US1976507A - Manufacture of low boiling petroleum distillates - Google Patents

Description

Oct. 9, 1934, A. MCD. McAFl-:E

MANUFACTURE OF LOW BOILING PTROLEUM DISTILLATES File-d Jan.

Ursi @COU G 0 In/manto@ anneau-f KMMAFEE Kvmwm Patented Oct. 9, 1934 UNITED STATES MANUFACTURE F LOW BOILING PETROLEUM DISTILLATES Almer McDuflle McAfee, Port Arthur, Tex., as-

signor to Gulf Reiining Company, Pittsburgh, Pa., a corporation of Texas Application January 15, 1932, Serial No. 586,804

' 24 Claims.

' This invention relates to manufacture Yof low boiling petroleum distillates,'and it comprises a process of distilling higher boiling .petroleum hydrocarbons, advantageously containing a substantial proportion of hydrocarbons of a naphthenic type, with the aid of anhydrous aluminum chloride, in which the said higher boiling hydrocarbons are first heated to just below cracking temperatures, are then mixed with a magma of aluminum chloride and oil of substantially constant composition and areA c ontin.- uously charged into a lower section of a body of heated oil contained in a 'heat insulated conversion chamber, the resulting low boiling distillates being condensed in a constricted zone in the presence of a dilute alkaline solution, the pressure, temperature and proportion of aluminum chloride in said conversion chamber being such as to keep the aluminum chloride and oil in liquid phase, to convert the said higher boiling hydrocarbons completely into the said low boiling distillates, cokev and gases, and to hold the level of oil in the conversion chamber substantially constant; it also comprises a method of cooling and removing aluminum chloride coke from a conversion chamber in which method cool oil is used to displace the hot oil remaining in said chamber at the conclusion of a conversion run, water is employed to displace the said cool oil, the said water serving to disintegrate the said aluminum chloride coke, and the coke is substantially flushed from said chamber by water before the said chamber is opened to lthe atmosphere; and it also comprises certain organizations of apparatus elements suitable for feeding the said aluminum chloride magma and for carrying out the described process; all las more fully hereinafter set forth and .as'claimed As is well known, anhydrous aluminum chloride has several specific reactiosl upon heated.

mineral oils. One of the best known of these reactions is a conversion of higher boiling hydrocarbons into lower boiling distillates. This process is most frequently employed on high boiling distillates, and the resulting lower boiling ydistillates are known to be sweet smelling, saturated and stable. Various methods have been proposed to carry out this process, most of which have certain disadvantages. There are many diilicult problems involved in carrying out such processes, several ofl which have never been satisfactorily Asolved heretofore.

I have found it advantageous to heat the oil, which is to be converted, to temperatures just -below those required for thermal cracking and to mix this heated oil in a flowing stream with aluminum chloride just before passing the mixture into a heat-insulated conversion chamber. .It is advantageous yto introduce this mixture at the bottom of the conversion chamber rather than at the top. A somewhat higher yield is obtained and stirring in the conversion chamber i is obviatcd, the latter always having been a troublesome and expensive operation.

It has also been found that, by correlating the temperature of the heated oil in the conversion chamber with the amount of aluminum chloride added, a substantially constant level of oil may be maintained in the conversion chamber.' even though the heated oil-aluminum chloride mixture is introduced at a constant rate.

A convenient method of adding. aluminum chloride to heated oil has also been found. This consists in preparing a magma of aluminum chloride and oil by mixing the two, with the aluminum chloride in excess, at temperatures in the neighborhood of 150 to 200 F, and adding this magma to the heated oil by displacing the magma with an equal quantity of oil, the latter being thereafter employed to make up a new charge of magma. 'Ihe magma prepared in this manner has been found to have a fairly constant composition of 80 per cent aluminum chloride and 20 per cent oil. Its composition is so constant, in fact, that Weighing of the aluminum chloride,may be obviated, the volume of the magma added being a sulhcient index of the Weight of the chloride contained therein.

lt has also been found advantageous to spray an aqueous caustic solution into the distillate vapors coming from the conversion chamber just prior to introducing them into a condenser. This procedure prevents corrosion in the condenser coils. The caustic solution can be readily soA separated from the condensed low boiling disfrom crude oils in which the so-calld naph- '105 thenic type of hydrocarbons predominates.

