US2009878A - Process for treating hydrocarbon oil - Google Patents

Description

July 30, 1935. c. P. DUBBS PROCESS FOR TREATING HYDROCARBON OILS NN .WN

Wfl??? 655 Patented July 30, 1935 UNITED STATES PATENT OFFICE Carbon P. Dubbs, Wilmett Universal OilProducts a corporation of South Dakota Application February 12, 1923, Seri Renewed May 10,1933

4 Claims.

e This invention relates to i process for convertin and refers more parti tillation of petroleu the lighter oil cons similar to gasoline.

Among the salient objects of the invention are to provide a process in which oil is treated under pressure and the lighter hydrocarbons separated therefrom in the form of pressure distillate. Simultaneously with this processing of the hydrocarbon, there is introduced to the system, a second charging stock which Ais separately treated, the heat of the initial system being utilized to preheat the secondary charging stock, whereby a considerable economy of fuel is effected; to provide a process in which the distillates from the separate charging stocks are separately collected, and one in which an accurate 20 temperature control may be kept upon the diierent stages of the two separate systems; to provide an improved type of apparatus for carrying out this process The single figure is mprovements in a g petroleum hydrocarbons, cular-ly to the pressure dism oils to extract therefrom tituents producing distillates a diagrammaticside elevational View of an apparatus suitable for practicing the process. Referring to the drawing, a charging stock is introduced from any convenient source through the line I and is charged by the pump 2 through the line 3 controlled by the valve 4 to the heating coils 5 positioned in the furnace (i.v After circulation through the coils, the oil is raised to a conversion temperature and is passed thence through the transfer line 1 regulated by the Valve 8 to the expansion chamber 9.

This expansion chamber is equipped with trycocks I 0 for ascertaining the liquid level in the chamber 'and residual drawoi lines II positioned at'diiferent heights on the chamber for withdrawing the residuum and unvaporized products from the system.

Valves I2 are interposed in the separate residual lines. The vapors evolved in the chamber passfoif through the line I3 controlled by the valve I 4 and are directed to a dephlegmator I5 through which they rise in a circuitous travel caused by the positioning of perforated plates in the column. The dephlegmated vapors pass off from the top of the refluxing column through the line I6 regulated bythe valve I1 to a heat interchanger comprising an upper header I8 and a lower header I9 connected by tubes 2s interposed between the two headers. About these tubes is a chamber enclosed by a casing 2| through which a cooling medium is circulated as hereinafter explained. The vapors afterA passe, 1'll., assignor to The Company, Chicago, Ill..

al No. 618,457

ing through this hea oi through the li t interchanger are drawn ne 22 controlled by the'valve 23 and after passing through the condenser coil 24, they are collected as liquid distillate in the receiving tank 25.

The receiving tank is relief valve 5 equipped with a pressure 26, pressure gauge 21, a liquidA level gauge 28 and a liquid drawoif line 29 controlled by a valve 30. The liquid distillate collected in the receiving tank 25 vmay be drawn oi through 10 K the pipe 3l in which is` interposed the Valve 32, this line communicating with the suction side of the pump 33. By means of this pump the distillate is recycled through the line 34 regulated by the valve 35 and charged into the top of the l5 dephlegmating column I5 through the spray pipe 36.

This distillate with what re may be flux condensate separated from the vapors due to the cooling ofthe air about the column, is collected 20 in the lower leg ofthe dephlegmator and may be drawn off through the pipe 31 regulated by the Valve 33 and recycled with the charging stock through the line 3 to the heating coils, or portions of it may be removed from the system 25 through the line 39 controlled by the valve 40. This removal from the system is only necessary should the combined distillate and reux condensate become excessive relative the amount of charging stock introduced to the system.

The process explained, is the initial or primary system in which the major portionr of the oil is treated. The secondary system is dependent upon the initial system for its existence, and utilizes the excess heat of the initial system.

Explaining now the functioning of the secondary system, the oil is charged from any convenient source through the line 4I and is introduced by means of the pump 42 into the casing 43 surrounding the tubes 44 of a second heat inter- 40 changer. -The medium circulating through these tubes will be obvious on further explanation of the apparatus.

The oil is withdrawn from the casing 43 and passes through the pipe 45 controlled by the valve 45 46 to the circulating space enclosed by the casing 2l about the tubes 2Q. In` this primary heat interchanger, the tubes 20 contain the heated oil vapors and therefore serve to transfer considerable quantities of heat to the oil circulating there- 50 about. After being preheated in this manner, the oil is withdrawn through the line 41,v regulated by the valve 48 and is passed through the coils 49 positioned in the flue 50 of the furnace. Y Here, the oil acquires further heat from the partially expended combustion gases passing from the bottom portion of the heating chamber of the furnace.

After passing through the coils i9 the oil has received sufficient heat to raise it to a conversion temperature and in this condition it is directed through the line 5| and may be introduced into the fractionating column 52 through either of the different vertically spaced pipes 53, 54 or 55 controlled by valves 50, The pipes 53, 54 and 55 terminate in perforated sprays whereby the fluid oil constituents are introduced to the fractionating column in a finely divided condition. Perforated pans are also positioned in the column to further disseminate the fluid oil constituents in order that they may be more completely treated by the returned distillate produced by condensation of the evolved vapors. The liquid oil constituents are withdrawn from the bottom of the column through the line 59 regulated by the valve 50, and the vaporous portions pass off from the top of the column through the line 6l controlled by the valve 62. The line El communicates with the upper header G3 of the secondary heat interchanger to which the secondaryfcharging stock is introduced. From the header 63 the vapors pass down through the tubes M to a lower header 6I, thence through the line 65 regulated by the valve 65 to a condenser coil 67 and finally collected as liquid distillate in the receiving tank 88. This receiving tank is equipped with'a pressure relief valve 68, a pressure gauge 10, a liquid level gauge H and a liquid drawoff line 12 controlled by the valve '13. A secondary drawoff line 14 connected to the pump 15 furnishes a means for recycling this secondary distillate back through the line 15, regulated by the valve 11 to the top of the fractionating column 52 where it is introduced in a finely divided condition by the circular spray 18.

