Ammonia adsorbent comprising magnesium silicate and method for producing same

Abstract

The present invention relates to an ammonia adsorbent comprising magnesium silicate and a method for producing same and, more particularly, to an ammonia adsorbent comprising magnesium silicate that has been subjected to acid treatment following heat treatment, and to a method for producing same. The magnesium silicate for ammonia adsorption according to the present invention can replace adsorbent materials composed of precious metals and metal oxides, thereby providing an adsorbent material for reducing ammonia and nitrogen oxides with low dependence on foreign sources in ammonia co-combustion and full combustion processes.

Description

Ammonia adsorbent containing magnesium silicate and method for producing the same

[0001] The present invention relates to an ammonia adsorbent comprising magnesium silicate and a method for producing the same, and more particularly, to an ammonia adsorbent comprising magnesium silicate treated with acid after heat treatment and a method for producing the same.

[0002] South Korea has driven its economic and industrial development by using fossil fuels, such as coal and oil, in hydrocarbons. However, to reduce its dependence on fossil fuel imports, the country has steadily pursued policies to develop, distribute, and expand new and renewable energy sources. Consequently, numerous studies are underway to achieve carbon neutrality.

[0003] In particular, a method of co-firing ammonia with fossil fuels has been proposed to gradually phase out coal-fired power plants. However, this method suffers from the problem of low reactivity compared to fossil fuels and the formation of NOx (nitrogen oxides) during normal combustion. These NOx emit a pungent odor even at concentrations as low as 5 ppm, leading to exposure to the atmosphere.

[0004] In addition, various technologies such as absorption, adsorption, condensation, and catalytic combustion are being developed to remove gaseous ammonia contained in exhaust gas, and a representative technology among them is the Selective Catalytic Oxidation (SCO) method. However, in order to utilize the above-mentioned selective catalytic oxidation method, precious metals such as Ag, Pt, Ru, Rh, and Pd, or metal oxides such as Cu, Fe, Ce, and Mn are used as catalysts. However, the problem is that these precious metals and metal oxides are not suitable for the reality of South Korea, which has a lack of mineral resources, and therefore, there is a high dependence on foreign countries.

[0005] Therefore, in the present invention, an adsorbent material for reducing ammonia and nitrogen oxides that is not highly dependent on foreign countries in the ammonia co-combustion and pre-combustion processes was developed.

[0006] The purpose of the present invention is to provide a magnesium silicate for ammonia adsorption that can replace adsorption materials made of precious metals and metal oxides.

[0007] Another object of the present invention is to provide a method for producing magnesium silicate for ammonia adsorption that can replace adsorption materials made of precious metals and metal oxides.

[0008] The technical problems to be solved by the invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the art from the description of the present invention.

[0009] The present invention provides an ammonia adsorbent comprising magnesium silicate that has been acid-treated after heat treatment, wherein the acid treatment is characterized by reacting the heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution.

[0010] In the present invention, the magnesium silicate treated with acid after the heat treatment is characterized in that the oxygen content is 50 to 56 wt%, the magnesium content is 9 to 11 wt%, and the silicon content is 33 to 39 wt%.

[0011] In the present invention, the acid-treated magnesium silicate after the heat treatment has a specific surface area of ​​400 to 500 m 2 / g, and is characterized by an average particle size of 30 to 50 μm.

[0012] In addition, the present invention provides a method for producing an ammonia adsorbent comprising magnesium silicate, comprising the steps of: a) producing magnesium silicate; b) heat-treating the produced magnesium silicate; c) reacting the heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution to produce acid-treated magnesium silicate; d) mixing the acid-treated magnesium silicate, an organic binder, and an inorganic binder to produce a mixture; and e) drying the mixture.

[0013] In the present invention, the step c) is characterized by reacting the heat-treated magnesium silicate by mixing it in a 0.1 to 0.5 M hydrochloric acid (HCl) solution or a 0.5 to 1.0 M sulfuric acid (H2SO4) solution at 1 to 3% (w / v).

[0014] The present invention can provide a magnesium silicate for ammonia adsorption that can replace adsorption materials made of precious metals and metal oxides.

