US2423424A - Residual tar separated from tar-water emulsion - Google Patents

Description

9 394? E. a... HALL. ETAL 2 423A24 RESIDUAL TAR SEPARATED FROM TAR-WATER EMULSIQN Filed Dec. 18, 1943 treated according to some method Patented July 1, 1947 52,423,424 FF-lCE RESIDUAL TAR SEPARATED FROM TAR-WATER EMULSION Edwin L. Hall, Manchesteig'N. 11., and Howard R. Batchelder, Drexel Hill, Pa., asslgnors to The United Gas Improvement Company, a corporation of Pennsylvania Application December 16, i943. Serial No. 514,488

Claims. 1

This invention is a continuation-in-part of our copending applications Serial No. 342,735, filed June 2'7, 1940, which has matured into Patent 2,366,899, granted January 9, 1945, and Serial No. 370,608, filed December 18, 1940, which has matured into Patent 2,387,259, granted October 23, 1945.

This invention relates to 'heavy tar or pitch residuum separated from the condensed products of the pyrolysis of hydrocarbonaceous material.

The invention will be more particularly described in connection with residual tar separated from the condensate from pyrolysis products formed during the production of combustible gas by processes involving the pyrolytic decomposition of hydrocarbon oil, with or without the aid of catalysts, and heat polymers of said 'monomeric material.

Various processes are known for the manufacture of combustible gas such as carburetted water gas and oil gas, wherein a petroleum oil such as crude oil or a fraction thereof, for example, gas oil or residuum oil, is. pyrolytically decomposed.

In such processes petroleum oil is pyrolyzed in vapor phase and at reduced partial pressures due to the presence of diluent gas such as blue water gas and/or steam and at relatively high temperatures such as 1300 F. average set temperature and above as measured by standard type shielded thermocouples. I a

In such processes the gas leaving the gas-makingeapparatus 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. Thus 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 diiiers from tars obtained in processes for-the production of coal gas oncoke oven gas, or in many oil cracking processes ior'the production of motor fuel, for in the latter processes the tar as recovered is not in an emulsion form.

The recoveredmixture of tar and water from gas-making operations involving the decomposihowever, separate only the tarand the water of the emulsion and do not separate lighter tar con-' stituents from the heavier. Furthermpre, the presence of free carbon in the rise to operating difliculties.

The separationof the tar emulsion by distillation results in fractions which comprise (1) water, (2) a distillate from the tar comprising I light oil and dead oil, and (3) residual tar.

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 of the distillate boiling above approximately 200 C. (392 F.) at atmospheric pressure will be designated "dead oil. These may be separated by distillation. The residuumremaining after the separation of the light oil and dead oil will be termed residual tar.

The light oil fraction contains, among other things, valuable saturated and unsaturated aro-' matic hydrocarbons such as benzene, toluene, xylene, styrene. methyl styrene, inden'e, etc.

The dead oil fraction contains naphthalene, methyl and other substituted naphthalenes, and may contain anthracene, methyl anthracene, as well as numerous otherhydrocarbons for the most part as yet unindentified.

4 Residual tarhas had a number of uses. For

example, it has been used as a road tar, or as a heavy liquid fuel. For both purposes the control tance because of its eiTect upon the ease of handling. Other uses of residual tar are for exseparation of light oil and dead oil as distillate,

tion of petroleum oil is usually first collected in v a settling tank for the separation of as much water as possible by layer formation and decantation.

In accordance with prior art practice the relatively. stable tar emulsion which remains after separation of the water layeris usually of dehydration such as centrifuging or distillation.

Centrifugal methods of treating tar emulsions.

substantial polymerization of relatively high boiling heat polymerizable unsaturated material in the tar is caused to take place. Such polymerization tends to reduce the quantity of distillate on the to increase the viscosityof the residual tar for any given distillate 'recovery on the other.

These disadvantages are efi'ectively overcome in the practice of the invention described and claimed in our first-mentioned copending ap- ,plication.

In accordance with the process of said firstmentioned copending application, tar emulsions may be dehydrated in a manner (1) such that the yield of dead oil therefrom at the expense of residual tar without encountering a corresponding increase in viscosity of the residual tarzor (2) such that for a given yield emulsion may give of the viscosity of the residual tar is of impormay be increased ventional methods.

