Description:FIELD OF THE INVENTION
[0001] The present disclosure generally relate to a field of petroleum refining and chemical engineering. More particularly, the present disclosure relates to a method of production of naphthenic base oils from low value refiney streams namely, hydrotreated vacuum gas oil, fluidised bed cracking (FCCU) derived light cycle oil and clarified oil, light coker gas oil, hydrotreated vacuum gas oil derived diesel streams.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Naphthenic base oils represent a special class of lubricants due to their advantageous properties, including high solvency, low wax content, low pour point, low aromatic content, and exceptional performance across various industrial applications. These oils find widespread use in multiple industries, including rubber and polymer processing, hydraulic and transmission fluids, transformer dielectric fluids, metal cutting oils, white oils as well as in the formulation of inks, paints, coatings, and personal care products. In the paint and coatings industry, naphthenic base oils enhance resin solubility, contributing to smooth film formation and superior finishes. Their high solvency power also facilitates effective removal of oils, greases, and waxes, making them highly suitable for degreasing and cleaning applications. Furthermore, their low pour point and excellent thermal stability, ensures reliable performance under extreme lubrication requirement. In adhesives, the slower evaporation rate of naphthenic base oils improves bonding time and minimizes shrinkage, leading to stronger adhesion. For inks, controlled volatility ensures uniform drying and high-quality print results. In metal cleaning, naphthenic oils efficiently dissolve residues without leaving a greasy film, providing clean surfaces for further processing. Aromatic free naphthenic base white oils make good choice in various industries specifically personal care, textile industry and food industry. These versatile properties make naphthenic base oils indispensable across both industrial and consumer applications.
[0004] Traditionally, naphthenic base oils and solvents with a boiling range of 120-550 °C are primarily produced by refining of naphthenic crude oils, which are defined as a mineral crude oil having a K value for the Watson characterisation factor in between 11 and 12, through combinaton of distillation, extraction and hydroprocessing route. Typical Naphthenic crudes include for instance the African crudes, such as Forcados, Nigerian light, Far East crudes such as champion export, venezulean crudes such as tina jnana pesada and laguna; and Danish crude such as DVC crudes. However, this route has major limitation w.r.t. limited availability of naphthenic crude oils leading to supply-demand gap.
[0005] Naphthenic oils are distinct from paraffinic base oils and refers to a base oil with a viscosity index typically less than 85, and a high proportion of naphthenic (cycloalkane) carbon structures—often more than 30%—as determined by carbon-type analysis methods such as ASTM D2140.
[0006] Naphthenic feedstock typically will contain at least about 30 wt% CN content (carbon bonds are of Naphthenic type) and less than about 70 wt% total CP plus CA content (carbon bonds are of paraffinic and aromatics type) as measured according to ASTM D2140.
[0007] Considering limited availability of naphthenic crude oils, it is necessary to develop a versatile process capable of producing naphthenic oils with desired properties based on widely traded and used paraffinic crudes for production of transportation fuels.
[0008] Paraffinic feedstock typically contains at least about 60 wt% CP content and less than 40 wt% total CN and CA content as measured according to ATSM D 2140.
[0009] The term “Paraffinic” when used with respect to feedstock, process stream or product refers to a liquid material having Viscosity Gravity Constant (VGC) near 0.8 (e.g less than 0.85) as determined by ASTM D2501.
[0010] The terms “Viscosity-Gravity Constant” (VGC) refer to an index for the approximate characterization of the viscous fractions of petroleum.VGC is defined as the general relation between specific gravity and Saybolt Universal viscosity, and may be determined according to ASTM D2501.VGC is relatively insensitive to molecular weight.
[0011] This process should be adaptable to various feedstocks, including naphthenic crude oils, paraffinic crude oils, blends of naphthenic and paraffinic crude oils, and combinations of naphthenic crude oils with other feedstocks, while ensuring optimal product yields and desired performance characteristics.
[0012] In this context, the patent US 8,691,076 B2 describes method of manufacturing naphthenic base oil, which includes hydrotreating and isomerization an inexpensive hydrocarbon feedstock LCO or slurry oil which is bottom product of the FCC having a high aromatic content and large amounts of impurities, under extreme conditions, thereby producing naphthenic base oil with high yield. However, the feed quality disclosed in this patent application contains PAH of greater than 55 wt% and sulfur and nitrogen are more than 7000 and 2000 ppm respectively which are very difficult to treat and severe process conditions are required. In this methodology, design of reactor system to control exothermicity is highly challenging due to high level of sulfur, nitrogen and polyaromatics (PAH) species.
[0013] U.S. Patent US 10,479,949 B2 describes a process for producing naphthenic base oil. This process is not independent of crude oil type, additionally it requires deasphalted stream for producing naphthenic base oils of pour point upto -9 Deg C.
[0014] Patent WO 2016/044637 A1 describes a process for producing naphthenic base oil from low quality naphthenic crude using hydroprocessing approach. The process described limits use of naphthenic crude oils.
[0015] US patent application 2020/0199464 A1 depicts the naphthenic oil production process from FCC bottom product as feed stock. The process involves hydrotreating and aromatic saturation of the slurry oil under controlled conditions without catalytic dewaxing, however this method uses solvent deasphalting to remove paraffins to meet the pour point or cold flow propertries. After employing solvent extraction of paraffins also, the resultant products pour point is not provided in the patent application. Overall the provided process is complex in nature with solvent deasphalting and combined with hydroprocessing. Its commercial exploitation seems to be difficult. In addition to that, to achieve low pour point additional processing steps like hydroisomerization may be required.
[0016] European patent EP3397723B1 discloses that it can produce lubricating base stock from disadvantges feeds such as lube extracts, heavy cycle oils from FCC, vacuum gas oils. This method includes hydrotreating, solvent extraction, followed by either additional solvent extraction or hydroprocessing, and catalytic dewaxing. The process typically involves either: (1) two hydroprocessing steps, one solvent extraction, and one catalytic isomerization step; or (2) one hydroprocessing step and two solvent extraction steps. In the first approach, the number of unit operations is higher, while in the second, the repeated solvent extraction can lead to a reduction in the desired yield.
[0017] In summary the reported prior arts demand either
a. Naphthenic crude oils
b. High severity operations
c. More unit operations including solvent extraction
d. Deasphalted feed stock
[0018] In view of the above, there is a need for a crude independent process which produces different grades of naphthenic base oils and solvents from low value streams such as FCC streams, (hydrotreated vacuum gas oil), light coker gas oil originating from Delayed Coker Unit (DCU), hydrotreated vacuum gas oil derived diesel streams with practical yet effective process scheme.

