Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G65/00—Treatment of hydrocarbon oils by two or more hydrotreatment processes only
  • C10G65/02—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only
  • C10G65/04—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps
  • C10G65/08—Treatment of hydrocarbon oils by two or more hydrotreatment processes only plural serial stages only including only refining steps at least one step being a hydrogenation of the aromatic hydrocarbons
• • 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

• High viscosity index lubricating base oils are produced from a deasphalted oil in a multizone hydrocracking process in which a sulfided nonacidic catalyst comprising one or more metals of the Group VI-B, VII-B or VHI metals is used in each reaction zone.
• a sulfided nonacidic catalyst comprising one or more metals of the Group VI-B, VII-B or VHI metals is used in each reaction zone.
• hydrogen sulfide and/or ammonia are removed from the firstzone efiluent before introducing it into the second zone.
• the first reaction zone temperature is at least 750 F. while the second reaction zone temperature is at least 700 F.
• the invention relates to a multizone hydrocracking process for the preparation of lubricating oils having a high viscosity index. It particularly relates to a process in which deasphalted oils are hydrocracked at specific temperatures and pressures to produce a lubricating oil base having a high viscosity at 210 F. and a viscosity index greater than 120.
• Lubricating oils in particular oils used for the lubrication of combustion engines such as gasoline and diesel engines, should meet certain requirements both as regards their viscosity at certain standard temperatures and their viscosity-temperature relationship. As is known, this relation is expressed by the viscosity index as proposed by Dean and Davis.
• desirable lubricating base oils will have a viscosity of more than 8 centistokes at 210 'F. and a viscosity index higher than 110.
• Multigrade lubricating oils are oils which meet viscosity requirements at 210 as well as at 0 F., thus ensuring that in winter these oils are sufliciently thin to present no difficulties in the cold start of the engine and are sufiiciently thick at the engine temperatures to per form a lubricating action.
• Such multigrade oils are designated as W/20, W/20, 5W/30, 10W/30, 2OW/30, 5 W/40, 10W/40, W/40, etc. oils.
• 5W, 10W and 20W indicate the maximum viscosity at 0 F., the socalled winter grades, while the numbers after the stroke refer to the SAE viscosity range at 210 F.
• lubricating base oils will meet the 10W/30 specification, that is a viscosity at 210 F. of at least 9.6 centistokes (es) and a viscosity index of at least 132.
• the present invention provides a process for the preparation of lubricating base oils meeting the 10W/ 30 multigrade specification Without addition of a thickener and/or VI-improver.
• the process yields lubricating base oils with a viscosity at 210 F. of at least 9.6 es. and a viscosity index of to 135.
• These lubricating oils can be formulated to 10W/30 or l0W/40 multigrade oils by addition of small amounts of thickener and/or VI- improver.
• a lubricating oil base having the desired properties is produced by treating a deasphalted oil with hydrogen in two reaction zones in the presence of a sulfided non-acidic catalyst.
• a substantially non-acidic catalyst carrier and one or more metals belonging to Groups VI-B, VII-B and VIII of the Periodic System of Elements is employed in a first reaction zone at a temperature of 760 to 830 F. and a pressure of more than 2100 p.s.i.g., after which the liquid product of the first reaction zone is subsequently passed over a sulfided catalyst of the type described in a second reaction zone, in the presence of hydrogen, at a temperature of 715 to 885 F. and a pressure of more than 2100 p.s.i.g.
• a lubricating base oil having a viscosity at 210 F. of 9.6 to 14.0 centistokes and a viscosity index of 125-140 is recovered from the liquid product of the second reaction zone.
• the liquid product of the first 'zone is substantially freed from hydrogen sulfide and/ or ammonia which are formed from sulfurand/or nitrogencontaining organic compounds which are usually present in the lubriacting oil base material.
• the simplest way to remove this hydrogen sulfide and/ or ammonia is by reduction of the pressure.
• Other methods, such as stripping with an inert gas, for example, hydrogen or nitrogen, at the pressure prevailing at the reactor outlet or at reduced pressure, can also be applied.
• a sulfided catalyst is applied in the second zone, small quantities of a sulfur compound should be present in the feed to the second zone to keep the catalyst in a sulfided state.
• the feed to the second zone should preferably contain an amount of sulfur in the range of from to 5000 p.p.m.w. (0.5% W.) and more preferably of from 100 to 2000 p.p.m.w. If residual lubricating oil base materials containing more than 1% w.
