Catalyst for removing methane and manufacturing method thereof

Abstract

The present invention provides a catalyst for removing methane and a manufacturing method thereof. The catalyst for removing methane according to one embodiment of the present invention comprises: support powder containing aluminum oxide having a corundum structure; and a catalytic material supported in contact with the support and containing palladium.

Description

Catalyst for methane removal and method for manufacturing the same

[0001] The technical concept of the present invention relates to a method for removing methane, and more specifically, to a catalyst for removing methane and a method for manufacturing the same.

[0002] The present invention relates to project number 2710019259 and project number PNK9750, which were carried out with funding from the Ministry of Science and ICT and support from the Korea Institute of Materials Science.

[0003] To prevent global warming, regulations on greenhouse gases such as carbon dioxide are being widely implemented. Methane (CH4) is a very powerful greenhouse gas with a global warming potential 28 times that of carbon dioxide. According to the IPCC (Intergovernmental Panel on Climate Change) study '2010-2019 Global Warming Contribution Compared to 1850-1990,' the temperature increase caused by carbon dioxide over the past 20 years was 0.8 o While C, the temperature rise due to methane is 0.5 o It has been reported as C. Thus, the strong greenhouse effect of methane has been proven. International methane regulations are also being activated through the Global Methane Pledge, which aims to reduce methane emissions by at least 30% compared to 2020 levels by 2030.

[0004] Recently, the consumption of Liquefied Natural Gas (LNG) has been increasing for the purpose of carbon neutrality. Consequently, the volume of LNG transported by LNG carriers is rising, and furthermore, the number of LNG-powered vessels using natural gas as fuel is rapidly increasing. While the use of LNG-powered vessels reduces carbon dioxide emissions, it presents a problem regarding the emission of unreacted (slip) methane, a potent greenhouse gas. As the amount of methane released into the air due to methane slip increases, there are concerns that it may exacerbate the greenhouse effect. Therefore, methods to remove methane are required to prevent its emission.

[0005] The technical problem that the technical concept of the present invention aims to solve is to provide a catalyst for methane removal and a method for manufacturing the same.

[0006] However, these tasks are exemplary, and the technical concept of the present invention is not limited thereto.

[0007] According to one aspect of the present invention, a catalyst for removing methane and a method for manufacturing the same are provided.

[0008] According to one embodiment of the present invention, the methane removal catalyst may comprise a support powder comprising aluminum oxide with a corundum structure; and a catalytic material comprising palladium that is supported in contact with the support.

[0009] According to one embodiment of the present invention, the methane removal catalyst is 400 o It can exhibit a methane conversion rate in the range of 60% to 99% at temperatures below C.

[0010] According to one embodiment of the present invention, the methane removal catalyst is 300 o C to 400 o A methane conversion rate in the range of 60% to 99% can be maintained for 500 hours at a temperature in the C range.

[0011] According to one embodiment of the present invention, the support powder may contain the corundum-structured aluminum oxide in an amount of 50% to 98% by weight based on the total weight of the support powder.

[0012] According to one embodiment of the present invention, the support may contain the corundum-structured aluminum oxide in an amount of 60% to 95% by weight based on the total weight of the support powder.

[0013] According to one embodiment of the present invention, the support powder is 10 m 2 / g to 60 m 2 It can have a specific surface area in the range of / g.

[0014] According to one embodiment of the present invention, the support powder may further include at least one of theta (θ) phase aluminum oxide, gamma (γ) phase aluminum oxide, and delta (δ) phase aluminum oxide.

[0015] According to one embodiment of the present invention, the support powder may further include at least one of WO3, MoO3, MnO2, Mn2O3, MnO, Mn3O4, CeO2, TiO2, CuO, V2O5, ZnO, SnO2, SiO2, and zeolite.

[0016] According to one embodiment of the present invention, the palladium may be included in an amount of 0.1% to 10% by weight relative to the total weight of the support powder.

[0017] According to one embodiment of the present invention, the palladium may be included in an amount of 0.5% to 6% by weight relative to the total weight of the support powder.

[0018] According to one embodiment of the present invention, the catalyst material may further include at least one of Pt, Ru, Fe, Cu, Ni, Mn, Co, Ag, Au, V, Ti, W, Mo, alloys thereof, and oxides thereof.

[0019] According to one embodiment of the present invention, the support powder and the carrier accommodating the catalyst material may be further included.

[0020] According to one embodiment of the present invention, a method for manufacturing a methane removal catalyst comprises the steps of: preparing a mixed solution by mixing a corundum-structured aluminum oxide powder and a palladium precursor solution containing palladium in a solvent; drying the mixed solution to form a mixed powder; and performing a first heat treatment on the mixed powder to form a powder-type methane removal catalyst, wherein the powder-type methane removal catalyst may include a support containing the corundum-structured aluminum oxide; and a catalytic material containing palladium that is supported in contact with the support.

[0021] According to one embodiment of the present invention, the first heat treatment is 400 o C to 600 o It can be performed at a temperature in the C range.

[0022] According to one embodiment of the present invention, the method may further include the steps of: mixing the first heat-treated methane removal catalyst in a solvent to form a slurry; coating the slurry onto at least a portion of the surface of a carrier; drying the carrier coated with the slurry to coat the first heat-treated methane removal catalyst onto at least a portion of the surface of the carrier; and heat-treating the carrier a second time.

[0023] According to one embodiment of the present invention, the methane removal catalyst prepared after performing the second heat treatment step may comprise: a support comprising aluminum oxide having a corundum structure; a catalytic material comprising palladium that is supported in contact with the support; and a carrier that accommodates the support and the catalytic material.

[0024] According to one embodiment of the present invention, the second heat treatment is 400 o C to 600o It can be performed at a temperature in the C range.

