WO2022225200A1

WO2022225200A1 - Heterometallic catalyst for non-oxidative direct conversion of methane and method for preparing same

Info

Publication number: WO2022225200A1
Application number: PCT/KR2022/003984
Authority: WO
Inventors: 한승주; 게브레키단 게브레요하네스세가이; 김용태; 김석기; 김현우; 신정호; 이성우
Original assignee: 한국화학연구원
Priority date: 2021-04-21
Filing date: 2022-03-22
Publication date: 2022-10-27
Also published as: KR20220145455A

Abstract

The present invention relates to a heterometallic catalyst for non-oxidative direct conversion of methane and a method for preparing same and, more specifically, to a catalyst for non-oxidative direct conversion of methane and a method for preparing same, in which, in the preparation of hydrocarbon through non-oxidative direct conversion of methane, by using a highly crystalline catalyst which is optimized for direct conversion of methane and includes iron (Fe) and platinum (Pt) components, the formation of cokes on the surface of the catalyst is minimized, and methane conversion reactivity can be maximized.

Description

Dissimilar metal catalyst for non-oxidative direct conversion of methane and method for preparing same

The present invention relates to a heterometallic catalyst for non-oxidative direct conversion of methane and a method for preparing the same, and more particularly, to a catalyst for non-oxidative direct conversion of methane useful for non-oxidative direct conversion of methane to produce hydrocarbons, and a method for preparing the same is about

Recently, efforts to convert methane (CH ₄ ) obtainable from natural gas, sail gas, etc. into high value-added products such as transportation fuels or chemical raw materials have been steadily made. A representative example of the high value-added product that can be obtained from methane is light olefin (ethylene, propylene, butylene, etc.) (Methanol to Olefins) technology and FTO (Fischer-Tropsch to Olefins) technology, which directly produces light olefins from syngas, are known as the most feasible technologies. However, in the case of this technology for producing high value-added products via synthesis gas, H2 or CO is additionally required to remove O atoms from CO, which reduces the utilization efficiency of H or C atoms in the entire process. results in

Therefore, a new technology capable of directly converting methane into a high value-added product without going through syngas is required. In order to directly convert methane into a high-addition product, it is necessary to first activate methane by cleaving the CH bond (434 kJ/mol) that is strongly formed in methane. Oxidative Coupling of Methane (OCM) technology has been actively studied. However, in the OCM reaction, thermodynamically stable H ₂ O and CO ₂ are formed in large amounts due to the intense reactivity of O ₂ , and thus, the utilization efficiency of H or C atoms is still pointed out as a problem.

In order to solve this problem, a technology for producing ethylene and aromatic compounds by direct conversion of methane under anaerobic or anoxic conditions has recently been developed. It is essential. However, according to the research results so far, the problem of a sudden decrease in catalytic activity due to carbon (coke) deposition in the catalyst under conditions of high temperature and high pressure has emerged as a key issue (refer to Non-Patent Documents 0001 and 0002).

Accordingly, in US Patent Publication No. 2014-0336432, in the non-oxidative conversion method of methane in which a methane-containing raw material is reacted, one of C, N and O to suppress carbon (coke) deposition of the catalyst under high temperature/high pressure conditions. A catalyst doped with a metal element was used in the material lattice of an amorphous molten state formed by bonding with Si or more, and in US Patent Publication No. 2016-0362351, at least one of C, N and O and B, Al, Si, A non-oxidative coupling method of methane has been disclosed in which a catalyst doped with a chemically active metal is applied to an amorphous molten material lattice formed by bonding at least one of Ti, Zr, and Ge.

However, the catalyst disclosed in the above document simply shows the result of suppressing coke production and improving the catalytic reaction rate compared to the conventional catalyst for non-oxidative direct conversion of methane prepared by sol-gel or impregnation method, and is suitable for non-oxidative direct conversion of methane. No method for preparing an optimized catalyst or manufacturing conditions are presented.

On the other hand, when the reaction conditions in the non-oxidative conversion reaction of methane are not appropriate, as the conversion rate of methane increases, the selectivity of the coke is also high, and there is a problem in that the selectivity of hydrocarbon compounds, the production rate, etc. are deteriorated. Therefore, in order to maximize a high catalytic reaction rate and at the same time minimize coke generation, there remains a task of configuring a reactor including a catalyst capable of additionally radical reaction.

