US1892437A - Process and apparatus for treating hydrocarbon oil - Google Patents

Description

Deu 27, 1932. J. c. MORRELL ET AL. 1,892,437

u PROCESS AND APPARATUS FOR TREATING HYDRVCCA'RBVON OIL Filed Feb, 6, 1925 i marily consists Patented Dec. 27, 19.3.2 i

UNITED sTATss PATENT ovvio JACQUE C. MORRELL AND JOSEPH G. ALTHER, OF CHICAGO, ILLINOIS, ASSIGNORS TO UNIVERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS AND APPARATUS FOR TREATING HYDROCAARCBON' OIL Application led February 6, 1925. Serial No. 7,214.

This invention relates to a process of hy drocarbon oil conversion and refers more particularly to the production of low boiling point fractions fromhigher boiling point oils, which low boiling point fractions are suitable for commercial use. y

lDuring the past few years, countless attempts have been made by oil refiners to produce end point gasoline as a direct roduct of a crackino` process. Various of t ese attempts haveqbecn more or less sucessful, but not practical to any marked degree, owing to the instability of the final product, which would develop color and odor on standing. It is the specific embodiment of the present invention to produce as a direct product end point gasoline conforming to all the specitications for commercial gasoline as to boiling point range, including end point.

Briefly describingour invention, it riin removing the hydrocar on vopors discharging from the top of the dephlegmator of an oil cracking process or from a plurality of dephlegmators connected into intercommunicating units or in the form of a battery. These vapors, either under the same pressure. as is maintained in the dephlegrnator or dephlegmators or under a substantially reduced pressure down to say atmospheric, are subjected to mixture with steam in a separate fractionating column, said steam and vapors coming1ing physical ly with each other to form a steam hydrocarbon vapor mixture in .this fractionating tower. The steam is preferably introduced for the purpose of maintaining the vapors in a vaporous state and preventing premature condensation lof the major portion of the product at a given temperature, and also to permit these hydrocarbon vapors to con dense simultanenously with the condensation of the steam, that is, the steam being mixed physically with the vapors in the form of a mixture, and condensing the mixture simultaneously, will cause eadh to be condensed in the physical-presence of and contact with the other to secure the utmost stability in the final or hydrocarbon liquid product, per se, and when subjected to a subsequent treatment. Separation of the hydrocarbon liquid and water may take place beyond the condenser, and the fact is to be noted that the Water is darker in color and contains a certain amount of the impurities normally present in pressure distillate `which has been condensed without admixture with steam.

As pointed out above, the vapors from the dephlegmator or dephlegmators mav have their pressure reduced in their passage to the fractionating column, and said physical cominglmg of steam and vapors in the fractlonating column may take place at a presf sure around atmospheric or slightly above.

The various advantages, objects and utility of the present invention may be apparent from the following detailed description, but it may be well to here point out that the inventlon possesses a very great economical feature over present processes which consist in withdrawing the vapors from a number of dephlegmators forming part of a battery of interconnected oil cracking units and condensing said vapors and later subjecting the liquid distillate to redistillation. According to our invention we propose to subject these vapors without substantial condensation to fractionation in the presence of. steam. The basic novelty of the present invention, however, it is to be completely understood, is not necessarily confined to treating lthe vapors from a ,plurality of dephlegmators, but it is to be understood that the novelty resides in the introduction of steam into a zone in which the hydrocarbon vapors from a dephlegmator are introduced 7without pre-- viously undergoing any substantial condensation. i

In the drawing, Fig. l is a diagrammatic side elevational view of an apparatus for carrying out our invention, 23 is a top plan diagrammatic layout illustrating the incorporation of the idea of a single fracn tionating zone serving a number of indepenr'lent dephlegmators. y

In the drawing, l designates a side furnace provided with the combos c ber 2 heated by means of the burners ases of combustion passing through the ilues 4 into the tube chamber 5, the spent gases -being exhausted through the stack 6. 100

The' combustion chamber 2 and tube chamber 5 are separated by means of the bridge,

Wall 7. In the tube chamber is positioned a continuous coil of connected tubing 8, being supplied With oil through the connecting feed line 9, having communication with the raw oil feed line l0, in which latter is interposed the valve 11. The raw oil, instead of being fed directly to the heating coil 8 may be discharged into the upper portion of the dephlegmator 12 through the line 13, in which latter is interposed a valve 14.

