Carbon dioxide sequestration device and carbon dioxide sequestration method

Abstract

The present invention provides a carbon dioxide fixation apparatus and a carbon dioxide fixation method capable of both carbon dioxide fixation and classification of cementitious hardened materials. [Solution] The fixing device 80 includes a rotary drum 84 that brings granular cementitious hardened material into contact with carbon dioxide-containing gas and water vapor to promote the carbonation reaction of the cementitious hardened material, and a trommel 85 provided inside the rotary drum 84 that separates the cementitious hardened material supplied to the rotary drum 84 according to its size.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide immobilization apparatus and a carbon dioxide immobilization method. [Background Art]

[0002] Exhaust gas discharged from factories and the like contains carbon dioxide. Techniques for immobilizing this carbon dioxide to suppress carbon dioxide emissions into the atmosphere have been proposed. For example, Patent Document 1 describes a technique for immobilizing carbon dioxide in a powdery granular cementitious hardened body. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2022-146817 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] When such a powdery granular cementitious hardened body is used, it is desirable to be able to immobilize carbon dioxide more efficiently.

[0005] The present invention has been made in view of the above circumstances. Accordingly, an object of the present invention is to provide a carbon dioxide immobilization apparatus and a carbon dioxide immobilization method capable of more efficiently immobilizing carbon dioxide. [Means for Solving the Problem]

[0006] The above object of the present invention is achieved by the following.

[0007] (1) A carbon dioxide fixation apparatus comprising: a reaction section that brings a granular cementitious hardened body into contact with a carbon dioxide-containing gas and water vapor to promote a carbonation reaction of the cementitious hardened body; and a separation section provided inside the reaction section that separates the cementitious hardened body supplied to the reaction section according to its size.

[0008] (2) The carbon dioxide fixation apparatus according to (1) above, wherein the reaction section and the separation section extend in a predetermined direction, the reaction section has a first end and a second end in the predetermined direction, and the separation section has a third end closer to the first end and a fourth end closer to the second end in the predetermined direction.

[0009] (3) The carbon dioxide fixation apparatus according to (2) above, further comprising: a cementitious material supply unit configured to supply the cementitious material to the reaction unit; a first extraction unit configured to extract cementitious material of a first size or smaller separated by the separation unit; and a second extraction unit configured to extract cementitious material of a size larger than the first size separated by the separation unit.

[0010] (4) The carbon dioxide fixation apparatus according to (3) above, wherein the cementitious hardened body supply unit and the first and second extraction units are spaced apart in the predetermined direction.

[0011] (5) The carbon dioxide fixation apparatus according to (3) or (4) above, wherein the separation section includes a first sieve that sieves the cementitious hardened body of the first size or less to the outside of the separation section and to the inside of the reaction section.

[0012] (6) The carbon dioxide fixation apparatus according to (5) above, wherein the separation section further includes a second sieve for filtering out the cementitious hardened body, which is larger than the first size but no larger than the second size, to the outside of the separation section and to the inside of the reaction section.

[0013] (7) The carbon dioxide fixation apparatus according to (6) above, wherein the first sieve and the second sieve are arranged side by side in the predetermined direction.

[0014] (8) The carbon dioxide fixation apparatus according to (6) above, wherein the second sieve is arranged inside the first sieve.

[0015] (9) The carbon dioxide fixation apparatus according to any of (2) to (8) above, wherein the distance between the third end and the fourth end is less than or equal to the distance between the first end and the second end.

[0016] (10) The carbon dioxide fixation apparatus according to (9) above, wherein the reaction section has a rotating shaft connecting the first end and the second end, and the separation section has a rotating shaft connecting the third end and the fourth end, and the reaction section and the separation section are configured to be rotatable independently.

[0017] (11) The carbon dioxide fixation apparatus according to (9) or (10) above, wherein the first path of the cementitious hardened body from the first end to the second end outside the separation section and inside the reaction section, and the second path of the cementitious hardened body from the third end to the fourth end inside the separation section, are inclined at different angles with respect to the ground.

[0018] (12) The carbon dioxide fixation apparatus described in (11) above, wherein the second route has a smaller slope with respect to the ground than the first route.

[0019] (13) The carbon dioxide fixation apparatus according to any one of (1) to (12) above, further comprising a carbon dioxide-containing gas supply unit for supplying the carbon dioxide-containing gas to the reaction unit and a water vapor supply unit for supplying the water vapor to the reaction unit.

[0020] (14) The carbon dioxide fixation apparatus according to any one of (1) to (13) above, wherein the reaction section includes a rotary drum and the fractionation section includes a trommel.

