Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
  • C10G65/12—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including cracking steps and other hydrotreatment steps

Definitions

• This invention relates to the hydrocrac ing and subsequent catalytic dewaxing of petroleum chargestocks.
• it relates to an integrated fuels hydroprocessing scheme which comprises hydrocracking, distillation, catalytic dewaxing and hydrofinishing steps.
• a dewaxed product of improved viscosity index stability, color and lower volatility is produced.
• the hydrocracker increases the hydrogen content, reduces the viscosity and lowers the boiling range of the hydrocracker charge stock.
• the catalytic dewaxer selectively cracks and/or hydroisomerizes the waxy hydrocrackate.
• the hydrofinisher hydrogenates aromatics and olefins.
• the resulting lube base oil product is water-white, has low aromatics content, low pour point, improved cold flow properties, high viscosity index, low volatility and excellent oxidation stability.
• Mineral oil lubricants are derived from various crude oil stocks by a variety of refining processes directed towards obtaining a lubricant base stock of suitable boiling point, viscosity, pour point, viscosity index (VI) , stability, volatility and other characteristics.
• the base stock will be produced from the crude oil by distillation of the crude in atmospheric and vacuum distillation towers, followed by the removal of undesirable aromatic components by means of solvent refining and finally, by dewaxing and various finishing steps.
• the aromatics may be extracted by solvent extraction using a solvent such as furfural, N- ethyl-2-pyrrolidone, phenol or another chemical which is selective for the extraction of the aromatic components.
• a solvent such as furfural, N- ethyl-2-pyrrolidone, phenol or another chemical which is selective for the extraction of the aromatic components.
• the asphaltenes will first be removed in a propane deasphalting step followed by solvent extraction of residual aromatics to produce a lube generally referred to as bright stock.
• a dewaxing step is normally necessary in order for the lubricant to have a satisfactorily low pour point and cloud point, so that it will not solidify or precipitate the less soluble paraffinic components under the influence of low temperatures.
• Lubricant base stocks of high viscosity index(VI) may be manufactured by the processing of fuels hydrocracker bottoms. This route provides the potential for the manufacture of base stocks with VI of 115 or greater.
• the fuels hydrocracking scheme of the instant invention not only improves VI, but provides a means to meet new international guidelines regarding lower volatility base stocks e.g., ILSAC GF-2.
• the newly proposed volatility requirements require the removal of lighter, lower boiling lube fractions than currently practiced in vacuum distillation procedures for the preparation of lubricant basestocks and this increases their viscosity.
• Yukong Limited has disclosed (International Application PCT/KR94/00046) a method for producing feedstocks of high quality lube base oil from unconverted oil (UCO) of a fuels hydrocracker operating in recycle mode.
• a vacuum distillation unit is employed following fractionation.
• Various cuts of UCO from the vacuum distillation unit (UCO) are then recycled to the hydrocracker reactor.
• any of the fractions from the vacuum distillation unit may be recycled to the first hydrocracker, passed to a second hydrocracker, or even to an FCC unit.
• the cuts from the vacuum distillation unit need not be recycled to the hydrocracker.
• Yukong does not disclose the necessity of operating the fuels hydrocracker to produce waxy fuels hydrocracker bottoms which have the appropriate hydrogen content to obtain subsequently dewaxed basestocks having a VI of at least 115. Yukong claims further dewaxing and stabilization steps in general, but does not describe or claim the specific catalytic dewaxing and subsequent hydrotreating techniques of the instant invention.
• Catalytic dewaxing processes are becoming favored for the production of lubricating oil stocks. They possess a number of advantages over the conventional solvent dewaxing procedures.
• the catalytic dewaxing processes operate by selectively cracking the normal and slightly branched waxy paraffins to produce lower molecular weight products which may then be removed by distillation from the higher boiling lube stock. Concurrently with selective catalytic cracking of waxy molecules, hydroisomerization with the same or different catalyst can convert a significant amount of linear molecules to branched hydrocarbon structures having improved cold-flow properties.
• a subsequent hydrofinishing or hydrotreating step is commonly used to stabilize the product by saturating lube boiling range olefins produced by the selective cracking which takes place during the dewaxing.
• Hydrocarbon Processing (Sept. 1986) refers to Mobil Lube Dewaxing Process, which process is also described in Chen et al "Industrial Application of Shape- Selective Catalysis" Catal.
• the catalyst becomes progressively deactivated as the dewaxing cycle progresses.
• the temperature of the dewaxing reactor is progressively raised in order to meet the target pour point for the product.
• the temperature can be raised before the properties of the product, especially oxidation stability become unacceptable.
• the catalytic dewaxing process is usually operated in cycles with the temperature being raised in the course of the cycle from a low start-of-cycle (SOC) value, typically in the range of 232°C to 274°C (450°F to 525°F) , to a final, end-of cycle (EOC) value, typically 354-385°C (670-725°F) , after which the catalyst is reactivated or regenerated for a new cycle.
• SOC start-of-cycle
• EOC end-of cycle
• dewaxing catalysts which employ ZSM-5 as the active ingredient may be reactivated by hot hydrogen.
• Other dewaxing catalysts may be decoked using air, or oxygen in combination with N 2 or flue gas.
• Catalysts which contain active ingredients, such as ZSM-23 or SAPO-11, that are less active than ZSM-5 containing catalysts may have start-of-cycle (SOC) and end-of-cycle (EOC) temperatures that are 25 to 50°C higher than those that contain ZSM-5.
• SOC start-of-cycle
• EOC end-of-cycle
• the use of a metal hydrogenation component on the dewaxing catalyst has been described as a highly desirable expedient, both for obtaining extended dewaxing cycle durations and for improving the reactivation procedure even though the dewaxing reaction itself is not one which requires hydrogen for stoichiometric balance.
• U.S. Patent No. 4,683,052 discloses the use of noble metal components e.g. Pt or Pd as superior to base metals such as nickel for this purpose.
• a suitable catalyst for dewaxing and isomerizing or hydro-isomerizing feedstocks may contain 0.1-0.6, wt% Pt, for instance, as described in U.S. Pat. No. 5,282,958; 4,859,311; 4,689,138; 4,710,485; 4,859,312; 4,921,594; 4,943,424; 5,082,986; 5,135,638; 5,149,421; 5,246,566; 4,689,138.
