JPH03212494A - Manufacture of intermediate fraction by hydrocracking and catalyst composition used therein - Google Patents

Abstract

PURPOSE: To convert a hydrocarbon feed stream to an intermediate distillate in a highly selective and active reaction by bringing it into contact with a specified zeolite-based catalyst composition under a hydrocracking condition.

CONSTITUTION: A hydrocarbon feed stream comprising an intermediate fraction with a boiling point of 149-371°C is brought into contact with a catalyst composition comprising mainly of a heat-resistant inorganic oxide matrix and a hydrogen form Y type zeolite with a unit cell size of 24.20-14.40 Å under a hydrocracking condition to recover a hydrocracking product stream, wherein the zeolite has an ion exchange capacity of more than 0.07 and a low acidity with a bound hydroxyl content low enough to provide an NH₃-TPD acidity strength of less than 2.

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention provides highly selective mid-bar
rel) or a hydrogenolysis catalyst from which a middle distillate is obtained. More specifically, the present invention uses heavy hydrocarbons having boiling points of 300 to 300.
700”F (149-371℃) (7)ffillm
(7) Concerning a highly selective catalytic hydrogenolysis process for conversion to middle distillates The present invention is characterized by the use of a new Y zeolite with low acidity strength.

[Background of the invention]

Hydrocracking is a petroleum refining process for partially cracking hydrocarbon-based materials in the presence of hydrogen to obtain more desirable low molecular weight hydrocarbon products.

The increasing demand for middle distillates, such as jet fuel and diesel fuel, has resulted in lower boiling points for middle distillates compared to cracking processes that degrade the feedstock to gas or coke with little effect and therefore do not consume heat, i.e. hydrogen. Industrial interest in the hydrogenolysis process has increased because it yields products with a high range of fractions.

A critical element for competitive hydrocracking processes is the availability of special catalysts that are highly active for both cracking and hydrogenation. Many of these bifunctional catalysts are well known in the prior art. In general, cracking activity, a measure of the conversion of feedstock to product, is mostly due to the solid acid component present in the catalyst base. Hydrogenation activity, on the other hand, is usually due to various metals deposited on the catalyst base.

These metals are most often listed in VI of the periodic table of elements.
Selected from Group B and Group 1.

Common catalysts used in the hydrocracking industry for the production of middle distillates are silica-alumina mixtures or periodic table V deposited on amorphous heat-resistant inorganic oxide substrates such as alumina.
A metal and/or a metal compound selected from Group IB or Group 1.

Significant recent industrial activity has been directed towards the development of cracking catalysts containing crystalline aluminosilicates in the catalyst base.

Generally, zeolitic aluminosilicates have a greater total acidity than amorphous oxides and therefore have higher decomposition activity. Because of this characteristic, zeolites are believed to provide excellent catalytic effects for hydrocarbon conversion. In research and development of zeolite-based hydrogenolysis catalysts, Y-type zeolite, which was first disclosed in US Pat. No. 3,130,007, has attracted particular attention. The catalytic mechanism of Y-type zeolite is not fully understood, but hydrocracking catalysts containing zeolite Y not only show great activity in the production of middle distillates;
Good selectivity towards the desired middle distillate products has also been observed.

[Prior art]

Conventional zeolite-containing hydrogenolysis catalysts are zeolite Y or modified products thereof in a heat-resistant inorganic oxide matrix. For example, Zeolite Y increases the molar ratio of silica and alumina,
It can also be modified by reducing the size of the unit cell.

U.S. Pat. No. 4,419,271 to J. W. Ward includes a crystalline aluminosilicate zeolite with hydrocarbon cracking activity and one or more hydrogen species on a silica-alumina dispersed base in an alumina matrix. Discloses a hydrocarbon conversion catalyst useful for hydrogenolysis supporting a chemical component. This patent teaches that replacement of the alkali metal with a polyvalent metal-containing cation, hydrogen ion or hydrogen ion precursor (generally carried out by ion exchange) is necessary to obtain a zeolite with the desired cracking activity. . Alkali metal component less than 5 wt%, preferably 0.5
Reduction below wt% (calculated as reduced alkali gold oxide) yields a material with substantial cracking activity. The patent also states that the most preferred zeolites for use as a component of the hydrocracking catalyst composition have a silica/alumina ratio of about 3.
．． 5 to 6.0, and the surface area is about 500 to 700 bo/g.

Silica/alumina with a unit cell size of about 24.25 to 2445 cells, a water adsorption capacity of less than about 8 wt% relative to zeolite (at a partial pressure of water vapor of 4.6 mm and 25°C), and an equivalent ion exchange capacity. It teaches that the modified Y zeolite has a sodium ratio of less than 20% compared to the sodium Y zeolite.

