US1962235A - Method of and apparatus for cracking oil - Google Patents

Description

June 1,2, 1934.- L. DE FLoRl-:z

I METHOD 0F AND APPARATUS FOR CRCKING' OIL Filed Dec. l1, 1923 INVENTORl if ORNEY Patented June 12, 1934 PATENT OFFICE METHOD F' AND APPARATUS FOR CRACKING OIL Luis de Florez, Pomfret, Conn., assigner to The Texas Company, New York, N. Y., a corporation of Delaware Application December 11, 1923, Serial No. 679,882 34 claims.v (ci. 19e-4s) My invention relates to improvements in a method and apparatus for cracking oils to produce low boiling hydrocarbons from similar material having relatively high boiling points. An

5 object of the present inventionis to .produce in commercial quantities a distillate of suitable characteristics to be used as fuel in internal combustion engines, and to increase the lamount of distillate having the low boiling characteristics relative to the amount of crude oil supplied. My invention is intended further to produce generally lighter 'and lower boiling hydrocarbons from heavier and higher boiling hydrocarbons, and to effect the cracking of an oil in two stages, namely, to take a heavy crude, distill ofi the gasoline, crack the intermediate distillates, and use the heat which the cracked oils contain and further crack the residuums which have been left in the still. This can be effected by the use of one or ing the heavier oils in this manner, the carbon formed is not so likely to stick to the shell of the still since there is relatively a small amount of heat applied to the heavy oils exteriorly of the shell, thus making it easier for cleaning.

My invention is intended further to provide means for mixing the cracked vapors with the heavy oils to effect additional cracking in the heavy oils or a desirable distillation. The cracking of the lighter oils, and the use of the'heat of this operaion to effect additional cracking, shows a considerable gain in operating costs. My invention is intended further to eliminate to a great extent carbon'trouble in the cracking still by the use of a light distillate. As will appear from the description which follows, the whole method of distilling a'crude, separatin/g the cracking stock, cracking the heavy oils under different conditionsin such a manner as to prevent the deposit of carbon from affecting the heating, will be preferably carried out as a cycle, although these operations can be separated by tankage.

Reference is to be had to the accompanying drawing forming a part of this specification, in which similar reference characters indicate corresponding parts. y

The figure is a diagrammatic view showing the general arrangement of vlthe apparatus for carrying the method into effect, in which the various elements may beof any approved kind.

In the drawing 10 represents a source of oil supply, from which leads a pipe 11 to a pump 12 which forces the' oil through a pipe 13 into a common cylindrical still 14 or the like andthis may be provided with any suitable furnace 15 two stills as shown by the drawing. By crack.

for raising the oil in the still to the desired temperature. Rising from the still is the customary dephlegmator tower 16, and from the upper part of this leads a pipe 17 through which the low boiling'fluids of the naphtha, gasoline, benzine 60 type, pass off naturally as the result of distillation through a condenser 18 to a receiving tank 19, from which these products pass through a pipe 20, pump 21 and pipe 22 to the storage tank 23 for the distiuates. Up to this point the prac- 65 tice is simply normal distillation.

At a lower point in the tower 16 the intermediate or cracking stock or gas oil is drawn off through the pipe 24 and condenser 25 to a tank 26, from which a pipe 27 leads to a pump 70 28. This forces the cracking stock through rthe pipe 29 to a tank 30 for the cracking stock. From this a pipe 31 connects with a pump 32 which forces the cracking stock through a pipe 33 having a valve 33a and meter 34 for 75 checking the flow, and through the pipe 35 to the cracking apparatus`36- This may be of any approved type, so long as it raises the cracking stock to a temperature above the cracking point, and I have shown diagrammatically the cracking still having two legs 3'7 and 38 extending down on opposite sides of a baille 39. The showing in the drawing is diagrammatic, the part 37 representing a pre-heating coil, and the part 38 a cracking coil. Between the two coils is preferably arrangedya separating chamber 38B which will permit the drawing oi through a pipe 38b of the heavy oils. The pipe 38b has a valve 38. The object of this separator is to remove such heavy high boiling hydrocarbons as would deposit an excessive amount of carbon if cracked., It is virtually the combination of a pipe still for preheating and a cracking still for cracking, with an expansion chamber between which permits the/removal of undesirable fractions before going into the cracking coil. From the cracking still 36 a pipe 40 having a valve 40a discharges into a second cylindrical still 41 of the type already reierred to, and this has a heating furnace 41e which may ormay not be used, according to circumstancesras' hereinafter explained.

