Ammonia adsorbent and manufacturing method therefor

Abstract

An ammonia adsorbent according to an embodiment of the present invention may comprise a carbon molecular sieve (CMS) having, supported thereon, MgCl2 and CaCl2.

Description

Ammonia adsorbent and method for manufacturing the same

[0001] The present invention relates to an ammonia adsorbent and a method for manufacturing the same.

[0002] Conventional ammonia removal processes have been primarily used for ammonia recovery processes to improve the performance of the Haber-Bosch process and for ammonia removal processes to prevent emissions into the atmosphere.

[0003] The hydrogen production process using ammonia is a process in which ammonia is decomposed into nitrogen and hydrogen by a catalyst under high temperature conditions as shown in reaction equation 1 below, and depending on the decomposition rate, undecomposed ammonia is contained in the decomposition gas (N2, H2), and high-purity hydrogen is produced through a process to remove it.

[0004] [Reaction Equation 1]

[0005] 2NH3→ N2+ 3H2

[0006] To this end, undecomposed ammonia was removed by an adsorption process that adsorbs ammonia using an adsorbent for ammonia adsorption in adsorption processes such as PSA, TSA, and VPSA.

[0007] To this end, conventional studies have used various adsorbents to remove ammonia, and examples include studies that primarily used zeolite, alumina, silica gel, and activated carbon.

[0008] However, conventional adsorbents had a problem where their ammonia adsorption performance deteriorated during repeated regeneration processes.

[0009] Therefore, there is a need for an adsorbent that maintains excellent ammonia adsorption performance even after long-term use.

[0010] One embodiment of the present invention can provide an ammonia adsorbent that maintains stable performance without performance degradation by improving long-term stability, and a method for manufacturing the same.

[0011] One embodiment of the present invention can provide an ammonia adsorbent with excellent ammonia adsorption capacity and a method for manufacturing the same.

[0012] The problems of the present invention are not limited to those described above. A person skilled in the art to which the present invention pertains will have no difficulty understanding additional problems of the present invention from the overall contents of this specification.

[0013] An ammonia adsorbent, which is an embodiment of the present invention, may include a Carbon Molecular Sieve (CMS) supported with MgCl2 and CaCl2.

[0014] The above MgCl2 may be included in an amount of 0.1 to 5 weight percent based on the total weight of the adsorbent.

[0015] The above CaCl2 may be included in an amount of 0.1 to 3 weight percent based on the total weight of the adsorbent.

[0016] The above adsorbent may additionally support a metal halide.

[0017] The metal halide may be at least one selected from the group consisting of SrCl2, MgBr2, CaBr2, and SrBr2.

[0018] A method for manufacturing an ammonia adsorbent, which is an embodiment of the present invention, may include the steps of: preparing a Carbon Molecular Sieve (CMS); immersing the CMS in an MgCl2 solution to support MgCl2 on the interface of the CMS; and immersing the CMS supported with MgCl2 in a CaCl2 solution to support CaCl2 on the interface of the CMS.

[0019] The weight of MgCl2 relative to the total weight of the above MgCl2 solution may be included in an amount of 0.1 to 5 weight%.

[0020] The weight of CaCl2 relative to the total weight of the above CaCl2 solution may be included in an amount of 0.1 to 3 weight%.

[0021] The method may further include a step of additionally supporting the CMS loaded with MgCl2 and CaCl2 on a metal halide to load the metal halide.

[0022] The metal halide may be at least one selected from the group consisting of SrCl2, MgBr2, CaBr2, and SrBr2.

[0023] The ammonia adsorbent and the method for manufacturing the same, which is an embodiment of the present invention, have improved long-term stability and can maintain stable performance without performance degradation.

[0024] An ammonia adsorbent and a method for manufacturing the same, which is an embodiment of the present invention, may have excellent ammonia adsorption capacity.

[0025] FIG. 1 is a conceptual diagram exemplarily showing an adsorbent of the present invention being supported on the interface of CMS.

[0026] FIG. 2 is a conceptual diagram exemplarily showing that the adsorbent of the comparative example of the present invention is supported on the interface of CMS.

[0027] Figure 3 is a graph showing the breakthrough time of NH3 adsorption for each PSA cycle between comparative example adsorbents.

