Solid material for recovering carbon dioxide, and method for producing same

Abstract

The present invention is a solid material for recovering carbon dioxide, which comprises 50% by weight to 99% by weight of sodium ferrite and 1% by weight to 50% by weight of an organic or inorganic binder, in which the average particle diameter is 1 mm to 10 mm, the specific surface area is 1 m2 / g to 50 m2 / g, and the axis ratio of the average major axis length of primary particles of the sodium ferrite to the average minor axis length of the primary particles is 1 to 2.

Description

Solid carbon dioxide capture material and its manufacturing method

[0001] The present invention relates to a solid recovery material that fixes carbon dioxide and a method for producing the same, and more particularly to a solid recovery material containing sodium ferrite and a method for producing the same.

[0002] Research into the capture, storage, and utilization of carbon dioxide has been ongoing for some time now in order to reduce the amount of carbon dioxide released into the atmosphere. Large-scale sources of carbon dioxide include thermal power plants, boilers in manufacturing plants, and kilns in cement plants, which use coal, heavy oil, natural gas, etc. as fuel. Other sources include blast furnaces in steel plants, which reduce iron oxide with coke, and transportation vehicles such as automobiles, ships, and airplanes, which use gasoline, heavy oil, or light oil as fuel.

[0003] Currently, large-scale facilities such as thermal power plants use aqueous amine solutions to capture and fix carbon dioxide. This method uses a liquid capture material, which has the advantage that the material can be transported using a pump.

[0004] However, since the above-mentioned method uses a liquid containing hazardous materials, it is difficult to operate in small and medium-sized facilities such as waste incineration plants, and as a result, the current situation is that carbon dioxide fixation and capture is hardly performed. For this reason, hopes are being placed on a solid carbon dioxide capture material made of a solid, particularly a non-hazardous inorganic material. As a conventional solid carbon dioxide capture material, Patent Documents 1 and 2 disclose a carbon dioxide capture material containing sodium ferrite. In particular, α-sodium ferrite with a layered rock salt structure (trigonal system) reacts topochemically with carbon dioxide and sodium. That is, during the reaction with carbon dioxide, α-sodium ferrite reacts with Na １－ｘ FeO ２ and sodium carbonate. Therefore, it has been reported that the reaction rate is high and the repeated absorption and release of carbon dioxide due to this reaction is excellent. On the other hand, since sodium reacts with carbon dioxide in orthorhombic β-sodium ferrite, it has been reported that the crystalline phase of β-sodium ferrite absorbs more carbon dioxide than the crystalline phase of α-sodium ferrite.

[0005] Generally, the reaction of sodium ferrite with carbon dioxide is as follows when the gas does not contain water vapor: ２ +1 / 2CO ２ →1 / 2Na ２ CO ３ +1 / 2Fe ２ O ３ , when water vapor is included, NaFeO ２ +CO ２ +1 / 2H ２ O → NaHCO ３ +1 / 2Fe ２ O ３ Therefore, sodium ferrite has the theoretical ability to adsorb and desorb a maximum of 18 to 28% by weight of carbon dioxide.

[0006] JP 2016-3156 A JP 2017-109198 A

[0007] As described above, the solid carbon dioxide capture materials described in Patent Documents 1 and 2 contain sodium ferrite, and are considered to be solid capture materials with relatively good carbon dioxide absorption performance in low-temperature regions. However, there is still a demand for carbon dioxide capture materials with higher carbon dioxide fixation and capture performance, and in addition to improving the properties of the sodium ferrite itself, it is necessary to further improve the properties of the material in the form in which it is installed in a carbon dioxide capture device. Specifically, sodium ferrite powder is difficult to handle in its powder form, and particularly when sodium ferrite is used by filling an adsorption tower with it, the fine powder tends to become densely packed and cause pressure loss, so it is granulated into a predetermined shape before use. For this reason, the composition and physical properties of the carbon dioxide capture material in the granulated state of sodium ferrite are also important.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a solid carbon dioxide recovery material that can fix carbon dioxide in a low temperature range of from room temperature to 200°C, can recover carbon dioxide by heating at 50°C to 200°C, and has excellent fixation and recovery performance, and a method for producing the same.

[0009] In order to achieve the above object, in the present invention, sodium ferrite is molded using an organic binder or an inorganic binder under predetermined conditions, thereby making it possible to adsorb carbon dioxide in a temperature range from room temperature to 200°C, and to recover the adsorbed carbon dioxide with high efficiency by heating at 50°C to 200°C.

[0010] Specifically, the solid carbon dioxide recovery material according to the present invention is a solid carbon dioxide recovery material containing 50% by weight to 99% by weight of sodium ferrite and 1% by weight to 50% by weight of an organic binder or an inorganic binder, and has an average particle size of 1 mm to 10 mm and a specific surface area of ​​1 m ２ / g to 50m ２ / g, and the aspect ratio of the average major axis diameter to the average minor axis diameter of the primary particles of the sodium ferrite is 1 to 2.

