WO2017131232A1

WO2017131232A1 - Catalyst for fischer-tropsch synthesis, method for producing catalyst for fischer-tropsch synthesis, and method for producing hydrocarbon

Info

Publication number: WO2017131232A1
Application number: PCT/JP2017/003202
Authority: WO
Inventors: 真由美横井; 英樹新宮; 泰博荒木; 正成秋山
Original assignee: Ｊｘエネルギー株式会社
Priority date: 2016-01-29
Filing date: 2017-01-30
Publication date: 2017-08-03
Also published as: JPWO2017131232A1; ZA201805068B; JP6741694B2

Abstract

Provided is a catalyst for Fischer-Tropsch synthesis comprising a reduced product of an unreduced catalyst that contains: a carrier comprising silica and zirconium oxide; and cobalt oxide loaded on the carrier. The hydrogen adsorption amount per unit mass at 100°C is 0.60 ml/g or more. When the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak resulting from TPR measurement of the unreduced catalyst is denoted by C₁ and the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak resulting from TPR measurement of the reduced product is denoted by C_2, the ratio C₂/C₁ is 0.01-0.13.

Description

Fischer-Tropsch synthesis catalyst, Fischer-Tropsch synthesis catalyst production method, and hydrocarbon production method

The present invention relates to a Fischer-Tropsch synthesis catalyst, a Fischer-Tropsch synthesis catalyst production method, and a hydrocarbon production method.

The reaction of synthesizing hydrocarbons from synthesis gas containing hydrogen and carbon monoxide as main components is called Fischer-Tropsch synthesis (FT synthesis) and is used for the production of fuels. As a catalyst used for this FT synthesis reaction, for example, Patent Document 1 discloses a catalyst in which an active metal such as cobalt or iron is supported on a support such as silica or alumina, and Patent Document 2 discloses cobalt or zirconium. Alternatively, a catalyst containing titanium and silica is disclosed.

JP-A-4-227847 JP 59-102440 A

An object of the present invention is to provide a catalyst for FT synthesis which is excellent in reaction activity for FT synthesis reaction and can maintain good reaction activity for a long period of time, and a method for producing the same. Another object of the present invention is to provide a hydrocarbon production method using the above-mentioned catalyst for FT synthesis.

One aspect of the present invention relates to a Fischer-Tropsch synthesis catalyst.

In one embodiment, the Fischer-Tropsch synthesis catalyst is composed of a reduction product of an unreduced catalyst including a support containing silica and zirconium oxide and a cobalt oxide supported on the support. Further, the Fischer-Tropsch synthesis catalyst of this embodiment has a hydrogen adsorption amount per unit mass at 100 ° C. of 0.60 ml / g or more. Further, in this embodiment, when the TPR measurement of the unreduced catalyst is performed, the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak is C ₁ and the TPR measurement of the reduced product (Fischer-Tropsch synthesis catalyst) The ratio C ₂ / C ₁ is 0.01 to 0.13, where C ₂ is the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak when performing.

The Fischer-Tropsch synthesis catalyst according to the above aspect has excellent reaction activity for the Fischer-Tropsch synthesis reaction and can maintain good reaction activity for a long period of time.

In the Fischer-Tropsch synthesis catalyst according to one embodiment, the degree of reduction of the cobalt atom represented by the formula (1) may be 80 to 95%.
Reduction degree of cobalt atom (%) = 100 × [mass of metallic cobalt atom] / [mass of all cobalt atoms] (1)

In one embodiment, the content of zirconium oxide in the unreduced catalyst may be 0.01 to 7% by mass based on the total mass of the unreduced catalyst.

Another aspect of the present invention relates to a production method for producing a Fischer-Tropsch synthesis catalyst.

In one embodiment, the production method includes a reduction step of obtaining a Fischer-Tropsch synthesis catalyst by reduction treatment of an unreduced catalyst. In this embodiment, the unreduced catalyst contains a support obtained by calcining a support precursor containing silica and a zirconium compound, and a cobalt oxide supported on the support. In this embodiment, the hydrogen adsorption amount per unit mass at 100 ° C. of the Fischer-Tropsch synthesis catalyst is 0.60 ml / g or more. In this embodiment, when the TPR measurement of the unreduced catalyst is performed, the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak is C ₁ , and the TPR measurement of the Fischer-Tropsch synthesis catalyst is performed. the hydrogen consumption in the temperature range from a peak top to peak end point of the main peak when the _{C 2} of a ratio _C 2 / _{C 1} is 0.01 to 0.13.

In the production method according to the above aspect, by performing the reduction treatment so as to satisfy the predetermined hydrogen adsorption amount and the ratio C ₂ / C ₁ in the reduction step, the reaction activity with respect to the Fischer-Tropsch synthesis reaction is excellent and good reaction activity is achieved. A Fischer-Tropsch synthesis catalyst that can be maintained for a long time can be obtained.

