HK1010561A - Integrated lubricant upgrading process - Google Patents

Description

Integrated lubricant upgrading process

no marking

The present invention relates to hydrocracking and subsequent catalytic dewaxing of petroleum feedstocks. More particularly, the present invention relates to an integrated fuel hydroprocessing scheme that includes hydrocracking, distillation, catalytic dewaxing and hydrofinishing steps. Dewaxed products are produced that have improved viscosity Z index stability, color and lower volatility. The hydrocracker increases the hydrogen content of the hydrocracker feed, reduces viscosity and reduces boiling point range. A catalytic dewaxing unit selectively cracks and/or hydroisomerizes the waxy hydrocracked product. The hydrorefining unit hydrogenates aromatic hydrocarbons and olefins. Which reduces the ultraviolet absorption of the dewaxed oil. The volatility was adjusted by distillation. The resulting lubricant base oil product is water-white, having low aromatic content, low pour point, improved cold flow properties, high viscosity index, low volatility and excellent oxidation stability.

Mineral oil lubricants are obtained from a variety of crude oil feedstocks using various refining processes that directly yield lubricant base stocks of suitable boiling point, viscosity, pour point, Viscosity Index (VI), stability, volatility and other characteristics. Generally, the base stock may be produced from crude oil by distillation of the crude oil in atmospheric and vacuum distillation columns, followed by solvent refining to remove undesirable aromatic components, and finally by dewaxing and various refining steps. Because polycyclic aromatic hydrocarbon components result in poor thermal and light stability, poor color, and extremely poor viscosity index, it is undesirable to use a low hydrogen content crude oil or a bituminous crude oil because the yield of acceptable lubricating oil stock will be extremely low after the substantial amount of aromatic hydrocarbon components contained in the lubricating oil stock are separated from such crude oil. Thus, paraffinic and naphthenic crude oils are preferred, however, it is desirable to treat feedstocks containing polycyclic aromatic hydrocarbons with aromatic hydrocarbon treatment processes to remove undesirable aromatic hydrocarbon components.

In the case of lube oil fractions, which are generally referred to as neutral oils, such as heavy neutral oils and light neutral oils, and the like, aromatics can be extracted by solvent extraction using solvents such as furfural, N-methyl-2-pyrrolidone, phenol, or other chemicals that selectively extract aromatic components. If the lube oil stock is a residual oil stock, the asphaltenes are first removed in a propane deasphalting step, followed by solvent extraction of residual aromatics to produce a lube oil commonly referred to as bright stock. In each case, however, a dewaxing step is generally required in order to provide lubricating oils with satisfactorily low pour and cloud points so that the less soluble paraffinic hydrocarbon components do not solidify or precipitate under the influence of low temperatures.

Lube base oils of high Viscosity Index (VI) can be produced by processing fuel hydrocracker bottoms. This approach offers the potential to produce base stocks having a VI of 115 or higher. The fuel oil hydrocracking scheme of the present invention not only improves VI but also provides a means to meet new international guidelines for lower volatility base stocks such as ILSAC GF-2. This newly proposed volatility condition requires the removal of lighter, lower boiling lubricant oil fractions than are typically obtained in vacuum distillation processes for making lubricant base oils, and this increases their viscosity. Therefore, higher boiling, higher viscosity materials must also be removed in the distillation process in order to maintain viscosity. This generally results in lower yields and narrower lubricant base oil fractions, and this increases their viscosity. As described herein, distillation of the hydrocracking bottoms may also improve the operating performance and efficiency of the hydrocracking column by removing undesirable components such as polycyclic aromatics, since non-lube range materials are returned to the hydrocracking column as recycle (or passed to a second hydrocracking column). The resulting lubricant fraction may then be catalytically dewaxed, hydrotreated, and then distilled to produce a finished lubricant product.

A process for hydrocracking fuel oils with partial liquid recycle is disclosed in U.S. Pat. No. 4,983,273(Kennedy et al). In this process, either the feed (typically Vacuum Gas Oil (VGO)) or Light Cycle Oil (LCO) is processed in a hydrotreating reactor and then processed in a hydrocracking reactor before going to a fractionator. Part of the fractionator bottoms is then recycled to the hydrocracking column. However, it does not suggest fractionating the bottoms to an additional vacuum distillation step, followed by additional hydrotreating or hydrocracking, as in the present invention.

Yukong Limited has disclosed (International application PCT/KR94/00046) a method for producing high quality lube base stock from unconverted oil (UCO) of a fuel oil hydrocracking column operating in recycle mode. As in the present invention, a vacuum distillation apparatus is used after the fractionation. The various UCO fractions obtained from the vacuum distillation Unit (UCO) are then recycled to the reactor of the hydrocracking unit. In the present invention, any fraction of the vacuum distillation unit may be recycled to the first hydrocracking column, passed to the second hydrocracking column, or even fed to the FCC unit. The fraction obtained by the vacuum distillation device does not need to be recycled to the hydrocracking tower. The Yukong application does not disclose that the fuel hydrocracker must be operated to produce a waxy fuel hydrocracker bottoms having a suitable hydrogen content in order to thereafter obtain a dewaxed base stock having a VI of at least 115. Yukong also claims general dewaxing and stabilization steps, however, it does not describe or claim the specific catalytic dewaxing and subsequent hydrotreating techniques of the present invention.

Catalytic dewaxing processes become more advantageous for producing lube oil stocks. These processes have many advantages over conventional solvent dewaxing processes. The catalytic dewaxing process is operated to selectively crack normal and slightly branched waxy paraffins to produce a lower molecular weight product which can then be removed from the higher boiling lube oil stock by distillation. Simultaneously, selective catalytic cracking, isomerization of waxy molecules with the same or different catalysts can convert significant quantities of straight chain molecules into branched chain hydrocarbon structures with improved cold flow. This product is typically stabilized by saturating the olefins in the boiling range of the lube oil resulting from the selective hydrocracking that occurs in the dewaxing process, using a subsequent hydrofinishing or hydrotreating step. For an introduction to these methods, reference is made to U.S. Pat. No. 3,894,938(Gorring et al), 4,181,598(Gillespie et al), 4,360,419(Miller), 5,246,568(Kyan et al) and 5,282,958(Santilli et al). Hydrocarbon Processing (1986.9) relates to the Mobil lube dewaxing process, which is also described in Chen et al, "Industrial Application of Shape-Selective Catalysis" Catal. Rev. Sci. Eng.28(283), 185-264(1986), to which reference is made for further description. See also "Lube Dewaxing Technology and Economics", Hydrocarbon Asia 4(8), 54-70 (1994).

In this type of catalytic dewaxing process, the catalyst becomes progressively deactivated as the dewaxing cycle progresses. To compensate for this, the temperature of the dewaxing reactor is gradually increased to meet the target pour point requirements for the product. However, there is a limit that the temperature may be increased before the properties of the product, in particular the oxidation stability, become unacceptable. To this end, the catalytic dewaxing process is typically operated in a temperature-increasing cyclic process with a low Start (SOC) value of typically 232 deg.C to 274 deg.C (450 deg.F to 525 deg.F) and a final end of cycle (EOC) value of typically 354 deg.C to 385 deg.C (670 deg.F to 725 deg.F), after which the catalyst is activated or regenerated for a new cycle. In general, dewaxing catalysts using ZSM-5 as the active component can be activated with hot hydrogen. Other dewaxing catalysts can be decoked with air or oxygen mixed with nitrogen or flue gas. Catalysts containing active components such as ZSM-23 or SAPO-11 (which is less active than ZSM-5 containing catalysts and has a start of cycle (SOC) and end of cycle (EOC) temperature 25-50 ℃ higher than the ZSM-5 containing temperature).

The use of a metal hydrogenation component in a dewaxing catalyst has been described as a highly desirable means for obtaining extended dewaxing cycles and for improving the activation process, even if the dewaxing reaction itself is not a reaction requiring a stoichiometric balance of hydrogen. U.S. p.4,683,052 discloses the use of noble metal components such as Pt or Pd better than the base metals such as Ni used for this purpose. Suitable catalysts for dewaxing and isomerising or hydroisomerisation of feedstocks as described for example 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 may contain 0.1 to 0.6 wt.% Pt. In the present invention, 0.2-1 wt.% Pt is preferred, although Pd is also acceptable.

Chemical reactions between liquid and gaseous phase reactants are difficult to achieve intimate contact between the phases. Such reactions are more complex when the desired reaction is catalytic and requires two mobile phases in contact with the solid catalyst. In operating a conventional co-current multiphase reactor, the gas and liquid tend to flow in different flow paths in some cases. The gas phase may flow in the direction of minimum pressurized pressure, while the liquid phase is passed by gravity in a trickle-like path through and around the catalyst particles. At low liquid to gas ratios, parallel channeling and gas friction can make the flow uneven, thus leaving a portion of the catalyst bed incompletely utilized due to lack of proper wetting. In such cases, the industrial reactor performance may be much worse than would be expected from laboratory studies in which flow conditions in a small pilot plant may be relatively uniform.

In the refining of lubricating oils derived from petroleum by fractionation of crude oil, a series of catalytic reactions can be used for severe hydrotreating, conversion and removal of sulfur and nitrogen impurities, hydrocracking and isomerization of lubricating oil feedstock components in one or more catalytic reactors. Polycyclic aromatic hydrocarbon feedstocks can be selectively hydrocracked by known polycyclic opening techniques. Followed by hydrodewaxing and/or hydrogenation (mild hydrotreating) in contact with different catalysts under various reaction conditions. The combined three-step lubricant refining process disclosed in U.S. patent No. 4,283,271 to Garwood et al is applicable in the present invention.

In a typical heterogeneous hydrodewaxing reactor, the average gas-to-liquid volume ratio in the catalyst zone is from about 1: 4 to 20: 1 at the process operating conditions. The liquid is preferably added to the catalyst bed at a rate of about 10-50% of the void volume. When the liquid raw material and the gas pass through the reactor, the volume of the gas may be reduced due to consumption of the reaction hydrogen. The volume may also be affected by adiabatic heating or expansion of the vapor produced by the dewaxing reaction to form methane, ethane, propane, and butane.