The main object of the present invention is to solve the above-mentioned problems, in the non-oxidative direct conversion of methane, by optimizing the active phase and carrier properties of the heterogeneous metal catalyst to maximize the catalytic reaction rate and at the same time suppress side reactions to produce coke An object of the present invention is to provide a catalyst for non-oxidative direct conversion of methane capable of minimizing (cokes) production and improving the deactivation rate of the catalyst, and a methane conversion method using the same.

In order to achieve the above object, an embodiment of the present invention provides a method for preparing a catalyst for non-oxidative direct conversion of methane, comprising the steps of: (a) impregnating a catalyst carrier compound with a platinum (Pt) precursor; (b) drying and calcining the impregnated material; (c) mixing the calcined impregnated material with fayalite, followed by pulverization in an inert atmosphere using a ball mill; (d) introducing the pulverized mixture into a reactor and then melting to obtain a melt; And (e) provides a method for preparing a catalyst for non-oxidative direct conversion of methane comprising the step of solidifying the obtained melt.

In a preferred embodiment of the present invention, step (a) may be characterized in that 0.1 to 2 parts by weight of a platinum (Pt) precursor is impregnated with respect to 100 parts by weight of the catalyst carrier compound.

In a preferred embodiment of the present invention, the sintering in step (b) may be characterized in that it is heated to 300 °C to 900 °C at a temperature increase rate of 1 °C/min or more.

In a preferred embodiment of the present invention, step (c) may be characterized in that 0.1 to 4 parts by weight of fayalite is impregnated with respect to 100 parts by weight of the catalyst carrier compound.

In a preferred embodiment of the present invention, the step (c) may be characterized in that the grinding is performed at a speed of 100 rpm to 300 rpm for 4 to 18 hours using a ball mill.

In a preferred embodiment of the present invention, the melting of step (d) may be characterized in that it is performed by heating from 1,200 °C to 2,000 °C at a temperature increase rate of 6 °C/min or more.

In a preferred embodiment of the present invention, the catalyst carrier compound may be at least one selected from the group consisting of silica, alumina, titania, zirconia and silicon carbide.

In addition, another embodiment of the present invention is prepared by the method for preparing the catalyst for non-oxidative direct conversion of methane, and includes a catalyst carrier including the catalyst carrier compound, and has a specific surface area of 5 m ² /g or less. It provides a catalyst for non-oxidative direct conversion of methane, characterized in that it has a highly crystalline structure.

In a preferred embodiment of the present invention, the amount of iron supported may be 0.1 to 2.0 wt% based on the total weight of the catalyst.

In a preferred embodiment of the present invention, the supported amount of platinum (Pt) may be 0.1 to 2.0 wt% based on the total weight of the catalyst.

In a preferred embodiment of the present invention, the catalyst carrier may be characterized in that it is in a molten crystalline state.

According to the present invention, it is possible to maximize the activity for methane in the non-oxidative direct conversion reaction of methane and at the same time minimize the coke generation and provide a high yield for the aromatic hydrocarbon product.

1 is a schematic diagram of a method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention.

2 is a flowchart of a method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention.

3 is a graph showing the correlation of coke selectivity with respect to methane conversion in a catalyst for methane conversion reaction.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is those well known and commonly used in the art.

In the present specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present invention in one aspect, (a) impregnating a platinum (Pt) precursor in a catalyst carrier compound; (b) drying and calcining the impregnated material; (c) mixing the calcined impregnated material with fayalite, followed by pulverization in an inert atmosphere using a ball mill; (d) introducing the pulverized mixture into a reactor and then melting to obtain a melt; and (e) solidifying the obtained melt. It relates to a method for preparing a catalyst for non-oxidative direct conversion of methane.

More specifically, the method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention maximizes the catalytic reaction rate by including a heterogeneous metal catalyst, and at the same time increases the uniformity and dispersibility of the catalyst through atomization before the melting step, The catalyst is reduced due to the heat generated during the atomization process and the catalyst is sintered to prevent deterioration of the activity of the prepared catalyst. By including the atomization step and the melting step under certain conditions, the catalyst reaction rate into the product is maximized and coke (coke) ) production and can easily provide a catalyst for non-oxidative direct conversion of methane having stable catalytic performance even in long-term operation.