[0021] A method for fixing carbon dioxide, comprising: bringing a powdery / granular cementitious hardened body into contact with a carbon dioxide-containing gas and water vapor in a reaction section (15) to allow the carbonation reaction of the cementitious hardened body to proceed; and sorting the cementitious hardened body according to its size in a sorting section provided inside the reaction section. [Advantageous Effects of Invention]

[0022] According to the carbon dioxide fixing device and carbon dioxide fixing method of the present invention, since the sorting section is provided inside the reaction section, the carbonation reaction of the cementitious hardened body and the sorting of the cementitious hardened body according to particle size can be performed simultaneously. Therefore, it becomes possible to fix carbon dioxide more efficiently. [Brief Description of Drawings]

[0023] [Figure 1] It is a diagram showing the overall configuration of a system including a carbon dioxide fixing device according to one embodiment. [Figure 2] It is a diagram showing an example of the configuration of the cement production facility shown in FIG. 1. [Figure 3] It is a side view schematically showing an example of the fixing device shown in FIG. 1. [Figure 4] It is a side view showing a more specific configuration of the fixing device shown in FIG. 3. [Figure 5A] It is a plan view showing an example of the configuration of the third end shown in FIG. 4. [Figure 5B] It is a plan view showing an example of the configuration of the fourth end shown in FIG. 4. [Figure 6] It is a side view showing an example of the fixing device according to Modification 1. [Figure 7] It is a side view showing another example of the fixing device shown in FIG. 6. [Figure 8] It is a side view showing an example of the fixing device according to Modification 2. [Mode for Carrying Out the Invention]

[0024] An embodiment of the carbon dioxide fixation apparatus and carbon dioxide fixation method of the present invention will be described below with reference to the attached drawings. In the drawings, the same reference numerals are used for the same components. Also, the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios.

[0025] <System Configuration> Figure 1 is a block diagram showing the overall configuration of a system to which a carbon dioxide fixation device 80 according to one embodiment of the present invention is applied. This system includes, for example, a cement manufacturing facility 10, a carbon dioxide storage unit 20, a flow rate control unit 30, a steam generation unit 40, a steam heating unit 50, a flow rate control unit 60, a crusher 70, and a fixation device 80. In this system, carbon dioxide is supplied to the fixation device 80 from the cement manufacturing facility 10, and steam is supplied from the steam generation unit 40. The cementitious hardened material used in the fixation device 80 is produced, for example, from waste concrete C. In the fixation device 80, carbon dioxide emitted from the cement manufacturing facility 10 is fixed to this cementitious hardened material.

[0026] Figure 2 shows a schematic configuration of cement manufacturing equipment 10. The cement manufacturing equipment 10 includes, for example, a raw material mill 11, a crushed raw material silo 12, a preheater 13, a dust collector 14, a carbon dioxide separation unit 15, a rotary kiln 16, a clinker cooler 17, and a finishing mill 18. For example, the preheater 13, the raw material mill 11, and the dust collector 14 are connected by an exhaust gas flow path (flue) R11.

[0027] The raw material mill 11 crushes cement raw materials M such as limestone.

[0028] The crushed raw material silo 12 stores the cement raw materials that have been crushed by the raw material mill 11.

[0029] The preheater 13 includes multiple cyclones and calcination furnaces and preheats the cement raw materials supplied from the crushed raw material silo 12. The exhaust gas from the preheater 13 is sent to the dust collector 14 via the exhaust gas flow path R11 and the raw material mill 11. The exhaust gas is used as a drying gas for the cement raw materials in the raw material mill 11.

[0030] The dust collector 14 collects dust from the exhaust gas sent from the preheater 13 through the exhaust gas passage R11. The dust collected by the dust collector 14 is sent to the crushed raw material silo 12 as a cement raw material.

[0031] The carbon dioxide separation equipment 15 separates carbon dioxide from the exhaust gas from which dust has been collected by the dust collector 14. The carbon dioxide separation equipment 15 separates carbon dioxide from the exhaust gas using known techniques such as cryogenic separation, chemical absorption, and membrane separation. The carbon dioxide-containing gas separated from the exhaust gas is sent to the carbon dioxide storage unit 20. Note that if the proportion of carbon dioxide in the exhaust gas is 5% or more, the exhaust gas from which carbon dioxide has not been separated may also be considered as carbon dioxide-containing gas.

[0032] The rotary kiln 16 fires the cement raw materials, which have been preheated by the preheater 13, to produce cement clinker.

[0033] The clinker cooler 17 cools the cement clinker produced by the rotary kiln 16.

[0034] The finishing mill 18 grinds the mixture of cement clinker and gypsum, which has been cooled by the clinker cooler 17, to complete the cement.

[0035] The carbon dioxide storage unit 20 stores carbon dioxide-containing gas sent from the carbon dioxide separation equipment 15. The carbon dioxide storage unit 20 includes, for example, a tank for storing the carbon dioxide-containing gas.

[0036] The carbon dioxide-containing gas stored in the carbon dioxide storage section 20 preferably contains 5% or more, more preferably 10% or more, even more preferably 15% or more, and particularly preferably 20% or more, of carbon dioxide as a volume fraction. When the proportion of carbon dioxide in the carbon dioxide-containing gas is 5% or more, the amount of carbon dioxide that is fixed increases, and the amount of carbon dioxide emitted into the atmosphere can be efficiently reduced.

[0037] The flow control unit 30 is installed in the flow path of carbon dioxide-containing gas between the carbon dioxide storage unit 20 and the immobilization device 80. This flow control unit 30 controls the flow rate of carbon dioxide-containing gas supplied from the carbon dioxide storage unit 20 to the immobilization device 80. The flow control unit 30 includes, for example, a flow meter and a control valve.

[0038] The steam generation unit 40 generates steam, for example, by heating water. The steam generation unit 40 includes, for example, a boiler.

