WO2004085055A1

WO2004085055A1 - Catalyst for fischer-tropsch synthesis and process for producing hydrocarbon

Info

Publication number: WO2004085055A1
Application number: PCT/JP2004/003750
Authority: WO
Inventors: Nobuo Aoki; Hiroyuki Seki; Masakazu Ikeda
Original assignee: Nippon Oil Corporation
Priority date: 2003-03-26
Filing date: 2004-03-19
Publication date: 2004-10-07
Also published as: MY141118A; CN1764499A; AU2004224536A1; JPWO2004085055A1; AU2004224536B2; JP4911974B2; CN1764499B

Abstract

A catalyst for Fischer-Tropsch synthesis which attains a low selectivity to methane and a high probability of chain growth α in a region where the conversion of Co is high. The catalyst for Fischer-Tropsch synthesis is obtained by depositing two or more precursor compounds containing a metal selected among cobalt, nickel, and ruthenium on a silica-based support containing 0.03 to 0.30 mass % alkali metal and/or alkaline earth metal.

Description

Description Catalysts for Fischer-Tropsch synthesis and methods for producing hydrocarbons [Technical field]

The present invention relates to a catalyst for synthesizing a hydrocarbon from a synthesis gas containing hydrogen and carbon monoxide as main components, and a method for producing a hydrocarbon using the catalyst.

[Background technology]

The reaction of synthesizing hydrocarbons from synthesis gas containing hydrogen and carbon monoxide as main components is called Fisher-Tropsch synthesis (FT synthesis) and is well known in the past. This FT synthesis has been carried out using a catalyst obtained by supporting an active metal such as iron or cobalt on a carrier such as silica or alumina (see, for example, Japanese Patent Application Laid-Open No. See the gazette.)

The FT synthesis reaction is defined by such indicators as carbon monoxide conversion (CO conversion), methane selectivity and chain growth probability α. Low methane selectivity means that the methane formation reaction, which is a side reaction of the FT synthesis reaction, is kept low. In addition, the chain growth probability cd is a measure of the molecular weight of the hydrocarbon obtained, and the higher the chain growth probability _α (ie, closer to 1.0), the higher the molecular weight of the hydrocarbon obtained. . '

The FT synthesis product is usually produced as a clean liquid fuel through a subsequent hydrocracking step. Among clean liquid fuels, the demand for middle distillates such as kerosene and light oil has been particularly high in recent years.In order to increase the yield of these middle distillates, a low methane selectivity and a high chain growth probability α are required. Become. For this reason, in the industry, a high C F conversion rate, a low methane selectivity and a high α FT synthesis reaction have been set as development goals, and improvements in the FT synthesis catalyst have been promoted in order to achieve this goal.

However, as the CO conversion rate increases, the methane selectivity tends to increase, and the CO conversion rate and chain growth probability _α tend to trade off. In other words, catalysts with low methane selectivity and high chain growth probability α in the high CO conversion region are still being developed. Not. This is the biggest obstacle to full-scale commercialization of FT synthesis and the production of clean liquid fuels using it.

[Disclosure of the Invention]

An object of the present invention is to eliminate the obstacles to practical use of FΤ synthesis by providing a new FΤ synthesis catalyst having a low methane selectivity and a high chain growth probability α in a high CO conversion region. .

As a result of intensive studies, the present inventors have found that a silica-based support containing 0.03% by mass or more and 0.30% by mass or less of an alkali metal and an alkali metal or alkaline earth metal contains a precursor containing a specific active metal component. The present inventors have found that a catalyst supporting the metal using two or more kinds of solid compounds can solve the above-mentioned problems, and have completed the present invention.

That is, the present invention provides a precursor comprising an active metal selected from cobalt, nickel and ruthenium in a silica-based support containing at least 0.33% by mass and not more than 0.30% by mass of an alkali metal and / or an alkaline earth metal. The present invention relates to a Fischer-Tropsch synthesis catalyst obtained by supporting two or more compounds.

The present invention also relates to a metal carrier selected from the group consisting of copartite and a nickel-based carrier containing an alkali metal and / or an alkaline earth metal in an amount of 0.3% by mass or more and 0.3% by mass or less. The catalyst according to the above, characterized in that the catalyst is produced by supporting two or more kinds of precursor compounds containing, followed by drying and calcining.

