Catalyst for reforming methane-containing gas, method for producing the same, and method for reforming methane-containing gas using the same

Abstract

The present invention provides a catalyst for reforming methane-containing gases that exhibits excellent resistance to coke deposition while suppressing catalytic sintering phenomena. [Solution] The present invention relates to a catalyst for reforming methane-containing gas, a method for producing the same, and a method for reforming methane-containing gas using the same, wherein the catalyst for reforming methane-containing gas comprises a porous carrier and an active metal supported within the porous carrier; the active metal comprises nickel; the porous carrier comprises calcium aluminate (CaAl2O4), a modified inorganic binder, and water; the modified inorganic binder comprises an aluminum compound and an alkaline earth metal compound, and the compressive strength of the porous carrier, as measured by a compressive strength meter, is 300 N or more.

Description

[Technical Field]

[0001] The present invention relates to a catalyst for reforming methane-containing gas, a method for producing the same, and a method for reforming methane-containing gas using the same. [Background technology]

[0002] Generally, the main component of natural gas, steelmaking by-product gas, or biogas is methane, and the reaction to produce hydrogen from such methane-containing gases is an endothermic reaction. For this reason, the reforming reaction of methane-containing gases is carried out at high temperatures, and excess steam is injected to reduce the rate of coke formation that inevitably occurs during the reaction.

[0003] The currently commercialized reaction of methane and steam (reaction equation 1 below) is carried out in the presence of a catalyst at a temperature range of 800 to 1,000°C, with a steam / methane ratio (generally called the steam / carbon or S / C ratio) of 1.0 to 3.0, producing a synthesis gas of hydrogen and carbon monoxide. Reaction equation 1 (methane steam reforming reaction): CH4 + H2O → CO + 3H2

[0004] Furthermore, the carbon monoxide produced by the reaction of methane and water vapor is introduced into the water-gas conversion reaction (reaction equation 2 below) to generate more hydrogen, contributing to an increased hydrogen yield. Reaction equation 2 (carbon monoxide water-gas conversion reaction): CO + H2O → CO2 + H2

[0005] In relation to this, the theoretical conversion reaction equation from natural gas or biogas containing methane as its main component to hydrogen is as follows: Overall reaction equation (Reaction Equation 1 + Reaction Equation 2): CH4 + H2O → CO2 + 4H2

[0006] Hereinafter, "conversion reaction from natural gas or biogas containing methane as the main component to hydrogen" is referred to as "reforming of methane-containing gas," and it is common to use a catalyst for reforming such methane-containing gas by supporting an active metal (for example, nickel) on a porous carrier in oxide form.

[0007] However, the active metal within the catalyst gradually aggregates and sintersects at high temperatures, resulting in larger particles, which has the disadvantage of accelerating the deactivation rate of the catalyst. Furthermore, if the coke generated during the reforming reaction settles in the internal pores of the porous support, it can cause cracking / destruction of the catalyst itself. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] One embodiment provides a catalyst for reforming methane-containing gases that exhibits excellent resistance to coke deposition while suppressing catalytic sintering phenomena. [Means for solving the problem]

[0009] One embodiment provides a catalyst for reforming methane-containing gas, comprising a porous carrier and an active metal supported within the porous carrier; the active metal comprising nickel; the porous carrier comprising calcium aluminate (CaAl2O4), a modified inorganic binder, and water; the modified inorganic binder comprising an aluminum compound and an alkaline earth metal compound, wherein the compressive strength of the porous carrier, as measured by a compressive strength meter, is 300 N or more.

[0010] Another embodiment provides a method for producing a catalyst for reforming the methane-containing gas.

[0011] Another embodiment provides a method for reforming a methane-containing gas using the methane-containing gas reforming catalyst. [Effects of the Invention]

[0012] When a catalyst for reforming a methane-containing gas, which is excellent in resistance to coke deposition while suppressing the catalyst sintering phenomenon according to one embodiment, is used, not only the deactivation of the catalyst is suppressed but also the mechanical strength of the catalyst can be maintained even after the reforming reaction of the methane-containing gas.

Brief Description of Drawings

[0013] [Figure 1a] It is a photograph taken immediately after tableting and curing of the molded product in Example 1. [Figure 1b] It is a photograph taken of the catalyst completed in Example 1. [Figure 2] It shows the methane conversion rate according to the reaction time of the catalyst when the steam / methane ratio was 2.5 in Evaluation Example 2. [Figure 3] It shows the methane conversion rate according to the reaction time of the catalyst when the steam / methane ratio was 1.25 in Evaluation Example 2. [Figure 4] It shows the activity reduction rate according to the reaction time of the catalyst when the steam / methane ratio was 1.25 in Evaluation Example 2. [Figure 5] It shows the catalyst strength according to the reaction time of the catalyst when the steam / methane ratio was 1.25 in Evaluation Example 2.

Mode for Carrying Out the Invention

[0014] (Definition of Terms) Throughout this specification, when a part includes a certain component, this means that, unless otherwise stated to the contrary, it can further include other components rather than excluding other components.

[0015] The term "step of ~(doing)" or "step of ~" used throughout this specification does not mean "step for ~".

