KR20090070578A - Manufacturing method and device of fischer-tropsch catalyst with organic acid precursor and catalyst prepared thereof - Google Patents

Abstract

A method for producing a Fischer-Tropsch catalyst using organic acids and an apparatus using organic acids by the same are provided to increase activity of Fischer-Tropsch reaction, and to reduce manufacturing cost. A method for producing a Fischer-Tropsch catalyst using organic acids includes the following steps of: producing an organic acid solution by mixing carboxylic acid and water(S1); producing a compound by adding metallic iron and a co-catalyst in the organic acid solution(S2); oxidizing the compound and an oxidizer by spraying the compound and the oxidizer(S3); sintering oxide(S4); and adding electrostatic potential of 0.5 ~ 1.0 V to generate iron oxides(S5).

Description

Manufacturing method and device of Fischer-Tropsch Catalyst with Organic Acid Precursor and Catalyst Prepared Thereof}

The present invention relates to a method and apparatus for producing an iron catalyst widely used in Fischer-Tropsch catalysis, and to a catalyst prepared by the above. Fischer-Dropsch catalyst utilizing an organic acid as a precursor for producing an iron catalyst having a uniform and fine particle size of porous by forming an oxide by simultaneously spray contacting the mixture with the oxidant, and then sintering the resulting oxide. It relates to a production method, an apparatus for producing the same, and a catalyst produced by the production method.

In general, the coal indirect liquefaction system uses coal powder powder as a main raw material to finally produce waxy synthetic oil through gasification process-> refining process-> liquefaction process. In the liquefaction process, a Fischer-Tropsch process is applied in which the purified syngas is reacted on a catalyst and converted into liquid synthetic petroleum.

Fischer-Tropsh synthesis is a process that converts syngas (mainly composed of carbon monoxide and hydrogen) into hydrocarbon mixtures of varying chain lengths, from methane to wax, using a variety of catalysts. The hydrocarbon mixture includes saturated / unsaturated hydrocarbons, hydrocarbons having oxygenated bonds such as alcohols, ketones, aldehydes, and olefins containing double bonds. Among these various reaction products, in order to increase the selectivity of a specific material and to improve the overall reaction efficiency, development and research on the reaction process and the reaction catalyst are required. Particularly in the case of the catalyst, metal catalysts that are active in the Fischer-Tropsh reaction include Fe, Ni, Co, Ru and the like. Of these metals, Ru is too expensive to be used as a commercial catalyst, Ni is too high a methane production rate commercially only Fe and Co are used. Co catalyst has a problem of lowering activity in syngas containing a large amount of CO ₂ and producing a large amount of CH ₄ at a high temperature, so it can be used only as a low temperature catalyst. On the other hand, Fe catalyst is one of the most used catalysts because it is the lowest among Fischer-Tropsh catalysts, and the production of methane is low even at high temperatures and the selectivity of olefins in hydrocarbons is high.

The activity and selectivity of Fischer-Tropsch catalysts based on Fe tend to be improved through the addition of small amounts of promoters. Commonly used cocatalysts have been Cu and alkali metals such as Na, K, Ru and Cs. In the case of copper, the reduction of the iron oxide temperature is greatly reduced to suppress the sintering of the catalyst, and the alkali metal components lower the acidity of the iron oxide, thereby reducing the formation of unwanted methane and enhancing the selectivity for alkenes and waxes. Binders such as SiO ₂ and Al ₂ O ₃ increase the structural strength of iron catalysts and reduce frictional wear. However, since these binder components are generally acidic, they may result in increased selectivity to methane.

Various methods have been used to manufacture Fischer-Tropsch catalysts based on Fe. One method that was initially used by Fischer is “Iron Turning”, which produces a liquid product of oxygenated compounds at high pressures and hydrocarbons at low pressures. The catalyst thus prepared is rapidly deactivated and is not used much these days.

At present, the most widely used Fe-based catalyst production method is precipitation. The precipitation method is a method of producing an iron catalyst by reacting iron nitrate with a base such as ammonia or sodium carbonate. The slurry obtained by this reaction may be repeatedly washed and filtered to remove ammonium nitrate and tartrium nitrate, add a cocatalyst, and then dry and calcined to obtain a final iron catalyst.

