US2210901A - Process for cracking hydrocarbon oils - Google Patents

Description

Aug. 13, 1940. B. P. cRlTTI-:NDEN

PROCESS FOR CRACKING HYDROCARBON OILS original Filed April 4, 1932 m mm n TT IN R MC n E, A R mm Patented Aug. 13, 1940 UNITED STAT'.

PATENT yorties I PRGCESS FOR RACKING HYDROCARBON OILS Butler P. Crittenden, Shreveport, La., assigner, by mesne assignments, to Arkansas Fuel Oil Company, a corporation of yWest Virginia Original application April 4, 1932, `Serial No.

Divided and this application February 6, 1937, Serial No. 124,392

3 claims. (el. 19e- 48) lation of coal andwood, as Well as the distillates and residues of such products. By this inven- 'lo tion heat is applied to the oils or hydrocarbons 4in such a manner that anti-detonating motor fuels are produced together with other products which may be converted in large part into antidetonating motor fuels. At the same time gases I5 and other liquid products, as Well as so-lid residues are produced.

This application is a division of application Serial No.` 602,969, filed April 4th, 1932 for Process for treating hydrocarbon oils which -in turn :20 is a continuation in part of the applicants earlier application Serial No. 491,101, led- October 25th, 1930 for Combined liquid phase and vapor phase oil cracking process. The application Serial No. 491,101, discloses a combined cracking process in -25 which vapors from the cracking operation separated outY in an enlarged separating vZone are passed through a plurality of fractionating zones in which a series of fractional condensates are formed-of higher boiling po-int than the desired .30 lgasoline product. A portion of the very heavy condensate is returned to the separating zone While other reflux condensates are separately cracked in cracking coilsV Which discharge into the enlarged separating chamber. The lighter -35 condensate is subjected to a higher temperature than the heavier condensate. Preheated heavy oil is mixed With the transfer products from ,one of the coils and discharged into the enlarged separating zone in contact with the vapors and f4() liquids therein.

Anal-rangement of apparatus is somewhat diagrammatically shown in the accompanying drawing by which the invention may be carried out.

-f45 In the drawing Vreference character I indicates a storage tank for crude or reduced petroleum oils, for example. kA pipe line 2 in which a pumpr 3 is located leads. from the tank I through heat exchangersl. 5 and 6 to the tubular heating 60 elements or coil 1 located in the furnacey 8. .i

Valved bypasses 9, I and II maybe provided in the pipe line 2 around the heat exchangers 4, 5 and 6 so that any desired portion of the material from the tank I maybe passed to the heat- `155 ying coil 1 Without passing through the heat eX- changers 4, and 6. v A pipe line I2 leads from f the coil 1 to a receiver I3.

An outlet I4 for the heavy residues from the receiver I3 leads to an evaporator I5. An outlet i6 for coke or heavy residue is provided at the `5 bottom of the evaporator I5.

A vapor outlet I1 extends from the upper por- .tion of the evaporator I5 to the partial condenser 18. A-.condensate outlet pipe I6 leads V from the lower portion of the condenser YI8 10 through the cooler to the reservoir 2l. `A pump 22 is provided in the outlet 23` from the reservoirv 2|. The loutlet 23 is divided into Valved branches, one of which may lead to a storage tank and the other to the pipe 24 which Al5 leads back tothe receiver I3. Y

A vapor outlet pipe 25 leads from the receiver I3 to the first one of a series of heat exchangers of direct or indirect contact type. Four of these lexchangers 261|, 262, 263,'and 264 are illustrated, 20 although this number may be varied. The pipe 25 leads from the last heat exchanger of the series toa fractionating column 21 of the Wellknown sort. Valved outlet 'pipes 281, 282, 283 and 284 lead from the heat exchangers 261, 262, 25 26a, and 264 to the `pipe 28 which is provided with valves so that the material entering it can be passed to the receiver I3 or the evaporator I5 or the fractionating column 21,'or selected portions may be diverted respectively to Whichever 30 of these receptacles as` is desired.