U.S. Pat. No. 4,401,556 to Ro[), Bexman and J.A. Rabo has a silica/alumina molar ratio of 4.5 to 35, an essential X-ray powder diffraction pattern of zeolite Y, and an ion exchange capacity. is less than 0.070, the unit cell size is 24.20 to 24.45 people, the surface area is 350 Bo/g (B-E-T) or more, the water vapor absorption capacity is 25°C, and p/p' = 0. less than 5.00 wt% in 10,
and superhydrophobic zeolite Y (UHP-Y) characterized by having a residual butanol test value of 0.40 wt% or less.
) is disclosed.

and U.S. Patent No. 4.517.073 to J.W. Ward.
In addition to dispersing silica-alumina in alumina,
Hydrocracking catalysts are disclosed having an active hydrogenation component on a support comprising Y-type zeolite with a silica/alumina molar ratio of about 6.0 or greater. The zeolite used in the catalyst for the hydrocracking process of this patent has essentially the crystal structure of Y zeolite, has an alkali metal content of less than 1.5 wt% (calculated as the sum of metal monoxides), and has a typical The unit cell size is 24.65 Å or less. The preferred molar ratio of silica/alumina is 6 to 20, and when this molar ratio is less than 20, the water vapor adsorption capacity of the zeolite of this patent is more than 20 wt% based on the anhydrous zeolite at 25°C and the partial pressure of water vapor 46 nwnHg. Also, the preferred adsorption capacity for oxygen is 100 mm Hg and -183'
The content is 25 wt%.

The above patents are considered to be illustrative of the state of the art for Y-type zeolite-based hydrogenolysis catalysts.

The catalyst for hydrogenolysis taught by the prior art is silica/
Alumina molar ratio, unit cell dimensions, ion exchange capacity,
It was characterized by its surface area and absorption capacity for water. The bifunctional catalyst used in the hydrogen cracking catalyst provides cracking and hydrogenation activities, and it is well known in this field that the acidity of the catalyst components affects the cracking activity of the catalyst. For example, Dwyer and New cited below.
The article by Sam discusses the causes and effects of zeolite acidity. However, despite the enormous efforts of researchers skilled in the field of hydrogenolysis, the effect of hydroxyl concentration on selectivity, which is directly related to the acidic strength of the cracking component (such as Y-type zeolite), has been virtually ignored. I came.

Dehydroxylation studies described in the literature are generally insufficient. The exceptions are C0D, Chan
There is a series of publications such as U.S. Pat. No. 4,790,928 to G et al. This document describes ZSM by selective dehydroxylation.
-5 and other intermediate pore zeolites. The obtained zeolite contains low feedstock oil,
That is, it is taught that it is useful for catalytic dewaxing of petroleum fractions such as vacuum gas oil. Dehydroxylation occurs upon calcination above 600°C (ii72'F) in the absence of water.

American Chemical 5ociety
Monograph 171 (JuteA, Rabo
(Eds.), pp. 140-147, studies on the hydroxyl groups of Y zeolite and the effects of calcination are discussed.

N. Y. Chen, US Pat. No. 4,263,129, uses a low acidity catalyst to perform hydrogenolysis.

However, this document describes ZS with a silica/alumina ratio of 12 or more.
It is thought that there is a limitation that M-5 is used.

This low acidity is preferably obtained by extensive ion exchange of the zeolite with sodium or other alkali metals to give a high sodium content, but the method of the present invention does not contain sodium-containing Y with low amount and low silica/alumina ratio
It differs from this document in that zeolite is used.

J.W. Ward, US Pat. No. 3,929,672, compares the effects of steam and dry calcination on Y zeolite. It is pointed out that dry calcination causes loss of crystallinity.

[Summary of the invention]

In a broad sense, the present invention has a unit cell size of about 24,20
~24.40 people and TPD acidity strength is approximately 2.0
The present invention provides a selective hydrogenolysis process for the production of middle distillates using a catalyst based on hydrogen-form crystalline Y zeolite having sufficiently low levels of surface hydroxyl groups to be less than 0. This zeolite is preferably dehydroxylated by dry calcination.

The present invention comprises (i) a hydrogenation component, (ii) a heat-resistant inorganic oxide matrix mainly composed of alumina, and (iii) a unit cell size of 24.20 to 24.40, and NH3- T
It is characterized as a selective hydrocracking catalyst for the production of middle barrel fractions consisting of a combination of crystalline hydrogen form Y aluminosilicate zeolites with a PD acidity strength of less than 1.50.

[Detailed description of the invention]

It is an object of the present invention to provide improved hydrocracking catalysts and methods. It is also an object of the present invention to provide improved hydrocracking catalysts that exhibit superior activity and selectivity towards middle distillate products.

It has now been discovered that Y-type zeolites, which have a low concentration of hydroxyl groups bound to the zeolite surface, provide excellent hydrogenolysis catalysts. This catalyst is ammonia thermometer theory 111 (ammonia temperature).
programmed desorption) (NH
3-TPO) was found to be highly selective in the hydrocracking process for producing middle distillates.

The hydrogenolyzable composition of the present invention is mainly composed of crystalline Y-type zeolite. Type Y zeolites are generally disclosed in US Pat. No. 3,130,007, incorporated herein by reference.

The chemical formula of zeolite Y expressed in moles of oxide is 0.9±0.2Na20:AQ203:w
It can be written as si02:xH20 (where W represents a value of 3 to approximately 6, and X represents a value of approximately 9 or less).