It is to be understood also that the feed of raw oil to the system may be split, part of same being fed directly to the dephlegmator and another part being fed directly to the heating coil.

perature, for instance, 750 to 950 F., more or less, and is -discharged into the transfer line 15, in which is interposed a valve 16 discharging into the top of a vertical reaction chamber 17 supported on the supports 18. T his vertical reaction chamber may take the form of a vertically elongated drum or shell, having upper and lower manhole plates 19 for the purpose of cleaning. The lighter fractions of the heated oil being discharged into the reaction chamber 17 through the transfer line 15 will vaporize and will discharge through the vapor outlet 20, in which is interposed the valve 21, discharging into the lower portion of the vertical dephlegmator 12, which is provided with the perforated pans 22. It is to be understood, of course, that the pans 2 2 are merely shown -diagrammatically and that any form of plate, pan or packing to retard the upward flow of vapors and to give contact between the vapor and liquid as is usually employed in this art today would be suitable.

The vapors in their obstructed travel upwardly through the dephlegmator 12 are subjected to physical contact with the raw oil where such has beenintroduced, thus condensing the heavier fractions of said vapors, said condensate being returned by means of the reflux return line 23, in which is interposed valve 24. This reiux may be entirely withdrawn from the system and discharged to storage, or it may be returned either under a hydrostatic head pressure or under a forced or applied pressure by means of the pump 25 to the combined feed line 9. A pressure gauge 26 is provided on the dephlegmator 12.

Describing particularly some of the fea "i tures of this invention, the vapors which do not condense in the dephlegmator 12 discharge from the to of said dephlegmator into the vapor line 2 in which is interposed the valves 28, which preferably take the form of pressure reducing valves, the discharge end of said vapor line 27 discharging into the lowerportion of a vertical fractionating column 29. This vertical fractionating col- The oil passing through thev heating coil is heated to a conversion tein-A umn 29 maybe provided with the perforated haseplate 3 ).and any suitable form of packing 31 .may'be employed as is usually used in fractionating columns in this art. As pointed out, directly adjacent the' point of introduction of the vapors to the fractionating column 29 is a steam inlet pipe 32, in which is interposed a valve 33, said steam inlet be- `ing connected with any suitable source of steam supply, either of the saturated or superheated type.

'Further describing the tower 29, it may be any suitable type, such as the packed, pan, plate, or bubble type. The steam and vapors physically co-mingle with each other in the lower portion of the fractionating tower 29 assing upwardly, their flow being retar ed by means of the elements 31 and discharging at the top thereof into the line 34, in which is interposed valve 35 communieating with the condenser coil 36 in condenser box 37, the condensing coil 36 communicating by means of the line 38, in which is interposed the valve 39 with the combined receiver. and separator 40. This combined receiver and separator 40 may be provided with the usual sight-glass 41, uncondensible gas outlet 42 controlled by valve 43, and liquid outlet 44 controlled by valve 45. The liquid discharge 44 is the discharge for the oil distillate, and a second discharge 46 controlled by valve 47 is provided for the purpose of withdrawing the water. The oil withdrawn through the pipe 44 may be withdrawn to storage through the pipe 48, the valve 49 being opened, or it may be returned by means of pump 50 to the line 51, the valve 52 being opened, said line 51 discharging into the upper portion of the fractionating column 29. By returning the portions of the pressure distillate to the upper portion of the fractionating tower 29, a uniform or` regulated temperature `may be maintained therein, and the subjection of the vapors coursing upwardl 'through said fractionating tower 29 coming in direct contact with the cooled distillate may condense the heavier,

fractions of said vapors.