An improved integrated process for hydrocracking and hydrodewaxing a high boiling waxy paraffinic liquid petroleum oil feedstock has now been found. In a fuel hydrocracking unit comprising a downstream vacuum distillation unit, vacuum gas oil, light cycle oil or even deasphalted oil may be hydrocracked. A catalytic dewaxing unit feed containing greater than about 13.5 wt% hydrogen is produced from a fuel oil hydrocracking unit and is then dewaxed, hydrofinished and distilled. At least 50 weight percent of the feedstock is converted to hydrocarbon products having boiling points less than the initial boiling point of the feedstock. The improved method comprises the following steps:

(a) passing a feedstock comprising Vacuum Gas Oil (VGO) or Light Cycle Oil (LCO) or deasphalted oil to a fuel oil hydrocracking system wherein the feedstock is hydrotreated at high pressure, then hydrocracked at high pressure, then fractionated, and then the fractionated bottom residue is vacuum distilled to produce products of desired viscosity and volatility;

(b) hydrodewaxing the fraction from the vacuum distillation unit at an elevated temperature of up to 425 ℃ (797 ° F) in the presence of co-fed hydrogen, in the presence of an acidic, selective, intermediate pore size molecular sieve hydrodewaxing catalyst, at a pressure of at least 10,000kpa (1450psi), in a stage where dewaxing and hydroisomerization can occur simultaneously by uniformly distributed and liquid feedstock contacting, to produce a dewaxed lubricant oil;

(c) in the hydrofining stage, under the condition of aromatic hydrocarbon saturation, the dewaxing lubricating oil is in contact with hydrogen and an effective aromatic hydrocarbon saturation catalyst with a strong metal hydrogenation function, and the dewaxing lubricating oil is hydrofined.

A dewaxed lubricant product (boiling point greater than about 370 ℃) is obtained using a hydrofinishing temperature of 230 ℃ (446 ° F) to 343 ℃ (650 ° F) at an initial cycle (SOC) pressure of at least 10,000kpa (1450 psi). The dewaxed oil has an aromatic content of less than 5% by weight after subsequent distillation and has improved oxidative stability, ultraviolet light stability and thermal stability. The product has a NOACK number of 20 or less, a VI of 115 or more, and a viscosity of 3 to 10cst at 100 ℃.

Preferred hydrodewaxing catalysts include molecular sieves having pores consisting essentially of silicon atoms in place of 10 oxygen atoms, such as aluminosilicate zeolites having the structure of ZSM-5, ZSM-23, or ZSM-35 or ZSM-48. Other non-zeolitic molecular sieves having smaller pore sizes, such as SAPO-11, are also suitable catalysts. In addition to ZSM-5, it is desirable that the catalyst contain 0.1 to 1 weight percent noble metal. Preferred hydrofinishing catalysts to be used thereafter for dewaxing comprise 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. Bimetallic catalysts containing nickel and tungsten metals on porous alumina supports are good examples. The support may be fluorinated.

As previously mentioned, the preferred feeds to a fuel hydrocracking unit are straight run gas oils, such as Light Vacuum Gas Oil (LVGO), Vacuum Gas Oil (VGO) and Heavy Vacuum Gas Oil (HVGO). Typically, VGO and HVGO contain significant amounts of polycyclic aromatic hydrocarbons. After hydrocracking and vacuum distillation, the waxy material to be catalytically dewaxed typically has a VI of at least 125, preferably 130 or greater than 130, and contains about 1 to 15 weight percent aromatics, 10 volume percent boiling points greater than about 315 deg.C (600 deg.F), and no more than 30ppm nitrogen. The hydrogen content is greater than about 14.0% by weight. Its viscosity is greater than 3cS at 100 ℃.

The hydrodewaxed stream is hydrofinished and distilled, then separated to recover a lube oil product boiling above 370 ℃ (698 ° F) and having a Kinematic Viscosity (KV) at 40 ℃ of from 10cSt to 160cSt, or from 3 cSt to 10cSt at 100 ℃. The product lubricating oil has a UV absorption at 325nm of less than 0.001L/g-cm (L stands for liter) and an aromatic content of 5 wt.% or less.

Advantageously, the dewaxing stage and the 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.

Drawings

FIG. 1 is a schematic diagram of a fuel oil hydrocracking apparatus suitable for use in the present invention. The device comprises a hydrotreating tower, a hydrocracking tower, a separator, a vacuum distillation device and a hydrofining tower. The unconverted feed from the fractionator may be recycled to the hydrocracker or may be sent to a vacuum distillation unit where appropriate to cut the feed for the catalytic dewaxing reactor.

FIG. 2 is a simplified flow diagram showing the principal streams representing vertical reactors in series with a fixed catalyst bed.

FIG. 3 is a graph illustrating the relationship between boiling point and viscosity for pure components obtained from Arabian light crude oil and vacuum gas oil.

Figure 4 is a graph showing a comparison of the characteristics of small, medium and large pore zeolites, i.e., molecular sieves.

FIGS. 5-21 are graphs of product performance compared to lubricating oil products for various process parameters of the improved method.

A preferred reactor system is shown in figures 1 and 2.

In the following description, units are in the metric system unless otherwise specified.

I. Raw materials for Integrated Process-overview

The hydrocarbon feedstock of the integrated process of the present invention is a lubricating oil range feedstock having a lube oil initial boiling point and an end point selected to produce a lubricating oil feedstock having suitable lubricating properties. These feedstocks are primarily hydrocarbons having a 10% cut point greater than 345 ℃ (653 ° F) and a viscosity of about 3 to 40cSt at 100 ℃ (as can be determined using fig. 3 and similar relationships). The feedstock is typically produced by vacuum distillation of a fraction of a suitable type of crude oil. Crude oil is typically subjected to atmospheric distillation and atmospheric residues (long boiling residues) are subjected to vacuum distillation to produce the initial unrefined lubricating oil feedstock. Vacuum distillate streams or "neutral" and bright stocks obtained from propane deasphalting of vacuum residua are used to produce products in the viscosity range. Generally for light neutral oils, the viscosity at 100 ℃ may be 4 cSt; for heavy neutral oils, the viscosity at 100 ℃ is about 12 cSt; for bright stock, the viscosity at 100 ℃ is about 40 cSt. In conventional solvent refining lube oil plants, the feedstock is solvent extracted to improve their v.i. and other qualities by selectively removing aromatics with aromatic-selective solvents such as furfural, phenol or N-methyl-pyrrolidone. For the present invention, prior to dewaxing and hydrofinishing, it is necessary to subject the feedstock to hydrocracking in order to obtain the desired product properties.

Unrefined vacuum distillate and Propane Deasphalting (PDA) raffinate are refined by hydrocracking or severe hydrotreating to convert undesirable aromatics and heterocyclic compounds to more desirable naphthenes and paraffins. (see example 3 below). These refined waxy mixtures are low in sulfur and nitrogen and, as mentioned above, can be adjusted in viscosity after distillation.

Fully catalytic lubricant oil production processes using a combination of hydrocracking and catalytic dewaxing are described in U.S. 4,414,097(Chester et al), 4,283,271(Garwood et al), 4,283,272(Garwood et al), 4,383,913(Powell et al), 4,347,121(Mayer et al), 3,684,695(Neel et al) and 3,755,145 (Orkin).

Hydrocracking step

A. Feedstock for hydrotreating/hydrocracking system

The hydrocracking process is operated with a heavy hydrocarbon feedstock such as straight run light vacuum gas oil, heavy vacuum gas oil, and deasphalted raffinate oil, or mixtures thereof, all boiling above about 340 ℃. Although these straight-run oils are preferred, the cracking feedstocks such as light and heavy cracked gas oils and light and heavy FCC gas oils may be added in amounts not exceeding 20% because of their low hydrogen content. (they are high aromatics.) because lubricating oils are generally sold according to their viscosity, and because hydrocracking reduces viscosity, the feedstock to the hydrocracking unit preferably must have a kinematic viscosity at 100 ℃ of 3cS or greater than 3 cS. This means that the preferred boiling point range is above 340 ℃ (see figure 3 below which shows the relationship between 50% boiling point and viscosity for pure components obtained from arabian light crude oil and vacuum gas oil). Feedstocks boiling below 340 c may be included in the feed to the hydrocracking column, but even their lighter products are removed in separator 20. (see FIG. 1). These heavy oils include high molecular weight long chain alkanes and high molecular weight naphthenic and aromatic hydrocarbons. These aromatics will include certain fused ring aromatics, which are detrimental to lubricant stability. In the process, the polycyclic aromatic hydrocarbons and naphthenes are cracked by the acidic catalyst, and the paraffin cracking products and the paraffin components of the starting material are converted into low molecular weight substances after a certain cracking. Hydrogenation of polycyclic aromatic hydrocarbons is catalyzed by the hydrogenation component and promotes cracking of these compounds. Hydrogenation of unsaturated side chains on the original polycyclic single ring cracking residue provides substituted single ring aromatics, which are highly desirable end products. The heavy hydrocarbon oil feedstock will typically contain a significant amount of fractions boiling above 340 c (644F) and having a viscosity above 3cS at 100 c. Its initial boiling point is typically above about 400 ℃ (752 ° F), more typically above about 450 ℃ (842 ° F). The boiling point range can be as wide as 340-. Of course, oils with narrower boiling point ranges, such as those with boiling point ranges of about 400 ℃ and 500 ℃ (about 752 ℃ and 932 ℃ F.), can be processed. Heavy gas oils are typically oils of this type, such as cycle oils and other non-residual materials. Cycle oils from catalytic cracking operations (FCC) and cycle oils from coking operations are particularly unsuitable for use in the production of lubricating oils because they are so highly unsaturated, but they may be blended into the straight oils described above, provided they meet the same boiling points and viscosities required for straight oils. Suitably the hydrocracked feed does not contain more than 20% of the cracked stock. The feed to the hydrocracking column must contain 80% or more of straight-run components.