• 0.2 to 1 wt.% Pt is preferred, although Pd is also acceptable.
• a series of catalytic reactions may be employed for severely hydrotreating, converting and removing sulfur and nitrogen contaminants, hydrocracking and isomerizing components of the lubricant charge stock in one or more catalytic reactors.
• Polynuclear aromatic feedstocks may be selectively hydrocracked by known techniques to open polynuclear rings. This can be followed by hydrodewaxing and/or hydrogenation (mild hydrotreating) in contact with different catalysts under varying reaction conditions.
• An integrated three-step lube refining process disclosed by Garwood et al, in U.S. Patent No. 4,283,271 is adaptable according to the present invention.
• the average gas-liquid volume ratio in the catalyst zone is about 1:4 to 20:1 under process conditions.
• the liquid is supplied to the catalyst bed at a rate to occupy about 10 to 50% of the void volume.
• the volume of gas may decrease due to the depletion of reaction H as the liquid feedstock and gas pass through the reactor. Production of vapors from formation of methane, ethane, propane and butane from the dewaxing reactions, adiabatic heating or expansion can also affect the volume.
• Vacuum gas oils, light cycle oils or even deasphalted oils may be hydrocracked in a fuels hydrocracker scheme which comprises a downstream vacuum distillation unit.
• Catalytic dewaxer feedstocks having hydrogen above about 13.5 wt.% are produced from the fuels hydrocracker and subsequently dewaxed, hydrofinished and distilled. At least 50 weight percent of the feedstock is converted to hydrocarbon products which boil below the initial boiling point of the feedstock.
• the improved process comprises the steps of:
• a dewaxed lubricant oil product (which boils above about 370°C) is obtained.
• the dewaxed oil product has less than 5 wt% aromatics and enhanced oxidative stability, UV light stability and thermal stability.
• the product possesses a NOACK number of 20 or lower and a VI of 115 or higher. Viscosities are in the range from 3 to 10 cSt at 100°C.
• the preferred hydrodewaxing catalyst comprises a molecular sieve having pores comprised of 10 oxygen atoms alternating with predominantly silicon atoms, such as aluminosilicate zeolites having the structure of ZSM-5, ZSM-23, or ZSM-35 or ZSM-48. Other non-zeolitic molecular sieves, such as SAPO-11, having similar pore size are also suitable catalysts. With the exception of ZSM-5, it is desirable that the catalyst comprise from 0.1 to 1 wt. % noble metal.
• the preferred hydrofinishing catalyst to be employed subsequent to dewaxing comprises at least one Group VIIIA metal and one Group VIA metal (IUPAC) on a porous solid support or Pt or Pd on a porous solid support.
• IUPAC Group VIA metal
• a bimetallic catalyst containing nickel and tungsten metals on a porous alumina support is a good example.
• the support may be fluorided.
• VGO and HVGO normally contain significant levels of polycyclic aromatics.
• VGO and HVGO normally contain significant levels of polycyclic aromatics.
• the waxy material to be catalytically dewaxed usually has a VI of at least 125, preferably 130 or greater, contains about 1 to 15 wt% aromatic hydrocarbons, has a 10 vol% boiling point above about 315°C (600°F) , and contains no more than 30 ppm nitrogen. It has a hydrogen content above about 14.0 wt%. At 100°C, it has a viscosity of greater than 3 cS.
• the hydrodewaxed effluent is hydrofinished and distilled, then is separated to recover a lubricant product which boils above 370°C (698°F) having kinematic viscosity (KV) in the range from 10 to 160 cSt at 40°C or 3 to 10 cSt at 100°C.
• the product lube oil has a UV absorptivity at 325 nm of less than 0.001 L/g-cm (L represents liters) and an aromatics content of 5 wt% or lower.
• the dewaxing stage and hydrofinishing stage are operated at substantially the same pressure, and the entire dewaxed oil stream from the dewaxing stage can be passed directly to the hydrofinishing stage in a cascade operation.
• Figure 1 is a schematic diagram of a fuels hydrocracker suitable for use in the instant invention.
• a hydrotreater, hydrocracker, separator, vacuum distillation unit and hydrofinisher are illustrated. Unconverted material from the fractionation unit may be recycled to the hydrocracker or may be sent to the vacuum distillation unit to be appropriately cut for feed to the catalytic dewaxing reactor.
• Figure 2 is a simplified diagram showing a series of vertical reactors with fixed catalyst beds, showing major flow streams
• Figure 3 demonstrates the relationship between boiling point and viscosity for pure components and vacuum gas oils from Arab light crude.
• Figure 4 presents a comparison of the features of small pore, medium pore and large pore zeolites, or molecular sieves
• Figures 5 through 21 are graphic plots of product properties comparing various process parameters for the improved process and lube products.
• the hydrocarbon feedstock to the integrated process of this invention is a lube range feed with an initial boiling point and final boiling point selected to produce a lube stock of suitable lubricating characteristics.
• These feedstocks are predominantly hydrocarbons having a 10% distillation point greater than 345°C (653°F) and a viscosity of from about 3 to about 40 centistokes at 100°C as can be determined from Figure 3 or similar correlations.
• the feed is conventionally produced by the vacuum distillation of a fraction from a crude source of suitable type. Generally, the crude will be subjected to an atmospheric distillation and the atmospheric residuum (long resid) will be subjected to vacuum distillation to produce the initial unrefined lube stocks.
• the vacuum distillate stocks or "neutral" stocks and bright stocks from propane deasphalting the vacuum distillation bottoms are used to produce a range of viscosity products. Viscosities typically may be 4 centistokes at 100°C for a light neutral, about 12 centistokes at 100°C for a heavy neutral, and about 40 centistokes at 100°C for bright stock.
• the feedstocks are subjected to solvent extraction to improve their V.I. and other qualities by selective removal of the aromatics using a solvent which is selective for aromatics such as furfural, phenol, or N-methyl-pyrrolidone.
• the unrefined vacuum distillates and propane deasphalted (PDA) raffinates are refined by hydrocracking or severe hydrotreating to convert undesirable aromatic and heterocyclic compounds to more desirable naphthenes and paraffins. (See Example 3 infra) . These refined waxy mixtures are low in sulfur and nitrogen contents and after distillation may be adjusted for viscosity as described earlier.