Theliquid condensate from said fractionating tower 29 may discharge through the line 53, in which is interposed valve 54, communicatin with the coolin coil 55 in the condenser 0X 37, after which it may discharge through the line 56; in which is interposed valve 57 into what may be termed the pressure distillate bottoms receiver and separator 58. This .receiver 58 maybe provided with the discharge drain 59 controlled by valve 60, for the purpose of removing the water which stratiies in said receiver. The liquid o il in saidreceiver may be withdrawn through the line 61 controlled by valve 62 and sent to storage for further refining, or it may be withdrawn by means of the pump 63 in` terposed in the line 64 and returned through dephlegmator 12 a lighter gravity oil for the purpose described.

Referring to Fig. 2, we have illustrated the use of our invention in connection with a number of oil cracking units interconnected into the same battery. A number of alternately connected reaction chambers may be used with diverting lines 15 branching out from the transfer line 15 with suitable valves interposed in said lines 15', the purpose being to operate the process continuously over long periods of time and allow for freely cutting in anew tank 17 while s1- Y multaneously cutting out another one. It 25 may be here pointed out that Fig. 2 is not an identical plan layout of the side elevation shown in Fig. 1. The vapors from either of the chambers 17 discharge into either of the vapor lines 20 controlled by the valves 21 into thedephlegmator 12. lt is to be understood that although we haveillustrated two units in this particular battery, the invention is adapted to be utilized in connection with units of say five each in the battery, with,`

of course, the understanding that any number may be utilized. rl`he vapors discharging from the top of the dephlegmators 12 through thevapor lines 27 and past the pressure reducing valves 28, pass into a single fractionating column 29 common to a plurality of dephlegmators.

Describing now the operation of our invention, the raw charging stock may be introduced either directly into the heating coils v or into lthe upper part of the dephlegmator 12, and said oil heated in its passage through the heating coils to a cracking or'conversion temperature,'for instance, between 750 and 950 F., said heated oil being discharged into the reaction chamber 17, where the lighter fractions thereof separate in the form of vapors and where the unvaporized residue builds up in a substantial body composed of ,unvaporized ,liquid and precipitated free coke. The unvaporized liquid residue may be withdrawn from time to time through the residue draw-oit line controlled by valve 69, a plurality of these lines being provided at various heights on the reaction chamber for the purpose of providing discharge for the'liquid at various heights when thel free coke has built up inside the chamber.

The vapors discharging through the vapor line 2()l are dephlegmated in the dephlegmator 12, the reflux being returned to be reheated,

lvapor line 27 p steam, and this mixture courses upwardly This pressure is preferably reduced by means of the reducing valves 28 materially below the pressure maintained on the balance of the system, preferably around atmospheric. It

Amay, of course, be slightly above. The vapors discharging through the bottom of the ysically co-mingle with the through the fractionating tower 29 countercurrent to the iiovv of liquid distillatewhere same is returned through the line 51.

One of the primary purposes for the introduction and physical mixing of the steam and vapors in this fractionating column 29 is to prevent any substantial condensation therein, although in order to most eifectually fractionate the vapors therein, some condensation must take place, and therefore portions of the distillate may be returned through the line 51 to provide reflux and at the same time act as a cooling medium. It is understood, of course, that the reaction chamber 17, dephlegmater 12 and fractionating column 29' may be insulated if desired. V

The reduction in pressure between the dephlegmator 12 and fractionating column.

the system is controlled by a suitable valve on the final receiver and separator 40, which also acts as a gas outlet. It is a known fact in the fractionation of vapors in a cracking system that it is easier to secure' a clean separation of lighter fractions such as gasoline at low pressures than it is at high pressures.

The steam assists in lowering the temperature necessary to keep the hydrocarbons in a vapor state and prevents premature condensation. The primary and major purpose for the introduction of steam is to produce a gasoline-like product which per se is more stable than a product the vapors of which have not been mixed with steam, and also, such' a product will be more amenable to treatment to produce a stable, marketable product. This result is brought about in a great measure by the hysical co-mingling atrd condensation of hydrocarbon vapors and s am.