[0011] According to the solid carbon dioxide recovery material of the present invention, the organic or inorganic binder promotes the aggregation of sodium ferrite particles, thereby forming a compact containing a high concentration of sodium ferrite. Therefore, the solid carbon dioxide recovery material of the present invention, which contains sodium ferrite and an organic or inorganic binder, has the excellent property of adsorbing carbon dioxide in a gas, trapping it within the solid, and releasing the carbon dioxide when heated. Furthermore, if the average particle size is 1 mm to 10 mm, when the material is filled into an adsorption tower or the like, a flow path for exhaust gases and the like can be secured without reducing the pressure loss caused by the concentration of fine powder. As a result, carbon dioxide can be efficiently fixed. Furthermore, if the specific surface area is 1 m, ２ If the specific surface area is less than 50 m / g, the carbon dioxide contained in the gas is hardly contacted, the carbon dioxide fixation and recovery performance is reduced, and ２ / g, industrial production becomes difficult. Furthermore, since the axial ratio of the average major axis diameter to the average minor axis diameter of the primary particles of sodium ferrite is small, at 1 to 2, and the primary particles have a nearly spherical shape, the dispersibility is high, the primary particles are less likely to aggregate, and moldability and processability can be improved. Due to the combination of these properties, the solid carbon dioxide capture material of the present invention can fix carbon dioxide in a temperature range from room temperature to 200°C and capture it by heating at 50°C to 200°C, and has excellent fixation and capture performance.

[0012] In the solid carbon dioxide recovery material according to the present invention, the hardness is 3 kgf / mm ２ ~30 kgf / mm ２ and the axial ratio is preferably 1 to 5.

[0013] In this way, when packed in an adsorption tower or the like, the material is less likely to break due to gravity or friction caused by the flow of exhaust gas, etc., and gases such as exhaust gas can easily flow through it.

[0014] In the solid carbon dioxide recovery material according to the present invention, the powder pH value is preferably 8 to 14.

[0015] In this way, since the solid carbon dioxide capture material according to the present invention is basic, it becomes easier to capture carbon dioxide, which is weakly acidic.

[0016] In the solid carbon dioxide recovery material according to the present invention, the molar ratio of Na / Fe in the sodium ferrite is preferably 0.7 to 1.3.

[0017] Since the molar ratio of Na / Fe is 0.7 to 1.3, a large amount of sodium ferrite crystal phase can be contained, resulting in good carbon dioxide fixation and recovery performance.

[0018] The solid carbon dioxide recovery material according to the present invention preferably contains the organic binder, and the organic binder is preferably a polymer material selected from polystyrene, polyethylene, polypropylene, nitrile butadiene, silicone, fluororesin, and cellulose.

[0019] Use of the organic binder makes it possible to form a compact containing a high concentration of sodium ferrite, thereby improving the carbon dioxide fixation and recovery performance.

[0020] The solid carbon dioxide recovery material according to the present invention preferably contains the inorganic binder, and the inorganic binder is an inorganic material containing one or more of Na, Li, K, Ca, Mg, Si, Al, Ca, Fe, and Zn.

[0021] Use of the inorganic binder makes it possible to form a compact containing a high concentration of sodium ferrite, thereby improving the carbon dioxide fixation and recovery performance.

[0022] The method for producing a solid carbon dioxide recovery material according to the present invention is characterized by comprising the steps of: causing a solid-state reaction between a material containing iron oxide and an alkaline compound containing sodium; and kneading and shaping the powder obtained by the solid-state reaction with an organic binder or an inorganic binder.

[0023] In the method for producing a carbon dioxide fixation and capture material according to the present invention, solids are mixed and reacted by transferring elements without the intervention of a solvent. This eliminates the need for a solvent as a reaction mother liquor, thereby reducing waste, such as that generated by a liquid-phase reaction. In particular, solid-phase reactions at low temperatures can result in extremely high-concentration reactions, reducing energy costs. Therefore, according to the method for producing a carbon dioxide fixation and capture material according to the present invention, carbon dioxide can be fixed at a temperature range from room temperature to 200°C, and the fixed carbon dioxide can be recovered with high efficiency by heating at 50°C to 200°C, making it possible to produce a carbon dioxide capture material with excellent fixation and capture performance.

[0024] The solid carbon dioxide capture material according to the present invention can fix carbon dioxide in a temperature range from room temperature to 200°C, and can be highly efficiently captured by heating at 50°C to 200°C, providing excellent carbon dioxide fixation and capture performance.

[0025] 1 shows the results of thermogravimetric analysis after carbon dioxide is absorbed by the solid carbon dioxide recovery material obtained in Example 1. FIG. 2 shows the results of thermogravimetric analysis after carbon dioxide is absorbed by the solid carbon dioxide recovery material obtained in Example 10.

[0026] DETAILED DESCRIPTION OF THE INVENTION The following description of preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its uses.

[0027] First, a solid carbon dioxide capture material according to one embodiment of the present invention will be described.

[0028] The solid carbon dioxide capture material according to this embodiment contains 50% to 99% by weight of sodium ferrite and 1% to 50% by weight of an organic binder or an inorganic binder. When the weight percentages are within this range, the solid carbon dioxide capture material according to this embodiment can form a compact containing a high concentration of sodium ferrite while maintaining the carbon dioxide fixation and capture performance that sodium ferrite inherently has.