Hereinafter, a method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention will be described in more detail with reference to the accompanying drawings.

1 and 2 are schematic diagrams and flow charts of a method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention, respectively.

In the method for preparing a catalyst for non-oxidative direct conversion of methane according to the present invention, a platinum (Pt) precursor is first impregnated with a catalyst carrier compound [step (a)].

As an example, in step (a), the platinum precursor is dissolved in distilled water to prepare a platinum precursor solution, and then the catalyst carrier compound is dispersed to prepare an impregnated material.

In this case, as a solvent for preparing the platinum precursor solution, a polar organic solvent such as alcohol or acetone may be used instead of distilled water, or a mixed solvent including distilled water and one or more polar organic solvents may be used.

As an example, when preparing a platinum precursor solution using 30 to 60 ml of the solvent, the weight of the platinum precursor is preferably 0.05 to 0.2 g.

In addition, the catalyst carrier compound for forming the catalyst carrier is silica (SiO ₂ ), alumina (Al ₂ O ₃ ), ceria (CeO ₂ ), titania (TiO ₂ ), zirconia (ZrO ₂ ), activated carbon (Activated carbon) , AC), silicon carbide (SiC), and may include at least one selected from the group consisting of silicon nitride (SiN), preferably silica, alumina, titania, zirconia or silicon carbide may be used, and more Preferably, it may be silica.

In addition, when the catalyst carrier compound is silica, specifically, it is preferably quartz.

In the manufacturing method according to the present invention, the platinum precursor is platinum hexachloride (H ₂ PtCl ₆ ), platinum ammonium chloride (Pt(NH ₃ ) ₄ Cl ₂ ) or platinum ammonium nitrate (Pt(NH ₃ ) ₄ ( NO ₃ ) ₂ ) may be used, and preferably platinum ammonium nitrate (Pt(NH ₃ ) ₄ (NO ₃ ) ₂ ) may be used.

Here, 0.1 to 2 parts by weight of a platinum (Pt) precursor may be included with respect to 100 parts by weight of the catalyst carrier compound.

The impregnation concentration of the supported platinum precursor is an important variable in the activity of the catalyst, and when the content of the platinum precursor is less than 0.1 parts by weight, the catalytic reaction rate is low due to low catalytic activity, stable catalytic performance cannot be exhibited, and more than 2 parts by weight In this case, there is a problem that the reactivity is rather low compared to expensive precious metals.

Thereafter, the catalyst carrier compound impregnated with the platinum precursor prepared in step (a) is dried and calcined [step (b)].

The drying process is carried out for 3 to 10 hours at a temperature of 80 to 200 ℃ in air or an inert atmosphere in the impregnated material prepared in step (a).

Subsequently, the calcination process of the impregnated material that has undergone the drying process may be performed by heating in air or an inert atmosphere to a temperature of 350 to 900 °C at a temperature increase rate of 1 °C/min or more. Moisture and impurities are removed, and thermal durability and catalytic activity are improved.

Then, the impregnated material dried and calcined in step (b) is mixed with fayalite, and then pulverized in an inert atmosphere using a ball mill [step (c)].

The fayalite (Fe2SiO4) is a silicate containing an iron component, and may be prepared using a silicon precursor and an iron precursor, or a commercially available one may be used without limitation.

As an example of the method for preparing the payelite, it may be obtained by dispersing a silicon precursor and an iron precursor in a solvent such as water or alcohol, and performing a sol-gel reaction such as hydrolysis and/or condensation.

In this case, the solvent is not particularly limited, but water, alcohol, benzene, toluene, xylene, and mixtures thereof may be used, and the amount of the solvent corresponds to 5 to 20 times the weight of the silicon precursor and iron precursor used. It is preferable to use an amount of If the amount is less than 5 times, the dispersion effect is lowered, and if it is 20 times or more, the gelation process may be delayed.

As the silicon precursor, a gaseous, liquid, and solid silicon precursor may be used, and the liquid silicon precursor may be tetraethyl silicate, silicon tetrachloride, organosilane, or the like, and the solid silicon precursor may be silica, silicon carbide, silicon nitride, etc. can

In addition, examples of the iron precursor include iron chlorides such as FeCl2 and FeCl3; iron oxides such as FeO, Fe2O3, and Fe3O4; iron carbides such as Fe5C2 and Fe3C; iron nitrides such as Fe2N, Fe4N, and Fe7N3; iron silicides such as Fe2SiO4 and Fe2O3·SiO2; and iron silicate.

