US1924879A - Oil distillation apparatus - Google Patents

Description

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A115139, 1933. A. E. PEW, JR

OIL DISTILLATION APPARATUS Original Filed April 4, 1929 Patented Aug, 29, 1933 sA'r sur orties OIL DISTILLATIQN APPARATUS Arthur E. Pew, Jr., Bryn Mawr, Pa., assigner to Sun Oil Company, Philadelphia, Pa., a corporation of New Jersey Original application April 4, 1929, Serial No. 352,392. Divided and this application August 6, 1931. Serial No. 555,391

6 Claims. (Cl. 196-119) In a patent issued to me September 27, 1932, No. 1,879,948, of which this application' is a division, I have set forth a process and apparatus for producing lubricating oil distillates of diiferent boiling points wherein the heat required for effecting distillation, at least of a number of the higher boiling fractions, is supplied by the condensation of mercury Vapor generated in a plurality of mercury boilers. The construction and arrangement whereby these boilers are connected with a series of stills are not therein claimed and form the subject matter of this application.

The present invention may be fully disclosed by a description of that part of the apparatus which is in operative relation with the mercury boilers and which is shown in diagram in the single gure oi the drawing.

In the said apparatus gasoline, kerosene, gas oil and lighter lubricating oil fractions may be distilled in an apparatus forming no part of the present invention. For example, the lubricating oil fractions distilled in such apparatus may comprehend lubricating oils or" 100, 200, and G at 100 F. viscosity. v

The residual oil from these preliminary distillations may be, however, so iar as concerns the present invention, oil from which any desired fractions have been distilled. It is pumped through a line 4i) and through a pipe coil 4l in a heating chamber 7G. The heatinI medium in this chamber is, preferably, mercury Vapor, but other heating media may be substituted, particularly substances such, possibly, as diphenyl oxide, benzo phenone, sulfur, or perhaps a suitableV metal alloy, as may be found to possess those characteristics oi mercury vapor that make it especially advantageous in the distihation of the higher boiling lubricating oils. It will be understood, therefore, that, hereinafter, when mercury boilers are referred to, the term is intended to include boilers adapted to vaporize materials which are in a broad sense, equivalent to mercury.

In chamber the mercury vapor condenses and imparts its latent heat to the oil flowing through coil 41. The mercury vapor is generated in a mercury boiler 7l from which extends a mercury vapor pipe line 72 to chamber 70. Pipe 72 is equipped with a valve 73, by means oi which the rate or" iiow oi the mercury vapor into chamber 70, and thereby the pressure and temperature of condensation within the saine and the heat to which the oil is subjected may be accurately regulated. This temperature oi condensation should be such that there will be a comparatively low' temperature dierence between theoil flowing through coil 4l and the surrounding mercury vapor as measured by the logarithmic mean temperature difference at'the inlet and the outlet of the coil. 60

Extending from chamber 70 is a mercury condensate return, which comprises a clean out cup 74, goose-neck 75, pipe 76 and chamber 77 cornrnunicating with boiler 71. .The connections shown are adapted not only to allow mercury condensate to return to boiler 71, but also to provide balancing columns oi liquid mercury '(in goose-neck; to take care of pressure diierences between boiler 71 and chamber 70.

In coil 4l the oil is heated to the 'desired temperature, say 625 F., and suiiicient latent heat is applied to Vaporize the desired fraction within the coil; or, alternatively, the pressure within the coil may be so fixed as to prevent vaporzation within the coil and permit the conversion of sensible heat to latent heat in tower 42, as hereinafter more fully described. Assuming that the vaporizatio'n is effected Within the coil, the oil thus heated and partly vaporized enters tower 42, rwhich may have any known eicient internal construction.' In this tower the vapors are condensed. A small proportion of stink oil, comprising also' incondensible gases, escapes through line 43 and condenser 44 into receiving tank 45, whence the condensed stink oil may be pumped to storage. Theniain part ofthe condensed product ows through line 46 into a deodorizer 47, which is subjected to a high vacuum and in which the remainder or" the odor-producing gases are removed, the puriiied oil flowing through a cooler 48 into a tank 49, from which it is pumped to storage.

The absolute pressure in tower 42 is maintained at such a point as will enable the vaporisation, in coil 4l, of the desired proportion of oil at as low a temperature as practicable. This high vacuum may be established and maintained through vacuum lines 50, 50.

vThe oil not vaporized in tower 42 and not escaping through line 46 flows through another coil 51 inA another mercury vapor condensing chamber 80. Herein the oil is heated to a somewhat higher temperature than in coil 41, resulting in another partial vaporization, and flows into a tower 52, wherein the vaporized fraction is con-` densed: the operation being the same as intower 42, but with the production of a higher boiling range oil distillate.

I have shown still another mercury vapor condensing chamber 89,-ccil 51 and towerv62, in

series with the fractional distillation units 70, 41, 42 and 80, 51, 52, above described, for the production of a still hie'lier boilingY range distillate. There may be a variable number of these units, dependent on the neness of the cuts desired, and dependent also on the proportion of the distillates which it is desired to produce by the use of mercury vapor as a heating medium ascompared with the proportion of relatively light distillates which it is desired to obtain in the preliminary distillation hereinbefore referred to, forming no part of the present invention. Other factors also will govern the design of the plant. With the use or a considerable number of units, the temperature elevations in each unit will be reduced, with the resultant advantage that the oil will be subjected to the action of the heating medium for very short periods of time.

