KR101970811B1 - Co based catalyst for Fischer-Tropsh process supported in mesoporous zeolite and Preparation method for synthetic liquid fuel using the same - Google Patents

Abstract

The present invention relates to a cobalt supported catalyst for a Fischer-Tropsch process, which forms a synthetic liquid fuel from a syngas, wherein first particles of zeolite crystals gather to form mesoporous second particles having a mesopore size distribution of 5-40 nm Wherein the zeolite support has a specific surface area of 200 to 600 m by controlling the crystallization temperature during the hydrothermal synthesis of the zeolite support, wherein the zeolite support has a mesopore of 15 to 25% by weight, based on the total weight of the zeolite, ² / g, and meso pore volume (V _meso ) of from 0.05 to 0.3 cm ³ / g is used as a support for a cobalt supported catalyst for a Fischer-Tropsch process.
According to the present invention, a cobalt catalyst using mesoporous zeolite as a support can easily form highly dispersed cobalt nanoparticles by mesopores, thereby achieving a higher syngas conversion rate, and the generated hydrocarbons can be rapidly moved in mesopores Thereby accelerating the cracking and isomerization reaction. Therefore, a liquid fuel having high fluidity can be obtained at a high yield even without an additional upgrading step.

Description

TECHNICAL FIELD The present invention relates to a cobalt catalyst for a Fischer-Tropsch process supported on a mesoporous zeolite, and a method for producing a synthetic liquid fuel using the same.

The present invention relates to a cobalt catalyst for the Fischer-Tropsch process supported on a mesoporous zeolite and to a process for producing a synthetic liquid fuel using the same.

In general, nanoporous materials are classified into microporous (less than 2 nm), mesoporous (2 to 50 nm), and macroporous (more than 50 nm) depending on their pore size. The mesoporous material has a relatively large surface area and a pore size suitable for supporting the active material, so that the mesoporous material is highly applicable to various fields as compared with other porous materials.

Generally, mesoporous materials are synthesized by using organic molecules such as surfactant or amphiphilic block copolymer as structural derivatives forming a porous structure. The common point of the organic molecules used as the structural derivatives is that they include both hydrophilic and hydrophobic moieties so that it is possible to self-assemble into various nanostructures according to the volume fraction (concentration) of each moiety. Using this concept, it is possible to control the amount of hydrophilic / hydrophobic precursors that are simply put into the self-assembly process using a single amphiphilic block copolymer to form lamellar, hexagonal, cubic, and a spherical mesoporous structure can be easily synthesized.

Most of the syngas produced by reforming natural gas, shale gas, coal, and other resources with steam is carbon monoxide and hydrogen. These syngas can be converted to various forms of energy and chemicals, including synthetic crude oil, through the Fischer-Tropsch synthesis process.

The catalysts used in the Fischer-Tropsch process can be roughly divided into iron (Fe) -based catalysts and cobalt (Co) -based catalysts. Both series catalysts are prepared by adding alkali metals such as Na and K and a small amount of noble metals such as Pt and Pd to control the conversion of carbon monoxide and selectivity of products.

Iron-based catalysts are used in Fischer-Tropsch synthesis reactions at relatively high temperatures (300 to 450 ° C) and their products are not only raw materials for the chemical industry such as light olefins and alpha-olefins, but also liquid fuels in the gasoline range, and alcohols, aldehydes, And oxygen-containing compounds. The Fischer-Tropsch synthesis process using the iron-based catalyst has the advantage that various products can be obtained at one time, but the disadvantage of obtaining a desired compound through a subsequent separation process is also accompanied.

When cobalt-based catalysts are used in a high-temperature Fischer-Tropsch synthesis process, they are used at relatively low temperatures (220 to 300 ° C) because of high methane production rates. The product of the cobalt-based catalyst is mainly composed of linear paraffins having 8 to 25 carbon atoms and has high selectivity for such hydrocarbon products. However, since the linear paraffin is present in the wax state at room temperature, It should be converted to gasoline, diesel domain hydrocarbons through grading process.

The upgrading process may include cracking or isomerization of linear paraffins using amorphous silica-alumina or crystalline zeolites with strong acid sites to shorten the number of carbon atoms or make olefins and isoparaffins to produce fluidity at room temperature It is a process to make liquid fuel. Since this subsequent upgrading process requires additional cost, various methods have been tried to omit this and to produce liquid fuel at once in the Fischer-Tropsch process.

US Patent No. 5,104,902 discloses a process for producing liquid hydrocarbons by synthesizing ZSM-5 zeolites having different crystal sizes and using them as a support to prepare a cobalt catalyst. US Patent Nos. 4,652,538 and 7,943,674 ZSM-5 zeolite exhibits a high methane selectivity and a low C10 or higher hydrocarbon selectivity, a process for producing liquid hydrocarbons using a cobalt catalyst using zeolite Y and ZSM-12 as a support has been proposed. However, since the zeolite supports used in the above patents have a small pore size and a small surface area, it is difficult to effectively carry large amounts of cobalt nanoparticles, so that the conversion of CO to the amount of catalyst is lower than that of conventional Al ₂ O ₃ or SiO ₂ , .

