US1975315A - Process and apparatus for treating oils - Google Patents

Description

Oct. 2, 1934. c. P. DUBBS PROCESS AND APPARATUS FOR TREATING OILS Original File d June 22. 1921 i l/Ml Carbon P2111255.

Patented Oct. 2, 1934 UNITED STATES PATENT OFFICE Carbon P. Dubbs, Wilmette, 111., assignor to Universal Oil Products Company, Chicago, 111., a

corporation of South Dakota Application June 22, 1921, Serial No. 479,444

8 Claims.

This invention relates to improvements in process and apparatus for treating oils and refers more particularly to a process in which the oil, after being cracked under pressure, is separated .5 into a liquid and vapor portion, the vapors being refluxed and condensed into pressure distillate vwhile the liquid portion is directed at a reduced or atmospheric pressure, to a dephlegmating zone of reduced pressure and the vapors formed due to this reduction in pressure refluxed and condensed as a separate distillate; to provide a process in which the distillates collected may be returned and introduced with the raw oil as a refluxing medium to either or both of the refluxing stages and a process in which regulated quantities of the reflux and raw oil may be returned to the primary heating zone for treatment; to provide a process in which an increased yield is procured and distillates of a more uniform character separated from the oil body and to provide an apparatus for carrying out this process.

The single figure is a diagrammatic side elevational view of the apparatus.

In the cracking of hydrocarbon oils as it is commonly practiced, by pressure distillation, there is a. considerable quantity of relatively high boiling point cuts or fractions carried ofi with the residuum in liquid form, which could easily be relieved from the residuum and both increase the yield and further supply a liquid distillate which it is possible to return to be reheated and cracked into desirable marketable products. In the process herein disclosed, the residuum drawn from the vaporizing chamber is directed to a refluxing zone under reduced pressure and there the vapors which separate under the reduced pressure, are refluxed and pass over to a separate condenser and receiver.

Referring in detail to the drawing, the raw oil is introduced from any extraneous source through the inlet pipe 1 and may be charged through the line 2 controlled by a valve 3 and pumped by means of the pump 4 and line 5 to the top of the secondary dephlegmator 6 or directed to the line '7 regulated by a valve 8, and introduced to the heating coils 9 through the pump 10 and line 11 in which is interposed a valve 12. By closing the valve 12, the oil may be forced through the vertical line 13 regulated by a valve 14 and introduced into the primary dephlegmator 15 where it serves as a cooling medium in refluxing the oil vapor. By controlling valves 12 and 14 regulated quantities of raw oil may be directed to the dephlegmator 15 and coil 9. In its travel through the dephlegmator 15, the oil will reflux out higher boiling point condensates and carry them with the raw oil down through the return line 16 regulated by a valve 1'7 which is connected to the line 11, which leads to the heating tubes. The heating tubes are mounted in the furnace 18, preferably heated by means of gas burners 19. After being raised to a cracking temperature in the heating zone, the oil passes to a vaporizing chamber 20 through the transfer line 21, controlled by a throttle valve 22. In the vaporizing chamber the oil body is converted into a vaporized portion which passes over through the vapor line 23' to the dephlegmator 15 and a liquid or residual portion which is drawn off through the line 24 in which is interposed a valve 25. The vapors passing through the dephlegmator 15 are refluxed by the raw oil as explained and pass over through the line 26 to a water condenser coil 27, thence to a receiver 28 in the form of pressure distillate. The pressure on this portion of the system may be accurately regulated by means of the pressure relief valve 29. The liquid or residual portion from the vaporizing chamber 20 is conducted through the line 24 and is introduced into the bottom of the secondary dephlegmator 6.

Itwill be noted that there is a substantial reduction of pressure between the vaporizing chamher and the secondary dephlegmator which is accurately controlled by means of the valve 25. This reduction of pressure will vary according to the distillate desired and may range from any pressure slightly less than that maintained in the primary system down to atmospheric. The residual liquid oil on passing to the reduced pressure zone in the dephlegmator 6 releases therein vapors which rise in the dephlegmator and pass over through the line 30 to the water condenser 31 and receiver 32 in the form of a separate distillate. The still liquid portion which collects in the bottom of the dephlegmator 6 is drawn off through the line 33 and may be transferred to storage through the pipe 34 controlled by a valve 35 or may be directed by the pump 10 back through the connecting 'line 36 regulated by a valve 37. It will be noted that the raw oil is introduced to the tops of both of the dephlegmators as a refluxing medium. The separate distillates collect in the receiving tanks and maybe Q drawn ofl? through the valves 38 and 39 respectively or by introducing the distillates through the valves 40 and 41 to the pump 42 they may be combined and charged through the line 43 to the top of the dephlegmators where separate leads 44 and 45 controlled by valves 46 and 47 respectively permit the introduction of regulated quantities of combined distillate to the top of either or both of the dephlegmators. The connections are such that the distillates may be combined and pumped back into the top of either or both of the dephlegmators or each distillate in turn may be separately returned and charged to the dephlegmator desired.