[0015] In addition, the present invention can provide a method for producing the magnesium silicate for ammonia adsorption.

[0016] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0017] Figure 1 is a drawing showing the results of observing magnesium silicate acid-treated with HCl or H2SO4 using a SEM microscope.

[0018] Figure 2 is a graph showing the ammonia adsorption amount of magnesium silicate that has not been acid treated.

[0019] Figure 3 is a graph showing the ammonia adsorption amount of magnesium silicate treated with HCl.

[0020] Figure 4 is a graph showing the ammonia adsorption amount of magnesium silicate treated with H2SO4.

[0021] The terms used in this specification have been selected from widely used, current terms, taking into account the functions of the present invention. However, these terms may vary depending on the intentions of those skilled in the art, precedents, the emergence of new technologies, etc. Furthermore, in certain cases, terms may be arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should not be defined simply as names, but rather based on their inherent meanings and the overall content of the present invention.

[0022] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0023] Numerical ranges are inclusive of the numbers defined in the ranges above. Every maximum numerical limitation given throughout this specification includes every lower numerical limitation, as if that lower numerical limitation were explicitly stated. Every minimum numerical limitation given throughout this specification includes every higher numerical limitation, as if that higher numerical limitation were explicitly stated. Every numerical limitation given throughout this specification will include every better numerical range within that broader numerical range, as if that narrower numerical limitation were explicitly stated.

[0024]

[0025] Hereinafter, the present invention will be described in detail.

[0026]

[0027] Method for producing an ammonia adsorbent containing magnesium silicate

[0028] The present invention can provide a method for producing an ammonia adsorbent comprising magnesium silicate. The method can include the following steps a) to e).

[0029] a) a step of manufacturing magnesium silicate;

[0030] b) A step of heat treating the manufactured magnesium silicate;

[0031] c) a step of producing acid-treated magnesium silicate by reacting the heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution;

[0032] d) a step of preparing a mixture by mixing the above acid-treated magnesium silicate, organic binder and inorganic binder; and

[0033] e) drying the mixture;

[0034]

[0035] The step a) above may include a step a1) of preparing a reactant by reacting a magnesium salt and sodium silicate (Na2SiO3); and a2) of drying the reactant. In the step a1), the magnesium salt may be at least one selected from the group consisting of magnesium sulfate (MgSO4), magnesium chloride (MgCl2), and magnesium oxide (MgO), and preferably may be magnesium sulfate.

[0036] In addition, the above step a1) may be a step of preparing a reactant by mixing 10 to 14 parts by weight of sodium silicate with 30 parts by weight of magnesium sulfate and reacting at 20 to 40°C for 1 to 3 hours, and preferably, it may be a step of preparing a reactant by mixing 12 parts by weight of sodium silicate with 30 parts by weight of magnesium sulfate and reacting at 30°C for 2 hours.

[0037] In the step a2), the drying method may include air drying, freeze drying, hot air drying, reduced pressure drying, vacuum drying, boiling drying or spray drying, and preferably air drying may be used. More specifically, in the step a2), the reactant is dried at an inlet temperature of 230 to 250°C, an outlet temperature of 100 to 120°C, and an air volume of 800 to 1,000 m 3 / h conditions, and preferably, the reactant is dried in an air dryer having an inlet temperature of 240°C, an outlet temperature of 110°C, and an air volume of 900 m 3 It can be characterized by being dried in an air dryer having conditions of / h.

[0038]

[0039] The step b) above may refer to a step of heat-treating the magnesium silicate manufactured in the step a), and more specifically, the magnesium silicate manufactured in the step a) may be heat-treated at 500 to 600°C for 2 to 4 hours at a heating rate of 4 to 6°C / min, preferably, the magnesium silicate manufactured in the step a) may be heat-treated at 540 to 560°C for 2.5 to 3.5 hours at a heating rate of 4.5 to 5.5°C / min, and even more preferably, the magnesium silicate manufactured in the step a) may be heat-treated at 550°C for 3 hours at a heating rate of 5°C / min.

