US1985440A - Method of treating oils - Google Patents

Description

- '0. cs. BRANDT METHOD OF TREATING OILS Dec. 25, 1934.

Filed Sept. 24, 1926 DAVID 6. BRANDT MW MM avwwntoz Ha l l l l l lHl 33 his TED ATES Patented Dec. 25, 1934 The present invention relates to'the cracking of heavier hydrocarbons to obtain lighter hydrocarbons therefrom and more particularly to the treatment of residuums produced during the cracking operation. The invention of the present application is an improvement upon my prior pending application Serial No. 124,320, filed July 23,1926. v M V i 'In my prior application I have disclosed a'process and apparatus for cracking oils'in which residuum is Withdrawn from a cracking chamber maintained under a high super-atmospheric pres sure, to a distillation chamber or concentrator where the pressure on the residuum is released and the distillation is carried'on by the potential heat of the mass; The distillate recovered in this operation'is pumped into a mixing chamber into which is also charged raw oil andreflux condensate from a reflux tower, the mixture being pumped to a heater where it is heated to the cracking temperature. H u u The important objects of the presentinvention are improvements in the proce'ssand'apparatus for treating thef'residuum withdrawn from the cracking cham'ber'by carrying out the distillation thereof without releasing the pressure; to avoid loss of heat due to the reduction in' the pressure on the residuum and to return'the resulting distillate to the cracking chamber solely "byjits own pressure head. H s

The novel features of'the present invention are pointed out with particularity in the appended claims. The invention itself; however; together. with further objects and advantages will be best understood from "the following;description taken in connection withthe' accompanying drawing in which': The figure is an elevational View, partly in section and diagrammatic ,in character, of an apparatus adapted to' operate in accordance .with

the process of the present invention and includ-A,

ing the novel features hereinafter described and claimed.

through pipe 2 and is forced byfeed pump 4 through pipes 6 and 8 to the'upper part of: a tower'10 which functions as a heat exchanger, a bubble tower and a dephlegmator: The pipe 8' connects with a series ofc'oils or heat exchangers 12 positioned above and between the various trays 14 in the column 10 as'described' indetail in the pending applicationreferredto. The oil pre-' heated'in the exchangers 12-discharges* onto'the As illustrated'in the drawing.-raw charging stock, preferably gas-oil first enters the system The dephlegmating tower 10 is preferably set on ormade integral with aicra'cking; chamber 16, in which a frustro-Iconica1'plate18'serves as a separating partition between the two chambers.-' The plate 18 has a central apert ure 20 through which reflux condensate and charging stock discharge from the tower 10 into the chamber below.

i The cracking chamber 16 is preferably divided by a diaphragm 22 into an upper cracking chamber proper and a-lower n'lixing chamber 24 Con: necting with the mixing chamber 24 and mounted onthe diaphragm 22'is a conduit26 which lextends up through the cracking chamber to within a shortdistance of the aperture'20 in the plate 18. Conduit 26 preferably carries a funnel shaped mouth 28 at its upper end for receiving andcharging stock discharging through'the opening 20; Thisconstr'uction'of the conduit 26 and mixing chamber prevents the directmixing of the charging stock and'reflux condensate with the oil'underg'oing cracking'in thecrackirig chamber. Material which has u the cracking chamber may end of this chamberinto ndergon'e cracking in pass fromthe lower the mixing chamber 24 by the pipes 30 where it mixes with thecharging stock andreflux condensate from the tower 10. This mixture, which may have any desired proportion'of the various constituents, is with-- drawn from the mixing chamber by valved conduit 32- and; pump 34 and forced under considerable pressure through pipe 36 to the tubular heating furnace 38 where a suitablecracking temperature. The highly the oil is raised to heated oil is conducted from'th heating furnace arating chamber 42 where y valved conduit40 to the upper end of asepvapors are permitted to separate from unvaporized oil.

The'separator 42 preferably comprises ameans such as the funnel-like partitionconduitne for delivering the unvaporize'd oil, entering. the :top' of the chamber, to the bottom thereof so that the oil leaving, the separator near the top by the conduit- 46 must first go to the bottom of the chamber and rise around theconduit-44, thus leaving any carbon or sludge constituent intherbottom of lthe chamber. The con separator directly with the in which the oil gradually duit 46'connects'the cracking chamber16 works its .Way downward, and into the mixing chamber 24' or as explained later may be drawn directlyinto a concentrator..52 for treatment Vapors "from sepa'-'- rator, 42 pass by conduit; 48 gintow the; cracking chamber and are distribute d into the oil therein which will occur beyond this point or in'the heater 38.

