Method for capturing, storing and transporting carbon dioxide

Abstract

The invention discloses a method for capturing, storing and transporting carbon dioxide. According to the method, guanidine sulfate powder is used for selectively absorbing carbon dioxide or pure carbon dioxide in a gas mixture. When carbon dioxide is in contact with guanidine sulfate under a certain pressure, carbon dioxide reacts with guanidine sulfate to form a carbon dioxide-guanidine sulfate inclusion compound. According to the method, efficient and low-energy-consumption capture of carbon dioxide is achieved through guanidine sulfate powder, the obtained carbon dioxide and guanidine sulfate clathrate compound can achieve storage and transportation of carbon dioxide at normal temperature and normal pressure, the purity of carbon dioxide obtained through separation of the method is extremely high, and the purity of carbon dioxide can reach 100% theoretically.

Description

Technical Field

[0001] The invention relates to a method for capturing, storing and transporting carbon dioxide, in particular to a method for capturing, storing and transporting carbon dioxide using guanidine sulfate solid powder as an adsorbent. Background Art

[0002] Carbon capture, utilization and storage (CCUS) is one of the key technologies to address global climate change and is highly valued by countries around the world. Carbon dioxide is a major greenhouse gas and an important industrial product, widely used in chemical, welding, casting, food and preservation and other fields. Low-cost capture of carbon dioxide and its transportation to the required location can not only reduce carbon emissions, but also create economic value. In the industrial chain of CCUS, the storage and transportation of carbon dioxide is crucial and can make a huge contribution to reducing the impact of climate change. After capturing carbon dioxide from the production process, it needs to be safely and cost-effectively transported to the place of use or storage, and at the same time, high-purity carbon dioxide needs to be released in a controlled manner. At present, the storage and transportation of carbon dioxide is mainly in liquid phase, which is divided into normal temperature high-pressure gas cylinders and low-temperature low-pressure storage tanks. However, the existing technology faces its challenges and risks, and has the disadvantages of slow filling speed, low transportation efficiency, cumbersome operation, environmental pollution, and the need for special containers. The storage and transportation of carbon dioxide requires a more highly secure method to avoid leakage and other environmental problems.

[0003] In summary, the current carbon dioxide capture and post-capture transportation and storage technologies have risks such as high cost and low efficiency, which hinders the low-cost and efficient implementation of CCUC. Summary of the invention

[0004] In order to solve the above technical problems, the inventors have proposed a low-cost and efficient method for capturing, storing and transporting carbon dioxide. To this end, the present invention adopts the following technical solutions:

[0005] <1> A method for capturing, storing and transporting carbon dioxide, the method comprising: using guanidine sulfate powder to selectively absorb carbon dioxide in a gas mixture or pure carbon dioxide to obtain a carbon dioxide@guanidine sulfate sample.

[0006] <2> .according to <1> The method, wherein the selective absorption comprises contacting the guanidine sulfate powder with carbon dioxide gas at different pressures.

[0007] <3> .A method according to any one of the above items, wherein the time required for the contact depends on the carbon dioxide pressure, and the higher the pressure, the shorter the contact time required.

[0008] <4> .A method according to any one of the above items, wherein the time required for the contact also depends on the ambient temperature during the contact.

[0009] <5> . A method according to any one of the above, wherein the contacting is carried out at room temperature.

[0010] <6> .The method according to claim 1, wherein the method further comprises: heating the carbon dioxide@guanidine sulfate sample within a temperature range of 50-100°C to release high-purity carbon dioxide.

[0011] <7> . The method according to any one of the above items, wherein the method further comprises: the obtained guanidine sulfate is recycled for the next round of carbon dioxide adsorption.

[0012] <8> . A method according to any one of the above, wherein the method comprises:

[0013] The carbon dioxide@guanidine sulfate sample is stored and / or transported under normal temperature and pressure conditions.

[0014] <9> .A method according to any one of the above items, wherein the carbon dioxide@guanidine sulfate sample is stored in a plastic container or a glass container at room temperature for at least 30 days without carbon dioxide desorption.

