US 3663423 A
Description (OCR text may contain errors)
United States Patent 3,663,423 PRODUCTION OF LUBRICATING OILS Robert Neil Bennett, Ashford, Richard Nigel Parker, Middlesex, and Bernard Whiting Burbidge, Surrey, England, assignors to The British Petroleum Company Limited, London, England No Drawing. Filed Mar. 14, 1969, Ser. No. 807,401 Claims priority, application Great Britain, Mar. 22, 1968, 13,889/ 68 Int. Cl. Cg 13/02, 37/02 US. Cl. 208-59 6 Claims ABSTRACT OF THE DISCLOSURE A wholly catalytic route for the production of lubricating oils for petroleum feedstocks boiling above 350 C. comprises the steps of VI improvement over a catalyst of a Group Vla and/ or Group VIII metal on a refractory oxide support and catalytic dewaxing over a catalyst of a Group VIa. and/or Group VIII metal on low alkali metal content mordenite. The steps may be in either order but the VI improvement step is preferably first.
The VI improvement step is at 650-850 F. and 1000-3000 p.s.i.g. using preferably, Co-Mo or silica alumina and the catalytic dewaxing step is at 450-950 F. and 100-3000 p.s.i.g. using, preferably, Pt on decationised mordenite having a SiO :Al O ratio of 14:1-5021. Depending on the feedstock to and the severity of the VI improvement step, lubricating oil product fractions of either high (75-100) or super high (100-140) VI may be produced.
This invention relates to the production of lubricating oils by a wholly catalytic route without the use of solvents.
As conventionally practised the production of lubrieating oils requires the steps of solvent extraction with e.g. furfural to remove aromatics and improve the viscosity index, solvent dewaxing with e.g. an alkyl ketone to remove n-paraffins and improve the pour point and, possibly, a finishing treatment with acid, bauxite or clay to improve colour and colour stability. Hydrocatalytic treatment to replace the acid, bauxite or clay finishing treatment is now well established commercially but although it is acknowledged that solvent extraction of aromatics and solvent dewaxing are expensive and complicated operations, progress at replacing them with hydrocatalytic treatments has been slower. One possible reason for this is that the full economic advantages of hydrocatalytic treatment can only be achieved when satisfactory hydrocatalytic processes have been developed for both stages.
According to the present invention a wholly catalytic process for the production of lubricating oils from a petroleum feedstock boiling above 350 C. without the use of solvents for aromatic and wax removal comprises the steps of passing the oil over a catalyst comprising one or more hydrogenating components selected from Groups VIa and VIII of the Periodic Table on a refractory oxide support together with hydrogen at a temperature of from 650 to 850 F. and a pressure of from 1000 to 3000 p.s.i.g. to give a material of reduced aromatic content and improved viscosity index and also over a catalyst comprising one or more hydrogenating components selected from Groups VIa and VIII of the Periodic Table incorporated with a crystalline mordenite of reduced alkali-metal con tent together with hydrogen at a temperature of from 450 to 950 F. and a pressure of 100 to 3000 p.i.s.g. to give a material of reduced wax content and improved pour point and recovering a lubricating oil fraction of both improved viscosity index and improved pour point.
The steps of viscosity index improvement and catalytic dewaxing may be carried out in either order. Preferably the viscosity index improvement step precedes the catalytic dewaxing step. The abbreviation VI will be used hereinafter to refer to viscosity index.
The feedstock to the process is preferably a vacuum distillate fraction boiling within the range 350-600 C. Since lubricating oils are marketed in several grades with relatively narrow boiling ranges, distillation to give relatively narrow boiling range cuts is required at some stage. In the present invention, a wide boiling range cut may be used as feedstock and distillation into narrower cuts given after the first or second hydrocatalytic treatment or distillation may take place before the hydrocatalytic treatment and individual cuts may be hydrotreated. The former route has the advantage of avoiding blocked operation but the latter route has the advantage that optimum hydrotreating conditions may be chosen for each cut.
Within the context of hydrocatalytic treatment for VI improvement, two general processes are recognised. These are (i) a relatively mild treatment to give a moderate VI improvement e.g. to 100 VI after dewaxing with minimum breakdown and decrease in viscosity. Increase in VI of the product to bring it up to multi grade oil requirements, if desired, can be achieved by the use of known polymeric VI improvers. (ii) a more severe treatment with extensive breakdown and decrease in viscosity but giving a larger VI improvement e.g. greater than 100 VI after dewaxing. A larger amount of lower boiling gas oil, kerosene and gasoline by-products are obtained with the more severe treatment.
