US1946463A - Process and apparatus for converting oils - Google Patents

Description

Feb. 6, 1934. c. P. DUBBS PROCESS AND APPARATUS FOR CONVERTING OILS O igi a1 Filed June 22, 1921 Cirbon Pflubb ma -(Mug,

Patented Feb. 6, 1934 PROCESS AND APPARATUS FOR CONVERTING OILS Carbon P. Dubbs, Wilmette, 111., assignor to Universal Oil Products Company, Chicago, 111., a corporation 01' South Dakota Application June 22, 1921, Serial No. 479,445 Renewed March 10, 1927 24 Claims. (01. 196-49) This invention relates to improvements" in process and apparatus for converting oil and refers more particularly to a process for treating oils in successive stages of distillation.

5 Among the salient objects of the invention are to provide a process in which hydrocarbon oils of a relatively high boiling point are distilled in succeeding stages of distillation, each stage being maintained at a reduced pressure to that immediately preceding it; to provide a process in which the distillate produced in each stage may be drawn off or rerun for retreatment through the stage in which it was produced and a process in which the reflux condensate from each succeeding stage may be returned and retreated in the higher pressure initial stage of distillation; to provide a process in which the temperatures at which the oil vapors in the respective stages are passed over to be condensed into distillate, are regulated by controlling the supply of cool raw oil which isintroduced to the dephlegmating stages; to provide a process in which a mixture of the reflux condensate and raw oil from each stage is raised to the pressure of the initial stage of distillation and introduced thereto for retreatment; to provide a process in which hydrocarbon oil may be converted to coke and oil distillate, there being removed during the conversion, distillates of relatively low boiling point and distillates adapted to be refined into marketable gasoline; to provide an apparatus for carrying out the above-described process.

The single figure in the drawing is a diagram matic side elevational view of the apparatus.

Referring in detail to the drawing, the apparatus is shown in three stages, although it is understood that any number of stages may be used for the conversion of the oil. The oil drawn from any convenient source flows through the raw oil pipe 1 and may be charged to the respective stages through the secondary charging lines 2, 3 and 4 controlled by valves 5, 6 and '7, respectively, these charging lines introducing the raw oil into the top of the dephlegmators 8, 9 and 10. The raw oil thus introduced serves as a refluxing medium flowing in an opposed direction to the oil vapors which rise in the dephlegmators and refiuxes out the higher boiling point fractions. Referring first to the initial stage, the raw oil introduced thereto with what condensate it may collect in the dephlegmator, is drawn off through the line 11 regulated by a valve 12 and passes to the heating tubes 13 through the line 14. The oil, after being heated to a cracking temperature in the heating tubes which are mounted in the furnace 15, passes ferred through the line 23 controlled by a valve 24 to a pump 25 where it may be charged back into the top of the dephlegmator 8 through the line 26 regulated by a va1ve'2'7. By thus returning the distillate, it is again subjected to the higher temperature of the vapors rising in the dephlegmator which serve to redistill the liquid oil distillate returned from the receiver. The liquid oilwhich is not vaporized in the chamber 16, passes through the line 28 regulated by a reducing valve 29 and flows into the chamber 30, where, due to the reduced pressure conditions, vapors are again released from the oil body. The vapors released in this chamber pass ofi through the vapor line 31 through the refluxing or dephlegmating tower 9 and are condensed in the water condenser 32 from which the distillate is collected in the receiver 33. In this stage similarly to the initial stage, the distillate may be drawn off through the valve 34 or may be returned through the line 35 controlled by a valve 36 and a pump 3'7 to the de phlegmator 9 through the line 38 in which is in-= terposed the valve 39.

