KR101578192B1 - CoO particle-containing catalyst isolated for fischer-tropsch synthesis and GTL method using the same - Google Patents

Abstract

The present invention relates to a separate Fischer-Tropsch synthesis catalyst comprising CoO phase particles, a process for their preparation and a process for the production of liquid hydrocarbons from natural gas using them. The separated Fischer-Tropsch synthesis catalyst containing CoO phase particles prepared according to the present invention exhibits high activity even at a low reduction temperature since it has a high degree of dispersion and easily reduces. When the catalyst is applied to a Fischer-Tropsch synthesis reaction, it exhibits high conversion of carbon monoxide and stable selectivity of liquid hydrocarbons, inhibiting deactivation of the catalyst, and enabling development of a competitive GTL process.

Description

(CoO particle-containing catalyst for fischer-tropsch synthesis and GTL method using the same), and a method for producing liquid hydrocarbons from natural gas using the same.

The present invention relates to a separate Fischer-Tropsch synthesis catalyst comprising CoO phase particles, a process for their preparation and a process for the production of liquid hydrocarbons from natural gas using them.

In the development of GTL technology, which is being watched as an alternative to cope with recent rapid changes in oil prices, the improvement of FT synthesis catalysts is directly related to the enhancement of GTL technology's competitiveness. In particular, according to the improvement of the catalyst for FT reaction, thermal efficiency and carbon utilization efficiency of the GTL process can be improved and the FT reaction process can be optimized and designed. In order for such FT reaction there is a catalyst, such as iron and cobalt-based mainly used, the characteristics of the cobalt-based catalyst but are expensive disadvantage, flew low, high activity and long life and CO ₂ generated the yield of liquid paraffinic hydrocarbon It has a high advantage. In addition, since it can be used only as a low-temperature catalyst because of the problem of producing a large amount of CH ₄ at a high temperature, it must be dispersed well on a stable support having a high surface area such as alumina, silica and titania because expensive cobalt is used. , Re, and the like are additionally added.

The GTL process consists of three main processes, such as reforming of natural gas, FT synthesis of syngas, and reforming of product. Among these processes, iron and cobalt are used as catalysts at 200 to 350 ° C And the FT reaction performed at a pressure of 10 atm to 30 atm can be explained by four main reactions as follows.

(a) Chain growth in F-T synthesis

CO + 2H ₂ ? -CH ₂ - + H ₂ O? H (227 ° C) = -165 kJ / mol

(b) Methanation.

CO + 3H ₂ ? CH ₄ + H ₂ O? H (227 ° C) = -215 kJ / mol

(c) Water gas shift reaction

CO + H ₂ O? CO ₂ + H ₂ ? H (227 ° C) = -40 kJ / mol

(d) Boudouard reaction.

2CO → C + CO ₂ ΔH (227 ° C.) = -134 kJ / mol

Generally, the catalyst for FT synthesis is an oxide catalyst. Therefore, the reducing property of the catalyst for FT synthesis is one of the most important factors for determining the catalytic reaction.

Generally, the cobalt catalyst has a Co ₃ O ₄ phase. Before the FT reaction, cobalt oxide is reduced at 300-500 ° C. using hydrogen. The reduction process of cobalt oxide can be represented by the following two steps.

Step 1: Co ₃ O ₄ + 4H ₂ ? 3CoO + 4H ₂ O

Step 2: CoO + H ₂ → Co + H ₂ O

Conventional cobalt-based FT synthesis catalysts are prepared by impregnation or coprecipitation. In the case of the catalyst prepared by the above-mentioned method, a catalyst oxide is formed through calcination. That is, the catalyst has a Co ₃ O ₄ phase, and the catalyst has a strong interaction with the support, so that the reduction temperature of the cobalt oxide is high.

Korean Patent No. 10-1015492 discloses a catalyst preparation method different from the conventional catalyst preparation method. It is described that it is possible to control the selectivity of carbon monoxide by decreasing the interaction between the support and the active material while controlling the size of the active ingredient particles. However, the catalyst prepared by the method disclosed in the patent also has a Co ₃ O ₄ phase, which has a limitation in that it needs to undergo a two-stage reduction reaction before being used in the FT reaction.

An important factor determining the activity of the FT catalyst is the dispersion and reduction rate. When the particle size is small and the degree of dispersion is high, the stability of the FT catalyst is lowered, the catalyst activity is low, and the generation of methane is increased. In addition, when the particle size is too large and the reduction ratio is high, the activity of the catalyst is inhibited because of low dispersity. Therefore, a catalyst having an appropriate particle size and a high degree of dispersion and reduction can be regarded as an excellent catalyst.

The inventors of the present invention have been studying cobalt-based catalysts optimized for activity and liquid hydrocarbon selectivity, and have previously prepared cobalt nanoparticles containing CoO phase and supported them on a catalyst support to prepare a catalyst for Fischer-Tropsch synthesis The present invention has been accomplished on the basis of the fact that it exhibits high reducing properties and excellent dispersibility at low temperatures and exhibits excellent catalytic activity as compared with conventional methods. The present invention is based on this.

A first aspect of the present invention provides a catalyst for separate Fischer-Tropsch synthesis, comprising CoO phase particles.

A second aspect of the present invention is a method of manufacturing a cobalt particle including the steps of: preparing cobalt particles including a part or all of CoO phase particles; And supporting the prepared cobalt particles on a support. The present invention also provides a method for producing a catalyst for Fischer-Tropsch synthesis.