[0025] According to one embodiment of the present invention, a method for manufacturing a catalyst for methane removal may include the steps of: mixing a corundum-structured aluminum oxide powder with a solvent to prepare a slurry; coating the slurry onto at least a portion of the surface of a carrier; drying the carrier coated with the slurry so that the corundum-structured aluminum oxide powder is coated onto at least a portion of the surface of the carrier; performing a third heat treatment on the carrier to form a support composed of the aluminum oxide; contacting the third heat-treated carrier with a palladium precursor solution containing palladium to apply the palladium precursor solution to the support; drying the carrier; and performing a fourth heat treatment on the carrier.

[0026] According to one embodiment of the present invention, the methane removal catalyst prepared after performing the fourth heat treatment step may comprise: a support comprising aluminum oxide having a corundum structure; a catalytic material comprising palladium that is supported in contact with the support; and a carrier that accommodates the support and the catalytic material.

[0027] According to one embodiment of the present invention, the third heat treatment is 400 o C to 600 o It is performed at a temperature in the C range, and the fourth heat treatment is 400 o C to 600 o It can be performed at a temperature in the C range.

[0028] According to the technical concept of the present invention, a methane removal catalyst is configured to include a support comprising aluminum oxide having a corundum structure and a catalytic material comprising palladium that is supported in contact with said support, thereby 400 o Excellent methane conversion performance and durability can be secured at temperatures below C.

[0029] The effects of the present invention described above are illustrative and the scope of the present invention is not limited by these effects.

[0030] FIGS. 1 to 3 are flowcharts illustrating a method for manufacturing a catalyst for methane removal according to an embodiment of the present invention.

[0031] FIG. 4 is a schematic diagram illustrating a monolithic catalyst for methane removal according to an embodiment of the present invention.

[0032] FIG. 5 is a schematic diagram illustrating a manufacturing apparatus for a methane removal catalyst according to an embodiment of the present invention.

[0033] Figure 6 is a graph showing the X-ray diffraction analysis of a catalyst for methane removal according to an embodiment of the present invention.

[0034] Figure 7 shows transmission electron microscope images of a methane removal catalyst according to an embodiment of the present invention.

[0035] FIGS. 8 to 11 are graphs showing the methane conversion rate results of a methane removal catalyst according to an embodiment of the present invention.

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments of the present invention are provided to more fully explain the technical concept of the present invention to those skilled in the art, and the following embodiments may be modified in various different forms, and the scope of the technical concept of the present invention is not limited to the following embodiments. Rather, these embodiments are provided to make the present disclosure more faithful and complete and to fully convey the technical concept of the present invention to those skilled in the art. In this specification, the same reference numerals denote the same elements throughout. Furthermore, various elements and areas in the drawings are depicted schematically. Accordingly, the technical concept of the present invention is not limited by the relative sizes or spacing depicted in the attached drawings.

[0037] The technical concept of the present invention relates to a methane removal catalyst for removing methane contained in exhaust gas emitted from a methane emission source, such as a gas engine or gas burner for ships or automobiles that uses methane gas, such as natural gas, as the primary fuel, or in the exhaust gas of an LNG-propelled vessel, and a method for manufacturing the same.

[0038] Methane can decompose into carbon dioxide and water by chemically reacting with oxygen as follows.

[0039] CH4 + 2O2 -> CO2 + 2H2O

[0040] Methane is a chemically stable substance with high activation energy. Therefore, the catalytic reaction temperature for the decomposition of methane is 400 o High temperatures exceeding C are required. Even when using conventional catalysts, the reaction temperature for the decomposition of methane is 400 o C Exceeding 500 o The range is C or lower. However, recently, the above reaction temperature is 400 o C or less, for example, 300 o C to 400 o There is a requirement to reduce it to the C range.

[0041] A conventional catalyst for methane removal is constructed by using gamma aluminum oxide (γ-alumina, γ-Al2O3) powder as a support and forming palladium particles as a main catalyst on the surface of the gamma aluminum oxide powder. At this time, 450 o C to 550 o It is manufactured by performing calcination heat treatment in the C range. Conventional support powder for catalysts for methane removal is 150 m 2 / gram to 200 m 2 It has a very high specific surface area in the / gram range.

[0042] In addition, exhaust gas or exhaust gas from LNG-propelled vessels contains about 2% to 10% by weight of moisture, and the performance of the above-mentioned conventional catalyst is degraded and its durability is also significantly reduced due to a large amount of water vapor components. Although durability of several hundred to several thousand hours is required for use as a commercial catalyst, the performance of the above-mentioned conventional catalyst decreases rapidly even when used for a short period of time of 100 hours or less.

[0043] A catalyst for methane removal according to one embodiment of the present invention comprises: a support powder comprising aluminum oxide having a corundum structure; and a catalytic material comprising palladium (Pd) that is supported in contact with the support.

[0044] The above methane removal catalyst is, for example, 400 o It can exhibit a methane conversion rate in the range of 60% to 99% at temperatures below C. The above-mentioned methane removal catalyst is, for example, 300 o C to 400 o It can exhibit a methane conversion rate in the range of 60% to 99% at temperatures in the C range.

[0045] The above methane removal catalyst is, for example, 400 o A methane conversion rate in the range of 60% to 99% can be maintained for at least 500 hours at a temperature of C or lower, and furthermore, can be maintained for 1,000 hours. The above-mentioned catalyst for methane removal is, for example, 300 o C to 400 o A methane conversion rate of 60% to 99% can be maintained for at least 500 hours at a temperature in the C range, and furthermore, for 1000 hours.

[0046] The above-mentioned corundum-structured aluminum oxide is the most stable equilibrium phase, 1000 oThe phase stability can be maintained even at ultra-high temperatures above C. Therefore, the catalytic metal and the corundum-structured aluminum oxide serving as a support interact to control the bonding positions, thereby preventing the deactivation of the catalyst during catalyst sintering. Consequently, the corundum-structured aluminum oxide can prevent the degradation of catalyst performance caused by the sintering of the catalytic material. The corundum-structured aluminum oxide has a hexagonal close-packed (hcp) crystal structure. Hereinafter, the corundum-structured aluminum oxide according to the present invention will be referred to as hcp-aluminum oxide.