Using conventional hydrotreating catalysts to remove nitrogen and sulfur and aromatics saturated to naphthenes, an initial hydrocracking step with essentially no change in boiling point range will generally improve catalyst performance and allow the use of lower temperatures, higher space velocities, lower pressures, or a combination of these conditions. Suitable hydrotreating catalysts typically contain a metal hydrogenation component, typically a group VIB or group VIII metal as described above, e.g., cobalt-molybdenum, nickel-molybdenum, supported on a substantially non-acidic porous support such as silica-alumina or alumina. These catalysts are listed in table 1.

TABLE 1

Catalyst suitable for use in an initial hydroprocessing step

Vendor catalyst type

UOP HCH NiMo/A1203

Crossfield 594 NiMo/A1203

Crossfield 504-K NiMo/A1203

Criterion HDN60 NiMo/A1203

Criterion C-411 NiMo/A1203

Criterion C-424 NiMo/A1203

Acreon HR348 NiMo/A1203

Acreon HR360 NiMo/A1203

Akzo KF843 NiMo/A1203

Description of the preferred embodiments

FIG. 1 is a schematic illustration of a preferred reactor system of the fuel oil hydrocracking apparatus of the present invention. Using conventional hydrotreating catalysts to remove nitrogen, sulfur and oxygen, and to saturate olefins and aromatics, an initial hydrocracking step with substantially no change in boiling point range will generally improve hydrocracking catalyst performance and allow the use of higher space velocities, lower pressures, or a combination of these conditions. Suitable hydrotreating catalysts typically contain a metal hydrogenation component, typically a group VIII and group VIB metal, such as cobalt-molybdenum or nickel-molybdenum, on a low acidity porous support such as silica-alumina or alumina. Suitable commercial hydrotreating catalysts suitable for use in the present invention include nickel-molybdenum on alumina catalysts such as UOPHCH, crosfield 594 and Criterion HDN60, and nickel-molybdenum on USY catalysts such as UOPHC-24.

The vertical reactor shell 10 encloses and supports a fixed porous solid bed of hydroprocessing catalyst in overlying series, as depicted at 12A-12E. A feed oil 6 comprising vacuum gas oil, light cycle oil, deasphalted oil or any mixture of these oils is mixed with a hydrogen rich gas stream 8 and introduced into a reactor 10 after heating by suitable heating means 9. The combined feed and hydrogen-rich gas stream passes downwardly through the catalyst bed. In this example, although 5 beds are depicted, there may be more or as few as 2 beds. The liquid is distributed in each bed by any conventional means, such as distributor trays 13A, 13B, 13C, 13D, 13E, which uniformly spray the liquid over the catalyst bed surfaces 12A, 12B, 12C, 12D, 12E. The gas and liquid phases are typically introduced into the reactor at the desired inlet pressure and temperature. The gas and liquid temperatures between the catalyst beds can be adjusted by adding hydrogen-rich quench gases 14A, 14B, 14C, 14D, or either by heat exchange with liquid in an external flow loop, thereby allowing the temperature in any catalyst bed to be controlled individually. Static mixers 15A, 15B, 15C, 15D or other suitable contacting devices may be used to mix the liquid and gas streams between the catalyst zones, including the quench gas, to achieve a uniform temperature.

The effluent stream 16 from the hydrotreating column is passed through a heat exchanger (not shown), a separator 18 and a stripping or fractionation device 20 to separate a recycle gas stream 22 and light conversion products 24. These separations remove by-products NH3 and H2S, which would otherwise poison downstream hydrogenation catalysts. Purge gas stream 28 is typically withdrawn from the recycle gas to remove light hydrocarbon products. Typically, a gas scrubbing apparatus (not shown) is used to remove NH from the recycle gas stream₃And H₂And S. Make-up hydrogen 26 is added to make up the hydrogen consumed in the hydroprocessing reactions and the hydrogen scrubbed in the gaseous and liquid product streams 28, 24 and 30.

The vertical reactor shell 34 encloses and supports a fixed porous solid bed of hydrocracking catalyst stacked in series as depicted at 36A-36E. The following discussion discusses hydrocracking catalysts that may be more than one catalyst, either mixed or in separate beds. The hydrotreated bottoms 30 are mixed with a hydrogen-rich gas 32 and introduced into a hydrocracking reactor 34 after being heated by suitable heating means 33. The combined feed and hydrogen-rich gas stream passes downwardly through the catalyst bed. In this example, although 5 beds are depicted, there may be more or as few as 2 beds. The liquid is distributed in each bed by any conventional means, such as distributor trays 37A, 37B, 37C, 37D, 37E, which uniformly spray the liquid over the catalyst bed surfaces 36A, 36B, 36C, 36D, 36E. The gas and liquid phases are typically introduced into the reactor at the desired inlet pressure and temperature. The gas and liquid temperatures between the catalyst beds can be adjusted by adding hydrogen-rich quench gases 38A, 38B, 38C, 38D, or either by heat exchange with liquid in an external flow loop, thereby allowing the temperature in any catalyst bed to be controlled individually. The liquid and gas streams between the catalyst zones, including the quench gas, may be mixed by static mixer 39A, B, C, D or other suitable contacting device to achieve a uniform temperature.

The effluent stream 38 from the hydrocracking column passes through a heat exchanger (not shown), a separator 40 and a fractionation unit 42 to separate a recycle gas stream 44 and a converted hydrocracked fraction 46. Purge gas stream 50 is typically withdrawn from the recycle gas to remove light hydrocarbon products. Typically, a gas scrubbing apparatus (not shown) is used to remove NH from the recycle gas stream₃And H₂And S. Make-up hydrogen 48 is added to make up the hydrogen consumed in the hydrocracking reaction and the hydrogen scrubbed in the gaseous and liquid product streams 50 and 46. A novel feature of the present invention is that unconverted bottoms 52 go to lube vacuum distillation unit 54. This additional distillation step enables the production of various narrow lube fractions 56, 58, 60, 62, 64 of particular viscosities (e.g., 60N, 100N, 150N) and volatilities. A low volatility lubricating oil stock having a VI of at least 115 can be produced. While 5 lube oil fractions are shown, there may be more than 5 or as few as 2 fractions. These lube fractions are passed from vacuum distillation unit 54 to a catalytic dewaxing process as shown in figure 2.

In some cases, it is desirable to recycle some unconverted hydrocracking bottoms 52, or unused fractions of this stream, from the vacuum distillation units 56, 58, 60, 62, 64 back to the hydrocracking column 34. This is shown as stream 66. In addition, it is desirable to pass these unconverted hydrocracking bottoms streams to a second hydrocracking column, either to an FCC unit or to fuel.

Tables 3 and 4 (see example 1 below) illustrate how a lube oil product can be obtained from a hydrocracker by adding a lube oil vacuum distillation unit as described in the present invention.

II.C hydrocracking catalyst

The catalyst used in the hydrocracking process of the present invention may be a conventional hydrocracking catalyst using an acidic large pore size zeolite belonging to a porous support material having a function of adding metal hydrogenation/dehydrogenation. Specific commercial hydrocracking catalysts that may be used include UOP HC-22 and UOPHC-24. They are NiMo catalysts supported on USY supports. ICR209, Chevron catalyst containing Pd on USY support, can also be used. Table 2 lists suitable hydrocracking catalysts. In hydrocracking catalysts, the acidic function is provided by a large pore amorphous material such as alumina, silica-alumina or silica, or by a large pore crystalline material, preferably a large pore aluminosilicate zeolite such as zeolite X, Y, ZSM-3, ZSM-18, ZSM-20 or zeolite beta. Various cationic and other forms of zeolite may be used, preferably in a more stable form, to resist degradation and consequent loss of acidic function under the influence of hydrothermal conditions encountered in the hydrocracking process. Thus, forms of enhanced stability such as rare earth exchanged large pore zeolites such as REX and REY, and also known as ultrastable zeolite Y (usy) and high silica zeolites such as dealuminated Y or dealuminated mordenite are preferred.

Zeolite ZSM-3 is disclosed in U.S. 3,415,736, zeolite ZSM-18 is disclosed in U.S. 3,950,496, zeolite ZSM-20 is disclosed in U.S. 3,972,983, and the description of these zeolites, their properties and preparation are incorporated by reference. Zeolite USY is disclosed in U.S. p.3,293,192 and RE-USY is disclosed in U.S. p.4,415,438. Hydrocracking catalysts containing zeolite beta are disclosed in EP94827 and u.s.p.4,820,402, to which reference is made for a description of these catalysts.

Preferred catalysts include a binder such as silica, silica/alumina or other metal oxide such as magnesia, titania, typically in a binder to zeolite ratio of from 10: 90 to 90: 10, more typically from about 30: 70 to 70: 30 (by weight).

TABLE 2

Catalyst suitable for hydrocracking step before dewaxing

Vendor catalyst type

UOP HC-24 NiMo/USY

Chevron ICR209 Pd/USY

Acreon HYC632 NiMo/zeolite

Acreon HYC642 NiMo/zeolite

Acreon HYC652 NiMo/zeolite

Akzo Kc-2000 NiMo/zeolite

Akzo Kc-2100 Pd/zeolite

Criterion Z-703 NiW/zeolite

Criterion Z-753 NiW/zeolite

Criterion Z-763 NiW/zeolite

II.D hydrocracking process conditions

The hydrocracking process is carried out under conditions similar to those used for conventional hydrocracking. Process capable of being used convenientlyTemperatures of about 260-. The temperature generally used is 315-. The total pressure is typically 1200-3000psi (8274-20685kpa), and higher pressures in the range above 1800psi (12600kpa) will generally be preferred. The process is operated in the presence of hydrogen, typically at a hydrogen partial pressure of at least 1200psig (8274 kpa). The ratio of hydrogen to hydrocarbon feedstock (hydrogen recycle ratio) is typically 2000-5000 SCF/BbI. (about 18-980n.l^-1). The space velocity of the feed is generally in the range of 0.1 to 10LHSV (hr)^-1) Preferably 0.5 to 5 LHSV. At low conversion, the normal paraffins in the feedstock will be isomerized to isoparaffins, but at higher conversion under harsher conditions, the isoparaffins will be converted to lighter materials.