An outlet-pipe 23 for the heavy fraction from the fractionating column 21 is provided with a vpump 3D and leads to the heating device or coil 3l through heat exchangers such as 264 and 261, 35

forexample.. An outlet pipe 32 leads from the coil 3l to the pipe I2. v

A vapo-r pipe 33 extends from the fractionating columnl 21 tothe heat exchanger 5' and thence to a fractionatingcolumn 34 similar to the rst v40 one. A vapor pipe 35 extends from the fractionating column 34 to the heat exchanger 4 and thence to the condenser' 36.

` An outlet pipe 31 for condensates from the co1 umn 34 .leads to areservoir 38 from Which an 45 outletpipe 38 provided With a pump 39 leads to a pipe40 which leads to the heating element or vcoil 4I-in the furnace42.v

A storage tank 43 is provided which may contain gas oil. A` pipe 44 providedwith a pump 45 5"0 isalso provided with branches 46, 41, 48 and `49 `leading respectively to the fractionating column 34, fractionating column 21, pipe 2, and pipe I2.l .A storage tank 50 is provided which may contain kerosene or heavy naphtha. A pipe 5| pro- 55 vided with pumps 52 and 52 leads from the tank 50 and also from line 38 and receiver 38 through the heat exchangers 263 and 262, with a valved bypass 5I around them, to tubular heating elements or coil 54 in the furnace 42. 'Ihe outlet 55 from the coil 54 leads to the pipe I2. A valved branch line 53 leads from the pipe 5I and pump 52 to the reservoir 38 so that all or a portion of the material from tank 5I] or pipe line 24 may be passed either through line 5I or line 53.

A pipe 51 from any convenient source of superheated steam extends into the evaporator I5. The steam may be superheated to a temperature of about 1000 F. The pipe lines 40 and 55 are connected by valved connections to the steam pipe 51.

A valved branch pipe 53 extends from the outlet pipe I4 from the receiver I3 to a cooler 58. An outlet pipe 60 provided with a pump 6I extends from the cooler 59 to a storage tank (not shown) and a valved branch pipe 62 is connected from the pipe 60 to the pipe I4 near the evaporator I5. A valved pipe 63 extends from the lower portion of the evaporator I5to the pipe 60.

A vapor outlet pipe 64 extends from the partial condenser I8 to a secondary condenser 65 from which a condensate outlet pipe 66 leads to a reservoir 61. An outlet pipe 68 provided with a pump 10 leads away from this reservoir 61'. The outlet 1I of the pump is divided into valved branches one of which leads to a storage tank (not shown) and the other one to the pipe 24. An outlet pipe 12 for uncondensed gases leads from the condenser 65 to a pressure pump 'I3 and thence to a gas storage tank (not shown).

An uncondensed gas pipe 14 also leads from the condenser 36 to the pipe 12. An outlet pipe 15 for condensates leads from the condenser 36 to the cooler 16 from which a pipe 11 leads to the reservoir 18. An outlet pipe 19 provided with a pump leads away from the reservoir 18. A gas pipe 8I leadsfrom the reservoir 18 to the pipe 12. A pipe 82 provided with a pump 83 leads from the pipe 15 to the fractionating column 34.

A pipe line 84 provided with a pump 85 passes hot fuel oil from the receiver I3 through heat exchanger 6 thence to pipe I4. Pipes 81 and 86 return condensates from heat exchangers 5 and 4 to fractionating columns 21 and 34 respective- Valves are indicated in the Various pipes at appropriate locations by crosses so that the apparatus can be manipulated in accordance with the desired conditions of operation.