The sol-gel reaction of the reactant in which the silicon precursor and the iron precursor are dissolved may be performed at room temperature to 150° C. for 1 to 15 hours. If the reaction temperature is less than room temperature, the gelation time is long, and if it exceeds 150 °C, gelation may be excessive and the structure may be collapsed.

The reactant thus obtained can be dried and calcined to produce fayalite (Fe2SiO4). After drying for a while, it can be calcined for 1 hour to 5 hours at 500 ° C. to 1,000 ° C. in an inert atmosphere.

If the drying is at 20 ° C. or less than 1 hour, the drying efficiency is not good, if it exceeds 80 ° C. or 24 hours, it may adversely affect the catalyst performance, and if the calcination is 500 ° C. or less than 1 hour, it is difficult to remove the reaction impurities, If it exceeds 5 hours, it may adversely affect catalyst performance, and if it exceeds 1,000° C., it is difficult to atomize, which will be described later, and sintering may occur.

In addition, fayalite (Fe2SiO4) may be obtained by physically mixing an iron precursor such as Fe2O3 or Fe and a silicon precursor such as SiO2, and performing a mechanical synthesis method such as heating it at a high temperature. Thermodynamically, FeO may be stably formed in an Fe-O system at a temperature of 570° C. or higher, which may react with a silicon precursor to form fayerite.

Thereafter, the payelite is mixed with the impregnated material containing the platinum and catalyst carrier dried and calcined in step (b), and then pulverized using a ball mill in an inert atmosphere such as Ar and He to prevent reduction of the reactants. do.

With respect to 100 parts by weight of the catalyst carrier compound, 0.1 to 4 parts by weight of Fayelite may be mixed.

In this case, when the amount of payelite is less than 0.1 parts by weight based on 100 parts by weight of the catalyst carrier compound, the catalyst reaction rate cannot be maximized because the active component of the catalyst is small, and the density of the catalyst is low, so that stable catalytic performance cannot be exhibited. , when it exceeds 4 parts by weight, the particle size of the iron particles, which are the active points of methane activation, increases and the amount thereof increases, which may cause a problem in that the coke generation rate is increased.

In addition, as a preferred embodiment, the amount of the payelite is preferably 150 to 300 parts by weight based on 100 parts by weight of the platinum precursor.

As such, the mixture in which the payelite and the platinum-supported catalyst are mixed is atomized using a ball mill. There is no particular limitation on the ball mill apparatus used for atomizing the mixture in which the payelite and the platinum-supported catalyst are mixed, and a general ball mill apparatus may be used.

As an embodiment, the impregnated material dried and calcined in step (b) is mixed with fayalite, and then pulverized for 4 to 18 hours at a speed of 100 rpm to 300 rpm in an inert atmosphere using a ball mill. can do.

The ball mill is pulverized at a speed of 100 rpm to 300 rpm in an inert atmosphere for 4 to 18 hours in an inert atmosphere to prevent the reduction of paylite and to increase the effect of atomization and uniform mixing. When the proximity of the catalyst supported by fayellite and platinum through the ball mill is increased, there is an effect of increasing the uniformity and density of the catalyst. If the rotation speed and time of the ball mill are less than 100 rpm or less than 4 hours, respectively, there is a limit to controlling the particle size and adjusting the proximity between the particles during atomization of the catalyst on which the payelite and platinum are supported, and it exceeds 300 rpm or 18 hours, respectively. In this case, there may be a problem of lowering the activity of the product due to the sintering of the catalyst carrier and the active metal.

The atomized mixture may have an average diameter of 60 μm or less, preferably 50 nm to 50 μm. If the average diameter of the atomized mixture exceeds 60 μm, there is a limit in controlling the proximity between the particles when the catalyst supported with fayllite and platinum is melted. Problems may arise in controlling the particle size of the particles.

Thereafter, the atomized mixture through a ball mill is put into a reactor, and then melted to obtain a melt [step (d)], and the obtained melt is solidified [step (e)].

