US2097127A - Lubricating oil and method of treating same - Google Patents

Description

Get. 26, 193 7.

R. E. MANLEY LUBRICATING OIL AND METHOD OF TREATING SAME Filed Apr-11 23, 1934 3 Sheets-Sheet 1 Oct. 26, 1937. R-E, MANLEY 2,097,127

` LUBRICATING OIL AND METHOD OF TREATING SAME BY LS ATTORNEY Oct. 26, 1937.

R, E. MANLEY LUBRICATING OIL AND METHOD OF TREATING SAME Filed April 25, 1954 3 Sheets-Sheet 5 Patented Oct. 26, 1937 UNITED STATES PATENT .oEFicE LUBRICATING OIL AND METHOD F TREAT-i ING SALIE Robert E. Manley, Beacon, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application April 23, 1934, Serial No. 721,865

5 Claims. (Cl. 196-17) 'I'his invention relates to the manufacture of It has heretofore been suggested (U. S. patent lubricating oil characterized by a low vpour test, to Davis No. 1,815,022) that a pour point depresand to novel pour point depressants and to methsant for a mineral lubricating oil maybe prepared ods of producing the same, and to the dewaxing by chlorinating paraln wax or similar straight 5 of a wax bearing oil by the employment of such chain hydrocarbons, and thenv condensing the pour point depressants as wax crystal modifying chlorinated wax with an aromatic'hydrocarbon, materials. such as naphthalene, in the presence of a Friedel- -The invention contemplates the preparation of Crafts catalyst. 'I'his has heretofore necessitated mineral lubricating oil having a reduced pour test the selection of comparatively pure or separated and other desired qualities from' lubricating oil organic compounds or products as starting mate- 10 stocks, such as those derived from mixed base and rials; and certain of the aromatic compounds freparafin base crudes and the like, by the addition `qently employed may not ordinarily be available to the lubricating oil of a pour depressing mateat the oil renery. p rial. The invention particularly contemplates the It is an object of the present invention to proaddition to a lubricating oil of the condensation duce a pour point' depressant material of this l5 product in the presence of a Friedel-Crafts character for a mineral oil directly from a readcatalyst, such as aluminum chloride, of a chlor-y ily availableL petroleum oil fraction', and which inated wax bearing lubricating oil, or the conmay not require the previous separation or puridensation product of chlorinated wax and naphilcation .of the ingredients entering the reaction thenic constituents of a wax bearing lubricating to produce the depressant, with resultant mate- 20 oil. The invention also contemplates the preprial economy.

Y aration of a synthetic lubricating oil having a It is a further object of the invention to proviscosity index and other properties simulating vide a synthetic lubricating. oil, and a method those of a Pennsylvania parafnn base type of of producing the same, directly from a wax bearlubricating oil containing a proportion of wax, ing lubricating oil, which has an unusually low 25 whi1e at the same time the pour point of the pour test while at the same time possessing a high synthetic oil is materially below that of a Pennviscosity index.

Sylvania base wax bearing oil. The invention Still another object of the invention is to faalso contemplates the addition to a wax bearing Clitate deWaXillg 0f a WaX bearing Oi'l by utilizaoil of such condensation products to facilitate tiOn 0f the pOur DOint depressants 0f the present 30 dewaxing by mtration, cold settling or centriinvention to modify wax crystal structure upon fuging. v chilling of the oil in the presence of such depres- Lubricating oil stock derived from parailin and SantS- mixed base crudes contains appreciable amounts Other objects and advantages 0f the invention of wax and, therefore, has a relatively high pour will be apparent from the fOllOWing desl'illtlen 35 test unless a substantial amount of this wax is and appended elamS- v removed. The removal of this wax is usually ae- I have discovered that a highly effective pour complished by cold settling, ltration or centripeint depressant material Call be Prepared from fuging. However, lubricating oil stock, after dea wax bearing lubricating'oil fraction by treat- 40 waxing by these processes, may still retain some ing the fraction with chlorine. and then condens- 40 wax. and may have a pour test well above 0 F., ing the chlorinated wax bearing fraetionin the for example, about 25 F. The removal of further presence of a Friedepcraft's catalyst, The requantities of wax from this stock in order to fur- Sultant oily liquid, when separated from the ther reduce the pour test necessitates expensive condensation sludge, is in itself a lubricating oil further processing of low pour test and high viscosity index, and

On the other hand, the presence of a certain amount of Wax in a lubricating ou may be bene can be employed directly for lubricating purposes.