• Integrated all-catalytic lubricant production processes employing hydrocracking and catalytic dewaxing are described in U.S. Patents Nos.
• the hydrocracking process operates with a heavy hydrocarbon feedstock such as virgin light vacuum gas oil, heavy vacuum gas, and deasphalted raffinate, or combination of these, all boiling above about 340°C.
• a heavy hydrocarbon feedstock such as virgin light vacuum gas oil, heavy vacuum gas, and deasphalted raffinate, or combination of these, all boiling above about 340°C.
• these virgin oils are preferred, cracked stocks such as light and heavy coker gas oils and light and heavy FCC gas oils may be added in amounts not to exceed 20% because of their low hydrogen contents. (They are highly aromatic).
• lube oils are generally sold according to their viscosities and because hydrocracking reduces viscosity, the feedstock to the hydrocracker must preferably have a kinematic viscosity at 100°C, of 3 cS or greater.
• the fused ring aromatics and naphthenes are cracked by the acidic catalyst and the paraffinic cracking products, together with paraffinic components of the initial feedstock, undergo conversion to iso-paraffins with some cracking to lower molecular weight materials.
• Hydrogenation of the polycyclic aromatics is catalyzed by the hydrogenation component and facilitates cracking of these compound ⁇ .
• Hydrogenation of unsaturated side chains on the monocyclic cracking residues of the original polycyclic compounds provides substituted monocyclic aromatics which are highly desirable end products.
• the heavy hydrocarbon oil feedstock will normally contain a substantial amount boiling above 340°C (644°F) and have a viscosity above 3cS at 100°C.
• Cycle oils from catalytic cracking operations (FCC) and coking operations are not particularly useful for producing lube oils because they are so highly unsaturated but they may be blended into the virgin oils described above as long as they meet the same boiling and viscosity requirements described for the virgin oils. It is advisable that the hydrocracker feed stock not contain more than 20% cracked stock. The hydrocracker feedstock must comprise 80% or higher virgin components.
• a preliminary hydrotreating step using a conventional hydrotreating catalyst to remove nitrogen and sulfur and to saturate aromatics to naphthenes without substantial boiling range conversion will usually improve catalyst performance and permit lower temperatures, higher space velocities, lower pressures or combinations of these conditions to be employed.
• Suitable hydrotreating catalysts generally comprise a metal hydrogenation component, usually a Group VIB, or VIII metal as described above e.g. cobalt-molybdenum, nickel-molybdenum, on a substantially non-acidic porous support e.g. silica-alumina or alumina. These are listed in Table 1. Table 1
• FIG. 1 is a simplified illustration of the preferred reactor system for the fuels hydrocracker of this invention.
• a preliminary hydrotreating step using a conventional hydrotreating catalyst to remove nitrogen, sulfur, and oxygen, and to saturate olefins and aromatics without substantial boiling range conversion will usually improve the hydrocracking catalyst performance and permit higher space velocities, lower pressures, or combinations of these conditions to be employed.
• Suitable hydrotreating catalysts generally comprise a metal hydrogenation component, usually from Groups VIII and VIB, such as cobalt-molybdenum or nickel-molybdenum, on a low-acidity porous support such as silica-alumina or alumina.
• Appropriate commercial hydrotreating catalysts suitable for use in the instant invention include alumina supported nickel-molybdenum catalysts, such as UOP HCH, Crossfield 594, and Criterion HDN60, and USY supported nickel- molybdenum catalysts, such as UOP HC-24.
• a vertical reactor shell 10 encloses and supports a stacked series of fixed porous solid beds of hydrotreating catalyst, as depicted by 12A through 12E.
• a chargestock 6 comprising vacuum gas oil, light cycle oil, deasphalted oil or any combination of these is combined with a hydrogen- rich gas 8 and introduced to the reactor 10 after undergoing appropriate heating means 9.
• the combined chargestock and hydrogen-rich gas flow downwardly through the catalyst beds.
• 5 beds are depicted in this example, there may be more beds or as few as two. Liquid distribution in each bed is achieved by any conventional technique, such as distributor trays 13A, B, C, D, E, which project the liquid uniformly onto the catalyst bed surfaces 12A, B, C, D, E.
• the gas and liquid phases are introduced into the reactor at a desired inlet pressure and temperature.
• the gas and liquid temperature may be adjusted between catalyst beds by the addition of hydrogen- rich quench gas 14A, B, C, D or alternatively by heat exchange of the liquid in an external flow loop, thereby allowing independent control of the temperature in any catalyst bed.
• a static mixer 15A, B, C, D or other suitable contacting device may be used to mix the liquid and gas streams between catalyst zones, including quench gas, to obtain a homogeneous temperature.
• the hydrotreater effluent 16 passes through heat exchangers (not shown) , separators 18 and stripping or fractionation equipment 20 to separate a recycle gas stream 22 and light conversion products 24. These separations remove byproduct NH 3 and H 2 S, which would otherwise poison the hydrocracking catalyst downstream.
• a purge gas stream 28 would typically be withdrawn from the recycle gas to remove light hydrocarbon products. Gas scrubbing facilities (not shown) would typically be used to remove
• a vertical reactor shell 34 encloses and supports a stacked series of fixed porous solid beds of hydrocracking catalyst, as depicted by 36A through 36E.
• the hydrocracking catalyst which may be more than one catalyst, either admixed or in separate beds, is discussed infra.
• the hydrotreater bottoms product 30 is combined with a hydrogen-rich gas 32 and introduced to the hydrocracking reactor 34 after undergoing appropriate heating means 33. The combined chargestock and hydrogen- rich gas flow downwardly through the catalyst beds. Although 5 beds are depicted in this example, there may be more beds or as few as two.
• Liquid distribution in each bed is achieved by any conventional technique, such as distributor trays 37A, B, C, D, E, which project the liquid uniformly onto the catalyst bed surfaces 36A, B, C, D, E.
• the gas and liquid phases are introduced into the reactor at a desired inlet pressure and temperature.
• the gas and liquid temperature may be adjusted between catalyst beds by the addition of hydrogen-rich quench gas 38A, B, C, D or alternatively by heat exchange of the liquid in an external flow loop, thereby allowing independent control of the temperature in any catalyst bed.