The conversion may be carried out by contacting the feedstock with a fixed, stable catalyst bed. A simple configuration is a trickle bed operation in which the feed is trickled through a static fixed bed (this is illustrated in figure 1). According to such a configuration, it is desirable to start the reaction with fresh catalyst at moderate temperature, of course, the temperature is raised as the catalyst ages to maintain catalytic activity. For example, at elevated temperatures, the hydrocracking catalyst may be regenerated by contact with hydrogen, or by combustion in the presence of a mixture of air, nitrogen and flue gas.

Catalytic dewaxing process (or hydrodewaxing or hydroisomerization process)

FIG. 2 illustrates a general embodiment of the present invention, but is not intended to limit the present invention. The vertical reactor shell 10 encloses and supports a fixed porous solid bed of dewaxing catalyst stacked in series as depicted at 12A-12C. The raw oil 6 comprising a waxy liquid oil is mixed with a hydrogen-rich gas 8 and introduced into a reactor 10 after being heated by suitable heating means 9. The combined feed and hydrogen-rich gas stream passes downwardly through the catalyst bed. In this example, although 3 beds are depicted, there may be more or as few as 2 beds. The liquid is distributed by any conventional means, such as distributor trays 13A, 13B, 13C, which uniformly spray the liquid over the catalyst bed surfaces 12A, 12B, 12C. The gas and liquid phases are typically introduced into the reactor at the desired inlet pressure and temperature. The gas and liquid temperatures between the catalyst beds can be adjusted by adding hydrogen-rich quench gas 14A, 14B or optionally by heat exchange with liquid in an external flow loop, thereby allowing the temperature in either catalyst bed to be controlled separately. Static mixers 15A, 15B or other suitable contacting means may be used to mix the liquid and gas streams, including the quench gas, between the catalyst zones to achieve a uniform temperature.

The effluent stream 24 from the hydrodewaxing reactor is heated or cooled as needed by a heat exchanger or furnace 25 and is passed in series directly to the hydrofinishing reactor 30. The vertical reactor shell 30 encloses and supports a fixed porous solid bed of hydrofinishing catalyst stacked in series, as depicted at 32A-32C. Liquid and gas volumes flow downward through the catalyst bed. In this example, although 3 beds are depicted, there may be more or as few as 2 beds. The liquid is distributed by any conventional means, such as distributor trays 33A, 33B, 33C, which uniformly spray the liquid over the catalyst bed surfaces 32A, 32B, 32C. The gas and liquid phases are typically introduced into the reactor at the desired inlet pressure and temperature. The gas and liquid temperatures between the catalyst beds can be adjusted by adding hydrogen-rich quench gas 34A, 34B or optionally by heat exchange with liquid in an external flow loop, thereby allowing the temperature in either catalyst bed to be controlled separately. The liquid and gas streams between the catalyst zones, including the quench gas, can be mixed by static mixer 35A, B or other suitable contacting device to achieve a uniform temperature.

Hydrofinishing column effluent stream 36 passes through a heat exchanger (not shown), separator 40 and fractionation unit 42 to separate a recycle gas stream 44, a converted fraction 46 and a finished lubricant base stock 48. Purge gas stream 50Typically, it is withdrawn from the recycle gas to remove light hydrocarbon products. Typically, a gas scrubbing apparatus (not shown) is used to remove NH from the recycle gas stream₃And H₂And S. Make-up hydrogen 52 is added to make up the hydrogen consumed in the hydrodewaxing and hydrotreating reactions and the hydrogen scrubbed in the gaseous and liquid product streams 50 and 46.

Continuous multistage reactor systems have been described for contacting the vapor and liquid phases with porous catalyst beds in series, however, other reactor configurations with 2-5 beds may be desirable. The catalyst composition in all beds in each reactor may be the same, however, it is also within the concept of the invention to have different catalysts and reaction conditions in separate catalyst beds. The design and operation can be modified for specific processing requirements in accordance with normal chemical engineering practices.

The present techniques are applicable to a variety of catalytic dewaxing operations, particularly for treating heavy oils in the lubricant oil range with hydrogen-containing gas at elevated temperatures. Industrial processes using hydrogen, particularly petroleum refining, use recycled impure gases containing 10-30% (mole) or more impurities, usually light hydrocarbons and nitrogen. Such gases are available and useful herein, particularly for high temperature hydrodewaxing at elevated pressures.

Advantageously, the catalyst bed has a void volume fraction greater than 0.25. With loosely packed multilobal objects or cylindrical extrudates, pellets or tablets, providing a suitable liquid flow rate composition for uniformly wetted catalyst, void fractions of 0.3 to 0.5 can be obtained to promote mass transfer and catalysis. The height of the catalyst bed may be 2-6 meters.

In this process, a waxy lube oil feedstock, typically a 321 ℃ + (about 610F +) feedstock, is added to a medium pore size molecular sieve catalyst having dewaxing and/or isomerization or hydroisomerization functionality in the presence of hydrogen to produce a dewaxed lube oil boiling point range product of low pour point (ASTM D-97 or equivalent such as Autopour). To pairIn a typical waxy feed, the hydrogen feed rate at the top of the dewaxing reactor was about 267-534 n.l.l..^-1(1500-3000 SCF/BBL). To improve the stability of the dewaxed lube oil boiling point range feed in the dewaxed stream, a hydrofinishing step is typically performed.

Hydrodewaxing process conditions

Generally, when ZSM-5 is the active component of the catalyst, the catalytic dewaxing process step is operated at elevated temperature conditions, typically about 205-. When other less active catalysts are used, the temperature may be 25-50 ℃ higher than that of ZSM-5.

As the target pour point of the product is lowered, the severity of the dewaxing process is increased by increasing the reactor temperature so as to greatly increase the conversion of normal paraffins, and so the lube yield generally decreases as the product pour point decreases as successively greater amounts of normal paraffins (waxes) in the feed are converted by selective cracking over the dewaxing catalyst to produce lighter products boiling outside the lube boiling range. As the pour point decreases, the v.i. of the product will also decrease as high v.i. normal paraffins and slightly branched isoparaffins are gradually converted.

In addition, the dewaxing temperature is increased during each dewaxing cycle to compensate for the reduced catalyst activity due to catalyst aging. When the temperature reaches about 400 c (about 750F), but preferably about 385 c (725F), the dewaxing cycle is typically discontinued due to the adverse effects of viscosity and product stability at higher temperatures. These temperatures can be as high as 25-50 ℃ when ZSM-5 is the active catalyst component of the less active catalyst.

The hydrogen facilitates extended catalyst life by reducing the rate of coke deposition on the dewaxing catalyst. ("Coke" is a highly carbonaceous hydrocarbon that tends to accumulate on the catalyst during the dewaxing process) and thus is typically at a hydrogen partial pressure of about 2758-20685kpa (400-3000psia), preferably about 9653-17238kp in the presence of hydrogenThe process is carried out at a (1400 ℃ F. 2500psi), more preferably 1600 ℃ F. 2200psi (11032 ℃ F. 15169kPa), although higher pressures may also be used. The hydrogen circulation rate is typically 180-^-1(1000-4000 SCF/bbl, typically 2000-3000 SCF/bbl), additional hydrogen may be added at the quench point. Space velocities vary depending on the feedstock and severity of the pour point desired to be achieved, but are typically in the range of 0.25 to 5 LHSV (hr) for all catalysts^-1) Preferably 0.5 to 3 LHSV.

Hydrodewaxing catalyst

Recent developments in zeolite technology have provided a group of defined mesoporous siliceous materials with similar pore structures. Preferred hydrodewaxing catalysts comprise porous acidic molecular sieves having pores consisting of 10 oxygen atoms replaced primarily by silicon atoms, such as aluminosilicate zeolites. Of these medium pore zeolites, the most important are ZSM-5, ZSM-23, ZSM-35 and ZSM-48, which are typically synthesized in the zeolite framework by adding tetrahedrally coordinated metals such as Al, Ga or Fe with Bronsted acidic active sites. For selective acid catalysis, mesoporous molecular sieves having a pore size of about 3.9 to 6.3  are advantageous; the advantages of the mesoporous structure can be exploited by using a high silicon material or a crystalline molecular sieve with one or more tetrahedral materials of different acidity. These selective substances have at least one pore channel formed by a 10-membered ring containing 10 oxygen atoms substituted with silicon and/or metal atoms.

Catalysts that have been proposed for selective catalytic dewaxing processes typically contain molecular sieves having a molecular sieve which is accessible to either straight chain waxy normal paraffins alone or paraffins with only slight branching, but excludes more highly branched materials and cyclic aliphatic hydrocarbons. Representative medium pore molecular sieves are ZSM-5(U.S. P.3,702,886), ZSM-11(U.S. P.3,709,979), ZSM-22, ZSM-23(U.S. P.4,076,842), ZSM-35(U.S. P.4,016,245), ZSM-48(U.S. P.4,375,573), ZSM-57 and MCM-22(U.S. P.4,954,325), and SAPO-11(U.S. P.4,859,311). ZSM-24 is a synthetic ferrierite. (see FIG. 4). The disclosures of these patents are incorporated herein by reference.

Molecular sieves offer advantages over non-crystalline catalysts in catalytic dewaxing. Molecular sieves are broadly classified into small, medium and large pore materials, as shown in FIG. 4. The pore size is fixed by a ring of oxygen atoms. The small pore zeolites have 8-membered ring openings, the medium pore zeolites have a 10-membered system, and the large pore zeolites have a 12-membered system. The pore structure of the catalyst may also affect catalytic dewaxing performance regardless of its type of mono-or bi-directional channels and its channel intersections. Severely restricted small pore zeolites are ineffective in lubricating oil dewaxing because they allow only small normal paraffins to enter the channels. In contrast, large pore zeolites allow for the non-selective cracking of certain desirable lubricating oil components, resulting in lower yields than those obtained with medium pore zeolites.

HZSM-5 is one of many medium pore zeolites that is 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 the ZSM-5 provides reactant shape selectivity, reduces the tendency for coking and eliminates the balance of poisoning of the bulk nitrogen-containing catalyst. In the present invention, HZSM-5, Pt/ZSM-23, Pd/ZSM-23, Pt/ZSM-48 and Pt/SAPO-11 with appropriately adjusted physicochemical properties are preferred because their channel system and pore size enable efficient dewaxing of the fuel hydrocracking bottoms.