[0015] <10> .A method according to any one of the above items, wherein the guanidine sulfate powder has a crystal structure parameter of: a=b=c=17.7640, α=β=γ=90°, a chemical formula of: [C(NH2)3]2SO4, and a CAS number of: 594-14-9.

[0016] The method of the present invention can directly store or transport carbon dioxide after it is captured, and no high-cost containers such as steel cylinders or low-temperature equipment are required during transportation. 60 times the volume of carbon dioxide can be stored at normal temperature and pressure. High-purity carbon dioxide can be released by heating at a relatively low temperature, and the purity of carbon dioxide can theoretically reach 100%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is the adsorption-desorption isotherm of solid guanidine sulfate powder in the range of 0-1.5 MPa at 25° C., and the mass percentage of carbon dioxide in the powder after adsorption of carbon dioxide is 17%, wherein the mass percentage refers to the ratio of the mass of carbon dioxide to the total mass of the carbon dioxide@guanidine sulfate sample;

[0018] Figure 2 It is the adsorption-desorption isotherm of solid guanidine sulfate powder in the range of 0-5Mpa at 25°C. The mass percentage of carbon dioxide in the powder after adsorption of carbon dioxide is 24%;

[0019] Figure 3 The X-ray powder diffraction patterns of the guanidine sulfate powder and the obtained carbon dioxide@guanidine sulfate sample used in the examples of the present application;

[0020] Figure 4 The thermogravimetric curve of carbon dioxide @ guanidine sulfate shows that carbon dioxide can be released by heating;

[0021] Figure 5 11.3 g of guanidine sulfate powder placed in a glass bottle at room temperature and pressure stores 2.3 g of carbon dioxide. DETAILED DESCRIPTION

[0022] To solve the shortcomings of existing carbon dioxide capture, storage and transportation technology, the inventor proposes a method for carbon dioxide capture, storage and transportation, in which carbon dioxide molecules are fixed in a lattice by suitable materials, and can be directly used for storage and transportation. In the disclosed guanidine sulfate aqueous solution carbon dioxide capture technology (patent application number 202210271224.0), carbon dioxide under a certain pressure is dissolved in an aqueous solution, and guanidine ions and sulfate ions in the solution are formed into inclusion compounds and precipitated by supramolecular interactions, and carbon dioxide is captured. Guanidine sulfate powder or crystal itself is not a porous material, and gases such as nitrogen and hydrogen cannot be effectively adsorbed.

[0023] However, surprisingly, the carbon dioxide capture, storage and transportation technology of the present invention is realized by using a solid guanidine sulfate powder as an adsorbent for carbon dioxide. The inventors used, for example, a crystalline solid guanidine sulfate powder (C2H 12 After the adsorption of carbon dioxide by N6O4S (CAS No.: 594-14-9), unexpectedly good technical effects of carbon dioxide capture, storage and transportation were obtained.

[0024] Therefore, the present disclosure provides a method for capturing, storing and transporting carbon dioxide, in which guanidine sulfate powder is used as an adsorbent to selectively absorb carbon dioxide or pure carbon dioxide in a gas mixture to obtain a carbon dioxide @ guanidine sulfate sample. The term "gas mixture" refers to a gas mixture of carbon dioxide and at least one other gas. There is no particular limitation on the mass ratio of carbon dioxide in the gas mixture. For example, the mixture may contain 1-99% (mass percentage) of carbon dioxide, and the higher the proportion of carbon dioxide, the easier it is for adsorption to occur.

[0025] In the embodiment of the present application, guanidine sulfate powder can be contacted with carbon dioxide gas of different pressures, so that carbon dioxide and guanidine sulfate form carbon dioxide @ guanidine sulfate sample, which is a kind of inclusion compound. The pressure of carbon dioxide mainly affects the rate of guanidine sulfate powder to carbon dioxide absorption, and according to the adsorption curve, adsorption of carbon dioxide can also occur when carbon dioxide is less than an atmospheric pressure. But preferably, guanidine sulfate powder contacts with carbon dioxide gas of higher pressure. For example, the pressure of carbon dioxide gas can be 0.2Mpa, 0.5Mpa, 1Mpa, 2Mpa, 3Mpa, 6Mpa etc., or it can be any pressure range such as 0.5Mpa-2Mpa formed as endpoints at these numerical values.

