US2158962A - Hydrocarbon oil conversion - Google Patents

Description

. May 1s, 1939. 'c p, DUBBS y2,158,962

lI'IYDRGARBON OIL CONVERSION original Filed March 7,".1927

fyi/mei' IEEE/12F Patented May 16, 1939 UNITED STATES PATENT OFFICE HYDROCABBON OIL CONVERSION ware Application March 7, 1927, Serial No. 173,269 g Renewed May 7, 1937 4 Glaims. (Cl. 196-49) 'Ihe present improvements relate more particul-arly to the conversion of hydrocarbon oils under cracking conditions of conversion temperature and superatmospheric pressure. f The invention is characterized primarily by its flexibility, permitting either a high yield of gasoline-like products and a low yield of non-vaporous residue, or a low yield of gasoline-like products and a large yield of non-vaporous residuum, including the ranges therebetween. l

In different parts` of the world, and particularly in the United States, different market cony ditions prevail, making it advisable from an economic standpoint in oner locality to produce a large yield of gasoline-like products and a low yield of residue suitable for fuel. Conditions in another part of the country may be directly the opposite, and it may be advisable to produce a highyield of residue suitable for use as fuel.

The present invention has been particularly designed to permit a standard process and apparatus to be utilized `in different parts of the country and operated under widely variant conditions. The invention is further characterized by its ability to satisfactorily operate on difierent kinds of charging stock, embracing a range from heavy residue of low Baum gravity up to and including kerosene-like material having a relatively high gravity, say 40 Baume, more or less. It is well known that different operating conditions must prevail for different types of charging stock, depending on the products desired, and the Apresent invention has been particularly designed to embrace in a single unit, process and apparatus which would operate efficiently under all these widely' variant conditions.

The utility, as well as many other objects and advantages, will be more apparent from the following description.

In the drawing, the single figure is a diagrammatic or schematic view or flow-chart illustrating the invention.

In the drawing, the charging stock is fed from the charging stock storage receptacle I through the line 2, in which may beinterposed a pump 3, meter 4 and valve 5. When the valve k5 is opened, the oil passes up through the line 2 into a closed coil 6, positioned in the upper part of a dephlegmator 1. This coil 6 may be by-passed if desired by closing 'the valves 8 and opening the valve 9 in the by-pass line I0. In either event, lthe charging stock is eventually delivered to the yreturn line II', in which maybe interposed a valve I2. This return line YII passes the oil through a closed coil I3, positioned in a heat exchanger I4, from which it may pass through a line I5, controlled by valves I6 and I1 into a vapor separator I8. As a feature of the invention, this vapor separator may preferably comprise a nar- 5 row vertically disposed chamber, having a very limited capacity, wherein vapors that may be formed in the pre-heated charging stock may be released, passing through the vapor line I9, controlled by valve 20, into the interior of the 10 dephlegmator 1. Vapors thus formed, which, of course, comprise the low boiling constituents of the charging stock, are thus conveyed directly into the dephlegmator 1 and are not forced into the suction of the hot oil pump.

The unvaporized portion is removed from the vapor separator I8 through the line 2l, in which may be interposed the hot oil pump 22, said line 2l forwarding the pre-heated charging stock t0 the heating tube 23, mounted in a furnace 24. H In passing through the heating tube 23, the charging stock is raised to a conversion temperature, which, depending upon the condition of operation', may vary widely from '150 to 1000 F., more or less. The heated oil is transferred through the transfer line 25, in which may be interposed a valve 26, into a reaction chamber 21, where vapor separation takes place. The heating tube 23 and reaction chamber 21 are maintained under a relatively high superatmosu pherie pressure, for instance, from 100 to 30,00 pounds, more or less. 'Ihe vapors separating in the reaction chamber 21 pass out through vapor outlet line 28, controlled by valve 29, being introduced into the lower section of the dephlegmator 1 below the partition 30 and above the partition 3|, the vapors passing from this compartment through the open-ended uprights '32 into the interior of the dephlegmator 1, where they are subjected to the usual reflux condensing action, being cooled by means of the charging stock, which may or may not be introduced through the coil 6 or by returning regulated portions of the distillate introduced through the line 33, as will shortly be explained. 'I'he vapors remaining uncondensed after passage through the dephlegmator pass out through the vapor outlet line 34, in which may be interposed a valve 35, being condensed in a suitable instrumentality, diagrammatically illustrated 5 and designated 36, collecting as liquid distillate in the distillate receiver 31. This receiver may be provided with the usual gas relief pipe 38, controlled by valve 39, and with liquid draw-off line 40, controlled by valve 4I. Regulated portions of 55 the distillate lfrom the receiver 31 may be returned through the line 33, in which may lbe interposed the pump 42, to the dephlegmator.

A draw-off 43, controlled by valve 44, may be provided for withdrawing any condensate from the compartment formed between partitions 30 and 3i in the dephlegmator 1.

