Patent Application
20220325192
The invention concerns a process for improving base oil yields by combining an atmospheric resid feedstock with a base oil feedstock to form a combined feedstream and forming a base oil product therefrom via hydroprocessing.
High quality lubricating base oils, such as those having a viscosity index (VI) of 120 or greater (Group II and Group III), may generally be produced from high-boiling point vacuum distillates, such as vacuum gas oils (VGO), by hydrocracking to raise VI, followed by catalytic dewaxing to lower pour point and cloud point, and followed by hydrofinishing to saturate aromatics and improve stability. In hydrocracking, high-boiling molecules are cracked to lower-boiling molecules which raises VI but also lowers the viscosity. In order to make a high VI and high viscosity grade base oil at high yield, the hydrocracker feed must contain a certain quantity of high-boiling molecules. Typically, VGOs are limited in their ability to recover very high-boiling molecules from atmospheric resid (AR) in a vacuum column because of practical limits on temperature and pressure. One possible means of feeding higher-boiling molecules to the hydrocracker is to feed the AR directly, but such an approach is not normally possible or workable because the AR usually contains materials that are extremely harmful to the hydrocracker catalyst, including, e.g., nickel, vanadium, micro-carbon residue (MCR) and asphaltenes. These materials shorten the hydrocracker catalyst life to an unacceptable degree, making the use of such feeds impracticable.
One approach to using difficult whole crude and other intermediate feeds for making base oils is to first process the feed, such as AR or vacuum resid (VR), in a solvent deasphalting (SDA) unit. Such treatment is usually necessary to separate the bulk of undesirable materials while producing a deasphalted oil (DAO) of acceptable hydrocracker feed quality. The very high capital requirements and high operating cost of such SDA units, and the overall process approach, make them undesirable alternatives, however. Other approaches that attempt to minimize or eliminate the need for solvent deasphalting steps have been implemented but have not provided a clear benefit in terms of cost or other process improvements.
The production of Group III base oils and finished motor oils has usually required the use of expensive and supply-limited viscosity index improvers such as polyalphaolefins, or other expensive processing techniques, such as the use of gas-to-liquid (GTL) feedstocks or, e.g., through multi-hydrocracking processing of mineral oils. The production of Group III base oils also generally requires high quality feedstock(s) and processing at high conversion to meet a VI targets at the expense of product yield. Despite continuing industry efforts, however, a comparatively inexpensive and suitable feedstock, and a simplified process for making such products, remains to be developed and commercialized.
Despite the progress in producing base oils from differing and challenging feeds, a continuing need exists for improved processes to both utilize different feedstocks and to increase the yield of valuable base oil products.
The present invention is directed to a process for making a base oil product, particularly a light grade base oil product and a heavy grade base oil product through hydroprocessing of a base oil feedstream. While not necessarily limited thereto, one of the goals of the invention is to provide increased base oil yield of a heavy grade base oil product and to the production of Group II and/or Group III/III+ base oils.
In general, a first process according to the invention comprises making a base oil by combining an atmospheric resid feedstock and a base oil feedstock to form a base oil feedstream; contacting the base oil feedstream with a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked product; separating the hydrocracked product into a gaseous fraction and a liquid fraction; contacting the liquid fraction with a dewaxing catalyst under hydroisomerization conditions, to produce a dewaxed product; and, optionally, contacting the dewaxed product with a hydrofinishing catalyst under hydrofinishing conditions to produce a hydrofinished dewaxed product.
The invention also relates to a method for modifying a base oil process through the addition of an atmospheric resid feedstock to a base oil feedstock in a conventional base oil process that comprises subjecting a base oil feedstream to hydrocracking and dewaxing steps to form a dewaxed product comprising a light product and a heavy product. As such, the modified base oil process comprises combining an atmospheric resid feedstock and a base oil feedstock to form a base oil feedstream; contacting the base oil feedstream with a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked product; separating the hydrocracked product into at least a gaseous fraction and a liquid fraction; contacting the liquid fraction with a dewaxing catalyst under hydroisomerization conditions, to produce a dewaxed product; and, optionally, contacting the dewaxed product with a hydrofinishing catalyst under hydrofinishing conditions to produce a hydrofinished dewaxed product.
A second process according to the invention comprises making a base oil having a viscosity index of 120 or greater by contacting a base oil feedstock having a viscosity index of about 100 or greater that comprises a medium vacuum gas oil (MVGO) having a front end cut point of about 700° F. or greater and a back end cut point of about 900° F. or less with a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked product; separating the hydrocracked product into a gaseous fraction and a liquid fraction; dewaxing of the liquid fraction to produce a dewaxed product; and optionally, hydrofinishing of the dewaxed product to produce a hydrofinished dewaxed product.
The invention further relates to a combined process for making a base oil product from a base oil feedstock that combines the first process and the second process to make base oils meeting Group II and/or Group III/III+ specifications. The combined process generally provides for making a base oil from a base oil feedstock, or a fraction thereof, and includes the use of an atmospheric resid fraction from a base oil feedstock, or a fraction thereof; separation of the base oil feedstock, or a fraction thereof, and/or the base oil atmospheric resid fraction into a narrow vacuum gas oil cut-point fraction having a front end cut point of about 700° F. or greater and a back end cut point of about 900° F. or less to form a medium vacuum gas oil (MVGO) fraction and a residual heavy VGO (HHVGO) fraction; and use of the HHVGO fraction as the atmospheric resid feedstock in the first process; and/or use of the MVGO fraction as the base oil feedstock in the second process.