OBJECTS OF THE INVENTION
[0019] An object of the present disclosure is to provide a method of production of naphthenic base oils using feedstock derived with combination of Fludized bed Catalytic Cracking (FCC) streams originating from hydrotreated vacuum gas oil, light coker gas oil, hydrotreated vacuum gas oil and hydrotreated vacuum gas oil derived diesel streams.
[0020] Another object of the present disclosure is to provide a method employing hydrotreated Vacuum Gas Oil (VGO) for FCC, resulting in a feedstock with total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content of less than 1000 ppm.
[0021] Still another object of the present disclosure is to provide an unique blend feed composition that requires mild processing conditions.
[0022] Yet another object of the present disclosure is to provide the naphthenic base oils with optimized cold flow properties, within a specific boiling range suitable for their intended applications such as ink oils, naphthenic solvents, white oils and transformer oils.

SUMMARY OF THE INVENTION
[0023] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
[0024] An aspect of the present disclosure is to provide a method of production of naphthenic base oils from a feedstock originating from combination of aromatic rich diesel and hydrotreated vacuum gas oil along with its FCC product streams, comprising: a) hydroprocessing of a vacuum gas oil (VGO), heavy coker gas oil (HCGO) and light coker gas oil (LCGO) in presence of a catalyst to obtain a hydrotreated VGO and aromatic rich diesel (ARD); b) subjecting a portion of hydrotreated VGO to a fluidized bed catalytic cracking to obtain a distilled fraction F1 and F2 streams; c) subjecting F1 stream, F2 stream, ARD and remaining hydrotreated VGO alone or in combination to fracationation thereof to create suitable feedstock for further refinement, wherein the feedstock is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatic, nitrogen content of less than 100 ppm, and sulfur content of less than 1000 ppm; d) hydrotreating the feedstock of step c) in the presence of hydrogen and a hydrotreating catalyst under hydrotreating conditions to obtain a first liquid product; e) hydro-isomerization the first liquid product of step d) in presence of hydrogen and a hydro-isomerization catalyst under hydro-isomerization conditions to obtain a second liquid product; f) hydro-saturation the second liquid product of step e) in presence of hydrogen and a hydro-saturation catalyst under hydro-saturation conditions to obtain a naphthenic base oils mixture; and g) fractionating the naphthenic base oils mixture into one or more fractions of naphthenic base oils, wherein the feedstock obtained in step c) is hydroprocessed through at least one of steps from d) to) f) or combination thereof to obtain the naphthenic base oils mixture.
[0025] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and together with the description, serve to explain the principles of the present disclosure.
[0027] FIG. 1 is a schematic diagram illustrating the production method for naphthenic base oils using feedstock obtained from a fractionator. The fractionator feed comprises some portion of hydrotreated vacuum gas oil (VGO) and its downstream products F1 and F2 from a fluid catalytic cracking (FCC) unit and aromatic rich diesel (ARD). Finally the feedstock is refined by hydrotreating, hydro-isomerization and hydro-saturation steps.
[0028] FIG. 2 is a schematic diagram illustrating the production method for naphthenic base oils using feedstock derived from fractions of hydrotreated vacuum gas oil (VGO), portions of fluid catalytic cracking (FCC) products F1 and F2, and a portion of aromatic rich diesel (ARD). The feedstock is further subjected to sequential hydrotreating, hydro-dewaxing, and hydro-saturation processes.
[0029] FIG. 3 is a schematic diagram illustrating the production method for naphthenic base oils using feedstock obtained from a fractionator. The fractionator feed comprises some portion of hydrotreated vacuum gas oil (VGO) and its downstream products F1 and F2 from a fluid catalytic cracking (FCC) unit. Finally the feedstock is refined by hydrotreating, hydro-isomerization and hydro-saturation steps.
[0030] FIG. 4 is a schematic diagram illustrating the production method for naphthenic base oils using feedstock derived from fractions of hydrotreated vacuum gas oil (VGO), portions of fluid catalytic cracking (FCC) products F1 and F2. The feedstock is further subjected to sequential hydrotreating, hydro-dewaxing, and hydro-saturation processes.