[0029] The solid carbon dioxide capture material according to this embodiment has an average particle size of 1 mm to 10 mm and a specific surface area of ​​1 m ２ / g to 50m ２ / g. If the average particle size is less than 1 mm, when the solid carbon dioxide recovery material according to this embodiment is filled into an adsorption tower or the like, the gaps between the powder particles become small, resulting in a large pressure loss in the adsorption tower. This can lead to clogging in the adsorption tower. If the average particle size exceeds 10 mm, the contact rate between the sodium ferrite and carbon dioxide decreases, resulting in a low carbon dioxide fixation recovery performance. The average particle size of the solid carbon dioxide recovery material is preferably 2 mm to 8 mm. In addition, if the specific surface area is 1 m ２ If the specific surface area is less than 50 m / g, the carbon dioxide contained in the gas is less likely to come into contact with the carbon dioxide, and the carbon dioxide fixation and recovery performance is reduced. ２ If the specific surface area of ​​the solid carbon dioxide capture material exceeds 2 m / g, industrial production becomes difficult. ２ / g to 30m ２ / g is preferred.

[0030] In the solid carbon dioxide recovery material according to this embodiment, the axial ratio of the average major axis diameter to the average minor axis diameter of the primary particles of sodium ferrite contained therein (average major axis diameter / average minor axis diameter) is preferably 1 to 2. If the axial ratio exceeds 2, the primary particles tend to aggregate, making it difficult to maintain high dispersibility of the sodium ferrite. Furthermore, the axial ratio cannot be smaller than 1. The axial ratio of the primary particles of sodium ferrite contained therein is more preferably 1.1 to 1.9.

[0031] The solid carbon dioxide collection material according to this embodiment has a hardness of 3 kgf / mm ２ ~30 kgf / mm ２ If the hardness is within the above range, when the carbon dioxide capture material according to this embodiment is packed into an adsorption tower or the like, it is less likely to break due to friction caused by gravity or the flow of exhaust gas, etc., and gases such as exhaust gas can easily flow through it.

[0032] The shape of the solid carbon dioxide capture material according to this embodiment is not particularly limited, but is preferably cylindrical, spindle-shaped, rectangular, cube-shaped, spherical, or the like. The axial ratio is the length of the solid carbon dioxide capture material divided by the length of its major axis from its minor axis, and is preferably 1 to 5. If the axial ratio exceeds 5, voids are likely to form when the material is packed into an adsorption tower. Furthermore, the axial ratio cannot be less than 1. More preferably, it is 1.5 to 4.

[0033] The solid carbon dioxide collection material according to this embodiment preferably has a powder pH value of 8 to 14. When the powder pH value is 8 to 14, the solid carbon dioxide collection material according to this embodiment becomes basic and easily captures carbon dioxide, which is weakly acidic.

[0034] In the solid carbon dioxide capture material according to this embodiment, the molar ratio of Na / Fe of the sodium ferrite is preferably 0.7 to 1.3. When the molar ratio is within this range, a large amount of the sodium ferrite crystalline phase can be contained, resulting in good carbon dioxide capture performance.

[0035] The organic binder according to this embodiment is preferably a polymer material selected from polystyrene, polyethylene, polypropylene, nitrile butadiene, silicone, fluororesin, and cellulose. The organic binder has excellent moldability, making it possible to form a molded body containing a high concentration of sodium ferrite, thereby improving the carbon dioxide fixation and recovery capacity.

[0036] The organic binder according to this embodiment preferably has a weight-average molecular weight of 1,000 to 100,000. If the weight-average molecular weight is less than 1,000, the molded body may be too soft, resulting in reduced strength. If the weight-average molecular weight exceeds 100,000, the organic binder may be too hard, making it difficult to form a molded body.

[0037] The inorganic binder according to this embodiment is preferably an inorganic material containing one or more of Na, Li, K, Ca, Mg, Si, Al, Ca, Fe, and Zn. The inorganic binder has excellent moldability, making it possible to form a molded body containing a high concentration of sodium ferrite, thereby improving the carbon dioxide fixation and recovery capacity.

[0038] The inorganic binder is an inorganic material containing one or more of Na, Li, K, Ca, Mg, Si, Al, Ca, Fe, and Zn, and is a fluid inorganic material such as silicate, metal phosphate, metal alcoholate, organopolysiloxane, organic-inorganic composite polymer, alumina sol, synthetic mica, phosphonitrile chloride, or cement, which is kneaded with sodium ferrite, formed into a suitable size, and subjected to drying with the application of heat energy, etc., to form an inorganic solid that serves as a binder.

