Solid carbon dioxide recovery materials

Abstract

The present invention provides a solid carbon dioxide recovery material having durability capable of long-term use, particularly repeated use with a water-containing gas as an object, and for this purpose, the solid carbon dioxide recovery material of the present invention contains iron, sodium, and crystalline carbon, and more specifically, contains sodium ferrite, crystalline carbon, and at least one binder selected from the group consisting of amorphous carbon, polyamide-imide, polyester, epoxy resin, polyurethane, and acrylic resin.

Description

Technical Field

[0001] This invention relates to a solid recovery material for immobilizing carbon dioxide and a method for manufacturing the same, and more particularly to a solid recovery material containing sodium ferrite. Background Technology

[0002] In the past, research has been conducted on the recovery, storage, and utilization of carbon dioxide to reduce atmospheric emissions. Large-scale sources of carbon dioxide include coal-fired power plants, boilers in manufacturing plants, and kilns in cement plants that use coal, heavy oil, or natural gas as fuel. Additionally, blast furnaces in iron smelting plants that reduce iron oxide with coke, and transport vehicles such as cars, ships, and airplanes that use gasoline, heavy oil, or light oil as fuel can also be cited.

[0003] Patent Document 1 discloses a solid recovery material containing sodium ferrite and carbon dioxide, which can achieve a high concentration of sodium ferrite by adding organic or inorganic binders. Furthermore, Patent Document 1 discloses polystyrene, polyethylene, etc., as organic binders, and Na, Li, and K, etc., as inorganic binders. Existing technical documents Patent documents

[0004] Patent Document 1: International Publication No. 2022 / 259929 Summary of the Invention -The problem the invention aims to solve-

[0005] In order to make solid carbon dioxide recovery materials practical, in addition to performance such as carbon dioxide recovery rate, durability is also required.

[0006] The purpose of this invention is to provide a solid carbon dioxide recycling material that can be used for a long period of time. -Solutions for solving the problem-

[0007] This invention provides a solid carbon dioxide recycling material containing iron, sodium, and crystalline carbon. In addition, the crystalline carbon may be at least one substance selected from graphite, carbon nanotubes, acetylene black and calcined petroleum coke. The solid recycled material may further contain an adhesive. The adhesive may be at least one substance selected from amorphous carbon, polyamide, polyester, epoxy resin, polyurethane and acrylic resin. The adhesive may contain calcined asphalt. The total carbon content of the crystalline carbon and binder can be 10-70% by weight. The solid recycled material may contain sodium ferrite. The Fe composition ratio in solid recycled materials can be 5 to 50 by weight. -The Effects of the Invention-

[0008] The solid carbon dioxide recovery material described in this invention has water resistance and strength, thus possessing durability for long-term use. Detailed Implementation

[0009] The embodiments of the present invention will be described below. The following description of preferred embodiments is merely illustrative and is not intended to limit the present invention, its applicable methods, or its uses.

[0010] A solid carbon dioxide recovery material (hereinafter sometimes simply referred to as "solid recovery material") according to one embodiment of the present invention will be described.

[0011] The solid carbon dioxide recovery material involved in this embodiment contains iron (Fe), sodium (Na) and crystalline carbon.

[0012] The form of Fe contained in solid recycled materials is not particularly limited. In other words, Fe can be elemental or a compound, and its phase (α, β, γ, etc.) is also not limited. When solid recycled materials contain Fe in the form of a compound, the constituent elements of that compound other than Fe are not limited. In addition, solid recycled materials may contain one or more forms of Fe. For example, α-Fe, FeO, and / or Fe3O4 can be listed as forms of Fe.

[0013] The Fe content in the solid recycled material is preferably 5-50% by weight, more preferably 8-40% by weight, and even more preferably 11-30% by weight. If the composition ratio is within the above range, the strength is excellent.

[0014] The form of Na contained in solid recycled materials is not particularly limited, and it can contain one or more forms. For example, Na₂CO₃(H₂O) and / or Na₂CO₃ can be listed.