The still 41 has a dephlegmator tower 42 from the upper part of which the tops of the distilled oil are drawn off through a pipe 43, heat exchanger 44, condenser 45, and into a gas tank i 46, which is really a settling or separating tank,

having a pipe 46e from which the gas may be withdrawn, and a. pipe 47 leading to the distillate storage tank. 'I'he pipes 46 and 47 have valves 46b and 47".

From a lower point in the tower 42 the cracking stock from the still 41 passes out through the pipe 48 and condenser 49 to the tank 50, from which it is conducted to a pump 5l, and by this forced through a pipe 52 into the cracking stock tank 30.

The bottoms or heavy oil from the still 14 are conducted through a pipe 53 leading to the pump 54, and the latter forces the heavy oil through a pipe 55, and here it may be given one of several courses, the purpose of which will be hereinafter explained. The pipe 55 connects by the pipe 56 having a valve 57 with a storage tank 58, and the latter connects by a pipe 59 with a pump 60 which connects by a pipe 61'v controlled by a valve 62 to the pipe line 55, the latter having a valve 55a between the pipes 56 and 61 so thatyif desired the valve 55a may be closed and the heavy oil forced through the pipe 56 into the storage tank 58, and by regulating the valves 57 and 62, the supply for further operations can be drawn either from the still 14 or from the storage tank 58, or from both. Obviously the supply drawn from the still 14 will be hotter than that drawn from the storage tank, and the future course of it will depend somewhat on this fact, as will appear from the description of the operation of the apparatus.

The pipe 55 connects with the casing of the heat exchanger 44 and is controlled by a valve 63. A pipe 64 also connects the lower part of the heat exchanger casing with the pipe 55, and the pipe 64 is controlled by a valve 65. The pipe 55 also has branch pipes 66 and 67 controlled by valves 66a and 67a and connecting with the tower 42 and the lower part of the still 41 respectively. Thus it will be seen that the heavier oils from the still 14 can be passed through the heat exchanger, where they will absorb, some of the heat from the hot coil in said exchanger, or the oils may be passed directly through the pipes 66 or 67, and the heat exchanger may be cut out so far as the heavy oils from the still 14 are concerned. The still 41 has a/drain pipe 68 from which the nal bottom oils may be drawn into the tank 69 or the like.

In order that the course of the various stocks may be under as complete controlas possible, I arrange a chamber 70 in the line 40, and connect this by means of a pipe 71 which is controlled by a valve 72 with the pipe line 55 at a point between the Valves 55b and 63, and I also connect these two valves to a pipe 73 which is controlled by a valve 74 and which leads to the pipe line 13, having a valve 7.5 near said pipe line, and the pipe 13 is also provided with a valve 76 between the pipe 73 and the still 14. Thus by manipulating the valves 75, 76, 72, 74, 55b and 63, the heavy oil from tank 10 may be passed directly to the second still 41 if desired, or the oil separating in the chamber 70 may be returned to the pipe line 13. This arrangement, it will be noticed, places the whole apparatus under easy control, to the end that both heavy oil bottoms. and cracking stock may be directed to practically any part of the apparatus.

The method and sequence of operations are as follows. A flow of crude oil is maintained into the still 14, and the contents are raised to the desired temperature by the furnace 15. The tops or light products pass off through the pipe 17, condenser 18, and pump 21 to the storage tank 23 for distillates. The intermediate or cracking oil passes out through the pipe 24, condenser 25, pump 28, and pipe 29, to the cracking stock tank 30. At the same time the ow of the bottoms from the still 14 is maintained through the pipes 53 and 55 to the still 41. The cracking stock which is passed from the still 14 is drawn from the tank 30 and forced by the pump 32 through the cracking apparatus 36, where it is superheated and cracked, and the mingled products of the cracking process pass at high temperature into the lower part of the still 41 where they are thoroughly mingled with the bottoms which have been pumped from the still 14. The introduction of these highly heated gases and products of the still 36 will ordinarily raise the products in the still 41 to a sufficiently high temperature for disdistillation, but if the conditions are such, or the bottom oils introduced in the still 41 are of such a temperature that additional heat is required, it can be supplied from the furnace 41a. Cracking now takes place in the still 41, and the tops or light products pass off through the pipe 43, heat exchanger 44, condenser 45, and gas tank 46, to the distillate storage tank 23.

