CN1137059A - Process for preparation of lubricating base oils - Google Patents

Abstract

The present invention provides a process for the preparation of a lubricating base oil comprising the steps of: (a) contacting a hydrocarbon oil feed in a first stage with hydrogen in the presence of a catalyst comprising at least one Group VIII noble metal component on an refractory oxide support; (b) contacting the liquid effluent in a second stage with hydrogen in the presence of a hydroconversion catalyst under hydroconversion conditions, and (c) recovering at least one lubricating base oil having a viscosity index of at least 80.

Description

The method for preparing lubricating base oil

The present invention relates to a kind of method for preparing lubricating base oil, this method comprises two continuous hydrogenation step of converting.

Two step hydroconversion process of the known preparation lubricating base oil in present technique field, the example of these class methods is disclosed in british patent specification 1,546,504, european patent application 0,321,298 and United States Patent (USP) 3,494,854; 3,459,656; In 3,974,060 and 4,518,485.From these open source literatures as can be seen, the common purposes of the first step of two step hydroconversion process be to remove exist in the hydrocarbon oil feed nitrogenous-and sulphur-compound and the aromatic substance that exists in the charging is hydrogenated at least to a certain degree.Afterwards, in second step, further reduce arylide content, often also carry out the effluent dewaxing that the first step is obtained by the hydroisomerized wax molecule simultaneously by hydrogenation and/or hydrocracking.Therefore the hydrogenation conversion catalyst of the first step and the second step usefulness can fully play their purpose effects separately.From above-mentioned prior art document as can be seen, the first step catalyzer generally includes VIII family non-noble metal components and the group vib metal component that is stated from the refractory oxide carrier.Therefore, normally used the first step catalyzer comprises and is stated from aluminum oxide, the nickel-molybdenum on silica-alumina or the fluorided alumina carrier, nickel-tungsten or cobalt-molybdenum.The suitable second step catalyzer comprises the VIII family noble metal component that is stated from the refractory oxide carrier and optional group vib metal component.As VIII family metal ingredient, platinum and/or palladium are that element form or oxide compound or sulphided form all be disclosed is useful.As the refractory oxide carrier, can applying silicon aluminate (zeolitic material) and inorganic oxide (as, silicon-dioxide, aluminum oxide and soft silica-aluminum oxide) or its mixture.

Though in the two step hydrogenating conversion process of above-mentioned prior art many can carrying out satisfactorily arranged, for the efficient of improving one's methods, still allows some leeway.Specifically, the first step service temperature leaves room for improvement.Owing in the first step hydrocracking, applied higher service temperature, that is to say in the first step, to help forming multi-nucleus aromatic compound.Therefore, these multi-nucleus aromatic compounds of formation must be removed in second step, this means that the hydrocracking condition should be fully strict to hydrogenation and/or the poly-aromatic substance of the described multinuclear of hydrocracking in second step.On the other hand, reduce the first step service temperature and will make that charging is unlikely to be transformed into valuable product, from economic aspect, this is undesirable.

The object of the invention is to provide a kind of two step hydroconversion process that prepare lubricating base oil, thereby the first step can be operated under than the lower service temperature of temperature commonly used, still obtains the product with good viscosity index simultaneously under industrial noticeable productive rate.Obviously, this method does not have the requirement of what strictness to used equipment, so can operate under lower running cost, still keeps industrial noticeable productive rate simultaneously.In addition, the polynuclear aromatic material forms and is hinting also that seldom these materials seldom remain in the final base oil, considers that from environment and base oil quality this wishes.So the object of the invention provides a kind of improved two step hydroconversion process that prepare lubricating base oil.More particularly, the object of the invention is to provide a kind of method for preparing lubricating base oil, and this method can be produced the lubricating base oil of high viscosity index (HVI) under the operational condition of low demand, still have industrial noticeable productive rate simultaneously.

By selecting specific the first step hydrogenation conversion catalyst to realize these purposes, described catalyzer is higher than the first step catalyst activity commonly used, therefore can obtain under lower service temperature and the identical productive rate of the first step catalyzer commonly used.

