US2366900A - Separation process - Google Patents

Description

Jan. 9, 1945. H. M. wElR SEPARATION PROCESS Filed July 11, 1941 Uma. NIN

Patented Jan. v`1945 2,366,900 SEPARATION rnocnss Horace M. Weir, Wynnewood, lPa., assgnor 'to The United Gas Improvement (Company, a corporation of Pennsylvania,

Application July 11, 1941, Serial No. 401,966

v(Cl. 252-346) 15 Claims.

For purposes of convenience in description, that portion of the distillate boiling up to approximately 200 C. (392 F.) at atmospheric pressure,

will be designated light oil and that portion oi the distillate boiling above approximately 200 C. at atmospheric pressure will be designated dead oil. These may be separated fromeach other gas and oil gas wherein a petroleum oil such as crude oil or a fraction or fractions thereof, for example, gas oil, residuum oil, etc., is pyrolytically decomposed. y

In such processes the gas leaving the gas-making apparatus is usually brought into contact with water such as in the wash box, and as a result the tar which separates from the gas is usually recovered in the form of an emulsion with water. The tar emulsion in extreme cases, may contain as high as 95% water or even higher. In some cases,` the tar emulsion may be in the form of a pasty solid of very high viscosity. As a rule, the tar emulsion Will contain at least 50% water and in this respect diiers from tars obtained in processes for the production of coal gas or coke oven gas or in many oil cracking processes for the production of motor fuel, for in the latter processes the tar as recovered is not in an emulsion form. Therefore, the term tar emulsion'or petroleum tar emulsion as used hereinafter and in the claims refer to emulsions of tar and water produced in the manner described, namely during the manufacture of combustible gas by processes involving the pyrolytic decompositionof Detroleum oil.

The recovered mixture of tar and water from gas-making operations involving the decomposition of petroleum oil is usually rst collected in a settling tank for the separation of as much water as possible by layer formation and decan tation.

In accordance with prior art practice the relatively stable tar emulsion which remains after separation of the water layer has usually been treated according to some method of dehydration,

such as centrifuging or distillation.

Centrifugal methods of treating tar emulsions, however, separate only the tar and the water of the emulsion and do not separate lighter tar con-y stituents from the heavier. Furthermore,A the presence of free carbon in the emulsion may give rise to operating diiliculties.

'Ihe separation of the tar emulsion by ordinary distillation methods results in fractions which comprise (1) water, (2) a distillate. from the tar comprising light oil and dead oil, and (3) resid ual tar.

by distillation.

The light oil fraction. contains, among other things, valuable saturated and unsaturated aromatic hydrocarbonsY such as benzene, toluene, xylene, styrene, methyl styrene, indene, etc.

The dead oil fraction contains naphthalene, methyl and other substituted naphthalenes, and may contain anthracene, methyl anthracene, as

well as numerous other hydrocarbons for the most part as yet unidentified.

The residual tar contains free carbon, pitch and other bitumens and'usually contains constituents which are polymerizable.

The residual tar has a number of uses. For example, it may be used as a road tar or as a heavy liquid fuel. For both purposes, the viscosity of the residual tar is of importance, among other things, because of its eirect upon the ease of handling.

Due to the fact that the tar is subjected to elevated temperatures for considerable lengths of time such as of the order of 10 to 16 hours in ordinary distillation procedures of the prior art for breaking emulsions and for the separation of light oil and dead oil as distillate, substantial polymerization is caused to take place. Such polymerization tends to reduce the quantity of distillate on the one hand and to increase the viscosity of the residual tar on the other, both of which are undesirable.

In copending application Serial Number 342,- 735, iiled June 27, 41940 by Edwin L. Hall and Howard R. Batchelder, there is described and claimed a process -for breaking tar emulsions with the recovery of light oil and substantial quantities of dead oil containing considerable quantities of constituents in readily heat polymeriz'able state. In said process a tar emulsion is rapidly heated to an appropriate temperature capable of volatilizing considerable dead oil and then discharged into a separation zone which may be maintained at any desired suitable pressure, such as atmospheric or subatmospheric. Thus a relatively large percentage of extremely heat sensitive unsaturated resin forming material is recovered in the dead oil fraction which is not the case in prior art practice for in the latter practice these materials are polymerized and left behind the residual tar.

This invention is a modification of the invenytion described and claimed in said copending application` and is'directed to improvements in the separation of l`more volatile constituents from less volatile constituents.

The various features of the-invention will become more apparent to persons skilled in the art as the description proceeds and upon reference to the drawingfixiwhich: Y

The figure is a now sheet diagrammatically illustrating one form of the invention.v i'

Referring now more particularly to the figure, AIll is a Dreheater for petroleum tar'emulsion which enters through line Il and leavesthrough line I2.

Line I2 leads to vaporizer I3 being connected to inlet I 4 which as illustrated comprises a header which communicates with the lower'ends of.a plurality of up-pass tubes I5.

Up-pass tubes I 5, at their upper ends communicate with the chamber I6.

Down-pass tubes I1 are connected to chamber I6 at their `upper ends and with .chamber '20 at their lower ends.

' Theoperationoftheapparatmsofardescribed Emulsion yto be separated fed through feed 2 line 55 ofthe line II andinto preheater Il in which any desired quantity of preheat may be Aadded to the emulsion to be separated.

' Preheated emulsion :Hows through line I2 into vaporizer I3 in which the temperature israised Y suiiiciently to elect considerable vaporization Shell 2I of vaporizer I3 surrounds the up-pass and of any desired eiliciency. However, I gener- Y prefer to employ phase contacting means of a relatively open 4character and having hardly more than a few theoretically'perfect plates.

It is to be understood, however, that phase contacting means may be'omitted or other means for the separation of highliling constituents may be substituted therefor, such as means for the separation of entrained liquid particles, the purpose beingy toprevent or reduce the overhead travel of taror otherhighcolored liquid particles.