The charging stock used with the best resul thus far has the following tests: l

Gravity: A.P. I 1 31-33 Over point: "F" 365 End point: F 650 l Per cent at 392 F 10 590 v90 50% at: F 467 Acid heat: F 2

Sulphur, (L): per cent l :0.2'

The gasoline produced from this type of charging stock by this inventionhas a low gum content and an exceptionally high anti-knock. value.

A gasoliney containingless than 4 mgs. of gum and having an octane number above 74 can be readily obtained. These characteristics set this particular gasoline apart from gasolines in general and render it especially suitable as fuel for aeroplane motors. It may be said that there is types to. produce a gasoline with intermediate 15 anti-knock values.

Other features of the present invention can be described more easily by referring to the accompanying drawing in which the figure represents,

more or less diagrammatically, certain organizations of apparatus elements within the purview of the present invention and useful in the performance of the described process. In this showing the single gure represents a diagrammatic, elevational view of the apparatus of th invention, partly in section.

'Ihe main elements of the lorganization of apparatus shown in the gure comprise a tubular heater 2 ilocated within a furnace 1, an aluminum chloride magma make-up tank 6an oil cylinder 8, two magma cylinders 9 and 10, a heat insulated converter or reaction chamber 14, a condenser 20, a distillate receiver 22, and

- a dilute caustic make-up tank 25. All of these -holes 15 and 16.

elements are inter-connected by suitably valved pipe lines in which are located the necessary pumps, etc. Y

The furnace 1 may be supplied with suitable heating means as at A-A. The tubular heater 2, located in this furnace is connected through line 3 and pump 4 to an oil supply line 5 which in turn is connected to a source (not shown) of dryA oil to be converted. Below the furnace 1 in the figure there is illustrated diagrammatically an aluminum chloride make-up tank 6, provided with stirrer 39, in which tank the magma or sludge of aluminum chloride and oil is prepared.

'I'his make-up tank is connected tothe oil line 32 by means of valved connection 7 and also to' both the bottom and top of two magma cylinders 9 and 10 by the valved lines 44'and 46, respectively. The exit 12 .of the magma cylindersfand the exit 11 of the tubular heater 2 unite at the 4way connection 28 which leads to the charge line 13 of the converter or still 14.

The converter 14 is provided' with two man- At the bottom there is a valve 17 which may be opened for cleaning out purposes. The converter is also provided with coke line 33, credit oil line 31, water line 34, safety valve 36, try cock 30 and vapor line 18, on which is connected gauge 37. The vapor line 18 connects, through a pressure reducing valve 19, with the condenser 20 in which is located the condensing coil 38. The vapor line is also connected, just before entering the condenser, with a dilute caustic line 21. All these connections are provided with suitable valves.

The exit of the condensing coil 38 is connected to a receiving tank 22. This receiving tank has a connection 47 from` which the disu tillate may be pumped to the usual steam stills (not shown) for producing gasoline. AA top 'connection`48 is provided for removing gases up tank 25.. The pump 29, connected to the exit of the caustic make-up tank is designed to deliver the dilute caustic either to the top. 'of the condenser coil by means of line 21 or to the bottom of the still through caustic line 40 and charge line 13.

Coke pump 27 is attached to the bottom of the converter by coke line 33 and to a point near the top of the converter by credit oil line 31. Line 26, connected to the discharge side of this pump leads to coke bins by branch 50 and to credit oil storage by branch 51. Credit oil storage is in turn connected to dry oil line 5` by lconnections not shown. Pump 27 may thus be used for pumping credit oil or coke to stor-4 age as well as for cooling the converter as hereinafter described.