So, the present invention relates to a kind of method for preparing lubricating base oil, may further comprise the steps:

(a) the first step in the presence of a kind of catalyzer that comprises at least a VIII family noble metal component that is stated from the refractory oxide carrier, makes the hydrocarbon ils material contact with hydrogen;

(b) in second step, under the hydrocracking condition, in the presence of hydrogenation conversion catalyst, liquid efflunent is contacted with hydrogen; And

(c) at least a viscosity index of recovery is at least 80 lubricating base oil.

The suitable hydrocarbon ils material that uses in the step (a) of the inventive method is the height hydrocarbon mixture of (as, heavy oil fraction) that boils.Particularly boiling range to small part those heavy oil fractions of being higher than lubricating base oil are suitable for and make hydrocarbon ils material of the present invention.Have been found that to be particularly suitable for using the reduced pressure distillate that obtains by atmospheric residue, that is, and the cut that the residual fraction that is obtained by air distillation crude oil as required by underpressure distillation obtains.The boiling range of this reduced pressure distillate is generally 300-620 ℃, is advisable with 350-550 ℃.But, also can use the de-asphalting residual oil cut that comprises diasphaltene atmospheric residue and diasphaltene decompression resistates, (Fischer-Tropsch wax raffinate, slack wax (the particularly material that is obtained by the wax distillate dewaxing of hydrotreatment) and hydrocracker bottom fraction (hydrogenation wax) also are the raw materials that is applicable to the inventive method to synthetic wax raffinate simultaneously.Suitable hydrogenation wax is that those effective cut points are 320 ℃ or above, preferred 370 ℃ or above material.

The catalyzer that is used for the first step hydrocracking is a VIII family noble metal-based catalysts.If use is not have sulfur-bearing-and the hydrocarbon ils material of nitrogenous-compound basically, and so this catalyzer should vulcanize before operation, so as to guarantee catalyzer to the sulfur-bearing that exists in the charging-and nitrogenous-compound enough tolerances are arranged.If catalyzer cures in the case, then its sulphur tolerance can be too low under operational condition, when therefore catalyzer can poison rapidly when hydrocarbon ils material under the operational condition contacts.Have only the hydrocarbon ils material do not have basically sulfur-bearing-and and the situation of nitrogen-compound under, for example when using synthetic wax, just can omit the sulfuration of noble metal-based catalysts as charging.But as a rule, noble metal-based catalysts must sulfuration before operation.

Sulphurized catalyst can be realized by method known in the art, for example referring to european patent application 0,186,254; 0,329,499; 0,448,435 and 0,564,317 and International Patent Application WO 93/02793 and WO94/25157.Sulfuration can be in other place or the original place carry out, that is: make unvulcanized catalyzer and suitable vulcanizing agent (as, hydrogen sulfide) contact.The hydrocarbon ils that contains a large amount of sulfocompounds also can be used as vulcanizing agent.Then, being raised to by room temperature gradually under 150-250 ℃ the temperature, this oil is contacted with catalyzer.Catalyzer was kept under this temperature 10-20 hour.Subsequently, make temperature be raised to service temperature gradually.The another kind of selection is to use the hydrocarbon ils material, and it contains a large amount of sulfocompounds usually as vulcanizing agent.In the case, unvulcanized catalyzer can be contacted with charging under unlike the operational condition exacting terms.Typically, the hydrocarbon ils material should comprise that 0.5wt.% sulfocompound (described weight percentage representative is with respect to the amount of the elementary sulfur of charging total amount) is so that can be used as vulcanizing agent at least.From cost and efficient, general preferred vulcanization in situ catalyzer that is: earlier the unvulcanized catalyzer reactor of packing into, under suitable cure conditions, makes it contact with vulcanizing agent then.