Returning to the reaction chamber 21, th non-vaporous residue may be withdrawn through any one or more of the lines 45, in which may be interposed valves 46, merging in a common header or transfer line 41.` This transfer line 41 may divert the residue through the line 48, controlled by valve 49, which line 48 communicates with the heat exchanger I4, from which the residuum may be Withdrawn through line 50, cooled in an instrumentality illustrated diagrammatically at 5|, and collected in the residuum storage receptacle 52.

Or if desired,'the valve 43 may be totally or partially'closed -and all or a regulated portion of the residue diverted through the line 53, controlled'by valve 54, discharging into the interior of a flash chamber 55. The valves 46, 49 and'54 are preferably pressure reducing valves, so that the residue which has been withdrawn from the reaction chamber 21 under the superatmospheric pressure maintained therein may have `its pressure considerably reduced or released altogether; thus, when being introduced to the flash chamber 55, a very substantial portion Aof it Will vaporize, due to its latent heat. Vapors which separate in the flash chamber 55 may pass out through the line 55, controlled by valve 51, into the interior of the dephlegmator' 1,'Where theycombine with the vapors coming Vdirectly from the reaction chamber through vapor line 28, and are subjected to similar reflux condensation. It may be pointed out here that the valve 29 in vapor transfer line 28 is preferably a pressure reducing valve, in order that the high pressure maintained in the chamber 21 may be considerably reduced or released altogether, so that the dephlegmator 1 operates under a lower pressure than the tube 23 and reaction chamber 21.

Reflux condensate collects in a body on the partition 30, as illustrated at 58, being withdrawn through the line 59 into the Vapor separator I8, so that the reflux from the dephlegmator and unvaporized charging stock are united and forwarded through the line 2| to the heating tube 2'3 for heating. Suitable liquid draw-offs are provided on the side wall of the dephlegmator, as illustrated diagrammatically at 6G, controlled by Valves 6I, to determine the liquid level of reflux condensate for the purpose of control. It, of course, is apparent that While I have shown the dephlegmator 1 and Vflash chamber 55 as a Ysingle instrumentality separated by the partitions 30 and 3l, that they may be separate instrmnentaIitieS, if found more desirable.

The arrangement is such that reboiling of the reflux condensate collected in the pool illustrated vat 58 takes place dueto the heat of the vapors passing upwardly through the open-ended up- ,rights'32. f

`Residue rfrom the flash chamber 55 may be Withdrawn through the line 62 diverted through .line 63,- controlled by valve 64, cooled in cooling instrumentality designated 65, and collected in anyrsuitable storage, orvalve 64 may be closed and valvef in draw-off line 61 opened to divert Describing now a feature of the present invention, I illustrate a number of Ways for controlling 'the gravity of the residue withdrawn, which control is important in the production of a residue suitable for use as fuel. One method of controlling the gravity of the residue is, of course, by control or variation of the pressure maintained in the flash chamber 55, which can be controlled, of course, by the valves sho-wn in the drawing.

Or this gravity may be controlled by introducing a regulated portion of the raw oil directly into the residuum line at the point where the residuum is released from the reaction chamber. This is accomplished by manipulating the valve 68 in the branch 69, thus diverting a small portion of the raw oil into the line 10, controlled by valve 1 I, which merges with the residue drawoff line 41 from the reaction chamber 21. This mixturerof a controlled quantity of the raw oil with the residue withdrawn from reaction chamber 21 will lower the temperature of the residue and thereby control the amount of vapors released in the flash chamber 55.

Or as an alternative, a portion of the raw oil feed, before passing through the pre-heating coil 6 in the top of the dephlegmator can be diverted through the cooling coil 12, located in the upper section of the flash chamber 55, having connecting lines v13, controlled by valves 14, so as to condense some of the heavy 'ends of the vapors released in the flash chamber 55, thus changing the gravity of the withdrawn residue.

As another feature of the invention, the vapors being introduced into the dephlegmator 1 through the vapor -line 28, on account of being released from the high pressure maintained in the Vreaction chamber 21, will be in a superheated state, and possibly from 100 to 150 higher in temperature than they normally Would be if vaporized at the pressure carried in the dephlegmator. This heat is available for heating the reflux collecting in the pool 58, thus stripping any light ends in the reflux and permitting only the heavier ends of the reflux to be withdrawnthrough the pipe 59 and returned to the cracking tubes 23.V For the purpose of diverting reflux, if for any reason it should be found desirable, I provide the emergency line 15, controlled by valve 16.

It lwill be apparent to those vskilled in the Vart that suitable apparatus for carrying out the invention diagrammatically illustrated inthe drawing is to be used. The plant may be operated to produce a large yield of residual oil suitable for use as fuel, the gravity of which canbe very carefully controlled, and a low yield of gasoline, while also permitting by obvious manipulation an operation and process to -be carried on, in which a low yield of residue is produced and a high yield of gasoline. In case a large .yield of residue is produced, itis advisable to-pre-heat the incoming raw oil in the coil I3 by means of the outgoing residue. Should it be found desirable to by-.pass

the coil I3, the valves I2 and I6 are closed and the valve 11 in line '18 opened. If it should be found desirable topartially pre-heat the raw oil being diverted through theline A1li to mix with the residue withdrawn through the liner 41, the valve 19I in line v80 may be manipulated to pass the preheated raw oilinto the line 10. A branch 8Icontrolled by valve 82 also permits the raw oil after it has been pre-heated by passing through the closed coil-6 lto bediverted yinto thelinel.