[0015] The Na composition of the solid recycled material is preferably 1 to 20% by weight, more preferably 1.5 to 15% by weight, and even more preferably 2 to 10% by weight. If the composition is within the above range, the carbon dioxide recovery rate is good.

[0016] The Fe and Na contained in solid recycled materials can form sodium ferrite (NaFeO2). In other words, solid recycled materials can contain sodium ferrite. There is no particular limitation on the form of sodium ferrite; it can contain one or more forms. For example, sodium ferrite can be in the forms of α-NaFeO2 and / or β-NaFeO2, etc.

[0017] Furthermore, in the absence of water vapor in the gas, the reaction between sodium ferrite and carbon dioxide is NaFeO₂ + 1 / 2CO₂ → 1 / 2Na₂CO₃ + 1 / 2Fe₂O₃; in the presence of water vapor, the reaction is NaFeO₂ + CO₂ + 1 / 2H₂O → NaHCO₃ + 1 / 2Fe₂O₃. Moreover, by placing the solid recycled material after reacting with carbon dioxide in a carbon dioxide-free atmosphere at a specified temperature, carbon dioxide can be desorbed. Thus, the solid recycled material can repeatedly adsorb, fix, and then desorb carbon dioxide.

[0018] When the solid recovery material contains sodium ferrite, the Na / Fe molar ratio of sodium ferrite is preferably 0.7 to 1.3. Within this molar ratio range, a large amount of sodium ferrite crystalline phase can be contained, thus resulting in good carbon dioxide fixation and recovery performance.

[0019] When the solid recovery material contains sodium ferrite, the pH value of the sodium ferrite powder is preferably 8 to 14. If the powder pH value is 8 to 14, the solid carbon dioxide recovery material involved in this embodiment becomes alkaline, making it easier to capture weakly acidic carbon dioxide.

[0020] When the solid recycled material contains sodium ferrite, the axial ratio (average major axis diameter / average minor axis diameter) of the primary sodium ferrite particles is preferably 1 to 2. If this axial ratio is within the above range, the primary sodium ferrite particles are less likely to aggregate and can exhibit high dispersibility. The axial ratio of the primary sodium ferrite particles is more preferably 1.1 to 1.9.

[0021] The crystalline carbon contained in the solid recycled material is preferably selected from at least one substance chosen from graphite, carbon nanotubes, acetylene black, and calcined petroleum coke, and two or more may be used in combination. Crystalline carbon acts as an aggregate that imparts strength to the solid recycled material and maintains its shape. Furthermore, since solid recycled materials containing crystalline carbon are water-resistant, they are preferably used for treating water-containing gases. In addition, crystalline carbon can impart a structure to the solid recycled material that allows carbon dioxide to contact the Fe and Na (including compounds such as sodium ferrite) contained in the solid recycled material, specifically imparting fine pores to the solid recycled material.

[0022] Solid recycled materials preferably contain a binder. The binder maintains the shape of the solid recycled material by bonding the elements constituting the solid recycled material, such as Fe, Na, and crystalline carbon. The solid recycled material preferably contains at least one of amorphous carbon and a polymer as a binder, and may contain one or more binders. Examples of polymers include polyamide-imide, polyester, epoxy resin, polyurethane, and acrylic resin. Examples of amorphous carbon include calcined asphalt. Asphalt is a byproduct of petroleum or coal tar.

[0023] By incorporating crystalline carbon and the aforementioned binder, the solid recycled material can maintain its structure even with long-term, repeated use. Typically, the solid recycled material is filled into a container during use. A structure having a container and multiple portions of solid recycled material filled within that container is called an adsorption tower. In the adsorption tower, the target gas passes through the gaps between the solid recycled materials. If the solid recycled material disintegrates, the pressure loss increases due to the narrowing or collapse of the gas flow path.