The object of introducing the cracked material to the second still is primarily to causeA additional cracking in the heavy stock, and not necessarily for any benefit which may be derived from distilling these cracked materials, with the heavy products, although beneficial results may follow. The production of additional cracking by the method described has the advantage that the heat is transmitted to 'the still from the inside rather than from the iiue gases on the outside of the shell, thus simplifying the mechanical problem involved. The application of heat to the second still in which the cracked products are introduced should be only incidental, and the object would be to supply a small amount of heat to overcome radiation losses and bring the contents to as high a temperature as possible without attempting to crack them, which would endanger the shell of the still. The cracked vapors then would only add the additional amount of heat necessary to carry out the work.

The intermediate or cracking stock from the tower 42 passes out through the pipe 48, condenser 49, tank 50, pump 51, and pipe 52, to the cracking stock tank 30, where itis returned as already described to thestill 4l, and thus the operation is carried on in a substantially closed cycle, this being possible by the continuous introduction of new stock from the still 14.

It 4will be seen that the temperature of the still 41 can be very perfectly controlled by reason of the pipe connections described. If external temperatures are comparatively low or stock is being drawn from the tank 58, the bottoms from said tank can be passed through the heat exchanger 44, where the highly heated tops passing out through the exchanger will give up their heat to the' cooler bottoms passing to the still 41.

If on the other hand it is desirable to. cut out the heat exchanger and deliver the bottoms from the still 14 directly to the still 41, this can be done as already described by controlling the valves 63, 65, 66a and 67a.

In carrying out the process in the manner described, it will be seen that I get the natural ow of tops from the still 14 in the first instance, and

i parative ease.

It will be noted that the products of the cracking apparatus 36 divide, the heavier bottoms settling out, and the cracking products passing for.-

ward to the still 41, heating and thoroughly blending the contents of the still; and because of this, further distillation takes place, and as the heat is principally applied internally instead of externally of the still shell, there is a comparatively small deposition of carbon, and it will be further observed that I effect great heat economies because the products of the still 36 will heat to the distillation point theproducts in the still 4l., and no extraneous heat is normally necessary in the furnace 41a. Furthermore, it will be seen from the description that the superfluous heat from the tops of the still 41 passing through the heat exchanger 44, will be absorbed by the bottoms from the still 14 and the latter will be injected hot into the sti11.41.

It will be noted that the various pipe lines of the apparatus are valve controlled and arranged so that the various products can be given 'practically any desired course, and in some cases it may be desirable to cut out the still 14 and use the still 41 as a topping still, and operate it in connection with the cracking apparatus, 36, in which case the tops may be drawn off from the still 4l, the intermediate products circulated through the cracking apparatus 36, the bottoms separated out at the separator 38B, and the hot cracking stock injected into the body of the still 4l, from which the bottoms may be drawn as already described.

I claim:-

1. The method of treatingvliquid hydrocarbons to produce distillates of relatively low boiling points, which comprises first distilling oil the low boiling products in an independently fired still, then distilling off an intermediate product or cracking stock, leaving the high boiling products as an unvaporized residue or bottoms, cracking the cracking stock, blending the said bottoms and cracked stock in a second still, distilling off the tops or low boiling products and intermediate products or cracking stock from said second still, separately collecting said .tops and intermediate products, circulating the intermediate products or cracking stock from said second still through a cracking apparatus and back to said second still, and introducing a fresh supply of bottoms to the second still.

2. The herein described method of cracking oil which comprises subjecting the oil in an independent topping still to distillation to separate from the oil a low boiling product and an intermediate product or cracking stock leaving the high boiling products as an unvaporized residue or bottoms, passing the cracking stock to a heater wherein it is subjected to cracking, continuously blending bottoms from said topping still and the said heated cracking stock in a second still, distilling off in the latter still the top or low boiling products and intermediate products or cracking stock from the blended cracking stock and bottoms, separately collecting said tops and intermediate products, and subjecting the' latter cracking stock to cracking and discharging the resulting cracked products into said second still. j 3. An apparatus for cracking oil, comprising an independent still having means for taking off the lighter constituents, a cracking apparatus, a second still which is entirely independent of said first named still, means for discharging the unvaporized residue or bottoms of the rst still to the second still, independent means for taking off intermediate constituents or cracking stock from 'the first still and discharging it through the cracking apparatus to the second still, independent means for taking off intermediate constituents from the said second still, means for cracking the latter intermediate constituents, and means for discharging cracked products from the latter cracking means into said second still.

