JP2008133369A - Method for producing liquid fuel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a liquid fuel, capable of achieving a high level of intermediate fraction selectivity in producing the liquid fuel from a paraffin-based hydrocarbon. <P>SOLUTION: This method for producing the liquid fuel comprises a first process of performing the hydroisomerization treatment of the paraffin-based hydrocarbon by using a prescribed catalyst, and a second process of performing the hydrocracking treatment on the treated material obtained in the first process by using a catalyst containing a crystalline alminosilicate having ≥50 molar ratio of silica/alumina. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a liquid fuel from paraffinic hydrocarbons in the presence of hydrogen.

  In recent years, there has been a rapid increase in demand for clean liquid fuels with low sulfur and aromatic hydrocarbon content. In response to this, various clean fuel production methods have already been studied in the fuel oil production industry. Among them, the method (hydroisomerization cracking) in which paraffinic hydrocarbons such as wax are isomerized and decomposed in the presence of hydrogen using a catalyst is considered to be most effective.

Conventional hydroisomerization cracking is a process in which paraffinic hydrocarbons are directly introduced into a reaction tower and treated with a catalyst in the presence of hydrogen (see, for example, Non-Patent Document 1 and Patent Document 1). In such a process, research and development have been vigorously conducted so that high middle distillate selectivity can be obtained by improving the catalyst (see, for example, Patent Document 2).
The Japan Petroleum Institute “Petroleum Refining Process”, 1998, p. 231 JP 59-105081 A JP-A-6-41549

  In the hydroisomerization of paraffinic hydrocarbons, obtaining a useful middle distillate in a high yield is important for improving the economics of the process. However, in spite of many years of research and development focusing on catalysts, a satisfactory hydroisomerization process with high middle distillate selectivity has not yet been established. This is a major obstacle to full-scale practical application of clean liquid fuel.

  The present invention has been made in view of such a situation, and an object thereof is a liquid fuel capable of achieving a high middle distillate selectivity when producing a liquid fuel from paraffinic hydrocarbons. It is in providing the manufacturing method of.

  In order to solve the above-mentioned problems, the present invention provides a first step of hydroisomerizing a paraffinic hydrocarbon using a predetermined catalyst, and an object to be obtained obtained in the first step. And a second step of hydrocracking using a catalyst containing a crystalline aluminosilicate having a silica / alumina ratio of 50 or more.

  Here, the “hydroisomerization treatment” as used in the present invention is a hydrogenation treatment that does not substantially involve hydrocracking, that is, without a substantial decrease in molecular weight (usually the average molecular weight is an indicator). In other words, it means a hydrogenation treatment in which an object to be treated is converted into another compound. On the other hand, the “hydrocracking treatment” in the present invention means a hydrotreating accompanied by a decrease in the molecular weight of the object to be treated. In the hydrocracking treatment, hydroisomerization can occur simultaneously. That is, when the hydroisomerization treatment is performed on the paraffinic hydrocarbon, the degree of branching of the hydrocarbon is increased by the action of the catalyst in the presence of hydrogen while the carbon number of the molecule is substantially maintained. Further, when hydrocracking treatment is performed on paraffinic hydrocarbons, hydrocarbons having a boiling point lower than that of the raw material hydrocarbons are generated by the action of the catalyst in the presence of hydrogen. In the conventional hydroisomerization process of paraffinic hydrocarbons, both the hydrocracking and hydroisomerization reactions proceed in a complicated manner in the same reaction vessel in the presence of a catalyst.

  According to the method for producing a liquid fuel of the present invention, a hydroisomerization step (first step) substantially not involving hydrocracking is provided before the hydrocracking treatment step (second step), In addition, by using a crystalline aluminosilicate catalyst having a silica / alumina ratio of 50 or more in molar ratio in the hydrocracking process (second process) as the latter stage, a high level of middle distillate selectivity is achieved. Is possible. The above-described effects of the present invention are novel results that cannot be obtained by the conventional method of directly treating paraffinic hydrocarbons by hydroisomerization, and are completely unexpected in view of the conventional technical level. It can be said. The “middle fraction” in the present invention means a fraction having a boiling point of 145 to 360 ° C.