[0026] In an embodiment of the present application, guanidine sulfate powder can be contacted with carbon dioxide gas at different temperatures to form carbon dioxide and guanidine sulfate into carbon dioxide@guanidine sulfate sample. For example, the contact can be carried out at room temperature or at an elevated temperature.

[0027] Attached Figure 1 The low-pressure CO2 adsorption curve of guanidine sulfate powder at 25° C. Guanidine sulfate powder was heated to 100° C. and vacuum degassed for 2 h, and then placed on a gas adsorption instrument to measure the isothermal adsorption-desorption curve in the range of 0-15 bar (0-1.5 MPa) at 25° C., indicating that the adsorption amount of carbon dioxide in this pressure range can reach 17%.

[0028] Attached Figure 2 The high-pressure CO2 adsorption curve of guanidine sulfate powder at 25°C is shown. The guanidine sulfate powder was heated to 100°C and vacuum degassed for 2h, and then placed on a gas adsorption instrument to measure the isothermal adsorption-desorption curve in the range of 0-50 bar (0-5 MPa) at 25°C, indicating that the adsorption amount of carbon dioxide in this pressure range can reach 24% by mass.

[0029] Without being bound by any theory, the inventors of the present application believe that: when guanidine sulfate powder is exposed to a certain carbon dioxide pressure, carbon dioxide molecules diffuse in the lattice of solid guanidine sulfate and enter the lattice of guanidine sulfate, and are finally fixed in the lattice of guanidine sulfate to form a carbon dioxide @ guanidine sulfate sample, which is a solid powder. Unlike traditional porous physical adsorbents, guanidine sulfate solid powder itself is a non-porous material and has no adsorption to nitrogen. Since carbon dioxide molecules have a weak interaction with guanidine ions in guanidine sulfate, they can diffuse into the lattice of guanidine sulfate to form a crystalline carbon dioxide @ guanidine sulfate powder with a fixed crystal structure with a long-range order. That is, the inventors of the present application believe that: the present invention is based on the supramolecular interaction between carbon dioxide molecules and guanidine ions in guanidine sulfate. Under certain temperature and pressure conditions, carbon dioxide molecules can achieve effective adsorption, diffusion, and transmission in non-porous solids, and can achieve up to 24% (mass fraction of carbon dioxide) adsorption. This technology is completely different from the adsorption of carbon dioxide by guanidine sulfate aqueous solution in science, and is also completely different in technology. The application fields include storage, transportation, carbon dioxide energy storage, etc.

[0030] The applicant believes that the process of carbon dioxide adsorption by guanidine sulfate solid is completely different from that by aqueous solution. During the adsorption process of aqueous solution, free guanidine ions, sulfate ions and carbon dioxide molecules dissolved in water interact with each other to crystallize and precipitate. For guanidine sulfate powder, carbon dioxide molecules diffuse into the non-porous guanidine sulfate lattice, and the positions of sulfate and guanidine ions move at the same time, forming a new crystal structure containing carbon dioxide molecules, carbon dioxide@guanidine sulfate.

[0031] In the present application, the conditions for successful absorption of guanidine sulfate solid powder are presumed to be: a: having supramolecular interactions with carbon dioxide molecules, not forming chemical bonds but being able to bind carbon dioxide molecules in the crystal lattice of the adsorbent. b: there are a large number of hydrogen bonds in the crystal structure of the adsorbent, because hydrogen bonds have a certain degree of flexibility and flexibility, allowing carbon dioxide molecules to diffuse in a non-porous structure and to form a reorganized stable structure.