When in operation the apparatus described is used as follows: Dry oil to be converted enters the oil line 5 and is pumped through the tubular heater 2, leaving through the line 11 at a temperature varying between 600 and 750 F., but advantageously close to 750 F. At the four-way connectionl 28, this hot oil meets the magma of aluminum chloride and oil which is continuously pumped from the magma cylinders 9 and 10. 'I'he resulting mixture enters the converter 14 through the charge line 13 at the bottom. 'I'he vapors leave through the vapor line 18 at the top of the converter and pass through the. releasing valve 19 which is set at about 150 pounds gauge pressure. At this point the vapors, now at about 50 poundspressure, meet a spray of a dilute caustic, such as -a caustic soda solution, supplied through the line 2l and pump -29. The vapors are condensed in the coil 38 and collect` with the dilute caustic in the receiver 22, the distillate being thereafter sent to steam stills for the production of gasoline.' The dilute caustic solution is separated by gravity from the distillate in the receiver, being drawn off through line 23 and returned to the make-up ta`nk 25, Where it is reconstituted from' time to time. Liquid caustic is added to this tank 'at 53. The proper setting of the valvesr in the variouspipe lines for carrying out the above operations is obvious from the drawing.

In the above process the proportion of aluminum chloride to the hot oil and the temperature of the latter are correlated in such a manner that the level of the oil in the converter remains substantially constant, for example at about the level of the try cock 30. If the level rises above this point, valve on line 31 may be opened and the oil run to credit through pump. 27 and lines 26 and 51. 'I'he loss vof any substantial amount of oil to credit means that the temperature and the proportion of aluminum chloride are not properly correlated. If the temperature or the proportion of aluminum chloride is raised slightly the tendency of the oil level to rise is immediately corrected. It is frequently convenient to regulate the temperature and the proportion of aluminum chloride in such manner that in each run there is a small but rather definite volume or oil run to'credit. 'I'his serves to keep the conditions of the reaction on the safe side, so to speak.

The hot oil and aluminum chloride, in the above operations, are passed `into the converter continuously until the coke which gradually builds up from the `bottom has displaced .nearly three fourths of the usual volume of oil. At

cooling .period itself occupying only to 12 ,'hurs. The development ofY emcient, safe and time saving methods for cooling the converter and for removing the coke represents one of the most diillcult problems encountered in the successful operation of an aluminum chloride pressure still. Corrosion is difficult to avoid and practically prevents the use of steam for cooling purposes, due to the release of hydrochloric acid by chemical reaction between the steam and the aluminum chloride coke. The coke in such a still frequently weighs 40,000 pounds. Any purely mechanical method of removing such a large mass from a confined space is bound to be dimcult, time consuming and expensive. These dimculties have been overcome in a .novel manner.

The cooling operation is carried out by shutting off the supply of hot oil and aluminum chloride to the converter and, by a suitable setting of the valves in the various pipe lines, introducing a flow of cool oil into the bottom of the converter byl means of pump 4, branch pipe 32 and charge pipe 13. This cooling oil passes out through the vapor line at the top of the converter, runs through condensing coil 38, where it is cooled, thence to oil line 41, and is finally sent by pump 27 to credit oil storage where it may be again picked up by pump 4 and recirculated. 'Ihe cooling oil is passedv through the converter in this manner until the latter is cooled below 212 F. 'I'hen dilute caustic from make-up tank 25 is introduced into the bottom of the converter by means of pump 29, dilute caustic line 40 and charging line 13, the valves on these lines being properly adjusted for this circulation. The caustic, solution displaces the oil upwardly and when it reaches the reducing valve 19 its flow is stopped. This caustic immediately neutralizes any hydrochloric acid which forms upon contact of the aluminum chloride coke with the solution.