[0039] The steam heating unit 50 is located in the steam flow path between the steam generation unit 40 and the flow control unit 60. This steam heating unit 50 heats the steam generated in the steam generation unit 40. This suppresses condensation between the time the steam generated in the steam generation unit 40 is supplied to the solidification device 80. The steam heating unit 50 includes, for example, a steam heater.

[0040] The flow control unit 60 is located in the steam flow path between the steam heating unit 50 and the immobilization device 80. This flow control unit 60 controls the flow rate of steam supplied from the steam heating unit 50 to the immobilization device 80. The flow control unit 60 includes, for example, a flow meter and a control valve.

[0041] The crusher 70 crushes the waste concrete C to produce a granular cementitious hardened material. The waste concrete C is transported to the system, for example, from a waste site by truck. Here, the cementitious hardened material refers to a composition containing cement and water that has hardened. The cementitious hardened material may be fully hardened or partially hardened. The partially hardened state is, for example, a state in which hardening is in progress. The cementitious hardened material may also be produced from a cement composition other than concrete, for example, from mortar or cement paste.

[0042] It is preferable to use waste materials for the cementitious hardened material that is crushed in the crusher 70. This allows for the reuse of waste materials. The granular cementitious hardened material can be produced, for example, from waste building materials, waste cement paste hardened material, or sludge generated in ready-mixed concrete.

[0043] The crusher 70 crushes waste concrete C, for example, into cementitious hardened material with a particle size of 100 mm or less. By reducing the particle size, the contact area between the cementitious hardened material and the carbon dioxide-containing gas increases, making it possible to increase the amount of carbon dioxide that is fixed. The crusher 70 crushes the waste concrete C into cementitious hardened material with a particle size of preferably 80 mm or less, more preferably 50 mm or less. Here, the particle size is the maximum dimension in the powder-like material, and for example, when the cross-section of the cementitious hardened material is elliptical, it refers to the dimension of its major axis. The powder-like cementitious hardened material crushed by the crusher 70 is supplied to the carbon dioxide fixation device 80. In carbon dioxide fixation, it is desirable to maintain a high humidity level in the reaction system. For this reason, the cementitious hardened material supplied to the fixation device 80 may contain moisture.

[0044] Figure 3 shows a schematic configuration of the carbon dioxide fixation device 80, and Figure 4 shows a more specific configuration of this fixation device 80. The fixation device 80 includes, for example, a hopper 81, a carbon dioxide supply unit 82, a steam supply unit 83, a rotary drum 84, a first sealing unit 84A, a second sealing unit 84B, a trommel 85, a first outlet unit 86, a second outlet unit 87, and an exhaust port 88. The rotary drum 84 and trommel 85 have, for example, a cylindrical shape. In the following description, the direction parallel to the ground H may be referred to as the X direction and the Y direction, and the vertical direction as the Z direction. The cylindrical rotary drum 84 and trommel 85 extend in the X direction. Here, the hopper 81 corresponds to a specific example of the cementitious hardened material supply unit of the present invention, the rotary drum 84 corresponds to a specific example of the reaction unit of the present invention, and the trommel 85 corresponds to a specific example of the fractionation unit of the present invention.

[0045] The granular cementitious material crushed in the crusher 70 is supplied to the inside of the rotary drum 84 via the hopper 81. The cementitious material is transported to the hopper 81 by a belt conveyor, for example, from a feeder. A dust collector may be provided in the supply path of the cementitious material from the crusher 70 to the hopper 81. It is desirable that the hopper 81 be configured to maintain airtightness inside the rotary drum 84, and for example, the hopper 81 includes a rotary valve and a double flap damper.

[0046] The carbon dioxide supply unit 82 supplies carbon dioxide-containing gas stored in the carbon dioxide storage unit 20 into the rotary drum 84. The carbon dioxide supply unit 82 includes, for example, a tubular member that connects the carbon dioxide storage unit 20 and the inside of the rotary drum 84. The carbon dioxide-containing gas supplied to the rotary drum 84 may be heated. This makes it possible to maintain a high temperature inside the rotary drum 84. The carbon dioxide-containing gas may contain water vapor.

[0047] The steam supply unit 83 supplies steam generated in the steam generation unit 40 into the rotary drum 84. The steam supply unit 83 includes, for example, a tubular member that connects the steam generation unit 40 to the inside of the rotary drum 84. The tubular members included in the carbon dioxide supply unit 82 and the steam supply unit 83 may be composed of double-pipe nozzles. It is desirable that the steam is supplied so that the humidity inside the rotary drum 84 is maintained at 30%RH to 90%RH.

[0048] A cavity is provided inside the cylindrical rotary drum 84. Cementaceous hardened material is supplied to this cavity from the hopper 81, carbon dioxide-containing gas from the carbon dioxide supply unit 82, and water vapor from the water vapor supply unit 83. Inside the rotary drum 84, the granular cementaceous hardened material is brought into contact with the carbon dioxide-containing gas and water vapor to promote the carbonation reaction of the cementaceous hardened material. As a result, the carbon dioxide in the carbon dioxide-containing gas is fixed in the cementaceous hardened material, reducing the amount of carbon dioxide emitted into the atmosphere.

