JPH067925B2 - Hydrocracking catalyst for middle distillate production - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention is applied to the catalytic conversion technology of hydrocarbons. This invention relates to new catalysts for use in hydrocracking processes. More specifically, the present invention exhibits excellent activity, selectivity and durability against deactivation when used in a hydrocracking process for producing middle distillates from heavy gas oils, etc. under hydrocracking conditions. It relates to a hydrocracking catalyst.

Many refineries today hydrocrack feedstocks such as heavy gas oils to produce middle distillate products such as jet fuels and diesel fuels. This feedstock is usually about
Boiling points range from 650 to 1050 ° F (343 to 566 ° C). The hydrocracking product can be obtained by contacting a heavy oil with a suitable hydrocracking catalyst under conditions of elevated temperature and pressure and in the presence of hydrogen. The middle distillate product thus obtained has a boiling point in the range of about 300-700 ° F (149-371 ° C). The interest of today's refineries is to increase the yield of middle distillate products by hydrocracking. The yield of middle distillate products can be increased by improving the performance of the catalyst used in hydrocracking.

Activity, selectivity and stability are the three major catalytic performances in evaluating hydrocracking catalysts. For the catalytic activity, the same feedstock is used, and other hydrocracking conditions are kept constant,
It is evaluated by contrasting the temperatures required to keep the conversion to a product with a particular boiling point constant. The lower this temperature is for a catalyst, the more active it is. The selectivity of the hydrocracking catalyst is evaluated by the yield of desired product. Stability is evaluated by how long a catalyst can maintain its activity and selectivity when treating a given hydrocarbon feedstock. Stability is generally measured by the amount of change in temperature required per day to maintain a given conversion.

The ultimate goal of hydrocracking catalysts is to provide the catalyst with the highest possible activity, selectivity and stability. The catalyst used in the hydrocracking process usually contains a Group VIII metal component and a Group VIB metal component (eg, chromium, molybdenum and tungsten), which metal component is in intimate admixture with the support material. . The activity, selectivity and stability of the catalyst vary significantly with different supports. Carrier materials known in the hydrocracking technology include amorphous silica alumina, heat resistant porous inorganic oxides such as alumina,
Crystalline aluminosilicate zeolites such as Zeolite-Y are included. In general, support materials composed of refractory oxides have relatively low activity but high selectivity, while support materials composed of zeolites usually have high activity but low selectivity.

Therefore, the present invention provides a hydrocracking catalyst having excellent catalytic performance for hydrocracking of hydrocarbons. That is, an object of the present invention is to provide a hydrocracking catalyst having excellent activity, selectivity and stability as compared with conventional catalysts. Further, it is an object of the present invention to provide a hydrocracking catalyst which exhibits excellent catalytic performance in converting heavy gas oil into a middle distillate product.
Furthermore, it is an object of the present invention to provide a carrier material useful in hydrocracking processes. It is also an object of the invention to provide a hydrocracking process suitable for converting heavy gas oils to middle distillate products. Other objects and advantages of the present invention will be apparent from the description below.

Background of the Invention Decomposition catalysts in which zeolites are dispersed in an inorganic oxide matrix are described in numerous patents.

U.S. Pat. No. 4,419,721 discloses a hydrocracking catalyst used to produce middle distillates containing a crystalline aluminosilicate zeolite on a support having silica-alumina dispersed in an aluminum matrix. A catalyst carrying a hydrogenation component is described. This patent teaches that one or more crystalline aluminosilicates having degrading activity can be dispersed in a double matrix, but does not disclose a specific mixture of zeolites.

U.S. Pat. No. 4,287,048 describes a hydrocracking catalyst in which ultrastable Y-type zeolite and a small pore crystalline zeolite such as mordenite are dispersed in an inorganic oxide matrix.

U.S. Pat. No. 4,137,152 describes a cracking process utilizing a mixture of faujasite and mordenite.

U.S. Pat. No. 3,894,934 describes the catalytic cracking of hydrocarbons utilizing a large pore zeolite dispersed in a conventional matrix and a small pore zeolite such as Zeolite-ZSM-5.

