CN116829683A

CN116829683A - Method for producing high quality base oils using two stage hydrofinishing

Info

Publication number: CN116829683A
Application number: CN202280014086.6A
Authority: CN
Inventors: 张义华; S·巴塔查里亚; 雷光韬
Original assignee: Chevron USA Inc
Current assignee: Chevron USA Inc
Priority date: 2021-01-19
Filing date: 2022-01-18
Publication date: 2023-09-29

Abstract

Processes for economically and/or efficiently producing base oils having one or more improved properties, such as lower aromatics, are described. In some embodiments, the process involves two (or more) stage hydrofinishing, which advantageously provides a base oil with lower aromatics than a comparable one-stage process.

Description

Method for producing high quality base oils using two stage hydrofinishing

Cross Reference to Related Applications

The present application claims priority from U.S. provisional application Ser. No. 63/138,810, filed on 1 month 19 of 2021, and U.S. patent application Ser. No. 17/153,865, filed on 1 month 20 of 2021, the disclosures of which are incorporated herein in their entireties.

Technical Field

The present disclosure relates to methods for producing high quality base oils using, for example, novel multi-stage hydrofinishing processes.

Background of the applicationdescription of the application

Modern refinery processes for producing lubricating oils from crude oil typically use a number of hydrogen processes. These processes are employed to produce lubricating oils having suitable lubricating properties over a wide range of operating conditions. Hydrotreating/hydrocracking is generally a upgrading process for increasing viscosity index by removing low viscosity index molecules, including sulfur and nitrogen containing molecules. Hydrodewaxing is generally a process used to improve low temperature properties by isomerizing long chain waxy molecules that, if not otherwise removed, may negatively impact the pour and cloud points of the fractions. Hydrofinishing generally describes a process for further upgrading the quality of lubricating base oils (including color and oxidative stability) often by saturating the aromatic molecules. However, in many cases, the base oil may still have undesirable levels of aromatics, residual organic sulfur, and/or nitrogen. It would therefore be desirable if additional or alternative processes could be found for economically and efficiently producing base oils with one or more improved properties.

Advantageously, the present process economically and/or efficiently produces base oils having one or more improved properties (e.g., lower aromatics). In one embodiment, the process comprises a method for producing a low aromatic base oil, the method comprising: the SSZ-91 isomerized stream is first contacted with a noble metal hydrofinishing catalyst under hydrofinishing conditions 1 to provide a hydrofinishing stream 1. The 1 st hydrofinishing stream is then contacted with a second noble metal hydrofinishing catalyst under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream. Typically, the 2 nd hydrofinishing conditions include a lower temperature than the 1 st hydrofinishing conditions.

In another embodiment, the present application relates to a process for producing a low aromatic base oil, the process comprising: the hydrocarbon feedstock is first contacted under hydroisomerization dewaxing conditions with hydrogen and a catalyst comprising crystalline molecular sieve SSZ-91 and platinum to provide an isomerized stream. The isomerised stream is then contacted under hydrofinishing conditions 1 with a catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum or a combination thereof. The catalyst may comprise a noble metal content of about 0.1 to about 0.6 wt.%. The 1 st hydrofinishing stream is then contacted under 2 nd hydrofinishing conditions with a catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum or a combination thereof. The catalyst may comprise a noble metal content of about 0.1 to about 0.6 wt.%. Generally, the 2 nd hydrofinishing conditions include a lower temperature than the 1 st hydrofinishing conditions. Advantageously, the base oils produced by the process often contain at least about 40% by weight less aromatic hydrocarbons than comparable processes employing a single hydrofinishing step.

Other features of the disclosed design and advantages provided thereby will be explained in more detail below with reference to specific exemplary embodiments shown in the drawings.

Drawings

Figure 1 shows a simplified process flow scheme with one stage hydrofinishing.

Figure 2 shows a simplified process flow scheme with two-stage hydrofinishing.

Detailed Description

Although illustrative embodiments of one or more aspects are provided herein, the disclosed processes can be implemented using a number of techniques. The disclosure is not to be limited to the illustrative or specific embodiments, figures, and techniques shown herein, including any exemplary designs and embodiments shown and described herein, and may be modified within the scope of the appended claims along with their full scope of equivalents.

The following description of the embodiments provides non-limiting representative examples of reference numerals to specifically describe features and teachings of various aspects of the invention. The described embodiments should be considered to be capable of implementation alone or in combination with other embodiments from the description of the embodiments. Those of ordinary skill in the art who review the description of the embodiments will be able to learn and understand the various described aspects of the invention. The description of the embodiments should be taken as an illustration of the invention as long as other implementations not specifically contemplated but within the knowledge of one skilled in the art having read the description of the embodiments are to be understood as consistent with the application of the invention.

Definition of the definition

The following terms used herein have the meanings as defined herein below unless otherwise indicated.

The term "hydrotreating" refers to a process or step performed in the presence of hydrogen for hydrodesulfurization, hydrodenitrogenation, hydrodemetallization and/or hydrodearene of components (e.g., impurities) of a hydrocarbon feedstock and/or for hydrogenation of unsaturated compounds in the feedstock. Depending on the type of hydrotreatment and the reaction conditions, the products of the hydrotreatment process can have, for example, improved aromatics content, viscosity index, saturates content, low temperature properties, volatility, and depolarization.

As used herein, the term "molecular sieve" refers to a crystalline material containing uniformly sized pores, cavities or interstitial spaces in which molecules small enough to pass through the pores, cavities or interstitial spaces are adsorbed, while larger molecules are not adsorbed. Examples of molecular sieves include zeolite and non-zeolite molecular sieves, such as zeolite analogs including, but not limited to, SAPO (silicoaluminophosphate), meAPO (metalloaluminophosphate), alPO ₄ And ELAPO (nonmetallic substituted aluminophosphate family).

As used herein, the term "pour point" refers to the temperature at which oil will begin to flow under controlled conditions. Pour point may be determined by, for example, ASTM D5950.

