US1842756A - Oil distilling system - Google Patents

Description

jan. 26, 1932. J. B. HILL OIL DISTILLING SYSTEM Filed May 14. 1926 lulllllllll Jan. 26, 1932. J. B. HILL OIL DISTILLING SYSTEM Filed May 14, 1926 2 Sheets-Sheet 2 atente Jan. 26, 1932 'STATES'Y PAT-ENT .ori-ice JEPH )BENNETT HILL, F BHILADELPHIA, PENNSYLVNIA, ASSIGNOR T0 THE ATLANTIC REFINING COMPANY, 0F PHILADELPHIA, PENNSYLVANIA, A GORPOBA- 'rron or ranasxtvama om Diaframma srsrrm Application led Hay 14, 1926. Serial No. 109,005.

Myinvention relates to the art of distillation of hydrocarbon oils, such as petroleumf` and its products and oils derived from coal, shale and analogous materials.

ln accordance with my invention, a body of the oil is heated by effecting combustion of a suitable fuel While submerged in and in direct Contact with the oil, and more particularly, the aforesaid fuel comprises a mixture of a l@ combustible gas and a combustion-promoting transfer of heat thereto.

ln the commonly used methods of distillation ofhydrocarbon oils, the oil to be distilled is heated by indirect heat, conducted through the Walls of the containing vessel which is usually built within or above a heating chamber. The Walls of the vessel attain a temperature considerably in excess of that of the oil due to the poor heat transfer from the metal container to and through the oil. As a result, the film of liquid immediately adjacent to the heated surface is subjected to local overheating which, in the case of some oils, and particularly so with petroleum, may cause'decomposition. This effect may be partially overcome by keeping the oil in motion either by passing it at high velocity throughheated tubes or by agitation, as by blowing steam through the liquid oil, but local overheating of the film-is never completely eliminated by such means.

Furthermore, distillation by external api plication of heat to the ontainer is relatively inefiici ent dueto the hea loss in the flue gases, radiation from the furnace, etc.

rlhe external firing of stills, particularly those used for distilling petroleum, presents further difficulty, in that When decomposition of. the liquid occurs due to local overheating a ifA =j.of carbonaceousmaterial or coke builds the still bottom and, due to its low thermal conductivity, the metal may become overheated resulting in -damage to the still.

For the distillation of oils having boiling points which are in excess of the temperature at which substantial decomposition occurs it has been common practice to adopt some means to eect vaporization'at a lower temperature. This may be done by distillation under vacuum or by passing through the liquid a heated gas or vapor, as steam, which by its partial pressure reduces the vapor pressure which must be exerted by the liquid in order that it may vaporize.

l have found that distillation of hydrocarbon oils may be economically effected by the use of a suitable burner, designed to burn a carefully controlled mixture of a combustible gas and an oxygen containing gas, such as air, immersed in a body of the liquid oil to be distilled and whereby combustion of the mixture may take place with the liquid oil as a surrounding medium. y

ln accordance with the method of this invention distillation of combustible liquids, particularly* hydrocarbon oils, is effected by bringing the dames and products of combustion, resulting from burning of a suitable fuel, directly into contact with a body of sel), thereby heating and vaporizing portions thereof. When using the immersed burner as aforesaid I have found that combustion of the oil to be distilled can be avoided by carefully regulating the proportions of the gases in the gas mixture fed to the burner so that substantially no excess oxygen over that required for the gaseous combustion is present, and, therefore, the gases which enter the oil at flame temperature are substantially' free from oxygen and are unable to enter into combustion reactions with the oil. By my process, I am able to avoid most of the difficulties mentioned above as attendant to the commonly used methods. Furthermore, as the products of combustion pass through the liquid they have the same eect of causing distillation at lower temperature that the application of steam or vacuum has in ordinary distillation.

My invention resides in the method and apparatus of the' character hereinafter described and claimed.

For an understanding of my method and for an illustration .of some of the Various forms of apparatus within my invention reference is to be had to the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of apparatus constructed in accordance with my invention.

Fig. 2 is an enlarged vertical sectional View showing a conduit supporting one form of ignition apparatus for igniting the gas traversing said conduit.

Fig. 3 is a plan view, partly in section, showing a plurality of ignition structures connected in an electric circuit.

Fig. 4 is a diagrammatic View of another form of apparatus constructed in accordance with my invention.