Residual tar viscosity is of importance in the art. For example, an' increase in tar viscosity results in an increase in handling difliculty. With the process of said first mentioned copendlng application, more dead oil may be recovered for any given selected residual tar viscosity than by conventional methods for tar dehydration in use at the present time.

In the practice of the process of said first mentioned copending application, a tar emulsion is rapidly heated to an appropriatetemperature and then discharged into a separation zone which may be maintained at any desired suitable pressure, such as under vacuum, under conditions such that (1) the vaporized portion may be rapidly removed, and condensed and cooled to below polymerizing temperatures; and (2) the unvaporized portion may be rapidly removed and cooled to below polymerizing temperatures.

.By these procedures the material in process does not remain at operating temperatures for protracted periods, Thus, polymerization is materially reduced with the result that a larger proportion of the tar itself may be taken off overhead as distillate along with the water while processing the bottom or residual material to any given residual tar viscosity.

It will be understood that two factors affect 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 material removed overhead, and (2) the proportion of unsaturated material polymerized into less volatile, more viscous polymers. In the process of said first mentioned copending application, assuming that other things remain unchanged, item (1) preceding maybe increased and decreased by decrease and increase in the temperature to which the original tar is subjected. However, consideration should be given to the effect of higher temperatures upon item (2) preceding taken in conjunction with heating time, Since polymerization is a function of bot temperature and time, the efiect of higher temperatures during shorter 'heating times may be made the equivalent of the effect of lower temperatures during longer heating times. As described in said first mentioned copending application, we have found, however, that a relatively wide range of both temperature and heating time 'is afforded particularly when operating at subatmospheric pressures, without losing the advantage over conventional methods of tar dehydration.

companied by a considerable quantity of unsaturated aromatic monomeric material boiling in the range of from 210 to 350 C. not readily polymerized by heat but readily polymerizable catalytically, as by catalysts such as H2804, AlClx and BF3.Et2O and others.

The unsaturated monomeric material readily polymerizable by heat tends to be in greater concentration in the higher boiling portion of boiling range from 210 to 350 C., while the unsaturated monomeric material not readily polymerizedby heat tends to be in greater concentration in the lower boiling portion of the boiling range from 210 to 350 C.

The unsaturated monomeric material boilin in the range from 210 to 350 C is accompanied by saturatedhydrocarbons boiling in the same range.

The larger part of the above mentioned heat polymerizable unsaturated monomeric material is so readily polymerizable by heat that it may be. polymerized by heating at 200 C. for two hours. Polymerization at 200, for four hours may produce further resin, after which but little polymerization is effected by longer heating.

- The read ly heat polymerizable high-boiling monomeric unsaturated hydrocarbon material separated overhead in the dead oil boiling range and heat polymers thereof are particularly described and claimed in our said second mentioned copending application.

'In the ordinary methods of distilling tar by batch distillation, the prolonged heating which It has been found that in separating the dead 1 oil and light oil components of the products of petroleum oil pyrolysis from pitch constituents without polymerization or with materially reduced polymerization, that not only may an increased quantity of hydrocarbons boiling in the range from 210 C. to 350 C. and higher be recovered for a given tar viscosity, but a large part of this increase may consist of readily heat polymerizable unsaturated aromatic monomeric material which on polymerization by heat yields valuable resins. This is particularly so'in that portion of the above boiling range above 235 C. and still more particularly so above 265 C.

The readily heat polymerizable material is acis of the order of 16 hours at relatively high temperature, polymerizes this readily heat polymerizable monomeric material,.in and together with the heavy black pitch constituents of the residual tar in which the polymers are lost. As a result the monomers do not appear in the hydrocarbon material boiling in the range of from 210 to 350 C. after separation from the higher boiling pitchy material comprising the residual tar.

The heat polymerizable monomeric material boiling within the range 210 to 350 C. is so readily polymerizable by heat, that in the fractional distillation of the light oil from a dead oil, aportion of the monomeric material is usually unavoidably polymerized and remains as polymer dissolved in the other constituents of the dead oil after the light oil is taken off overhead. The polymerization of theheat polymerizable unsaturated monomeric material in the separated dead oil usually may be completely effected by heating the dead oil with stirring for example for four hours at 210 C.