The classical structure of zeolite Y is a three-dimensional framework of 5i04 and AQ04 tetrahedra cross-linked by covalent oxygen atoms. The electron valence of a tetrahedron containing aluminum is a metal ion,
Balanced by the presence of cations such as rare earth metal ions, alkali metal ions, ammonium ions, amine complexes, and hydrogen ions. Void spaces in the skeleton can be occupied by water molecules. Usually, this crystalline zeolite is obtained or made in the alkali metal state. The classification of materials as zeolite Y is basically based on the above formula and the materials exhibiting the well-known X-ray diffraction pattern. The structure of Y zeolites contains germanium, gallium, phosphorus or boron along with or in place of traditional silica and alumina.

The acidity of zeolites has been the subject of considerable research and speculation. For example, the impact of acidity on catalytic activity and the relationship between composition and acid strength of zeolites have been investigated in Ch.
198 of emistry and indu-stry
April 2, 2014 edition 258 In a section with true JohnDvy e
r is discussing. This term is active Brønsted (B
ronsted) sites are cited as evidence of hydroxyls within the zeolite channels. Two types of hydroxyls are described: surface or terminal hydroxyls in relatively large pores and bridging hydroxyls.

Additionally, acidity, composition, catalyst activity and catalyst selectivity are discussed. It should be noted that the selectivity of the product is characterized by the fact that it is not determined or influenced by acidity, but rather by the impact on pore geometry and size and the diffusion limit to selective internal sites. be.

5science March 7, 1986 edition (Vol. 231, 1
In a section on page 093), J OM, Newsam states that most of the reactions involved in catalytic cracking involve acid sites located within the zeolite. Such Brønsted acidity is primarily due to bridging hydroxyl groups. The acid sites are believed to be concentrated or originating from the protonated tetrahedral aluminum of the silica-rich framework of the zeolite.

As illustrated by the data presented below, the selectivity of hydrogen form Y zeolites for producing middle distillate products is directly correlated to the acid strength of the zeolite, which in turn is set by the concentration of hydroxyl groups on the zeolite. It was discovered that.

Both the use and composition of such low hydroxyl zeolite-based hydrocracking catalyst compositions are believed to be novel.

Since it is currently not possible to directly measure the concentration of hydroxyl groups, this measurement has to be carried out indirectly.

The analytical method of choice is to measure the acidity strength of the zeolite. This is directly correlated to the concentration of hydroxyl groups.

it is conceivable that.

The ammonia thermometer R(NH3-TPD) is widely used and is considered an effective method to measure the acidity strength of zeolites. (Hidalgo,
C, V, et al., “Measurement of acidity of various zeolites by temperature-planned desorption of ammonia”, J, Cataly
sis, Vol. 85, NIL 2, pp. 362-369 (
(1984). This measurement method is cited here. ) Ammonia is an excellent probe molecule for the TPD method.

The small size of this molecule allows it to pass through pores very easily, while its strong basicity makes it easy to stabilize on acid sites. The TPD method is preferred because it is relatively simple, requires less effort, and can be accurately reproduced.

In the NH3-TPD method used here, a sample of zeolite (0.250±0.001g) was first heated at 5006 g in air.
Preheat the preheated zeolite by heating at a flow rate of 60 cc/min for 75 min at C and then at a flow rate of 60 cc/min in helium for 15 min at 500 °C. Cool to room temperature over 20 minutes. To maintain equilibrium, the zeolite sample is saturated five times with ammonia gas 1ace (atmospheric conditions). Next, this saturated zeolite was heated at room temperature for 35 minutes.
Purify with helium at a flow rate of 60 cc/min. This gas stream is then immediately gas chromatographed with heating up to 650°C with a planned ramp temperature of 8.33°C and 7 minutes. The desorption of ammonia is then monitored with a recorder over a period of 75 minutes at a temperature of 25-500°C.

The area of the desorption curve obtained by the gas chromatograph recorder correlates with the total amount of ammonia desorbed. Analysis of the exhaust gas using a mass spectrometer showed that the desorption of impurities at temperatures of 50 to 500°C was negligible. To standardize the desorption curve, the desorbed ammonia was converted to IO%H2sO
4 solution and quantified using a known method. The amount of ammonia desorbed per unit area of the desorption curve is 0 per unit area.
．． It was determined to be 0.038±0.004 mmol.

The strength of NH3-TPD acidity is 25~s o o ”c
It was determined by integrating the desorption curve between Next, multiply the area of the curve by a factor of 0.038 m mol per unit area, and then divide by the weight of the sample (2.50 g) to m
The strength of NH3-TPD acidity in mol/g is obtained. Therefore, for example, if the integration between 25 and 500 degrees Celsius results in a total unit area of 10.0, then the IO unit area x 0,038 m
moleNH3/unit area 70.250 g sample =
It is calculated to be 1.52 mmole/g sample.

All NH3-TPD acidity strengths considered in this invention are based on units of mmole/g sample.

For the sake of simplicity, the unit display of the NH3-TPD value referred to here has been omitted. Data reproduction of acidity strength by NH3-TPD requires the rate of temperature rise, sample size, gas flow,
Accurate repetition of experimental parameters such as equilibrium temperature is required. It is therefore often difficult to compare acidity strengths obtained with different methods. In any case, the acidity strength considered in the present invention is the NH
3-In addition to the values measured by the TPD test,
It should be understood that equivalent values obtained using substitution methods for the same sample are also included.

The Y zeolite used in the method of the present invention is silica/
An alumina ratio of less than 6.0 is suitable.