In a third aspect of the present invention, there is provided a method for preparing a catalyst for Fischer-Tropsch synthesis according to the present invention, comprising: a first step of reacting an aqueous solution of a cobalt precursor with a basic compound aqueous solution to form a precipitate; A second step of mixing the precipitate with capping molecules and a nonpolar organic solvent and heating the mixture; And a third step of recovering the organic solvent layer in the mixture and heating CoO phase particles at 230 to 350 ° C. The method comprising the steps of:

In a fourth aspect of the present invention, there is provided a method of producing liquid hydrocarbons from natural gas using a Fischer-Tropsch synthesis reaction, comprising the steps of: a) introducing a catalyst for Fischer-Tropsch synthesis according to the present invention into a Fischer- ) step; B) activating the separated Fischer-Tropsch synthesis catalyst comprising CoO phase particles with a catalyst for Fischer-Tropsch synthesis; And c) performing a Fischer-Tropsch synthesis reaction by the activated Fischer-Tropsch synthesis catalyst.

Hereinafter, the present invention will be described in detail.

Since conventional cobalt catalysts are produced in Co ₃ O ₄ phase, they must be activated to cobalt metal (Co) by reduction under a hydrogen atmosphere at high temperature of 300 - 500 ° C before FT reaction after application to FT reactor do.

The present invention is characterized in that the catalyst for Fischer-Tropsch synthesis before the application to the FT reactor and / or the catalyst active component carried on the support are cobalt particles containing some or all of the CoO phase particles. The catalyst according to the present invention can be reduced to hydrogen and activated without any firing process. The reduction may be performed in a hydrogen atmosphere at a temperature ranging from 100 ° C to 500 ° C after the catalyst is applied to a fixed bed, a fluidized bed, or a slurry reactor. In addition, the catalyst for Fischer-Tropsch synthesis according to the present invention exhibits high activity even at a low reduction temperature, and can inhibit high conversion of carbon monoxide, stable selectivity to liquid hydrocarbons, and inactivation of the catalyst.

In the present invention, the term "separated Fischer-Tropsch synthesis catalyst" means a catalyst state that can be directly synthesized and transported and / or circulated before being applied to a reactor for Fischer-Tropsch synthesis. The catalyst for the synthesis of Tropsch synthesized in the CoO phase before application to the reactor for Fischer-Tropsch synthesis, then applied to the reactor for the synthesis of Fischer-Tropsch, And becomes a synthesis catalyst.

In addition, since the present invention can prepare a cobalt-based catalyst component in an optimal size before being applied to an FT reactor, and can be made into a nanoparticle containing a CoO phase and supported on a catalyst support, This can easily happen.

In the present invention, the average diameter of the CoO phase particles may be in the range of 5 to 50 nm, and more preferably in the range of 10 to 20 nm. If it is less than 10 nm, it is difficult to reduce to a metal, which is the active site of Fischer-Tropsch reaction, by interaction with the catalyst support. Thus, the activity as a catalyst is lowered, the selectivity to liquid hydrocarbons is reduced, while the production of methane, a by-product, increases. On the other hand, when it exceeds 20 nm, the bulk volume becomes larger than the catalyst surface area, so that the surface area of the catalytic action point becomes relatively small and the activity of the catalyst is reduced.

In the present invention, the content of the CoO phase particles may be 10 parts by weight to 100 parts by weight based on 100 parts by weight of the catalyst.

The catalyst for Fischer-Tropsch synthesis according to the present invention comprises: preparing cobalt particles containing part or all of CoO phase particles; And supporting the prepared cobalt particles on a support.

The content of the CoO phase particles supported on the support is preferably 3 to 40 parts by weight, more preferably 5 to 35 parts by weight based on 100 parts by weight of the support. When the amount is less than 3 parts by weight, there is a problem that reactivity is reduced because there is not enough active ingredient to exhibit reactivity upon Fischer Tropsch. On the other hand, if it exceeds 40 parts by weight, there is a problem in that the cost of the catalyst is increased, the economical efficiency is lowered, the particle size of the catalyst is increased, and the specific surface area of the catalyst is decreased.

The support may be gamma-alumina, silica, titania, modified gamma-alumina, modified silica, modified titania, or mixtures thereof.

In the present invention, the catalyst may further include a noble metal selected from the group consisting of platinum, ruthenium, rhenium, or a mixture thereof. The noble metal acts as a cocatalyst to improve the activity of the catalyst. The content of the noble metal is preferably 0.01 part by weight to 1 part by weight based on 100 parts by weight of the catalyst.

The method for preparing a catalyst for Fischer-Tropsch synthesis according to the present invention comprises the steps of: a) forming a precipitate by reacting an aqueous solution of a cobalt precursor with an aqueous solution of a basic compound; A second step of mixing the precipitate with capping molecules and a nonpolar organic solvent and heating the mixture; And a third step of recovering the organic solvent layer in the mixture and heating at 230 to 350 ° C to form CoO phase particles.

Specifically, when a cobalt-containing precipitate is formed by reacting a cobalt-containing precursor aqueous solution with a basic compound aqueous solution, the cobalt-containing precipitate slurry obtained by washing with a deionized water is mixed with a capping molecule and a nonpolar organic solvent and heated, It is dissolved with an organic solvent and separated from the aqueous solution layer. Subsequently, the organic solvent layer is recovered and heated at 230 ° C to 350 ° C to form particles containing the CoO phase, wherein the particle size can be adjusted to a desired size.