U.S. Pat. No. 3,804,747 describes a hydrocarbon conversion process that utilizes a mixture of zeolites X and Y.

U.S. Pat. No. 3,758,403 describes a catalytic cracking composition in which a large pore zeolite such as zeolite Y and a small pore zeolite such as ZSM-5 are dispersed in a silica based matrix. This matrix may be active, such as silica-alumina or alumina, but may be inactive. The use of zeolites such as ZSM-5 gives high octane fuels.

U.S. Pat. No. 3,769,202 describes a catalyst containing two types of zeolites, one of which has a pore size of greater than 8 angstroms and the other having a pore size of less than 7 angstroms. These zeolites are mixed with an inorganic oxide matrix such as silica-alumina. This catalyst is suitable for cracking and hydrocracking hydrocarbons.

U.S. Pat. No. 3,925,195 describes a cracking process utilizing a catalyst comprising a mixture of a rare earth hydrogen exchanged Y-type zeolite, hydrogen or transition metal exchanged mordenite, a calcium exchanged A type zeolite or hydrogen exchanged erionite and an amorphous matrix. .

U.S. Pat. No. 3,764,520 describes a catalyst in which a zeolite having a pore size in the range of 6 to 15 angstroms and a zeolite having a pore size of less than 6 angstroms are combined with an inorganic oxide support. This catalyst is highly selective for use in hydrocarbon conversion processes.

U.S. Pat. No. 4,477,336 describes a cracking catalyst composition containing a mixture of non-dealuminized Y zeolite having a unit cell size of 24.6 ± 0.1 angstroms and dealuminized Y zeolite smaller than 24.4 angstroms.

SUMMARY OF THE INVENTION According to the present invention, a first Y-type crystalline aluminosilicate zeolite component and a second Y-type crystalline aluminosilicate zeolite component are intimately mixed with a heat-resistant inorganic oxide matrix, 1 and 2 zeolite is about 24.2
Provided is a catalyst composition having an average unit cell size in the range of 0 to 24.35 angstroms, wherein the difference between the average unit cell sizes of the first and second zeolites is at least 0.1 angstrom.

In another embodiment, the present invention provides that the hydrogenation component, the first Y-type crystalline aluminosilicate component, and the second Y-type crystalline aluminosilicate component are intimately mixed with the refractory inorganic oxide matrix, The first and second zeolite are about 2
Provided is a hydrocracking catalyst composition having an average unit cell size in the range of 4.20 to 24.35 angstroms, wherein the difference between the average unit cell size of the first and second zeolites is at least 0.1 angstrom.

The invention further uses any of the above catalyst compositions,
Provide a catalytic hydrocracking process for producing middle distillates with boiling points below 700 ° F (371 ° C).

DETAILED DESCRIPTION OF THE INVENTION The catalyst composition of the present invention contains at least two Y-zeolite components in combination with an inorganic matrix.

The prior art teaches that zeolitic catalysts can be produced from natural or synthetic zeolites and that they can be used for hydrocarbon conversion. Known zeolites include natural zeolites such as faujasite, mordenite, erionite and chabazite, and synthetic zeolites such as zeolites A, L, S, T, X and Y. In general, zeolite is a metal aluminosilicate having a crystal structure, and each crystal has a relatively large adsorption region. Basically, zeolite is SiO ₄ and Al
It has the three-dimensional skeleton of O ₄ tetrahedra, which is bridged by covalent oxygen atoms. The ionic valence of the aluminum-containing tetrahedra is balanced by the inclusion of cations such as metal ions, ammonium ions, amine complexes or hydrogen ions in the crystal. The voids within the pores can be occupied by water or other adsorbable molecules. Crystalline zeolites are usually produced or synthesized in the alkali metal form, which is not normally active in the catalytic cracking of hydrocarbons.