Another method for producing the Fe-based catalyst is a melting method and a supporting method. The melting method is a method of manufacturing iron ore by melting it with one or more promoters such as SiO ₂ , Al ₂ O ₃ , CaO, MgO, K ₂ O. The catalyst thus prepared mainly takes the structure of magnetite (Fe ₃ O ₄ ) and has a disadvantage of having a very low surface area. As the magnetite is reduced to metal iron using hydrogen, a molten iron catalyst having catalytic activity can be obtained. Iron catalysts prepared by the melting method have high structural stability and are known to be very suitable for fluid bed reactors (Sasol). However, due to the relatively low surface area, the Fischer-Tropsch reaction activity is very low compared to the iron catalyst prepared by the precipitation method. The supporting method is a method for producing an iron catalyst by impregnating iron salts with metal oxides having excellent fire resistance such as Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ . As an impregnation method, the “incipient wetness technique” or the “excess wetting technique” are frequently used. The supported iron catalysts exhibit Fischer-Tropsch activity similar to that of iron catalysts prepared by precipitation based on the mass of iron used. However, when viewed on the basis of the total volume of the catalyst, it shows lower catalytic activity, and the supported iron catalyst has a disadvantage in that selectivity to unwanted methane is increased due to the acidity of the metal oxide.

Iron catalysts made by precipitation have been considered by far the best Fischer-Tropsch catalysts compared to the various production processes mentioned above. However, major disadvantages of the precipitation method include high manufacturing cost, labor intensity of the manufacturing method, and environmental hazards of the by-products. In the case of iron chloride or iron sulfate, iron used in the precipitation method is usually obtained from iron nitrate because it generates chlorine and sulfur, which are toxic and poison the catalyst. Iron nitrate is obtained by dissolving iron in nitric acid, removing impurities, and then repeatedly cleaning. Removing such impurities is a time-consuming and labor-intensive task, and is one of the major disadvantages of the precipitation method. In addition, the precipitation method has a disadvantage in that it is not easy to make spherical catalyst particles resistant to friction because they form iron hydroxide and iron hydride precursor having a very high viscosity.

Fischer-Tropsch catalyst production method using an organic acid as a precursor of the present invention for solving the above problems,

A method for producing a catalyst used in a Fischer-Tropsch synthesis reaction, the method comprising: preparing an aqueous organic acid solution in which carboxylic acid and water are mixed; Preparing a mixture by adding metal iron and a promoter to the organic acid aqueous solution; Spraying the mixture with an oxidant to oxidize; And sintering the oxidized oxide.

In addition, the catalyst production apparatus manufactured by the above production method,

Preparing an organic acid aqueous solution, adding a metal iron, a cocatalyst and a binder to the organic acid aqueous solution, oxidizing the mixture and an oxidizing agent, and sintering the oxidized oxide. In the manufacturing apparatus of the iron catalyst used for the Fischer-Dropsch catalyzed reaction, a mixture spraying sphere for spraying a mixture of a metal iron, a promoter and a binder in an aqueous organic acid solution, and is provided on both sides of the mixture spraying sphere, respectively An injection unit comprising an oxidant spraying port for spraying the oxidizing agent to pivot; An oxidation reaction unit configured to allow the oxidized reaction by mixing the mixture with the mixture while turning the sprayed mixture in one direction, the sprayed oxidizing agent rotating along an inner surface thereof; The cylinder is in communication with the oxidation reaction section and the collecting hole is formed in the lower portion, by applying a high heat to the oxide supplied from the oxidation reaction section to sinter the metal iron, the promoter and the binder and other materials, the weight of the sintered material is the effect of gravity A sintering reaction part for discharging to the lower collecting port; It is configured to include; a discharge port is formed at the end of the cylindrical body in communication with the sintering reaction portion to recover the fine sintered material from the sintering reaction portion.

As described in detail above, the Fischer-Dropsch catalyst production method using the organic acid as the precursor of the present invention, the production apparatus and the catalyst produced by the production method,

Since the catalyst is manufactured by a continuous process, it is possible to shorten the production time and increase productivity.

In addition, the iron catalyst obtained by the production method has a very good porosity and shows a high surface area, thereby enhancing the activity of the Fischer-Tropsch reaction.

In addition, the amount of water required for the cleaning process can be reduced by more than 90% by the existing precipitation method, and the particle crushing operation to make the particles fine and uniform is not required, thereby simplifying the process and reducing the manufacturing cost. It is now possible to provide useful methods and apparatus.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

As shown in FIG. 1, the method for preparing a catalyst according to the present invention includes preparing an organic acid aqueous solution in which carboxylic acid and water are mixed (S1); Adding a metal iron and a promoter to the organic acid aqueous solution to prepare a mixture (S2); Spraying the mixture and the oxidant to oxidize the reaction (S3); Sintering the oxidized oxide is made (S4).