Non-limiting examples of cobalt feed precursor in the first step is cobalt nitrate _{(Co (NO 3) 2 ·} H 2 O), cobalt chloride _{(CoCl 2 · H 2 O)} , cobalt sulfate (CoSO _4), acetate, cobalt (Co (AC) ₂ ) and mixtures thereof.

Non-limiting examples of basic compounds in the first step include ammonia, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, Lt; / RTI >

Non-limiting examples of capping molecules in the second step may be saturated or unsaturated C ₆ -C ₃₀ organic acids or fatty acids. More specifically, it includes 2-ethylhexanoic acid, stearic acid, lauric acid, linoleic acid, palmitic acid, oleic acid, Polyacids, derivatives thereof, and the like, or a mixture of two or more of them may be used.

In the second step, the capping molecules are preferably used in a molar ratio of 0.1 to 2.5 to 1 mole of the cobalt feed precursor. If the molar ratio is less than 0.1, the complete capping is not achieved and the dispersibility becomes poor, and the loss of the catalyst component in the aqueous solution may occur. On the other hand, if the molar ratio exceeds 2.5, the fluidity of the colloidal solution of the capped catalyst component may be deteriorated.

In the second step, the nonpolar organic solvent preferably has a melting point of less than 30 캜 and a boiling point of 70 캜. This is to maintain the reaction temperature suitable for the surface treatment. Non-limiting examples of nonpolar organic solvents may be toluene, xylene, paraffin, 1-hexadecane and common petroleum solvents such as kerosene, light oil or heavy oil.

The preferred heating temperature range in the third step is 230 to 350 占 폚, more preferably 230 to 300 占 폚. If the temperature is less than 230 ° C, CoO is not formed and the crystallization reaction is weak, resulting in a problem that the crystal size is too small. Also, when the temperature exceeds 350 ° C, the size of the crystal becomes too large to be suitable as a nano catalyst.

Further, the solution containing the formed CoO phase particles may be mixed with a polar organic solvent to precipitate and extract the capped particles, and then re-dispersing the capped particles to obtain cobalt oxide (CoO) particles dispersed in the organic solvent. Non-limiting examples of the polar organic solvent used as the extraction solvent may be methanol, ethanol, acetone, acetonitrile or a mixture thereof.

The cobalt particles can be redispersed in a nonpolar solvent and then impregnated into a support to support the cobalt particles containing some or all of the CoO phase particles on the support. At this time, it is preferable to use a solvent having a low boiling point as the non-polar solvent. The nonpolar solvent is removed at a temperature of from room temperature to 70 ° C and the supported catalyst is dried at a temperature of from 80 to 200 ° C to finally produce a catalyst for synthesis of Fischer-Tropsch supported on a support.

The present invention provides a method for producing liquid hydrocarbons from natural gas using a Fischer-Tropsch synthesis reaction, comprising the steps of: a) applying a Fischer-Tropsch synthesis catalyst according to the present invention to a Fischer-Tropsch synthesis reactor; B) activating the separated Fischer-Tropsch synthesis catalyst comprising CoO phase particles with a catalyst for Fischer-Tropsch synthesis; And c) performing a Fischer-Tropsch synthesis reaction by the activated Fischer-Tropsch synthesis catalyst.

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

On the other hand, the Fischer-Tropsch synthesis reactor may be a fixed bed, fluidized bed or slurry reactor.

According to the present invention, when a catalyst for Fischer-Tropsch synthesis containing part or all of CoO phase particles is used, the step b) is performed by reducing the catalyst for Fischer-Tropsch synthesis under a hydrogen atmosphere without any firing step .

The step b) is preferably carried out in a hydrogen atmosphere at 100 ° C to 500 ° C.

On the other hand, the step (c) corresponding to the Fischer-Tropsch synthesis reaction can be performed at a temperature of 200 ° C to 350 ° C, a reaction pressure of 5 to 30 kg / cm ² , and a space velocity of 1000 to 10000 h ^-1 , but is not limited thereto.

The Fischer-Tropsch synthesis reaction is preferably carried out while maintaining the hydrogen / carbon monoxide reaction ratio at 1 to 25 molar ratio.

In addition, the method for producing a liquid hydrocarbon according to the present invention may further comprise a step of reforming the Fischer-Tropsch synthesis reaction product after step c).

According to the present invention, by using the catalyst for Fischer-Tropsch synthesis according to the present invention, high activity is exhibited even at a low reduction temperature, and high conversion of carbon monoxide, stable selectivity to liquid hydrocarbons, and inactivation of the catalyst can be suppressed.

As a result of the Fischer-Tropsch synthesis reaction after the reduction of the catalyst according to the present invention, the liquid hydrocarbon was improved in the degree of cobalt oxide reduction and CO selectivity and the C5 + carbon selectivity in the Fischer-Tropsch synthesis reaction.

The separated Fischer-Tropsch synthesis catalyst containing CoO phase particles prepared according to the present invention exhibits high activity even at a low reduction temperature since it has a high degree of dispersion and easily reduces. When the catalyst is applied to a Fischer-Tropsch synthesis reaction, it exhibits high conversion of carbon monoxide and stable selectivity of liquid hydrocarbons, inhibiting deactivation of the catalyst, and enabling development of a competitive GTL process.