[0039] Examples of silicates include water-soluble silicates such as sodium silicate, potassium silicate, lithium silicate, and ammonium silicate, as well as colloidal silica and organic metal siliconates. Examples of metal phosphates include aluminum phosphate, magnesium phosphate, calcium phosphate, iron phosphate, and zinc phosphate. Examples of metal alcoholates include alcoholates of silicon, aluminum, tin, titanium, and zirconium. Examples of organopolysiloxanes include silicone and alkyl silicates such as ethyl silicate, butyl silicate, phenyl silicate, octyl silicate, and lauryl silicate. Examples of organic-inorganic composite polymers include mixtures such as emulsion mixtures and aqueous resin mixtures, and graft compounds such as organic polymer grafts to glass or minerals. Examples of alumina sols include feathery particles and granular particles. Examples of synthetic mica include KMg ３ AlSi ３ O １０ F ２ It is a silicate mineral represented by the formula: K is Na, Ca, Sr, Ba, and part of Mg is Al, Fe ２＋ Examples include those in which Al is substituted with Zn, Be, B, Co, Mn, Li, or Zn, and those in which Al is substituted with Zn, Be, B, Co, Mn, Li, or Zn, and those in which Al is substituted with Zn, Be, B, Co, or Fe. Phosphonyl chloride includes various compounds as polyphosphazene derivatives. Examples of cement include polytran cement and alumina cement.

[0040] The solid carbon dioxide capture material according to this embodiment can selectively adsorb and fix carbon dioxide from a gas containing carbon dioxide. The adsorption temperature is between room temperature and the exhaust gas outlet temperature, approximately 10°C to 200°C. Because no additional external heating is required, the energy cost required for adsorption can be kept low (this is the carbon dioxide fixation process).

[0041] The solid carbon dioxide capture material according to this embodiment preferably captures carbon dioxide by desorbing the carbon dioxide captured in the carbon dioxide fixation step described above in a gas atmosphere that does not contain carbon dioxide at a temperature of 50° C. to 200° C. By keeping the desorption temperature at a low level of 200° C. or less, the energy cost required for desorption can be kept low (the carbon dioxide capture step).

[0042] Next, a method for producing a solid carbon dioxide capture material according to one embodiment of the present invention will be described.

[0043] The solid carbon dioxide recovery material according to this embodiment is manufactured by carrying out a step of causing a solid-state reaction between a material containing iron oxide and an alkaline compound containing sodium, and a step of kneading and shaping the powder obtained by the solid-state reaction with an organic binder or an inorganic binder.

[0044] By subjecting a material containing iron oxide to a solid-state reaction with an alkali compound containing sodium, sodium ferrite with the ability to adsorb and desorb carbon dioxide can be produced without using a solvent. Furthermore, a feature of solid-state reactions is that the crystal growth of sodium ferrite tends to be isotropic, which tends to suppress the axial ratio of the primary particles. Kneading this sodium ferrite with an organic or inorganic binder, extruding, and firing or drying tends to form a compact containing a high concentration of sodium ferrite. This improves the carbon dioxide capture performance, making it preferable as a solid carbon dioxide capture material.

[0045] In a specific production method, first, iron oxide and a sodium source powder are mixed and pulverized, and then calcined to obtain sodium ferrite particles. The obtained sodium ferrite particles are then kneaded with an organic binder or an inorganic binder using a kneader such as a twin-arm kneader, a screw kneader, a Muller mill, a plow mixer, or a planetary mixer, and molded using an extruder such as a screw extruder or a roller extruder. The resulting mixture is then dried or calcined to obtain a solid carbon dioxide recovery material. Calcination may be performed using steam heating, microwave heating, ultrasonic heating, or the like, in addition to conventional calcination.

[0046] Examples of the organic binder include polymeric materials selected from polystyrene, polyethylene, polypropylene, nitrile butadiene, silicone, fluororesin, and cellulose. Examples of the inorganic binder include inorganic materials containing one or more of Na, Li, K, Ca, Mg, Si, Al, Ca, Fe, and Zn. These inorganic binders include silicates, metal phosphates, metal alcoholates, organopolysiloxanes, organic-inorganic composite polymers, alumina sol, synthetic mica, phosphonitrile chloride, and cement. These inorganic binders are kneaded with sodium ferrite, molded into a suitable size, and then dried with thermal energy to form an inorganic solid that functions as a binder. The content of the organic or inorganic binder is preferably 1% by weight to 50% by weight. As described above, the formation of a molded body containing a high concentration of sodium ferrite improves the carbon dioxide fixation and recovery capacity.

[0047] The material containing iron oxide is not particularly limited, but examples thereof include hematite, magnetite, maghemite, and goethite.

[0048] The sodium-containing compound is not particularly limited, and examples thereof include sodium nitrite, sodium hydroxide, sodium oxide, sodium carbonate, etc. However, when considering industrial use, sodium nitrite, sodium sulfate, etc., which may generate toxic nitrous acid gas, sulfurous acid gas, etc. during production, should be avoided.

[0049] In general, solid-phase reactions are synthesis methods in which solids are mixed and elements are transferred and reacted without the use of a solvent. Because no solvent is used as the reaction mother liquid, waste such as solvents that would be generated in a liquid-phase reaction can be reduced. Furthermore, in the case of solid-phase reactions at low temperatures, which is a feature of the present invention, extremely high-concentration reactions can be achieved, thereby reducing energy costs. Furthermore, because there is no need for the high-concentration reactions or washing, a high yield of the product can be expected.

[0050] A typical embodiment of the present invention is as follows.

[0051] The sodium ferrite particles of the solid carbon dioxide recovery material according to the present invention and the elements in the raw materials thereof (excluding oxygen) were analyzed using a scanning X-ray fluorescence analyzer ZSX Primus II manufactured by Rigaku.

