US1966639A - Hydrocarbon oil conversion - Google Patents

Description

um? 17 3934 J. c. MoRRl-:LL

HYDROCARBON OIL CONVERSION Filed Aug- 4 1928 Patented July 17, 1934 PATENT OFFICE HYDROCARBON OIL CONVERSION `lacque C. Morrell, Chicago, Ill., assignor to Universal Oil Products Company, Chicago, Ill., a corporation of South Dakota Application August 4, 1928, Serial No. 297,435

14 Claims.

The present invention relates to improvements in hydrocarbon oil conversion, and refers more' particularly to a processA and apparatus particularly designed to take a crude oil or other heavy charging stock, subject it to liquid phase conditions of conversion under heat and superatmospheric pressure, separate the vaporous from the nonvaporous products of conversion, dephlegmate the vaporous products of conversion and remove therefrom the gasoline-like constituents suitable for use as motor fuel, reduce or release altogether the pressure maintained on the nonvaporous residue, permitting same to flash due to the latent' heat contained therein, which is effective upon the reduction in pressure, combine certain fractions of the reflux condensate from the liquid phase cracking operation with 'the vapors released in the flashing operation and subject same to vapor phase cracking conditions.

The improvements of the present invention comprise returning to the ashing zone regulated portions of the highly heated vapors subsequent to having been subjected to vapor phase cracking for the purpose of imparting heat during the flashing operation to secure maximum vaporization. Other incidental advantages of an operation of this character include the removal of heavy taror pitch-forming ends normally entrained in said vapors which will be separated and deposited in the flashing zone.

As a feature of the present invention, the reduction in pressure of the non-vaporous residue subjected to ashing may be controlled to such an extent as to produce comparatively clean vapors to be combined with selected fractions of the reflux condensate for vapor phase cracking. The non-vaporous fractions of the residue remaining from that flashing operation may then be subjected t0 a further flashing operation brought about by a further reduction in pressure and regulated portions of the cracked vaporsv returned to either or both of the ashing zones for the purposes above described.

.The utility of the invention as 'well as other objects and' advantages thereof will be more apparent from the following description.

The single gure in the drawing is a diagrammatic side elevational view, partly in vertical section, of apparatus in which the invention may be carried out.

Referring more in detail to the drawing, 1 designates a charging line receiving charging stock from any suitable source of supplyandv pumping same by means of the pump 2 into the line 3, controlled by valve 4, which merges with charging stock @through the coil 10 in the 69 dephlegmator 11 'as is well known in conventional liquid phase cracking processes. Thecoil 10 communicates by means of the return line 8', controlled by valve 9', with the line 5.

The oil passing through the heating tube 6 '05 may be raised in temperature as desired, for instance from '800 to 950 F. and passed through transfer line 11', controlled by valve 12, into an enlarged drum 13 which may comprise a separating and/or conversion chamber. The chamber l13 is a standard part of conventional tube and drum liquid phase or liquid vapor phase cracking apparatus. It may be externally lagged to decrease loss of heat by radiation and may be preferably externally unheated. It is provided with the usual clean out openings 14. Vapors separating in the chamber 13 may pass out through the line 15, controlled by valve 16, discharging intoy the lower end of the dephlegmator 11 wherein in their ascent through the-dephlegmator they are subjected to the action of asuitable cooling medium, the temperature of which is so controlled as to condense the insufficiently converted fractions while permitting the sufficiently converted fractions to 3 pass out through the line 17,"controlled by valve 18, discharging into a second fractionating tower 19. The temperature conditions within the secondary fractionating tower 19 may be so controlled as to permit only those vapors having a boiling point range within the commercial specifications for gasoline to leave the top thereof through the outlet 20, being condensed to a liquid in condenser coil 21 mounted in condenser box 2,2 and being collected `as a nquid distiua 95,

in receiver 23, which may be provided with the gas draw-off line 24, controlled by valve 25, and the liquid draw-off line 26, controlled by valve 27.

Reux condensate collecting in the dephlegmator 11 may be removed through the line 28 and 100 the line 28 may be diverted through the line 105 31 by proper manipulation of the valve 32discharging into the still 33.