[0024] When the binder is a polymer, its weight-average molecular weight is preferably between 1,000 and 100,000. If the weight-average molecular weight is less than 1,000, the molded article will be too soft, and its strength may decrease. If the weight-average molecular weight is greater than 100,000, the organic binder will be too hard, and it may be difficult to form the molded article.

[0025] In the solid recycled material, the total carbon content of crystalline carbon and binder is preferably 10-70% by weight, more preferably 15-65% by weight, and even more preferably 20-60% by weight. By keeping this composition ratio within the above range, high strength and water resistance can be obtained.

[0026] Preferably, the solid recycled material contains iron (Fe), sodium (Na) and crystalline carbon, with the remainder being oxygen.

[0027] The solid recovery material preferably has a particle size of 1 mm to 10 mm. Particle size is the average of the major and minor axes of the solid recovery material. If the particle size is 1 mm or larger, a gap sufficient for the target gas to pass through can be ensured between the solid recovery materials in the adsorption tower, thus suppressing and reducing pressure loss to a practical level. By making the particle size less than 10 mm, the contact rate between Fe and carbon dioxide is increased, thus enabling efficient recovery of carbon dioxide. The particle size of the solid recovery material is more preferably 2 mm to 8 mm.

[0028] The shape of the solid recycled material is not particularly limited, but cylindrical, spindle-shaped, cuboid, dice-shaped, and spherical shapes are preferred.

[0029] The axial ratio of the solid recycled material, i.e., the ratio of the major axis length to the minor axis length, is preferably 1 to 5. If the axial ratio is 1 or higher, voids that form gas flow paths are easily formed between the solid recycled materials. On the other hand, if the axial ratio is 5 or lower, the void size is sufficient to allow effective contact between carbon dioxide and Fe and Na, and the voids are uniformly distributed throughout the adsorption tower. The axial ratio is more preferably 1.5 to 4.

[0030] The strength of the solid recovery material is preferably 20 N or more, more preferably 60 N or more, and even more preferably 100 N or more. The solid recovery material inside the adsorption tower, especially in the lower part, is subjected to pressure generated by the solid recovery material above. Furthermore, if the target gas flows through the adsorption tower, the solid recovery material is also subjected to pressure generated by that gas. If the strength is within the above range, the solid recovery material is less likely to pulverize, and the target gas, such as waste gas, can easily flow through the adsorption tower.

[0031] The porosity of the solid recovery material is preferably 20-80% by volume, more preferably 25-70% by volume, and even more preferably 30-65% by volume. If the porosity is within the above range, the carbon dioxide contained in the target gas can easily come into contact with the solid recovery material, thus enabling effective recovery of carbon dioxide.

[0032] The bulk density of the solid recycled material is preferably 0.4 g / cc or higher, more preferably 0.45 g / cc or higher. If the bulk density is within the above range, the packing properties in the adsorption tower are good. The upper limit of the bulk density is approximately 1 g / cc.

[0033] Next, an example of a method for manufacturing the aforementioned solid carbon dioxide recovery material will be described. The solid recovery material is not limited to the following manufacturing method.

[0034] The manufacturing method of solid recycled materials includes: a mixing process of mixing carbon dioxide absorbent containing Fe and Na with aggregate containing crystalline carbon, and a forming process of shaping the mixture.

[0035] The compound preferably contains 20 to 140 parts by weight of aggregate, relative to 100 parts by weight of carbon dioxide absorbent material.

[0036] In the mixing process, the Fe and Na raw materials can be sodium ferrite as described above. Materials such as binders can also be further added to the above materials. The mixture preferably contains 0 to 50 parts by weight of binder, more preferably 10 to 40 parts by weight of binder, relative to 100 parts by weight of carbon dioxide absorbent material. Additionally, liquids such as water and organic solvents can be added. Mixing equipment such as double-arm kneaders, screw kneaders, Muller mills, plow mixers, and planetary motion mixers can be used in the mixing process.

[0037] In the forming process, techniques such as punching, extrusion (screw, roller, etc.), rolling, cutting, and spheroidizing can be used individually or in combination. For example, an extrusion molding machine can be used to extrude the compound into shape and cut it into specified lengths.