As a typical method of providing zeolite with mesopores, there is a post-treatment method in which silicon of a zeolite support is selectively dissolved by using an alkali solution as in the case of US Pat. No. 9,120,090. However, this method is disadvantageous in that the disappearance of the zeolite support itself is as low as 10 wt%, and as much as 80 wt%, which is not economical.

The present invention synthesizes zeolite having a mesopore without loss of zeolite itself and improves the activity of the Fischer-Tropsch reaction by using it as a support of a cobalt catalyst and accelerates the isomerization reaction and the cracking reaction, To provide a cobalt-based catalyst capable of producing a syngasic liquid fuel.

In a first aspect of the present invention, there is provided a cobalt supported catalyst for a Fischer-Tropsch process for forming a synthetic liquid fuel from a syngas, wherein a first particle consisting of zeolite crystals is gathered to form a meso-zeolite having a mesopore size distribution of 5-40 nm The catalyst active component containing cobalt in an amount of 15 to 25% by weight based on the total weight of the zeolite is supported on the mesopores of the zeolite support on which the porous second particles are formed. By controlling the crystallization temperature during the hydrothermal synthesis of the zeolite support, _Supported on a zeolite supported on a support of zeolite controlled to have a volume of 200 to 600 m ² / g and a mesopore volume (V _meso ) of 0.05 to 0.3 cm ³ / g.

A second aspect of the present invention provides a method for producing a synthetic liquid fuel from a syngas, with a cobalt supported catalyst for a Fischer-Tropsch process activated in accordance with the first aspect of the present invention.

Hereinafter, the present invention will be described in detail.

As long as it contains carbon monoxide and hydrogen as catalyst reactants, it belongs to the synthesis gas category of the present invention.

The synthetic liquid fuel as the catalyst product comprises hydrocarbons formed from Fischer-Tropsch reaction from synthesis gas, preferably gasoline and / or diesel grade hydrocarbons.

The present invention relates to a cobalt supported catalyst for a Fischer-Tropsch process for forming a synthetic liquid fuel from a syngas, in which, in order to support a cobalt-containing catalytically active component in mesopores of a zeolite, first particles of zeolite crystals are collected, And having a specific surface area of 200 to 600 m ² / g and a mesopore volume (V _meso ) of 0.05 to 0.3 cm ³ / g, wherein the mesoporous second particles have a distribution of 5 to 40 nm, It is characteristic to use.

The average particle diameter of the first particles made of zeolite crystals is preferably 20 to 40 nm so that the mesopore size distribution of the second particles is 5 to 40 nm.

By controlling the crystallization temperature during the hydrothermal synthesis of the zeolite support, the zeolite crystals aggregate and the pores formed between the first particles are adjusted to a mesopore size of 5 to 40 nm, preferably 10 to 40 nm And the specific surface area is 200 to 600 m ² / g, and the mesopore volume (V _meso ) is adjusted to 0.05 to 0.3 cm ³ / g (Table 1, Experimental Example 1).

Therefore, the cobalt-supported catalyst for the Fischer-Tropsch process according to the present invention has mesopores and enhances the activity of the catalyst by using a zeolite having distributed strong acid sites as a support of a cobalt-based catalyst, and at the same time, Olefin to the Fischer-Tropsch reaction to produce a highly fluid synthetic liquid fuel without a separate up-grading process.

As the mesopore size of the mesoporous zeolite support increases, the dispersity and activity of the Co catalyst may be proportionally increased. However, when the mesoporous zeolite support has a mesopore size of less than 5 nm, long-chain hydrocarbons produced in the cobalt active phase can not migrate rapidly within the zeolite, thus restricting cracking reaction and isomerization. At the same time, Causing a low turnover frequency per active point. If the mesopore size is more than 40 nm, the stability of the zeolite structure is lowered.

When the specific surface area of the mesoporous zeolite support is less than 200 m ² / g or the meso pore volume (V _meso ) is less than 0.05 cm ³ / g, the catalyst active phase is not dispersed smoothly after cobalt loading, There is a problem in that the conversion rate of the synthesis gas per unit weight of the mesopores is low. When the specific surface area exceeds 600 m ² / g or the meso pore volume (V _meso ) exceeds 0.3 cm ³ / g, The carbon chain bonding reaction is limited and it is difficult to achieve a sufficient hydrocarbon size for liquid fuel production and the density of the entire catalyst is low, which makes it difficult to design a catalyst fixed bed reactor.

There is no particular limitation on the kind of the zeolite crystal that is the basic structure of the mesoporous zeolite, but preferably MFI, MTW or FAU can be used.