The reux condensate collecting in the secondary fractionating tower 19 may be removed through line 34 by proper manipulation of valve 110 35 or all or a regulated portion thereof may be diverted to still 33 through the line 36, controlled by valve 37. Where the pressure conditions are such that the pressure in dephlegmator 19 is lower than the pressure in chamber 33, the valve 37 may be closed and the valves 38 in by-pass line 39 opened to permit the pump 40 to operate to impose the necessary pressure on the liquid passing through line 39.

The heating tube 6 and drum 13 are preferably maintained under superatmospheric pressure from 125 to 300 lbs., more or less, depending upon the type of operation. The non-vaporous residue from drum 13 may be withdrawn through any of the branches 41, controlled by valve 42, into the header 43, from which latter said residue passes into the line 44, controlled by valve 45, said line 44 discharging into the still 33. By proper manipulation of the valves 42 and 45 the pressure previously maintained on said residue is reduced or released altogether, thus causing vaporization to take place in said chamber 33 due to latent heat contained in said residue and made effective upon such reduction in pressure.

Vapors released from the chamber 33 may pass out through the line 46 into the vapor phase heating coil 47 disposed in the furnace 48. From the coil 47 the heated vapors may pass through the line 49, controlled by valve 50, into a fractionating tower 5l. Or, all or regulated portions thereof may be diverted from line 49 and passed through line 52, controlled by valve 53, into still 54. Or, all or regulated portions of said highly heated vapors may be diverted from the line 52 into the line 55, controlled by valve 56, discharging into the still 33. The considerations for determining the return of said highly heated vapors will be hereinafter more particularly described.

The chambers 33 and 54 are connected in series by means of the branches 57, controlled by valves 58. Vapors released from still 54 are removed through the line 59 and may be passed into the fractionating tower 51. In the ascent of said vapors through the tower 5l they may be subjected to the action of a suitable cooling medium introduced thereto through the line 60, controlled by valve 6l. Vapors remaining uncondensed after passage through the tower 51 pass out through the line 62, being condensed in the coil 63 mounted in condenser box 64 and collected in the receiver 65, which is' of conventional type and which may be provided with the draw-01T 66, controlled by valve 67. Each of the stills 33 and 54 may be provided with the drain or discharge 68, controlled by valve 69. In addition, the still 54 may be provided with the draw-off 70 communicating with cooler 71 mounted in box 72.

As heretofore described in the introductory part of this description, the liquid phase operation may be so controlled as to produce three products, a non-vaporous product, which is removed from the drum 13 through the lines 41, a gasoline-like product, which is removed from fractionating tower 19 through line 20, and reflux, which is removed from fractionating tower 19 through line 36. By properly controlling the relative temperature conditions between towers 11 and 19 the liquid passing through the line 36 may be a product intermediate between the gasoline-like product removed through line 20 and the reflux condensate removed through line 28 and returned to heating tube 6 for further treatment. In any event, the heating tube 6 and drum 13 are maintained under superatmospheric pressure. The towers l1 and 19 may also, if desired,. be maintained under superatmospheric pressure.

'Ihe residue from drum 13 as well as the condensate from towers 11 or 19, or both, may dis- `charge into the first flash chamber 33 wherein vaporization takes place due to latent heat as heretofore described. Conditions in the chamber 33 may be maintained so as to produce in effect a clean vapor for passage through the vapor phase cracking tube 47 in order to avoid excess coke formation therein. The unvaporized residue from chamber 33 may pass through branches 57 into chamber 54 and by proper manipulation of valve 58 pressure may be released altogether, permitting further vaporization.

The primary purpose of returning to either or both of the flash chambers 33 and 54 regulated portions of highly heated vapors from tube 47 which have been subjected to vapor phase cracking is to impart heat during the flashing operation to secure maximum vaporization. In addition, where such vapors are returned to either of the chambers 33 or 54, or both, and more particularly when they are returned to chamber 54, heavy tar or pitch forming ends normally entrained in said vapors will be separated and deposited in said chambers.

