Sulfur oxide adsorption component, sulfur oxide adsorbent, method for adsorbing and desorbing sulfur oxide, and exhaust gas treatment system

Abstract

A sulfur oxide adsorption component contains manganese oxide, the crystal structure of the manganese oxide being tetragonal and / or hexagonal.

Description

Sulfur oxide adsorption component, sulfur oxide adsorbent, method for adsorption and desorption of sulfur oxides, and exhaust gas treatment system

[0001] The present invention relates to a sulfur oxide adsorption component, a sulfur oxide adsorbent, a method for adsorbing and desorbing sulfur oxides, and an exhaust gas treatment system.

[0002] Harmful substances (e.g., hydrocarbons, nitrogen oxides, etc.) contained in exhaust gases emitted from internal combustion engines and other sources contribute to air pollution. Therefore, a technology is known that involves placing a catalyst (exhaust gas treatment catalyst) in the exhaust passage through which the exhaust gas flows to treat these harmful substances. However, if the exhaust gas emitted from internal combustion engines and other sources contains sulfur oxides, contact between the sulfur oxides and the exhaust gas treatment catalyst may degrade the performance of the exhaust gas treatment catalyst (e.g., its ability to treat harmful substances).

[0003] Therefore, it is being considered to place a sulfur oxide adsorbent upstream of the exhaust gas treatment catalyst (upstream in the direction of exhaust gas flow) in the exhaust passage through which the exhaust gas flows. Patent Document 1 lists a sulfur oxide adsorbent made of silica zeolite as such an adsorbent. Patent Document 1 also states that a sulfur oxide adsorbent made of silica zeolite can adsorb sulfur oxides in the range of 50°C to 200°C and desorb the adsorbed sulfur oxides in the range of 200°C to 350°C.

[0004] Japanese Patent Publication No. 2004-275806

[0005] On the other hand, depending on the type of exhaust gas treatment catalyst placed downstream of the sulfur oxide adsorbent (downstream in the direction of exhaust gas flow), some exhibit high activity in environments with higher temperatures (specifically, 350°C or higher). Therefore, sulfur oxide adsorbents need to have high sulfur oxide adsorption capacity in environments with higher temperatures. However, the sulfur oxide adsorbent described in Patent Document 1 desorbs adsorbed sulfur oxides in relatively high-temperature environments such as 350°C or higher. Therefore, the sulfur oxide adsorbent described in Patent Document 1 has the drawback of not being usable in relatively high-temperature environments such as 350°C or higher.

[0006] The present invention aims to provide a sulfur oxide adsorbent component, a sulfur oxide adsorbent, a method for adsorbing and desorbing sulfur oxides, and an exhaust gas treatment system that have high sulfur oxide adsorption capacity in a relatively high-temperature environment.

[0007] The present invention [1] includes a sulfur oxide adsorbent component containing manganese oxide, wherein the crystalline structure of the manganese oxide is tetragonal and / or hexagonal.

[0008] The present invention [2] includes the sulfur oxide adsorbent described in [1] above, wherein the sulfur oxide adsorbent further contains iron oxide, and the molar ratio of manganese in manganese oxide to iron in the iron oxide (Mn / Fe) is 0.21 or more and 4.50 or less.

[0009] The present invention [3] includes the sulfur oxide adsorbent component described in [2] above, wherein the molar ratio (Mn / Fe) of manganese in manganese oxide to iron in iron oxide is 0.26 or more and 2.84 or less.

[0010] The present invention [4] relates to a manganese oxide which is trivalent manganese oxide (Mn ２ O ３ ) and / or tetravalent manganese oxide (MnO ２ ) consists of, and the iron oxide is trivalent iron oxide (Fe ２ O ３ ) comprises the sulfur oxide adsorbent component described in [2] above, wherein the crystal structure of the iron oxide is hexagonal.

[0011] The present invention [5] includes the sulfur oxide adsorbent described in [1] above, wherein the sulfur oxide adsorbent further contains copper oxide, and the molar ratio of manganese in manganese oxide to copper in the copper oxide (Mn / Cu) is 1.00 or more and 9.00 or less.

[0012] The present invention [6] includes the sulfur oxide adsorbent component described in [5] above, wherein the molar ratio (Mn / Cu) of manganese in manganese oxide to copper in copper oxide is 1.22 or more and 5.67 or less.

[0013] The present invention [7] relates to a manganese oxide that is trivalent manganese oxide (Mn ２ O ３), and / or tetravalent manganese oxide (MnO ２ ), the copper oxide is composed of divalent copper oxide (CuO), and the crystal structure of the copper oxide is monoclinic, and includes the sulfur oxide adsorbing component described in the above [5].

[0014] The present invention [8] includes a sulfur oxide adsorbent comprising the sulfur oxide adsorbing component according to any one of the above [1] to [7], an inorganic binder, and a carrier carrying the sulfur oxide adsorbing component and the inorganic binder.

[0015] The present invention [9] is a method for adsorbing and desorbing sulfur oxides using the sulfur oxide adsorbent described in the above [8], wherein the sulfur oxide adsorbent adsorbs sulfur oxides at 300°C or higher and 600°C or lower, and includes a method for adsorbing and desorbing sulfur oxides.

[0016] The present invention

[10] is a method for adsorbing and desorbing sulfur oxides using the sulfur oxide adsorbent described in the above [8], wherein the sulfur oxide adsorbent desorbs sulfur oxides at 680°C or higher, and includes a method for adsorbing and desorbing sulfur oxides.

[0017] The present invention

[11] is an exhaust gas treatment system for treating exhaust gas discharged from an internal combustion engine and containing sulfur oxides, comprising a sulfur oxide adsorbing section having the sulfur oxide adsorbent described in the above [8], and an exhaust gas treatment section disposed downstream of the sulfur oxide adsorbing section and having at least one selected from the group consisting of a denitration catalyst, an ammonia decomposition catalyst, an N ２ O decomposition catalyst, and a methane oxidation catalyst, and includes an exhaust gas treatment system.

[0018] The sulfur oxide adsorbing component of the present invention contains manganese oxide, and the crystal structure of the manganese oxide is cubic and / or hexagonal. Therefore, it has high sulfur oxide adsorbing property in a relatively high-temperature environment.

[0019] The sulfur oxide adsorbent of the present invention includes the above sulfur oxide adsorbing component, an inorganic binder, and a carrier carrying the sulfur oxide adsorbing component and the inorganic binder. Therefore, the above sulfur oxide adsorbing component can increase the area in contact with the exhaust gas. As a result, sulfur oxides can be adsorbed more efficiently in a relatively high-temperature environment.

[0020] The present invention provides a method for adsorbing and desorbing sulfur oxides using the above-described sulfur oxide adsorbent, which adsorbs sulfur oxides at temperatures between 300°C and 600°C. Therefore, it is suitable for adsorbing sulfur oxides in relatively high-temperature environments.

[0021] The present invention provides a method for adsorbing and desorbing sulfur oxides using the above-described sulfur oxide adsorbent, which desorbs sulfur oxides at temperatures of 680°C or higher. Therefore, it is possible to regenerate the sulfur oxide adsorbent in higher temperature environments.

[0022] The exhaust gas treatment system of the present invention is an exhaust gas treatment system that treats exhaust gas discharged from an internal combustion engine and containing sulfur oxides, and comprises a sulfur oxide adsorption section having the above-mentioned sulfur oxide adsorbent, and a denitrification catalyst, ammonia decomposition catalyst, and N2, which are arranged downstream of the sulfur oxide adsorption section. ２ The system includes an exhaust gas treatment section having at least one selected from the group consisting of an oxygen decomposition catalyst and a methane oxidation catalyst. Even in relatively high-temperature environments, the sulfur oxide adsorption section has high sulfur oxide adsorption capacity, thereby suppressing the performance degradation of the catalyst in the exhaust gas treatment catalyst section and enabling efficient exhaust gas treatment.

[0023] Figure 1 is a schematic diagram of one embodiment of the exhaust gas treatment system of the present invention. Figure 2 is a perspective view of the sulfur oxide adsorption section in the exhaust gas treatment system of Figure 1. Figure 3 shows the X-ray diffraction spectrum of the sulfur oxide adsorbent component in the sulfur oxide adsorbent of Example 8. Figure 4 shows the X-ray diffraction spectrum of the sulfur oxide adsorbent component in the sulfur oxide adsorbent of Example 13. Figure 5 shows the X-ray photoelectron spectroscopy spectra of the sulfur oxide adsorbent component in the sulfur oxide adsorbents of Examples 1 to 9. Figure 6 shows the X-ray photoelectron spectroscopy spectra of the sulfur oxide adsorbent component in the sulfur oxide adsorbents of Examples 11 to 15. Figure 7 is a graph in which the X-axis represents the manganese content ratio to the total amount of sulfur oxide adsorbent component and the sulfur dioxide adsorption rate at 400°C is shown on the Y-axis for the sulfur oxide adsorbents of Examples 1 to 10 and Comparative Example 1. Figure 8 is a graph in which the X-axis represents the manganese content ratio to the total amount of sulfur oxide adsorbent component and the sulfur dioxide adsorption rate at 400°C is shown on the Y-axis for the sulfur oxide adsorbents of Examples 10 to 15. Figure 9 is a graph showing the desorption of sulfur dioxide with increasing temperature in Example 8.

[0024] 1. Sulfur Oxide Adsorbents Sulfur oxide adsorbents adsorb sulfur oxides (e.g., sulfur dioxide) contained in exhaust gas. Such sulfur oxide adsorbents can be used, for example, to adsorb sulfur oxides contained in exhaust gas discharged from LNG-fueled ships, and to adsorb sulfur oxides contained in gases generated in processes such as gas-phase reactions in chemical plants.

[0025] A sulfur oxide adsorbent comprises a sulfur oxide adsorbent component. Preferably, the sulfur oxide adsorbent further comprises an inorganic binder and a carrier that supports the sulfur oxide adsorbent component and the inorganic binder.

[0026] The sulfur oxide adsorbent is, for example, a flat plate and / or corrugated plate that extends in planar directions (first and second directions) perpendicular to the thickness direction. Preferably, it is a flat plate and / or corrugated plate that extends in the first direction (the direction of exhaust gas flow).

[0027] If the sulfur oxide adsorbent is shaped like a flat plate and / or a corrugated plate, the surface area of ​​the sulfur oxide adsorbent in contact with the exhaust gas can be increased. As a result, sulfur oxides can be adsorbed more efficiently in relatively high-temperature environments.

[0028] 1.1. Sulfur Oxide Adsorption Components The sulfur oxide adsorption components are components that adsorb sulfur oxides (e.g., sulfur dioxide) contained in exhaust gas. The sulfur oxide adsorption components are supported on a carrier, for example, as described later.

[0029] The sulfur oxide adsorbent component contains manganese oxide. Preferably, it further contains iron oxide and / or copper oxide.