The following are given as speciiic examples of carrying out the invention with the arrangement of apparatus shown on the drawing, but it is to be understood that the invention is not restricted to these particular examples:

Reduced crude oil such as the fraction having an initial boiling point of about 300 F. and an end boiling point of about 850 F. from which light fractions have been distilled oif is supplied to the tank I from which it is passed through the pipe 2 by the pump 3 through the heat ex changers 4, 5 and 6 to the heating coil 1 which it reaches at a temperature of about 700 F. It passes through the coil I in about 4 to 5 minutes and leaves this coil at a temperature of about 850 F. and passes to the receiver I3 through a common pipe I2, together with material from `coil 4I or 54, or both.

passing out through pipe 25 and a liquid portion passing out through pipe 84 and pump 85, through heat exchanger 6 into line I4. The vapors passing out through the pipe 25 are partially condensed in the heat exchangers 261, 262, 263 and 264 from which the condensates are Withdrawn to the pipe 28. The remaining vapors pass to the fractionating column 21. The condensed residues from the column 21 having an initial boiling point of 350 F. and a final boiling point of 750 F. are passed through one or more of the heat exchangers 261 to 264 and line 29 to the coil 3I which they reach at a temperature of about 700 F. They pass through this coil in about 12 to 14 minutes and lleave it at a temperature of about 860 F. to 910 F. and thence to the receiver I3.

The vapors leaving the fractionating column 21 pass through the heat exchanger 5 and thence to the fractionating column 34. The condensate from the column 34 having an initial boiling point of about 350 F. and a iinal boiling point of about 700 F. passes into the receiver 38 and. thence through pump 52', the line 5| and heat exchangers 263 and 262 to the coil 54 which it reaches at a temperature of about 700 F. taking about 15 to 20 minutes to pass through, leaving this coil at a temperature of about 920 F. to 980 F., from which it passes to the receiver I3; or, a fraction or all of it may be diverted to the line 51 and thence `to the evaporator I5.

Als-o, part of the material from the receiver 38 may be passed through pump 39 into line 4I) along with some iixed gases from the process to the heating coil 4I, which they reach at a temperature of about 400 F. taking about 30 minutes to pass through this coil. They leave this coil at about a temperature of 975 F. to 1150 F. and pass through the pipes 55 and I2 into the receiver I3, or the elilux from the coil 4I or a portion thereof may be diverted through line 51 to the evaporator I5.

The vapors leaving the fractionating column 34 pass through the heat exchanger 4 to the condenser 36. The uncondensed gases pass from the condenser 36 through the pipe 14 to the pipe .r

12 and pressure pump 13 and thence to line 40 or a gas storage tank (not shown). Condensates having an initial boiling point of F. and an end point of 450 F. pass through the outlet 15 to the cooler 16 and thence to the receiver 18 from which they pass to a storage tank (not shown) through the pipe 19. Uncondensed gases from receiver 18 pass through the pipe 8lr to the pipe 12. A portion of the condensates leaving the condenser 36 may be passed by means of the pump 83 back into the fractionating column 34.

The condensates from the heat exchangers 261, 262, 263 and 264, vary in their gravities and boiling points, the heaviest ones being from the earlier heat exchangers in the series. runs the boiling point of the condensates passing out through the outlet 281 have been found to have an initial boiling pointof 440 F. and an end boiling point of 138 and a gravity ranging from 10 B. to 18 B.; those from 282 having 3 a boiling point ranging from 406 F. to 700 F. with specific gravity in range from 12 B. to 19 B.; those from 283 having a boiling range of 320 F. to 700 F. and a gravity range of 16 to 22 B.

and those from 284. having a boiling range from 230 F. to 700 F. with a gravity from 16 B. to 24 B.

By manipulation of the valves in the pipe 28 such a portion' of these condensates as is desired is returned to the receiver I3 and the remaining In actual portion is passed to the fractionating column 2l. rThe portions returned to the receiver I3 are in general the heavier portions and they servein this receiver I3 for at least two purposes. One is to absorbexcess heat that had been furnished by the furnaces 8 and 42, and the other is to per-'- mit of the conversion of these condensates into materials of a desired type through admixture with the high temperature vapors from the coils heated by the furnaces 8 and 42.