[0047] Table 1 is a table comparing the characteristics of hcp-aluminum oxide with a corundum structure according to the technical concept of the present invention and gamma aluminum oxide of a comparative example.

[0048] Characteristics Preliminary Comparison Example Aluminum Oxide Type hcp-aluminum oxide gamma aluminum oxide Crystal System Hexagonal or Trigonal Cubic, Face-Centered Cubic Crystal Structure Corundum Structure Spinel Structure Phase Stability Equilibrium Phase Stable Phase Meta-stable Phase Specific Surface Area 10 ~ 60 m² 2 / gram150~ 200 m 2 / gram Methane Conversion Performance Excellent methane conversion performance (= low methane conversion temperature) Low methane conversion performance (= high methane conversion temperature) Methane Conversion Temperature Low High Methane Conversion Durability High Low

[0049] The above support powder may contain the corundum-structured aluminum oxide in, for example, 50% to 98% by weight based on the total weight of the support powder, and may contain, for example, 60% to 95% by weight.

[0050] The above support powder is, for example, 10 m 2 / g to 60 m 2 It can have a specific surface area in the range of / g, for example, 15 m 2 / g to 60 m 2 It can have a specific surface area in the range of / g.

[0051] The above support powder may contain the remainder of other phases of aluminum oxide (Al2O3), and may further include at least one of, for example, theta (θ) phase aluminum oxide, gamma (γ) phase aluminum oxide and delta (δ) phase aluminum oxide.

[0052] The above-mentioned corundum structured aluminum oxide can provide durability, and the above-mentioned theta-phase aluminum oxide can provide enhanced catalytic properties such as reduced methane conversion temperature and increased methane conversion rate.

[0053] For example, the support powder may contain the corundum-structured aluminum oxide in an amount of 50% to 98% by weight based on the total weight of the support, and the remainder may contain the theta-phase aluminum oxide. If the corundum-structured aluminum oxide is contained in an amount exceeding 98% by weight based on the total weight of the support, catalytic properties such as a decrease in methane conversion temperature and an increase in methane conversion rate may be degraded. On the other hand, if the corundum-structured aluminum oxide is contained in an amount of less than 50% by weight based on the total weight of the support, durability may be reduced.

[0054] In order to secure the aforementioned catalytic properties and durability, the support powder may preferably contain 60% to 95% by weight of the corundum-structured aluminum oxide based on the total weight of the support and the remainder of the theta-phase aluminum oxide. Alternatively, the support powder may more preferably contain 75% to 85% by weight of the corundum-structured aluminum oxide based on the total weight of the support and the remainder of the theta-phase aluminum oxide.

[0055] The above support powder may further include at least one of WO3, MoO3, MnO2, Mn2O3, MnO, Mn3O4, CeO2, TiO2, CuO, V2O5, ZnO, SnO2, SiO2, and zeolite.

[0056] The catalyst material comprises palladium (Pd). The palladium may be included in, for example, 0.1% to 10% by weight and, for example, 0.5% to 6% by weight, based on the total weight of the support powder.

[0057] The above catalyst material may further include at least one of Pt, Ru, Fe, Cu, Ni, Mn, Co, Ag, Au, V, Ti, W, Mo, alloys thereof, and oxides thereof.

[0058] The above-described methane removal catalyst may be formed in a powder form. Alternatively, the above-described methane removal catalyst may further include a carrier that accommodates the support powder and the catalyst material, and may be referred to as a monolithic catalyst.

[0059] FIGS. 1 to 3 are flowcharts illustrating a method for manufacturing a catalyst for methane removal according to an embodiment of the present invention.

[0060] Referring to FIG. 1, a method for manufacturing a methane removal catalyst (S100) comprises the steps of: preparing a mixed solution by mixing a corundum-structured aluminum oxide powder and a palladium precursor solution containing palladium in a solvent (S110); drying the mixed solution to form a mixed powder (S120); and performing a first heat treatment on the mixed powder to form a powder-type methane removal catalyst (S130).

[0061] The above powder-type methane removal catalyst may include a support comprising the above-mentioned corundum-structured aluminum oxide; and a catalytic material comprising palladium that is supported in contact with the support.

[0062] The above palladium precursor solution may include various solutions containing palladium, for example, palladium chloride or palladium nitrate.

[0063] The above solvent may include various solutions, and may include, for example, water or alcohol.

[0064] The above drying is, for example, 20 o C to 200 o It can be performed at a temperature in the C range, for example, for 1 minute to 24 hours.

[0065] The above first heat treatment is, for example, 400 o C to 600 o It can be performed at a temperature in the C range, for example, for 1 minute to 24 hours.

[0066] Referring to FIG. 2, a method for manufacturing a methane removal catalyst (S200) comprises the steps of: preparing a mixed solution by mixing a corundum-structured aluminum oxide powder and a palladium precursor solution containing palladium in a solvent (S210); drying the mixed solution to form a mixed powder (S220); performing a first heat treatment on the mixed powder to form a powder-type methane removal catalyst (S230); mixing the first heat-treated methane removal catalyst in a solvent to form a slurry (S240); coating the slurry onto at least a portion of the surface of a carrier (S250); drying the carrier coated with the slurry to coat the first heat-treated methane removal catalyst onto at least a portion of the surface of the carrier (S260); and performing a second heat treatment on the carrier (S270). Accordingly, a monolith-type methane removal catalyst can be formed.

[0067] The methane removal catalyst prepared after performing the second heat treatment step (S270) may include: a support comprising aluminum oxide having a corundum structure; a catalytic material comprising palladium that is supported in contact with the support; and a carrier that accommodates the support and the catalytic material.

[0068] The above solvent may include various solutions, and may include, for example, water or alcohol.