The present invention uses a zeolite component having cracking activity.
In order to obtain zeolites with decomposing activity, the alkali metal is usually replaced by cations containing polyvalent metals, hydrogen ions or hydrogen ion precursors (ie ammonium ions). This cation exchange is generally carried out by ion exchange known in the art, and sodium-type or other alkali metal-type zeolites include hydrogen ions, ammonium ions,
It is contacted with an aqueous solution containing rare earth ions or other suitable cations. If some of the sodium ions are replaced, zeolite with decomposition activity can be obtained, but the alkali metal content is converted to alkali metal oxides and it is 5 wt%.
The following, preferably less than 1 wt%, more preferably 0.5 wt%
When the amount is reduced below, a substance having substantial decomposition activity can be obtained.

Y-type zeolite is described in U.S. Pat. No. 3130007, which is incorporated herein by reference. The crystals of zeolite Y are basically SiO ₄ bridged by covalent oxygen atoms.
And in the three-dimensional skeleton of tetrahedron of AlO ₄ . The ionic valence of tetrahedron containing aluminum is balanced by cations such as alkali metal ions present within the aluminosilicate framework. The voids in the skeleton are occupied by water molecules.

The chemical formula of zeolite Y is expressed as follows in terms of the number of moles of oxide.

0.9 ± 0.2 Na ₂ O: Al ₂ O ₃ : wSiO ₂ : xH ₂ O where w is greater than 3 and up to about 6 and x is up to about 9.

The Y-type zeolite used in the present invention can be modified by known techniques. Y-type zeolite hydrothermally treated at a temperature of 500 ° C. or higher is preferable. Hydrothermal treatment is described in Dwyer, J, Zeolitic Structure, Composition and Catalysts, Chemistry-and-Industry, Issue No. 7, April 2, 1984, which is incorporated herein by reference.

Regardless of the type of Y zeolite used, the unit cell size of each zeolite component should be in the range of about 24.20 to 24.35 angstroms. In a preferred embodiment, the composition of the present invention contains first and second zeolite components having unit cell dimensions in the range of 24.20 to 24.35 Angstroms. The average unit cell size difference between the two zeolite components is at least 0.1 angstrom. The weight ratio of the first zeolite component to the second zeolite component is about 0.1-10: 1, preferably 0.1: 0.1. The first zeolite component is in an amount of about 1.0-20.0 wt%, preferably
Present in an amount of 5.0 wt%. The second zeolite component is about 1.0 to 2
It is present in an amount of 0.0 wt%, preferably 5.0 wt%.

The catalyst composition contains a refractory inorganic oxide matrix. Its content is in the range of 2-98 wt%, preferably 5-98 wt%. The matrix comprises known refractory inorganic oxides such as alumina, magnesia, zirconia, etc. and mixtures thereof.

The preferred matrix is silica-alumina or alumina. The most preferred matrix is a mixture of silica-alumina and alumina with an amount of silica-alumina in the range 5-98 wt% of the matrix and a total silica content of about 1-75 wt%.

The silica-alumina matrix is preferably a composite of silica and alumina. As a specific example, a satisfactory matrix material contains equimolar amounts of silica and alumina, or 63 wt% silica. Generally, the matrix contains about 10-90 wt% alumina. This matrix can be prepared by any of the many techniques well known in the art. Such techniques include:
Acid treatment of natural clay, sand or earth, co-precipitation from hydrosols or sequential precipitation is included. These techniques are often combined with one or more activation treatments such as hot oil aging, steaming, drying, oxidation, reduction, calcination and the like. The pore structure of the matrix or carrier, which is usually defined by surface area, pore diameter and pore volume, is such that the hydrosol and / or hydrogel is aged under controlled acidic or basic conditions at ambient or elevated temperatures, etc. Is expressed in a specific range by a suitable means, or by gelling the carrier at a critical pH or by treating the carrier with various inorganic or organic reagents. Suitable matrices for use in the method of the present invention have surface areas of about 200 to 400 m ² / g and about 20 to about
Pore diameter of 300 angstrom, about 0.10 to about 0.80 ml
It has a pore volume of / g and an apparent bulk density of about 0.50 to about 0.90 g / cc.

