JP2021169398A - Carbon dioxide storage method and cement-based hardened body - Google Patents

Abstract

To provide a storage method of carbon dioxide or the like, in which the execution place is not limited to the vicinity of a site where a carbon dioxide-containing gas is generated, a large facility or the like is not required, and it can be easily carried out.SOLUTION: A hollow body containing a carbon dioxide-containing gas is produced, and the hollow body is stored in a cement-based hardened body. The hollow body is mixed with one of the cement-based materials and kneaded together with other cement-based materials to form a cement kneaded material, and the cement kneaded material can be cured. The hollow body can be kneaded with a cement-based material to form a cement kneaded material, and the cement kneaded material may be cured. The cement-based material is kneaded to form a cement kneaded material, and the hollow body may be mixed with the cement kneaded material and then cured. The hollow body containing the carbon dioxide-containing gas is produced in a facility discharging carbon dioxide-containing gas, and the hollow body can be stored in the cement-based hardened body in the facility other than the facility discharging the carbon dioxide-containing gas.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for storing carbon dioxide using a cement-based cured product and the like.

Today, reducing carbon dioxide emissions is an urgent issue as a measure against global warming. In addition to reducing carbon dioxide emissions through energy conservation and fuel conversion, carbon dioxide contained in gas emitted from the atmosphere and combustion equipment, etc. Development of technology for fixing and storing carbon is underway. As one of them, a technique of fixing carbon dioxide by bringing carbon dioxide-containing exhaust gas or the like into contact with concrete to cause a carbonation reaction is known.

Specifically, as shown in FIG. 2, carbon dioxide-containing gas emitted from a power plant, a steel mill, a cement factory, etc., which is a carbon dioxide emission source 21, is installed in the factory by a pipeline, a gas cylinder, and a dedicated vehicle 22. It will be transported to the concrete manufacturing equipment 23, the external concrete product factory 24, and the ready-mixed concrete factory 25. Then, carbon dioxide-containing gas is brought into contact with the hardened concrete produced in the respective facilities and factories 23, 24, and 25 in the curing layers 26, 27, and 28 to fix the carbon dioxide, and the hardened concrete carbonate 29. After setting 30 and 31, carbon dioxide is stored at the construction site 32 and the like.

As the carbon dioxide fixation technique, Patent Document 1 states that a concrete composition containing water, cement, an admixture, and an aggregate is hardened on the surface of a concrete structure, and carbon dioxide in the atmosphere is fixed on the surface layer. A carbon dioxide-immobilized concrete structure comprising a carbon dioxide-immobilized molded body is disclosed.

Further, Patent Document 2 describes a carbonated curing facility using a thermal power plant as a carbonic acid gas supply source used for carbonating and curing a living body, a carbonated concrete manufacturing method, and a carbonic acid gas immobilization method. There is.

In Patent Document 3, when a carbon dioxide-containing gas is brought into contact with a cementum-hardened body, a carbon dioxide-containing gas having a specific water content and temperature is used as the carbon dioxide-containing gas, whereby the carbon dioxide-containing gas is brought into the cementum-hardened body. A method for efficiently immobilizing the carbon dioxide in it is described.

Japanese Unexamined Patent Publication No. 2008-75391 Japanese Unexamined Patent Publication No. 2012-126623 Japanese Unexamined Patent Publication No. 2020-15569

However, in the invention described in the above patent document, since it is necessary to bring the carbon dioxide-containing gas directly into contact with concrete or the like, the place of implementation is limited to the vicinity of the place where the carbon dioxide-containing gas is generated. In addition, when the object for immobilizing carbon dioxide becomes large, the curing layer and the gas supply facility become large, which makes it difficult to implement.

The present invention has been made in view of the above-mentioned problems in the prior art, and the place of implementation is not limited to the vicinity of the place where carbon dioxide-containing gas is generated, large-scale equipment or the like is not required, and the present invention can be easily implemented. It is an object of the present invention to provide a carbon dioxide storage method and the like that can be used.

In order to achieve the above object, the method for storing carbon dioxide of the present invention is characterized in that a hollow body containing a carbon dioxide-containing gas is produced and the hollow body is stored in a cement-based hardened body. The carbon dioxide-containing gas also includes the carbon dioxide gas itself.

According to the present invention, by forming a hollow body containing carbon dioxide-containing gas, it is not necessary to directly contact the carbon dioxide-containing gas with concrete or the like to cause a carbonation reaction as in the conventional method, and a normal kneading method is used. Since carbon dioxide can be stored in the cement-based hardened body by using the above, large-scale equipment or the like is not required, and it can be easily carried out.

In the carbon dioxide storage method, the hollow body can be mixed with one of the cement-based materials and kneaded together with the other cement-based materials to form a cement kneaded product, and the cement kneaded product can be cured. Further, the hollow body may be kneaded together with a cement-based material to form a cement kneaded product, and the cement kneaded product may be hardened. Further, the cement-based material may be kneaded to obtain a cement kneaded product, and the hollow body may be mixed with the cement kneaded product and then cured.

