KR20140034177A - Novel process and catalyst system for improving dewaxing catalyst stability and lubricant oil yield - Google Patents

Abstract

The present invention provides a method of dewaxing a waxy hydrocarbon feedstock to form lubricating oil. The invention also relates to a catalyst system comprising a hydrotreating catalyst upstream of a dewaxing catalyst for use in dewaxing waxy hydrocarbon feedstocks that form lubricating oil. In particular, the present invention relates to methods and catalyst systems designed to maintain yields of lubricating oil products. Specifically, the yield of lubricating oil does not decrease by more than 2% at the target pour point over the dewaxing temperature range. The hydrotreating catalyst prevents aging of the dewaxing catalyst at the target pour point over a wide temperature range and maintains the yield of lubricating oil product. Hydrotreating catalysts include platinum, palladium, or combinations thereof, on low acidity inorganic oxide supports whose acidity is measured at a decalin conversion of less than 10% at 700 ° F.

Description

NOVEL PROCESS AND CATALYST SYSTEM FOR IMPROVING DEWAXING CATALYST STABILITY AND LUBRICANT OIL YIELD

The present invention relates to a method for reducing the wax content of a hydrocarbon feedstock containing wax. In particular, the present invention relates to a process for converting a wax-containing hydrocarbon feedstock into a higher product comprising a lubricant base oil having a low pour point. The process uses a layered catalyst system comprising a hydrotreating catalyst and a dewaxing catalyst, wherein the aging rate of the dewaxing catalyst is slowed down and the base oil product is about 450 ° F. In the temperature range from 725 ° F.

Many hydrocarbon feedstocks contain relatively high concentrations of aliphatic compounds in the form of straight chains and lightly branched chains having from 8 to 40 carbon atoms. These compounds tend to form solid waxes upon cooling of the hydrocarbon feedstock. The temperature at which hydrocarbon oil does not flow is often referred to as the "pour point". Wax forming compounds are generally removed or converted through distillation or hydrotreating processes such as hydrocracking and hydroisomerization. Hydrocracking decomposes high molecular weight hydrocarbon components into low molecular weight components in the presence of hydrogen. In the dewaxing and / or diesel dewaxing process of lubricant base oils, hydrocracking reactions reduce the waxy content of the feedstock, but can yield lower molecular weight hydrocarbons such as heavy oils and lighter C4-products to reduce yields. . Hydroisomerization is another approach to reducing the wax content of the feedstock, which results in the formation of highly cracked, low molecular weight products to minimize loss of yield. Hydroisomerization converts aliphatic unbranched paraffinic hydrocarbons into iso-paraffins and cyclic species that do not easily form waxes.

Hydroisomerization is well known in lubricant base oil dewaxing processes. For example, US Pat. No. 4,222,543 and US Pat. No. 4,814,543 disclose and claim the use of limited intermediate-pore molecular sieves for lubricant dewaxing. U.S. Patent 4,283,271 and U.S. Patent 4,283,272 claim the use of these catalysts for dewaxing hydrocrackates in energy efficient batches. U. S. Patent No. 5,135, 638, U. S. Patent No. 5,246, 566 and U. S. Patent No. 5,282, 958 also relate to a process for dewaxing with limited meso-pore molecular sieves. U.S. Patent No. 4,347,121 claims a process for catalytic dewaxing of hydrocrackates comprising less than 10 ppm nitrogen in a hydrofinishing step upstream of the dewaxing catalyst. Particularly with regard to dewaxing of lubricant base oils, minimizing catalyst aging and maximizing yield are one of the important considerations for an efficient dewaxing process.

Various processes have been attempted to minimize aging of the catalyst. For example, US Pat. No. 5,456,820 discloses a process in which a lube boiling range feedstock is dewaxed by a catalytic reaction with a catalyst comprising a de-ionized form of mesoporous zeolite in the presence of hydrogen. Doing. The catalyst cycle length has been found to be improved by optimizing the sequencing of various solvent extraction feedstocks. In addition, multi-layered catalyst systems have been described in a manner that minimizes aging of the dewaxing catalyst. U.S. Patent Nos. 5,951,848 and WO 98/02503 disclose the use of two catalyst systems comprising a hydrotreating catalyst and a dewaxing catalyst. The hydrotreating catalyst layer is also referred to as "guard bed" or "guard layer". Aging of the dewaxing catalyst is slowed down by the presence of a guard layer or hydrotreating catalyst layer that protects the dewaxing catalyst from contact with a high aromatic feedstock that deactivates the dewaxing catalyst. US Pat. No. 4,749,467 discloses a method for extending the dewaxing catalyst cycle length using a combination of low space velocity and high acidity meso-porous zeolites. High acid activity and low space velocity reduce the cycle start temperature. Since the catalyst deactivation reaction is more temperature sensitive than the dewaxing reaction, lower operating temperatures reduce the aging rate of the catalyst. As such, it is known that it is important to reduce the aging of the dewaxing catalyst, and this has been done through the use of multilayer catalyst systems or guard bed systems, but conventional guard bed catalyst systems process at temperatures above about 600 ° F. It has been found that the formation of middle distillate and low molecular weight products reduces the base oil production rate of the lubricant dewaxing process. Minimizing yield loss is particularly economically important for the production of lubricant base oils. Thus, a lubricant dewaxing method that protects the dewaxing catalyst from aging and minimizes yield loss of lubricant base oils even at temperatures above about 600 ° F. is highly desirable. Accordingly, the present inventors have found that by strictly controlling the acidity of the hydrotreating catalyst upstream of the dewaxing catalyst, it is possible to maintain the yield of lubricating oil over a wide range of temperatures for the target pour point.

The present invention is a method of producing a lubricant by dewaxing a waxy hydrocarbon feedstock by catalytic reaction,

a) contacting the waxy hydrocarbon feedstock in the first reaction zone with a hydrotreating catalyst under hydrotreating conditions in which the aromatics content of the feedstock is reduced to form a first effluent; And

b) in a second reaction zone, contacting at least a portion of the first effluent with a dewaxing catalyst under dewaxing conditions to produce a lubricating oil having a pour point lower than the pour point of the first effluent,

The hydrotreating catalyst is

Iii) a Group VIII metal supported on an inorganic oxide support;

Ii) exhibit a decalin conversion of less than 10% at 700 ° F .;

Iii) less than 0.25 meq of acid sites per gram of said catalyst.

In a preferred embodiment of the process of the invention, the hydrotreating and dewaxing catalysts are in the same reactor. In another embodiment, the hydrotreating catalyst and the dewaxing catalyst are in separate reactors from each other that do not treat fluid therebetween.

In one embodiment, the present invention is a layered catalyst system,

a) a hydrotreating catalyst comprising a Group VIII metal supported on an inorganic oxide support and exhibiting a decalin conversion of less than 10% at 700 ° F .; And

b) a dewaxing catalyst comprising an acid component and a Group VIII metal selected from the group consisting of zeolites, zeolite analogs, non-zeolitic molecular sieves, acidic clays and combinations thereof;

The hydrotreating catalyst and the dewaxing catalyst relate to a layered catalyst system present in a ratio of about 1:20 to about 1: 2.

In one embodiment, the dewaxing catalyst comprises a Group VIII metal and an acidic component that acts as a hydrogenation component. In one embodiment, the Group VIII metal is platinum, palladium or a combination thereof. In one embodiment, the acidic component is selected from the group consisting of zeolites, zeolite analogues, non-zeolitic molecular sieves, acidic clays, and combinations thereof. Generally, the hydrotreating catalyst and the dewaxing catalyst are present in a ratio of about 1:20 to about 1: 2, preferably about 1:20 to 1: 6.

The advantage of the system of the present invention over conventional catalyst systems is that it can maintain high lubricating oil yield over a wider temperature range. Without being bound by any theory, the inventors believe that minimizing or eliminating the acid sites of the hydrotreating catalyst to maximize lubricating oil yield while preventing the hydrocracking of the feedstock at elevated temperatures while efficiently hydrogenating the aromatic species. As the dewaxing catalyst is aging, the reactor is run at higher temperatures to maintain the target pour point of the product. Conventional dewaxing reactors are run at about 550 ° F to 750 ° F. At temperatures above about 600 ° F., hydrocracking with conventional hydrotreating catalysts reduces lubricating oil yield, through unwanted hydrocracking and / or dealkylation reactions, which are more preferred at higher temperatures. We have found that hydrotreating catalysts with a decalin conversion of less than about 10% at 700 ° F. upstream of the dewaxing catalyst reduce the dewaxing catalyst aging without reducing the overall lubricating oil yield above 2% at the target pour point. .

The process of the present invention includes the step of contacting a hydrocarbon feedstock with a catalyst system comprising a hydrotreating catalyst and a dewaxing catalyst. The invention also relates to a catalyst system comprising a hydrotreating catalyst and a dewaxing catalyst. The “hydrogenation catalyst” refers to contacting aromatic species in a waxy hydrocarbon feedstock that can inactivate (ie, age) the dewaxing catalyst to prevent early aging of the dewaxing catalyst or to protect the dewaxing catalyst from early aging. In this respect, it may be referred to as a "guard layer". Preferably, the process of the present invention is carried out in a single reactor system in which the reaction conditions are determined by the temperature required by the dewaxing catalyst to reach the lubricating oil pour point target. Therefore, the actual temperature of the upstream hydrotreating catalyst is slightly lower than or equal to the temperature described in the dewaxing catalyst requirement. Conventional dewaxing catalysts carry out the reaction at operating temperatures of about 550 ° F. to about 750 ° F. Actual process conditions depend on various factors such as feed wax, feed nitrogen content, feed boiling range, LHSV, operating pressure, dewaxing catalyst formulation, and catalyst activity and lifetime.

