US2111831A - Production of improved lubricating - Google Patents

Description

March 22 1938.

H. R. BATCHELDER ET AL v PRODUCTION OF IMPROVED LUBRICATING OILS Filed Aug. 24, 1932 INVENTQRS BMIQI.

ATTORNEY Patented Mar. 22, 1938 2,111,831 raonuc'rron or mg' ngvnn LUBRIOATING Howard It. Batchelder, Hammond, and Ward E. Kuentzel,

Whiting, Ind.,

assignors to Standard Oil Company, Chicago, 111-, a corporation of Indiana Application August 24,- 1932, Serial N0. 630,252

9 Claims. -(c1. 196-10) Our process relates to the production of improved lubricating oils by the high pressure polymeraation of gaseous oleflns.

It is well known that gaseous olefins may be polymerized at elevated temperatures and pressures to yield liquids ranging from gasoline-type products to extremely high boiling and viscous oils, depending on the temperatures, pressures and catalysts used. Previous investigators have, 10 however, reported that lubricating oils produced by such methods have highly undesirable characteristics, in particular displaying very undesirable temperature-viscosity relationships. The temperature viscosity characteristics of lubricating oils are best compared and defined by the so-called Dean and Davis Viscosity Index (see Dean and Davis, Chem. Met. Eng. Vol. 36, page 618, 1929) (abbreviated herein as V. I.) According to this criterion, the higher the V. I. the

less the change of the viscosity of the oil withchange in temperature, a low rate of such change (i. e. a high V. I.) being a highly desirable characteristic of lubricating oils. The highest V. I. found among oils derived by distillation from naturally occurring crude oils is approximately 100, while the V. I. of lubricating oils from low grade crude oils is in the vicinity of 20.

Previous investigators of the polymerization of olefin gases have reported very poor results as regards the V. I. of the products. For example, Sullivan (Industrial and Engineering Chemistry, Vol. 23, page 604, 1931,) reports the oils obtained by polymerization of ethylene to be -150 V. I.

, Similarly Nash (J. Inst. Pet. Tech. Vol. 16, page 838, 1930) reports-viscosity-temperature data for lubricating oils produced by this method, which in our present terms of viscosity index correspond respectively to -5 V. I. and 47 V. 1. Furthermore, Nash states thatv the viscosities of these oils fall oflf more rapidly with rise in temperature than is the case with commercial lubricating oils of similar viscosity. Obviously, all of these products are much worse than even low grade oils from natural sources.

We have discovered that by suitable adjustment and careful regulation of conditions of time, temperature and pressure, and by the avoidance of the presence of active catalytic substances, we

can obtain oils having higher V. I. than naturally occurring oils from any source of oils which are worse than most naturally occurring oils from this standpoint- The following table shows the character of the product which we obtain at 3,000 pounds pressure and at the temperatures shown, using a regulated time of contact. 5

Table I Viscosity at Dean 6: Davis Tempm 210F Sa ybolt Viscosity tum (Univ.) secs. Index 10 Overhead distillates, this being necessary on account of some tar formation in these runs.

v(Berichte Deut. Chem. Ges. Vol. 44, page 2978, 30

1911) found that 240 minutes was required. The use of such excessive times of contact apparently leads to undesired side reactions or reconversions. By careful control of our operating conditions and by operating within a limited range'of tem- 35 peratures and pressures in a continuous system, as elsewhere described herein, we find that entirely diflerent results from those previously reported are obtained Operation in a continuous system is also necessary to obtain the uniform 40 conditions-necessary to our process.

The variation in results with changes in the Various operating conditions of this process is shown in the following tables.

Polymerizing ethylene in the absence of a 4 catalyst at 3000 lbs/sq. in. pressure-and 650 F. for various times of contact, the results are as follows: (In these tables the term percent bottoms refers to the percent of material in the product boiling above the gasoline boiling range, 50

which is indicative of the content of heavy lubricating oils.)

Table II light and Percent bottoms Percent Time (minutes) converslon o'clo- Operating at 3000 pounds pressure and 700 F. the results are as follows:

Table III I Time Percent Percent (minutes) conversion bottoms Operating at 3000 pounds pressureand 750 F. the results are as follows:

Table IV Time Percent Percent (minutes) conversion bottoms of 650-750 at 3000 pounds per square inch pressureand preferably in the rangeof 675-725",

using time of Contact of 5-100 minutes if high operated at as high pressure as possible consistent quality lubricating oils are to be obtained in good yields. In general, at the lower temperature of our preferred-range, we use the longer time of contact, and vice versa. Ordinarily we prefer to operate under such conditions of time-temperature-pressure as to give between 30%-75% and preferably 40%-60% conversion of olefins to total liquids per passsince this gives the maximum yield of the desired high-quality products (on account of the fact that longer time. and higher'conversions cause degradation of the product first produced). The time of contact necessary for'the 30-75% conversion at 3000 pounds pressures is about 60-100 minutes at.650 F., 20-70 minutes at 700'? F., and 5-20 minutes at 750 F. For the preferred conversion range of 40-60% the time of contact will be approximately minutes at 650 F., approximately 30 minutes at 700 F., and approximately 10 minutes at 750 1''. In other words at a'temperature of t (F.) within the temperature range of 650-750 F. and at 3000 lbs. pressure the optimum time 'of contact (T) minutes may be expressed by the approximate formula 50 log T=50+(750-t) log 3 this value applying to relatively pure olefin gases within limits of :10%.