The Y-type zeolite used in the present invention has a unit cell size of about 24.20 to 24.45 cells.

Preferably, the unit cell size of this zeolite is about 24
．． 20 to 24.40 people, most preferably about 24,
There are 30 people. Although the prior art discloses that zeolite-containing hydrogenolysis catalysts are sensitive to changes in the zeolite unit cell size, acidity strength is believed to be independent of this parameter. The decrease in acidity due to the decrease in unit cell size is due to the decrease in aluminum content in the zeolite, and this effect is due to the different acidity measurements of zeolites with the same silica/alumina ratio and/or unit cell size. It does not concern the law.

Type Y zeolites considered in this invention should have an NH3-TPD acidity strength of less than about 2.00. This acidity strength is preferably less than about 1.50, and about 1.
．． Most preferably, it is less than or equal to 50, particularly in the range from about 0.1 to about 0.70.

The actual procedure for obtaining hydrogen form zeolite Y with low acidity strength is not considered important to the present invention. Accordingly, the contemplated hydrocracking catalyst can be made from any feedstock having zeolite Y with an X-ray powder diffraction pattern essentially as described in U.S. Pat. No. 3,130,007. The feedstock can be modified by any acidity reduction method known in the art to provide the desired hydrogen form zeolite.

Therefore, modification methods such as high-temperature hydrothermal treatment, calcination, immersion, or reaction with systems that prevent the strength of acidity, crystallization, and combinations thereof come into consideration.

The method of modification or production of the zeolite is not believed to be critical to the invention. Any hydrogen-form zeolite Y material having a suitably low hydroxyl group concentration can be used as the zeolite component of the hydrogenolysis catalyst of the present invention.

One way to reduce acidity strength is to reduce it to at least 0 at temperatures above 500℃.
．． Hydrothermal treatment is carried out for 5 hours.

The preferred acidity reduction method is at least 0.5 at 500°C or above.
It is calcined in dry air for an hour. A highly preferred method of effecting the desired dehydroxylation is to maintain the zeolite in the substantial absence of water at a temperature of at least 704°C or higher for at least one hour. The particular modification method used is not known to be critical to the invention.

It is contemplated that more than one different modification method may be employed.

The hydrogen cracking catalyst composition of the present invention contains 2 to 2 Y-type zeolites.
It should contain 0 wt%, preferably 2-10 wt%. This composition also serves as a support for the finished catalyst composition.
-98 wt%, preferably 5-95 wt% of a porous refractory inorganic oxide matrix. This base material may be made of known heat-resistant inorganic oxides such as alumina, magnesia, silica, titania, zirconia, silica-alumina, and combinations thereof.

The preferred matrix is silica-alumina or alumina.

The most preferable base material has a silica-alumina content of 4% relative to the base material.
It is a mixture of 5 to 90 wt% silica-alumina and alumina. This support also has an alumina content of about 5 to about 45
Preferably, it is wt%.

The silica-alumina component can be prepared by any of a number of methods rather well defined in the relevant prior art. These methods are acid treatment of natural clays or sands, coprecipitation from hydrosils or continuous precipitation. These methods include hot oil aging, steam treatment, drying, oxidation, reduction, calcination, etc.
It is often combined with more than one type of activation treatment. Usually, the pore structure of the support or carrier defined by surface area, pore diameter, and pore volume is at room temperature or at high temperature.

Certain limitations can be achieved by suitable means of aging the hydrosil and/or hydrogel in controlled acidic or basic conditions, or by gelling the support in a critical field, or by treating the support with various inorganic or organic agents. Can be a value.

The finished catalyst applicable to the hydrogen cracking method is approximately 200 to 700c.
al/g surface area, about 20 to about 300 people pore size, about 0
．． 10 to about 0.80 nm/g pore volume and about o, 50
It must have an apparent bulk density in the range of ~0.90 g/cc. A surface area of 350 rrf/g or more is highly preferred.

The alumina component of the catalyst may be any of various hydrated aluminum oxides or alumina gels such as alpha alumina hydrate having a boehmite structure, alpha alumina trihydrate having a gibbsite structure, and beta alumina trihydrate having a payerite structure. Particularly preferred aluminas are so-called Ziegler aluminas, 2iegler U.S. Pat.
No. 3.852 as a by-product of the Ziegler higher alcohol synthesis reaction as described in U.S. Pat.
．． No. 190 and No. 4.012.313. A preferred alumina is ContinentalO
i1's Conoco Chemical Divis
ion is currently available under the trade name 'Cata-pal'. This material is produced by high-temperature calcination to produce high-purity gamma-
Extremely high purity alpha alumina that becomes alumina
It is a hydrate (boehmite).

The detailed physical characteristics of the carrier material, such as shape and surface area, are not considered to limit the scope of the invention. The catalyst can be, for example, in the form of pills, pellets, particles, pieces, spheres, or trilobials arranged in a fixed bed in the reaction zone.
) can be present in various special shapes such as extrusions. or a moving bed reaction zone in which the hydrocarbon charge and the catalyst are passed either countercurrently or cocurrently, a fluidized solid process in which the charge is passed upwardly through a turbulent bed of ground catalyst, or the catalyst is slurried in the charge; The catalyst may be prepared in a form suitable for use in a suspension process in which the resulting mixture is transported to a reaction zone.