[0030] The crystal structure of manganese oxide is tetragonal and / or hexagonal. That is, the crystal structure of manganese oxide may be tetragonal, hexagonal, or a mixture of tetragonal and hexagonal crystals. Preferably, it is tetragonal.

[0031] If the crystal structure of manganese oxide is tetragonal and / or hexagonal, it exhibits high sulfur oxide adsorption properties in relatively high-temperature environments.

[0032] The crystal structure of manganese oxide can be detected by X-ray diffraction (XRD) analysis. For example, if only tetragonal peaks are detected by XRD analysis of manganese oxide, the crystal structure of manganese oxide can be determined to be tetragonal. The conditions for XRD analysis will be described in the examples below. The same applies to the crystal structures of iron oxide and copper oxide, which will be described later.

[0033] The crystallite size of manganese oxide is, for example, 20 Å or more, preferably 30 Å or more, more preferably 40 Å or more, and also, for example, 300 Å or less, preferably 200 Å or less, more preferably 150 Å or less.

[0034] If the crystallite size of manganese oxide is below the above upper limit, the surface area per unit volume increases, which in turn increases the contact area with the exhaust gas and improves the adsorption capacity of sulfur oxides.

[0035] The crystallite size of manganese oxide can be measured by X-ray diffraction (XRD) analysis. The same method can be used to determine the crystallite sizes of iron oxide and copper oxide, which will be discussed later.

[0036] Examples of manganese oxide include divalent manganese oxide (MnO) and trivalent manganese oxide (Mn ２ O ３ ), and tetravalent manganese oxide (MnO ２ ) are examples. Manganese oxide is preferably trivalent manganese oxide (Mn ２ O ３ ) and / or tetravalent manganese oxide (MnO ２ ) consists of. In other words, manganese oxide is trivalent manganese oxide (Mn ２ O ３ ) may consist of tetravalent manganese oxide (MnO ２ ) may consist of trivalent manganese oxide (Mn ２ O ３ ) and tetravalent manganese oxide (MnO ２ ) may be derived from this.

[0037] Manganese oxide is trivalent manganese oxide (Mn ２ O ３ ) and / or tetravalent manganese oxide (MnO ２ Therefore, it has high sulfur oxide adsorption capacity in relatively high-temperature environments.

[0038] Furthermore, sulfur oxide adsorption capacity is an indicator based on the adsorption rate of sulfur oxides, as described later, and indicates the adsorption of sulfur oxides and the suppression of desorption of adsorbed sulfur oxides. In other words, high sulfur oxide adsorption capacity means that the adsorption rate of sulfur oxides is high, or to put it another way, that sulfur oxides are adsorbed with high efficiency while the desorption of adsorbed sulfur oxides is suppressed.

[0039] The valency of manganese oxide can be detected by X-ray photoelectron spectroscopy (XPS) analysis. The conditions for XPS analysis are described in the examples below. The same method is used for determining the valencies of iron oxide and copper oxide, which will be discussed later.

[0040] Furthermore, tetravalent manganese oxide (MnO ２When heated to a high temperature (for example, 530°C or higher), it undergoes thermal decomposition to form trivalent manganese oxide (Mn ２ O ３ ) is produced. In other words, in this embodiment, tetravalent manganese oxide (MnO ２ ) is used, and if thermal decomposition occurs during the exhaust gas treatment process (trivalent manganese oxide (Mn ２ O ３ Even if (such as) occurs, it can maintain high sulfur oxide adsorption capacity in relatively high-temperature environments.

[0041] The specific surface area of ​​manganese oxide is, for example, 30 m². ２ / g or more, preferably 50m ２ / g or more, more preferably 100m ２ It is 1 / g or more.

[0042] If the specific surface area of ​​manganese oxide is above the lower limit mentioned above, a sufficient contact area with the exhaust gas can be secured, thereby improving the adsorption capacity of sulfur oxides.

[0043] The average particle size of manganese oxide is, for example, 25 μm or less, preferably 20 μm or less, and more preferably 10 μm or less.

[0044] If the average particle size of manganese oxide is below the above upper limit, the dispersibility of the sulfur oxide adsorbent in the dispersion medium can be improved, and it can be uniformly supported on the carrier.

[0045] (First Embodiment) The first embodiment of the sulfur oxide adsorption component will be described below.

[0046] The sulfur oxide adsorption component of the first embodiment further contains iron oxide. That is, the sulfur oxide adsorption component of the first embodiment contains manganese oxide and iron oxide. In this embodiment, the sulfur oxide adsorption component of the first embodiment consists of manganese oxide and iron oxide. Furthermore, the sulfur oxide adsorption component of the first embodiment preferably does not contain a composite oxide of manganese and iron.

[0047] The absence of manganese-iron composite oxides in the sulfur oxide adsorption component of the first embodiment can be confirmed by X-ray diffraction (XRD) analysis. Specifically, if no peaks of manganese-iron composite oxides are detected in the X-ray diffraction (XRD) analysis, the sulfur oxide adsorption component of the first embodiment is considered to be free of manganese-iron composite oxides. The conditions for the X-ray diffraction (XRD) analysis are described in the examples below.

[0048] If the sulfur oxide adsorbent component contains iron oxide, the oxidation of sulfur oxides can be promoted, thereby improving the sulfur oxide adsorption capacity of manganese oxide. Furthermore, when preparing the sulfur oxide adsorbent, the dispersibility of manganese oxide in the dispersion medium can be improved.

[0049] Examples of iron oxides include trivalent iron oxide (Fe ２ O ３ ) are examples. The iron oxide is preferably trivalent iron oxide (Fe ２ O ３ ) consists of.

[0050] Iron oxide is trivalent iron oxide (Fe ２ O ３ Therefore, sulfur oxide adsorption can be improved in relatively high-temperature environments.

[0051] One example of the crystalline structure of iron oxide is hexagonal.

[0052] If the crystal structure of iron oxide is hexagonal, its sulfur oxide adsorption properties can be improved in relatively high-temperature environments.

[0053] The crystallite size of iron oxide is, for example, 40 Å or more, preferably 60 Å or more, more preferably 80 Å or more, and also, for example, 1500 Å or less, preferably 1200 Å or less, more preferably 1000 Å or less, even more preferably 500 Å or less, and particularly preferably 200 Å or less.

[0054] If the crystallite size of iron oxide is below the above upper limit, the surface area per unit volume increases, which increases the contact area with exhaust gas and improves sulfur oxide adsorption.

[0055] The specific surface area of ​​iron oxide is, for example, 50 m². ２ / g or more, preferably 100m ２ / g or more, more preferably 140m ２ It is 1 / g or more.

[0056] If the specific surface area of ​​iron oxide is above the lower limit mentioned above, the dispersibility of manganese oxide in the dispersion medium can be improved when preparing a sulfur oxide adsorbent.

[0057] The average particle size of iron oxide is, for example, 30 μm or less, preferably 20 μm or less, and more preferably 10 μm or less.

[0058] If the average particle size of iron oxide is below the above upper limit, the dispersibility of the sulfur oxide adsorbent in the dispersion medium can be improved when preparing it, and it can be uniformly supported on the carrier.

[0059] The sulfur oxide adsorbent component of the first embodiment may contain other adsorbent components besides manganese oxide and iron oxide. Examples of other adsorbent components include metals (including manganese and iron) and other metal oxides other than manganese oxide and iron oxide. In this embodiment, the sulfur oxide adsorbent component of the first embodiment preferably does not contain other adsorbent components other than manganese oxide and iron oxide, or contains them in trace amounts as unavoidable impurities. Note that containing trace amounts as unavoidable impurities means that the content of unavoidable impurities in the sulfur oxide adsorbent component of the first embodiment is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less.

[0060] Examples of metals include Ni, Co, Mn, Fe, and Cu. Other metal oxides besides manganese oxide and iron oxide include nickel oxide, cobalt oxide, and copper oxide.

[0061] In the sulfur oxide adsorption component of the first embodiment, the molar ratio of manganese in manganese oxide to iron in iron oxide (Mn / Fe) is, for example, 0.21 to 4.50, preferably 0.26 to 2.84, more preferably 0.30 to 2.50, even more preferably 0.33 to 2.30, particularly preferably 0.50 to 2.30, and most preferably 0.75 to 2.30.

[0062] In the sulfur oxide adsorption component of the first embodiment, the molar ratio of manganese in manganese oxide to iron in iron oxide (Mn / Fe) is, for example, 0.21 or more, preferably 0.26 or more, more preferably 0.30 or more, even more preferably 0.33 or more, particularly preferably 0.50 or more, most preferably 0.75 or more, and also, for example, 4.50 or less, preferably 2.84 or less, more preferably 2.50 or less, and even more preferably 2.30 or less.

[0063] In the sulfur oxide adsorption component of the first embodiment, if the molar ratio of manganese in manganese oxide to iron in iron oxide (Mn / Fe) is within the above range, it exhibits high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0064] In the first embodiment, the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component (the total number of moles of metal in the metal oxide if it is a metal oxide) (the number of moles of Mn / the total number of moles of metal × 100) is, for example, 17% to 82%, preferably 20% to 74%, and more preferably 23% to 71%.

[0065] The ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first embodiment (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Mn / total number of moles of metal × 100) is, for example, 17% or more, preferably 20% or more, more preferably 23% or more, and also, for example, 82% or less, preferably 74% or less, more preferably 71% or less.

[0066] If the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorption component of the first embodiment (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Mn / total number of moles of metal × 100) is within the above range, it will have high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0067] In the first embodiment, the ratio of the number of moles of iron in iron oxide to the total number of moles of metal in the sulfur oxide adsorbent component (the total number of moles of metal in the metal oxide if it is a metal oxide) (the number of moles of Fe / the total number of moles of metal × 100) is, for example, 18% to 83%, preferably 26% to 80%, and more preferably 29% to 77%.

[0068] The ratio of the number of moles of iron in iron oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first embodiment (the total number of moles of metal in the metal oxide if it is a metal oxide) (the number of moles of Fe / the total number of moles of metal × 100) is, for example, 18% or more, preferably 26% or more, more preferably 29% or more, and also, for example, 83% or less, preferably 80% or less, more preferably 77% or less.

[0069] If the ratio of the number of moles of iron in iron oxide to the total number of moles of metal in the sulfur oxide adsorption component of the first embodiment (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Fe / total number of moles of metal × 100) is within the above range, the sulfur oxide adsorption performance can be improved in a relatively high-temperature environment.

[0070] The total number of moles of metal in the sulfur oxide adsorption component of the first embodiment (or, in the case of a metal oxide, the total number of moles of metal in the metal oxide) is the total number of moles of metal in the manganese oxide, iron oxide, and other adsorbent components contained in the sulfur oxide adsorption component of the first embodiment. If the sulfur oxide adsorption component of the first embodiment consists of manganese oxide and iron oxide, it is the total number of moles of manganese and iron.

