JP4889307B2 - Method for producing liquid fuel using capsule catalyst - Google Patents

Description

  The present invention relates to a method for producing a liquid fuel from a synthesis gas mainly composed of hydrogen and carbon monoxide.

In recent years, the need for environmental conservation has been demanded, and the demand for clean liquid fuels with low contents of sulfur and aromatic hydrocarbons has rapidly increased. In addition, the development of energy sources that can replace oil has been desired due to the necessity of effectively using crude oil resources with limited reserves. GTL (Gas to Liquid), which uses natural gas as a raw material and produces liquid fuel that contains almost no sulfur and aromatic hydrocarbons, is gaining more and more attention. Yes.
As a method for producing liquid fuel by GTL, Fischer-Tropsch synthesis (manufactured by Fischer-Tropsch synthesis, which produces high-grade paraffin using synthetic gas consisting of hydrogen and carbon monoxide as a raw material after a reforming process for producing hydrogen and carbon monoxide from natural gas Hereinafter, it is generally known a process in which the process is performed in two stages, a process of performing FT synthesis), and a process of hydrocracking and isomerization in which an FT synthesis product rich in higher paraffin is converted into a product rich in lower paraffin. It has been.

In general, FT synthesis is carried out using a catalyst obtained by supporting an active metal such as iron or cobalt on a carrier such as silica or alumina (hereinafter referred to as FT synthesis catalyst). In addition, a method in which the hydrocracking / isomerization reaction is performed using a zeolite or an amorphous solid acid catalyst is generally known.
On the other hand, Non-Patent Document 1 shows that lower paraffin is produced from synthesis gas in one stage by using a catalyst obtained by physically mixing a FT synthesis catalyst and a solid acid catalyst such as zeolite.
In Non-Patent Document 2, a capsule catalyst in which the outer surface of a particulate FT synthesis catalyst is coated with a ZSM-5 film is prepared, and liquid fuel is produced in one step from synthesis gas using the capsule catalyst. The reaction is shown.
Fujimoto et al., “Chemistry Letters”, 1985, p783. "Abstracts of the 54th Annual Meeting of the Petroleum Society of Japan", Petroleum Society, May 16, 2005, 102

The process in which the FT synthesis and the hydrocracking / isomerization reaction are performed in one stage can be said to be an economical process with a low construction cost of the apparatus as compared with the case of performing the reactions separately. In this one-stage reaction process, a method for producing a liquid fuel using a capsule catalyst having a ZSM-5 membrane has been reported. However, a method for producing a liquid fuel having a higher performance than this method, that is, by-product methane and There is still no method for producing a liquid fuel with a low CO ₂ selectivity and a high ratio of isoparaffin and olefin. In order to further improve the economics of this one-stage reaction process, it is necessary to further reduce the methane and CO ₂ selectivity. Further, in order to use the produced oil as a gasoline base, it is necessary to further increase the yield of isoparaffin and olefin.
An object of the present invention is to provide a method for producing a liquid fuel by a one-stage reaction process in which methane and CO ₂ selectivity is reduced and isoparaffin and olefin selectivity are improved.

As a result of intensive studies, the present inventors have succeeded in preparing a capsule catalyst in which the surface of an FT synthesis catalyst is coated with beta zeolite, and by using such a capsule catalyst as a catalyst for a one-step reaction, methane selectivity and CO _{2 are obtained.} The inventors have found that the selectivity can be reduced and the isoparaffin yield and olefin yield of the product oil can be increased, and the above-described problems have been solved.
That is, the present invention relates to a method for producing a liquid fuel, characterized in that a synthesis gas containing hydrogen and carbon monoxide is converted in the presence of a particulate solid catalyst coated with beta zeolite.

According to the method of the present invention, it is possible to obtain a liquid fuel with reduced methane selectivity and CO ₂ selectivity and increased isoparaffin and olefin yields in a one-stage reaction process from synthesis gas.

The present invention is described in detail below.
The catalyst used in the method for producing a liquid fuel of the present invention is a particulate solid catalyst in which a beta zeolite film is formed on the surface of the particulate solid.

The particulate solid is mainly composed of an inorganic oxide.
As an inorganic oxide constituting the particulate solid, silica, alumina, titania, silica alumina and the like can be given as preferable examples. Of these, alumina is particularly preferred.
Although there is no restriction | limiting in particular about the average particle diameter of the inorganic oxide to be used, Usually, 10 micrometers-10 mm, Preferably 50 micrometers-5 mm thing is suitably selected and used according to a process. Although there is no special restriction on the specific surface area of the inorganic oxide used, usually 100 to 400 m ² / g, preferably it is used as the 200 to 300 m ² / g.

As the particulate solid, a material in which a metal is supported on the inorganic oxide is preferably used. As the metal to be supported, Co metal is particularly preferable. Although there is no restriction | limiting in particular in the carrying amount, 1-50 mass% per metal is preferable with respect to an inorganic oxide support | carrier, More preferably, it is 5-30 mass%.
In the present invention, if necessary, one or more metals selected from Ru, Zr, Re and Os can be further supported as a promoter. Although the amount of these promoters supported is not particularly limited, it can be generally used in the range of 1 to 20% by mass as the amount of metal per particulate solid.