[0028] Preferred embodiments of the present invention will be described below with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0029] In addition, embodiments of the present invention are provided to more fully explain the present invention to those with average knowledge in the relevant technical field.

[0030] In drawings, the shapes and sizes of elements may be exaggerated for clearer explanation.

[0031] In describing the embodiments of the present invention, if it is determined that a detailed description of known technology related to the present invention may unnecessarily obscure the essence of the present invention, such detailed description will be omitted. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intentions or conventions of the user or operator. Therefore, such definitions should be based on the content throughout this specification. The terms used in the detailed description are merely for describing the embodiments of the present invention and should not be limited in any way. Unless explicitly stated otherwise, expressions in the singular form include the meaning of the plural form.

[0032] In this description, expressions such as “include” or “equipped” are intended to refer to certain characteristics, numbers, steps, actions, elements, parts or combinations thereof, and should not be interpreted to exclude the existence or possibility of one or more other characteristics, numbers, steps, actions, elements, parts or combinations thereof other than those described.

[0033] Unless otherwise specifically defined in the specification of the present invention, % units mean weight %.

[0034] In this specification, terms such as 'top', 'upper', 'upper surface', 'lower', 'lower surface', 'lower surface', and 'side surface' are based on the drawings and may actually vary depending on the direction in which the elements or components are arranged.

[0035] Additionally, throughout the specification, when it is said that one part is 'connected' to another part, this includes not only cases where they are 'directly connected,' but also cases where they are 'indirectly connected' with other elements in between.

[0036] The present invention will be described in detail below through each embodiment or example of the invention. It should be noted that each embodiment or example described in this specification is not limited to a single embodiment or example, but may also be combined with other embodiments or examples. Accordingly, the citation of claims in the patent claims is merely an example of an embodiment, and the technical concept of the present invention should not be interpreted as being limited only to a combination with the cited claims; rather, combinations with various claims are also included within the scope of the technical concept of the present invention.

[0037] One embodiment of the present invention can provide an ammonia adsorbent with excellent ammonia adsorption capacity and improved long-term stability, maintaining stable performance without performance degradation, and a method for manufacturing the same.

[0038] Carbon Molecular Sieve (CMS) is primarily manufactured by the thermal decomposition of polymers or coal-based materials; it possesses a high surface area and durability, and has nanometer-sized pores that allow it to adsorb ammonia.

[0039] While CMS is generally known for its high durability, a problem may arise where the breakthrough time gradually shortens with long-term use. Additionally, there is an issue in that CMS itself does not have high ammonia adsorption performance.

[0040] Accordingly, by supporting metal halides on CMS, the ammonia adsorption performance and long-term use performance of CMS can be improved.

[0041] Accordingly, an ammonia adsorbent of one embodiment of the present invention may include a CMS supported with magnesium chloride (hereinafter MgCl2) and calcium chloride (hereinafter CaCl2).

[0042] FIG. 1 is a conceptual diagram exemplifying the adsorbent of an embodiment of the present invention being supported on the interface of CMS, and the embodiment may be an adsorbent in which MgCl2 and CaCl2 are supported on the interface of CMS. FIG. 2 is a conceptual diagram exemplifying the adsorbent of a comparative example of the present invention being supported on the interface of CMS, and the embodiment may be an adsorbent in which only MgCl2 is supported on the interface of CMS. When MgCl2 and CaCl2 are supported on the interface of CMS, CaCl2 strengthens the bond between the CMS interface and MgCl2, thereby maintaining long-term stability without performance degradation of the adsorbent even during repeated adsorption-regeneration cycles. On the other hand, if CaCl2 is not supported, the bond energy between the interface of CMS and MgCl2 decreases, and the breakthrough time may become progressively shorter when used for a long period.

[0043] The above MgCl2 may be included in an amount of 0.1 to 5 weight% relative to the total weight of the adsorbent, specifically 0.1 to 3 weight%, and more specifically 0.8 to 1.2 weight%. If the weight of MgCl2 relative to the total weight of the adsorbent is less than 0.1 weight%, the ammonia adsorption performance may be reduced, and the reaction rate and efficiency may decrease due to a lack of catalyst active sites. If the weight of MgCl2 exceeds 5 weight%, the adsorption capacity and efficiency may decrease because ammonia cannot permeate into the CMS due to the formation of coarse MgCl2 particles in the pores, and some of the MgCl2 remains on the surface in an inactive state, reducing the effective adsorption area and causing collapse or damage to the CMS.