The alumina matrix may be any of various hydrated aluminum oxides, such as boehmite structure α-alumina hydrate, gypsite structure α-alumina trihydrate, and bayerite structure β-alumina trihydrate. Any alumina gel can be used. A particularly preferred alumina is called Ziegler Alumina, which is used in the synthesis reaction of Ziegler higher alcohols described in Zigler U.S. Pat. Characterized as a by-product. The preferred alumina is currently available under the trade name "Catapal" from the Conoco Chemical Division of Continental Oil Company. This substance is an extremely pure α-alumina hydrate (boehmite), and changes to high-purity γ-alumina when calcined at a high temperature.

The exact physical and / or chemical properties of the catalyst of the present invention are
It should be noted that the scope of the present invention is not limited. For example, the catalyst of the present invention can be packed into the reaction zone as a fixed bed in various shapes such as pills, pellets, granules, crushed pieces, spheres, and the feed can be fixed in liquid phase, gas phase or gas-liquid mixed phase. The bed can be passed up or down. Furthermore, it is also possible to prepare the catalyst in a shape suitable for a moving bed reaction zone in which the hydrocarbon feedstock and the catalyst pass countercurrently and cocurrently, or a disturbed bed of catalyst with a fine feedstock. It is also possible to prepare the catalyst in a shape suitable for a suspension process in which the fluid is passed upwards and the catalyst is suspended in the feedstock and the suspension mixture is conveyed to the reaction zone. In the above process, the reaction products are separated from the catalyst, returned to atmospheric pressure, and fractionally distilled to recover the desired components. Hydrogen and unreacted materials are optionally recycled.

The catalyst particles can be prepared by any method known in the art, including the well-known oil drop method and extrusion method. In the oil drop method, the selected zeolite powder is first suspended in a suitable sol. Active metal components are also added to this sol. Next, the sol mixture is supplied as droplets in an oil bath that is kept at elevated temperature, and is kept in the oil bath until the sol droplets become gelled particles. Then, the spherical particles are taken out from the oil bath and aged in the suspension medium at an elevated temperature for an appropriate time. The spherical particles are then dried and calcined. If an alumina or silica-alumina oxide matrix is desired, the oil drop method can follow the methods of U.S. Pat.Nos. 2620314 and 3003972, respectively, and thus these U.S. Pat. To do.

A second preferred method of preparing the catalyst composition of the present invention is
This is a method of kneading the selected zeolite, alumina, and amorphous silica-alumina. Prior to mixing, the components are preferably ground into powder. Active metal components can also be added to the mixture. After kneading, it is extruded from a die having an appropriate opening such as a circular opening to obtain a cylindrical extrudate. The extrudate is cut to a length of 1/2 to 1/4 inch, dried and then calcined under known conditions at elevated temperature.

Separately from mixing before or during the oil drop or extrusion operation, molding the selected zeolite and the heat-resistant inorganic oxide material, then introducing the hydrogenation component into the catalyst by impregnation, drying and firing. You can also The hydrogenation component can be introduced by any method known in the art such as an evaporation method, a dipping method, and a vacuum impregnation method. Generally, the dried and calcined particles are contacted with one or more solutions containing dissolved desired hydrogenation components. After a suitable contact time, the composition particles are dried and calcined to prepare the final catalyst particles.

The hydrogenation component of the present invention is a catalytically active component selected from Group VIB and Group VIII metals and compounds thereof. Generally, the amount of catalytically active component present in the final catalyst is small compared to the other components mentioned above which have been incorporated therein. The Group VIII component generally comprises from about 0.1 to about 20 wt% of the final catalyst composition, preferably from about 1 to about 15 wt%, on an elemental basis. The Group VIB component is about 0.05 to about 15 wt% of the final catalyst composition, preferably about 0.5 to about 1 based on the element basis.
It accounts for 2 wt%. Such hydrogenated components include molybdenum, tungsten, chromium, iron, cobalt, nickel, platinum,
Included are metallic components such as palladium, iridium, osmium, rhodium, ruthenium and mixtures thereof.