• a static mixer 39A, B, C, D or other suitable contacting device may be used to mix the liquid and gas streams between catalyst zones, including quench gas, to obtain a homogeneous temperature.
• the hydrocracker effluent 38 passes through heat exchangers (not shown) , separators 40 and fractionation equipment 42 to separate a recycle gas stream 44 and converted hydrocracked fractions 46.
• a purge gas stream 50 would typically be withdrawn from the recycle gas to remove light hydrocarbon products.
• Gas scrubbing facilities (not shown) would typically be used to remove NH 3 and H 2 S from the recycle gas stream.
• Makeup hydrogen 48 is added to compensate for hydrogen consumed in the hydrocracking reactions and purged in the gas and liquid product streams 50 and 46.
• the unconverted bottoms product 52 proceeds to the lube vacuum distillation unit 54, one of the novel features of the instant invention.
• This additional distillation step enables the production of various narrow lube fractions 56, 58, 60, 62, 64 of specific viscosity (e.g., 60N, 100N, 150N) and volatility. Low volatility lube stocks with a VI of at least 115 can be produced. Although five lube cuts are shown, there may be more or as few as two. These lube fractions, are passed from the vacuum distillation unit 54 to the catalytic dewaxing process as illustrated in Figure 2.
• the catalyst used in the present hydrocracking process may be a conventional hydrocracking catalyst which employs an acidic large pore size zeolite within the porous support material with an added metal hydrogenation/dehydrogenation function.
• Specific commercial hydrocracking catalysts which may be used include UOP HC-22, and UOP HC-24. These are NiMo catalysts on a support of USY. ICR209, a Chevron catalyst which comprises Pd on a USY support, may also be employed. Table 2 lists suitable hydrocracking catalysts.
• the acidic functionality in the hydrocracking catalyst is provided either by a large pore, amorphous material such as alumina, silica-alumina or silica or by a large pore size crystalline material, preferably a large pore size aluminosilicate zeolite such as zeolite X, Y, ZSM-3, ZSM- 18, ZSM-20 or zeolite beta.
• the zeolites may be used in various cationic and other forms, preferably forms of higher stability so as to resist degradation and consequent loss of acidic functionality under the influence of the hydrothermal conditions encountered during the hydrocracking.
• forms of enhanced stability such as the rare earth exchanged large pore zeolites, e.g. REX and REY are preferred, as well as the so-called ultra stable zeolite Y (USY) and high silica zeolites such as dealuminized Y or dealuminized mordenite.
• Zeolite ZSM-3 is disclosed in U.S. Pat. No. 3,415,736, zeolite ZSM-18 in U.S. Pat. No. 3,950,496 and zeolite ZSM- 20 in U.S. Pat. No. 3,972,983, to which reference is made for a description of these zeolites, their properties and preparations.
• Zeolite USY is disclosed in U.S. Pat. No.
• Hydrocracking catalysts comprising zeolite beta are described in EP94827 and U.S. Pat. No. 4,820,402, to which reference is made for a description of such catalysts.
• the catalysts preferably include a binder such as silica, silica/alumina or alumina or other metal oxides e.g. magnesia, titania, and the ratio of binder to zeolite will typically vary from 10:90 to 90:10, more commonly from about 30:70 to about 70:30 (by weight) .
• a binder such as silica, silica/alumina or alumina or other metal oxides e.g. magnesia, titania, and the ratio of binder to zeolite will typically vary from 10:90 to 90:10, more commonly from about 30:70 to about 70:30 (by weight) .
• This hydrocracking Process is carried out under conditions similar to those used for conventional hydrocracking. Process temperatures of about 260° to 480°C (500°F to 896°F) may conveniently be used although temperatures above about 445°C (833°F) will normally not be employed since the thermodynamics of the hydrocracking reactions becomes unfavorable at temperatures above this point. Generally, temperatures of about 315°C to 425 C C (599° to 797°F) will be employed. Total pressure is usually in the range of 1200 to 3000 psi (8274 to 20,685 kPa) and the higher pressures within this range over 1800 psi (12,600 kPa) will normally be preferred.
• the process is operated in the presence of hydrogen and hydrogen partial pressures will normally be at least 1200 psig (8274 kPa) .
• the ratio of hydrogen to the hydrocarbon feedstock (hydrogen circulation rate) will normally be from 2000 to 5000 SCF/Bbl. (about 18 to 980 n.1.1 "1 ).
• the space velocity of the feedstock will normally be from 0.1 to 10 LHSV (hr- 1) , preferably 0.5 to 5 LHSV.
• the n- paraffins in the feedstock will be isomerized to iso ⁇ paraffins but at higher conversion under more severe conditions the iso-paraffins will be converted to lighter materials.
• the conversion may be carried out by contacting the feedstock with a fixed stationary bed of catalyst.
• a simple configuration is a trickle-bed operation in which the feed is allowed to trickle through a stationary fixed bed ( Figure 1 illustrates this) .
• the hydrocracking catalyst may be regenerated by contact at elevated temperature with hydrogen gas, for example, or by burning in the presence of a mixture of air, nitrogen and flue gas.
• FIG. 2 illustrates a specific embodiment of the instant invention and is not intended to be limiting.
• a vertical reactor shell 10 encloses and supports a stacked series of fixed porous solid beds of dewaxing catalyst, as depicted by 12A through 12C.
• a chargestock 6 comprising wax-containing liquid oil is combined with a hydrogen-rich gas 8 and introduced to the reactor 10 after undergoing appropriate heating means 9.
• the combined chargestock and hydrogen-rich gas flow downwardly through the catalyst beds.
• 3 beds are depicted in this example, there may be more beds or as few as two.
• Liquid distribution is achieved by any conventional technique, such as distributor trays 13A, B, C, which project the liquid uniformly onto the catalyst bed surfaces 12A, B, C.
• the gas and liquid phases are introduced into the reactor at a desired inlet pressure and temperature.
• the gas and liquid temperature may be adjusted between catalyst beds by the addition of hydrogen-rich quench gas 14A, B or alternatively by heat exchange of the liquid in an external flow loop, thereby allowing independent control of the temperature in any catalyst bed.
• a static mixer 15A, B or other suitable contacting device may be used to mix the liquid and gas streams between catalyst zones, including quench gas, to obtain a homogeneous temperature.