By controlling the supply of oil introduced through the line 3, the temperature of the vapors which pass over from the top of the dephlegmator .9 may be accurately controlled. The reflux from this dephlegmating tower together with the raw oil which is introduced through the line 3 is drawn 011 from the bottom of the dephlegmator through the pipe 40 controlled by a valve 41, through which it is charged through the pump 41a into the line 14. This line is connected directly with the heating tubes when the valve 42 is open, and when it is closed, the reflux from the second stage is directed through the vertical line 43 controlled by a valve 44 and is introduced into the top of the dephlegmator 8 of the first stage in quantities regulated by the valve 44 in the line 43. In the same manner, the unvaporized oil from the second chamber 30 is passed through the line 45 controlled by a second reducing valve 46 and flows into the chamber 47 where the reduced pressure permits further vaporization. The vapors released in this stage pass ofi through the line 48 to a dephlegmator 10 into the condenser 49 and receiver 50. As before, the distillate collected therein may be drawn ofi through the valve 51 or returned through the line 52 and pump 53 to be charged into the top of the dephlegmator 10 through the line 54 controlled by a valve 55. Similarly, the mixture of reflux and raw oil is drawn ofi from the bottom of the dephlegmator or refluxing column through the line 56 regulated by a valve 57 and may be charged through the pump 58 through the line 59 in which is interposed the valve 60 into the line 14 where it proceeds directly to the heating tubes to be retreated or if the valve 42 is closed, to the top of the first stage dephlegmator through the line 43.

The chambers 30 and 47 are mounted on furnaces 61 and 62, and all of the chambers and pipes are heavily insulated so that desired heat conditions may bemaintained throughout the system at all times. The reduction of pressure betwen the succeeding stages will be governed wholly by the character of the oil used and the distillate which it is desired to obtain. Each of the receivers is equipped with pressure relief valves 63 and other appurtenances necessary for the regulation of operating conditions in the respective stages. Pyrometers may be mounted in the top of the dephlegmators and in the vaporizing chambers for controlling accurately the temperature of the oil. Pressure gauges 64 in the receivers serve to register at all times the pressure in the difierent stages. The oil' thus converted in succeeding stages of reduced pressure may be relieved of substantially all of its lower boiling point fractions and very completely cracked. The returning and redistilling of the distillate in the stage in which it is produced and further returning the reflux to the initial stage of redistillation under the higher temperature and pressure conditions produces a maximum degree of cracking and conversion of the oil treated. The mixing of the raw oil with the reflux in the separate stages promotes distillation therein and reduces materially the temperature and pressure conditions normally, necessary to distill these higher boiling point oils which pass over to the second and third stage of distillation. In the last stage, the distillation is practically completed and the final product remaining in the vapor chamber will be coke or a very heavy carbonaceous material.

By converting gas oil at 300 pounds pressure in the first stage, 150 pounds in the second stage and reducing the pressure to atmospheric in the third stage, it is possible to obtain from 40 to 50% of 48 to 50 degrees Baum gravity distillate in the first stage, and obtain 25% of 45 degrees Baum gravity distillate in the second stage, while in the third stage, a somewhat heavier distillate is obtained, and the oil vaporized to coke therein.

I claim as my invention:

1. A process of converting hydrocarbon oil, consisting in subjecting the oil to an initial conversion treatment by passing it through a unit comprising a heating coil, vaporizing means and a dephlegmator, in maintaining said initial unit under a superatmospheric pressure, in passing unvaporized oils while in ahighly heated condition from the vaporizing means of said initial unit successively through succeeding units, in reducing the pressure on the oil in each of said succeeding units to vaporize substantial portions or the oil under the reduced pressures, in dephlegmating, condensing and collecting the vapors evolved in each of the succeeding units, in returning the distillate produced in each unit to the dephlegmating zone or that unit for redistillation therein, in returning the reflux condensate produced in the several units to the heating coil of said initial unit for re-treatment.

2. A continuous process for treating hydrocarbon oils, consisting in subjecting the oil to a conversion treatment in an initial unit, comprising a heating coil, vaporizing means and a dephlegmator, in maintaining a superatmospheric pressure on the oil undergoing treatment in said initial unit, in continuously withdrawing unvaporized oil from said initial unit and in passing it to the succeeding units wherein the oil is maintained under successively lower pressures to cause a substantial vaporization thereof, in separately dephlegmating, condensing and collecting the vapors evolved in each of the succeeding units, in controlling the temperature of the dephlegmating zone of each unit by the introduction of raw oil and the pressure distillate produced in that unit thereto, and in passing the raw oil and reflux condensate from the dephlegmating zone of each unit to the inlet side of the heating coil of said initial unit.