By "target pour point" is meant the pour point desired or required for the lube base oil product. The target pour point is typically less than about-10 ℃, and typically in the range of about-10 ℃ to-50 ℃, and in some embodiments, about-5 ℃ to 20 ℃.

As used herein, "cloud point" refers to the temperature at which a lubricating oil sample begins to develop haze when the oil cools under certain conditions. The cloud point of the lubricant base oil is complementary to its pour point. Cloud point can be determined by, for example, ASTM D5773.

"pour point/cloud point spread" or "pour-haze spread" of a base oil refers to the spread or difference between the cloud point and the pour point, and is defined as the cloud point minus the pour point, as measured in degrees celsius. In general, it is desirable to minimize the difference between pour point and cloud point.

The periodic Table of the elements referred to in this disclosure is the CAS version published by Chemical Abstract Service in Handbook of Chemistry and Physics, 72 th edition (1991-1992).

"group VIII metal" refers to an elemental metal selected from group VIII of the periodic table of elements and/or metal compounds comprising such metals.

Unless otherwise indicated, the "feed rate" of hydrocarbon or other feedstock to the catalytic reaction zone is expressed herein as the feed volume per volume of catalyst per hour, which may be referred to as the Liquid Hourly Space Velocity (LHSV), and is expressed in reciprocal of hours (h ^-1 )。

The term "hydroisomerization" refers to a process in which normal paraffins (normal paraffins) are isomerized to their more branched counterparts in the presence of hydrogen over a hydroisomerization (dewaxing) catalyst.

Unless otherwise indicated, the recitation of the types of elements, materials, or other components from which a single component or a mixture of components may be selected is intended to include all possible subcombinations of the listed components and mixtures thereof. In addition, "including" and variations thereof are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that may also be useful in the materials, compositions, and methods of this invention.

In some embodiments, the properties of the materials described herein can be determined as follows:

(a)SiO ₂ /Al ₂ O ₃ ratio (SAR): determined by ICP elemental analysis. Infinite (+) SAR indicates that there is no aluminum in the zeolite, i.e., the silica to alumina molar ratio is infinite. In this case, the molecular sieve is substantially entirely constituted by silicaAnd (3) forming the finished product.

(b) Surface area: through N ₂ Adsorption at its boiling point temperature. BET surface areas were calculated by the 5-point method at P/p0=0.050, 0.088, 0.125, 0.163, and 0.200. The sample is first pre-treated in the presence of flowing dry N2 at 400 ℃ for 6 hours to eliminate any adsorbed volatiles such as water or organics.

(c) Micropore volume: through N ₂ Adsorption at its boiling point temperature. Micropore volume at P/P by t-curve method ₀ Calculated at=0.050, 0.088, 0.125, 0.163, and 0.200. First, the sample is dried in flow N ₂ Pretreatment is carried out in the presence of 400 ℃ for 6 hours in order to eliminate any adsorbed volatiles such as water or organics.

(d) Mesoporous pore size: through N ₂ Adsorption at its boiling point temperature. Mesoporous pore size is according to N by the BJH method described in the following documents ₂ Isotherm calculation: "The determination of pore volume and area distributions in porous substations.I.computations from nitrogen isotherms" J.am.chem.Soc.1951, 73,373-380, of E.P.Barrett, L.G.Joyner and P.P.Halenda. First, the sample is dried in flow N ₂ Pretreatment is carried out in the presence of 400 ℃ for 6 hours in order to eliminate any adsorbed volatiles such as water or organics.

(e) Total pore volume: by at P/P ₀ N at =0.990 ₂ Adsorption at its boiling point temperature. First, the sample is dried in flow N ₂ Pretreatment is carried out in the presence of 400 ℃ for 6 hours in order to eliminate any adsorbed volatiles such as water or organics.

(f) The weight percent aromatics are determined by UV absorption at wavelengths of 220nm to 400nm as in ASTM D2008.

All publications, patents and patent applications cited in this application are incorporated herein by reference in their entirety to the extent permitted so long as such disclosure is not inconsistent with this application.

General Process of the application Using the 1 st hydrofinishing stream and the 2 nd hydrofinishing stream

The process of the present application generally comprises a hydrofinishing process comprising two or more or three or more stages or steps conducted under varying conditions such as temperature to produce a low aromatic base oil. Typically, the process includes contacting the isomerized stream with a noble metal hydrofinishing catalyst under 1 st hydrofinishing conditions to provide a 1 st hydrofinished stream.

The 1 st hydrofinishing stream is then contacted with a second noble metal hydrofinishing catalyst under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream, the 1 st hydrofinishing conditions and 2 nd hydrofinishing conditions (and 3 rd hydrofinishing conditions, 4 th hydrofinishing conditions or more hydrofinishing conditions, if employed) may be selected from those described below for hydrofinishing and may vary depending on the feedstock and desired base oil product and properties.

Although other 1 st and 2 nd hydrofinishing conditions (such as pressure, feed rate, catalyst, etc.) may be the same or different, typically in some embodiments of the application, the 2 nd hydrofinishing conditions include a lower temperature than the 1 st hydrofinishing conditions. This often results in surprisingly and unexpectedly low amounts of aromatic hydrocarbons in the base oils produced as shown in the examples below.

The temperature differential employed between the 1 st hydrofinishing and the 2 nd hydrofinishing may be selected based on the desired throughput, desired products and properties, equipment employed and other process parameters. In some embodiments, the 2 nd hydrofinishing conditions include a temperature lower than the 1 st hydrofinishing conditions, wherein the temperature of the 2 nd hydrofinishing conditions may be at least about 80°f, or at least about 90°f, or at least about 100°f, or at least about 120°f, or at least about 140°f, or at least about 160°f, or at least about 180°f, or at least about 200°f, or at least about 220°f, or at least about 250°f up to a temperature differential of not more than about 450°f, or not more than about 350°f, or not more than about 325°f, or not more than about 300°f, as compared to the 1 st hydrofinishing conditions.