The scope of the invention is not limited by any representative figures accompanying this disclosure and is to be understood to be defined by the claims of the application.
Although illustrative embodiments of one or more aspects are provided herein, the disclosed processes may be implemented using any number of techniques. The disclosure is not limited to the illustrative or specific embodiments, drawings, and techniques illustrated herein, including any exemplary designs and embodiments illustrated and described herein, and may be modified within the scope of the appended claims along with their full scope of equivalents.
Unless otherwise indicated, the following terms, terminology, and definitions are applicable to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition from the IUPAC Compendium of Chemical Terminology, 2nd ed (1997), may be applied, provided that definition does not conflict with any other disclosure or definition applied herein, or render indefinite or non-enabled any claim to which that definition is applied. To the extent that any definition or usage provided by any document incorporated herein by reference conflicts with the definition or usage provided herein, the definition or usage provided herein is to be understood to apply.
“API Base Oil Categories” are classifications of base oils that meet the different criteria shown in Table 1:
“API gravity” refers to the gravity of a petroleum feedstock or product relative to water, as determined by ASTM D4052-11 or ASTM D1298.
“ISO-VG” refers to the viscosity classification that is recommended for industrial applications, as defined by ISO3448:1992.
“Viscosity index” (VI) represents the temperature dependency of a lubricant, as determined by ASTM D2270-10(E2011).
“Aromatic Extraction” is part of a process used to produce solvent neutral base oils. During aromatic extraction, vacuum gas oil, deasphalted oil, or mixtures thereof are extracted using solvents in a solvent extraction unit. The aromatic extraction creates a waxy raffinate and an aromatic extract, after evaporation of the solvent.
“Atmospheric resid” or “atmospheric residuum” (AR) is a product of crude oil distillation at atmospheric pressure in which volatile material has been removed during distillation. AR cuts are typically derived at 650° F. up to a 680° F. cut point.
“Vacuum gas oil” (VGO) is a byproduct of crude oil vacuum distillation that can be sent to a hydroprocessing unit or to an aromatic extraction for upgrading into base oils. VGO generally comprises hydrocarbons with a boiling range distribution between 343° C. (649° F.) and 538° C. (1000° F.) at 0.101 MPa.
“Deasphalted oil” (DAO) generally refers to the residuum from a vacuum distillation unit that has been deasphalted in a solvent deasphalting process. Solvent deasphalting in a refinery is described in J. Speight, Synthetic Fuels Handbook, ISBN 007149023X, 2008, pages 64, 85-85, and 121.
“Treatment,” “treated,” “upgrade,” “upgrading” and “upgraded,” when used in conjunction with an oil feedstock, describes a feedstock that is being or has been subjected to hydroprocessing, or a resulting material or crude product, having a reduction in the molecular weight of the feedstock, a reduction in the boiling point range of the feedstock, a reduction in the concentration of asphaltenes, a reduction in the concentration of hydrocarbon free radicals, and/or a reduction in the quantity of impurities, such as sulfur, nitrogen, oxygen, halides, and metals.
“Solvent Dewaxing” is a process of dewaxing by crystallization of paraffins at low temperatures and separation by filtration. Solvent dewaxing produces a dewaxed oil and slack wax. The dewaxed oil can be further hydrofinished to produce base oil.
“Hydroprocessing” refers to a process in which a carbonaceous feedstock is brought into contact with hydrogen and a catalyst, at a higher temperature and pressure, for the purpose of removing undesirable impurities and/or converting the feedstock to a desired product. Examples of hydroprocessing processes include hydrocracking, hydrotreating, catalytic dewaxing, and hydrofinishing.
“Hydrocracking” refers to a process in which hydrogenation and dehydrogenation accompanies the cracking/fragmentation of hydrocarbons, e.g., converting heavier hydrocarbons into lighter hydrocarbons, or converting aromatics and/or cycloparaffins (naphthenes) into non-cyclic branched paraffins.
“Hydrotreating” refers to a process that converts sulfur and/or nitrogen-containing hydrocarbon feeds into hydrocarbon products with reduced sulfur and/or nitrogen content, typically in conjunction with hydrocracking, and which generates hydrogen sulfide and/or ammonia (respectively) as byproducts.
“Catalytic dewaxing”, or hydroisomerization, refers to a process in which normal paraffins are isomerized to their more branched counterparts in the presence of hydrogen and over a catalyst.
“Hydrofinishing” refers to a process that is intended to improve the oxidation stability, UV stability, and appearance of the hydrofinished product by removing traces of aromatics, olefins, color bodies, and solvents. As used in this disclosure, the term UV stability refers to the stability of the hydrocarbon being tested when exposed to UV light and oxygen. Instability is indicated when a visible precipitate forms, usually seen as Hoc or cloudiness, or a darker color develops upon exposure to ultraviolet light and air. A general description of hydrofinishing may be found in U.S. Pat. Nos. 3,852,207 and 4,673,487.
The term “Hydrogen” or “hydrogen” refers to hydrogen itself, and/or a compound or compounds that provide a source of hydrogen.