In one embodiment, the degree of reduction of the cobalt atom represented by the formula (1) of the Fischer-Tropsch synthesis catalyst may be 80 to 95%.
Reduction degree of cobalt atom (%) = 100 × [mass of metallic cobalt atom] / [mass of all cobalt atoms] (1)

In one embodiment, the zirconium content of the unreduced catalyst may be 0.01 to 7% by mass in terms of zirconium oxide based on the total mass of the unreduced catalyst.

In the production method according to one aspect, in the reduction step, the temperature is raised to a reduction temperature of 340 to 385 ° C. at a rate of temperature rise of less than 50 ° C./min while bringing a reducing gas into contact with the unreduced catalyst, The reduction treatment of the unreduced catalyst may be performed while maintaining the time.

In the production method according to one aspect, in the reduction step, the reducing gas may be brought into contact with the unreduced catalyst under the conditions of GHSV of 200 to 1200 h ⁻¹ and a linear velocity of less than 20 mm / s.

Still another aspect of the present invention relates to a method for producing hydrocarbons.

The method for producing hydrocarbon according to one aspect may include a step of obtaining hydrocarbon by reacting carbon monoxide and hydrogen gas in the presence of the Fischer-Tropsch synthesis catalyst.

A method for producing hydrocarbons according to one aspect includes a step of reacting carbon monoxide with hydrogen gas to obtain hydrocarbons in the presence of a Fischer-Tropsch synthesis catalyst produced by the above production method. Good.

According to the present invention, there are provided a catalyst for FT synthesis which is excellent in reaction activity for FT synthesis reaction and can maintain good reaction activity for a long period of time, and a method for producing the same. Moreover, according to this invention, the manufacturing method of the hydrocarbon using said catalyst for FT synthesis is provided.

A preferred embodiment of the present invention will be described below.

The Fischer-Tropsch synthesis catalyst according to the present embodiment (hereinafter sometimes referred to as “FT synthesis catalyst”) is composed of a reduced product of an unreduced catalyst containing a cobalt oxide. The amount of hydrogen adsorption per unit mass at 100 ° C. of the FT synthesis catalyst is 0.60 ml / g or more. In addition, the hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak when the TPR measurement of the unreduced catalyst is performed is C ₁ , and the main consumption when the TPR measurement of the reduced product (FT synthesis catalyst) is performed. when the hydrogen consumption in the temperature range from a peak top to peak end point of the peak was _{C 2,} the ratio _C 2 / _{C 1} is 0.01 to 0.13.

The catalyst for FT synthesis according to this embodiment has excellent reaction activity for FT synthesis reaction, and can maintain good reaction activity for a long period of time.

In the present specification, the hydrogen adsorption amount per unit mass of the FT synthesis catalyst at 100 ° C. is determined as follows using a metal dispersity measuring device (BEL-METAL-3 manufactured by Nippon Bell Co., Ltd.). It is done. First, the reduced FT synthesis catalyst (reduced product) is weighed in a dry box under an inert atmosphere and charged into a metal dispersion measuring device, and pretreated at 300 ° C. for 5 hours in an argon atmosphere, for example. Then, after cooling to 100 degreeC which is measurement temperature, hydrogen gas is made to adsorb | suck and the quantity of adsorbed hydrogen gas is calculated. Then, the amount of adsorbed hydrogen gas is divided by the mass of the FT synthesis catalyst to calculate the amount of hydrogen adsorbed per unit mass.

Further, in the present specification, the ratio C ₂ / C ₁ is determined as follows using a TPR (Temperature Programmed Reduction) measuring apparatus. First, with respect to the unreduced catalyst (cobalt atoms are all oxides, degree of reduction is 0%), TPR measurement is performed with a TPR measurement device, and the main peak end point is calculated from the temperature representing the point where the perpendicular is drawn from the peak top of the main peak. seeking integrated area of the hydrogen consumption in the range of temperatures that represent, this is the hydrogen consumption C _1. Next, for the FT synthesis catalyst, TRP measurement is performed with the TPR measurement device under the same conditions as the unreduced catalyst, and the temperature range representing the main peak end point from the temperature representing the point where the perpendicular is drawn from the peak top of the main peak seeking integrated area of the hydrogen consumption in, this is the hydrogen consumption C _2. The ratio C ₂ / C ₁ is calculated from the hydrogen consumption C ₁ and the hydrogen consumption C ₂ thus obtained.

The ratio C ₂ / C ₁ is preferably 0.10 or less, more preferably 0.08 or less. Further, the ratio C ₂ / C ₁ is preferably 0.015 or more, more preferably 0.018 or more.