The charge feedstock can be passed through the reaction zone in liquid, gaseous or mixed phases and either in an upward or downward flow.

The catalyst particles may be prepared by any method known in the art, such as the well-known oil drop method or extrusion method. In the case of the oil drop method, the catalyst particles can be prepared by first suspending the selected zeolite powder in a suitable sol. An active metal component may be introduced into this sol. The sol mixture is then introduced as droplets into an oil bath maintained at an elevated temperature, and the sol droplets are held in the oil bath until they form stable gel spheres. The spherical particles are then removed from the oil bath and aged in a suspending medium at an elevated temperature for a suitable period of time. Next, the spherical particles are dried and calcined.

If an alumina or silica-alumina oxide matrix is desired, U.S. Pat. No. 2,620,314 is included for reference.
or No. 3.003.972.

A preferred method of preparing the catalyst composition of the present invention is to co-mill the selected zeolite with alumina and amorphous silica-alumina. Preferably, the mixed components are ground into powder before mixing.

At this time, active metal components can also be introduced into the mixture. After kneading, the mixture is extruded into molds with suitable openings, such as cylindrical or Grover's leaves, to give extrudates of the desired shape. Extrusions are 172-174 inches (1,27
~0.645 cm), then dried, calcined at high temperature, and further conditioned by methods known in the art.

A hydrogenation component may be added before or during operation of the oil drop method or extrusion method, but this component may be added after the selected zeolite and inorganic oxide materials have been shaped, dried, and calcined before soaking. It is preferable to mix the catalyst with the catalyst. The metal hydrogenation component may be impregnated into the particles by any method known in the art, such as evaporation, impregnation, vacuum immersion, or the like. Generally, after drying, the calcined particles contain the desired hydrogenation components in solution.
contact with a solution of more than one species. After a suitable contact time, the composition particles are dried and calcined to form finished catalyst particles. Further guidance on the preparation of suitable catalysts is provided by U.S. Pat. No. 4,588.
, No. 496, No. 4.600.498, and many other documents.

These patents provide guidelines for the production and use of hydroprocessing catalysts containing Y zeolite.

Hydrogenation components that come into consideration are catalytically active components selected from group VIB and group I metals and their compounds. Generally, the amount of hydrogenation component present in the final catalyst composition is small compared to the amounts of the other incorporated components. Generally, No.■
Group components are approximately 0 for the final catalyst composition calculated on an elemental basis.
．． 1 to about 30 wt%, preferably about 1 to about 15 wt%.

The Group VIB component is about 0.05 to about 30 wt%, preferably about 0.5 to about 30 wt% of the final catalyst composition, calculated on an elemental basis.
It is about 15 wt%. The hydrogenation components considered are molybdenum, tungsten, chromium, iron, cobalt, nickel,
One or more metals selected from platinum, palladium, iridium, osmium, rhodium, ludinium, and mixtures thereof.

The hydrogenated components exist mostly in the oxide form after calcination in air and, if desired, can be converted to the sulfide form by contacting with a reducing atmosphere containing hydrogen sulfide, mercaptans or other sulfur-containing compounds at elevated temperatures. It may be converted. The catalyst may be brought into contact with the sulfur-containing feedstock and there formed into a sulfide, or the composition may be exposed to a reducing atmosphere immediately after calcination and prior to contact with the feedstock to be made into a sulfide.

A phosphorus component may be introduced into the catalyst if desired.

The introduction of phosphorus can be carried out by mixing the support material with a phosphorus-containing compound before shaping it into particles, or by including phosphoric acid in the soaking solution. Usually, phosphorus is present in the catalyst at 1 to 30 wt%, preferably 3 to 30 wt%, calculated as P2O5.
It is present at 15 wt%.

Additionally, boron may be present in the catalyst composition in elemental or compound form and by any of the methods described above. Thus, boron may be introduced during the particle formation process, or it may be added and present in the soaking solution as a compound such as boric acid. Boron may also be introduced into the framework of selected zeolites, in the latter instance a modification of type Y zeolite is produced to form a silica-alumina-boron-zeolide.

The catalysts of this invention are particularly useful for hydrocracking hydrocarbon feedstocks into more valuable products with lower average boiling points and lower average molecular weights. This catalyst has a boiling point of about 300-700"F (149-371C) as measured by the appropriate A37M test method.
It is particularly useful in the production of middle distillates. Additionally, the catalysts are useful in hydrogenation reactions such as hydrodenitrification and hydrodesulfurization.

Typical examples of raw materials include virtually all heavy mineral and synthetic oils and their fractions. Therefore, raw materials such as straight-run gas oil, vacuum gas oil, demetalized oil, atmospheric residue, deasphalted vacuum residue, coker fraction, catalytic cracking fraction, shale oil, tar sand oil, coal liquor, etc. are considered. Preferred raw materials have a boiling point of 700
It is a light oil containing 50% by volume or more of components below (371'C) or higher. The hydrogenolyzed raw material may normally contain 1 ppm-1.0 wt% of nitrogen as an organic nitrogen compound. The feedstock typically contains a sufficient amount of sulfur-containing compounds such that the sulfur content is greater than 0.15 wt%. Further, it may contain 80vol% or more of a mononuclear and/or polynuclear aromatic compound.