The refractory oxide carrier of the first step hydrotreating catalyst can be any inorganic oxide, and silico-aluminate or its combination selectively mix with the inert binder material arbitrarily.The example of suitable refractory oxide comprises oxide compound, as two or more mixtures of aluminum oxide, silicon-dioxide, titanium oxide, zirconium white, boron oxide, silica-alumina, fluorided alumina, fluorinated silica-aluminum oxide and these materials.In a preferred embodiment, a kind of acid carrier is used as the refractory oxide carrier as aluminum oxide, silica-alumina or fluorided alumina.The refractory oxide carrier also can be a silico-aluminate.Synthetic and natural silico-aluminate all can use.Example is zeolite-β, faujusite and zeolite Y.The preferred aluminosilicate of prepare using is aluminum oxide-or the zeolite Y of silica bound.

The VIII family noble metal component of the first step hydrogenation conversion catalyst is suitably platinum (Pt) and/or palladium (Pd) component.If catalyzer cures before operation, then noble metal component usually in course of normal operation the form with sulfide exist, but its part can exist with element and/or oxide form well.Except the VIII noble metal component, on catalyzer, also can there be non-noble metal VIII family's component and/or group vib component.Therefore, suitable nickel (Ni), cobalt (Co) and/or chromium (Cr), molybdenum (Mo) or the tungsten (W) that occurs with its sulphided form also can exist on the catalyzer.In the group vib metal, preferred tungsten and chromium.So the example of most suitable the first step catalyzer is that those are disclosed in european patent application 0,653,242 and International Patent Application WO 96/03208 in noble metal-based catalysts.The object lesson of appropriate catalyst comprises PdCr and the PdW on zeolite Y, aluminum oxide bonded zeolite Y, fluorided alumina bonded zeolite Y, hydrogen silica-alumina or the fluorided alumina that is stated from silica bound.Other example is zeolite Y, PtPd/ aluminum oxide bonded zeolite Y and the PtPd/ silica-alumina of Pt/ silica-alumina, PtPd/ silica bound.All catalyzer of mentioning vulcanize before being preferably in operation.Particularly preferred the first step catalyzer is sulfurized PdW/ silicon-dioxide-or aluminum oxide bonded zeolite Y, sulfurized PdW/ silica-alumina and sulfurized PdW/ fluorizated aluminum oxide.

The second step hydrocracking of the inventive method, that is, step (b) according to the type of used hydrogenation conversion catalyst, can comprise hydrogenation, hydrogenating desulfurizationization, hydrodenitrificationization, hydroisomerization paraffin molecule, and any two or more combinations of these methods.The hydrocracking paraffin molecule also can carry out in step (b), but only pays reaction as (small) of above-mentioned one or more hydroconversion reactions.Therefore, the hydrogenation conversion catalyst that uses in the step (b) will not be the catalyzer that is specially adapted for the hydrocracking paraffin molecule.

The hydrogenation conversion catalyst that is used for the inventive method step (b), promptly the second step catalyzer can be to be active known any catalyzer (its objective is and produce lubricating base oil) in hydrogenation, hydrogenating desulfurizationization, hydrodenitrificationization and/or hydroisomerization gained hydrocarbon in principle.

So the second step catalyzer that the first kind is suitable for is to comprise at least a VIII family's metal component and the optional at least a group vib metal component hydrogenation catalyst as hydrogenation component.This class catalyzer has hydrogenation activity, also can have hydrogenating desulfurizationization and/or hydrodenitrification activity.Usually they do not have any relevant hydroisomerization activity.Suitable VIII family metal component comprises precious metal and base metal and/or its compound, normally oxide compound and/or sulfide.So the second step catalyzer can comprise one or more non-noble metal VIII family's nickel (Ni) or cobalt (Co) and/or one or more precious metals VIII Pt of family and Pd.In this regard, notice that then this catalyzer suits to cure at least in part, so that improve its sulphur tolerance if noble metal component is present on the second step catalyzer before operation.Much less, sulphidity depends on the sulphur content of the first step effluent.Under enough low the first step effluent sulphur content, can omit the sulfuration of the second step noble metal-based catalysts.