In the Fischer-Tropsch synthesis catalyst, the degree of reduction of the cobalt atom represented by the formula (1) is preferably 80 to 95%, more preferably 87 to 92%. When the degree of reduction is such, the reaction activity for the FT synthesis reaction tends to be further improved.
Reduction degree of cobalt atom (%) = 100 × [mass of metallic cobalt atom] / [mass of all cobalt atoms] (1)

Hereinafter, a preferred embodiment of the unreduced catalyst and a preferred embodiment of the method for producing the FT synthesis catalyst will be described in detail.

(Unreduced catalyst)
The unreduced catalyst may include a support containing silica and zirconium oxide and a cobalt oxide supported on the support. Further, the unreduced catalyst may include a support obtained by firing a support precursor containing silica and a zirconium compound, and a cobalt oxide supported on the support.

The zirconium content in the unreduced catalyst may be 0.01 to 7% by mass in terms of zirconium oxide based on the total mass of the unreduced catalyst. A large amount of zirconia decreases the reducibility of cobalt and may lead to a decrease in initial activity. Therefore, it is preferably 0.1 to 6% by mass, more preferably 0.5 to 5.5% by mass. .

That is, the content of zirconium oxide in the unreduced catalyst may be 0.01 to 7% by mass, preferably 0.1 to 6% by mass, more preferably based on the total mass of the unreduced catalyst. 0.5 to 5.5% by mass.

The content of cobalt oxide in the unreduced catalyst is preferably 10 to 35% by mass, and more preferably 20 to 30% by mass based on the total mass of the unreduced catalyst. By using such an unreduced catalyst, a catalyst for FT synthesis having higher reaction activity can be obtained.

The unreduced catalyst may be granular, for example. The average particle size of the unreduced catalyst is preferably 10 μm to 10 mm, more preferably 10 μm to 5 mm, still more preferably 10 to 150 μm, and even more preferably 30 to 100 μm. The average particle size of the unreduced catalyst can be measured using a particle size distribution measuring device. For example, using Beckman Coulter Co., Ltd. Coulter Counter Multisizer 3, it is automatically measured and calculated by the electrical detection zone method (Coulter principle). Is done.

The unreduced catalyst may further contain a noble metal. As the noble metal, at least one of Pt, Pd, Au and Re is preferable, and Pt is more preferable. By containing a noble metal, the reduction of cobalt can be promoted. Thereby, the oxidation of cobalt metal by the water produced | generated during the Fischer-Tropsch synthesis reaction presumed to be a deterioration factor of the catalyst can be suppressed.

The amount of the noble metal supported is preferably 0.001 to 1% by mass, preferably 0.001 to 0.5% by mass, based on the total mass of the unreduced catalyst, in terms of the balance between the above effects and economy. It is more preferable that

The unreduced catalyst preferably has a mesopore volume of 0.35 cm ³ / g or more. The mesopore volume of the unreduced catalyst is calculated by the following method. First, in order to remove moisture adsorbed on the unreduced catalyst, for example, a pretreatment for evacuating at 300 ° C. for 5 hours is performed. About the catalyst after this pretreatment, BELSORP-max manufactured by Nippon Bell Co., Ltd. is used, and adsorption / desorption isotherms are automatically measured by a constant volume method gas adsorption method using nitrogen at a liquid nitrogen temperature (−196 ° C.). . The analysis software (BEL Master ^™ ) attached to the device can be used for data analysis. The measured nitrogen adsorption / desorption isotherm is automatically analyzed by the BJH method, and the meso-fine per unit mass of the unreduced catalyst is analyzed. The pore volume (cm ³ / g) is calculated. The BJH method is a method for obtaining an average pore diameter from a desorption isotherm, which is a relationship between the relative pressure when the adsorbate is desorbed and the amount of adsorption. (EP Barrett, LG Joyner, PH Halenda: J. Am. Chem. Soc., 73, 373 (1951).)

Mesopore volume of unreduced catalyst is more preferably 0.35 ~ 0.8cm ³ / g, further preferably 0.4 ~ 0.7cm ³ / g. When the unreduced catalyst is 0.35 cm ³ / g or more, catalyst deterioration at the initial stage of the reaction tends to be more significantly suppressed. On the other hand, when the mesopore volume of the unreduced catalyst is 0.8 cm ³ / g or less, catalyst wear hardly occurs, and catalyst deterioration due to wear loss during the reaction is sufficiently suppressed.