At this time, the reactor can be used without limitation as long as it is a material having thermal stability at the melting temperature. It is difficult, and when the height-to-diameter ratio of the reactor exceeds 3, the reduction rate of the active metal of the catalyst increases during melting, and the uniformity and density of the catalyst particles tend to decrease when the melt is solidified through cooling.

The mixture introduced into the reactor may be melted at a temperature at which all of the mixture can be melted, and the melting is performed at 1,200 °C to 2,000 °C in air or an inert atmosphere at 6 °C/min or more, preferably at 6 °C/min to 15 °C It can be carried out by heating at a temperature increase rate of °C/min.

When the melting temperature is less than 1,200 ℃, it is difficult to melt both the catalyst carrier and the catalytically active component, which may cause problems in preparing a uniform catalyst, and when it exceeds 2,000 ℃, the catalyst carrier and the catalytically active component are vaporized A loss may occur, which may cause a problem in preparing a uniform catalyst. At this time, the melting time may be sufficiently melted so as to be sufficiently melted, and preferably may be about 3 to 9 hours.

At this time, the phase change of the catalyst is promoted according to the melting rate, and as a result, a high-density catalyst having high crystallinity can be prepared. There may be problems in promoting the catalyst and lowering the uniformity and density of the catalyst.

Further, after melting, the solidification step may be performed by rapid cooling or natural cooling. The rapid cooling may be performed by gas cooling, water cooling, oil cooling, liquid nitrogen cooling, etc., and preferably rapid cooling may be performed in the range of 0.2 °C/s to 150 °C/s. When the rapid cooling is performed within the above range, the uniformity of the catalyst can be improved by suppressing non-uniformity due to the difference in the melting points of the active metal and the carrier component.

In the gas cooling, the gas may be at least one selected from the group consisting of an inert gas and air, and in the oil cooling cooling, the oil may be mineral oil, rapeseed oil, silicone oil, or the like.

In addition, the catalyst for non-oxidative direct conversion of methane of the present invention can further reduce the pore volume of the catalyst by repeatedly performing the above-described melting step and solidification step. In this case, the number of repetitions of the melting step and the solidification step may be two or more, preferably 2 to 5 times.

The catalyst for non-oxidative direct conversion of methane prepared in this way is uniformly mixed with an inorganic binder, organic binder, water, etc. to obtain a catalyst mixture, which is then molded to prepare a catalyst molded body.

The organic binder may be used in the art, and is not particularly limited, but it is preferable to use at least one selected from methyl cellulose, ethylene glycol, polyol, food oil or organic fatty acid. For a specific example, it is preferable to use hydroxy methyl cellulose or polyvinyl alcohol as the organic binder. In addition, the inorganic binder may be used in the art, and is not particularly limited, but it is preferable to use at least one selected from solid silica, solid alumina, solid silica-alumina, silica sol, alumina sol, and water glass. For a specific example, it is preferable to use fumed silica, silica solution, boehmite, or alumina solution as the inorganic binder.

The catalyst mixture is typically prepared into a catalyst molded body by coating the catalyst mixture on a catalyst structure such as a honeycomb structure or a monolith structure, or by directly extruding the catalyst component of the catalyst mixture. At this time, coating and extrusion molding of the catalyst mixture can be easily prepared by methods used in the art, and detailed descriptions will be omitted.

The catalyst compact may be charged at least one according to the shape of the catalyst compact prepared in the catalyst packing part inside the reactor for non-oxidative direct conversion of methane. The filling method of the catalyst molded body can also be easily filled by a method used in the art.

In another aspect, the present invention is prepared by the above-described production method, includes a catalyst carrier comprising a catalyst carrier compound, and has a high crystalline structure with a specific surface area of 5 m ² /g or less, characterized in that the ratio of methane It relates to a catalyst for direct oxidation conversion. At this time, iron and platinum components, which are heterogeneous active metals, are present on the catalyst carrier in the form of nanoparticles, and include a form in which iron as an active material is dispersed with each other in atomic units on the carrier.

That is, the catalyst for non-oxidative direct conversion of methane may exist in the form of doped iron, which is a catalytically active component, in the lattice of a catalyst carrier compound supported on platinum in a crystalline molten state.