The organic acid aqueous solution manufacturing step (S1) is a step of preparing an organic acid aqueous solution by mixing carboxylic acid and water. The organic acid refers to a carboxylic acid having at least one carboxyl functional group having a pKa value of 1 to 6 at room temperature, specifically, citric acid, salicylic acid, benzoic acid, maleic acid, malic acid, phthalic acid, or succinic acid. Mixed use.

Next, the mixture preparation step (S2) is a step of mixing iron, cocatalyst and a binder in the prepared organic acid solution. For example, the organic acid is slowly added to ultrapure water at room temperature while being agitated to make an aqueous organic acid solution, and then the metal iron is slowly added to the aqueous organic acid solution while being agitated. At this time, the metal iron reacts with the organic acid and the reaction temperature is increased by the heat of reaction. Therefore, the input speed of the metal iron should be made slowly enough so that the temperature of the reaction tank is not higher than 40 ℃. In general, when metal iron is reacted with an organic acid, it is known that hydrogen gas is generated as it is oxidized by an acid. At this time, since the generated hydrogen gas has an explosive property at 4.0wt% or more, it is necessary to dilute to 4.0wt% or less by properly mixing with air at the outlet.

As the above-mentioned iron, metal iron components in the form of thin flakes, grains and spherical powders having an average diameter of 1 to 500 mu m were used. Particles of 1 μm or less are difficult to handle due to heavy powdering, and particles of 500 μm or more are inefficient because the reaction time required to dissolve is too long.

The above-mentioned cocatalyst may be used in one kind or two or more kinds from the group consisting of copper, alkali metals and alkaline earth metals. The copper serves to suppress the deactivation of the catalyst by lowering the reduction temperature of the iron oxide, and the alkali metal composed of sodium, potassium, rubidium, cesium and mixtures thereof lowers the acidity of the iron oxide, thereby reducing the selectivity to unwanted methane. And enhance the selectivity to alkenes and waxes. Alkaline earth metals composed of magnesium, calcium, strontium, barium, and mixtures thereof increase the activity of the catalyst by increasing the reduction properties of iron oxides, such as copper.

The binder described above may be used in combination of one or more species from the group consisting of aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide. These are all metal oxides with excellent fire resistance and are added to improve the mechanical strength of the catalyst and the wear resistance against friction.

The content of the iron, the promoter and the binder is added to contain 30 to 70 wt% of iron, 0.002 to 40wt% of the promoter, and 0.01 to 40wt% of the binder based on the final catalyst product.

The oxidation reaction step (S3) is a step of forming a fine iron oxide by spraying a mixture of iron, a promoter and a binder dissolved in an organic acid with an oxidizing agent.

Wheel atomizer was used as the atomizer for spraying, and the speed of the wheel was adjusted so that the average diameter of the particles was spread evenly between 5 ~ 10㎛. When the particle size is 5 탆 or less, the wheel speed of the sprayer is unreasonable, and when it is 10 탆 or more, the efficiency of the subsequent oxidation reaction is lowered.

Referring to FIG. 2, in the manufacturing apparatus 100 in which the injection unit 10, the oxidation reaction unit 20, the sintering reaction unit 30, and the recovery unit 40 according to the present invention are arranged horizontally. The spray unit 10 is a mixture spray port 11 is formed to be sprayed to the center of the oxidizing reaction portion that is a cylindrical body, the oxidant spray ball 12 for spraying an oxidant such as compressed air to each side of the mixture spray ball is formed As such, the oxidant spray sphere 12 may be composed of a plurality so as to have an equiaxed outward from the center of the mixture spray sphere (11). In addition, the oxidant spray sphere 12 is sprayed to be spaced apart from the center rather than to be directly injected into the central mixture spray sphere 11 to make contact with the mixture while turning in the oxidation reaction unit (20). desirable. This is to solve this problem is not easily separated in the sintering reaction unit 30 to be described later by lowering the speed of the mixture and scattered to both sides when the oxidant is sprayed to the center.

The mixture and the oxidant introduced by the injection unit 10 are in contact with the fine particles in the oxidation reaction unit 20 to perform an oxidation reaction to generate iron oxide. At this time, the temperature of the oxidation reaction unit 20 in which the oxidation reaction is performed is maintained in the range of 250 ~ 300 ℃ to create the optimum conditions for producing iron oxide.

3a to 3d show the production conditions of the product according to the reaction temperature, the pH of the reactants and the electrical potential.

As shown, the higher the reaction temperature under the same conditions, the higher the probability of forming iron oxide. Therefore, in this manufacturing process was maintained above 250 ℃ to optimize the oxidation reaction. However, at 300 ° C. or higher, the carbon chain components may be sintered.