• the liquid product of the first 'zone will, after removal of hydrogen sulfide, as a rule contain sufiicient sulfur in the form of organically-bound sulfur and/or hydrogen sulfide to keep the catalyst of the second zone in the sulfided state.
• quantities of sulfided compounds such as mercaptans, carbon disulfide and the like, should be introduced such that the sulfur content lies in the range defined above.
• preferably not more than 2500 and more pref erably less than 1500 p.p.m.w. of sulfur in the form of sulfur compounds is added to the liquid product of the first zone.
• Feed to the process of the invention consists of a residual lubricating oil which is entirely or substantially free from asphalt or asphaltic material.
• a residual lubricating oil which is entirely or substantially free from asphalt or asphaltic material.
• Such an oil can be obtained by deasphalting an asphalt-containing residue with light hydrocarbons such as propane, propylene, butane, pentane or mixtures thereof.
• light hydrocarbons such as propane, propylene, butane, pentane or mixtures thereof.
• mixtures of such hydrocarbons with light alcohols such as methanol and isopropanol can be applied for the deasphalting.
• the residue is preferably a short residue obtained by vacuum distillation of a crude oil, a topped crude oil or a long residue.
• the feed may also be a long residue or the residual oil can be a mixture of a deasphalted short residue with one or more lubricating oil distillates; but these possibilities do not as a rule offer additional advantages in the process of the invention.
• the residual oil may also be a bright stock, that is a deasphalted residual oil subjected to a treatment with a solvent which is selective towards aromatics.
• the deasphalting of residual oils such as a short residue, and the conditions to be applied in such a process are known in the art.
• the viscosities of the deasphalted residual oils may vary within very wide limits (-300 cs. at 210 F.) and depend on the solvent used for the deasphalting.
• a short residue deasphalted with pentane can have a viscosity at 210 F. of 260 cs.
• the same residual oil has a viscosity at 210 F. of 160 cs. if a mixture of pentane and alcohol has been employed as a solvent for the deasphalting.
• the deasphalted residue obtained with the aid of the lightest hydrocarbons usually has a viscosity at 210 F. of from 24 to 95 cs. and a viscosity index of from '60 to 95 and the use of such a residue is preferred.
• Special preference is given to the use of a propane-deasphalted short residue (viscosity at 210 F. of from 27 to 55 cs.).
• the sulfur content of the said residual oils can vary from a value as low as 0.05% to a value as high as 8% w.
• the conditions in the first and second zones of the process according to the invention are preferably chosen such that after the first zone the viscosity index of the lubricating oil fraction of the total liquid product has been increased to 95 to 120. If the severity of the conversion in the first zone is chosen to be higher, then a relatively smaller improvement of the viscosity index occurs in the second zone but the yields of desired lubricating base oil of high viscosity and viscosity index decrease strongly.
• the process for the preparation of a lubricating base 011 according to the invention is preferably carried out at a pressure in the first and in the second zone which is higher than 2100 p.s.i.g. and more preferably at a pressure in the range of from 2500 to 4300' p.s.i.g.
• Application of pressures above 2100 p.s.i.g. in both the first and the second zones is advantageous in that the yield of desired lubricating base oil is increased.
• Particular preference is given to pressures between 2600 and 3200 p.s.i.g.
• the pressure in the second zone 15 equal to that in the first zone, but there are no overriding objections against a lower or a higher pressure in the second zone.
• the liquid product When the liquid product leaves the first zone, it is preferably first brought to a lower pressure by means of one or more high-pressure and low-pressure separators and then again brought to the pressure desired for the second zone.
• Such a procedure is very suitable to eliminate the excess hydrogen sulfide present and to increase the selectivity of the sulfided catalyst in the second zone.
• By an appropriate choice of the pressure reduction it can be ensured that sufficient hydrogen sulfide remains dissolved in the liquid product to keep the catalyst of the second zone in the sulfided state.
• the temperatures which are used in the second zone preferably lie in the range of from 715 to 885 F. Very suitable temperatures are those between 750 and 830 F. Depending on the activity of the catalsyt applied in the second zone the temperature may be lower or higher than or equal to the temperature employed in the first zone. However, the best results as regards yield, viscosity and viscosity index have been obtained in those cases where the temperature in the second zone was at least equal to and preferably 10 to 50 F. higher than the temperature in the first zone. Suitable temperatures for the first zone lie in the range of from 760 to 830 F.