[0044] The above CaCl2 may be included in an amount of 0.1 to 3 weight% relative to the total weight of the adsorbent, specifically 0.3 to 1 weight%. If the weight of CaCl2 relative to the total weight of the adsorbent is less than 0.1 weight%, the ammonia adsorption performance may be reduced, and the reaction rate and efficiency may decrease due to a lack of catalytic active sites, and stability may decrease because the binding energy between CMS and MgCl2 cannot be effectively controlled. If the weight of CaCl2 exceeds 3 weight%, CaCl2 particles may grow, reducing the adsorption sites formed from MgCl2 and lowering the ammonia adsorption performance. Furthermore, due to the formation of coarse CaCl2 particles in the pores, ammonia may not be able to permeate into the CMS, resulting in a decrease in adsorption capacity and efficiency. Additionally, some of the CaCl2 may remain on the surface in an inactive state, reducing the effective adsorption area and potentially causing the collapse or damage of the CMS.

[0045] In addition, the ammonia adsorbent of one embodiment of the present invention may additionally support a metal halide. The metal halide may be at least one selected from the group consisting of SrCl2, MgBr2, CaBr2, and SrBr2.

[0046] The ammonia adsorbent of one embodiment of the present invention can be used in processes such as pressure swing adsorption (PSA), temperature swing adsorption (TSA), and vacuum swing adsorption (VPSA), and can possess not only ammonia adsorption capacity but also long-term stability.

[0047] Hereinafter, a method for manufacturing an ammonia adsorbent, which is an embodiment of the present invention, will be described.

[0048] A method for manufacturing an ammonia adsorbent, which is an embodiment of the present invention, may include the steps of: preparing a Carbon Molecular Sieve (CMS); immersing the CMS in an MgCl2 solution to support MgCl2 on the interface of the CMS; and immersing the CMS supported with MgCl2 in a CaCl2 solution to support CaCl2 on the interface of the CMS.

[0049] The weight of MgCl2 relative to the total weight of the above MgCl2 solution may be included in an amount of 0.01 to 5 weight%, specifically 0.1 to 3 weight%, and more specifically 0.8 to 1.2 weight%.

[0050] The weight of CaCl2 relative to the total weight of the above CaCl2 solution may be included in an amount of 0.01 to 5 weight%, specifically 0.1 to 3 weight%, and more specifically 0.3 to 1 weight%.

[0051] A method for manufacturing an ammonia adsorbent, which is an embodiment of the present invention, may further include the step of additionally supporting a CMS loaded with MgCl2 and CaCl2 on a metal halide to load the metal halide. The metal halide may be at least one selected from the group consisting of SrCl2, MgBr2, CaBr2, and SrBr2.

[0052] The ammonia adsorbent produced by the method for producing an ammonia adsorbent according to one embodiment of the present invention can be used in processes such as pressure swing adsorption (PSA), temperature swing adsorption (TSA), and vacuum swing adsorption (VPSA), and can possess not only ammonia adsorption capacity but also long-term stability.

[0053] Examples

[0054] The present invention will be described in detail below through examples. However, it should be noted that the examples described below are intended merely to illustrate and embody the present invention and are not intended to limit the scope of the present invention. This is because the scope of the present invention is determined by the matters described in the patent claims and matters reasonably inferred therefrom.

[0055] Preparation Example

[0056] 1. Comparative Example 1

[0057] A CMS adsorbent was prepared by washing and drying the CMS at 100°C to remove impurities and then drying it completely in an oven, and this is designated as Comparative Example 1.

[0058] 2. Comparative Example 2

[0059] After dissolving MgCl2 in distilled water in a flask at a concentration of 1 wt%, the adsorbent of Comparative Example 1 was added to the same flask. Subsequently, distilled water was evaporated for 10 hours in a rotary evaporator at 50°C and 50 rpm to ensure that MgCl2 was evenly deposited on the surface of the CMS. Then, the MgCl2 / CMS adsorbent was prepared by drying in a drying oven at 100°C for 10 hours to remove moisture and stabilize the bonding, and this was designated as Comparative Example 2.