[0038] The manufacturing method of solid recycled materials can be further improved by performing a drying process after molding to dry the molded material.

[0039] Alternatively, the manufacturing method of solid recycled materials can also include a firing process in which the shaped material is sintered. If a drying process is performed, the firing process can be carried out after the drying process. Firing is preferably carried out in a nitrogen atmosphere. It should be noted that, in addition to conventional firing, steam heating, microwave heating, ultrasonic heating, etc., can also be used. The firing temperature and time are appropriately set to obtain solid recycled materials with the desired strength. Firing depends on the type of aggregate and binder, and is preferably carried out at a temperature between 100°C and 1000°C. For example, when using asphalt as a binder, firing is preferably carried out at a temperature higher than its oil volatilization temperature, for example, preferably 500°C or higher.

[0040] It should be noted that the manufacturing method of solid recycled materials may further include a step of generating sodium ferrite, in which a material containing iron oxide and a material containing sodium undergo a solid-phase reaction. Specifically, sodium ferrite granules can be obtained by mixing and pulverizing the material containing iron oxide and the material containing sodium, calcining, and then appropriately pulverizing. Examples of materials containing iron oxide include hematite, magnetite, maghemite, and / or goethite. Examples of materials containing sodium include sodium nitrite, sodium hydroxide, sodium oxide, and / or sodium carbonate.

[0041] As described above, solid recycled materials can be used in adsorption towers. An adsorption tower includes a container and multiple solid recycled materials filled within the container. In the adsorption tower, the average particle size of the solid recycled materials is preferably 1 mm to 10 mm. The average particle size can be calculated as follows: the long axis and short axis of 80 particles are measured, and their average value is used to calculate the average particle size.

[0042] The size of the container and the amount of solid recycled material filled inside can be changed according to the usage conditions and purpose of the adsorption tower.

[0043] Solid recycling materials can selectively adsorb and fix carbon dioxide from gases containing carbon dioxide. During adsorption, the target gas is brought into contact with the solid recycling material. The preferred temperature for this process is approximately 20–80°C.

[0044] Carbon dioxide can be desorbed by placing solid recycled materials with fixed carbon dioxide at a temperature of about 50℃ to 200℃.

[0045] The desorbed solid recycled material can be reused for the adsorption and fixation of carbon dioxide, thus the solid recycled material can be reused. [Example]

[0046] Manufacturing of Solid Recycled Materials Examples 1-7, Comparative Example 1: Weigh the aggregate, binder, and sodium ferrite (NaFeO2) shown in Table 1 to achieve the weight ratio shown in Table 1, and mix them. Place the mixture in a kneader, add 100 parts by weight of water, and knead for 1 hour. After kneading, extrude the mixture into 2mm diameter pieces and cut them into 5mm lengths. After cutting, dry at 60°C for 12 hours, and then calcine in a nitrogen atmosphere furnace at 600°C for 3 hours to obtain solid recycled material.

[0047] Example 8: As shown in Table 1, the materials and weight ratios were set, and the mixture was kneaded without adding water. The firing temperature was set to 200°C. Otherwise, the solid recycled material was obtained by following the same steps as in Example 1.

[0048] Comparative Example 2: As shown in Table 1, the material and weight ratios are set, and no firing is performed. Otherwise, the solid recycled material is obtained by following the same steps as in Example 1.

[0049] Comparative Example 3: Without using aggregate, the material and weight ratios are set as shown in Table 1, and the solid recycled material is obtained by following the same steps as in Example 1.

[0050] [Table 1] *CNT: Carbon Nanotubes

[0051] <Analysis> (Crystallization) The compounds contained in the aggregates and binders of the solid recycled materials of the above embodiments and comparative examples are shown in Table 2. When the compounds contained in the aggregates and binders are carbon (C), their states (crystalline / amorphous) are shown in Table 2.