FIG. 1 is a transmission electron microscope (TEM) photograph of the cobalt oxide nanoparticles prepared in Examples and Comparative Examples (a: Example 1, b: Example 2, c: Example 3, .
2 shows X-ray diffraction patterns (XRD) of the nanoparticles prepared in each of the examples and comparative examples (a: Example 1, b: Example 2, c: Example 3, .
FIG. 3 is a transmission electron micrograph of a catalyst in which cobalt oxide nanoparticles prepared in Examples and Comparative Examples were supported on a gamma-alumina support (a: Example 1, b: Example 2, d: Comparative Example 1).
Fig. 4 shows X-ray diffraction patterns (XRD) of the catalysts in which the cobalt oxide nanoparticles prepared in Examples and Comparative Examples were supported on a gamma-alumina support (a: Example 1, b: Example 2, c : Example 3, d: Comparative Example 1).

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for further illustrating the present invention, and the scope of the present invention is not limited by these examples.

Example  One: CoO ≪ / RTI > 100% < RTI ID = 0.0 > (5% Co / Al ₂ O _{3  -} CoO  100%)

1-1. Preparation of cobalt oxide nanoparticles

A solution of 30 g of cobalt nitride (Co (NO ₃ ) ₂ .H ₂ O) in 200 mL of distilled water was added to a solution of 15.3 g of ammonium hydroxide (NH ₄ OH) in 28 mL of distilled water. A slurry precipitate was obtained through precipitation reaction with stirring. The resulting precipitate was filtered and washed three times with 1500 mL of distilled water. The washed precipitate was dispersed again in distilled water to prepare a cobalt hydroxide slurry (cobalt hydroxide content: 10%) solution.

19.0 g of 1-hexadecane and 7.1 g of oleic acid were mixed in the prepared aqueous solution of cobalt hydroxide slurry and stirred at 100 DEG C for 30 minutes. During stirring, cobalt hydroxide reacted with oleic acid to cap the surface of oleic acid, which was dissolved in 1-hexadecane, a non-polar solvent, and separated into a water-receiving layer and an oil layer. The aqueous layer of the upper layer was simply separated and removed, and the oil layer containing the capped cobalt was recovered. The recovered solution was heated at 300 캜 for 3 hours to prepare cobalt oxide nanocrystals of CoO phase.

A transmission electron microscope (TEM) photograph of the nanoparticles of the prepared cobalt oxide is shown in FIG. 1 (a). The TEM image of FIG. 1 (a) shows that the average size of the prepared cobalt oxide particles was 13.7 nm. Also, the average size of cobalt oxide was calculated using the Debye-Scherrer equation, which was 15.4 ㎚, similar to the TEM results.

The X-ray diffraction analysis (XRD) of the prepared cobalt oxide nanoparticles is shown in Fig. 2 (a). As a result, only the peak corresponding to the CoO phase was observed, confirming that the cobalt nanoparticles of Example 1 were all composed of the CoO phase.

1-2. Supporting the prepared cobalt oxide nanoparticles

The prepared cobalt oxide nanoparticle solution was mixed with 100 mL of methanol to coagulate-precipitate the cobalt oxide nanoparticles, which was then separated from the 1-hexadecane solvent. The separated nanoparticles were mixed with hexane to prepare a colloid solution having a concentration of cobalt nanoparticles of 5 wt%.

10 g of the 5 wt% cobalt oxide nanoparticle solution thus prepared was impregnated with 10 g of gamma-alumina (Al ₂ O ₃ , specific surface area: 320 m ² / g) as catalyst support. The hexane solvent was evaporated at 50 占 폚 and dried in an oven at 100 占 폚 to prepare a catalyst. The composition of the prepared catalyst is 5% Co / Al ₂ O ₃ .

The TEM image of the catalyst supported on the support is shown in Fig. 3 (a), and the XRD pattern is shown in Fig. 4 (a). 3 (a), it was confirmed that the cobalt oxide nanoparticles were uniformly supported on the support.

Example  2: CoO With 70% Co ₃ O ₄ Preparation of cobalt catalyst consisting of 30% phase (5% Co / Al ₂ O _{3 -} CoO  70%)

Cobalt nanoparticles were prepared in the same manner as in Example 1, except that the oil layer containing the capped cobalt of Example 1 was heated at 270 ° C. for 3 hours.

A transmission electron microscope (TEM) photograph of the nanoparticles of the prepared cobalt oxide is shown in FIG. 1 (b). From the TEM photograph of FIG. 1 (b), it was confirmed that the average size of the prepared cobalt oxide particles was 14.2 nm. In addition, the average size of cobalt oxide was calculated using the Debye-Scherrer equation, which was found to be 15.2 ㎚, similar to the TEM result.

The X-ray diffraction (XRD) of the prepared cobalt oxide nanoparticles is shown in FIG. 2 (b). As a result, the peak corresponding to the CoO phase and the peak corresponding to the Co ₃ O ₄ phase all appeared, and it was confirmed that the content of the CoO phase was 70% through the distribution of the peak.

The support of the prepared cobalt nanoparticles was also carried out in the same manner as in Example 1. TEM images and X-ray diffraction analysis images of the supported cobalt nanoparticles are shown in FIGS. 3 (b) and 4 (b), respectively.

Example  3: CoO With 30% Co ₃ O ₄ Gt; Co / Al < / RTI > ₂ O _{3 -} CoO  30%)

Cobalt nanoparticles were prepared in the same manner as in Example 1, except that the oil layer containing the capped cobalt of Example 1 was heated at 230 캜 for 3 hours.