[0016] Unless otherwise specifically defined in this specification, the particle size refers to the average particle size. Also, the particle size means the average particle size (D50) which is the diameter of the particles with a cumulative volume of 50% in the particle size distribution. The measurement of the average particle size (D50) is carried out by methods widely known to those skilled in the art. For example, it can be measured with a particle size analyzer, or it can also be measured from a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. As another method, it can be measured using a measuring device that utilizes the dynamic light-scattering method. After performing data analysis to count the number of particles for each particle size range, the average particle size (D50) value can then be calculated. Or it can be measured using the laser diffraction method. When measuring by the laser diffraction method, more specifically, after dispersing the particles to be measured in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (for example, MT3000 manufactured by Microtrac), irradiated with ultrasonic waves of about 28 kHz at an output of 60 W, and then the average particle size (D50) at the 50% criterion of the particle size distribution in the measuring device can be calculated.

[0017] Based on the above definitions, embodiments of the present invention will be described in detail. However, these are presented as examples and do not limit the present invention, which is only defined by the scope of the claims described below.

[0018] (Catalyst for reforming methane-containing gas) One embodiment provides a catalyst for reforming methane-containing gas, which includes a porous support and an active metal supported within the porous support; the active metal includes nickel; the porous support includes calcium aluminate (CaAl2O4), a modified inorganic binder, and water; the modified inorganic binder includes an aluminum compound and an alkaline earth metal compound, and the compressive strength measured by a compressive strength meter of the porous support is 300 N or more.

[0019] One embodiment corresponds to a catalyst for reforming methane-containing gas, which is applied under conditions of high temperature and excess steam to increase the methane conversion rate and hydrogen production rate.

[0020] In one embodiment, the catalyst for reforming methane-containing gas can exhibit excellent resistance to coke deposition while suppressing the catalytic sintering phenomenon. Therefore, using the catalyst for reforming methane-containing gas according to one embodiment not only suppresses catalyst deactivation after the reforming reaction of the methane-containing gas, but also maintains the catalyst's mechanical strength.

[0021] The following describes in detail one embodiment of a catalyst for reforming methane-containing gas.

[0022] [Porous carrier] The porous carrier comprises calcium aluminate (CaAl2O4), a modified inorganic binder, and water.

[0023] Calcium aluminate The porous support used is basically calcium aluminate (CaAl2O4), a basic substance that can suppress coke formation.

[0024] Modified inorganic binder As the porous carrier, an aluminum compound is used that can directly bond with the active metal while mediating the bonding between different calcium aluminates (CaAl2O4). As a result, the aluminum compound can function as both a binder and a carrier, and consequently, the dispersibility of nickel when it is supported on the porous carrier can be improved.

[0025] Furthermore, an alkaline earth metal compound was also introduced as a binder into the porous carrier. The alkaline earth metal compound can suppress the acidity of the acidic aluminum compound, ultimately forming a carrier with a structure in which the basic properties are maximized.

[0026] As will be described later, the aluminum compound and the alkaline earth metal compound are both modified forms derived from the "inorganic binder" used as the initial raw material, and are therefore referred to as "modified inorganic binders." However, organic binders are not used because they inhibit the increase in strength.

[0027] The aluminum compound may include gamma alumina, delta alumina, etha alumina, theta alumina, cerium aluminate, calcium aluminate, calcium-magnesium aluminate, nickel aluminate, or combinations thereof.

[0028] The alkaline earth metal compound may include magnesium oxide, magnesium aluminate, calcium-magnesium aluminate, or a combination thereof.

[0029] The weight ratio of the calcium aluminate (CaAl2O4) and the modified inorganic binder may be 100:1 to 100:30, 100:5 to 100:20, or 100:5 to 100:15. Within this range, the enhancement effect of the calcium aluminate (CaAl2O4) and the modified inorganic binder can be achieved.

[0030] water The water contained in the porous support not only dramatically increases the mechanical strength compared to the case without water, but also allows the support to maintain high strength even after the catalytic reaction.

[0031] The amount of water may be 1-10% by weight, 2-10% by weight, or 4-6% by weight relative to 100% by weight of the total amount of the porous carrier. Within this range, the mechanical strength of the porous carrier can be significantly improved.

[0032] Physical properties of porous carriers The compressive strength of the porous carrier, as measured by the compressive strength meter, may be 300 N or more, 310 N or more, or 320 N or more. There is no particular upper limit, but it may be 500 N or less, 450 N or less, or 430 N or less.

[0033] The BET specific surface area of ​​the porous carrier is 1 to 90 m². 2 / g, 1-50m 2 / g, 1-30m 2 / g, or 1-25m 2 / g is also acceptable.

[0034] The porous carrier has a pore volume of 12.0 to 30.0 cm³. 3 / g, 12.0~25.0cm 3 / g, or 12.0-20.0cm 3 / g is also acceptable.

[0035] In this way, the porous carrier can compensate for the low internal surface area of ​​the calcium aluminate and increase the pore volume while exhibiting high mechanical properties.