DETAILED DESCRIPTION OF THE INVENTION
[0031] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0032] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0033] Unless the context requires otherwise, throughout the specification which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense that is as “including, but not limited to.”
[0034] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
[0035] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
[0036] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range.
[0037] Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[0038] The headings and abstract of the invention provided herein are for convenience only and do not interpret the scope or meaning of the embodiments.
[0039] Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
[0040] The following description provides different examples and embodiments of the inventive subject matter. Although each embodiment represents a single combination of inventive elements, the inventive subject matter is considered to include all possible combinations of the disclosed elements. Thus, if one embodiment comprises elements A, B, and C, and a second embodiment comprises elements B and D, then the inventive subject matter is also considered to include other remaining combinations of A, B, C, or D, even if not explicitly disclosed.
[0041] All percentages, ratios, and proportions used herein are based on a weight basis unless otherwise specified.
[0042] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[0043] The present disclosure is on premise of producing a desired feedstocks through a controlled, multi-step process. Initially, Vacuum Gas Oil (VGO), Light Coker Gas Oil (LCGO), Heavy Coker Gas Oil (HCGO) undergoes hydrotreating to eliminate impurities, resulting in a mildly hydrocracked product.
[0044] The portion of hydrotreated VGO is then subjected to fluidized bed catalytic cracking, producing F1 and F2, which are separated via distillation into distinct fractions.
[0045] These fractions along with either some portion of remaining hydrotreated VGO, and or aroamatic rich diesel (ARD) fractions origninating from VGO hydrotreatment can be blended to create a variety of feedstocks with or without fractionator. The feedstock is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content of less than 1000 ppm. Subsequently, the feedstocks are further refined using a combination of hydrotreating, hydrogenation, and hydroisomerization or hydro-isomerization processes. This series of treatments results in the production of naphthenic base oils with optimized cold flow properties, within a specific boiling range suitable for their intended applications.
[0046] An embodiment An embodiment of the present disclosure provides a method of production of naphthenic base oils from a feedstock originating from combination of aromatic rich diesel and hydrotreated vacuum gas oil along with its FCC product streams, comprising: a) hydroprocessing of a vacuum gas oil (VGO), heavy coker gas oil (HCGO) and light coker gas oil (LCGO) in presence of a catalyst to obtain a hydrotreated VGO and aromatic rich diesel (ARD); b) subjecting a portion of hydrotreated VGO to a fluidized bed catalytic cracking to obtain a distilled fraction F1 and F2 stream; c) subjecting F1 stream, F2 stream, ARD and hydrotreated VGO alone or in combination to fracationation thereof to create suitable feedstock for further refinement, wherein the feedstock is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatic, nitrogen content of less than 100 ppm, and sulfur content of less than 1000 ppm; d) hydrotreating the feedstock of step c) in the presence of hydrogen and a hydrotreating catalyst under hydrotreating conditions to obtain a first liquid product; e) hydro-isomerization the first liquid product of step d) in presence of hydrogen and a hydro-isomerization catalyst under hydro-isomerization conditions to obtain a second liquid product; f) hydro-saturation the second liquid product of step e) in presence of hydrogen and a hydro-saturation catalyst under hydro-saturation conditions to obtain a naphthenic base oils mixture; and g) fractionating the naphthenic base oils mixture into one or more fractions of naphthenic base oils, wherein the feedstock obtained in step c) is hydroprocessed through at least one of steps from d) to) f) or combination thereof to obtain the naphthenic base oils mixture.
[0047] In some embodiment, the catalyst in step a) is selected from a group comprising of CoMo, NiMo, NiW and combination thereof. Preferably, the catalyst in step a) is NiMo.
[0048] In some embodiment, the hydroprocessing in step a) is carried out at a temperature ranging from 300 to 450 °C and 50 to 150 bar hydrogen pressure. Preferably, the temperature ranging from 350 to 400 °C and 80 to 120 bar hydrogen pressure. More preferably, the temperature ranging from 370 °C and 110 bar hydrogen pressure.
[0049] In some embodiment, the fluidized bed catalytic cracking is carried out in presence of a Y-zeolite catalyst ranging from 20-45 wt%. Preferably, the catalyst is 40 wt% Y-zeolite.
[0050] In some embodiment, the fluidized bed catalytic cracking in step b) is carried out at a temperature ranging from 450 to 600 °C. Preferably, the temperature ranging from 500 to 550 °C. More preferably, the temperature is 520 °C.
[0051] In some embodiment, the distilled fraction F1 stream having a boiling range of 150-320°C and distilled fraction F2 stream having a boiling range of 300-450°C.
[0052] In some embodiment, the remaining hydrotreated VGO and/or aromatic rich diesel (ARD) is combined with portions of fractions F1 and F2 to form a blend stream B1 and the blend stream B1 is either treated directly as feedstock or subjected to fractionation to generate blend 2 (B2) that is suitable for further treatment of preparing napthenic base oil. The obtained B1 or B2 is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content of less than 1000 ppm.
[0053] As the feedstock of the method according to the present disclosure, the hydrotreated VGO and / or ARD, and / or streams originating from hydrotreated VGO, F1 and F2 are used alone, or mixture of predetermined ratio, with or without fractionator.
[0054] In some embodiments, the remaining hydrotreated VGO, fractions F1, F2, and ARD are mixed in the following ratio ranges to form blend B1: Remaining hydrotreated VGO: (0-3), Fraction F1: (2-6), Fraction F2: (3-6), ARD: (1-3). Preferably, the mixing ratio is (1-2): (4-6): (2-5): (1-2) respectively. In some embodiments, fraction F1 comprises 20-50% of the total blend, with a preferred range of 30-40%.
[0055] In another embodiment, the hydrotreated vacuum gas oil (VGO), aromatic rich diesel (ARD) product, and streams derived from hydrotreated VGO, F1, and F2 are combined in a ratio of 1–3 parts hydrotreated VGO, 1–3 parts ARD, 3–6 parts F1-derived stream, and 4–6 parts F2-derived stream. This mixture is subsequently fed into a fractionator to isolate a feed fraction with a boiling point range of 190–500°C.
[0056] In some embodiment, the hydrotreated VGO, ARD, F1 stream and F2 stream in step c) are mixed in an amount ranging from 20-30 wt%, 25-50 wt%, 30-50 wt% and 20-40wt% respectively.
[0057] In some embodiment, the hydrotreated VGO, F1 stream and F2 stream in step c) are mixed in an amount ranging from 20-40 wt%, 30-50 wt%, 30-50 wt% respectively.
[0058] In some embodiment, the hydrotreating conditions in step d) includes a temperature ranging from 300 to 400 °C, pressure ranging from 80 to 150 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.8 to 1.4 hr-1 and gas to oil ratio ranging from 800 to 1200 nm3/m3. Preferably, the temperature ranging from 320 to 380 °C, pressure ranging from 80 to 140 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.9 to 1.3 hr-1 and gas to oil ratio ranging from 800 to 1000 nm3/m3. In some embodiment, the temperature is 360 °C, pressure is 120 bar hydrogen pressure, a feed weight hour space velocity is 1.2 hr-1 and gas to oil ratio is 1000 nm3/m3. In some another embodiment, the temperature is 340 °C, pressure is 130 bar hydrogen pressurre, a feed weight hour space velocity is 0.9 hr-1 and gas to oil ratio is 800 nm3/m3.
[0059] In some embodiment, the hydrotreating catalyst in step d) is selected from a group comprising of alumina supported catalyst comprise of nickel, molybdenum, cobalt, tungsten and mixture thereof. Preferably, the hydrotreating catalyst is NiMo in alumina support.
[0060] In some embodiment, the hydro-isomerization condition in step e) includes a temperature ranging from 280 to 380 °C, pressure ranging from 80 to 180 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.8 to 1.6 hr-1 and gas to oil ratio ranging from 600 to 1000 nm3/m3. Preferably, the temperature ranging from 300 to 360 °C, pressure ranging from 80 to 160 bar hydrogen pressure, a feed weight hour space velocity ranging from 1.0 to 1.5 hr-1 and gas to oil ratio ranging from 600 to 900 nm3/m3. In some another embodiment, the temperature is 350 °C, pressure is 130 bar hydrogen pressure, a feed weight hour space velocity is 1.0 hr-1 and gas to oil ratio is 600 nm3/m3.
[0061] In some embodiment, the hydro-isomerization catalyst in step e) is selected from a group comprising of platinum loaded on ZSM22, ZSM23, ZSM48 and mixture thereof. Preferably, the hydro-isomerization catalyst platinum loaded on ZSM22.
[0062] In some embodiment, the hydro-saturation condition in step f) includes a temperature ranging from 150 to 280 °C, pressure ranging from 110 to 200 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.8 to 1.6 hr-1 and gas to oil ratio ranging from 500 to 1000 nm3/m3. Preferably, the hydro-saturation condition in step f) includes a temperature ranging from 200 to 260 °C, pressure ranging from 120 to 180 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.8 to 1.5 hr-1 and gas to oil ratio ranging from 800 to 1000 nm3/m3. In some embodiment, the temperature is 240 °C, pressure is 180 bar hydrogen pressure, a feed weight hour space velocity is 1.0 hr-1 and gas to oil ratio is 800 nm3/m3.
[0063] In some embodiment, the hydro-saturation catalyst in step f) is supported catalyst comprises of silica-alumina mixed oxide with nickel or palladium or platinum or combination thereof. In the silica-alumina mixed oxide, the silica remain in the range of 20-80 wt% range and gama-alumina are used as catalyst support. Preferably, the silica-alumina mixed oxide of having silica 20-50 wt%. Nickel remains in 3-15 wt% , Pd remains in 0.4-5 wt% and Pt remains in 0.2 to 3 wt%. In some embodiment, the hydro-saturation catalyst is Pd-Pt (0.5 wt%-0.5 wt%)/ silica-alumina mixed oxide (silica-40 wt%).
[0064] In some embodiment, the method optionally comprises a step of fractionating the feedstock of step c) to obtain a portion of feedstock that is further hydroprocessed through steps d) to f) to obtain the naphthenic base oils mixture.