Also, in the present invention, the alkali metal or alkaline earth metal is selected from one or more alkali metals selected from lithium, sodium, and iron or magnesium and calcium. The catalyst as described above, which is one or two kinds of alkaline earth metals.

Further, according to the present invention, a precursor compound containing a metal selected from cobalt, nickel, and ruthenium is used when the nitrate, hydrochloride, sulfate, formate, acetate, propionate, oxalate, or the like of the metal is used. The catalyst according to the above, wherein the catalyst is a compound selected from the group consisting of acetylacetonate.

Further, in the present invention, the supported amount of cobalt, nickel and ruthenium on the silica-based carrier is 3 to 50% by mass per metal. Medium.

Further, according to the present invention, the average particle diameter of the sily-force-based carrier is 10 μπ! ~ 10 mm, specific surface area of 100 ~ 500 m ² Zg.

The present invention also relates to a method for producing a hydrocarbon, comprising reacting hydrogen with carbon monoxide using the catalyst described above to synthesize a hydrocarbon. Hereinafter, the present invention will be described in detail.

In the present invention, the siliceous carrier refers to a carrier obtained by modifying silica or a carrier containing silica as a main component with an alkali metal and / or an alkaline earth metal. Lithium, sodium and potassium are preferred as alkali metals used to modify the silica. Further, magnesium or calcium is preferably used as the alkaline earth metal.

The method for modifying silica with an alkali metal and / or an alkaline earth metal is not particularly limited, but a commonly used modification method such as an impregnation method or a metal alkoxide method may be appropriately selected. it can. Among them, a particularly preferred modification method includes an impregnation method. In addition, among the impregnation methods, the Incipient method is the most preferable method.

After impregnating the silica with an alkali metal and / or an alkaline earth metal, the silica is modified with an alkali metal and / or an alkaline earth metal through steps such as drying and baking.

The drying treatment is not particularly limited, and includes, for example, natural drying in air, degassing drying under reduced pressure, and the like. Usually, the reaction is carried out at 100 to 200 ° C., preferably 110 to 150 ° C., for 0.5 to 48 hours, preferably 5 to 24 hours under an air atmosphere. The calcination treatment is usually performed at 300 to 600 ° C., preferably 400 to 450 ° C. in an air atmosphere. C, for 0.5 to 10 hours, preferably 1 to 5 hours.

The amount of the alkali metal Z or alkaline earth metal that modifies the silica is 0.03% by mass or more and 0.30% by mass or less, preferably 0.04% by mass or more, 20 mass% or less, more preferably 0.05 mass% or more and 0.13 mass% or less. The amount of alkali metal and / or alkaline earth metal is 0. When the amount is less than 0.3% by mass, the effect of modification does not lower the methane selectivity and the effect of increasing the chain growth probability a. On the other hand, when the amount is more than 0.3% by mass, the CO conversion decreases, which is not preferable. .

The silica used in the present invention is preferably a silica having an average pore size of 8 to 20 nm, more preferably a silica having an average pore size of 10 to 18 nm, and further preferably an average pore size of 11 to 10 nm. ~ 16 nm silica. Here, the average pore diameter is a value obtained by measurement by a nitrogen adsorption method.

The shape of the silica and the silica-based carrier is not particularly limited, and a shape suitable for the process to be used can be selected from various shaped products such as a spherical product, a crushed product, and a cylindrical molded product. There is no limitation on the average particle size of the carrier, and usually Ι Ο μπ!のもの 10 mm, preferably 50 (m〜5 mm) can be appropriately selected and used according to the process.

There is no particular limitation on the addition specific surface area of silica and silica-based support for use, usually ^{1 0 0~5 0 O m 2 Z} g, is found using those preferably ^{2 0 0~4 0 0 m 2 /} g . In the present invention, the precursor compound containing a metal selected from cobalt, nickel and ruthenium supported on a silica-based carrier refers to all compounds having the metal in the molecule in the form of a salt or a complex. . There are no particular restrictions on the type of compound, but preferred examples thereof include nitrates, hydrochlorides, sulfates, formates, acetates, propionates, oxalates, and acetylacetonate. The present invention is characterized in that two or more kinds of the above-mentioned precursor compounds containing an active metal are used. Normally, two kinds of precursor compounds are combined to avoid complicated work, but three or more kinds of precursor compounds may be combined as needed. In the present invention, the combination of the precursor compounds is not particularly limited, but preferred combinations of the two types include nitrate and formate, nitrate and acetate, and nitrate and acetyl acetate. Particularly preferred combinations include nitrate and formate, and nitrate and acetate. Most preferred combinations include nitrate and acetate. In the present invention, a specific amount of an alkali metal and / or an alkaline earth metal is contained in a silica-based carrier, and a specific precursor compound containing a specific active metal is contained.