The zeolite of the above structure is suitable for cracking and isomerization of hydrocarbons produced by Fischer-Tropsch synthesis because the acid sites are relatively stable and uniformly distributed.

A support suitable for use in cobalt-supported catalysts for the Fischer-Tropsch process for the production of synthetic liquid fuels from syngas according to the present invention is characterized in that first particles of zeolite crystals are gathered to form a meso-zeolite having a mesopore size distribution of 5-40 nm A zeolite support having a specific surface area of 200 to 600 m ² / g and a mesopore volume (V _meso ) of 0.05 to 0.3 cm ³ / g, having porous second particles formed thereon, Can be provided:

(a) preparing a synthetic gel containing a silicon precursor, an aluminum precursor, an organic mold compound, and water;

(b) controlling the crystallization temperature during hydrothermal synthesis to form first mesoporous particles by aggregating first particles of zeolite crystals; And

(c) firing the hydrothermal synthesis product of step (b) to remove the organic template compound.

The method of preparing mesoporous zeolite by controlling the crystallization temperature according to the present invention is economical because it can form zeolite without loss of zeolite itself as compared with the method of forming mesopores using alkali solution.

Step (a) is a step of dissolving the silicon precursor, the aluminum precursor, and the organic template compound, which determine the structure of the zeolite, in water in a proper ratio to prepare a gel-like solution without precipitate. The synthetic gel of step (a) may be an aqueous alkali solution in which a small amount of sodium hydroxide (NaOH) is dissolved to adjust the acidity.

The silicon precursor is not particularly limited but may be a gel or an aqueous solution containing SiO ₂ (silica gel or water glass (SiO ₂ + Na ₂ O), tetramethyl orthosilicate (TMOS, Si (OCH ₃ ) ₄ ) ethyl ortho silicate (tetraethyl orthosilicate: TEOS, Si ( OC 2 H 5) 4), tetrapropyl orthosilicate (tetrapropyl orthosilicate: TPOS, Si ( OC 3 H 7) 4), sodium silicate (sodium silicate: Na ₂ SiO ₃ ) may be used.

The aluminum precursor is not particularly limited but may be selected from the group consisting of sodium aluminate (NaAlO ₂ ), aluminum nitrate (Al (NO ₃ ) ₃ ), aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) propoxide (aluminum isopropoxide: Al (O ( CH (CH 3) 2))) and the like can be used. The aluminum precursor may preferably be an aluminum precursor containing an alkali metal so that the acid point can be formed in the zeolite support through ion exchange, and more preferably an aluminum precursor containing Na can be used.

The organic template compound may include ammonium or amine. Specifically, the organic mold compound may be tetramethylammonium (TMA, (CH ₃ ) ₄ N), tetraethylammonium (TEA, _{C 2 H 5) 4 N)} , tetrapropylammonium (tetrapropylammonium: the ammonium cations such as _{TBA, (C 4 H 9)} 4 N)): TPAOH, (C 3 H 7) 4 N), tetrabutylammonium (tetrabutylammonium An ammonium salt bonded with an anion such as hydroxide (OH), bromine (Br), chlorine (Cl) or the like; n- butylamine (n-butylamin: BTA, CH 3 (CH 2) 3 NH 2), amine _{(ethylamine: ETA, CH 3 CH} 2 NH 2), isopropylamine _{(isopropylamine: IPA, (CH 3} ) 2 CHNH ₂ ), or an amine such as ethylenediamine (EDA, NH ₂ CH ₂ CH ₂ NH ₂ ) may be used.

 In the step (a), the order of mixing the silicon precursor, the aluminum precursor, and the organic template compound into water is not limited. Preferably, the silicon precursor and the organic template compound are first dissolved in water to prepare an aqueous solution. Or a solution containing an aluminum precursor dissolved in an aqueous alkali solution may be added to a solution containing a silicon precursor and an organic template compound to obtain a gel-free solution without precipitation, and this gel-like solution may be aged for 1 to 7 days, Preferably 3 hours to 24 hours, at room temperature.

In the step (a), the mixing ratio of the silicon precursor, the aluminum precursor, the organic template compound and the alkali metal is not limited, but preferably the molar ratio of silicon / aluminum compound is 5 to 50, the molar ratio of silicon / organic compound is 0.1 to 1, Aluminum molar ratio of 0 to 5. < / RTI >

(b) is a step of hydrothermally synthesizing the synthetic gel of step (a) by introducing it into a high-pressure isothermal reactor. The degree of crystallization of the zeolite can be controlled according to the temperature, pressure and reaction time of the hydrothermal synthesis, and the degree of formation of the mesopores in the second particles formed by gathering the first particles made of zeolite crystals can be controlled.

In order to adjust the mesopore size distribution of the zeolite to 5 to 40 nm, the temperature of the hydrothermal synthesis may be adjusted to 100 to 300 ° C, preferably 110 to 200 ° C.