The caustic solution in contact with the aluminum chloride coke rapidly disintegrates the same. Within about 3 hours the coke is reduced to a soft pulp. At this time water is introduced at a pressure of about 100 pounds through the water pipe 34, the coke and Water being removed by the coke line 33 and coke pump 27. Lines 26 and 50 deliver the coke to storage bins. After removal of the coke, the uppermanhole is opened and the water drained out of the converter at the bottom. A hose may be introduced through the lower manhole 16 in order to wash down any remaining coke. The valve 17 may be opened during the ilnal cleaning and draining operations. After inspection, the converter is then .ready for another run.

It will be noticed that, in the above cooling and coke removing operations, vthe conversion chamber is always full of liquid and is closed to the air until the aluminum chloride vcoke has been substantially removed from the chamber. It is well known that opening the chamber before this point is a highly dangerous operation. Considerable heat is generated upon the first contact of water with aluminum chloride coke and, when this contact takes place in the presence of air and oil vapors, fires and explosions are dimcult to prevent. The safety .factor of the above described cooling process is an important factor in promoting its use.

At the start of a converting run the converter is cool and wet from washing out and removing the coke of a previous run. To commence a run the furnace 1is fired and dry hot oil is introduced into the bottom of the converter through lines 11 and 13. The reducing valve 19 is left open and the hot oil soon evaporates all water which is driven od as steam* and condensed in the coil 38. When the converter is thoroughly dry the reducing valve is closed. Hot oil is forced.

through the-converter, (any excess being run to credit storage through line 31) until the pressure in the converter rises to about pounds. At this time the oil fed to the converter is carefully regulated both as to rate of ow and temperature. The flow of aluminum chloride magma is then commenced in carefully regulated proportions. v'I'he pressure in the converter at this point rapidly rises to the value set on the pressure reducing valve 19." Just before this valve opens the flow of caustic is started through the condenser coil by line 21 and pump 29. Then, as soon as the increasing `pressure forces open the reducing valve, the run is started.A

In one specific embodiment of the invention, which represents an actual commercial operation, a solar oil from a Texas coastal crude was fed at a temperature of about 750 F., to a 40 foot converter at a rate of about 35 barrels per hour. The aluminum chloride magma, prepared at a temperature of 200 F. and containing about 9 pounds of aluminum chloride per gallon, was y fed at a rate of 20 gallons per hour. A pressure of 150 pounds was maintained in the converter. This particular run was continued 72 hours.

The run was then stopped for cleaning the conl This distillate was transferred to steam stills for the recovery of its gasoline content while the bottoms from the steam stills were returned to charging stock. The gasoline producedv in this manner was sweet smelling, stable, saturated and had low gumand a high anti-knock value. It showed the following tests:

Gravity: A. P. I 61.5 Color, Saybolt +25 Doctor O. K. Sulphur: percent 0.015 Copper strip test: 122 F Good Gum and corrosion Mg. per 100 cc 2 Appearance O. K. Acid heat: "F 6 Motor fuel test E. G. corp. method: 212

F. octane No Themagxna `of aluminumy chloride and 'oil" `used"in-the"above"described processes is pre pared-in the make-up tank 6`, at a slightly ele'-l vated` temperature;

hole'42."At`tlie startof an operation oil `is run into this tank through line When the oil' and aluminurri"chloride` are' thoroughly mixedl the magma cylinders are-filled.`

In order to f ill magma cylinder 9, pump 43 is" started.` Valves` 54 and V55 are then opened.'

The magma isithus pumped intoV thebottom of the cylinder 9, any vair or oil which may be left- 4in thecylinderfrom a previous' operation being i displaced upwardly and flowing to credit through valve 63 o r into the 'make-up tank .6 through" valve 64. To ll magma cylinder '10, valves 56 'and Y5f? are similarly opened while pump 43"is" operating.