Fig. 5 is an enlarged vertical sectional iiew of a part of the structure shown in iof. 4.

F-eferring to Fig. 1, there are illustrated the columns or supports 1 upon which rests a still A comprising the steel shell or jacket 2 enclosed by suitable heat or thermal insulating material 3. The oil to be distilled is charged to the level L through the line 4 controlled by the valve 5. The line 6 controlled by the valve 7 serves as a drawoff for the oil in the still.

A line 8- controlled by valve 9 leads from the dome 10 of still A' to a condenser C mounted on suitable supporting structure 11. Connecting with condenser C is a line 12 leading to a gas separator S mounted upon the support 13. From separator S, oil may be passed to storage or other suitable destination through the line 14 controlled by valve 15. Communicating with the top of the gas separator S is a line 16 controlled by a valve 17 through which the uncondensed gases may be passed to an oil recovery system, notk shown.

In accordancewith my invention the oil contained in still A is heated by effecting .combustion of fuel while submerged in and 1n direct contact with the oil. To this end, when a gaseous fuel mixture is utilized, a pipe or conduit 18 mounted interiorly of and adjacent the bottom of still A may project exteriorly thereof into communication with a mixing chamber 19 into which opens 21, a suitable pump 22, or equivalent, being utilized to force air or other combustiongas promoting gas, hereinafter generically termed air, along conduit 2O into chamber 19. A second pipe or conduit 23 controlled by a valve 24 has interposed therein a pump 22a or. the like utilizable for forcing a combustible gas, preferably one produced in petroleum distillation, along conduit 23 into j the chamber 19.

.Conduit 18, interiorly of still A, is provided with a plurality of lateral openings preferably threaded to receive the exteriorly threaded end portions of the cylinders or tubes 25, preferably metallic in character, Figs. 2 and 3. Each tube 25 adjacent its other end is provided with a plurality of perforations 26, preferably circumferentially ai'- ranged, and forming the sole means of communication between the interior of conduit 18 and the interior of the still A.. Mounted in each tube 25 is a plug ory diaphragm 27, preferably of metal. When an electrical ai'- i'angement is utilized for igniting the gas passing into the body of oil in still A, it is desirable, when tubes 25 and plugs 27 are constructed of metal,'that a member 28 of suitable insulating material be disposed between each plug 27 and the adjacent surface of the tube 25associated therewith. Each plug 25 is provided with one or more passages oi' orifices 25a of restricted diameter.

Thecombustible mixture issuing through passages v25a may be ignited in any suitable manner. Merely by way of example, I have illustrated one type of ignition apparatus for producing electric sparks adjacent the outlets of passages 25a. To this end, each plug 27 may be provided with a spark gap structure comprising a pair of discharge points 29 Vand 30, the former being welded or otherwise suitably secured in conductive relation to plug 27 and the latter extending through a passage herein but insulated therefrom by a. member 1 of suitable insulating material, as mica. As well understood in the ignition art, the tips of discharge points v29 and 30 should be spaced a suitable distance apart to insure the development of sparks of the proper characteristics.

As herein shown by way of example, conductors 32 and 33 pass from a suitable source of high tension current, as the induction coil 34, int iorly of conduit 18 for connecting the pairs o discharge points 29 and 30 in series. Low tension current is suppliedA from any suitable source to coil 34 by conductors 35 and 36 in one of which may be interposed the switch 37.

With the oil charged in the still to the level L, the air and gas pumps 22 and 22a are placed in operation and, by adjustment of valves 21 and 24, the desired proportions of fgas and air are passed to the mixing chaina pipe or conduit 2O controlled by a valve'y ber 19, where thorough mixing occurs, and thence to the conduit 18. From conduit 18, the combustible mixture passes through passages 25a in plugs 27 of the submerged burnica A ers at a velocity suiiiciently high to prevent back-firing into conduit 18 when the issuing mixture is ignited in the tubes 25 beyond the plugs 27. The velocity of the issuing .combustible mixture is also sufciently high to prevent flow of the oil from still A through passages 25a to the interior of conduit 18. Upon closure of con'- tact key 37 a spark is passed between each pair of discharge points 29 and 30, thereby ignitin the combustible mixture. The flame products of combustion pass upwardly through the oil and cause further heating.

ln'the early stage of distillation very litt-leoil vapor passes with the products of combustion from the still A to the condenser C gases 'and the latent heat of vaporization o the oil. Under these conditions the oil is distilled at a temperature considerably below its boiling point producing the saine eflect as distillation with steam in the commonly practiced Imethods.