One of the advantages of introducing regulated portions of said heated vapors to charnber 33 is to permit partial separation of vapors in chamber 33, the vcharacteristics of which are controlled by controlling the pressure on chamber 33. The purpose of this, as heretofore described, is to obtain relatively clean vapors for passage through the vapor phase heating coil 47 to avoid excess carbon formation in the heating coil. Flashing is then completed in chamber 54, which is at a substantially lower pressure than chamber 33 and can be carried down to 'the limits of flashing corresponding to the high temperature. resulting from the introduction of vapors from the vapor phase cracking coil 47. 'Ihese vapors leave the vapor phase cracking coil at approximately 1000 to 1100 F., and the characteristics of the residue from chamber 54 will depend upon whether all or part of the vapors from the vapor phase cracking coil 47 are passed into said chamber 54. residue withdrawn from chamber 54 may be a heavy pitch-like liquid, depending upon the amount and temperature of the vapors returned thereto. Reux condensate from the tower 51 may be returned to coil 6 through the line 73, in which may be interposed a pump 74 and valve 75, said line 73 merging with the line 5.

As an example of temperature and pressure conditions throughout the system, which is tol be taken as an illustration only and not in any sense as a limitation, the oil passing through transfer line 1l may be at a temperature of, say 800 to 950 F'. The pressure up to and in'- cluding dephlegmator 11 may be usual operating pressures, say 125 to 300 lbs., more or less. The pressure in the chamber 33 may be controlled to vary from 20 to 50 lbs., more or less. The temperature of the vapors leaving the vapor phase cracking coil 47 will vary between 950 and 1200u F., more or less. The pressure in chamber 54 will be substantially atmospheric, with suflicient pressure to overcome friction and force the vapors through column 51 and con- The final denser 63. The pressure in tower 19 may vary pressure evolved vapors from unvaporized oil and subjectfrom between 10 and 50 pounds.

The proper conditions of temperature and pressure will, of course, depend entirely upon the types of products desired and the characteristics of the charging stock. The process and apparatus are exceedingly iexible and are designed to meet all conditions.

Y I claim as my invention:

1. Hydrocarbon oil conversion, which comprises subjecting hydrocarbon oil to cracking conditions of temperature and superatmospheric pressure to cause vaporization, separating evolved vapors from unvaporized oil and subjecting said vapors to dephlegmation thereby separating by condensation insuiciently converted vapors, nally condensing the dephlegmated vapors reducing the pressure on the unvaporized oil in a ashing zone to cause vaporization by latent heat, subjecting resultant vapors to vapor phase cracking conditions and returning regulated portions thereof to said flashing zone, condensing the remaining portion of the vapor phase cracked vapors.

2. Hydrocarbon oil conversion, which comprises subjecting hydrocarbon oil to cracking conditions of temperature and superatmospheric to cause vaporzation, separating ing said vapors to dephlegmation thereby separating by condensation insuiciently converted vapors, finally condensing the dephlegmated vapors reducing the pressure on the unvaporized oil in a flashing zone to cause vaporization by latent heat, subjecting resultant vapors to vapor vphase cracking conditions and returning regulated portions thereof to said dashing zone, introducing to said flashing zone regulated portions of the condensed insuiciently converted vapors, condensing the remaining portion of the vapor phase cracked vapors.

3. A process such as claimed in claim 1, characterized in that the ashing operation is carried out in two stages by successive pressure reductions, and further characterized in that regulated portions of the vapors resulting from the vapor phase cracking are introduced to the second stage of pressure reduction.

1l. An oil cracking process which comprises subjecting the oil to cracking conditions of temperature and superatmospheric pressure, separating evolved vapors from unvaporized oil and condensing such separated vapors, lowering the pressure on the unvaporized oil in a zone of pressure reduction thereby effecting partial vaporization thereof, passing remaining unvaporized o'l to a second zone of pressure reduction and subjecting the same therein to further lowering in pressure to eect additional vaporization thereof, removing vapors from the first mentioned zone of pressure reduction and cracking the same in the vapor phase, subsequently introducing resultant cracked vapors into contact with the unvaporized oil in said second zone to assist vaporization therein, and removing vapors from said second zone subjecting them to condensation.