While testing the concept of layered catalysts for specific dewaxing processes, ie the production of lubricating oil from waxy feedstock, it has been found that the nature of the hydrotreating catalyst or guard layer used is important to maintain high lubricating oil yield. When using a conventional Pt / Pd catalyst on a silica-alumina base as a guard layer of the catalyst system, the system yield is increased or at least preserved at operating temperatures up to 600 ° F. and above that part of the lubricating oil product. It has been found that the cracks are broken down into diesel and kerosene, resulting in a loss of lubricating oil product yield. It is an object of the present invention to produce the hydrotreating catalyst upstream of the dewaxing catalyst to produce even at temperatures in excess of about 600 ° F. through the use of a novel catalyst system that minimizes undesirable decomposition of the waxy hydrocarbon feedstock. It is to maintain the yield of lubricating oil. The acidity of the hydrotreating catalyst can be deduced from measurements of decalin conversion at 700 ° F. The hydrotreating catalyst used in the process and the catalyst system of the present invention are less than about 10%, preferably less than about 8%, more preferably less than about 6%, and most preferably less than about 4% decalin at 700 ° F. Has a conversion rate.

Justice

Although the present invention may be in various modifications and alternative forms, specific embodiments thereof are described in detail herein. However, the detailed description herein of particular embodiments should not be construed as limiting the invention to the specific forms disclosed, on the contrary, the intention being that all modifications falling within the spirit and scope of the invention as defined by the claims, It should be understood to encompass equivalents and alternatives.

As used herein, the following terms have the following meanings unless indicated otherwise.

As used herein, "hydrotreating" includes but is not limited to hydrodesulphurization, hydrodenitrogenation, hydrodemetallization, hydrodearomatization and hydrogenation of unsaturated compounds. Any method carried out in the presence of hydrogen to remove or reduce impurities. Depending on the type of hydrotreating and the reaction conditions, the products of hydrotreating can exhibit, for example, improved viscosity, viscosity index, saturate content, low temperature properties, volatility and depolarization.

As used herein, "guard bed" or "guard layer" means a hydrotreating catalyst or hydrotreating catalyst layer immediately upstream of the dewaxing catalyst.

As used herein, the term “molecular sieve” includes uniformly sized pores, pores or gap spaces in which molecules small enough to pass through the pores, pores or gap spaces are adsorbed and larger molecules are not adsorbed. Means crystalline material. Examples of molecular sieves include zeolites such as, but not limited to, zeolite analogs including, but not limited to, SAPO (silicoaluminophosphate), MeAPO (metalloaluminophosphate), AlPO ₄ and ELAPO (nonmetal substituted aluminophosphate family) And non-zeolitic molecular sieves.

"Target pour point" means the desired pour point of the lubricant base oil product. The target pour point is generally below -10 ° C, preferably in the range of -10 ° C to -50 ° C, most preferably in the range of -10 ° C to -30 ° C. In one embodiment, the target pour point can be up to -30 ° C.

Unless otherwise stated, 100% yield of lubricating oil means the amount of lubricating oil produced without a guard layer upstream of the dewaxing layer. The amount of lubricating oil produced (by weight) produced at the target pour point for a given feed running only above the dewaxing catalyst under dewaxing conditions, and above the catalyst system of the present invention (i.e. guard layer upstream of the dewaxing bed) Yield of the lubricating oil produced at the target pour point for a given feed that subtracts the amount of lubricant produced (by weight) while running the feed under the same dewaxing conditions at the same target pour point, and runs only above the dewaxing catalyst under the dewaxing conditions. Divide by (by weight) to calculate the change in lubricant yield. For example, as used herein, the formula (A-B) / A can be used to calculate the change in lubricant yield. "A" means the weight of lubricating oil produced at the target pour point from a given feed on the dewaxing catalyst, and "B" is produced at the target pour point from the feed on a catalyst system comprising a hydrotreating catalyst upstream of the dewaxing catalyst. Means the weight of the lubricating oil. For example, "the lubricating oil yield does not decrease by more than 2% over the dewaxing temperature range at the target pour point." Upstream of the dewaxing catalyst, the lubricating oil yield for the hydrotreating catalyst is the same temperature for the same target pour point. This means that when run only on the dewaxing catalyst, it can be less than 2% by weight of lubricating oil yield.

As used herein, the term “large pore zeolite” means a zeolite having pore features in the range of about 0.7 nm to about 2.0 nm in diameter. Examples of “air pore zeolites” include, but are not limited to, zeolites Y, FAU, EMT, ITQ-21, ITQ-33, and ERT.

As used herein, the term “medium pore zeolite” means a zeolite having pore features in the range of about 0.39 nm to about 0.7 nm in diameter. Examples of mesoporous zeolites include, but are not limited to, ferrierite, steel bite, SAPO-11, ZSM-5, SSZ-32, ZSM-48 and ZSM-23.

As used in this disclosure, the elemental periodic table mentioned is a CAS version published by Chemical Abstract Service in Handbook of Chemistry and Physics, 72 ^nd edition (1991-1992).

“Group VIII metals” is an elemental metal and / or metal compound comprising a metal selected from the periodic table published by the Chemical Abstracts Service in the Handbook of Chemistry and Physics, 72 ^nd edition (1991-1992), a group of CAS versions Means.

Unless stated otherwise, the “feed rate” for the catalytic reaction zone is reported in feed volumes per catalyst volume per hour. The feed rate disclosed herein is recorded as the inverse of time (ie, time ⁻¹ ), also referred to as Liquid Hourly Space Velocity (LHSV).

Supply

The process of the invention can be carried out with a wide variety of feedstocks. Hydrocarbon feedstocks that can be treated in accordance with the present invention include oils with generally high pour points (pour points above about 0 ° C.), which are desirable to lower pour points. In one embodiment, the hydrocarbon feedstock may be described as waxy feeds, and the waxy is that the feedstock is very viscous due to the presence of n-paraffins to solidify, precipitate or form solid particulates. I mean.

Preferably, the feedstock used in the process of the present invention is generally boiling in the range of 500 ° F. to 1300 ° F. and having a kinematic viscosity of greater than about 3 cSt (as measured at 100 ° C.). Suitable hydrocarbon feedstocks for use in the process of the present invention are, for example, crude oil, petroleum distillates having a common boiling point above about 100 ° C., light oil and vacuum gas oil, residue fractions obtained from atmospheric distillation processes, solvent deasphalted petroleum residues And shale oils, circulating oils, animal and vegetable derived fats, waxes and oils, petroleum and crudes, waxy petroleum feedstocks, NAO waxes and waxes prepared in chemical plant processes. Straight chain n-paraffins are often referred to herein as waxes, either alone or with only slightly branched branched paraffins having 16 or more carbon atoms. Preferred petroleum distillates boil in the boiling range of about 200 ° C. to about 700 ° C., more preferably in the boiling range of about 260 ° C. to about 650 ° C. Suitable feedstocks include heavy distillates and fed conventional FCC feeds, and portions thereof, which are typically defined as heavy dc light oil and heavy cracked circulating oil. Decomposed stock can be obtained from heat or catalytic cracking of various stocks. The feedstock may be provided to the process of the invention after being treated by hydrotreating and / or hydrocracking processes. Alternatively or in addition, the feedstock may be used in the process of the invention after it has been treated in a solvent extraction process to reduce aromatics and sulfur and nitrogen containing molecules.

Preferably, the hydrocarbon feedstock treated in accordance with the present invention generally has an initial pour point above about 0 ° C., more generally above about 20 ° C. In one embodiment, the feedstock has a pour point greater than about 50 ° C. The hydrocarbon product produced after completion of the process of the present invention generally has a pour point corresponding to less than 0 ° C., more preferably less than about −10 ° C., and most preferably less than about −15 ° C.

The term "waxy hydrocarbon feedstocks" as used herein includes petroleum waxes, plant waxes and animal derived waxes. The feedstock used in the process of the invention may be a waxy feed comprising more than about 50% wax, even more than about 70% wax. Preferably, the feed comprises about 5% to about 30% wax.

Examples of further feeds suitable for use in the process of the invention include waxy distillate stocks, such as diesel oil, lubricant stocks, synthetic oils and waxes such as by Fischer-Tropsch synthesis, high pour point polyalpha. Olefins, foot oils, synthetic waxes such as alphaolefin waxes, crudes, deoiled waxes and microcrystalline waxes. The oil is separated from the wax to produce a foot oil. The process of the present invention can be practiced using various feeds of mineral oil origin to produce a wide range of lubricant base oils with good performance characteristics. These properties include low pour point, low cloud point and high viscosity index. The quality of the base oil stock and the dewaxing yield depend on the quality of the feedstock and its adaptability to the process with the catalyst of the invention. The feedstock for the process is derived from atmospheric resid fractions of crude oil, including vacuum gas oil and vacuum residues, and those prepared by Fischer-Tropsch processing of syngas. Preferably, the hydrocarbon feedstock used in the process of the present invention has less than about 10 ppm nitrogen, more preferably less than about 2 ppm nitrogen. Any petroleum stream useful for the production of lubricating oils can be used as hydrocarbon feedstock in the process of the invention.