It has been the experience of applicants covering a period of several years that in order to treat cracked gasoline-like products without redistillation by chemical means and especially by. what is referred to as the sulphuric acid method of treatment, these cracked gasoline-like products for the most part must bc distilled in the presence of steam. Further, when these cracked gasoline-like products were fractionated from a crude distillate, using fire alone, and then subJected to chemical treatment, in spite of the use of every precaution, the product is almost invariably unstable with respect to color and odor. On the other hand, when these cracked distillates are redistilled and condensed in the presence of steam, the resultant product usuall)7 remains waterwhite, stable, and is perectly marketable.

At the lower pressure employed in the tractionating tower 29, some heavy ends will condense. out. the process being practically one of fractional condensation, along with some Condensed water, both liquids being withdrawn through the cooler 55 intoK the receiver 58, where the water is separated and withdrawn through the line 59.

It must be here understood that the fol-V lowing method of further refining the liquid oil product collected in the receiver 40 has been found preferable.

This liquid oil product may be iirst subjected to a water wash followed by treatment with a solution of litharge in caustic soda, referred to as plumbite solution, and then treated with sulphur-ic acid of concentration varying from 85% up to 95%, the latter reter-red to as concentrated sulphuric acid, usually known as 66 Baum acid. The acid sludge is then drawn off after a period of agitation, -the vgasoline is then thoroughly water Washed. neutralized with caustc soda, and finally, it has been advisable to treat with a small amount of fullers earth or like absorbent. i LThe gasoline mav beA filtered through acolumn of this earth, or a simple means of treatment is to agitate with the. earth. previously allowing practically all of the water to settle out. Any earth which remains suspended is washed out of the gaso: line by agitating with water. In some cases, it has been advisable to substitute a plumbite solution for the caustic soda in the above treatment. This plumbite solution consists of a solution of litharge in caustic soda.

It may be advisable under certain circum'- stances to treat w'th absorbente alone, this being perfectly feasible with the gasoline product obtained by this process.

Finally. it is to be pointed out that although some commercial systems have attempted to produce end point gasoline from a cracking system, for the most part they have been unsuccessful in later treating this gasoline into a commercial, waterwhite and stable product.

lVe are well aware that heretofore, various inventions have been perfected relating to the redistillation of liquid distillate in the presence of steam, and we differentiate therefrom in that we subject the vapors Without any intended or substantial condensation to actual physical contact with said steam, preferably 'under a reduced pressure. It is to be noted that our invention is carried out as part of a continuous process and without any material change in present equipment.

By the term end point gasoline, we mean gasoline having an end point of or below 437 F. l

We claim as our invention:

1. A process ot'hydrocarbon oil conversion, consisting in subjecting the oil to conditions of conversion temperature and superatmospheric pressure to cause substantial vaporization, subjecting the vapors to dephlegmation while maintained under superatmosphcric pressure, removing the uncondensed vapors and physically commingling same with steam to cause an intimate mixture ot the steam and vapors, causing said mixture to have. an obstructed upward passage through a fractionating zone, in then condensing the mixture and separating the water and oil after condensation, returning portions of the condensed vapors free `trom water to the fractionating zone to condense the heavy ends of the mixture, and returning thev resulting condensate under an applied pressure to the zone of dephlegmation.

2. A process of hydrocarbon oil conversion, consisting in subjecting the oil to conditions of conversion temperature and superatmosphcric pressure to cause substantial vaporization, subjecting the vapors to dephlegmation while maintained under superatmospheric pressure, removing thev uncondensed vapors and physically commingling same with steam to cause an intimate mixture of the steam and vapors, causing said mixture to have an obstructed upward passage through a fractionating zone, in then condensing. the mixture and separating the water and oil after condensation, withdrawing portions ot the condensed vapors free from water under an applied pressure and discharging same into the Zone of dephlegmation.