• the space velocity applied can vary from 0.5 to 5 liters of feed per liter catalyst per hour for both zones. In order to make the operation more severe, in general relatively low space velocities will be applied, from 0.7 to 1.5.
• the hydrogen gas supply may'vary within wide limits and is as a rule between 250 and 5000 N1. hydrogen per kilogram feedstock.
• the process according to the invention can be carried out in such a way that the total quantity of hydrogen required for the first and second zones is directly added to the feed to the first zone or in such a way that in each zone hydrogen is added separately. Which method is chosen depends on whether or not hydrogen sulfide and/or ammonia is removed intermediately by pressure reduction. Thus, if the pressure is reduced between the first and the second zones, as a rule hydrogen will have to be supplied, whereas in the case where no intermediate pressure reduction is applied hydrogen can be added in the second zone.
• the catalysts applied in the first and second zones should have a substantially non-acidic catalyst carrier in order to avoid excessive cracking under the reaction conditions employed. Acidity of the catalyst carrier promotes those hydrocarbon conversions which are based on the formation of carbonium ions, that is dealkylation and hydrocracking.
• Suitable non-acid catalyst carriers which can be used in the process of the invention are the heat-resistant and chemically inert inorganic oxides such as alumina, boria, silica, magnesia, zirconia and the like. In addition, mixtures of some of these oxides can be applied, such as alumina-magnesia or magnesia-zirconia, but mixtures of oxides which contain silica are entirely unsuitable.
• the most preferred catalyst carrier is alumina, in particular alumina containing less than 1% w. silica.
• the alumina may contain small quantities of alkali and alkaline earth metals such as potassium, sodium, magnesium and calcium to ensure the non-acidic character of the carrier. Eligible quantities are from 0.05 to 1.5% w. calculated as oxide. From the foregoing it follows that commercial aluminas containing silica in quantities of more than w., or halogens such as chlorine or fluorine, are unsuitable as catalyst carrier for the process according to the invention.
• the metals of the Groups VI-B, VII-B and VIII to which preference is given are molybdenum, tungsten, rhenium and the metals from the Iron Group of Group VIII, namely cobalt, nickel and iron. These metals can be present on the catalyst carrier as oxides or sulfides; for the process of the invention the catalysts are applied in the sulfided state and, if necessary, these catalysts should therefore be sulfided beforehand. Preference is given to the use of sulfided catalysts which contain at least one metal from Group VI-B and at least one metal from Group VIII (Iron Group).
• Suitable combinations are cobalt-molybdenum, nickel-molybdenum, nickel-cobalt-molybdenum, tungsten-nickel or tungsten-nickel-rhenium. These metals can be present on the carrier in quantities of from 3 to 35% w. for the metals from Group VI-B and of from 0.5 to w. for the metals from Group VIII (Iron Group).
• the liquid product of the first zone will contain products boiling below the lubricating oil range. Although these products can be removed from the said liquid product by distillation, this is by no means necessary and the process according to the invention offers the advantage that, preferably after intermediate pressure reduction as discussed hereinbefore, the liquid product from the first zone can as a whole be introduced into the second zone.
• the product of the second zone will also contain lowerboiling products, such as gasoline, kerosene and gas oil. These lower-boiling non-lubricating oil products must be separated from the lubricating-oil fraction, which takes place by means of distillation. .As a rule the fraction boiling above 700 F. is recovered as lubricating oil fraction.
• the lubricating base oil obtained from this fraction after dewaxing has a minimum viscosity index of 120; as a rule this fraction has a viscosity index in the range of from 125 to 140. Further fractionation of this fraction 700 F. may yield several lubricating oil fractions with different viscosities and viscosity indices.
• the lubricating base oils of the invention are usually obtained as a fraction boiling above 900 F. with a viscosity index of at least 120 and a viscosity at 210 F. higher than 9.6 cs. (after dewaxing).
• the initial boiling point of this base oil may vary from 8-60 to 960 F.
• lubricating oil fractions or lubricating base oils can be obtained which have a high viscosity at 2.10" F. and at the same time a high viscosity index.
• the viscosities vary from 9.6 to 14.0 cs. (at 210 F.) at a viscosity index of from 120 to 135.
• Very suitable lubricating base oils are those which have a viscosity of at least 9. 6 cs. and a viscosity index of at least 128.
• the liquid product of the second reaction zone is preferably recovered as a lubricating oil fraction with a viscosity index of at least 132 and a viscosity at 210 F. of at least 9.6 cs., that is a l0W/30 lubricating base oil.