Preferably the milder type (i) process is used with a distillate feedstock boiling in the range 350-600 C. having a VI of 30 to and with a breakdown to products boiling below 350 C. of less than 30 percent wt. under the following ranges of conditions:
Temperature, F. 650-850 Pressure, psig 1000-3000 Space velocity, v./v./hr. 0.1-5
Hydrogen treating rate, s.c.f./b. 2000-10,000
If the VI improvement step precedes the catalytic dewaxing step the VI of the product boiling above 350 C. should be in the range 90-120 to allow for some reduction in VI in the subsequent catalytic dewaxing step. If it follows the catalytic dewaxing step this dewaxinsg step will already have lowered the VI of the original feedstock, and the VI of the. product boiling above 350 C. from the VI improvement step should be from 75 to 100.
The refractory inorganic oxide support may be one or more oxides of elements of Groups II, III or IV of the Periodic Table, and may contain halogen. Preferably the amounts of the components of the support are chosen from the following ranges:
Percent wt. A1 0 50-100 Si0 0-50 B 0 0-25 F or Cl 0-10 Percent wt. (expressed as metal) Group VIa metals 2-25 Iron group metals 1-15 Platinum group metals 0.1-5
Preferred hydrogenating components are from 2-25 percent wt. of molybdenum (expressed as metal but present as oxide or sulphide) and 1-15 percent wt. of nickel and/or cobalt again expressed as metal but present as oxide or sulphide.
With the more severe type of VI improvement process the preferred feedstocks boil with the range 450-600 C. and have a VI of 30-90. The following ranges of condi tions may be used to give a conversion to products boiling below 350 C. of 30-80 percent wt.
Temperature, F. 725-850 Pressure, p.s.i.g 1000-3000 Space velocity, v./v./ hr 0.1-5 Hydrogen treating rate, s.c.f./b. 2000-10,000
If the VI improvement step precedes the catalytic dewaxin'g step the VI of the product boiling above 350 C. should be in the range 120-160 to allow for some reduction on VI in the subsequent catalytic dewaxing step. 'If it follows the catalytic dewaxing step, this dewaxing step will already have lowered the VI of the original feedstock and the VI of the product boiling above 350 C. from the VI improvement step should be from 100 to 140.
The catalyst is preferably the same as for the milder type (i) process both in terms of the hydrogenating component and the support. The support may, however, be more acidic than the preferred support of the milder process and may consist for example of 60-90 percent wt. Si and 10-40 percent wt. A1 0 or 85-90 percent Wt. A1 0 and 5-15 percent wt. halogen.
It will be appreciated that the acidity of the catalyst support, the temperature, pressure and space velocity all affect the severity of the operation and hence the degree of VI increase and viscosity decrease obtained and that any one or more of these may be varied as required. Preferably the space velocity is lower for the more severe type (ii) process than for the milder type (i) process.
The term VI as used in this specification means viscosity index as measured by ASTM D567. Currently two methods are in use ASTM Test Method D567 and the VIE extended method ASTM D2270. Appreciable differences in numbers are possible between the two methods when testing the same oil.
In addition to VI improvement, sulphur and nitrogen in the feedstock will be converted, if present, to H 8 and NH The latter is desirably removed (by scrubbing with water) from any gas recycled and both H 8 and NH are desirably removed from any gas passing to the hydrocatalytic dewaxing stage.
The catalytic dewaxin'g step operates selectively to break down the paraifinic waxes to lower boiling materials which are readily removable from the remainder of the lubricating oil feedstock, which remains substantially unaffected. It may follow the general procedure described in UK. patent specifications Nos. 1,088,933; 1,134,014 and 1,134,015. The term paraflinic wax refers to those waxy hydrocarbons which have a long straight chain as part of their structure, e.g. particularly n-paraffins themselves but also very slightly branched chain hydrocarbons, and cyclic hydrocarbons having an unbranched alkyl side-chain. The selective breakdown of the paratfin wax hydrocarbons is due to the nature of the mordenite based catalyst which promotes the selective attack of these hydrocarbons but not of the other hydrocarbons present in the feedstock.