The magma from thesecylinders may be fed 'into and mixed with the hot oil from line llas `fo1lows:` The 'oil cylinder` 8 fmay rs't be filled by' opening' valvey 58 at the bottom ofthis cylinder;

This allows oil from llines 32fand 49 to flow into and 'fill the cylinder, since itis suitably vented to" the air at thetopl. Then with valves `54, 55 j and 58 closed andwith 'valves 65, 59`and 60`open,

the Iproportioning pump- 45 is started. This pumps oilfrom cylinder 8 into the 'top of magma- `cylinder 9.' 'This displacs the'magma contained in the .latter cylinder downward and into line 12 from which it ows tothe 4-way connection 28 ljoining the supply of hot oil from line 11 at this point and ows into the converter 14 through charge line 13. f

When the oil cylinder is emptied bythe pump 45 it is then known that all the magma in the magma cylinder is discharged sincethe volumes of the three cylinders 8, 9 and 10 are equall' At this pointvalve 58 may be again opened temi porarily which quickly lls the oil cylinderagain. i Valves 6l and 62 are opened while valves 59 and 60 are closed. As soon as the oil cylinder is filled, valve 58 .is closed. 'I'he oil in .this cyl'- inder now displaces the magma in .cylinder 10 downwardand into line 12s While this cylinder is being emptied-into jthe'convertenmagina cylinder 9may be refilled with-magma. .This -isf accomplished as outlinedpreviously, the oil used.

" numnloride boils aujabout 500 .F. 1f these temperatures and pressures are increased, the

for displacing the magmain the previous operation being displaced upwardly and run to credit through valve 63, with valve 64 closedfor 'it may be run into the make-up tank. 6 through valve 64, Where it may be used as fresh oil for making up additional magma.

It is thus evident that, by using the manipulations described, the three cylinders, Sand 10 can be employed to feed magma into the converter continuously. The oil in cylinder 8 acts' as a fluid piston in displacing the magma from cylinders 9 and 10. An important feature of 'I'he anhydrous aluminmchloride is added tot-his tank through the man--y -portioningpump willdeliver anaccurate quantity of oil it cannot be'used successfully over` an extendedfperiod 'to, measure and pump magma. The latterfis too viscous and theabrasion caused by the aluminum chloride greatly reduces the life of such a` pump. yIt isfalmost impossible ftd keep this .typefof pump` in good working order lwhen delivering magma. Thus both pump'and gauging difiiculties have been c elir'ninated'- by thefsi'mple, expedient of forcing the magmauinto the'vconver'sion drum Vby downward displacement withoil.y

When the Atemperature of the aluminum chloride 'magma in the'make-up tank'is maintained constantand within aral'gtfof from 156? to 200" F., its .composition vis kre'rriarkably constant. When` the temperature is maintained at Iabout 206?y F., for example-itseomposition is approximately perl cent aluminumM chloride and,20 per cent oil. A galloncontainsaboutiQ pounds of aluminum chloride. The(weightof the. alunr'lin'umf` chloride, in such .a magma 4need netbe, determined, the volume of .the 'magma .being a sufficient index of 'the weight of the chloride contained therein. Any variations Lin the composition are readilydetected by thetendency; of the' oil level vin they converterto rise or fall.A If `this levelv remains constant itis obviqus that the'aluminurnchloride "isfcor- .rectly adjusted.. The level can, inf4 fact, .be

maintained gunst-ant by adjustment: tpe-reta.

Whe'n this is done the oil 4fedilito the converter is allconverted into distillate, lcokeand socalled permanent "gases', aj balanced condition which is highly desirable'.

Itjhasbeen found that lthe hydrogen chloride and hydrogen sulfide developed in the'converter do not-"causean'y Vs1`1b`stai-1tial'- corrosion. until they` reach the condens erv coiland that Athis cor'- rosion can' be 'effectively obviated by. spraying dilute caustic in tofths coil -as-'described'prev iously.'` This 'i s an" .extremely simple method'of removing -thisl source' of annoyance 'and expense. The specific conditions-of; operation outlined @above 'may bevaried to a considerable extent Without departing from the purview of the -i'n-i vention. For example,v` the pressures employed i'n the process can be varied ysornev'vhat but are advantageously maintained somewhat above the pointatwhich sublimation 4 of aluminum chloride occ'i'irs.4 The oil, must'also b e maintainedin liquidphase` by pressure. Thereaction used in this `invention apparently does not occur inthe vapor phase, `and hencev vit is advantageous to prevent volatilization of the chloride.