[0071] The manganese content ratio (= manganese content (moles) / total amount of sulfur oxide adsorbent components in the first embodiment (total moles) × 100) relative to the total amount of sulfur oxide adsorbent components in the first embodiment is, for example, 30 mol% to 90 mol%, preferably 35 mol% to 85 mol%, more preferably 38 mol% to 82 mol%, even more preferably 40 mol% to 82 mol%, particularly preferably 50 mol% to 82 mol%, and most preferably 60 mol% to 82 mol%.

[0072] The manganese content ratio (= manganese content (moles) / total amount of sulfur oxide adsorbent components in the first embodiment (total moles) × 100) relative to the total amount of sulfur oxide adsorbent components in the first embodiment is 30 mol% or more, preferably 35 mol% or more, more preferably 38 mol% or more, even more preferably 40 mol% or more, particularly preferably 50 mol% or more, most preferably 60 mol% or more, and also 90 mol% or less, preferably 85 mol% or less, and more preferably 82 mol or less.

[0073] If the manganese content relative to the total amount of sulfur oxide adsorbing components in the first embodiment is within the above range, it exhibits high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0074] The ratio of iron oxide content to the total amount of sulfur oxide adsorbent components in the first embodiment (= iron oxide content (moles) / total amount of sulfur oxide adsorbent components in the first embodiment (total moles) × 100) is, for example, 10 mol% to 70 mol%, preferably 15 mol% to 65 mol%, more preferably 18 mol% to 62 mol%, even more preferably 18 mol% to 60 mol%, particularly preferably 18 mol% to 50 mol%, and most preferably 18 mol% to 40 mol%.

[0075] The ratio of iron oxide content to the total amount of sulfur oxide adsorbent components in the first embodiment (= iron oxide content (moles) / total amount of sulfur oxide adsorbent components in the first embodiment (total moles) × 100) is, for example, 10 mol% or more, preferably 15 mol% or more, more preferably 18 mol% or more, and also, for example, 70 mol% or less, preferably 65 mol% or less, more preferably 62 mol% or less, even more preferably 60 mol% or less, particularly preferably 50 mol% or less, and most preferably 40 mol% or less.

[0076] If the ratio of iron oxide content to the total amount of sulfur oxide adsorbing components in the first embodiment is within the above range, the sulfur oxide adsorption performance can be improved in a relatively high-temperature environment.

[0077] The total amount of the sulfur oxide adsorbent component in the first embodiment described above is the total number of moles of manganese oxide, iron oxide, and other adsorbent components contained in the sulfur oxide adsorbent component of the first embodiment. If the sulfur oxide adsorbent component of the first embodiment consists of manganese oxide and iron oxide, it is the total number of moles of manganese oxide and iron oxide.

[0078] The sulfur oxide adsorbent component of the first embodiment is tetravalent manganese oxide (MnO ２ ) and trivalent iron oxide (Fe ２ O ３ When it consists of ), in the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS), trivalent iron (Fe ３＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Fe ３＋ The peak intensity is, for example, 0.043 to 1.172, preferably 0.059 to 0.788, more preferably 0.072 to 0.788, even more preferably 0.119 to 0.788, particularly preferably 0.147 to 0.788, and most preferably 0.326 to 0.788.

[0079] The sulfur oxide adsorbent component of the first embodiment is tetravalent manganese oxide (MnO ２ ) and trivalent iron oxide (Fe ２ O３ When it consists of ), in the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS), trivalent iron (Fe ３＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Fe ３＋ The peak intensity is, for example, 0.043 or higher, preferably 0.059 or higher, more preferably 0.072 or higher, even more preferably 0.119 or higher, particularly preferably 0.147 or higher, most preferably 0.326 or higher, and also, for example, 1.172 or lower, preferably 0.788 or lower.

[0080] In the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS), trivalent iron (Fe ３＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Fe ３＋ If the peak intensity is within the above range, it exhibits high sulfur oxide adsorption properties in relatively high-temperature environments.

[0081] In addition, X-ray photoelectron spectroscopy (XPS) analysis revealed peaks for tetravalent manganese at 641.0 eV to 642.5 eV, and peaks for trivalent iron at 709.9 eV to 711.6 eV.

[0082] The carrier described later, 1m ２ The amount of sulfur oxide adsorbent component supported per unit area in the first embodiment is, for example, 150 g / m². ２ Preferably, 200 g / m² ２ Above all, comfortably, 250 g / m ２ In addition, for example, 300 g / m ２ The following applies:

[0083] The carrier described later, 1m ２ If the amount of sulfur oxide adsorbent supported per unit of the first embodiment is equal to or greater than the above lower limit, the sulfur oxide adsorbent is superior in terms of manufacturing cost.

[0084] (Second Embodiment) A second embodiment of the sulfur oxide adsorption component is described below.

[0085] The sulfur oxide adsorption component of the second embodiment further contains copper oxide. That is, the sulfur oxide adsorption component of the second embodiment contains manganese oxide and copper oxide. In this embodiment, the sulfur oxide adsorption component of the second embodiment consists of manganese oxide and copper oxide. Furthermore, the sulfur oxide adsorption component of the second embodiment preferably does not contain a composite oxide of manganese and copper.

[0086] The absence of manganese-copper composite oxides in the sulfur oxide adsorption component of the second embodiment can be confirmed by X-ray diffraction (XRD) analysis. Specifically, if no peaks of manganese-copper composite oxides are detected in the X-ray diffraction (XRD) analysis, the sulfur oxide adsorption component of the second embodiment is considered to be free of manganese-copper composite oxides. The conditions for the X-ray diffraction (XRD) analysis are described in the examples below.

[0087] If the sulfur oxide adsorbent component contains copper oxide, the oxidation of sulfur oxides can be promoted, thereby improving the sulfur oxide adsorption capacity of manganese oxide. Furthermore, when preparing the sulfur oxide adsorbent, the dispersibility of manganese oxide in the dispersion medium can be improved.

[0088] Examples of copper oxide include divalent copper oxide (CuO). Preferably, the copper oxide consists of divalent copper oxide (CuO).

[0089] If the copper oxide is divalent copper oxide (CuO), its sulfur oxide adsorption properties can be improved in relatively high-temperature environments.

[0090] For example, the crystal structure of copper oxide is monoclinic.

[0091] If the crystal structure of copper oxide is monoclinic, its sulfur oxide adsorption properties can be improved in relatively high-temperature environments.

[0092] The crystallite size of copper oxide is, for example, 200 Å or more, preferably 250 Å or more, more preferably 300 Å or more, and also, for example, 1200 Å or less, preferably 1000 Å or less, more preferably 800 Å or less, and even more preferably 700 Å or less.

[0093] If the crystallite size of copper oxide is below the above upper limit, the surface area per unit volume increases, which increases the contact area with the exhaust gas and improves the adsorption capacity of sulfur oxides.

[0094] The specific surface area of ​​copper oxide is, for example, 30 m². ２ / g or more, preferably 50m ２ / g or more, more preferably 100m ２ It is 1 / g or more.

[0095] If the specific surface area of ​​copper oxide is above the lower limit mentioned above, the dispersibility of manganese oxide in the dispersion medium can be improved when preparing a sulfur oxide adsorbent.

[0096] The average particle size of copper oxide is, for example, 30 μm or less, preferably 20 μm or less, and more preferably 10 μm or less.

[0097] If the average particle size of copper oxide is below the above upper limit, the dispersibility of the sulfur oxide adsorbent in the dispersion medium can be improved when preparing it, and it can be uniformly supported on the carrier.

[0098] The sulfur oxide adsorbent component of the second embodiment may contain other adsorbent components besides manganese oxide and copper oxide. Examples of other adsorbent components include metals (including manganese and copper) and other metal oxides other than manganese oxide and copper oxide. In this embodiment, the sulfur oxide adsorbent component of the second embodiment preferably does not contain other adsorbent components other than manganese oxide and copper oxide, or contains them in trace amounts as unavoidable impurities. Note that containing trace amounts as unavoidable impurities means that the content of unavoidable impurities in the sulfur oxide adsorbent component of the second embodiment is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.1% by mass or less.

[0099] Examples of metals include Ni, Co, Mn, Fe, and Cu. Other metal oxides besides manganese oxide and copper oxide include nickel oxide, cobalt oxide, and iron oxide.

[0100] In the sulfur oxide adsorption component of the second embodiment, the molar ratio of manganese in manganese oxide to copper in copper oxide (Mn / Cu) is, for example, 1.00 to 9.00, preferably 1.22 to 5.67, more preferably 1.35 to 4.60, and even more preferably 1.50 to 4.00.

[0101] In the sulfur oxide adsorption component of the second embodiment, the molar ratio of manganese in manganese oxide to copper in copper oxide (Mn / Cu) is, for example, 1.00 or more, preferably 1.22 or more, more preferably 1.35 or more, even more preferably 1.50 or more, and also, for example, 9.00 or less, preferably 5.67 or less, more preferably 4.60 or less, even more preferably 4.00 or less.

[0102] In the sulfur oxide adsorption component of the second embodiment, if the molar ratio of manganese in manganese oxide to copper in copper oxide (Mn / Cu) is within the above range, it exhibits high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0103] In the second embodiment, the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component (the total number of moles of metal in the metal oxide if it is a metal oxide) (the number of moles of Mn / the total number of moles of metal × 100) is, for example, 50% to 90%, preferably 55% to 85%, and more preferably 60% to 80%.

[0104] In the second embodiment, the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component (the total number of moles of metal in the metal oxide if it is a metal oxide) (the number of moles of Mn / the total number of moles of metal × 100) is, for example, 50% or more, preferably 55% or more, more preferably 60% or more, and also, for example, 90% or less, preferably 85% or less, more preferably 80% or less.

[0105] If the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorption component of the second embodiment (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Mn / total number of moles of metal × 100) is within the above range, it will have high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0106] In the second embodiment, the ratio of the number of moles of copper in copper oxide to the total number of moles of metal in the sulfur oxide adsorbent component (the total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Cu / total number of moles of metal × 100) is, for example, 10% to 50%, preferably 15% to 45%, and more preferably 20% to 40%.

[0107] In the second embodiment, the ratio of the number of moles of copper in copper oxide to the total number of moles of metal in the sulfur oxide adsorbent component (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Cu / total number of moles of metal × 100) is, for example, 10% or more, preferably 15% or more, more preferably 20% or more, and also, for example, 50% or less, preferably 45% or less, more preferably 40% or less.

[0108] If the ratio of the number of moles of copper in copper oxide to the total number of moles of metal in the sulfur oxide adsorption component of the second embodiment (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Cu / total number of moles of metal × 100) is within the above range, the sulfur oxide adsorption performance can be improved in a relatively high-temperature environment.

[0109] In the second embodiment, the total number of moles of metal in the sulfur oxide adsorption component (or, if it is a metal oxide, the total number of moles of metal in the metal oxide) is the total number of moles of metal in the manganese oxide, copper oxide, and other adsorbent components contained in the sulfur oxide adsorption component of the second embodiment. If the sulfur oxide adsorption component of the second embodiment consists of manganese oxide and copper oxide, it is the total number of moles of manganese and copper.