• the hydrodewaxing reactor effluent 24 is heated or cooled, as necessary via heat exchange or furnace 25 and cascaded directly into the hydrofinishing reactor 30.
• a vertical reactor shell 30 encloses and supports a stacked series of fixed porous solid beds of hydrofinishing catalyst, as depicted by 32A through 32C. The liquid and gas flow downwardly through the catalyst beds. Although 3 beds are depicted in this example, there may be more beds or as few as two. Liquid distribution is achieved by any conventional technique, such as distributor trays 33A, B, -20-
• the gas and liquid phases are introduced into the reactor at a desired inlet pressure and temperature.
• the gas and liquid temperature may be adjusted between catalyst beds by the addition of hydrogen- rich quench gas 34A, B or alternatively by heat exchange of the liquid in an external flow loop, thereby allowing independent control of the temperature in any catalyst bed.
• a static mixer 35A, B or other suitable contacting device may be used to mix the liquid and gas streams between catalyst zones, including quench gas, to obtain a homogeneous temperature.
• the hydrofinisher effluent 36 passes through heat exchangers (not shown) , separators 40 and fractionation equipment 42 to separate a recycle gas stream 44, converted fractions 46, and a finished lube base stock 48.
• a purge gas stream 50 would typically be withdrawn from the recycle gas to remove light hydrocarbon products.
• Gas scrubbing facilities (not shown) would typically be used to remove NH 3 and H 2 S from the recycle gas stream.
• Makeup hydrogen 52 is added to compensate for hydrogen consumed in the hydrodewaxing and hydrotreating reactions and purged in the gas and liquid product streams 50 and 46.
• the continuous multi-stage reactor system has been described for contacting gas and liquid phases with a series of porous catalyst beds; however, it may be desired to have other reactor configurations with 2-5 beds.
• the catalyst composition may be the same in all beds of each reactor; however, it is within the inventive concept to have different catalysts and reaction conditions in the separated beds. Design and operation can be adapted to particular processing needs according to sound chemical engineering practices.
• the present technique is adaptable to a variety of catalytic dewaxing operations, particularly for treatment of lubricant-range heavy oils with hydrogen-containing gas at elevated temperature.
• the catalyst bed has a void volume fraction greater than 0.25. Void fractions from 0.3 to 0.5 can be achieved using loosely packed polylobal or cylindrical extrudates, spheres or pellets providing adequate liquid flow rate component for uniformly wetting catalyst to enhance mass transfer and catalytic phenomena. Catalyst bed depths may range from 2 to 6 meters.
• a waxy lube feedstock typically a 321°C+ (about 610°F-f-) feedstock is subjected to an intermediate pore size molecular sieve catalyst having dewaxing and/or isomerization or hydroisomerization functions in the presence of hydrogen to produce a dewaxed lube boiling range product of low pour point (ASTM D-97 or equivalent method such as Autopour) .
• ASVM D-97 or equivalent method such as Autopour
• the hydrogen feedrate at the top of the dewaxing reactor is about 267-534 n.l.l.-l (1500-3000 SCF/BBL) .
• a hydrofinishing step is generally carried out.
• the catalytic dewaxing process step is operated under conditions of elevated temperature, usually ranging from about 205° to 400°C (401° to 752°F) , preferably from 235° to 385°C (455° to 725°F) , depending on the dewaxing severity necessary to achieve the target pour point for the product.
• elevated temperature usually ranging from about 205° to 400°C (401° to 752°F) , preferably from 235° to 385°C (455° to 725°F) , depending on the dewaxing severity necessary to achieve the target pour point for the product.
• the temperature may be 25 to 50°C higher than for ZSM-5.
• the severity of the dewaxing process is increased by raising the reactor temperature so as to effect an increasingly greater conversion of normal paraffins, so that lube yield will generally decrease with decreasing product pour point as successively greater amounts of the normal paraffins (wax) in the feed are converted by selective cracking by the dewaxing catalyst to lighter products boiling outside the lube boiling range.
• the V.I. of the product will also decrease as pour point is lowered because the high V.I. normal paraffins and slightly branded isoparaffins are progressively converted.
• the dewaxing temperature is increased during each dewaxing cycle to compensate for decreasing catalyst activity due to catalyst aging.
• the dewaxing cycle will normally be terminated when a temperature of about 400°C (about 750°F) , but preferably about 385°C
• Coke is a highly carbonaceous hydrocarbon which tends to accumulate on the catalyst during the dewaxing process.
• the process is therefore carried out in the presence of hydrogen, typically at about 2758 to 20,685 kPa hydrogen partial pressure (400 to 3000 psia) , preferably between 9653 to 17238 kPa (1400 to 2500 psi) more preferably between 1600 to 2200 psi (11032 to 15169 kPa) although higher pressures can be employed.
• Hydrogen circulation rate is typically 180 to 710, usually 355 to 535 n.1.1.
• the preferred hydrodewaxing catalyst comprises a porous acid molecular sieve having pores comprised of 10 oxygen atoms alternating with predominantly silicon atoms, such as aluminosilicate zeolite.
• Most prominent among these intermediate pore size zeolites are ZSM-5, ZSM-23, ZSM-35 and ZSM-48 which are usually synthesized with Bronsted acid active sites by incorporating a tetrahedrally coordinated metal, such as Al, Ga, or Fe, within the zeolitic framework.
• Medium pore molecular sieves having pore dimensions about 3.9 to 6.3 Angstroms are favored for shape selective acid catalysis; however, the advantages of medium pore structures may be utilized by employing highly siliceous materials or crystalline molecular sieve having one or more tetrahedral species having varying degrees of acidity. These shape selective materials have at least one channel with pores formed by ten-member rings containing ten oxygen atoms alternating with silicon and/or metal atoms.
• the catalysts which have been proposed for shape selective catalytic dewaxing processes have usually comprised molecular sieves which have a pore size which admits the straight chain, waxy n-paraffins either alone or with only slightly branched chain paraffins but which exclude more highly branched materials and cycloaliphatics.
• Representative of the medium pore molecular sieves are ZSM- 5 (US Pat. No. 3,702,886), ZSM-11 (US Pat. No. 3,709,979) , ZSM-22, ZSM-23 (US Pat. No. 4,076,842) , ZSM-35 (US Pat. No. 4,016,245) , ZSM-48 (US Pat. No.