Vapor outlet 3l of chamber'25 is connected to inlet 32 of condenser 33.-

Condenser33 is conveniently cooledin a manner to generate steam for use in a second separating stage, if such is provided or for other purposes, although any type of condenser may be eml- As illustrated, condenser 33 has aninlet 34 for water and an outlet 35 for generatedlstearrir it being understood that condenser 33 is of the in direct heat exchange type.

condensate outlet 3646? condenser 33 is con-- nected to inlet l3l of coolerllll.

outlet 4| of cooler 4021sconnected to a del A canter 42. Decanter 42 has an outlet 43 forthe water layer and anbutlet 44 for the hydrocarbon:

layer. t Y

Outlet 44,01 decanter 42 is connected through line 45 with a tank 46 -from which a line 41 leads back to the upper portion of separating cham- 70 ber 25. i

VSeparating chamber 25 has a liquid outlet 5I which is connected by line 5ll and pump 52 to line Y 53which in turn is connected to line II through valve'54. Feed line i-iorpetroleum. sion is also connected to line II.A

' Vtakes place in separating chamber 25 which if provided "with phase contacting means 30, may

also be provided with down flowing reflux provided through line 41 from hydrocarbon collecting chamber 45, by pump 4I.

When the separation of the Ypetroleum tar emulsion into its constituents takes place in a single stage however, the provision.. of hydrocarbon reilux for countercrrent contact l.with ascending vapors in the upper portion of chamber 25 may be omitted-and bailies or other phase separating means may be substituted for phase contacting means 3l,Y or v'the upper ,portion of chamberV 25may be relatively empty.

Separated vapors ilow through outlet 3| to condenser 33 wherein as illustrated, the heat re leased upon condensation heats cooling water to such an extent as to generate steam therefrom,

although it is to be understood that this is mereg ly for the conservation of'energy and that any other type of condenser might be substituted.

Depending upon the amount of condensation which takes place in condenser 33, the materials which enter cooler 4l through inlet 31 may be wholly or only partially inthe liquid p hase, the function of cooler 4l being to cool the constituents to 'any desired lower temperature and preferably sufficiently to condense any uncondensed portion.

The condensate flows from cooler 4I) into decanter 42 for separation by layer formation, water beingwithdrawn through line 43 and hydrocarbons through line 45. The reliux liquid when provided inV separating chamber 25 is furnished conveniently from the hydrocarbons which collect in collecting chamber 46.

I ndthat it is especially advantageous from Y the standpoint 'of efficient separation of relatively' volatile from relatively non-volatile constituents zones at a relatively high rate. A very high`efciency of separation is thus obtainable and any tendency for high molecular weight; tarry hydrocarbons andfree carbon to separate and adhere` Vto the walls of the system is very effectively overcome. i

v To eil'ect this purpose any desired portion of the liquid drawn of! from chamber 25'through line 5l may berecirculated through the heating Iand' separating zones through line 53 and valve 54, line 53 connecting to feed line I I, pump 52 being provided to maintain any desired rate of circulation.

Any desired portion of the non-vaporized constituents may be drawn off through valve 56 and line 51, untreated emulsion being fed in through line 55 to compensate therefor.

Any desired proportion of fresh feed stock to recirculated stock may be maintained such as, for example, from 1 to 1 or less to 1 to 50 or more, although I prefer to operate between' l part of fresh feed stock to parts of recycle stock to l part of fresh feed stock to 35 parts of recycle stock.

From the-foregoing it will be seen that a rapid transit of the materials under treatment through the heating zone and into and through the separatingzone is preferred.

As a result of my invention, a highly eective and satisfactory separation is made between residual tar and constituents which it is desired to yremove therefrom and such separation may proceed at a very high rate.

Further more, the materials in process are more eiectively heated and thus more eectively and efficiently separated since Iany tendency for the separation and adherence of highly non-volatile tar constituents to the heat exchange walls of the vaporizer is effectively overcome.

Furthermore, the very rapid rate of ilow of liquid materials through the heater produces a high degree of turbulence and a very efficient heat exchange. Still further, the elimination of any tendency towards stream line flow prevents the overheating of a layer of' material close to the heating 'surfaces with the consequent polyterialcontained therein.

In accordance with my invention, tar emulsions.

may bel dehydrated in a manner (l) such that the yield of deadoil therefrom may be increased at the expense of residual tar Without encountering a corresponding increase in viscosity of the residual tar; or (2) such that for a given yield of dead oil a residual tar of lowervviscosity is obtainable than by conventional methods. Furthermore, it is possible to obtain by my process a higher dead oil yield 'than is possible by conventional methods. Moreover it i5 possible to obtain by my process in the dead oil yield a relatively high percentage of extremely heat sensitive monomeric material which when employing conventional methods is polymerized to extremely non-volatile tar constituents which nd their way into the residual tar instead of into the dead oil.

These highly heat sensitive dead oil constituents are very valuable from the standpoint of resin manufacture Whenseparated in the dead oil fraction but are relatively of very little value when polymerized in the 'separation process to form residual tar.

while processing the bottom or residual material to give the desired residual tar viscosity.

It Will be understood that two factors effect residual tar viscosity, namely (1) the proportion of relatively fluid oils left in the residual tar which may be controlled by the proportion of volatile Vmaterial removed overhead, and (2) the proportion of unsaturated material polymerized t into less volatile more viscous polymers.

Thus in the practice of my invention a tarl emulsion is rapidly heated to an appropriate temperature and then discharged into a separation zone which 'may be maintained at any desired suitable pressure such as atmospheric or below under conditions such that (1) the vaporized portion may berapidly separated and removed, and (2) the unvaporized portion is rapidly recirculated with a portion removed and preferably cooled to below polymerizing temperatures.