[0049] The rotary drum 84, which extends in the X direction, has a first end 84EA and a second end 84EB in the X direction (Figure 4). The rotary drum 84 is positioned, for example, at an inclination with respect to the ground H, with the second end 84EB being closer to the ground H than the first end 84EA. For example, a hopper 81 is provided closer to the first end 84EA, and a carbon dioxide supply unit 82 and a water vapor supply unit 83 are provided closer to the second end 84EB. Inside the rotary drum 84, the cementitious hardened material supplied from the hopper 81 gradually moves toward the second end 84EB, and the carbon dioxide-containing gas and water vapor supplied from the carbon dioxide supply unit 82 and water vapor supply unit 83 flow from the second end 84EB toward the first end 84EA. By counter-flowing the cementitious hardened material with the carbon dioxide-containing gas and water vapor in this way, it is possible to improve the efficiency of the carbonation reaction.

[0050] The cementitious material moves along a first path P84 inside the rotary drum 84, from the first end 84EA to the second end 84EB. The first path P84 is, for example, a path for the cementitious material from the first end 84EA to the second end 84EB, outside the trommel 85 and inside the rotary drum 84. The first path P84 is inclined at a predetermined angle with respect to the ground H. For example, the inclination angle of the first path P84 with respect to the ground H can be adjusted by adjusting the inclination angle of the rotary drum 84 with respect to the ground H.

[0051] The first end 84EA of the rotary drum 84 is sealed by a first sealing portion 84A, and the second end 84EB of the rotary drum 84 is sealed by a second sealing portion 84B. It is preferable that the inside of the rotary drum 84 has high airtightness. This makes it possible to improve the efficiency of the carbonation reaction. The first sealing portion 84A and the second sealing portion 84B cover, for example, the first end 84EA and the second end 84EB.

[0052] The rotary drum 84 is configured to be rotatable and has a rotating shaft connecting the first end 84EA and the second end 84EB. By rotating the rotary drum 84 and bringing the cementitious hardened material into contact with carbon dioxide-containing gas and water vapor, the efficiency of the carbonation reaction can be improved. Between the rotary drum 84 and the ground H, for example, two roller supports 840 are provided, and as these rotate, the rotary drum 84 also rotates.

[0053] The rotary drum 84 is made of, for example, SUS. The rotary drum 84 may have, for example, a heater. This makes it possible to heat the inside of the rotary drum 84 and allow the carbonation reaction to proceed more efficiently. It is preferable that the temperature inside the rotary drum 84 be maintained at 80°C or higher. A lifter may be provided inside the rotary drum 84.

[0054] The trommel 85 is located inside the rotary drum 84. The trommel 85 is positioned, for example, away from the inner wall surface of the rotary drum 84.

[0055] The trommel 85 is positioned, for example, above the center of the rotary drum 84 in the Z direction. The trommel 85 extending in the X direction has a third end 85EA and a fourth end 85EB in the X direction. For example, the third end 85EA is located closer to the first end 84EA of the rotary drum 84, and the fourth end 85EB is located closer to the second end 84EB of the rotary drum 84.

[0056] The trommel 85 is positioned, for example, at an inclination with respect to the ground H, with the fourth end 85EB being closer to the ground H than the third end 85EA. The inclination angle of the trommel 85 and the inclination angle of the rotary drum 84 may be the same (Figure 3) or different (Figure 4). The size of the trommel 85 in the X direction is, for example, larger than the size of the rotary drum 84 in the X direction.

[0057] The trommel 85 has numerous holes and functions as a sieve. In this trommel 85, the cementitious material is separated according to its particle size as it moves from the third end 85EA to the fourth end 85EB. Specifically, cementitious material with a particle size larger than the holes in the trommel 85 remains inside the trommel 85, while cementitious material with a particle size smaller than or equal to the holes in the trommel 85 is sieved out to the outside of the trommel 85. By placing such a trommel 85 inside the rotary drum 84, the carbonation reaction of the cementitious material and the separation of the cementitious material according to its particle size occur simultaneously. The size of the holes in the trommel 85 is, for example, 10 mm to 40 mm.

[0058] The cementitious material moves along a second path P85 inside the trommel 85, from the third end 85EA to the fourth end 85EB. The second path P85 is, for example, a path for the cementitious material inside the trommel 85, from the third end 85EA to the fourth end 85EB. The second path P85 is inclined at a predetermined angle with respect to the ground H. For example, the inclination angle of the second path P85 with respect to the ground H can be adjusted by adjusting the inclination angle of the trommel 85 with respect to the ground H.

[0059] The inclination angles of the first path P84 and the second path P85 relative to the ground H may be the same or different. By making the inclination angle of the second path P85 relative to the ground H smaller than that of the first path P84 relative to the ground H, the carbonation time for cementitious material with relatively large particle sizes can be extended, thereby improving the carbonation rate in a single treatment. On the other hand, cementitious material with relatively small particle sizes can be carbonized in a short time, so increasing the inclination angle of the second path P85 shortens the treatment time. Because the required carbonation time can be set for each particle size, the carbonation reaction can be carried out efficiently even for cementitious material with a wide range of particle sizes.