Suitable process conditions for the catalytic dewaxing include besides a temperature within the range 450-950 F. and a pressure within the range 100-3 000 p.s.i.g. as indicated above, a space velocit between 0.1-20.0 v./v./hr., and a gas rate of SOD-30,000 s.c.f. of hydrogen.
Preferred catalytic dewaxing conditions are:
Temperature, F. 500-800 Space velocity, v./v./hr. (LS-10,0 Pressure, p.s.i.g 500-3000 Hydrogen treating, s.c.f./b. 5000-15,000
The term crystalline mordenite of reduced alkali metal conten means, preferably, a mordenite with an alkali metal content of less than 3 percent wt. The deficiency of alkali metal cations can be made up with other metal cations for example Group II metal cations, particularly magnesium or rare earth metal cations. Preferably however the mordenite is a decationised mordenite which means a mordenite having a deficiency of metal cations. An alternative term in the art is hydrogen mordenite, since it is assumed that when metal cations are removed they are replaced by hydrogen ions. However, since it is not possible to detect the presence of hydrogen ions in zeolites, the precise structure remains in doubt. A cation deficiency can, on the other hand, be readily measured by analysis of the metallic elements present in the zeolite.
Natural or freshly prepared synthetic mordenite has the formula:
where Me is a metal cation, m is the valency of the cation and X is variable between nil and 7 depending on the thermal history of the sample. Me is commonly sodium and in one common form of decationisation sodium mordenite is base exchanged with ammonium cations. The ammonium form is then heated to drive off ammonia, leaving behind the hydrogen form or decationised mordenite. According to the second method the mordenite may be treated with a mineral acid, for example hydrochloric or sulphuric acid, in order directly to decationise the mordenite. A combination of acid treatment and am monium treatment can also be used.
Preferably the decationised mordenite used in the present invention has a higher than normal silicazalumina ratio of at least 14:1. In specific examples ratios of as high as :1 have been obtained and a practical upper limit may thus be :1. Particularly preferred silicazalumina ratios are in the range 14:1 to 50:1.
It has been found that certain decationisation treatments remove aluminium as Well as the expected metal cations and desirably therefore the mordenite used in the present invention having a higher than normal silicazalumina ratio is obtained by treatment of a metal cationcontaining mordenite, particularly sodium mordenite, with a strong acid, for example sulphuric or hydrochloric acid, of from 5-50 percent wt. strength and preferably from 10 to 20 percent wt. strength. A single treatment or two or more successive treatments may be given with acids of the strengths stated above.
A convenient method of treatment is to treat the mordenite with acid under reflux for a period of 2-12 hours.
In the decationised mordenite the residual metal cation content, for example the sodium cation content, should be less than 2 percent wt. of the mordenite and preferably less than 1.5 percent wt. of the mordenite.
It should be emphasised that mordenites with higher than normal silicazalumina ratios retain the crystal structure of mordenite and are not significantly altered in terms of physical strength, stability or crystallinity.
The hydrogenating component is preferably a platinum group metal, particularly platinum or palladium, and it is preferably added by ion-exchange. Preferably the mordenite is aged in water before adding the platinum group metal as described in the specification of UK. application No. 4421/ 6-8, which application corresponds to US. patent application Ser. No. 790,829, filed Jan. 13, 1969 and now Pat. 3,553,103. The amount of the platinum group metal is preferably within the range 0.01 to 10 percent Wt., particularly 0.1 to 5 percent wt. However, iron group metals, particularly nickel, also give useful results and they may be used in amounts similar to the platinum group metals. Mixtures of certain Group VI and VIII metals and compounds may also be used, e. g. cobalt and molybdenum.
The catalyst is preferably calcined at for example 250- 600 C. before use to remove any water and to eliminate any ligands attached to the hydrogenation component.
The catalytic dewaxing step is capable of treating lubricating oil fractions with pour points of from 60 to 120 F. to give products of from +40 to 60 F. Some reduction of VI is to be expected since n-paraffins are materials of high VI.
The lubricating oil product from the dewaxing stage is stabilised to remove the breakdown products, which consist largely of C and C paraflins, which are valuable for use in LPG and as petrochemical feedstocks. There may be a small amount of C -C hydrocarbons produced, but it is a particular feature of the catalyst of the present invention that it does not give large amounts of C hydrocarbons in the gasoline and middle distillate boiling ranges and is not a hydrocracking catalyst as generally understood.