3. A continuous process for treating hydrocarbon oils, consisting in subjecting the oil to conversion conditions in an initial unit, comprising a heating zone, a reacting zone and a dephlegmating zone, in continuously passing unvaporized oil from the reacting zone of said initial unit to and through succeeding units, each succeeding unit being maintained under successively lower pressures to vaporize a substantial portion of the oil therein, in separately dephlegmating, condensing and collecting the vapors evolved in each of said succeeding units, and in returning pressure distillate produced-in each of said succeeding units to the dephlegmating zone of that unit to act as a dephlegmating medium for the vapors therein.

4. In an apparatus for converting oil, the combination with a series of connected distillation units, comprising an initial unit having a heating coil, a reacting chamber, dephlegmating and condensing means, successive units each comprising a reacting zone, and dephlegmating and condensing means, of means for returning the distillate produced in each unit to the dephlegmating zone of that unit for re-distillation, means for passing the reflux condensate from the dephlegmating zone of each unit to the inlet side of the heating coil of said initial unit, and means for maintaining difierential pressures in the respective units.

5. A process for converting hydrocarbon oil, comprising passing the oil in a restricted stream through a heating coil disposed within a fur nace, wherein it is raised to a cracking temperature, delivering the heated oil, while at a cracking temperature, to an enlarged reaction chamber, maintaining a superatmospheric pressure on the oil in said coil and reaction chamber, removing vapors evolved from the oil in said reaction chamber, passing unvaporized oil from said reaction chamber to a secondary chamber, maintaining a lower pressure on the oil in said secondary chamber than is maintained in said reaction chamber, to effect vaporization of a substantial quantity of the unvaporized oil in said secondary chamber, removing vapors evolved from the oil in said secondary chamber, introducing said last mentioned vapors to a fractionating column, passing charging oil for the process first in intimate contact with vapors in the vapor space of said fractionating column, thereafter passing the charging oil in heat interchange relation with vapors removed from said reaction chamber, and subsequently admitting the charging oil to said heating coil.

6. A process for converting hydrocarbon oil, comprising passing the oil in a restricted stream through a heating coil disposed within a furnace, wherein it is raised to a cracking temperature, delivering the heated oil, while at a cracking temperature, to an enlarged reaction chamber, maintaining a superatmospheric pressure on the oil in said coil and reaction chamber, removing vapors evolved from the oil in said reaction chamber, passing unvaporized oil from said reaction chamber to a secondary chamber, maintaining a lower pressure on the oil in said secondary chamber than is maintained in said reaction chamber, to effect vaporization of a substantial quantity of the unvaporized oil in said secondary chamber, removing vapors evolved from the oil in said secondary chamber, introducing the same to a fractionating tower, passing charging oil for the process in physical contact with vapors removed from said secondary chamber in the vapor space of said tower and in physical contact with the vapors removed from said reaction chamber, and thereafter introducing the charging oil to the heating coil.

7. A process for converting hydrocarbon oil comprising passing the oil in a restricted stream through a heating coil disposed within a furnace, wherein it is raised to a cracking temperature, delivering the heated oil while at a cracking temperature to an enlarged reaction chamber, maintaining a super-atmospheric pressure on the oil in both said coil and reaction chamber, removing vapors first evolved from the oil from said reaction chamber, passing unvaporized oil from said reaction chamber to a secondary chamber, maintaining a lower pressure on the oil in said secondary chamber than is maintained in said reaction chamber suflicient to eifect vaporization of a substantial quantity of the unvaporized oil by its contained heat in said secondary chamber, removing vapors evolved from the oil in said secondary chamber, initially passing charging oil for the process in counter-current flow and in physical contact with the vapors last evolved from the oil, subsequently passing the charging oil together with such condensate as is separated from the vapors last evolved from the oil in counter-current flow and in physical contact with the vapors first evolved from the oil, and thereafter delivering the charging oil and condensate separated from the vapors to said heating coil.

8. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-contained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower, so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors to condensation, passing the vapors from the pressure still into a reflux tower and introducing admixed condensate and unvaporized fresh oil from the first mentioned tower into direct contact with the vapors therein, and returning reflux together with admixed unvaporized oil from the said reflux tower to the pressure distillation.

9. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-contained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors to condensation, passing the vapors from the pressure still into a reflux tower and introducing admixed condensate and unvaporized fresh oil from the first mentioned tower while still in a heated state therefrom into direct contact with the vapors in the said reflux tower, and returning reflux together with admixed unvaporized oil introduced into the said reflux tower to the pressure distillation.

10. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-contained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors to condensation, and supplying admixed condensate and unvaporized fresh oil from this tower to the pressure distillation without substantial reduction in temperature.

11. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressureat cracking temperatures in which unvaporized oil is Withdrawn from the pressure distillation during operation and subjected to further vaporization by its self-contained heat through reduction in pressure, the improvement which comprises taking off vapors from the pressure distillation and condensing them to form a pressure distillate, subjecting the vapors separated from the unvaporized oil withdrawn from the pressure distillation to a fractionating operation, and controlling the fraotionating operation by supplying thereto portions of the final distillate product recovered from the vapors taken 01f from said fractionating operation to permit taking off as vapors from the fractionating operation a fraction containing constituents which correspond to the components of said distillate product.

12. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils 'by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn from the pressure distillation during operation and subjected to further vaporization by its self-contained heat through reduction in pressure, the improvement which comprises taking off vapors from the pressure distillation and condensing them toform a pressure distillate, subjecting the vapors separated from the unvaporized oil withdrawn from the pressure distillation to a fractionating operation, facilitating said fractionating operation by supplying thereto portions of the final distillate products recovered from vapors taken off from said fractionating operation.

13. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-contained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower,

so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors to condensation, passing the vapors from the pressure still into a reflux tower and introducing admixed condensate and unvaporized fresh oil from the first mentioned tower into direct contact with the vapors therein, returning reflux together with admixed unvaporized oil from the said reflux tower to the pressure distillation, and returning portions of the distillate products of the process to said towers.

14. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-contained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower, so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors tocondensation, passing the vapors from the pressure still into a reflux tower and introducing admixed condensate and unvaporized fresh oil from the first mentioned tower into direct contact with the vapors therein, returning reflux together with admixed unvaporized oil from the said reflux tower to the pressure distillation, and returning portions of the distillate product recovered from the vapors taken off from said first mentioned tower, back to said first mentioned tower.

15. In processes of cracking higher boiling hydrocarbon oils to produce lower boiling hydrocarbon oils by distillation under pressure at cracking temperatures in which unvaporized oil is withdrawn during the pressure distillation and subjected to further vaporization by its self-con- Y tained heat under a reduced pressure, the improvement which comprises passing the vapors separated from the oil withdrawn from the pressure distillation into a tower, introducing fresh oil directly into the vapor space in this tower so as to bring the fresh oil and vapors into direct and intimate contact therein, thereby subjecting the vapors to condensation, supplying admixed condensate and unvaporized fresh oil from this tower to the pressure distillation without substantial reduction in temperature, and returning a portion of the distillate products recovered from vapors removed from said tower into said tower.

16. A process for cracking hydrocarbon oils, consisting in heating the oil to a conversion temperature while passing the oil in a continuously advancing stream through a heating zone, in directing the highly heated oil successively through a plurality of enlarged chambers serially connected, in separately drawing off the vapors evolved in each of said chambers, in subjecting the vapors to dephlegmating and condensing actions, in maintaining decreasing pressure conditions in each of the successive chambers, in returning reflux condensate resulting from the dephlegmating action of the vapors issuing from the chamber maintained under the lowest pressure to act as a dephlegmating medium for the vapors issuing from a chamber maintained under a higher pressure, and in returning the reflux condensate resulting from the dephlegmation of the vapors issuing from the chamber maintained at the highest pressure under a mechanically applied pressure to said stream.