[0069] The above second heat treatment is, for example, 400 o C to 600 o It can be performed at a temperature in the C range, for example, for 1 minute to 24 hours.

[0070] Referring to FIG. 3, a method for manufacturing a catalyst for methane removal (S300) comprises the steps of: preparing a slurry by mixing corundum-structured aluminum oxide powder with a solvent (S310); coating the slurry onto at least a portion of the surface of a carrier (S320); drying the carrier coated with the slurry so that the corundum-structured aluminum oxide powder is coated onto at least a portion of the surface of the carrier (S330); performing a third heat treatment on the carrier to form a support composed of the aluminum oxide (S340); contacting the third heat-treated carrier with a palladium precursor solution containing palladium to apply the palladium precursor solution to the support (S350); drying the carrier (S360); and performing a fourth heat treatment on the carrier (S370). Accordingly, a monolithic catalyst for methane removal can be formed.

[0071] The methane removal catalyst prepared after performing the fourth heat treatment step (S370) may include: a support comprising aluminum oxide having a corundum structure; a catalytic material comprising palladium that is supported in contact with the support; and a carrier that accommodates the support and the catalytic material.

[0072] The above solvent may include various solutions, and may include, for example, water or alcohol.

[0073] The above third heat treatment is, for example, 400 o C to 600 o It can be performed at a temperature in the C range, for example, for 1 minute to 24 hours.

[0074] The above fourth heat treatment is, for example, 400 o C to 600 o It can be performed at a temperature in the C range, for example, for 1 minute to 24 hours.

[0075] FIG. 4 is a schematic diagram illustrating a monolithic catalyst for methane removal according to an embodiment of the present invention.

[0076] Referring to FIG. 4, a monolithic methane removal catalyst (100) is illustrated. The monolithic methane removal catalyst (110) includes a substrate (110) and a catalyst region (130).

[0077] The catalyst region (130) may include a support comprising aluminum oxide having a corundum structure; and a catalytic material comprising palladium that is supported in contact with the support. The support and the catalytic material are as described above.

[0078] The carrier (110) may have one or more fluid channels (120) through which fluid can flow, and may have a porous structure having a plurality of pores. The carrier (110) may include a plurality of fluid channels (120) extending from one end to the other end.

[0079] One end of the flow path (120) may be an inlet for introducing fluid, and the other end may be an outlet for discharging fluid. The carrier (110) may be formed by a plurality of adjacent flow paths having a square cross-section extending from one end to the other. As another example, the cross-section of the flow path may be in the shape of a honeycomb with a regular hexagon. There are no special limitations on the cross-sectional shape, such as triangles or circles, and any shape is possible as long as it is a flow path capable of allowing fluid to flow into the interior of the carrier (110). As another example of the structure of the carrier (110), the carrier (110) may be a porous material, such as a porous metal, that includes a plurality of empty spaces inside and in which the empty spaces are connected to each other to form a flow path.

[0080] The carrier (110) may be composed of ceramic and may include, for example, cordierite, SiC-based compounds, AlN-based compounds, BaTiO3-based compounds, etc. Alternatively, the carrier (110) may be composed of metal and may include, for example, nickel-chromium alloy, iron-nickel alloy, iron-chromium alloy, stainless steel, Kanthal alloy, etc.

[0081] The above fluid may be a methane-containing gas.

[0082] A catalyst region (130) is formed on the inner surface and within the pores of the flow channel (120) of the carrier (110) to perform a catalytic function for a reaction that removes methane from a methane-containing gas passing through the flow channel (120).

[0083] FIG. 5 is a schematic diagram illustrating a manufacturing apparatus for a methane removal catalyst according to an embodiment of the present invention.

[0084] Referring to FIG. 5, the manufacturing apparatus (200) for a methane removal catalyst is a device that enables catalytic material coating by fixing a carrier (110) requiring a catalytic material coating process in close contact, creating a vacuum atmosphere in the internal space, and then releasing the vacuum atmosphere so that a slurry (S) corresponding to a catalytic material solution penetrates into the carrier (110) due to a pressure difference. To this end, the manufacturing apparatus (200) for a methane removal catalyst comprises a rack (210) to which a carrier (110) is fixed in close contact, a hopper (220) that stores a slurry (S) containing a catalyst material and selectively supplies it to the carrier (110), a supply pipe (230) that communicates with the rack (210) and guides the flow direction of the slurry (S) that has passed through the carrier (110) and the rack (210), a chamber (240) that stores the slurry (S) that has sequentially passed through the carrier (110) and the supply pipe (230), a discharge pipe (250) that selectively discharges gas inside the chamber (240), a valve (260) that selectively blocks the supply pipe (230) and the discharge pipe (250), a vacuum pump (270) that creates a vacuum atmosphere inside the chamber (240) depending on whether the valve (260) is open, and the vacuum pump (270). It is configured to include an exhaust pipe (280) that exhausts the passing gas to the outside, and a control unit (290) that controls the operation of a valve (260) and a vacuum pump (270).

[0085] Most of the above-described components are housed inside a hollow rectangular case (not shown), and for the convenience of the coating process, a rack (210) and a hopper (220) are exposed on the upper side of the case. That is, a rack (210) is formed on the upper surface of the case to have a tubular shape that penetrates the inside of the case, and a carrier (110) is seated and fixed on the rack (210).

[0086] In an embodiment of the present invention, the carrier (110) is formed of ceramic, but it is understood that it can be changed to various materials.

[0087] The rack (210) is configured such that the shape of its open upper portion corresponds to the outer shape of the carrier (110), thereby enabling it to accommodate the carrier (110) inside, and the carrier (110) inserted into the rack (210) has its interior communicating with the interior of the rack (210). A hopper (220) is provided on the upper side of the carrier (110). The hopper (220) is configured to form a space for storing a slurry (S) containing a catalyst material, and is configured such that its lower portion is closely coupled to the upper side of the carrier (110) like the rack (210), and its upper portion is recessed to a predetermined depth to allow for the storage of the slurry (S). Additionally, the open upper space of the hopper (220) is opened downward so that the slurry (S) stored in the upper portion can flow into the interior of the carrier (110).