As stated above, lubricating oils are usually given a finishing treatment to improve colour and colour stability which is now usually a mild hydrocatalytic treatment known as hydrofinishing. It has been found that the catalytic dewaxing process used in the present invention itself affects improvement in colour and colour stability so that it may be possible to dispense with a finishing step altogether.
The invention is illustrated by the following examples.
EXAMPLE 1 A Kuwait wax distillate having a 2% TBP point of 350 C. and an end point of 560 C. and having the inspection data shown in Table 1 below was hydrogenated material beoling below 240 C. had the following inspection data:
Yield of product boiling above 371 C., percent wt. 74.1
Kinematic viscosity at 100 F., cs 22.3 Kinematic viscosity at 210 F., cs. 4.29 Viscosity index 111 Four point, F 90 Sulphur content, percent wt 0.06 Wax content, percent wt. 13.8 Wax melting point, F. 124
The topped product was then passed to a catalytic dewaxing stage using a platinum-decationised mordenite catalyst having the following composition (calculated on material stable at 550 C.) Platinum perce'nt wt 0.62 Aluminium do 5.08 Silicon do 40.3 Sodium do 0.93 SiO :Al O mol ratio 15.3 Surface area m /g 425 Pore volume ml./g 0.22
The space velocity and gas rate were varied during the run to assess the effect of these variables. Temperature and pressure were kept constant. After the catalytic de- Waxing the product was distilled to remove material boiling below 371 C. and the material boiling above 371 C. was vacuum distilled to give 6 fractions. The process conditions used, the yields obtained and inspecunder the conditions shown in Table l. tion data on the 6 fractions are given in Table 2 below.
TABLE 2 Conditions for catalytic dewaxing' Pressure, p.s.i.g 1, 000 Temperature, F-.. 700
Space velocity, v.lv./h 2. 0 4, Gas rate s.e.f./bb1 10,000 5,000 Inspection ata on dewaxed liquid product:
Pour point, F -40 Average yield on feed, percent wt. 71. 0 75. 0 Yield of residue 371 C. on feed,
percent wt 52. 0 50, 8
Yield on Yield Yield on Yield residue, on feed, Pour residue, on feed, Pour percent percent KV,100 KV, 210 point, percent percent KV, 100 KV, 210 point., wt. wt. F., est. F., est. VI F. wt. wt. F., est. F., est. VI F. Inspection data on fractions ex residue i 1 17 1 s 9 a0 a9 4 3 rec on 9 2 55 17.1 8.7 85.51 4. Fraction 2- 16.9 8.8 36. 97 4.97 42 -45 16.8 8.5 40.39 5. 2 53 i3 Fraction 3- 17.8 9.3 44.90 5.72 63 -40 16.9 8.6 46.91 5.96 69 -15 Fraction 4--- 15.9 8.3 57.83 6. 84 74 -25 16.7 8.5 57.49 6.95 80 0 Fraction 5--- 16.3 8.4 71.37 8.19 89 0 16.7 8.5 69.73 8.07 89 15 Fraetionfi (residue)- 16.0 8.3 118.4 11.85 96 25 15.8 8.0 108.8 11.35 99 30 TABLE 1 Inspection data on feed; Fractions 5 and 6 of Table 2 are products of increased Kinematic viscosity VI and improved pour points according to the invention. 100 F., cst. 75.00 Fra tions '1-4 which have improved pour points but not 210 F., cst 7.92 increased VI are particularly suitable for use as very low VISCOSItXIBdEX 73-00 pour point industrial oils -*(e.g. transformer oils). Pour point, F. 95 Sulphur content, percent wt. 2.76 EXAMPLE 2 Nitrogen content, percent wt. 0.10 Wax q f p Wt A Kuwait wax distillate fraction having the inspection Hydrogenation conditions employed:
Catalyst (1) data shown in Table 3 below was hydrogenated under Pressure, psig 1500 the conditions shown in Table 3. Temperature, F. 770 Space velocity, v./v./h. 1.5 T B E 3 Recycle gas rate, s.c.f./bbl. 7500 Recycle gas Scrubbing 2 Inspection data on feed: Hydrogen consumption, s.c.f./bbl 750 Kinematlc vlscoslty O Cove/silica alumina. Catalyst composition was: F" 4017 I0 labd percent WE. 210 F., 68- 5-'6 1 0 y 61111111 percen W iilicon 9.0 percent wt. Vlscoslty Index 82 lumina Balance. e Surface are 331 mF/g. Pour polnt F' 85 "A For ,5 extrudates. Sulphur content, percent wt. 2.42 a remov :Nitrogen content, percent wt. 0.08 The product from this stage after topping to remove Wax content, percent wt. 12.6
Hydrogenation conditions employed:
CoMo/SiAl (as in Example 1).