5. A process as defined in claim 4 further characterized in that said evolved vapors separated from said unvaporzed oil are dephlegmated to produce reflux condensate, at least a portion of the latter introduced tothe rst mentioned zone of pressure reduction for vaporization therein, and the resultant vapors thereof passed to said vapor phase cracking.

6. An oil cracking process which comprises subjecting the oil to cracking conditions of temperature and superatmospheric pressure, separating evolved vapors from unvaporized oil and condensing such separated vapors, lowering the pressure on the unvaporized oil in a zone of pressure reduction thereby effecting partial vaporization thereof, passing remaining unvaporized oil to a second zone of pressure reduction and subjecting the same therein to further lowering in pressure to effect additional vaporization thereof, removing vapors from the flrst mentioned zone of pressure reduction and cracking the same :fn the vapor phase, introducing resultant cracked vapors into the first mentioned zone of pressure reduction and into said second zone' of pressure reduction, removing 'vapors from said second zone and subjecting the same to condensation.

'7. An oil cracking process which comprises subjecting the 0'1 to cracking conditions of temperature and superatmospheric pressure, separating evolved vapors from unvaporized oil and condensing such separated vapors, lowering the pressure on the unvaporized oil in a zone of pressure reduction thereby effecting partial vaporization thereof, passing remaining unvaporlzed oil to a second zone of pressure reduction and subjecting the same therein to further lowering in pressure to effect additional vaporization thereof, removing vapors from the rst mentioned zone of pressure reduction and cracking the same in the vapor phase introducing separate portions of the resultant vapor phase cracked vapors into sad zones of pressure reduction, removing vapors from said second zone and subjecting the same to dephlegmation and nal condensation, and returning reflux condensate formed by said dephlegmation to said oil being subjected to crack'ng conditions of temperature and superatmospheric pressure.

8. An oil cracking process which comprises subjecting the oil to cracking conditions of temperature and superatmospheric pressure in `a heating zone, separating evolved vapors from unvaporized o'l, subjecting the evolved vapors to primary and secondary dephlegmation to produce a primary rei-lux condensate and a secondary refiux condensate, returning at least a portion of said primary reiiux condensate to said heating zone for retreatment in the process, passing said unvaporized oil to a zone of pressure reduction and reducing the pressure on the unvaporized ol therein to effect vaporization, passing said secondary reiiux condensate to said zone of pressure reduction and vaporizing the same therein, removing vapors evolved in said zone of pressure reduction and subjecting the same to vapor phase cracking, and subjecting the vapors uncondensed by said secondary dephlegmation and cracked vapors resulting from the vapor phase crack'ng to condensation.

9. A process as defined in claim 8 further characterized in that a portion of the cracked vapors from the vapor phase cracking is introduced to said zone of pressure reduction.

l0. A cracking process which comprises passing hydrocarbon oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under sufiicient superatmospheric pressure to maintain a substantial portion thereof in liquid phase, discharging the heated oil into an enlarged reaction zone maintained at cracking temperature and separating the same therein under superatmospheric pressure into vapors and unvaporized oil, separately removing the vapors and unvaporized oil from the reaction zone, subjecting the vapors to dephlegmation to condense and separate heavier insufficiently cracked fractions thereof and returning resultant reiiux condensate to the heating zone for retreatment therein, subjecting the vapors and gases uncondensed by the dephlegmation to further cooling and condensation and separating therefrom a condensate of lower boiling point than said reflux condensate, lowering the pressure on the withdrawn unvaporized oil while still hot and iiash distilling the same in a flashing zone maintained under lower pressure than the reaction zone, simultaneously vaporizing condensate formed by said further cooling and condensation and subjecting resultant vapors to vapor phase conversion in a second heating zone, discharging such heated vapors from said second heating zone directly into said fiashing zone and into contact with the unvaporized oil therein to assist the vaporization of the latter, removing the heated vapors from the fiashing zone and subsequently subjecting the same to dephlegmation and final condensation, and recovering resultant final condensate as a product of the process.