[0052] The composition of the inorganic components of the solid carbon dioxide recovery material according to the present invention was determined by crushing the solid carbon dioxide recovery material in a mortar and forming pellets, and then using a BRUKER D8 ADVANCE fully automatic multipurpose X-ray diffractometer. This identified the material as containing α-sodium ferrite, and when an inorganic binder was used as the binder, it was also identified as containing the inorganic binder.

[0053] The composition of the organic component of the solid carbon dioxide recovery material according to the present invention was determined to be the same as that of the added organic binder when the solid carbon dioxide recovery material was crushed in a mortar, mixed with potassium bromide, and pelletized, and then identified using a portable FT-IR (Fourier transform infrared spectrophotometer) "Niclet iS5" manufactured by Thermo Scientific.

[0054] When an organic binder is used as the binder, the contents of sodium ferrite and organic binder contained in the solid carbon dioxide recovery material according to the present invention were determined by crushing the solid carbon dioxide recovery material in a mortar, and heating a portion of it from room temperature to 200°C using a Hitachi High-Technologies STA7000 simultaneous differential thermal and thermogravimetric analyzer, with the portion that lost weight due to heat being the organic binder component and the remaining portion being the sodium ferrite portion, which is an inorganic material.

[0055] The average particle size of the solid carbon dioxide recovery material according to the present invention was determined by measuring the major and minor axes of 80 particles using a vernier caliper and averaging the measurements.

[0056] The BET specific surface area of ​​the solid carbon dioxide recovery material according to the present invention was measured by the BET method using nitrogen and a Multisorb-16 manufactured by QUANTA CHROME.

[0057] The hardness of the solid carbon dioxide recovery material according to the present invention was determined by measuring the average crushing hardness of 80 grains using a digital force gauge ZP-500N manufactured by Imada.

[0058] The hardness of the solid carbon dioxide recovery material according to the present invention was evaluated according to the following three levels: Good: Crushing hardness is 10 kgf / mm ２ △: Crushing hardness is 3 kgf / mm or more ２ More than 10 kgf / mm ２ x: Crushing hardness is less than 3 kgf / mm ２ Less than

[0059] The pH value of the solid carbon dioxide recovery material according to the present invention was measured by weighing 5 g of sample into a 300 ml Erlenmeyer flask, adding 100 ml of boiled pure water, heating and maintaining the boiling state for about 5 minutes, then plugging the flask and allowing it to cool to room temperature, adding water equivalent to the weight loss, plugging it again, shaking for 1 minute, and leaving it to stand for 5 minutes. The pH of the resulting supernatant was then measured in accordance with JIS Z8802-7, and the value obtained was taken as the pH value.

[0060] The molar ratio of Na / Fe of the sodium ferrite contained in the solid carbon dioxide recovery material according to the present invention was determined by crushing the solid carbon dioxide recovery material in a mortar, pelletizing it, and then performing elemental analysis (excluding oxygen) using a scanning X-ray fluorescence analyzer ZSX Primus II manufactured by Rigaku Corporation.

[0061] The axial ratio of the sodium ferrite contained in the solid carbon dioxide recovery material according to the present invention was determined by measuring the average major axis diameter and the average minor axis diameter of 350 primary particles shown in a micrograph taken with a Hitachi High-Technologies S-4800 scanning electron microscope, and expressing the ratio of the average major axis diameter to the average minor axis diameter (average major axis diameter / average minor axis diameter).

[0062] The average primary particle size of the sodium ferrite particles contained in the solid carbon dioxide recovery material according to the present invention is shown as the average value of the average major axis diameter and the average minor axis diameter.

[0063] In order to investigate the carbon dioxide fixation and recovery capacity of the solid carbon dioxide recovery material according to the present invention, 1.00 parts by weight of the sample was placed on a combustion boat and inserted into an acrylic pipe equipped with inlet and outlet piping. A (carbon dioxide + nitrogen) mixed gas adjusted to a humidity range of 20 to 100% and a carbon dioxide concentration range of 1 to 100 vol% was introduced from the inlet at 500 mL / min, and the amount of carbon dioxide adsorbed after 2 hours was measured using a Hitachi High-Technologies STA7000 simultaneous differential thermal and thermogravimetric analyzer, by heating from room temperature to 200°C, and the amount of carbon dioxide fixed and recovered was determined from the loss on heat.