[0036] [Active metal] The active metal includes nickel as the main active metal, and the nickel may be present in an amount of 1 to 30% by weight, 5 to 20% by weight, or 10 to 15% by weight based on 100% by weight of the total amount of the catalyst.

[0037] If there is an excess of nickel, it will accumulate on the surface of the porous support instead of being drawn into it, resulting in low nickel dispersibility and a decrease in the durability of the catalyst.

[0038] On the other hand, because the internal surface area of ​​the calcium aluminate is low, when a high content of nickel is supported, partial aggregation of nickel metal occurs during the reforming reaction, and the methane conversion rate gradually decreases.

[0039] To prevent this, cerium, an auxiliary active metal, can be introduced in a form where it is bonded to the nickel via a bimetallic structure, thereby ensuring that the nickel dispersion is continuously maintained and preventing a decrease in activity during the reaction.

[0040] The nickel / cerium weight ratio can be 1 to 10, 3 to 9, or 4 to 8, and is preferably manufactured at a nickel / cerium weight ratio of 5 levels. The effects of increased nickel and cerium are observed within this range.

[0041] (Method for producing a catalyst for reforming methane-containing gas) One embodiment provides a method for producing a catalyst for reforming methane-containing gas, comprising the steps of: compressing a wet mixture of calcium aluminate (CaAl2O4) and an inorganic binder to produce a molded article; curing, drying, and calcining the molded article to obtain a porous carrier; supporting an activated metal precursor on the porous carrier; and, after drying and calcining the porous carrier with the activated metal precursor supported, reducing it under a hydrogen atmosphere to obtain a final catalyst, wherein the activated metal includes nickel; and the inorganic binder includes aluminum hydroxide and alkaline earth metal hydroxide.

[0042] One embodiment of the manufacturing method involves wet-mixing an inorganic binder containing aluminum hydroxide and alkaline earth metal hydroxide with a basic substance, calcium aluminate (CaAl2O4), and compression molding. After post-treatment, a high-strength carrier is produced through a moisture curing and calcination process, and then a catalyst in the form of an active metal is produced.

[0043] This may also be a method for producing a catalyst for reforming methane-containing gas as described in one embodiment above.

[0044] The following will describe in detail a manufacturing method according to one embodiment, omitting any explanations that overlap with those mentioned above.

[0045] [Manufacturing process for carriers] Pre-treatment process As the calcium aluminate (CaAl2O4), calcium aluminate (CaAl2O4) powder having an average particle size (D50) of 100-500 μm, 200-500 μm, or 300-500 μm can be used, which has been heat-treated at a temperature range of 500-1,200°C, 600-1,000°C, or 700-900°C.

[0046] If the average particle size of the calcium aluminate (CaAl2O4) is too small, the interparticle cohesive force will weaken during the compression molding process described later, potentially resulting in a lower strength for the molded product. Conversely, if the average particle size of the calcium aluminate (CaAl2O4) is too large, the pore volume of the molded product will decrease, increasing its density and making it difficult to use as a carrier.

[0047] The inorganic binder includes aluminum hydroxide (aluminum hydroxide) and alkaline earth metal hydroxide.

[0048] The inorganic binders used may include, but are not limited to, aluminum hydroxide, boehmite, pseudoboehmite, aluminum stearate, alumina, magnesium hydroxide, magnesium oxide, magnesium silicate, silicate, silica, silica-alumina, titania, and zirconia.

[0049] For example, the inorganic binder may be an aluminum-containing binder that has good binding affinity to calcium aluminate and can function as a carrier in addition to being a binder, or it may be an alkali-aluminum hybrid binder that can exhibit basic properties.

[0050] The weight ratio of the calcium aluminate (CaAl2O4) to the inorganic binder may be 100:5 to 100:30, or 100:5 to 100:15. Within this range, the enhancement effect of the calcium aluminate (CaAl2O4) and the inorganic binder can be achieved.

[0051] The inorganic binder can be one with an average particle size (D50) of 100-500 μm, 200-500 μm, or 300-500 μm, similar to the calcium aluminate (CaAl2O4).

[0052] If the average particle size (D50) of the inorganic binder differs from that of the calcium aluminate (CaAl2O4), layer separation may occur during mixing, potentially leading to localized low uniformity within the molded body during compression molding.

[0053] Wet mixing process The wet mixture of calcium aluminate (CaAl2O4) and inorganic binder may contain 1 to 10 parts by weight, 2 to 10 parts by weight, or 4 to 6 parts by weight of water based on 100 parts by weight of the total amount of calcium aluminate (CaAl2O4) and inorganic binder.

[0054] If there is insufficient water during this process, the inter-powder bonding force will be very weak during the compression molding process described later, making it difficult to achieve sufficient carrier strength. Conversely, if there is too much water, powder coagulation will occur, making continuous production impossible when fed into a compression molding machine, and potentially resulting in unsuitable strength and shape of the final molded product.

[0055] Compression molding process The wet mixture of calcium aluminate (CaAl2O4) and inorganic binder is 400-800 kg / cm³. 2 It can be compressed by that pressure.