By carrying two or more types, the effects of the present invention can be achieved.

In the present invention, as the active metal supported on the silica-based support, a metal selected from cobalt, nickel and ruthenium is used. Of these, cobalt and ruthenium are more preferable, and cobalt is most preferable. The active metal component is usually obtained by immersing a silica-based carrier in a solution containing two or more types of precursor compounds containing the metal, impregnating and supporting the precursor compound on the carrier, and then drying and calcining. After that, it is supported as a metal oxide on a silica carrier.

The drying treatment is not particularly limited, and includes, for example, natural drying in air, degassing drying under reduced pressure, and the like. Usually, under air atmosphere, 100 to 200 ° C, preferably 110 to: L50. (: 0.5 to 48 hours, preferably 5 to 24 hours. The baking treatment is usually performed at 300 to 600 ° C., preferably 400 to 450 ° C. in an air atmosphere. At 0.5 ° C., 0.5 to: L 0 h, preferably 1 to 5 h.

The amount of the active metal supported in the present invention is not particularly limited, but is usually 3 to 50%, preferably 5 to 40%, particularly preferably 5 to 50% by mass per metal with respect to the silica-based support. It is carried in the range of 10 to 30%. If the amount of the active metal carried is less than 3% by mass, the activity is insufficient. If the amount exceeds 50% by mass, the active metal is significantly aggregated, and the effect of the present invention may not be sufficiently exhibited. Absent.

If necessary, a promoter such as zirconia or lantania can be carried. The amount of these promoters is generally used in the range of 1 to 20% by mass per metal with respect to the silica-based carrier. By using the catalyst of the present invention, hydrocarbons can be synthesized from hydrogen and carbon monoxide with high CO conversion, low methane selectivity, and high _α .

When the catalyst of the present invention is subjected to an FT synthesis reaction, it is also preferably employed to carry out a reduction treatment with hydrogen or the like in advance.

The raw material for performing the FT synthesis reaction using the catalyst of the present invention is not particularly limited as long as it is a synthesis gas containing hydrogen and carbon monoxide as main components. It is desirable that the molar ratio of carbon is in the range of 1.5 to 2.5, preferably 1.8 to 2.2.

The catalyst of the present invention can be applied to any process known as a reaction process of FT synthesis, that is, a fixed bed, a supercritical fixed bed, a slurry bed, a fluidized bed, and the like. Beds, supercritical fixed beds and slurry beds can be mentioned. Particularly preferred processes include fixed beds and supercritical fixed beds, and most preferred processes include fixed beds.

The reaction conditions for the FT synthesis reaction are not particularly limited, and the reaction can be performed under known conditions. 'Normally, 200 to 280 ° C as reaction temperature, the gas space velocity can carry out the reaction in the range of h ¹ of 1 000-3000.

[Industrial applicability]

As described above, a silica-based support containing 0.03% by mass or more and 0.30% by mass or less of an alkali metal and Z or an alkaline earth metal contains a precursor compound containing a metal selected from cobalt, nickel, and ruthenium. By using the catalyst of the present invention obtained by carrying out drying and calcination treatment after supporting two or more kinds as a catalyst for FT synthesis, methane selectivity is low in a high CO conversion region, and chain The growth probability α enables a high FT synthesis reaction.