A transmission electron microscope (TEM) photograph of the nanoparticles of the prepared cobalt oxide is shown in FIG. 1 (c). From the TEM photograph of FIG. 1 (c), it was confirmed that the average size of the prepared cobalt oxide particles was 14.5 nm. In addition, the average size of cobalt oxide was calculated using the Debye-Scherrer equation, which was found to be 15.2 ㎚, similar to the TEM result.

The X-ray diffraction (XRD) of the prepared cobalt oxide nanoparticles is shown in Fig. 2 (c). As a result, the peak corresponding to the CoO phase and the peak corresponding to the Co ₃ O ₄ phase all appeared, and it was confirmed that the content of the CoO phase was 30% through the distribution of the peak.

The support of the prepared cobalt nanoparticles was also carried out in the same manner as in Example 1. TEM images and X-ray diffraction analysis images of the supported cobalt nanoparticles are shown in FIGS. 3 (c) and 4 (c), respectively.

Comparative Example  One: Co ₃ O ₄ (100%) Preparation of cobalt-based catalysts

Cobalt nanoparticles were prepared in the same manner as in Example 1, except that the oil layer containing the capped cobalt of Example 1 was heated at 200 占 폚 for 3 hours.

A transmission electron microscope (TEM) photograph of the nanoparticles of the prepared cobalt oxide is shown in FIG. 1 (d). 1 (d), it was confirmed that the average size of the prepared cobalt oxide particles was 14.8 nm. Also, the average size of cobalt oxide was calculated using the Debye-Scherrer equation, which was confirmed to be 15.7 ㎚, similar to the TEM result.

2 (d) shows the X-ray diffraction analysis (XRD) of the above-prepared cobalt oxide nanoparticles. As a result, only the peak corresponding to the Co ₃ O ₄ phase was observed, confirming that all of the cobalt nanoparticles of Comparative Example 1 were composed of only Co ₃ O ₄ phase.

Comparative Example  2: Conventional On impregnation  Fisher- Tropsch  Preparation of synthesis catalyst

26.9 g of gamma-alumina was added to a solution of 20 mL of tertiary distilled water and 14 g of cobalt nitrate (Co (NO ₃ ) ₂ .6H ₂ O). The slurry was dried at 100 ° C. for 12 hours or more and then calcined at 500 ° C. in an air atmosphere for 5 hours to prepare a 10% cobalt / alumina catalyst.

Comparative Example  3: Conventional In coping  Fisher- Tropsch  Preparation of synthesis catalyst

Ammonium hydroxide (NH ₄ OH) in deionized water of 20 mL and 28% were prepared mixture of 2.9 g solution. To the slurry in which 50 mL of tertiary distilled water was mixed with 7 g of cobalt nitrate (Co (NO ₃ ) ₂ .6H ₂ O) and 26.9 g of gamma-alumina, the solution was added under vigorous stirring. The precipitated cobalt hydroxide-alumina slurry resulting from the addition was collected, filtered, and washed several times with 500 mL of distilled water. The slurry was dried at 100 ° C. for 12 hours or more and then calcined in an air atmosphere at 500 ° C. for 5 hours to prepare a 5% cobalt / alumina catalyst.

Experimental Example  One: CoO  Investigation of Catalyst Activity by Content

The Fischer-Tropsch reaction was performed using the catalysts prepared in Examples 1 to 3 and Comparative Examples 1 to 3, and the activity of each catalyst was compared and analyzed.

For the experiment, 0.5 g of each catalyst was charged into a 1/2-inch stainless steel fixed bed reactor and reduced for 5 hours under hydrogen (5 vol% H ₂ / He) atmosphere at 350 ° C. Reaction temperature 240 ℃, a reaction pressure of 10 kg / cm ^2, The molar ratio of carbon monoxide: hydrogen: argon (internal standard) was fixed at a rate of 31.5: 63.0: 5.5 at a space velocity of 3600 L / kg _cat / hr and injected into the reactor. The Fischer-Tropsch reaction was carried out and the activity of the catalyst was measured after 40 hours of reaction. The results are shown in Table 1 below.

division
catalyst The phase of noxious oxide Co dispersion
(%) Amount of hydrogen adsorption
(μmol / g)
* Cobalt oxide reduction degree
** CoO _X
Nanoparticle size (nm)
*** CO conversion (carbon mol%) Carbon selectivity
(carbon mol%) C ₁ C ₂ -C ₄ C _{5 +} Example 1 5% Co /? - Al ₂ O ₃ CoO 100% 4.0 15.9 73.1 14.8 64.4 18.4 11.8 69.8 Example 2 5% Co /? - Al ₂ O ₃ CoO 70%
Co ₃ O ₄ 30% 3.8 15.3 62.1 14.5 53.6 17.6 10.7 71.7 Example 3 5% Co /? - Al ₂ O ₃ CoO 30%
Co ₃ O ₄ 70% 3.5 14.1 48.7 14.2 36.6 16.8 8.9 74.3 Comparative Example 1 5% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% 3.3 13.2 43.2 13.7 29.4 16.0 8.7 75.3 Comparative Example 2 5% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% - 8.5 32.5 7.5 8.5 23.1 17.8 59.1 Comparative Example 3 10% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% - 7.1 45.6 <5 9.2 19.7 15.8 64.5

* The amount of the chemically adsorbed hydrogen at 100 ° C of the catalyst reduced at 350 ° C

** The degree of reduction of cobalt oxide calculated from the amount of oxygen chemically adsorbed at 350 ° C at 350 ° C

*** The size of the cobalt oxide measured by TEM of the prepared catalyst

The catalyst prepared in Examples 1 to 3 exhibited excellent catalytic activity despite the small amount of the supported catalyst of 5%, and the catalyst activity was higher as the CoO phase was larger. (Example 1> Example 2> Example 3).