[0056] In this process, molded articles with the desired form, density, and strength can be manufactured. The molded articles can be manufactured in various forms and sizes, such as cylinder type and hole type, and there are no limitations on this. Furthermore, since the density of the carrier is determined according to the tableting pressure, carriers with the desired properties can be manufactured based on numerous experimental results.

[0057] Curing process The molded product can be cured for 1 to 12 hours, or 4 to 8 hours.

[0058] This process increases the strength of the molded product. If the curing time is insufficient, the process ends before the molded product reaches sufficient strength, and therefore no increase in strength can be expected. On the other hand, if the curing time is too long, it can induce a decrease in the surface area and pore volume of the carrier itself, potentially reducing the maximum amount of active metal that can be supported.

[0059] Drying and firing process The cured molded product can be dried at a temperature range of 80-120°C or 90-110°C and fired at a temperature range of 400-1,200°C, 600-1,100°C, or 800-1,000°C.

[0060] In this process, the bonding strength between the individual substances within the cured molded product can be increased. Furthermore, the binder within the cured molded product has not yet been modified and can be transformed into an oxide form through the firing process.

[0061] If the firing temperature is too low, the aluminum hydroxide in the cured molded product may not be completely transformed into an oxide form, making it difficult to remove organic matter from the cured molded product. On the other hand, if the firing temperature is too high, the crystalline phase of the aluminum hydroxide in the cured molded product may change to an alpha-alumina form, resulting in a very low specific surface area, which may prevent it from functioning as a carrier.

[0062] When this process is carried out, the crystalline phase of the alumina, which is the final product of aluminum hydroxide, can be produced as a gamma, delta, eta, or theta phase that appears in the heat treatment temperature range.

[0063] [Supporting process] The activated metal precursor can be supported on the porous carrier obtained through the curing, drying, and firing processes of the molded product using a spray drying method.

[0064] The nickel precursor used here can be one of the following: nickel nitrate hydrate, nickel chloride hydrate, nickel acetate hydrate, or nickel sulfate hydrate. The cerium precursor can be one of the following: cerium nitrate hydrate, cerium chloride hydrate, cerium acetate hydrate, cerium sulfate hydrate, or cerium oxalate hydrate.

[0065] For example, compounds having the same anionic form can be sequentially or mixed to produce a supported solution which can then be used.

[0066] The activated metal precursor can be produced by dissolving an amount equal to the pore volume of the porous carrier in a solvent such as deionized water or a dihydric alcohol (ethanol, ethylene glycol, etc.) and supporting it on the carrier using a dipping method or a spray-coating method. For example, it can be produced by a spray-coating method.

[0067] The porous carrier, with the activated metal supported on it, can be dried in a temperature range of 80-180°C, 90-150°C, or 100-130°C, and then fired in a temperature range of 400-1,000°C, 500-900°C, or 500-800°C.

[0068] In this process, water and anions derived from the active metal precursor can be removed, and the active metal precursor (e.g., nickel compounds, cerium compounds, etc.) may be converted into active metal oxides. The calcination temperature is common knowledge and can be performed within an appropriate range, so no further detailed explanation will be given. However, the calcination can be performed at a temperature above the reforming reaction temperature of the methane-containing gas to prevent deformation of the active metal in the catalyst during the reforming reaction of the methane-containing gas.

[0069] After drying and firing, the material can be reduced in a temperature range of 400-1,000°C, 500-900°C, or 500-800°C.

[0070] In this process, the activated metal oxide can be rapidly reduced. However, if the temperature is too low during the reduction process, the activated metal oxide may not be completely reduced, and if the temperature is too high, aggregation and sintering of the activated metal particles may occur, which can reduce the number of active sites.

[0071] The reduction process can be carried out in a step manner, for example, by heating the temperature to 600°C in an air or nitrogen atmosphere and then injecting hydrogen gas.

[0072] When a catalyst contains two or more active metal species, exposing them to hydrogen gas at high temperatures immediately, as in the reduction method described above, allows the active metal species to be instantaneously produced in an alloy form. However, when reduction is carried out by gradually raising the temperature from room temperature in a hydrogen atmosphere, each metal is reduced according to its own oxygen desorption temperature, making it difficult for them to form an alloy.

[0073] (Method for reforming methane-containing gas) Another embodiment provides a method for reforming a methane-containing gas using the methane-containing gas reforming catalyst according to the aforementioned embodiment.

[0074] Because this method utilizes the aforementioned catalyst for reforming methane-containing gases, it not only suppresses catalyst deactivation after the reforming reaction of methane-containing gases but also maintains the catalyst's mechanical strength. As a result, a high hydrogen conversion rate can be achieved.

[0075] The following explanation will omit any repetition of the content mentioned above and will describe in detail a method for reforming methane-containing gas according to one embodiment.

[0076] The methane-containing gas may be a methane-containing gas in which steam / natural gas or biogas (usually referred to as the S / C ratio) is mixed at a volume ratio of 1.25 to 2.5.

[0077] For the reforming reaction of the methane-containing gas, after introducing the catalyst into the reactor, a mixed gas of steam and the methane-containing gas can be subjected to a gas-phase reaction to produce hydrogen.