[0040]

[0041] The above step c) may refer to a step of producing acid-treated magnesium silicate by reacting the magnesium silicate heat-treated in the above step b) with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution. In the above step c), the hydrochloric acid solution may have a concentration of 0.1 to 0.5 M, and preferably, the concentration may be 0.1 M. The sulfuric acid solution may have a concentration of 0.5 to 1.0 M, and preferably, the concentration may be 1.0 M.

[0042] The above step c) may be characterized by reacting the heat-treated magnesium silicate by mixing it in a hydrochloric acid solution or a sulfuric acid solution at 1 to 10% (w / v), preferably by reacting the heat-treated magnesium silicate by mixing it in a hydrochloric acid solution or a sulfuric acid solution at 1 to 3% (w / v), and more preferably by reacting the heat-treated magnesium silicate by mixing it in a hydrochloric acid solution or a sulfuric acid solution at 2% (w / v).

[0043] In addition, in the step c), the reaction temperature when reacting the heat-treated magnesium silicate with the hydrochloric acid solution may be 15 to 25°C, and the reaction time may be 10 minutes to 1 hour. Preferably, the reaction temperature when reacting the heat-treated magnesium silicate with the hydrochloric acid solution may be 20°C, and the reaction time may be 1 hour.

[0044] In addition, in the step c), the reaction temperature when reacting the heat-treated magnesium silicate with the sulfuric acid solution may be 70 to 90°C, and the reaction time may be 1 to 2 hours. Preferably, the reaction temperature when reacting the heat-treated magnesium silicate with the sulfuric acid solution may be 80°C, and the reaction time may be 2 hours.

[0045] Additionally, in the step c), the stirring speed when reacting the hydrochloric acid or sulfuric acid solution with the heat-treated magnesium silicate may be 300 to 400 rpm.

[0046]

[0047] The above step d) may refer to a step of coating the acid-treated magnesium silicate with a binder. More specifically, the above step d) may include the steps d1) preparing a mixture by mixing the acid-treated magnesium silicate, an organic binder, and an inorganic binder; and d2) filtering and washing the mixture.

[0048] In the above step d1), the organic binder may be at least one selected from the group consisting of methyl cellulose, glycerin, corn oil, and Dispersion-5468CF, and preferably, methyl cellulose, glycerin, corn oil, and Dispersion-5468CF may be used in combination.

[0049] In the above step d1), the inorganic binder may be at least one selected from the group consisting of colloidal silica, sodium hydroxide, potassium hydroxide, 1,1´-Oxybisbenzene, tetrapropylene, isooctyl alcohol, and water, and preferably, colloidal silica, sodium hydroxide, potassium hydroxide, 1,1´-Oxybisbenzene, tetrapropylene, isooctyl alcohol, and water may be used in mixture.

[0050] In the above step d2), the filtration method may include atmospheric pressure filtration, reduced pressure filtration, pressurized filtration, filter paper, filter cloth, mesh net, filter or centrifugation, and preferably reduced pressure filtration may be used.

[0051] In the above step d2), the washing may be characterized by washing so that the pH of the filtered mixture becomes 6 to 7.

[0052]

[0053] In the above step e), freeze drying, hot air drying, reduced pressure drying, vacuum drying, boiling drying or spray drying may be used as the drying method, and preferably hot air drying may be used, and more preferably, hot air drying may be performed at 60 to 80°C for 10 to 14 hours.

[0054]

[0055] In addition, the present invention can provide an ammonia adsorbent comprising magnesium silicate, manufactured according to the manufacturing method described above.

[0056]

[0057] Ammonia adsorbent containing magnesium silicate

[0058] The present invention can provide an ammonia adsorbent comprising magnesium silicate, wherein the magnesium silicate is characterized by being acid-treated after heat treatment. The acid treatment can be characterized by reacting the heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution.