The temperature of still A may be regulated by dilution of the combustible mixture-` with an inert gas obtained from any suitable source of supply, By preference, however, such inert gas is obtained by recycling a. desired portion of the spent.combustion gases after the oil vapors have been condensed therefrom. To this end and as herein shown, the line ld through which the gases pass from the gas separater S may be tapped by the line 38 controlled by the valves 39 and 4l() for passing a desired quantity ot spent gases to the inlet conduit ll ot pump 22a, such spent gases eventually reaching the chamber l@ where mining occurs with air and the combustible gasesu The temperature ot still A may also be regu- Jto a condenser @l from which a line 68 leads lated by operation. ot valve 9 to vary the pressure thereon. An increase in pressur e has the effect of increasing the partial pressure ot the combustion gases. Since the ratio of: the weights of oil distilled to combustion gases and, therefore, the ratio ot the partial pressureot the oil vapor to that ot the gases is lured by the heat balance and is approximatey independent ot pressure, the partial pressure of the oil vapor, that is the vapor pressure of the liquid oil, must be correspondingly.

increasedn Equilibrium will, therefore, be 'reachedx u higher temperature due to the `increased pressure ot the system. Siinilarlv a oecrease in the pressure of the system `vill result in a lower still temperature.

Since in niy process the heating of the oil is @one directly by the darne and the hot gases, the presence of a more or less permanent film at. the heating surface is eliminated and therdecoinposition of the oil in the film thereby avoided.u rlhe distilling liquid is maintained by the gases in a state of vigorous agitation and there is little possibility of superheated zones. The process has the additional advantage of very high thermal eiciency, since the radiation losses are low due to complete heat insulation of the still, and since the issuing combustion gases are only at the temperature of the still.- Furthermore there is no contact between the flame or hotl gases and the metal of the still and therefore no possibility of damage tothe still due to overheat-i ing.

- While `my invention has been described above in connection with a shell still, it shall be understood that suchdescription is definitive rather than limitive. As another asect of my invention, l have illustrated in tigs. 4. and 5 a pipe still A1 comprising the tubes, pipes o1' conduits 50 embedded in suitable heat insulating vmaterial 51. As shown, the ends of tubes 5() entend beyond the material 5l and are connected in series by the U- shaped coupling tubes or return bends 52 secured to the ends of adjacent tubes in any suit- 5able manner tor example, by securing flanges 53 forming the terminals of' itl-tubes 52 to corresponding ianges 542 forming the terminal of pipes 50 by bolts 55 or the like.

Connected to the lowerinost pipe 50, as viewed Ain Fig. 4;, is the line 56 leading to a suitable separating device herein 'shown as the fractionating column lll comprising the spaced plates 57 provided with the bubbler cap. structure 58 vand down flow pipes 59. Communicating with the bottom of column Fl is the line 60 leading to storage or other suitable destination. ll desired, portions ot the redux liquid descending.,r through column Fl may be withdrawn at difierent levels, by

the trapped lines 6l and 52 controlled, respeci tively, by the valves 63 and titl, through the coolers 65 and 56 and thence to storage.

A lined? leads from the top of column lll.

to a gas separator Sl. Communicating with the bottoni of separator Sl is a line 69 opening into a dow bds Bl to which isconnected a line l0 4for passing a stream ot liquid'oilto storage. lt desired, there may be provided a conduit ll for passing oil from `flow box Bl 1.

to column Fl where it serves as retluning liquid..

combustible mixture ot a gaseous fuel and air maybe passed into direct contact with the oil tion/ing through the tubes 50 in any suitable manner. By way of example, l have shown the lli-shaped coupling tubes 52 at each end of the still provided with bosses 7 2, cach interiorly threaded to receive the exteriorly threaded end portion ot a tube or cylinder 73 corresponding generally with the tubes 25, Fig. l. The ends ot cylinders 73 in which are formed the pertorations 26 extend Well Within the tubular structure comprising the pipes 50 and lll-shaped coupling tubes 52 While the other ends of said cylinders 73 extend exteriorly of the coupling tubes 52 and, by suitable fittings 74,75 and 76 are connected to the conduit system 77 through which passes the combustible mixture from any suitable source, not shown, as a mixing chamber and associated pumps for supplying a similar mixture to and through the conduit 18, Fig. 1.