• the lubricating base oils obtained according to the invention can also, if desired, be mixed with other lubricating base oils, such as distillate oils.
• the process according to the invention can be carried out by any method known in the art, For example, both in the first and in the second reaction zones a fluidized catalyst bed or a fixed bed can be applied and the lubricating oil base material to be treated can be passed through the bed together with hydrogen in an upward or downward direction. Recycle of hydrogen to the first or second zones may, or may not, be applied.
• the hydrogen treatment according to the process of the invention preferably takes place under so-called trickle conditions in both zones. Under these conditions the lubricating oil base material, part of which may be in the vapor and part in the liquid phase, passes in the presence of hydrogen or a hydrogen-containing gas in a downward direction over a fixed catalyst bed; the liquid lubricating oil base material flows as a thin fihn over the catalyst particles.
• a hydrogen-containing gas mixture can be used, for example, a mixture of hydrogen and methane.
• the hydrogen-containing gas mixture pref erably contains more than 50% v. hydrogen. If an excess of hydrogen is applied, it is advantageous to recycle the used hydrogen to the previous reaction zone, for example, after removal of undesired compounds such as ammonia and excess of hydrogen sulfide.
• the process according to the invention will be further elucidated with the aid of the following examples.
• the catalysts applied have first been sulfided at a temperature of 600 F. and a pressure of about 14 p.s.i.g., with the aid of a H /H S mixture containing 10% v. hydrogen sulfide.
• Dewaxing of the various lubricating oil fractions has in all cases been effected at 4 F. using a methyl ethyl ketone/toluene mixture (50/50), unless specified otherwise.
• the viscosity index has been determined according to ASTM-D'-567.
• EXAMPLE I A deasphalted residual oil obtained by propane treatment of a short residue of a crude oil originating from the Middle East was treated with hydrogen in a two-zone process in the presence of a commercial desulfurization catalyst.
• the liquid product of the first zone was substantially freed from hydrogen sulfide by passing it successively through a high-pressure and a low-pressure separator. Before it was introduced into the second zone, the liquid product from the low-pressure separator of the first zone was again pressurized and heated together with fresh hydrogen.
• the total liquid product from the lowpressure separator of the second zone was separated by distillation into a product boiling mainly below 700 F. (fraction 700 F.) and a fraction boiling above 700 F. (fraction 700 F.), from which fraction the desired lubricating base oil with high viscosity and viscosity index can be obtained by distillation.
• DAO deasphalted residual oil
• the catalyst applied in both the first and the second zones had the following composition: 3.1 p.b.w. Ni, 11.7 p.b.w. Mo and 100 p.b.w. A1
• the catalyst was sulfided beforehand in the way indicated.
• the liquid product from the low-pressure separator of the first zone had a sulfur content of 0.02% w. S, which was sufficient to keep the catalyst in the second zone in the sulfided state.
• the pressure applied in both zones was 2850 p.s.i. g. and the temperature of the second zone was varied from 750 to 805 F.
• the liquid hourly space velocity in both zones was 1.0 and the hydrogen gas supply was 2000 N1. per liter feedstock.
• Table 1 shows the yields of oil boiling above 700 F. and 900 F. obtained after distillation and dewaxing of theliquid product of the second zone.
• the dewaxed oil boiling above 700 F. is a base oil which can be separated into the various lubricating oil fractions by distillation.
• the oil boiling above 900 F. has been obtained from the base oil by distillation and can be employed for the preparation of multigrade lubricating oils because of its high viscosity at 210 F. and its high viscosity index.
• Example II The experiments of Example I were repeated with the aid of an experimental catalyst containing a slight quantity of added alkali in the carrier.
• the catalyst had a composition of 2:35 p.b.w. Ni, 29.4 p.b.w. W, 0.4 p.b.w. Pa and 100 p.b.w. A1 0 and had been obtained as folows.
• the calcined alumina was next impregnated with the combined solution and after standing for 15 minutes dried at 250 F. After drying the impregnated alumina was again calcined at 930 F. for 3 hours.
• the catalyst thus obtained was applied in the second zone of the process according to the invention.
• Example II After sulfiding the catalysts in the first and second zones the experiments were carried out under the same conditions as regards pressure, space velocity and hydrogen gas supply as in Example I.
• the liquid product from the low-pressure separator had a sulfur content of 0.02% w. S, which was suflicient to keep the catalyst in the second zone in the sulfided state.