The hydrocracking conditions used in the process of the present invention are the same as those commonly used in the field of hydrocracking. The hydrogenolysis temperature ranges from 400-1200F (204-649°C), preferably from 600-950'F (316-510°C). The reaction pressure ranges from atmospheric pressure to approximately 3,500 psig (24
, 132kPa gauge), preferably 200-300p
sig (1379-20,685 kPa gauge). The contact time is usually the hourly space velocity of the liquid (
LH3V) about 0.1 to 15/hr, preferably about 0.1
This corresponds to ~15/hr. Hydrogen circulation rate is l, θoo~so, ooo standard cubic feet per barrel of filling.
(scf/barrel) (178~8.888 standard rrri
rrt>, preferably 2,000 to 30,000 sc
f/barrel (355 to 5,333 standard bo/bo).

The reaction zone effluent is typically removed from the catalyst bed and, after partial condensation and gas-liquid separation, fractionated to recover various components. The hydrogen and, if desired, at least a portion of the unconverted heavy products are recycled to the reactor.

Therefore, the present invention requires at least 50% of the component with a boiling point of 371°C or higher
A hydrocarbon feed stream comprising % by volume of (i) a hydrogenation component, (i
i) a heat-resistant inorganic oxide matrix mainly composed of alumina, and (5) a unit cell size of 24.20 to 24.40, an ion exchange capacity greater than 0.07, and NH3-
Crystalline hydrogen form Y with a TPD acidity strength of less than about 1.50
type aluminosilicate zeolite, said zeolite being dehydroxylated by contacting with steam for 2 to 12 hours at a temperature of 676-780°C followed by dry calcination for at least 1 hour at a temperature of at least 426°C. and is characterized by a hydrocracking selective production process for mid-barrel cuts in which the catalyst is contacted with a catalyst composition maintained at hydrocracking conditions and a product stream is then recovered.

The following examples are provided for illustrative purposes and are not intended to limit the scope of the invention.

Example ■ This example compared the effectiveness of two different methods of reducing the acidity strength of zeolite. In part A, the raw zeolite was heated in the presence of steam and then dry-calcined, while in part B, the raw zeolite was heated in dry air. The acidity strength of zeolite is the above-mentioned NH3-TPD.
Measured by test. The raw material zeolite has a skeleton with a silica/alumina ratio in the range of 5:1 to 8:1. A framework with a silica/alumina ratio of about 6=1 is preferred. This ratio is not equivalent to the bulky silica/alumina ratios found in the literature. This zeolite has 0 sodium
Contains less than 0.01 wt%.

Part A A sample of ammonium exchanged Y zeolite, sold previously by Union Carbide and currently by UOP under the trade name LZ-Y82, was used. This zeolite (initial NH3-TPD acidity strength 2.60, unit cell size 24.56 people) was filled into an external heating type iO heat tube. Pressure of 14.7 psia (1 atmosphere absolute) and 1250-1450°F (676
~788°C) for 2 to 12 hours with pure steam generated from demineralized water. At the end of this selected heating time, the steam flow was stopped and the filling temperature was allowed to drop to room temperature in a stream of dry air over a period of 4 hours. During this process,
The zeolite was maintained at a temperature of at least 800'F (426C) for at least 1 hour.

Five zeolite samples (A, B, C, D and F) were similarly prepared at the temperatures and times shown in Table I. Analysis of the product sample showed a characteristic X-ray powder diffraction pattern of Zeolite Y. Unit cell size and NH3-
The strength of TPD acidity is shown in Table I.

This result reduces the unit cell size to the desired 24.20 to 24
．． It is shown that the acidity of the zeolite can be changed (reduced) to a preselected value while remaining within the range of 40. Therefore, the NH3-TPD acidity can be adjusted by the method of Part A, which includes a dry air calcination step after steam treatment.

(Leaving space below) Table 1 - Zeolite Steam Acidity Strength □-1 Genkasa Q Illusion Hijiku Thickening and Shang Sehi Bonzanmu History A 2 1250 (676)
24.36 1.50B 2 135
0 (732) 24,35 1.13C
21450 (788) 24,29 0
．． 65D 12 1450 (78g)
24,25 0.14E --24,3
61,30 F 6 1250 (676) 24,3
5 1.25 Bart B NH3-TPDAnother ammonia-exchanged Y zeolite powder with an acidity strength of 2.18 and a unit cell size of 24.37 (previously from Union Carbide and now from UO
It is sold by Company P under the trade name LZ-Y20. )
was charged into a manful furnace (no steam is present in this method). This material is used in the cited U.S. Patent No. 4,419,27.
No. 1 is considered to be representative of conventional zeolites intended for use in selective cracking catalysts for steam-treated mid-barrel fractions. This zeolite was heated to 1300”F (7
The temperature was increased to 0.04° C.), maintained at this temperature for 1 hour, and then cooled to room temperature. The product analysis results show the characteristic X-ray powder diffraction pattern of Y zeolite, and the unit cell size is 24.36 people, and the NH3-TPO acidity strength is 1.3.
It was 0. This zeolite is shown in Table 2 as labeled sample E.

This result shows that the dry calcination method did not significantly affect the size of the unit cell, and that the NH3-T of zeolite sample E
This shows that the PD acidity strength was reduced.