[0059] According to one embodiment of the present invention, the acid-treated magnesium silicate after the heat treatment may be characterized by an oxygen content of 50 to 56 wt%, a magnesium content of 9 to 11 wt%, and a silicon content of 33 to 39 wt%, preferably characterized by an oxygen content of 53 to 55 wt%, a magnesium content of 10.5 to 11 wt%, and a silicon content of 34 to 36 wt%, and more preferably characterized by an oxygen content of 54.06 wt%, a magnesium content of 10.83 wt%, and a silicon content of 35.56 wt%.

[0060] According to one embodiment of the present invention, the acid-treated magnesium silicate after the heat treatment has a specific surface area of ​​400 to 500 m 2 / g, and may be characterized by an average particle size of 30 to 50 μm, and preferably a specific surface area of ​​450 to 500 m 2 / g, and may be characterized by an average particle size of 45 to 50 μm, more preferably 490 to 495 m 2 / g, and can be characterized by an average particle size of 48 to 49 μm.

[0061] According to one embodiment of the present invention, the ammonia adsorption amount of the acid-treated magnesium silicate after the heat treatment may be 1.0 to 2.0 mmol / g, preferably 1.5 to 1.6 mmol / g, and more preferably 1.53 mmol / g.

[0062] Hereinafter, examples of the present invention will be described in detail, but it is obvious that the present invention is not limited to the following examples.

[0063]

[0064] Example 1. Preparation of magnesium silicate for ammonia adsorption treated with hydrochloric acid

[0065]

[0066] 1-1. Manufacturing of magnesium silicate

[0067] 30 kg of magnesium sulfate (MgSO4), 12 kg of sodium silicate (Na2SiO3), and 60 L of water were added to the reactor and reacted for 2 hours with stirring at 30°C. Then, the cake obtained by filtering with a concave plate filter press was dried in an air dryer to produce magnesium silicate. The air dryer had an inlet temperature of 240°C, an outlet temperature of 110°C, and an air flow of 900 m 3 It worked under the condition of / h.

[0068]

[0069] 1-2. Preparation of hydrochloric acid-treated magnesium silicate

[0070] The magnesium silicate prepared in Example 1-1 was heat-treated in an electric furnace at 550°C for 3 hours at a heating rate of 5°C / min. Next, the heat-treated magnesium silicate was mixed in a 0.1 M HCl solution at 2% (w / v) and reacted at room temperature for 1 hour to prepare a hydrochloric acid-treated magnesium silicate. At this time, the reaction was carried out while stirring at a speed of 300 to 400 rpm.

[0071]

[0072] 1-3. Preparation of magnesium silicate for ammonia adsorption by coating with binder

[0073] A mixture was prepared by mixing the acid-treated magnesium silicate, organic binder, inorganic binder, and water prepared in Example 1-2. The organic binder was prepared by mixing equal amounts of methyl cellulose, glycerin, corn oil, and Dispersion-5468CF, and the inorganic binder was prepared by mixing equal amounts of colloidal silicic acid, sodium hydroxide, potassium hydroxide, 1,1´-Oxybisbenzene, tetrapropylene, isooctyl alcohol, and water.

[0074] After filtering the above mixture under reduced pressure, washing was performed so that the pH became 6 to 7. The washed magnesium silicate was dried using a hot air dryer at 70°C for 12 hours, thereby producing ammonia adsorption magnesium silicate treated with hydrochloric acid.

[0075]

[0076] Example 2. Preparation of magnesium silicate for ammonia adsorption treated with sulfuric acid

[0077] Magnesium silicate was prepared in the same manner as in Example 1-1, and the magnesium silicate prepared in the same manner as in Example 1-1 was heat-treated in the same manner as in Example 1-2. Next, the heat-treated magnesium silicate was mixed in a 1.0 M H2SO4 solution at 2% (w / v) and reacted at 80°C for 2 hours to prepare magnesium silicate treated with sulfuric acid. At this time, the stirring speed was 300 to 400 rpm. Finally, magnesium silicate for ammonia adsorption was prepared by coating with a binder in the same manner as in Example 1-3 and acid-treating with sulfuric acid.