The particular temperatures employed in the 1 st hydrofinishing conditions and the particular lower temperatures employed in the 2 nd hydrofinishing conditions may vary depending on the desired throughput, desired products and properties, equipment employed and other process parameters. Generally, the 1 st hydrofinishing conditions may include the following temperatures: about 475°f, or about 500°f, or about 510°f, or about 520°f, or about 530°f, or about 540°f, or about 560°f, or about 580°f, or about 600°f, or about 625°f, or about 650°f up to about 800°f, or up to about 750°f, or up to about 700°f.

The 2 nd hydrofinishing conditions typically include a lower temperature than the 1 st hydrofinishing conditions, and the particular lower temperature employed in the 2 nd hydrofinishing conditions may vary based on a number of factors as described above. Typically, the 2 nd hydrofinishing lower temperature conditions include a temperature differential as described above. As for the absolute temperature of the 2 nd hydrofinishing lower temperature conditions, the temperature may comprise one of the following: about 370 DEG F, or about 380 DEG F, up to about 390 DEG F, or up to about 410 DEG F, or up to about 430 DEG F, or up to about 455 DEG F, or up to about 460 DEG F, or up to about 465 DEG F.

In some embodiments, by employing two or more hydrofinishing stages followed by lower temperatures, base oils with low aromatics can be obtained. That is, in some embodiments, the base oil produced by the processes described herein may comprise less than about 0.9 wt.%, or less than about 0.8 wt.%, or less than about 0.7 wt.%, or less than about 0.6 wt.%, or less than about 0.5 wt.%, or less than about 0.4 wt.%, or less than about 0.3 wt.% aromatic hydrocarbon. In other embodiments, the total aromatics in the base oil produced by the present process may be at least about 30% less, or at least about 35% less, or at least about 40% less, or at least about 45% less, or at least about 50% less, than a comparable process employing a single hydrofinishing step.

Comparable processes employing a single hydrofinishing step include those such as shown in the comparable examples, wherein the single hydrofinishing step employs the same temperature in its single stage as employed in the 2 nd hydrofinishing conditions, or within 2 degrees, or within 4 degrees. That is, the temperature employed in the 1 st hydrofinishing condition is higher than both the 2 nd hydrofinishing condition and the temperature in the single hydrofinishing step, while the other conditions in the single and two or more step hydrofinishing steps are similar or identical.

Useful hydrofinishing conditions and catalysts for hydrofinishing conditions 1 and 2 and isomerization prior to hydrofinishing are described below.

Hydrofining unit

The isomerized feedstock is typically fed to one or more hydrofinishing units to produce a 1 st hydrofinishing stream and a 2 nd hydrofinishing stream for ultimately providing the desired base oil product of suitable quality and yield. Such one or more hydrofinishing steps may remove traces of any aromatics, olefins, color bodies, etc. from the base oil product. The hydrofinishing unit may comprise a hydrofinishing catalyst comprising a silica alumina support and a noble metal, typically palladium or a combination of platinum and palladium. In one embodiment, the precious metal content of the hydrofinishing catalyst may generally range from about 0.1 to about 1.0 wt%, typically from about 0.1 to about 0.6 wt%, and often from about 0.2 to about 0.5 wt%. The isomerization stream and the hydrofinishing stream may be contacted with the first catalyst and the second catalyst in the same hydrofinishing unit or separate units in series. The catalyst contacted with the isomerization stream and the catalyst contacted with the 1 st hydrofinishing stream may be the same or different catalysts.

Hydrofinishing may be performed in the presence of a hydrogenation catalyst, which may also be referred to as a hydrofinishing catalyst, as is known in the art. The hydrogenation catalyst used for hydrofinishing may, for example, comprise platinum, palladium or a combination thereof on a silica alumina support. Hydrofinishing may be performed at a temperature in the range of about 400°f to about 650°f (204 ℃ to 343 ℃) and at a pressure in the range of about 400 lbf/square inch to about 4000 lbf/square inch (2.76 to 27.58 MPa). Hydrofinishing for the production of lubricating oils is described, for example, in U.S. Pat. No. 3,852,207, the disclosure of which is incorporated herein by reference.

Within the reactor, the feed may be contacted with a hydrotreating catalyst under hydrotreating conditions. Contacting the feedstock with a hydrotreating catalyst for effective hydrogenation of aromatics in the feedstock, and in some cases removing some of the N and S containing compounds from the feedstock. By "effectively hydrogenating aromatic hydrocarbons" is meant that the hydrotreating catalyst is capable of reducing the aromatic content of the feedstock by at least about 20%. The hydrotreated feedstock may typically comprise C ₁₀₊ Normal paraffins and lightly branched isoparaffins, and typically the wax content is at least about 20%. The hydrotreated feedstock can first be contacted with a hydroisomerization catalyst under hydroisomerization dewaxing conditions to provide an isomerized stream. The hydrotreating and hydroisomerization conditions useful in the catalytic dewaxing process of the present invention are described below.

Hydrofining catalyst

In one embodiment, the catalyst system of the present invention may include hydrofinishing, which may also be referred to as hydrotreating or hydrogenation catalysts. The hydrotreating catalyst useful in the present invention may comprise a refractory inorganic oxide support and a group VIII metal. The oxide support may also be referred to herein as a binder. The support of the hydrotreating catalyst may be prepared from or contain alumina, silica/alumina, titania, magnesia, zirconia, and the like, or combinations thereof. 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-alumina, and the like.

In one embodiment, the support may comprise amorphous alumina. When a combination of silica and alumina is used, the distribution of silica and alumina in the support may be uniform or non-uniform. In some embodiments, the support may consist of an alumina gel having silica, silica/alumina or alumina matrix material dispersed therein. The support may also contain refractory materials other than alumina or silica, such as, for example, other inorganic oxides or clay particles, provided that such materials do not adversely affect the hydrogenation activity of the final catalyst or cause detrimental cracking of the feedstock.