11. A cracking process which comprises passing hydrocarbon oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under sufficient superatmospheric pressure to maintain a substantial portion thereof in liquid phase, discharging the heated oil into an enlarged reaction zone maintained at cracking temperature and separating the same therein under superatmospheric pressure into vapors and unvaporized oil, separately removing the vapors and unvaporized oil from the reaction zone, subjecting the vapors to dephlegmation to condense and separate heavier insuiiiciently cracked fractions thereof and returning resultant refiux condensate to the heating zone for retreatment therein, further fractionating the gasoline-containing distillate uncondensed by said dephlegmation and separating the same into a light gasoline condensate and a liquid fraction of boiling range intermediate said reflux condensate and said light gasoline condensate, lowering the pressure on the Withdrawn unvaporized oil while still hot and flash distilling the same in a flashing zone maintained under lower pressure than the reaction zone, simultaneously subjecting said intermediate liquid fraction to vaporization and heating the resultant vapors to conversion temperature in a second heating zone, discharging such heated vapors from said second heating zone directly into said flashing zone and into contact with the unvaporized oil therein to assist the vaporization of the latter, removing the heated vapors from the fiashing zone and subsequently subjecting the same to dephlegmation and final condensation, and recovering resultant final condensate as a product of the process.

l2. A cracking process which comprises passing hydrocarbon oil ina restricted stream through a heating zone and heating the same therein to cracking temperature under sufficient superatmospheric pressure to maintain a substantial portion thereof in liquid phase, discharging the heated oil into lan enlarged reaction zone maintained at cracking temperature and separating the same therein under superatmospheric pressure into vapors and unvaporized oil, separately removing the vapors and unvaporized oil from the reaction zone, subjecting the vapors to'dephlegmation to condense and separate heavier insufliciently cracked fractions thereof and returning resultant reflux condensate to the heating zone for retreatment therein, subjeeting` the thus dephlegmated vapors to secondary dephlegmation to form an overhead vapor of motor fuel boiling range and a light secondary reflux condensate, finally condensing said overhead vapor, lowering the pressure on the withdrawn unvaporized oil while still hot and iiash distilling the same in a flashing zone maintained under lower pressure than the reaction zone, simultaneously subjecting said secondary reflux condensate to vaporization and heating the resultant vapors to conversion temperature in a second heating zone, discharging such heated vapors from sald second heating zone directly into said ashing Zone and into Contact with the unvaporized oil therein to assist the vaporization of the latter, removing the heated vapors from the fiashing zone and subsequently subjectingthe same to dephlegmation and final condensation, and recovering resultant final condensate as a product of the process.

13. A cracking process which comprises passing hydrocarbon oil in a restricted stream through a heating zone .and heating the same therein to cracking temperature under suiilcient superatmospheric pressure to maintain a substantial portion thereof in liquid phase, discharging the heated oil into an enlarged reaction zone maintained at cracking temperature and separating the same therein under superatmospheric pressure into vapors and unvaporized oil, separately removing the vapors and unvaporized oil from the reaction zone, subjecting the vapors to dephlegmation in primary and secondary dephlegmating zones maintained under substantial superatmospheric pressure, finally condensing the thus dephlegmated vapors, returning refiux condensate from the primary dephlegmating zone to the heating zone' for retreatment therein, lowering the pressure on said unvaporized oil while still hot and ash distilling the same in a fiashing zone by the pressure reduction, simultaneously removing secondary reflux condensate under superatmospheric pressure from said secondary dephlegmating zone and lowering the pressure thereon thereby effecting substantial vaporization thereof, heating the resultant vapors to vapor phase conversion temperature in a second heating zone, discharging such heated vapors from said second heating zone directly into said fiashing zone and into contact with the unvaporized oil therein to assist the vaporization of the latter, removing the heated vapors from the flashing zone and subsequently subjecting the same to dephlegmation and final condensation, and recovering resultant final condensate as a product of the process.

14. The process as defined by claim 13 further characterized in that the flashing zone is maintained under lower pressure than the secondary dephlegmating zone and in that the secondary reflux condensate withdrawn from the latter is introduced to the former'for vaporization therem.

JACQUE C. M ORRELL.

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