This material, when added to a partially dewaxed flcial from the standpoint of providing a comparatively iiat temperature-viscosity curve,that lubricating ou in a' comparatively Smau proper' is, a high viscosity index. Consequently, it is of tion such ae less than 10% by Weight and fre' 50 advantage to add to a partially dewaxed lubrlcatquently as httle as 1% by Weight 0T less, funcing ou a material which wi11 have the effect of tions es a pour point depressant to materially reducing the pour test or coid test to the desired lower the pour point of the resulting blend. The extent without the necessity of entirely removing material, when added in higher proportions, may` the remaining wax. be used to increase the viscosity index of certain 55 types of lubricating oil having a. comparatively lower viscosity index.

In the accompanying drawings, Fig. 1 is a flow sheet of the method 'of preparing a synthetic lubricating oil and the pour point depressant material, and of the blended wax bearing lubricating oil having lowered pour point, of the present invention;

Fig. .2 is a flow sheet of a modified procedure of preparing the products of this invention; and

Fig. 3 is a flow sheet of a method of dewaxing,

yemploying the products of the present invention.

Referring to Fig. 1, the wax bearing lubricating oil, which may be a paraiiin distillate fraction or a wax bearing residual voil but preferably the former, is passed from a storage tank I0 to a chlorinator II. Chlorine gas from pressure tank I2 is passed through the oil in the chlorinator while the oil is preferably heated to a temperature of about 300 F. for a prolonged period. This chlorinated oil may itself be employed as a lubricant, and for this purpose may be passed from the chlorinator II by line I3 to oil storage tank I4.

Preferably, the chlorinated oil is passed for further treatment by the line I5 to the condensation vat I6. Anhydrous aluminum chloride, which may ormay not have been previously dissolved in alight petroleum distillate fraction such as kerosene, is passed from tank Il to the condensation vat I6. Controlled streams of the aluminum chloride and the chlorinated oil may be added continuously to the condensation vat, which is equipped with a suitable stirrer, while maintaining an elevated condensation temperature. Any other suitable Friedel-Craits catalyst. such for example as halides of zinc, iron, antimony, cadmium, boron, manganese, nickel, tin and the like, can be used, although aluminum chloride is preferred. The reaction may be carried out at room temperature, but under such conditions it takes an appreciably longer time.

The reaction mixture is then passed to a separating tank 2 0, where the aluminous sludge is allowed to settle. The liquid oil or pour point depressant material is drawn off to storage 2I, and the sludge passed to receiving tank 22. The refined oil may be subjected to distillation to remove lower boiling hydrocarbon compounds, and thereby improve the flash and fire tests.

The rened oil may be blended with a partially dewaxed lubricating oil from storage tank 23 in the blending tank 24 in wide proportions. Inasmuch as the refined oil is itself a lubricating oil, it may be used directly as such. Where it is desired to reduce the pour point of a partially dewaxed lubricating oil, a proportion of refined oil generally less than 10% by weight is employed, and often as low as 1% or less. The blended oil is then passed to a finished oil storage tank 25.

As an alternative procedure, the pour point depressant material may be prepared from a wax bearing lubricating oil by iirst separating naphthenic constituents and wax from the oilchlorinatlng the separated wax, and then condensing the chlorinated wax with the separated naphthenic constituents in the presence of a Friedel- Crafts catalyst.