[0060] The trommel 85 is configured to be rotatable and has a rotation axis 85R in the direction connecting the third end 85EA and the fourth end 85EB. By rotating the trommel 85 and moving the cementitious material from the third end 85EA side to the fourth end 85EB side, the cementitious material can be separated more efficiently. The rotation axis 85R is driven, for example, by a motor. A roller support 850 is provided between the trommel 85 and the inner wall of the rotary drum 84. The rotary drum 84 and the trommel 85 are configured to be rotatable independently, for example. The trommel 85 and the rotary drum 84 can each be controlled to any desired rotation, i.e., processing time. A lifter may be provided inside the trommel 85.

[0061] Figure 5A shows an example of the configuration of the YZ plane of the third end 85EA, and Figure 5B shows an example of the configuration of the YZ plane of the fourth end 85EB. The hopper 81 is connected, for example, to the third end 85EA of the trommel 85, and the hardened cementitious material supplied from the hopper 81 first enters the interior of the trommel 85. The fourth end 85EB is provided with, for example, a support section 85RS. For example, a rotating shaft 85R is supported by this support section 85RS. The hardened cementitious material overflows from the gap in the support section 85RS and is discharged from the second outlet section 87.

[0062] The first and second outlets 86 and 87 are provided, for example, on the rotary drum 84. These first and second outlets 86 and 87 are spaced apart from the hopper 81 in the X direction. The first and second outlets 86 and 87 are located closer to the second end 84EB than to the first end 84EA. The cementitious hardened material, in which carbon dioxide has been immobilized within the rotary drum 84, is recovered from the first and second outlets 86 and 87, respectively. It is desirable that the first and second outlets 86 and 87 be configured to maintain airtightness inside the rotary drum 84, and for example, the first and second outlets 86 and 87 include a rotary valve and a double flap damper, etc.

[0063] The first extraction section 86 is configured to allow extraction of cementitious hardened material with a particle size smaller than or equal to the holes in the trommel 85. The first extraction section 86 is located, for example, in the X direction, at a position corresponding to the fourth end 85EB of the trommel 85. The cementitious hardened material that has been sifted out to the outside of the trommel 85 is collected in this first extraction section 86.

[0064] The second removal section 87 is configured to allow the removal of cementitious material with a particle size larger than that of the trommel 85. The second removal section 87 is located, for example, in the X direction, closer to the second end 84EB than the first removal section 86. The cementitious material remaining inside the trommel 85 is collected in this second removal section 87.

[0065] Furthermore, when cementitious hardened material with fixed carbon dioxide is used as backfill material or roadbed material, particle size adjustment is unnecessary. For this reason, there may be only one extraction section (second extraction section 87) (Figure 4).

[0066] The exhaust port 88 is provided, for example, in the first sealing section 84A and discharges the gas inside the rotary drum 84. The gas discharged from the exhaust port 88 may contain fine particles such as cement that have been detached from the cementitious hardened body. The exhaust port 88 is positioned, for example, closer to the first end 84EA than to the second end 84EB. This allows the gas supplied into the rotary drum 84 from the carbon dioxide supply section 82 and the water vapor supply section 83 to be efficiently used in the carbonation reaction of the cementitious hardened body. The carbon dioxide-containing gas discharged from the exhaust port 88 may be supplied back into the rotary drum 84 from the carbon dioxide supply section 82. A dust collector such as a bag filter may be provided in the discharge path of the gas discharged from inside the rotary drum 84. For example, the fine particles such as cement collected by the dust collector may be reused as a cement mixing component.

[0067] <System Operation> In this system, carbon dioxide-containing gas, water vapor, and granular cementitious material are supplied to the rotary drum 84. The granular cementitious material is supplied to the trommel 85 inside the rotary drum 84 via the hopper 81.

[0068] The cementitious material supplied to the trommel 85 moves through the second path P85 to the fourth end 85EB. At this time, the carbon dioxide-containing gas and water vapor in the rotary drum 84 cause a carbonation reaction in the cementitious material, and carbon dioxide is fixed into the cementitious material. In parallel with the progress of this carbonation reaction, the cementitious material is sieved by the trommel 85 according to its particle size.

[0069] Hardened cementitious material with a particle size smaller than or equal to the holes in the trommel 85 is sifted out to the outside of the trommel 85 and removed from the first removal section 86. On the other hand, hardened cementitious material with a particle size larger than the holes in the trommel 85 remains inside the trommel 85 and is removed from the second removal section 87. The hardened cementitious material removed from the first removal section 86 and the hardened cementitious material removed from the second removal section 87 can be used for different purposes depending on their particle size. For example, hardened cementitious material with a relatively small particle size can be used as a cement mixer and concrete admixture, while hardened cementitious material with a relatively large particle size can be used as roadbed material, etc.

[0070] <Effects of the immobilization device> In the immobilization device 80 of this embodiment, a trommel 85 is provided inside the rotary drum 84, so that the carbonation reaction of the cementitious hardened material and the separation of the cementitious hardened material according to particle size occur simultaneously. Therefore, it becomes possible to immobilize carbon dioxide more efficiently. The effects of this will be explained below.

[0071] By using a rotary drum, carbon dioxide can be immobilized onto cementitious material in a semi-continuous manner. In this process, cementitious material with smaller particle sizes comes into contact with carbon dioxide more efficiently, and the carbonation reaction proceeds more easily. In other words, the progress of the carbonation reaction is uneven depending on the particle size of the cementitious material. Therefore, by using cementitious material with similar particle sizes to carry out the carbonation reaction, carbon dioxide can be immobilized more efficiently.