[0064] <Method for manufacturing a solid carbon dioxide recovery material using an organic binder> Example 1 Iron oxide fine particles 1 (Toda Kogyo 100ED, hematite, specific surface area 11 m) ２ The sodium nitrite particles as the sodium raw material were weighed out so that the molar ratio of Na / Fe was 1.0 (Na / Fe = 1.0) and mixed and pulverized in a sample mill. The mixed and pulverized material was placed in a crucible and fired at 400°C for 16 hours. Thereafter, the mixture was cooled to room temperature and pulverized in a sample mill to obtain sodium ferrite particles. The BET specific surface area of ​​the obtained sodium ferrite particles was 4.0 m ２ / g. Quantification of the primary particles using a scanning electron microscope revealed an average major axis diameter of 0.7 μm, an average minor axis diameter of 0.4 μm, an average primary particle diameter of 0.55 μm, and an aspect ratio of 1.8. The powder pH was relatively high at 13.8. 90 parts by weight of the obtained sodium ferrite particle powder, 10 parts by weight of polystyrene (weight average molecular weight 12,000), and 20 parts by weight of methyl ethyl ketone were kneaded in a twin-arm kneader. This was extruded using a roller extruder (mesh opening 1 mm) and rotated in a spherical granulator to obtain cylindrical pellets with a diameter of 1 mm and a length of 3 mm. This was dried in a vacuum dryer at 80°C for 16 hours to obtain a solid carbon dioxide recovery material. The obtained solid carbon dioxide recovery material was pulverized and qualitatively analyzed by X-ray diffraction, which revealed that it was sodium ferrite and a resin component. Furthermore, qualitative analysis by FT-IR revealed that the resin component was polystyrene. Furthermore, this pulverized material was heated in a Hitachi High-Technologies STA7000 thermogravimetric differential thermal analyzer, and the thermally lost portion was determined to be the organic binder component, while the remaining portion was determined to be the sodium ferrite portion, which is an inorganic material. The sodium ferrite content was 90% and the polystyrene content was 10%. The BET specific surface area of ​​this solid carbon dioxide recovery material was 4 m ２ The minor axis was 1 mm, the major axis was 3 mm, the aspect ratio was 3, and the average particle size was 2 mm. The powder pH was 13.

[0065] The hardness of the obtained solid carbon dioxide recovery material was 10 kgf / mm ２ From these results, it is clear that when the carbon dioxide capture material according to Example 1 is packed into a carbon dioxide adsorption tower or the like, it is less likely to break and gases such as exhaust gases can easily pass through it.

[0066] The molar ratio of Na / Fe in the sodium ferrite contained in the obtained solid carbon dioxide recovery material was 1.0, which was the same as the charging ratio of the raw materials.

[0067] To examine the carbon dioxide fixation and recovery performance of the obtained solid carbon dioxide recovery material, 1.00 parts by weight of the sample was placed on a No. 2 combustion boat (12 x 60 x 9 mm) and aerated with a model combustion exhaust gas of 500 mL / min for 2 hours. Generally, the exhaust gas produced when fuel is burned in the atmosphere is composed of a maximum of 80 vol% nitrogen, 20 vol% carbon dioxide, and a relative humidity of 80 to 100% RH. Therefore, at room temperature 25 ° C, 400 mL / min of nitrogen and 100 mL / min of carbon dioxide were mixed, and this was bubbled into water to produce a model exhaust gas of 20 vol% carbon dioxide and a relative humidity of 80% RH.

[0068] 10 mg of the sample after aeration was weighed, and using a thermogravimetric analyzer (TG), the sample was heated to 200 ° C. at 10 ° C. / min while aerating with dry air at 300 mL / min, and the desorption temperature and amount of carbon dioxide adsorbed on the sample were measured. A measurement chart with the sample temperature on the horizontal axis is shown in Figure 1. The TG curve is the weight percent of the remaining sample at each temperature when the initial value is 100 wt%, and the amount of sample loss was considered to be due to the release of carbon dioxide. The DTG curve is a differential curve of the TG curve, and the temperature at which the DTG curve reaches its maximum value was considered to be the desorption temperature of carbon dioxide. The DTA curve showed a downward convex curve, and it was found that an endothermic reaction was occurring around 114 ° C. This was determined as NaHCO ３ When quantified assuming that this was thermal decomposition, the carbon dioxide desorption temperature was 114°C and the amount of carbon dioxide desorbed was 17% by weight based on the solid content of the sample, demonstrating excellent carbon dioxide fixation and recovery performance.

[0069] Furthermore, the sample after aeration was reprepared and weighed, which was 1.27 parts by weight, confirming an increase in mass of 27% by weight. X-ray diffraction analysis of the surface of this sample revealed that 79% by weight of Na １－ｘ FeO ２ and 21 wt% NaHCO ３It was confirmed that carbon dioxide was fixed in the sodium ferrite component. Furthermore, when this sample was heated in an electric furnace at 120°C for 1 hour and the weight was measured, it was found to be 1.10 parts by weight, and it was found that 0.17 parts by weight (17% by weight of the solid carbon dioxide recovery material) of carbon dioxide could be adsorbed and desorbed in this cycle. When X-ray diffraction was measured on the surface of this sample, it was found that 90% by weight of Na １－ｘ FeO ２ and 10 wt% Na ２ CO ３ It was confirmed that. Furthermore, when this sample was contacted with carbon dioxide in the same manner as above, the amount increased to 1.27 parts by weight, and when heated, the amount decreased to 1.10 parts by weight, and 0.17 parts by weight (17% by weight relative to the solid carbon dioxide capture material) of carbon dioxide was adsorbed and desorbed. This operation was repeated 10 times, and it was confirmed that there was no change in the increase or decrease in mass. This made it clear that the solid carbon dioxide capture material of Example 1 has excellent carbon dioxide fixation and capture performance, particularly excellent repeatability.

[0070] Examples 2 to 9 Solid carbon dioxide recovery materials according to Examples 2 to 9 were obtained in the same manner as in Example 1, except that the types and amounts of the iron raw material, sodium source, and organic binder were variously changed.

