Methane oxidation reaction catalyst having sulfur resistance and methane oxidation method using same

Abstract

The present invention relates to a catalyst for a methane oxidation reaction and a methane oxidation method using same, and more particularly, to a catalyst for a methane oxidation reaction, the catalyst being capable of efficiently oxidizing methane for a long period of time even in the presence of a large amount of moisture and sulfur oxides, and a methane oxidation method using same.

Description

Catalyst for methane oxidation reaction having sulfur tolerance and methane oxidation method using the same

[0001] The present invention relates to a catalyst for methane oxidation reaction and a methane oxidation method using the same, and more particularly, to a catalyst for methane oxidation reaction capable of efficiently oxidizing methane in LNG fuel exhaust gas for a long period of time even in the presence of a large amount of moisture and sulfur oxides, and a methane oxidation method using the same.

[0002] Oil, a widely used energy source worldwide, is gradually depleting, and political instability in the Middle East, the world's largest oil producer, is expected to lead to continued high oil prices. In contrast, natural gas, primarily composed of methane, boasts reserves approximately 40% more abundant than oil, making it a cheap and abundant energy source found worldwide. Natural gas is currently widely used as a fuel for combined heat and power plants and public transportation.

[0003] However, methane, emitted from incomplete combustion of natural gas, is a major contributor to global warming. Because of its long lifespan, methane can have a greater negative impact on global warming than carbon dioxide. Most industrialized countries have been working to manage and remove methane, including by enforcing methane emission regulations for natural gas vehicles, particularly heavy-duty vehicles, since Euro III.

[0004] Among VOCs, methane possesses a highly stable CH bond, making it difficult to completely oxidize at low temperatures below 500°C. Consequently, technologies for removing methane with low energy input are in demand. Among these, catalytic methane oxidation is receiving the most attention and is being extensively studied.

[0005] The catalysts used in this methane oxidation reaction are mainly catalysts that support platinum group noble metals (Pt, Pd, Au, etc.) on carriers that exhibit stable physicochemical properties at high temperatures, such as aluminum oxide (Al2O3), zirconium oxide (ZrO2), titanium oxide (TiO2), and silicon oxide (SiO2) (Patent Documents 0001 to 0003).

[0006] However, its use in commercial processes for methane treatment is limited due to the reduced catalytic activity caused by the large amounts of sulfur oxides (SO2, SOx) and moisture emitted in the process exhaust gas. For this reason, the development of a catalyst capable of efficiently removing methane in the presence of sulfur oxides and moisture is essential.

[0007] In this regard, Japanese Patent No. 5865110 proposes a methane oxidation catalyst in which platinum, ruthenium, and chlorine are supported on a zirconium oxide support to oxidize and remove methane in exhaust gas containing sulfur dioxide. However, since the sulfur dioxide poisoning condition is SO23 ppm and the catalyst poisoning evaluation is conducted for a very short period of time of 60 hours, it is difficult to say that the catalyst has sulfur tolerance. In addition, US Patent Publication No. 2022-0268191 proposes a methane oxidation catalyst in which platinum and ruthenium are supported on polycrystalline zirconia. However, this too is difficult to say that the catalyst has sulfur tolerance because the sulfur dioxide poisoning condition is SO25 ppm and the poisoning evaluation is conducted at a low concentration.

[0008] Therefore, there is a need to develop a catalyst that can oxidize methane with excellent durability and thermal stability for a long time even in a high-temperature environment exposed to a large amount of moisture and sulfur oxides.

[0009] [Prior Art Literature]

[0010] [Patent Document]

[0011] (Patent Document 0001) Korean Patent No. 10-1909303 (Published: December 5, 2013)

[0012] (Patent Document 0002) Korean Patent Publication No. 10-2016-0112179 (Published: September 28, 2016)

[0013] (Patent Document 0003) Korean Patent No. 10-1598390 (Published: December 30, 2015)

[0014] (Patent Document 0004) Japanese Patent No. 5865110 (Published: September 2, 2013)

[0015] (Patent Document 0005) U.S. Patent Publication No. 2022-0268191 (August 25, 2022)

[0016] The main purpose of the present invention is to solve the above-mentioned problems, and to provide a catalyst for methane oxidation reaction and a method for manufacturing the same, which can efficiently oxidize methane for a long time with stable high catalytic activity even in a high-temperature environment exposed to a large amount of moisture and sulfur oxides.

[0017] In addition, an object of the present invention is to provide a methane oxidation method capable of efficiently oxidizing methane in a high-temperature environment exposed to a large amount of moisture and sulfur oxides using the methane oxidation reaction catalyst.