[0110] The ratio of manganese oxide content to the total amount of sulfur oxide adsorbent components in the second embodiment (= manganese oxide content (moles) / total amount of sulfur oxide adsorbent components in the second embodiment (total moles) × 100) is, for example, 50 mol% to 90 mol%, preferably 55 mol% to 85 mol%, more preferably 58 mol% to 82 mol%, even more preferably 60 mol% to 80 mol%, particularly preferably 62 mol% to 78 mol%, and most preferably 65 mol% to 75 mol%.

[0111] The manganese content ratio (= manganese content (moles) / total amount of sulfur oxide adsorbent components in the second embodiment (total moles) × 100) relative to the total amount of sulfur oxide adsorbent components in the second embodiment is 50 mol% or more, preferably 55 mol% or more, more preferably 58 mol% or more, even more preferably 60 mol% or more, particularly preferably 62 mol% or more, most preferably 65 mol% or more, and also 90 mol% or less, preferably 85 mol% or less, more preferably 82 mol% or less, even more preferably 80 mol% or less, particularly preferably 78 mol% or less, and most preferably 75 mol or less.

[0112] If the manganese content relative to the total amount of sulfur oxide adsorbing components in the second embodiment is within the above range, it exhibits high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0113] The ratio of copper oxide content to the total amount of sulfur oxide adsorbent components in the second embodiment (= copper oxide content (moles) / total amount of sulfur oxide adsorbent components in the second embodiment (total moles) × 100) is, for example, 10 mol% to 50 mol%, preferably 15 mol% to 45 mol%, more preferably 18 mol% to 42 mol%, even more preferably 20 mol% to 40 mol%, particularly preferably 22 mol% to 38 mol%, and most preferably 25 mol% to 35 mol%.

[0114] The ratio of copper oxide content to the total amount of sulfur oxide adsorbent components in the second embodiment (= copper oxide content (moles) / total amount of sulfur oxide adsorbent components in the second embodiment (total moles) × 100) is, for example, 10 mol% or more, preferably 15 mol% or more, more preferably 18 mol% or more, even more preferably 20 mol% or more, particularly preferably 22 mol% or more, most preferably 25 mol% or more, and also, for example, 50 mol% or less, preferably 45 mol% or less, more preferably 42 mol% or less, even more preferably 40 mol% or less, particularly preferably 38 mol% or less, most preferably 35 mol% or less.

[0115] If the ratio of copper oxide content to the total amount of sulfur oxide adsorption components in the second embodiment is within the above range, the sulfur oxide adsorption performance can be improved in a relatively high-temperature environment.

[0116] The total amount of the sulfur oxide adsorbent component in the second embodiment described above is the total number of moles of manganese oxide, copper oxide, and other adsorbent components contained in the sulfur oxide adsorbent component of the second embodiment. If the sulfur oxide adsorbent component of the second embodiment consists of manganese oxide and copper oxide, it is the total number of moles of manganese oxide and copper oxide.

[0117] The sulfur oxide adsorption component in the second embodiment is tetravalent manganese oxide (MnO ２ When it consists of iron (CuO) and divalent copper oxide (CuO), the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS) analysis shows that divalent iron (CuO) ２＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Cu ２＋ The peak intensity is, for example, 0.970 to 8.696, more preferably 1.336 to 3.496.

[0118] The sulfur oxide adsorption component in the second embodiment is tetravalent manganese oxide (MnO ２ When it consists of iron (CuO) and divalent copper oxide (CuO), the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS) analysis shows that divalent iron (CuO) ２＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Cu ２＋ The peak intensity is, for example, 0.970 or higher, more preferably 1.336 or higher, and also, for example, 8.696 or lower, more preferably 3.496 or lower.

[0119] In the XPS spectrum measured by X-ray photoelectron spectroscopy (XPS), divalent iron (Cu ２＋ ) relative to the peak intensity of tetravalent manganese (Mn ４＋ ) Ratio of peak intensity (Mn ４＋ Peak intensity of Cu ２＋If the peak intensity is within the above range, it has high sulfur oxide adsorption properties in a relatively high temperature environment.

[0120] In X-ray photoelectron spectroscopy (XPS) analysis, a peak of tetravalent manganese is detected at 641.0 eV to 642.5 eV, and a peak of divalent copper is detected at 933.0 eV to 933.6 eV.

[0121] The loading amount of the sulfur oxide adsorption component of the second embodiment per 1 m of the carrier described later is, for example, 150 g / m ２ or more, preferably 200 g / m ２ or more, more preferably 250 g / m ２ or more, and also, for example, 300 g / m ２ or less. ２

[0122] When the loading amount of the sulfur oxide adsorption component of the second embodiment per 1 m of the carrier described later is not less than the above lower limit value, the sulfur oxide adsorbent is excellent in manufacturing cost. ２

[0123] 1.2. Inorganic binder The inorganic binder increases the strength of the carrier described later. More specifically, when the sulfur oxide adsorbent contains an inorganic binder, in the manufacturing method of the sulfur oxide adsorbent described later, when a slurry containing a sulfur oxide adsorption component and an inorganic binder is prepared, the inorganic binder can be uniformly dispersed in the slurry. Therefore, when the slurry is applied to the carrier, the inorganic binder is uniformly applied to the carrier, and as a result, the strength of the sulfur oxide adsorbent can be improved.

[0124] Examples of the inorganic binder include metal oxides, metalloid oxides, and metal hydroxides. Preferably, metalloid oxides are mentioned.

[0125] Examples of the metal oxide include alumina and ceria. Examples of the metalloid oxide include silica. Examples of the metal hydroxide include iron hydroxide, aluminum hydroxide, and cerium hydroxide.

[0126] Inorganic binders can be used alone or in combination of two or more types. Specifically, the inorganic binder may include, for example, at least one selected from the group consisting of alumina, ceria, silica, iron hydroxide, aluminum hydroxide, and cerium hydroxide. Preferably, it includes at least one selected from the group consisting of alumina and silica. More preferably, it includes silica. Even more preferably, it consists of silica.

[0127] The carrier described later, 1m ２ The amount of inorganic binder supported per unit is, for example, 15 g / m². ２ Preferably, 20 g / m ２ More preferably, 25 g / m ２ In addition, for example, 30 g / m ２ The following applies:

[0128] The carrier described later, 1m ２ If the amount of inorganic binder supported per unit is above the lower limit mentioned above, the strength of the carrier can be sufficiently increased.

[0129] The amount of inorganic binder added per 100 parts by mass of sulfur oxide adsorbent is, for example, 9 parts by mass or more, preferably 11 parts by mass or more, and for example, 25 parts by mass or less, preferably 18 parts by mass or less.

[0130] The amount of inorganic binder to be added per 100 parts by mass of sulfur oxide adsorbent is a value calculated from the amount of sulfur oxide adsorbent and the amount of inorganic binder (solid content).

[0131] 1.3. The carrier supports the above-mentioned sulfur oxide adsorbent and inorganic binder.

[0132] Examples of carriers include inorganic fiber sheets. Examples of inorganic fiber sheets include glass paper and ceramic paper. Glass paper is preferred.

[0133] Commercially available glass paper containing an organic binder can also be used. Examples of organic binders used in commercially available glass paper include acrylic resin, polyvinyl alcohol (PVA) / polyvinyl acetate copolymer, unsaturated polyester resin, and epoxy resin.

[0134] The shape of the carrier is, for example, a flat plate and / or corrugated plate that extends in planar directions (first and second directions) perpendicular to the thickness direction. Preferably, it is a flat plate and / or corrugated plate that extends in the first direction (the direction of exhaust gas flow). The shape of the carrier constitutes the shape of the sulfur oxide adsorbent. The carrier is preferably a flat glass paper and / or corrugated glass paper.

[0135] The dimensions of the carrier are adjusted as appropriate according to the exhaust gas flow rate and other factors. Specifically, the length of the carrier in the first direction (direction of exhaust gas flow) and the length in the second direction (width direction) perpendicular to the first direction are not particularly limited. However, it is preferable that the length of the carrier in the first direction (direction of exhaust gas flow) is longer than the length of the carrier in the second direction (width direction).

[0136] 1.4. Additives may be added to the sulfur oxide adsorbent as needed.

[0137] The additives are not particularly limited, as long as they are additives commonly used in sulfur oxide adsorbents, and examples include diluents.

[0138] The diluent is a substance that does not adsorb sulfur oxides, and by adding the diluent to the sulfur oxide adsorbent, temperature control can be easily achieved.

[0139] 1.5. Method for Manufacturing Sulfur Oxide Adsorbents The method for manufacturing the above-mentioned sulfur oxide adsorbents will be described below.

[0140] A method for producing a sulfur oxide adsorbent comprises, in order, a preparation step of preparing a slurry containing a sulfur oxide adsorbent component and an inorganic binder, a coating step of coating a carrier with the slurry, and a firing step of firing the carrier coated with the slurry.

[0141] (Preparation Step) In the preparation step, a slurry containing a sulfur oxide adsorbent and an inorganic binder is prepared. Specifically, the sulfur oxide adsorbent and the inorganic binder are dispersed in a dispersion medium to obtain a slurry. Note that the inorganic binder may be used in a sol state (a state in which the inorganic binder is dispersed in the dispersion medium described later).

[0142] The dispersion medium is not particularly limited as long as it can disperse the sulfur oxide adsorbent and the inorganic binder. Examples of dispersion mediums include water (e.g., deionized water and ultrapure water) and organic solvents. Water is preferred.

[0143] Furthermore, if the dispersion medium is water, it may also contain alcohols, carboxylic acids, etc.

[0144] (Coating process) In the coating process, the slurry obtained in the preparation process is coated onto the carrier.

[0145] Examples of coating methods include the so-called dipping method, brush application method, spray application method, and drip application method. The brush application method is preferred.

[0146] When applying slurry to a carrier using a brush application method, the slurry obtained in the preparation step is dropped onto the carrier and spread over the carrier using a brush.

[0147] (Firing Process) In the firing process, the carrier coated with slurry is fired. More specifically, the carrier coated with slurry is dried and then fired.

[0148] One drying method involves placing a carrier coated with slurry onto a heated mold and drying the slurry.

[0149] The drying temperature (mold heating temperature) is, for example, between 70°C and 150°C. The drying time is, for example, between 0.5 hours and 50 hours.

[0150] When the shape of the coated carrier after drying the slurry is to be flat, a flat mold is used for drying. When the shape of the coated carrier after drying the slurry is to be corrugated, the carrier is molded into a corrugated shape during drying. Specifically, the coated carrier is placed in a heated corrugated mold, and the molding is performed using a jig.

[0151] Next, the carrier coated with the dried slurry is fired.

[0152] The firing method is not particularly limited, and known methods can be used. The carrier coated with the dried slurry can be fired in a stacked state. Specifically, flat carriers coated with the dried slurry and corrugated flat carriers coated with the dried slurry can be stacked alternately and fired.

[0153] The firing temperature is, for example, between 300°C and 800°C. The firing time is, for example, between 1 minute and 10 hours.