After the iron ion component is sufficiently reacted with oxygen, the iron oxide forms a precipitate and is directly introduced into the sintering reaction part 30 by gravity and the flow rate of air. At this time, by controlling the distance from the injection unit 10 to the inlet of the sintering reaction unit 30, it is possible to control the particle size of the iron oxide in the desired range. In other words, if the iron oxide particles are too large, they are precipitated before a specific distance by gravity, and at a particle size below that, the iron oxide is discharged to the outside through the outlet 41 of the recovery unit 40 after a specific distance. .

Therefore, the manufacturing apparatus 100 of the present invention may not only manufacture iron oxide having a fine size through fine contact between iron and an oxidant, but also uniformly distribute the particle size by adjusting the levitation distance of iron oxide.

In addition, the type and rate of oxidant is an important variable in determining the levitation distance of iron oxide. The oxidant may be used mixed with one or more species from the group consisting of air, compressed air, oxygen, hydrogen peroxide, organic peroxide, and ozone. And the flow rate of the oxidant and the spray rate of the mixture was adjusted so that the particle size at the inlet side of the sintering reaction side is 30 ~ 50㎛. At this time, the flow rate of the oxidant and the spray rate of the mixture is variable according to the size of the device, it is preferable to determine the flow rate and spray rate by the final particle size.

In addition, as shown in FIG. 4, an electrode device 50 is installed outside the oxidation reaction unit 20 to further increase the electric potential in the oxidation reaction step (S5) to promote the production of iron oxide. Can be. Here, the electric potential applied through the electrode device 50 may take a value of 0.5 to 1.0 V (SHE). If it is lower than 0.5V, the effect of the electric potential is insignificant, and if it is higher than 1.0V, iron oxide scale layer is formed on the surface of the reactor, reducing the reaction efficiency and causing the problem of reactor cleaning.

The sintering step (S4) is a sintering reaction unit 30 in communication with the oxidation reaction unit 20 to the iron oxide, cocatalyst oxide and binder of a specific particle size range in the oxidation reaction step as shown in Figure 1a and 2 By supplying high heat with supply, the carbon component of the organic acid mixed with oxides other than these oxides is sintered.

The temperature of the sintering reaction unit 30 is maintained in the range of 350 ~ 400 ℃ to sinter all except the iron oxide, the oxide of the promoter and the binder. The iron oxide, the promoter oxide, and the binder thus produced are recovered through the trap 31 formed at the bottom, and the particle size of the final catalyst product can generate a very uniform and fine catalyst in the range of 30 to 50 μm.

In addition, since the unreacted iron ions are hardly affected by gravity, they are discharged to the discharge port 41 of the recovery part 40 without being separated through the collection port of the sintering reaction part.

All or a part of the discharged material may be recirculated to be sprayed into the oxidation reaction unit 20 through the mixture spray port 11 of the injection unit 10. In this case, the recovered unreacted iron ions are partially mixed with the oxidizing agent because they have not undergone a special separation process, so they should be distinguished from mixing with the existing reactants when re-inserted into the oxidation reaction unit.

In the manufacturing method and apparatus of the present invention, all processes from the dissolution of iron to the organic acid to the sintering process are continuous processes, which can improve production efficiency and greatly reduce the amount of washing water used for time, labor and washing. In particular, in the case of washing water, the amount of water used can be reduced by 90% or more compared with the conventional precipitation method.

In addition, the above-mentioned example is only an example to demonstrate this invention. Therefore, it is obvious that the ordinary skilled in the art to which the present invention pertains uses the partial change with reference to the detailed description.

Figure 1a and 1b is a block diagram showing a method for producing a catalyst according to the present invention.

Figure 2 is a schematic diagram showing a catalyst manufacturing apparatus according to the present invention.

Figure 3a to 3d is a graph showing the production conditions of the product according to the reaction temperature, the pH of the reactants and the electric potential in the present invention.

Figure 4 is a schematic diagram showing a catalyst manufacturing apparatus equipped with an electrode device in the present invention.