[0052] Solid recycled material was pulverized using a mortar and pestle. The crystallite size of the (002) plane was determined using the Scherrer equation with a fully automated multi-purpose X-ray diffractometer D8 ADVANCE (manufactured by BRUKER JAPAN CO., LTD.). Additionally, the average interplanar spacing d(002) was calculated using the Bragg equation. Crystalline carbon was considered to have an average interplanar spacing d(002) of 3.35–3.6 Å or a crystallite size of 20–400 Å.

[0053] Furthermore, for the adhesive, a separate sample was prepared by firing under the same conditions as the solid recycled material. This sample was then analyzed using the same apparatus as described above, and it was determined to be amorphous carbon due to the absence of crystalline peaks. Additionally, after removing Na and Fe components from the recycled material with hydrochloric acid, observation using a scanning electron microscope revealed the presence of carbon components other than crystalline carbon, indicating the presence of amorphous carbon.

[0054] [Table 2]

[0055] (Average particle size) The major and minor axes of 80 particles were measured using vernier calipers. Each solid recycled material was kept to the same size as when it was formed. The average value of the measurements is the average particle size.

[0056] (Porosity) According to Japanese Industrial Standard JIS R1655, the porosity of solid recycled materials is determined by mercury infiltration method.

[0057] (bulk density) The bulk density of solid recycled materials was determined according to Japanese Industrial Standard JIS Z2504.

[0058] [Table 3]

[0059] (Compound composition of solid recycled materials) Solid recycled materials were pulverized in a mortar and pestle, and the carbon dioxide absorbing components and aggregates were identified using the D8 ADVANCE fully automated multi-purpose X-ray diffractometer manufactured by BRUKER JAPAN CO., LTD.

[0060] (Elemental composition ratio of solid recycled materials) The pretreatment for elemental analysis and quantification, excluding carbon and oxygen, was performed as follows: The solid recycled material was pulverized in a mortar and pestle. One part by weight each of the solid recycled material and high-purity cellulose powder SpectoroBlend 44μm molowder (CHemplex Industries, inc.) as a forming agent were added, and the mixture was stirred using a rotary mixer. The mixture was then pressed into a powder with a diameter of 10 mm and a thickness of 1 mm. Elemental analysis and quantification, excluding carbon and oxygen, were performed using a Rigaku Corporation ZSX Primus II scanning fluorescence X-ray analyzer.

[0061] In addition, carbon was quantified using a carbon-sulfur analyzer (EMIA-920V2; HORIBA, Ltd.), and oxygen was quantified using an oxygen-nitrogen-hydrogen analyzer (EMGA-930; HORIBA, Ltd.).

[0062] [Table 4]

[0063] <Performance Evaluation> (Water resistance) Pour 100ml of pure water into a 200ml beaker and immerse 10g of solid recycled material in the water. After immersion, let it stand at 30℃ and visually observe the shape change of the solid recycled material over time. The water resistance is judged as follows: if the time to observe the shape change of the solid recycled material after immersion is less than 5 hours, it is unqualified; if it is more than 5 hours, it is qualified. The solid recycled materials in Examples 1-8 did not show any change even after immersion in water for more than one month.

[0064] (Carbon dioxide recovery rate) To evaluate the carbon dioxide fixation and recovery performance of the solid recovery material, the carbon dioxide recovery rate was determined as follows. A packed column (25 mm diameter × 500 mm height) was filled with solid recovery material to a height of 300 mm to serve as an adsorption tower. The system was adjusted to 40°C and 80% relative humidity, using GHSV for 490 h⁻¹. -1A mixture of 10 vol% carbon dioxide and 90 vol% nitrogen was introduced for 7 hours. Then, the packed column was heated to 150°C, and carbon dioxide was desorbed from the solid recovery material for 2 hours. The instantaneous concentration of desorbed carbon dioxide was measured using an infrared gas detector RI-557 (manufactured by RIKEN KEIKI CO., LTD.), and the carbon dioxide recovery was calculated based on the measurement results. Furthermore, the carbon dioxide recovery rate (wt%) was calculated as the amount recovered per unit weight of solid recovery material during packing.