[0088] A supply pipe (230) is provided at the bottom of the rack (210). The supply pipe (230) is configured to create a path through which the slurry (S) stored in the hopper (220) can move after passing through the carrier (110) and the inside of the rack (210), and is connected to communicate with the inside of the chamber (240). Accordingly, the slurry (S) that remains coated while passing through the inside of the carrier (110) can be stored by flowing into the inside of the chamber (240) through the supply pipe (230).

[0089] The chamber (240) is configured to store excess slurry (S) so that selective discharge of the slurry (S) is possible. That is, the chamber (240) consists of a container part (242) having a container shape to store the slurry (S) and a shielding part (244) for selectively shielding the container part (242). In an embodiment of the present invention, the container part (242) is configured to be easily detachable from the shielding part (244), and the supply pipe (230) is connected to the shielding part (244) so ​​that when the shielding part (244) and the container part (242) are combined in a sealed state, the supply pipe (230) can guide the slurry (S) into the internal space of the container part (242).

[0090] A discharge pipe (250) is provided on one side of the chamber (240). The discharge pipe (250) is connected to communicate with the internal space of the chamber (240) so that gas inside the chamber (240) can be discharged to the outside. That is, it is configured so that when slurry (S) and external gas are introduced into the chamber (240), only the gas can be selectively discharged.

[0091] The chamber (240) is configured so that a vacuum atmosphere can be selectively created by the operation of the valve (260) and the vacuum pump (270). That is, a supply valve (262) is provided on one side of the supply pipe (230), and a discharge valve (264) is provided on one side of the discharge pipe (250). By operating the supply valve (262) and the discharge valve (264), the supply pipe (230) and the discharge pipe (250) are sealed, thereby enabling the chamber (240) to be sealed. When the vacuum pump (270) is operated while only the discharge pipe (250) is open, a vacuum atmosphere can be created inside the chamber (240). Additionally, the supply valve (262) and the discharge valve (264) are configured to have a built-in timer function so that they can be opened or closed for a preset time. Furthermore, the supply valve (262) and the discharge valve (264) are configured so that their opening degree can be adjusted by selectively controlling them by a control unit. This is to prevent the creation of an excessive vacuum atmosphere inside the chamber (240) during the operation of the vacuum pump (270).

[0092] A first filter (252) and a second filter (254) are embedded in one side of the discharge pipe (250). The first filter (252) and the second filter (254) are configured to filter out oil or foreign matter that may be discharged through the discharge pipe (250) from inside the chamber (240) and prevent it from entering the vacuum pump (270). That is, the first filter (252) is positioned adjacent to the chamber (240) to perform the function of removing foreign matter from the air discharged from inside the chamber (240), and the second filter (254) is positioned adjacent to the vacuum pump (270) to remove oil that may enter the vacuum pump (270).

[0093] Meanwhile, a pressure sensor (246) is provided on one side of the chamber (240), that is, on the shielding part (244). The pressure sensor (246) is configured to measure the pressure of the vacuum atmosphere created inside the chamber (240) and performs the role of providing this measured pressure to the control unit.

[0094] The manufacturing apparatus (200) for a methane removal catalyst may further include a control unit (290), and the control unit (290) is configured to enable overall operation of the methane removal catalyst (200) by controlling the operation of the vacuum pump (270) by comparing the vacuum level inside the chamber (240) provided by the pressure sensor (246) with a preset set pressure range, as well as setting the opening degree and opening time of the supply valve (262) and the discharge valve (264).

[0095] Below, a method for coating a catalyst material onto a carrier (110) using a methane removal catalyst manufacturing device (200) is described.

[0096] First, the carrier (110) is fixed in close contact with the rack (210), and the slurry (S) containing the catalyst material is supplied to the carrier (110) in a hopper (220). In this process, the carrier (110), the slurry (S), etc. are prepared and set in the methane removal catalyst (200). The carrier (110) is seated so that its interior communicates with the interior of the rack (210), the hopper (220) is seated on the upper part of the carrier (110), and the slurry (S) is injected into the interior of the hopper (220) and stored. Then, the interior of the rack (210) and the interior of the chamber (240) are disconnected. That is, the supply valve (262) is operated to shield the inside of the supply pipe (230), and the discharge valve (264) is opened to prepare the chamber (240) and the vacuum pump (270) to be in communication.

[0097] Next, a vacuum atmosphere is created inside a chamber (240) for storing the slurry (S) that has passed through the carrier (110). In this process, a vacuum pump (270) is operated to generate suction force, and this suction force is transmitted to the chamber (240) through the discharge pipe (250), thereby forcing the creation of a vacuum atmosphere inside the chamber (240). At this time, the discharge pipe (250) is selectively shielded so that the vacuum level inside the chamber (240) can be maintained at a constant level. That is, the vacuum level inside the chamber (240) increases due to the operation of the vacuum pump (270), and when this vacuum level reaches a preset vacuum level range, the pressure sensor (246) detects this and provides it to the control unit, thereby the control unit shields the discharge valve (264) to maintain the vacuum level inside the chamber (240). At the same time, it is preferable for the control unit to cut off the power supplied to the vacuum pump (270).

[0098] Next, the chamber (240) and the carrier (110) are opened to release the vacuum atmosphere, thereby allowing the slurry (S) to penetrate into the carrier (110) and coat the slurry (S). This process is substantially a step in which the catalyst material is coated into the carrier (110), and is completed by opening the supply pipe (230). More specifically, since the chamber (240) is in a vacuum atmosphere, when the supply valve (262) is opened, the chamber (240) provides suction force to the supply pipe (230), the rack (210), and the carrier (110), and this suction force draws the slurry (S) into the carrier (110). Some of the slurry (S) sucked into the carrier (110) passes through the inside of the carrier (110) and is coated on the wall of the flow path (120), while the remaining uncoated slurry (S) flows downward along the rack (210) and the supply pipe (230) and is fed into the chamber (240) for storage. Thus, the slurry (S) can be coated inside the carrier (110) by the instantaneous opening operation of the supply valve (262).