“Cut point” refers to the temperature on a True Boiling Point (TBP) curve at which a predetermined degree of separation is reached.
“TBP” refers to the boiling point of a hydrocarbonaceous feed or product, as determined by Simulated Distillation (SimDist) by ASTM D2887-13.
“Hydrocarbonaceous”, “hydrocarbon” and similar terms refer to a compound containing only carbon and hydrogen atoms. Other identifiers may be used to indicate the presence of particular groups, if any, in the hydrocarbon (e.g., halogenated hydrocarbon indicates the presence of one or more halogen atoms replacing an equivalent number of hydrogen atoms in the hydrocarbon).
“Group IIB” or “Group IIB metal” refers to zinc (Zn), cadmium (Cd), mercury (Hg), and combinations thereof in any of elemental, compound, or ionic form.
“Group IVA” or” “Group IVA metal” refers to germanium (Ge), tin (Sn) or lead (Pb), and combinations thereof in any of elemental, compound, or ionic form.
“Group V metal” refers to vanadium (V), niobium (Nb), tantalum (Ta), and combinations thereof in their elemental, compound, or ionic form.
“Group VIB” or “Group VIB metal” refers to chromium (Cr), molybdenum (Mo), tungsten (W), and combinations thereof in any of elemental, compound, or ionic form.
“Group VIII” or “Group VIII metal” refers to iron (Fe), cobalt (Co), nickel (Ni), ruthenium (Ru), rhenium (Rh), rhodium (Ro), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt), and combinations thereof in any of elemental, compound, or ionic form.
The term “support”, particularly as used in the term “catalyst support”, refers to conventional materials that are typically a solid with a high surface area, to which catalyst materials are affixed. Support materials may be inert or participate in the catalytic reactions, and may be porous or non-porous. Typical catalyst supports include various kinds of carbon, alumina, silica, and silica-alumina, e.g., amorphous silica aluminates, zeolites, alumina-boria, silica-alumina-magnesia, silica-alumina-titania and materials obtained by adding other zeolites and other complex oxides thereto.
“Molecular sieve” refers to a material having uniform pores of molecular dimensions within a framework structure, such that only certain molecules, depending on the type of molecular sieve, have access to the pore structure of the molecular sieve, while other molecules are excluded, e.g., due to molecular size and/or reactivity. Zeolites, crystalline aluminophosphates and crystalline silicoaluminophosphates are representative examples of molecular sieves.
W220 and W600 refer to waxy medium and heavy Group II base oil product grades, with W220: referring to a waxy medium base oil product having a nominal viscosity of about 6 cSt at 100° C., and W600: referring to a waxy heavy base oil product having a nominal viscosity of about 12 cSt at 100° C. Following dewaxing, typical test data for Group II base oils are as follows:
In this disclosure, while compositions and methods or processes are often described in terms of “comprising” various components or steps, the compositions and methods may also “consist essentially of” or “consist of” the various components or steps, unless stated otherwise.
The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of “a transition metal” or “an alkali metal” is meant to encompass one, or mixtures or combinations of more than one, transition metal or alkali metal, unless otherwise specified.
All numerical values within the detailed description and the claims herein are modified by “about” or “approximately” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.
In one aspect, the present invention is a process for making a base oil product, comprising
combining an atmospheric resid feedstock and a base oil feedstock to form a base oil feedstream;
contacting the base oil feedstream with a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked product;
separating the hydrocracked product into a gaseous fraction and a liquid fraction;
contacting the liquid fraction with a dewaxing catalyst under hydroisomerization conditions, to produce a dewaxed product; and
optionally, contacting the dewaxed product with a hydrofinishing catalyst under hydrofinishing conditions to produce a hydrofinished dewaxed product.
The base oil feedstock generally meets one or more of the following property conditions:
API gravity in the range of 15-40 or 15-30 or 15-25, or at least 15, or at least 17, optionally, less than the atmospheric resid feedstock;
VI in the range of 30-90 or 40-90 or 50-90 or 50-80, optionally, less than the VI of the atmospheric resid feedstock;
viscosity at 100° C. in the range of 3-30 cSt or 3-25 cSt or 3-20 cSt, or at least 3 cSt, or at least 4 cSt;
viscosity at 70° C. in the range of 5-25 cSt or 5-20 cSt or 5-15 cSt, or at least 5 cSt, or at least 6 cSt;
hot C7 asphaltene content in the range of 0.01-0.3 wt. % or 0.01-0.2 wt. % or 0.02-0.15 wt. %, or less than 0.3 wt. %, or less than 0.2 wt. %;
wax content in the range of 5-40 wt. % or 5-30 wt. % or 10-25 wt. %, or at least 5 wt. % or at least 10 wt. %, or at least 15 wt. %, or, optionally, greater than the wax content of the base oil feedstock;
nitrogen content of less than 2500 ppm or less than 2000 ppm or less than 1500 ppm or less than 1000 ppm or less than 500 ppm or less than 200 ppm or less than 100 ppm;
sulfur content of less than 8000 ppm or less than 6000 ppm or less than 4000 ppm or less than 2000 ppm or less than 1000 ppm or less than 500 ppm or less than 200 ppm, or in the range of 100-8000 ppm or 100-6000 ppm or 100-4000 ppm or 100-2000 ppm or 100-1000 ppm or 100-500 ppm or 100-200 ppm; and/or
1050+° F. content in the range of 5-50 wt. % or 5-40 wt. % or 8-40 wt. %, or, optionally, greater than the 1050+° F. content of the base oil feedstock.