Except VIII family metal component, the second step catalyzer also can comprise a kind of group vib metal component, and it can be Cr, Mo and/or W element, oxide compound and/or sulphided form.The second step support of the catalyst can be the refractory oxide carrier also, and comprises the listed same vehicle of above the first step catalyzer.Comprise under a kind of VIII family base metal situation at the second step catalyzer, use phosphorus (P) more favourable as promotor.At this moment, the example of the second suitable step catalyzer comprises NiMo (P)/aluminum oxide or fluorided alumina, CoMo (P)/aluminum oxide, NiW/ fluorided alumina, PdW/ silica-alumina, the zeolite Y of fluorided alumina or silica bound.

The second step catalyzer that second class is suitable is that those mainly have the active catalyzer of hydroisomerization.If the main purpose of step (b) is to reduce the pour point of the first step effluent, promptly dewaxing then can be used these catalyzer.Hydroisomerisation catalysts is known in the art, usually based on medium hole dimension zeolitic material, and suitable at least a VIII family metal component, preferred Pt and/or the Pd of comprising.At this moment, suitable zeolitic material comprises ZSM-5, ZSM-22, ZSM-23, ZSM-35, SSZ-32, ferrierite, zeolite-β, mordenite and silicon-dioxide-aluminophosphates, for example SAPO-11 and SAPO-31.The example of suitable hydroisomerisation catalysts is the material of introducing in International Patent Application WO 92/01657.Because hydroisomerisation catalysts is generally at a good pace poisoned by sulfocompound, so the first step effluent must have low sulphur content before entering for second step.

The amount of the different metal that exists on the first and second step catalyzer can change in the tolerance.The suitable amount with 0.1-10, preferred 0.2-5wt.% of VIII family precious metal is present on the first and second step catalyzer, and described weight percentage representative is with respect to the amount of metal (in element) of catalyzer gross weight.Similarly, the suitable amount with 1-25, preferred 2-15wt.% (with respect to the gross weight of catalyzer, in element) of VIII family base metal is present on the second step catalyzer.If all exist, the suitable amount with 5-30, preferred 10-25wt.% (with respect to the catalyzer gross weight, in element) of group vib metal was present on first and second steps.

Operational condition is the condition that is used for relevant hydrocracking operation traditionally in the first and second hydrocracking steps.So service temperature is 250-500 ℃, working pressure is the 10-250 crust, and weight hourly space velocity (WHSV) is per hour 0.1-10kg (kg/lh) of every liter of catalyzer, preferred 0.5-5kg/lh, hydrogen and the preferred 100-2000 liter/hydrogen of the ratio of oil/every liter of oil.But, as noted above, under the ultimate yield that lubricating base oil is given, be used for the first step catalyzer of the present invention and allow lower first step service temperature, therefore thereby reduced the amount of the polynuclear aromatic species that in the first step hydrocracking, form, allowed in the second step hydrocracking not too exacting terms.In this regard, only notice that the activity that obtains in 3 ℃ the first step hydrotreatment has significantly reduced the amount of the multinuclear arylide that forms.

Before carrying out the second step hydrocracking, the liquid efflunent of the first step can be handled earlier to remove unwanted gaseous state thing, for example H ₂S and NH ₃Especially to containing a large amount of sulfur-bearings-and nitrogen-compound, the decompression overhead product that obtains by atmospheric residue for example, this intermediate treatment may be highly beneficial.For example, H ₂S can remove by the method that absorbs in amine aqueous solution.In this regard, the diisopropanol amine aqueous solution is very useful.But preferred the selection is by described effluent method through high-pressure stripper before introducing second step is removed H simultaneously from the first step effluent ₂S and NH ₃In this way, the content of these two kinds of undesirable gases in the first step effluent can be reduced to low-down level effectively, is advisable to be lower than 10ppm respectively.This low H ₂S and NH ₃Content allow to use sulphur and nitrogen had higher optionally second step catalyzer, for example (unvulcanized) noble metal-based catalysts.In the second step hydrocracking, use these several catalyzer can produce high quality base oil, for example industrial grade white oil conversely.If the first step is to operate under enough low temperature, then in two step hydrocrackings, use noble metal-based catalysts even can produce medical oil, the latter does not have arylide, nitrogen compound and sulphur compound, thereby prevents to form the multinuclear arylide.