[0078]

[0079] Comparative Example 1. Preparation of magnesium silicate without acid treatment

[0080] Magnesium silicate was manufactured in the same manner as in Example 1-1, and the magnesium silicate manufactured in the same manner as in Example 1-1 was subjected to heat treatment in the same manner as in Example 1-2. Next, magnesium silicate was manufactured by coating with a binder in the same manner as in Example 1-3 without performing acid treatment.

[0081]

[0082] Experimental Example 1. SEM Microscopic Observation of Acid-Treated Magnesium Silicate

[0083] The magnesium silicate treated with HCl prepared in Example 1 and the magnesium silicate treated with H2SO4 prepared in Example 2 were observed using a SEM microscope, and the results are shown in Fig. 1.

[0084] Referring to Fig. 1, it was confirmed that the magnesium silicate manufactured in Examples 1 and 2 did not show any significant change in shape of the spherical magnesium silicate due to acid treatment.

[0085]

[0086] Experimental Example 2. SEM-EDS Analysis of Acid-Treated Magnesium Silicate

[0087] SEM-EDS analysis was performed on the magnesium silicate treated with HCl prepared in Example 1, the magnesium silicate treated with H2SO4 prepared in Example 2, and the magnesium silicate not treated with acid prepared in Comparative Example 1. The SEM-EDS analysis was performed according to ASTM D1933-03, and the results are shown in Table 1.

[0088]

[0089] Oxygen content (wt%)Magnesium content (wt%)Silicon content (wt%)Comparative example 48.298.6726.84Example 152.0910.3937.52Example 254.0610.8335.56

[0090]

[0091] Referring to Table 1, the oxygen, magnesium and silicon contents of the non-acid-treated magnesium silicate manufactured in the comparative example were 48.29, 8.67 and 26.84 wt%, respectively. On the other hand, the oxygen, magnesium and silicon contents of the HCl-acid-treated magnesium silicate manufactured in Example 1 were 52.09, 10.39 and 37.52 wt%, respectively, and the oxygen, magnesium and silicon contents of the H2SO4-acid-treated magnesium silicate manufactured in Example 2 were 54.06, 10.83 and 35.56 wt%, respectively.

[0092]

[0093] Experimental Example 3. Average particle size analysis of acid-treated magnesium silicate

[0094] The average particle sizes of the HCl-treated magnesium silicate prepared in Example 1, the H2SO4-treated magnesium silicate prepared in Example 2, and the non-acid-treated magnesium silicate prepared in Comparative Example 1 were analyzed using a particle size analyzer (Particle Size Analysis, PSA). The particle size analysis was performed based on KS A ISO 13320:2020, and the results are shown in Table 2.

[0095]

[0096] Average particle size (㎛) Comparative example 7.0 Example 131.5 Example 248.2

[0097]

[0098] Referring to Table 2, the average particle size of the non-acid-treated magnesium silicate manufactured in the comparative example was 7.0 μm. On the other hand, the average particle size of the HCl-acid-treated magnesium silicate manufactured in the example 1 was 31.5 μm, and the H2SO4-acid-treated magnesium silicate manufactured in the example 2 was 48.2 μm. That is, the average particle size of the HCl or H2SO4-acid-treated magnesium silicate was observed to be larger than that of the comparative example.

[0099]

[0100] Experimental Example 4. Surface Area Analysis of Acid-Treated Magnesium Silicate

[0101] The specific surface areas (BET) of the HCl-treated magnesium silicate prepared in Example 1, the H2SO4-treated magnesium silicate prepared in Example 2, and the non-acid-treated magnesium silicate prepared in Comparative Example 1 were analyzed. The specific surface areas were analyzed based on ASTM-D1933-03 or KS A ISO9277, and the results are shown in Table 3.

[0102]

[0103] Specific surface area (m 2 / g) Comparative Example 104.8190 Example 1405.7412 Example 2492.6383

[0104]

[0105] Referring to Table 3, the specific surface area of ​​the non-acid-treated magnesium silicate manufactured in the above comparative example is 104.8190 m 2 / g. On the other hand, the specific surface area of ​​the HCl-treated magnesium silicate prepared in Example 1 was 405.7412 m 2 / g, and the specific surface area of ​​the magnesium silicate acid-treated with H2SO4 prepared in Example 2 was 492.6383 m 2 / g was confirmed.