It is noteworthy that the processing in Part A also changed the unit cell size of the raw zeolite and the NH3-TPD acidity strength. However, in Part B, only the strength of the NH3-TPD acidity decreased, and the unit cell size of the raw zeolite remained virtually constant (24.37 vs. 24.36).

Thus, high temperature heating, or calcination, of zeolites in a relatively dry atmosphere, such as flowing nitrogen-containing gas without the addition of steam, may prove to be an effective method of reducing the hydroxyl group concentration of zeolites. This method can therefore be incorporated into the general catalyst preparation process whenever such low acidity and hydroxyl group concentrations are desired.

Without being limited by theory, the strength of acidity is independent of unit cell size and can be tailored to various combinations of heating in the presence of steam and dry air. However, the exact effect on the acidity strength of zeolites when heated with or without steam is not known.

The preferred preparation method yields a hydrogen-form zeolite with unit cells that are substantially unchanged in size compared to untreated zeolite. This dry calcination method is preferably used as the exclusive means of reducing the acidity and hydroxyl group concentration of the zeolite. If other methods such as dealumination or ion exchange are used, they are preferably used before this dry heat treatment. Preferably, dehydroxylation is carried out before introducing the treated zeolite into the formed catalyst particles.

It is believed that steam tends to inhibit the "dehydroxylation" of the zeolite in hydrothermal treatments. Steam is clearly preferred when a change in the unit cell size of the zeolite is desired as a goal of the treatment. The inventive process uses a low hydroxyl concentration zeolite rather than a steam treated zeolite.

Many of the conventionally used zeolites are characterized by their adsorption capacity for water. Such characteristics and methods for measuring them are described, for example, in the above-cited U.S. Pat. No. 4,401;
It is described in No. 556.

These zeolites are characterized by a water vapor adsorption capacity of less than 5,00 wt% at 25° C. and P/Po=0.10. Tests for water vapor adsorption capacity were not conducted on the test materials of this example. However, similarly processed materials from the same raw materials were later tested. The material equivalent to Zeolite C (used in Catalyst 3 below) and similarly subjected to hydrothermal treatment is approximately 2.5 wt.
% moisture adsorption capacity. No moisture adsorption capacity is available for Part B feedstock. It appears that the water adsorption capacity decreases in proportion to the intensity of the hydrotreating.

Example■ The purpose of this example is to determine the size of the unit cell and NH3-TP.
To investigate the influence of both D acidity strength on the selectivity and activity of the finished catalyst.

A catalyst composition is prepared by mixing zeolite powder and a heat-resistant oxide matrix mixture of alumina and alumina-silica in selected amounts such that the volatile content is 5 wt % zeolite and 95 wt % oxide matrix. I prepared something. The resulting mixture is approximately 1/16 x 172 inches (0.16 x 1.2
7 cm) into cylindrical pieces. After drying this extruded material, it was calcined in air at 650°C (343°C) for 2 hours. Next, the calcined particles were mixed with 1.0 wt % of elemental nickel and 10 wt % of elemental tungsten. It was evaporated and immersed in a solution of ammonium metatungstate and nickel nitrate (Ni(N 03) 2 .6H 20) in amounts sufficient to give a finished catalyst containing Owt. The soaked catalyst was then heated to 650'F (34
3°C) for 45 minutes and then 110°C (1'F (593°C)
℃) for 90 minutes. Six types of catalyst compositions, each containing one of the Y zeolites prepared in Example 2, were prepared in the manner described above. Table 2 shows details of the relevant performance of catalysts Nα1-6 containing zeolites A-F, respectively.

A catalyst was prepared using the zeolite raw material used in Parts A and B of Example (2) according to the above method.

Catalyst Nα7 was prepared with the zeolite feedstock from Part A (unit cell size = 24.56 people, NH3-TPD = 2.60), and catalyst Nα8 was prepared using the zeolite feedstock from Part B (
Unit cell size = 24.37 people, NH3-TPD
=2.18). The relevance of catalysts Nα7 and 8 is also shown in Table H.

(Left below) Hawk--W 1 A 24.36
1.502B
24,35 1.133
C24,290,654D 2
4.25 0.145 E
24.36 1.3
06 F 2445
1.257 Part A ingredients 2
4.56 2.608 Part B Feedstock 24.37 2.18 Each of the above catalysts was tested for activity and selectivity according to the following method. Preheated gas oil having the chemical and physical properties shown in Table 1 was passed in single flow through an isothermal reactor containing 75 cc of catalyst particles mixed with about 29 cc of 60-80 mesh quartz. Operating parameters are pressure 2000 psig (13,790
kPa gauge), LH3V1.0.90~b (1,778 standard rrf/rrr) and run length approximately 4
It is day.

The reaction temperature is a boiling point of 700'F (371°C) and a product strength of 85
It was adjusted to obtain a conversion rate of wt%. Conversion was calculated from liquid chromatographic boiling range analysis of the product.