If desired, the phosphorus component can be introduced into the catalyst. Phosphorus can be introduced by mixing the carrier material with a phosphorus-containing compound prior to particle shaping or by incorporating phosphoric acid in the impregnating solution. Usually, phosphorus is present in the catalyst in the range of 1 to 50% by weight, preferably 3 to 25% by weight in terms of P2O5.

Furthermore, boron can be present in the catalyst. Boron can be incorporated into the composition in either elemental or compound form by any of the methods described above. That is, the boron can be introduced during molding of the particles or it can be present in the impregnating solution as boric acid. Additionally, boron can be incorporated into the framework of one or both selected zeolites. In the latter case, the Y-type zeolite is reformed to form silica-alumina-boron-zeolite.

The catalyst calcined in air is considered to have hydrogenation components in the form of oxides. If desired, the catalyst may be hydrogenated by contacting it with a reducing atmosphere containing hydrogen sulfide at elevated temperature. The components can be converted to the sulphide form.
The catalyst can be sulphurized by contacting it with a sulfur-containing feedstock in the as-used condition, or it can be sulphided prior to contact with the feedstock by exposing the composition to a reducing atmosphere immediately after firing.

The catalysts described above are particularly useful in hydrocracking to convert hydrocarbon feedstocks to useful products with relatively low average boiling points and low average molecular weights. In particular, the catalysts mentioned above are about 300-700.
It is useful for producing middle distillates having boiling points in the range of ° F (149 to 371 ° C). The catalyst is also effective for hydrogenation reactions such as hydrodenitrogenation and hydrodehydrogenation of hydrocarbons. Typical feedstocks that can be processed include all mineral oils,
Synthetic oils and fractions thereof are included. Thus, feedstocks such as straight run gas oil, vacuum gas oil, atmospheric residual oil, deasphalted vacuum residual oil, coker fraction and catalytic cracker fraction,
It can be treated with the catalyst of the present invention. Preferred feedstocks include gas oils, with approximately 50 wt% or more having a boiling point of 700 ° F (371 ° C) or more.

The reaction conditions are those conventionally used in hydrocracking processes. The reaction temperature is in the range of 200 to 1500 ° F (93 to 816 ° C), preferably 600 to 1200 ° F (316 to 649 ° C). The reaction pressure is in the range of atmospheric pressure to 3000 psig (0 to 20685 kpa gauge), preferably 200 to 3000 psig (1379 to 20685 kpa gauge). The contact time is from about 0.1 to 15 hr ^-1 corresponding to a liquid hourly space velocity (LHSV), preferably in the range of about 0.2~12hr ^-1. Hydrogen circulation ratio of the raw material per barrel from 1,000 to 50,000 standard cubic feet (178~8900m ³ H ₂ / 1m ³ material), preferably 2,000 to 30,000 standard cubic feet (356~5340m ³ /
m ³ ) range.

The following examples are provided for the purpose of illustration and not limitation of the invention, as they have excellent activity, selectivity and stability in producing middle distillates from gas oil by hydrocracking. A catalyst with properties is shown.

Example 1 A modified Y zeolite is prepared by steaming a powdered zeolite having a unit cell size of about 24.56 Å at 1000-1500 ° F (538-816 ° C) under atmospheric pressure for 0.5-24 hours. did. The unit cell size of this modified zeolite can be adjusted by changing the steaming conditions. Table 1 shows modified Y-zeolites with different unit cell sizes prepared by the above method and their steaming conditions.

Example 2 A modified type Y of Example 1 was added to a heat-resistant oxide matrix mixture of silica-alumina and alumina so as to obtain an extruded product containing 5 wt% zeolite excluding volatile matter and 95 wt% oxide matrix. Type zeolite was mixed. The resulting mixture was extruded into approximately 1/16 inch x 1/2 inch cylinders. The molding is dried and then 60% in air.
It was baked at 0 ° C. for 2 hours. Thereafter, as the final catalyst is obtained containing 1.0 wt% of elemental nickel and 10.0 wt% of elemental tungsten, a firing particles of ammonium metatungstate and nickel nitrate _{(Ni (NO 3) 2 ·} 6H 2
An aqueous solution of O) was co-impregnated by evaporation. Then impregnation catalyst
It was baked at 343 ° C. for 45 minutes, and further baked at 593 ° C. for 90 minutes.