Further, a hollow body containing the carbon dioxide-containing gas is manufactured in a facility that discharges the carbon dioxide-containing gas, and the hollow body is stored in a cement-based hardened body in a facility other than the facility that discharges the carbon dioxide-containing gas. Therefore, the place of implementation is not limited to the vicinity of the place where carbon dioxide-containing gas is generated.

By forming the hollow body into hollow particles of 1 μm or more and 1000 μm or less, carbon dioxide can be stored and the fire resistance, heat insulating property, freeze-thaw resistance and the like of the cement-based cured body can be improved. The hollow body can also be used as a fine aggregate or a coarse aggregate.

Further, the present invention is characterized in that it is a cement-based hardened body and includes a hollow body containing a carbon dioxide-containing gas. According to the present invention, carbon dioxide can be stored in the cement-based cured product.

By forming the hollow body into hollow particles having a particle size of 1 μm or more and 1000 μm or less, it is possible to improve the fire resistance, heat insulating property, freeze-thaw resistance, etc. of the cement-based cured product in addition to the storage of carbon dioxide. The hollow body can also be used for mortar or concrete as a fine aggregate or a coarse aggregate.

As described above, according to the present invention, the implementation location is not limited to the vicinity of the carbon dioxide-containing gas generation location, a large-scale facility or the like is not required, and a carbon dioxide storage method and the like that can be easily implemented. Can be provided.

It is a flowchart which shows one Embodiment of the carbon dioxide storage method which concerns on this invention. It is a flowchart which shows an example of the conventional carbon dioxide storage method.

Next, a mode for carrying out the present invention will be described in detail.

FIG. 1 shows an embodiment of a carbon dioxide storage method according to the present invention, in which carbon dioxide-containing gas emitted from a power plant, a steel mill, a cement factory, etc., which is a carbon dioxide emission source 1, contains carbon dioxide. It is included in the hollow particles at the hollow particle manufacturing plant 2. Next, the manufactured hollow particles are transported to the ready-mixed concrete factory 3, the ready-mixed concrete plant 4 at the construction site, and the concrete product factory 5. Then, the hollow particles are kneaded together with concrete at the ready-mixed concrete factory 3 or the ready-mixed concrete plant 4 at the construction site to form a hollow particle-containing kneaded product 6, which is cured at the construction site 8 to store carbon dioxide. On the other hand, in the concrete product factory 5, hollow particles are kneaded together with concrete and hardened, transported to a construction site 8 as a hollow particle-containing hardened body 7, and installed to store carbon dioxide.

In the present invention, hollow particles can be stored in a cement-based hardened body containing cement paste and mortar in addition to the concrete.

The hollow body used in the present invention preferably has a cavity contained in the particles, contains carbon dioxide-containing gas inside, and can maintain its shape in a cement-based hardened body for a long period of time.

The material of the organic hollow body is not particularly limited as long as it is generally used as an admixture for cement or concrete, but acrylonitrile, acrylic acid ester, methacrylic acid ester, phenol, etc. There are polymethylmethacrylate, methacrylonitrile, polystyrene, vinylidene chloride, vinyl acetate, polyphenol and the like, and they may be copolymers or crosslinked products. As the material of the inorganic hollow body, those containing silicon dioxide, aluminum oxide, calcium carbonate or the like as main components are preferable.

The method of including carbon dioxide in the hollow body is not particularly limited, but the following method can be used.

As described in JP-A-2017-165890, after coating carbon dioxide bubbles with a mixture containing a polymerizable monomer containing a polyfunctional (meth) acrylate compound and a polymerization initiator, heating and / or activity The polymerizable monomer is reacted by irradiation with energy rays.

As described in JP-A-2019-94226, bubbles containing a silicon compound having a hydrolyzable functional group are generated in a reaction solution containing water, and water of the silicon compound is added at the interface between the bubbles and the reaction solution. A solid film having a siloxane bond is formed by decomposition and dehydration condensation.

As described in Japanese Patent Application Laid-Open No. 2013-216545, after adjusting the pH of the calcium (Ca) salt aqueous solution with an alkaline solution and an acid solution, carbonic acid gas is blown into the hollow so as to obtain a predetermined pH change curve. Synthesize the body.

When the hollow body used in the present invention is a hollow particle having a small particle size, the range of the particle size and the film thickness is defined in JP-A-2005-263595, JP-A-2017-36186, and JP-A-2017-104639. It may be the same as the hollow particles generally used for the cement-based cured product as described in the above, and the particle size is preferably about 1 to 1000 μm, preferably 10 to 500 μm. More preferably, 20 to 100 μm is further preferable. If the particle size is small, a sufficient carbon dioxide fixing effect may not be obtained, and if the particle size is large, the properties of the cement kneaded product may be affected.

The film thickness of the hollow particles is preferably about 0.05 to 50 μm, more preferably 0.5 to 25 μm, and even more preferably 1 to 5 μm. When the film thickness is thin, the hollow particles are broken and the contained carbon dioxide is not stored, and when the film thickness is thick, the amount of carbon dioxide stored per particle is reduced, which is not preferable.

