US1880851A - Method and apparatus pob treating hydbocabbons - Google Patents

Description

Oct. 4, 11932. A. G. DAVIS METHOD AND AFPARATUS FOR TREATING HYDROCARBONS Filed July 17.1928 2 Sheets-Sheet 1 m H We Oct. '4, 1932. A. G. DAVIS mmnpn AND APPARATUS FOR TREATING HYDROGARBONS Filed July 17, 1928 2 Sheets-Sheet 2 F/au i 2 V firm nu:

Patented 0a. 4, 1932 .-ly govern the crude.

NI D STA ES PATENT OFFICE AIBEBT G. DAVIS, 01' ELIZABETH, NEW JERSEY, ABSIGNOB, B! IESNE ASSIGNMENTS TO GASOLINE P30131701? 00mm, 1110., 01' WILIINGTON, DELAWARE, A. CORPORATION 01' DELAWARE Application Med Jul; 1?,

The major purpose of this invention is to provide a treatment for heavy or high boiling int hydrocarbon oils in which the oil is subjected to heat and pressure conditions of such character and magnitude as'will cause conversion of the oil, that is to say will insure the formation of appreciable quantities of' lower boilifi point ydrocarbons.

Another ect of the invention is to exercise an accurate control ofthe thermal conditions obtaining in the separate stages of the process.

' A furtherob'ect is to efliciently and cheapcluracter of the vapors which are condensed to produce the final distillate.

Yet mother object is to distill 06 the lighter fractions of the synthetic crude by utilization of heats develo d in the heatin stage.

A further ob ect is to control t e evaporation of lighter fractions from the synthetic With these and other equally important objects in view, the invention comprehends the idea of cracking relatively heavy oil by subjecting it to such temperature and pressure conditions as will cause the conversion to take lace substantially in liquid phase, and passmg' the fluid products of conversion to a reduced ressure sta wherein the contained heat 0 the oil is utilized for the distillation .of lighter products. In the-distillation sta the tem rature of the synthetic crude 1s modifi ucts thus controlled. I In'the preferred meth- 0d of o ration this thermal'modification is accomp ed by utilizing certain fractions of the oil which is undergoiugtreatment and thus obtain a continuous and, so to speak, self containedprocessr I I To enable a ready comprehension of the underl principles of the invention there is shown m the accompan g apparatus'which efiective y carries/out the several steps. This apparatus is shown dial0 grammatically and is to be taken as carbon medium. The

and the character of overhead proddrawings an a mason AIID APPABATUS IOB TREATING HYDBOCABIBONS 1988. 'Scrlal Ho. 893,822.

any comparable system which will function'in an equivalent manner. In these drawings; Fig. 1 is a diagrammatic side elevation view of the complete unit;

Fig. 2 is a detail view of a section of the unit which is connected to the evaporating tower; Fig. 3 is a detail-view showing a modified form of the apparatus disclosed in Fig. 2. It has been roposed, heretofore, to carry out the conversion of oil by passing it through heating tubesto a reaction stage while imposing pressures of the magnitude of thirty atmospheres or more, and then distilling off the lighter fractions by a quick reduction of pressure. In carrying out such a process, however, a large quantity of the heavier fractions are distilled ofi, and hence an unnecessarily heavy .load is imposed upon the dephle ator or fractionating apparatus. In addition to this a deposit of carbonaceous material of very high viscosity settles out in the evaporating stage. In some instances, as where the temperature of the synthetic crude is very high, the distillation may be so complete as to leave a solid 'cokey residue in the evaporating tower. Material in this form, as is known is most difiicult to remove and necessitates an expenditure of consider- .able time and labor in its removal.

In accordance with the present invention these disadvantages are obviated by modifying the temperature of the synthetic crude, to any of a cooler relatively carbon-free hydroreferred economical andeflicientmethod o achieving this temperature control comprises the introduction into the synthetic crude of a quantity of hydrocarbon oil which has been preliminarily treated to .free it of any suspended carbon which has been cooled to the desired extent. Such a method is peculiarly advantageous; not only does it permit the attainment of a definite control of the extent or degree of vaporization, but it also insures a hi h, flu dityof the unvaporized material in t e evaporatin stage'and hence facilitates the subsequent andlin of such fractions.