[0065] In some embodiment, the steps d) to f) are carried out with minimal exothermic reactions.
[0066] In some embodiment, the naphthenic base oils have a pour point ranging from -40 to -60°C.
[0067] In some embodiment, the naphthenic base oil composition comprising 100 wppm or less sulfur, 10-30 wt% of paraffinic components, 35 wt% or more of naphthenic components, kinematic viscosity at 40 °C of 2 to 12 cSt, pour point of less than -40°C and with distillation boiling range of 200-410 °C.
[0068] In some embodiment, the boiling point of the first fraction, second fraction, third fraction and fourth fraction of the naphthenic base oils ranging from 200-240 °C, 240-280 °C, 280-320 °C and 320-410 °C respectively.
[0069] In some another embodiement, the feedstock is characterized by polyaromatic hydrocarbon ranging from 20 to 50 wt%.
[0070] In some another embodiement, the feedstock is characterized by total aromatic content ranging from 40 to 60 wt%.
[0071] In some embodiment, the feedstock is characterized by sulfur content less than 900 ppm or less than 800 ppm or less than 700 ppm or less than 600 ppm or less than 500 ppm or less than 400 ppm or less than 300 ppm or less than 200 ppm or less than 100 ppm or less than 50 ppm. In some another embodiment, the feedstock is characterized by sulfur content ranging from 100 to 1000 ppm.
[0072] In some embodiment, the feedstock is characterized by nitrogen content less than 90 ppm or less than 80 ppm or less than 70 ppm or less than 60 ppm. In some another embodiment, the feedstock is characterized by nitrogen content ranging from 50 to 100 ppm.
[0073] In some embodiment, the naphthenic base oils have total aromatics content less than 10 wt %. Preferably, less than 9 wt % or less than 8 wt % or less than 7 wt % or less than 6 wt % or less than 5 wt % or less than 4 wt % or less than 3 wt % or less than 2 wt % or less than 1 wt % or less than 100 ppm.
[0074] In some embodiment, the naphthenic base oils have polyaromatic content less than 5 wt %. Preferably, less than 3 wt % or less than 2 wt % or less than 1 wt % or less than 100 ppm.
[0075] In some embodiment, the combined liquid naphthenic product have density ranging from 0.8 to 0.9 gm/cm3.
[0076] In another embodiment, the combined liquid naphthenic product have density ranging from 0.85 to 0.93 gm/cm3.
[0077] In some embodiment, the combined liquid naphthenic product have kinematic viscosity at 40 °C ranging from 2.0 to 12.0 mm2/s.
[0078] In some embodiment, the combined liquid naphthenic product have pour point ranging from -40 to -70 °C.
[0079] In some embodiment, the combined liquid naphthenic product total aromatics content ranging less than 10 wt%. Preferably, less than 5 wt% or less than 2 wt% or less than 1 wt% or less than 100 ppm.
[0080] In some embodiment, the combined liquid naphthenic product Hydrogen/Carbon ratio is ranging from 14 to 18. Preferably more than 12 wt% or more than 14% or more than 16%.
[0081] The present disclosure outlines a novel series of feedstocks produced through a multi-step process. Initially, vacuum gas oil (VGO) and / or LCGO and / or HCGO, with LCGO and HCGO content not more than 30 wt% of the total feed undergoes hydroprocessing in the presence of a CoMo/NiMo catalyst at approximately 370°C and 110 bar hydrogen pressure and produces hydrotreated VGO and aromatics rich diesel (ARD) along with other products. This is followed by fluidized bed catalytic cracking of the hydrotreated VGO at temperatures ranging from 520-550°C, with the application of an appropriate cut point to produce F1 and F2. The remaining portion of the hydrotreated VGO, ARD, and FCCU fractions F1 and F2 are mixed together in particular ratio to make blend B1. c) the blended stream B1 is either can be treated directly as feedstock or subjected to fractionation to generate blend 2 (B2) that is suitable for further treatment of preparing napthenic base oil. The obtained B1 or B2 is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm, and sulfur content of less than 1000 ppm.
[0082] These feedstocks are subsequently subjected to hydrotreating, hydrogenation, and hydroisomerization, or combinations of these processes, with minimal exothermic reactions, producing naphthenic oil-grade base oils. Minimum exothermicity occurs in first stage hydrogenation. Due to low sulfur less than 1000 ppm instead of prior art 10000 to 20000 ppm. The final products exhibit favorable cold flow properties of -50°C and fall within the desired viscosity range, making them suitable for various industrial applications.
[0083] According to the present disclosure, as illustrated in FIG. 1, VGO and / or LCGO and / or HCGO, is hydrotreated at a temperature of 370°C under 110 bar hydrogen pressure in the presence of a CoMo/NiMo catalyst, operating at a conversion rate of less than 50%. The portion of treated VGO is then subjected to fluidized bed catalytic cracking at a temperature of 520°C, resulting in the formation of F1 and F2 streams. Some portions of the remaining hydrotreated VGO, aromatic rich diesel and streams F1 and F2 which are originating from hydrotreated VGO in FCCU are subjected to fractionator to obtain the requisite feed fraction of boiling range 190-500 °C.
[0084] The resulted feed stream then subjected as a feedstock to first stage hydrotreating in the presence of hydrogen using supported catalyst comprise nickel and molybdenum as active metal component at process conditions of temperature of 370 °C, pressure of 110 bar, a feed weight hour space velocity of 0.9 hr-1 and gas to oil ratio of 1000 nm3/m3. The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor with hydro-isomerization catalyst with platinum loaded on ZSM 22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization are temperature of 330 °C, pressure of 100 bar, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 1000 nm3/m3. The liquid product mixture from second stage hydrogenation is subjected to third stage hydrogenation or hydro-saturation. Hydro-saturation is carried out on supported catalyst with nickel as active metal component and in the presence of hydrogen to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 150 bar, a feed space velocity of 0.6 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product from stage 3 reactor is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications.
[0085] According to the present disclosure, and as shown in FIG. 2, a mixture of VGO, LCGO, and HCGO is subjected to hydrotreatment at 370°C under a hydrogen pressure of 100 bar, using a CoMo or NiMo catalyst. The process operates at a conversion rate of less than 50%, producing hydrotreated VGO, aromatic-rich diesel (ARD), and other products. The hydrotreated VGO is then processed through fluidized bed catalytic cracking at 520°C, yielding distilled fractions F1 and F2. Portions of F1, F2, hydrotreated VGO, and ARD are subsequently blended in specific ratios to produce a feed fraction with the desired properties for further processing.
[0086] Blend feed is subjected to hydrotreatment in the presence of hydrogen using supported catalyst comprise nickel and molybdenum as active metal component at process conditions of temperature of 340 °C, pressure of 80 bar, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 800 nm3/m3. The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor for hydrogenation or hydro-saturation. Hydro-saturation carried out on supported catalyst with nickel as active metal component and in the presence of hydrogen to improve cold flow properties as well minimizing aromatics at the process conditions of temperature of 330 °C, pressure of 110 bar, a feed space velocity of 1.0 hr-1 and gas to oil ratio of 800 nm3/m3. The final product is then fractionated to yield NS1, NS2, NS3 and NS4, each with an appropriate boiling range, cold flow properties, and viscosity, making them suitable for various applications.
[0087] According to the present disclosure, and as shown in FIG. 3, VGO is treated as discussed above to obtain a treated VGO. The treated VGO is then subjected to fluidized bed catalytic cracking at 520°C, resulting in the formation of F1 (boiling range 150-320 degC) and F2 ( boiling range 300-450 oC) distilled fractions. Fractions F1 and F2 along with hydrotreated VGO boiling in the range of 350-520 oC are subsequently blended in suitable proportions. The streams F1, F2 and hydrotreated VGO mixed in the range of 30-50 wt%, 30-50wt% and 30-45 wt% respectively and the mixed stream is subjected to fractionator V1 to to obtain suitable feedstock for downstream processing. The feedstock is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatic, nitrogen content of less than 100 ppm, and sulfur content of less than 1000 ppm. The resulted feedstock is first undergone hydroisomerization with platinum loaded on ZSM 22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization are temperature of 330 °C, pressure of 100 bar, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 1000 nm3/m3. Further, the liquid product mixture is subjected to hydrogenation or hydro-saturation. Hydro-saturation is carried out on supported catalyst with nickel as active metal component and in the presence of hydrogen to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 150 bar, a feed space velocity of 0.6 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications.
[0088] According to the present disclosure, and as shown in FIG. 4, VGO is treated as discussed above to obtain a treated VGO. The treated VGO is then subjected to fluidized bed catalytic cracking at 520°C, resulting in the formation of F1 (boiling range 150-320 degC) and F2 (boiling range 300-450 oC) distilled fractions. Fractions F1 and F2 along with hydrotreated VGO boiling in the range of 350-520 oC are subsequently blended in suitable proportions. The blended feedstock suitable for downstream processing is prepared by mixing F1, F2 and hydrotreated VGO in the range of 30-50 wt%, 30-50wt% and 20-30 wt% respectively. The resulted feedstock is first hydrotreated with NiMo in alumina support at a temperature of 360 °C, pressure of 120 bar hydrogen pressure, a feed weight hour space velocity is 1.2 hr-1 and gas to oil ratio is 1000 nm3/m3. The resulted product is then subjected to hydroisomerization with platinum loaded on ZSM 22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization are temperature of 330 °C, pressure of 100 bar, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 1000 nm3/m3. Further, the liquid product mixture is subjected to hydrogenation or hydro-saturation. Hydro-saturation is carried out on supported catalyst with nickel as active metal component and in the presence of hydrogen to reduce aromatic content as well as to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 150 bar, a feed space velocity of 0.6 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications.
[0089] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person skilled in the art.