The pressure in the reactor during the hydrothermal synthesis is determined depending on the type and amount of the synthetic gel to be added, but may preferably be 0.5 to 10 MPa.

The reaction time for the hydrothermal synthesis may be from 6 hours to 20 days, preferably from 6 to 72 hours, but is not limited thereto.

As the reaction pressure and temperature increase in hydrothermal synthesis and the reaction time increases, the volume of mesopore per zeolite unit mass decreases.

(c) is a step of washing and firing the hydrothermal synthesis product of step (b), preferably by removing the organic template compound.

For example, washing is performed by centrifugation or filtration using tertiary distilled water, and the solid remaining after 3 to 10 times of washing is dried at 80 to 120 ° C for 3 to 24 hours under reduced pressure to normal pressure, To remove any remaining water and organic template compounds.

When an alkali metal-containing aluminum precursor is used as an aluminum precursor in the synthesis gel of step (a), an alkali metal-zeolite (for example, Na-zeolite) can be obtained in the step (c).

In this case, in order to produce the zeolite support according to the present invention, the step (d) of converting alkali metal into alkali metal-zeolite obtained in the step (c) into proton ions and firing to convert them into H- .

For example, Na bonded to an aluminum site in the zeolite structure obtained in the step (c) is ion-exchanged with NH ₄ in an aqueous solution containing ammonium nitrate (NH ₄ NO ₃ ) dissolved therein to form an NH ₄ bond in the aluminum site in the mesoporous zeolite structure Zeolite can be produced by calcining it to form H-zeolite. At this time, the concentration of ammonium nitrate is not limited, but it may be preferably 0.5 to 2 molar.

The duration of the ion exchange reaction in the step (d) is not particularly limited, but may be 1 to 12 hours. The temperature of the ion exchange reaction is not limited, but may be preferably 60 to 90 ° C. There is no limitation on the number of times, but it is preferably 1 to 3 times.

The firing temperature in step (d) may be 500 to 700 ° C.

According to the present invention, when the catalyst active component containing cobalt is supported on the mesopores of the zeolite support, the amount of supported catalyst is preferably 15 to 25% by weight based on the total weight of the zeolite. When the amount is less than 15% by weight, it is difficult to obtain a sufficient yield of hydrocarbons in the Fischer-Tropsch reaction. When the amount is more than 25% by weight There is a problem that the cobalt particles are sintered to each other and the particle size becomes excessively large and the active surface area is reduced.

There is no particular limitation on the method for supporting cobalt in the mesopores of the zeolite support, but preferably impregnation or initial impregnation may be used. There is no particular limitation on the cobalt precursor used for impregnation or initial impregnation, and preferably cobalt nitrate hydrate salt or cobalt acetate can be used.

The mesoporous zeolite carrying the cobalt precursor may be calcined at 400 to 600 ° C to obtain a cobalt oxide / zeolite powder.

The cobalt supported catalyst for the Fischer-Tropsch process of the present invention is a catalyst for supporting one or a mixture of metals selected from the group consisting of Pt, Pd, Rh, Ru and Ir to enhance the Fischer-Tropsch activity of the catalyst . At this time, the amount of the secondary metal to be supported together is preferably 0.01 to 0.1% by weight.

The present invention also provides a method for producing a synthetic liquid fuel from a syngas, with the cobalt supported catalyst for the Fischer-Tropsch process of the present invention being activated.

The synthetic liquid fuel production method

A first step of applying a cobalt supported catalyst for a Fischer-Tropsch process to a reactor;

A second step of activating a cobalt supported catalyst for the Fischer-Tropsch process; And

A third step of producing a synthetic liquid fuel from the synthesis gas in the presence of the catalyst

. ≪ / RTI >

The use of the catalyst according to the invention makes it possible to obtain a liquid hydrocarbon product with substantially no or substantially reduced, i.e. a high yield, of solid wax from the synthesis gas.

The method for producing a synthetic liquid fuel according to the present invention can prepare a synthesis gas (CO / H ₂ ) by reforming the natural gas at least before the third step.

On the other hand, the Fischer-Tropsch process reactor may be a fixed bed, fluidized bed or slurry reactor. Preferably, a continuous reactor as shown in Fig. 1 can be used.

The second step is to activate the cobalt supported catalyst for the Fischer-Tropsch process in the reactor. For example, hydrogen may be added at 300 to 600 ° C to reduce the cobalt-containing catalyst component. At this time, the activation time may be 2 to 12 hours.

If the catalyst activation temperature is lower than 300 ° C, the catalytic activity phase in the cobalt oxide state may not be properly reduced and may not be activated. If the catalyst activation temperature is higher than 600 ° C, the active surface area due to sintering of the cobalt particles may decrease.

The third step is the step of injecting a synthesis gas containing carbon monoxide and hydrogen in the presence of the activated catalyst to produce a synthetic liquid fuel, preferably without a solid wax component.