• ZSM-24 is a synthetic ferrierite. (See Fig. 4) The disclosures of these patents are herein incorporated by reference.
• Molecular sieves offer advantages in catalytic dewaxing over noncrystalline catalysts. Molecular sieves are broadly classed into small, medium (or intermediate), and large pore materials as shown in Figure 4. The pore size is fixed by a ring of oxygen atoms. Small pore zeolites have eight-membered ring openings, medium have ten-membered systems and large have twelve-membered systems. Catalytic dewaxing performance can also be affected by the catalyst's pore structure, whether it has uni- or bi-dimensional channels, and the nature of its channel intersections. Severely constrained, small pore zeolites are ineffective in lube oil dewaxing because they allow only small, normal paraffins to penetrate the pore channel.
• HZSM-5 is one of a number of medium pore size zeolites which are capable of shape-selective dewaxing. Other examples include ZSM-11, ZSM-22, ZSM-23, ZSM-35, ZSM-48 and ZSM-57.
• the pore structure of ZSM-5 provides a balance of reactant shape selectivity, reduced coking tendency and exclusion of bulky nitrogen-containing catalyst poisons.
• HZSM-5, Pt/ZSM-23, Pd/ZSM-23, Pt/ZSM-48 and Pt/SAPO-11 with appropriately adjusted physicochemical properties are preferred in the instant invention because their channel systems and pore dimensions enable effective de-waxing of fuels hydrocracker bottoms.
• Suitable molecular sieves having a coordinated metal oxide to silica molar ratio of 20:1 to 200:1, or higher may be used.
• HZSM-5 for example, it is advantageous to employ conventional aluminosilicate ZSM-5 having a silica:alumina molar ratio of about 25:1 to 70:1 although ratios above 70:1 may be used.
• a typical zeolite catalyst component having Bronsted acid sites may consist essentially of crystalline aluminosilicate having the structure of ZSM-5 zeolite with 5 to 95 wt.% silica, clay and/or alumina binder. It is understood that other medium pore acidic molecular sieves, such as salicylate, silica- aluminophosphate (SAPO) materials may be employed as catalysts, especially medium pore SAPO-11.
• SAPO silica- aluminophosphate
• U.S. Pat. No. 4,908,120 (Bowes et al) discloses a catalytic process useful for feeds with high paraffin content or high nitrogen levels.
• the process employs a binder free zeolite dewaxing catalyst, preferably ZSM-5.
• Medium pore zeolites are particularly useful in the process because of their regenerability, long life and stability under the extreme conditions of operation.
• the zeolite crystals have a crystal size from about 0.01 to over 2 microns or more, with 0.02-1 micron being preferred.
• ZSM-5 ( 40 alpha) can be used in its metal-free form for selective cracking, in the case of the other medium pore acidic metallo-silicates described supra, it is necessary that they be modified with from 0.1 to 1.0 wt.% of a noble metal in order to be used as hydroisomerization dewaxing catalysts.
• ZSM-5 is the only medium pore zeolite or medium pore acidic molecular sieves that is practical to use for commercial selective dewaxing without adding a noble metal.
• the noble metal is required with other medium pore molecular sieves in order to reduce catalyst aging rates to practical levels.
• the addition of a noble metal to ZSM-5 provides it with hydroisomerization activity that increases yields of dewaxed lube oils. It has been found that when noble metals are added to ZSM-23, ZSM-35, SAPO-11 and ZSM-5, the product yields and VI are generally higher for ZSM-23, ZSM-35 and SAPO-11 than for ZSM-5. The choice of which catalyst to use becomes one of economics.
• Catalyst size can vary widely within the inventive concept, depending upon process conditions and reactor structure. Finished catalysts having an average maximum dimension of 1 to 5mm are preferred.
• the catalyst employed is 65 wt% ZSM-5 having an acid cracking (alpha) value of 105, and formed as 1.6 mm diameter extrudate; however, alpha values from about 1 to about 300 may be used.
• Reactor configuration is an important consideration in the design of a continuously operating system.
• a vertical pressure vessel is provided with a series (at least 2) of stacked catalyst beds of uniform cross-section.
• a typical vertical reactor having a total catalyst bed length to average width (L/D aspect) ratio of about 1:1 to 20:1 is preferred. Stacked series of beds may be retained within the same reactor shell; however, similar results can be achieved using separate side-by-side reactor vessels.
• Reactors of uniform horizontal cross section are preferred; however, non ⁇ uniform configurations may also be employed, with appropriate adjustments in the bed flux rate and corresponding recycle rates.
• the invention is particularly useful in catalytic hydrodewaxing of heavy petroleum gas oil lubricant feedstock boiling above 315°C (599°F) .
• the catalytic dewaxing treatment may be performed at an hourly liquid space velocity not greater than 5 hr "1 , preferably about
• the hydrocarbon feedstock to the catalytic dewaxer has a viscosity of 3 to 12 cSt at 100°C.
• the liquid flux rate for total feed rate is maintained in the range of 2441-17088, preferably 4882-14647 kg/m 2 /hr (500-3500 pounds/ft'-hr,
• a hydrofinishing step (see Figure 2) follows catalytic dewaxing in order to saturate lube range olefins as well as to remove heteroatoms, color bodies and, if the hydrofinishing pressure is high enough, to effect saturation of residual aromatics.
• the post-dewaxing hydrofinishing i ⁇ usually carried out in cascade with the dewaxing step.
• the hydrofinishing will be carried out at temperatures from about 230°C to 330°C, preferably 246-274°C and most preferably 260-302°C (450°F to 625°F, 475°F to 600°F and most preferably 500-575°F) .
• Total pressures are typically from 9653 to 20,685 kPa (about 1400 to 3000 psi) .
• Liquid hourly space velocity in the hydrotreater is typically from 0.1 to 5 LHSV (hr "1 ) , preferably 0.5 to 3 hr "1 . Processes employing sequential lube catalytic dewaxing- hydrofinishing are described in U.S. Patents Nos.
• a process employing a reactor with alternating dewaxing-hydrofinishing beds is disclosed in U.S. Patent No. 4,597,854. Reference is made to these patents for details of such processes.
• the hydrofinishing step following the dewaxing step improves product quality without significantly affecting its pour point.