Referring to Fig. 2, in which such an alternative procedure is illustrated, wax bearing oil from storage 30 is passed to a mixing tank 3|, and there mixed with a suitable solvent from tank 32. Any suitable solvent which is highly selective as between naphthenic and parairlnic constituents of the oil may be employed, such for example as furfural, nitroben'zne, dichlorethyl ether, cresylic acid, liquid sulphur dioxide, etc. isi'actory results have been secured employing furfural in the proportions of 3 parts of the solvent to 1 part of oil at a temperature of around F. The solvent mixture is passed to a settling tank 33, where it is allowed to stratify into layers, from which the extract containing the bulk of the furfural with dissolved naphthenic constituents is removed to an extract tank 34, and the ranate containing the bulk of the paraflinic oil and a small proportion of solvent is removed to the raffinate tank 35. The extract is passed to a solvent recovery still 36, where the solvent is distilled from the naphthenic constituents and the latter passed to storage 3l. The raffinate is likewise passed to a solvent recovery still 38; and the solvent free oil then passed through a chiller 39 where the oil is cooled to about 0 F. or below to precipitate the wax. A dewaxing solvent, such as acetone, ethylene dichloride, methyl ethyl ketone, various aliphatic alcohols, and the like, can be employed to facilitate the dewaxing operation. A very satisfactory solvent for this purpose is a mixture of about 35% acetone and 65% benzol for distillate oils, or a mixture of about 28-35% acetone, 47-57% benzol and 15-18% toluol for a residual oil. The chilled mixture is passed to a filter 40, where the wax is separated from the oil, the latter passing to a dewaxed parailinic oil storage 40'. This particular oil is a high grade lubricating oil of high viscosity index, and. may be employed as such. Where a dewaxing solvent is not used, or a higher chilling temperature is employed, which results in leaving a proportion of wax in the oil, the latter may be employed as the partially dewaxed lubricating oil with which the pour point depressant is blended.

The parain wax is removed from the filter 40 to a receiving tank 4I, from where it is passed to a chlorinator 42 and therein treated with chlorine gas from tank 43 in the manner described above. The chlorinated wax is then passed by line 44 to condensation vat 45 to which the naphthenes are also introduced from storage 3l. The proportions in which the chlorinated wax are mixed with the naphthenic constituents may vary widely, such for example as from 1 part to 10 parts of the chlorinated wax to 1 part of the naphthenes. The condensation of the mixture with a Friedel-Crafts catalyst, such as aluminum chloride, from tank 41, is carried out in the manner described above. Following the reaction, the sludge is separated in the separator 48 and passed to receiving tank 49, the rened oil or pour point depressant material being passed to storage 50. This material is blended -in tank 5I with partially dewaxed lubricating oil from storage 52. A portion of the dewaxed paraflinic oil from storage 40 may be passed by line 53 tostorage tank 52 to serve as lubricating oil to be treated. The finished oil is accumulated in storage 54.

'I'he products of the present invention are also useful in connection with the removal of wax from a wax bearing hydrocarbon oil. Thus, the addition to a wax bearing oil of a `small proportion of the condensation product in the presence of a Friedel-Crafts catalyst of a chlorinated wax bearing lubricating oil, or the condensation product in the presence of a Friedel-Crafts catalyst of naphthenes and chlorinated Wax of a wax bearing lubricating oil, is found to modify wax crystal formation upon chilling of the oil, to thereby facilitate separation of the wax from the Very satoil by centrifuging or cold settling. It is also found that the addition of a wax Icrystal modifying material of this character to a wax bearing oil results in substantially increasing filtering rates, where the wax is separated from the chilled oil by filtration. The employment of products of the present invention along with a solvent in which both the normally solid and normally` liquid constituents of a wax bearing oil are' completely insoluble at lowered temperatures of the order of F. to -20`F., is found particu- Various solvents of. this char,-

larly beneficial. acter may be employed, such for example as acetone, ethylene dichloride, methyl ethyl ketone, liquid sulphur dioxide, naphtha, various aliphatic alcohols and the like. Mixtures of a wax solvent and a non-solvent are particularly suitable. For example, a very satisfactory solvent mixture capable of serving as a dewaxing solvent consists of acetone and benzol, for instance in the proportions of 35% acetone and 65% benzol. Another very suitable solvent mixture, particularly for the dewaxing of residual oils, consists of about 2835% acetone, P7-57% benzol and 15-18% toluol. Very satisfactory results are also secured by adding to the wax bearing oil a comminuted filter aid material of the character of infusorial or diatomaceous earth. This is found beneficial when used in conjunction with the wax crystal modifying material and also with a solvent or solvent mixture.