[0060] The weight of MgCl2 relative to the total weight of the manufactured MgCl2 / CMS adsorbent is 1 wt%.

[0061] 3. Example 1

[0062] 0.5 wt% CaCl2 was dissolved in distilled water and loaded onto the adsorbent of Comparative Example 2. Subsequently, the adsorbent was treated under the same conditions in a rotary evaporator at 50°C and 50 rpm, and then dried and heat-treated in an oven at 100°C for 10 hours to ensure that the CaCl2 was stably bound to the surface of the CMS.

[0063] The weights of MgCl2 and CaCl2 relative to the total weight of the prepared MgCl2-CaCl2 / CMS adsorbent are 1 wt% and 0.5 wt%, respectively.

[0064] Experimental Example

[0065] 1. Measurement of breakthrough time

[0066] Adsorbents for Comparative Examples 1 and 2 were prepared under different drying and wetting conditions, and the prepared adsorbents were loaded into a PSA ammonia adsorber.

[0067] Subsequently, the ammonia adsorption breakthrough time per cycle was measured when a gas containing 11.1 mol% ammonia, 22.2 mol% nitrogen, and 66.7 mol% hydrogen was introduced into the ammonia adsorber at a pressure of 7 bar at a flow rate of 4 LPM (L / min), and this is shown in Figure 3.

[0068] Referring to Fig. 3, it can be seen that the ammonia adsorption performance of Comparative Example 2, which supports MgCl2, is higher than that of Comparative Example 1, but the breakthrough time becomes shorter as the cycle progresses.

[0069] 2. Measurement of binding energy

[0070] The binding energy between the CMS and metal halide of the adsorbents of Example 1 and Comparative Example 2 was measured using X-ray photoelectron spectroscopy (XPS, Thermo Scientific), and is shown in Table 1.

[0071] Binding Energy (eV) Example 12.45 Comparative Example 22.20

[0072] Referring to Table 1 above, it can be confirmed that the binding energy of the adsorbent in Example 1 is higher than that of the adsorbent in Comparative Example 2. This may mean that if CaCl2 is additionally supported on MgCl2, MgCl2 is more strongly supported on the CMS surface, and it can be predicted that the breakthrough time of the adsorbent in Example 1 will be maintained longer than the breakthrough time of the adsorbent in Comparative Example 2.

Claims

1. An ammonia adsorbent comprising a Carbon Molecular Sieve (CMS) supported with MgCl2 and CaCl2.

2. In Paragraph 1, The above MgCl2 is an ammonia adsorbent in an amount of 0.1 to 5 weight percent based on the total weight of the adsorbent.

3. In Paragraph 1, The above CaCl2 is an ammonia adsorbent in an amount of 0.1 to 3 weight percent based on the total weight of the adsorbent.

4. In Paragraph 1, The above adsorbent is an ammonia adsorbent additionally supported with a metal halide.

5. In Paragraph 1, The above metal halide is at least one selected from the group consisting of SrCl2, MgBr2, CaBr2 and SrBr2, an ammonia adsorbent.

6. Step to prepare the CMS (Carbon Molecular Sieve); A step of immersing the above CMS in an MgCl2 solution to support MgCl2 on the interface of the above CMS; and A method for manufacturing an ammonia adsorbent comprising the step of immersing a CMS loaded with MgCl2 in a CaCl2 solution to load CaCl2 onto the interface of the CMS.

7. In Paragraph 6, A method for manufacturing an ammonia adsorbent, wherein the weight of MgCl2 relative to the total weight of the above MgCl2 solution is 0.1 to 5 weight%.

8. In Paragraph 6, A method for manufacturing an ammonia adsorbent, wherein the weight of CaCl2 relative to the total weight of the above CaCl2 solution is 0.1 to 3 weight%.

9. In Paragraph 6, A method for manufacturing an ammonia adsorbent, further comprising the step of additionally supporting a CMS loaded with MgCl2 and CaCl2 onto a metal halide to support the metal halide.

10. In Paragraph 6, A method for manufacturing an ammonia adsorbent, wherein the metal halide is at least one selected from the group consisting of SrCl2, MgBr2, CaBr2 and SrBr2.

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