Beta zeolite is capped on such a particulate solid surface.
The amount of beta zeolite covered on the surface of the particulate solid is not particularly limited, but is preferably in the range of 5 to 40 mass%, more preferably 10 to 30 mass% with respect to the particulate solid.

Examples of the method for forming the beta zeolite membrane on the surface of the particulate solid include the following methods.
First, the particulate solid is refluxed in an aqueous solution containing a template used in the hydrothermal synthesis reaction of beta zeolite. As the template, usually tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or the like can be used. The reflux treatment time is not particularly limited but is preferably 2 to 5 hours. If necessary, the particulate solid after reflux is washed with water and / or alcohol.

  The particulate solid after the pretreatment by the above reflux treatment is put into a reactor together with a precursor solution of beta zeolite, and a hydrothermal synthesis reaction is performed. The conditions for the hydrothermal synthesis reaction are not particularly limited and can be performed under ordinary conditions. For example, the reaction temperature is 100 to 200 ° C., preferably 130 to 180 ° C., and the reaction time is 1 to 10 days, preferably 1 to 5 days.

In addition, the hydrothermal synthesis reaction is performed under stirring, but is not performed continuously at a constant speed, but is performed repeatedly by stirring and stopping. The stirring speed is preferably 1 to 20 rpm, more preferably 1 to 10 rpm. In this case, the number of stirring and stopping is preferably repeated at least 2 times, more preferably 5 times or more, and even more preferably 10 times or more, and is appropriately determined in consideration of effects, economy, and the like. . Specifically, the reaction is first carried out with stirring for 1 to 20 hours, preferably 1 to 5 hours, and then the reaction is stopped. The stop time is preferably 30 minutes to 10 hours, more preferably 30 minutes to 5 hours. Then stir again. The stirring time after the second time is 1 to 30 minutes, preferably 1 to 10 minutes.
By such treatment, a catalyst having a beta zeolite film formed on the surface of the particulate solid is obtained.

  In the present invention, if necessary, a metal selected from the group consisting of Pt, Pd, and combinations thereof can be supported on beta zeolite. Although there is no restriction | limiting in particular about the load of these metals, Usually, it can use in 0.1-5 mass% as metal amount per particulate solid.

In the present invention, a liquid fuel is produced by converting a synthesis gas containing hydrogen and carbon monoxide in the presence of the particulate solid catalyst coated with the aforementioned beta zeolite.
The hydrogen / carbon monoxide ratio in the synthesis gas used in the present invention is preferably 0.5 to 5, and more preferably 0.5 to 2.

The conversion reaction in the present invention employs a one-stage reaction process. As the one-stage reaction process, a fixed bed reactor or a slurry bed reactor can be usually used.
The conversion reaction of the present invention, it is preferable that GHSV of the synthesis gas is 500～5000H ^-1, more preferably carried out in 800~2000h ^-1.
Moreover, it is preferable that the reaction temperature in the conversion reaction in this invention is 100-400 degreeC, More preferably, it is 200-300 degreeC, It is preferable that reaction pressure is 0.1-10 MPa, More preferably, it is 0.3. It is carried out at ˜5 MPa.

As described above, according to the method of the present invention, a liquid fuel with reduced methane selectivity and CO ₂ selectivity and increased isoparaffin and olefin yield is obtained from a synthesis gas containing hydrogen and carbon monoxide in a one-stage reaction process. be able to.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these.

[Preparation Example 1 (Preparation of Catalyst 1)]
(1) Co supported _Al 2 _{O 3} of Preparation 2.7g of Co _{(NO 3)} 2 · 6H the ₂ O to prepare an aqueous solution prepared by dissolving in deionized water 4.7 g, 2 hours dry _Al 2 O at 400 ° C. ₃ (particle diameter 10-20 mesh, specific surface area 180 m ² / g, pore volume 0.93 ml / g) was impregnated by the Incipient Wetness method. Then, after placing in a desiccator and depressurizing with a water pump for 1 hour, it was dried at 120 ° C. for 12 hours. Thereafter, the temperature was raised from 20 ° C. to 400 ° C. over 3 hours in a muffle furnace, and the mixture was held at 400 ° C. for 2 hours and fired to prepare 10 mass% Co-supported Al ₂ O ₃ .

(2) Preparation of Precursor Solution 4.1 g of SiO ₂ (fumed Silica, specific surface area 200 m ² / g) was dissolved in 10.3 g of tetraethylammonium hydroxide (TEAOH) and stirred for 1 hour to be uniform. Made colloidal.
0.3 g of ((CH ₃ ) ₂ CHO) ₃ Al (Aluminium triisopropoxide) was dissolved in 4.1 g of TEAOH and added dropwise to the SiO ₂ / TEAOH solution over 15 minutes. Thereafter, 3.6 g of ion-exchanged water was added and stirred at room temperature for 2 hours to prepare a precursor solution.