Therefore, if before the first step liquid efflunent is introduced the second step hydrocracking, it is handled to remove H ₂S and NH ₃, then the second step catalyzer should comprise that Pt and/or Pd component are as VIII family metal component.This catalyzer can further comprise a kind of group vib metal component, is preferably based on W or Cr.In this operating method, it may be favourable using identical noble metal-based catalysts in the first step and the second step hydrocracking.On the other hand, if from the first step effluent, do not remove H ₂S and NH ₃, and used charging is not essentially no any sulfur-bearing and/or nitrogen compound, then preferred the use comprises that nickel or cobalt component are as VIII family metal component and molybdenum or the tungsten component second step catalyzer as the group vib metal component.The front has been introduced any suitable example of these catalyzer.

Normally the second step effluent finishes by distilling to reclaim lubricating base oil in step (c).Then, each lubricating base oil reclaims to distillate fraction.Suitable distillation is under reduced pressure carried out.But, also can adopt air distillation.The cut point that distillates fraction should so be selected, so that the base oil that is recovered to has required viscosity.

If the second step catalyzer is not have or almost without any the active hydrogenation catalyst of hydroisomerization, then require postorder dewaxing step (d) to obtain to have the lubricating base oil of enough low pour point.Dewaxing can be adopted catalytic dewaxing or solvent dewaxing.These two kinds of DEWAXING TECHNIQUE all are well-known in the art.For example, the appropriate catalyst that is used for catalytic dewaxing comprises based on ZSM-5, the catalyzer of ZSM-23 or ZSM-35.Suitable dewaxing catalyst and process for dewaxing are for example in United States Patent (USP) 3,700,585; 3,894,938; 4,222,855; 4,229,282; Illustrate in 4,247,388 and 4,975,177.Solvent dewaxing also is known process for dewaxing.The most frequently used solvent dewaxing process is methylethylketone (MEK) solvent dewaxing process, and wherein MEK also can mix use with toluene as dewaxing solvent.For the present invention, preferably use solvent dewaxing process.

If the second step catalyzer is a hydroisomerisation catalysts, then can save step (c) independent dewaxing step afterwards.In the case, the lubricating base oil that step (c) obtains satisfies the requirement of relevant viscosity index and pour point, does not handle so do not need to do in the case depression of pour point.As previously mentioned, the first step effluent with must have enough low sulphur content before hydroisomerisation catalysts contacts.If be used for the hydrocarbon ils of step (a) is hydrogenation wax or synthetic wax raffinate (they generally have low-sulfur and nitrogen content), then can economize and remove H ₂S and NH ₃Intermediate process steps, and the first step effluent can directly feed step (b).On the other hand, if the hydrocarbon ils material of step (a) has quite high sulphur content and nitrogen content, for example under the situation of atmospheric residue underpressure distillation, then require to remove H ₂S and NH ₃Intermediate steps.

In general, adopt the final lubricating base oil that obtains of method of the present invention to have at least 80, preferred at least 90, more preferably at least 95 viscosity index and-6 ℃ or following, preferred-9 ℃ or following pour point.

Below further specify the present invention with embodiment, scope of the present invention is not limited to this specific embodiment.

Embodiment

Contain in existence and to be stated from fluorided alumina carrier (4.4wt.%F, based on total carrier) on 4.3wt.%Pd and 21.9wt.%W (all with respect to the gross weight of catalyzer, in element) the situation of pre-sulfide catalyst under, make by vacuum cleaned atmospheric residue hydrocarbon ils decompression that obtain and that have character shown in Table I overhead product in the first step, to contact with hydrogen.Under the situation that has NiMoP/ aluminium oxide catalyst commonly used (3.2wt.%P is all with respect to the gross weight of catalyzer, in element for 3.0wt.%Ni, 13.0wt.%Mo), in second goes on foot, the effluent of the first step is contacted with hydrogen.The reaction conditions that these two steps are used and be shown in Table II and III respectively in the character of-20 ℃ of common solvent dewaxing back finished products.