[0065] (Average crushing strength) The strength of solid recycled materials was determined using an IMADA CO., LTD. ZP-500N digital force gauge. Pressure was applied to the long axis side of the cylindrical solid recycled material, and the strength of crushing the material was taken as the crushing strength, expressed in Newtons (N). The average crushing strength of 80 particles was taken as the average crushing strength. An average crushing strength of 100 N or more was considered excellent, 20 N or more but less than 100 N was considered good, and less than 20 N was considered unacceptable.

[0066] [Table 5]

[0067] The solid recycled materials obtained in Examples 1-7 contain Na, Fe, and crystalline carbon. Specifically, they contain Na₂CO₃(H₂O), Na₂CO₃, α-NaFeO₂, β-NaFeO₂, α-Fe, FeO, Fe₃O₄, and the aggregates listed in Table 4. The solid recycled materials obtained in Examples 1-7 also contain amorphous carbon. Furthermore, even after carbon dioxide adsorption and desorption, the phase composition of the compounds contained in the solid recycled materials remains unchanged compared to the above.

[0068] The solid recycled material obtained in Example 8 contains Na, Fe, and crystalline carbon. Specifically, it contains Na₂CO₃(H₂O), Na₂CO₃, α-NaFeO₂, and CNTs. The solid recycled material obtained in Example 8 also contains a polymer resin. Furthermore, even after adsorption and desorption of carbon dioxide, the phase composition of the compounds contained in the solid recycled material remains unchanged compared to the above.

[0069] On the other hand, the solid recycled materials obtained in Comparative Examples 1-3 contain Na and Fe. Specifically, Comparative Example 1 contains Na₂CO₃(H₂O), α-NaFeO₂, Fe₃O₄, and cordierite; Comparative Example 2 contains Na₂CO₃(H₂O), Na₂CO₃, α-NaFeO₂, and cellulose; and Comparative Example 3 contains Na₂CO₃(H₂O), Na₂CO₃, α-NaFeO₂, and β-NaFeO₂. 2、 α-Fe, FeO, and Fe3O4.

[0070] However, since the solid recycled materials of Comparative Examples 1-3 did not contain crystalline carbon, their water resistance was unsatisfactory. Furthermore, since the solid recycled material of Comparative Example 2 did not contain a binder, its average crushing strength was also poor.

[0071] As described above, the solid recycling material of the present invention, containing Na, Fe and crystalline carbon, has carbon dioxide recycling performance, high crushing strength and water resistance, thus achieving a durable effect. -Industry availability-

[0072] It is suitable as a solid material for carbon dioxide recovery. Due to its excellent durability, it can undergo repeated adsorption and desorption processes, and it also has industrial applications.

Claims

1. A solid carbon dioxide recovery material, wherein, The solid carbon dioxide recovery material contains iron, sodium, and crystalline carbon.

2. The solid carbon dioxide recovery material according to claim 1, wherein, The crystalline carbon is selected from at least one substance selected from graphite, carbon nanotubes, acetylene black, and calcined petroleum coke.

3. The solid carbon dioxide recovery material according to claim 1 or 2, wherein, The solid carbon dioxide recovery material also contains an adhesive.

4. The solid carbon dioxide recovery material according to claim 3, wherein, The adhesive is at least one substance selected from amorphous carbon, polyamide-imide, polyester, epoxy resin, polyurethane, and acrylic resin.

5. The solid carbon dioxide recovery material according to claim 3, wherein, The adhesive contains calcined asphalt.

6. The solid carbon dioxide recovery material according to claim 4, wherein, The total carbon content of the crystalline carbon and the binder is 10-70% by weight.

7. The solid carbon dioxide recovery material according to claim 1, wherein, The solid carbon dioxide recovery material contains sodium ferrite.

8. The solid carbon dioxide recovery material according to claim 1, wherein, The Fe composition ratio in the solid carbon dioxide recovery material is 5-50 by weight.

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