[0072] However, if the cementitious hardened material is separated according to particle size, and then carbon dioxide is immobilized for each particle size, then classification equipment and multiple rotary drums are required, which significantly increases the equipment area.

[0073] In contrast, in the immobilization device 80 of this embodiment, a trommel 85 is provided inside the rotary drum 84, so that the carbonation reaction and classification of the cementitious material proceed simultaneously within the rotary drum 84. As a result, cementitious material of similar particle size accumulates on both the inside and outside of the trommel 85, allowing the carbonation reaction to proceed efficiently. In other words, the required carbonation time for each particle size can be set, and cementitious material of various particle sizes can be efficiently carbonated. Therefore, it is possible to immobilize carbon dioxide in cementitious material more efficiently while suppressing an increase in the installation area.

[0074] Furthermore, since the immobilization device 80 has a first extraction section 86 and a second extraction section 87, the cementitious hardened material is recovered in a classified state. This makes it easier to use the cementitious hardened material for different applications according to its particle size.

[0075] Furthermore, in the stabilization device 80, the trommel 85 is positioned away from the inner wall of the rotary drum 84. This creates a space between the cementitious material supplied to the inside of the trommel 85 and the inner wall of the rotary drum 84, making it easier to adjust the temperature of the cementitious material.

[0076] In addition, in the immobilization device 80, the trommel 85 is positioned, for example, above the center of the rotary drum 84 in the Z direction. By supplying the cementitious material to the inside of the trommel 85, the space inside the rotary drum 84 can be utilized efficiently. In particular, as the cementitious material approaches the fourth end 85EB, it is shaken out to the outside of the trommel 85, so the overlap between the particles of the cementitious material is reduced, and the cementitious material and the carbon dioxide-containing gas can be brought into contact more efficiently. Therefore, it becomes possible to immobilize carbon dioxide into the cementitious material more efficiently.

[0077] The following describes modified versions of the immobilization device 80 described in the above embodiment. In order to avoid repetition, detailed explanations of configurations similar to those described in the above embodiment will be omitted below.

[0078] <Example 1> Figure 6 shows an example of the configuration of the immobilization device 80 according to Modification 1. In this immobilization device 80, the trommel 85 includes a first sieve 851, a second sieve 852, and a third sieve 853. Except for this point, the immobilization device 80 according to Modification 1 has the same configuration as the immobilization device 80 of the above embodiment and produces the same effects.

[0079] The cylindrical first sieve 851, second sieve 852, and third sieve 853 each have numerous holes, and the granular cementitious hardened material is sieved according to the size of these holes. For example, the hole size increases in the order of first sieve 851, second sieve 852, and third sieve 853. For example, along the X direction, the sieves are arranged in the order of first sieve 851, second sieve 852, and third sieve 853 from the third end 85EA side. Here, the hole size of the first sieve 851 corresponds to one specific example of the first size of the present invention, and the hole size of the second sieve 852 corresponds to one specific example of the second size of the present invention.

[0080] The trommel 85 is, for example, located inside the reaction vessel 89. The reaction vessel 89 has, for example, a rectangular parallelepiped shape extending in the X direction. The reaction vessel 89 has a first end 89EA and a second end 89EB in the X direction. For example, the cementitious material is supplied from the first end 89EA side. This reaction vessel 89 does not have a rotating shaft and does not rotate. For example, the trommel 85 located inside the reaction vessel 89 rotates along a rotating shaft 85R. The cementitious material sifted out of the trommel 85 is collected in a first outlet 86, a second outlet 87, a third outlet 861, or a fourth outlet 862 by a dispensing mechanism located inside the reaction vessel 89. The dispensing mechanism is, for example, a belt conveyor and a moving floor.

[0081] The first extraction section 86, the second extraction section 87, the third extraction section 861, and the fourth extraction section 862 are provided, for example, in the reaction vessel 89. For example, along the X direction, they are arranged in the order of the first extraction section 86, the third extraction section 861, the fourth extraction section 862, and the second extraction section 87 from the first end 89EA side.

[0082] The first extraction section 86 is configured to extract cementitious hardened material with a particle size smaller than or equal to the holes of the first sieve 851. The first extraction section 86 is positioned, for example, at a location corresponding to the end of the first sieve 851 in the X direction. This end of the first sieve 851 is the end on the fourth end 85EB side. The first extraction section 86 collects the cementitious hardened material that has been sifted out to the outside of the first sieve 851.

[0083] The third extraction section 861 is configured to extract cementitious hardened material having a particle size larger than that of the first sieve 851 and smaller than or equal to that of the second sieve 852. The third extraction section 861 is positioned, for example, at a location corresponding to the end of the second sieve 852 in the X direction. This end of the second sieve 852 is the end on the fourth end 85EB side. The third extraction section 861 collects cementitious hardened material that remains inside the first sieve 851 and is sifted out to the outside of the second sieve 852.

[0084] The fourth extraction section 862 is configured to extract cementitious hardened material having a particle size larger than that of the second sieve 852 and smaller than or equal to that of the third sieve 853. The fourth extraction section 862 is positioned, for example, at a location corresponding to the end of the third sieve 853 in the X direction. This end of the third sieve 853 is the end on the fourth end 85EB side. The fourth extraction section 862 collects cementitious hardened material that remains inside the second sieve 852 and is sifted out to the outside of the third sieve 853.