Referring to Fig. 3 of the drawings, a proportion of wax crystal modifying material of the character described above is added from tank 60 to a wax bearing oil in a suitable mixer or agitator 6l. The proportions in which the modifying material can be added to the wax bearing oil vary; but it is found that by increasing the proportion up to a certain amount for a particular oil gives increasingly beneficial effect, while increasing the proportion beyond that amount gives no further benefit and, in fact, may decrease the effectiveness. For example, a proportion of from 1% to %'by weight of the condensation products of the present invention, may be used. A dewaxing solvent from storage tank 62 is also preferably added to the wax bearing oil. By way of` example, a solvent mixture of. 35% acetone and 65% benzol in the proportions of 1 part of oil to 3 parts of acetone-benzol mixture is herein described. The oil mixture is passed through chilling coils 63 where it is chilled to a temperature of around 0 to -10 F. A filter aid material from the hopper feed 64 may be supplied by line 65 to the agitator 6I, so that the oil is chilled in the presence of, the filter aid material. Or, the filter aid material can be supplied by line 66 to the already chilled oil as the latter is fed to a lter 61. Or, a proportion of filter aid can be added both before and after chilling. The lter 61 may be of any suitable conventional construction, such for example as a pressure filter or a continuous filter. The solids including wax are removed by the filter and passed to a receiving vat 68, while the dewaxed oil and solvent pass to a solvent recovery still 69. Here, the solvent is distilled from the dewaxed oil, and is passed to a receiving tank 10 from which it may be returned to the storage tank 62 for reuse in the process.

The dewaxed oil is accumulated in a receiving tank 1I. Where a solvent mixture of the charto have a pour test of around 0 F. when chilled only to about 0 F. or slightly below.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. The method of dewaxing a wax bearing oil, which comprises mixing with the wax bearing oil a small proportion of a material selected from the group consisting of a condensation product in the presence of a Friedel-Crafts catalyst of naphthenes and chlorinated wax of a wax bearing lubricating oil, and a condensation product in the presence of a Friedel-Crafts catalyst of a chlorinated wax bearing oil, said material having the property of modifying wax crystal structure upon chilling a wax bearing oil to precipitate wax in the presence thereof, chilling the mixture to precipitate the wax, and separating the wax from the oil.

2. 'I'he method of dewaxing a wax bearing oil, which comprises mixing with the oil a solvent selective between the normally liquid and normally solid constituents of the oil and in which the normally liquid constituents are soluble at lowered temperatures while the normally solid constituents are substantially insoluble, together with a material selected from the group consistlng of a condensation product in the presence of a Friedel-Crafts catalyst of naphthenes and chlorinated wax ofv a wax bearing lubricating oil,

and a condensation product in the presence of a Friedel-Crafts catalyst of a chlorinated wax4 bearing oil, said material having the property of modifying wax crystal formation upon chilling of the cil to precipitate wax in the presence thereof, chilling the mixture to precipitate the wax, separating the wax from the oil, and recovering the solvent from the dewaxed oil.

3. The method of dewaxing a wax bearing oil, which comprises mixing with the oil a solvent mixture comprising acetone and benzol, together with a material selected from the group consisting of a condensation product in the presence of a Friedel-Crafts catalyst of naphthenes and chlorinated wax of a wax bearing lubricating oil, and a condensation product in the presence of a Friedel-Crafts catalyst of a chlorinated wax bearing oil, said material having the property of modifying wax crystal formation upon chilling of the oil to precipitate wax in the presence thereof, chilling the mixture to precipitate the wax, and separating the wax from the oil.

4. The method of preparing a lubricating oil having a lowered pour test from a wax-containing lubricant fraction, which comprises solvent reflning the lubricant fraction with a solvent which is highly selective as between parafiinic and naphthenic constituents of the oil to separate the oil into a railinate of increased parafiinicity and an extract of increased naphthenic content, dewaxing the raffinate to remove the bulk of the wax from the oil and produce a partially dewaxed oil normally having a pour test above 0 F., chlorinating wax separated in the above mentioned dewaxing step, condensing the chlorinated wax with extract from' the above mentioned solvent refining step in the presence of a Friedel-Crafts catalyst, separating a pour depressant material from the products of condensation, and adding to the partially dewaxed lubrieating oil .a minor proportion of the said pour depressant material to produce a resultant lubricating oil having a pour test of about 0"l F. or below.

5. The method of preparing lubricating oil having a lowered pour test from a wax-containing lubricant fraction, which comprises solvent refining the lubricant fraction with a selective solvent of the character of furfural to separate a ranate of increased paramnicity from an extract of increased naphthenic content. dewaxing the ranate with a solvent of the character of a ketone-benzol mixture to produce a partially

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