In the example illustrated, cylinders 73 are equipped with spark gap structures of the character shown in Figs. l, 2 and 3, the coacting electrodes or sparking elements 29 and 30 of all the structures being connected in series by the conductors 32 and 33 leading from the induction coil 34 into the conduit system 77 through which they are extended to the various spark gap structures.

The operation of the form of my invention shown in'Figs. 4 and 5 is essentially the same as described above with respect to Figs. 1, 2 and 3. Oil is pumped to the still through the extension a of the uppermost tube and thereafter flows through the tube structure in the direction indicated by the arrows, Fig.

4. At the same time, the combustible mixture is supplied through the conduit system 7 7 and, after the air has been expelled from the tube structure 50, 52 by the oil, switch 37 is closed to ignite the combustible mixture, the products of combustion thereafter thoroughly mixing with the oil.

The heated mixture of oil, vapors and combustion products pass from still A1 through the line 56 to the fractionating column F1 in which the gases and vapors pass upwardly in contacting relation with the descending reluxrliquid, the unvaporized oil being drawn from the bottom of the columnV through line 60. The vapors pass from the top of column through line 67 to condenser C1 and thereafter through line 68 to separator S1. If desirable, and in a. manner similar to that described above with respect to Figs. 1, 2 and 3, gases for dilution purposes may be transferred from the separator S1 by way of line 7 8 controlled by valve 79 to the intake of the pump supplyingsa. combustible gas to the conduit system 77.

It will be observed that the cylinders 73 and associated spark gap struct-ure are so located in the tube structure 50, 52 that the burning gases issue from the perforations 26 in the direction of flow of the oil thus aiding in its passage through the tubes. Should the oil be pumped into still A1 through the lowermost tube of the/series, cylinders 73 and associated structure would preferably be located in the upper portion of the U- shaped tubes 52 so that the burning gases would still issue in the direction of flow of the oil.

What I claim is:

1. A process for distilling hydrocarbon oil, which comprises mixing in a zone combustible, oxygen-containing and inert gases, passing the gaseous mixture from said zone into a body of oil, burning the gaseous mixturel while submerged in and in direct contact with the oil, collecting the products of combustion, and introducing at least a portion of said products into the zone wherein are mixed the combustible, oxygen-containing and inert gases.

2. In combination with a still for Vaporizing 'hydrocarbon oil, means within the still for heat-ing the oil comprising a conduitiex- Vtending adjacent the bottom of said still,

means for conducting a combustible gas into said conduit, burners communicating with said conduit, and means within said burners for igniting the combustible gas, whereby flames resulting from combustion of said gas are submerged in and directly contact with the oil.

3. In combination with a still for .Vaporizing hydrocarbon oil, means within the still for heating the oil comprising a conduit extending adjacent the bottom of said still, means for mixing a plurality of gases, means for introducing the gaseous mixture into said conduit, burners communicating with said conduit, and means within said burners for igniting the gaseous mixture.

4. In combination with a still for Vaporizing hydrocarbon oil, means within the still for heating the oil comprising a conduit extending adjacent the bottom of said still, a mixing chamber, means for separately supplying gases to said chamber, means connecting said mixing chamber and said conduit, burners communicating with said con-V duit, and igniting means within said burners.

5. In combination, a still for heating hydrocarbon oils, a conduit within the still adjacent the bottom thereof, means for conducting a combustible gas into said conduit, burners communicating with said conduit, and igniting means associated with said burners, whereby flames resulting from combustion of said gas are submerged in and directly contact with the oil.

6. In the art of distilling hydrocarbon oil, the method which comprises burning a com bustible mixture while submerged in the oil, effecting direct contactof the products of combustion with the oil, and controlling the temperature resulting from the combustion by regulating the pressure upon the body of oil.

7. In the art of distilling hydrocarbon oil, the method which comprises burning a combustible mixture While submerged in the oil. effecting direct contact rof the products of combustion with the oil, and controlling the temperature resulting from the combustion l by diluting the combustible mixture with an lnert gas prior to its introduction into the oil.

JQSEPH BENNETT HILL.

Images