Theapparatusw 'ch may be utilized to desired degree, by the introduction understood by thoseskilled in the art. The:

which are connected to form a continuous sinuous coil. The several sections constituting the coil may be so positioned with re-, spect to each other and to'thecontiguous furnace walls as to insure the optimum conditions .of heat transfer.

ments of the apparatus by an inlet a discharge or outlet line 8. I

The operation of this furnace will be line and fuel is ignited in the combustion zone 3 and the hot gaseous products of combustion are deflected over the bridge wall, passin downwardly over the several heating tubes and outwardly through the flue .9 and stack 10.

Since the tubes are confined within a closely adjacent and substantially coextensive chamber, full use'is made of the radiant as well as the convective heata tubes are supplied with oil from .a plura ity. of sources. As' shown in The heatin the drawings, a feed line 11 leads from a source of supply (not shown) to a charging pump. 12. The discharge side of the pum is connected to a continuation 13 ofthe' eed .line which leads to and communicates with the inlet pipe 7. This line 13, as shown, is

convoluted as at 14 to form a preheating coil. This .coil is positioned in the upper section of. the evaporator and adjacent thevapor discharge en A second and independent feed-line 15 is connected to a charging pump 16. This feed ,line and pump is mounted in communication with the furnace inlet line 7 by the branch .line 17. The line 15 serves as a-conduit-for oil from certain elements of the apparatus,

in a manner to appear more fully hereinafter.

, The discharge side of the heating stage communicates with the reaction zone through which the oil is moved at such a rate as to providethe necessary periodof time to complete the conversion reactions. This time actor may be insured by passing the oil through an elongated tubing in which the desired temperature and pressure is maintained,

-or by utilizing an enlarged reaction chamber in which the speed of flow is reduced and the oil thus retained for the requisite period under conversion conditions. In the present process the second method is preferred. This is effectuated by utilizing an enlarged reaction chamber 18 suitably emplaced on supporting piers 19. I v

The heatin coil is P ative1y associated with the ot er .ele-- vapor drawofiz' line, as s size of the dephle 1,sso,sai

This chamber is preferably formed from a single piece of metal, having high tensile strength, low corrodibility and reactive characteristics. metal may be extruded or otherwise treated to produce a um'taryelongated container of substantially uniform metallic texture, free from seams, laps and other defects. Preferably the container is shaped with bottle-neck ends 19, which are suitably flanged to receiveremovable end closures. The chamber is. tapped to receive a pressure gauge 20 and, if desired, any preferred type of temperature indicating device Y (not shown) The chamber is connected with the heating unit b the line8. As shown, the discharge end 0 this line communicates with the adjacent end of 'thereaction-chamber. The

other end of the chamber is connected by a discharge line 21 to an evaporator 22. Interposed in the chamber discharge line is a pressure reduction valve23. This, as will appear more fully hereinafter, serves to maintain apressure diiferentialbetween the reaction chamber and the evaporator and permits the evaporation of lighter fractions of the synthetic crude.

The evaporator is provided, adjacent its bottom portion, with a through which residual liquids may be discharged. .To insure a continuous operation penditure-the withdrawal of liquid is made automatic. -This may be accomplished by providing a control valve 25 operable, 1n the well known manner", by a liquid level regulating device 26. By this 'mechanismliquld residue in the evaporator is withdrawn and a tained. Y I

The oil vapor fractions which pass over from the evaporator are adapted to be further treated to secure the desired fractionapredetermined minimum liquid level maintion and to relieve the ultimate fraction of. any entrained or dissolved ases. To do this the eva orator is connecte by an overhead drawoif line 24 with the minimum of manipulative time exdrawo line 27, to a dephlegmator 28. The

own, leads from the upper section -or dome of the evaporator to the lower portion of the dephlegmator; In the dephlegmator the vapors are percolated through a vertical series of oil ools and are relieved of their heavier constituents. The ator, quantity. of liquld oil, tem erature o the successive pools and speed 0 flow of the vapors maybe regulated to secure the desired ultimate .vapor fract1on.

It will be appreciated that, if desired, the

ing medium; In the present method these conditions are-so adjusted'as to obtain a temperature of the several oil pools may be I I controlledby introducing an extraneous coolvapor product which has'the characteristics of commercial gasoline.