[0154] In this way, a sulfur oxide adsorbent can be obtained.

[0155] 1.6. Modified Examples of Sulfur Oxide Adsorbent In the modified examples, the same reference numerals are used for components and processes as in the above embodiment of the sulfur oxide adsorbent, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects as the above embodiment of the sulfur oxide adsorbent unless otherwise specified. In addition, the above embodiment and modified examples of the sulfur oxide adsorbent can be combined as appropriate.

[0156] [First Modified Example] In the above-described sulfur oxide adsorbent, the sulfur oxide adsorbent component is the sulfur oxide adsorbent component of the first embodiment, consisting of manganese oxide and iron oxide, or the sulfur oxide adsorbent component of the second embodiment, consisting of manganese oxide and copper oxide, but is not limited thereto.

[0157] Specifically, the sulfur oxide adsorption component may consist of manganese oxide, iron oxide, and copper oxide. Manganese oxide, iron oxide, and copper oxide are the same as those described in the first embodiment and the second embodiment of the sulfur oxide adsorption component described above.

[0158] The ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Mn / total number of moles of metal × 100) is, for example, 20% to 90%, preferably 25% to 80%.

[0159] The ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Mn / total number of moles of metal × 100) is, for example, 20% or more, preferably 25% or more, and for example, 90% or less, preferably 80% or less.

[0160] If the ratio of the number of moles of manganese in manganese oxide to the total number of moles of metal in the sulfur oxide adsorption component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Mn / total number of moles of metal × 100) is within the above range, it exhibits high sulfur oxide adsorption properties in a relatively high-temperature environment.

[0161] The ratio of the number of moles of iron in iron oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Fe / total number of moles of metal × 100) is, for example, 1% to 80%, preferably 5% to 75%.

[0162] The ratio of the number of moles of iron in iron oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (number of moles of Fe / total number of moles of metal × 100) is, for example, 1% or more, preferably 5% or more, and for example, 80% or less, preferably 75% or less.

[0163] The ratio of the number of moles of copper in copper oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Cu / total number of moles of metal × 100) is, for example, 1% to 50%, preferably 5% to 40%.

[0164] The ratio of the number of moles of copper in copper oxide to the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (total number of moles of metal in the metal oxide if it is a metal oxide) (moles of Cu / total number of moles of metal × 100) is, for example, 1% or more, preferably 5% or more, and for example, 50% or less, preferably 40% or less.

[0165] Furthermore, the total number of moles of metal in the sulfur oxide adsorbent component of the first modified example (or, in the case of a metal oxide, the total number of moles of metal in the metal oxide) is the total number of moles of metal in the manganese oxide, iron oxide, and copper oxide contained in the sulfur oxide adsorbent component of the first modified example; in other words, it is the total number of moles of manganese, iron, and copper.

[0166] The ratio of manganese content to the total amount of sulfur oxide adsorbing components in the first modified example (= manganese content (moles) / total amount of sulfur oxide adsorbing components in the first modified example (total moles) × 100) is, for example, 30 mol% or more, preferably 35 mol% or more, more preferably 40 mol% or more, and 90 mol% or less, preferably 85 mol or less.

[0167] The ratio of iron oxide content to the total amount of sulfur oxide adsorbing components in the first modified example (= iron oxide content (moles) / total amount of sulfur oxide adsorbing components in the first modified example (total moles) × 100) is, for example, 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and also, for example, 50 mol% or less, preferably 45 mol% or less, more preferably 40 mol% or less.

[0168] The content ratio of copper oxide to the total amount of sulfur oxide adsorbing components in the first modified example (= copper oxide content (moles) / total amount of sulfur oxide adsorbing components in the first modified example (total moles) × 100) is, for example, 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, and also, for example, 50 mol% or less, preferably 45 mol% or less, more preferably 40 mol% or less.

[0169] [Second Modification] In one embodiment of the sulfur oxide adsorbent described above, a flat and / or corrugated inorganic fiber sheet is used as the carrier on which the sulfur oxide adsorbent component and the inorganic binder are supported, but the invention is not limited thereto. Specifically, other carriers commonly used in sulfur oxide adsorbents may be used as the carrier on which the sulfur oxide adsorbent component and the inorganic binder are supported. Examples of other carriers include monolithic substrates having a cross-sectional network structure (honeycomb structure).

[0170] Examples of materials for the monolithic substrate include ceramics, cordierite, silicon carbide, silica, alumina, mullite, ceria, zirconia, their composite oxides, their solid solutions, and mixtures thereof.

[0171] The shape of the monolithic substrate is not particularly limited as long as it has a cross-sectional network structure (honeycomb structure), and examples include columnar bodies and block bodies.

[0172] 2. Exhaust Gas Treatment System An embodiment of the exhaust gas treatment system 1 of the present invention will be described with reference to Figures 1 and 2.

[0173] The exhaust gas treatment system 1 treats exhaust gas containing sulfur oxides emitted from the internal combustion engine. The internal combustion engine and the exhaust gas containing sulfur oxides will be described in more detail later.

[0174] In the following explanation, the upstream and downstream sides refer to the upstream and downstream sides in the direction of exhaust gas flow.

[0175] As shown in Figure 1, the exhaust gas treatment system 1 of this embodiment comprises an exhaust passage 2, a sulfur oxide adsorption unit 10, and an exhaust gas treatment unit 20. Specifically, it comprises an exhaust passage 2, a sulfur oxide adsorption unit 10 interposed in the exhaust passage 2 and having the above-mentioned sulfur oxide adsorbent 12, and an exhaust gas treatment unit 20 interposed in the exhaust passage 2, positioned downstream of the sulfur oxide adsorption unit 10, and having a catalyst (exhaust gas treatment catalyst) for treating harmful substances in the exhaust gas.

[0176] 2.1. Exhaust Passage The upstream end (inlet) of the exhaust passage 2 is connected to the exhaust outlet for exhaust gas discharged from the internal combustion engine. The exhaust gas discharged from the internal combustion engine flows through the exhaust passage 2. The downstream end of the exhaust passage 2 is open to the outside air or connected to a known aftertreatment device.

[0177] 2.2. Sulfur Oxide Adsorption Section The sulfur oxide adsorption section 10 is interposed in the exhaust passage 2 and has the sulfur oxide adsorbent 12 described above. As the exhaust gas passes through the sulfur oxide adsorption section 10, at least a portion of the sulfur oxides in the exhaust gas are adsorbed by the sulfur oxide adsorbent 12. The sulfur oxide adsorption section 10 is also located upstream of the exhaust gas processing section 20.

[0178] As shown in Figure 2, the sulfur oxide adsorption unit 10 includes, for example, a sulfur oxide adsorbent unit 11 comprising a casing 13 and a sulfur oxide adsorbent 12 filled inside the casing 13.

[0179] The shape of the casing 13 is not particularly limited, but examples include a rectangular tube shape and a cylindrical shape extending in the direction of exhaust gas flow. Preferably, a rectangular tube shape extending in the direction of exhaust gas flow is used. Specifically, the casing 13 can consist of a casing body with a substantially U-shape in cross-section and a flat plate-shaped cover that covers its opening, a casing body consisting only of a substantially square-shaped cross-section, and a casing body with a substantially L-shape in cross-section and a cover with a substantially inverted L-shape in cross-section that fits thereto.

[0180] The dimensions of the casing 13 are adjusted as appropriate according to the exhaust gas flow rate and other factors. Specifically, the length of the casing 13 in the exhaust gas flow direction (first direction) and the width direction (second direction) are not particularly limited as long as they can accommodate the sulfur oxide adsorbent 12. Also, the length of the casing 13 in the height direction (thickness direction) is not particularly limited as long as an appropriate number of layers of sulfur oxide adsorbent 12 can be secured.

[0181] An inorganic fiber blanket 14 may be laid over the entire inner surface of the casing 13. By laying an inorganic fiber blanket 14 on the inner surface of the casing 13, vibrations can be suppressed. Examples of inorganic fibers in the inorganic fiber blanket 14 include ceramic fibers, glass fibers, silica sol fibers, alumina fibers, and rock wool. Ceramic fibers are preferred.

[0182] In the sulfur oxide adsorbent unit 11, the sulfur oxide adsorbent 12 is packed inside the casing 13 in a direction perpendicular to the exhaust gas flow direction. Specifically, in the sulfur oxide adsorbent unit 11, flat plate-shaped sulfur oxide adsorbent 12 and corrugated plate-shaped sulfur oxide adsorbent 12 are stacked alternately inside the casing 13 without being bonded together. This stacking arrangement causes the sulfur oxide adsorbent 12 to form a cross-sectional network structure (honeycomb structure).

[0183] The sulfur oxide adsorbent unit 11 of this embodiment can be manufactured by alternately arranging flat sulfur oxide adsorbents 12 and corrugated sulfur oxide adsorbents 12 inside a casing 13 on which an inorganic fiber blanket 14 is laid over the entire inner surface.

[0184] When using the second modified sulfur oxide adsorbent 12, although not shown in the figure, it may be filled directly into the casing 13 without being laminated, or it may not be filled into the casing 13 at all.

[0185] Furthermore, the sulfur oxide adsorption section 10 preferably comprises a plurality of sulfur oxide adsorbent units 11. The number of sulfur oxide adsorbent units 11 in the sulfur oxide adsorption section 10 is not particularly limited and can be adjusted as appropriate depending on the installation space of the exhaust gas treatment system 1.

[0186] In this embodiment, the sulfur oxide adsorption unit 10 comprises a plurality of sulfur oxide adsorbent units 11 arranged in a direction perpendicular to the flow direction of the exhaust gas.

[0187] 2.3. Exhaust Gas Treatment Unit The exhaust gas treatment unit 20 is interposed in the exhaust passage 2 and has a catalyst (exhaust gas treatment catalyst) for treating harmful substances in the exhaust gas. When the exhaust gas passes through the exhaust gas treatment unit 20, the harmful substances in the exhaust gas are treated. Further, the exhaust gas treatment unit 20 is disposed on the downstream side of the sulfur oxide adsorption unit 10.

[0188] If the exhaust gas treatment unit 20 is disposed on the downstream side of the sulfur oxide adsorption unit 10, the inflow of sulfur oxides into the exhaust gas treatment unit 20 can be reduced. As a result, the performance degradation of the exhaust gas treatment catalyst described below due to sulfur oxides is suppressed, and the exhaust gas can be efficiently treated.

[0189] Note that treating the exhaust gas means, for example, treating harmful substances in the exhaust gas, and more specifically, decomposing harmful substances in the exhaust gas by an oxidation reaction, a reduction reaction, or the like.

[0190] The exhaust gas treatment unit 20 has an exhaust gas treatment catalyst. The exhaust gas treatment catalyst is not particularly limited as long as it is a catalyst for treating harmful substances in the exhaust gas, and is appropriately selected according to the composition of the exhaust gas. Examples of the exhaust gas treatment catalyst include a denitration catalyst (nitrogen oxide reduction catalyst), an ammonia decomposition catalyst, an N ２ O decomposition catalyst (nitrous oxide decomposition catalyst), and a methane oxidation catalyst. In other words, the exhaust gas treatment unit 20 has at least one selected from the group consisting of a denitration catalyst (nitrogen oxide reduction catalyst), an ammonia decomposition catalyst, an N ２ O decomposition catalyst (nitrous oxide decomposition catalyst), and a methane oxidation catalyst.