4. An apparatus of the kind described comprising a fractionating still having a discharge for the lighter constituents of oil distilled therein and a. separate discharge for the intermediate or cracking stock constituentsv of oil rdistilled therein, a second still which is entirely independent of said first named still having separate( means for discharging the lighter and intermediate or cracking stock constituents of oil distilled therein, a cracking still, means for discharging the bottoms of the rst still into the second still, and means for forcing the cracking stock from the said first and second independent stills through the cracking still and into the second still.

5. An apparatus of the kind described comprising a fractionating still having means for drawing off the lighter constituents and separate means for drawing oi the intermediate constituent or cracking stock, alsecond and independent fractionating still having separate means for'` the second still, and means for discharging the f intermediate or cracking stock from both of the said independent stillsthrough the cracking still and into the second still.

6. An apparatus of the kind described comprising a fractionating still having means for discharging the lighter constituents and separate means for discharging the intermediate constituents or cracking stock, a second still having means for discharging the lighter constituents, a heat exchanger to receive the lighter constituents from the second still, a crackingstill, means for discharging the intermediate constituents or cracking stock from the first still through the cracking still and into the second still, and a pipe connection whereby the bottoms of the rst still may be discharged through the heat exchanger in indirect heat exchange relation with the said lighter constituents passed thereto and into the second still.

'7. In an apparatus of the kind described the combination of the two stills each having means for discharging the lighter constituents; and separate means for discharging the intermediate constituents, a cracking still, means for passing the intermediate constituents or cracking stock from the stills through the cracking still and back to the .second still, a storage tank for the stituents, a cracking still, and means for passing the intermediate or cracking stock constituents from the stills through the cracking still and back to the second still, of a storage tank for bottoms, a heat exchanger through which the lighter constituents from the second still pass, and a valve controlled pipe connection between the first still, the storage tank, the heat exchanger, and the second still, whereby the bottoms of the rst still may be directed selectively to the storage tank, heat exchanger, or direct to the second still.

9. The combination of rst and second stills each still having means for discharging the lighter constituents, and means for discharging intermediate constituents or cracking stock, a.

cracking still, and means for circulating said cracking stock from the two stills through the cracking still and back to the second still, of a pipe line connecting the lower portions of the two stills, a by-pass in the pipe line connected to a storage tank for unvaporized oil or bottoms, a heat exchanger through which the lighter constituents fromv the second still pass, and means for directing the unvaporized oil or bottoms from the rst still selectively through the said heat exchanger or directly into the second still.

' 10. An apparatus for cracking oil, comprising a still, a second still, means for discharging the unvaporized oil or bottoms from the rst still to the second still, a heating and cracking apparatus having a separating chamber between the heating and cracking portions thereof, and means for discharging cracking stock from the rst still through the heating and cracking apparatus to the second still.

11. An apparatus for cracking hydrocarbons, comprisingv in combination a still having sep'arate discharges for distilled constituents and residues, a second still having a discharge for lighter constituents and a separate discharge for intermediate constituents or cracking stock, a preheating apparatus, a cracking apparatus, means for circulating said cracking stock from said second still through said preheating and said cracking apparatus and back to the said second still, means for passing residues from said rst still to said second still, means located between said preheating apparatus and said cracking apparatus for separating out the heavy oil, and means for adding distilled constituents from the rst still to the said cracking stockI from the second still.

12. An apparatus for cracking hydrocarbons, comprising in combination a still having separate discharges for distilled constituents and residues.a second still having a discharge for lighter constituents and a separate discharge for intermediate constituents or cracking stock,

means for withdrawing bottoms from said second still, a preheating apparatus, a cracking apparatus, means for circulating said cracking stock from said second still through said preheating and cracking apparatus and back to the said second still, means for passing residues from said first still to said second still, means located between said preheating apparatus and said cracking apparatus for separating out the heavy oil,

- and means for adding distilled constituents from the iirst still to the said cracking stock from the second still.

13. An apparatus for cracking hydrocarbons, comprising in combination, a still having separate discharges for distilledconstituents and residues, a second still having a fractionating column provided with a discharge for light constituents and a separate discharge for intermediate constituents or cracking stock, means for introducing residues from said first still into said column, means for withdrawing bottoms from said second still, a pipe still adapted to receive said cracking stock, a separating chamber into which said pipe still discharges, means for withdrawing heavy oil from said chamber, a cracking coil connected to said chamber and discharging into said second still, and means for adding distilled constituents from the rst still to the said cracking stock from the second still.