As can be seen from the above table, Examples 1 to 3 containing the CoO phase exhibited Co ₃ O ₄ The hydrogen adsorption amount and the CO conversion were much better than those of Comparative Examples 1 to 3, which had only C5 + carbon selectivity.

It was also confirmed that the Co dispersion (3.5 to 4.0) of Examples 1 to 3 of the present invention is superior to the dispersion (3.3) of Comparative Example 1.

Therefore, it was confirmed that the Fischer-Tropsch catalyst containing the CoO phase according to the present invention had a higher hydrogen adsorption amount and CO conversion than the conventional catalyst.

Example  4: CoO 100% of cobalt nanoparticles are gamma- Alumina  To the support was added 10% Supported  Preparation of the catalyst (10% Co / Al ₂ O _{3  -} CoO  100%)

Cobalt nanoparticles were prepared in the same manner as in Example 1. The supported catalyst support was prepared in the same manner as in Example 1, except that 20 g of the nano-oxidized cobalt solution was taken and impregnated into 10 g of gamma-alumina.

Example  5: CoO 100% of cobalt nanoparticles are gamma- Alumina  20% Supported  Preparation of catalyst (20% Co / Al ₂ O _{3  -} CoO  100%)

Cobalt nanoparticles were prepared in the same manner as in Example 1. The supported catalyst support was prepared in the same manner as in Example 1, except that 40 g of the nano-oxidized cobalt solution was taken and impregnated with 10 g of gamma-alumina.

Example  6: CoO 100% of cobalt nanoparticles are gamma- Alumina  30% Supported  Preparation of catalyst (30% Co / Al ₂ O _{3  -} CoO  100%)

Cobalt nanoparticles were prepared in the same manner as in Example 1. The supported catalyst support was prepared in the same manner as in Example 1, except that 60 g of the nano-oxidized cobalt solution was taken and impregnated into 10 g of gamma-alumina.

Comparative Example  4: CoO 100% of cobalt nanoparticles are gamma- Alumina  To the support was added 2% Supported  Preparation of the catalyst (2% Co / Al ₂ O _{3  -} CoO  100%)

Cobalt nanoparticles were prepared in the same manner as in Example 1. The supported catalyst support was prepared in the same manner as in Example 1, except that a solution prepared by mixing 4 g of the nano-oxidized cobalt oxide solution and 10 g of hexane was taken and impregnated into 10 g of gamma-alumina.

Comparative Example  5: CoO 100% of cobalt nanoparticles are gamma- Alumina  50% Supported  Preparation of catalyst (50% Co / Al ₂ O _{3  -} CoO  100%)

Cobalt nanoparticles were prepared in the same manner as in Example 1. The supported catalyst support was prepared in the same manner as in Example 1, except that 100 g of the nano-oxidized cobalt solution was taken and impregnated with 10 g of gamma-alumina.

Experimental Example  2: Cobalt nanoparticles On the loading  Investigation of catalytic activity

The Fischer-Tropsch reaction was carried out in the same manner as in Experimental Example 1, except that the catalysts prepared in Examples 4 to 6 and Comparative Examples 4 to 5 were used. The results are shown in Table 2.

division
catalyst
The phase of noxious oxide Amount of hydrogen adsorption
(μmol / g)
* Cobalt oxide reduction degree
** CoO _X
Nanoparticle size (nm)
*** CO conversion (carbon mol%) Carbon selectivity
(carbon mol%) C ₁ C ₂ -C ₄ C _{5 +} Example 4 10% Co /? - Al ₂ O ₃ CoO 100% 30.2 76.2 14.9 72.7 13.3 9.3 77.4 Example 5 20% Co /? - Al ₂ O ₃ CoO 100% 57.4 78.6 15.0 83.7 12.1 8.8 79.1 Example 6 30% Co /? - Al ₂ O ₃ CoO 100% 81.6 79.4 15.3 89.6 10.9 8.4 80.7 Comparative Example 4 2% Co /? - Al ₂ O ₃ CoO 100% 5.1 69.2 14.7 25.1 21.2 15.7 63.1 Comparative Example 5 50% Co /? - Al ₂ O ₃ CoO 100% 69.30 80.5 15.5 69.3 8.9 6.6 84.5

* The amount of the chemically adsorbed hydrogen at 100 ° C of the catalyst reduced at 350 ° C

** The degree of reduction of cobalt oxide calculated from the amount of oxygen chemically adsorbed at 350 ° C at 350 ° C

*** The size of the cobalt oxide measured by TEM of the prepared catalyst

That is, as can be seen from the above table, when the loading amount of the cobalt nanoparticles was between 10% and 30%, the cobalt oxide reduction degree and CO conversion were excellent. In Examples 4 to 6, as the loading amount of CoO was increased, the catalyst activity and C5 + selectivity were increased. On the other hand, the catalyst activity and selectivity were decreased when the amount of cobalt nanoparticles loaded was too small (2%, Comparative Example 4), and when the loading amount of cobalt nanoparticles was large (50%, Comparative Example 5) CO conversion was lower than that of CO. That is, it was confirmed that the loading amount of the preferable cobalt nanoparticles was 10% to 30%.