[0191] The methane oxidation catalyst is not particularly limited as long as it is a catalyst for oxidizing methane in the exhaust gas. The methane oxidation catalyst oxidizes methane at a temperature of 350 °C or higher.

[0192] The ammonia decomposition catalyst is not particularly limited as long as it is a catalyst that decomposes ammonia in exhaust gas. The nitrous oxide decomposition catalyst is not particularly limited as long as it is a catalyst that decomposes nitrous oxide in exhaust gas. The nitrogen oxide reduction catalyst (denitrification catalyst) is not particularly limited as long as it is a catalyst that reduces nitrogen oxides in exhaust gas. Examples of ammonia decomposition catalysts, nitrous oxide decomposition catalysts, and nitrogen oxide reduction catalysts (denitrification catalysts) include those described in Japanese Patent Application Publication No. 2024-61420.

[0193] Furthermore, the exhaust gas treatment catalyst may be any of the above-mentioned exhaust gas treatment catalysts used as is, or the active components described in the above publications may be supported on an inorganic fiber sheet using the method described in Japanese Patent Application Publication No. 2014-117649.

[0194] 2.4. Other Components The exhaust gas treatment system 1, although not shown in the figures, may further include a concentration sensor and a control unit, depending on the application.

[0195] [Concentration Sensor] Examples of concentration sensors include non-contact gas concentration meters that detect sulfur oxide concentration or oxygen concentration in exhaust gas. The placement of the concentration sensor is not particularly limited. The concentration sensor may be placed in the exhaust passage 2 upstream of the sulfur oxide adsorption unit 10, or in the exhaust passage 2 downstream of the sulfur oxide adsorption unit 10. The concentration sensor may also be electrically connected to a control unit, which will be described later.

[0196] When detecting sulfur oxide concentration using a concentration sensor, the sulfur oxide adsorption capacity of the sulfur oxide adsorption section 10 can be confirmed over time. If the sulfur oxide adsorption capacity of the sulfur oxide adsorption section 10 has decreased, as will be described in detail later, the sulfur oxide adsorption capacity of the sulfur oxide adsorption section 10 can be restored by heating the sulfur oxide adsorption section 10 to a high temperature to desorb the sulfur oxides adsorbed on the sulfur oxide adsorbent 12.

[0197] Furthermore, when oxygen concentration is detected by a concentration sensor, the control unit can appropriately change the combustion conditions in the internal combustion engine.

[0198] [Control Unit] The control unit is a unit that performs electrical control in the exhaust gas treatment system 1. The control unit consists of a microcomputer equipped with an arithmetic processing unit (CPU) and a memory unit. The control unit controls the exhaust gas treatment system 1 based on a control program stored in the memory unit.

[0199] Furthermore, the control unit is electrically connected to the concentration sensor, as described above.

[0200] The control unit can appropriately adjust the operation of the exhaust gas treatment system 1 based on the sulfur oxide concentration or oxygen concentration detected by the concentration sensor.

[0201] 2.5. Modified Exhaust Gas Treatment System In the modified examples, the same reference numerals are used for components and processes as in the above embodiment of the exhaust gas treatment system, and their detailed descriptions are omitted. Furthermore, the modified examples can achieve the same effects and functions as the above embodiment of the exhaust gas treatment system, unless otherwise specified. Moreover, the above embodiment and modified examples of the exhaust gas treatment system can be combined as appropriate.

[0202] [First Modified Example] The exhaust gas treatment system 1 described above includes only one exhaust gas processing unit 20, but is not limited thereto.

[0203] Specifically, the exhaust gas treatment system 1 may include a plurality of exhaust gas treatment units 20. Each of the plurality of exhaust gas treatment units 20 may be equipped with a different exhaust gas treatment catalyst.

[0204] As an example of a first modified form of the exhaust gas treatment system 1, although not shown, it includes, for example, a sulfur oxide adsorption unit 10 and an exhaust gas processing unit located downstream of the sulfur oxide adsorption unit 10, wherein the exhaust gas processing unit comprises a first exhaust gas processing unit, a second exhaust gas processing unit, and a third exhaust gas processing unit. The arrangement of the first exhaust gas processing unit, the second exhaust gas processing unit, and the third exhaust gas processing unit is not particularly limited.

[0205] The first exhaust gas treatment unit has, for example, an ammonia decomposition catalyst. The second exhaust gas treatment unit has, for example, a nitrous oxide decomposition catalyst. The third exhaust gas treatment unit has, for example, a denitrification catalyst.

[0206] [Second Modification] In the exhaust gas treatment system 1 described above, the exhaust passage 2 is a passage without branching, but is not limited to this.

[0207] Specifically, the exhaust passage 2 may have branches.

[0208] In the exhaust gas treatment method described later, when desorbing sulfur oxides from the sulfur oxide adsorbent, the exhaust passage 2 branches downstream of the sulfur oxide adsorption section 10 and upstream of the exhaust gas treatment section 20, allowing the desorbed sulfur oxides to be recovered without coming into contact with the exhaust gas treatment section 20.

[0209] 3. Method for adsorption and desorption of sulfur oxides Next, a method for adsorption and desorption of sulfur oxides using the above-mentioned sulfur oxide adsorbent will be explained.

[0210] The sulfur oxide adsorption and desorption method involves bringing exhaust gas containing sulfur oxides, emitted from an internal combustion engine, into contact with a sulfur oxide adsorbent to adsorb the sulfur oxides. When the sulfur oxide adsorption capacity of the sulfur oxide adsorbent decreases, the sulfur oxides are desorbed from the sulfur oxide adsorbent.

[0211] Exhaust gases include, for example, exhaust gases emitted from combustion devices that use LNG (liquefied natural gas) fuel, ammonia fuel, or a mixture of fossil fuels (e.g., gasoline, heavy oil) with ammonia fuel. Examples of such combustion devices include internal combustion engines such as land-based engines and marine engines.

[0212] The exhaust gas emitted from the above-mentioned internal combustion engine may contain, in addition to sulfur oxides, hydrocarbons (e.g., methane), nitrous oxide, nitrogen oxides, and ammonia. ２ H ２ O, and N ２ It may include.

[0213] Methods for adsorption and desorption of sulfur oxides include contacting exhaust gas with a sulfur oxide adsorbent to adsorb sulfur oxides, and desorbing sulfur oxides from the sulfur oxide adsorbent.

[0214] 3.1. Method for Adsorbing Sulfur Oxides In the method for adsorbing sulfur oxides, exhaust gas containing sulfur oxides is brought into contact with the sulfur oxide adsorbent described above. Specifically, the exhaust gas containing sulfur oxides passes through the gaps in the cross-sectional network structure of the sulfur oxide adsorbent 12, bringing the sulfur oxide adsorbent 12 into contact with the exhaust gas containing sulfur oxides, and adsorbing the sulfur oxides. The exhaust gas is then discharged. The discharged exhaust gas has a reduced amount of sulfur oxides compared to the exhaust gas before contact with the sulfur oxide adsorbent.

[0215] The concentration of sulfur oxides in the exhaust gas before contact with the sulfur oxide adsorbent is not particularly limited, and is, for example, 0.01 ppm or more, preferably 0.1 ppm or more, and also, for example, 100 ppm or less, preferably 10 ppm or less.

[0216] The exhaust gas flow rate is not particularly limited.

[0217] The temperature of the exhaust gas (the temperature of the exhaust gas when it comes into contact with the sulfur oxide adsorbent) is, for example, 300°C or higher, preferably 350°C or higher, and for example, 600°C or lower, preferably 550°C or lower, and more preferably 500°C or lower. In other words, the sulfur oxide adsorbent adsorbs sulfur oxides at temperatures of, for example, 300°C or higher, preferably 350°C or higher, and for example, 600°C or lower, preferably 550°C or lower, and more preferably 500°C or lower.

[0218] In other words, the sulfur oxide adsorbent described above has high sulfur oxide adsorption capacity even in relatively high-temperature environments as described above.

[0219] The sulfur oxide adsorption rate (after 4 hours) at 400°C for the sulfur oxide adsorbent is, for example, 85% or more, preferably 88% or more, and more preferably 90% or more.

[0220] The sulfur oxide adsorption rate (after 4 hours) at 400°C in a sulfur oxide adsorbent can be measured by the method described in the examples. Specifically, it can be calculated based on the amount of sulfur oxides in the gas before contact with the sulfur oxide adsorbent and the amount of sulfur oxides in the gas after contact with the sulfur oxide adsorbent. Specifically, it can be calculated using the following formula: Sulfur oxide adsorption rate (%) = ((Amount of sulfur oxides in the gas before contact with the sulfur oxide adsorbent - Amount of sulfur oxides in the gas after contact with the sulfur oxide adsorbent) / Amount of sulfur oxides in the gas before contact with the sulfur oxide adsorbent) × 100

[0221] The sulfur oxide adsorption rate (after 15 hours) at 400°C for the sulfur oxide adsorbent is, for example, 80% or more, preferably 83% or more, and more preferably 85% or more.

[0222] Furthermore, the sulfur oxide adsorption rate (after 15 hours) of the sulfur oxide adsorbent at 400°C can be measured by the method described in the examples.

[0223] 3.2. Method for Desorbing Sulfur Oxides In a sulfur oxide adsorbent, when the sulfur oxide adsorption capacity decreases, the sulfur oxide adsorbent is heated to desorb the sulfur oxides adsorbed on it.

[0224] The heating temperature for desorbing sulfur oxides from the sulfur oxide adsorbent is, for example, 650°C or higher, preferably 680°C or higher, and also, for example, 1000°C or lower. In other words, the sulfur oxide adsorbent desorbs sulfur oxides at, for example, 650°C or higher, preferably 680°C or higher.

[0225] In sulfur oxide adsorbents, removing sulfur oxides restores their sulfur oxide adsorption capacity.

[0226] (Effects) The sulfur oxide adsorption component of the present invention contains manganese oxide, and the crystal structure of the manganese oxide is tetragonal and / or hexagonal. Therefore, it has high sulfur oxide adsorption properties in relatively high-temperature environments.

[0227] The sulfur oxide adsorbent of the present invention comprises the above-mentioned sulfur oxide adsorbent component, an inorganic binder, and a carrier supporting the sulfur oxide adsorbent component and the inorganic binder. Therefore, the surface area of ​​the above-mentioned sulfur oxide adsorbent component in contact with exhaust gas can be increased. As a result, sulfur oxides can be adsorbed more efficiently in relatively high-temperature environments.