14. An apparatus for cracking hydrocarbons, comprising in combination a still having separate discharges for distilled constituents and residues, a second still, a dephlegmating column adapted to receive vapors fromvthe said second still and having a vapor outlet near its top for the lighter constituents and a separate intermediate discharge for intermediate constituents or cracking stock, means for introducing liquid residues from said rst named still into said column at a lower intermediate point thereof, means interconnecting said said second still and the lower portion of said dephlegmating column for passing liquid residue from the said column into the said second still, a cracking apparatus, means for circulating said cracking stock free from the heavier components of said liquid residues through the cracking apparatus and back to the said second still, and means for adding distilled constituents from the first still to the said cracking stock from the second still.

15. An apparatus for cracking hydrocarbons, comprising in combination a still having separate discharges for distilled constituents and residues, a second still, a dephlegmating column adapted to receive vapors from the said second still and having a vapor outlet near its top for the lighter constituents and a separate intermediate discharge for intermediate constituents or cracking stock, means for introducing liquid residues from said first named still into said column at a lower intermediate point thereof, means interconnecting said second still and the lower portion of said dephlegmating column for passing liquid residue from the said columnv into the said second still, a cracking apparatus, means for circulating said cracking stock free from the heavier components of said liquid residues .through the cracking apparatus and back to the said second still, means for adding distilled constituents from the iirst still to the said cracking stock from the second still, and means for withdrawing bottoms from said second still.

16. An apparatus for cracking hydrocarbons, comprising in combination an independent topping still having separate discharges for distilled vapors and residues, a dephlegmating column associated with said still and receiving therefrom said distilled vapors, a second and independent dephlegmating column having a vapor outlet near its top for lighter constituents and a separate intermediate discharge for intermediate constituents or cracking stock, means for introducing liquid residues from said topping still into said second-named dephlegmating column at a lower intermediate point thereof, a cracking apparatus, means for passing said cracking stock free from heavier components of said liquid residues through the cracking apparatus, means for passing the lighter vapors thus generated back to said second named dephlegmating column, and means for withdrawing products from said first named dephlegmating column and adding them to the said cracking stock from the said second-named dephlegmating column.

17. An apparatus for cracking hydrocarbons, comprising in combination an independent topping still' having separate discharges for distilled vapors and residues, a dephlegmating column associated with said still and receiving therefrom said distilled vapors, a second and independent dephlegmating column having a vapor outlet near its top for lighter constituents and a separate intermediate discharge for intermediate constituents or cracking stock, means for introducing liquid residues from said topping still into said second-named dephlegmating column at a lower intermediate point thereof, a cracking apparatus, means for passing said cracking stock free from heavier components of said liquid residues through the cracking apparatus, means for passing the lighter vapors thus generated back to said second named dephlegmating column, means for withdrawing products from said rst named dephlegmating column and adding them to the said cracking stock from the said secondnamed dephlegmating column, and means for eliminating residual bottoms from said dephlegmating column.

18. The method of treating high boiling point hydrocarbons to convert the same into hydrocarbons having relatively lower boiling points, which comprises distilling heavy oil charging stock in an independent distilling zone, passing resulting vapors to a dephlegmator to separate therefrom constituents suitable as cracking stock, feeding the said separatedfcracking stock constituents into a cracking apparatus, discharging the products resulting from cracking into a separating zone wherein cracked vaporous products are separated, passing the vapors intoa dephlegl mator, feeding residual stock from said distilling 40k L off light constituents as vapors and intermediate zone into said dephlegmator, separately drawing constituents free from the heavier components of said residual stock as cracking stock from said last named dephlegmator, and passing said cracking stock in liquid form tothe cracking apparatus.

`19. The method of treating high boiling point "hydrocarbons to convert the same into hydrocarbons having relatively lower boiling points, which comprises distilling heavy oil charging stock in an independent distilling zone, passing resulting vapors to a dephlegmator to separate therefrom constituents suitable as cracking stock, *feeding the said separated cracking stock constituents into a cracking apparatus, discharging the products resulting from. crackingr into a separating zonewherein cracked vaporous products are separated, passing thevapors into ya dephlegmator,

feeding liquid residual stock from s aid'distilling `zone into said dephlegmator, separately drawing' oif light -constituents as vapors and intermediate constituents free from the heavier components of l said residual stock as cracking stock from said last-named dephlegmator, passing said cracking stock in liquid form'to the said cracking apparatus,` and withdrawing heavy residues from said separating zone. y K

20. The method of rtreating high boiling point ,hydrocarbons to convert the same into hydrocarto a cracking apparatus, discharging the products resulting from cracking into a separating zone wherein cracked vaporous products are separated, passing the vapors into a second dephlegmator, feeding residues from said distilling zone into said second named dephlegmator, separately drawing off from said second dephlegmator light constituents as vapors and intermediate constituents free from the heavier components of said residues as cracking stock from said dephlegmator, passing said cracking stock from the second dephlegmator through the cracking apparatus, and passing vapors resulting from cracking back to the said second named dephlegmator.