Suitable base oil feedstocks may be from any crude oil feedstock, or a fraction thereof, including hydroprocessed intermediate streams or other feeds. Generally, the base oil feedstock contains materials boiling within the base oil range. Feedstocks may include atmospheric and vacuum residuum from a variety of sources, whole crudes, and paraffin-based crudes.
The atmospheric resid (AR) feedstock generally meets one or more of the following property conditions:
API gravity in the range of 20-60 or 20-45 or 25-45, or at least 20, or at least 22, or, optionally, greater than the API of the base oil feedstock;
VI in the range of 50-200 or 70-190 or 90-180, or at least 80, or, optionally, greater than the VI of the base oil feedstock;
viscosity at 100° C. in the range of 3-30 cSt or 3-25 cSt or 3-20 cSt, or at least 3 cSt, or at least 4 cSt;
viscosity at 70° C. in the range of 5-25 cSt or 5-20 cSt or 5-15 cSt, or at least 5 cSt, or at least 6 cSt;
hot C7 asphaltene content in the range of 0.01-0.3 wt. % or 0.01-0.2 wt. % or 0.02-0.15 wt. %, or less than 0.3 wt. %, or less than 0.2 wt. %;
wax content in the range of 5-40 wt. % or 5-30 wt. % or 10-25 wt. %, or at least 5 wt. % or at least 10 wt. %, or at least 15 wt. %, or, optionally, greater than the wax content of the base oil feedstock;
nitrogen content of less than 2500 ppm or less than 2000 ppm or less than 1500 ppm or less than 1000 ppm or less than 500 ppm or less than 200 ppm or less than 100 ppm;
sulfur content of less than 8000 ppm or less than 6000 ppm or less than 4000 ppm or less than 2000 ppm or less than 1000 ppm or less than 500 ppm or less than 200 ppm, or in the range of 100-8000 ppm or 100-6000 ppm or 100-4000 ppm or 100-2000 ppm or 100-1000 ppm or 100-500 ppm or 100-200 ppm; and/or 1050+° F. content in the range of 5-50 wt. % or 5-40 wt. % or 8-40 wt. %, or, optionally, greater than the 1050+° F. content of the base oil feedstock.
In some aspects, AR feedstocks having property characteristics described herein may be advantageously derived from a light tight oil (LTO, e.g., shale oil typically having an API of >45). Suitable feedstocks may be Permian Basin feedstocks and elsewhere, including Eagle Ford, Avalon, Magellan, Buckeye, and the like.
Both the base oil feedstock and the atmospheric resid feedstock may have any of the foregoing properties within any of the noted broad and narrower ranges and combinations of such ranges.
The base oil feedstream generally comprises 10-60 wt. % atmospheric resid feedstock and 40-90 wt. % base oil feedstock, or 10-40 wt. % atmospheric resid feedstock and 60-90 wt. % base oil feedstock, or 10-30 wt. % atmospheric resid feedstock and 70-90 wt. % base oil feedstock, or 30-60 wt. % atmospheric resid feedstock and 40-70 wt. % base oil feedstock, or 40-60 wt. % atmospheric resid feedstock and 40-60 wt. % base oil feedstock.
In certain embodiments, the base oil feedstream does not contain an added whole crude oil feedstock, and/or does not contain a vacuum residue feedstock, and/or does not contain a deasphalted oil feedstock component, and/or contains only atmospheric resid feedstock and base oil feedstock.
While not limited to a straight run process, the process need not include recycle of a liquid feedstock as part of the base oil feedstream or as either or both of the atmospheric resid feedstock and the base oil feedstock. In certain embodiments, recycle of one or more intermediate streams may be desired, however.
The base oil feedstock may comprise vacuum gas oil, or consist essentially of vacuum gas oil, or consist of vacuum gas oil. The vacuum gas oil may be a heavy vacuum gas oil obtained from vacuum gas oil that is cut into a light fraction and a heavy fraction, with the heavy fraction having a cut point temperature range of about 950-1050° F.
The dewaxed product and/or the hydrofinished dewaxed product is typically obtained as a light base oil product and a heavy base oil product. The light base oil product generally has a nominal viscosity in the range of 4-8 cSt or 5-7 cSt at 100° C. and/or with the heavy base oil product generally having a nominal viscosity in the range of 10-14 cSt or 11-13 cSt at 100° C. The dewaxed product may be further separated into at least a light product having a nominal viscosity of about 6 cSt at 100° C., and/or at least a heavy product having a nominal viscosity of about 12 cSt at 100° C., or a combination thereof.
One of the advantages associated with the process is that the yield of the heavy base oil product relative to the light base oil product may be increased by at least about 2 Lvol. %, or at least about 5 Lvol. % (liquid volume %) compared with the same process that does not include the atmospheric resid feedstock in the lubricating oil feedstream. In some embodiments, the yield of the heavy base product may be increased by at least about 10 Lvol. %, or at least about 20 Lvol. %, or at least about 30 Lvol. %, or at least about 40 Lvol. %, compared with the same process that does not include the atmospheric resid feedstock in the base oil feedstream.