The unreduced catalyst preferably has a specific surface area of 100 m ² / g or more. The specific surface area of the unreduced catalyst is calculated by the following method. First, in order to remove moisture adsorbed on the unreduced catalyst, for example, a pretreatment for evacuating at 300 ° C. for 5 hours is performed. About the catalyst after this pretreatment, BELSORP-max manufactured by Nippon Bell Co., Ltd. is used, and adsorption / desorption isotherms are automatically measured by a constant volume method gas adsorption method using nitrogen at a liquid nitrogen temperature (−196 ° C.). . The analysis software (BEL Master ^™ ) attached to the device can be used for data analysis, and the measured nitrogen adsorption / desorption isotherm is automatically analyzed by the BET equation, and the surface area per unit mass of the unreduced catalyst. (M ² / g) is calculated.

The specific surface area of the unreduced catalyst is preferably 100 to 400 m ² / g, and more preferably 110 to 200 m ² / g. When the specific surface area is 100 m ² / g or more, catalyst deterioration at the initial stage of the reaction tends to be more significantly suppressed. On the other hand, when the specific surface area is 400 m ² / g or less, catalyst wear hardly occurs and catalyst deterioration due to wear loss during the reaction is sufficiently suppressed.

In the present embodiment, as the silica, at least one selected from the group consisting of colloidal silica, water glass, aerosil, aerogel, silica sol, silica gel, powdered silica, and silicate can be preferably used.

The specific surface area of silica is preferably 50 to 500 m ² / g, and more preferably 150 to 400 m ² / g. When the specific surface area is 50 m ² / g or more, aggregation of active metals such as cobalt tends to be suppressed. On the other hand, when the specific surface area is 500 m ² / g or less, the pore diameter is sufficiently large, and there is a tendency to prevent the pores from being blocked by the loading of the active metal.

The specific surface area of silica is calculated by the following method. First, in order to remove moisture adsorbed on silica, for example, a pretreatment for evacuation at 300 ° C. for 5 hours is performed. The pretreated silica is subjected to automatic measurement of adsorption and desorption isotherms by BELSORP-max manufactured by Nippon Bell Co., Ltd. using a constant volume method gas adsorption method using nitrogen at a liquid nitrogen temperature (−196 ° C.). . The analysis software (BEL Master ^™ ) attached to the apparatus can be used for data analysis, and the measured nitrogen adsorption / desorption isotherm is automatically analyzed by the BET equation to determine the surface area per unit mass of silica (m ² / g) is calculated.

The average pore diameter of silica is preferably 8 to 25 nm, more preferably 10 to 20 nm, and even more preferably 10 to 15 nm. When the average pore diameter is 8 nm or more, the reaction activity tends to be further improved. Further, when the average pore diameter is 25 nm or less, the surface area of the support becomes sufficiently large and aggregation of the supported metal tends to be sufficiently suppressed.

The average pore diameter of silica is calculated by the following method. First, in order to remove moisture adsorbed on silica, for example, a pretreatment for evacuation at 300 ° C. for 5 hours is performed. The pretreated silica is subjected to automatic measurement of adsorption and desorption isotherms by BELSORP-max manufactured by Nippon Bell Co., Ltd. using a constant volume method gas adsorption method using nitrogen at a liquid nitrogen temperature (−196 ° C.). . For analysis of data, analysis software (BEL Master ^™ ) attached to the apparatus can be used, and the measured nitrogen adsorption / desorption isotherm is automatically analyzed by the BJH method, and the average pore diameter of silica is calculated.

The carrier precursor can be prepared, for example, using an impregnation method typified by the Incipient Wetness method using silica and a zirconium compound.

The shape of silica is not particularly limited, but it can be used from various shapes such as a spherical product, a crushed product, and a cylindrical molded product, and a shape suitable for the process can be selected. The average particle diameter of the silica is not limited, and for example, a particle having a size of 5 μm to 10 mm, preferably 5 μm to 5 mm, more preferably 5 to 150 μm, and further preferably 10 to 100 μm is appropriately selected depending on the process. be able to. The average particle size of silica can be measured using a particle size distribution measuring device. For example, using a Coulter counter Multisizer 3 manufactured by Beckman Coulter, Inc., it is automatically measured and calculated by an electrical detection band method (Coulter principle). .

The carrier precursor may contain one or more selected from the group consisting of alumina, titania, magnesia, ceria, zirconia, and complex oxides as a carrier material other than silica. Examples of the composite oxide include silica-alumina, silica-titania, alumina-titania, silica-zirconia, alumina-zirconia, titania-zirconia and the like.

Zirconyl nitrate (ZrO (NO ₃ ) ₂ ), zirconium oxychloride (ZrOCl ₂ ), zirconium oxochloride (ZrO (OH) Cl), zirconyl sulfate (ZrOSO ₄ ), zirconyl acetate (ZrO (C) ₂ H ₃ O ₂ ) ₂ ), zirconyl ammonium carbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ), and the like. Among these, zirconyl ammonium carbonate, zirconyl nitrate, and zirconyl acetate are preferable. A zirconium compound can be used individually by 1 type or in combination of 2 or more types.