By such procedure, highly heat lsensitive Volatilized material in process does not remain at op-A It will be understood that a part of such un\ saturated material may actually be so relatively non-volatile as to nd its way into the residuall tar in any event. v

Since in the practice of my process when operating at temperature sufficiently high to seriously aiect the highly heat sensitive constituents of the dead oil, such constituents are rapidly separated in vaporized form from the relatively non-volatile residual tar constituents, it follows that the residual tar from which a relatively large proportion of highly heat sensitive materials has been separated may be kept in process at elevated temperatures for a considerably longer period of time without undue increase in viscosity, than is possible in conventional methods of tar dehydration. As a result it is possible in my process to continuously recirculate the residual tar through the heating zone for a considerable period of time without too seriously effecting the residual tar viscosity and by virtue of such recirculation a relatively large proportion of the volatile constituents in the tar are aorded an opportunity to'vaporize and to be separated in vaporized form from the residual tar.

In my process, assuming that other things remain unchanged, item (1) preceding may be in.- creased and decreased-by decrease and increase in the temperature to which the materials are subjected in the heating zone. However, consideration should be given to the effect of higher temperaturesupon (2) preceding taken in conjunction with heating time. Since polymerization is a function of both temperature and time the eiect of higher temperatures during shorter heating times may be made the equivalent of the eiect oflower temperatures during longer heating times. I find that a relatively wide range of both temperature and heating time is afforded particularly when operating at atmospheric pressures and below, without losing the advantages of my method over conventional methods of tar dehydration. .Howeven I prefer to maintain the time during' which the highly heat sensitive volatile material is heated while in contact; with the relatively non-volatile constituents at a virtual minimum or at least relatively lowl in order to avoid the polymerization of such highly heatsensitive volatile material into relatively non-volatile residual tar constitutents.

Preferably the highly heat sensitive clead oil constituents are not subjected to temperatures of the order of C. and above for longer than ninety minutes with still shorter periods of heating still more preferable as above indicated.

Preferably also the 'tar residue is not subjected to heating longer than three hours with shorter periods still more preferred. As previously -stated however wide variations may be made :from such preferred periods while still securing advantages ot my invention.

As pointed out previously, the process may be conducted in one or more stages. A twostage process is very convenient since this makes it possible to take overhead at atmospheric or nearV atmospheric pressures the more relatively volatile constituents such as water, benzene, toluene, xylene, styrene, methyl styrene and indene. which may be condensed at normal temperatures and assdaoo j 'a relatively smauproportion of mateneu'boiunz above say 200 C., when at atmospheric pressure.'

The residual tar from this stage may then contain the preponderate part of the dead oil constituents. All or any desired portion of this tar may be passed through line 53, valve 58 and line 59 into se'cond stage vaporizer 6| wherein it is the use oi' considerably reduced pressures for the removal of the less relatively volatile constituents Ysuch as those boiling above 200 C. and up to 350 C. and higher when atratmospheric pressure and Vto also condense these materials at ordinary tmperatures. The use of considerably reduced pressures when removing materials such as benzene might require condenser temperatures sumciently low to solidify a part of the condensate to cause condenser stoppages.

The use of considerably reduced atmospheric .pressures in the separation of highly heal-sensi- 'tive dead oil constituents is preferred since this chamber 62.311 the same manner as nrst stage separating chamber 25 is connected to first stage vaporizer I3. Thus `vaporizer Si and Separating chamber 62 may if desired have substantially the same design and construction as vaporizer I3 and separating chamber 25 respectively and may be connected together in substantially the manner. 1

Vapor outlet 53 of chamber i2 leads to con'- denser i4 which-in turn is connected through line 65 to a condensate receiver 65.

AAs illustrated, a vacuum line il for maintaine ing the desired reduced pressure in separating chamber B2 connected to receiver 6 6. Vacuum line 51 is connected ivo-pump 'i0 which discharges into a decanter 'li for separation of water through outlet 12 from hydrocarbon condensate outlet 13.

L Since the hydrocarbon condensate separated in the 'second stage is of a -density similar to that of water and changes more rapidly with change inA temperature than water, under certain conditions the outlets f or water and hydrocarbon condensate at decanter 'll might be reversed.

Liquid outlet I I at the bottom oi' chamber l2 connects with line 'l5 which leads to pump 16, one outlet of which connecls with line TL', provided with valve 18, which in tln'n conn with line 5S, 111e other outlet of pump 1i connects with line Y18, provided with valve lll, which may lead to storage or to any other suitable point.

-The operationof the process in two stages may be described as follows. l

-Therirststagemayoperateinallrespects similar to that already described with 'the exception that a lesser or the volatile material from thetar is taken overheadin the first stage. For example, the material taken overhead hr the rst stage might he comprised preponderately. o! constituents which boil for the most part below say 200 C., when at atmospheric pressure, with through Vheated preferably under vacuum to an appropriate temperature to volatilize a substantial quantity of the dead'oil constituents `therein. Liquid and vaporized constituents ilow from vaporizer 6l into separator 62 wherein volatlli'zed constituents are separated' from 'non-volatilized constituents and taken overhead to condenser il wherein they are condensed and collected in receiver 56 from whichthey iiow through vacuum line 6l, pump 10 Vinto dccanter ll for the separation' of hydrocarbon condensate from any water which might be present.`

If desired, separating chamberv 82 may be pro-- vided with baiiles o1:A any other means to prevent entrainedfnonfvolatilized tar particles from passing overhead. with Vthe vaporized constituents.

Nonfvaporized liquid flows from separating lchamber 62 through line 15, pump 16, line 'l1 to line 59 back to and throughheater 6I and sepa'- rating chamber'62. Y

The proportion of recirculated stock to incoming tar stock from the iirst stage may be maintained at any desired level, for ex ple the Same as described in connection withethesingle stage.