The third step can be carried out at a reaction temperature of 200 to 270 ° C, preferably at a reaction temperature of 230 to 250 ° C. Fischer-Tropsch reaction may not occur when the reaction proceeds at a temperature lower than 200 ° C., and when the reaction proceeds at a temperature higher than 270 ° C., the methanation reaction of Co occurs excessively and the selectivity of the liquid fuel is decreased. May occur.

The third step is preferably carried out under the conditions of 1 to 3 MPa of reaction pressure, 2000 to 6000 ml / g _cat h and H ₂ / CO ratio of 1.5 to 2.5.

1, according to one embodiment of the present invention, a continuous reactor 10 equipped with an activated cobalt-supported mesopore zeolite catalyst is provided with a hydrogen storage vessel 91 and a carbon monoxide storage vessel 90, And carbon monoxide are mixed in a mixer, and then the Fischer-Tropsch reaction proceeds. In addition, the product produced by the Fischer-Tropsch reaction is separated and recovered from the continuous reactor, and the produced product is separated into a gaseous C ₁ -C ₄ hydrocarbon and a liquid C ₅ or higher hydrocarbon, Liquid separator 50 and discharged through the decompression device 70 located at the discharge port.

According to the present invention, a cobalt catalyst using mesoporous zeolite as a support can easily form highly dispersed cobalt nanoparticles by mesopores, thereby achieving a higher syngas conversion rate, and the generated hydrocarbons can be rapidly moved in mesopores Thereby accelerating the cracking and isomerization reaction. Therefore, a liquid fuel having high fluidity can be obtained at a high yield even without an additional upgrading step.

In addition, the mesoporous zeolite support of the present invention is economical because zeolite can be produced without loss of zeolite itself as compared with mesoporous formation using a conventional alkaline solution.

1 is a schematic diagram of a synthetic liquid fuel production system according to an embodiment of the present invention.
2 is a pore size distribution diagram of a zeolite carrier analyzed by N ₂ isothermal adsorption / desorption.
3 is a scanning electron microscope image of the zeolite carrier prepared in Examples 1 to 6 of the present invention.
4 is (a) N ₂ adsorption isotherm and (b) pore size distribution diagram according to Experimental Example 3.
Fig. 5 is an X-ray diffraction analysis pattern according to Experimental Example 4. Fig.
6 is a CO conversion rate according to the reaction time of Experimental Example 5. Fig.
7 is a product distribution chart and a product photograph according to the carbon number in Experimental Example 5.

Hereinafter, embodiments of the present invention will be exemplified. The following examples are provided to illustrate the present invention in order to facilitate understanding of the present invention, and thus the technical scope of the present invention is not limited thereto.

< Example  1> At 120 ° C  Hydrothermally synthesized zeolite Carrier  Produce

(TEOS), sodium aluminate (NaAlO ₂ ), and tetrapropylammonium hydroxide (TPAOH), respectively, as a silicon precursor, an aluminum precursor, and an organic template compound in order to synthesize a mesoporous zeolite having mesopores Respectively. First, NaAlO ₂ was added to an aqueous solution at 60 ° C in which TEOS and TPAOH were dissolved and stirred for 3 hours to form a gel. At this time, the molar ratio of TEOS: NaAlO ₂ : TPAOH: water was 25: 1: 10: 1100 and the pH of the aqueous solution was 11.5. For crystallization through hydrothermal synthesis, the gel was placed in a high-pressure reactor and heated at 120 ° C. for 24 hours. The white solid obtained after the reaction was washed 5 times with distilled water, dried at 110 ° C for 24 hours, and then calcined at 600 ° C for 6 hours to remove remaining organic substances and precursors. The Na-MFI zeolite obtained after calcination was converted to NH ₄ -MFI zeolite by ion-exchange for 5 hours using a 1 M ammonium nitrate aqueous solution. That was obtained following the NH ₄ -MFI zeolite for 6 hours at 600 H-MFI zeolite by calcination for.

< Example  2> At 130 ° C  Hydrothermally synthesized zeolite Carrier  Produce

Zeolite was prepared in the same manner as in Example 1, except that the temperature of the crystallization step through hydrothermal synthesis was set at 130 ° C instead of 120 ° C to proceed the reaction.

< Example  3> At 140 ° C  Hydrothermally synthesized zeolite Carrier  Produce

Zeolite was prepared in the same manner as in Example 1, except that the temperature of the crystallization step through hydrothermal synthesis was set at 140 ° C instead of 120 ° C to proceed the reaction.

< Example  4> At 160 ° C  Hydrothermally synthesized zeolite Carrier  Produce

Zeolite was prepared in the same manner as in Example 1, except that the temperature of the crystallization step through hydrothermal synthesis was set at 160 ° C instead of 120 ° C to proceed the reaction.

< Example  5> At 200 ° C  Hydrothermally synthesized zeolite Carrier  Produce

A zeolite was prepared in the same manner as in Example 1, except that the temperature of the crystallization step through hydrothermal synthesis was set at 200 ° C instead of 120 ° C to proceed the reaction.