As a method for preparing the carrier precursor, an impregnation method typified by the Incipient Wetness method can be used. The support precursor can be dried after impregnation, for example, preferably at a drying temperature of 50 to 150 ° C., more preferably 70 to 120 ° C., preferably 0.5 to 48 hours, more preferably 1 to 24 hours. .

The firing temperature of the carrier precursor is preferably 200 to 800 ° C, more preferably 350 to 650 ° C. The firing temperature is preferably equal to or higher than the decomposition start temperature of the zirconia compound to be used.

The unreduced catalyst includes a step of calcining a carrier precursor containing silica and a zirconia compound to obtain a carrier, and a step of calcining a catalyst precursor containing the carrier and a cobalt compound to obtain an unreduced catalyst. It may be manufactured by a manufacturing method including.

As the cobalt compound, a compound having cobalt in the molecule in the form of a salt or a complex can be used. For example, nitrate, hydrochloride, sulfate, formate, acetate, propionate, oxalate, acetylacetonate and the like can be mentioned. Specific examples include cobalt nitrate, cobalt chloride, cobalt formate, cobalt propionate, cobalt acetate, and cobalt acetylacetonate. A cobalt compound can be used individually by 1 type or in combination of 2 or more types.

As a method for preparing the catalyst precursor, an impregnation method typified by the Incipient Wetness method can be used. At this time, the content of the cobalt compound in the catalyst precursor is preferably set to be 10 to 35% by mass in terms of cobalt oxide (tricobalt tetroxide) based on the total mass of the unreduced catalyst. From the viewpoint of obtaining high reactivity, it is more preferable that the content of the cobalt compound in the catalyst precursor is 20 to 30% by mass in terms of cobalt oxide (tricobalt tetroxide) based on the total mass of the unreduced catalyst.

The catalyst precursor can be dried after impregnation, for example, preferably at a drying temperature of 50 to 150 ° C., more preferably 70 to 120 ° C., preferably 0.5 to 48 hours, more preferably 1 to 24 hours. .

The calcining temperature of the catalyst precursor is preferably 250 to 650 ° C., and more preferably 400 to 650 ° C. from the viewpoint of obtaining high dispersibility of the cobalt compound. If it exceeds 650 ° C., the form of zirconia tends to change from amorphous to crystalline, which is not preferable. The firing temperature is preferably equal to or higher than the decomposition start temperature of the cobalt compound used.

(Method for producing catalyst for FT synthesis)
The manufacturing method of the catalyst for FT synthesis which concerns on this embodiment has a reduction process which obtains the catalyst for FT synthesis by the reduction process of an unreduced catalyst.

In the reduction step, the hydrogen adsorption amount per unit mass at 100 ° C. of the catalyst for FT synthesis is 0.60 ml / g or more, and from the peak top to the peak end point of the main peak when the TPR measurement of the unreduced catalyst is performed. hydrogen consumption in the temperature range of C _1, the ratio at which the hydrogen consumption was C ₂ in the temperature range from the peak top of the main peak at the time of performing the TPR measurement of FT synthesis catalyst to a peak end point C ₂ / The unreduced catalyst is reduced so that C ₁ becomes 0.01 to 0.13.

In the reduction step, the reduction treatment may be performed so that the reduction degree of the cobalt atom represented by the formula (1) of the FT synthesis catalyst is preferably 80 to 95%, more preferably 87 to 92%. There exists a tendency for the reaction activity of the catalyst for FT synthesis to improve further by making the reduction degree of a cobalt atom 80% or more. Further, when the degree of reduction of cobalt atoms is 95% or less, excessive aggregation of cobalt metal particles is suppressed, and the reaction activity tends to be further improved.

In addition, the reduction degree of the cobalt atom in the catalyst for FT synthesis is measured as follows using a TPR (Temperature Programmed Reduction) measuring device. First, TPR measurement is performed on a non-reduced catalyst (cobalt is in an oxide state, reduction degree 0%) as a reference sample with a TPR measurement device, and the amount of m / z = 18 (H ₂ O) produced (1 ). Based on the obtained value, the “mass of all cobalt atoms” in the unreduced catalyst is determined as “cobalt atom weight × 4/3 × (generated m / z = 18 amount (1)) / molecular weight of water”. Next, the TPR measurement is performed on the measurement target catalyst using the TPR measurement device under the same conditions as the unreduced catalyst, and m / z = 18 quantity (2) is measured. Based on the obtained value, the “mass of unreduced cobalt atom” in the catalyst for FT synthesis is expressed as “cobalt atomic weight × 4/3 × (generated m / z = 18 amount (2)) / molecular weight of water”. Asking. “Mass of cobalt metal atoms” is “mass of all cobalt atoms” − “mass of unreduced cobalt atoms”. Therefore, the degree of reduction of cobalt atoms (%) = 100 × [mass of cobalt metal atoms] / [mass of all cobalt atoms] = 100 × (“mass of all cobalt atoms” − “mass of unreduced cobalt atoms”) / “Mass of all cobalt atoms” = 100 × (“generated m / z = 18 amount (1)” − “generated m / z = 18 amount (2)”) / (“generated m / z = 18 amount (1)).