EXAMPLES
[0090] The present disclosure is further explained in the form of the following examples. However, it is to be understood that the examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope and spirit of the present invention.
Example 1:
[0091] The process begins with the hydrotreatment of mixture of VGO, LCGO, and HCGO at 370°C under 110 bar hydrogen pressure in the presence of a NiMo catalyst. The process operates at a conversion rate of less than 50%, producing hydrotreated VGO, aromatic-rich diesel (ARD), and other by-products. The treated VGO, is subjected to fluidized bed catalytic cracking at a temperature of 520°C. This process produces two primary distilled fractions F1 (boiling range 150-320 oC) and F2 (boiling range 300-450 oC). These fractions along with hydrotreated VGO boiling in the range of 350-520 oC and aromatics rich diesel (ARD) boiling in the range of 220-340 oC are subsequently mixed. The mixing ratio of F1, F2, ARD and hydrotreated VGO remain in the range of 20-50 wt%, 20-50 wt%, 20-30 wt% and 20-30 wt% respectively. The mixed stream is subjected to fractionator V1 to to obtain suitable feedstock for downstream processing.
[0092] Characterization data of the feed, as detailed in Table 1, indicate the presence of total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen level of less than 100 ppm and sulfur level within the range of less than 1000 ppm. This composition supports efficient hydroprocessing with minimal exothermic heat generation.
[0093] Feed stream is subjected to first stage hydrotreatment in the presence of hydrogen using gama-alumina supported (10-20 wt%) Ni/Mo (1:1) as active metal component at process conditions of temperature of 340 °C, pressure of 80 bar, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 800 nm3/m3.
[0094] The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor for further hydroprocessing steps namely hydroisomerization and hydro-saturation. Hydroisomerization is carried out over ZSM-22 based noble metal catalyst at the process conditions of temperature of 330 °C, pressure of 160 bar ,a feed space velocity of 1.0 hr-1 and gas to oil ratio of 800 nm3/m3 and Hydro-saturation carried out on silica-alumina mixed oxide with noble metal as active metal component at the process conditions of temperature of 230 °C, pressure of 170 bar, a feed space velocity of 1.0 hr-1 and gas to oil ratio of 900 nm3/m3 to improve cold flow properties while minimizing aromatics
[0095] The final product is then fractionated to yield NS1, NS2, NS3 and NS4, each with an appropriate boiling range, cold flow properties, and viscosity, making them suitable for various applications as outlined in Table 1.

