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
  • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
  • C10G45/58—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds to change the structural skeleton of some of the hydrocarbon content without cracking the other hydrocarbons present, e.g. lowering pour point; Selective hydrocracking of normal paraffins
  • C10G45/68—Aromatisation of hydrocarbon oil fractions
• • 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
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/10—Lubricating oil

Definitions

• This invention relates to lubricating base oils and is particularly concerned with a process for the manufacture of such base oils with a high viscosity index and to lubricating base oils which can be obtained by that process.
• Lubricating base oils are derived from various mineral crude oils by a variety of refining processes, generally directed to obtaining a lubricating base oil with a suitable viscosity index for the intended end use.
• the preparation of high viscosity index lubricating base oils can be carried out as follows. A crude oil is separated by distillation at atmospheric pressure into a number of distillate fractions and a residue, known as long residue. The long residue is then separated by distillation at reduced pressure into a number of vacuum distillates and a vacuum residue known as short residue. From the vacuum distillate fractions lubricating base oils are prepared by refining processes which include wax removal from the vacuum distillate fractions. From the short residue asphalt can be removed by known deasphalting processes to give a deasphalted oil from which wax can subsequently be removed to yield a residual lubricating base oil, known as bright stock. The wax obtained during refining of the various lubricating base oil fractions is designated as slack wax.
• Such slack waxes can be catalytically hydrotreated to yield high viscosity index lubricating base oils using processes such as those described in GB 1,429,494 and European patent application No. 324 528.
• the high viscosity index base oils obtained by such processes have excellent characteristics in many respects, especially as they obviate the need for the addition of polymeric viscosity index improvers.
• they have a low aromaticity when compared with lubricating base oils of lower viscosity index.
• they have a reduced ability to solubilize other materials, for example materials resulting from oxidation reactions which occur in the commercial lubricants prepared therefrom.
• the present invention is directed to the preparation of novel lubricating base oils having a high viscosity index together with comparatively high aromaticity. Surprisingly it has been found that such aromatics-containing base oils can be obtained by dehydrogenating and selectively rehydrogenating a high viscosity index lubricating base oil while still maintaining the desired high viscosity index.
• one aspect of the present invention provides a novel process for introducing aromaticity to a lubricating base oil comprising contacting a lubricating base oil feedstock having a high viscosity index with a dehydrogenating catalyst and recovering a product having enhanced aromaticity therefrom.
• high viscosity index is understood a viscosity index of at least 125 as determined by ASTM D-567.
• the feedstock preferably has an extra high viscosity index of at least 135.
• At least a portion of the product having enhanced aromaticity may be subjected, in accordance with a further aspect of the present invention, immediately downstream of the dehydrogenation or after further processing and/or transportation, to hydrotreating in the presence of hydrogen and a suitable catalyst and recovering a hydrotreated product therefrom.
• the hydrotreating does not substantially decrease the aromaticity, so that there is obtained a product of increased aromaticity from which olefinic unsaturation has substantially been removed by the hydrotreatment. Furthermore, the product has been found to maintain a high viscosity index, together with an increased aromatic content.
• the aromatic content is increased by contact with the dehydrogenating catalyst by an amount of at least 3 mmol/100 g.
• lubricating base oils having an extra high viscosity index of at least 135 and an aromatic content of at least 3 mmol/100 g.
• These base oils may be the direct products of the dehydrogenation, containing some olefinic unsaturation, or the products of the subsequent hydrotreatment to give base oils from which the olefinic unsaturation has substantially been removed.
• the lubricating base oil feedstock having a high viscosity index may be obtained for example by the processes described in GB 1,429,494 and EP 324 528.
• the viscosity index as determined by ASTM D-567 is at least 125 and is preferably at least 135, more preferably above 140.
• the base oils suitably also have a low pour point below -10 °C (as determined by ASTM D-27).
• the dehydrogenating catalyst employed to introduce aromaticity to the lubricating base oil is preferably a composite catalyst comprising a Group VIII noble metal component, a Group IVA metal component and a refractory oxide support.
• the Group VIII noble metal component is preferably platinum and is preferably present in an amount of 0.1 to 1 %wt, preferably 0.3 to 0.5 %wt.
• the Group IVA metal component is preferably tin and is preferably present in an amount of 0.1 to 1 %wt, preferably 0.3 to 0.5 %wt.