In the reduction step, the reduction treatment of the unreduced catalyst may be performed by bringing a reducing gas into contact with the unreduced catalyst.

The reducing gas is a gas containing molecular hydrogen, preferably contains 70% by volume or more of molecular hydrogen, and more preferably contains 90% by volume or more of molecular hydrogen. When the molecular hydrogen content is 70% by volume or more, the reduction efficiency is improved, and the above-described effects are more remarkably exhibited. Specific gases used for the reduction treatment include hydrogen gas, a mixed gas of hydrogen gas and an inert gas such as argon gas, and the like, and hydrogen gas is particularly preferable.

In addition, when the gas used for the reduction treatment further contains carbon monoxide, an FT synthesis reaction may occur during reduction under a high pressure reduction condition of 1.1 MPa or more as an absolute pressure, which may cause problems such as heat generation. Although it is not preferable, a trace amount of contamination is acceptable.

The reduction temperature is preferably 340 to 385 ° C, more preferably 345 to 380 ° C, and further preferably 345 to 375 ° C.

The rate of temperature rise when raising the temperature to the reduction temperature is preferably less than 50 ° C./min, more preferably less than 30 ° C./min, and even more preferably less than 20 ° C./min.

In the reduction process, a predetermined holding time may be held at the reduction temperature. The holding time is preferably 4 to 20 hours. By raising the temperature to the reduction temperature at the rate of temperature rise and holding the time at the reduction temperature for the above time, a catalyst for FT synthesis satisfying the above-mentioned suitable numerical ranges of the hydrogen adsorption amount and the ratio C ₂ / C ₁ is obtained. It becomes easy to be done.

The reduction pressure is not particularly limited, but is selected from normal pressure to about 5 MPa.

The reduction treatment may be performed in a catalyst production facility, or may be performed in a facility for producing hydrocarbons by an FT synthesis method or a facility attached thereto.

Further, the reduction treatment can be carried out in a generally known reduction reaction furnace or reduction reaction tower, for example, in a fixed bed, fluidized bed, rotary kiln or the like. Preferred processes include a fluidized bed and a rotary kiln from the viewpoint of contact efficiency between the reducing gas and the catalyst.

In the reduction process, GHSV is preferably at 200h ^-1 or more, in consideration of the economic losses more preferably 200h at ^-1 to 1200 h ^-1, more preferably not more than 200h ^-1 to 1000h ^-1.

In the reduction treatment, the linear velocity is preferably less than 20 mm / s, more preferably 2 to 19 mm / s, and still more preferably 5 to 18 mm / s.

In the present specification, GHSV in the reduction treatment indicates a volume flow rate of the reducing gas per unit volume of the unreduced catalyst, and is a value obtained by, for example, “volume flow rate of reducing gas / volume of unreduced catalyst”. The linear velocity in the reduction treatment indicates the velocity of the reducing gas passing through the cross section of the reduction reaction furnace (or reduction reaction tower) filled with the unreduced catalyst. It is a value obtained by the calculation formula of “the cross-sectional area of the reduction reaction furnace (or reduction reaction tower)”.

Next, a preferred embodiment of the hydrocarbon production method of the present invention will be described below.

The hydrocarbon production method according to the present embodiment includes a step of obtaining a hydrocarbon by subjecting carbon monoxide and hydrogen gas to an FT synthesis reaction in the presence of the above-described catalyst for FT synthesis.

The raw material for carrying out the FT synthesis reaction is not particularly limited as long as it is a synthesis gas mainly composed of molecular hydrogen and carbon monoxide, but the hydrogen / carbon monoxide molar ratio is 1.5-2. A synthesis gas having a molar ratio of 1.5 to 2.2 is more preferred.

The FT synthesis reaction can be carried out in a process known as a reaction process for FT synthesis, for example, a fixed bed, a supercritical fixed bed, a slurry bed, a fluidized bed, or the like. Preferred processes include a fixed bed, a supercritical fixed bed, and a slurry bed.