The condensates formed in the dephlegmator gravitate to the bottom and are automatically drawn off through the line 20. This automatic operation is secured by utilizing a valve' controlled by the liquid level regulating device 31, these two elements being similar to the valve and associated regulating device connected to the evaporator. This condensate is adapted to be recycled through the heating coils in a manner to appear more fully hereinafter.

From the dephlegmator the cleansed and fractionated vapors are drawn off through a vapor line 32 and subjected to condensation. This condensation may be achieved by convoluting the line 32, as at 33, to provide a cooling coil ofrequisite size. The cooling coil may be enclosed within a condenser box 34 supplied with a suitable cooling medium. The cooling medium is preferably passed in counter-current flow throughthe box. This medium, which may be water, oil, brine or any other suitable liquid, is admitted through the line 35 and withdrawn through line 36.

From the condensing stage the oil, together with incorporated gases, is passed through line 37 to the gas separator 38. This is provided at its lower portion with a'liquid drawoft' line 39 controlled by the valve 40. The gases, separated in this element, may be withdrawn through the overhead line 41 controlled by a suitable valve 42. This gas line 41 may connect with a storage tank (not shown) or communicate directly with the burners 5. The gasoline-like constituents withdrawn through the line 39 may be transferred to a storage tank or subjected to any desired subsequent treatment.

If desired, suitable valve controlled steam lines 43 and 44 may be connected to the lower portions of the evaporator and dephlegmator respectively, to facilitate separation of vapors. The ends ofthese pipes may be perforated to secure an equal and wide distribution of the distilling medium through the oil pool. By introducing steam into the evaporator a e and the initial boiling point of the residual products is' obtained. An introduction of steam into the dephlegmator facilitates the removal of the lighter ends and insures a clear-cut fractionation of the desired products.

The liquid drawofl from the dephlegmator connects with the feed line 15 by means of the pipeexten'sion 45. Interposed in the line 15, between the line 45 and the charge pump 16 is a controlvalve 46. Also connected in the line 15, at the other side of line 45, is a second controlvalve 47. By closing valve 47 and opening valve 46 all of the reflux con-.

densate from the dephlegmator may be recycled to the furnace. Similarly by closing valve 46 and opening valve 47 these condensates may be directe to storage. By fixing '55 the valves at intermediate positions any pre- 'The pressure may be maintained 400 to 1000 lbs. per square inch, depending tter control of the flash point determined quantity of condensate may be charged to the furnace to obtain the. desired mixture of reflux with fresh feed. When the apparatusv is on stream fresh oil, forced through line 11, is preheated in the coil '14 and, after any desired percents, mixture withvheated reflux, is charged to e furnace. In the heating stage the temcrat-ure and velocity of the oil is so reguated that it attains the cracking temperature and the conversion reaction is initiated. This control ofconditions is exercised so that. the major cracking reaction will take place in the chamber. By'this means car bon deposition takes place largely in the chamber, instead of in the tubes. This is advantageous for the reason that the removal of carbon from the chamber maybe accomphshed more expeditiously.

In the tubes the oil may be heated to temperatures ranging from 600 to 1000 F During its course of travel through the tubes and chamber the oil is subjected to pressures which are maintained at suflicient magnitude to retain the oil largely in uidphase. om about on the character of the oil treated and the tem eratures to which it is subjected.

T e hot oil is passed from the heating coils through a transfer line 8 to the reaction chamber 18. This, it will be understood, may be heavily insulated to conserve the heat attained in the tubes Due to this'enlarged area the chamber provides a zone in which the speed of flow. of the oil is considerably reduced and assures the necessary reaction time for the oil. The major quantity of carbon which has formed duringthe cracking reaction isdeposited in the chamber.

After the oil has traversed the length of the chamber it is passed out throu h the transfer line 21 to the evaporator." uring this passage the premure is relieved by means of the reduction valve 23. While any de sired degree of pressure may be maintained, 9 on the evaporator, dephlegmator, condenser and receiver, it is preferable to maintain 'these'elements at substantially atmospheric pressure. As the oil passes from the zone of high pressure, in the chamber, to a zone of lower pressure, in the evaporator, those fractions which will volatilize at the effective temperature of the synthetic crude will pass overhead. As evolved vapors and gases pass subjected to the cooling action of the fresh feed and certain of the higher boiling point constituents are knocked back. The remaining uncondensed fractions pass overhead through the line 27 and are injected into the lower portion of the dephlgmator. In-their upward travel through the dephlegmator. the vapors are progressively relieved of heavier fractions, in the manner described. The

upwardly through the evaporator they are lower boiling point or gasoline-like constituents which are uncondensed in the dephlegmator pass to the condenser 34 wherein the condensible components are liquefied.