[0018] In order to achieve the above object, one embodiment of the present invention provides a catalyst for a methane oxidation reaction that oxidizes methane in a mixed gas containing methane, sulfur oxide, and moisture, the catalyst comprising: a tin-containing metal oxide having a crystal size of 10 nm to 40 nm; and a catalytically active metal supported on the tin-containing metal oxide; wherein the catalytically active metal comprises ruthenium and platinum in a weight ratio of 0.1:1.0 to 5.0:1.0, and the weight ratio of the catalytically active metal and the tin-containing metal oxide is 1:50 to 1:300.

[0019] In a preferred embodiment of the present invention, the tin-containing metal oxide may be characterized by having a maximum peak at 640°C to 735°C when analyzed by H2-TPR (hydrogen thermodynamic reduction).

[0020] In a preferred embodiment of the present invention, the tin-containing metal oxide has a BET specific surface area of ​​5 m 2 / g ~ 40 m 2 It can be characterized by / g.

[0021] Another embodiment of the present invention provides a method for producing a catalyst for methane oxidation reaction that oxidizes methane in a mixed gas containing methane, sulfur oxide, and moisture, comprising the steps of: (a) supporting a catalytically active metal on a tin-containing metal oxide so that the weight ratio of the catalytically active metal and the tin-containing metal oxide in the produced catalyst is 1:50 to 1:300; and (b) drying and calcining the support on which the catalytically active metal is supported; wherein in step (a), the tin-containing metal oxide has a crystal size of 10 nm to 40 nm, the catalytically active metal includes ruthenium and platinum, and the ruthenium and platinum are supported on the tin-containing metal oxide in a weight ratio of 0.1:1.0 to 5.0:1.0 in the produced catalyst.

[0022] In another preferred embodiment of the present invention, the tin-containing metal oxide of step (a) may be characterized by having a maximum peak at 640°C to 735°C when analyzed by H2-TPR (hydrogen thermodynamic reduction).

[0023] In another preferred embodiment of the present invention, the tin-containing metal oxide of step (a) has a BET specific surface area of ​​5 m 2 / g ~ 40 m 2 It can be characterized by / g.

[0024] Another embodiment of the present invention provides a methane oxidation method characterized in that methane is oxidized in a mixed gas containing methane, sulfur oxide, and moisture in the presence of the above methane oxidation reaction catalyst.

[0025] In another preferred embodiment of the present invention, the oxidation may be performed at 400°C to 800°C.

[0026] The catalyst for methane oxidation reaction according to the present invention can stably maintain excellent catalytic activity for a long period of time even in an environment exposed to a large amount of moisture and sulfur oxides, and thus has the effect of usefully treating methane without the constraints of moisture and sulfur oxides in exhaust gases emitted from various processes requiring methane removal, especially power plants, burners, engines, etc. that use at least a portion of liquefied natural gas (LNG) as fuel.

[0027] Figure 1 is a graph showing the results of measuring the methane conversion rate according to the methane oxidation reaction time of the catalysts manufactured in Examples 1 to 8 of the present invention.

[0028] Figure 2 is a graph showing the results of measuring the deactivation rate of catalysts manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 of the present invention.

[0029] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0030] In describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description is omitted.

[0031] In the specification, when "includes," "has," and "consists of" are used, other parts may be added unless "only" is used. When a component is expressed in the singular, it includes cases where the plural is included unless there is a special explicit description.

[0032] Also, when describing a positional relationship, for example, when the positional relationship between two parts is described with '~on top', '~upper part', '~lower part', '~next to', etc., one or more other parts may be located between the two parts unless 'right away' or 'directly' is used. When describing a temporal relationship, for example, when the temporal chronological relationship is described with '~after', '~following', '~next to', '~before', etc., cases where they are not consecutive may also be included unless 'right away' or 'directly' is used.

[0033] The features of each of the various embodiments of the present invention can be partially or wholly combined or combined with each other, and various technical linkages and operations are possible, and each embodiment can be implemented independently of each other or implemented together in a related relationship.

[0034] In general, catalysts using precious metals are used to remove environmental pollutants contained in exhaust gases generated from automobiles and ships using natural gas engines. A representative example of such environmental pollutants is methane (CH4). Methane is a very stable substance, but it is difficult to process at low temperatures, and oxidation catalysts are used to remove methane at high temperatures. However, conventional methane oxidation catalysts are not suitable for high-temperature or high-pressure environments, especially in the presence of moisture (water vapor) and sulfur oxides (SO2, SO2). x) rapidly progresses in mixed gas conditions where methane oxidation catalysts coexist, thereby reducing the performance of the methane oxidation catalyst and reducing long-term stability, making it impossible to guarantee catalytic activity for the desired period of time. Therefore, high-performance and high-functionality catalyst and support material technologies are essential.