Three catalyst compositions containing one of the modified Y-type zeolite prepared in Example 1 were prepared by the above method. Catalysts Nos. 1, 2 and 3 were prepared using a carrier containing 5 wt% of any one of the zeolites A, B and C of Example 1 and 95 wt% of an oxide matrix. Catalyst No. 4 was produced using a carrier containing 10 wt% of zeolite B of Example 1 and 90 wt% of an oxide matrix. Table 2 shows the properties of the catalysts No. 1 to No. 4 and their supports.

Example 3 First, the zeolite A and the zeolite C of Example 1 were mixed in the same parts by weight to obtain an extruded product containing 10 wt% of all zeolite and 90 wt% of an oxide matrix. Was mixed with the same refractory oxide mixture as catalyst No. 4. This mixture was extruded in exactly the same manner as in Example 2 and fired to impregnate it with a metal component. Table 2 shows the properties of catalyst No. 5 thus obtained and its carrier.

It should be noted here that zeolite A (unit cell size
Since 24.25 angstroms) and zeolite C (unit cell size 24.35 angstroms) are mixed in equal amounts, the average unit cell size of the mixed zeolite is 24.30 angstroms.

Example 4 The activity of each catalyst described above and the selectivity for middle distillates were
It tested by the following method.

A vacuum gas oil of the nature shown in Table 3 was passed on a single-flow basis through an isothermal reactor containing 75 cc of catalyst particles mixed with about 29 cc of 60-80 mesh (250-177 microns) quartz.
Operating parameters are 2000psig (13790kpa gauge), 1.0L
The circulation rate of HSV and hydrogen with a purity of 90-95% was 10,000 standard cubic feet / barrel (1780 m ³ / m ³ ), and the test period was about 4 days. The reaction temperature was adjusted so that a product having a boiling point of 700 ° F (371 ° C) or less was obtained at a conversion of 70 wt%. The conversion was calculated from the liquid chromatographic boiling range analysis of the product.
The test results are shown in Table 4.

As is clear from the results shown in Table 4, catalyst No. 5 (24.30A
Containing 10.0 wt% zeolite with an average lattice size of
Gives a yield similar to that of catalyst No. 2 (containing 5 wt% zeolite having a lattice size of 24.30A), but its activity is 1
As high as 2 ° F (6.6 ° C). In addition, comparing with catalyst No. 4 (containing 10 wt% zeolite having a lattice size of 24.30A),
Catalyst No. 5 is not only high at 6 ° F (3.3 ° C) but also 300-7
Selectivity for desired middle distillates at 00 ° F (149-371 ° C)
1.9 wt% increase.

Claims (4)

[Claims] 1. A carrier containing a first modified Y zeolite component having a unit cell size in the range of 24.20 to 24.35 angstroms in intimate admixture with a heat-resistant inorganic oxide matrix, and a catalytically effective amount. In a hydrocracking catalyst composed of a combination with a hydrogenation component, the unit cell size is 24.20 to 24.
The second modified Y zeolite component in the range of 35 Å is intimately mixed with the heat-resistant inorganic oxide matrix, and the unit cell size of the first and second modified Y zeolite components is at least 0.1 Å. A hydrocracking catalyst characterized by being used with a difference of. 2. The catalyst according to claim 1, wherein the weight ratio of the first modified Y zeolite to the second modified Y zeolite is in the range of 0.1: 1 to 10: 1. 3. A first modified Y zeolite having an average unit cell size of about 24.25 angstroms and a second modified Y zeolite having an average unit cell size of about 24.34 angstroms. The catalyst according to item 1. 4. The first modified Y zeolite is 1.0 to 20.0 wt.
% Second content of the second modified Y zeolite, 1.0-20.
The catalyst according to claim 1, which is contained in an amount of 0 wt%.