US2091196A - Process for converting hydrocarbons - Google Patents

Description

C. P. DUBBS PROCESS FOR CONVERTING HYDROCARBONS Aug. 24, 1937.

Filed June 20v, 191s Hal i' 4 Sheets-Sheet 1 II l I I1 A @uw Aug. 24, 1937. Q P DUBBS `2,091,196

PROCESS FOR CONVERING HYDROCARBONS Filed June 20, ILS-18 4 Sheets-Sheet 2 C. P. DUBBS PROCESS FOR CONVERTING HYDROCARBONS Aug. 24, 193 7.

lElS 4 Sheets-Sheet 3 Filed June 20,

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4 Sheets-Shea@ 4 WATE Aug. 24, 1937.

-Patented Aug. 24, 1937 UNITED. STATES PATENT QFFICE PROCESS FOR CONVERTING HYDRO CARBONSl Wale Application June 2 0, 1918, sei-'lai No. 240,913

13 Claims.

This invention relates to improvements in process for converting hydrocarbons and refers more particularly to a process of converting heavy into lighter hydrocarbons such as gasoline like products.

5 Among the salient objects of the invention are to provide a process in which the oil is compelled to pass in a plurality of relatively small streams through the re or cracking zone and then through a larger chamber or chambers located outside of the re zone and forming the vapor or distilling zone; to provide a process in which the oil iscirculated rapidly through the re' zone and relatively slowly through the vaporizing zone; to provide a process in which the oil is circulated through the re zone in streams of progressively decreasing size to insure the highest economy of operation and most eiiicient cracking; to provide a process which permits of the use of relatively small pipes in the lire zone and'in which the deposition of carbon is substantially eliminated in that part of the apparatus which is subjected to the highest heat; to provide a process in, which the speeclof circulation of the oil can be regulated and in which the speed of the oil may be varied as desired; to provide a process in which the precipitated carbon is deposited in that part of the apparatus (located outside of the re zone; to provide a process in which a regulated quan` tity of oil is at alLtimes automatically supplied to the system to lprevent the pipes becoming dry; to provide a process in which the cracking, distilling and condensing can take place under the pressure of the generated vapors. In the drawings:

Fig. 1 is a side elevation of the apparatus with parts shown in dotted-lines. I

Fig. 2 is a view partly in plan and partly in horizontal section. Y 40 Fig. 3 is a transverse cross-sectional view.

Fig. 4 is a detailed view showing the aerial condenser and water condenser. Suitable legends and arrows are applied upon the face of the drawings, the arrows showing the direction of flow A 5 ofthe eu. i f f Referring to the drawings, I designates the furnace, in the re zone of which are mounted a plurality of sets of relatively-small pipes, 2, 3, 4 and 5 respectively. AThe iirst set, 2, may be of 11A inches in. diameter, the set 3 an inchirrdiameter, the set 4 three fourths inch'in diameter and the set 5 one half inch in diameter. The exact diameter o1' each set may of course varywith conditions .of operation but should lbe of the correct size relative to the desired speed, friction,

amount of vapors taken off, character of product desired, etc.

I have found in practice that the decrease in diameter is advantageoua'but .just what chemical changes take place dierent from having pipe of the same diameter I am unable to state.

These pipes are connected in series and each set is provided with a `pump 6, the connections from the coils to the pumps being controlled by suitable valves. The pump for the' largest sizey pipe or c`oil is connected to a'suitable source of A.bulk supply. Mounted above the cracking coils and located outside of the fire zone are four vapor chambers, 1, 8, 9, and Il) respectively, there being a vapor chamber for each of the cracking coils. These vapor chambers maytake the form of -ten inch pipes and are inclined somewhat downwardly toward the end of the apparatus at which they pumps are located. The vapor chambers are cons' nected at one end to the respective coils by pipes II and at their other ends to the corresponding pump bypipes I2. A vertical aerial condenser I3 having a suitable' connection'controlled by a valve Il is disposed in communication with each of said vapor chambers. The aerials are connected to the inclined pipes I5 leading to manifold I6 which in turn is connected by pipe I1 to.