  As described above, the hydroisomerization treatment according to the present invention is a hydrogenation treatment that does not substantially involve hydrocracking, but the hydrocracking rate in the hydroisomerization treatment is less than 10.0%. Preferably, it is less than 5.0%, more preferably less than 3.0%. As used herein, “hydrocracking rate” means the mass ratio of hydrocracked product to raw material paraffinic hydrocarbon, and “hydrocracked product” means a fraction having a boiling point of 360 ° C. or lower. Means.

  In the present invention, the crystalline aluminosilicate contained in the catalyst used in the second step is preferably an ultra-stabilized Y-type zeolite.

  The silica / alumina ratio of the crystalline aluminosilicate contained in the catalyst used in the second step is preferably 80 or more in terms of molar ratio.

  Moreover, it is preferable that the catalyst used in the first step and the second step each contains platinum.

  In the present invention, the paraffinic hydrocarbon used as a raw material is preferably produced by a hydrogenation reaction of carbon monoxide.

  As described above, according to the method for producing a liquid fuel of the present invention, a high level of middle distillate selectivity can be achieved when producing a liquid fuel from paraffinic hydrocarbons.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The paraffinic hydrocarbon in the present invention refers to a hydrocarbon mixture containing normal paraffin as a main component and a content of 60% by mass or more. The carbon number of the paraffinic hydrocarbon is not particularly limited, but is usually about 20 to 100. The paraffinic hydrocarbon production method of the present invention is not particularly limited, and the present invention can be applied to various petroleum and synthetic paraffinic hydrocarbons. As a particularly preferable paraffinic hydrocarbon, a reduction reaction of carbon monoxide is performed. The so-called FT wax produced by the used Fischer-Tropsch synthesis (FT synthesis) can be mentioned.

  In the present invention, the above-mentioned paraffinic hydrocarbon is first subjected to hydroisomerization treatment using a predetermined catalyst (first step), thereby focusing on the conversion from normal paraffin to isoparaffin. The isomerization reaction proceeds.

  The hydrocracking rate in the hydroisomerization treatment is preferably less than 10.0%, more preferably less than 5.0%, and still more preferably less than 3.0%. As a method of setting the hydrocracking rate in the hydroisomerization treatment to less than 10.0%, for example, a method of controlling the reaction temperature and reaction pressure is effective.

  Although there is no restriction | limiting in particular in the kind of catalyst used at the hydroisomerization process based on this invention, Usually, the catalyst which carry | supported the metal on the support | carrier containing a solid acid is used. Preferred examples of the solid acid include silica alumina, alumina boria, silica zirconia, and silica titania, and particularly preferred examples of the solid acid include silica alumina, alumina boria, and silica zirconia.

  The above solid acid can be used as a carrier without using a binder, but it can usually be used as a carrier molded with a binder. The binder used in that case is not particularly limited, but alumina and silica can be used, and most preferably alumina. Although the usage-amount of a binder is not restrict | limited in particular, Preferably it is 20-90 mass% on the basis of the total mass of a support | carrier, More preferably, it is 40-80 mass%. By making the usage-amount of a binder into the range of 20-90 mass%, the catalyst which has sufficient intensity | strength can be obtained effectively.

  Further, the catalyst used in the hydroisomerization process according to the present invention preferably contains a metal of Group VI b and / or a Group VIII metal of the Periodic Table. The metal is usually supported on a carrier containing the above solid acid. Specific examples of the Group VIb metal include chromium, molybdenum, and tungsten, and specific examples of the Group VIII metal include cobalt, nickel, rhodium, palladium, iridium, and platinum. . Among these, palladium and platinum are preferable, and platinum is particularly preferable. The amount of metal supported is not particularly limited, but in the case of palladium and platinum, it is preferably 0.05 to 2% by mass with respect to the support.