The particle size and film thickness of the hollow particles can be measured by using, for example, a laser diffraction type particle size distribution meter, and the film thickness can be measured, for example, by polishing a sample in which hollow particles are impregnated with a resin and fixed. The particle cross section can be exposed and measured with a scanning electron microscope or the like.

The amount of the hollow particles used is preferably 3 to 30% by volume, more preferably 5 to 15% by volume, in proportion to the cement kneaded product. If it is less than 3% by volume, a sufficient amount of carbon dioxide cannot be stored, and if it exceeds 30% by volume, the physical characteristics of the cement-based cured product deteriorate, or the ratio of hollow particles exposed on the surface of the cured product is high. In some cases, the number of hollow particles increases and the hollow particles are damaged due to external factors, making it impossible to store carbon dioxide.

By using the hollow particles containing carbon dioxide-containing gas as the hollow particles, it is possible to store carbon dioxide and improve the fire resistance, heat insulating property, freeze-thaw resistance and the like of the cement-based cured product.

Further, the hollow body according to the present invention may have a particle size of several millimeters or more instead of the hollow particles having a small particle size, and may be used for mortar or concrete as a fine aggregate or a coarse aggregate.

In storing the hollow body in the cement-based hardened body in the present invention, the hollow body is mixed with one of the cement-based materials and kneaded together with other cement-based materials to obtain a cement kneaded product, and the cement-based kneaded product is cured. Further, the hollow body may be kneaded together with a cement-based material to form a cement kneaded product, and the cement kneaded product may be hardened. Further, the cement-based material may be kneaded to obtain a cement kneaded product, and the hollow body may be mixed with the cement kneaded product and then cured.

As an example, when the hollow body in the present invention is added to concrete, the hollow body may be premixed with cement or the like in advance and then kneaded, or may be mixed at the same time as other materials at the time of kneading. Alternatively, a method may be used in which a hollow body is added to the mixed cement-based kneaded material afterwards, and the mixture is kneaded and mixed again. For example, a return concrete or a residual concrete that has not been used after shipping the ready-mixed concrete can be utilized.

As a device used for kneading, it is possible to use a normal hovert mixer, a concrete mixer such as a biaxial mixer, a tilting mixer, or an omni mixer, or a truck agitator capable of transporting and mixing concrete.

Further, by enclosing carbon dioxide in the hollow body, it can be treated as a solid, so that it can be easily transported. Therefore, it can be used as a hollow body in a cement factory or a power plant that emits a large amount of carbon dioxide, and transferred to a ready-mixed concrete factory, a product factory, a ready-mixed concrete plant at a construction site, or the like. Furthermore, in ready-mixed concrete factories and ready-mixed concrete plants, the smelted product can be shipped to the site, so the shape of the cured product can be freely set by using a mold that suits the purpose, and cement. It is possible to increase the amount of carbon dioxide stored by the hardened concrete, and it is possible to promote efficient storage of carbon dioxide because the pipeline and dedicated vehicle used for transporting carbon dioxide are no longer required.

1 Carbon dioxide emission source 2 Carbon dioxide-containing hollow particle factory 3 Raw particle factory 4 Raw concrete plant 5 Product factory 6 Hollow particle-containing kneaded product 7 Hollow particle-containing cured product 8 Construction site

Claims (10)

Manufacture a hollow body containing carbon dioxide-containing gas,
A method for storing carbon dioxide, which comprises storing the hollow body in a cement-based hardened body. The method for storing carbon dioxide according to claim 1, wherein the hollow body is mixed with one of the cement-based materials and kneaded together with another cement-based material to form a cement kneaded product, and the cement-based material is hardened. .. The method for storing carbon dioxide according to claim 1, wherein the hollow body is kneaded together with a cement-based material to form a cement kneaded product, and the cement kneaded product is hardened. The method for storing carbon dioxide according to claim 1, wherein the cement-based material is kneaded to obtain a cement kneaded product, and the hollow body is mixed with the cement kneaded product and then cured. It is characterized in that a hollow body containing the carbon dioxide-containing gas is manufactured in a facility that discharges the carbon dioxide-containing gas, and the hollow body is stored in a cement-based hardened body in a facility other than the facility that discharges the carbon dioxide-containing gas. The method for storing carbon dioxide according to any one of claims 1 to 4. The method for storing carbon dioxide according to any one of claims 1 to 5, wherein the hollow body is hollow particles of 1 μm or more and 1000 μm or less. The method for storing carbon dioxide according to any one of claims 1 to 5, wherein the hollow body is used as a fine aggregate or a coarse aggregate. A cement-based hardened body characterized by containing a hollow body containing a carbon dioxide-containing gas. The cement-based cured product according to claim 8, wherein the hollow body is hollow particles having a particle size of 1 μm or more and 1000 μm or less. The cement-based hardened body according to claim 8, wherein the hollow body is a fine aggregate or a coarse aggregate.

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