The portion of the con-densates from the heat exchangers which reach the pipe 28 and are passed to the column 27 are in general the lower boiling portions` resulting from two sources, namely the re-boiling of the condensates diverted to the receiver I3 and the light fractions from the vapors entering the receiver I3 through line l2. f

If condensates reaching the pipe 28 are found to be valueless or harmful for producing antidetonating fuels they can be diverted by manipulation of the valves to pass either to the evaporator I5 or out `of the system through the pipe 60.

With this system of apparatus, starting with reduced crude oil, the valves maybe manipulated when desired in such a manner that all or a portion of the condensates reaching the pipe 28 vcan be passe-d into theevaporator Iii. This may be desirable, for example, When it has been found by analyses of these condensates that so much of the hydrogen has been removed that it is inadvisable to return them to the receiver I3. When they are passed to the evaporator I5 they are therein cracked by the high temperature products received through the line 57'! and as a result coke or extraordinarily heavy residues are produced and can be Withdrawn through the outlet I While anti-detonating products and intermediate products suitable for the production of anti-detonating products are simultaneously produced and pass out through the pipe I1.

In carrying out this invention condensates leaving the condenser I8 have been found to have an initial boiling point of 288 F. and final boiling point of 800 F. and a gravity range of about 8 B. to about 18 B. The condensates from the condenser 65 had an initial boiling point of 150 F. and final boiling point of 640 F. with gravity range from about 30 B. to about 50 B.

When treating reduced crude as described above it is sometimes found desirable to introduce some gas oil from the tank 43. This may be done by passing some gas oil having an initial boiling point of 350 F. and a nal boiling point of 750 F. through the pipes 45, 4l and 49 to the fractionating columns 34 and 2l" and to the receiver I3 through the transfer line I2. The products from this gas oil thereby become distributed in the system, thus making it more flexible in operation.

Also, it may be advantageous to introduce into the system kerosene or heavy naphtha, or condensates from the condensers IS and 65. The kerosene or heavy naphthas may have been obtained from crude oil which was the source of the reduced crude in the tank I. In such cases the kerosene, etc. is introduced into the system either through the line 53 and receiver 3S, or through the line I and heating coil 54 in such a manner that the light boiling fractions contained therein and of known poor anti-detonating characteristics will be so reacted upon by temperatures Within the system that anti-detonating gasoil may be introduced through the pipes 45 and 4'! into the fractionating columns 34 and 21. The gas oil, or the portion thereof that is not introduced into the 'columns 34 and 2l may be 'passed through the pipes v40 'and I2 into the re-v ceiver I3. On the other hand, When its composition is such as to make it desirable to subject it to heat before passing into the receiver I3 it may `be passed through pipes 48 and 3 and the heating coil 'I and thence through the pipe I2 into the receiver I3. `Constituents in this gas oil which would make such heating desirable are heavy paraffin fractions or heavy tarry fractions which need to be heat treated before they enter the receiver I3'. l lThe operation from the receiver I3 is similar to that already described in that condensates 'frornthe-heat exchangers 261, 262, 263, and 254 may .be recirculated to the receiver I3 or pass to the column '21, or tothe evaporator I5, or out through the line 60, depending upon the same factors asr already explained.' In a similar way f reducedcru-des from 'the tank I and kerosene or heavy,n ap'ht'has from the tank 50 may be intron [duced .intofthe system when gasoil is being treated as 'just described, thus utilizing the reduced crude and/or kerosene for the production of additional anti-detonating compounds.

Whether reduced crude or gas oil is the main portion of the hydrocarbon that is` undergoing treatment by this process, fixed gases may be passed through the pipe40 and coil 4I into the receiver I3 or evaporator I5, and condensates from the condensers I8 and 65 may be returned through the pipes 24 and I2 to the receiver I3 or through the pipe 24 to receiver 33, or pipe line 5I, or tank 50.