At this time, the average diameter of the platinum or iron particles dispersedly supported on the catalyst carrier may be 5 nm, in this case, the micro stress of the carrier is adjusted to increase the density of the carrier, and defects present in the carrier It is preferable because the number is lowered to allow the methane reaction to proceed smoothly.

As an example, the catalyst for non-oxidative direct conversion of methane may have a structure in which two C atoms and one Si atom are bonded to a single Fe atom and embedded in the silica base when the catalyst carrier compound is made of silica, at this time, The crystal structure of the catalyst carrier is α-crystobalite, and it is characterized in that it is reversibly converted to β-crystobalite when heated to 200 °C ~ 300 °C.

The catalytically active component, platinum (Pt), may be 0.1 to 2.0% by weight based on the total weight of the catalyst, and when the amount of platinum supported is less than 0.1% by weight based on the total weight of the catalyst, the catalytic activity is small, so non-oxidative direct conversion of methane Efficiency may be lowered, and when it exceeds 2.0 wt %, there is a problem in that the reactivity is rather lowered compared to expensive noble metals.

In addition, the catalytically active component of iron may be 0.1 to 2.0 wt% based on the total weight of the catalyst. The non-oxidative direct conversion efficiency of the methane may be lowered, and when it exceeds 2.0 wt%, the amount of iron particles, which are the active points of methane activation, may increase, resulting in a problem in that the coke generation rate is increased.

In addition, as a preferred embodiment, the content ratio of platinum and iron, which is an active component in the catalyst, is preferably 1:1.5 to 1:3.

The catalyst for non-oxidative direct conversion of methane according to the present invention described above prepares an olefin and an aromatic compound by reacting an inert and/or inert gas with methane at a high temperature in the presence of a catalyst.

Specifically, the catalyst according to the present invention is molded, the molded catalyst molded body is placed in the catalyst packing of the reactor, and then methane, an inert gas and/or an inert gas are introduced.

The methane may be 80 to 100% (v/v), more preferably 90 to 100% (v/v), based on the volume of the total gas introduced into the reactor, and an inert gas and/or an inert gas may be 20% (v/v) or less, more preferably 10% (v/v) or less, based on the volume of the total gas.

The inert gas and the inert gas serve to stably generate and maintain a reaction state, and the inert gas may be nitrogen, helium, neon, argon, or krypton, and the inert gas is air, carbon monoxide, hydrogen, carbon dioxide , water, monohydric alcohols (1 to 5 carbon atoms), dihydric alcohols (2 to 5 carbons), alkanes (2 to 8 carbons), and preferably, the inert gas and inert gas may be nitrogen or air.

The reaction temperature may be 900 °C to 1,150 °C, specifically 1,000 °C to 1,100 °C, and the pressure may be 0.1 bar to 10 bar, preferably 0.1 bar to 5 bar. This considers the selectivity and yield of hydrocarbons, and has the advantage of maximizing the selectivity of methane to hydrocarbons. That is, under the above conditions, coke generation is minimized, so that pressure drop due to coke generation during the reaction and carbon efficiency due to coke generation can be minimized.

When the reaction temperature is less than 900 ℃, the radical generation rate due to methane activation is low, so energy efficiency is low. can occur.

As such, the product produced by the direct conversion of methane may be a hydrocarbon including paraffin, olefin, alkyne, such as ethane, ethylene, acetylene, propylene, butylene, benzene, toluene, xylene, ethylbenzene, naphthalene aromatic compound may include

The methane conversion method according to the present invention has the effect of inducing methane activity without precise control of reaction conditions, minimizing coke production, and maintaining a stable yield of hydrocarbon compounds even during long-term operation.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

제조예 1: CRS 촉매Preparation Example 1: CRS catalyst

6 g of quartz, which is a silicon precursor, was put into a reactor, and melted in air to 1700° C. at 8° C./min for 4 hours to obtain a molten catalyst (CRS) having a highly crystalline cristobalite structure.

제조예 2: Fe@CRS 촉매Preparation Example 2: Fe@CRS catalyst

6 g of quartz, a silicon precursor, and 0.056 and 0.112 g of fayalite were ball milled in an Ar atmosphere for 5 hours (ball milling, 250 rpm), and then the ball milled mixture was put into a reactor and , was melted in air to 1700 °C at 8 °C/min for 4 hours to obtain a molten catalyst (0.5Fe@CRS, 1.0Fe@CRS) having an iron loading of 0.5 wt% and 1.0 wt%.