The particular method of operation will vary with difierent factors involved, that'is, operating conditions may be such that it will be desirable to return only the distillate procured from vapors released in the secondary dephlegmator. In such a case the distillate from the receiving tank 32 may be pumped back separately and the distillate from the receiver 28 drawn ofi through the valve 38. At another time, it may be advantageous to the operation of the process to return the combined distillate and introduce it into either the primary or secondary dephlegmator alone and in such case, the valves must be so manipulated as to afiect the returning of the distillate in this manner.

It will also be noted that the pump 10 is so connected in the system that the liquid portion from the secondary dephlegmator when not drawn off to storage will be charged with the raw oil to the top of the primary dephlegmator or it may be charged directly with the raw oil through the line 11 to the heating tubes. Numerous variations in the directing of both the raw oil and pressure distillate may be effected and the temperature control in the dephlegmating columns thereby accurately regulated.

In treating Mid-Continent gas oil of approximately 30 to 32 Baum at a temperature from 700 to 900 degrees F., and a pressure of from 100 to 500 pounds, vaporizing, refluxing and condensing the vapors released in the vaporizing chamber and transferring the residuum to a zone of reduced pressure and separately refluxing and condensing the Vapors released therein, it is possible to produce a high grade pressure distillate of approximately 50 to 52 degrees Baum from the primary distillation and a distillate of some lower gravity in the second distillation stage varying, of course, with the reduction of pressure in the secondary zone and other factors such as the temperature in the refluxing and condensing stages.

I claim as my invention:

1. A process for treating oil, consisting in cracking the oil under a substantial pressure in a heating and vaporizing zone, dephlegmating, condensing and collecting the generated vapors, directing the unvaporized portion to a separate dephlegmating zone and there distilling it at a reduced pressure, condensing and collecting the vapors produced thereby separately, and returning the distillate from the separate condensing zones to the dephlegmators.

2. A process for treating oil, consisting in cracking the oil under a substantial pressure in a heating and vaporizing zone, dephlegmating and condensing the generated vapors, passing the unvaporized portion from the vaporizing zone, to a separate dephlegmating and condensing zone and there vaporizing it at a reduced pressure and collecting the distillates produced in the two zones of condensation and returning them separately to either dephlegmating zone.

3. In anapparatus for treating oil, the combination with heating and vaporizing means for cracking the oil under pressure, of dephlegmating means connected with the vapor and the liquid drawoffs from the vaporizing means, separate condensing and collecting apparatus connected to each dephlegmator, means for returning the distillate produced to both dephlegmating means and means for maintaining a reduced pressure in the dephlegmating and condensing means connected with the liquid drawofl from the vaporizing means.

4. A process of treating hydrocarbon oils, consisting in raising the oil to a cracking temperature in a heating zone under a superatmospheric pressure, in introducing the oil to an enlarged vapor chamber where a substantial portion thereof vaporizes under a superatmospheric pressure, in passing said vapors to a dephlegmator, in passing unvaporized oil from said vapor chamber to a second dephlegmator while said oil is in a highly heated condition, in substantially reducing the pressure on the oil in saiddephlegmator while it is sufliciently hot to cause a vaporization of a substantial portion thereof under such reduced pressure, in separately discharging and separately condensing the vapors from said dephlegmators, and in introducing the distillate obtained to said dephlegmators to assist in condensing the heavier oil fractions.

5. A process of treating hydrocarbon oils, consisting in raising the oil to a cracking temperature in a heating zone under a superatmospheric pressure, in introducing the oil to an enlarged vapor chamber where a substantial portion thereof vaporizes under a superatmospheric pressure, in passing said vapors to a dephlegmator, in passing unvaporized oil from said vapor chamber to a second dephlegmator while said oil is in a highly heated condition, in substantially reducing the pressure on the oil in said dephlegmator while it 119 is sufficiently hot to cause a vaporization of a substantial portion thereof under such reduced pressure, in separately discharging and separately condensing the vapors from said dephlegmators, in introducing the distillate obtained to said dephlegmators to assist in condensing the heavier oil fractions, and in then returning unvaporized distillate with reflux condensate to the cracking zone for retreatment.

6. A continuous process of cracking oil comprising circulating oil in a closed cycle circuit, cracking the oil by distillation under a high pressure and temperature in one portion of the circuit,' distilling the' residual oil from said cracking by evaporating it under a reduced pressure in another portion of the circuit, and separately collecting condensate from the distillations in the difierent portions of the circuit.

7. A continuous process of cracking oil comprising circulating oil in a closed cycle circuit, cracking the oil by distillation under a high pressure and temperature in one portion of the circuit, evaporating the residual oil from said cracking by distillation under a reduced pressure in another portion of the circuit, separately collecting condensates obtained from the distillations in the different portions of the circuit, introducing oil into the cracking portion of the circuit, and applying heat only to the oil being introduced into the cracking portion of the circuit.

8. An oil distilling apparatus comprising a pipe still, a cracking chamber, means for forcing oil from the pipe still into the cracking chamber, an evaporator connected with thecracking chamber, a condenser connected with the evaporator, means to conduct condensate to the pipe still, a conductor for leading oil from the evaporator back to the cracking chamber, and a condenser connected with the cracking chamber.

CARBON P. DUBBS.

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