[0099] After the above process, the coating of the catalyst material is completed, and subsequently, the discharge valve (264) is opened, the supply valve (262) is closed, and the vacuum pump (270) is operated until the pressure inside the chamber (240) reaches a value within the set pressure range. Along with this process, the inside of the chamber (240) is vacuumed again. Of course, before the vacuum is re-formed, one side of the other carrier (110) requiring coating is placed on the rack (210), and the other side of the carrier (110) is placed on the hopper (220) to prepare for the coating of the catalyst material.

[0100] Experimental Example

[0101] Preferred experimental examples are presented below to aid in understanding the present invention. However, the following experimental examples are intended only to aid in understanding the present invention and do not limit the present invention. Details not described herein can be sufficiently technically inferred by those skilled in the art, so their description is omitted.

[0102] The powdered methane removal catalyst of the example was prepared as follows. A mixed solution was prepared by mixing 29.4 g of corundum-structured aluminum oxide powder and 2.766 g of a palladium precursor solution containing palladium (palladium content 21.69 wt%) in 600 ml of water. After injecting the mixed solution into an evaporator flask, 80 o A mixed powder was formed by drying at C for 1 hour. The above mixed powder was 500 o A powdered catalyst for methane removal was formed by heat treatment at C for 4 hours. In the methane removal catalyst, the palladium catalyst was 2 wt%, and the remainder was aluminum oxide.

[0103] In addition, the monolithic methane removal catalyst of the example was formed by coating a powdered methane removal catalyst onto the inner wall of a honeycomb carrier channel according to the slurry formation and drying method, as described above.

[0104] Comparative Examples 1 to 4 were prepared as powder-type catalysts for methane removal. In Comparative Examples 1 to 4, the aluminum oxide powder differs from that of the Examples, and the process following the step of forming a mixed solution was performed in the same manner as in the Examples. In Comparative Examples 1 to 4, palladium is contained in an amount of 2% by weight as a catalyst.

[0105] Comparative Example 1 used commercial product MI307 powder of gamma aluminum oxide.

[0106] Comparative Example 2 used a mixed powder in which the MI307 powder and the corundum-structured aluminum oxide powder of the example were mixed in a weight ratio of 1:1. Thus, it is a powder mixed with hcp aluminum oxide powder and gamma aluminum oxide.

[0107] Comparative Example 3 uses 1300 of the above MI307 powder o hcp aluminum oxide powder formed by heat treatment at C was used.

[0108] Comparative Example 4 used a commercial product of hcp aluminum oxide (Sasol).

[0109] Figure 6 is a graph showing the X-ray diffraction analysis of a catalyst for methane removal according to an embodiment of the present invention.

[0110] Referring to Fig. 6, the methane removal catalyst of the example was mostly hcp crystalline phase Al2O3 with a corundum structure, and a small amount of theta crystalline phase Al2O3 appeared. The hcp crystalline phase Al2O3 was measured to be about 81.4 wt%, and the theta crystalline phase Al2O3 was measured to be about 18.6 wt%.

[0111] Figure 7 shows transmission electron microscope images of a methane removal catalyst according to an embodiment of the present invention.

[0112] Referring to FIG. 7, the methane removal catalyst of the example has a number of small palladium particles formed on the surface of hcp crystalline Al2O3 particles and is indicated in the black circle area. The palladium particles were found to have a diameter in the range of 1 nm to 10 nm.

[0113] Table 2 is a table showing the phase fractions according to X-ray diffraction analysis of a methane removal catalyst according to one embodiment of the present invention, compared with comparative examples. The phase fraction is expressed in weight%.

[0114] Classification Main Substance hcp-Al2O3 θ-Al2O3 γ-Al2O3 Example hcp-Al2O3 81.4 18.60 Comparative Example 1 γ-Al2O3 05.9 94.1 Comparative Example 2 hcp-Al2O3+ γ-Al2O3 47.1 10.2 42.7 Comparative Example 3 hcp-Al2O3 10000 Comparative Example 4 hcp-Al2O3 10000

[0115] Referring to Table 2, the example comprises 81.4 wt% hcp-Al2O3 and 18.6 wt% θ-Al2O3, as described with reference to FIG. 6.

[0116] Comparative Example 1 does not contain hcp-Al2O3 and contains mostly γ-Al2O3.

[0117] Comparative Example 2 contains hcp-Al2O3 and γ-Al2O3 at nearly similar levels, and contains a small amount of θ-Al2O3 provided in the aluminum oxide of the example.

[0118] Comparative Examples 3 and 4 contain only hcp-Al2O3.

[0119] Table 3 is a table showing the BET results of a methane removal catalyst according to one embodiment of the present invention compared with comparative examples.

[0120] Classification Major Materials Specific Surface Area (m²) 2 / g) Pore volume (cm²) 3 / g) Example hcp-Al2O3 20.9 0.11 Example 2 wt% Pd @ hcp-Al2O3 15.7 0.08 Comparative Example 1 γ-Al2O3 15 60.82 Comparative Example 1 2 wt% Pd @ γ-Al2O3 15 30.80 Comparative Example 2 hcp-Al2O3 + γ-Al2O3 90.9 0.47 Comparative Example 3 hcp-Al2O3 6.6 60.02 Comparative Example 4 hcp-Al2O3 8.1 80.03

[0121] Referring to Table 3, it can be seen that the aluminum oxide powder of the Example has a smaller specific surface area and pore volume compared to Comparative Examples 1 and 2. Additionally, it can be seen that the aluminum oxide powder of the Example has a larger specific surface area and pore volume compared to Comparative Examples 3 and 4. Therefore, the Example is 10 m 2 / g to 60 m 2 It is desirable to have a specific surface area in the range of / g.