Whilefa satisfactory distillate is obtained by distillation of oilwith aluminuxr'i chloride at atm'osphe'ric pressure, the yc oin/"ersif'm `is slow and theyield'poon `The mixture of eiland-alumitime vof conversion may-be shortened to afjfew minutes and the yieldii'ncreased 200 to 300 per 'centi' 'In'the abovedescribed process pressures "have been' found advantageous, while a suitable oilv charged, vas used in the above specicexamv p'le. is about 5 pounds perbarrel (1.6 percent by weight) This proportion maybe varied beiso tween about 5 and 7 pounds per barrel (1.6 to 2.3 per cent by weight). Somewhat above 1 per cent or about 2 per cent is usually suflicient. As mentioned previously however, this quantity is advantageously correlated with the temperature of the hot oil in order to maintain a substantially constant level of oil in the converter. Temperatures ranging between 600 and 750 F. may be employed for the heated oil. These temperatures are somewhat below those required for thermal cracking. If the temperature is allowed to go high enough to cause thermal cracking, aluminum chloride appears to change its role from a converting to a polymerizing agent. Such temperatures are not ordinarily useful in the above described process.

The alkaline solution employed in washing the distillate vapors may be the same as that used for disintegration of the coke. Practically any dilute alkaline solution is suitable. Caustic soda solution with a concentration of about 3 to 4 per cent is advantageous. Caustic potash, sodium phosphate and soda ash solutions etc. are applicable. -Milk of lime can be used if desired.

In the claims, the term aluminum chloride refers to anhydrous aluminum chloride.

What I claim is:

1. In the manufacture of low boiling distillates from higher boiling hydrocarbon oils, the process which comprises heating said higher boiling oils tc temperatures slightly below those required for thermal cracking, adding somewhat above 1 per cent of aluminumehloride to the heated oils, feeding the mixture in a stream into a reaction zone containing a body of hot oil mixed with aluminum chloride, and there, without supplying additional heat thereto converting said mixture into distillate and coke and permanent gases at a rate corresponding to the rate of feed and allowing coke to build up in the said reaction zone; while the reaction zone and the point at which aluminum chloride .is added are maintained under suflcient pressure to prevent sublimation of aluminum chloride and to keep the bulk of the unconverted oil in liquid phase.

2. The process of claim 1 in which the higher boiling hydrocarbon oils contain a substantial proportion of hydrocarbons of a naphthenic type.

3. The process of claim 1 in which the aluminum chloride added to the heated oils varies between 5 and 7 pounds per barrel of oil charged.

4. The process of claim 1 in which the aluminum chloride added to the heated oils amounts to about 2.0 per cent.

5. The process of claim 1 in which a pressure ranging from 75 to 300 pounds persquare inch is.maintained in said reaction zone and at Ithe point where aluminum. chloride is introduced.

6. The process of claim 1 in which the higher boiling oils are heated to a temperature between about 600 and 750 F.

7. The process of claim 1 in which the higher boiling oils are heated to a temperature of about 750 F.

8. In the manufacture of low boiling distillates from higher boiling hydrocarbon oils. the process which comprises heating a flowing stream of said higher boilimg oils to a temperature in the neighborhood of 750 F., adding about 2.0 per cent of aluminum chloride to said flowing stream of heated oils and allowing the mixture to react in a reaction zone to produce coke, distillate and gases under a pressure of about 150 pounds per square inch, while neither supplying additional heat to nor withdrawing Acoke from the said reaction zone.

9. In the removal of coke from an aluminum chloride converter, the process which comprises cooling the converter below 212 F. by displacement with cooling oil, displacing the cooling oil with a dilute alkaline solution and then drawing off and washing out the resulting coke pulp.