Likewise, Vinthe iirst stage the proportion may be the same as described/in the single stage operation.

Residual tar isdrawn oif from pump 16 through line 'I9 and may iiow to storage or to any other Ydesired-point.

If desired the partial pressures ofthe vaporized hydrocarbons in'vaporizer 3, separating cham-L ber 25, vaporizer 6l, separating chamber", etc., may be' reducedf'by the addition of suitable gas,

such as stripping steam.v For example strippingr steam may be introduced into vaporizer 6I and means for this purpose is illustrated at 8| which comprisesa steam line leading from' outlet 35 of inlet 82 at the top of thevaporf.

g stage. To reduce the quantity of dead oil separated in the first stage .it is frequently desirable above.

to provide suilicient redux'in the stage and suillcient phase contact in separator 25to scrub out constituents from the vapor which boil above say 200 C. or 210 C., or at any other'V chosen cut point.

The -two stage process with the recycle of tar in one or both stages and particularly in both stages isa highly eilcient method for 'the separation of a petroleum tar emulsion -into its constituents as illustrated by the following example.

A Example -I Petroleum oil enulsion, containing approximately 37 percent water and having a speclilc gravity of approximately 1.02, was dehydrated in a two stage apparatus similar to Ythat described The emulsion was fedtothe ilrst'vaporizer YStill at a rate-of approximately 10 gallons per minute and'heated therein to approximately C. at approximately `atmospheric pressure..

-The heated material was-led from the ilrst stage vaporlzer to ,the ilrst stage separation zone and The time the dead oil constituents were exthe 4vaporized and unvaporized constituents separated therein, at substantially atmospheric pressure, the vaporized material being taken oi overhead, and the unvaporizedv being taken oi from the separating chamber as bottoms.

80 per cent of the water in the emulsion fed to the vaporizer was taken oi overhead from the rst stage, together with a quantity of hydrocarbon material equal to approximately 0.19 pounds per pound of dry tar fed to the vaporizer in the form of emulsion, approximately 94 per cent of this hydrocarbon material was comprised oi' light oil constituents and approximately 6 per cent was comprised of dead oil constituents.

The bottoms from the first separation stage was comprised of the remainder of the water, approximately one-.third of the light oil, the bulk of the dead oil and substantially all of the residual tai` constituents contained in the original emulsion. l y

A portion of these bottoms led oi from the first stage separation chamber was recycled to the first stage vaporizer, at a rate of approximately 250 to 300 gallons per minute.

The remainder of the bottoms from the rst separation stage was fed to the vaporizer of the second stage and heated therein to approximately 145 C.

The heated material was led to the second stage separation zone which together with the second stage vaporizer was maintained at a pressure of approximately 100 mm. Hg. absolute and the vaporized and unvaporized materials were separated therein.

The vaporized material was passed upward through the separation chamber and was taken ci as overhead. The unvaporized material was passed downward and was taken 01T as bottoms.

The overhead material from the second stage separation contained the remaining 20 per cent of the watercontained in the original emulsion together with a quantity of hydrocarbon material equal to approximately 0.36 pound per pound of dry tar in the original emulsion fed to the first stage.

The overhead material from the second stage separation also contained the water supplied to the second stage in the form of stripping steam, which was employed in quantity equal to approximately 0.5 pound per pound of dry tar fed to the rst stage still in emulsion form.

Of the hydrocarbon material taken on overhead from the second stage, approximately 2:7 per cent was comprised of light oil constituents and approximately '73 per cent wasfcomprised .of dead oil constituents, associated with small quantities ofl entrained unvaporized residual tar constituents,

The bottoms from the second stage separation was comprised of dry residual tar, which was divided into two streams.

the second stage vaporizer at a rate of approximately 250 gallons per minute.

Separated dry' residual tar having a viscosity 'of approximately' 4000 S. S. U. at 210 F. was

recovered in quantity equal to approximately 0.4 5 pound per pound of dry tar in the emulsion fed tothe first stage.

Light oil from the two stages totaled approximately 0.27 pound'per pound of dry tar in the emulsion fed to the rst stage.

Dead oil from the two stages totaled approximately 0.28 pound per pound of dry tar in the emulsion fed to the rst stage.

One stream was ledo as product. vThe other stream was recycledto It will be noted that the temperatures employed in the first stage are very low in the bracket of from 100 C. to 350 C. which was given as an l5 example of a range in temperatures'and that the temperatures employed in the second stage are somewhat higher in this bracket.

Itwill be understood that the temperatures l given are purely for example. If sub-atmospheric pressures are employed in the nrst stage, lthe temperature in the rst stage may be below l100 C.

Preferably the temperatures in the'rst stage, when no dead oil constituents or only a relativelysmall proportion of the dead oil constituents are taken ol overhead, do-not exceed approximately 120 C. This is because a large proportion of the dead oil is recycled along with the residual tar in this 'stage and it is of course ydesired to avoid a large ydegree of polymerization' of the highly heat sensitive constituents in the deadoil.

In the second stage which is operated at a higher temperature (and at a lower pressure) the dead oil is-.taken overhead immediately upon vaporization and separation from the residual tar. Thus in this stage recirculation of the residual tar does not increase the quantity of highly heat sensitive dead oil constituents polymerized'into non-volatile constituents but actually/.affords `an e@ opportunity forany non-volatilized dead oil vconstituents to be separated from the residual tar during the recycle thereof. Since the highly heat sensitive dead oil constituents are rapidly separated from`the'residua1 tar in the second stage the residual tar may be i recycled Without danger of reaching an excesl in connection'with the process it is to be understood that thisv is subject to considerable variation and diierent forms of apparatus and design are' within the skill of an experienced engineer.

e. It will also be understood that the process is subject to considerable variation.