It mayin Ysome instances be desirableto makev in this plant a so-called non-residuum run,

that is, with a maximum yield of vapors which are condensed into gasoline-like products, and a minimum or negligible production of liquid residue, it being the purpose to convert the charging stock mainly into two products, vapors and a substantially non-flowing coke-like residue. In such an instance, it may be found desirable anyway to flash the residue from reaction chamber 21 in the flash chamber 55 and relieve it of its light fractions in the form of vapors, in order to avoid a decrease in the capacity of the plant.

In order to permit such an operation, I provide additional draw-offs from the flash chamber 55, designated 83 and 84, respectively, controlled by valves 85 and 86. The proper manipulation of valves 85 and 86 will divert controlled quantities of the residue through the line 81, in which may be interposed a hot oil pump 88, returning the residue either through a continuation 89 of the line 81, controlled by valve 9D, to the transfer line 25, or diverting same through the branch 8 I, controlled by valve 92, directly into the reaction chamber 21.

In operating the plant for this purpose, it is desirable that the smallest deposit of coke be had in the flash chamber 55, while most of the carbon will collect in the reaction chamber 21. Some coke may deposit in the flash chamber 55, hence I have illustrated the additional draw-off 83 at a Yhigher level, which it is to be understood may be utilized for either returning the residue to the line 81, or passing it to storage through the line 48 by obvious manipulation of valves.

From the foregoing, it will be apparent that I have perfected a very efficient and scientifically designed method, in which any type of charging stock differing widely in characteristics may be handled, and which method may be carried out under any desired efficient operating conditions to produce a maximum yield of the type of product desired. The flexibility of the plant has been emphasized in the foregoing description.

I claim as my invention:

1. In the art of hydrocarbon oil conversion, steps which comprise subjecting hydrocarbon oil to cracking conditions of temperatur-e and superatmospheric pressure, discharging the heated oil into an enlarged zone where substantial vaporization occurs, separating the vapors from the nonvaporous residue, in removing said separated vapors and subjecting same to cooling action, separately withdrawing the non-vaporous residue, substantially reducing the pressure maintained on said non-vaporous residue and passing same to a zone where vaporization is effected due to sensible heat, separating resultant vapors and separately withdrawing the remaining non-vaporous residue from thevsecond mentioned zone and returning portions thereof to said heated oil prior to vaporization thereof.

2. In the art of hydrocarbon oilconversion, steps whichcomprise subjectinghydrocarbon oil to cracking conditions of temperature and superatmospheric pressure, discharging the heated oil into an enlarged zone where substantial vaporization occurs, separating the vapors from the non-vaporous residue, in removing said separated vapors and subjecting same to cooling action, separately withdrawing the non-vaporous residue, substantially reducing the pressure maintained on said non-vaporous residue and passing same to a zone where vaporization is effected due to sensible heat, separating resultant vapors and separately withdrawing the remaining non-vaporous residue from the second mentioned zone and returning portions thereof to said heated oil prior to vaporization thereof, combining the vapors from the cracking and flash distillation steps, subjecting them to common deplegmation and final condensation.

3. In the art of hydrocarbon oil conversion, steps which comprise subjecting hydrocarbon oil to cracking conditions of temperature and superatmospheric pressure, discharging the heated oil into an enlarged zone where substantial vaporization occurs, separating the vapors from the nonvaporous residue, in removing said separated vapors and subjecting same to cooling action, separately withdrawing the non-vaporous residue, substantially reducing the pressure maintained on said non-vaporous residue and passing same to a zone where vaporization is effected due to sensible heat, separating resultant vapors and separately withdrawing the remaining non-vaporous residue from the second mentioned zone and returning portions thereof to said heated oil prior to vaporization thereof, combining the vapors from the cracking and ash distillation steps, subjecting them to common deplegmation and nal condensation, cooling the vapors in said deplegmation step by passing charging cil in indirect heat interchange relation out of physical contact therewith, and returning the final condensate in direct physical contact therewith.

4. A hydrocarbon oil conversion process which comprises heating charging oil for the process to distillation temperature and introducing the same to a vapor separating zone wherein vapors are separated from unvaporized oil, introducing the vapors to a fractionating zone containing vaporous products formed as hereinafter set forth, fractionating the commingled vapors in the fractionating zone to condense heavier fractions thereof, combining resultant reflux condensate with unvaporized portion of the charging oil separated in said separating zone, subjecting the thus commingled oils to cracking conditions of temperature and pressure in a heating coil and then discharging the same into a second separating zone maintained under pressure, separately removing vapors and liquid from the second separating zone and ash distilling the liquid by pressure reduction in a flashing zone independent'of said separating zones and commingling residual oil from the ashing zone with the heated products discharging from said coil into the second separating zone, introducing resultant flashed vapors from the flashing zone and vapors removed from the second separating zone to the fractionating zone as said vaporous products, and finally condensing the fractionated vapors.

CARBON P. DUBBS.

Images