Table 1 feed properties

Refractive index, 70 ℃	??1.5010
		Flash-point (℃)	??213
70/4 ℃ of proportion	??0.899
		?Vk80(cSt) *	??28.2
?Vk100(cSt) *	??14.8
		Sulphur (%wt)	??2.68
Nitrogen (%wt)	??0.13
		Hydrogen (%wt)	??12.0
?C 5Bituminous matter (%wt)	??0.08
		Wax content (%wt)	??9.2

* Vk80 and Vk100 represent the kinematic viscosity (centistoke) in 80 ℃ and 100 ℃ mensuration respectively

Comparative example

Repeat above-mentioned same processes, only be to use this moment to contain the 5.0wt.%Ni that is stated from the fluorided alumina carrier (4.6wt.%F is based on total carrier) and the first step catalyzer of 23.1wt.%W.The character of processing condition and the product that obtains in conventional solvent dewaxing (in-20 ℃) back is shown in Table II and Table III respectively.

Table II

Processing condition

Operational condition	Embodiment		Comparative example
					Step 1	Step 2	Step 1	Step 2
	Temperature (℃) WHSV (kg/l.h) gas speed (Nl/kg) pressure (crust)	380 1.0 1500 140	390 1.0 1500 140	400 1.0 1500 140					390 1.0 1500 140

The Table III product characteristics

Productive rate (%wt is based on charging) Vk100 (cSt) VI	Embodiment	Comparative example
			77 9.55 95	72 9.88 93

From Table II and III as can be seen, method of the present invention is used therein in the first step of noble metal-based catalysts and is required lesser temps,, under high yield, still obtain product simultaneously with better VI and viscosity.

Claims (11)

1. prepare the method for lubricating base oil, may further comprise the steps:

(a) the first step in the presence of a kind of catalyzer that comprises at least a VIII family noble metal component that is stated from the refractory oxide carrier, makes the hydrocarbon ils material contact with hydrogen;

(b) in second step, under the hydrocracking condition, in the presence of hydrogenation conversion catalyst, liquid efflunent is contacted with hydrogen; And

(c) at least a viscosity index of recovery is at least 80 lubricating base oil.

2. according to the process of claim 1 wherein that the first step catalyzer comprises that a kind of platinum and/or palladium component are as VIII family noble metal component.

3. according to the method for claim 2, wherein the first step catalyzer further comprises a kind of group vib metal component, preferred tungsten or chromium component.

4. according to the method for aforementioned each claim, wherein the hydrocarbon ils material is the reduced pressure distillate that is obtained by atmospheric residue.

5. according to the method for aforementioned each claim, the hydrogenation conversion catalyst that wherein is used for step (b) is a kind of hydrogenation catalyst of at least a group vib metal component that comprises at least a VIII family's metal component and choose wantonly.

6. according to the method for claim 5, further comprise step (d): the lubricating oil that step (c) is recovered to carries out dewaxing treatment.

7. according to the method for claim 5 or 6, the hydrogenation conversion catalyst that wherein is used for step (b) comprises palladium, platinum or cobalt component as VIII family metal component, and molybdenum or tungsten component are as the VIB component.

8. according to each method of claim 5-7, remove the processing of hydrogen sulfide and ammonia before wherein in step (b), contacting earlier with hydrogen from the liquid efflunent of step (a), the preferred employing makes described effluent pass through high-pressure stripper.

9. according to the method for claim 8, the hydrogenation conversion catalyst that wherein is used for step (b) comprise platinum and/or palladium component as VIII family metal component and, if present, tungsten or chromium component are as the group vib component.

10. according to each method of claim 1-4, remove the processing of hydrogen sulfide and ammonia before wherein in step (b), contacting earlier with hydrogen from the liquid efflunent of step (a), the preferred employing makes described effluent by high-pressure stripper, and the hydrocarbon catalyst that wherein is used for step (b) is a hydroisomerisation catalysts.

11. according to each method of claim 1-3, wherein the hydrocarbon ils material is that the effluent of hydrogenation wax or synthetic wax raffinate and step (a) directly feeds step (b), wherein the catalyzer of hydrocracking is a hydroisomerisation catalysts.