[Best Mode for Carrying Out the Invention]

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Example 1)

The average pore diameter 15. 2 nm, the silica 5. 0 g of specific surface area 32 Om ² Zg, silica 0.04 as acetic Natoriumu and metallic magnesium in an amount corresponding to 0.04 weight ^_0/0 of the silica as the metal Natoriumu An aqueous solution containing magnesium nitrate in an amount corresponding to mass% was impregnated by the Incipient Wetness method. After impregnation, the water was dried at 120 ° C overnight. After drying, bake at 450 ° C for 2 hours. To obtain a silica-based carrier. As a result of analyzing the content of alkali metal and alkaline earth metal in the silica-based support by a metal analyzer, the total content of alkali metal and alkaline earth metal was 0.08% by mass. An aqueous solution containing an amount of cobalt nitrate equivalent to 10.0% by mass as metal cobalt and an amount of cobalt acetate equivalent to 10.0% by mass as metal cobalt is impregnated into the silica-based carrier by an incipient wetness method. I let it. After impregnation, water was removed by drying at 120 ° C. After drying, the catalyst was obtained by calcining at 450 ° C for 2 hours. This catalyst was packed in a fixed bed flow reactor, and reduced at 400 ° C. for 2 hours under a hydrogen stream before the reaction. The next material mixed gas of hydrogen Z- carbon oxides 2Z1 (molar ratio) was supplied at a gas hourly space velocity 2000 h ^1, temperature 250 ° C, the reaction was started Te pressure IMP a smell. The gas composition at the outlet of the reaction section was analyzed over time by gas chromatography, and using this analysis data, the CO conversion, methane selectivity, and chain growth probability were calculated in accordance with ordinary methods. The results are shown in Table 1.

(Example 2)

The same operation as in Example 1 was performed except that silica having an average pore diameter of 12.8 nm and a specific surface area of 347 m ² / g was used, and the CO conversion, methane selectivity, and chain growth probability α were determined. . The results are shown in Table 1.

(Example 3)

It Contact Al force Li metal by using an aqueous solution containing an amount of nitric mug Neshiumu which corresponds to the amount of 0.02% by weight of silica as sodium acetate and metallic magnesium, which corresponds to 0.02 mass ^_0/0 of the silica as the metal Natoriumu The same operation as in Example 1 was carried out except that a silica-based carrier containing 0.04% by mass of the alkaline earth metal was obtained, and the CO conversion, methane selectivity, and chain growth probability α I asked. Table 1 shows the results.

(Example 4)

Sodium acetate in an amount equivalent to 0.08% by mass of silica as metal sodium And the use of an aqueous solution containing magnesium nitrate in an amount equivalent to 0.08% by mass of silica as the metallic magnesium, so that the content of alkali metal and alkaline earth metal is 0.16% by mass. The same operation as in Example 1 was performed except that the carrier was obtained, and the CO conversion, methane selectivity, and chain growth probability _α were obtained. The result

1 si / ο

(Example 5)

Al force Li metal and by using an aqueous solution containing an amount of nitric mug Neshiumu corresponding to 0.05 mass ^_0/0 of silica as sodium acetate and magnesium metal in an amount corresponding to 0.05 weight% of silica as the metal Natoriumu The same operation as in Example 1 was performed to obtain the CO conversion rate, methane selectivity, and chain growth probability α, except that a silica-based carrier containing 0.1% by mass of alkaline earth metal was obtained. Was. The result was ¾1.

(Example 6)

By using an aqueous solution containing sodium acetate in an amount equivalent to 0.12% by mass of silica as metallic sodium and magnesium nitrate in an amount equivalent to 0.12% by mass of silica as metallic magnesium, The same operation as in Example 1 was carried out except that a silica-based carrier containing 0.24% by mass of lithium metal and alkaline earth metal was obtained, and the CO conversion, methane selectivity, and chain growth probability were obtained. _α was determined. Table 1 shows the results.

(Comparative Example 1)

Silica-based support with an average pore diameter of 15.2 nm, specific surface area of 320 m ² Zg, and a total content of alkali metal and alkaline earth metal of 0.02% by mass, and 10.0% by mass as metallic cobalt An aqueous solution containing an equivalent amount of cobalt nitrate and an amount of cobalt acetate equivalent to 10.0% by mass as metal cobalt was impregnated by the Incipient Wetness method. After impregnation, water was removed by drying at 120 ° C overnight. After drying, the catalyst was obtained by calcining at 450 ° C for 2 hours. The catalyst is passed through a fixed bed flow. Prior to the reaction, the mixture was reduced in a stream of hydrogen at 400 ° C for 2 hours. Then the raw material mixed gas of hydrogen carbon monoxide 2/1 (molar ratio) was supplied at a gas hourly space velocity 2000 h ^1, temperature 250 ° C, the reaction was started at a pressure IMP a. The gas composition at the outlet of the reaction section was analyzed over time by gas chromatography, and the CO conversion rate, methane selectivity, and chain growth probability ct were calculated in accordance with ordinary methods using the analysis data. The results are shown in Table 1.