• the metal function on the hydrofinishing catalyst is effective in saturating aromatic components.
• a hydrofinishing (HDF) catalyst with a strong desulfurization/hydrogenation function that a noble metal, nickel-tungsten or nickel-molybdenum can provide will be more effective than a catalyst comprising a weaker metal function such as molybdenum alone.
• the preferred hydrofinishing catalysts for aromatics saturation will comprise at least one metal having relatively strong hydrogenation function on a porous support. Because the desired hydrogenation reactions require little acidic functionality and because no conversion to lower boiling products is desired in this step, the support of the hydrofinishing catalyst is of low acidity. Typical support materials include amorphous or crystalline oxide materials such as alumina, silica, and silica-alumina of low-acidic character. The metal content of the catalyst is often as high as about 20 weight percent for non-noble metals.
• Noble metals are usually present in amount ⁇ no greater than 1.0 wt.%. Hydrofinishing catalysts of this type are readily available from catalyst suppliers.
• the nickel- tungsten catalysts may be fluorided.
• Control of the reaction parameters of the hydrofinishing step offers a useful way of varying the stability of the products.
• hydrofinishing catalyst temperatures of about 230°- 300°C (446°-572°F) will minimize single-ring aromatics and polynuclear aromatics. They will also provide products having good oxidative stability, UV light stability, and thermal stability. Space velocity in the hydrofinisher also offers a potential for aromatics saturation control with the lower velocities effecting greater aromatics saturation.
• the hydrofinished product preferably contains not more than 10 wt% aromatics.
• Example l Table 3 provides an analysis of an atmospheric tower bottoms product from a commercial two stage hydrocracker. Such a hydrocracker possesses a hydrotreater reactor and a hydrocracking reactor, but does not employ the vacuum distillation unit as described in the hydrocracking unit of the instant invention.
• the product is roughly a 330-538°C (625-1000°F) cut and is very low in heteroatom and aromatic content, particularly nitrogen.
• the hydrocracking catalyst employed was fresh.
• a full range analysis of the drum of the atmospheric tower bottoms as received is reported in the "total bottoms" column. The bottoms were broken down into five equal volume cuts and analyzed for key properties. These analyses are also provided in Table 3.
• Viscosity Index > 115 NOACK > 6 ⁇ 20
• Figure 5 illustrates the relationship of Viscosity Index v. Hydrogen content for lube oils having a pour point of -7°C wherein the oils have been refined either by solvent refining or by hydrocracking.
• Each of the various waxy stocks compared was solvent dewaxed to a -7°C pour point.
• the VI viscosity index
• the VI improves somewhat more for hydrocracked stocks than for solvent refined stocks.
• the empty circles represent lubestocks obtained by lubes hydrocracking, distillation and solvent dewaxing without further treatment. Circles containing crossed lines represent lubestocks refined by fuels hydrocracking, distillation and solvent dewaxing.
• dewaxed lubestocks must have a VI of at least 115. From Figure 5, the dewaxed oil product must have a hydrogen content of at least about 14.l wt% in order to obtain a VI of 115.
• the hydrocracker provide a vacuum distillation product having at least 14.3 wt% hydrogen.
• PONA analysis of these hydrocracked lubestocks on Figure 5 demonstrated that they possess wide variations in composition, some having a high paraffinic content and others having a high naphthenic content, others being in between.
• An infinite variety of compositions is therefore possible at any VI level and the variation can be described by a range of hydrogen contents for any VI level.
• the hydrogen content of 150 isoparaffins ranges from 15.1 % to 14.6 % for carbon numbers ranging from C 17 to C 55 , respectively.
• a fuels hydrocracker that is, a hydrocracker that operates in excess of 40% conversion to 345°C minus light products, can produce a 345°C plus product having the appropriate hydrogen content to provide a dewaxed oil having a viscosity index of 115.
• Figure 6 (parts a, b, and c) is a demonstration of lubes hydrocracking and fuels hydrocracking for a heavy vacuum gas oil derived from Statfjord crude oil.
• the heavy vacuum gas oil was hydrocracked in a pilot plant at various conversions and the hydrocrackate was distilled to remove all of the 345°C (653°F) materials.
• the waxy 345°C plus oils were then solvent dewaxed to -18°C (0°F) pour point and the viscosities and VI's were determined.
• the conversion range from 10 to about 30% is referred to as the lubes hydrocracking range and the conversion level from 30% and higher is referred to as the fuels hydrocracking range.
• the same hydrodewaxing catalyst was used for both high and low pressure operation.
• a commercial hydrofinishing catalyst was employed in the second reactor.
• low pressure (2.86 x 10 3 -4.2 x IO 3 kPa) operation the hydrofinishing catalyst is designed only for olefin saturation. Some level of aromatics saturation is necessary for good oxidative and UV light stability, however.
• a hydrofinishing catalyst which operates at high pressure (1.73 x 10 4 kPa) was used for aromatics saturation.
• the hydrofinishing catalyst employed at low pressure was evaluated at 1.53 x 10 4 kPa in order to provide a comparison.
• pour point reduction is twice as responsive to catalytic dewaxing temperature changes at the high pressure, which could facilitate production of very low pour point base stocks, if desired. (See Figure 10)
• Lube yields and VI's are relatively insensitive to pressure (see Figure 11), producing 67-72 wt.% yield of 121 VI, 116 SUS base stock at -15°C pour point (versus 82 wt.%, 129 VI, 107 SUS with solvent dewaxing on a dry wax basis).
• Standard low pressure catalytic dewaxing allowed little adjustment in total aromatics levels as determined by UV absortivity at 226 nm ( Figure 12) .
• Use of an aromatics saturation catalyst at 1.73 x l ⁇ " kPa (2500 psig) allowed reduction of aromatics to equilibrium levels at 274°C (525°F) HDF temperature, as determined by UV absorptivities.
• the low pressure program was run in a two-reactor pilot plant with online N 2 stripping capability.
• Reactor 1 was loaded with 225 cc of dewaxing catalyst, HZSM-5.
• Reactor 2 was loaded with 225 cc of hydrofinishing catalyst (Mo/Al 2 0 3 ) , which is designed for olefin saturation and low desulfurization (critical for maintaining oxidation stability of conventionally-refined lube base stocks) . Both catalysts were 1/16" cylindrical extrudates and were commercially produced.