There is no restriction | limiting in particular about the reaction conditions of FT synthesis reaction, It can carry out on well-known conditions. For example, the reaction temperature is 200 to 280 ° C., the gas space velocity is 1000 to 3000 h ⁻¹ , W (catalyst mass) / F (synthesis gas flow rate) is 1 to 10 g · h / mol, and the absolute pressure is 1. The reaction can be carried out in the range of 1 to 5.1 MPa.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples.

Example 1
<Preparation of unreduced catalyst>
The spherical silica particles (average particle size 67 μm, specific surface area 255 m ² / g) obtained by drying at 100 ° C. for 24 hours have a zirconium content of 5 mass% in terms of zirconium oxide based on the total mass of the unreduced catalyst. An amount of zirconylammonium carbonate was impregnated by the Incipient Wetness method. The carrier was obtained by firing the silica particles impregnated with zirconyl ammonium carbonate in air at 650 ° C. for 3 hours.

The obtained support was impregnated with an aqueous solution of cobalt nitrate in which the cobalt content based on the total mass of the unreduced catalyst was 30% by mass in terms of tricobalt tetroxide by the Incipient Wetness method. The support after impregnation with the aqueous cobalt nitrate solution was dried at 120 ° C. for 12 hours and then calcined in air at 450 ° C. for 3 hours to obtain an unreduced catalyst.

<Preparation of catalyst for FT synthesis>
The unreduced catalyst was reduced in a fixed bed reactor under a hydrogen stream. The GHSV of the hydrogen gas used for the reduction was set to 600 h ⁻¹ , the linear velocity was set to 17.6 mm / s, the catalyst layer temperature was raised from room temperature to 350 ° C. at 12.6 ° C./min, and 350 ° C. for 7 hours. This was retained to obtain a catalyst for FT synthesis.

With respect to the obtained FT synthesis catalyst, the amount of hydrogen adsorbed per unit mass at 100 ° C. was measured and found to be 0.64 ml / g. Further, the unreduced catalyst and FT synthesis catalyst obtained was subjected to TPR measurements, the ratio _C 2 / _{C 1} was 0.083. Moreover, the reduction degree of the cobalt atom in the obtained catalyst for FT synthesis was 84.9%.

<FT synthesis reaction>
2.5 g of the obtained FT synthesis catalyst was taken out in a dry box under an inert atmosphere so as not to be oxidized, and transferred to a stainless steel autoclave reactor having an internal volume of 100 cc together with 15 cc of PAO (polyalphaolefin). The raw material is a mixed gas of hydrogen gas / monoxide gas 2/1 (molar ratio), W (catalyst mass) / F (synthesis gas flow rate) = 3 g · h / mol, temperature 220 ° C., pressure 2.2 MPa. The Fischer-Tropsch synthesis reaction was started under the condition of a stirring speed of 1,000 rpm. The gas composition at the outlet of the reactor was analyzed over time by gas chromatography, and the conversion rate of carbon monoxide (CO conversion rate) was calculated from the analysis data. Table 1 shows the CO conversion after 6 hours and 48 hours from the start of the reaction.

(Examples 2 to 9)
A catalyst for FT synthesis was prepared in the same manner as in Example 1 except that the conditions for the reduction treatment were changed as shown in Table 1 or Table 2. The hydrogen adsorption amount, the ratio C ₂ / C ₁ and the degree of reduction of cobalt atoms in the obtained FT synthesis catalyst were as shown in Table 1 or Table 2, respectively. Using the obtained catalyst for FT synthesis, an FT synthesis reaction was carried out in the same manner as in Example 1, and the CO conversion rates after 6 hours and 48 hours from the start of the reaction were determined. The obtained results are shown in Tables 1 and 2.

(Examples 10 to 12)
A catalyst for FT synthesis was prepared in the same manner as in Example 1 except that the reactor was changed from a fixed bed reactor to a rotary kiln during the reduction treatment, and the reduction treatment conditions were changed as shown in Table 2. . Table 2 shows the hydrogen adsorption amount, the ratio C ₂ / C ₁ and the degree of reduction of cobalt atoms in the obtained FT synthesis catalyst. Using the obtained catalyst for FT synthesis, an FT synthesis reaction was carried out in the same manner as in Example 1, and the CO conversion rates after 6 hours and 48 hours from the start of the reaction were determined. The obtained results are shown in Table 2.

(Examples 13 to 14)
A catalyst for FT synthesis was prepared in the same manner as in Example 1 except that the conditions for the reduction treatment were changed as shown in Table 3. Table 3 shows the hydrogen adsorption amount, the ratio C ₂ / C _1, and the degree of reduction of cobalt atoms in the obtained FT synthesis catalyst. Using the obtained catalyst for FT synthesis, an FT synthesis reaction was carried out in the same manner as in Example 1, and the CO conversion rates after 6 hours and 48 hours from the start of the reaction were determined. The obtained results are shown in Table 3.

