentration, flows into the carbon dioxide delayed discharge mechanism 4, which then actively discharges air rather than carbon dioxide out of the carbonation curing tank 2.

[0085] In this way, by statically supplying (filling) the carbon dioxide-containing gas without stirring the gas in the carbonation curing tank 2, the difference in CO2 concentration between the top and bottom of the carbonation curing tank 2 is actively increased, and the resulting gas with a low CO2 concentration above the carbonation curing tank 2 flows into the carbon dioxide delayed discharge mechanism 4, which actively discharges the air to the outside of the carbonation curing tank 2. In this way, when the carbon dioxide-containing gas is filled into the carbonation curing tank 2, the amount of CO2 leaking from the carbonation curing tank 2 without being used for the carbonation curing of the hydraulic hardened body H is reduced, thereby reducing the amount of CO2 wastedly released from the carbonation curing tank 2, and the CO2 in the carbonation curing tank 2 can be used efficiently for the carbonation curing of the hydraulic hardened body H.

[0086] The carbonation curing system 1 may further include an exhaust unit 91 having an exhaust valve 91a and an intake unit 93 having an intake valve 93a, which are provided in the carbonation curing tank 2, and an exhaust fan 92 provided in the exhaust unit 91. For example, in the discharge step S30 (discharge treatment), when it is desired to ventilate the carbonation curing tank 2, the exhaust valve 91a is opened and the exhaust fan 92 is operated to discharge the gas inside the carbonation curing tank 2 into the carbonation curing tank 2, and the intake valve 93a is opened to take in air outside the carbonation curing tank 2 into the carbonation curing tank 2. When connecting multiple carbonation curing tanks 21, 22 as described above, the intake valve 93a, which is a two-way valve, is replaced with a three-way intake valve 93b.

[0087] According to the embodiment described above, there are a filling step (filling treatment) of filling with carbon dioxide-containing gas, a curing step (curing treatment) of carbonation curing the hydraulic hardened body, and a discharging step (discharge treatment) of discharging gas containing at least carbon dioxide. The filling step, curing step, and discharging step are performed under different conditions, and control is performed according to each step (treatment), thereby reducing the amount of CO2 that leaks from the carbonation curing tank without being used for carbonation curing of the hydraulic hardened body, and allowing the CO2 in the carbonation curing tank to be used efficiently for carbonation curing of the hydraulic hardened body.

[0088] Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects encompassed by the concept and scope of the claims of the present disclosure, and can be modified in various ways within the scope of the present disclosure. [Explanation of symbols]

[0089] 1 Carbonation curing system for hydraulic hardened bodies 2, 21, 22 Carbonation curing tank 2a Supply opening 2b Ejection opening 3 Supply section 3a Supply valve 3b CO2 supply equipment 4. Delayed carbon dioxide release mechanism 41 Discharge section 41a Overflow valve 42 Carbon dioxide delay section 42a Inner cylinder 42b outer cylinder 43 Drain pipe 43a Drain valve 5 Support 6. Blower 7 Differential pressure sensor 8 Air conditioning equipment 8a Air conditioning equipment intake 81 Air supply duct 91 Exhaust section 91a Exhaust valve 92 Exhaust fan 93 Intake section 93a Intake valve 93b Intake three-way valve H Hydraulic hardening body

Claims

1. The inside of the carbonation curing tank containing the hydraulic hardened body contains more CO than air. ２ a filling step of filling a gas containing high concentration carbon dioxide gas; a curing step of carbonating and curing the hydraulic hardened body with the carbon dioxide gas filled in the carbonation curing tank in the filling step; a discharging step of discharging gas containing at least carbon dioxide gas from the inside of the carbonation curing tank to the outside of the carbonation curing tank after the curing step; and The method for managing carbonation curing of a hydraulically hardened body comprises carrying out the filling step, the curing step, and the discharging step under different conditions, and carrying out control according to each step.

2. The filling step includes: a first filling step of filling the carbon dioxide-containing gas into the carbonation curing tank without stirring the gas in the carbonation curing tank; a second filling step, which is carried out after the first filling step, of agitating the gas in the carbonation curing tank and then filling the carbon dioxide-containing gas; The carbonation curing control method for a hydraulically hardened body according to claim 1, comprising:

3. In the curing step, a unidirectional airflow is generated in the carbonation curing tank to ２ 2. The method for managing carbonation curing of a hydraulically hardened body according to claim 1, wherein the gas containing the compound is continuously applied to the surface of the hydraulically hardened body.

4. In the curing step, when the pressure difference P (P = P1 - P2) between the internal pressure P1 of the carbonation curing tank and the external pressure P2 of the carbonation curing tank is P ≦ 0, 4. The method for managing carbonation curing of a hydraulic hardened body according to claim 1, wherein a mode 1 is performed in which a valve at a discharge part of the carbonation curing tank is closed and the carbon dioxide-containing gas is supplied into the carbonation curing tank.

5. In the curing step, when a pressure difference P (P = P1 - P2) between an internal pressure P1 of the carbonation curing tank and an external pressure P2 of the carbonation curing tank is P > 0, and an offset value P3 used as an allowable internal pressure of the carbonation curing tank is P < P3, 5. The method for managing carbonation curing of a hydraulic hardened body according to claim 4, wherein a mode 2 is performed in which a valve at a discharge part of the carbonation curing tank is closed and the carbon dioxide-containing gas is supplied into the carbonation curing tank at a supply rate slower than that of the mode 1.

6. In the curing step, when a pressure difference P (P = P1 - P2) between an internal pressure P1 of the carbonation curing tank and an external pressure P2 of the carbonation curing tank is P > 0, and an offset value P3 used as an allowable internal pressure of the carbonation curing tank is P > P3, 4. The method for managing carbonation curing of a hydraulically hardened body according to claim 1, wherein a valve of an exhaust part of the carbonation curing tank is opened to exhaust gas to the outside of the carbonation curing tank, and then the valve is closed, thereby performing mode 3.

7. 2. The method for managing carbonation curing of a hydraulic hardened body according to claim 1, wherein the method comprises a plurality of carbonation curing tanks, the carbonation curing tanks are connected to each other, and a gas containing at least carbon dioxide gas discharged to the outside of one of the carbonation curing tanks is supplied to the inside of another of the carbonation curing tanks.

8. a carbonation curing tank for accommodating the hydraulically hardened body; CO than air ２ A supply unit that supplies a highly concentrated carbon dioxide-containing gas into the carbonation curing tank; a discharge section that discharges gas containing at least carbon dioxide gas from the inside of the carbonation curing tank to the outside of the carbonation curing tank; Equipped with In the carbon dioxide-containing gas filling treatment, the carbon dioxide-containing gas is supplied and filled into the carbonation curing tank, In the curing treatment of the hydraulically hardened body, the hydraulically hardened body is carbonation cured with carbon dioxide gas filled inside the carbonation curing tank, In the discharge treatment of the gas containing at least carbon dioxide gas, after curing of the hydraulically hardened body, the gas containing at least carbon dioxide gas is discharged to the outside of the carbonation curing tank, A carbonation curing system for hydraulically hardened bodies, wherein the filling process, the curing process, and the discharging process are performed under different conditions and are controlled according to each process.

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