[0228] The present invention provides a method for adsorbing and desorbing sulfur oxides using the above-described sulfur oxide adsorbent, which adsorbs sulfur oxides at temperatures between 300°C and 600°C. Therefore, it is suitable for adsorbing sulfur oxides in relatively high-temperature environments.

[0229] The present invention provides a method for adsorbing and desorbing sulfur oxides using the above-described sulfur oxide adsorbent, which desorbs sulfur oxides at temperatures of 680°C or higher. Therefore, it is possible to regenerate the sulfur oxide adsorbent in higher temperature environments.

[0230] The exhaust gas treatment system of the present invention is an exhaust gas treatment system that treats exhaust gas discharged from an internal combustion engine and containing sulfur oxides, and comprises a sulfur oxide adsorption section having the above-mentioned sulfur oxide adsorbent, and a denitrification catalyst, ammonia decomposition catalyst, and N2, which are arranged downstream of the sulfur oxide adsorption section. ２ The system includes an exhaust gas treatment section having at least one selected from the group consisting of an oxygen decomposition catalyst and a methane oxidation catalyst. Even in relatively high-temperature environments, the sulfur oxide adsorption section has high sulfur oxide adsorption capacity, thereby suppressing the performance degradation of the catalyst in the exhaust gas treatment catalyst section and enabling efficient exhaust gas treatment.

[0231] The present invention will be further described below with reference to examples and comparative examples. However, the present invention is not limited in any way to the examples and comparative examples. Furthermore, specific numerical values ​​such as blending ratios (content ratios), physical properties, and parameters used in the following description may be replaced with the upper limits (numbers defined as "less than or equal to" or "less than") or lower limits (numbers defined as "greater than or equal to" or "greater than") of the corresponding blending ratios (content ratios), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0232] Example 1 [Preparation of sulfur oxide adsorbent] Manganese oxide (MnO ２ ) powder (manufactured by Tosoh Corporation) and iron oxide (Fe ２ O ３ A slurry (solid content: 45-55% by mass) was prepared by mixing the sulfur oxide adsorbent component of the powder (manufactured by Toda Kogyo Co., Ltd.), silica sol (solid content: 20% by mass), and water, and stirring for 10 minutes. ２ ) powder and iron oxide (Fe ２ O ３ The powder was mixed so that Mn and Fe were in the molar ratio (Mn / Fe) shown in Table 1. The silica sol was mixed so that the silica sol (solid content) amounted to 10% by mass of the total amount of sulfur oxide adsorbent and silica sol (solid content). Table 1 also shows the percentage of moles of Mn relative to the total number of moles of metals (Mn and Fe) in the sulfur oxide adsorbent.

[0233] Next, the prepared slurry was uniformly applied to glass paper and dried at 110°C for 1 hour. When the dried glass paper was to be flat, a flat mold was used for drying. When the dried glass paper was to be corrugated, a jig was used to shape it into a corrugated sheet during drying. Then, the glass paper coated with the flat slurry and the glass paper coated with the corrugated slurry were alternately stacked in a metal casing and fired at 500°C for 2.5 minutes. In this way, the sulfur oxide adsorbent of Example 1 was prepared.

[0234] Examples 2-10 and Comparative Example 1 Manganese oxide (MnO) ２ ) powder and iron oxide (Fe ２ O ３ Except for changing the amount of powder used, the sulfur oxide adsorbents for Examples 2 to 10 and Comparative Example 1 were prepared in the same manner as in Example 1. In Example 10, iron oxide (Fe ２ O ３ ) Powder was not used. In other words, the sulfur oxide adsorbent component in Example 10 was manganese oxide (MnO ２ ) consists only of. Example 10 is manganese oxide (MnO２ Since it consists only of (MnO), the molar ratio (Mn / Fe) is "-" in Table 1. Also, Comparative Example 1 is manganese oxide (MnO ２ ) Powder was not used. In other words, the sulfur oxide adsorbing component in Comparative Example 1 was iron oxide (Fe ２ O ３ ) consists only of these. Table 2 also shows the percentage (%) of moles of Mn relative to the total number of moles of metals (Mn and Cu) in the sulfur oxide adsorbent component.

[0235] Example 11 [Preparation of sulfur oxide adsorbent] Manganese oxide (MnO ２ A slurry (solid content: 45-55% by mass) was prepared by mixing the sulfur oxide adsorbing components of (Tosoh Corporation) powder and copper oxide (CuO) powder (Nisshin Chemco Co., Ltd. or Furukawa Chemicals Co., Ltd.), silica sol (solid content: 20% by mass), and water, and stirring for 10 minutes. ２ The powder and copper oxide (CuO) powder were mixed in the molar ratio (Mn / Cu) shown in Table 2. The silica sol was also mixed so that the silica sol (solid content) constituted 10% by mass of the total amount of the sulfur oxide adsorbent and the silica sol (solid content).

[0236] Next, the prepared slurry was uniformly applied to glass paper and dried at 110°C for 1 hour. When the dried glass paper was to be flat, a flat mold was used for drying. When the dried glass paper was to be corrugated, a jig was used to shape it into a corrugated sheet during drying. Then, the glass paper coated with the flat slurry and the glass paper coated with the corrugated slurry were alternately stacked in a metal casing and fired at 500°C for 2.5 minutes. In this way, the sulfur oxide adsorbent of Example 11 was prepared.

[0237] Examples 12-15 Manganese oxide (MnO) is prepared to achieve the molar ratios shown in Table 2. ２ The sulfur oxide adsorbents of Examples 12 to 15 were prepared in the same manner as in Example 11, except that the proportions of the powder and copper oxide (CuO) powder were changed.

[0238] <Evaluation> [X-ray Diffraction Spectra] X-ray diffraction (XRD) analysis was performed on the sulfur oxide adsorbent components in the sulfur oxide adsorbent of Example 8 and the sulfur oxide adsorbent of Example 13. For the measurements, an X-ray diffractometer (Uitima IV, Rigaku) ​​and an X-ray detector (D / teX Ultra, Rigaku) ​​were used, and the crystal structure was analyzed by the Black-Brentano method. Analysis software (PDXL 2 (Version 2.7.2.0), Rigaku) ​​was used for the analysis. The measurement conditions are as shown below. Figure 3 shows the XRD spectrum of the sulfur oxide adsorbent components in the sulfur oxide adsorbent of Example 8, and Figure 4 shows the XRD spectrum of the sulfur oxide adsorbent components in the sulfur oxide adsorbent of Example 13. {Measurement Conditions} X-ray source: CuKα (λ = 1.54058 nm, Ni filter, applied power: 40 kV, 40 mA) Scanning range: 2θ = 10° to 90° Scanning speed: 5.0° / min Sampling width: 0.01° Divergence slit: 0.20 mm Divergence longitudinal limiting slit: 2 mm Scattering slit: 2° Receiving slit: 0.15 mm Offset angle: 0°

[0239] [X-ray Photoelectron Spectroscopy Spectra] X-ray photoelectron spectroscopy (XPS) analysis was performed on the sulfur oxide adsorbent components of the sulfur oxide adsorbents of Examples 1-9 and 11-15. An X-ray photoelectron spectrometer (JPS-9010 series, JEOL Ltd.) was used for the measurements. Analysis software (SPECSURF Analysis (Version 2.7.2.0), JEOL Ltd.) was used for the analysis. The measurement conditions are as shown below. Figure 5 shows the XPS spectra of the sulfur oxide adsorbent components of the sulfur oxide adsorbents of Examples 1-9, and Figure 6 shows the XPS spectra of the sulfur oxide adsorbent components of the sulfur oxide adsorbents of Examples 11-15. From Figure 5, peaks of tetravalent manganese (641.0 eV to 642.5 eV) and trivalent iron (709.9 eV to 711.6 eV) were detected in the sulfur oxide adsorbent components of the sulfur oxide adsorbents of Examples 1-9. As shown in Figure 6, in the sulfur oxide adsorbents of Examples 11 to 15, peaks for tetravalent manganese (641.0 eV to 642.5 eV) and divalent copper (933.0 eV to 933.6 eV) were detected in the sulfur oxide adsorbent components. Table 1 shows the peak intensity ratio (Mn / Fe) of tetravalent manganese to trivalent iron in the sulfur oxide adsorbent components of Examples 1 to 10 and Comparative Example 1, and Table 2 shows the peak intensity ratio (Mn / Cu) of tetravalent manganese to divalent copper in the sulfur oxide adsorbent components of Examples 11 to 15. Note that since Example 10 does not contain iron oxide, the peak intensity ratio (Mn / Fe) is "-", and since Comparative Example 1 does not contain manganese oxide, the peak intensity ratio (Mn / Fe) is 0. {Measurement conditions} X-ray source: MgKα (hν=1253.6eV) Charge correction: C １ｓ (284.6 eV) Step: 0.10 eV Dwell (read time): 100 ms Pass energy: 10 eV Scan method: narrow (cumulative count: 256 times)

[0240] [Sulfur Oxide Adsorption Rate] The sulfur oxide adsorbent of each example and / or comparative example was placed in the middle of the flow path of test gas 1 having the composition described below. Then, test gas 1 heated to 400°C was supplied from the inlet of the flow path at a flow rate of 4.210 NL / min. Subsequently, the concentration of sulfur oxides (sulfur dioxide) in test gas 1 after contact with the sulfur oxide adsorbent (the concentration of sulfur dioxide in test gas 1 discharged from the outlet of the flow path) was continuously measured for 4 hours and 15 hours from the start of supply. The sulfur dioxide adsorption rate ((amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent - amount of sulfur dioxide in test gas 1 after contact with sulfur oxide adsorbent) / (amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent) × 100 (%)) was calculated from the amount of sulfur dioxide in test gas 1 before contact with the sulfur oxide adsorbent (amount of sulfur dioxide in test gas 1 supplied) and the amount of sulfur oxides in test gas 1 after contact with the sulfur oxide adsorbent (amount of sulfur dioxide in discharged test gas 1). The amount of sulfur dioxide in the test gas was calculated from the test gas flow rate, the sulfur dioxide concentration in the test gas, and the test gas supply time. The results are shown in Tables 1 and 2 and Figures 7 and 8. Note that SO4 was used to quantify the sulfur dioxide concentration. ２ A meter (Model 43i-HL, manufactured by Nippon Thermo Co., Ltd.) was used. The measurement conditions are as follows: {Test gas 1 composition} SO ２ : 10 ppm CH ４ : 1000 ppm O ２ : 12% by volume H ２ O: 8% by volume {SO ２ Measurement conditions for the meter (Model 43i-HL, manufactured by Nippon Thermo Co., Ltd.): Measured component: SO2 (sulfur dioxide) Measurement method: ultraviolet fluorescence method (UVF method) Measurement range: 100 ppm

[0241] [Sulfur Oxide Desorption Test] The desorption temperature of the adsorbed sulfur oxides was evaluated for the sulfur oxide adsorbent of Example 8. Specifically, the sulfur oxide adsorbent of Example 8 was placed in the middle of the flow path of test gas 2, which had the following composition. Then, test gas 2 was supplied from the inlet of the flow path. The temperature of test gas 2 was raised from 400°C to 800°C at a rate of 5°C / min. After that, the sulfur oxides in test gas 2 after contact with the sulfur oxide adsorbent (the concentration of sulfur dioxide in test gas 2 discharged from the outlet of the flow path) were analyzed using thermal generated gas mass spectrometry (TPD / MS) (Microtrac-Bel catalyst analyzer BELCAT II and Microtrac-Bel online gas analyzer BELMASS). The peak intensity of the sulfur dioxide peak (m / z = 64) was measured. The results are shown in Figure 9. The measurement conditions for thermal generated gas mass spectrometry (TPD / MS) are shown below. {Test gas 2 composition} SO ２ : 100 ppm CH ４ : 1000 ppm O ２ : 12% by volume N ２ Balance {TPD / MS Measurement Conditions} Measurement Mode: Automatic Sequencing Measurement Sample: Example 8 Sample Amount: 300 mg Detector: Q-MASS MASS Setting: Detection m / z = 2, 15, 16, 17, 18, 32, 33, 34, 48, 64, 80, 96 TPD: CH ４ , O ２ , N ２ mixed gas (CH ４ :1,000ppm, O ２ : 20%, N ２ The temperature was increased from 400°C to 800°C at a rate of 5 K / min while a balance was circulated. After reaching 800°C, it was held at that temperature for 60 minutes.