[0071] The production conditions in these examples are shown in Table 1, the properties of the obtained solid carbon dioxide recovery materials are shown in Table 2, and the effects are shown in Table 3.

[0072] Comparative Example 1 100 parts by weight of the sodium ferrite particles obtained in Example 1 were granulated at 40 rpm in a tumbling granulator while adding a small amount of a 1% aqueous carboxymethyl cellulose solution, and the granules were placed in a crucible and subjected to a solid-phase reaction at 400°C for 16 hours in a nitrogen gas flow. The mixture was then cooled to room temperature to obtain a solid carbon dioxide recovery material. The obtained solid carbon dioxide recovery material was pulverized and qualitatively analyzed by X-ray diffraction, revealing that it was sodium ferrite. Furthermore, fluorescent X-ray analysis revealed that the sodium ferrite content was 100%. The BET specific surface area of ​​this solid carbon dioxide recovery material was 4 m ２ The minor axis was 4 mm, the major axis was 9 mm, the average particle size was 6.5 mm, and the powder pH was 10.

[0073] The hardness of the obtained solid carbon dioxide recovery material was 1 kgf / mm ２ From these results, it is clear that when carbon dioxide capture material is packed into a carbon dioxide absorption tower or the like, it is difficult to pack because it is easily broken due to gravity and friction caused by the flow of exhaust gas, and its shape is irregular.

[0074] The production conditions for this comparative example are shown in Table 1, the properties of the obtained solid carbon dioxide recovery material are shown in Table 2, and the effects are shown in Table 3.

[0075]

[0076]

[0077]

[0078] As described above, it is clear that the solid carbon dioxide capture material according to the present invention is excellent in adsorbing and capturing carbon dioxide. Furthermore, the solid capture material is made by granulating sodium ferrite particles, which are solids with carbon dioxide capture capacity, into millimeter-sized particles using an organic binder, and has high hardness, so that it can be packed directly into a carbon dioxide adsorption tower.

[0079] <Method for producing a solid carbon dioxide recovery material using an inorganic binder> Example 10 Iron oxide fine particles 1 (Toda Kogyo 100ED, hematite, specific surface area 11 m) ２ The sodium nitrite particles as the sodium raw material were weighed out so that the molar ratio of Na / Fe was 1.0 (Na / Fe = 1.0) and mixed and pulverized in a sample mill. The mixed and pulverized material was placed in a crucible and fired at 400°C for 16 hours. Thereafter, the mixture was cooled to room temperature and pulverized in a sample mill to obtain sodium ferrite particles. The BET specific surface area of ​​the obtained sodium ferrite particles was 4.0 m ２ / g. Quantification of the primary particles using a scanning electron microscope revealed that the average major axis diameter was 0.7 μm, the average minor axis diameter was 0.4 μm, the average primary particle diameter was 0.55 μm, and the axial ratio was 1.8. The powder pH was relatively high at 13.8. 90 parts by weight of the obtained sodium ferrite particle powder, 10 parts by weight of sodium silicate, and 10 parts by weight of water were kneaded in a twin-arm kneader. This was extruded using a roller extruder (mesh opening 1 mm) and rotated in a spherical granulator to obtain cylindrical pellets with a diameter of 1 mm and a length of 3 mm. This was fired in a firing furnace at 200°C for 16 hours to produce a solid carbon dioxide recovery material. The obtained solid carbon dioxide recovery material was pulverized and qualitatively analyzed by X-ray diffraction, revealing that it was 90% sodium ferrite and 10% sodium silicate. The BET specific surface area of ​​this solid carbon dioxide recovery material was 3 m ２ The minor axis was 1 mm, the major axis was 3 mm, the aspect ratio was 3, and the average particle size was 2 mm. The powder pH was 13.

[0080] The hardness of the obtained solid carbon dioxide recovery material was 10 kgf / mm ２ From these results, it is clear that when the carbon dioxide capture material according to Example 10 is packed into a carbon dioxide adsorption tower or the like, it is less likely to break and gases such as exhaust gases can easily pass through it.

[0081] The molar ratio of Na / Fe in the sodium ferrite contained in the obtained solid carbon dioxide recovery material was 1.0, which was almost the same as the charging ratio of the raw materials.

[0082] To examine the carbon dioxide fixation and capture performance of the obtained carbon dioxide capture material, 1.00 parts by weight of the sample was placed on a No. 2 combustion boat (12 x 60 x 9 mm) and aerated with a model combustion exhaust gas of 500 mL / min for 2 hours. Generally, the exhaust gas produced when fuel is burned in the atmosphere is composed of a maximum of 80 vol% nitrogen, 20 vol% carbon dioxide, and a relative humidity of 80% to 100% RH. Therefore, at room temperature 25 ° C, 400 mL / min of nitrogen and 100 mL / min of carbon dioxide were mixed, and this was bubbled into water to produce a model exhaust gas of 20 vol% carbon dioxide and a relative humidity of 80% RH.