In sub-embodiments, the silica and/or alumina will generally comprise at least about 90 wt% of the hydrotreating catalyst support, and in some embodiments, the support may be at least substantially all silica or all alumina. Regardless of the type of support material in the hydrotreating catalyst, the hydrotreating catalyst used in the process and catalyst system of the invention will typically have low acidity. Where appropriate, the acidity of the support can be reduced by treatment with alkali and/or alkaline earth cations.

Various crystalline and amorphous catalyst support materials useful in the practice of the present invention, as well as quantification of their acidity levels and methods for neutralizing acidic sites in catalyst supports, are described in co-pending, commonly assigned U.S. patent application publication No. 2011/0079440, the disclosure of which is incorporated herein by reference in its entirety.

The group VIII metal component of the hydrotreating catalyst may include platinum, palladium, or a combination thereof. In one embodiment, the hydrotreating catalyst comprises platinum and palladium, wherein the Pt to Pd ratio is in the range of about 5:1 to about 1:5, typically about 3:1 to about 1:3, and often about 1:1 to about 1:2. The group VIII metal content of the hydrotreating catalyst may generally range from about 0.01 wt.% to about 5 wt.%, typically from about 0.2 wt.% to about 2 wt.%. In one embodiment, the hydrotreating catalyst may comprise platinum in a concentration in the range of about 0.1 to about 1.0 wt% and palladium in a concentration in the range of about 0.2 to about 1.5 wt%.

In a sub-embodiment, the hydrotreating catalyst may comprise about 0.3 wt.% platinum and about 0.6 wt.% palladium. The hydrotreating catalysts of the present invention generally exhibit sulfur tolerance and high catalytic activity.

In one embodiment, the group VIII metal of the hydrotreating catalyst may be dispersed on an inorganic oxide support. Many methods for depositing platinum and/or palladium metal or compounds comprising platinum and/or palladium onto a support are known in the art; such methods include ion exchange, impregnation and co-precipitation. In one embodiment, impregnation of the support with platinum and/or palladium metal may be performed at a controlled pH. Platinum and/or palladium are typically added to the impregnating solution as metal salts such as halide salts and/or amine complexes and/or inorganic acid salts. Ammonium salts have been found to be particularly useful in the preparation of group VIII metal impregnation solutions. Other examples of metal salts that may be used include nitrates, carbonates and bicarbonates, as well as carboxylates such as acetates, citrates and formates.

Optionally, the impregnated support may be allowed to stand with the impregnating solution, for example, for a period of time in the range of about 2 to about 24 hours. After impregnating the oxide support with the group VIII metal, the impregnated support may be dried and/or calcined. After the hydrotreating catalyst has been dried and calcined, the catalyst produced may be reduced with hydrogen as is conventional in the art and put into service.

Typically, the hydrotreating catalyst may comprise from about 5% to about 20% of the total catalyst volume, and typically from about 5% to about 15% of the total catalyst volume.

Isomerisation stream, catalyst and reaction conditions

In general, the isomerization stream for the 1 st hydrofinishing step may be obtained in any convenient manner, which may vary depending on the particular conditions of the feedstock, the desired properties of the base oil, and other factors. The isomerization streams that may be used are not particularly limited and may vary depending on the desired product, isomerization, hydrofinishing and/or other conditions, the catalyst employed, and the like. The isomerization conditions and catalysts can vary widely. Typically, a hydrocarbon feedstock is contacted with a hydroisomerization catalyst under hydroisomerization dewaxing conditions to provide an isomerized stream. The isomerization stream may be produced by contacting a hydrocarbon feedstock with hydrogen and a noble metal hydroisomerization catalyst under hydroisomerization dewaxing conditions to provide an isomerization stream.

Noble metal hydroisomerization catalysts may vary, but in some embodiments comprise crystalline molecular sieve SSZ-91 and platinum. Such SSZ-91 catalysts are described in detail in U.S. Pat. No. 10,618,816, entitled "Molecular sieve SSZ-91,methods for preparing SSZ-91,and uses for SSZ-91," which is incorporated herein by reference. Similarly, hydroisomerization dewaxing conditions may vary, but in some embodiments include a temperature of about 550°f to about 700°f, and preferably 590°f to about 675°f. In some embodiments, hydroisomerization dewaxing conditions include a pressure in the range of about 15 to about 3000 lbf/square inch and preferably in the range of about 100 to about 2500 lbf/square inch.

Hydroisomerization dewaxing conditions may comprise in the presence of hydrogen for about 0.1 to about 20hr ^-1 Hydrocarbon feedstock feed rates in the LHSV range wherein the hydrogen to hydrocarbon ratio is in the range of from about 2000 to about 10,000 standard cubic feet per barrel of hydrocarbon. In other embodiments, the hydrocarbon feedstock feed rate may be from about 0.1 to about 5hr ^-1 LHSV. In some embodiments, the hydrogen to hydrocarbon ratio may be from about 2500 to about 5000 standard cubic feet per barrel of hydrocarbon.

The hydroisomerization catalyst may comprise, for example, a 1-D, 10-ring molecular sieve and a group VIII metal substantially as described above under "hydroisomerization catalyst". Hydroisomerization catalysts may be selective for the isomerization of normal paraffins in the feedstock such that the feedstock components are preferentially isomerized rather than cracked.

Hydroisomerization catalyst

In one embodiment, the process of the present invention uses a hydroisomerization catalyst that is selective for the isomerization of normal paraffins in the hydrocarbon feed. Useful hydroisomerization catalysts may comprise a molecular sieve and a group VIII metal. In one embodiment, the molecular sieve of the hydroisomerization catalyst may comprise a 1-D, 10-ring molecular sieve. The group VIII metal of the first hydroisomerization catalyst and the second hydroisomerization catalyst may comprise platinum, palladium, or a combination thereof. In one embodiment, the hydroisomerization catalyst may comprise from about 0.1 to about 1.5 wt.% of the group VIII metal, typically from about 0.2 to about 1.0 wt.%, and typically from about 0.325 to about 1.0 wt.% of the group VIII metal. In one embodiment, the hydroisomerization catalyst may further comprise a metal modifier selected from the group consisting of: mg, ca, sr, ba, K, la, pr, nd, cr, and combinations thereof.