[0122] In the case of containing 2 wt% palladium, it can be seen that the specific surface area and pore volume of the example are smaller compared to Comparative Example 1.

[0123] Considering the trends in the change of specific surface area and pore volume of the Example and Comparative Example 1 before and after the inclusion of 2 wt% palladium, the specific surface area and pore volume of Comparative Examples 2 to 4 after the inclusion of palladium can be predicted. Therefore, when palladium is included, it can be expected that the specific surface area and pore volume of the Example will be smaller than that of Comparative Example 2, and larger than that of Comparative Examples 3 and 4.

[0124] FIGS. 8 to 12 are graphs showing the methane conversion rate results of a methane removal catalyst according to an embodiment of the present invention.

[0125] The following methane removal catalysts, both in the examples and comparative examples, contain 2 weight percent of palladium.

[0126] The conditions for the following temperature test were as follows. The amount of catalyst for methane removal was 60 mg. The target gas consisted of 1000 volume ppm of methane (CH4), 15 volume% of oxygen (O2), 5 volume% of water vapor (H2O), and the remainder being nitrogen (N2). The flow rate of the target gas was 200 sccm.

[0127] The conditions for the following durability test were as follows. The amount of catalyst for methane removal was 60 mg. The target gas consisted of 1,000 volume ppm methane (CH4), 15 volume% oxygen (O2), 5 volume% water vapor (H2O), and the remainder nitrogen (N2). The flow rate of the target gas was 200 sccm. The test temperature was 360 o C, the example was carried out for up to 528 hours, and Comparative Example 1 was terminated when the methane conversion rate became 0%.

[0128] Referring to Fig. 8, the results of the light-off test of the powder-type methane removal catalysts of the Example and Comparative Example 1 are shown.

[0129] In the example, the 50% methane conversion temperature was 336 o C, 80% methane conversion temperature is 371 o C, and the 90% methane conversion temperature is 396 o It was found to be C. The maximum methane conversion rate is 450 o It was found to be 99.5% at C. In Comparative Example 1, the 50% methane conversion temperature was 386 o C, 80% methane conversion temperature is 427 o C, and the 90% methane conversion temperature is 449 o It was found to be C. The maximum methane conversion rate is 450 o It was found to be 90.8% at C. As additional comparative data, magnesium oxide (MgO) containing 2 wt% palladium showed a very low methane conversion rate. Therefore, it can be seen that the example has excellent methane conversion performance, as the methane conversion temperature is lower and the maximum methane conversion rate is higher compared to Comparative Example 1.

[0130] Referring to Fig. 9, the durability results of the powder-type methane removal catalysts of the Example and Comparative Example 1 are shown.

[0131] In the example, 360 oIt started with a high methane conversion rate of about 70% at C, and during the end time (528 hours), a methane conversion rate in the range of about 60% to 80% was observed, and strictly speaking, a methane conversion rate in the range of 65% to 78% was observed. In Comparative Example 1, 360 o It started with a low methane conversion rate of about 30% at C, the methane conversion rate decreased rapidly over time, and ended at 116 hours. In other words, it can be seen that the methane conversion performance of Comparative Example 1 deteriorated rapidly and became completely inactive after about 100 hours. Therefore, compared to Comparative Example 1, the Example is 360 o As it starts with a high methane conversion rate at low temperatures of C and is maintained, it can be seen that the durability for methane conversion is excellent.

[0132] Therefore, it can be seen that the example containing corundum-structured aluminum oxide is superior to Comparative Example 1, which is composed of gamma aluminum oxide, in both methane conversion rate and durability.

[0133] Referring to Fig. 10, the durability results of the monolithic methane removal catalyst of the example are shown.

[0134] The conditions for the durability test of the above-mentioned monolithic methane removal catalyst are as follows. The methane removal catalyst was prepared in a monolithic form. The amount of methane removal catalyst introduced into the carrier was 177 g / L. The target gas consisted of 2,000 volume ppm methane (CH4), 15 volume% oxygen (O2), 5 volume% carbon dioxide (CO2), 5 volume% water vapor (H2O), and the remainder being nitrogen (N2). The flow velocity of the target gas was 4.1 LPM (space velocity was 20,000 h⁻¹). -1 It was Lim). The test temperature was 400 o It was C, and ended at 1,116 hours.

[0135] In the example, 400 oIt started with a high methane conversion rate of over 99% at C and exhibited a methane conversion rate of over 99% at almost the same level during the end time (1,116 hours). Therefore, in the example, when formed in a monolithic form, 400 o It starts with a high methane conversion rate at low temperatures of C and is maintained for a long time, indicating excellent durability for methane conversion.

[0136] Referring to FIG. 11, the results of the light-off test of the powdered methane removal catalysts of the examples and comparative examples are shown. Compared to the examples, the other comparative examples, excluding Comparative Example 2, showed a low methane conversion rate over the entire temperature range.

[0137] Referring to FIG. 12, the durability results of the powdered methane removal catalysts of the examples and comparative examples are shown. It can be seen that all comparative examples exhibit lower durability compared to the examples. In particular, it can be seen that Comparative Example 2, which had an excellent methane conversion rate in the temperature increase test, also has low durability.

[0138] Analyzing the results of FIGS. 11 and 12, even if hcp-Al2O3 is included as a support as in the example, the specific surface area is 10 m², which is within the range of the present invention. 2 / g to 60 m 2 It can be seen that when the value deviates from / g, the methane conversion rate and durability decrease. Specifically, Comparative Example 2 has a specific surface area of ​​60 m², which is the upper limit of the present invention. 2 In cases where it exceeds / g, it can be seen that while the methane conversion rate is excellent, durability is reduced. Comparative Examples 3 and 4 have a specific surface area of ​​10 m², which is the lower limit of the present invention. 2 It can be seen that when the value is less than / g, the methane conversion rate and durability decrease. Therefore, it can be seen that the specific surface area is a very important factor in securing characteristics such as methane conversion rate and durability.