The liquid products removed from the bottom of the fractionating column may be withdrawn from the system, or directed through the pipe 'IS regulated by the valve 80 to the charging line l of the primary or initial cracking system.

By utilizing the heat of the system in this manner, practically all of the heat generated in the system is utilized in converting the oil. Also, an accurate regulation of the temperatures in the separate stages may be obtained, and a uniform distillate produced with little loss due to excessive temperatures in different portions of the system. f

The secondary charging stock may be crude oil which is to be topped or it may be distillates obtained by pressure distillation of oils.

1t is obvious of course, that the less refractory oil can be converted in the secondary system, as the temperatures are somewhat lower than those obtained in the initial or primary stages.

By treating gas oil of approximately 32 Baume in the initial or primary system under pressures ranging from 50 to 200 pounds and temperatures ranging from 700 to 900 F., a high quality pressure distillate comprising substantially 50% to of the charging stock will kbe obtained of from 48 to 52 Baume gravity, while in the secondary system a crude oil may be successfully topped to produce 20% Ato 30% oi'high boiling point distillates.

I claim as my invention:

l. A combined cracking and topping process for the continuous treatment of charging oil and 5l' and 53 respectively.

source other than the crude oil, which comprises passing charging oil in a restricted stream through a heating zone and heating the same therein to cracking temperature Aunder pressure, introducing the heated oil to a vapor separating zone and effecting a separation of vapors from unvaporized oil therein, passing the vapors to a dephlegmating zone and condensing insufliciently cracked fractions therein, subjecting the vapors uncondensed in said dephlegmating zone to final condensation, simultaneously with the foregoing cracking operation heating a continuously advancing stream of the crude oil to the distillation temperature of lighter fractions thereof and utilizing in such heating waste heat of the aforesaid cracking operation, discharging the heated stream of crude oil into a fractionating zone maintained at a temperature adequate to permit said lighter fractions of the crude oil to go off as vapor,

lremoving and condensing said lighter fractions,

supp-lying heavier fractions of the crude oil separated in said fractionating zone, in admixture with reflux condensate from the dephlegmating zone and without passage through said dephlegmating and separating zones, to said heating zone to be raised to cracking temperature therein in admixtme with the charging oil.

2. A combined cracking and topping process for the continuous treatment of charging oil and crude oil, the charging oil being derived from a source other than the crude oil, which comprises passing charging oil in a restricted .stream through a heating zone and heating the same therein to cracking temperature under pressure, introducing the heated oil to a vapor separating zone and effecting a separation of vapors from unvaporized oil therein, passing the vapors to a dephlegmating zone and condensing insufficiently cracked fractions therein, subjecting the vapors uncondensed in said dephlegmating zone to final condensation, simultaneously with the foregoing cracking operation heating a continuously advancing stream of the crude oil to the distillation temperature of lighter fractions thereof and assisting the heating of the crude oil by passing the same in heat exchange relation with vapors formed in the aforesaid cracking operation, discharging the heated stream of crude oil into a fractionating zone maintained at a temperature adequate to permit said lighter fractions of the crude oil to go oi as vapor, removing and condensing said lighter fractions, supplying heavier fractions of the crude oil separated in said fractionating zone, in admixture with reflux condensate from the dephlegmating zone and without passage through said dephlegmating and separating zones, to said heating zone to be raised to cracking temperature therein in admixture with the charging oil. Y

3. A combined cracking and topping process which comprises passing hydrocarbon oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under pressure, introducing the-heated oil to a vapor separating zone and effecting a separation of vapors from unvaporized oil therein, passing the vapors to a dephlegmating zone and condensing insufficiently cracked fractions therein, subjecting the vapors uncondensed in said dephlegmating zone to final condensation, simultaneously with the foregoing cracking operation heating a continuously advancing stream of crude oil to the distillation temperature of the lighter fractions thereof and utilizing in such heating waste crude oil, the @berging Oil being derived from a. heat of the aforesaid cracking operation, discharging the heated stream of crude oil into a fractionating zone maintained at a temperature adequate to permit said lighter fractions of the crude oil to go off as vapor, removing and condensing said lighter fractions, supplying heavier fractions of the crude oil separated in said fractionating zone, in admixture with reux condensate from the dephlegmating zone and Without passage through said dephlegmating and separating zones, to said heating zone to be raised to cracking temperature therein.

4. A combined cracking and topping process which comprises passing hydrocarbon oil in a restricted stream through a heating zone and heating the same therein to cracking temperature under pressure, introducing the heated oil to a vapor separating zone and effecting a separation of vapors from unvaporized oil therein, passing the vapors to a dephlegmating zone and condensing insufiiciently cracked fractions therein, subjecting the vapors uncondensed in said dephlegA mating zone to final condensation, simultaneously with the foregoing cracking operation heating a continuously advancing stream of crude oil to the distillation temperature of the lighter fractions thereof and assisting the heating of the crude oil by passing the same in heat exchange relation with vapors formed in the aforesaid cracking operation, discharging the heated stream of crude oil into a fractionating zone maintained at a temperature adequate to'permit said lighter fractions of the crude oil to go off as vapor, removing and 'condensing said lighter fractions, supplying heavier fractions of the crude oil separated in said fractionating zone, in admixture with reux condensate from the dephlegmating zone and without passage through said dephlegmating and separating zones, to said heating zone to be raised to cracking temperature therein.

CARBON P. DUBBS.

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