From this'element the liquid distillate tgether with entrained or occluded fixed gases, are passed to the gas separator where'- in' the liquid and gaseous components are separated.

While such a process which utilizes the contained heat of the oil for distillation does present high heat economies, it nevertheless is subject to certain drawbacks. When high temperatures and pressures are employed in the conversion stage and the evaporator is operated at or near atmospheric pressure a very large pressure differential obtains. As a result there may be such a vigorous and extensive'distillation as to drive oil a greater part of the liquid products, leaving avery heavy sludge or even a solid residue. While the release of pressure by the valve 23'causes a rapid expansion of gases and vapors, the cooling efiect of these is not of such a magnitude as to sufliciently modify the tempera-- ture of theoil.

The present invention comprehends a method of overcoming the disadvantages by introducing into the synthetic crude a'cla-rified relatively. cool hydrocarbon, substantially none of which will volatize at the temperature and pressure conditions obtained in the evaporator.

The advantages of such temperature than the synthetic crude it serves as a temperature modifying medium by exercising a cooling eflect on the hot prodnets of conversion. It will be appreciated that by regulating the temperature and quantity of the injected oil, any desired degree of thermal control maybe obtained. Since the character of the vaporized'prod ucts 'is a function of the temperature of the oil body, the introduction of cooler oil serves to govern or'control the range of these volatiles.

into the bottom of the evaporator, such pre-- cipitated carbonaceous material as is present in the evaporator is more readily taken up and retained in suspension. r

These advantages may be secured by causing the residual oil in the evaporator to pass through a cooling and clarifying apparatus and then back into the oil pool in the evaporator. In this manner the 'oil which has ala step are mani fold. Since the injected oil is at a lower.

ready undergone distillation is employed and hence will contain only those heavier fractions which will notevaporate at the temperature conditions in the evaporator.

T e apparatus for accomplishing this treatment may comprise a coolin coil and an associated carbon separator. s shown, the drawofi line 24 is convoluted as at 48 and positioned within the cooling box 49.. As shown in more detail in Figure 2, this cooler is'provided with a fluid inlet line 50 and discharge line 51 so that the device operates on the counter-current flow principle. The cooling medium may be water, brine, oil, or any other desired fluid.

The end of the cooling coil 48 connects with the upper portion of a carbon trap 53. This trap may comprise a closed cylindrical container having a conical bottom portion 54. Connected to the bottom of the conical portion is a valve residue drawofi line 55. Positioned within the main container is a cylindrical stand pipe 56. fastened to the upper closure of the trap and at its bottom portion is in open fluid communication with the interior of the trap. The end of the stand pipe is preferably formed with a foraminous member or screen 57 which permits the passage of liquid oil but obstructs the flow of suspended solids. If desired the trap may be covered with initagle insulating material 52, as shown in The outlet of the cooling coil 48 communicates with the annular chamber defined by the concentric members 53 and 56. The

outlet pipe 58 passes through the top of the trap and descends well into the interior .of the stand pipe; The other end of this pipe is connected, through the chargingv pump 59 and feed line 60, to the transfer line21 on the low pressure. side of the valve 23. While the line 58 isshown as directly connected to the pump,it will be understood that it is within the scope of the invention to interpose an accumulating or cooled oil By utilizing a storage tank of this character a constant source of cold tempering oil is made available for the evaporator. This accumulating tank, it will be understood, may be connected to a larger oil storage tank to which oil in excess of that required for cooling purposes may be directed. f an accumulator tank is not employed the excess ofclarified oil maybe drawn oil through the line 61 to suitable storage.

The operation of these associated elements will have been appreciated from the foregoing description. The residual oil in the evaporator is continuously passed through the cooler 48 and carbon separator 53. In the cooler the temperature of the liquid products is reduced. The cooled oil is dis charged into the annular spacebetween the n This is integrally storage tank between these two'elements.

pipe 56 and during)this passage lar er suspended solids are structed by the ter 57.