제조예 3-6: Me/Fe@CRS 촉매Preparation 3-6: Me/Fe@CRS catalyst

0.296 g of cobalt nitrate hexahydrate, a cobalt precursor, was dissolved in 50 ml of distilled water, and then 6 g of quartz, a silicon precursor, was dispersed. The mixture was stirred and evaporated at 100 °C for 4 hours, and then dried in an oven at 120 °C overnight. Thereafter, the dried impregnated material was calcined at 400° C. in an air atmosphere to prepare a Co/SiO ₂ catalyst having a loading amount of 0.5 wt%.

6 g of the prepared Co/SiO2 catalyst and 0.112 g of fayalite were ball milled in an Ar atmosphere for 5 hours (ball milling, 250 rpm), and then the ball milled mixture was put into a reactor, and in air. It was melted to 1700 °C at 8 °C/min for 4 hours to obtain a molten catalyst (0.5Co1.0Fe@CRS) having an iron loading of 1.0 wt% and a cobalt loading of 0.5 wt%. A catalyst was prepared in the same manner as described above.

Then, a catalyst was prepared under the conditions shown in Table 1 below, but 0.112 g of fayalite was mixed with 6 g of 0.5 wt% Me/SiO ₂ (Me=Ni, Pd, Pt) and ball milling for 5 hours in an Ar atmosphere. 250 rpm), the ball-milled mixture was put into a reactor and melted in air at 8 °C/min at 8 °C/min for 4 hours to obtain an iron loading of 1.0 wt% and other metal loadings of 0.5 wt%, and a specific surface area A molten catalyst (0.5Me1.0Fe@CRS) of 2 m ² /g or less was obtained.

[Table 1]

[실험예 1] : 메탄 비산화적 직접전환 반응[Experimental Example 1]: Methane non-oxidative direct conversion reaction

Using the catalysts prepared in Examples and Comparative Examples, a non-oxidative direct conversion reaction of methane was carried out at atmospheric pressure and 1020° C. for 10 hours to confirm the conversion rate and selectivity. In the reaction experiment, a quartz material having an inner diameter of 0.4 cm was used as a 1/4 inch fixed-bed reactor. The catalysts prepared in Examples and Comparative Examples were pulverized to have an average particle size of 630 μm, and 0.6 g of the pulverized catalyst was fixed with quartz wool in the center of the reactor. A quartz rod was inserted under the catalyst bed in the reactor to minimize the remaining space. He gas was injected at a flow rate of 40 ml/min while the reactor temperature was raised to 1020 ° C. Then, the reactant containing methane was 990 mlg _cat ^-1 hr ^-1 using a mass flow controller (reactant composition: 90% CH ₄ , 10% Ar) was injected. Ar gas was used as an internal standard.

The gaseous hydrocarbons of the obtained product were analyzed using a GC of Series 6100 of YL Instrument, and the gaseous product was analyzed using a thermal conductivity detector (TCD) connected to a ShinCarbon ST column and a flame ionization detector ( FID) detector was used for analysis. H ₂ , CH ₄ , and CO were separated on a ShinCarbon ST column and detected by TCD, and the conversion rate was calculated as the area of methane compared to the area of Ar, which is an internal standard. Hydrocarbons in the range of C ₁ to C ₁₀ were separated by Rt-alumina BOND column and detected by FID. All gases were quantified using standard samples. The coke selectivity was calculated through [Scoke = 100 - Σ product selectivity]. Table 2 shows the results measured in this way.

[Table 2]

As shown in Table 2, the CRS catalyst and the Fe@CRS catalyst showed relatively low selectivity to aromatic compounds and high coke selectivity compared to the blank experiment. Therefore, it can be seen that, after initial activation of methane, it is advantageous in terms of selectivity to induce the reaction for the C2 product into a gas phase reaction. On the other hand, the 0.5Pt-1,0Fe@CRS catalyst prepared in Example 1 showed a high methane conversion rate, a high yield of aromatic compounds, and low coke selectivity compared to the Fe@CRS catalyst. It was confirmed that the gas phase C2 oligomerization reaction can be induced through the catalyst.