In another aspect, the invention concerns a method for modifying a conventional or existing base oil process. In particular, a base oil process that comprises subjecting a base oil feedstream to hydrocracking and dewaxing steps to form a dewaxed product comprising a lighter product and a heavier product may be modified according to the invention by combining an atmospheric resid feedstock with a base oil feedstock to form the base oil feedstream and subjecting the base oil feedstream comprising the atmospheric resid feedstock to the hydrocracking and dewaxing steps of the base oil process to produce a dewaxed product. The dewaxed product may be optionally further contacted with a hydrofinishing catalyst under hydrofinishing conditions to produce a hydrofinished dewaxed product.
The invention further relates to a process for making a base oil, comprising contacting a base oil feedstock having a viscosity index of about 100 or greater with a hydrocracking catalyst under hydrocracking conditions to form a hydrocracked product, wherein the base oil feedstock comprises vacuum gas oil having a front end cut point of about 700° F. or greater and a back end cut point of about 900° F. or less; separating the hydrocracked product into a gaseous fraction and a liquid fraction; contacting the liquid fraction with a dewaxing catalyst under hydroisomerization conditions, to produce a dewaxed product; and optionally, contacting the dewaxed product with a hydrofinishing catalyst under hydrofinishing conditions to produce a hydrofinished dewaxed product; wherein, the dewaxed product and/or the hydrofinished dewaxed product has a viscosity index of 120 or greater after dewaxing. The dewaxed product and/or the hydrofinished dewaxed product may have a viscosity index of 130 or greater after dewaxing, or 135 or greater after dewaxing, or 140 or greater after dewaxing. The hydrocracked product may have a viscosity index of at least about 135, or 140, or 145, or 150. The dewaxed products prepared by the process may be a Group III or Group III+ product.
By comparison to the use of a conventional VGO feedstock, the use of a vacuum gas oil having a front end cut point of about 700° F. or greater and a back end cut point of about 900° F. or less, herein referred to as a medium vacuum gas oil (MVGO) provides an improved waxy product yield at a Group III or Group III+ viscosity of 4 cSt 100° C. of the MVGO that is at least about 3 lvol. % greater than the same process that does not include the MVGO as the base oil feedstock.
The invention further relates to a process that combines the two process aspects, i.e., in which a feedstock is used to derive the narrow cut-point fraction and the same or a different feedstock is used for the atmospheric resid fraction. The combined process for making a base oil from a base oil feedstock, or a fraction thereof, comprises providing an atmospheric resid fraction from a base oil feedstock, or a fraction thereof; separating the base oil feedstock, or a fraction thereof, and/or the base oil atmospheric resid fraction into a narrow vacuum gas oil cut-point fraction having a front end cut point of about 700° F. or greater and a back end cut point of about 900° F. or less to form an MVGO fraction and a residual HHVGO fraction; using the HHVGO fraction as the atmospheric resid feedstock in the first process to prepare a dewaxed product and/or hydrofinished dewaxed product; and/or using the MVGO fraction as the base oil feedstock in a second process to prepare a dewaxed product and/or hydrofinished dewaxed product having a viscosity index of 120 or greater after dewaxing. In certain embodiments, the base oil feedstock may comprise tight oil, particularly a light tight oil, or a fraction thereof. The narrow vacuum gas oil cut-point fraction may also be derived from the atmospheric resid fraction, including an atmospheric resid fraction derived from light tight oil.
Advantageously, the fractionation of the AR feedstock into MVGO and HHVGO fractions provides the ability to produce Group III/III+ base oil product while still allowing the HHVGO fraction to be used with a conventional VGO base oil feedstock to produce a Group II base oil product. In some embodiments, the use of MVGO to produce Group III/III+ base oil product results in greater yields of such products.
An illustration of a method or process according to an embodiment of the invention is shown schematically in
Catalysts suitable for use as the hydrocracking, dewaxing, and hydrofinishing catalysts in the process and method and associated process conditions are described in a number of publications, including, e.g., U.S. Pat. Publication Nos. 3,852,207; 3,929,616; 6,156,695; 6,162,350; 6,274,530; 6,299,760; 6,566,296; 6,620,313; 6,635,599; 6,652,738; 6,758,963; 6,783,663; 6,860,987; 7,179,366; 7,229,548; 7,232,515; 7,288,182; 7,544,285, 7,615,196; 7,803,735; 7,807,599; 7,816,298; 7,838,696; 7,910,761; 7,931,799; 7,964,524; 7,964,525; 7,964,526; 8,058,203; 10,196,575; WO 2017/044210; and others.
Catalysts suitable for hydrocracking, e.g., comprise materials having hydrogenation-dehydrogenation activity, together with an active cracking component support. Such catalysts are well described in many patent and literature references. Exemplary cracking component supports include silica-alumina, silica-oxide zirconia composites, acid-treated clays, crystalline aluminosilicate zeolitic molecular sieves such as zeolite A, faujasite, zeolite X, and zeolite Y, and combinations thereof. Hydrogenation-dehydrogenation components of the catalyst preferably comprise a metal selected from Group VIII metals and compounds thereof and Group VIB metals and compounds thereof. Preferred Group VIII components include cobalt and nickel, particularly the oxides and sulfides thereof. Preferred Group VIB components are the oxides and sulfides of molybdenum and tungsten. Examples of a hydrocracking catalyst which would be suitable for use in the hydrocracking process step are the combinations of nickel-tungsten-silica-alumina, nickel-molybdenum-silica-alumina and cobalt-molybdenum-silica-alumina. Such catalysts may vary in their activities for hydrogenation and for cracking and in their ability to sustain high activity during long periods of use depending on their compositions and preparation.