Typically, the hydroisomerization catalyst will also comprise a support or binder. The support may comprise a refractory inorganic oxide. Suitable inorganic oxide supports for the hydroisomerization catalyst include silica, alumina, titania, magnesia, zirconia, silica-alumina, silica-magnesia, silica-titania, and the like, as well as combinations thereof. The hydroisomerization catalyst may comprise about 5 to about 95 weight percent or more of the molecular sieve component, typically about 15 to about 85 weight percent of the molecular sieve, and typically about 25 to about 75 weight percent of the molecular sieve. Generally, it is advantageous for economic reasons to minimize the molecular sieve component, provided that the catalyst maintains the desired level of activity and selectivity. The hydroisomerization catalyst may comprise from about 0 to about 95 wt.% and more typically from about 5 to about 90 wt.% of the support material.

In an exemplary catalyst system for dewaxing a hydrocarbon feedstock in accordance with the process of this invention, each hydroisomerization catalyst may comprise a 1-D, 10-ring molecular sieve and a group VIII metal. The molecular sieve of the hydroisomerization catalyst may comprise a mesoporous zeolite, such as a zeolite having a pore size in the range of about 0.39nm to about 0.7 nm. In one embodiment, each of the hydroisomerization catalysts may further comprise about 0.325 wt.% to about 1 wt.% platinum.

Examples of molecular sieves that can be used to formulate hydroisomerization catalysts include molecular sieves of AEL framework-type code, such as SAPO-11, SAPO-31, SM-3, SM-6; and zeolite-type materials of MTT or TON code. Molecular sieves for MTT codes include ZSM-23, SSZ-32, EU-13, ISI-4 and KZ-1. Molecular sieves of TON codes useful in the practice of the present invention include Theta-1, ISI-1, KZ-2, NU-10 and ZSM-22. The parameters of MTT and TON type molecular sieves are further described in Atlas of Zeolite Framework Types published by International Zeolite Association (IZA). In one embodiment, the hydroisomerization catalyst contains zeolite SSZ-32. In one embodiment, the hydroisomerization catalyst contains SSZ-32. The process of the present invention is not limited to any particular hydroisomerization catalyst formulation.

Metal loading of catalyst

In one embodiment, the hydroisomerization catalyst may also comprise one or more metal modifiers. In general, the metal modifier may be selected from the group consisting of: mg, ca, sr, ba, K, la, pr, nd, cr, and combinations thereof. In a sub-embodiment, the metal modifier may comprise Mg. As a non-limiting example, the hydroisomerization catalyst may comprise a 1-D, 10-ring molecular sieve, such as SSZ-32; group VIII noble metals such as platinum; and in some embodiments, a metal modifier, such as magnesium. In one embodiment, the metal modified catalyst of the present invention may comprise from about 0.5 to about 3.5 wt% Mg or other metal modifier, typically from about 0.5 to about 2.5 wt%, and typically from about 0.9 to about 2.5 wt% Mg or other metal modifier.

In formulating the catalyst or catalyst system for use in the dewaxing process of the present invention, the mixture of molecular sieve and oxide binder can be formed into particles or extrudates having a wide range of physical shapes and sizes. In one embodiment, the extrudate or particle may be dried and calcined prior to metal loading. Calcination may be performed at temperatures typically in the range of about 390°f to about 1100°f (199 ℃ to 593 ℃) for a period of time in the range of about 0.5 to about 5 hours or more. The calcined extrudate or formed particles may then be loaded with at least one metal modifier selected from the group consisting of: ca. Cr, mg, la, na, pr, sr, K, nd, and combinations thereof. While not being bound by theory, such metals can effectively reduce the number of acid sites on the metal-modified hydroisomerization catalyst molecular sieve, thereby increasing the selectivity of the catalyst to isomerization (versus cracking) of normal paraffins in the feed. The loading of the modified metal on the catalyst may be accomplished by techniques known in the art, such as by impregnation or ion exchange. Ion exchange techniques typically involve contacting the extrudate or particles with a solution containing a salt of the desired metal cation. A variety of metal salts may be used in this regard, such as halides, nitrates and sulfates. After contact with the salt solution of the desired metal cation, the extrudate or particle may be dried, for example, at a temperature in the range of about 150°f to about 800°f (66 ℃ to 427 ℃). The extrudate or particles may then be further loaded with a group VIII metal component of the catalyst.

In one embodiment, the molecular sieve or catalyst of the present invention may be co-impregnated with a modifying metal and a group VIII metal. After loading the group VIII metal and the modifying metal, the catalyst may be calcined in air or an inert gas at a temperature in the range of about 500°f to about 900°f (260 ℃ to 482 ℃). The preparation of molecular sieve catalysts comprising metal modifiers is disclosed in commonly assigned U.S. patent No. 7,141,529 and U.S. patent application publication No. 2008/0083657, the disclosures of each of which are incorporated herein by reference in their entirety.

Isomerization and hydrofining reaction conditions

The conditions under which the process of the present invention is conducted will typically include a temperature in the range of about 390°f to about 800°f (199 ℃ to 427 ℃). In one embodiment, the hydroisomerization dewaxing conditions include a temperature in the range of about 550°f to about 700°f (288 ℃ to 371 ℃). In another embodiment, the temperature may be in the range of about 590°f to about 675°f (310 ℃ to 357 ℃). The pressure may be in the range of about 15 to about 3000 pounds force per square inch (0.10 to 20.68 MPa), and typically in the range of about 100 to about 2500 pounds force per square inch (0.69 to 17.24 MPa).