 
Table-1: Characterization of feed and product.
Property (unit) Feed Combined liquid product Product 1
(NS 1) Product 2 (NS 2) Product 3 (NS 3) Product 4 (NS 4)
Sulfur (ppm) 650 14.7 < 5 < 5 < 10 < 10
Nitrogen (ppm) 85 2 <1 <1 <1 <1
Density at 20 °C (gm/cm³) 0.9302 0.8599 0.8440 0.8654 0.8874 0.9015
Kin. Viscosity at 40 °C (mm²/s) 2.99 2.93 2.05 3.45 6.5 11.25
Pour point (°C) 20 -65 -80 -72 -60 -50
Total Aromatics (wt%) >45 <10 <2 <2 <6 <10
Polyaromatic (wt%) <40 < 2 <1 <1 <3 <4
H/C wt% 12 16
Boiling range (oC) 190-500 200-480 200-240 240-280 280-320 320-410

Example 2:
The treated VGO, as described in Example 1, is then subjected to fluidized bed catalytic cracking at 520°C, resulting in the formation of F1 (boiling range 150-320 degC) and F2 ( boiling range 300-450 degC) distilled fractions. Fractions F1 and F2 along with hydrotreated VGO boiling in the range of 350-520 oC and ARD boiling in the range of 220-340 oC are subsequently blended in suitable proportions. The blended feedstock suitable for downstream processing is prepared by mixing F1, F2, ARD and hydrotreated VGO in the range of 20-50 wt%, 20-50wt%, 20-30 wt% and 20-30 wt% respectively. Characterization of the blended feedstock, as presented in Table 2, reveals the presence of total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content in the range of 1000 ppm.
[0096] Feed mixture is subjected to first stage hydrogenation in the presence of hydrogen using gama-alumina supported (10-20 wt%) Ni/Mo (1:1) as active metal component at process conditions of temperature of 360 °C, pressure of 100 bar hydrogen pressure, a feed weight hour space velocity of 0.9 hr-1 and gas to oil ratio of 1000 nm3/m3. The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor with hydro-isomerization catalyst with platinum loaded on ZSM-22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization were temperature of 330 °C, pressure of 160 bar of hydrogen pressure, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 800 nm3/m3.
[0097] The liquid product mixture from second stage hydrogenation is subjected to third stage hydrogenation or hydro-saturation. Hydro-saturation carried out on silica-alumina mixed oxide supported catalyst with platinum-palldium as active metal component and in the presence of hydrogen to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 160 bar of hydrogen pressure, a feed space velocity of 1.0 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product from stage 3 reactor is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications, as detailed in Table 2.
Table-2: Characterization of feed and product.
Property (unit) Feed Combined liquid product Product 1
(NS 1) Product 2 (NS 2) Product 3 (NS 3) Product 4 (NS 4)
Sulfur (ppm) 650 20 < 5 < 5 < 10 < 15
Nitrogen (ppm) 75 2 <1 <1 <1 <1
Density at 20 °C (gm/cm³) 0.9382 0.8639 0.8495 0.8754 0.8974 0.9195
Kin. Viscosity at 40 °C (mm²/s) 3.5 3.2 2.35 3.75 6.95 11.85
Pour point (°C) 25 -62 -72 -67 -57 -48
Total Aromatics (wt%) >45 <10 <2 <2 <4 <6
Polyaromatic (wt%) <40 < 2 <1 <1 <3 <4
H/C wt% 12.7 15.8
Boiling range (°C ) 150-550 200-510 200-240 240-280 280-320 320-410