Suitable molecular sieves having a coordination metal oxide to silica molar ratio of from 20: 1 to 200: 1 or more can be used, for example for HZSM-5 it is advantageous to use a conventional aluminosilicate ZSM-5 having a silica to alumina molar ratio of from about 25: 1 to 70: 1, although molar ratios above 70: 1 can also be used. A typical zeolite catalyst component having Bronsted acid sites may consist essentially of a crystalline aluminosilicate having the zeolite structure of ZSM-5 with 5 to 95% by weight of silica, clay and/or alumina binder. It is to be understood that other medium pore acidic molecular sieves, such as salicylates, Silicoaluminophosphate (SAPO) materials, can be used as catalysts, particularly medium pore SAPO-11.

U.S. 4,908,120(Bowes et al) discloses a catalytic process useful for feedstocks having high paraffin content or high nitrogen content. The process uses a binderless zeolite dewaxing catalyst, preferably ZSM-5.

Mesoporous zeolites are particularly useful in this process because of their good regeneration performance, long life and stability under extreme operating conditions. Typically the zeolite crystals have a crystal size of from about 0.01 to over 2 microns or more, with 0.02 to 1 micron being preferred. Although ZSM-5 in its metal-free form (. gtoreq.40. alpha.) can be used for selective cracking, in the case of the other medium-pore acidic metallosilicates mentioned above it is necessary that they are upgraded with 0.1 to 1.0% by weight of noble metal in order to be used as hydroisomerization dewaxing catalyst.

ZSM-5 is the best intermediate pore size molecular sieve, i.e., a mesoporous acidic molecular sieve, which is free of noble metals and is used for industrial selective dewaxing in practice. In order to reduce the rate of catalyst aging to a practical level, noble metals and other mesoporous molecular sieves are required. However, the addition of noble metals to ZSM-5 renders it hydroisomerizing active, which increases the yield of dewaxed lubricant oil. It has been found that when noble metals are added to ZSM-23, ZSM-35, SAPO-11 and ZSM-5, the typical product yields and VI for ZSM-23, ZSM-35 and SAPO-11 are higher than for ZSM-5. The choice of the catalyst to be used becomes an economic problem.

The catalyst size can vary widely within the concept of the invention, depending on the process conditions and reactor configuration. Finished catalysts having an average maximum dimension of 1 to 5mm are preferred.

Catalytic dewaxing conditions

In most of the catalytic dewaxing examples herein, the catalyst used was 65 wt% ZSM-5 having an acid cracking (. alpha.) value of 105 and formed as 1.6mm diameter extrudates; however, alpha values of about 1-300 may be used. Reactor configuration is a particularly important consideration when designing continuously operating systems. In its simplest form, a vertical pressure vessel is provided containing a series of (at least 2) overlapping catalyst beds of uniform cross-section. Vertical reactors having a total catalyst bed length to width ratio (L/D direction) of from about 1: 1 to about 20: 1 are generally preferred. The beds in overlapping series can be placed in the same reactor shell, however, similar results can be obtained using separate side-by-side reactor vessels. Reactors of uniform cross-section are preferred, however, non-uniform configurations may be used, provided that the bed flow rate and corresponding circulation rate are appropriately adjusted.

The invention is particularly useful in the catalytic hydrodewaxing of heavy petroleum gas oil lubricant feedstocks having boiling points above 315 c (599F). Using packed catalyst bed with extruded bar of medium pore molecular sieve at liquid hourly space velocity not more than 5hr^-1Preferably about 0.5^-3hr^-1The catalytic dewaxing treatment can be completed under the conditions of (1). The hydrocarbon feed to the catalytic dewaxing column has a viscosity of from 3 to 12cSt at 100 ℃. Advantageously, the liquid flow rate is maintained at 2441-²/hr (500-²-hr, preferably 1000-²-hr). The reactant gas was added at a uniform volumetric rate per barrel of oil.

Hydrofining after catalytic dewaxing

To improve the quality of the dewaxed lubricant product, the catalytic dewaxing is followed by a hydrofinishing step (see fig. 2) to saturate the lubricant range olefins and remove heteroatoms, color bodies, which saturate the residual aromatics if the hydrofinishing pressure is high enough. Hydrofinishing after dewaxing is usually carried out in series with the dewaxing step. Generally, at the beginning of the cycle, hydrofinishing will be carried out at a temperature of about 230-. The total pressure is typically 9653-. The liquid hourly space velocity in the hydroprocessing reactor is typically in the range of from 0.1 to 5 LHSV (hr)^-1) Preferably 0.5-3hr^-1。

Processes using continuous lube catalytic dewaxing-hydrofinishing are disclosed in U.S. patent nos. 4,181,598, 4,137,148 and 3,894,938. A process using a reactor with an additional dewaxing-hydrofinishing bed is disclosed in U.S. patent No. 4,597,854. Reference is made to these patent documents for a detailed description of these processes. The hydrofinishing step following the dewaxing step improves the quality of the product without significantly affecting its pour point. The metal function of the hydrofinishing catalyst is effective in saturating the aromatic hydrocarbon components. Thus, a Hydrofinishing (HDF) catalyst having a strong hydrodesulfurization/hydrogenation function that can be provided by a noble metal, nickel-tungsten, or nickel-molybdenum, would be more effective than a catalyst containing a weaker metal function, such as molybdenum alone. A preferred hydrofinishing catalyst for aromatics saturation will comprise at least one metal having a relatively strong hydrogenation function supported on a porous support. Because the hydrogenation reaction required requires little acidic functionality and because no conversion to lower boiling products is desired at this stage, the carrier of the hydrofinishing catalyst is less acidic. Typical support materials include amorphous or crystalline oxide materials such as alumina, silica and low acidity silica-alumina. For non-noble metal catalysts, the metal content of the catalyst is typically about 20 wt% higher. The noble metal is typically present in an amount of no greater than 1.0 weight percent. Hydrofinishing catalysts of this type are readily available from catalyst suppliers. The nickel-tungsten catalyst may be fluorinated.

Control of the reaction parameters of the hydrofinishing step provides a useful means of altering product stability. Using a mixture of metals from groups VIIIA and VIA of the periodic Table (IUPAC periodic Table), such as nickel/tungsten, the temperature of the hydrofinishing catalyst is about 230 ℃ and 300 ℃ (446 ℃ and 572 ℃ F.) to minimize monocyclic and polycyclic aromatics. This will also provide products with good oxidative stability, UV light stability and thermal stability. The lower space velocity, which greatly affects aromatics saturation, controls aromatics saturation, and the space velocity of the hydrofinishing reactor also offers a potential. The hydrofinished product preferably contains no more than 10% by weight aromatics.

Examples

The following examples are illustrative only and are not to be considered as limiting.

Example 1

Table 3 gives analytical data for atmospheric bottoms from a commercial two-stage hydrocracking unit. Such hydrocracking units have one hydrotreating reactor and one hydrocracking reactor, but do not have a vacuum distillation unit as in the hydrocracking unit of the present invention. The product was a fraction of about 330 ℃ 538 ℃ (625 ℃ 1000 ° F) with low heteroatom and aromatic content, especially nitrogen content. The hydrocracking catalyst used was fresh. The full range analytical data for the recovered drum atmospheric bottoms is listed in the column "Total bottoms". The bottoms were split into 5 fractions of equal volume and analyzed for major properties, and these analytical data are also shown in table 3.

After hydrodewaxing, hydrofinishing and distillation processes, including catalytic dewaxing, the final product must have the following properties:

viscosity index is not less than 115

NOACK＞6≤20

Viscosity (at 100 ℃ C. 4-5cSt)

Chroma is more than or equal to 20

Pour point less than or equal to-4 ℃ (25 DEG F)

Aromatic hydrocarbons less than or equal to 5 wt.%

Stable color and luster under sunlight

In order to obtain a final product with these properties, it is desirable to start with a feedstock with as high VI as possible and as low NOACK as possible (or as high flash point as possible). Hydrodewaxing processes lower pour point. In Table 3, the higher the volatility of the fraction, the lower the pour point, while the heavier, less volatile fraction had a higher VI. The most volatile fraction distilled off at 0-20% has a low viscosity (2.77 cSt at 100 ℃) and a VI below 115, so that it is not suitable.

In order to obtain the properties of the products described above, it is necessary to obtain raw materials having properties in an acceptable range. In the present invention, a reduced pressure distillation step is used. As shown in table 4, even the lightest, most volatile hydrocracked and vacuum distilled bottoms fractions are suitable, having a VI of more than 115 and a viscosity at 100 ℃ of more than 4 cSt.