To show the great eiIect of pressure on the results, the data of the following Table V may be noted, showing experiments carried out at F. with 7 minutes time of contact.

It is necessary to use pressures of at least 2000 pounds and preferably of at least 3000 pounds to obtain good yields of high quality lubricating oils, and we find that still higher pressures give still further improved results. Pressures of 5000-10,000 pounds per square inch may be used advantageously. With higher pressures, low temperatures may be employed. For example, at pressures in the range of 3000-5000 pounds, we may use temperatures of GOO-700 F., while at pressures of 10,000 pounds, we may use temperatures as low as 500 F. At higher pressures considerably shorter times of contact may be used at a given temperature. By doubling the pressure, similar yields of liquid products may be obtained in from 50-75% of the time of contact at the lower pressure.

The apparatus for carrying out our improved process and the actual operation thereof is very simple and the drawing attached hereto and which forms part of this specification represents a diagrammatic elevational view of suitable apparatus for our process.

Referring to the drawing gases containing at least 50% 'by volume of gaseous olefins are introduced through line In and are compressed by compressor II to pressures of 2500-10,000 pounds per sq. in. following which they are passed through heater l2, wherein they are heated to temperatures of 500-750 F. prior to their introduction into unheated reaction drum ll.

Fromdrum l3 theproducts pass through line H to cooler l5, following which they pass through valve l5a into separator l6, which ordinarily is with proper phase separation of liquids and gases (this is usually not over 2000 pounds per'square 'inch) and from which gases may be vented through ofitake I! or recycled through line ll by booster l9 to the inlet of heater l2. Liquids anddissolved'gases are withdrawn from separatorl6 through oiItake 20, the pressure reduced by valve 2| and the final liquid products separated. from dissolved gases in separator 22. Gases removed in 22 may be eliminated from the systemthrough line 23 or may be recycled through line 24 to the gas supply line l0 leading to compressor Ii. Liquid products from separator 22 may bereheated and fractionated in tower 25 (which is provided with heating and fractionatingmeans not shown) and all or a part of the light and intermediate liquid products which are removed as vapor from bubble tower 25, condensed in cooler 26 may be drawn off thru 260 or may be recycled by pump 21 thru line 21a to the inlet of heater l2, whereby the ultimate yield of higher boiling liquid products suitable for lubricating oils may be increased. Desired heavy lubricating stocks are drawn from tower 25 thru ofitake 28. The final heavy lubricating stocks may be redistilled to eliminate small proportions of tarry or asphaltic constituents, and/or may be'treated with acid, clay, or other conventional lubricant refining methods. A It will also be understood that separators l6 and 22 may be supplied with bubble plates, baflles, heating and cooling coils and other conventional means for improving separation therein.

The foregoing being a full and complete description of our invention,

We claim:

1. A process for the productionof lubricating oils having a viscosity index of at least 100 by a polymerization process wherein the lubricating oil produced by the process comprises a substantial proportion of thetotal normally liquid products, which comprises subjecting gaseous olefins in the absence of active catalysts to a temperature t F.) in the range GEO-750 F. while under a pressure of approximately 3000 pounds per square inch for a time T (minutes) substantially as defined by the relationship 50 log T=50+ (750-t) 10g 3 2. A process for the production of high viscosity index lubricating oils which comprises subjecting-normally gaseous olefins in the absence of active catalysts to a temperature of about 675-725 F. under a pressure of about 3000 pounds per square inch for a time as defined by the following formula:

5010g T=50+ (750-4) 10g 3 where T is time in minutes and t is temperature in degrees F. I

3. A process for the production of high vis-' cosity index lubricating oils which comprises subjecting normally gaseous olefins in the absence of active catalysts to a temperature of about 500-750 F. under a pressure of about 2500-10,000 pounds per sq. in. for a time within about i10% of that defined by the following formula:

50 l0g T=50+ (750-13) log 3 I where T is time in minutes and t is temperature in degrees F. I

4.- A process as defined in claim 3 which also comprises fractionating liquid products produced by the polymerization step into heavy liquids and light liquids, recycling light liquids and treating said light liquids in the reaction system in admixture with normally gaseous olefins as defined in claim 3.

5. A process as defined in claim 1 which also comprises fractionating liquid products produced by the polymerization step into heavy liquids and light liquids, recycling light liquids and treating said light liquids in the reaction system in admixture with normally gaseous olefins as defined'in claim 1.

6. A process as defined in claim 2 which also comprises fractionating liquid products produced 4 the following formula;

50 log T=50+(750-t) 10g 3 where T is time in minutes and t is temperature in degrees F.

8. A' process for the production of high viscosity index lubricating oils which comprises subjecting a gas consisting mostly of ethylene in the absence of active catalysts to a temperature within the range of 650-750 F. under a pressure within the range of 2000-3000 lbs. per square inch for a. time within about :L10% of that defined by the following formula:

50 log T=50+ (750t) 10g 3 where T is time in minutes and t is temperature in degrees F.

9. In a process for the production of high viscosity index lubricating oils, the steps comprising subjecting normally gaseous hydrocarbons consisting mostly of ethylene, in the absence of active catalysts, to a temperature of from 500-750 F. under pressures of 2,500 to 10,000 pounds per square inch for a time within of that defined by the following formula:

- 50 16g T=50+(750-t) log a where T is time in minutes'and t is temperature in degrees F.

HOWARD R. BATCHELDER. WARD E,

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