In the construction shown the residuum formed in the various chani'bersis treated in the concentrator 52. For this purpose valved branch pipes 54 and 56 connect the separator 42with-a main discharge line 58 leading to the concentrator 52. Similarly a valved pipe 60 connects the lower portion of the mixing chamber 24 with the pipe 58 and a valved pipe 62 connects. the lower part of the cracking chamber proper with the pipe 58.

The concentrator is preferably. divided by an inverted funnel-like partition ,64 into. a lower vaporizing chamber 66 and an upper dephlegmating and condensing chamber 68, and is preferably positioned with. respect to the separating and cracking chambers so that the residuum will flow by gravity into, and .fill theipart 66 to about the proportion shown in the drawing. The level of the liquid in the three chambers (42, 16 and 52) should be maintained substantially as shown, by proper regulation of the oil fed to and withdrawn from the system.

The residuum introduced into the concentrator is maintained under the same. pressure as is maintained on the oil in the cracking chamber, which may range from atmospheric to several hundred pounds per square inch; ordinarily between 100 and 300 pounds. Inthe vaporizing chamber 66 the vaporization of the more volatile constituents including the gas oil is efiected by introducing av gas through the distributor '70 mounted in the lower part of the chamber 66. The gas leaving the distributor passes upward around the bafiles '72, carrying with it vapors of the residuum and enters the dephlegmating'and condensing chamber 68 through the partition 64. Inthis chamber ithegas and vapor pass countercurrent. to a flow of reflux condensate and finally contact the water-cooled condenser 74 in the upper, part. of. the chamber, which condenses out the lower boiling vapors. The condensate thus formed passesby its own pressure head through the liquid sealed conduit 75 directly into the conduit'26 within the cracking chamber then into mixing chamber 24 where it mingles with the oil therein. The non-condensed gas leaves the concentrator by valved conduit 76 and is recirculated through the system by the pump 78 and pipe. 80

which connects with the distributor in. p The conduit 80 is formed into a coil in heat interchanger 82 which receives the hot residuum discharged from the concentrator by the valved pipe 84, thereby providing a means for extracting the heat from the residuum before its final discharge from the system. The cooled residuum stripped of its lighter fractions is discharged from the interchanger 82 by the valved conduit 86 to be used as fuel oil. The gas to be used in the circuitincluding theconcentrator 52 may be intro duced through valved pipe 88 from any suitable source ordinarily it is taken from the noncondensed gases leaving the final condenser of the cracking system. Due to the absorption of the gas in the cooler oil in chamber 68, it may be necessary from time to time to introduce makeup gas through the pipe 88.

Connecting with the oil inlet pipe 8 is a valved pipe 90 through which charging stock may be admitte dl directly to the conduit 26,with out passing it through the dephlegrnator -coils. Bymanual or automatic adjustment of the valves in conduits Sand 90 the temperature in the dephlegmator 10 may be regulated in accordance with the boiling point desired.- for the vapor leaving the dephlegrnator. The vapors not condensed in the tower 10 pass. bylvalved vapor line 92 to a watercooled coridenser 94 from which the condensate and non-condensed gases pass by pipe 96 to suitable trapsand containers (not shown) all of whicharecommon in the art.

In operating the apparatus described, in accordance with the presentinvention the oil residue either from the separator 42; the mixing chamber 24, the cracking chamber proper or all or them is conveyed by conduit 58 into the concentrator 52 whereit is maintained under the pressure existing in the chambers mentioned. Gas is introduced through the pipe 88 and forced through the pipe 80, distributor '70 and upward through the body of residuum as it flows slowly down over the baflles in the chamber 66.; While the physical pressure in chambers 16 and ,66 is substantially the same the presence of the gas in the latter has the effect of reducing the pressure on the residuum by producing therein a partial pressure of the vapors of the residuum and thereby causes the vaporization of the lighter fractions thereof. In this operation the gas may be suppliedata high velocity and in large quantities to sweep out the lighter ends ofsaidresiduum or it maybe used in smaller amount and, at a slower velocity but heated to a higher-temperature for carrying out the distillation With either procedure the gas is constantly circulated in the system so that none of the vaporizedoil is taken therefrom, The vapors carried by the gasfrom chamber 66, are condensed in chamber 68:and returned to the mixing chamber 24 while the gas is constantly recirculated through. the residuum by pump '78 as referred to above.