TABLE 3 distillation of atmospheric residue in an industrial hydrocracking column to 5 equal volumes of distillate

Whole bottoms resid 0-20-40-60-80-100% distillation yield wt.% 19.419.018.719.923.1 vol% 19.519.118.619.822.9 specific gravity, ° API 38.439.439.537.737.837.2 Sp. Gr.60F/60F 0.83290.82800.82750.83630.83580.8388 pour point, ° C. (° F) 38(100) 16(60) 24(75) 32(90) 38(100) 49(120) ASTM color < 0.5COC flash point, ° F216.11 (421) KV @40 ℃, cSt 19.3310.2313.7217.34- - -KV @100 ℃, cSt 4.3702.7703.4564.1444.9727.365 KV @300 ℃, cSt 2.2851.5211.8242.0622.4603.278 @38 ℃, (100F) 101627692113216 VI 141114132147- - - -

TABLE 4

Vacuum distillation tower bottom for vacuum gas oil hydrocracking oil

Distillation of oil fractions of equal volume

0-20% of reduced pressure distillation tower, 20-40% of reduced pressure distillation tower, 40-60% of reduced pressure distillation tower, 60-80% of reduced pressure distillation tower and 80-100% of reduced pressure distillation tower

Bottoms distillation yield wt.% 19.118.718.718.924.5 vol% 19.218.718.718.724.1 specific gravity, ° API 35.635.935.534.934.132.9 sp. gr.60 ° F/60 ° F0.84680.84530.84730.85040.85450.8607 pour point, ° c (° F) 43(110) 27(80) 29(85) 38(100) ASTM color 3.5COC flash point, ° F260 ℃ (500) KV @40 ℃, cSt-23.76- — -KV @100 ℃, cSt 7.1154.8985.5056.3547.48010.42 KV @300 ℃, cSt 3.3082.3732.6262.9333.3594.308 SUS @38 ℃, (100 ° F) 182123137170212364 VI-133- -

Example 2

FIG. 5 illustrates the relationship between viscosity index and hydrogen content for a lube oil having a pour point of-7 deg.C, wherein the oil has been refined either by solvent refining or by hydrocracking. Each of the various waxy feeds compared was solvent dewaxed to a pour point of-7 c. The VI viscosity index improves as the weight percent of hydrogen present in the lubricant base oil increases. The hydrocracked feedstock was slightly improved over the solvent refined feedstock in VI. The open circles represent lube oil stocks that have been hydrocracked, distilled, and solvent dewaxed from lube oils without further treatment. The circles with cross-hatching represent the lube oil stocks refined by fuel hydrocracking, distillation and solvent dewaxing. The squares represent solvent refined and solvent dewaxed lubricant stocks. The upright triangles represent vacuum distillates obtained from paraffin-based crude oil. The inverted triangle represents the vacuum distillate from naphthenic base crude.

It is clear that hydrocracking of vacuum gas oil will provide a higher VI lube stock than lube oil hydrocracking or solvent refined lube stock, since vacuum gas oil hydrocracking is more severe than lube oil hydrocracking. In the present invention, the dewaxed lubricant stock must have a VI of at least 115. As can be seen in FIG. 5, in order to obtain a VI of 115, the dewaxed oil product must have a hydrogen content of at least about 14.1 weight percent. Because dewaxing reduces the hydrogen content, the hydrogen content of the waxy oil must be about 0.2 to 0.5 weight percent higher than the hydrogen content of the dewaxed oil. Thus, a key feature of the invention is that the hydrocracking unit provides a vacuum distillation product having at least 14.3 wt.% hydrogen. In fig. 5, PONA analysis of these hydrocracked lube stocks illustrates that they have a large variation in composition, some with a high paraffin content, some with a high naphthene content, and others in between. Thus, infinite variation in composition at any value of VI is possible, which variation can be described by a range of hydrogen contents for any value of VI. The hydrogen content of 150 isoalkanes with carbon atoms of C17-C55 is 15.1-14.6 percent respectively. For alkylcyclohexane, which is invariant, at 14.37%; for alkylbenzenes, it is from 12.4 to 13.69%. Thus, it follows that the dewaxed oil product must be substantial in the high hydrogen content isoparaffins and alkylcyclohexanes. A gas oil hydrocracking unit, i.e. a hydrocracking unit operating with more than 40% conversion to light products at 345 c, can produce products at 345 c + with a suitable hydrogen content to provide a dewaxed oil with a viscosity index of 115.

Example 3

Fig. 6 (parts a, b and c) is an illustration of lube hydrocracking and gas oil hydrocracking for heavy vacuum gas oil obtained from Statfjord crude. The heavy vacuum gas oil was hydrocracked in a pilot plant at various conversions, distilling the hydrocracked product and removing all 345 ℃ (653 ° F) material. The 345 c + waxy oil was then solvent dewaxed to a pour point of-18 c (0F) and the viscosity and VI were measured. The range of conversion from 10 to about 30% is referred to as lube hydrocracking range, and the range of conversion from 30% and higher is referred to as gas oil hydrocracking range. It is clear that about 35% conversion of hydrocracking is required to obtain a dewaxed product having a VI of 115. The degree of conversion required depends on the viscosity of the feed to the hydrocracking unit. Figure 6 also illustrates how the viscosity is reduced when hydrocracking is initiated. This is why gas oil hydrocracking units are limited to producing products in the low viscosity range, for example 60-250 SSU at 100 ° F or 3-6cSt at 100 ℃). FIG. 6 also shows that the yield of 345℃ + in the gas oil hydrocracking unit is low.

The data in examples 4-12 were obtained from two reactor processes, catalytic dewaxing and hydrotreating. (see example 5 for a detailed discussion). The first reactor contains a proprietary hydrodewaxing catalyst HZSM-5.

The same hydrodewaxing catalyst is used for both the high and low pressure operations. In the second reactor, an industrial hydrofinishing catalyst was used. At low pressure (2.86X 10)³-4.2×10³kpa) and only hydrofinishing catalysts are designed for olefin saturation. However, for good oxidation stabilitySex and UV light stability, a certain degree of aromatic saturation is required. Used at high pressure (1.73X 10)⁴kpa) for aromatics saturation. To provide a comparison, at 1.53X 10⁴kpa evaluates the hydrofinishing catalyst used at low pressure.

Examples 4

The NOACK volatility test was performed on neat (unblended) base oils using a NOACK evaporation tester according to the CECL-40-T-87 "loss of evaporation of lubricating oil" test (see FIGS. 7 and 8). Collectively, the method measures the evaporative loss weight% of the sample maintained at 250 ℃ (482 ° F) for a period of 60 minutes under a fixed air stream.

Figure 7 shows the NOACK volatility of base stocks produced by high and low pressure catalytic dewaxing followed by hydrofinishing. In general, NOACK volatility is related to the percentage distilled off at 399 deg.C (750 deg.F.) in a D2887 simulated distillation (see FIG. 7 and Table 5). There was also a good relationship between NOACK and the 10% point for these products (see figure 8).

The flash point and NOACK behave in the opposite way when 5% or 10% boiling point, respectively, is involved. FIG. 9 provides the relationship between flash point and 5% boiling point.

TABLE 5

Comparison of products obtained using high pressure HDF with Standard HDF

HDF catalyst type aromatic saturation catalyst Standard olefin saturation hydrofinishing catalyst Condition pressure, KPa (psig) 1.73X 10⁴KPa 1.73×10⁴KPa 1.73×10⁴KPa 1.73×10⁴KPa 2.86×10³KPa 2.86×10³KPa 1.86×10³Pa 1.53×10⁴KPa(100％H₂) (2500) (2500) (2500) (2500) (400) (400) (2500) (2200) HDT temperature, ° F329 (625) 302(575) 274(525) 232(450) 241(465) 260(500) 288(550) 260(500) NOACK volatility of undoped (unadditized) oil, wt% 23.818.817.920.318.617.719.518.0 SAB color 282829291.01.5-169 light stability to haze/precipitated 42+ 42+ 42+ 42+ < 4 days at 399 ℃ (750 ° F) 26.321.020.820.722.321.624.624.6% simulated distilled% UV absorbance, L/g-cm226nm 0.01130.004150.002550.02810.9230.7660.7260.324254 nm 0.0007400.0003790.0002190.001190.1330.1220.1290.0223275 nm 0.001200.0004610.0002830.002500.1610.1420.1580.0372325 nm 0.0004600.000063 < 0.000100 < 0.0001000.02870.03410.04670.00336400 nm 0.0000060.000003580500565565472510640560 minutes reduction of 25psi for < 0.000100 < 0.0001000.002750.003860.00513 < 0.000100 oil + 0.3% Irqanox ML820 RBOT Oxidation test

Example 5

With a hydrocracked low aromatics and low nitrogen feed, two catalyst systems (high pressure catalytic dewaxing + Arosat HDF catalyst (fluorinated NiW/Al)₂O₃) And low pressure catalytic dewaxing + HDF catalyst (Mo/Al)₂O₃) Can easily meet pour point requirements and achieve similar lube yields and viscosities. The general characteristics are summarized below.

At 1.73X 10⁴kpa (with 2.86 x 10)³kpa comparison) [ (2500psig vs 400psig)]In operation, dewaxing catalyst aging is reduced from 2.3 to 0.2F/day, potential cycle length is greatly extended, and plant stream factor is improved. The pour point decreases by a factor of two in response to changes in catalytic dewaxing temperature at high pressure, which promotes the production of very low pour point base stocks if desired (see fig. 10).

Lube oil yields and VI are relatively pressure sensitive (see FIG. 11) and yields of 67-72 wt% for producing 121VI, 116SUS base stocks with a pour point of-15 deg.C (versus 82 wt% for 129 VI, 107 SUS base stocks produced by solvent dewaxing on a dry wax basis).

Standard low pressure catalytic dewaxing allows little adjustment of the total aromatics content as determined by UV absorbance at 226nm (figure 12). At 1.73X 10⁴kpa (2500psig) use of an aromatic saturation catalyst at a HDF temperature of 274 ℃ (525 ° F) allows the reduction of the aromatic content, as determined by UV absorbance, to an equilibrium value.

The low pressure procedure was carried out in a pilot plant with two reactors with in-line nitrogen stripping capability. Reactor 1 was charged with 225cc of dewaxing catalyst HZSM-5 and reactor 2 was charged with225cc hydrofining catalyst (Mo/Al)₂O₃) Designed for olefin saturation and low levels of desulfurization (critical to maintaining oxidation stability of conventional finished lubricant base stocks). Both catalysts were 1/16 "cylindrical extrudates and were produced commercially.

Using pure hydrogen gas 2.9X 10³400psig total pressure of kpa (415psi hydrogen partial pressure) with 1.73X 10⁴Low pressure operation was carried out with 1 LHSV (per reactor) of kpa (2500 scf/B) hydrogen recycle. To find (blacket) at the optimum processing severity for the production of UV light stable base stocks, three HDF temperatures (241 deg.C, 274 deg.C and 288 deg.C) were investigated at the specified pour point (-15 deg.C).

High pressure catalytic dewaxing was carried out in a two reactor pilot plant. Reactor 1 was charged with 262cc of dewaxing catalyst, which was the same dewaxing catalyst used at standard pressure operation. Reactor 2 was charged with 62cc of a commercial hydrofinishing catalyst (Arosat) having excellent aromatics saturation capacity. Which is a commercially available 1/16 "four-lobed extrusion.