One or more pretreatment steps may be performed on the feedstock to reduce the heteroatoms, aromatics, asphaltenes and polycyclic naphthenic content of the feed. This upgrading step can be carried out by solvent extraction, hydrotreating or a combination of the two steps. Since nitrogen and sulfur act as poisons to the noble metal containing catalyst, the preferred feedstock for the present invention is to be hydrotreated. However, some solvent purified raffinates are also suitable for dewaxing with the catalyst of the present invention.

As above, the hydrocarbon feedstock may be pretreated by hydrocracking prior to the process of the present invention. Hydrocracking processes typically include reaction temperatures ranging from 250 ° C. to 500 ° C., pressures ranging from 30 to 205 bar or greater, hydrogen recycling rates from 2000 to 20000 standard cubic feet perbarrel (SCF / B) and 0.1 to 10 LHSV (v / v time). Hydrocracking catalysts well known in hydrotreating techniques typically include one or more metals or compounds thereof selected from Groups VIB and VIII of the Periodic Table. Hydrocracking catalysts also typically comprise refractory inorganic oxides such as silica, alumina, silica-alumina, silica-alumina-zirconia and silica-alumina-titania complexes, acid treatment clays, and combinations thereof, and optionally also crystalline. Aluminosilicate zeolite molecular sieves (eg, zeolite A, faujasite, zeolite X and zeolite Y).

Hydrotreating Catalyst

The catalyst system of the present invention preferably comprises a hydrotreating catalyst acting as a guard layer and a dewaxing catalyst in the same reactor, the hydrotreating catalyst being immediately upstream of the dewaxing catalyst. In one embodiment, the hydrotreating catalyst and the dewaxing catalyst are at the same temperature. In further embodiments, the hydrotreating catalyst is a high activity catalyst. By “high activity” is meant that the hydrotreating catalyst can be effectively operated at high liquid space-time rates (LHSV above about 1.0 hour ⁻¹ ) over a temperature ranging from about 550 ° F. to about 750 ° F. In a preferred embodiment, the hydrotreating catalyst is in the same reactor as the dewaxing catalyst. When the hydrotreating catalyst and the dewaxing catalyst are in the same reactor, the hydrotreating catalyst comprises from about 5% to about 30% by volume of the total catalyst in the reactor. The total catalyst volume can be described as the sum of the volume of the hydrotreating catalyst and the volume of the dewaxing catalyst. Preferably, the hydrotreating catalyst comprises about 10% to about 15% of the total catalyst volume. When in the same reactor as the hydrotreating catalyst, the dewaxing catalyst constitutes from about 75% to about 95% of the total catalyst, preferably from about 85% to about 90% of the total catalyst volume.

The hydrotreating catalyst of the present invention comprises a Group VIII metal, preferably platinum, palladium or a combination thereof, dispersed on a low acidity inorganic oxide support. In a preferred embodiment, the ratio of platinum to palladium is from about 5: 1 to about 1: 5. In another embodiment, the hydrotreating catalyst comprises a platinum-palladium alloy and the molar ratio of platinum to palladium in the alloy is about 3: 1 to about 1: 3, preferably about 2: 1 to about 1: 2. The amount of platinum and / or palladium metal present in the catalyst may range from 0.01% to 5% by weight, preferably from 0.2% to 2% by weight. The amount of platinum-palladium alloy located in the support should be sufficient to serve as an effective catalyst in the hydrogenation of the hydrocarbon feedstock. In general, the addition of more than about 1% by weight of the alloy does not significantly improve the activity of the catalyst and is therefore economically disadvantageous. However, amounts greater than 1% by weight are generally not detrimental to the performance of the catalyst. Preferred hydrotreating catalysts exhibit the activity of palladium-based catalysts while maintaining the sulfur tolerance of the less reactive platinum-based catalysts, thus providing a hydrogenation catalyst having good activity over a wide temperature range.

Numerous methods are known in the art for depositing platinum and palladium metals or compounds, including platinum and / or palladium, on supports such as ion exchange, impregnation and coprecipitation, and the like. In one embodiment, the impregnation of platinum and / or palladium metal is carried out under controlled pH. In another embodiment, the impregnation solution may be buffered to maintain the pH in the range of about 9 to about 10. In further embodiments, the impregnation of the platinum and / or palladium metal is performed at an acidic pH (ie, below pH 7). In another embodiment, the impregnation of platinum and / or palladium metal is performed at basic pH (ie, above pH 7). Any pH value may be used to deposit platinum and / or palladium metal on the support, with the exception that platinum and / or palladium should be dispersed in the support to produce a catalyst capable of hydrogenating aromatic species in the feedstock. Platinum and / or palladium metals are generally added to the impregnation solution as metal salts such as halide salts and / or amine complexes and / or mineral salts. Ammonium salts have been found to be particularly useful when preparing the impregnation solution. Representative examples of metal salts that can be used include nitrates, carbonates, bicarbonates and carboxylates such as acetates, citrates and formates. In the case of palladium, ammonium nitrate salts or chloride salts have been found to produce successful results. However, other salts of platinum group metals are also applicable and can be used to impregnate the support. In such cases, it may be useful to determine the optimum pH for use during impregnation with the particular salt selected to obtain the optimal metal distribution on the support.

After impregnation, the impregnated support may be dried and / or calcined. Optionally, the impregnated support is left to stand and dried for a time sufficient to achieve equilibrium with the impregnation solution. In the case of extrudates, this period is generally at least 2 hours, with periods up to 24 hours not harmful to the final catalyst. For example, by measuring drying and metal distribution at various times after impregnation, one skilled in the art can easily determine a settling time suitable for a given support. After optionally standing, the catalyst is dried, calcined, dried and calcined. The produced catalyst can also be reduced and serviced with hydrogen as is customary in the art.

Hydrotreating catalysts used in the present invention include catalyst supports generally prepared from alumina, silica, silica / alumina, titania, magnesia, zirconia or combinations thereof in addition to the Group VIII metals. The catalyst support may comprise an amorphous material, a crystalline material or a combination thereof. Examples of amorphous materials include, but are not limited to, amorphous alumina, amorphous silica, amorphous silica-alumina, and the like. In a preferred embodiment, the support is amorphous alumina. When using a combination of silica and alumina, the distribution of silica and alumina in the support may be homogeneous or heterogeneous. For example, a uniform distribution is usually obtained when the silica / alumina ratio is uniform across the support resulting from conventional coprecipitation or cogelation techniques. In some embodiments, the support consists of an alumina gel in which silica, silica / alumina or alumina based materials are dispersed. Alumina gels are also referred to as "oxide binders". The support may also comprise refractory materials such as inorganic oxides or clay particles other than alumina or silica, provided that these materials do not negatively affect the hydrogenation activity of the final catalyst or due to the presence of too many acid sites Should not cause harmful decomposition. Generally, silica and / or alumina constitute at least 90% by weight of the total support, and most preferably the support is substantially all silica and / or alumina. The support may comprise acidic protons which can cause deleterious decomposition reactions. In general, alkali and / or alkaline earth cations may be used to neutralize acidic protons in the support. Sodium and potassium cations are preferably used to neutralize acidic protons. By replacing some or all of the acidic protons with non-acidic cations, the acidity of the support can be reduced.

The catalyst support may include crystalline materials, including but not limited to zeolites, zeolite analogs, molecular sieves, silicoaluminophosphates and metalloaluminophosphates. In total, crystalline inorganic oxides useful in the process of the invention are referred to herein as "molecular sieves". By "zeolite analogue" is meant that some of the silicon and / or aluminum atoms in the zeolite are replaced by other quaternary atoms such as germanium, boron, titanium, phosphorus, gallium, zinc, iron or mixtures thereof. As used herein, the term "non-zeolitic molecular sieve" refers to a molecular sieve in which the framework is substantially not formed solely of silicon and aluminum atoms that are coordinating with oxygen atoms.

Zeolite, zeolite analog of non-zeolitic molecular sieve is a crystalline having a three-dimensional structure, broadly consisting of tetrahedral units _{(TO 4/2, T =} Si, Al , or another four coordinating atoms) is connected via an oxygen atom micro-porous molecular sieve Can be described. The pores in the molecular sieve are usually classified into small pores (8 T atoms), mesopores (10 T atoms), and atmospheric pores (more than 12 T atoms), depending on the number of tetrahedral atoms surrounding the pore features. Zeolite A (LTA) and Zeolite Rho are examples of molecular sieves with small pores defined by an 8-membered ring whose pore features are measured from about 3 to 4.4 kPa, while ZSM-5, ZSM-11, ferrierite are pores Examples of mesoporous 10-membered rings with an aperture measuring from about 3.9 to 6.5 kPa, zeolite X, zeolite Y, and zeolite beta have atmospheric pores defined by 12-membered rings with pore features measuring greater than about 6.5 kPa Example of zeolite. In addition to the pore features, molecular sieves have internal channels. The classification of channels in zeolites as one-dimensional, two-dimensional or three-dimensional is described in RMbarrer in Zeolites, Science and Technology, edited by FR Rodrigues, LD Rollman and C. Naccache, NATO ASI Series, 1984. Is incorporated by reference in its entirety (see page 75 in particular).