[0078] The reforming reaction of the methane-containing gas can be carried out under the condition of a gas hourly space velocity of 1,000 to 30,000 h -1 .

[0079] However, the above is an example. The higher the gas hourly space velocity, the proportionally higher the hydrogen production amount. Since the optimal value can be arbitrarily adjusted according to the reactor volume and the amount of catalyst, it is not limited to a specific value within the above range.

[0080] The reforming reaction of the methane-containing gas can be carried out in a temperature range of 700 to 900 °C.

[0081] If the reforming reaction temperature of the methane-containing gas is too low, a sufficient reforming reaction cannot proceed, and only a very small amount of hydrogen can be obtained. On the other hand, if the reforming reaction temperature of the methane-containing gas is too high, side reactions such as aggregation and sintering of the active metal of the catalyst introduced into the reactor, coke formation, and cracking reaction may occur, and problems may occur in the catalyst durability.

[0082] The reactor is not particularly limited, but a fixed-bed catalytic reactor in which the reactor is filled with a catalyst can be used. Also, since the dehydrogenation reaction is an endothermic reaction, it is important for the reactor to always maintain adiabatic. The reforming reaction process of the present invention can proceed with the reaction temperature, pressure, and gas hourly space velocity, which are reaction conditions, maintained within an appropriate range.

[0083] The following description will refer to embodiments of the present invention, but these embodiments are for illustrative purposes only and the scope of the present invention is not limited to them.

[0084] Example 1 (1) Manufacturing of porous carriers As a carrier material, calcium aluminate with an average particle size (D50) of 450 μm was prepared by heat treatment at 800°C.

[0085] Aluminum hydroxide was prepared as the first inorganic binder, with an average particle size (D50) of 450 μm.

[0086] The prepared carrier material, calcium aluminate, and the first inorganic binder, aluminum hydroxide, were mixed at high speed with deionized water using a mixer.

[0087] Here, the carrier material / total binder ratio was adjusted to 20 according to Table 1 below, and the amount of deionized water was adjusted to 5% by weight of the total mixture containing 100% by weight.

[0088] Subsequently, a compression tableting machine was used to apply a tableting pressure of 600 kg / cm². 2 The following adjustments were made, and the molded product was formed into a cylindrical shape with a diameter of 5 mm. Subsequently, the molded product was placed on the mesh inside a curing machine filled with water at the bottom, the top cap was closed, and it was left to stand at 80 degrees Celsius for 8 hours. After moisture curing was complete, the molded product was dried in a 100°C dryer for 12 hours, and then heat-treated at 900°C for 6 hours to obtain a porous carrier.

[0089] Figure 1a is a photograph taken immediately after tableting and curing of the molded product in Example 1, and Figure 1b is a photograph taken of the catalyst after manufacturing was completed in Example 1.

[0090] (2) Production of catalysts The porous support was impregnated with nickel nitrate (Ni(NO3)2·6H2O) and cerium nitrate (Ce(NO3)3·6H2O) dissolved in deionized water by spray drying. After impregnation, the support underwent an aging process for approximately 1 hour to allow the metal solution to be sufficiently distributed throughout the support. After drying at 120°C for 12 hours to completely remove moisture from the catalyst, the metal was immobilized by a heat treatment process at 700°C for 6 hours in an air atmosphere. Subsequently, the heat-treated catalyst was heated to 600°C in an air atmosphere, purged with nitrogen for 5 minutes, and then rapidly reduced while flowing hydrogen gas to produce the catalyst.

[0091] The catalyst produced by this method contained 10.0% by weight of nickel and 2.0% by weight of cerium per 100% by weight of the total catalyst amount, and the nickel-cerium was uniformly distributed within the support.

[0092] Example 2 (1) Manufacturing of porous carriers As a support material, calcium aluminate with an average particle size (D50) of 450 μm was prepared by heat treatment at 800°C.

[0093] Aluminum hydroxide was prepared as the first inorganic binder, and magnesium hydroxide as the second inorganic binder, with each having an average particle size (D50) of 450 μm.

[0094] The prepared carrier material, calcium aluminate, the first inorganic binder, and the second inorganic binder, aluminum hydroxide, were mixed at high speed with deionized water using a mixer.

[0095] Here, the carrier material / total binder ratio was set to 20 and the first inorganic binder / second inorganic binder ratio to 15 according to Table 1 below, and the amount of deionized water was adjusted to 5% by weight of the total mixture containing 100% by weight.

[0096] Subsequently, a compression tableting machine was used to apply a tableting pressure of 600 kg / cm². 2The following adjustments were made, and the molded product was formed into a cylindrical shape with a diameter of 5 mm. Subsequently, the molded product was placed on the mesh inside a curing machine filled with water at the bottom, the top cap was closed, and it was left to stand at 80 degrees Celsius for 8 hours. After moisture curing was complete, the molded product was dried in a 100°C dryer for 12 hours, and then heat-treated at 900°C for 6 hours to obtain a porous carrier.

[0097] (2) Production of catalysts The catalyst was produced in the same manner as in Example 1, except that the porous support was used.