< Example  6> At 230 ℃  Hydrothermally synthesized zeolite Carrier  Produce

Zeolite was prepared in the same manner as in Example 1, except that the temperature of the crystallization step through hydrothermal synthesis was set at 230 ° C instead of 120 ° C to proceed the reaction.

< Example  7> At 120 ° C  The hydrothermally synthesized zeolite Supported  Preparation of cobalt catalyst

The MFI zeolite prepared in Example 1 was impregnated with 20 wt% of cobalt by impregnation.

Specifically, 2 g of the MFI zeolite prepared in Example 1 was impregnated with 20 ml of an aqueous solution of Co (NO ₃ ) ₂ 6H ₂ O, followed by vacuum evaporation drying at 70 ° C for about 4 hours. The recovered powder was dried at 100 ° C. for 24 hours and then calcined at 550 ° C. for 6 hours to prepare a cobalt catalyst supported on MFI zeolite. This catalyst is represented by Co / m-MFI.

< Example  8> At 230 ℃  The hydrothermally synthesized zeolite Supported  Preparation of cobalt catalyst

Using the MFI zeolite prepared in Example 6, a cobalt catalyst supported on MFI zeolite was prepared in the same manner as in Example 7.

< Example  9> At 120 ° C  The hydrothermally synthesized zeolite Supported  Preparation of synthetic liquid fuel using cobalt catalyst

0.4 g of a cobalt catalyst (Co / m-MFI, 20 wt% Co) supported on the mesoporous zeolite of Example 7 was introduced into a continuous-type reactor having a volume of about 16 ml as shown in Fig. 1, to 5% H ₂ / Ar at a flow rate of 80 ml / min was flowed activate the catalyst for 7 hours. After the completion of the catalyst activation, the temperature was lowered to 240 ° C., and a synthesis gas having a ratio of H ₂ / CO of 2 was introduced into the continuous reactor at a rate of 26 ml / min under 2.0 MPa and reacted to prepare a synthetic liquid fuel. At this time, the reaction was continued for 60 hours.

< Example  10> At 230 ℃  The hydrothermally synthesized zeolite Supported  Preparation of synthetic liquid fuel using cobalt catalyst

A synthetic liquid fuel was prepared in the same manner as in Example 9 except that the Co / MFI catalyst of Example 8 was used instead of the Co / m-MFI catalyst of Example 7.

< Comparative Example  1 > Co / Al ₂ O ₃  Preparation of synthetic liquid fuel using catalyst

Except that the Co / Al ₂ O ₃ catalyst (Co 20% by weight) was used instead of the Co / m-MFI catalyst of Example 7 and the activation temperature was set at 550 ° C instead of 400 ° C. To produce a synthetic liquid fuel.

< Experimental Example  1> Meso  Analysis of surface area and pore size of zeolite

, N ₂ isothermal adsorption-desorption experiments using a Micrometrics Inc. ASAP-2420 total surface area (S _BET) to investigate the Examples 1-6 Structural characteristics, including pore size of the resulting zeolite carrier in accordance with according to the invention, The external surface area (S _ext ), the total pore volume (V _total ), the micropore volume (V _micro ), and the mesopore volume (V _meso ) were measured and the results are shown in Table 1 and FIG.

The surface area and pore volume of the zeolite carrier analyzed by N ₂ isothermal adsorption / desorption sample S _BET (m ² / g) S _ext
(m ² / g) V _total (cm ³ / g) V _micro (cm &lt; ³ &gt; / g) V _meso (cm ³ / g) V _meso / V _total Example 1 (120 &lt; 0 &gt; C) 441.0 122.2 0.398 0.127 0.213 0.54 Example 2 (130 &lt; 0 &gt; C) 440.1 70.3 0.393 0.150 0.180 0.46 Example 3 (140 &lt; 0 &gt; C) 404.8 41.9 0.252 0.142 0.073 0.29 Example 4 (160 &lt; 0 &gt; C) 407.7 36.1 0.258 0.139 0.072 0.28 Example 5 (200 &lt; 0 &gt; C) 417.5 28.3 0.209 0.157 0.035 0.17 Example 6 (230 &lt; 0 &gt; C) 401.8 27.4 0.197 0.150 0.035 0.18

As shown in Table 1, the zeolite supports of Examples 1 and 2 exhibited substantially the same BET specific surface area regardless of the crystallization temperature. However, as the crystallization temperature decreases, the surface area, total pore volume, and mesopore volume increase. Particularly, with the result that the size of the micro pore does not change and only the value of the mesopore increases, the increase of the mesopore distribution with decreasing temperature in the pore pore distribution shown in FIG. 2 has a direct effect on the formation of the mesopore I do not know.