10. In an apparatus for making and feeding in'a continuous stream a magma of aluminum chloride and oil, the combination of a magma make-up tank with an oil cylinder and two magma cylinders, the said.' magma cylinders being connected at both bottom and top to said make-up tank and the bottom of said oil cylinder being connected to the tops of said magma cylinders.

11. In the manufacture of low boiling distillates from higher boiling hydrocarbon oils, the process which comprises heating said higher boiling oils in a liquid flowing stream to temperatures slightly below those required for thermal cracking, adding somewhat above one per cent of aluminum chloride to the heated oils, feeding the mixture into a reaction zone maintained under pressures suflicient to prevent sublimation of aluminum chloride and to which no heat is supplied, and there substantially entirely converting` said mixture into distillate, coke, and permanent gases, while not withdrawing any coke from the reaction zone.

12. The process of claim 11 in which a pressure ranging from 75 to 300 pounds per square inch is maintained over the said body of hot oil.

13. The process of claim 11 in which the higher boiling oils are heated to a temperature between about 600 and 750 F.

14. In the manufacture of' low boiling distillates from higher boiling hydrocarbon oils, the process which comprises beating said higher boiling oils in a flowing stream under high pressures to temperatures slightly below those required for thermal cracking, adding a small amount of aluminum-chloride to the heated oils, feeding theV mixture into a reaction zone maintained under a pressure within the range from about 75 to 300 pounds per square inch and at a temperature not exceeding '150 F. and there continuously and substantially entirely convertingsaid mixture into distillate, coke, and permanent gases, while not withdrawing any coke from the reaction zone.

15. The process of claim 14 in which a pressure ranging from 75 to 300 pounds per square inch is maintained over the said body of hot oil.

16. The process of claim 14 in which the higher boiling oils are heated to a temperature between about 600 and 750 F.

17. In the manufacture of low boiling distillates from higher boiling hydrocarbon oils, the process which comprises heating said higher boiling oils in a flowing stream under high pressures to temperatures slightly below those required for thermal cracking, adding somewhat above one per cent of aluminum chloride to the heated oils, feeding the mixture into a reaction zone maintained at a pressure above about 75 pounds per square inch, said reaction zone con'- taining a body of oil and aluminum chloride, the mixture being fed into said reaction zone at a rate to maintain the level of said oil and aluminum chloride therein substantially constant, and there continuously and substantially entirely converting said mixture into distillate, coke, and

y above one per cent of aluminum chloride to the heated oils,` feeding the mixture into a reaction' zone maintained at pressures suiciently high to prevent sublimation of aluminum chloride without additional heat being supplied thereto, allowing conversion to take plac'e in said reaction zone without agitation other than that supplied by the flowing stream of oil and without withdrawal of aluminum chloride coke, thereafter stopping the flow of the said mixture, reducing the coke to a pulpy mass by passing water into said reaction zone and then flushing out said pulpy mass.

19. In the conversion of high boiling petroleum oils into lower boiling petroleum oils, the process which comprises heating said higher boiling oils in a flowing fstream to temperatures slightly below those required for thermal cracking, discharging the oil into a reaction zone maintained at pressures above pounds per square inch and at temperatures not substantially exceeding 750 F., said reaction zone containing a body of oil and aluminum chloride, the i mixture being fed into said reaction zone at a rate to maintain the level of said body therein substantially co'nstant, continuously adding aluminum chloride to the heated oilin such quantity as will effect substantially complete conversion of thel heavier oils to lower boiling distillate, coke and gases and will simultaneously effect maximum exhaustion of the aluminum chloride, and not removing spent aluminum chloride during the oil conversion step.