Typically, during the dewaxing process of the present invention, the feed rate to the catalyst system/reactor can be in the range of about 0.1 to about 20hr ^-1 LHSV, and typically about 0.1 to about 5hr ^-1 LHSV range. Generally, the dewaxing process of the present invention is performed in the presence of hydrogen. Typically, the hydrogen to hydrocarbon ratio may be in the range of about 2000 to about 10,000 standard cubic feet per barrel of hydrocarbon, and typically about 2500 to about 5000 standard cubic feet per barrel of hydrocarbon.

The above conditions may apply to the hydrotreating conditions of the hydrotreating zone and the hydroisomerization conditions of the hydroisomerization zone. The reactor temperature and other process parameters may vary depending on factors such as the nature of the hydrocarbon feedstock used and the desired characteristics (e.g., pour point, cloud point, VI) and yield of the base oil product.

Base oil product

The base oil product may have a pour point of not greater than about-9 ℃, typically not greater than about-12 ℃, and typically not greater than about-14 ℃. The base oil product can have a cloud point of no greater than about-5 ℃, typically no greater than about-7 ℃, and typically no greater than about-12 ℃. The base oil product may have a pour-haze differential of no more than about 7 ℃, typically no more than about 5 ℃, and typically no more than about 3 ℃. In one embodiment, a base oil product having the above properties can be obtained in a yield of at least about 89%.

In some embodiments, the process of the present invention provides high value, high quality lubricating oils in good yields from low value waxy hydrocarbon feedstocks. The lubricating oil may have a pour point of less than about-9 ℃, typically less than about-12 ℃, and often less than about-14 ℃, for example as measured by ASTM D97. In one embodiment, the lube product may have a pour point in the range of about-10 ℃ to about-30 ℃. The product may have a viscosity in the range of 3 to 30 centistokes at 100 ℃, and a VI in the range of about 95 to about 170, as measured by ASTM D445.

Feed for base oil production

The present invention may use a variety of hydrocarbon feedstocks including whole crude oil (whole crude petroleum), atmospheric residuum (reduced crudes), vacuum distillation column residuum (vacuum tower residua), cycle oil, synthetic crude oil, gasoline, vacuum gasoline, foot oil, fischer-Tropsch derived waxes (Fischer-Tropsch Tropsch derived wax), and the like. In one embodiment, the hydrocarbon feedstock may be described as a waxy feed having a pour point typically above about 0 ℃ and which, upon cooling to about 0 ℃, tends to solidify, precipitate, or otherwise form solid particles. Linear n-paraffins having 16 or more carbon atoms (alone or with slightly branched paraffins) may be referred to herein as waxes. The feedstock will typically be C, which typically boils above about 350F (177 ℃) ₁₀₊ Raw materials.

In one embodiment, the feedstock may comprise a heavy feed. The term "heavy feed" may be used herein to refer to hydrocarbon feedstocks in which at least about 80% of the components have boiling points above about 900°f (482 ℃). Examples of heavy feeds suitable for practicing the present invention include heavy neutral (600N) and bright oil.

In one embodiment, the hydrocarbon feedstock of the present invention may generally have a pour point of greater than 0 ℃, and in some embodiments greater than about 20 ℃. In contrast, the base oil product of the process of the present invention typically has a pour point of less than 0 ℃, typically less than about-12 ℃, and often less than about-14 ℃.

In one embodiment, the feedstock employed in the process of the present invention may be a waxy feed containing greater than about 20% wax, greater than about 50% wax, or even greater than about 70% wax. More typically, the feed will contain from about 5% to about 30% wax. As used herein, the term "waxy hydrocarbon feedstock" may include vegetable waxes and animal derived waxes in addition to petroleum derived waxes.

According to one aspect of the invention, a wide range of feeds can be used to produce lubricant base oils with good performance characteristics including low aromatics, low pour points, low cloud points, low haze-slip and high viscosity index in high yields. The quality and yield of the lubricating oil base oil products of the present invention may depend on a number of factors, including, but not limited to, the hydrofinishing steps and conditions described herein.

Examples

Comparative example

The comparative example uses dewaxing 101 and one stage hydrofinishing 102 as shown in figure 1, followed by product separation systems 201, 202 and 203 operation. A noble metal hydroisomerization catalyst is contained in 101. The noble metal catalyst is formed by compounding microcrystalline SSZ-91 and platinum. Reactor 2, 102 (one stage hydrofinishing), is loaded with a Pd/Pt catalyst to further improve lube product quality.

Legend to fig. 1: 101-dewaxing; 102-one-stage hydrofining; 201-a high pressure separator; 202-a distillation system; 203-debutanizer column

This process configuration was evaluated using a "heavy neutral" feed and the properties are described in table 1 below. Feed and reaction conditions are described in WO2012/005980, which is incorporated herein by reference.

TABLE 1 feed Properties

The reaction was performed in a micro-cell having the described configuration and operated at 2100 lbf/square inch total pressure. The catalyst was activated by standard reduction procedures prior to introduction of the feed. HN feed was at 1.2hr ^-1 Is passed through a hydrodewaxing reactor and then hydrofinished at 102. The hydrogen to oil ratio was about 3000 standard cubic feet per barrel. The base oil product is separated from the fuel by a distillation section. Determining the aromatic hydrocarbon content of the product.

101 is operated at 600-650°f to convert wax molecules to achieve product pour point targets, and 201 is operated at 450°f to improve product quality. The results are shown in table 2 below.

Example 1

Example 1 consists of dewaxing 101, two stage hydrofinishing 102 and 103 followed by product separation systems 201, 202 and 203 as shown in figure 2. Noble metal hydroisomerization catalysts are contained in the stage 1 reactor. After passing through the dewaxing reactor, the effluent is first treated at 102 and then sent to 103 for further refinement. 102 and 103 are both loaded with Pd/Pt catalysts to saturate aromatics and further remove impurities. The hydrogen to oil ratio was about 3000 standard cubic feet per barrel. The lube oil product is separated from the fuel by a distillation section. Determining the aromatic hydrocarbon content of the product.