Typical hydrocracking reaction conditions include, for example, a temperature of from 450° F. to 900° F. (232° C. to 482° C.), e.g., from 650° F. to 850° F. (343° C. to 454° C.); a pressure of from 500 psig to 5000 psig (3.5 MPa to 34.5 MPa gauge), e.g., from 1500 psig to 3500 psig (10.4 MPa to 24.2 MPa gauge); a liquid reactant feed rate, in terms of liquid hourly space velocity (LHSV) of from 0.1 hr−1 to 15 hr−1 (v/v), e.g., from 0.25 hr−1 to 2.5 hr−1; a hydrogen feed rate, in terms of H2/hydrocarbon ratio, of from 500 SCF/bbl to 5000 SCF/bbl (89 to 890 m3H2/m3 feedstock) of liquid base oil (lubricating) feedstock, and/or a hydrogen partial pressure of greater than 200 psig, such as from 500 to 3000 psig; and hydrogen re-circulation rates of greater than 500 SCF/B, such as between 1000 and 7000 SCF/B.
Hydrodewaxing is used primarily for reducing the pour point and/or for reducing the cloud point of the base oil by removing wax from the base oil. Typically, dewaxing uses a catalytic process for processing the wax, with the dewaxer feed is generally upgraded prior to dewaxing to increase the viscosity index, to decrease the aromatic and heteroatom content, and to reduce the amount of low boiling components in the dewaxer feed. Some dewaxing catalysts accomplish the wax conversion reactions by cracking the waxy molecules to lower molecular weight molecules. Other dewaxing processes may convert the wax contained in the hydrocarbon feed to the process by wax isomerization, to produce isomerized molecules that have a lower pour point than the non-isomerized molecular counterparts. As used herein, isomerization encompasses a hydroisomerization process, for using hydrogen in the isomerization of the wax molecules under catalytic hydroisomerization conditions.
Dewaxing generally includes processing the dewaxer feedstock by hydroisomerization to convert at least the n-paraffins and to form an isomerized product comprising isoparaffins. Suitable isomerization catalysts for use in the dewaxing step can include, but are not limited to, Pt and/or Pd on a support. Suitable supports include, but are not limited to, zeolites CIT-1, IM-5, SSZ-20, SSZ-23, SSZ-24, SSZ-25, SSZ-26, SSZ-31, SSZ-32, SSZ-32, SSZ-33, SSZ-35, SSZ-36, SSZ-37, SSZ-41, SSZ-42, SSZ-43, SSZ-44, SSZ-46, SSZ-47, SSZ-48, SSZ-51, SSZ-56, SSZ-57, SSZ-58, SSZ-59, SSZ-60, SSZ-61, SSZ-63, SSZ-64, SSZ-65, SSZ-67, SSZ-68, SSZ-69, SSZ-70, SSZ-71, SSZ-74, SSZ-75, SSZ-76, SSZ-78, SSZ-81, SSZ-82, SSZ-83, SSZ-86, SUZ-4, TNU-9, ZSM-S, ZSM-12, ZSM-22, ZSM-23, ZSM-35, ZSM-48, EMT-type zeolites, FAU-type zeolites, FER-type zeolites, MEL-type zeolites, MFI-type zeolites, MTT-type zeolites, MTW-type zeolites, MWW-type zeolites, MRE-type zeolites, TON-type zeolites, other molecular sieves materials based upon crystalline aluminophosphates such as SM-3, SM-7, SAPO-II, SAPO-31, SAPO-41, MAPO-II and MAPO-31. Isomerization may involve also a Pt and/or Pd catalyst supported on an acidic support material such as beta or zeolite Y molecular sieves, silica, alumina, silica-alumina, and combinations thereof. Suitable isomerization catalysts are well described in the patent literature, see, e.g., U.S. Pat. Nos. 4,859,312; 5,158,665; and 5,300,210.
Hydrodewaxing conditions generally depend on the feed used, the catalyst used, whether or not the catalyst is sulfided, the desired yield, and the desired properties of the base oil. Typical conditions include a temperature of from 500° F. to 775° F. (260° C. to 413° C.); a pressure of from 15 psig to 3000 psig (0.10 MPa to 20.68 MPa gauge); a LHSV of from 0.25 hr−1 to 20 hr−1; and a hydrogen to feed ratio of from 2000 SCF/bbl to 30,000 SCF/bbl (356 to 5340 m3 H2/m3 feed). Generally, hydrogen will be separated from the product and recycled to the isomerization zone. Suitable dewaxing conditions and processes are described in, e.g., U.S. Pat. Nos. 5,135,638; 5,282,958; and 7,282,134.