[0035] In order to solve such problems, the present invention confirmed that excellent catalytic activity can be stably maintained for a long period of time even in a high-temperature environment where water vapor (moisture) and sulfur oxide are present by supporting platinum and ruthenium as catalytically active metals on a tin-containing metal oxide under specific conditions, and thus led to the present invention.

[0036] A catalyst for methane oxidation according to the present invention may include a tin-containing metal oxide and a catalytically active metal on at least a portion of the surface of the tin-containing metal oxide.

[0037] The above tin-containing metal oxide is a catalyst carrier that supports a catalytically active metal, and may be a metal oxide containing tin element, and specifically, may be tin oxide (SnO2). The tin oxide (SnO2) may exhibit a methane conversion rate of 5% to 10% during a methane oxidation reaction even without a catalytically active metal such as a precious metal.

[0038] In addition, the tin-containing metal oxide has a crystal size of 10 nm to 40 nm as measured by XRD and a BET specific surface area of ​​5 m 2 / g ~ 40 m 2 / g, and it can be characterized by having a maximum peak at 640 ℃ to 735 ℃ when analyzed by H2-TPR (hydrogen thermodynamic reduction method).

[0039] The specific surface area, crystal size, and maximum peak temperature range measured by the hydrogen temperature reduction method of the tin-containing metal oxide are basically limited to the range of physical properties of the tin-containing metal oxide at which the methane oxidation reaction reaches its peak as a result of repeated research, and the inventors of the present invention were able to confirm that the methane oxidation reaction varies greatly based on the specific surface area, crystal size, and peak temperature range measured by the hydrogen temperature reduction method of the tin-containing metal oxide.

[0040] If the crystal size of the above tin-containing metal oxide is 10 nm to 40 nm and the BET specific surface area is 5 m 2 / g ~ 40 m 2 / g, it can stably maintain excellent catalytic activity for a long time even in an environment exposed to a large amount of moisture and sulfur oxides, whereas, if the crystal size of the tin-containing metal oxide is less than 10 nm, the initial methane conversion rate may be low and the durability to sulfur may be low due to the low crystal size of the tin-containing metal oxide, and if the crystal size of the tin-containing metal oxide exceeds 40 nm, the initial methane conversion rate may be low and the durability to sulfur may be low due to the large crystal size of the tin-containing metal oxide.

[0041] In addition, the specific surface area of ​​the tin-containing metal oxide is 5 m 2 / g, the catalytically active metal is not uniformly dispersed due to the low specific surface area of ​​the tin-containing metal oxide, but is supported on the tin-containing metal oxide in agglomerates, which may cause problems such as low initial methane conversion and low durability against sulfur, and 40 m 2 If it exceeds / g, the thermal stability of the catalyst and durability against sulfur may be reduced due to the high specific surface area of ​​the tin-containing metal oxide.

[0042] Here, the 'crystal size' of the tin-containing metal oxide is also referred to as the 'crystal grain size' and is a size calculated from the width of peaks typically observed in XRD measurements, and should be distinguished from the particle size or particle diameter obtained by SEM images. In addition, the specific surface area of ​​the tin-containing metal oxide can be measured using the conventional BET method, and a detailed description thereof will be omitted.

[0043] In addition, H2-TPR (hydrogen temperature-reduction) analysis is an analysis method for evaluating the reduction ability of a catalyst using hydrogen gas. H2-TPR evaluates the reduction degree of a tin-containing metal oxide by flowing gas over it and raising the temperature to the target temperature at a set temperature increase rate. At this time, when the tin-containing metal oxide is reduced by the reducing gas, a peak occurs, and the peak value indicates the point where hydrogen consumption is high at a specific temperature.

[0044] The tin-containing metal oxide of the present invention has a H2-TPR maximum peak value at 640°C to 735°C. When the H2-TPR maximum peak value of the tin-containing metal oxide is less than 640°C, the crystal size and specific surface area of ​​the tin-containing metal oxide are low, which may cause problems such as low initial methane conversion and low durability against sulfur. When the temperature exceeds 735°C, the crystal size and specific surface area of ​​the tin-containing metal oxide are large, which may cause problems such as low initial methane conversion and low durability against sulfur.

[0045] The specific surface area, crystal size, and maximum peak temperature range measured by the hydrogen temperature reduction method of tin-containing metal oxides can be controlled by adjusting various conditions such as the manufacturing conditions of tin-containing metal oxides, specifically, the calcination amount, calcination time, and calcination temperature.