20. In the conversion of high boiling petroleum oils into lower boiling petroleum oils, the process to the heated' foil in such. quantity as will effect' substantially complete conversion of the heavier oils to lower boiling distillate, coke and gases and will simultaneouslyeffect maximum exhaustion of the aluminum chloride, and not removing spent aluminum chloride during the oil conversion step, continuing said oil conversion without agitation other than that supplied by the flowing stream of oil until said reaction zone islargely filled with spent aluminum chloride and coke, introducing cool oil into the reaction chamber and circulating such cool oil through said chamber until the temperature of the contents thereof has fallen below 212 F., then introducing a dilute alkaline ysolution into the chamber and gradually displacing all` of the oil thereby, and finally flushing the said alkali and the spent aluminum chloride and coke from the chamber.

21. In the manufacture of low boiling distillates from higher boiling hydrocarbon oils, the' process which comprises heating said higher boiling oils in a iiowing stream to temperatures slightly below those required for thermal 4cracking, adding somewhat vr'above one per cent of aluminum chloride to 'the heated oils, feeding the mixture into a reaction zone maintained below thermal cracking temperatures, and at pressures suicient to prevent sublimation of the aluminum chloride and to maintain the bulk of the unconverted oilin liquid phase, and there continuously and substantiallyventirely converting saidj mixture-into distillate, coke and permanent gas, and withdrawing nothing but dis-` tillate and permanent gas from the lreaction zone until a Vsubstantial quantityof coke has accumulatedtherein. L

'f 22. In'the conversion of high boiling petroleum oils into lower boiling petroleum oils, 'the process which comprises continuously heating said higher boiling oils under substantial pressure to a temperature slightly below that required forf thermal cracking, discharging the oill into an unheated reaction zone maintained under .sub-1 stantial.l pressure, continuously adding aluminum chloride to the heated oil in such quantity the heavier oils to lower boiling .distillate and coke and gas and simultaneously'eiectma'ximum exhaustion ofthe aluminumchloride, and not removing spent aluminum chloride duringl the oil until said reaction zone is xlargely :filledfwith conversion step, continuing said .oil conversion the chamber and graduallydisplacing all of the oil thereby, and nallyflushing the'said alkali and the spent aluminum chloride yand coke from the chamber.

23. In Athe conversion of high boiling petroi leum oils into lower boiling petroleumr oils, the

process `which comprises continuously heating- `said higher boiling oils under high 'pressures to temperatures' slightly below those required for vthermal cracking, discharging the oils into an unheated reaction zone maintained under high pressures, continuously adding aluminum Chlo-i2()I l ride to the heated oilsin such' quantity as will eiect substantiallycomplete conversion ofthe heavier oils to lower boiling distillate, coke and gasesU and will simultaneously effect maximum' exhaustion of the aluminum chloride, and not y v'1.2 koil conversion step, continuing said oil couver-"14 removing' spent alurninl'lm` chloride duringl the sion without agitation other` than that suppliedf f by the flowing stream of oil 'until said reaction" zone is largely lled with spent aluminum chloride and coke, introducing cool oil into the reaction chamber and circulating such cool' oil throughisaid chamber until the temperature of the contents thereof has' fallen'below1212 F'., displacing the cooling oil by means of 'an aqueous liquid, thereby decomposing the spent aluminum chloride coke, 'and finally 'flushing the coke from the chamber.

24. In the conversionof high boiling petroleum oils into lower boiling petroleum oils,'the process which comprises continuously heating said higher boiling oils under substantial pressure' to a temperature slightly below that required Spent for thermal cracking, discharging the oil into an` unheated reaction zone maintained under substantial pressure, continuously adding aluminum chloride to the heatedoil in such quantity as will effect substantially total conversion of the heavier oils to lower boiling distillate and coke and gas and will simultaneously effect maximum exhaustion of the aluminum chloride, and not eejfif as win 'einen substantially total' conversion 0h95;y

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the contents thereof has fallen beow 212 F., dispacing the cooling oil by means of an come ous liquid, thereby decomposing the spent alumin num chloride coke, and nally ushing the spent coke from the chamber.

' iso

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