[0032] Under the conditions of 25°C and 0-15 bar (0-1.5 MPa) pressure of carbon dioxide gas, the volume and mass ratio of carbon dioxide in the obtained carbon dioxide@guanidine sulfate sample can reach 0.252 g·cm -3 and 17wt% (with Figure 1 ), a unit volume of carbon dioxide @ guanidine sulfate sample contains 60 times the volume of carbon dioxide gas under the same temperature and pressure conditions, and the pressure of carbon dioxide under the same temperature and volume reaches 6Mpa (compression ratio is 60), which proves the superiority of carbon dioxide storage and transportation. The adsorption curve at room temperature shows that as the pressure increases, the adsorption amount can reach 24wt% (attached Figure 2 ).

[0033] In an embodiment of the present application, the obtained carbon dioxide@guanidine sulfate sample is heated within a temperature range of 50-100° C. to release high-purity carbon dioxide. Moreover, after releasing high-purity carbon dioxide, the obtained guanidine sulfate can be directly recycled for the next round of carbon dioxide adsorption.

[0034] In the embodiments of the present application, the obtained carbon dioxide @ guanidine sulfate sample can be stored and / or transported under normal temperature and pressure conditions. Moreover, high-cost containers such as steel cylinders or cryogenic equipment are not required during transportation. For example, the carbon dioxide @ guanidine sulfate sample after capturing carbon dioxide can be stored in low-cost containers such as plastic. Without being bound by any theory, the applicant believes that this is because the guanidine sulfate powder produced after the decomposition of carbon dioxide @ guanidine sulfate on the surface of the particles is coated on the outside of the undecomposed carbon dioxide @ guanidine sulfate, preventing the internal carbon dioxide @ guanidine sulfate from further decomposing, so high-pressure resistant devices such as steel cylinders and cryogenic equipment are not required, which greatly reduces the cost of carbon dioxide storage and transportation, while improving the safety of the process.

[0035] Attached Figure 3 The powder X-ray diffraction diagram of the guanidine sulfate powder used in the present invention and the obtained carbon dioxide guanidine sulfate inclusion complex is shown. The guanidine sulfate powder is placed in an environment of 1Mpa carbon dioxide and 25°C, and after 12 hours, the guanidine sulfate is completely converted into carbon dioxide@guanidine sulfate.

[0036] Attached Figure 4 The thermogravimetric curve of the carbon dioxide guanidine sulfate inclusion complex is also shown. Carbon dioxide@guanidine sulfate is placed in a thermogravimetric analyzer, and the heating rate is set to 10°C / min. As carbon dioxide is released, the mass gradually decreases. This proves that carbon dioxide can be released by heating at a lower temperature.

[0037] Attached Figure 5 The graph shows the mass change of guanidine sulfate before and after carbon dioxide adsorption. A glass bottle containing 11.3g guanidine sulfate was placed in a 2Mpa carbon dioxide atmosphere and the temperature was set to 25°C. After standing for 24 hours, it was taken out and weighed. The mass increase was 13.6g, of which the mass percentage of carbon dioxide was 16.9%.

[0038] Compared with the existing carbon dioxide capture, storage and transportation technologies, the benefits of the present invention are: the capture process is not affected by nitrogen and water vapor, and the carbon dioxide @ guanidine sulfate powder obtained after capture can be directly used for storage and transportation; no high-cost containers such as steel cylinders or low-temperature equipment are required during transportation, and 60 times the volume of carbon dioxide gas can be stored; high-purity carbon dioxide can be released by heating at a relatively low temperature (for example, heating in the temperature range of 50-100°C), and the guanidine sulfate powder after the carbon dioxide is released can be directly used in a new cycle.

[0039] In particular, compared with the inventor's previous work (carbon dioxide capture technology using guanidine sulfate aqueous solution (patent application number 202210271224.0, the entire content of this patent application is incorporated herein by reference), the benefits are: a: the process is simpler and does not require the introduction of water. b: After the solid guanidine sulfate powder absorbs carbon dioxide to form carbon dioxide @guanidine sulfate, it does not need to be separated from water and can be directly stored or transported. c: Guanidine sulfate powder can be used in a carbon dioxide energy storage device, and excess electrical energy is compressed by a compressor to allow carbon dioxide to enter the guanidine sulfate powder lattice, converting electrical energy into chemical energy. When electricity is scarce, the carbon dioxide @guanidine sulfate powder is heated to release carbon dioxide to drive a turbine to convert chemical energy into electrical energy.