Depending on the identity of the T atoms in the zeolite, zeolite analogues or non-zeolitic molecular sieves, the properties of the material are affected. For example, the presence of aluminum in the zeolite introduces a negative charge in the zeolite structure and affects the acidity of the zeolite. The Si / Al ratio in the zeolite can vary from about 1 to infinity. The lower limit is tetrahedral units and an adjacent negative charges arise from the avoidance of ^{(Al - - -O-Al)} . It is generally recognized that the connection of two AlO ₄ tetrahedra is sufficiently inadequate for energy to make this impossible. The negative charge in the zeolite, zeolite analogues or non-zeolitic molecular sieve structures is compensated by superstructure cations such as protons and alkali cations. The presence of superstructure protons results in the acidity of the molecular sieve. The support of the hydrotreating catalyst may comprise the molecular sieves described above, provided that the acid sites of the molecular sieves are for example neutralized with alkali or alkaline earth cations. In general, acidic protons in the molecular sieve can be ion exchanged with non-acidic cations such as sodium or potassium cations.

The hydrotreating catalyst support may comprise a layered material such as clay (natural or synthetic). Clay may be described as phyllosilicate in which the sheet of silicon ions is coordinated and the sheet of metal ions is coordinated and / or quadrupled by oxygen atoms. The clay may be acidic due to the introduction of protons into the gap spaces between the clay structures or layers. Acidic protons can be replaced by non-acidic cations such as sodium, potassium, magnesium and the like. By replacing some or all of the acidic protons with non-acidic cations, the acidity of the clay can be reduced.

Regardless of the type of support material in the hydrotreating catalyst, the hydrotreating catalyst used in the process and the catalyst system of the present invention have low acidity. "Low acidity" refers to Bronsted and / or Lewis acid sites with or without Brønsted and / or Lewis acid sites, or for Brønsted pH, for example by ion exchange of acidic protons to non-acidic cations. This means that Lewis's site is neutralized. For example, to reduce acidity, the molecular sieve preferably comprises an alkali metal and / or an alkaline earth metal when present as a support or component of the support in the hydrotreating catalyst. Alkali or alkaline earth metals are incorporated into the catalyst support during or after the synthesis of the hydrotreating catalyst. Preferably, at least 90%, more preferably at least 95%, most preferably at least 99% of the acid sites in the catalyst support are neutralized by the introduction of non-acidic cations.

e, et.al., Infrared and Temperature-Programmed Desorption Study of the Acidic Properties of ZSM-5-Type Zeolites, J. Catalysis 70, 41-52 (1981)]은 산 유형 촉매를 연구하기 위한 적외선(IR) 방법을 기술하고 있다. 통상적으로, 약 400℉에서 수소 1대기압에서 환원되는 최종 촉매를 사용하여 산 자리 밀도를 측정한다. 유용한 IR 방법은 500℃에서 진공(약 10^-6torr) 하의 자가 지지 웨이퍼 형태의 촉매 샘플을 가열하여 촉매로부터 휘발물, 특히 물을 제거하는 것을 포함한다. 촉매 샘플을 450℃에서 12시간 동안 유지시키고 이후 150℃로 냉각한다. 이후, 촉매 샘플에 활성화 린데(Linde) 5A 분자체 위에서 이미 건조된 (대략 1torr 압력에서의) 공지량의 피리딘 증기를 넣고 종래의 냉동 펌프 해동 기술을 이용하여 탈기한다. 예를 들면, 니콜레트(Nicolet) 60SXR 푸리에 변환 적외선(FT-IR) 분광기를 사용하여 샘플로부터 적외선 스펙트럼을 취한다. 1453㎝^-1 및 1543㎝^-1 밴드 하의 면적은 촉매 표면에서의 양성자 (브뢴스테드) 산 자리 밀도 및 비양성자 (루이스) 산 자리 밀도의 측정치를 생성시킨다. 피리딘으로 포화된 촉매 샘플을 수증기로 추가로 포화시키고, 적외선 스펙트럼을 다시 스캔한다. 수증기 첨가는 브뢴스테드/루이스 산 자리 밀도의 비를 이동시킨다. 2개의 적외선 스캔의 피크 면적은 브뢴스테드 및 루이스 산 자리에 흡착된 피리딘의 양을 계산하는 데 충분한 상세내용을 제공한다. 전체 산 자리 밀도는 루이스 및 브뢴스테드 산의 자리 밀도의 합이다.
The number and concentration of potential acid sites can be determined by any of a number of methods known in the art. See, for example, N. Tops

e, et. al., Infrared and Temperature-Programmed Desorption Study of the Acidic Properties of ZSM-5-Type Zeolites, J. Catalysis 70, 41-52 (1981)]. The method is described. Typically, the acid site density is measured using a final catalyst that is reduced at 1 atmosphere of hydrogen at about 400 ° F. Useful IR methods include heating the catalyst sample in the form of a self-supporting wafer at 500 ° C. under vacuum (about 10 ⁻⁶ torr) to remove volatiles, especially water, from the catalyst. The catalyst sample is held at 450 ° C. for 12 hours and then cooled to 150 ° C. The catalyst sample is then charged with a known amount of pyridine vapor (at approximately 1 Torr pressure) already dried over an activated Linde 5A molecular sieve and degassed using conventional refrigeration pump thawing techniques. For example, an infrared spectrum is taken from a sample using a Nicolet 60SXR Fourier Transform Infrared (FT-IR) spectrometer. The areas under the 1453 cm ^-1 and 1543 cm ^-1 bands produce measurements of the proton (Brooksted) acid site density and the aprotic (Lewis) acid site density at the catalyst surface. The sample of catalyst saturated with pyridine is further saturated with water vapor and the infrared spectrum is scanned again. Steam addition shifts the ratio of Bronsted / Lewis acid site density. The peak areas of the two infrared scans provide enough detail to calculate the amount of pyridine adsorbed at the Bronsted and Lewis acid sites. The total acid site density is the sum of the site densities of Lewis and Bronsted acids.

Another method of measuring the acidity of the catalyst or catalyst support is ammonia adsorption / desorption. For example, ammonia or other nitrogen bases are adsorbed on the catalyst. For example, the weight of the catalyst can be weighed before and after ammonia adsorption to determine the total ammonia adsorbed. The adsorbed ammonia can then be desorbed by heating the sample step by step and monitoring the desorption by mass transfer. The method can provide estimates of acid sites and concentrations of acid sites present in the catalyst (due to ease or difficulty in desorbing ammonia).

The technique for determining the catalyst acidity measures the number of acid sites in units of milliequivalents (meq) per gram of catalyst. As used herein, "milliequivalent weight" means 1 millimolar of Lewis or Bronsted acid sites. The amount of base adsorbed is related to the acid site density and the number of acid sites that each adsorbent molecule adsorbs. The acid site density of the catalyst of 1 meq / gm is an equivalent having 1 millimolar of base adsorbed to 1 gram of catalyst when each molecule of the base adsorbs to a single acid site. Preferably the hydrotreating catalyst used in the process of the invention comprises less than 0.25 meq / g, more preferably less than 0.15 meq / g, most preferably less than 0.1 meq / g.

Decalin conversion at 700 ° F. is used to determine if the hydrotreating catalyst is used in the process and catalyst system of the present invention. "Decalin conversion" means the decomposition of decalin, which results in a lower molecular weight product. We have found that hydrotreating catalysts having a decalin conversion at 700 ° F. of less than about 10% can be used in the process and catalyst system of the present invention. Decalin conversion is an indirect measure of the acidity of a hydrotreating catalyst. In general, lower decalin conversion results in lower catalytic acidity and thus less detrimental feedstock degradation.

The pore size distribution and pore volume of the hydrotreating catalyst can vary. The pores can be macroporous, mesoporous or a combination thereof. The term "macroporosity" as used herein, means a catalyst having more than 5% of pores greater than about 100 nm in diameter, as measured by mercury porosimetry. As used herein, the term "mesoporous" refers to a catalyst having greater than 95% porosity of less than 100 nm in diameter, as measured by mercury porosimetry. Preferably, the hydrotreating catalyst has a relatively large pore volume greater than about 0.1 cm 3 / g, more preferably greater than about 0.2 cm 3 / g, most preferably greater than about 0.3 cm 3 / g with mesopores and / or macropores. It includes a support having. For example, the pore size distribution for the catalyst used in the present invention is determined using the mercury intrusion porosimetry described in ASTM D4284, "Pore Volume Distribution of Catalysts by Mercury Intrusion Porosimetry."

Reaction conditions

The hydrogenation reaction carried out on the hydrotreating catalyst takes place in the presence of hydrogen, preferably at a hydrogen pressure in the range from about 500 psia to 4000 psia, more preferably in the range from about 900 psia to about 3000 psia. The feed rate to the hydrotreating catalyst is LHSV in the range of about 3 to about 50, preferably LHSV in the range of about 5 to about 15 when the hydrotreating catalyst is in the same reactor as the dewaxing catalyst. When the hydrotreating catalyst is in a separate reactor from the dewaxing catalyst, the feed rate is LHSV in the range of about 0.2 to about 5.0, preferably LHSV in the range of about 0.2 to about 2.0. The hydrogen supply (makeup and recycle) ranges from about 1500 to about 10,000 standard cubic feet per barrel of lubricant base stock, preferably from about 2000 to about 5,000 standard cubic feet per barrel of lubricant base stock.