the water condenser coil I8. The condenser I8 leads to receiving tank I9 having draw-off 2li which 'is controlled by valve 2l. Valves 22 are interposed in the reflux pipes I5 so that pres# sure can be regulated on the system as desired and a reux cut out of the system if desired. A baille 23 to restrict the passage of the vapors may be interposed, if desired, in the vapor chambers which are also provided with gauges 24and 25,. The small pipes are at all times filled with oil but ofcourse the vapor chambers will not be. To prevent the system going` dry by excess vaporization or otherwise, I provide means for automatically supplying the oilto the system. To this end, I provide a tank 2 6 containing oil and connected by pipe 21 to the pump 6, a valve 28 being interposed in the pipe 21. The oil in this tankis provided with a oat valve 29 the arrangements being suchv that as the oil in the vapor chambers gets below a certain level that the oil in the tank will automatically be delivered to the pump. The oil is supplied to tank 26 from pipe 29' from any suitable source of supply. As the vapor chambers freely communicate with the itank 26 through lines I2, vertical connecting wpipes 28, header 28b and draw-off line 21, the,

level in the tank and vapor chambers is substan-y tially the same when the valves in the line I2 and 21 are open. Connecting pipes from the bottom of the vertical lines i!!!a to the inlet side of the respective pumps 6 direct the oil from the tank 26 to be introduced to the system, thereby, keeping the oil level in the tank and vapor chambers substantially the same. sure of cold incondensable gas is maintained above the level of the oilrby connecting the tank to the gas outlet 30 of the receiving tank.

, The temperature and pressure to which the oil is subjected will vary with conditions, both with the character of the oil treated and with the desired gravity or end point to be obtained as Well as other conditions. The pressure may vary from 50 to several hundred pounds although in some cases the process may be operated at less than 50 pounds pressure, as for example 20 to 30 pounds. The temperature of the oil in the small tubeswill vary from about 400 F., more or less, to 1200 F., more or less.

It is impossible to give any specifically denite pressures and temperatures, as they vary with diierent oils, as will also the yield of gasoline. In addition, the yield of gasoline will vary, depending on what gravity and end point is desired. The fixed gases generated are led out of the system. 'Ihe percentage of gasoline produced may vary from 20 to 50 per cent, or more, of the original crude material used.

,The residue is drawn outof the' last vapor chamber through pipe 3l which is connected by pipe 32 to a fractionating still 33. This still 33 which operates at atmospheric pressure is connected with gooseneck 34, Water condenser 35 and receiving tank 36. Distillates from tank 36 are delivered through any suitable pipe and pumped (not shown) to the inlets of the small coils in any convenient manner. The pipe 32 is provided with a valve 31 set at a pressure under which the system is operated. In pipe 32 is interposed a tank 38. In this tank 38 is interposed a oat valve 39 which regulates the rate ofv flow of the oil from the pressure sealing tank 38 by controlling the quantity of oil discharged through the pipe 32, it being appreciated that this valve 39 is mounted at the inlet of said pipe 32 and serves is maintained at the given level in the tank 38.

so as to prevent the escape of pressure gases along with the discharging oil, it being apparent from Figure 4 thatithis level is always above the outlet pipe 32, and the oat valve merely functions to continuously allow a given stream of oil to discharge under normal operating conditions, and in cases of a sudden excess rise of the oil level, a

1 greater quantity of oilis discharged by a further raising of the floatr valve, The upper end oi! this chamber 38 is provided with 'a gas inlet pipe III which is adapted to receive the uncondensable 'raise and Whenever the pressure becomes sutilcient to operate valve v3'! permit the excess residue to pass into the f ractionating'still. The constructionis similar to thatshown in tank 2|.

A balancing pres- 'Ihe residue which goes into the fractionating still is there fractionally distilled and the distillates which go over into the condenser are again returned to the cracking system for retreatment.

The residue left in the cracking still will contain most of the precipitated carbon.

Although the operating conditions on the different types of oil will vary through quite an extensive rangel the conditions when operating on Mid-Continent gas oilare as follows:-By introducing gas oil of approximately 32 B. and heating the same to a temperature from approximately '700 to 900 F. while maintaining a pressure ranging from 50-200 pounds and by continuously circulating the oil and treating the residual oil from the vapor chambers as disclosed, I have been able to recover from 50 to 60% of the original oil charge in the form of distillate of approximately 51 B.

I claim as my invention:

1. A process of converting heavy into lighter hydrocarbons, which consists in causing the oil to pass in a relatively small stream through a cracking zone, and thence to a relatively large vapor chamber, passing the unvaporized oil from said vapor chamber `through the cracking zone in a stream of decreased diameter relative to the rst mentioned stream, in passing said oil and vapors from the last mentioned stream into a vapor chamber, in removing vapors therefrom, in passing the unvaporized oil from said vapor chamber in a stream of smaller diameter through the cracking zone and in thence introducing the same into a vapor chamber, in taking oi vapors from said chamber, in maintaining a pressure above atmospheric in the system, in taking olf the residue from the system and fractionally distilling it at substantially atmospheric pressure and returning the distillate obtained in said fractionation to the cracking zone for retreatment.

2. A process of converting heavy into lighter hydrocarbons, consisting in causing the oil to pass 'inia relatively small stream through a cracking zone and thence to a relatively large vapor chamber, in .passing the unvaporized oil from said vapor chamber through the cracking zone in a stream of decreased diameter relative to said rst in taking oil? vapors from said vapor chamber/s..

and condensing and collecting them, in maintain-'- ing'a pressure above atmospheric on the oil in the system, in taking oil the residue from the system and fractionally distilling it at substantially atmospheric pressure, and returning the distillate obtained in said fractionation to the i cracking zone for retreatment.