[0046] The above tin-containing metal oxide can be manufactured without limitation by any method capable of manufacturing a metal oxide containing tin element, and the tin-containing metal oxide can be manufactured using a method known in the technical field to which the present invention pertains, such as a precipitation method, a sol-gel method, a co-precipitation method, or a hydrothermal synthesis method.

[0047] As an example, the production of a tin-containing metal oxide using a precipitation method can be performed by precipitating a tin precursor using a precipitating agent such as ammonium carbonate, ammonium bicarbonate, ammonia water, potassium hydroxide, sodium carbonate, sodium hydroxide, or sodium hydrogen carbonate, and then drying and calcining the precipitate to produce a tin-containing metal oxide. The tin precursor can be at least one selected from nitrates, sulfates, phosphoric acids, halogen salts, alkoxide salts, oxynitrates, hydrates, acetate salts, alkyl salts, and hydrates thereof containing tin element or ion, and preferably, a halogen salt hydrate can be used.

[0048] At this time, the calcination can be performed at 350°C to 950°C, preferably 400°C to 900°C, to control the specific surface area, crystal size, and maximum peak temperature range measured by the hydrogen temperature reduction method, and the calcination time can be adjusted according to the calcination amount and temperature, and can be performed for, for example, 2 hours to 10 hours.

[0049] Meanwhile, the catalytically active metal supported on the tin-containing metal oxide is a material that activates the methane oxidation reaction and may include ruthenium and platinum, and the ruthenium and platinum may be included in a weight ratio of 0.1:1.0 to 5.0:1.0, preferably in a weight ratio of 0.5:1.0 to 5.0:1.0, and more preferably in a weight ratio of 0.7:1.0 to 5.0:1.0.

[0050] If the weight ratio of ruthenium to platinum is less than 0.1, a problem of low durability against sulfur may occur due to the low ruthenium content, and if the weight ratio of ruthenium to platinum exceeds 5.0, a problem of low initial methane conversion rate and low durability against sulfur may occur due to the high ruthenium content.

[0051] In addition, the weight ratio of the catalytically active metal and the tin-containing metal oxide is 1:50 to 1:300, preferably 1:100 to 1:250. If the weight ratio of the tin-containing metal oxide to the catalytically active metal is less than 50, the catalytically active metals such as platinum and ruthenium may not be evenly supported on the tin-containing metal oxide, which may cause a problem in that the effect is reduced compared to the content of the catalytically active metal. If the weight ratio of the tin-containing metal oxide to the catalytically active metal exceeds 300, the content of the catalytically active metal may be too low, so that the effect as a catalyst on the oxidation reaction of methane may be minimal.

[0052] The catalyst for methane oxidation reaction according to the present invention has a deactivation rate of 10% or less calculated using the following mathematical formula 1, and thus, due to its low deactivation rate, the catalyst life can be improved even under harsh reaction conditions.

[0053] [Mathematical Formula 1]

[0054] Inactivation rate (%) = (C T0 -C T57 ) / (C T0 ) × 100

[0055] In the above mathematical formula 1, C T0 is the methane conversion rate measured at the initial time, and C T57is the methane conversion rate after 57 hours, and the methane conversion rate is calculated through the change in methane concentration by measuring the methane concentration before and after the methane oxidation reaction. At this time, the methane oxidation reaction may be an oxidation reaction of methane in a mixed gas containing 125 ppmv of sulfur dioxide, 10 vol% of H2O, and 2,000 ppmv of methane, and the reaction temperature of the methane oxidation reaction may be 500 ℃.

[0056] The method for manufacturing a catalyst for methane oxidation reaction in which the above catalytically active metal is supported on a tin-containing metal oxide can be applied without limitation as long as it is a method capable of supporting the catalytically active metal on a tin-containing metal oxide, and specifically, the catalytically active metal can be supported on a tin-containing metal oxide using a method known in the technical field to which the present invention pertains, such as an impregnation method, a co-precipitation method, a solid-phase support method, a vapor deposition method, a wash coating method, a sol-gel method, a hydrothermal synthesis method, etc.

[0057] In one embodiment, the impregnation-based support includes the steps of impregnating a tin-containing metal oxide with a catalytically active metal to support the catalytically active metal; and drying and calcining the tin-containing metal oxide on which the catalytically active metal is supported.

[0058] The above impregnation can be performed by dissolving a precursor of a catalytically active metal in a solvent, dividing it into several stages, and evenly dispersing the precursor of the catalytically active metal dissolved in the solvent on the catalyst support, and performing wet impregnation at 10°C to 200°C. The impregnation time can be applied without limitation as long as it can be sufficiently supported depending on the situation, and can be performed for, for example, 1 hour to 12 hours.