[0083] 10 mg of the sample after aeration was weighed, and using a thermogravimetric analyzer (TG), the sample was heated to 200 ° C. at 10 ° C. / min while aerating with dry air at 300 mL / min, and the desorption temperature and amount of carbon dioxide adsorbed on the sample were measured. Figure 2 shows a measurement chart with the sample temperature on the horizontal axis. The TG curve is the weight percent of the remaining sample at each temperature when the initial value is 100 wt%, and the amount of sample loss was considered to be due to the release of carbon dioxide. The DTG curve is a differential curve of the TG curve, and the temperature at which the DTG curve reaches its maximum value was considered to be the desorption temperature of carbon dioxide. The DTA curve showed a downward convex curve, and it was found that an endothermic reaction was occurring around 108 ° C. This was determined as NaHCO ３ When quantified assuming that this was thermal decomposition, the carbon dioxide desorption temperature was 108°C and the amount of carbon dioxide desorbed was 18% by weight based on the solid content of the sample, demonstrating excellent carbon dioxide fixation and recovery performance.

[0084] Furthermore, the sample after aeration was reprepared and weighed, which was found to be 1.28 parts by weight, confirming a mass increase of 28% by weight. X-ray diffraction analysis of the surface of this sample revealed that 78% by weight of Na １－ｘ FeO ２ and 22 wt% NaHCO ３ It was confirmed that carbon dioxide was fixed in the sodium ferrite component. Furthermore, when this sample was heated in an electric furnace at 120°C for 1 hour and the weight was measured, it was found to be 1.10 parts by weight, and it was found that 0.18 parts by weight (17% by weight of the solid carbon dioxide recovery material) of carbon dioxide could be adsorbed and desorbed in this cycle. When X-ray diffraction was measured on the surface of this sample, it was found that 90% by weight of Na １－ｘ FeO ２ and 10 wt% Na ２ CO ３It was confirmed that. Furthermore, when this sample was contacted with carbon dioxide in the same manner as above, the amount increased to 1.28 parts by weight, and when heated, the amount decreased to 1.10 parts by weight, and 0.18 parts by weight (18% by weight relative to the solid carbon dioxide capture material) of carbon dioxide was adsorbed and desorbed. This operation was repeated 10 times, and it was confirmed that there was no change in the increase or decrease in mass. This made it clear that the solid carbon dioxide capture material of Example 10 has excellent carbon dioxide fixation and capture performance, particularly excellent repeatability.

[0085] Examples 11 to 23 Solid carbon dioxide recovery materials according to Examples 11 to 23 were obtained in the same manner as in Example 10, except that the types and amounts of the iron raw material, sodium source, and inorganic binder were variously changed.

[0086] The production conditions in these examples are shown in Table 4, the properties of the obtained solid carbon dioxide recovery materials are shown in Table 5, and the effects are shown in Table 6.

[0087] Comparative Example 1 The comparative example used was the same as the above-mentioned Comparative Example 1. The production conditions for this comparative example are shown in Table 4, the properties of the obtained solid carbon dioxide recovery material are shown in Table 5, and the effects are shown in Table 6.

[0088]

[0089]

[0090]

[0091] As described above, it is clear that the solid carbon dioxide capture material according to the present invention is excellent in adsorbing and capturing carbon dioxide. Furthermore, the solid capture material is made by granulating sodium ferrite particles, which are solids with carbon dioxide capture capacity, into millimeter-sized particles using an inorganic binder, and has high hardness, so that it can be packed directly into a carbon dioxide adsorption tower.

Claims

1. A solid carbon dioxide recovery material containing 50% by weight to 99% by weight of sodium ferrite and 1% by weight to 50% by weight of an organic binder or an inorganic binder, the material having an average particle size of 1 mm to 10 mm and a specific surface area of ​​1 m ２ / g to 50m ２ / g, A solid carbon dioxide recovery material, wherein the axial ratio of the average major axis diameter to the average minor axis diameter of primary particles of the sodium ferrite is 1 to 2.

2. Hardness is 3kgf / mm ２ ~30kgf / mm ２ The solid carbon dioxide capture material according to claim 1, wherein the axial ratio is 1 to 5.

3. The solid carbon dioxide recovery material according to claim 1 or 2, wherein the powder pH value is 8 to 14.

4. The solid carbon dioxide capture material according to claim 1 or 2, wherein the sodium ferrite has a molar ratio of Na / Fe of 0.7 to 1.

3.

5. The organic binder is included, 3. The carbon dioxide solid recovery material according to claim 1, wherein the organic binder is a polymer material selected from the group consisting of polystyrene, polyethylene, polypropylene, nitrile butadiene, silicone, fluororesin and cellulose.

6. The organic binder is included, 3. The carbon dioxide solid recovery material according to claim 1, wherein the organic binder has a weight average molecular weight of 1,000 or more and 100,000 or less.

7. The inorganic binder is included, The solid carbon dioxide capture material according to claim 1 or 2, wherein the inorganic binder is an inorganic material containing one or more of Na, Li, K, Ca, Mg, Si, Al, Ca, Fe, and Zn.

8. A step of reacting a material containing iron oxide with an alkali compound containing sodium in a solid phase; The method for producing a solid carbon dioxide capture material according to claim 1 or 2, further comprising the step of kneading the powder obtained by the solid-phase reaction with an organic binder or an inorganic binder and shaping the mixture.