[0106]

[0107] Experimental Example 5. Analysis of the ammonia adsorption capacity of acid-treated magnesium silicate.

[0108] The ammonia adsorption capacity of the HCl-treated magnesium silicate prepared in Example 1, the H2SO4-treated magnesium silicate prepared in Example 2, and the non-acid-treated magnesium silicate prepared in Comparative Example 1 was analyzed. The ammonia adsorption capacity was analyzed through the ammonia temperature-induced desorption method (NH3-TPD), and the results are shown in FIGS. 2 to 4 and Table 4. More specifically, the ammonia adsorption amounts (mmol / g) of Examples 1 and 2 and the Comparative Example are shown in Table 4, and FIG. 2 shows a graph of the ammonia adsorption amount of the magnesium silicate prepared in the Comparative Example, FIG. 3 shows a graph of the ammonia adsorption amount of the magnesium silicate prepared in Example 1, and FIG. 4 shows a graph of the ammonia adsorption amount of the magnesium silicate prepared in Example 2.

[0109] The samples prepared in Examples 1, 2, and Comparative Examples were first pretreated by exposing them to He at 200°C for 60 minutes, and then cooled to 100°C in the same gas environment. Next, they were exposed to 10% NH3 / He at 100°C for 60 minutes, and then to He for 30 minutes. Finally, TPD was performed from 100 to 800°C in an environment exposed to He.

[0110]

[0111] Ammonia adsorption amount (mmol / g) Comparative example 0.86 Example 11.44 Example 21.53

[0112]

[0113] Referring to FIGS. 2 to 4 and Table 4, the ammonia adsorption amount of the non-acid-treated magnesium silicate prepared in the comparative example was 0.86 mmol / g. On the other hand, the ammonia adsorption amount of the HCl-acid-treated magnesium silicate prepared in Example 1 was 1.44 mmol / g, and the H2SO4-acid-treated magnesium silicate prepared in Example 2 was 1.53 mmol / g.

[0114] That is, it was confirmed that the ammonia adsorption amount of magnesium silicate treated with HCl or H2SO4 was higher than that of magnesium silicate that was not treated with acid, and among them, the ammonia adsorption amount of magnesium silicate treated with H2SO4 was higher than that of HCl.

[0115]

[0116] From the above description, those skilled in the art will understand that the present invention can be implemented in other specific forms without altering its technical spirit or essential features. In this regard, it should be understood that the embodiments described above are illustrative in all respects and are not limiting.

Claims

1. Contains acid-treated magnesium silicate after heat treatment, The above acid treatment An ammonia adsorbent characterized by reacting heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution.

2. In paragraph 1, After the above heat treatment, the acid-treated magnesium silicate An ammonia adsorbent characterized by an oxygen content of 50 to 56 wt%, a magnesium content of 9 to 11 wt%, and a silicon content of 33 to 39 wt%.

3. In paragraph 1, After the above heat treatment, the acid-treated magnesium silicate Specific surface area of ​​400 to 500 m 2 / g and an ammonia adsorbent characterized by an average particle size of 30 to 50 μm. 4.a) Step of manufacturing magnesium silicate; b) A step of heat treating the manufactured magnesium silicate; c) a step of producing acid-treated magnesium silicate by reacting the heat-treated magnesium silicate with a hydrochloric acid (HCl) solution or a sulfuric acid (H2SO4) solution; d) a step of preparing a mixture by mixing the above acid-treated magnesium silicate, organic binder and inorganic binder; and e) a step of drying the mixture; A method for producing an ammonia adsorbent comprising magnesium silicate.

5. In paragraph 4, Step c) above Characterized in that the heat-treated magnesium silicate is mixed at 1 to 3% (w / v) in a 0.1 to 0.5 M hydrochloric acid (HCl) solution or a 0.5 to 1.0 M sulfuric acid (H2SO4) solution and reacted. A method for producing an ammonia adsorbent comprising magnesium silicate.

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