[0085] The second extraction section 87 is configured to allow extraction of cementitious hardened material with a particle size larger than that of the holes in the third sieve 853. The second extraction section 87 is positioned, for example, in the X direction, closer to the second end 84EB than to the third sieve 853. The cementitious hardened material remaining inside the third sieve 853 is collected in this second extraction section 87.

[0086] In this way, by arranging the first sieve 851, the second sieve 852, and the third sieve 853 in that order from the third end 85EA side, the cementitious material with relatively small particle sizes is gradually sifted out to the outside of the trommel 85, while the cementitious material with relatively large particle sizes remains inside the trommel 85. In other words, the larger the particle size, the longer the carbonation time inside the trommel 85. This reduces the unevenness in the amount of carbon dioxide fixed due to variations in particle size.

[0087] The immobilization device 80 may have a rotary drum 84 instead of a reaction vessel 89. In this immobilization device 80, for example, a first outlet section 86, a second outlet section 87, a third outlet section 861, and a fourth outlet section 862 may be formed by making holes in a part of the rotary drum 84, or a first outlet section 86, a second outlet section 87, a third outlet section 861, and a fourth outlet section 862 may be formed by making a mesh-like structure in a part of the rotary drum 84. The first outlet section 86, the second outlet section 87, the third outlet section 861, and the fourth outlet section 862 are provided with, for example, covers. This maintains airtightness inside the rotary drum 84.

[0088] Figure 7 shows another example of the arrangement of the first sieve 851, the second sieve 852, and the third sieve 853. The second sieve 852 may be positioned inside the first sieve 851, and the third sieve 853 may be positioned inside the second sieve 852. By arranging the first sieve 851, the second sieve 852, and the third sieve 853 in overlapping positions in the X direction, the space inside the rotary drum 84 can be utilized more widely, allowing for more efficient contact between the cementitious hardened material and carbon dioxide. Note that the first sealing section 84A and the second sealing section 84B (see Figure 3, etc.) are not shown in Figure 7.

[0089] The sizes of the first sieve 851, the second sieve 852, and the third sieve 853 in the X direction are, for example, different from each other. The sizes in the X direction increase in the order of the first sieve 851, the second sieve 852, and the third sieve 853. As a result, the carbonation time inside the trommel 85 increases as the particle size increases. This reduces the unevenness in the amount of carbon dioxide fixed due to variations in particle size.

[0090] In the immobilization device 80 according to Modification 1, a trommel 85 is provided inside the rotary drum 84, similar to the immobilization device 80 according to the above embodiment. Therefore, the carbonation reaction of the cementitious hardened material and the separation of the cementitious hardened material according to particle size occur simultaneously. Consequently, it becomes possible to classify the cementitious hardened material along with the immobilization of carbon dioxide.

[0091] Furthermore, since the trommel 85 contains multiple sieves with different pore sizes (first sieve 851, second sieve 852, and third sieve 853), it can reduce the unevenness in carbon dioxide fixation caused by variations in particle size, thereby allowing the carbonation reaction to proceed more efficiently. It can also classify cementitious hardened materials more precisely.

[0092] <Modification 2> Figure 8 shows an example of the configuration of the immobilization device 80 according to Modification 2. In this immobilization device 80, the third end 85EA of the trommel 85 is located away from the hopper 81. The hopper 81 is connected, for example, to the first end 84EA of the rotary drum 84. Except for this point, the immobilization device 80 according to Modification 2 has the same configuration as the immobilization device 80 of the above embodiment and produces the same effects. Note that the first sealing part 84A and the second sealing part 84B (see Figure 3, etc.) are not shown in Figure 8.

[0093] The third end 85EA of the trommel 85 is located at position 84EC between the first end 84EA and the second end 84EB of the rotary drum 84. The size of the YZ plane of the third end 85EA of the trommel 85 is approximately the same as the size of the YZ plane of the rotary drum 84 at position 84EC. This facilitates the movement of the cementitious material supplied from the hopper 81 into the rotary drum 84 into the trommel 85 at position 84EC.

[0094] In the hardened cementitious material supplied from the hopper 81, a carbonation reaction proceeds, and this hardened cementitious material moves from the first end 84EA of the rotary drum 84 toward position 84EC. At position 84EC, the hardened cementitious material enters the trommel 85, and from position 84EC, the carbonation reaction of the hardened cementitious material and the separation of the hardened cementitious material according to particle size occur simultaneously.

[0095] In this type of solidification device 80, the cementitious material supplied from the hopper 81 first comes into contact with the inner wall of the rotary drum 84, thus accelerating the temperature rise of the cementitious material. Furthermore, as the heated cementitious material moves into the trommel 85 at position 84EC, it is possible to suppress excessive temperature increases. In addition, the movement of the cementitious material into the trommel 85 at position 84EC also helps to suppress the decrease in moisture content.

[0096] In the fixation device 80 according to the modified example 2, a trommel 85 is provided inside the rotary drum 84, similar to the fixation device 80 according to the above embodiment. Therefore, the carbonation reaction of the cementitious hardened material and the separation of the cementitious hardened material according to particle size are carried out simultaneously. Thus, it is possible to classify the cementitious hardened material along with the fixation of carbon dioxide. For example, the rotary drum 84 and the trommel 85 may be integrated by welding or the like. This simplifies the configuration of the drive device for driving the rotary drum 84 and the trommel 85.