3. A process of converting heavy into lighter hydrocarbons, consisting in causing the oil to pass in a relatively small stream through a cracking zone and thence to a relativelylarge vapor chamber, passing lthe unvaporized oil from vsaid vapor chamber through thecracking zone in a stream of decreased diameter relativeto said first mentioned stream and thence into a relatively large vapor chamber, taking 01T vapors from said vapor chambers, in maintaining a pressure boveatmospheric on the oil in the system. and in automatically regulating the level of the oil in the system to prevent the tubes containing the oil from becoming dry.

4. An improvement in the art of pressure diatillation of petroleum oils for converting heavy into lighter hydrocarbons, which consists in continuously passing hydrocarbon oil in a Small ,75

chambers where said oil is maintained under cracking conditions of temperature and pressure, in discharging the vapors from said vapor chambers, in withdrawing the residue produced from the cracking of the oil, and in releasing the pressure on said heated residue when introduced to a still, in heating the residue in said still while under substantially atmospheric pressure to disl0 till o the lighter fractions thereof, and in re.

turning sai'd distilled fractions for further cracking.

5. The herein described method of treating hydrocarbon oil which consists in subjecting a body 15 of oil to heat and pressure, drawing of! the heavier .oil from the first body of oil toform a second body of oil also maintained under pressure, and reducing the pressure-on the second body of oil lto effect the distillation of a portion of said oil. 20 6. The herein described method of treating hydrocarbon oil which consists in subjecting a body of oil to heat and pressure to release vapors from the oil, drawing oil the heavier oil from the iirst body of oil and holding itunder pressure, reducing 25 the pressure on said heavier oil to effect the distillation of a portion of said oil, then cooling the distilled portion ofthe oil to liquefy the same, and then returning the resultant liquid to `the main body of oil for retreatment.

30 1. The herein described method of treating hy` drocarbon oils which consists in subjecting a body of oil to heat and pressure separately recovering released vapors from the oil, drawing oit the heavier oil from said body of oil and holding it D under pressure, and reducing the pressure on the heavier oil to effect a separation of its lighter constituents from its heavier constituents.

8. A conversion process which comprises subjecting a body of hydrocarbon oil to cracking 4 Conditions o! temperature and superatmospheric pressure, removing unvaporized oil from said body and maintaining it in a second body under superatmospheric pressure, and reducing the pressure on said unvaporized o'il to vaporize a substantial 45 portion thereof.

9. A conversion process which comprises sub- Jecting a body. of hydrocarbon oil to'cracking conditions of temperature and superatmospheric pressure in a cracking zone, separately removing vapors and unvaporized oil from said zone, maintaining a body of the withdrawn unvaporized oil under superatmospheric pressure in a second zone, and subsequently reducing the pressure on the unvaporized oil to vaporize a substantial portion thereof.

10. A conversion process whichcomprises subjecting a body of hydrocarbon oil to cracking conditions of temperatm'c and superatmospheric pressure, removing unvaporized oil from said body and maintaining it in a second body under superatmospheric pressure, reducing the pressure on said unvaporized oil to vaporize a substantial por- Y tion thereof and returning resultant vaporized portions to the, process for retreatment under cracking conditions.

11. A conversion process which comprises subjecting a body ofhydrocarbon oil to cracking conditions of temperature and superatmospheric pressure in a cracking zone, separately removing vapors and unvaporized oil from said zone, maintaining .a body of the withdrawn unvaporized oilv under superatmospheric pressure in a second zone, subsequently reducing the pressure on the unvaporized oil to vaporize a substantial portion I thereof, condensing the vapors evolved by the pressure reduction andreturning resultant condensate to the cracking zone. A

12. In the conversion of hydrocarbon oils wherein the oil is heated to cracking temperature ina restricted heating zone and then introduced into an enlarged zone maintained under superatmospheric pressure, the improvement which comprises removing unvaporized oil from said enlarged zone and maintaining a body thereof under superatmospheric pressure, andsubsequent 1y iiashfdis'tilling the unvaporized Aoil by pressure reduction.

13. In the conversion of hydrocarbon oils wherein the oil is heated to cracking temperature i a restricted heating zone and then introduced into an enlarged zone maintained under superatmospheric pressure, the improvement which comprises removing,unvaporized oils from said enlarged zone and maintaining a body thereof under superatmospheric pressure, subsequently flash distilling the unvaporized oil by pressure reduction, and returning resultant iiash distillate to the heating zone. v y

' CARBON P. DUBBS.

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