(Comparative Example 2)

Comparative Example 1 except that a silica-based carrier having an average pore diameter of 12.8 nm, a specific surface area of 347 m ² / g, and a total content of alkali metals and alkaline earth metals of 0.02% by mass was used. The same operation was performed to determine the CO conversion rate, methane selectivity, and chain growth probability _α . The results are shown in Table 1.

(Comparative Example 3)

By using an aqueous solution containing sodium acetate in an amount equivalent to 0.16% by mass of silica as the metal sodium and magnesium nitrate in an amount equivalent to 0.16% by mass of the silica as the magnesium metal, the alkali metal is used. The same operation as in Example 1 was carried out except that a silica-based carrier having an alkaline earth metal content of 0.32% by mass was obtained, and the CO conversion, methane selectivity, and chain growth probability a were obtained. Table 1 shows the results.

(Comparative Example 4)

The same operation as in Example 1 was carried out, except that only the cobalt nitrate in an amount equivalent to 20.0% by mass of the silica before modification was supported on the silica-based carrier as metallic cobalt, and the CΟ conversion rate and the methane selectivity were changed. And the chain growth probability α. The results are shown in Table 1. As is evident from Table 1, a precursor containing a metal selected from cobalt, nickel and platinum in a silica-based carrier containing 0.03% by mass or more and 0.30% by mass or less of an alkali metal and / or an alkaline earth metal. Carrying two or more compounds It can be seen that the catalyst obtained by (1) simultaneously satisfies high CO conversion, low methane selectivity, and high chain growth probability α.

Catalytic CO conversion,% methane selectivity,% chain growth probability α Example 1 89. 3 1 3.6. 89 Example 2 90. 0 14. 0 0.87 Example 3 84. 0 1 3.7 0.88 Example 4 85.0 13.6 0.98 Example 5 90.0 9.0 0.91 Example 6 83.3 14.0 0.89 Comparative Example 1 85.2 1 7.20 . 86 Comparative Example 2 90. 0 20. 0 0.81 Comparative Example 3 78. 0 1 1. 0 0.89 Comparative Example 4 64. 0 1 3.5 0.88

Claims

The scope of the claims

1. Alkali metal and Z or alkaline earth metal are not less than 0.03% by mass and 0.30% by mass. /. A Fischer-Tropsch synthesis catalyst obtained by supporting two or more precursor compounds containing a metal selected from cobalt, nickel and ruthenium on a silica-based support containing:

2. Two types of precursor compounds containing a metal selected from cobalt, nickel and ruthenium in a silica-based support containing at least 0.3% by mass and not more than 0.3% by mass of alkali metal and Z or alkaline earth metal. 2. The catalyst according to claim 1, wherein the catalyst is manufactured by carrying out drying and calcining after carrying the above.

3. The alkali metal and / or alkaline earth metal is at least one selected from lithium, sodium, and potassium, or at least one selected from magnesium and calcium. 3. The catalyst according to claim 1, wherein the catalyst is an alkaline earth metal.

4. The precursor compound containing a metal selected from cobalt, nickel and ruthenium is a nitrate, hydrochloride, sulfate, formate, acetate, propionate, oxalate, and acetyla of the metal. The catalyst according to any one of claims 1 to 3, wherein the catalyst is a compound selected from settonate.

5. The catalyst according to any one of claims 1 to 4, wherein the amount of cobalt, nickel and ruthenium supported on the silica-based support is 3 to 50% by mass per metal. .

6. The average particle size of the carrier is 10 μπ! ~ 1 0 mm, a specific surface area of ^{1 0 0~5 0 O ra 2 /} g in the claims the items 1 to 5 wherein the catalyst of any crab description, characterized in that.

7. A method for producing a hydrocarbon, comprising reacting hydrogen with carbon monoxide using the catalyst according to any one of claims 1 to 6 to synthesize a hydrocarbon.