Waxy products W220 and W600 may be dewaxed to form 220N and 600N products that may be suitable (or better suited) for use as a lubricating base oil or in a lubricant formulation. For example, the dewaxed product may be mixed or admixed with existing lubricating base oils in order to create new base oils or to modify the properties of existing base oils, e.g., to meet particular target conditions, such as viscometric or Noack target conditions, for particular base oil grades like 220N and 600N. Isomerization and blending can be used to modulate and maintain pour point and cloud point of the base oil at suitable values. Normal paraffins may also be blended with other base oil components prior to undergoing catalytic isomerization, including blending normal paraffins with the isomerized product. Lubricating base oils that may be produced in the dewaxing step may be treated in a separation step to remove light product. The lubricating base oil may be further treated by distillation, using atmospheric distillation and optionally vacuum distillation to produce a lubricating base oil.
Typical hydrotreating conditions vary over a wide range. In general, the overall LHSV is about 0.25 hr−1 to 10 hr−1 (v/v), or alternatively about 0.5 hr−1 to 1.5 hr−1. The total pressure is from 200 psig to 3000 psig, or alternatively ranging from about 500 psia to about 2500 psia. Hydrogen feed rate, in terms of Hz/hydrocarbon ratio, are typically from 500 SCF/Bbl to 5000 SCF/bbl (89 to 890 m3 H2/m3 feedstock), and are often between 1000 and 3500 SCF/Bbl. Reaction temperatures in the reactor will typically be in the range from about 300° F. to about 750° F. (about 150° C. to about 400° C.), or alternatively in the range from 450° F. to 725° F. (230° C. to 385° C.).
In practice, layered catalyst systems may be used comprising hydrotreating (HDT, HDM, DEMET, etc.), hydrocracking (HCR), hydrodewaxing (HDW), and hydrofinishing (HFN) catalysts to produce intermediate and/or finished base oils using single or multireactor systems. A typical configuration includes two reactors with the first reactor comprising layered catalysts providing DEMET, HDT pretreatment, HCR, and/or HDW activity. Differing catalysts performing similar functions, e.g., different levels of hydrocracking activity, may be used as well, e.g., in different layers within a single reactor or in separate reactors.
Samples of vacuum gas oil (VGO) and atmospheric resid (AR) were obtained from commercially available sources and used in the process schemes illustrated in
Research unit process conditions used included 0.5 LHSV−1, reactor H2 partial pressure of 1750 psia, hydrogen feed gas oil (recycle) ratio of 4500 scfb, and reactor temperatures in range of 700-770+° F., with the downstream reactor R2 temperature being maintained at 20° F. hotter than the upstream R1 reactor. An ascending temperature profile was imposed, 120° F. and 40° F. AT for R1 and R2, respectively. Waxy product target viscosity indexes (VI's) were set at 109 at 6.0 cSt at 100° C. (W220) and 11.8 cSt at 100° C. (W600).
Bench scale process conditions used included 0.5 LHSV−1, reactor pressure of 1850 psig, hydrogen feed gas oil ratio of 4500 scfb, and reactor temperatures in range of 700-770+° F., with the downstream reactor R2 temperature being maintained at 20° F. hotter than the upstream R1 reactor. Waxy product target viscosity indexes (VI's) were set at 109 at 6.1 cSt at 100° C. (220R) and 11.8 cSt at 100° C. (600R).
The catalyst loading in each of reactors R1 and R2 (according to each of
A sample of vacuum gas oil (VGO) feedstock from a commercially available source used to produce base oil products was obtained and analyzed as a comparative base case. The VGO feedstock was used in the following examples according to the process configurations shown in
Samples of atmospheric resids (AR1 to AR5) from commercially available sources were obtained and analyzed. The properties of these AR samples, which were used as feedstock components according to the invention, are shown in Table 2.
Samples of the atmospheric resids AR1 to AR5 of example 2 were blended with the vacuum gas oil (VGO) feedstock of example 1 on a weight ratio basis and the blends analyzed. The properties of these AR/VGO blend samples, which were used as illustrative feedstocks according to the invention, are shown in Table 3.
The blend feedstock samples AR1 to AR5 of the atmospheric resids with vacuum gas oil (VGO) of example 3 were evaluated for Group II base oil production according to the process represented by
Bench scale process conditions used included 0.5 LHSV−1, reactor pressure of 1850 psig, hydrogen feed gas oil ratio of 4500 scfb, and reactor temperatures in range of 700-770+° F., with the downstream reactor R2 temperature being maintained at 20° F. hotter than the upstream R1 reactor. Waxy product target viscosity indexes (VI's) were set at 109 at 6.1 cSt at 100° C. (220R) and 11.8 cSt at 100° C. (600R).
Base oil production results compared with VGO feedstock alone for the AR1/VGO blend are shown in Table 4a, results for blends of AR2 and AR3 with VGO are shown in Table 4b, and results for blends of AR4 and AR5 with VGO are shown in Table 4c, with each set of results determined using the AR/VGO blends of example 3.
As shown in Table 4a, using the AR1/VGO blend as lube oil process feed showed an improvement in heavy base oil product W600 yield of 57.5 vol % vs. 19.3 vol % when the feed does not include the atmospheric resid AR1 component. This improvement in heavy base oil yield is significant even though the AR1/VGO blend did show some loss in hydrocracking (˜15° F.) and HDN activity loss (19° F. or above). The advantage of high W600 yield suggests a more active and robust HDN catalyst system would also be beneficial, particularly for high nitrogen-containing feedstocks.