2 Ammonia removal.
The total liquid product from this hydrogenation step was then stripped of H 8 and passed to a catalytic dewaxing stage using platinum-decationized mordenite (as Periodic Table incorporated with a crystalline decationised mordenite having a sodium content of less than 2 percent wt., said mordenite having a SiO :Al O ratio of from 14:1 to 50:1, at a temperature of from 450 to 950 F., a pressure of 100 to 3000 p.s.i.g., a space velocity of 01-200 v./v./hr. and a hydrogen treating rate of 500- 30,000 s.c.f./b. at which there is produced a material of reduced wax content boiling above 350 C. and having a reduced pour point and an improved viscosity index of from 75 to 140; and recovering a fraction having an improved viscosity index of at least 7 points higher than that of the original feedstock and a pour point of at least below 15 F.
2. A process as claimed in claim 1 wherein the feedin Example 1) a h dewaxjng catalyst, 15 stock is a vacuum distillate fraction boiling within the After the catalytic dewaxing step the product was dis- 'f hawng VI P 30 t0 90 d h tilled to remove material boiling below 371 C., and the vlswslty Index lmproverrient p 15 carried out at material boiling above 371 C. was vacuum distilled to 1000-3000 P- and 0'- give 5 fr ti n 10,000 s.c.f./b. to a conversion of less than 30 percent The dewaxing conditions used, the yields obtained and 20 of P u bollmg below 350 C the inspection data on the 5 fractions are given in Table Process as cliflllled 111 clalfll 1 l feed- 4 b l stock is a vacuum dlstillate fraction boiling within the TABLE 4 etreatsstarters: 1.
Temperature, F 700 700 Space velocity, v./v./h 4. 0 6.0 Gas rate, s.c.t.fbbl 10, 000 Liquid yield on dewaxing 73. 3 75 Ingple eton data on dewaxed liquid product Ponr polnt, F Yield of residue 371 C. on feed, percent weight 47. 4 0
m Yield on 33 453 original Yield wax Yield wax on distillate on distillate residue, feedstock, KV, KV, Pour residue, feedstock, KV, KV, Pour percent percent 100, 210, point, percent percent 100, 210, point, wt. w cs. cs. F. wt. wt es. cs. VI
20.9 9.6 23.81 3.97 44 -50 22.1 10.9 29.04 4.69 79 -1o Fraction 2-- 20.1 9.45 27. 00 4.4 64. -35 22.3 11.1 30.98 4.96 90 5 Fraction 3-. 20.3 9.3 30. 56 4. 79 76 -30 23.5 11.6 32.91 5.21 96 15 Fraction4 19.9 0.1 36.88 5.48 90 -10 21.1 10.4 36.98 5.70 103 20 Fractionli (residu 18.2 5.4 57.81 7.47 99 5 10.8 5.2 58.08 7.83 100 Again it will be seen that fractions of high VI and low range 450-600 C. having a VI of 30 o 90 and the vispour point are obtained. From the fractions on the right cosity index improvement step is carried out at 725-850 hand side of the table, 32.5 percent wt. (based on the R, 1000-3000 p.s.i.g., 0.1-5 v./v./hr. and 2000l0,000
original wax distillate feedstock) of a lubricating oil of s.c.f./ b. to a conversion of 30 to 80 percent wt. of prod- 5.4 cs. viscosity, 100 VI and 15 F. pour point can be ucts boiling below 350 C.
obtained, which (apart from a marginally high pour 4. A process as claimed in claim 1 wherein the vispoint) is within the specification for 65/ 1000 grade lubricosity index improvement step catalyst comprises from eating oil. 2-25 percent wt. of molybdenum and 1-15 percent wt.