More than two stages may be employed if desired and any desired division may be made as to the materials taken off overhead and as bottoms from the various stages.

When employing two or more stage it may be preferred to remove substantially all of the water in the rst stage feeding substantially dry tar to the second stage, on the other hand only a portion of the water vmaybe removed in the rst V for example all of the dead oilvrecovered being'.

taken of: overhead from the second stage.

If only one stage is employed it may be desired V ing preheater llly and the vaporizers I3 and y6| y water content of the emulsion fed to line 55. y

to admit a gaseous stripping agent to vaporizei':r v

I3, and it may be desired to employ ay gaseous v strippingagent in the first stage as well as iny succeeding vstages when more than one'stage is y employed. Ther use of a gaseous stripping agent,

y f such for example as steam, in the single stage or in the rst stage of a plurality of stages is parv f ticularly desirable if the proportion of water in the petroleum tar-water emulsion treated is low.

vIt may-be desirable also to 'vary the quantity of stripping agent supplied to succeeding stages f v in accordance with the water content terial supplied to such stages.

of the ma- Any desired meansfmay-be provided for heatv such as ring by solid or fiuid fuel, though heating by steam may be'preferred from the stand-l point' of securing more uniform heating.

v v v It may be preferred kto maintain a uniform feed of emulsion .to the :apparatus and to that endit may be preferred to provide a suitable y storage tank for the emulsion, provided with agitating means such asa stirren to prevent stratification'anuzi consequent rapid variation in the yIn the drawing the material recycled in any stagey owsthrough the entire heating zone in y v v admixture with the feed to that heating zone.

Therecycled material'might be united with the feed after the feed had already passed a portion'of the heating zone. f

Other modifications will readily occur to those skilled in the art.

mixturein said stream with said petroleum tarvwater emulsionv undergoing' vaporizatzlon as. to

constituentsfthereof, said vapor-ization and sepav ration being carried out with sumcient rapiditiF to separate inheat polymerizable form andas a part of said vaporized constituents a conside." ablev portion ofy said' heat polymerizable unsafe.V

rated hydrocarbon'm'aterial boilingfabove 200 C. 1'0' when at atmospheric pressure.

3. In va process for the dehydration of a petroleum tar-water emulsionv with theY separation of the constituents of the tar into tar residue and hydrocarbon distillate with decreased polymerization of heat polymerizable unsaturated hydrocarbon material contained in said tar, the steps comprising rapidly-heating a stream comprising f said petroleum tar-wateremulsion in a heating zone, flowing the resulting heated material into a separating zone for the separation therein of vaporized constituents including unsaturated monof merio dead oil materialy from unvaporized constituents including tar residue, after separation removing said vaporized constituents including unf f1 saturated monomeric deadv oil material,v after through :3o

' fresh feedstock being at least as high as 1 part of recycle stock to l part of fresh feed stock. v 4. In a'process for the dehydration ofvapetrorleuln tar-,water emulsion with the separation of f The termI comprisingl isv employed inthe not exclude the presencey of steps and materials other than those recited.v Therefore, changes,.omissions, additions, suby stitutions i and/or modiiications may he made within the scope of the vclaims without departing 40f fronithe spirit of the invention which is limited only as required by the prior art.

I claim:

l. In a process for the dehydration of a peand hydrocarbon distillate with decreased polymerization of heat polymerizable unsaturated hydrocarbon material `contained in said tar, the steps comprising rapidly vaporizing constituents including water and unsaturated monomeric hydrocarbon dead oil'- constituents contained in a stream Acomprising said petroleum tar-water emulsion,

separating vaporized constituents'including uning rapidly vaporizing constituents including wa` claims in its generally accepted meaning and does 35 separation removing said unvaporizedfconstituents, and recycling a portion of said removed unv'aporized constituents to said heating zone for" passage through yat least a part thereof in admixturewith saidpetroleumtar-water emulsion f v in said stream, the proportion ofvzrecycle stock yto the constituents ofthe tar into tar residue and y hydrocarbon distillate with increased recovery in f said hydrocarbon distillate of heat 'polymerizable 1 f unsaturated hydrocarbon material contained in v said tar and which boils above 200 C. when at atmospheric pressure, said petroleum tar-water remulsionhaving been previously treated toy .reduce its content of material boiling below'200 C. when at atmospheric pressure, the steps comtroleum tar-waterV emulsion with the separation -of the constituents ofthe tar into tar residue saturated monomeric dead oil material from 11n- ,55

ter and hydrocarbon constituents above ..70

- 200 C. when at atmospheric pressure contained in a stream comprising said petroleum tar-water emulsion, separating vapor-ized constituents from unvaporized constituents,and recycling a portion prising rapidly heating a stream comprising -said Y petroleum tar-water emulsion in a heating zone to a temperature sufficiently high under the pressure conditions obtaining to vaporize water and hydrocarbon constituents of said tar boiling aboveV 200 C. when at atmospheric pressure including heat polymcrizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure, flowing the resulting heated material into a separating zone for the separation therein of vaporized constituents from unvaporized constituents, after separation removing Vsaidy vaporized constituents including heatv polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure, afters'eparation removing said R0 unvaporized constituents, and recycling a portion of said removed unvaporized constituents to said heating zone for passage through at least a part thereof in admixture with said petroleum'tarwater emulsion in said stream, said vaporization and separation being carried out with suilicient rapidity to separate in heat polymerizable form and as a part of said vaporized constituents a considerable portion of said heat polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure.