The hydrotreating catalyst can be run at various temperatures depending on the desired product and feed type. In one embodiment, the hydrotreating catalyst can effectively hydrogenate aromatics in the feedstock to form an effluent. Effectively hydrogenating the aromatic compound means that the hydrotreating catalyst can reduce the aromatic compound content of the feedstock by at least 10%, preferably at least 20%, most preferably at least 30%. In a preferred embodiment, the hydrotreating catalyst is in the same reactor as the dewaxing catalyst, so the dewaxing catalyst and the hydrotreating catalyst are at the same temperature. In one embodiment, the temperature range typical for the process of the invention is about 450 ° F. to 750 ° F. In one embodiment, the temperature is about 600 ° F to 700 ° F. In further embodiments, the temperature is between about 600 ° F. and 675 ° F.

Taro  catalyst

Any dewaxing catalyst known in the art can be used as the dewaxing catalyst in the catalyst system of the present invention. Examples of dewaxing catalysts are described in US Pat. No. 7,141,529 and US Pat. No. 7,390,763, which is incorporated herein by reference in its entirety. Preferably, the dewaxing catalyst is a hydrowaxing catalyst comprising a hydrogenation component and an acidic component on a support such as a porous inorganic oxide. Suitable inorganic oxide supports include silica, alumina, titania, magnesia, zirconia, silica-alumina, silica-magnesia, silica-titania and the like, with alumina being preferred. The dewaxing catalyst also includes an acidic component which may itself be a support or may be a molecular sieve, such as a zeolite, clay or a combination thereof, dispersed in the support. Examples of acidic components include mesoporous crystalline molecular sieves having degradation activity such as silicalite or aluminosilicate zeolite ZSM-5. In one embodiment, the dewaxing catalyst comprises one or more Group VIII and / or VIB metals, alumina supports and mesoporous molecular sieves. For example, such a catalyst may be prepared by extruding a mixture of 30% by weight molecular sieve dispersion in 70% by weight alumina and impregnating Group VIII and / or Group VIB metals.

Generally, the dewaxing catalyst used in the present invention comprises 1) hydrogenated component and 2) acidic component. Preferred hydrogenation components are Group VIII metals such as platinum and / or palladium. Preferred acidic components are mesoporous molecular sieves.

Taro  Hydrogenation Components of the Catalyst

The dewaxing catalyst used in the present invention includes a hydrogenation component. Hydrogenation can be defined as a chemical reaction that results in the addition of hydrogen to an organic compound. Examples of the hydrogenation reaction include the addition of hydrogen to alkenes producing alkanes, the addition of hydrogen to aromatic compounds producing cycloalkanes and the addition of hydrogen to aldehydes producing alcohols. Group VIII metals are preferred hydrogenation components in the dewaxing catalyst used in the process of the invention.

As used herein, the term "metal" or "active metal" means one or more metals in some form, such as elemental state or sulfides, oxides and mixtures thereof. Thus, the Group VIII metal used in the process of the present invention may refer to one or more metals in some form, such as elemental state or sulfides, oxides and mixtures thereof. Regardless of whether the metal component is actually present, the concentration is calculated when it is present in the elemental state.

In one embodiment, the Group VIII metal used for dewaxing comprises platinum, palladium and mixtures thereof. Optionally, other catalytically active metals such as molybdenum, nickel, vanadium, cobalt, tungsten, rhodium, ruthenium, zinc, iridium, gold, silver, osmium and mixtures thereof may be included in the hydrogenation component of the dewaxing catalyst. The amount of metal ranges from about 0.01% to about 10%, preferably from about 0.1% to about 5%, more preferably from about 0.2% to about 1% by weight of the dewaxing catalyst. The amount of Group VIII metal used in the hydrogenation component of the dewaxing catalyst may vary, provided there is sufficient active metal to act as a catalyst in the hydrogenation of the hydrocarbon feedstock. In general, adding more than about 1% by weight of Group VIII metal does not significantly improve the catalytic activity and is therefore economically disadvantageous.

In one embodiment, the Group VIII metal is dispersed in the support. Preferably, the support is an inorganic oxide. The support may be catalytically active or inert, provided that the support provides sufficient surface area to disperse the Group VIII metal. In addition, promoter metal may be added to the catalyst. US Pat. No. 7,390,394 provides examples of inorganic oxides with catalytically active metals and promoters, which are incorporated herein by reference in their entirety. Many methods are known, including ion exchange, impregnation, coprecipitation, and the like, for depositing a compound comprising platinum and palladium metal or platinum and / or palladium on a support.

Taro  Acidic components of the catalyst

The dewaxing catalyst further includes an acidic component. The acidic component is selected from the group consisting of molecular sieves, amorphous inorganic oxides and clays. Preferably, the acid component is a mesoporous molecular sieve such as mesoporous zeolite, silicoaluminophosphate or borosilicate. More preferably, the acid component is a one-dimensional (1-D) mesoporous molecular sieve and “one-dimensional” is defined herein as a system of parallel one-dimensional channels that are comparable. Channel classification in zeolites as one-dimensional, two-dimensional, or three-dimensional is described by Zeolites, Science and Technology (editor: FR Rodrigues, LD Rollman and C. Naccache), NATO ASI Series, 1984 by RM Barrer. This reference is incorporated herein by reference (see page 75 in particular). Examples of 1-D zeolites include kancleanite hydrate, lomonite, mazarite; Mordenite and zeolite L are mentioned.

Preferably, the pores of the mesoporous molecular sieve are oval in shape, meaning that the pores represent two inequality axes, referred to herein as uniaxial and long axes. The term oval, as used herein, does not mean that a particular oval or elliptic shape is required, but rather a pore representing two inequality axes. The 1-D pores of the catalysts useful in the practice of the present invention may have a short axis of about 3.9 kV to about 4.8 kV and a long axis of about 5.4 kV to about 7.1 kV as determined by conventional X-ray crystallographic measurements.

An example of a medium-pore size molecular sieve for use in the method of the present invention is silicoaluminophosphate SAPO-11. SAPO-11 comprises a molecular structure of a corner covalent [SiO ₂ ] tetrahedron, [AlO ₂ ] tetrahedron and [PO ₂ ] tetrahedron [ie, (S _x Al _y P _z ) O ₂ tetrahedral units]. When combined with a Group VIII metal hydrogenation component, SAPO-11 converts the waxy component of the waxy feedstock to produce a lubricant with good yield, very low pour point, low viscosity and high viscosity index. SAPO-11 is described in detail in US Pat. No. 5,135,638, which is incorporated herein by reference in its entirety for all purposes.

Other mesoporous size silicoaluminophosphate molecular sieves useful in the methods of the present invention are SAPO-31 and SAPO-41, also disclosed in US Pat. No. 5,135,638.

Further examples of molecular sieves useful in the methods of the invention include zeolites ZSM-12, ZSM-21, ZSM-22, ZSM-23, ZSM-35, ZSM-38, ZSM-48, ZSM-57, SSZ-32, Perilite L and other molecular sieve materials based on aluminum phosphate, such as SM-3, SAPO-11, SAPO-31, SAPO-41, MAPO-11 and MAPO-31. The mesoporous size molecular sieve is preferably SAPO-11, SM-3, SSZ-32, ZSM 22 or ZSM 23. Mesoporous size molecular sieve catalysts are taught in US Pat. No. 5,282,958, US Pat. No. 7,468,126, US Pat. No. 6,204,426 and WO 99/45085, which are incorporated herein by reference.

In addition to the crystalline material, the dewaxing catalyst may comprise amorphous inorganic oxides such as silica, alumina, titania, zirconia, magnesia or combinations thereof. The inorganic oxides are porous, preferably mesoporous, and can contribute to the dewaxing activity of the catalyst by providing acidic sites. In some embodiments, the amorphous inorganic oxide may be nonreactive in that it does not impart any catalytic activity itself but only serves as a support for the hydrogenated and acidic components of the dewaxing catalyst. Consistent with the requirements of the lubricating oil hydrotreatment catalyst, the support should have an appropriate pore size and distribution to allow the relatively bulky components of the high boiling feed to enter the internal pore structure of the catalyst where the desired hydrotreating reaction takes place. To that extent, the catalyst typically has a minimum pore size of about 40 mm 3, ie, pores having a pore size of less than 40 mm 3 are about 5%, and most of the pores have a pore size in the range of 40 to 400 mm 3, preferably about Up to 30% has a pore size in the range of 200-400 mm 3. Preferred catalysts for the first stage have at least 60% of pores in the range from 40 to 200 mm 3. In one embodiment, the inorganic oxides may contribute to acidic sites for the dewaxing catalyst to increase the activity of the dewaxing catalyst. In another embodiment, the inorganic oxide can serve as a non-reactive support for hydrogenation components (ie, precious metals such as platinum) and acidic components (ie, acid zeolites). The inorganic oxide may be in the form of a cogel. In one embodiment, the dewaxing catalyst comprises alumina, noble metals and zeolites. In another embodiment, the dewaxing catalyst comprises 15 wt% to 85 wt% zeolite complexed with an alumina or silica inorganic oxide binder. In general, a binder such as alumina may be added during the dewaxing catalyst preparation. The binder may comprise 0 wt% to 95 wt%, preferably 15 wt% to 85 wt% of the dewaxing catalyst.