[0242] [Temperature applicability of sulfur dioxide adsorbent] The sulfur oxide adsorbent of Example 8 was placed in the middle of the flow path of test gas 1 having the above composition. Then, test gas 1 heated to 300°C, 400°C, and 500°C were supplied from the inlet of the flow path at a flow rate of 4.210 NL / min-wet. Subsequently, the concentration of sulfur oxides (sulfur dioxide) in test gas 1 after contact with the sulfur oxide adsorbent (the concentration of sulfur dioxide in test gas 1 discharged from the outlet of the flow path) was continuously measured for 15 hours from the start of supply. The sulfur dioxide adsorption rate ((amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent - amount of sulfur dioxide in test gas 1 after contact with sulfur oxide adsorbent) / (amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent) × 100 (%)) was calculated from the amount of sulfur dioxide in test gas 1 before contact with the sulfur oxide adsorbent (amount of sulfur dioxide in test gas 1 supplied) and the amount of sulfur oxides in test gas 1 after contact with the sulfur oxide adsorbent (amount of sulfur dioxide in discharged test gas 1). The amount of sulfur dioxide in the test gas was calculated from the test gas flow rate, the sulfur dioxide concentration in the test gas, and the test gas supply time. The results are shown in Table 3. Note that SO4 was used to quantify the sulfur dioxide concentration. ２ A meter (Model 43i-HL, manufactured by Nippon Thermo Co., Ltd.) was used. The measurement conditions were the same as those for the evaluation of sulfur oxide adsorption described above.

[0243] [Sulfur dioxide adsorption based on manganese valency] The sulfur oxide adsorbent of Example 8 was placed in the middle of the flow path of test gas 1 having the above composition. Next, test gas 1 heated to 400°C was supplied from the inlet of the flow path at a flow rate of 4.210 NL / min-wet. Subsequently, the concentration of sulfur oxides (sulfur dioxide) in the test gas after contact with the sulfur oxide adsorbent (the concentration of sulfur dioxide in test gas 1 discharged from the outlet of the flow path) was measured 15 hours after the start of supply. The sulfur dioxide adsorption rate ((amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent - amount of sulfur dioxide in test gas 1 after contact with sulfur oxide adsorbent) / (amount of sulfur dioxide in test gas 1 before contact with sulfur oxide adsorbent) × 100 (%)) was calculated from the amount of sulfur dioxide in test gas 1 before contact with the sulfur oxide adsorbent (amount of sulfur dioxide in test gas 1 supplied) and the amount of sulfur oxides in test gas 1 after contact with the sulfur oxide adsorbent (amount of sulfur dioxide in discharged test gas 1). The amount of sulfur dioxide in the test gas was calculated from the test gas flow rate, the sulfur dioxide concentration in the test gas, and the test gas supply time. The results are shown in Table 4. Note that SO4 was used to quantify the sulfur dioxide concentration. ２ A meter (Model 43i-HL, manufactured by Nippon Thermo Co., Ltd.) was used. The measurement conditions were the same as those for the evaluation of sulfur oxide adsorption described above.

[0244] The sulfur oxide adsorbent of Example 8 was heated at 600°C for 5 minutes to change the valency of manganese. Specifically, MnO ２ However, Mn ２ O ３ It changed to this. Using the sulfur oxide adsorbent of Example 8 after heating, the sulfur dioxide adsorption rate was calculated using the same procedure as above. The results are shown in Table 4.

[0245]

[0246]

[0247]

[0248]

[0249] [Discussion] From Figure 3, the sulfur oxide adsorbent component of Example 8 is manganese oxide (MnO ２The peaks indicate that the crystal structure of ) is tetragonal, and iron oxide (Fe ２ O ３ A peak indicating that the crystal structure of ) is hexagonal was detected. However, no peak for a manganese-iron composite oxide was detected. Furthermore, from Figure 4, the sulfur oxide adsorbed component of Example 13 was manganese oxide (MnO ２ Peaks indicating a tetragonal crystal structure for () and a monoclinic crystal structure for copper oxide (CuO) were detected. No peaks for the manganese-copper composite oxide were detected.

[0250] As shown in Figure 7, the sulfur dioxide adsorption rate after 4 hours was higher for the sulfur oxide adsorbents of Examples 1 to 10 than for the sulfur oxide adsorbent of Comparative Example 1. In particular, the sulfur dioxide adsorption rate after 4 hours was high for the sulfur oxide adsorbents of Examples 3 to 8. Furthermore, the sulfur dioxide adsorption rate after 15 hours was higher for the sulfur oxide adsorbents of Examples 1 to 10 than for the sulfur oxide adsorbent of Comparative Example 1. In particular, the sulfur dioxide adsorption rate after 15 hours was high for the sulfur oxide adsorbents of Examples 4 to 8.

[0251] Figure 9 shows that sulfur dioxide was not desorbed from the sulfur oxide adsorbent of Example 8 at temperatures below 600°C. Furthermore, sulfur dioxide was desorbed from the sulfur oxide adsorbent of Example 8 at temperatures above 680°C. This suggests that such a sulfur oxide adsorbent can be used at temperatures below 600°C. Moreover, it suggests that such a sulfur oxide adsorbent is regenerative at temperatures above 680°C.

[0252] Table 3 shows that the above sulfur oxide adsorbent exhibits a high sulfur oxide adsorption rate in the high-temperature range of 300°C to 500°C.

[0253] Table 4 shows that the above sulfur oxide adsorbent maintains a high sulfur oxide adsorption rate even when the valency of manganese changes due to heating, specifically when the valency of manganese changes from tetravalent to trivalent. In other words, it is suggested that the above sulfur oxide adsorbent can maintain a high sulfur oxide adsorption capacity even after desorption and regeneration of sulfur dioxide.

[0254] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims below.

[0255] The sulfur oxide adsorption component of the present invention is suitably used as a sulfur oxide adsorbent for adsorption of sulfur oxides contained in exhaust gas discharged from LNG-fueled ships, and for adsorption of sulfur oxides contained in gases generated in processes such as gas-phase reactions in chemical plants. Furthermore, the sulfur oxide adsorbent of the present invention is suitably used for adsorption of sulfur oxides contained in exhaust gas discharged from LNG-fueled ships, and for adsorption of sulfur oxides contained in gases generated in processes such as gas-phase reactions in chemical plants. In addition, the sulfur oxide adsorption and desorption method of the present invention is suitable for adsorption and desorption of sulfur oxides in exhaust gas containing sulfur oxides discharged from internal combustion engines. Furthermore, the exhaust gas treatment system of the present invention is suitable for treating exhaust gas containing sulfur oxides discharged from internal combustion engines.

[0256] 1. Exhaust gas treatment system 2. Exhaust passage 10. Sulfur oxide adsorption section 11. Sulfur oxide adsorbent unit 12. Sulfur oxide adsorbent 13. Casing 14. Inorganic fiber blanket 20. Exhaust gas treatment section

Claims

1. A sulfur oxide adsorbent component containing manganese oxide, wherein the crystalline structure of the manganese oxide is tetragonal and / or hexagonal.

2. The sulfur oxide adsorbent component according to claim 1, wherein the sulfur oxide adsorbent further contains iron oxide, and the molar ratio of manganese in manganese oxide to iron in the iron oxide (Mn / Fe) is 0.21 or more and 4.50 or less.

3. The sulfur oxide adsorbent component according to claim 2, wherein the molar ratio (Mn / Fe) of manganese in manganese oxide to iron in iron oxide is 0.26 or more and 2.84 or less.

4. The manganese oxide is trivalent manganese oxide (Mn ２ O ３ ) and / or tetravalent manganese oxide (MnO ２ ) consists of, and the iron oxide is trivalent iron oxide (Fe ２ O ３ The sulfur oxide adsorbent component according to claim 2, wherein the iron oxide has a hexagonal crystal structure.

5. The sulfur oxide adsorbent component according to claim 1, wherein the sulfur oxide adsorbent component further contains copper oxide, and the molar ratio of manganese in manganese oxide to copper in the copper oxide (Mn / Cu) is 1.00 or more and 9.00 or less.

6. The sulfur oxide adsorbent component according to claim 5, wherein the molar ratio (Mn / Cu) of manganese in manganese oxide to copper in copper oxide is 1.22 or more and 5.67 or less.

7. The manganese oxide is trivalent manganese oxide (Mn ２ O ３ ) and / or tetravalent manganese oxide (MnO ２ The sulfur oxide adsorbent component according to claim 5, wherein the copper oxide consists of divalent copper oxide (CuO), and the crystal structure of the copper oxide is monoclinic.

8. A sulfur oxide adsorbent comprising a sulfur oxide adsorbent component according to any one of claims 1 to 7, an inorganic binder, and a carrier supporting the sulfur oxide adsorbent component and the inorganic binder.

9. A method for adsorbing and desorbing sulfur oxides using the sulfur oxide adsorbent described in claim 8, wherein the sulfur oxide adsorbent adsorbs sulfur oxides at a temperature of 300°C or higher and 600°C or lower.

10. A method for adsorbing and desorbing sulfur oxides using the sulfur oxide adsorbent described in claim 8, wherein the sulfur oxide adsorbent desorbs sulfur oxides at a temperature of 680°C or higher.

11. An exhaust gas treatment system for treating exhaust gas discharged from an internal combustion engine and containing sulfur oxides, the system comprising: a sulfur oxide adsorbing section having the sulfur oxide adsorbent according to claim 8; and an exhaust gas treatment section disposed downstream of the sulfur oxide adsorbing section and having at least one selected from the group consisting of a denitration catalyst, an ammonia decomposition catalyst, an N ２ O decomposition catalyst, and a methane oxidation catalyst.

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