At 1.73X 10⁴kpa (2500psig total pressure using pure hydrogen 1.74 x 10⁴kpa (hydrogen partial pressure)) and 1 LHSV (per reactor) with 445n.l.l (2500 scf/B hydrogen recycle). For the production of UV light stable base stocks, four hydrofinishing temperatures (329 deg.C, 302 deg.C, 274 deg.C and 232 deg.C) were investigated at the specified pour point (-15 deg.C) in order to find out the severity at which the treatment is optimal. The data in fig. 12 clearly show that a hydrofinishing reactor after the dewaxing reactor requires a very good aromatics saturation catalyst.

Example 6

Stability to sunlight

Introduction to the method

In this test, a neat (unadditized) base stock placed in a bottle was exposed to natural sunlight and was periodically observed for haze, precipitation, and color change. All samples were run simultaneously at the same location.

Results

The light stability of the high pressure catalytically dewaxed and hydrotreated base stocks was excellent when the aromatic saturation catalyst was used, with no precipitation after 42 days (see fig. 13). The products obtained by low-pressure catalytic dewaxing and hydrofinishing and also by solvent dewaxing have a poor photostability and deteriorate in 2-3 days. This indicates that the photolabile is not the result of the catalytic dewaxing step, but rather the result of the unstable components in the hydrocracker bottoms. Such instability is generally associated with 3+ cyclic aromatics, which can be detected by UV absorbance at 325 nm. Upon absorption of light, these compounds oxidize to produce free radical chain initiators, which then react with other hydrocarbons to produce carboxylic acids. In feedstocks such as these low aromatics, the solubility of these oxygenates is very low and they precipitate out. The high pressure catalytically dewaxed and hydrofinished base stocks had a 325nm UV absorbance that was several orders of magnitude lower than the other samples (see figure 12 and table 5). Notably, standard catalytic dewaxing hydrotreating catalysts, for the removal of these unstable compounds, were even at 1.53X 10⁴kpa (2200psig) is also not well suited. The results of photostability of fig. 13 are correlated with the UV results of fig. 14.

Example 7

The RBOT test for oxidation stability (rotary oxygen bomb oxidation of turbine oil) was performed according to ASTM method D2272. It was made with base oil +0.3 wt% Irganox ML820, Irganox ML820 being a commercially available turbine oil additive package. In this test, the sample is placed in a pressure bomb together with water and a copper catalyst ring. The bomb was pressurized to 620kpa (90psi) with oxygen, placed in a bath at 150 ℃ (302 ° F), and rotated on an inclined axis. Record the number of minutes required for the pressure to drop to 172kpa (25 psi); thus, higher results indicate good oxidative stability (see table 5 and fig. 15).

Results

The RBOT performance of the high pressure catalytic dewaxed and low pressure catalytic dewaxed base stocks were similar and very good (see fig. 15). Solvent dewaxed oils from the same industrial feed are also good, but the average value is somewhat low. The solvent dewaxed hydrocracked samples were considerably worse than the catalytically dewaxed feedstock and showed a general tendency to decrease the RBOT stability with increasing boiling range (25% bottoms compared to full range hydrocracked products), end of run (EOR) compared to start of run (SOR), and increased catalyst aging in the hydrocracking column.

Example 8

Table 5 demonstrates that polycyclic aromatic hydrocarbons are substantially absent in a lubricant that has been treated with high pressure catalytic dewaxing followed by hydrofinishing by very low UV absorption at 400 nm. This correlates with the solar stability results of fig. 13.

Example 9

1.73×10⁴kpa (2500psig) ratio at 2.8 x 10³The aging of the dewaxing catalyst was significantly reduced compared to kpa (400 psig). In addition, the lube pour point is 2.3 times more sensitive to temperature changes during dewaxing at higher pressures. These differences are attributed to the reduced rate of coke formation at higher pressures.

The aging of the catalyst is plotted in fig. 10. Shows the hydrodewaxing reactor (reactor 1) temperature (actual sum converted to a 5F pour point) and pour point versus days on stream. As a general matter, the aging rate is lower for low nitrogen feedstocks than for conventional solvent refining feedstocks.

High pressure catalytic dewaxing operation

At 1.73X 10⁴The catalyst was labeled at 285 deg.C (545 deg.F.) during the first two days of operation under kpa (2500psig) conditions. The overall 36 day running aging rate was negligible. Therefore, it is 1.73X 10⁴Kpa (2500psig) is expected to have an extremely long cycle length.

Low pressure catalytic dewaxing

At 2.8X 10³kpa (400psig), cycle onThe initial temperature was about 530 ° F. The initial aging rate was-14 ℃ (6.5 ° F/day) and the transition was to a lower aging rate of-15 ℃ (5.65 ° F/day). The pour point conversion of 1.3F pour point/1F change in HDW reactor temperature is effective to eliminate the HDW reactor temperature characteristic for pour point ranges from-30 deg.C to 4 deg.C (-22 deg.F to +39 deg.F).

After 29 days of operation, the pressure was increased to 2200 psi. The baseline amount of activity and the aging rate of the recovered catalyst decreased to near zero over 4 days. This is proposed to be 2.8X 10³kpa (400psig) results in increased aging rates from higher coking rates, some of which readily hydrogenate or desorb as pressure increases.

Example 10

In general, increasing the operating pressure for catalytic dewaxing tends to reduce distillate yield and correspondingly increase C₅ ^-The yield was found. Lube yield is relatively sensitive to pressure. The lube oil yield at a pour point of-15 deg.C (5 deg.F) was about 10 wt.% different compared to Solvent Dewaxing (SDW), with 70-72 wt.% catalytic dewaxing using ZSM-5 catalyst and 82 wt.% solvent dewaxing (dry wax basis). However, it should be recognized that most solvent dewaxing units produce waxes that always contain 10-30% oil. Thus, the actual solvent dewaxing yield is 74-80%.

The product yield distribution indicates that non-selective cracking occurs over the high activity, high pressure aromatic saturation catalyst at 329 deg.C (625 deg.F). The yield of lube oil was 6 wt.% lower as shown in FIG. 16 (lube oil yield versus temperature) and FIG. 17 (viscosity versus hydrofinishing severity at a fixed pour point). Most of this loss increases with increasing distillate yield. A sudden change in the properties of the lubricating oil at a hydrotreating temperature of 329 c (625F) is also indicative of non-selective cracking.

The viscosities of the low pressure and high pressure catalytically dewaxed lubricant products were similar throughout most of the hydrofinishing operating range tested (fig. 18). Pour point at-15 deg.C (5 deg.F), viscosity at 100 deg.C was 4.6cSt (116SUS @100 deg.F), and VI was 121. The viscosity of the solvent dewaxed oil is lower and the VI is higher, consistent with the difference in the way these two processes achieve their goals.

As is evident from the lubricating oil properties and yields discussed above, non-selective cracking occurred over the Arosat hydrofinishing catalyst at 329 ℃ (625 ° F). The viscosity of the lubricating oil is significantly reduced, with a corresponding reduction in VI of 3-5 numbers.

(see FIG. 18)

The primary difference between the properties of the lubricant oils obtained by low pressure and high pressure catalytic dewaxing is a result of the degree of aromatics saturation in the hydrofinishing reactor-a result of the difference in (1) the type of hydrofinishing catalyst used and (2) the hydrogen pressure. These differences are even greater for aromatic feeds such as the deeper bottoms fraction of a hydrocracking column or the products of a recycle-end hydrocracking.

Solvent dewaxing preferentially removes the heavier higher pour point waxes, while catalytic dewaxing with ZSM-5 preferentially cracks the smaller n-paraffins, which are also the highest VI components. Thus, the yield and VI of the catalytically dewaxed light duty neutral lubricant is lower. However, the low temperature viscometric properties of the catalytically dewaxed product produced are superior to those of solvent dewaxed oils of comparable viscosity.

Example 11

UV absorbance and product status were authentic for the hydrofinishing reactor conditions screened in the pilot plant study. Absorbances at 5 wavelengths-226, 254, 275, 325 and 400 nm-were used as quality indicators of the amount of aromatics, corresponding to total aromatics at 226 nm. Aromatics with 3 or more rings and 4 or more rings are represented by absorbances at 325nm and 400nm, respectively.

The use of the catalyst in Arosat HDF dramatically reduces the amount of lube aromatics. Standard catalytic dewaxing HDF catalysts designed for olefin saturation even at 1.53X 10⁴kpa (2200psi), is much less efficient (see fig. 12 and 21). As can be seen from FIG. 12, for high pressure catalytic dewaxing at approximately 274 deg.C (525 deg.F), the UV absorbance at 226nm (which isRelative to total aromatics) by a minimum-designating the span from kinetic limits to equilibrium limits. This minimum will shift to higher HDF temperatures (and higher UV absorbance) as the feed aromatics increase. Standard catalytic dewaxing HDF catalysts are kinetically limited for aromatics saturation over the temperature range studied.

In general, saturation of polycyclic aromatic hydrocarbons (400nm) is relatively easy, and within the normal hydrofinishing temperature range at high pressure, the reaction is limited by equilibrium, i.e., polycyclic aromatic hydrocarbons decrease and then increase with changes in the hydrofinishing temperature. Higher hydrogen pressure shifts the equilibrium to lower values.

Fig. 19 and 20 show UV absorbance versus aromatics content for two different hydrocracking products. One with a low aromatic content and the other with a high aromatic content. This data clearly demonstrates that the high pressure and aromatics saturation hydrofinishing catalyst is better than the high pressure hydrofinishing with the standard hydrofinishing catalyst. (see Table 6). [ TABLE 6 ]

Comparison of product Properties

HDW temperature ℃ (° F)	HDF temperature ℃ (° F)	Pressure KPa	wt.% aromatics in lubricating oils (CHg ═ 14.3)	Pour point of lubricating oil ℃ (° F)	Yield wt.% of lubrication	Fractionation of aromatic hydrocarbonsYield (lube aromatics x lube yield)/(aromatics change)
							(316)	218	2.8×103KPa(400)	15.3	-15(5)	86	0.9
(335)	218	2.8×103KPa(400)	20.7	-46(-50)	76	1.1
							(327)	218	1.53×104KPa(2200)	1.7	-15(5)	88	0.1

Example 13

Although many of the examples described above use HZSM-5 as the dewaxing catalyst, other catalysts described above may be used as the dewaxing catalyst. This is illustrated in FIG. 20, where the dewaxing catalyst was Pt/ZSM-23. FIG. 18 shows that the VI and yield of the lube oil obtained with Pt/ZSM-23 is about the same or better than the VI and yield of the lube oil obtained by solvent dewaxing.