< Experimental Example  2> Meso  Observing crystal form of zeolite

The zeolite prepared according to Examples 1 to 6 according to the present invention was a crystal of ZSM-5 structure. The crystal form of the zeolite carrier was observed with a scanning electron microscope, and the results are shown in FIG.

As shown in FIG. 3, in the case of a sample crystallized at a low temperature, small crystals having a size of 20 to 40 nm are gathered to form one large crystal. As the crystallization temperature increased, the degree of aggregation of the small crystals increased and the roughness of the surface tended to decrease significantly. When the crystallization temperature reached 200 ° C, roughness of the surface of the zeolite disappeared and many clear crystals were observed. A smooth and clean surface was observed in all the crystals without any small crystals or rough surfaces.

< Experimental Example  3> Cobalt Of the supported catalyst  Surface area and pore size analysis

The surface area and pore size of the cobalt-supported catalyst of Example 7, Example 8 and Comparative Example 1 according to the present invention were measured by N ₂ isothermal adsorption / desorption experiments. N ₂ isothermal adsorption / desorption experiments were carried out using ASAP-2420 from Micrometrics.

As shown in Fig. 4 (a), the zeolite-supported cobalt-supported catalyst of Example 7 shows an adsorption / desorption isotherm with mesopores and the zeolite-supported cobalt catalyst of Example 8 shows an adsorption / desorption isotherm without mesopores. The cobalt catalyst supported on Al ₂ O ₃ of Comparative Example 1 also exhibits a mesoporous adsorption / desorption isotherm. 4 (b), the mesoporous zeolite supported on the mesoporous zeolite prepared in Example 7 showed a mode of pore size of 20 nm at the most, and the zeolite having no mesopores prepared in Example 8 It was found that the supported cobalt catalyst had no pores having a size of 10 nm or more. The cobalt catalyst supported on Al ₂ O ₃ prepared in Comparative Example 1 had a very large number of pores at about 10 to 50 nm.

< Experimental Example  4> Cobalt Of the supported catalyst  X- Ray diffraction  analysis

In order to compare the cobalt particle sizes of Example 7, Example 8, and Comparative Example 1 according to the present invention, X-ray diffraction was analyzed and the results are shown in FIG. X-ray diffraction was measured using D / Max-RC of Rigaku.

As shown in FIG. 5, it can be seen that the zeolite prepared in Example 7 and Example 8 formed MFI structure well regardless of the pore size. The size of the cobalt nanoparticles was larger in the order of Al ₂ O ₃ support (Comparative Example 1) having mesopores, mesoporous zeolite support (Example 7), and mesoporous zeolite support (Example 8) And that the presence of mesopores allows easy dispersion of the cobalt nanoparticles.

< Experimental Example  5> Determination of CO conversion and quantification of synthetic liquid hydrocarbons

The conversion rates of CO reacted in Examples 9 and 10 and Comparative Example 1 according to the present invention were defined from the concentration of CO participating in the reaction and the concentration of CO in the recovered air stream, That is, the selectivity for hydrocarbons was defined by the following formula from the weight of each component separated from the recovered hydrocarbons. For the determination of CO and gaseous hydrocarbons, gas chromatography produced by Younglin was used. A thermal conductivity detector connected with Porapak Q and a molecular sieve (5A) and a flame ionized detector connected with GS-GASPRO Respectively. The quantification of liquid hydrocarbons was carried out using gas chromatography equipped with a flame ionization detector connected to Younglin's HP-1.

As shown in FIG. 6, Example 9 and Comparative Example 1 showed a high CO conversion of greater than 70% over a reaction time of 60 hours after a stabilization time of 20 hours, whereas Example 10 exhibited a CO conversion of about 40% CO conversion. From this, it was confirmed that the formation of the mesopores of the support and the resulting high dispersion cobalt nanoparticles were advantageous for the Fischer-Tropsch reaction activity.

Table 2 below shows CO conversion, hydrocarbon selectivity, isoparaffin and olefin production rates at 40 hours after the start of the reaction.

sample CO conversion (%) Selectivity (%) (Isoparaffin + olefin) / total hydrocarbons C1 C2-C4 C5-C11 C12-C20 C21 + Example 9 73.6 13.5 13.6 51.38 20.66 0.84 0.618 Example 10 40.4 16.4 15.9 38.46 28.49 0.74 0.679 Comparative Example 1 72.0 13.6 15.0 38.67 28.43 4.29 0.204

In Examples 9 and 10 using zeolite as a support, it was confirmed that the chain length of the liquid hydrocarbon was shorter than that of Comparative Example 1 due to the cracking reaction and the promotion of the isomerization reaction, and the production rate of isoparaffin and olefin was increased.

FIG. 7 shows the distribution of the products according to the number of carbon atoms and the photographs of the obtained products. The product of Example 9 and Example 10 using a zeolite support catalyst was a liquid having a fluidity at room temperature, but the product of Comparative Example 1 using an Al ₂ O ₃ support catalyst was a waxy product in a solid state at room temperature. It was confirmed that in Example 10, relatively low liquid product was produced due to low CO conversion.