21. The method of treating high boiling point hydrocarbons to convert the same into hydrocarbons having relatively lower boiling points, which comprisesl distilling heavy oil charging stock in an independent distilling zone, passing resulting vapors to a dephlegmator to separate therefrom constituents suitable as cracking stock, feeding the said separated cracking stock constituents into a cracking apparatus, discharging the products resulting from cracking into a separating zone wherein cracked vaporous products are separated, passing the vapors into a second dephlegmator above said zone, feeding residual oil from said distilling zone into said dephlegmator, separately drawing off light constituents as vapors and intermediate constituents free from the heavier components of said residual oil as cracking stock from said second dephlegmator, passing said cracking stock from the second dephlegmator ythrough the cracking apparatus, and withdrawing heavy residues from said separating zone.

22. The method of treating high boiling point hydrocarbons to convert the same into hydrocarbons having a relatively low boiling point which comprises distilling heavy oil stock in an independent distilling zone, passing vapors to a dephlegmator to separate therefrom constituents suitable as cracking stock, feeding the said cracking stock constituents into a cracking apparatus,

discharging the products resulting from cracking into a zone wherein more volatile constituents thereof are separated as vapors, maintaining a body of liquid in said zone, passing vapors from said zone into a second dephlegmator, feeding residual stock from said distilling zone into said second dephlegmator, separately drawing off from said second dephlegmator light constituents as vapors and intermediate constituents free from the heavier components of said residual stock as cracking stock, supplying external heat to said separating zone and passing said cracking stock from the second dephlegmator through the-cracking apparatus.

23`. The method oi treating high boiling point hydrocarbons to convert the same into hydrocarbons having a relatively low boiling point which comprises distilling heavy oil stock in an independent distilling zone, passing vapors to a dephlegmator to separate therefrom constituents suitable as cracking stock, feeding the said cracking stock constituents into a cracking apparatus, discharging the products resulting from cracking into a zone wherein more volatile constituents thereof are separated as vapors, maintaining a body of liquid in said zone, passing .vapors from said zone into a second dephlegmator, feeding residual stock from said distilling zone into said second dephlegmator, separately drawing off from said second dephlegmator light constituents as vapors and intermediate constituents free'from the heavier components of said residual stock as cracking stock, supplying external heat to said separating zone and passing said cracking stock from the second dephlegmator through the cracking apparatus and withdrawing heavy residues from said separating zone.

24. A process of converting higher boiling oils into lower boiling oils which comprises, passing a stream of liquid oil to a coil, heating said oil in the coil to effect cracking thereof, passing from said cracking operation the evolved vapors of lower boiling oils to a dephlegmator, simultaneously distilling a fresh crude oil in a topping still, passing evolved vapors therefrom to a dephlegmator, said dephlegmator being independent of said rst named dephlegmator,l introducing liquid residues from said topping still into said first named dephlegmator, removing light constituents of said fresh oil and said cracked vapors from the top of said second and first named dephlegmators,

respectively, and removing cracking stock freev from the heavier residual components of said fresh crude oil from each of said dephlegmators and passing thesame to said coil.

25. Process for the conversion by heat of a heavy heterogeneous mineral oil feed stock into gasoline and higher boiling point products comprising separating the more volatile from the less volatile constituents of the feed stock, subjecting said less volatile constituents to a cracking reaction and separating' a heavier fraction of the more volatile products of said cracking, mixing said heavier fraction with a heavier fraction of the more volatile constituents of the feed stock, separately cracking said mixture concomitantly with but under different conditions than said first named cracking reaction, and collecting the products of said cracking reactions which have a boiling point within the gasoline range.

26. Process for the heat treatment of mineral oils comprising as steps subjecting heterogeneous feed stock to heat, and separating the more volatile from the less volatile constituents, subjecting the less volatile constituents to cracking for conversion into more volatile constituents, separating a fuel oil fraction, a heavy condensate and more volatile constituents, returning the heavy condensate to the same cracking and subjecting the more volatile constituents of the results of the said operations to treatment including separate cracking of the less volatile fractions of the said more volatile constituents and separately collecting the products of higher and lower boilingpoint ranges.