5.,In a process for thedehydration of a petroleum tar-water.emulsion with separation.; of

,the constituents .of the tar into tar residue-'and hydrocarbon distillateswith increased recovery of the separated unvaporized constituents'for ad- .75 in said hydrocarbon distillate of heat polymeriaaaecasoo ble unsaturated'hydrocarbon material contained in said tar and which boils above 200 C. when at atmospheric pressure, the steps comprising rapidly owing a stream comprising said petroleum tar-water emulsion through a heating zone at a rate of ow sufcient to produce a high degree of turbulence and rapidly heating said stream therein suiciently under the pressure conditions obtainingvto vaporize water and hydrocarbon constituents boiling below 200 C. when at atmospheric pressure, rapidly separating the resulting vaporized and unvaporized constituents, recycling a portion of said separated unvaporized constituents to said heating zone` for passage through at least a part thereof in admixture with said petroleum tar-water emulsion in said stream, rapidly flowing a stream comprising another portion of said lseparated unvaporized constituents through a second heating zone at a rate of 'flow suicient to produce a high degree of turbulence and rapidly'heating said second named portion of unvaporized constituents therein sufiicie'ntly under the pressure conditions obtaining to vaporize hydrocarbon constituents thereof boiling above 200 C. when at atmospheric pressure, rapidly separating vaporized constituents produced bysaid heating in said second heating zone from unvaporized constituents, and recycling a portion of said last named unvaporized constituents to said second heating zone for pass-age through at least a part thereof in admixture with said second named portion of unvaporized constituents, said vaporizations and separations being carried out sufciently rapidly to separate in heat polymerizable form and as a part of said second mentioned vaporized constituents a considerable portion of said heat polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmosf pheric pressure.

6. In a process for the dehydration of a petroleum tar-water emulsion with the separation of the constituents of the tar into tar residue and hydrocarbon distillate with increased recovery in said hydrocarbon distillate of heat polymerizable unsaturated hydrocarbon material contained in said tar and which boils above 200 C. when at atmospheric pressure, the steps comprising rapidly heating in a heating zone a highly turbulent stream comprising said petroleum tarwater emulsion to a temperature suiiiciently high under the pressure conditions obtaining to vaporize water and hydrocarbon constituents of said tar boiling below 200 C. when at atmospheric pressure but not suiciently high to vaporize a preponderant portion of the volatile constituents contained in said tar which boil between 200 C. and 350 C. Whenfat atmospheric pressure, iowing the resulting heated material into a separating zone for the separation therein of vaporized constituents from unvaporized constituents. after separation removing said vaporized-constituents from said separating zone, after separa-tion removing said unvaporized constituents from said separating zone, recycling a portion of said removed unvaporized constituents to said heating zone for highly turbulent passage through at least' a part thereof in admixture with said petroleum tar-water emulsionin said stream, rapidly heating in a second heating zone a. highly turbulent stream comprising another portion of said removed unvaporized constituents to a temperature sufciently high under the pressure conditions obtaining to vaporize a substantial portion of the volatile constituents thereof boiling between 200 C. and 350 C., owing the heated material resulting from said second heating step into a second separating zone for the separation therein of vaporized constituents from unvaporized constitu'ents, removin-g said last named vaporized constituents from said second separati-ng zone,

lremoving said last named unvaporized constituents from said separating zone, and recycling a portion ofy said last named removed unvaporized constituents to said second heating zone for highly turbulent passage through at least a part thereof in admixture with ysaid second named stream. f

7. In a proces-s for the dehydration of a petroleum tar-water emulsion with the separation oi the constituents of the tar into tar residue and hydrocarbon distillate with increased recovery in said hydrocarbon distillate of heat polymerizable ed material into a. separating zone for the separation therein of vaporized constituents from unvaporized constituents, after separation removing vaporized constituents from said separating zone through phase contacting means, thereafter condensing removed vaporized constituents returning 'a portion of the resulting hydrocarbon condensate to said phase contacting means as reux for the condensation therein of relatively less volatile constituents in said vaporized constituents removed therethrough, after separation recycling a portion of said unvaporized constituents together with at least a portion of said relatively less volatile constituents condensed from said vaporized constituents to said heating zone for passage through at least a part thereof admixture with said petroleum tar-water emulsion in said stream, after separation rapidly heating a stream comprising another portion of saic unvaporized constituents in a second heating zone to a temperature suiciently high under the pressure conditions obtaining to vaporize deac' oil constituents thereof, flowing the resulting heated material into a second separating zone foi the separation therein of vaporized constituent: from unvaporized constituents, after separatior removing said last named vaporized constituents after separation removing said last named unvaporized constituents, and recycling a portion o; said last named unvaporized constituents to saic second heating zone for passage through at least a part thereof in admixture with said last namec stream. l

8.- In a process for the dehydration of a petroleum tar-water emulsion with the separation o: the constituents of the tar into tar residue anc hydrocarbon distillate with increased recovery i1 said hydrocarbon distillate of heat -polymerizabh unsaturated hydrocarbon material contained i1 said tar and which boils above 200 C. when a' atmospheric pressure, ,the steps comprising rapidly heating a stream compri-'sing said petro leum tar-water emulsion togetherwith an adde( aration therein ofvaporized constituents from unhydrocarbon distillate with decreed polymerization of heat polymerizable unsaturated' hydrocarbon material contained-in` said tar, the steps com-v` prising rapidly heating a, 'stream comprising said' I' stituents, removing vaporized constitu' for passage through atleast a part thereof in vaporized constituents from unvaporized conwie from said second separating zone, removing unvaporized constituents from said second separating Azone, and recycling a portion of the unvaporized constituents removed from at 'least one of the vsaid separating zones tothe preceding heating mixture with said stream heated therein, said vaporizations and separations being eiected with sumcient rapidity to separate-in heat polymeriz- -able form and as a part of said second menl tioned vaporized constituents a considerable porpetroleum tar-wateremulsion in a heating zone v.

to a temperature suiiciently high'under theV pressure conditions obtaining to vaporiz'e water and hydrocarbon constituents thereof, ilowing theresulting heated material into a separating'zone for the4 separation therein ofvaporized. constituents from unvaporized constituents; after separation removing said-vaporized constituents, after separation-removing said unvaporized constituents, rapidly heating a stream comprising at least a portion o'f said removed unvaporized constituents in a second heating zonev to a temperature sumciently high under the pressure conditions obtaining to vaporize hydrocarbon constituents thereof which boil above 200 C; when at atmospheric' pressure, flowing the resulting-heated material into a second separating Zone for the removal therein of vaporiZed constituents from unvaporized constituents, removing said -last named vaporized constituents from said secondrseparat'- ing zone, removing saidlast named unvaporized constituents iromsaid second separating zone,

and recycling a portion of the unvaporized'fcon-``- tion of said heat polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure.