An important feature of the present invention the prevention of the deposition of carbonin the various chambers and conduits by constantly (eitherintermittently or continuously) circulatingalarge amount of oil through the separator, cracking chamber, concentrator and heater and constantly removing any 1 carbon and sludge formed in these chambers with the fueloildis; charged from the vaporizing chamber 66 of the concentrator..

In order to prevent the .building up of apres: sure inlthe concentrator greater than that in the other. chambers andthus. stop the flow of residu-- um therefrom I have provided a pressure equalizing line 98 between the concentrator 52 andthe tower 10. A check valvelOO is providedinthis line to prevent flow from the'tower to the concentrator but allow how in the oppositedirection. Ordinarily the pressure in'the concentrator is kept substantially the same asthat in the chamber 16 bythe proper regulation of the valve in pipe 76, the suction and force of pump -78'and the amount of gas introduced. through the pipe 88, but in case of a suddenincrease in'pressurel in the concentrator ,the line 98 will actasa reliefw hr. qllgllliate i. enhle matorl. crackingchamber, and separator are heat-insulated as shown by the legends in the drawing. The conduits carrying hot oil, etc., are also preferably heat-insulated but for simplicity such showing is omitted.

I claim:

1. The process of cracking petroleum oils, which comprises passing oil from a hot oil chamber through a heating zone and then into an enlarged reaction chamber, maintaining a superatmospheric pressure on the oil undergoing cracking in said reaction chamber, passing vapors from said reaction chamber into a reflux tower in heat exchange with fresh charging stock for the process, passing fresh charging stock and re flux condensate from said tower into said hot oil chamber, withdrawing residuum from said reaction chamber into, a concentrator, maintaining the Withdrawn residuum under substantially the same pressure as that in said reaction chamber, passing a preheated gas through said withdrawn residuum to efiect vaporization of substantial portions thereof by the partial pressure effect of said gas, condensing the resulting vapors, and passing the condensate produced therefrom into said hot oil chamber. v

2. In the process of cracking oils under superatmospheric pressure in which the oil is passed through a heating zone and into a cracking chamber, the improvement which comprises withdraw- 40 ing conditions and while maintained under substantially the same pressure as the pressure mainproduce therefrom a distillate suitable for recracking, and adding the said distillate produced from said residuum to the oil to be passed through 50 the said heating zone.

3. The process of cracking petroleum oils, which comprises passing oil from a hot oil supwith said residuum,

ply chamber through a heating zone in which the oil is heated to a cracking temperature and then into anenlarged chamber, maintaining a superatmospheric pressure on the oil in said zone and chamber, maintaining a pressure in said supply chamber substantially equal to that maintained in said enlarged chamber, passing vapors from said enlarged chamber and subjecting them to fractional condensation, withdrawing residuum from said enlarged chamber into a concentrator, maintaining the withdrawn residuum in said concentrator under substantially the same pressure as that maintained in said enlarged chamber, passing a gas in intimate contact with the residuum in said concentrator to thereby effect vaporization of substantial portions thereof by thepar- ,tial pressure efiect of said gas, condensing the higher boiling point portions of the resulting vapors suitable as cracking stock, and passing the resulting condensate by gravity into said supply chamber.

4. In the process of cracking oils under superatmospheric pressure in which the oil is passed through a heating zone and into a cracking chamber, the improvement which comprises withdrawing vapors fromsaid chamber for condensation and separately withdrawing residuum from said chamber into a concentrating still, effecting distillation of substantial portions of said withdrawn residuum in said still without further subjecting the residuum maintained under substantially the same pressure as the pressure maintained on the oil in said chamber, subjecting the vapors evolved from said residuum to reflux condensing conditions in a reflux condensation zone while under said pressure to produce therefrom a distillate suitable for recracking, efiecting the distillation of said withdrawn residuum in said still by passing a gas in a closed cycle through the residuum in said concentrating still and through the reflux condensation zone,

duced from residuum to the oil said to be passed through said heating zone.

5. The process defined by claim 4 in which unvaporized oil residue is withdrawn from said concentrating still, and preheating the gas introduced into said concentrating still by passing it in indirect heat exchange with said withdrawn unvaporized oil residue.

' DAVID G. BRANDT.

to cracking conditions and while

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