• the refractory oxide support is preferably alumina but may also be materials such as silica, silica-alumina, magnesia, zirconia, titania or mixtures thereof.
• the dehydrogenation reaction is normally carried out at a relatively high temperature and moderate pressure. Suitable temperatures are in the range of 300 °C to 600 °C, preferably from 400 to 500 °C, with a hydrogen partial pressure of 1 to 30 bar, preferably from 5 to 15 bar. Suitable space velocities range from 0.2 to 20, preferably from 2 to 10 kg/l catalyst.h. A suitable gas/feedstock ratio ranges from 200 to 2500 Nl/kg, preferably from 500 to 1200 Nl/kg.
• the product having increased aromaticity may be subjected to subsequent hydrotreating immediately downstream of the dehydrogenation and with or without removal of, for example, gaseous products.
• the product may be subjected to further processing, such as deep dewaxing, solvent extraction and/or transportation to a separate station for subsequent hydrotreatment.
• the catalyst used in the hydrotreatment contains at least one hydrogenating metal component.
• the metal component is suitably selected from the Groups VIB and/or VIII of the Periodic Table of the Elements. These Groups include the noble metals platinum and palladium. It is however preferred to use nickel and/or cobalt, and molybdenum and/or tungsten compounds.
• the amount of nickel and/or cobalt present in the catalyst can suitably vary between 1 and 20% by weight, calculated as metal on total catalyst, preference being given to amounts in the range of 1.5 to 12% by weight.
• the amounts of molybdenum and/or tungsten may advantageously vary between 5 and 40% by weight, calculated as metal on total catalyst, preference being given to amounts in the range of 8 to 30% by weight.
• the metal components may be incorporated on a support by any conventional technique, such as impregnation, dry-impregnation, precipitation or a combination thereof.
• Any suitable support material may be used, such as the refractory oxides silica, alumina, silica-alumina, magnesia, zirconia, titania or mixtures thereof.
• Silica, silica-alumina and alumina are preferred support materials, in particular alumina.
• Natural and synthetic crystalline aluminosilicates can also be used, such as faujasite-type zeolites, in particular zeolite Y, mordenite-type zeolites and ZSM-5 type zeolites, or mixtures containing such a zeolite.
• the catalysts are normally sulphided and may be fluorided by techniques known in the art.
• the catalyst preferably further comprises phosphorus, advantageously in an amount of from 0.5 to 12% by weight calculated as elemental phosphorus, based on total catalyst.
• the hydrotreating reaction is suitably carried out under comparatively mild conditions.
• Suitable temperatures are in the range of 100-400 °C, preferably from 200-300 °C with a hydrogen partial pressure in the range of 20 to 150 bar, preferably from 40 to 60 bar.
• Suitable space velocities range from 0.1 to 5 kg/l catalyst.h, preferably from 0.5 to 2 kg/l catalyst.h, while a suitable gas/feedstock ratio ranges from 200 to 2000 Nl/kg, preferably from 400 to 1000 Nl/kg.
• a high viscosity index lubricating base oil was used as feedstock. This oil had the following characteristics: kinematic viscosity at 100 °C (Vk 100) 5.39 mm2/s pour point -18 °C viscosity index 144.4 aromatics content (mmol/100 g) mono 0.388 di 0.010 poly 0.017 bromine index (mg/100 g) 10
• the feedstock was used for a series of dehydrogenation experiments in an automated one-reactor trickle-flow unit under gas once-through mode of operation and using temperatures as given in Table 1, a hydrogen pressure of 10 bar, a gas/feedstock ratio of 700 Nl/kg, and a space velocity of 4 kg/1.h.
• the catalyst employed was a platinum/tin catalyst on a lithium-neutralized alumina support and contained 0.40 %wt platinum and 0.41 %wt tin, with an initial pore volume of 0.93 cm3/g and an initial surface area of 131 m2/g. Aromatics content was determined by UV absorption.
• a high viscosity index, high aromatics lubricating base oil obtained as described in Example 1 and having the properties given in Table 2 below was hydrotreated in a one-reactor micro-flow unit under gas once-through mode of operation.
• the conditions of operation were a temperature of 260 °C, a hydrogen pressure of bar, a gas/feedstock ratio of 500 Nl/kg and a space velocity of 1 kg/l.h.
• the catalyst employed was a hydrotreating catalyst comprising 2.5% by weight of nickel, 13.5% by weight of molybdenum and 2.9% by weight of phosphorus on alumina, the percentages being based on total catalyst.
• Aromatics content was determined by UV absorption.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Crystallography & Structural Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Lubricants (AREA)
• Catalysts (AREA)

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Cited By (1)

Citations (4)

• 1989
  • 1989-02-14 FR FR8901874A patent/FR2643084A1/fr not_active Withdrawn
• 1990
  • 1990-02-09 DE DE1990606371 patent/DE69006371T2/de not_active Expired - Fee Related
  • 1990-02-09 EP EP19900200321 patent/EP0383395B1/de not_active Expired - Lifetime
  • 1990-02-09 JP JP2862590A patent/JPH02247297A/ja active Pending
  • 1990-02-09 ES ES90200321T patent/ES2049909T3/es not_active Expired - Lifetime
  • 1990-02-12 CA CA 2009830 patent/CA2009830A1/en not_active Abandoned

Patent Citations (4)

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