Example 3:
[0098] The treated VGO, as described in Example 1, is then subjected to fluidized bed catalytic cracking at 520°C, resulting in the formation of F1 (boiling range 150-320 degC) and F2 ( boiling range 300-450 oC) distilled fractions. Fractions F1 and F2 along with hydrotreated VGO boiling in the range of 350-520 oC are subsequently blended in suitable proportions. The streams F1, F2 and hydrotreated VGO mixed in the range of 30-50 wt%, 30-50wt% and 30-45 wt% respectively and the mixed stream is subjected to fractionator V1 to to obtain suitable feedstock for downstream processing.
[0099] Characterization of the blended feedstock, as presented in Table 3, reveals the presence of total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content in the range of 1000 ppm.
[00100] Feed mixture is subjected to first stage hydrogenation in the presence of hydrogen using gama-alumina supported (10-20 wt%) Ni/Mo (1:1) as active metal component at process conditions of temperature of 360 °C, pressure of 100 bar hydrogen pressure, a feed weight hour space velocity of 0.9 hr-1 and gas to oil ratio of 1000 nm3/m3. The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor with hydro-isomerization catalyst with platinum loaded on ZSM-22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization were temperature of 330 °C, pressure of 160 bar of hydrogen pressure, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 800 nm3/m3.
[00101] The liquid product mixture from second stage hydrogenation is subjected to third stage hydrogenation or hydro-saturation. Hydro-saturation carried out on silica-alumina mixed oxide supported catalyst with platinum-palldium as active metal component and in the presence of hydrogen to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 160 bar of hydrogen pressure, a feed space velocity of 1.0 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product from stage 3 reactor is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications, as detailed in Table 2.
Table-3: Characterization of feed and product.
Property (unit) Feed Combined liquid product Product 1
(NS 1) Product 2 (NS 2) Product 3 (NS 3) Product 4 (NS 4)
Sulfur (ppm) 800 22 < 5 < 5 < 10 < 15
Nitrogen (ppm) 85 2 <1 <1 <1 <1
Density at 20 °C (gm/cm³) 0.945 0.8725 0.8315 0.8505 0.8795 0.9015
Kin. Viscosity at 40 °C (mm²/s) 3.95 3.72 2.53 3.92 7.32 11.75
Pour point (°C) 30 -37 -65 -59 -55 -45
Total Aromatics (wt%) >45 <10 <2 <2 <4 <6
Polyaromatic (wt%) <50 < 2 <1 <1 <3 <4
H/C wt% 12.7 15.9
Boiling range ((°C 190-500 200-475 200-240 240-280 280-320 320-410

Example 4:
[00102] The treated VGO, as described in Example 1, is then subjected to fluidized bed catalytic cracking at 520°C, resulting in the formation of F1 (boiling range 150-320 degC) and F2 (boiling range 300-450 oC) distilled fractions. Fractions F1 and F2 along with hydrotreated VGO boiling in the range of 350-520 oC are subsequently blended in suitable proportions. The blended feedstock suitable for downstream processing is prepared by mixing F1, F2 and hydrotreated VGO in the range of 30-50 wt%, 30-50wt% and 20-30 wt% respectively.
[00103] Characterization of the blended feedstock, as presented in Table 4. reveals the presence of total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, nitrogen content of less than 100 ppm and sulfur content in the range of 1000 ppm.
[00104] Feed mixture is subjected to first stage hydrotreatment in the presence of hydrogen using gama-alumina supported (10-20 wt%) Ni/Mo (1:1) as active metal component at process conditions of temperature of 360 °C, pressure of 100 bar hydrogen pressure, a feed weight hour space velocity of 0.9 hr-1 and gas to oil ratio of 1000 nm3/m3. The resultant liquid product from first stage with sulfur less than 50 ppm and nitrogen less than 5 ppm is routed to second stage reactor with hydro-isomerization catalyst with platinum loaded on ZSM-22 in the presence of hydrogen to isomerise paraffin molecules to iso-paraffins. The conditions for hydro-isomerization were temperature of 330 °C, pressure of 160 bar of hydrogen pressure, a feed weight hour space velocity of 1.1 hr-1 and gas to oil ratio of 800 nm3/m3.
[00105] The liquid product mixture from second stage hydrogenation is subjected to third stage hydrogenation or hydro-saturation. Hydro-saturation carried out on silica-alumina mixed oxide supported catalyst with platinum-palldium as active metal component and in the presence of hydrogen to improve cold flow properties at the process conditions of temperature of 230 °C, pressure of 160 bar of hydrogen pressure, a feed space velocity of 1.0 hr-1 and gas to oil ratio of 800 nm3/m3.The resulting product from stage 3 reactor is then fractionated into distinct products—NS1, NS2, NS3, and NS4—each with a specific boiling range, tailored for various applications, as detailed in Table 4.
Table-4: Characterization of feed and product.
Property (unit) Feed Combined liquid product Product 1
(NS 1) Product 2 (NS 2) Product 3 (NS 3) Product 4 (NS 4)
Sulfur (ppm) 800 22 < 5 < 5 < 10 < 15
Nitrogen (ppm) 85 2 <1 <1 <1 <1
Density at 20 °C (gm/cm³) 0.9505 0.8695 0.8385 0.8585 0.8825 0.9055
Kin. Viscosity at 40 °C (mm²/s) 4.15 3.93 2.77 4.25 8.22 11.95
Pour point (°C) 33 -36 -66 -60 -57 -42
Total Aromatics (wt%) >45 <10 <2 <2 <4 <6
Polyaromatic (wt%) <50 < 2 <1 <1 <3 <4
H/C wt% 12.7 15.9
Boiling range ((°C 150-550 200-522 200-240 240-280 280-320 320-410

[00106] The foregoing examples are merely illustrative and are not to be taken as limitations upon the scope of the invention. Various ch\anges and modifications to the disclosed embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the scope of the invention.