[0059] At this time, in the present invention, the precursor of the catalytically active metal may be at least one selected from nitrates, sulfates, phosphoric acids, halogen salts, alkoxide salts, oxynitrates, hydroxides, acetate salts, alkyl salts, and hydrates thereof, each containing the catalytically active metal, i.e., ruthenium and platinum elements, or ions, and preferably, a halogen salt hydrate may be used.

[0060] In addition, as a solvent capable of dissolving the precursor of the catalytically active metal, any known solvent capable of dissolving the catalytically active metal of the present invention can be used, and specifically, it can be a glycol solvent such as water, ethylene glycol, 1,2-propylene glycol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, diethylene glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, trimethylol propane, or an alcohol solvent such as methanol, ethanol, isopropyl alcohol (IPA), butanol, etc., and the solvent content can be used without limitation as long as it is an amount capable of uniformly dispersing the precursor of the catalytically active metal, and for example, it can be 100 to 500 parts by weight with respect to 100 parts by weight of the precursor of the catalytically active metal.

[0061] Next, the tin-containing metal oxide impregnated with the catalytically active metal can be dried and calcined by controlling the time and temperature according to conditions such as the amount of catalytically active metal supported, the size and amount of the tin-containing metal oxide, etc. For example, after drying at 10 ℃ to 120 ℃, it can be calcined at 400 ℃ to 900 ℃ for 3 to 12 hours. At this time, when the calcination temperature is less than 400 ℃, the initial methane conversion rate may be low and the durability to sulfur may be low due to the small crystal size and the large specific surface area, and when it exceeds 900 ℃, the initial methane conversion rate may be low and the durability to sulfur may be low due to the large crystal size and the small specific surface area.

[0062] In addition, it is desirable to manufacture by gradually increasing the temperature because rapid temperature changes during the firing process cause cracks and pores to be generated due to rapid evaporation and oxidation of the solvent, which significantly reduces the strength.

[0063] The catalyst for methane oxidation according to the present invention can efficiently oxidize methane with high catalytic activity for a long period of time, even in an environment without water vapor and / or sulfur oxides, as well as in a high-temperature environment exposed to a large amount of moisture and sulfur oxides.

[0064] A methane oxidation method according to one embodiment of the present invention oxidizes methane in a mixed gas containing methane, sulfur oxide, and moisture in the presence of the aforementioned methane oxidation reaction catalyst to produce water and carbon dioxide. At this time, the contents of moisture and sulfur oxide are not limited, but for example, moisture may be 20 vol% or less with respect to the total volume of the mixed gas, and sulfur oxide may be 500 ppmv or less.

[0065] The catalyst for methane oxidation reaction according to the present invention can remove methane from a mixed gas by oxidation reaction through a conventional method, and at this time, the oxidation reaction of methane is performed at atmospheric pressure at a temperature of 400 ℃ to 800 ℃, preferably 400 ℃ to 600 ℃, and the volume space velocity is 5,000 h -1 ~ 30,000 h -1 This is desirable in that the deactivation of the catalyst is suppressed in a high-temperature environment.

[0066] Hereinafter, the present invention will be described in more detail through specific examples. The following examples are merely illustrative examples to aid understanding of the present invention and are not intended to limit the scope of the present invention.

[0067] <Example 1>

[0068] As a tin oxide precursor, 175.3 g of stannous chloride pentahydrate [SnCl4ㆍ5H2O, reagent grade, Samjeon Pure Chemicals Co., Ltd.] was dissolved in 2,500 g of distilled water to obtain a tin precursor aqueous solution, and then 1 M ammonium carbonate aqueous solution [(NH4)2CO3, reagent grade, Daejung Chemicals & Metals Co., Ltd.] was slowly added to the obtained tin precursor solution to adjust the pH to 8, and stirred for 1 hour. The stirred solution and the precipitate were separated with a filter paper or filter cloth to obtain a white precipitate, and then the obtained precipitate was thoroughly washed with distilled water to remove impurities such as chloride ions. The precipitate from which the impurities had been removed was dried at 110°C for 12 hours and then calcined at 550°C for 6 hours while flowing air to obtain a tin oxide powder.

[0069] The obtained tin oxide powder was wet-ground, distilled water was added, and stirred to obtain a tin oxide coating solution. The obtained coating solution was used to form a cordierite honeycomb (3.2 cm × 3.2 cm × 5.0 cm, 100 cells / in). 2 ) was washed and coated, and then dried at 110°C for 12 hours, and then calcined at 550°C for 6 hours while allowing air to flow to manufacture a support coated with 400 g / L of tin oxide powder.