The hydroisomerization process according to the present invention can be performed using a conventional fixed bed reactor. Typical processing conditions include a temperature of 200 to 370 ° C., a hydrogen pressure of 0.5 to 10 MPa, and a liquid space velocity of the paraffinic hydrocarbon raw material of 0.1 to 5.0 h ⁻¹ .

  Next, a hydrocracking process is performed about the to-be-processed object obtained by a hydroisomerization process process (2nd process).

  The catalyst used in the hydrocracking treatment step contains a crystalline aluminosilicate having a silica / alumina ratio of 50 or more, preferably 60 to 100 in molar ratio. When the silica / alumina ratio is less than 50, middle distillate selectivity is insufficient. On the other hand, when the silica / alumina ratio exceeds 100, the reaction temperature becomes high and the catalyst tends to deteriorate.

  The type of crystalline aluminosilicate contained in the catalyst used in the hydrocracking treatment step is not particularly limited as long as the silica / alumina ratio is 50 or more in molar ratio, but preferably USY zeolite or mordenite zeolite. Β-type zeolite, particularly preferably USY zeolite.

  Although the above crystalline aluminosilicate can be used as a carrier without using a binder, it can usually be used as a carrier molded with a binder. The binder used in that case is not particularly limited, but alumina and silica can be used, and most preferably alumina. Although the usage-amount of a binder is not specifically limited, Preferably it is 50-99 mass% on the basis of the total mass of a support | carrier, More preferably, it is 80-97 mass%. By making the usage-amount of a binder into the range of 50-99 mass%, the catalyst which has sufficient intensity | strength can be obtained effectively.

  The catalyst used in the hydroisomerization treatment step preferably contains a metal of group VI b and / or a metal of group VIII of the periodic table. The metal is usually supported on a carrier containing the crystalline aluminosilicate. Specific examples of the Group VIb metal include chromium, molybdenum, and tungsten, and specific examples of the Group VIII metal include cobalt, nickel, rhodium, palladium, iridium, and platinum. . Among these, palladium and platinum are preferable, and platinum is particularly preferable. The amount of metal supported is not particularly limited, but in the case of palladium and platinum, it is usually 0.05 to 2% by mass with respect to the support.

  The hydrocracking process can be performed using a conventional fixed bed reactor. Typical reaction conditions include a temperature of 250 to 370 ° C., a hydrogen pressure of 0.5 to 10 MPa, and a liquid space velocity of the paraffinic hydrocarbon raw material of 0.1 to 5.0 / h.

  Thus, the hydrocracking process (first process) that does not substantially involve hydrocracking is provided in the preceding stage of the hydrocracking process process (second process), and the hydrocracking process that is the latter stage. By using a crystalline aluminosilicate catalyst having a silica / alumina ratio of 50 or more in molar ratio in the step (second step), it is possible to achieve a high level of middle distillate selectivity.

  In addition, in the to-be-processed object (hydrocracking product) after a hydrocracking process process, in addition to a middle fraction, a light fraction (both naphtha fraction, etc.) having a boiling point of less than 145 ° C., a boiling point exceeding 360 ° C. A wax fraction and the like are included, but by providing a distillation step after the hydrocracking treatment step, these fractions can be separated according to the distillation properties. Further, for example, the middle distillate may include a kerosene distillate (a distillate having a boiling point of 145 to 260 ° C.), a light oil distillate (a distillate having a boiling point of 260 to 360 ° C.), etc., but these can also be separated in the distillation step. .

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Preparation of catalyst]
(Catalyst 1)
A mixture consisting of 60% by mass of amorphous silica alumina having an alumina content of 13%, a pore volume of 0.65 ml / g, and an average particle size of 6 μm and 40% by mass of boehmite as a binder was sufficiently kneaded. The catalyst carrier was obtained by molding into a 16-inch (about 1.6 mm) cylindrical shape and firing the resulting molded body at 500 ° C. for 1 hour. This support was impregnated with an aqueous solution of dichlorotetraammineplatinum (II) in an amount of 0.5% by mass of the support as platinum, dried at 120 ° C. for 3 hours, and then calcined at 500 ° C. for 1 hour, whereby catalyst 1 was obtained. Prepared.