ADVANTAGES OF THE PRESENT INVENTION
[00107] The process generates naphthenic streams with optimized properties, such as low pour points, while ensuring compliance with relevant specifications, independent of the crude feedstock processed in the refinery.
[00108] The process employs Vacuum Gas Oil to hydroprocessing to obtain hydrotreated VGO and aromatic rich diesel (ARD), and hydrotreated VGO further subjects to FCC unit to obtain distilled fractions F1 and F2. The streams F1, F2, ARD and hydrotreated VGO is further blended directly or through fractionation to obtain a feedstock characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatics, This optimized feed composition helps manage exothermicity and enables the production of naphthenic base oils that meet rigorous specifications, including viscosity, pour point, density, sulfur content, and other essential characteristics.
[00109] The process supports comprehensive base oil production, delivering oils with customized properties that are suitable for a broad array of applications, ranging from ink oils to transformer oils.
, Claims:1. A method of production of naphthenic base oils from a feedstock originating from combination of aromatic rich diesel and hydrotreated vacuum gas oil along with its FCC product streams, comprising:
a) hydroprocessing of a vacuum gas oil (VGO), heavy coker gas oil (HCGO) and light coker gas oil (LCGO) in presence of a catalyst to obtain a hydrotreated VGO and aromatic rich diesel (ARD);
b) subjecting a portion of hydrotreated VGO to a fluidized bed catalytic cracking to obtain a distilled fraction F1 and F2 stream;
c) subjecting F1 stream, F2 stream, ARD and hydrotreated VGO in suitable combination as feedstock or subjected to fracationation thereof to create suitable feedstock for further refinement, wherein the feedstock is characterized by total aromatic content exceeding 40 wt%, with polyaromatic hydrocarbons constituting less than 80% of the total aromatic, nitrogen content of less than 100 ppm, and sulfur content of less than 1000 ppm;
d) hydrotreating the feedstock of step c) in the presence of hydrogen and a hydrotreating catalyst under hydrotreating conditions to obtain a first liquid product;
e) hydro-isomerization the first liquid product of step d) in presence of hydrogen and a hydro-isomerization catalyst under hydro-isomerization conditions to obtain a second liquid product;
f) hydro-saturation the second liquid product of step e) in presence of hydrogen and a hydro-saturation catalyst under hydro-saturation conditions to obtain a naphthenic base oils mixture; and
g) fractionating the naphthenic base oils mixture into one or more fractions of naphthenic base oils,
wherein the feedstock obtained in step c) is hydroprocessed through at least one of steps from d) to) f) or combination thereof to obtain the naphthenic base oils mixture.
2. The method as claimed in claim 1, wherein the catalyst in step a) is selected from a group comprising of CoMo, NiMo, NiW and combination thereof.

3. The method as claimed in claim 1, wherein the hydroprocessing in step a) is carried out at a temperature ranging from 300 to 450 °C and 50 to 150 bar hydrogen pressure.

4. The method as claimed in claim 1, wherein the fluidized bed catalytic cracking is carried out in presence of a Y-zeolite catalyst having an amount ranging from 20-45 wt%.

5. The method as claimed in claim 1, wherein the fluidized bed catalytic cracking in step b) is carried out at a temperature ranging from 450 to 600 °C.

6. The method as claimed in claim 1, wherein the distilled fraction F1 stream having a boiling range of 150-320°C and distilled fraction F2 stream having a boiling range of 300-450°C.

7. The method as claimed in claim 1, wherein the remaining hydrotreated VGO and/or aromatic rich diesel (ARD) is combined with portions of fractions F1 and F2 to form a blend stream B1 and the blend stream B1 is either treated directly as feedstock or subjected to fractionation to generate blend 2 (B2) that is suitable for further treatment of preparing napthenic base oil.

8. The method as claimed in claim 1, wherein the hydrotreated VGO, ARD, F1 stream and F2 stream in step c) are mixed in an amount ranging from 20-30 wt%, 25-50 wt%, 30-50 wt% and 20-40wt% respectively.
9. The method as claimed in claim 1, wherein the hydrotreated VGO, F1 stream and F2 stream in step c) are mixed in an amount ranging from 20-40 wt%, 30-50 wt%, 30-50 wt% respectively.

9. The method as claimed in claim 1, wherein the hydrotreating conditions in step d) includes a temperature ranging from 300 to 400 °C, pressure ranging from 80 to 150 bar hydrogen pressure, a feed weight hour space velocity ranging from 0.8 to 1.4 hr-1 and gas to oil ratio ranging from 800 to 1200 nm3/m3.

10. The method as claimed in claim 1, wherein the hydrotreating catalyst in step d) is selected from a group comprising of alumina supported catalyst comprise of nickel, molybdenum, cobalt, tungsten and mixture thereof.

11. The method as claimed in claim 1, wherein the hydro-isomerization condition in step e) includes a temperature ranging from 280 to 380 °C, pressure ranging from 80 to 180 bar, a feed weight hour space velocity ranging from 0.8 to 1.6 hr-1 and gas to oil ratio ranging from 600 to 1000 nm3/m3.

12. The method as claimed in claim 1, wherein the hydro-isomerization catalyst in step e) is selected from a group comprising of platinum loaded on ZSM22, ZSM23, ZSM48 and mixture thereof.

13. The method as claimed in claim 1, wherein the hydro-saturation condition in step f) includes a temperature ranging from 150 to 280 °C, pressure ranging from 110 to 200 bar, a feed weight hour space velocity ranging from 0.8 to 1.6 hr-1 and gas to oil ratio ranging from 500 to 1000 nm3/m3.

15. The method as claimed in claim 1, wherein the hydro-saturation catalyst in step f) is supported catalyst comprises of silica-alumina mixed oxide with nickel or palladium or platinum or combination thereof.

16. The method as claimed in claim 1, wherein the method optionally comprises a step of fractionating the feedstock of step d) to obtain a portion of feedstock that is further hydroprocessed through steps d) to f) to obtain the naphthenic base oils mixture.
17. The method as claimed in claim 1, wherein the steps d) to f) are carried out with minimal exothermic reactions.

18. The method as claimed in claim 1, wherein the naphthenic base oils have a pour point ranging from -40 to -60 °C.

19. The method as claimed in claim 1, wherein the naphthenic base oil composition comprising 100 wppm or less sulfur, 10-30 wt% of paraffinic components, 60 wt% or more of naphthenic components, kinematic viscosity at 40 °C of 2 to 12 cSt, pour point of less than -40 °C and with distillation boiling range of 200-410 °C.

20. The method as claimed in claim 16, wherein the boiling point of the first fraction, second fraction, third fraction and fourth fraction of the naphthenic base oils ranging from 200-240 °C, 240-280 °C, 280-320 °C and 320-410 °C respectively.