Performance specific gravity of Takani Tadashi vacuum gas oil (15.6℃) 0.9248A
PI specific gravity (15.6℃) 21.5 pour point,'
C26,7 Aniline point, 'C75,0 Sulfur (LECO), wt% 2.24 Nitrogen (Kjeldahl), ppm 1100 Carbon, wt%
85.82 hydrogen, wt%
11.64 Bromine 5.0 Viscosity (98.9℃), CS T 6.954
Conradson carbon, test results with wt% of 0.42 or higher are summarized in Table ■. Catalysts 1-4 and 6 are derived from the materials of Part A of Example I. The data for these five catalysts shows that when the size of the zeolite unit cell is small, (1) the activity of the catalyst decreases, and (2) the selectivity increases. /490 5141544 82 99.0 Distillation.

P.B. 5/lO% 2fl/30 0150 60/70 80/90 P %Rec.

Which indicates that.

12”! Activity, 'F('C) Selectivity 1 774 (412) 59
1.502 778 (414)
59 1.133 786
(419) 61 0.6
54 797 (425) 63
0.145 782 (417)
60 1.306 782 (4
17) 59 1.257
761 (405) 55
2.608 782 (417)
56 2.18 This data also shows that catalysts Nα1-6 of the present invention are far superior in terms of overall activity and selectivity compared to catalysts NQ7 and 8, which contain untreated high acidity catalysts. ing. Catalyst Storm 1-6
Comparing Nα7 and Nα8, the zeolite component NH
It can be seen that excellent catalysts are obtained when the 3-TPO acidity strength is less than about 2.00. More specifically, catalyst Nn7 shows relatively high acidity (761"F/405°C) but low selectivity (55wt%). However, catalyst Nn7
The size of the unit cell of zeolite contained in is 24.56
4,401, cited above.
It should be noted that it does not fall within the preferred range of 24.20 to 24.45 of No. 556.

However, the zeolite unit cell size is 24.37 people, and the catalyst Nα8 in this range has the same activity (782 eF/
417°C), but the selectivity was poor (56 wt%).

From the above examples, it is clear that the NH3-TPD acidity strength of the zeolite component influences the overall performance of the hydrocracking catalyst.

As mentioned above, the zeolite feedstock for Part B is based on the previously cited prior art document, Bezman et al., U.S. Pat. No. 4,401.
, 556, among the many preferred zeolites described.

This means that the size of the unit cell subjected to hydrogenation treatment is 24.
This is a commercially available material from 37 people. One of the zeolites of the present invention included in the preferred materials of this document
The one exception is that the 0.
The ion exchange capacity is 171. This material is catalyst 8
It was used in The Bez-man reference teaches that the ion exchange capacity should not exceed 0.07.

The dry calcination of the present invention converts the material used in catalyst 8 into the material used in the preparation of catalyst 5. Catalyst 5 has good selectivity even with the same activity, and is an excellent catalyst. However, the difference in unit cell size between catalysts 5 and 8 is of little significance. The method of the invention therefore improves the selectivity of the catalyst by a much greater factor than would be expected by varying the unit cell size. Zeolite E used in Superior Catalyst 5 has an ion exchange capacity of 0.091. This exceeds the upper limit of Bexman et al. by 28%.

Claims (1)

[Claims] 1. A hydrocarbon feedstock stream is subjected to hydrogen cracking to produce a heat-resistant inorganic oxide matrix and a hydrogen type Y-type zeolite with a unit cell size of 24.20 to 24.40 Å as a main component. A process for the hydrocracking of middle distillates having a boiling point of 149 DEG to 371 DEG C., in which the zeolite has an ion exchange capacity greater than 0.07 and less than 2.00. NH_3-T
A process for the hydrocracking production of middle distillates, characterized in that a low acidity zeolite having a content of bound hydroxyls low enough to give PD acidity strength is used. 2. A hydrocarbon feed stream containing at least 50% by volume of components with a boiling point of 371° C. or higher is mixed into (i) a hydrogenation component, (ii) a heat-resistant inorganic oxide matrix mainly composed of alumina, and (iii) a unit cell. The size is 24.20-24.40 Å, the ion exchange capacity is greater than 0.07, and NH_3-TPD
contact with a catalyst composition comprising a crystalline hydrogen Y-type aluminosilicate zeolite having an acidity strength of less than 1.50 and maintained at hydrocracking conditions, and then recovering the product stream. Hydrocracking selective production method for intermediate barrel fractions. 3. The method of claim 2, wherein said composition comprises 2 to 20 wt% of said zeolite. 4. The method of claim 2, wherein the heat-resistant inorganic oxide matrix is mainly a mixture of alumina and silica-alumina. 5. The method of claim 2, wherein the base material is mainly composed of 45 to 90 wt% silica-alumina and 5 to 45 wt% alumina. 6. The method of claim 2, wherein said hydrogenation component is selected from Group VIB metals, Group VIII metals, and combinations thereof. 7. The method of claim 2, wherein the Group VIB component is selected from the group consisting of molybdenum, tungsten and compounds thereof, and the Group VIII metal component is selected from the group consisting of nickel, cobalt and compounds thereof. 8. (i) a hydrogenated component, (ii) a heat-resistant inorganic oxide matrix based on alumina, and (iii) an X-ray powder diffraction pattern essentially of zeolite Y, with an ion exchange capacity of 0.07 larger, unit cell size is 24.20 ~
24.40 Å, and a crystalline hydrogen aluminosilicate having an NH_3-TPD acidity strength of less than 1.50. A selective hydrogen cracking catalyst composition for producing middle distillates.