• Example III The experiments of Example II were repeated at higher temperatures for the first zone and using the same catalysts in the first and second zones. The results obtained after dewaxing of the various product streams are presented below.
• EXAMPLE IV The following example has been included to show that first-zone pressures below 1775 p.s.i.g. are undesirable.
• the feed applied was the same as used in the previous examples.
• the first-zone catalyst was a commercial desulfurization catalyst and had the following composition: 3.9 p.b.w. Co, 9.8 p.b.w. Mo, and 100 p.b.w. A1
• the second-zone catalyst was the same Ni/Mo/Al o catalyst as that employed in Example I for both the first and the second zones.
• the pressure applied in the first zone was 710 p.s.i.g., while the liquid hourly space velocity was 2.0.
• the hydrogen gas supply was 500 N1. per liter feed.
• the conditions in the second zone were a pressure of 2850 p.s.i.g., a space velocity of 1.0 liter, and 2000 N1. hydrogen per 1 liter feed.
• the experiments were carried out after the catalysts in the first and second zones had been sulfided in the usual way.
• EXAMPLE V This example demonstrates infiuence'of the removal of hydrogen sulfide between the two zones on the yield of lubricating base oil.
• the deasphalted residual oil of Example I was treated with hydrogen in two zones at a pressure of 2850 p.s.i.g. In each zone fresh hydrogen was supplied.
• the catalyst applied in both zone was the experimental alkali-metalcontaining W/Ni/AI O catalyst described in Example II.
• the liquid hourly space velocity was 1.0 and the hydrogen supply 2000 N1. per liter of feed for each of l the two zones.
• the temperature in the first zone was In one experiment the liquid product from the reactor of the first zone was introduced into the reactor of the second zone without intermediate removal of hydrogen sulfide; in another experiment this product was substantially freed from the hydrogen sulfide formed in the first zone by pressure reduction and subsequently it was repressured and introduced into the reactor of the second zone. The results are shown below.
• Example VI The experiment of Example V with intermediate hydrogen sulfide removal was repeated at a pressure of 2100 p.s.i.g. for both zones. The results are summarized in the table below.
• a process for the production of high viscosity index lubricating oils which comprises hydrocracking a deasphalted residual lubricating oil in a first reaction zone at a pressure of at least 2100 p.s.i.g. and a temperature of 760 to 830 F., hydrocracking the liquid product from the first reaction zone in a second reaction zone at a temperature of 715 to 885 F., the hydrocracking in each reaction zone being elTected in the presence of hydrogen over a sulfided catalyst consisting essentially of a nonacidic support selected from the group consisting of alumina, boria, silica, magnesia and zirconia, and a hydrogenation component selected from the group consisting of Group VI-B, Group VI'I-B, Group VIII and mixtures thereof, and recovering from the second reaction zone liquid product a lubricating oil base which on dewaxing has a viscosity at 210 F. of 9.6 to 14.0 centistokes and a vis
• a process for the production of a lubricating base oil which on dewaxing has a viscosity at 210 F. of at least 9.6 centistokes and a viscosity index of at least 132 which comprises hydrocracking a deasphalted residual lubricating oil having a viscosity at 210 F. between 27- 55 centistokes and a viscosity index between 60-95 in a first reaction zone at a temperature of 760-830" F. to obtain a liquid product which on dewaxing has a viscosity index between 95-120, substantially removing hydrogen sulfide and ammonia from said liquid product, hydrocracking same in a second reaction zone at a temperature of 10-50" F. higher than the first reaction zone,
• the hydrocracking in each reaction zone being effected at a pressure of 2600-3200 p.s.i.g. in the presence of hydrogen over a sulfided catalyst consisting essentially of a non-acidic alumina support containing less than 1% w. silica and from 0.05 to 1.5% w. alkali and alkaline earth metal oxides, and a hydrogenation metal component selected from the group consisting of 05-10% w. Iron Group, 3-35% w. VI-B and mixtures thereof.

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

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Cited By (20)

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• 1969
  • 1969-06-04 NL NL6908525A patent/NL6908525A/xx unknown
• 1970
  • 1970-05-20 US US39871A patent/US3682813A/en not_active Expired - Lifetime
  • 1970-05-25 BE BE750867D patent/BE750867A/nl unknown
  • 1970-06-02 FR FR7020125A patent/FR2045833B1/fr not_active Expired
  • 1970-06-02 DE DE19702027042 patent/DE2027042A1/de active Pending

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