[0070] The catalytically active metal was impregnated into the support coated with the above-mentioned tin oxide. At this time, 0.539 g of RuCl3ㆍxH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 2.56 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 15.44 g of distilled water, and then the aqueous solution was impregnated into the support, and dried at 110°C for 12 hours. Afterwards, the dried material was calcined at 550°C for 6 hours while air was supplied to obtain 38 g / ft 3 Ru-38 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0071] <Example 2>

[0072] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, then calcined at 700°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0073] <Example 3>

[0074] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, then calcined at 800°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0075] <Example 4>

[0076] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, then calcined at 900°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0077] <Example 5>

[0078] A catalyst was prepared in the same manner as in Example 1, but 0.431 g of RuCl3ㆍxH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 3.925 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 14.075 g of distilled water, and the aqueous solution was impregnated into a support coated with tin oxide. Afterwards, the impregnated material was dried at 110°C for 12 hours, and the dried material was calcined at 550°C for 6 hours while flowing air to obtain a 30 g / ft 3 Ru-58 g / ft3 A Pt / SnO2 catalyst was prepared.

[0079] <Example 6>

[0080] A catalyst was prepared in the same manner as in Example 1, but 1.042 g of RuCl3ㆍxH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 2.560 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 15.44 g of distilled water, and the aqueous solution was impregnated into a support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a particle size of 94 g / ft. 3 Ru-38 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0081] <Example 7>

[0082] A catalyst was prepared in the same manner as in Example 1, but 1.796 g of RuCl3ㆍxH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 1.707 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 16.293 g of distilled water, and the aqueous solution was impregnated into a support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a particle size of 126 g / ft. 3 Ru-25 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0083] <Example 8>

[0084] A catalyst was prepared in the same manner as in Example 1, but a support coated with 533.3 g / L of tin oxide powder was obtained, and a catalyst was prepared using the obtained support. 0.359 g of RuCl3ㆍxH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 1.707 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 16.293 g of distilled water, and then the aqueous solution was impregnated into the support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a catalyst having a concentration of 25 g / ft. 3 Ru-25 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0085] <Comparative Example 1>

[0086] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, and then calcined at 150°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0087] <Comparative Example 2>

[0088] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, then calcined at 300°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0089] <Comparative Example 3>

[0090] Tin oxide powder was prepared in the same manner as in Example 1, but the tin oxide precipitate obtained through synthesis was dried at 110°C for 12 hours, then calcined at 1000°C for 6 hours while allowing air to flow to obtain tin oxide powder, and a catalyst was prepared in the same manner as in Example 1 using the obtained tin oxide powder.

[0091] Comparative Example 4

[0092] A catalyst was prepared in the same manner as in Example 1, but a support coated with 311.1 g / L of tin oxide powder was obtained, and a catalyst was prepared using the obtained support. 3.072 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor was dissolved in 14.928 g of distilled water, and the aqueous solution was impregnated into the support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a catalyst having a particle size of 45 g / ft. 3 A Pt / SnO2 catalyst was prepared.

[0093] Comparative Example 5

[0094] A catalyst was prepared in the same manner as in Example 1, but 1.258 g of RuCl3xH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor was dissolved in 18 g of distilled water, and the aqueous solution was impregnated into a tin oxide-coated support. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while air was flowing to obtain a particle size of 88 g / ft. 3 A Ru / SnO2 catalyst was prepared.

[0095] Comparative Example 6

[0096] A catalyst was prepared in the same manner as in Example 1, but 1.868 g of RuCl3xH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 1.365 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 16.635 g of distilled water, and the aqueous solution was impregnated into a support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a particle size of 131 g / ft. 3 Ru-20 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0097] <Comparative Example 7>

[0098] A catalyst was prepared in the same manner as in Example 1, but a support coated with 355.6 g / L of tin oxide powder was obtained, and a catalyst was prepared using the obtained support. 0.18 g of RuCl3xH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor and 0.853 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 17.147 g of distilled water, and then the aqueous solution was impregnated into the support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain 13 g / ft 3 Ru-13 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0099] Comparative Example 8

[0100] A catalyst was prepared in the same manner as in Example 1, but a support coated with 88.9 g / L of tin oxide powder was obtained, and a catalyst was prepared using the obtained support.