27. Process for the heat treatment of mineral oils comprising as steps subjecting heterogeneous feed stock to primary heating by exchange with the eiilux from a cracking operation, and separating the more volatile from the less volatile constituents, subjecting the less volatile constituents to cracking for conversion into more volatile constituents, separating a fuel oil fraction, a heavy condensate and more volatile constituents, returning the heavy condensate to the same cracking and subjecting the more volatile constituents of the results of the said operations to treatment including continuous separate cracking of the less volatile fractions of the said more volatile constituents and separately collecting the products tions of the oil at an intermediate point in the heater, a mixing chamber of small capacity means for passing the hot cracked products from the heater to the chamber, means for concurrently supplying fresh uncracked charge'to the chamber, a distillation chamber of large capacity directly and openly connected to the mixing chamber and adapted to receive all of the products therefrom, and a fractionating column in vapor connection with the distillation chamber and adapted to fractionate the vapors evolved therefrom between motor fuel and heavier oils.

29. A method of cracking and distilling hydrocarbon oils which comprises heating a selected distillate cracking stock to a cracking temperature under pressure in transit through a cracking coil where cracking takes place, delivering the cracked products into an enlarged chamber where cracking and distillation occur, withdrawing the evolved vapors from said chamber, subjecting said vapors to fractionation, removing the lightest vapors for condensation and collection, returning the heaviest constituents to the chamber for further treatment therein, removing the in,-- termediate constituents and delivering them unmixed with other stock to constitute the selected distillate cracking stock for said cracking coil, delivering relatively cool fresh charging oil into the zone of fractionation at a point below the removal of the intermediate constituents therefrom to distill olf the lighter constituents of the charging oil while the heavier constituents thereof are passed into said chamber, and delivering another portion of said relatively cool fresh charging oil into said chamber to effect a partial cooling of the hot products therein while subjecting the charging oil to cracking and distillation therein.

30. The method of treatingv liquid hydrocarbons to produce distillates having relatively low boiling points, which comprises subjecting oil to cracking, withdrawing cracked vaporous products and passing them to a dephlegmating zone, separately withdrawing from said dephlegmating zone a fraction containing desired low boiling products and another fraction containing higher boiling products suitable as stock for said cracking operation, passing said high boiling products to said cracking operation for retreatment therein, subjecting heavy oil charging stock to distillation in a distilling zone, which is independent of said cracking zone, to vaporize in part the said heavy oil, passing the distilled vapors to a second and independent dephlegmating zone, separatelylao withdrawing and collecting lower boiling dephlegmated vapors from the latter dephlegmating zone, separately withdrawing from the latter de#- phlegmating zone a fraction containing higher boiling products suitable as charging stock for said cracking operation, and supplying such higher boiling products to the said cracking operation separately withdrawing unvaporized residual products from said independent distilling zone and directly contacting them with the aforesaid cracked vaporous products after their withdrawal from said cracking operation and prior to their passage to said first-named dephlegmating zone to vaporize and thereby distill additional constituents of said residues and cause said vapors to undergo dephlegmation in admixture with the said cracked vapors.

31. The method of treating hydrocarbon oil to produce lower boiling products therefrom which comprises heating in an elongated restricted pas- 150 roo sageway a. flowing stream of oil to cracking temperature and subjecting it to cracking, discharging resulting cracked products into an enlarged separating zone, separately withdrawing vapors from said separating zone and passing them to a dephlegmating zone, separately withdrawing from the dephlegmating zone a fraction comprising desired low boiling products, separately withdrawing from the latter zonel a fraction comprising higher boiling constituents, passing the latter higher boiling constituents to said restricted passageway for additional cracking treatment, subjecting heavy oil charging stock to distillation in a distilling zone, which is independent with respect'to said cracking zone, to vaporize in part the said heavy oil, vpassing the distilled vapors to a second dephlegmating zone wherein they are subjected to dephlegmation in the absence of the aforesaid cracked vaporous products, separately withdrawing from the said second dephlegmating zone a lower boiling dephlegmated fraction, separately withdrawing from the said second dephlegmating zone higher boiling fractions suitable as cracking stock and charging them to said elongated restricted passage for cracking treatment in the system, and withdrawing unvaporized residual products from said independent distilling zone and introducing them into said separating zone.