Techniques for introducing catalytically active metals into molecular sieves are known, and existing metal introduction techniques and treatment of molecular sieves to form active catalysts such as ion exchange, impregnation or blockage during sieve preparation are used in the present invention. Suitable for

Taro  Condition

In the process of the invention, at least a portion of the effluent from the reaction of the hydrotreating catalyst with the waxy feedstock is contacted with hydrogen over a second catalyst comprising a dewaxing catalyst. The dewaxing conditions depend on the balance of the feedstock used and the desired pour point, viscosity index and yield of the lubricating oil product. In general, the dewaxing catalysis takes place in the presence of hydrogen at a hydrogen pressure, preferably in the range from about 500 psia to 4000 psia, more preferably in the range from about 900 psia to about 3000 psia. The feed rate for the dewaxing catalyst is LHSV in the range of about 0.2 to about 5.0, preferably LHSV in the range of about 0.5 to about 2.5. The hydrogen supply makeup is standard cubic feet in the range of about 100 to about 15,000 per barrel of lubricant base stock, preferably standard cubic feet in the range of about 250 to about 1,500 per barrel of lubricant base stock. Hydrogen recirculation is standard cubic feet in the range of about 250 to about 10,000 per barrel of lubricant base stock, preferably standard cubic feet in the range of about 2500 to about 5,000 per barrel of lubricant base stock. The temperature may range from about 450 ° F. to about 750 ° F., preferably from about 550 ° F. to about 725 ° F., and most preferably from about 600 ° F. to about 675 ° F.

product

In one embodiment, the method of the present invention produces a lubricant. Lubricants have a pour point of less than about 0 ° C., preferably less than about −5 ° C., and most preferably less than about −10 ° C. as measured by ASTM D-97. In one embodiment, the lubricating oil product has a pour point in the range of -10 ° C to -45 ° C. The lubricating oil product may be further hydrotreated over one or more hydrotreating catalysts including the hydrofinishing catalyst to achieve the desired final lubricating oil product properties. For example, some or all of the lubricating oil product from the dewaxing catalytic reaction zone may be mildly hydrotreated or hydrofinished to remove the coloring material or hydrogenated aromatic species to meet the desired lubricant specifications. In general, the final lubricating oil product is a lubricating oil having an initial boiling point in the range of 600 to 1000 ° F. and a final boiling point in the range above 750 to 1300 ° F. Lubricant products generally have a viscosity in the range of 3 to 30 cSt and a viscosity index in the range of 95 to 170 at 100 ° C. as measured by ASTM D445.

The following examples are illustrative and are not intended to limit the scope of the invention as defined by the claims.

< Example >

Example  One.

A catalyst was prepared using an alumina base having a surface area of 150 m 2 / g, Hg indentation volume of 0.84 cc / g, and macropore volume of 0.075 cc / g, as calculated by nitrogen adsorption / desorption. The reaction mixture was formed by initial immersion of a solution of 0.16 grams of chloroplatinic acid and 0.2 grams of palladium dichloride in 18 mL of 1% HCl in deionized water to impregnate 20 grams (based on volatiles) without alumina base. The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then calcined at 300 ° C. for additional hours to form the final hydrotreating catalyst. The final hydrotreating catalyst had Pt and Pd contents of 0.3% and 0.6% by weight, respectively.

Example  2.

80% pseudoboehmite alumina (Versal 250 alumina, UOP), 10% boehmite alumina (Catapal B, Sasol) and 10% milled calcined alumina fine (325 Tyler) B catalyst was prepared from a mixture of less than one mesh). The alumina powder was dry mixed for 10 minutes in a Baker-Perkin mixer and then sprayed onto a 62% volatile target with 4% nitric acid containing solution to form a wet dough. The wet dough was mixed for a total of 30 minutes, then transferred to a Loomis RAM extruder and passed through a 1/16 "die insert to form an extrudate. The extrudate was dried at 130 ° C. for 30 minutes with high airflow and 680 ° C. in air. The calcined alumina base was formed by calcination for 1 hour at sig .. The resulting calcined alumina base was a surface area of 260 m 2 / g, a Hg indentation volume of 0.62 cc / g and a macro of 0.001 cc / g as calculated by nitrogen adsorption / desorption. The calcined alumina base was then impregnated with Pt and Pd using the same procedure as described in Example 1. The final catalyst had Pt and Pd contents of 0.3% and 0.6% by weight, respectively.

Example  3.

The C catalyst was prepared using an alumina base having a surface area of 192 m 2 / g, Hg indentation volume of 0.75 cc / g, and macropore volume of 0.01 cc / g, as calculated by nitrogen adsorption / desorption. The reaction mixture was formed by initial immersion with a pH 9.7 adjusted aqueous solution of 3.1% Pt as tetraamine dinitrate salt and impregnated with 99 grams (based on volatile free) alumina base. The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then calcined at 370 ° C. for additional hours to form the final hydrotreating catalyst. The final catalyst had a Pt content of 1% by weight.

Example  4.

D catalyst was prepared from a mixture of 75% pseudoboehmite alumina (Versal 250 alumina, UOP), 5% boehmite alumina (Catapal B, Sasol) and 20% milled calcined alumina fine (less than 325 Tyler mesh). The alumina powder was dry mixed for 10 minutes in a small Littleford mixer and then sprayed onto a 60% volatile target with 1.7% nitric acid containing solution to form a wet dough. The wet dough was mixed for a total of 10 minutes, then neutralized again with a solution of 15% NH ₄ OH to 61% final volatile target and mixed for an additional 10 minutes. The resulting wet mixture was transferred to a Bonnot extruder equipped with a 2 "auger and extruded through a 1/16" die insert to form an extrudate. The extrudate was dried at 130 ° C. for 30 minutes in a high air stream and calcined at 815 ° C. for 1 hour in air to form an alumina base. The alumina base had a surface area of 185 m 2 / g, an Hg indentation volume of 0.84 cc / g and a macropore volume of 0.05 cc / g as calculated by nitrogen adsorption / desorption. 10 grams (volatiles ratio) by initial immersion with a solution of 0.03 grams of platinum (as tetraamine dinitrate salt) and 0.06 grams of palladium (as tetraamine dinitrate salt) in 8.5 ml deionized water adjusted to pH 9.0 The reaction mixture was formed by impregnation of the base). The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then calcined at 300 ° C. for additional hours to form the final hydrotreating catalyst. The final hydrotreating catalyst had Pt and Pd contents of 0.3% and 0.6% by weight, respectively.

Example  5.

E catalysts were prepared using the same calcined alumina base described in Example 4. Initial immersion with a solution of 0.03 grams of platinum (as tetraamine dinitrate salt) and 0.06 grams of palladium (as tetraamine dinitrate salt) in 8.5 ml deionized water adjusted to pH 1.0 by addition of dilute nitric acid The reaction mixture was formed by impregnating grams (based on no volatiles) of the calcined alumina base. The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then calcined at 300 ° C. for additional hours to form the final hydrotreating catalyst. The final hydrotreating catalyst had Pt and Pd contents of 0.3% and 0.6% by weight, respectively.

Example  6.

The F catalyst was prepared from a silica alumina base using the recipe already described in Example 2 of US Pat. No. 5,393,408, which is incorporated herein by reference. The silica alumina base had a surface area of 415 m 2 / g, an Hg indentation volume of 0.74 cc / g and a macropore volume of 0.03 cc / g as measured by nitrogen adsorption / desorption. 50 grams (volatiles ratio) by initial immersion with a solution of 0.15 grams of platinum (as tetraamine dinitrate salt) and 0.3 grams of palladium (as tetraamine dinitrate salt) in 45 mL of deionized water adjusted to pH 9.0. The reaction mixture was formed by impregnating silica alumina base). The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then calcined at 400 ° C. for an additional time to form the final hydrotreating catalyst. The final hydrotreating catalyst had Pt and Pd contents of 0.3% and 0.6% by weight, respectively.

Example 7

A G catalyst was prepared from the same silica alumina base described in Example 6 and impregnated with platinum and palladium using the same procedure described in Example 6 except that the platinum and palladium contents were 0.2% and 0.16% by weight, respectively. It was.

Example  8.

82% silica-alumina (Siral 30, Sasol), 14% boehmite alumina (Catapal B, Sasol) and 4% milled calcined silica-alumina fine (350 mesh) with alumina to silica ratio of 70:30 H catalyst was prepared from a mixture of " The alumina and silica-alumina powders were dry mixed in a small Baker-Perkin mixer for 20 minutes and then sprayed onto a 62% volatile target with 4% nitric acid containing solution to form a wet dough. The wet dough was mixed for a full 30 minutes, then transferred to a Lumis RAM extruder and passed through a 1/16 "die insert to form an extrudate. The extrudate was dried at 130 ° C. for 30 minutes with high airflow and at 680 ° C. in air for 1 hour. Calcination to form a silica-alumina base The resulting silica-alumina base yields a surface area of 400 m 2 / g, an Hg indentation volume of 0.74 cc / g and a macropore volume of 0.03 cc / g, as calculated by nitrogen adsorption / desorption. 10 grams (volatilized) initially with a solution of 0.03 grams of platinum (as tetraamine dinitrate salt) and 0.06 grams of palladium (as tetraamine dinitrate salt) in 8.5 ml of deionized water adjusted to pH 9.0 The reaction mixture was formed by impregnating a silica-alumina base (based on no water) The reaction mixture was immersed for 24 hours and then dried at 150 ° C. for 1 hour and then further Calcined at 300 ℃ for liver to form the final hydrotreating catalyst. The final hydrotreating catalyst had a platinum and palladium content of 0.3 weight% and 0.6 weight% respectively.