[0098] Example 3 The catalyst was prepared in the same manner as in Example 2, except that cerium, an auxiliary metal, was not used, as shown in Table 2 below.

[0099] Example 4 The catalyst was manufactured in the same manner as in Example 2, except that the carrier material / total binder ratio was changed to 5 according to Table 1 below.

[0100] Example 5 The catalyst was manufactured in the same manner as in Example 2, except that the carrier material / total binder ratio was changed to 30 according to Table 1 below.

[0101] Example 6 The catalyst was manufactured in the same manner as in Example 2, except that the ratio of the first inorganic binder to the second inorganic binder during catalyst production was changed to 5, as shown in Table 1 below.

[0102] Comparative Example 1 A porous carrier and catalyst were manufactured in the same manner as in Example 2, except that the curing process during carrier molding was omitted.

[0103] Comparative Example 2 A porous carrier and catalyst were manufactured in the same manner as in Example 1, except that no inorganic binder was used during carrier molding.

[0104] Comparative Example 3 A porous support and catalyst were manufactured in the same manner as in Example 2, except that silica powder was used as the first inorganic binder during support molding.

[0105] Comparative Example 4 A porous support was manufactured in the same manner as in Example 2, except that an organic binder, PVA (polyvinyl alcohol), was further mixed during the support molding process. However, the shape of the support collapsed during the curing process using this porous support, resulting in failure to manufacture the catalyst.

[0106] Comparative Example 5 A porous support and catalyst were manufactured in the same manner as in Example 1, except that alumina powder was used instead of calcium aluminate as the support material.

[0107] Comparative Example 6 A porous carrier and catalyst were manufactured in the same manner as in Example 1, except that alumina powder was used instead of calcium aluminate as the carrier material and the curing process was omitted.

[0108] The porous support compositions for the above examples and comparative examples are shown in Table 1, and the active metal compositions are shown in Table 2.

[0109] [Table 1]

[0110] [Table 2]

[0111] Evaluation Example 1: Physical properties before obtaining the porous carrier after compression molding, and physical properties after final acquisition. The physical properties of the porous carrier after compression molding and the final yield after post-treatment in the examples and comparative examples were evaluated using the following methods and are shown in Table 3.

[0112] (1) Physical properties (compressive strength) before and after obtaining a porous carrier after compression molding Compression strength measurement equipment: Compression strength meter The compressive strength of the catalyst was measured using a hardness tester (Pharmatron MT-50). The cross-section of the catalyst sample was placed in contact with the jig of the hardness tester, and the strength in the lateral direction was measured. The movement speed of the jig of the hardness tester was set to 2 mm / sec, and the instantaneous maximum stress at which the catalyst broke was calculated.

[0113] (2) Physical properties of porous carriers (specific surface area and pore volume) Specific surface area / pore volume measurement equipment: BET N2 physisorption Nitrogen adsorption isotherms were measured at -196°C using a Micromeritics Tristar 3000 volumetric adsorption analyzer. All samples were degassed at 300°C in a degassing station before adsorption measurements. The Brunauer-Emmett-Teller (BET) equation was used to calculate the specific surface area from adsorption data obtained at P / P0 between 0.05 and 0.2. The total volume of micropores and mesopores was calculated using the amount of adsorbed nitrogen at P / P0 = 0.95, assuming that adsorption on the external surface was negligible compared to adsorption in the pores.

[0114] [Table 3]

[0115] Referring to Tables 2 and 3 above, the examples and comparative examples manufactured using the same process are as follows:

[0116] In Example 1, which uses an inorganic binder, the specific surface area and pore volume are expected to increase, leading to improved catalytic efficiency, compared to Comparative Example 2, which does not use any inorganic binder.

[0117] In Example 2, where aluminum hydroxide was used as the first inorganic binder, it can be seen that the pore volume increased and the mechanical properties (compressive strength) was significantly improved compared to Comparative Example 3, which used silica.

[0118] In Example 2, where no organic binder was used, the shape of the porous support was maintained, whereas in Comparative Example 4, where an organic binder was used, the shape of the porous support was not maintained and actually collapsed.

[0119] The following is a comparison of the examples and comparative examples with the same composition.

[0120] In Example 2, which underwent curing and firing processes, it can be seen that the pore volume increased and the mechanical properties (compressive strength) was significantly improved compared to Comparative Example 1, in which the curing process was omitted.

[0121] The following is a comparison of the examples and comparative examples where calcium aluminate was used or not.

[0122] In Comparative Examples 5 and 6, where alumina was used instead of calcium aluminate, the specific surface area increased significantly compared to Example 1, where calcium aluminate was used, to the point of impairing the mechanical properties (compressive strength).

[0123] Evaluation Example 2: Reforming reaction of methane-containing gas Using the catalysts produced in the examples and comparative examples, the reforming reaction of methane-containing gas was carried out at a reaction temperature of 800°C, a space velocity (SV) of 2,000 / hr, and a water vapor / methane volume ratio of 2.5 or 1.25. The evaluation results for each water vapor / methane volume ratio condition are shown in Tables 4 and 5 below and are illustrated in Figures 2 to 5.