32. The method of treating hydrocarbon oil to produce lower boiling products therefrom which comprises heating in an elongated restricted passageway a flowing stream of oil to cracking temperature and subjecting it to cracking, discharging resulting cracked products into an enlarged-separating zone, separately withdrawing vapors from said separating zone and passing them to a dephlegmating zone, separately withdrawing from the dephlegmating zone a fraction comprising desired low boiling products, separately withdrawing from the latter zone a fraction comprising higher boiling constituents, passing the latter higher boiling constituents to said restricted passageway for additional cracking treatment, subjecting heavy oil charging stock to distillation in a distilling zone, which is independent with respect to said cracking zone, to vaporize in part the said heavy oil, passing the distilled vapors to a second dephlegmating zone wherein they are subjected to dephlegmation in the absence of the aforesaid cracked vaporous products, separately withdrawing from the said second dephlegmating zone a lowerboiling dephlegmated fraction, separately withdrawing from the said second dephlegmating Vzone highe boiling fractions suitable as cracking stock and charging theml to said elongated restricted passagel for cracking treatment in the system, and withdrawing unvapor-` ized residual products fromv said independent distilling zone and introducing them into said separating zone and collecting said residues in a body in said separating zone and maintaining them therein at cracking temperature.

33. The method oftreating hydrocarbon oil to produce lower. boiling products therefrom which comprises heating in anelongated restricted passageway a owing stream of oil to cracking temperature and subjecting it to cracking, discharging resulting cracked products into an enlarged separating zone, separately withdrawing vapors from said separating zone and passing them to a dephlegmating zone, separately withdrawing from the dephlegmating zone a fraction comprising desired low boiling products, separately withdrawing from the latter zone a fraction comprising higher boiling constituents, passing the latter higher boiling constituents to said restricted passageway for additional cracking treatment, subjecting heavy cil charging stock to distillation in a distillinglzone, which is independent with respect to said cracking zone, to vaporize in part the said heavy oil, passing the distilled vapors to a second dephlegmating zone wherein they are subjected to dephlegmation in the absence of the aforesaid cracked vaporous products, separately withdrawing from the said second dephlegmating zone a lower boiling dephlegmated fraction, separately withdrawingl from the said second dephlegmating zone higher boiling fractions suitable as cracking stock and charging them to said elongated restricted passage for cracking treatment in the system, and withdrawing unvaporized residual products from said independent distilling zone and introducing them into said separating zone wherein they are collected in a body and are distilled mainly by the aforesaid cracked products discharged thereinto, and withdrawing residues of said body and discharging them from the system.

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34. The method of treating hydrocarbon oil to produce lower boiling products therefrom which comprises heating in an elongated restricted passageway a flowing stream of oil to cracking temperature and subjecting it to cracking, discharging resulting cracked products into an enlarged separating zone, separately withdrawing vapors from said separating zone and passing them to a .dephlegmating zone, separately withdrawing from the dephlegmating zone a fraction comprising desired low boiling products, separately withdrawing from the latter zone a fraction comprising higher boiling constituents, passing the latter higher boiling constituents to said restricted passageway for additional cracking treatment, subjecting heavy oil charging stock to distillation in a distilling zone, which is independent with respect to said cracking zone, to vaporize in part the said heavy oil, passing the distilled 12 vapors to a second dephlegmating zone wherein they are subjected to dephlegmation in the absence of the aforesaid cracked vaporous products, separately withdrawing from the said second dephlegmating zone a lower boiling dephlegmated fraction, separately withdrawing from the said second dephlegmating zone higher boiling fractions suitable as cracking stock and charging them to said elongated restricted passage for cracking treatment in the system, and withdrawing unvaporized residual products from said independent distilling zone and introducing them into said separating zone wherein they are collected in a body and are distilled and maintained at a cracking temperature mainly by the aforesaid cracked products discharged thereinto, and withdrawing. residues of said body and discharging them from the system.

. LUIS DE FLOREZ.

CERTIFICATE 0F CORRECTION.

. men: Nb. 1,962,235. June lz, 1934.

LUIS de FLOREZ.

It is hereby certified that error appears in the printed specification of the `above numbered patent requiring correction as follows: Page 3, line 109, claim 5, for the syllable "ent" read ents; page 4. line 99, claim 14, strike out the word "said" second `occurrence; page 6, line 136, claim 30, strike out the c after"operation" and insert the same after "operation" in line 137; and that the said Letters Patent should be read with these' corrections therein that the same my conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of August, A. D. 1934.

Leslie Frazer {Seal) Acting Commissioner of Patents.

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