Example  9.

To prepare a catalyst J from the same silica-alumina base material as described in Example 6, was added to MgNO ₃ .2H ₂ O (magnesium nitrate in water, dehydrated) 16.4 grams of the impregnating solution silica-, except that inhibit alumina base pH It was impregnated with platinum and palladium using the same procedure described in Example 6. The final catalyst had a platinum and palladium content of 0.3% and 0.6% by weight and magnesium content of 3% by weight, respectively.

Example  10.

To prepare a catalyst K from the same silica-alumina base material as described in Example 6, was added to MgNO ₃ .2H ₂ O (magnesium nitrate in water, dehydrated) 24.6 grams of the impregnating solution silica-, except that inhibit alumina base pH It was impregnated with Pt and Pd using the same procedure described in Example 6. The final catalyst had a platinum and palladium content of 0.3% and 0.6% by weight and magnesium content of 4.5% by weight, respectively.

Example  11.

Example 6 except that the L catalyst was prepared from the same silica-alumina base described in Example 6, and 5.6 grams of Na ₂ NO ₃ (sodium nitrate) was added to the impregnation solution to inhibit the silica-alumina base acidity. It was impregnated with Pt and Pd using the same procedure described. The final catalyst had a platinum and palladium content of 0.3% and 0.6% by weight and magnesium content of 3% by weight, respectively.

Example  12.

Example 6 except that the M catalyst was prepared from the same silica-alumina base described in Example 6, and 11.3 grams of Na ₂ NO ₃ (sodium nitrate) was added to the impregnation solution to inhibit silica-alumina base acidity. It was impregnated with platinum and palladium using the same procedure described. The final catalyst had a platinum and palladium content of 0.3% and 0.6% by weight and magnesium content of 6% by weight, respectively.

Of A-M hydrotreating catalyst Hydrogenolysis  activation

The AM hydrotreating catalyst was treated for use in the layered catalyst system of the present invention. Hydrotreated catalysts having a cracking activity of less than 10% at 700 ° F., as measured by decalin conversion, can be used in the methods and catalyst systems of the present invention. The cracking activity of the hydrotreating catalyst was evaluated using a model feed mixture consisting of 42% cis and 58% trans decahydronaphthalene aka decalin (C-10). The exact ratio of cis and trans decalin in the feed mixture is not expected to be important unless each component differs by more than +/- 5% from this composition.

Decalin  Conversion Rate

For all catalyst screening tests, the WHSV, gas velocity and unit pressure were kept constant. Analysis of the feed and product hydrocarbon distributions was performed using an online GC analysis. For all catalyst tests, the catalyst was reduced and dried in flowing H ₂ and then pretreated with amine solution before being introduced into the decalin model compound feed.

The protocol for the catalyst test is as follows:

1) 0.5 grams of ground 24 to 48 mesh catalyst was charged into a reactor, typically in the center of a ¼ "stainless steel pipe, and the remaining dead space was filled with 48 to 80 mesh inert alunderm.

2) The H ₂ flow was adjusted to 160 ml / min at ambient pressure.

3) The reactor temperature was raised to 750 ° F. and maintained for 1 hour.

4) The reactor was cooled to 500 ° F.

5) The reactor was pressurized to 2000 psig and adjusted to ensure H ₂ flow once again at 160 ml / min (based on ambient pressure).

6) The catalyst was titrated with a solution of 500 ppm t-butylamine (Aldrich 98%) in n-heptane (Aldrich 99%) for 18 hours at a rate of 0.025 mL / min (WHSV of 2.05).

7) The titration feed was stopped and the decalin feed (Aldrich 99%) spiked with 5 ppm t-butylamine (Aldrich 98%) was pumped into the reactor at a rate of 0.01 ml / min (WHSV of 1.08).

8) After 4 h stabilization, the product stream was sampled using online GC to assess the decalin conversion at 500 ° F. Since the conversion of decalin to degradation products occurs at or rarely at this temperature, data points were used to establish the GC baseline for unreacted decalin.

9) Thereafter, the reactor temperature was increased to 700 ° F. and stabilized for 1 hour before the final decalin conversion analysis was repeated. Typically 2-4 data points were taken and averaged over the 500 ° F and 700 ° F temperature points.

Summary of test conditions for decalin conversion:

Catalyst amount: 0.5 g

H ₂ flow rate: 160 ml / min

Titration feed liquid flow rate: 0.025 ml / min (2.05 WHSV)

Decal feed liquid flow rate: 0.01 ml / min (1.08 WHSV)

System overall pressure: 2000 psig

It should be noted that as long as the hydrogen gas flow rate and the liquid flow rate are proportional, fewer or more catalysts can be tested.

Data Analysis

The catalytic residual cracking activity is based on the conversion of cis + trans decalin to the cracking product at 700 ° F compared to 500 ° F (no conversion to light product is expected). The ring-opening conversions of decalin to other C ₁₀ isomers were grouped together on a weight percent basis as non-degradable products. Therefore, iso decalin groups are defined as products that have a molecular weight greater than nC9 and include trans decalin. There was no difference with respect to the relative distribution of the different hard degradation products.

Using FID analysis, assuming a response factor of 1 the area% of the desired peaks and groups was calculated for all hydrocarbons.

% Decomposition conversion = (1-[(total C ₁₀ remaining at 700 ° F) / (total C ₁₀ remaining at 500 ° F)]) x 100

Hydrotreatment Catalyst Test Results

The A-M hydrotreating catalysts described in Examples 1-12 were all evaluated for degradation activity using the decalin conversion test described above. The results are summarized below:

A, B, C, D, J, K, L and M hydrotreating catalysts having a decalin conversion of less than 10% were used in the catalyst system of the present invention and the process of the present invention. A, B, C, D, J, K, L and M hydrotreating catalysts having a decalin conversion of less than 10% yield lubricating oil product at a target pour point within 2% over the dewaxing temperature range when used in the layered catalyst system of the present invention. Was maintained. A, B, C, D, J, K, L and M hydrotreating catalysts having a decalin conversion of less than 10% maintained the lubricating oil product yield at the target pour point over the dewaxing temperature range when using the process of the present invention. Conventional hydrotreating catalysts of F, G, and H with decalin conversions greater than 10% cannot be used in the catalyst system of the present invention and the process of the present invention. The catalysts of F, G and H lost lubricating oil yields above 2% at the target pour point over the dewaxing temperature range.

Lubricant Preparation at the Target Pour Point

Example  13.

Waxy hydrocrackates having an API of 32.5, a 10% wax content and a viscosity of 5.4 cSt at 100 ° C. were dewaxed throughout the hydrotreating reaction zone, the dewaxing reaction zone and the hydrofinishing reaction zone. The hydrotreating catalyst in the hydrotreating reaction zone is 0.64 wt.% Pt on the non-acidic potassium neutralized L-zeolite support having an expected decalin conversion of less than 10%. The dewaxing catalyst in the dewaxing reaction zone is 0.325% by weight Pt on the bound zeolite catalyst comprising 65% SSZ-32 on alumina. Hydrofinishing catalysts in the hydrofinishing reaction zone are 0.2% Pt, 0.16% Pd bound to cyral 40 and alumina. The process conditions used were an LHSV of 1.0, a gas to oil ratio of 4000 scf / bbl and a total pressure of 2300 psig, with a target pour point of -15 ° C. The reaction temperature is 450 ° F. for the hydrotreating reaction zone, 600-650 ° F. for the dewaxing reaction zone (adjusted to achieve a target pour point of −15 ° C.) and 450 ° F. for the hydrofinishing reaction zone. Lubricant yield is 91%.

Example  14.

Waxy hydrocrackates having an API of 32.5, a 10% wax content and a viscosity of 5.4 cSt at 100 ° C. were dewaxed throughout the first reaction zone, second reaction zone and third reaction zone. The hydrotreating catalyst in the first reaction zone is 0.64% by weight Pt on the non-acidic potassium neutralized L-zeolite support having an expected decalin conversion of less than 10%. The dewaxing catalyst in the second reaction zone is 0.325% by weight Pt on the bound zeolite catalyst comprising 65% SSZ-32 on alumina. Hydrofinishing catalyst in the third reaction zone is 0.2% Pt, 0.16% Pd bound to cyral 40 and alumina. The process conditions used were an LHSV of 1.0, a gas to oil ratio of 4000 scf / bbl and a total pressure of 2300 psig, with a target pour point of -15 ° C. The reaction temperature is 650 ° F. for the hydrotreating reaction zone, 600-650 ° F. for the dewaxing reaction zone (adjusted to achieve a target pour point of −15 ° C.) and 450 ° F. for the hydrofinishing reaction zone. Lubricant yield is 90.5%.

Example  15 ( Comparative Example ).

Example 15 was run under the same conditions as in Example 13 without the hydrotreating reaction zone. Lubricant yield is 89%.

The results and reaction conditions for Examples 13-15 are summarized in Table 2 below.

Examples 13-14 above show maintenance of lubricating oil yield at a target pour point within about 2% at dewaxing temperatures (450 ° F. and 650 ° F.) when using the method of the present invention. Example 15 shows the yield of lubricating oil without the hydrotreatment layer.

Example  16.