(Examples 15 to 21)
Preparation of a catalyst for FT synthesis in the same manner as in Example 1 except that the reactor was changed from a fixed bed reactor to a rotary kiln during the reduction treatment, and the reduction treatment conditions were changed as shown in Table 3 or Table 4. Went. The hydrogen adsorption amount, the ratio C ₂ / C ₁ and the degree of reduction of cobalt atoms in the obtained FT synthesis catalyst were as shown in Table 3 or Table 4, respectively. Using the obtained catalyst for FT synthesis, an FT synthesis reaction was carried out in the same manner as in Example 1, and the CO conversion rates after 6 hours and 48 hours from the start of the reaction were determined. The obtained results are shown in Table 3 or Table 4.

(Comparative Examples 1 to 6)
A catalyst for FT synthesis was prepared in the same manner as in Example 1 except that the conditions for the reduction treatment were changed as shown in Table 5. Table 5 shows the hydrogen adsorption amount, the ratio C ₂ / C ₁ and the degree of reduction of cobalt atoms in the obtained FT synthesis catalyst. Using the obtained catalyst for FT synthesis, an FT synthesis reaction was carried out in the same manner as in Example 1, and the CO conversion rates after 6 hours and 48 hours from the start of the reaction were determined. The results obtained are shown in Table 5.

Claims

Comprising a reduced product of an unreduced catalyst comprising a support containing silica and zirconium oxide and a cobalt oxide supported on the support,
The hydrogen adsorption amount per unit mass at 100 ° C. is 0.60 ml / g or more,
Main peak peak-to-peak top when the hydrogen consumption in the temperature range from a peak top to peak end point of the main peak at the time of performing the TPR measurement of the unreduced catalyst was carried out C 1, the TPR measurement of the reduced product when the hydrogen consumption in the temperature range up to the end point was set to C 2, the ratio C 2 / C 1 is 0.01 to 0.13
Fischer-Tropsch synthesis catalyst.
The Fischer-Tropsch synthesis catalyst according to claim 1, wherein the degree of reduction of the cobalt atom represented by the formula (1) is 80 to 95%.
Reduction degree of cobalt atom (%) = 100 × [mass of metallic cobalt atom] / [mass of all cobalt atoms] (1)
3. The Fischer-Tropsch synthesis catalyst according to claim 1, wherein the content of zirconium oxide in the unreduced catalyst is 0.01 to 7% by mass based on the total mass of the unreduced catalyst.
A method for producing a Fischer-Tropsch synthesis catalyst comprising:
A reduction step of obtaining the Fischer-Tropsch synthesis catalyst by reduction treatment of the unreduced catalyst,
The unreduced catalyst contains a support obtained by firing a support precursor containing silica and a zirconium compound, and a cobalt oxide supported on the support,
The hydrogen adsorption amount per unit mass at 100 ° C. of the Fischer-Tropsch synthesis catalyst is 0.60 ml / g or more;
The hydrogen consumption in the temperature range from the peak top to the peak end point of the main peak when performing the TPR measurement of the unreduced catalyst is C 1 , and the main peak when the TPR measurement of the Fischer-Tropsch synthesis catalyst is performed. when the hydrogen consumption in the temperature range from the peak top to peak endpoint was C 2, the ratio C 2 / C 1 is 0.01 to 0.13
Production method.
The production method according to claim 4, wherein the Fischer-Tropsch synthesis catalyst has a reduction degree of the cobalt atom represented by the formula (1) of 80 to 95%.
Reduction degree of cobalt atom (%) = 100 × [mass of metallic cobalt atom] / [mass of all cobalt atoms] (1)
6. The production method according to claim 4, wherein the zirconium content of the unreduced catalyst is 0.01 to 7% by mass in terms of zirconium oxide based on the total mass of the unreduced catalyst.
In the reduction step, the reducing gas is brought into contact with the unreduced catalyst, the temperature is increased to a reduction temperature of 340 to 385 ° C. at a temperature increase rate of less than 50 ° C./min, and held at the reduction temperature for 4 to 20 hours. The production method according to any one of claims 4 to 6, wherein the reduction treatment of the unreduced catalyst is performed.
The production method according to any one of claims 4 to 7, wherein in the reduction step, a reducing gas is brought into contact with the unreduced catalyst under the conditions of GHSV of 200 to 1200 h -1 and a linear velocity of less than 20 mm / s. .
A method for producing hydrocarbons, comprising the step of reacting carbon monoxide with hydrogen gas in the presence of the Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 3 to obtain hydrocarbons.
A hydrocarbon having a step of reacting carbon monoxide with hydrogen gas to obtain a hydrocarbon in the presence of the Fischer-Tropsch synthesis catalyst produced by the production method according to any one of claims 4 to 8. Manufacturing method.