[0101] Comparative Example 9

[0102] A catalyst was prepared in the same manner as in Example 1, except that 0.347 g of PdCl2 (reagent grade, Sigma-Aldrich) as a palladium precursor and 2.56 g of H2PtCl6 (reagent grade, Sigma-Aldrich) as a platinum precursor were dissolved in 17.653 g of a 5 M hydrochloric acid solution, and then the solution was impregnated into a tin oxide-coated support. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while air was flowing to obtain a particle size of 38 g / ft. 3 Pd-38 g / ft 3 A Pt / SnO2 catalyst was prepared.

[0103] Comparative Example 10

[0104] A catalyst was prepared in the same manner as in Example 1, but 0.347 g of PdCl2 (reagent grade, Sigma-Aldrich) as a palladium precursor and 0.539 g of RuCl3xH2O (reagent grade, Sigma-Aldrich) as a ruthenium precursor were dissolved in 18 g of distilled water, and the aqueous solution was impregnated into a support coated with tin oxide. The impregnated material was dried at 110°C for 12 hours, and then the dried material was calcined at 550°C for 6 hours while flowing air to obtain a particle size of 38 g / ft. 3 Pd-38 g / ft 3 A Ru / SnO2 catalyst was prepared.

[0105] [Experimental Example 1: Evaluation of the physical properties of a catalyst carrier (tin-containing metal oxide)]

[0106] 1-1: Measurement of BET surface area of ​​tin oxide (SnO2)

[0107] The specific surface area of ​​the tin oxide obtained in the examples and comparative examples was measured using a BET analyzer (Tristar II 3020, Micromeritics). Before measurement, the obtained tin oxide was pretreated at 150°C in a vacuum atmosphere for 3 hours to remove impurities and moisture on the surface of the tin oxide, and after the pretreatment, nitrogen gas was used to P / P o= The results measured in the range of 0.05 to 0.3 are shown in Table 1 below.

[0108] 1-2: Measurement of crystal size of tin oxide (SnO2)

[0109] The crystal structure of the tin oxide obtained in the examples and comparative examples was measured using an X-ray diffraction analyzer (SmartLab, Rigaku), and the crystal size was calculated using the Scherrer Equation using the largest peak around 2θ 26.5° among the diffraction peaks obtained under the conditions of an acceleration voltage of 40 kV and a current of 40 mA through a Cu Kα ray wavelength, and is shown in Table 1.

[0110] 1-3: H2-TPR measurement of tin oxide (SnO2)

[0111] The H2-TPR (BELCAT II, ​​Microtrac MRB) analysis of the tin oxide obtained in the examples and comparative examples was measured. The tin oxide was charged into a reactor in the analyzer and pretreated at 250°C for 1 hour in an Ar atmosphere to remove impurities on the tin oxide surface. Then, the temperature was increased to 800°C at 10°C / min in a 5% H2 / Ar atmosphere, and a reduction graph was obtained using a TCD (Thermal Conductivity Detector), and the results are shown in Table 1 below.

[0112] [Table 1]

[0113]

[0114] As shown in Table 1, the tin-containing metal oxides obtained in Examples 1 to 4 had a BET specific surface area of ​​6 m 2 / g ~ 24 m 2 / g, and the crystal size is 12.8 nm to 34.0 nm, and the H2-TPR maximum peak point appears at 683.1 ℃ to 723.2 ℃, while the tin-containing metal oxides obtained in Comparative Examples 1 to 3 have a BET specific surface area of ​​5 m 2 / g ~ 40 m 2 / g, it was confirmed that the crystal size was 10 nm to 40 nm and the H2-TPR maximum peak point was outside the range of 640 ℃ to 735 ℃, respectively.

[0115] [Experimental Example 2: Long-term stability measurement before and after catalyst poisoning]

[0116] 2-1: Measurement of methane conversion rate according to the content ratio of catalytic active metal and catalyst carrier

[0117] Using the catalysts of the examples and comparative examples, a methane oxidation reaction was performed to determine the methane conversion rate. Afterwards, the same catalyst was poisoned with sulfur oxides and a methane oxidation reaction was performed under the same conditions to determine the methane conversion rate, thereby comparing and evaluating the catalytic activity before and after catalyst poisoning. Specifically, each experimental process is as follows.

[0118] (1) Methane oxidation reaction

[0119] Total flow rate 2,250 cm using 2,000 ppmv of methane, 10 vol% of H2O, and air 3 / min, volume space velocity 15,000 h -1 The catalyst was supplied, the oxidation temperature was fixed at 500 ℃, and the prepared catalyst was charged into the reactor to perform the reaction.

[0120] (2) Method for measuring methane conversion rate

[0121] Methane concentration was measured using a methane analyzer (7500 CH4IR Analyzer, Teledyne), and the methane conversion rate was calculated based on the change in methane concentration before and after the reaction. The methane conversion rate was performed identically under two conditions: before and after catalyst poisoning.