Any number of boilers may be used. In the drawing is shown two boilers, "Il and 81, with mercury vapor outflow lines 72 and 82 respectively and mercury condensate return lines v76 and 86 respectively. Boiler 71 is shown as connecting with oil heater rIO and boiler 81 with oil heater 89, while each boiler is connectible with oil heater through branch mercury vapor inlet pipes 720 and S26 respectively and mercury condensate return line 78, which latter may be connected with'either line 76 or line 86 through one of the goose-necks 84. Mercury vapor lines 72 and 82 may be, cross-connected by means or" pipe '700. Chambers 77 of the mercury condensate returns to the two boilers may be cross-connected by means of pipe 110. Valves 111 are positioned in the short pipes connecting chambers 77 with their respective boilers and a valve 112 is positioned in the cross-connecting pipe 11i). Thereby, either boiler may be connected, and the other disconnected, with all the `oil heating chambers.

The described arrangement of boilers` may be varied as desired. The use of two boilers is desirable, since it allows the generation of mercury.

vapor atpressures more nearly approximating the pressures desired in the oil heaters connected therewith and it also provides against a shut down in case one boiler should be disabled. One boiler,` however, is all that is required, in view of the capacity to independently regulate the pressures in the several chambers'by means of the throttle valve 73, 83 or 88 and the balanced mercury columns in the goose-necks '775, 84 and 85.

While, as hereinbefore described, the partial vapoi-ization of the oil Rowing through coils 41, 51 and 6l occurs in the coils themselves, it may be preferable to prevent vaporization within the coils, thereby preventing any direct transfer of heat to the vapors. This can be eiected by means of pressure regulating valves 101, 102 and 103 on the pipes leading from the coils to the towers 42, 52 and '62. .When this variation is adopted, it is lnecessary to heat the oil'in each coil to a somewhat higher temperature than would be otherwise required to permit the conversion o sensible heat to latent heat in the succeeding tower. Such variation of the process is also of advantage in which the oil must be raised therein is comparatively low. In the absence of pressure control regulators, the oil in each coil will be under a vacuum but little lower than that in the tower, 42, 52 or 62, just beyond the coil.

It is desirable that provision be made to shut the boilers down if it becomes necessary to shut off the flow of vmercury to the oil heaters. Should the main valves 94 on lines 72 and 82 be closed, the safety valves 95 would open and the mercury would rise and condense in condenser 96, flowing back, through the seals 97 into lines 76 and 86 and thence into the boiler.

ItY should be understood that the present invention is not dependent on the use of any particular type of still. The stills above described merely illustrate one type of still with which the mercury boilers may be connected as herein described; but

the same connections may be made to stills of many different specific constructions.

What I claim and desire to protect byLetters Patent is:

l. The combination with a plurality of stills arranged in series, of two mercury boilers, a mercury vapor flow pipe from one boiler communicating with one Vor more stills and a mercury vapor .iiow pipe from the other boiler communicating with one or more other stills, and a crossconnecting mercury vapor flow pipe connecting the mercury vapor ilow pipes from the two boilers.

. 2. The combination with a plurality of stills arranged in series, of two mercury boilers, pipe connections providing for a ow of mercury vapor from one boiler to one or more stills and for the return of condensed mercury to the boiler, pipe connections providing for a flow of mercury vapor from the other boiler to one or more other stills and for the return of condensed mercury to the boiler, and valve controlled crossconnecting pipes permitting iow of mercury Vapor from either boiler to all the stills and for permitting return of condensed mercury from all the stills to either boiler.

3. The combination with three stills arranged in series, of two mercury boilers, a mercury vapor vflow pipe from one boiler to one end still anda mercury vapor flow pipe from the other boiler to the other end still, a mercury vapor flow pipe to the middle still, and means to connect the mercury vapor liow pipe to the middle still with the mercury vapor ilow pipe from either mercury boiler.

4. 'Ihe combination with three stills arrange in series, of two mercury boilers, pipe connections providing for a ow of mercury vapor from one boiler to one end still and for the return of condensed mercury to the boiler, pipe connections providing for a flow of mercury vapor from the other boiler to the other end still and for the return-of condensed mercury to the boiler, pipe connections providing for flow of mercury vapor to the middle still and for return of condensed l mercury thererom, and means to connect the iiow pipes to and from the middle still with the corresponding flow pipes to and from either of the other stills.

5. The combination with a plurality of stills arranged in series, of two' mercury boilers, a mercury vapor iow pipe from one boiler communieating with one still or combination of stills and aV mercury vapor flow pipe from the other boiler communicating with another still or combination of stills, and a cross-connecting mercury-vapor from the other boiler to another still and for the return of condensed mercury to the boiler, and Valve-controlled cross-connecting pipes permitting flow of mercury vapor from either boiler to both stills and for permitting return of condensed mercury from both stills to either boiler.

ARTHUR E. PEW, JR.

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