It has been found in operating the process that the pressure in the coil 'I should be kept at about 150 to 400 pounds per square inch; that the pressure in coil 3| should be kept at about 400 to 700 pounds per square inch; that the pressure in the coil 4I should be kept at about 100 to 300 pounds and that the pressure vin the coil 54 should be kept at about '700 to 1000 pounds per square inch. The pressure in the receiver I3, fractionating columns 21 and 34 should be about 30 to 60 pounds per square inch; and the pressure in the evaporator I5 may range from about 25 inches of mercury to 60 pounds per square inch.

'The gas which passes through pipe 40 may be from the system or from the gas storage tank, or it may be natural gas or industrial hydrocarbon gases.

Having thus described the invention,r what is claimed as new is:

1. In the process of converting hydrocarbon oil to produce anti-detonating motor fuel in which a stream of such oil to be converted is subjected to conversion conditions;` of temperature and pressure in a heating and converting zone and the resulting heated products passed into a vapor liquid separating zone wherein vapors are separated from liquid products, the improvement Which comprises passing the separated vapors from said separating zone through a. series of at least three indirect heat exchange Zones and then through a plurality of fractionating zones in series where the vapors pass in contact with charging oil, passing the charging oil and reflux condensate from the first fractionating Zone through the last and first indirect heat exchange Zones of the series in heat exchange with vapors and then into said heating zone to be converted into antidetonating products, passing condensate formed in the first indirect heat exchange zone Without additional heating into said separating zone and converting a portion to anti-detonating motor fuel, independently passing a mixture of reflux condensate and charging stock from the second of said fractionating zones through an intermediate heat exchange zone of said series and independently heating the mixture to a higher temperature than that to which the oil is heated in said heating zone to convert the mixture into antidetonating products, and passing at least a portion of the resulting heated products into said separating zone.

2. The process of converting hydrocarbon oils to produce anti-detonating motor fuel, which comprises passing a high boiling residue-containing hydrocarbon oil in a confined stream of restricted cross-section through a heating zone and heating the oil therein to a temperature of approximately 850 F., passing the resulting heated oil constituents into an enlarged separating chamber in which vapors are separated from unvaporized residual oil constituents, passing vapors produced in the cracking operation from said enlarged chamber into a tower in contact with a heavy oil charging stock, passing uncondensed vapors from said tower into a fractionating tower in which constituents of higher point than the desired motor fuel products are condensed as reflux condensate, withdrawing unvaporized residual oil constituents from said enlarged chamber into an evapcrating chamber, passing vapors from said evaporating chamber and fractionating them to produce a condensate suitable for cracking, mixing said condensate with said reux condensate from said fractionating tower, passing the resulting mixture in a confined stream of restricted cross-section through a heating zone and heating the mixture therein to a high temperature and passing at least a portion of the resulting products while at said high temperature into contact with the unvaporized residual oil in said evaporating chamber, passing charging stock and high boiling condensate froml said rst-men tioned tower through a heating coil in which the mixture is heated to a cracking temperature, and

mixing the resulting products with the highly heated products of said first-mentioned heating Zone and thereafter introducing the resulting combined mixture into said enlarged chamber.

3. The process of converting hydrocarbon oils to produce anti-detonating motor fuel as defined by claim 2 in which a heavy condensate is produced from vapors evolved in said evaporating chamber and introducing said condensate into said resulting combined mixture passed into said enlarged separating chamber.

BUTLER P. CRITTENDEN.

CERTIFICATE OF CORRECTION.

Patent No. 2,210,901. August 15, 19L1o.

BUTLER P. CRITTENDEN.

It '1s hereby certified that error appears in the printed specification of the above numbered patent reqniring correction as follows: Page 2, second column, line 6b., for "1580 F." read --7580 F.; and that the'said Letters Patent should be read with this. correction therein thatv the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of October, A. "D. 19110.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

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