As a result, the cobalt catalyst supported on the mesoporous zeolite support according to the present invention has high dispersion degree of cobalt particles due to the mesopores, so that the reaction product can be effectively reacted to obtain a product with a high yield, It can be seen that the cracking and isomerization reaction of the produced hydrocarbons is promoted to obtain liquid hydrocarbons having fluidity at room temperature.

10: reactor; 20 heating furnace; 30 preheater; Mass flow controller; 50: trap and gas-liquid separator; 60: pressure gauge; 70: Back pressure regulator; 80, 81: Gas chromatography; 90, 91: Reactant cylinder; 100: Syringe

Claims (14)

A method for producing a cobalt supported catalyst for a Fischer-Tropsch process, which forms a synthetic liquid fuel from a syngas,
(a) preparing a synthetic gel containing a silicon precursor, an aluminum precursor, an organic mold compound, and water;
(b) adjusting the crystallization temperature to 100 ° C to 130 ° C during hydrothermal synthesis so that the first particles of zeolite crystals gather to form mesoporous second particles; And
(c) removing the organic template compound by calcining the resultant product obtained by the hydrothermal synthesis in the step (b)
And a zeolite support preparation step,
The catalyst comprises 15 to 25% by weight of zeolite based on the total weight of the zeolite in the mesopores of the zeolite support in which the first particles of zeolite crystals are gathered to form mesoporous second particles having a mesoporous size distribution of 5 to 40 nm Cobalt-containing catalyst active component,
The zeolite support has a specific surface area of 200 to 600 m ² / g and a mesopore volume (V _meso ) of 0.05 to 0.3 cm ³ / g by controlling the crystallization temperature during hydrothermal synthesis of the zeolite support A method for preparing a cobalt supported catalyst for Fischer-Tropsch process. The process of claim 1, wherein the catalyst is selected from the group consisting of: performing a Fischer-Tropsch synthesis reaction by an activated cobalt-containing catalyst component; performing cracking, isomerization or both of the products of the Fischer- &Lt; / RTI &gt; wherein the cobalt supported catalyst is supported on a support. The method for producing a cobalt supported catalyst for a Fischer-Tropsch process according to claim 1, wherein the average particle diameter of the first particles made of zeolite crystals is 20 to 40 nm. The method of claim 1, wherein the catalyst is one or a mixture of metals selected from the group consisting of Pt, Pd, Rh, Ru and Ir. The process for producing a cobalt supported catalyst for a Fischer-Tropsch process according to claim 1, wherein an alkali metal-containing aluminum precursor is used as an aluminum precursor, and alkali metal-zeolite is obtained in the step (c). 6. The method of claim 5, further comprising the step of: (d) converting alkali metal to alkali metal-zeolite obtained in step (c) and converting the alkali metal to protons to convert them to H- A method for producing a cobalt supported catalyst for a tropic process. The method according to claim 1, wherein the organic mold compound is selected from the group consisting of at least one ammonium cation selected from the group consisting of tetramethylammonium, tetraethylammonium, tetrapropylammonium, and tetrabutylammonium, An ammonium salt bonded with a hydroxide, bromine or chlorine; Wherein the catalyst is selected from the group consisting of n-butylamine, ethylamine, isopropylamine or ethylenediamine. The method of claim 1, wherein the aluminum precursor is one or more selected from the group consisting of sodium aluminate, aluminum nitrate, aluminum sulfate, and aluminum isopropoxide. &Lt; / RTI &gt; wherein the cobalt supported catalyst is supported on a support. The method of claim 1, wherein the molar ratio of aluminum to silicon in the synthesis gel is 1: 5 to 50. The process for preparing a cobalt supported catalyst for a Fischer-Tropsch process according to claim 1, wherein the molar ratio of the organosilicon compound: silicon in the synthetic gel is 1: 0.1 to 1. A process for producing a cobalt supported catalyst for a Fischer-Tropsch process, comprising the steps of: preparing a cobalt supported catalyst for a Fischer-Tropsch process by the production process according to any one of claims 1 to 10; And
Preparing a synthetic liquid fuel from the syngas, with the cobalt supported catalyst for the Fischer-Tropsch process activated;
&Lt; / RTI &gt; 12. The method of claim 11, further comprising: a first step of applying a cobalt supported catalyst for a Fischer-Tropsch process to a reactor;
A second step of activating a cobalt supported catalyst for the Fischer-Tropsch process; And
A third step of producing a synthetic liquid fuel from the synthesis gas in the presence of the catalyst
&Lt; / RTI &gt; 13. The method of claim 12, wherein the second step comprises introducing hydrogen at 300-600 占 폚 to reduce the cobalt-containing catalyst component. 13. The method of claim 12, wherein the third step is carried out at a reaction temperature of from 200 to 270 &lt; 0 &gt; C.

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