Waxy hydrocrackates having an API of 30.6, a 12% wax content and a viscosity of 6.15 cSt at 100 ° C. were dewaxed throughout the first reaction zone, second reaction zone and third reaction zone. The hydrotreating catalyst in the first reaction zone is a G catalyst with a decalin conversion of 65%. The dewaxing catalyst in the second reaction zone is 0.325% by weight Pt on the bound zeolite catalyst comprising 65% SSZ-32 on alumina. The hydrofinishing catalyst in the third reaction zone is also a G catalyst. Process conditions are LHSV of 1.6 based on dewaxing reaction zone, gas to oil ratio of 4000 scf / bbl and 2300 psig total pressure; The LHSV for the first zone is 10 hours ⁻¹ . The product target pour point is −15 ° C. required for the dewaxing zone maintained at 645 ° F. to 655 ° F. The reaction temperature for the hydrotreating reaction zone varies from 250 ° F to 700 ° F; The hydrofinishing reaction zone was maintained at 450 ° C. The temperature of the reaction zone varied from 650 ° F. to 700 ° F. to assess the effect of temperature on lubricating oil yield. The yield of lubricating oil is 94 ± 1% over a temperature range of 170 ° F. to 600 ° F. in the first reaction zone. The yield dropped 2% to 92% when the first reaction zone was maintained at 650 ° F. The yield drop was approximately 4% at 665 ° C., even higher at temperatures of 680 ° F. and 700 ° F. When bypassing the first reaction zone, the lubricant yield is 93.5%. The results are summarized in Table 3 below.

Example  17.

Waxy hydrocrackates having an API of 38.9, a 33% wax content and a viscosity of 4.1 cSt at 100 ° C. were dewaxed throughout the first reaction zone, second reaction zone and third reaction zone. The hydrotreating catalyst in the first reaction zone is a catalyst with 0.5 wt% Pt and 0.5 wt% Li impregnated in the alumina support having an expected decalin conversion of less than 10%. The dewaxing catalyst in the second reaction zone was 1.24 wt% Ca ion exchanged in the HSSZ-32 zeolite powder and then impregnated with 0.5 wt% Pt. The hydrofinishing catalyst in the third reaction zone is also a G catalyst. Process conditions are 0.85 h ⁻¹ LHSV based on dewaxing reaction zone, gas to oil ratio of 4000 scf / bbl and 2300 psig total pressure; The LHSV for the first zone is also 0.85. The product target pour point is −15 ° C. required for the dewaxing zone maintained at 595 ° F. to 608 ° F. The reaction temperature for the hydrotreating reaction zone varies from 450 ° F to 650 ° F; The hydrofinishing reaction zone was maintained at 450 ° C. The yield of lubricating oil is 74% ± 0.5. When bypassing the first reaction zone, the lubricating oil yield from the second reaction zone and the third reaction zone is 75%. The results are summarized in Table 4 below.

Example  18.

Waxy hydrocrackates having an API of 38.9, a 33% wax content and a viscosity of 4.1 cSt at 100 ° C. were dewaxed throughout the first reaction zone, second reaction zone and third reaction zone. The hydrotreating catalyst in the first reaction zone is a G catalyst with a decalin conversion of 65%. The dewaxing catalyst in the second reaction zone was 1.24 wt% Ca ion exchanged on the zeolite support of SSZ-32 zeolite and then impregnated with 0.5 wt% Pt. The hydrofinishing catalyst in the third reaction zone is also a G catalyst. Process conditions are an LHSV of 0.85, a gas-to-oil ratio of 4000 scf / bbl and a total pressure of 2300 psig. The product target pour point is approximately −40 ° C. required for the dewaxing zone maintained at 610 ° F. to 630 ° F. The reaction temperature for the hydrotreating reaction zone is 650 ° F .; The hydrofinishing reaction zone was maintained at 450 ° F. The yield of lubricating oil is shown in Table 5 below. Compared to systems running under similar conditions but lacking the hydrotreatment layer, the lubricating oil yield is greater than approximately 18% for systems without the hydrotreatment layer.

Examples 16 and 18 show a loss of lubricating oil yield (> 2%) at the target pour point at dewaxing temperature (650 ° F. or higher) when using a catalyst exhibiting high decalin conversion in the hydrotreatment bed prior to the dewaxing bed. Example 17 (Table 4) shows the maintenance of the yield of lubricating oil when the catalyst in the hydrotreatment layer has a low decalin conversion.

Example  19.

Waxy hydrocrackates having an API of 34.8, a 35% wax content and a viscosity of 7.9 cSt at 100 ° C. were dewaxed throughout the first reaction zone, second reaction zone and third reaction zone. The hydrotreating catalyst in the first reaction zone is a D catalyst with a decalin conversion of 2.7%. The dewaxing catalyst in the second reaction zone is a bonded noble metal zeolite catalyst having 65% zeolite SSZ-32 bonded to alumina and containing 0.325% by weight Pt and promoted with magnesium. The hydrofinishing catalyst in the third reaction zone is a G catalyst. Process conditions are LHSV of 2.0 based on combined hydrotreatment and dewaxing reaction zone, gas to oil ratio of 4000 scf / bbl, and 2300 psig total pressure; For the first zone the LHSV is 6.7 and for the second zone 2.4. The product target pour point is −16 ° C. required for the dewaxing zone maintained at 680 ° F. The reaction temperature for the hydrotreating reaction zone was kept the same as the dewaxing zone and the hydrofinishing reaction zone was maintained at 450 ° F. The yield of lubricating oil is 87.6%. The data is also presented at a similar product pour point in the absence of the first reaction zone, which requires a temperature of 665 ° F. and yields a measured 85% yield.

From this example, it can be seen that the lubricating oil yield is maintained and even increased at a temperature of 680 ° C. by the method of the present invention.

There are a variety of variations on the present invention possible in the teachings described herein and in the examples supporting it. It is, therefore, to be understood that within the scope of the claims, the invention may be practiced otherwise than as specifically described or illustrated herein.

Claims (22)

A method of producing lubricating oil by dewaxing a waxy hydrocarbon feedstock by catalytic reaction,
a) contacting the waxy hydrocarbon feedstock in the first reaction zone with a hydrotreating catalyst under hydrotreating conditions in which the aromatics content of the feedstock is reduced to form a first effluent; And
b) in a second reaction zone, contacting at least a portion of the first effluent with a dewaxing catalyst under dewaxing conditions to produce lubricating oil, thereby producing a lubricating oil having a pour point lower than the pour point of the first effluent; ,
The hydrotreating catalyst is
Iii) a Group VIII metal supported on an inorganic oxide support;
Ii) exhibit a decalin conversion of less than 10% at 700 ° F .;
Iii) less than 0.25 meq of acid sites per gram of said catalyst. The method of claim 1,
The aromatics content of the feedstock is reduced by at least 20%. The method of claim 1,
The aromatics content of the feedstock is reduced by at least 30%. The method of claim 1,
Wherein the temperature range of the dewaxing process is between 450 ° F and 750 ° F. 5. The method of claim 4,
Wherein the temperature range of the dewaxing process is between 600 ° F. and 675 ° F .; The method of claim 1,
The dewaxing conditions and the hydrotreating conditions are the same. The method of claim 1,
The target pour point is in the range of -10 ° C to -45 ° C. The method of claim 1,
The hydrotreating catalyst and the dewaxing catalyst are in the same reactor. The method of claim 1,
Wherein said hydrotreating catalyst and said dewaxing catalyst are present in a ratio of about 1:20 to about 1: 2. The method of claim 9,
Wherein said hydrotreating catalyst and said dewaxing catalyst are present in a ratio of about 1:20 to about 1:10. The method of claim 1,
Wherein said feedstock comprises less than about 10 ppm nitrogen. The method of claim 1,
Wherein said feedstock comprises less than about 2 ppm nitrogen. The method of claim 1,
Wherein said inorganic oxide comprises an amorphous material. 14. The method of claim 13,
The inorganic oxide is selected from the group consisting of silica, alumina, titania, magnesia, zirconia and combinations thereof. The method of claim 1,
Wherein said inorganic oxide comprises a crystalline material. The method of claim 15,
The inorganic oxide is selected from the group consisting of silico-aluminophosphate, zeolite, metalloaluminophosphate, and combinations thereof. The method of claim 1,
The Group VIII metal is platinum, palladium or a combination thereof. The method of claim 1, further comprising contacting at least a portion of the lubricant with a hydrofinishing catalyst in a third reaction zone. As a layered catalyst system,
a) a hydrotreating catalyst comprising a Group VIII metal supported on an inorganic oxide support and exhibiting a decalin conversion of less than 10% at 700 ° F .; And
b) a dewaxing catalyst comprising an acidic component selected from the group consisting of zeolites, zeolite analogues, non-zeolitic molecular sieves, acidic clays and combinations thereof, and Group VIII metals;
Wherein said hydrotreating catalyst and said dewaxing catalyst are present in a ratio of about 1:20 to about 1: 2. The method of claim 19,
The Group VIII metal of the hydrotreating catalyst is platinum, palladium or a combination thereof. The method of claim 19,
The Group VIII metal of the dewaxing catalyst is platinum, palladium or a combination thereof. The method of claim 19,
Said inorganic oxide is selected from the group consisting of silica, alumina, titania, magnesia, zirconia, silicoaluminophosphate, zeolite, metalloaluminophosphate and combinations thereof.