Table 4b presents the results obtained for atmospheric resid samples AR2 and AR3 that are each blended with vacuum gas oil (VGO). As shown, the AR2/VGO blend (90-326-3242-3266) provided significant improvements in both actual waxy W600 yield and total actual waxy yield if the same W220 VI (109 or close) is targeted, 36.6% vs. 18.6 for waxy 600R yield, and 69.4% vs. 53.5% for total waxy yield. While a higher waxy product nitrogen content was obtained, the high product N content could be reduced, as shown in 90-326-3098-3122, at the expense of waxy W600R yield and total waxy base oil yield (6% yield decrease for W600R and 2% yield decrease for total waxy base oil yield).
From Table 4b, the AR3/VGO blend (88-342-3726-3750) showed significant actual waxy W600R yield improvement compared to VGO feed alone, 31.9% vs. 18.6%. The total actual waxy base oil yield remained the same, while the waxy products from the AR3/VGO blend showed slightly higher nitrogen content.
Table 4c presents the results obtained for atmospheric resid samples AR4 and AR5 that are each blended with vacuum gas oil (VGO). As shown, two separate runs were performed at different hydrocracking severities for each of the VGO comparative feed and the AR4/VGO and AR5/VGO blends.
Results from Table 4c provide a basis for comparison of waxy base oil yields at a viscosity index (VI) of 109 for W220 for AR2/VGO, AR4/VGO, and AR5/VGO blends, as shown in Table 4d. At 109 W220 VI, compared to VGO feed alone, the 50% AR2/VGO blend feed showed a waxy base oil yield improvement in W600 yield of 33.7% compared with a W600 yield of 25.8% for VGO feed alone that does not include the atmospheric resid AR2 component. A total waxy base oils yield of 68.7% for the AR2/VGO blend was obtained compared with a total waxy base oils yield of 66.1% when the feed did not contain the AR2 blend component.
The 20% AR4/VGO blend also showed improvements in both W600 yield of the AR4/VGO blend compared with the VGO feed by itself (28.4% vs. 25.8%), in W220 yield of the AR4/VGO blend compared with the VGO feed by itself (42.9% vs. 40.3%), and the total waxy base oil yield of the AR4/VGO blend compared with the VGO feed by itself (71.3% vs. 66.1%).
Similarly, the 20% AR5/VGO showed improvement in W220 yield of the AR5/VGO blend compared with the VGO feed by itself (44.4% vs. 40.3%) and in total waxy base oil W600 yield of the AR5/VGO blend compared with the VGO feed by itself (68.1% vs. 66.1%).
Samples of atmospheric resid (AR) were evaluated to provide medium grade vacuum gas oils (MVGO) for use in producing group III/III+ base oils. The MVGO samples were derived from the corresponding AR samples as distillation cuts in the following ranges: AR2 cut range of 717-876° F.; AR4 cut range of 725-882° F.; and, AR5 cut range of 716-882° F. Table 5a presents properties of the AR samples AR2, AR4, and AR5 and the corresponding MVGO derived cuts MVGO2, MVGO4, and MVGO5. Properties for the comparative vacuum gas oil (VGO) are also included.
The three atmospheric resid (AR) derived MVGO's were evaluated using the process configuration of
Samples of atmospheric resid feed sample AR3 were evaluated to provide medium grade vacuum gas oils (MVGO) for use in producing group III/III+ base oils. The MVGO samples were derived from the corresponding AR3 samples as distillation cuts in the 725-895° F. range, designated as MVGO3b (broad temperature range cut), and 725-855° F., designated as MVGO3n (narrow temperature range cut).
Table 6 presents the results using the MVGO3b and MVGO3n feeds to produce group III 4 cSt base oils using the process configuration of
As noted in Example 5, samples of atmospheric resid (AR) were used to provide medium grade vacuum gas oils (MVGO) for use in producing group III/III+ base oils. The remaining fraction, absent the MVGO fraction, was designated as an HHVGO fraction. These HHVGO fractions were evaluated for use as feed components blended with vacuum gas oils (VGO) to produce Group II base oils.
Table 7a presents the properties of the HHVGO samples HHVGO2, HHVGO4, and HHVGO5 and blend of 9% HHVGO/VGO and 9% HHVGO/VGO. Properties of the comparative VGO feed are also shown.
Table 7b presents the results using the HHVGO/VGO blend feeds to produce group II base oils using the process configuration of
The foregoing description of one or more embodiments of the invention is primarily for illustrative purposes, it being recognized that variations might be used which would still incorporate the essence of the invention. Reference should be made to the following claims in determining the scope of the invention.
For the purposes of U.S. patent practice, and in other patent offices where permitted, all patents and publications cited in the foregoing description of the invention are incorporated herein by reference to the extent that any information contained therein is consistent with and/or supplements the foregoing disclosure.
This application claims the benefit of priority to PCT Appl. No. PCT/162020/057559, filed on Aug. 12, 2020, and to U.S. Provisional Patent Appl. Ser. No. 62/885,359, filed on Aug. 12, 2019, the disclosures of which are herein incorporated in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2020/057559 | 8/12/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62885359 | Aug 2019 | US |