3. A process of hydrocarbon oil conversion, consisting in subjecting the oil to conditions of conversion temperature and superatmosphet'ic .pressure in a battery of interconnected oil cracking units to'cause substantial vaporization, dephlegmating the vapors under superatmospheric pressure, passing the uncondensed dephlegmated vapors to a single fractionating zone prior to any substantial condensation of the vapors, introducing steam to said fractionating zone in physical Contact with the vapors, obstructing the uping medium for the vapors. 4. In an apparatus for treating oil, con? sisting. in an elongated passageway, mounted in a ,heatinv means an enlar ed reactionA .l chamber communicating therewith Where `substantial. separation of vapors takes place, a dephlegmator communicating with the vapor space of said reaction chamber, a

ractionating means, means connecting` the vapor space of said dephleginator witlisaid fractionating means, means in said connectF` ing means for controlling the vaporjpresj .su-re, means for introducing steam tojsa'id fractionating means to be mixed with the vapors therein,'obstructing means in said* -Vfraotionating means retardiiig the upwardv condensing -the-uncondensed mixture and means for returning portions of 'the condensed oil reefrc-m yivaterto the fractionating and dephlegmating means. j l,

5. In apparatus for hydrocarbon oil con' `version, the-combinationwith a battery of oil .cracking units comprising a pluraiity of. heatin'gand conversion means, each of the latter having "a vapor space, a dephlegmatoi communicating with each vapor space, of a.

single fractionatingin'eans connected with" the vapor space of the dephlegmators, means in the connections between the plurality of dephlegmators and single ractionating means for regulating thel pressure. on the system, means for introducing steam to said single ractionating means to-mingle in.

physical Contact with the vapors, condensing means and means for forcing, under applied pressure, the return of portions of the oil condensate free from water to each of the dephlegmators or-single fractionating means.

6. A process for treating cracked hydrocarbon oil vapors comprising subjecting such vapors to dephlegfmation in a zone maintained under a superatmospheric pressure, passing the uncondensed dephlegmated vapors to a ractionatingcolumn, preventing premature condensation of the major portion of the dephlegniated vapors in said fractionating column by introducing steam :vapors to de'phlegination' in a zone maintained' under a superatmospherie pressure, passing' the uncondensed dephlegmated vapors to a ractionating column, preventing vprem attire condensation of the major portion of the dep'hleginatedvaporsin said fractions at: ng column by introducingfsteam to physi.

cally. commingle Withv the vapors insaid fraic- -tionating column, causing the commingled steam and vapors to have an obstructed pas-l sage through said column, maintainiii the. coinmingled steam and vapors in said co .umn

under a substantially atmospheric pressure,

subjecting the 4coininingled steam and'vapors subsequent toztheir passage Y.froi'iisaiol column to condensation, and thereafter e'decting a soA separation of the resultant'water and distil-. i late, and returning portions of the resultant j distillate to the zone of dephlegmation'main j j, @tained under superatmospheric pressure. iiow of said vapor-steam mixture, means for 8j. In the art of hydrocarbon oil conver sion, the improvedinethod `of treating the cracked vapors which comprises subjecting the vapors to initial deplilegination', subject, .ing thedephlegmated vapors to *fractionsfractionation., condensing :the fractionated vapors-and remaining steam,y separating the resultant pressure distillate from the Water,

and returning portions of the .pressure dis-'pj tillate to the initial dephlegination step as a cooling mediuim JCQUE C'. 'MQRRELL 'JOSEPH'..GL 'LTHER to physically commingle with thev vapors in v said Jractionatng column, causing the Vlcommingled steam and vapors to have an obstructed passage through said column, maintaining the commingled steam and vapors iii said column under a substantially atmospheric pressure, subjecting the commingled steam and vapors subsequent to theiripassage from said column to condensation, and

thereafter' effecting a separation of the re,

sultant Water-and distillate.4

7'. A processfor treating cracked hydrocarbon oil vapors comprising subjecting such

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