In order to better show the effect of the heterometal catalyst, the coke selectivity for the methane conversion rate in the methane conversion reaction is shown as shown in FIG. 3 below. As a result, in the case of the 0.5Fe@CRS catalyst, it was confirmed that the addition of dissimilar metals did not significantly deviate from the coke selectivity correlation with the methane conversion rate.

However, in the case of the 0.5Pt-1.0Fe@CRS catalyst, it was found that the coke selectivity was shifted to the lower side in the correlation of the coke selectivity to the methane conversion over the Fe@CRS catalyst, and from those close to the Blank-CRS region, the C2 product It was confirmed that coke formation was suppressed through induction of gas phase oligomerization of

[실험예 2] : 메탄 직접 전환 반응 후 촉매에 대한 라만 분석[Experimental Example 2]: Raman analysis of catalyst after methane direct conversion reaction

After the non-oxidative direct conversion reaction of methane, Raman analysis was performed on the catalyst, and the results are shown in Table 3 below.

[Table 3]

As shown in Table 3, the 0.5Pt-1.0Fe@CRS catalyst, which showed a relatively high conversion of methane, showed the lowest I _D1 /I _G peak ratio. This shows that disordered coke originating from aromatic compounds during the reaction was not well produced in the 0.5Pt-1.0Fe@CRS catalyst.

Therefore, it can be confirmed that the catalyst for non-oxidative direct conversion of methane according to the present invention can maximize the catalytic reaction rate and at the same time minimize coke generation and provide a high yield of aromatic compounds in the production of hydrocarbons. there was.

Although the present invention has been described with reference to the above embodiments and the accompanying drawings, other embodiments may be configured within the spirit and scope of the present invention. Accordingly, the scope of the present invention is defined by the appended claims and their equivalents, and not limited by the specific embodiments described herein.

Claims

(a) impregnating the catalyst carrier compound with a platinum (Pt) precursor;

(b) drying and calcining the impregnated material;

(c) mixing the calcined impregnated material with fayalite, followed by pulverization in an inert atmosphere using a ball mill;

(d) introducing the pulverized mixture into a reactor and then melting to obtain a melt; and

(e) a method for preparing a catalyst for non-oxidative direct conversion of methane comprising the step of solidifying the obtained melt.
According to claim 1,

In step (a), 0.1 to 2 parts by weight of a platinum (Pt) precursor is impregnated with respect to 100 parts by weight of the catalyst carrier compound.
The method of claim 1,

The method for producing a catalyst for non-oxidative direct conversion of methane, characterized in that the calcination of step (b) is performed by heating from 300° C. to 900° C. at a temperature increase rate of 1° C./min or more.
The method of claim 1,

In step (c), 0.1 to 4 parts by weight of fayalite is impregnated with respect to 100 parts by weight of the catalyst carrier compound.
According to claim 1,

The step (c) is a method for producing a catalyst for non-oxidative direct conversion of methane, characterized in that the pulverization for 4 hours to 18 hours at a speed of 100 rpm to 300 rpm using a ball mill.
The method of claim 1,

The method for producing a catalyst for non-oxidative direct conversion of methane, characterized in that the melting of step (d) is performed by heating from 1,200 °C to 2,000 °C at a temperature increase rate of 6 °C/min or more.
According to claim 1,

The catalyst carrier compound is a method for producing a catalyst for non-oxidative direct conversion of methane, characterized in that at least one selected from the group consisting of silica, alumina, titania, zirconia and silicon carbide.
It is prepared by the manufacturing method of claims 1 to 7,

A catalyst for non-oxidative direct conversion of methane, comprising a catalyst carrier including the catalyst carrier compound, and having a highly crystalline structure with a specific surface area of 5 m 2 /g or less.
9. The method of claim 8,

The catalyst for non-oxidative direct conversion of methane, characterized in that the supported amount of iron is 0.1 to 2.0 wt% based on the total weight of the catalyst.
9. The method of claim 8,

The catalyst for non-oxidative direct conversion of methane, characterized in that the supported amount of the platinum (Pt) is 0.1 to 2.0 wt% based on the total weight of the catalyst.
9. The method of claim 8,

The catalyst carrier is a catalyst for non-oxidative direct conversion of methane, characterized in that it is in a molten crystalline state.