17. A continuous process for cracking hydrocarbon oil, consisting in raising the oil to a cracking temperature, while flowing in a stream through a heating zone, in delivering the heated oil from said stream to the first of a plurality of serially connected enlarged vapor chambers, in separately removing vapors evolved from the oil from each of said chambers, in subjecting the vapors removed from the first to the last of said series of chambers to dephlegmation under successively lower pressure conditions, in utilizing the reflux condensate separated from the vapors evolved in one of said chambers of the series as a dephlegmating medium for the vapors evolved in a preceding chamber of the series, and in returning the reflux condensate separated from the vapors evolved in the first chamber of the series to said stream for retreatment.

18. A hydrocarbon oil cracking process which comprises passing a stream of the oil through a heating zone and subjecting the same therein to cracking conditions of temperature and pressure, discharging the heated oil into a vapor separating zone wherein a separation of vapors and unvaporized oil takes place, separately withdrawing vapors and unvaporized oil from said vapor separating zone, dephlegmating said vapors thereby forming reflux condensate, returning said reflux condensate directly to said heating zone, passing said unvaporized oil to a second vapor separating zone wherein a further separation of vapors and unvaporized oil occurs, withdrawing vapors from said second vapor separating zone and subjecting the same to dephlegmation thereby forming additional reflux condensate, and utilizing said additional reflux condensate as a dephlegmating medium in the dephlegmation of the vapors withdrawn from the first mentioned vapor separating zone.

19. An oil cracking apparatus comprising a heating coil disposed within a furnace, a vapor separating chamber communicating with said coil, a second vapor separating chamber connected to the first mentioned chamber, a first dephlegmator communicating with said first mentioned chamber and a second dephlegmator communicating with said second chamber, and means for introducing reflux condensate from said second dephlegmator to said first dephlegmator or for passing the same directly to said coil.

20. An oil cracking apparatus comprising a heating coil disposed within a furnace, a vapor separating chamber communicating with said coil, a second vapor separating chamber connected to the first mentioned chamber, a first dephlegmator communicating with said first mentioned chamber and a second dephlegmator communicating with said second chamber, means for introducing charging oil into the upper portion of said second dephlegmator, means for-removing liquid from the lower portion of said second dephlegmator and for introducing the same to the upper portion of said first dephlegmator, and means for passing liquid from the lower portion of said first dephlegmator to said coil.

21. An oil cracking apparatus comprising a heating coil disposed within a furnace, a plurality of serially connected vapor separating chambers communicating with said coil, a separate dephlegmator connected to each of said chambers, means for selectively introducing charging oil to the upper portion of the dephlegmators, and

means for passing liquid from the lower portion of each of said dephlegmators to said coil.

22. An oil cracking apparatus comprising a heating coil disposed within a furnace, a vapor separating chamber communicating with said coil, a second vapor separating chamber connected to the first mentioned chamber, a first dephlegmator communicating with said first mentioned chamber, and a second dephlegmator communicating with said second chamber, means for introducing charging oil to the upper portion of said second dephlegmator, and means for passing liquid from the lower portion of said second dephlegmator to said coil, means for introducing liquid from the lower portion of said second dephlegmator into the upper portion of said first dephlegmator, and means for passing liquid from the lower portion of said first dephlegmator to said coil.

23. An oil cracking apparatus comprising a heating coil disposed within a furnace, a plurality of serially connected vapor separating chambers communicating with said coil, a separate dephlegmator connected to each of said chambers, means for selectively introducing charging oil to the upper portion of the dephlegmators, and means for passing liquid from the lower portion of each of said dephlegmators to said coil, and means for passing liquid from the lower portion of a dephlegmator connected to one of said chambers into the upper portion of the dephlegmator connected to the preceding chamber of the series.

24. An oil cracking apparatus comprising a heating coil disposed within a furnace, a vapor separating chamber communicating with said coil, a second vapor separating chamber connected to the first mentioned chamber, a first dephlegmator communicating with said first mentioned chamber, and a second dephlegmator communicating with said second chamber, means for introducing charging oil to the upper portion of said second dephlegmator, means for passing liquid from the lower portion of said second dephlegmator to the upper portion of said first dephlegmato and means for passing liquid from the lower portion of said first dephlegmator to said coil.

CARBON P. DUBBS.

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