(3) Co supported _Al 2 _{O 3} of preprocessing the 104 ° C. at 25 wt% TEAOH aqueous solution 5g of Co supported _Al 2 _O 3 1 g prepared in, and refluxed for 4 hours.
After completion of the reflux treatment, it was washed 3 times with ion exchange water and then immersed in ethanol for 1 day.

(4) Hydrothermal synthesis reaction Co-supported Al ₂ O ₃ that had been pretreated was blotted of ethanol on the surface with filter paper, and then placed in a hydrothermal synthesis reaction reactor. The prepared precursor solution was also put into the reactor and subjected to a hydrothermal synthesis reaction at 155 ° C. for 3 days.
The rotation was initially rotated at 2 rpm for 5 hours, and thereafter, the operation of stopping for 1 hour and then rotating at 2 rpm for 2 minutes was repeated 60 times. After completion of the hydrothermal synthesis reaction, the reaction product was taken out of the reactor and washed with ion-exchanged water until the pH of the washing solution became 8 or less. After washing, it was dried at 120 ° C. for 12 hours, and then heated from 20 ° C. to 550 ° C. over 8 hours in a muffle furnace, held at 550 ° C. for 5 hours, and fired.
A particulate solid catalyst (catalyst 1) having a beta zeolite film was prepared by the above steps.

[Preparation Example 2 (Preparation of Catalyst 2)]
10 mass% Co-supported SiO ₂ (Q-10) prepared by the same method as 10 mass% Co-supported Al ₂ O _{3 in} Preparation Example 1 was converted into SiO ₂ / tetrapropylammonium hydroxide / H ₂ O / Al ₂ O. ₃ = 1 / 0.25 / 60/4 / 0.0125 (molar ratio) of the precursor solution is used to carry out a hydrothermal synthesis reaction at 180 ° C. for 2 days in an autoclave to have a ZSM-5 film. A particulate solid catalyst (Catalyst 2) was prepared.

[Preparation Example 3 (Preparation of Catalyst 3)]
The catalyst 3 was prepared by physically mixing 10% by mass Co-supported Al ₂ O ₃ in Preparation Example 1 with 20% by mass of beta zeolite.

[Preparation Example 4 (Preparation of Catalyst 4)]
10% by mass Co-supported Al ₂ O ₃ in Preparation Example 1 was used as it was as a catalyst (catalyst 4).

[Examples 1 and 2 and Comparative Examples 1 to 3]
The catalysts 1 to 4 obtained above were reduced at 400 ° C. for 10 hours under a hydrogen flow, and then a synthesis gas was passed to obtain 533 K, 1.0 MPa, W / F = 10 gcat. The conversion reaction was performed under h / mol conditions. (Example 1, Comparative Examples 1-3). Catalyst 1 has W / F = 5 gcat. Evaluation was also performed with h / mol (Example 2). The results of the reaction are shown in Table 1. _C iso / _{C n} in Table 1, the product shows a ratio of isoparaffin / normal paraffins (having 4 or more carbon atoms) in ^the ratio of olefin / paraffin C = / _{C n} the product (2 or more carbon atoms) Indicates.
As shown in Table 1, by coating with beta zeolite, methane selectivity and CO ₂ selectivity can be suppressed, and the isoparaffin yield and olefin yield of the product oil can be improved.

Claims (11)

Liquid fuel, wherein a synthesis gas containing hydrogen and carbon monoxide, is converted in the presence of a Fischer-Tropsch synthesis catalyst is a particulate solid surface to beta zeolite film formed particulate solids catalyst of Manufacturing method.   The process according to claim 1, wherein the reaction temperature is 100 to 400 ° C. The production method according to claim 1 or 2, wherein the synthesis gas has a GHSV of 500 to 5000 h- ¹ .   The method according to claim 1, wherein the ratio of hydrogen / carbon monoxide in the synthesis gas is 0.5-5.   The reaction pressure is 0.1-10 MPa, The manufacturing method in any one of Claims 1-4 characterized by the above-mentioned.   6. The production method according to claim 1, wherein the particulate solid is made of an inorganic oxide mainly composed of alumina.   The manufacturing method according to claim 1, wherein the particulate solid contains Co.   The manufacturing method according to claim 7, wherein the particulate solid further contains a metal selected from the group consisting of Ru, Zr, Re, Os and combinations thereof.   The production method according to any one of claims 1 to 8, wherein a metal selected from the group consisting of Pt, Pd and a combination thereof is supported on beta zeolite. The particulate solid catalyst on which the beta zeolite film is formed treats the surface of the Fischer-Tropsch synthesized catalyst particles with a template used during the hydrothermal synthesis reaction of the beta zeolite, and the surface-treated Fischer-Tropsch synthesized catalyst particles The method for producing a liquid fuel according to any one of claims 1 to 9, which is obtained by performing a hydrothermal synthesis reaction of beta zeolite in the presence. The method for producing a liquid fuel according to claim 10, wherein the hydrothermal synthesis reaction is performed by repeatedly stirring and stopping.