It will be understood 'that in lieu of a single foraminous member 57 several such members may be employed. These, if desired, may-be of varying mesh so as to insure a more com- -plete separation of' solids. The clarified supernatant oil is withdrawn through the line 58 and discharged to an accumulator tank or directly to the evaporator.

As shownin Figure .3 the cooling and clarification may be accomplished in one apparatus. This may be done by eliminating t e cooling coil and housing the carbon separator 53' directly within a cooler box 4 This cooler, like condenser 49 is provided with cold medium inlet line' 50' and outlet 51. In operation of this device the cooling medium in the cooler abstracts heat from the hot oil admitted to the separator through line 24. This oil, in its downward passage in the separator, is cooled and the eavier material settles, while the clarified lighter material rises inthe stand pipe and is withdrawn through the drawofi line 58'.

As has been pointed out hereinbefore the oil which is treated in the se arator has previously been subjected to distillatlon conditions and hence. has been relieved of sub- I stantially all of those fractions which will f vaporize at the temperature and pressure conditions in the evaporator. In this manner a hydrocarbon tempering medium is employed which not only exercises the desired temperature control, but also serves efiectlve- 1y as a flushing agent and solvent for the residual material'in the tower.

It will be understood, of course that two or more carbon traps may be associated with the tower and bypassed to the tower so that they may be cut in and out to permit cleaning lpf one while the other is in operation.

0 present processpermits a very accurate.

control of the overhead products, for by modifying the temperature of the synthetic crude in the evaporating stage practically 1 any desired fractionation can e obtained at the initial point of distillation. In addition to this, the character of the evaporator bottoms is so controlled or overned that from such residues a; market le fuel oil may be readily secured.

While a particular a paratus has been described as being especi y suited for the procem, it is to be understood that any mechanical modification which will subserve functions may be employed.

Iclaim: I 1. A process of converting vhydrocarbon oil comprising subjecting the ml to cracking conequivalent rate heating and digesting stages, passing the products of conversion to an evaporating stage maintained at a pressure materially lower than that in the digestin stage, distilling off the lighter fractions 0 the products of conversion, withdrawing unvaporized products from the evaporating stage, cooling and removing solid carbonaceous material from the unvaporized products and cooling the products of conversion before assing them to the evaporating stage by mixing the m ditions of temperature and pressure in sepa- I cooled carbon free unvaporized products with I the'products of conversion from the di es- 1 tion stage before introducing the same mto the evaporating stage.

2. An evaporating apparatus for treating petroleum products comprising a tower, a liquid inlet to the tower, a pressure reduction valve in the inlet line, a discharge line for the tower, a cooling device and carbon separating chamber interposed in the discharge line and a fluid conduit directly con nected to said chamber and the side of the inlet line.

3. A process of treating hydrocarbon oilscom rising subjecting the oil to conversion con itions of temperature and pressure in a heating zone, passing the oil from the heating zoneto an enlarged reaction zone wherein the conversion instituted in the heating zone may be consummated, passing the products of conversion to a vaponzin .zone maintained at, a reduced pressure w erein light fractions of the products of conversion will be vaporized, withdrawing and treating the vapors to obtain desired fractions, withdrawing the unvaporized residue from the vaporizmg zone, cooling it, separatin carbonaceous suspended matter mixing t e clarified low pressure residue with the products of conversion passing to the vaporizing zoneprior to introducing the products of conversion into the vapor- I izing zone' to temper the products or. converslon and prevent excessive vaporization.

4. An apparatus for convertinghydrocarbon 011 comprising a furnace havin a coil therein, an enlarged digestion cham er connected with said coil, and means for forcing a hydrocarbon. oil through said coil into the digestion chamber, an evaporator, a conduit connecting the discharge end of said digestion chamber with the evaporator, and" means in said conduit for reducing the pressure on material passingv from the digestion chamber to the evaporator, a'carbon separating chamber, a discharge line from the lower portion of said evaporator connected with the inlet to said carbon separating chamber,

means interposed in saidline for cooling material passing from the evaporator to the earbon separatin chamber, and means for withdrawin clari ed oil from said carbon sepa- 5 rating 0 amber and introducing the same into with the evaporator.

the conduit connecting the digestion chamber ALBERT DAVIS.

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