11. In a process for the dehydration of a petroleum tar-water emulsion with the separation of 'the constituents of the tar Vinto tar residue and hydrocarbon distillatwith increased recovery inv said hydrocarbon distillate'of heat polymerizable,

unsaturated hydrocarbon material contained in said, tar and which boils above 200` C. when at atmospheric pressure, the steps comprising rap' idly heating a rapidly flowin'g'stream comprising vsaid-petroleum tar-water emulsion in a heating zone to a temperature sufmciently high under the pressure conditions obtaining Ato vaporize water" and hydrocarbon constituents thereof which vboil lbelow 200 C. .when at atmospheric pressure, lflowing the resulting heated material into'a separating zoneior therseparation' thereinfof vaporized constituents fromV unvaporized constituents, after separation removing v'apo'rizedV constituents l from said separating zone,after separation removing unvaporized constituents'from said separating zone, recycling a'p'ortion of said removed unvaporized constituents to said .heating zone for passage throughat least a' part thereof in admixture with said petroleum tar-'water emulsion in said rapidly iiowing stream, rapidly heatstituents removed from 'at least one of said sep-1 Y arating zones to the preceding heating zone for passage through at least a part thereof in admixture with the stream heated therein to produce'a highlyvturbulent flow of said admixture intheA said preceding heating Zone.V Y v Y l0. In a process for'the dehydration of a petroleum tarwater emulsion with the separation of the constituents of the tar into tar residue and hydrocarbon distillate with increased recovery in saidhydrocarbon distillate of heat polymerizable unsaturated hydrocarbon materialcontained in said tar and which boils above 200 C. when at-v atmospheric pressure, the steps :comprising heating rapidly -a stream comprising said petroleum tar-Water'emulsion in a heating z oneto a temperature sufficiently high under the pressure conditions obtaining to vaporize water and hydrocar.. bon constituents of s'aidvtar which boil below 200 C. when at atmospheric pressure, owingtheresulting heated material into a separating zonefor' the separation therein of vaporized constituents from unvaporized constituents, removing said s vaporized constituents from said separating zone, removing said,unvaporized'constituents-from said separating zone, rapidly heatinga streamvcomprising at least a portion of said removed unvaporized constituents in va second heating zone at reduced pressure and to a temperature suiciently high under thepressur'e conditions obing a stream comprising another portion of said removed unvaporized constituents in a second heating zone at reduced total pressure and in the presence of an added gaseous. diluent and to-a temperature su'iiiciently high under the pressure conditions obtaining to vaporize constituents thereof boiling above 200 C. when at atmospheric pressure, flowing the resulting heatedV material .from vsaid secondV heating zoneinto a second separatingizone for the separation therein' of vaporized constituents fromlunvaporized constituents, removing said'last named vaporized constituents from saidzvsecond separating zone, r e moving said last nam'edunvaporiz'edconstituents from said second separating zone, and ,recycling a portion of said last namedremovedunvaporized vconstituents to said second heating 'zone for passage through at least a part thereof iniadmixture with said last named stream,l said vaporizations and separations being ee'cted with suicient rapidity to separate in heat polymerizable formand as a part of said second mentioned vaporized constituents a considerable portion ofzsaidheat Y Y polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric'pressure.

.12. Ina

l leum tar-.water emulsion with the vseparation of taining to'vaporize ,constituents thereof which boil above 200\C .when at atmospheric pressure,

flowing the resultingheated material into asec-` y ond separating zone for the separation therein of u thelconstituents Aof the tar into tar residue and hydrocarbon distillate with increased recovery in' said hydrocarbon distillate of heat polymerizable unsaturated hydrocarbon 'material contained in said/ tar and which boils above 200' C,when at atmospheric pressure, said petroleum tar-water process for the dehydration of apetroi aseaaoo sure, the steps of rapidly owing a stream of said petroleum tar-water emulsion through a heating zone and heating lsaid stream therein to a temperature between approximately 100 C. and 350 C. and sulciently high under the pressure conditions obtaining to vaporize water and hydrocarbonv constituents' of said tar boiling above 200 C. when at atmospheric pressure including heat r llymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure, owing the resulting heated material without large pressure drop into a separating zone maintained at reduced pressure for the separation therein of vaporized constituents from unvaporized constituents,V after separation removing said vaporized constituents including heat polymerizable unsaturated hydrocarbon material boiling vabove 200 C. when at atmospheric pressure, after separation removing said unvaporized constituents, and recycling a portion of said removed unvaporized constituents to said heating zone for Apassage through at least a part thereof in admixture with said petroleum tar-water emulsion in said stream, said admixture being passed through said heating zone with sumcient rapidity to producehighly turbulent now, and said vaporization and separation being effected suiiiciently rapidly to .separate in heat polymerizable form and as a part of said vaporized constituents a considerable portion of said heat polymerizable unsaturated hydrocarbon material boiling above 200 C. when at atmospheric pressure.