Example 14

Some mesoporous molecular sieves were tested for their ability to convert n-paraffins, which are representative of the waxes in waxy light lubricant base oils. The n-alkane is n-hexadecane. The molecular sieves tested with this compound were ZSM-5, ZSM-23, ZSM-48, and SAPO-11. For molecular sieves, the acidity of the catalyst is altered either during synthesis of the molecular sieve or by steam treatment (which is known to be a method of reducing the activity of the molecular sieve), as determined by the "ALPHA" test. A noble metal, i.e., platinum, was added to each catalyst prepared from the molecular sieve. The concentration of platinum varies with certain molecular sieves. The following table lists the molecular sieves, their platinum content and their "ALPHA" activity.

TABLE 7

Properties of the molecular sieves

Molecular sieves	Pt，wt.％	Activity of "ALPHA	Temperature at 0.4 LHSV, 95% conversion F
				ZSM-23	0.5	30	547
ZSM-23	0.2	30	570
				ZSM-23	0.5	1	603
ZSM-48	0.83	5	619
				SAPO-11	0.7	9	600
ZSM-5	1.1	8	554
				ZSM-5	0.4	1	603
ZSM-5	0.5	280	445 at 3.0LHSV

All of these mesoporous molecular sieves are capable of providing high conversion of wax compounds such as hexadecane. The activity of the catalyst prepared from each molecular sieve may vary significantly depending on the activity of the molecular sieve in the catalyst. The amount of platinum also affects the activity. Product selectivity is affected by the type of molecular sieve, platinum content and "ALPHA" activity. Fig. 21 is a graph of the conversion of n-hexadecane and temperature conditions. FIG. 22 is a graph showing the yield of an isomeric n-hexadecane-converted compound having 16 carbon atoms and the conversion of n-hexadecane. This figure shows that ZSM-48 and SAPO-11 generally have the best selectivity for isoparaffins. If high alpha ZSM-5 is used, the selectivity is very low. However, FIG. 23 shows that ZSM-23 is very selective for the single-stranded isomer of n-hexadecane. This type of selectivity may be important in determining the VI of the lubricating oil product. Thus, it is clear that the conversion of normal paraffins or waxes to isomeric compounds of the same molecular weight requires the optimum noble metal content and acidity and pore structure of the molecular sieve for each molecular sieve used in the finished catalyst.

Claims (33)

1. A process for producing a dewaxed lubricant oil product comprising at least one hydrocracking zone, at least one hydrodewaxing zone and at least one hydrofinishing zone, the product having a pour point less than or equal to-4 ℃, a hydrogen content of at least 13.7 wt.%, a flash point of at least 200 ℃, a NOACK number of no greater than 20, a saybolt color of at least 25, a total aromatics content of less than 10 wt.%, a viscosity of at least 3.0cS at 100 ℃, a Viscosity Index (VI) of 115 or greater and excellent oxidation stability, UV light stability and thermal stability, the process comprising the steps of:

(a) hydrocracking a hydrocracked feedstock having a boiling point above 340 ℃ and a hydrogen content below 13.5 wt% at a hydrocracking inlet to convert at least 30 wt% of the feedstock to a product having hydrocarbons boiling below the initial boiling point of the feedstock;

(b) hydrodewaxing the partially unconverted material of step (a) having a kinematic viscosity at 100 ℃ of at least 3.0cS, a viscosity index VI of at least 125, a NOACK number of 20 or less, a hydrogen content of at least 14 wt.%, a pour point of at least 10 ℃ and a nitrogen content of no greater than 30ppm, by uniformly distributing and contacting with a catalyst comprising a shape selective, restricted molecular sieve having at least one channel with pores formed by rings containing 10 oxygen atoms replaced by silicon or phosphorus atoms, the molecular sieve having an acidic function, in the presence of co-added hydrogen at an elevated temperature of up to 425 ℃ (797 ° F);

(c) contacting the effluent stream from step (b) under aromatics saturation conditions with co-fed hydrogen and an effective metal hydrogenation-capable aromatics-saturated hydrofinishing catalyst at a reaction temperature of about 230 ℃. (446 ℃.) (650 ℃ F.) and a reaction pressure of at least 10,000kpa (1450psi) to obtain a dewaxed lubricant product;

(d) separating by-products from the lube product of step (c) by flashing and distillation.

2. The process of claim 1 wherein the unconverted material hydrodewaxed in step (b) has a boiling point of 315 ℃ or higher.

3. The method of claim 1, wherein step 1(a) further comprises the steps of:

(a) hydrotreating the hydrocarbon feed of step 1(a) in a hydrotreating zone containing a catalyst having hydrodenitrogenation and hydrodesulfurization activity;

(b) the hydrotreated effluent of step 2(a) is passed to a series of hydrocracking zones in which the feedstock is contacted with a hydrocracking catalyst containing macroporous amorphous material or macroporous molecular sieve and also containing hydrogenation/dehydrogenation components, the hydrotreated effluent is converted to lower boiling products at elevated temperature and pressure in the presence of hydrogen under conditions of a hydrogen partial pressure of 3448-;

(c) the effluent stream of the hydrocracking of step (b) is passed to a separation zone to remove product and the unconverted portion is passed to a vacuum distillation zone operated at a bottoms temperature of about 300 ℃ and 380 ℃ and a bottoms pressure of about 20 to 300mmHg, thereby producing a product fraction and a bottoms fraction;

(d) the product of step 3(c) is passed to the dewaxing zone of step 1 (b).

4. The process of step 3(c), wherein at least a portion of the bottoms fraction is recycled to the hydrocracking zone of step 2 (b).

5. The process of claim 1 or 2, wherein the shape selective intermediate pore size molecular sieve material of step 1(b) is selected from the group consisting of ZSM-5, ZSM-23, ZSM-35, ZSM-11, SAPO-11, or mixtures thereof, each of which catalysts is loaded with a noble metal.

6. The process according to claim 1 or 2, wherein the shape selective intermediate pore size molecular sieve of step 1(b) is HZSM-5.

7. The process of claim 5 wherein the shape selective intermediate pore size molecular sieve material has a constraint index in the range of from 0.5 to 12 and an alpha value of less than 300.

8. The method of claim 7 wherein the α value is less than 30.

9. The method of claim 8 wherein the α value is less than 10.

10. A process according to claim 5 wherein the molecular sieve material is loaded with 0.2 to 1.2% by weight of the noble metal.

11. The process according to claim 1 or 2, wherein the hydrofinishing catalyst of step 1(c) comprises at least one group VIIIA metal and at least one group VIA metal (INPAC) on a porous solid support.

12. The process according to claim 1, wherein the hydrofinishing catalyst of step 1(c) comprises nickel and tungsten metals on a fluorinated porous alumina support comprising alumina or a mixture of silica and alumina.

13. The process according to claim 1, wherein the dewaxing zone and the hydrofinishing zone are operated at substantially the same pressure, and wherein all of the dewaxed oil stream from the dewaxing stage is fed directly to the hydrofinishing zone.

14. The process of claim 10 wherein the dewaxing catalyst has an aging rate of not greater than about 0.1 ℃/day at a pressure of greater than 10,000 kpa.

15. The process of claim 1 wherein the hydrodewaxing of step 1(b) is conducted in at least two dewaxing zones.

16. The process of claim 1, wherein the hydrofinishing of step 1(c) is carried out in at least two dewaxing zones.

17. The method of claim 1, wherein the dewaxed lubricant product has a boiling point above about 370 ℃, a KV of from 4 to 10cSt at 100 ℃, and a UV absorbance at 315nm of less than 0.001L/g-cm.

18. The method of claim 17, wherein the dewaxed lubricant product has a UV absorbance at 315nm of less than 0.001L/g-cm.

19. The process of claim 1 or 2 wherein the heavy hydrocarbon feed comprises vacuum gas oil, deasphalted raffinate oil, or a mixture of both.

20. The process of claim 1 or 2 wherein the hydrodewaxing zone of step 1(b) comprises a plurality of fixed bed catalytic reactors arranged in a vertical array with quench stream hydrogen between the beds for temperature reduction.

21. The process of claim 1 or 2 wherein the hydrofinishing zone of step 1(c) comprises a plurality of fixed bed catalytic reactors in a vertical arrangement with quench stream hydrogen between the beds for temperature reduction.

22. The method of claim 1 wherein the number of NOACKs is not greater than 10.

23. The method of claim 22 wherein the number of NOACKs is not greater than 5.

24. The process of claim 2(c) wherein the NOACK number of the residuum of the vacuum distillation zone is no greater than 20.

25. The process of claim 24 wherein the NOACK number of the residuum of the vacuum distillation zone is no greater than 10.

26. The process of claim 25 wherein the NOACK number of the resid in the vacuum distillation zone is no greater than 5.

27. The process of claim 1 wherein the dewaxed lubricant oil and product has an aromatics content of no greater than 2 wt.%.

28. The method of claim 1 wherein the dewaxed lubricant product exhibits color stability after 10 days of exposure to sunlight and the atmosphere.

29. The process of claim 1 wherein the dewaxed lubricant product has a 10% distillation point of 357 ℃ or greater.

30. The method of claim 29, wherein the dewaxed lubricant product has a 10% distillation point of 413 ℃ or greater.

31. The method of claim 30, wherein the dewaxed lubricant product has a distillation point of 432 ℃ or greater.

32. The process of claim 1 wherein the dewaxed lubricant product has a pour point of from-50 to-4 ℃.

33. The process of claim 1 wherein the dewaxed lubricant product has a hydrogen content of at least 14.3 wt.% and a VI of 120 or greater.