• the low pressure work was done at 400 psig total pressure using pure H 2 2.9 x IO 3 kPa (415 psi H 2 partial pressure) and 1 LHSV (each reactor), with 1.73 x IO 4 kPa (2500 scf/B) H 2 circulation.
• Three HDF temperatures (241°C, 274°C, and 288°C) were investigated at specification pour point (-15°C) to bracket an optimum treating severity for producing UV light-stable base stock.
• High pressure catalytic dewaxing was performed in a two reactor pilot plant.
• Reactor 1 was loaded with 262 cc of dewaxing catalyst. This catalyst was the same dewaxing catalyst used in the standard pressure run.
• Reactor 2 was loaded with 62 cc of a commercial hydrofinishing catalyst with excellent aromatics saturation capabilities (Arosat) . It is commercially available as a 1/16" quadrulobe extrudate.
• the high pressure catalytic dewaxing was done at 1.73 x 10 4 kPa (2500 psig_ total pressure using pure H 2 1.74 x 10 4 kPa(H 2 partial pressure) and 1 LHSV (each reactor), with 445 n.1.1. (2500 Scf/B H 2 circulation).
• Light stability of the high pressure catalytic dewaxed and hydrotreated base stocks is excellent when the aromatic saturation catalyst is used, with no precipitate after 42 -3 ⁇ - days (see Figure 13) .
• Products from low pressure catalytic dewaxing and hydrofinishing and also from solvent dewaxing have very poor light stability, deteriorating badly and about equally within 2-3 days. This would indicate that the light instability is not a result of anything occurring in the catalytic dewaxing step, but rather a result of unstable components in the hydrocracker bottoms.
• Such instability is generally associated with 3+ ring aromatics, which can be monitored by UV absorptivity at 325 nm.
• RBOT performance of high pressure catalytic dewaxing and low pressure catalytically dewaxed base stocks are comparable and good (see Figure 15) .
• Solvent dewaxed oils from the same commercial feed also performed well, but were marginally lower on average.
• Relative to the catalytic dewaxed stocks, the solvent dewaxed hydrocracked samples were fair to poor, and showed a general trend of decreasing RBOT stability with increasing boiling range (25% bottoms vs. full range hydrocrackate) and increasing hydrocracker catalyst age End of Run (EOR) vs. Start of Run (SOR).
• Table 5 illustrates via extremely low UV absorptivities at 400 nm that polynuclear aromatics (PNA) are largely absent in lubes which have been treated with high pressure catalytic dewaxing followed by hydrofinishing. This correlates to the sunlight stability results on Figure 13.
• PNA polynuclear aromatics
• Example 9 Dewaxing catalyst aging is significantly lower at 1.73 x 10 4 kPa (2500 psig) than it is at 2.8 x 10 3 kPa (400 psi). In addition, lube pour point is 2.3 times more responsive to dewaxing temperature changes at the higher pressure. These differences are attributed to lower rates of coke formation at the higher pressure.
• Catalyst aging is depicted in Figure 10. Hydrodewaxing reactor (reactor 1) temperatures (actual and corrected to 5°F pour point) and pour point are shown versus days on stream. As is typical for low nitrogen stocks, aging rates are low relative to conventional, solvent-refined stocks.
• start of cycle temperature was about 530°F.
• Initial aging rate was -14°C (6.4°F/day) with a transition to a lower aging rate of -15°C (5.65°F/day) .
• a pour point correction of l.3°F pour/l°F change in HD reactor temperature was effective for smoothing out the HDW reactor temperature data for pour points ranging from -30°C to 4°C (-22°F to +39°F) .
• Solvent dewaxing preferentially removes the heavier, higher-pour waxes, whereas catalytic dewaxing with ZSM-5 preferentially cracks the smaller, normal paraffins, which are also the highest VI components.
• catalytic dewaxed light neutral lube yields and VI's are lower.
• Low temperature viscometric performance of formulated catalytic dewaxed products are superior to solvent dewaxed oils of equivalent viscosity, however.
• UV absorptivity was relied on for screening hydrofinishing reactor conditions during the pilot plant studies. Absorptivity at five wavelengths — 226, 254, 275, 325, and 400 nm — are used as qualitative indicators of the amount of aromatics, with 226 nm corresponding to total aromatics. Aromatics with three or more rings and four or more rings are indicated by absorptivities at 325 nm and 400 nm, respectively. Lube aromatics are reduced dramatically over the
• Arosat HDF catalyst The standard catalytic dewaxing HDF catalyst, which is designed for olefin saturation, is much less effective, even at 1.53 x 10 4 kPa (2200 psi) (see Figures 12 and 21).
• UV absorptivity at 226 nm goes through a minimum for the high pressure catalytic dewaxing near 274°C (525°F) — marking the crossover from a kinetically-limited to an equilibrium-limited regime. This minimum should move toward higher HDF temperatures (and higher UV absorptivities) as feed aromatics increase.
• the standard catalytic dewaxing HDF catalyst is kinetically limited for saturating aromatics in the temperature range examined.
• a number of medium pore molecular sieves were tested for their abilities to convert a normal paraffin that is representative of waxes in waxy light lube oil base stocks.
• the normal paraffin was n-hexadecane.
• the molecular sieves that were tested with this compound were ZSM-5, ZSM-23, ZSM-48 and SAPO-11.
• the acid activity of the catalysts was varied for the molecular sieves either in the synthesis of the sieve or by steaming, which is known to reduce the activity of molecular sieves.
• the following table lists the molecular sieves, their platinum contents and their "ALPHA" activities.
• All of these medium pore molecular sieves are capable of high conversions of a waxy compound such as n-hexadecane.
• the activity of the catalyst made from each molecular sieve can be significantly different depending upon the activity of the molecular sieve in the catalyst.
• the platinum content also affects the activity.
• Product selectivities are affected by the type of sieve, platinum content and "ALPHA" activity.
• Figure 21 is a plot of n-hexadecane conversion versus temperature requirements.
• Figure 22 is a plot of the yield of isomeric n-hexadecane conversion compounds having 16 carbon atoms versus hexadecane conversion. This figure shows that ZSM-48 and SAPO-11 give the best selectivity to isoparaffins in general.

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