We claim: of nickel and/ or cobalt on an alurninazsilica support hav- 1. A wholly catalytic process for the production from ing from 50-90 percent wt. of alumina and 10-50 percent a wax-containing petroleum feedstock boiling in the wt. of silica.
range 350-600" C. and having a viscosity index of from 5. A process as claimed in claim 1 wherein the catalytic 30 to 90, of an improved lubricating oil boiling above dewaxing step is carried out at 500-800" F., 500-3000 350 C. and having a reduced pour point and an imp.s.i.g., 0.5-10 v./v./hr. and 5000-15000 s.c.f./b. using proved viscosity index of from 75 to 140, in the absence a catalyst comprising from 0.01-10 percent wt. of a of any solvent refining for the removal of aromatics and P m gr p metal iHCOTPOIated with the crystalline wax from the feedstock, said process comprising the Steps decationised mordenite having a sodium cation content of passing the feedstock, together with the hydrogen, of less than 2percent wt.
over a viscosity index improvement catalyst comprising 6. A wholly catalytic process for the production of an one or more hydrogenating components selected from improved lubricating oil boiling above 350 C. and having Groups VIa and VIII of the Periodic Table, on a refraca reduced pour point and an improved viscosity index of tory oxide support, at a temperature of from 650' to 850 from 75 to 140, from a wax-containing petroleum feed- R, a pressure of from 1000 to 3000 p.s.i.g., a space stock boiling in the range 350-600 C. and having a visvelocity of 0.1-5 v./v./hr. and a hydrogen treating rate cosity index of from 30 to 90, in the absence of any of 2000-l0,000 s.c.f./b. at which there is produced a solvent refining of the feedstock for the removal of material of reduced aromatic content boiling above 350 aromatics and wax from the feedstock, said process com- C. and having an improved viscosity index of from 90- prising the steps of passing said feedstock, together with 160, thereafter passing said material of improved visthe hydrogen, over a dewaxing catalyst comprising one cosity index, together with hydrogen, over a dewaxing or more hydrogenating components selected from Groups catalyst comprising one or more hydrogenating coin- Vla and VIII of the Periodic Table incorporated with a ponents selected from Groups VIa and VIII of the crystalline decationised mordenite having a sodium content of less than 2 percent wt., said mordenite having a Si :Al- O ratio of from 14:1 to 50:1, at a temperature of from 450 to 950 F., a pressure of 100 to 3000 p.s.i.g., a space velocity of 01-200 v./v./hr. and a hydrogen treating rate of 50030,000 s.c.f./b., at which there is produced a material of reduced wax content boiling above 350 C. and having a reduced pour point, thereafter passing the feedstock having a reduced pour point, together with hydrogen, over a viscosity index improvement catalyst comprising one or more hydrogenating components selected from Groups VIa and VIII of the Periodic Table, on a refractory oxide support, at a temperature of from 650 to 850 F., a pressure of from 1000 to 3000 p.s.i.g., a space velocity of 0.1 v./v./hr. and a hydrogen treating rate of 2000-10,000 s.c.f./b., at which there is provided a material of reduced aromatic References Cited UNITED STATES PATENTS 2/1968 Reid 208-- 7/ 1968 Gladrow et al. 208-111 HERBERT LEVINE, Primary Examiner US. Cl. X.R.
208-18, 111, DIG. 2
UNITED Y STATES IPIATENTIA OFFICE I I CERTIFICATE ()ECORRECTION Petent No. v3,663,423 5 Dted May "16, 197 2 In 'entofls) Robert Neil Bennett, Richard Nigel Parker'en'd Bernard Whiting Burbidge v I v It; is certified that; ferr'orappears in the above-identified patent "and that said LettersPatent arehe-reby Corrected as shown below:
Col. 7, Table r, v right-hand column headed "Pour, Point 31 o' I I for "-70" read -v-- 1.0 v
Col. 8, Line 45, I i for "30 0 90"] I read signed endesealed thiSfSth -deyi of' Deoembe'r- L), Attestt EDWARD'MQFLETCI-IERJR. ROBERT GOTTSCHALK f Attesting Officer I Commissioner of Patents FORM PO-1 (10-69) v r r f USCbMM-DC scam-p65 e u.s. eoyennmm PRINTINGOFFICE: i959 0-386-334