[0040] The application scenarios of the present invention include but are not limited to:

[0041] 1. Capture and purify carbon dioxide. Solid guanidine sulfate powder can selectively absorb carbon dioxide molecules and store carbon dioxide in the form of molecules in carbon dioxide @ guanidine sulfate solid powder, and the capture process is not affected by water vapor, etc. The generated carbon dioxide @ guanidine sulfate powder can be decomposed at a lower temperature to release high-purity carbon dioxide gas for use in food, electronic gas and other fields.

[0042] 2. Carbon dioxide storage and transportation. After capturing carbon dioxide, the carbon dioxide@guanidine sulfate can be stored and transported in low-cost containers such as plastic.

[0043] 3. In addition, it has potential in carbon dioxide energy storage. Compared with gaseous carbon dioxide at normal temperature and pressure, the compression ratio of carbon dioxide in carbon dioxide@guanidine sulfate powder is as high as 60, which greatly reduces the footprint of the gas storage system.

[0044] Example

[0045] The present invention is further illustrated in more detail by way of examples below.

[0046] The guanidine sulfate solid powder (C2H 12 N6O4S) from CAS No.: 594-14-9 or 1184-68-5.

[0047] Example 1

[0048] Take 3g of guanidine sulfate powder and place it in an autoclave, replace the gas in the autoclave with 1Mpa of carbon dioxide gas 3 times, then set the gas pressure in the autoclave to 1MPa, and close the autoclave valve. Let the autoclave stand for 4 hours. After opening the reactor, weigh the solid powder, the mass increase is 0.58g, the mass percentage of carbon dioxide after adsorption is 16.2%, and the conversion rate is 95.3%. The conversion rate refers to (the same below) the ratio of the amount of substance actually converted into carbon dioxide @ guanidine sulfate to the amount of substance of carbon dioxide @ guanidine sulfate that should be obtained theoretically. The obtained solid powder is placed in a glass bottle and heated at 60°C to release carbon dioxide.

[0049] Example 2

[0050] Take 3g of guanidine sulfate powder and place it in a high-pressure reactor. Replace the gas in the reactor with 0.5Mpa carbon dioxide gas 3 times, then set the gas pressure in the reactor to 0.5MPa, and close the valve of the high-pressure reactor. Let the reactor stand for 4 hours. After opening the reactor, weigh the solid powder, the mass increase is 0.46g, the mass percentage of carbon dioxide after adsorption is 13.29%, and the conversion rate is 78.2%. The obtained solid powder is placed in a glass bottle and heated at 60°C to release carbon dioxide.

[0051] Example 3

[0052] Take 3g of guanidine sulfate powder and place it in a high-pressure reactor. Replace the gas in the reactor with 0.5Mpa carbon dioxide gas 3 times, then set the gas pressure in the reactor to 0.5MPa, and keep the valve of the high-pressure reactor connected to the carbon dioxide cylinder. Let the reactor stand for 2 hours. After opening the reactor, weigh the solid powder, the mass increase is 0.54g, the mass percentage of carbon dioxide after adsorption is 15.25%, and the conversion rate is 89.7%. The obtained solid powder is placed in a glass bottle and heated at 60°C to release carbon dioxide.

[0053] Example 4

[0054] Take 3g of guanidine sulfate powder and place it in an autoclave, replace the gas in the autoclave with 2Mpa mixed gas (15% carbon dioxide, 85% nitrogen) 3 times, and then set the gas pressure in the autoclave to 2MPa. Let the autoclave stand for 4 hours. After opening the autoclave, weigh the solid powder, the mass increase is 0.52g, the mass percentage of carbon dioxide after adsorption is 14.8%, and the conversion rate is 87.1%. The obtained solid powder is placed in a glass bottle and heated at 60°C to release carbon dioxide.