Legend to fig. 2: 101-dewaxing; 102-1 st stage hydrofining; 103-2 nd stage hydrofining; 201-a high pressure separator; 202-a distillation system; 203-debutanizer column

In example 1, 101 was operated at 600-650°f to convert wax molecules in order to achieve product pour point targets. 102 at-500°f and 103 at 450°f to saturate the monocyclic and polycyclic aromatic hydrocarbons in order to improve product quality and stability.

Examples 2-9 below were performed in the same manner, except that the temperature was changed as described below. The results are shown in table 2 below and fig. 3.

Example 2:

on the catalyst and process system of example 1, 102 was operated at-510°f and 103 was operated at 400°f.

Example 3:

on the catalyst and process system of example 1, 102 was operated at-550°f and 103 was operated at 400°f.

Example 4:

on the catalyst and process system of example 1, 102 was operated at-550°f and 103 was operated at 370°f.

Example 5:

on the catalyst and process system of example 1, 102 was operated at-580°f and 103 was operated at 380°f.

Example 6:

on the catalyst and process system of example 1, 102 was operated at 600°f and 103 was operated at 380°f.

Example 7:

on the catalyst and process system of example 1, 102 was operated at-625°f and 103 was operated at 380°f.

Example 8:

on the catalyst and process system of example 1, 102 was operated at-625°f and 103 was operated at 410°f.

Example 9:

on the catalyst and process system of example 1, 102 was operated at-650°f and 103 was operated at 410°f.

Table 2-results of comparative examples and examples 2-9

System and method for controlling a system

The systems employed in the above processes and examples are also contemplated in the present application and are further described in the numbered embodiments below.

1. A system for producing a low aromatic base oil, comprising:

an isomerization zone comprising a noble metal SSZ-91 hydroisomerization catalyst for producing an SSZ-91 isomerized stream;

a first hydrofinishing zone for contacting the SSZ-91 isomerization stream with a noble metal hydrofinishing catalyst under 1 st hydrofinishing conditions to provide a 1 st hydrofinishing stream; and

a second hydrofinishing zone for contacting the 1 st hydrofinishing stream with a second noble metal hydrofinishing catalyst under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream, wherein the 2 nd hydrofinishing conditions comprise a lower temperature than the 1 st hydrofinishing conditions.

2. The system of embodiment 1, wherein the base oil produced by the system comprises less than 0.9 wt% aromatics.

3. The system of embodiment 1, wherein the base oil produced by the system comprises a pour point of about-5 ℃ to about-20 ℃.

4. The system of embodiment 1, wherein the total aromatics in the base oil produced by the system is at least about 30% less than a comparable system employing a single hydrofinishing step.

5. The system of embodiment 1, wherein the SSZ-91 isomerization stream is produced by contacting a hydrocarbon feedstock under hydroisomerization dewaxing conditions with hydrogen and a noble metal SSZ-91 hydroisomerization catalyst to provide the isomerization stream.

6. The system of embodiment 5, wherein the noble metal SSZ-91 hydroisomerization catalyst comprises crystalline molecular sieve SSZ-91 and platinum.

7. The system of embodiment 1, wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst each comprise a silica alumina support and a noble metal selected from palladium, platinum, or a combination thereof.

8. The system of embodiment 1, wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst are the same.

9. The system of embodiment 1, wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst each comprise a noble metal content of about 0.1 to about 1.0 wt%.

10. The system of embodiment 1, wherein the 1 st hydrofinishing conditions comprise a temperature of about 475°f to about 700°f.

11. The system of embodiment 1, wherein the 2 nd hydrofinishing conditions comprise a temperature of about 370°f to about 475°f.

12. The system of embodiment 5, wherein the hydroisomerization dewaxing conditions comprise a temperature of about 550°f to about 700°f.

13. The system of embodiment 5, wherein the hydroisomerization dewaxing conditions comprise a pressure in the range of about 15 to about 3000 lbf/square inch.

14. The system of embodiment 5, wherein the hydroisomerization dewaxing conditions comprise in the presence of hydrogen for about 0.1 to about 20hr ^-1 Hydrocarbon feedstock feed rates in the LHSV range wherein the hydrogen to hydrocarbon ratio is in the range of from about 2000 to about 10,000 standard cubic feet per barrel of hydrocarbon.

15. The system of embodiment 1, wherein the 1 st hydrofinishing conditions and the 2 nd hydrofinishing conditions comprise a pressure in the range of about 15 to about 3000 lbf/square inch.

16. The system of embodiment 1, wherein the 1 st hydrofinishing conditions and the 2 nd hydrofinishing conditions comprise about 0.1 to about 20hr ^-1 Hydrofinishing stream feed rate 1 and hydrofinishing stream feed rate 2 for LHSV.

17. A system for producing a low aromatic base oil, comprising:

an isomerization zone for contacting a hydrocarbon feedstock under hydroisomerization dewaxing conditions with hydrogen and a catalyst comprising crystalline molecular sieve SSZ-91 and platinum to provide an isomerized stream;

a first hydrofinishing zone for contacting the isomerised stream under 1 st hydrofinishing conditions with a catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum or a combination thereof, to provide a 1 st hydrofinished stream, wherein the catalyst comprises a noble metal content of from about 0.1 to about 0.6 wt%; and

a second hydrofinishing zone for contacting the 1 st hydrofinishing stream with a catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum, or a combination thereof, under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream, wherein the catalyst comprises a noble metal content of about 0.1 to about 0.6 wt%, wherein the 2 nd hydrofinishing conditions comprise a lower temperature than the 1 st hydrofinishing conditions, and wherein the base oil produced by the system comprises at least about 40 wt% less aromatic hydrocarbons than a comparable system employing a single hydrofinishing step.