(Catalyst 2)
A mixture of 60% by mass of amorphous silica zirconia having a zirconia content of 40%, a pore volume of 0.72 ml / g and an average particle size of 8 μm and 40% by mass of boehmite as a binder was sufficiently kneaded. The catalyst carrier was obtained by molding into a cylindrical shape of inches (about 1.6 mm) and firing the resulting molded body at 500 ° C. for 1 hour. The carrier was impregnated with an aqueous solution of dichlorotetraammineplatinum (II) in an amount of 0.5% by mass of the carrier as platinum, dried at 120 ° C. for 3 hours, and then calcined at 500 ° C. for 1 hour, whereby catalyst 2 was obtained. Prepared.

(Catalyst 3)
A mixture of 3% by mass of USY zeolite having a silica / alumina molar ratio of 58 and 97% by mass of boehmite as a binder was sufficiently kneaded, and the kneaded product was a circle having a diameter of 1/16 inch (about 1.6 mm). The catalyst carrier was obtained by molding into a column and firing the resulting molded body at 500 ° C. for 1 hour. This support was impregnated with an aqueous solution of dichlorotetraammineplatinum (II) in an amount of 0.8% by mass of the support as platinum, dried at 120 ° C. for 3 hours, and then calcined at 500 ° C. for 1 hour, whereby catalyst 3 was obtained. Prepared.

(Catalyst 4)
A mixture of 3% by mass of USY zeolite having a silica / alumina molar ratio of 95 and 97% by mass of boehmite as a binder was sufficiently kneaded, and the kneaded product was a circle having a diameter of 1/16 inch (about 1.6 mm). The catalyst carrier was obtained by molding into a column and firing the resulting molded body at 500 ° C. for 1 hour. This support was impregnated with an aqueous solution of dichlorotetraammineplatinum (II) in an amount of 0.8% by mass of the support as platinum, dried at 120 ° C. for 3 hours, and then calcined at 500 ° C. for 1 hour, whereby catalyst 4 was obtained. Prepared.

(Catalyst 5)
A mixture of 3% by mass of USY zeolite having a silica / alumina molar ratio of 30 and 97% by mass of boehmite as a binder was sufficiently kneaded, and the kneaded material was a 1/16 inch (about 1.6 mm) diameter circle. The catalyst carrier was obtained by molding into a column and firing the resulting molded body at 500 ° C. for 1 hour. This support was impregnated with an aqueous solution of dichlorotetraammineplatinum (II) in an amount of 0.8% by mass of the support as platinum, dried at 120 ° C. for 3 hours, and then calcined at 500 ° C. for 1 hour, whereby catalyst 5 was obtained. Prepared.

[Example 1]
First, an FT wax having a carbon number of 21 to 80 (boiling point of 360 ° C. or higher) is supplied to a fixed bed flow reactor filled with the catalyst 1, and the temperature is 310 ° C., the hydrogen pressure is 3 MPa, the liquid space velocity of the raw material is 2 Hydroisomerization was performed under the condition of 0.0 h- ¹ . As a result of performing distillation gas chromatography measurement on the product to be treated (hereinafter referred to as “product oil A”), the hydrocracking rate (hydrocracking product relative to the raw material (the fraction having a boiling point of 360 ° C. or lower)) (Mass ratio) was 1.2%.