<Explanation of symbols for the main parts of the drawings>

100: catalyst production apparatus

10: injection part

11: Mixture spray ball

12: oxidant spray ball

20: oxidation reaction part

30: sintered reaction part

31: collecting part

40: recovery unit

41: outlet

S1: step of preparing organic acid aqueous solution

S2: Mixture Preparation Step

S3: oxidation reaction step

S4: Sintering Step

S5: Electric Potential Weighting Step

Claims (16)

In the catalyst production method used in the Fischer-Tropsch synthesis reaction, Preparing an organic acid aqueous solution in which carboxylic acid and water are mixed (S1); Adding a metal iron and a promoter to the organic acid aqueous solution to prepare a mixture (S2); Spraying the mixture and the oxidant to oxidize the reaction (S3); Sintering the oxidized oxide (S4); Fischer-Dropsch catalyst manufacturing method using an organic acid comprising a. The method of claim 1, Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that the binder is further mixed in the mixture manufacturing step (S2). The method according to claim 1 or 2, Fischer-Dropsch catalyst manufacturing method using an organic acid characterized in that the step of adding an electric potential of 0.5 ~ 1.0V (SHE) value in order to easily produce iron oxide in the oxidation step (S3). The method according to claim 1 or 2, The carboxylic acid utilizes an organic acid, characterized in that it is used in one or more kinds or mixed from the group consisting of citric acid, salicylic acid, benzoic acid, maleic acid, malic acid, phthalic acid, succinic acid having at least one carboxyl functional group having a pKa value of 1-6 at room temperature A Fischer-Dropsch Catalyst Preparation Method. The method according to claim 1 or 2, The metal iron is Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that used in the form of one or two or more from the group consisting of thin flakes, grains, spherical powder form having an average diameter of 1 ~ 500㎛. The method according to claim 1 or 2, The cocatalyst is Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that used in one kind or a mixture of two or more from copper, alkali metals, alkaline earth metals. The method of claim 6, The alkali metal is used in one kind or a mixture of two or more from the group consisting of sodium, potassium, rubidium, cesium, The alkaline earth metal is Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that used in the mixed or one or more kinds from the group consisting of magnesium, calcium, strontium, barium. The method of claim 2, The binder is Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that used in the mixture of one or more species from the group consisting of aluminum oxide, silicon dioxide, titanium dioxide, zirconium dioxide. The method according to claim 1 or 2, Fischer-Dropsch catalyst production method using the organic acid, characterized in that the spray particle average diameter is between 5 ~ 10㎛. The method according to claim 1 or 2, The oxidizing agent Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that used in the mixture of one or more species from the group consisting of air, compressed air, oxygen, hydrogen peroxide, organic peroxide, ozone. The method according to claim 1 or 2, Fischer-Dropsch catalyst manufacturing method using an organic acid, characterized in that the oxidation reaction is made of a temperature of 250 ~ 300 ℃. The method according to claim 1 or 2, Fissure-Dropsch catalyst manufacturing method using an organic acid, characterized in that the sintering is made of a temperature of 350 ~ 400 ℃. The method of claim 2, The content of the iron, cocatalyst and binder is based on the final catalyst product 30 ~ 70wt% iron, 0.002 ~ 40wt% cocatalyst and 0.01 ~ 40wt% of the binder Fischer using an organic acid, characterized in that Dropsh catalyst production method. Preparing an organic acid aqueous solution, adding a metal iron, a cocatalyst and a binder to the organic acid aqueous solution, preparing a mixture, spraying the mixture and an oxidizing agent for oxidation reaction, and sintering the oxidized oxide. Fischer-Dropsch catalyst using an organic acid containing 30 ~ 70wt% iron, 0.002 ~ 40wt% cocatalyst, 0.01 ~ 40wt% binder. Preparing an organic acid solution, adding a metal iron, a cocatalyst and a binder to the organic acid solution, oxidizing the mixture by spraying the oxidant, and sintering the oxidized oxide. In the manufacturing apparatus of the iron catalyst used for the Fischer-Dropsch catalyzed reaction, It is composed of a mixture spray sphere (11) for spraying a mixture of a metal iron, a cocatalyst and a binder to the aqueous organic acid solution, and an oxidizer spray sphere (12) provided on both sides of the mixture spray sphere to spray the oxidant And the injection unit 10; Oxidation reaction unit 20 to the cylinder to advance the sprayed mixture in one direction, the sprayed oxidant is mixed with the mixture while turning along the inner surface to perform the oxidation reaction; The cylinder is in communication with the oxidation reaction portion and the collecting port 31 is formed in the lower portion, by applying high heat to the oxide supplied from the oxidation reaction portion to sinter the carbon component of the organic acid, metal iron, cocatalyst and the material other than the binder, The elevated sintered material is sintered reaction part 30 for discharging to the lower collecting port under the influence of gravity; Fischer-drop utilizing the organic acid, characterized in that it comprises a; the discharge port 41 is formed at the end of the cylinder communicating with the sintering reaction portion to recover the fine sintered material from the sintering reaction portion; Sh catalyst production equipment. The method of claim 15, Fischer-Dropsch catalyst production apparatus using the organic acid, characterized in that the electrochemical potential is made in the oxidation reaction unit by installing the electrode device 50 to the outside of the oxidation reaction unit 20.

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