18. The system of embodiment 17, wherein the base oil produced by the system comprises less than 0.8 wt% aromatics.

19. The system of embodiment 17, wherein the base oil produced by the system comprises a pour point of no more than about-12 ℃.

20. The system of embodiment 17, wherein the base oil product is obtained in a yield of at least about 85%.

21. The system of embodiment 17, wherein the 2 nd hydrofinishing condition comprises a temperature of about 50 to about 450°f below the 1 st hydrofinishing condition.

The present disclosure is not to be limited by the specific embodiments described in this disclosure, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent. Functionally equivalent methods and systems within the scope of the disclosure, in addition to those enumerated herein, may be apparent from the foregoing representative descriptions. Such modifications and variations are intended to fall within the scope of the appended representative claims. The present disclosure is limited only by the terms of the appended representative claims, along with the full scope of equivalents to which such representative claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

The foregoing description and its associated embodiments have been presented for the purpose of illustration only. It is not intended to be exhaustive and does not limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed embodiments as may be apparent to those of ordinary skill in the art from the foregoing description. For example, the steps described need not be performed in the same order as discussed or with the same degree of separation. Also, individual steps may be omitted, repeated, or combined as desired to achieve the same or similar objectives. The invention is therefore not limited to the embodiments described above, but instead is defined by the appended claims in accordance with their full scope of equivalents.

In the foregoing specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.

Claims

1. A process for producing a low aromatic base oil comprising:

Contacting the SSZ-91 isomerized stream with a noble metal hydrofinishing catalyst under hydrofinishing conditions 1 to provide a hydrofinishing stream 1; and

contacting the 1 st hydrofinishing stream with a second noble metal hydrofinishing catalyst under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream;

wherein the 2 nd hydrofinishing conditions comprise a lower temperature than the 1 st hydrofinishing conditions.

2. The process of claim 1, wherein the base oil produced by the process comprises less than 0.9 wt% aromatics.

3. The method of claim 1 wherein the base oil produced by the method comprises a pour point of about-5 ℃ to about-20 ℃.

4. The process of claim 1 wherein the total aromatics in the base oil produced by said process are at least about 30% less than a comparable process employing a single hydrofinishing step.

5. The process of claim 1, wherein the SSZ-91 isomerization stream is produced by contacting a hydrocarbon feedstock under hydroisomerization dewaxing conditions with hydrogen and a noble metal SSZ-91 hydroisomerization catalyst to provide the isomerization stream.

6. The process of claim 5 wherein the noble metal SSZ-91 hydroisomerization catalyst comprises crystalline molecular sieve SSZ-91 and platinum.

7. The process of claim 1, wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst each comprise a silica alumina support and a noble metal selected from palladium, platinum, or a combination thereof.

8. The process of claim 1 wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst are the same.

9. The process of claim 1 wherein the noble metal hydrofinishing catalyst and the second noble metal hydrofinishing catalyst each comprise a noble metal content of about 0.1 to about 1.0 wt%.

10. The method of claim 1, wherein the 1 st hydrofinishing conditions comprise a temperature of about 475°f to about 700°f.

11. The method of claim 1, wherein the 2 nd hydrofinishing conditions comprise a temperature of about 370°f to about 475°f.

12. The method of claim 5, wherein the hydroisomerization dewaxing conditions comprise a temperature of about 550°f to about 700°f.

13. The process of claim 5, wherein the hydroisomerization dewaxing conditions comprise a pressure in the range of about 15 to about 3000 lbf/square inch.

14. The process of claim 5, wherein the hydroisomerization dewaxing conditions comprise in the presence of hydrogen for about 0.1 to about 20hr ^-1 Hydrocarbon feedstock feed rates in the LHSV range wherein the hydrogen to hydrocarbon ratio is in the range of from about 2000 to about 10,000 standard cubic feet per barrel of hydrocarbon.

15. The method of claim 1, wherein the 1 st hydrofinishing conditions and the 2 nd hydrofinishing conditions comprise a pressure in the range of about 15 to about 3000 lbf/square inch.

16. The process of claim 1 wherein the 1 st hydrofinishing conditions and the 2 nd hydrofinishing conditions comprise about 0.1 to about 20hr ^-1 Hydrofinishing stream feed rate 1 and hydrofinishing stream feed rate 2 for LHSV.

17. A process for producing a low aromatic base oil comprising:

contacting a hydrocarbon feedstock under hydroisomerization dewaxing conditions with hydrogen and a catalyst comprising crystalline molecular sieve SSZ-91 and platinum to provide an isomerized stream;

contacting the isomerized stream under 1 st hydrofinishing conditions with a catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum, or combinations thereof, wherein the catalyst comprises a noble metal content of from about 0.1 to about 0.6 weight percent, to provide a 1 st hydrofinished stream; and

contacting the 1 st hydrofinishing stream with a catalyst under 2 nd hydrofinishing conditions to provide a 2 nd hydrofinishing stream, the catalyst comprising a silica alumina support and a noble metal selected from palladium, platinum, or a combination thereof, wherein the catalyst comprises a noble metal content of about 0.1 to about 0.6 wt%;

Wherein the 2 nd hydrofinishing conditions comprise a lower temperature than the 1 st hydrofinishing conditions; and is also provided with

Wherein the base oil produced by the process comprises at least about 40 wt.% less aromatic hydrocarbons than a comparable process employing a single hydrofinishing step.

18. The method of claim 17, wherein the base oil produced by the method comprises less than 0.8 wt% aromatics.

19. The method of claim 17 wherein the base oil produced by the method comprises a pour point of no more than about-12 ℃.

20. The process of claim 17 wherein the base oil product is obtained in a yield of at least about 85%.

21. The method of claim 17, wherein the 2 nd hydrofinishing condition comprises a temperature of about 50 to about 450°f below the 1 st hydrofinishing condition.