Example  7: CoO 100% of the cobalt nanoparticles were added to the silica support in an amount of 10% Supported  Preparation of the catalyst (10% Co / SiO _{2  -} CoO  100%)

A catalyst was prepared in the same manner as in Example 4, except that silica (SiO _{2 ,} specific surface area 260 m ² / g, average pore diameter 10 nm) was used as the catalyst support.

Example  8: CoO 100% of the cobalt nanoparticles Titania  To the support was added 10% Supported  Preparation of the catalyst (10% Co / SiO _{2  -} CoO  100%)

A catalyst was prepared in the same manner as in Example 4, except that titania (TiO _{2 ,} specific surface area 120 m ² / g, average pore diameter 12 nm) was used as the catalyst support.

Example  9: CoO 100% of the cobalt nanoparticles SiO2 in Reformed  To the gamma-alumina support was added 10% Supported  Preparation of the catalyst (10% Co / 3% SiO ₂ / Al ₂ O _{3  -} CoO  100%)

4 g of ethanol, 0.36 g of distilled water and 1.06 g of tetraethyl orthosilicate (TEOS) were mixed. This was impregnated with 10 g of gamma-alumina and then heated to 80 ° C. The TEOS is hydrolyzed by the heat, the surface is modified by SiO ₂ gamma-alumina catalyst was prepared in the support chain _{3% SiO 2 / Al 2 O} 3.

A catalyst was prepared in the same manner as in Example 4, except that 3% SiO ₂ / Al ₂ O ₃ was used as the catalyst support.

Experimental Example  3: Investigation of catalyst activity according to the type of catalyst support

The Fischer-Tropsch reaction was carried out in the same manner as in Experimental Example 1, except that the catalysts prepared in Examples 7 to 9 were used. The results are shown in Table 3 below.

division
catalyst
The phase of noxious oxide Amount of hydrogen adsorption
(μmol / g)
* Cobalt oxide reduction degree
** CoO _X
Nanoparticle size (nm)
*** CO conversion (carbon mol%) Carbon selectivity
(carbon mol%) C ₁ C ₂ -C ₄ C _{5 +} Example 7 10% Co / SiO ₂ CoO 100% 31.7 78.7 15.2 68.2 10.2 7.3 82.5 Example 8 10% Co / TiO ₂ CoO 100% 27.2 73.1 14.6 61.2 12.7 9.5 77.8 Example 9 _{10% Co / 3% SiO 2} / γ-Al 2 O 3 CoO 100% 30.8 78.6 14.9 75.3 14.5 10.4 75.1

* The amount of the chemically adsorbed hydrogen at 100 ° C of the catalyst reduced at 350 ° C

** The degree of reduction of cobalt oxide calculated from the amount of oxygen chemically adsorbed at 350 ° C at 350 ° C

*** The size of the cobalt oxide measured by TEM of the prepared catalyst

As a result, it was confirmed that even when various materials (silica, titania, surface-modified support) were used as the catalyst support, the properties such as the hydrogen adsorption amount, the CO conversion, and the carbon selectivity of the catalyst of the present invention were excellent.

Example  10: Platinum Co-catalyst  adding

0.02 g of tetraamine platinum (II) nitrate, a platinum precursor, was dissolved in 6 g of distilled water to prepare a catalyst. (Example 10)

The Fischer-Tropsch reaction was carried out in the same manner as in Experimental Example 1, except that the catalyst containing the platinum co-catalyst prepared in Example 10 was used. The results are shown in Table 4 below.

division
catalyst
The phase of noxious oxide Amount of hydrogen adsorption
(μmol / g)
* Cobalt oxide reduction degree
** CoO _X
Nanoparticle size (nm)
*** CO conversion (carbon mol%) Carbon selectivity
(carbon mol%) C ₁ C ₂ -C ₄ C _{5 +} Example 10 0.1% Pt-10% Co / γ-Al ₂ O CoO 100% 33.9 82.5 14.6 90.3 15.2 11.2 73.6

* The amount of the chemically adsorbed hydrogen at 100 ° C of the catalyst reduced at 350 ° C

** The degree of reduction of cobalt oxide calculated from the amount of oxygen chemically adsorbed at 350 ° C at 350 ° C

*** The size of the cobalt oxide measured by TEM of the prepared catalyst

As a result, it was confirmed that the addition of the platinum catalyst improves the cobalt oxide reduction and CO conversion as compared with the catalyst without the platinum catalyst.

Experimental Example  4: By firing  Comparison of catalytic activity when reduced

The catalysts of Examples 1 to 4 were fired at a temperature of 400 ° C. for 5 hours to prepare catalysts of Comparative Examples 6 to 9, respectively. (Comparative Example 6: Catalyst Sintering of Example 1, Comparative Example 7: Catalyst calcination, Comparative Example 8: Catalyst calcination of Example 3, Comparative Example 9: Catalyst calcination of Example 4)

The Fischer-Tropsch reaction was carried out in the same manner as in Experimental Example 1, except that the catalysts prepared in Comparative Examples 6 to 9 were used. The results are shown in Table 5.

division
catalyst The phase of noxious oxide Co dispersion
(%) Amount of hydrogen adsorption
(μmol / g)
* Cobalt oxide reduction degree
** CoO _X
Nanoparticle size (nm)
*** CO conversion (carbon mol%) Carbon selectivity
(carbon mol%) C ₁ C ₂ -C ₄ C _{5 +} Comparative Example 6 5% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% 0.9 3.5 78.2 23.7 10.3 13.0 14.9 72.1 Comparative Example 7 5% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% 1.5 6.1 63.1 21.7 18.5 13.2 15.8 71.0 Comparative Example 8 5% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% 2.5 9.8 50.4 19.3 27.0 14.8 15.8 69.4 Comparative Example 9 10% Co /? - Al ₂ O ₃ Co ₃ O ₄ 100% - 12.2 44.8 35.4 35.4 15.2 16.0 68.8

As can be seen from the above table, when the catalysts prepared in Examples 1 to 4 were fired, all of the Co ₃ O ₄ phases were 100%. The catalyst composed of the Co ₃ O ₄ phase had a larger particle size than that before calcination, and the CO conversion was reduced to less than half of that before calcination. That is, it was confirmed that the calcined catalyst had lower catalytic activity than the calcined catalyst.