[0122] (3) Catalyst poisoning conditions

[0123] Poisoning was performed for a total of 57 hours or more while injecting gas containing 125 ppmv of sulfur dioxide gas under (1) methane oxidation reaction conditions into the catalyst-charged region, and the poisoning temperature was fixed at 500°C. During sulfur poisoning, the methane concentration was measured at 15, 36, and 57 hours of poisoning, and the methane conversion rate and deactivation rate were calculated and shown in Table 2 and Figures 1 and 2. At this time, the deactivation rate after 57 hours of poisoning in Table 2 and Figure 2 below was calculated using mathematical equation 1.

[0124] [Mathematical Formula 1]

[0125] Inactivation rate (%) = (C T0 -C T57 ) / (C T0 ) × 100

[0126] In the above mathematical formula 1, C T0 is the methane conversion measured at the initial time (before poisoning), and C T57 is the methane conversion rate after 57 hours.

[0127] [Table 2]

[0128]

[0129] As shown in Table 2 and FIGS. 1 and 2, the catalysts manufactured in Examples 1 to 8 had a deactivation rate of less than 10% after 57 hours of poisoning, whereas the catalysts manufactured in Comparative Examples 1 to 8 had a deactivation rate of 12% or more after 57 hours of poisoning.

[0130] 2-2: Measurement of methane conversion rate according to catalytic active metal component

[0131] The methane conversion rate and the deactivation rate after 57 hours of poisoning of the catalysts manufactured in Example 1 and Comparative Examples 9 and 10 were measured using the same method as Experimental Example 2-1, and the results are shown in Table 3.

[0132] [Table 3]

[0133]

[0134] As shown in Table 3, the catalyst manufactured in Example 1 had a deactivation rate of less than 4% after 57 hours of poisoning, whereas the catalysts manufactured in Comparative Examples 9 and 10 had a deactivation rate of 34.0% or more after 57 hours of poisoning.

[0135] All simple modifications or changes of the present invention can be easily implemented by a person having ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims

1. A catalyst for methane oxidation reaction that oxidizes methane in a mixed gas containing methane, sulfur oxides, and moisture. The catalyst comprises a tin-containing metal oxide having a crystal size of 10 nm to 40 nm; and a catalytically active metal supported on the tin-containing metal oxide; A catalyst for methane oxidation reaction, characterized in that the catalytically active metal comprises ruthenium and platinum in a weight ratio of 0.1:1.0 to 5.0:1.0, and the weight ratio of the catalytically active metal and tin-containing metal oxide is 1:50 to 1:

300.

2. In paragraph 1, A catalyst for methane oxidation reaction, characterized in that the tin-containing metal oxide has a maximum peak at 640 ℃ to 735 ℃ when analyzed by H2-TPR (hydrogen thermodynamic reduction method).

3. In paragraph 1, The above tin-containing metal oxide has a BET surface area of ​​5 m 2 / g ~ 40 m 2 A catalyst for methane oxidation reaction characterized by / g.

4. A method for manufacturing a catalyst for methane oxidation reaction that oxidizes methane in a mixed gas containing methane, sulfur oxides and moisture, (a) a step of supporting a catalytically active metal on a tin-containing metal oxide so that the weight ratio of the catalytically active metal and the tin-containing metal oxide in the manufactured catalyst is 1:50 to 1:300; and (b) a step of drying and calcining a support on which the catalytically active metal is supported; including, A method for producing a catalyst for methane oxidation reaction, characterized in that in the step (a), the tin-containing metal oxide has a crystal size of 10 nm to 40 nm, the catalytically active metal includes ruthenium and platinum, and the ruthenium and platinum are supported on the tin-containing metal oxide in a weight ratio of 0.1:1.0 to 5.0:1.0 in the produced catalyst.

5. In paragraph 4, A method for producing a catalyst for methane oxidation reaction, characterized in that the tin-containing metal oxide of the above step (a) has a maximum peak at 640 ℃ to 735 ℃ when analyzed by H2-TPR (hydrogen thermodynamic reduction method).

6. In paragraph 4, The tin-containing metal oxide of step (a) above has a BET specific surface area of ​​5 m 2 / g ~ 40 m 2 A method for producing a catalyst for methane oxidation reaction, characterized in that / g.

7. A methane oxidation method characterized by oxidizing methane in a mixed gas containing methane, sulfur oxide, and moisture in the presence of a methane oxidation reaction catalyst according to any one of claims 1 to 3.

8. In paragraph 7, A methane oxidation method characterized in that the above oxidation is performed at 400 ℃ to 800 ℃.

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