[0055] Example 5

[0056] Take 3g of guanidine sulfate powder and place it in an autoclave, replace the gas in the autoclave with 2Mpa mixed gas (15% carbon dioxide, 80% nitrogen, 5wt% water vapor) 3 times, and then set the gas pressure in the autoclave to 2MPa. Let the autoclave stand for 4 hours. After opening the autoclave, weigh the solid powder, the mass increase is 0.51g, the mass percentage of carbon dioxide after adsorption is 14.5%, and the conversion rate is 85.3%. The obtained solid powder is placed in a glass bottle and heated at 60°C to release carbon dioxide.

[0057] Example 6

[0058] The solid carbon dioxide @ guanidine sulfate sample after capturing carbon dioxide was placed in a plastic bottle and the lid was tightened. The solid mass in the bottle was 27.8g, containing 4.70g of carbon dioxide, with a mass percentage of 16.9%. After being placed at room temperature for three days, the solid mass in the bottle was 27.6g, and the mass percentage of carbon dioxide was 16.3%. After being placed at room temperature for 10 days, the solid mass in the bottle was 27.5g, and the mass percentage of carbon dioxide was 16.0%. After being placed at room temperature for 30 days, the solid mass in the bottle was still 27.5g, and the mass percentage of carbon dioxide was 16.0%. The powder was heated to 50°C, and the carbon dioxide was completely released.

[0059] Example 6 proves that the carbon dioxide @ guanidine sulfate sample has application potential in the transportation and storage of carbon dioxide, because it can be stored in a normal temperature differential pressure and ordinary container, wherein the amount of carbon dioxide remains substantially unchanged. Example 6 also illustrates that the carbon dioxide @ guanidine sulfate sample obtained by the present invention is stored in a plastic container or a glass container at room temperature for at least 30 days without or almost without carbon dioxide desorption.

[0060] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

[0061] Industrial Applicability

[0062] The present invention uses guanidine sulfate powder to achieve high-efficiency and low-energy capture of carbon dioxide, and the obtained carbon dioxide@guanidine sulfate inclusion compound can achieve storage and transportation of carbon dioxide at normal temperature and pressure, and the carbon dioxide separated by the method of the present invention has extremely high purity, and theoretically the purity of carbon dioxide can reach 100%. Therefore, the present invention will have good industrial application prospects.

Claims

1. A method for capturing, storing and transporting carbon dioxide, the method comprising: Guanidine sulfate powder is used to selectively absorb carbon dioxide in a gas mixture or pure carbon dioxide to obtain a carbon dioxide@guanidine sulfate sample.

2. The method of claim 1, wherein the selective absorption comprises contacting the guanidine sulfate powder with carbon dioxide gas at different pressures.

3. The method according to claim 2, wherein the time required for the contacting depends on the carbon dioxide pressure, and the higher the pressure, the shorter the contacting time required.

4. The method according to claim 2, wherein the time required for the contacting also depends on the ambient temperature during the contacting. The method of claim 2 , wherein the contacting is performed at room temperature.

6. The method according to claim 1, wherein the method further comprises: Heating the carbon dioxide@guanidine sulfate sample within a temperature range of 50-100° C. releases high purity carbon dioxide.

7. The method according to claim 6, wherein the method further comprises: The obtained guanidine sulfate was directly recycled for the next round of carbon dioxide adsorption.

8. The method according to claim 1, wherein the method comprises: The carbon dioxide@guanidine sulfate sample is stored and / or transported under normal temperature and pressure conditions.

9. The method according to claim 8, wherein the carbon dioxide@guanidine sulfate sample is stored in a plastic container or a glass container at room temperature for at least 30 days without carbon dioxide desorption.

10. The method according to claim 1, wherein the guanidine sulfate powder has a crystal structure parameter of: a=b=c=17.7640, α=β=γ=90°, a chemical formula of: [C(NH2)3]2SO4, and a CAS number of: 594-14-9.

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