Also, it was confirmed that when the calcination was performed, the Co dispersion degree was remarkably decreased to less than 2.5. The dispersions of Examples 1 to 3 which were not fired were 3.5 or more, which is a remarkably small value, and it is judged that aggregation of the particles occurred through firing. That is, since the existing Co ₃ O ₄ catalyst must be sintered at a high temperature, the dispersion degree is lowered. However, it has been confirmed that the catalyst including the CoO phase of the present invention can be maintained in a high degree of dispersion because it is used without reduction.

Claims (18)

In a Fischer-Tropsch synthesis catalyst comprising cobalt oxide,
A catalyst for Fischer-Tropsch synthesis, which is prepared by supporting cobalt oxide particles containing a CoO phase on a support before separation of the cobalt oxide particles is carried out on a support or cobalt oxide particles containing a CoO phase.
The cobalt oxide particle according to claim 1, wherein the cobalt oxide particle containing the CoO phase has an XRD (XRD) content (content of CoO phase) / (Co ₃ O ₄ phase content) of more than 30/70 Fischer-Tropsch synthesis catalyst.
The catalyst for synthesis of Fischer-Tropsch according to claim 1, wherein the average diameter of the CoO phase-containing cobalt oxide particles is 5 to 50 nm.
The catalyst for synthesis of Fischer-Tropsch according to claim 1, wherein the CoO phase content is from 30 parts by weight to 100 parts by weight based on 100 parts by weight of cobalt oxide as a catalyst component.
[Claim 3] The Fischer-Tropsch catalyst according to claim 2, wherein the content of the catalyst component including the cobalt oxide particles including the CoO phase is 3 parts by weight to 40 parts by weight based on 100 parts by weight of the support.
3. The Fischer-Tropsch synthesis catalyst according to claim 2, wherein the support is selected from the group consisting of gamma-alumina, silica, titania, modified gamma-alumina, modified silica, modified titania and mixtures thereof.
The catalyst for synthesis of Fischer-Tropsch according to claim 1, wherein the catalyst further comprises a noble metal selected from the group consisting of platinum, ruthenium, rhenium or a mixture thereof.
The catalyst for synthesis of Fischer-Tropsch according to claim 7, wherein the content of the noble metal is 0.01 part by weight to 1 part by weight based on 100 parts by weight of the catalyst.
Preparing cobalt oxide particles including some or all of the CoO phase;
Supporting the prepared cobalt oxide particles on a support; And
Drying without additional firing step
And a catalyst for Fischer-Tropsch synthesis.
The method for producing a catalyst for Fischer-Tropsch synthesis according to claim 1,
A first step of reacting an aqueous solution of a cobalt-supplying precursor with an aqueous solution of a basic compound to form a precipitate;
A second step of mixing the precipitate with capping molecules and a nonpolar organic solvent and heating the mixture; And
Recovering the organic solvent layer in the mixture and heating at a temperature higher than 230 ° C. to 350 ° C. to form particles containing a CoO phase partially or wholly;
&Lt; / RTI &gt;
11. The method of claim 10, wherein the cobalt feed precursor is cobalt nitrate in step _{1 (NO (Co 3) 2} · H 2 O), cobalt chloride _{(CoCl 2 · H 2 O)} , cobalt sulfate (CoSO _4), acetic acid cobalt ( Co (AC) ₂ ) and mixtures thereof.
11. The method of claim 10 wherein in the first step the basic compound is selected from the group consisting of ammonia, sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, ammonium hydroxide, ammonium carbonate, ammonium bicarbonate, sodium carbonate, sodium bicarbonate, potassium carbonate, And mixtures thereof.
11. The process of claim 10, wherein the capping molecule in the second step is a saturated or unsaturated C ₆ -C ₃₀ organic acid or fatty acid.
11. The method of claim 10, wherein the capping molecules in the second step are used in a molar ratio of 0.1 to 2.5 based on 1 mole of cobalt feed precursor.
A method for producing liquid hydrocarbons from natural gas using a Fischer-Tropsch synthesis reaction,
A process for the Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 8, which is applied to a Fischer-Tropsch synthesis reactor;
B) reducing the catalyst for Fischer-Tropsch synthesis in a Fischer-Tropsch synthesis reactor under a hydrogen atmosphere without further calcination to activate it as a catalyst for Fischer-Tropsch synthesis; And
And performing the Fischer-Tropsch synthesis reaction by the activated Fischer-Tropsch synthesis catalyst.
delete 16. The process according to claim 15, wherein step b) is carried out in a hydrogen atmosphere at a temperature of from 100 DEG C to 500 DEG C.
16. The method of claim 15, c) steps 200 ℃ to 350 ℃, a reaction pressure of 5 to 30 kg / cm ^2, a space velocity of 1000 - The method is characterized in that is carried out at 10000 h ^-1.

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