[0139] In addition, Comparative Example 2 is a case in which the aluminum oxide of the example, hcp-Al2O3, is included at 47.1 wt%, and a result was observed in which durability was reduced. Therefore, it is preferable that the aluminum oxide of the example contains at least 50 wt% of hcp-Al2O3.

[0140] It will be obvious to those skilled in the art that the technical concept of the present invention described above is not limited to the aforementioned embodiments and attached drawings, and that various substitutions, modifications, and changes are possible within the scope of the technical concept of the present invention. Accordingly, the scope of rights of the present invention should be determined by the claims set forth below.

Claims

1. A support powder comprising aluminum oxide of a corundum structure; and Supported in contact with the above support, and comprising a catalytic material including palladium, Catalyst for methane removal.

2. In Paragraph 1, The above-mentioned methane removal catalyst is, 400 o Exhibiting a methane conversion rate in the range of 60% to 99% at temperatures below C, Catalyst for methane removal.

3. In Paragraph 1, The above-mentioned methane removal catalyst is, 300 o C to 400 o Maintaining a methane conversion rate in the range of 60% to 99% for 500 hours at a temperature in the C range, Catalyst for methane removal.

4. In Paragraph 1, The above support powder is, A corundum-structured aluminum oxide comprising 50% to 98% by weight based on the total weight of the support powder, Catalyst for methane removal.

5. In Paragraph 1, The above support powder is, A corundum-structured aluminum oxide comprising 60% to 95% by weight based on the total weight of the support powder, Catalyst for methane removal.

6. In Paragraph 1, The above support powder is, 10 m 2 / g to 60 m 2 having a specific surface area in the range of / g, Catalyst for methane removal.

7. In Paragraph 1, The above support powder is, further comprising at least one of theta (θ) phase aluminum oxide, gamma (γ) phase aluminum oxide, and delta (δ) phase aluminum oxide, Catalyst for methane removal.

8. In Paragraph 1, The above support powder is, further comprising at least one of WO3, MoO3, MnO2, Mn2O3, MnO, Mn3O4, CeO2, TiO2, CuO, V2O5, ZnO, SnO2, SiO2, and zeolite, Catalyst for methane removal.

9. In Paragraph 1, The above palladium is included in an amount of 0.1% to 10% by weight based on the total weight of the support powder, Catalyst for methane removal.

10. In Paragraph 1, The above palladium is included in an amount of 0.5% to 6% by weight based on the total weight of the support powder, Catalyst for methane removal.

11. In Paragraph 1, The above catalyst material is, Pt, Ru, Fe, Cu, Ni, Mn, Co, Ag, Au, V, Ti, W, Mo, alloys thereof, and at least one of the oxides thereof further comprising, Catalyst for methane removal.

12. In Paragraph 1, A carrier further comprising the above-mentioned support powder and the above-mentioned catalyst material, Catalyst for methane removal.

13. A step of preparing a mixed solution by mixing a corundum-structured aluminum oxide powder and a palladium precursor solution containing palladium in a solvent; A step of drying the above mixed solution to form a mixed powder; and The method includes the step of forming a powder-type methane removal catalyst by performing a first heat treatment on the above-mentioned mixed powder. The above-described powder-type methane removal catalyst comprises: a support comprising the above-described corundum-structured aluminum oxide; and a catalytic material comprising palladium that is supported in contact with the support. Method for manufacturing a catalyst for methane removal.

14. In Paragraph 13, The above first heat treatment is, 400 o C to 600 o Performed at a temperature in the C range, Method for manufacturing a catalyst for methane removal.

15. In Paragraph 13, A step of forming a slurry by mixing the above-mentioned first heat-treated methane removal catalyst with a solvent; A step of coating the above slurry onto at least a portion of the surface of a carrier; A step of drying the carrier coated with the slurry to coat the first heat-treated methane removal catalyst on at least a portion of the surface of the carrier; and A further comprising the step of heat-treating the above carrier in a second step, Method for manufacturing a catalyst for methane removal.

16. In Paragraph 15, The methane removal catalyst manufactured after performing the above second heat treatment step is, A support comprising the above-mentioned corundum structured aluminum oxide; A catalytic material comprising palladium that is supported in contact with the above-mentioned support; and A support comprising the above support and a carrier accommodating the above catalyst material, Method for manufacturing a catalyst for methane removal.

17. In Paragraph 15, The above second heat treatment is, 400 o C to 600 o Performed at a temperature in the C range, Method for manufacturing a catalyst for methane removal.

18. A step of preparing a slurry by mixing corundum-structured aluminum oxide powder with a solvent; A step of coating the above slurry onto at least a portion of the surface of a carrier; A step of drying the carrier coated with the slurry, so that the aluminum oxide powder having a corundum structure is coated on at least a portion of the surface of the carrier; A step of forming a support composed of aluminum oxide by performing a third heat treatment on the above carrier; A step of contacting the third heat-treated carrier with a palladium precursor solution containing palladium, and applying the palladium precursor solution to the support; A step of drying the above carrier; and A step comprising a fourth heat treatment of the above carrier, Method for manufacturing a catalyst for methane removal.

19. In Paragraph 18, The methane removal catalyst manufactured after performing the above-mentioned fourth heat treatment step is, A support comprising the above-mentioned corundum structured aluminum oxide; A catalytic material comprising palladium that is supported in contact with the above-mentioned support; and A support comprising the above support and a carrier accommodating the above catalyst material, Method for manufacturing a catalyst for methane removal.

20. In Paragraph 18, The above third heat treatment is 400 o C to 600 o It is performed at a temperature in the C range, and The above fourth heat treatment is 400 o C to 600 o Performed at a temperature in the C range, Method for manufacturing a catalyst for methane removal.

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