13. In a process for the dehydration of a petroleum tar-water emulsion with separation of the constituents of the tar into tar residue and hydrocarbon distillate with increased recovery in said hydrocarbon distillate of heat polymerizable unsaturated hydrocarbon'material contained in said tar and which boils above 200 C. when at atmospheric pressure, the steps of rapidly flowing J a stream of said petroleum tar-waterI emulsion through a heating zone and rapidly heating said stream therein at a temperature between approximately 100 and 350 C. and suciently under the pressure conditions obtaining to vaporize water and hydrocarbon constituents boiling below 200"A C.y when at atmospheric pressure, iiowing the re-A sulting heated material without large pressure drop into a separating zone maintained at approximately atmospheric pressure and therein separating the resulting vaporizve'd and unvaporized constituents, producing a highly turbulent ow of material in said heating zone by recycling a portion of said separated unvaporized constituents to said heating zone for passage through at least a part thereof in admixture'with said petroleum tar-water emulsion in said stream, rapidly owing a stream of another portion of said separated unvaporized constituents through a second heating `zone and rapidly heating said secondmentioned portion of unvaporized constituents therein at a temperature between approximately 100 and 350 C. and suiliciently under the pressure conditions obtaining to vaporize hydrocarbon constituents thereof boiling above 200 C.-

when at atmospheric pressure, owling the resulting heated material without large pressure drop, into a separating Vzone maintained at reduced pressure, and therein separating vaporized constitents produced by said heating in said second heating zone from unvaporized constituents, and

producing a highly turbulent flow of material in said second heating zone by recycling a portion of said last mentioned unvaporized constituents to said second heating zone for passage through at least a part thereof in admixture with said second mentioned portion of unvaporized constituents, said vaporizations and separations being carried out with suflicient rapidity to separate in heat polymerizable form and as a part of said last mentioned Vaporized constituents a considerable portion of said heat polymerizable unsaturated hydrocarbon material boiling above 200 C.

when at atmospheric pressure.

14. In a process for the dehydration of a petroleum tar-water emulsion ,with the separation of the constituents of the tar into tar'residue and hydrocarbon distillate withincreased recovery in said hydrocarbon distillate of heat polymerizable unsaturated hydrocarbon material contained in said tar and which boils above approximately 200 C; when at atmospheric pressure, the steps of -rapidly heatingl a stream comprising said p etroleum tar-water emulsion in a heatingzone to a temperature not exceedingapproximately C. but sufficiently high under the pressure conditions obtaining to vaporize water and hydrocarbonconstituents thereof which boil below 200 C. when .at atmospheric pressure; owing the resulting heated material without-large pressure drop into a separatingA zone maintained at approximately atmospheric pressure for Athe separation therein of vaporized 4constituents from un- V vaporized constituents, after separation removing vaporizedlconstituents from said separating zone, after separation removing unvaporized constituents from said separating zone, producing highly turbulent ilow in said heatingzone by recycling a portion yof said removed unvaporized-constituents to said heating zone for passage through at least a part thereof in admixture with said petroleum tar-Water emulsion insaid stream, rapidly heating a stream comprising another portion of said removed unvaporized constituents in a second heating zone to a temperature not exceeding approximately C. but sumciently high under the pressure conditions obtaining to vapor-A ize constituents thereof boiling above 200 C. when at atmospheric pressure, flowing the resulting heated material from said second heating zone without large pressure drop into asecond separating zone maintained under reduced pressure at least as low as 100 mm. I-Ig.for the separation therein of vaporized constituents from `unvaporized constituents, removing said last mentioned vaporized constituents from said second separat-` ing zone, removing said last mentioned unvaporized-constituents from said second separating zone, and producing highly turbulent now-in said second heating z'one by recycling a portion of said lastmentioned unvaporized constituents to said second heating zone for passagethrough at least va p'art thereofin admixture with said second mentioned stream, said vaporization steps and said separation steps being carried out with suicient rapidity to separatein heat vpolymerizable form and as a part of said last mentioned vaporized constituents a considerable portion of said heat polymerizable unsaturated hydrocarbon material Iboilingabove 200" C. when at atmospheric pressure.

15. In a process for the dehydration of a petroleum tar-water emulsion vvith the separation of the constituents of the tar into tar residue and hydrocarbon distillate with increased recovery inf `said hydrocarbon distillate of heat polymerizable' obtaining to vaporize water and hydrocarbon constituents boiling below 200 C. when at atmos-v pheric pressure, owing the resulting heated material Without large pressure drop into a separating zone and therein separating vaporized constituents from unvaporized constituents, producingV a highv degree of turbulence inthe flow oi' material through said heating zone by recycling la portion of saidseparated unvaporized constituents to said heating z'onevfor passage through at least a part thereof in admixture with said petroleum tar-water emulsion in said stream, rapidly flowing a stream comprising another portion of said unvaporized constituents through-a second heating zoneand rapidly heating said second .mentioned stream therein in the presence of ladded steam to a temperature between approxihmately 100 and 350 Crandsumciently under the pressure conditions obtaining to ,vaporizehydrocarbon constituents thereof boiling above 200 C.

when'at atmospheric pressure, flowing the resulting heated material fromsaid second heating zone without large pressure drop into e second separating zone maintained at reduced pressure and therein separating vaporized constituents produced by said heating in said second heating zone from unvaporined constituents,- and producing ahigh degree of turbulence in the flow of material through said second heating zone by recycling a portion of said last mentioned unvaporized constituents to said second heating zone for passage through at least a part thereof in admixture with said second mentioned streannsaid vaporizations and separations being carried out sumciently rapidly to separate in heat polymerizable form and as a part of said second mentioned vaporized constituents a considerable porl tionof said heat polymerizable unsaturated hyatmospheric pressure.

drocarbon materialv boiling above 200 C. when at r HORACE M wnm.

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