[0124] (1) Catalytic reactions: The specific catalytic reactions are as follows.

[0125] To measure catalytic activity, a mixed gas of methane and hydrogen was used, and the reactor was evaluated using a fixed-bed reaction system. 1.57 g of catalyst was packed into a tubular reactor, and before the reaction, hydrogen gas was continuously flowed at a constant rate of 30 cc / min to remove oxygen species from the catalyst surface, and the catalyst was reduced at 800°C for 1 hour. Subsequently, the reactor temperature was maintained at the reaction temperature of 800°C, and a mixed gas of methane and hydrogen, the raw materials used in the reaction, was continuously supplied to the reactor at a constant 1:1 volume ratio, with a gas space velocity of 2000 hF. -1 It was fixed to a constant value.

[0126] Furthermore, to suppress the generation of coke during the catalytic reaction, steam / methane was injected at a ratio of 2.5 (Table 4 and Figure 2) or 1.25 (Table 5 and Figures 3-5). The reaction pressure was kept constant at 1.0 atmosphere using a pressure regulator. The substances produced after the reaction were transferred to gas chromatography (GC) via an injection line wrapped with a hot wire, and quantitative analysis was performed using a flame ionization detector (FID) and a thermal conductivity detector (TCD).

[0127] (2) Methane conversion rate by water vapor / methane volume ratio and reaction time: The conversion rate of methane relative to the reactants was calculated using the following formula 1, and the activity of the catalyst was compared. [Formula 1] Methane conversion rate (%) = [Number of moles of methane before reaction - Number of moles of methane after reaction] / [Number of moles of methane before reaction] × 100

[0128] (3) Coke deposition amount by water vapor / methane volume ratio: The amount of coke deposited on the catalyst after 150 hours of reaction was measured.

[0129] (4) Catalyst strength and rate of change of strength after 150 hours of reaction by water vapor / methane volume ratio: The compressive strength of the catalyst after 150 hours of reaction was measured using a compressive strength meter, and the rate of change relative to the compressive strength of the catalyst before the reaction was calculated.

[0130] [Table 4]

[0131] [Table 5]

[0132] Tables 4 and 5, and Figures 2-5 show that both the examples and comparative examples exhibit a high methane conversion rate of approximately 98% or more even after 150 hours of reaction under conditions where the water vapor / methane ratio is high at 2.5. However, when the water vapor / methane ratio is low at 1.25, the difference in catalyst strength as well as the rate of decrease in post-reaction activity is significantly affected by the difference in the carrier manufacturing method.

[0133] In Examples 1-6, porous carriers were produced according to the carrier raw material / total binder ratio, and compared to Comparative Examples 1-6, they generally exhibited higher activity, coke resistance, and a lower rate of strength change simultaneously.

[0134] Specifically, when each example is distinguished from the comparative example, they are as follows.

[0135] First, in Example 2 and Comparative Example 1, catalysts were produced by changing the manufacturing method depending on whether or not moisture curing was performed during the manufacturing of the porous support.

[0136] Compared to Comparative Example 1, in which the curing process was not introduced, the compressive strength of the porous carrier in Example 2, in which the curing process was introduced, increased dramatically. Furthermore, in the compressive strength of the catalyst after activity evaluation, Comparative Example 1, in which the curing process was not introduced, experienced a strength decrease of approximately 50%, whereas Example 2, in which the curing process was introduced, showed almost no change in strength.

[0137] Example 2 and Comparative Example 2 show catalysts produced by varying the manufacturing method depending on whether or not an inorganic binder was used.

[0138] Comparative Example 2 shows a similar rate of activity reduction compared to Example 2, but the specific surface area of ​​the final porous support is significantly lower, resulting in poor dispersion of nickel metal and a lower methane conversion rate.

[0139] Examples 1, Comparative Examples 5 and 6 show catalysts produced by changing the manufacturing method according to differences in the carrier raw materials.

[0140] After moisture curing, it can be seen that the compressive strength of Example 1 is approximately 2.5 times higher than that of Comparative Example 5.

[0141] After evaluating the reaction following catalyst production using each support, Example 1, which used a basic support, showed stronger activity reduction rates, coke formation rates, and post-reaction catalyst strength reduction rates compared to Comparative Examples 5 and 6, which used alumina, an acidic support.

[0142] This study reveals that basic support structures with a spinel structure are more effective at moisture curing than pure alumina structures, and that, unlike alumina supports with abundant acid sites, support structures with basic properties have an advantageous effect on catalytic reactions and catalyst durability.

[0143] Examples 1 and 2 demonstrate the production of catalysts by varying the manufacturing method depending on the combination of inorganic binders.

[0144] Under relatively mild reaction conditions with a high steam ratio, such as S / C = 2.5, neither catalyst shows any performance change even during long-term reactions.

[0145] However, under the harsh conditions of a low steam ratio of S / C = 1.25, Example 2 showed a lower rate of activity reduction and coke deposition after 150 hours of reaction compared to Example 1. This indicates that, compared to Example 1, which used alumina alone as an inorganic binder, Example 2, which used alumina surface-modified with magnesium, a basic substance, suppressed side reactions such as methane cracking due to the acid sites inherent in alumina itself, reducing the coke formation rate and thereby suppressing performance degradation.