[0097] Furthermore, since the third end 85EA of the trommel 85 is positioned at 84EC, it becomes easier to adjust the temperature rise and moisture content of the cementitious hardened body. Therefore, carbon dioxide can be fixed more efficiently.

[0098] The configuration of the immobilization device 80 and system described above is intended to illustrate the main configuration in order to explain the features of the above-described embodiment, and is not limited to the above configuration, and can be modified in various ways within the scope of the claims. Furthermore, it does not preclude configurations that are generally found in immobilization devices 80 and systems.

[0099] For example, the above embodiment describes an example in which carbon dioxide-containing gas emitted from cement manufacturing equipment 10 is supplied to the immobilization device 80, but it is not limited to this. Carbon dioxide-containing gas emitted from other equipment and factories may also be supplied to the immobilization device 80.

[0100] Furthermore, in the above embodiments, a rotary drum 84 was described as one specific example of the reaction section of the present invention, and a trommel 85 was described as one specific example of the fractionation section of the present invention, but the invention is not limited thereto. The reaction section and fractionation section may have shapes other than cylindrical, and may not have a rotating shaft. [Explanation of symbols]

[0101] 10. Cement manufacturing equipment, 11. Raw material mill, 12 silos for crushed raw materials, 13. Preheater, 14,34 Dust collector, 20 Carbon dioxide storage section, 30,60 Flow control unit, 40. Steam generation section, 50 Steam heating section, 70 pulverizers, 80 immobilization device, 81 Hopper, 82 Carbon Dioxide Supply Department, 83 Steam supply unit, 84 Rotary Drum, 85 Trommel, 86 1st extraction section, 87 2nd extraction section, 88 Exhaust vent.

Claims

1. A reaction unit that brings a granular cementitious hardened material into contact with a carbon dioxide-containing gas and water vapor to promote the carbonation reaction of the cementitious hardened material, A separation section is provided inside the reaction section and separates the cementitious hardened material supplied to the reaction section according to its size. A carbon dioxide fixation device equipped with [a specific feature].

2. The reaction section and the separation section extend in a predetermined direction. The reaction section has a first end and a second end in the predetermined direction, The carbon dioxide fixation apparatus according to claim 1, wherein the separation unit has a third end closer to the first end and a fourth end closer to the second end in the predetermined direction.

3. A cementitious material supply unit configured to supply the cementitious material to the reaction unit, A first removal unit is configured to allow removal of the cementitious hardened material of a first size or smaller that has been separated by the separation unit, A second extraction unit is configured to allow extraction of the cementitious hardened material, which has been separated by the aforementioned extraction unit and is larger than the first size, and The carbon dioxide fixation apparatus according to claim 2, further comprising the above.

4. The carbon dioxide fixation apparatus according to claim 3, wherein the cementitious hardened body supply unit, the first extraction unit, and the second extraction unit are arranged at a distance from each other in the predetermined direction.

5. The carbon dioxide fixation apparatus according to claim 3, wherein the separation section includes a first sieve that sieves the cementitious hardened body of size 1 or less to the outside of the separation section and to the inside of the reaction section.

6. The carbon dioxide fixation apparatus according to claim 5, wherein the separation section further includes a second sieve for sifting the cementitious hardened body, which is larger than the first size but no larger than the second size, to the outside of the separation section and the inside of the reaction section.

7. The carbon dioxide fixation apparatus according to claim 6, wherein the first sieve and the second sieve are arranged side by side in the predetermined direction.

8. The carbon dioxide fixation apparatus according to claim 6, wherein the second sieve is arranged inside the first sieve.

9. The carbon dioxide fixation apparatus according to claim 2, wherein the distance between the third end and the fourth end is less than or equal to the distance between the first end and the second end.

10. The reaction section has a rotating shaft connecting the first end and the second end, The sorting section has a rotating shaft connecting the third end and the fourth end, The carbon dioxide fixation apparatus according to claim 2, wherein the reaction unit and the separation unit are configured to be independently rotatable.

11. The carbon dioxide fixation apparatus according to claim 2, wherein the first path of the cementitious hardened body, which is located outside the separation section and inside the reaction section, and the second path of the cementitious hardened body, which is located inside the separation section, and which is located inside the separation section, are inclined at different angles with respect to the ground.

12. The carbon dioxide fixation apparatus according to claim 11, wherein the second path has a smaller inclination with respect to the ground than the first path.

13. A carbon dioxide-containing gas supply unit that supplies the carbon dioxide-containing gas to the reaction unit, A steam supply unit that supplies the steam to the reaction unit and The carbon dioxide fixation apparatus according to claim 1, further comprising the above.

14. The reaction section includes a rotary drum. The carbon dioxide fixation apparatus according to claim 1, wherein the separation unit includes a trommel.

15. In the reaction chamber, the granular cementitious hardened material is brought into contact with carbon dioxide-containing gas and water vapor to promote the carbonation reaction of the cementitious hardened material. In the separation section provided inside the reaction section, the cementitious hardened material is separated according to its size. A method for fixing carbon dioxide, including [a specific substance].

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