  Next, the product oil A was supplied to a fixed bed flow reactor filled with the catalyst 3 and subjected to hydrocracking under conditions of a hydrogen pressure of 3 MPa and a raw material liquid space velocity of 2.0 / h. . In the present example, the hydrocracking rate (mass ratio of hydrocracking product (boiling fraction having a boiling point of 360 ° C. or lower)) to the material to be treated before hydrocracking treatment was 80% at a reaction temperature of 316 ° C. . Moreover, the ratio of the middle fraction (fraction having a boiling point of 145 to 360 ° C.) in the hydrocracking product (hereinafter referred to as “middle fraction selectivity”) was 80.1%.

[Example 2]
First, hydroisomerization was performed in the same manner as in Example 1 to obtain product oil A.

  Next, hydrocracking treatment was performed in the same manner as in Example 1 except that the catalyst 4 was used instead of the catalyst 3 and the reaction temperature was changed from 316 ° C. to 337 ° C. The hydrocracking rate and middle distillate selectivity at this time are shown in Table 1.

[Example 3]
First, an FT wax having a carbon number of 21 to 80 (boiling point of 360 ° C. or higher) is supplied to a fixed bed flow reactor filled with the catalyst 2, and the temperature is 320 ° C., the hydrogen pressure is 4 MPa, the liquid space velocity of the raw material is 2 Hydroisomerization was performed under the condition of 0.0 h- ¹ . As a result of performing distillation gas chromatography measurement on the obtained material to be treated (hereinafter referred to as “product oil B”), the hydrocracking rate (hydrocracking product relative to the raw material (fraction having a boiling point of 360 ° C. or lower)) was measured. (Mass ratio) was 0.8%.

  Next, hydrocracking treatment was performed in the same manner as in Example 1 except that the product oil B was used instead of the product oil A, and the reaction temperature was changed from 316 ° C. to 317 ° C. The hydrocracking rate and middle distillate selectivity at this time are shown in Table 1.

[Comparative Example 1]
First, hydroisomerization was performed in the same manner as in Example 1 except that the temperature was changed from 310 ° C to 325 ° C. The obtained material to be treated (hereinafter referred to as “product oil C”) was subjected to distillation gas chromatography measurement. As a result, the hydrocracking rate was 14.8%.

  Next, hydrocracking treatment was performed in the same manner as in the example except that the product oil B was used instead of the product oil A and the reaction temperature was changed from 316 ° C. to 312 ° C. The hydrocracking rate and middle distillate selectivity at this time are shown in Table 1.

[Comparative Example 2]
First, hydroisomerization was performed in the same manner as in Example 1 to obtain product oil A.

  Next, hydrocracking treatment was performed in the same manner as in Example 1 except that the catalyst 5 was used instead of the catalyst 3 and the reaction temperature was changed from 316 ° C. to 308 ° C. The hydrocracking rate and middle distillate selectivity at this time are shown in Table 1.

[Comparative Example 3]
First, hydroisomerization was performed in the same manner as in Example 3 to obtain product oil B.

    Next, hydrocracking treatment was performed in the same manner as in Example 3 except that the catalyst 5 was used instead of the catalyst 3 and the reaction temperature was changed from 317 ° C. to 302 ° C. The hydrocracking rate and middle distillate selectivity at this time are shown in Table 1.

Claims (5)

For paraffinic hydrocarbons, a first step of performing hydroisomerization using a predetermined catalyst;
The object to be treated obtained in the first step includes a second step of performing a hydrocracking treatment using a catalyst containing crystalline aluminosilicate having a silica / alumina ratio of 50 or more in molar ratio. A method for producing a liquid fuel.   2. The method for producing a liquid fuel according to claim 1, wherein the crystalline aluminosilicate is an ultra-stabilized Y-type zeolite.   The method for producing a liquid fuel according to claim 1 or 2, wherein the crystalline aluminosilicate has a silica / alumina ratio of 80 or more in terms of a molar ratio.   The method for producing a liquid fuel according to any one of claims 1 to 3, wherein the catalyst used in the first step and the second step each contains platinum. The method for producing a liquid fuel according to any one of claims 1 to 4, wherein the paraffinic hydrocarbon is produced by a hydrogenation reaction of carbon monoxide.