[0146] In Examples 2 and 3, catalysts were produced by varying the manufacturing method depending on whether or not cerium, an auxiliary metal, was added.

[0147] Compared to Example 3, in which cerium was not added, the degree of nickel dispersion within the catalyst in Example 2, in which cerium was added, was approximately 50% higher, indicating that it has an advantage in initial reaction activity.

[0148] In short, the methane-containing gas reforming catalysts of one embodiment, represented by Examples 1 to 6, exhibit excellent resistance to coke deposition while suppressing catalytic sintering phenomena.

[0149] Therefore, by using the catalyst for reforming methane-containing gas according to one embodiment, not only is the deactivation of the catalyst suppressed after the reforming reaction of the methane-containing gas, but the mechanical strength of the catalyst can also be maintained.

[0150] Although preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the attached drawings, and these also naturally fall within the scope of the present invention.

Claims

1. A porous carrier and an active metal supported within the porous carrier; The aforementioned active metal is Contains nickel; The porous carrier is Calcium aluminate (CaAl ２ O ４ ), Modified inorganic binders, and Contains water; The modified inorganic binder is, Aluminum compounds, and Contains alkaline earth metal compounds, The compressive strength of the porous carrier, as measured by a compressive strength meter, is 300 N or more. A catalyst for reforming methane-containing gases.

2. With respect to 100% by weight of the total amount of the porous carrier, The water contains 1 to 10% by weight. The catalyst for reforming methane-containing gas according to claim 1.

3. The aforementioned calcium aluminate (CaAl ２ O ４ The weight ratio of ) and modified inorganic binder is, The ratio is between 100:1 and 100:

30. The catalyst for reforming methane-containing gas according to claim 1.

4. The aforementioned aluminum compound, This includes gamma alumina, delta alumina, etha alumina, theta alumina, cerium aluminate, calcium aluminate, calcium magnesium aluminate, nickel aluminate, or combinations thereof. The aforementioned alkaline earth metal compound is Magnesium oxide, magnesium aluminate, calcium magnesium aluminate, or combinations thereof, The catalyst for reforming methane-containing gas according to claim 1.

5. The BET specific surface area of ​​the porous carrier is 1 to 90 m². ２ / g is The catalyst for reforming methane-containing gas according to claim 1.

6. The porous carrier has a pore volume of 12.0 to 30.0 cm³. ３ / g is The catalyst for reforming methane-containing gas according to claim 1.

7. With respect to 100% by weight of the total amount of the catalyst, The aforementioned nickel is present in an amount of 1 to 30% by weight. The catalyst for reforming methane-containing gas according to claim 1.

8. The active metal further comprises cerium. The catalyst for reforming methane-containing gas according to claim 1.

9. The weight ratio of nickel / cerium is 1 to 10. The catalyst for reforming methane-containing gas according to claim 8.

10. Calcium aluminate (CaAl ２ O ４ A step of compressing a wet mixture of ) and an inorganic binder to produce a molded article; A step of curing, drying, and firing the molded product to obtain a porous carrier; A step of supporting an active metal precursor on the porous carrier; The porous support is dried and calcined while an activated metal precursor is supported on it, and then reduced under a hydrogen atmosphere to obtain the final catalyst. The aforementioned active metal is Contains nickel; The inorganic binder is, Aluminum hydroxide, and Contains alkaline earth metal hydroxides, A method for producing a catalyst for reforming methane-containing gases.

11. The calcium aluminate (CaAl ２ O ４ ) is calcium aluminate (CaAl ２ O ４ powder with an average particle size (D50) of 100 to 500 μm heat-treated in a temperature range of 500 to 1,200°C. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

12. The inorganic binder has an average particle size (D50) of 100 to 500 μm. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

13. The aforementioned calcium aluminate (CaAl ２ O ４ ) and a wet mixture of inorganic binders, The aforementioned calcium aluminate (CaAl ２ O ４ Based on a total amount of 100 parts by weight of ) and inorganic binder, it contains 1 to 10 parts by weight of water. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

14. The aforementioned calcium aluminate (CaAl ２ O ４ The wet mixture of ) and inorganic binder is 400-800 kg / cm³. ２ Compress with the pressure of A method for producing a catalyst for reforming methane-containing gas according to claim 10.

15. The curing of the molded product is carried out for 1 to 12 hours. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

16. The cured molded product is dried at a temperature range of 80 to 120°C and then fired at a temperature range of 400 to 1,200°C. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

17. The activated metal is supported on the porous carrier using a spray drying method. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

18. The porous carrier, with the activated metal supported on it, is dried in a temperature range of 80 to 180°C and then calcined in a temperature range of 400 to 1,000°C. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

19. After the drying and firing process, the material is reduced at a temperature range of 400 to 1,000°C. A method for producing a catalyst for reforming methane-containing gas according to claim 10.

20. A method for reforming a methane-containing gas, using a methane-containing gas reforming catalyst described in any one of claims 1 to 9.

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