As a result of separation of the light oil and dead oilcomponents of the products of petroleum oil pyrolysis from the residual tar, without polymerization or with materially reduced polymerization, a substantially pitch free hydrocarbon materal may be separated having a portion boiling within the range of from,2 l0 to 350 C. which contains from 5% to 30% and higher of monomeric unsaturated hydrocarbons readily polymerizable by heat. V

Furthermore, as a result of this separation, a residual tar containing a considerable quantity of unsaturated hydrocarbon material readily polymerizable by heat and possessing an unusual relationship between its content of oily material, its unsaturation, andits viscosity in comparison with residual tar produced by. conventional tar dehydration methods.

The particular concentration of this heat polymerizable material in thedead oil and in the residual tar willdepend upon the amount .of polymerization produced in the separation of the dead oil. from ther residual tar, as well as upon. such factors as the conditions of pyrolysis and the character of the petroleum oil pyrolyzed. other conditions being equal petroleum oils which are characterized as naphthenic in the Bureau of Mines classification de bribed in Bureau of Mines Bulletin -291'as mo ified by Bureau ofMines Report of Investigations 3279 tend to produce more of the .above describedheatpolymerizable material, than oils classified as paraf finic in 1 said Bureau of Mines classification. Petroleum oils of Bureau of Mines Classes to 7 inclusive and cuts from such oils are especially preferred, particularly those of class '7.

Residual tars of particularly desirable characteristics may be separated from the products of pyrolysis of petroleum oil and fractions thereof produced under conditions of relatively uniform and homogeneous cracking with a depth of cracking between that measured by the production of 40 and 80 cubic feet of residual oil gas per gallon of oil pyrolyzed and more pref- -erably between 45 and 65 cubic feet.

By residual oil'gas is meant the vuncondensed final gas after removal of substantially all water vapor or after correction for the presence of water vapor, and after the removal of substantially all hydrogen sulfide or after the, correction for the presence of hydrogen sulfide (unless the oil is low in sulfur content in which case the hydrogen sulfide is negligible for calculation of residual oil gas), and after removal of substantially all hydrocarbons having more than three carbon atoms, or after correction for the presence of such hydrocarbons having more than three carbon atoms, and aftercorrection for thepresence of gas not derived from the oil cracked such'as air and combustion gases from fuel used for heating, and after correction for any water gas which may be present.

By homogeneous cracking it is intended to embrace conditions such, for instance, as concentration of oil vapors, space velocity, turbulence,

surface-volume relationships or the interior of the cracking vessel '01 vessels and character 'of heated surfaces which are such that in any given plane normal to the flow of materials, the materials throughout the plane have previously had substantally the same opportunity to be heated and to undergo the alternate decompositions and, 'synthesis which comprise cracking and which progress toward products of greater thermal stability under the environment obtaining.

Other conditions being fixed, variation of any .one of the following factors inthe direction cited is considered to tend toward less homogeneity in the cracking operation; (1) decreased surface/volume ratio 'of the cracking vessels beyond the vaporizing zone; (2) reduced atomization of the oil; (3) increasedimpingement of oil on highly heated surfaces prior to vaporization; (4) increased concentration of the oil vapors; (5)

riod, the quantity of oilgas produced (and the gree of variation will depend among other factors,

upon the lengthof the oil-cracking run, the oil Y and steam input. rates, the presence or absence cycle may be reduced by reducing temperature swings during the cycle which is favored by use of a relatively short cycle and/or by the employment of highly conductive heat storage material. 1 Therefore, the environment of oil pyrolysis hereunder is advantageously arranged to provide not only relatively homogeneous cracking but also'relatively uniform cracking;

h A convenient measure of the homogeneity and uniformity of the cracking operation is the relation between the sulfonation residue and the free carbon in the condensate from the gas, as will hereinafter appear.

A Sulfonation residue is a measure of the normally non-gaseous paralfines and naphthencs surviving the cracking operation, and hence, high sulfonation residue is an indication of light cracking. Free carbon, on the other hand, is an end product in the pyrolysis of hydrocarbons, and

40 hence, high free carbon indicates severe crack-' High sulfonation residue together with high free carbon indicates that both light and severe cracking have taken place during the cycle and,

hence, is an indication either of great lack of homogeneity of cracking, or of great lack of uniformity of cracking, or .both.

Methods for the determination of Residual oil gas and uniformity and homogeneity of cracking are described in copending application Serial No. 372,074, filed December 28, 1940, by Newcomb K. Chaney and Edwin L. Hall, which has matured into Patent 2,383,772; granted August 28, 1945, the disclosure of which in its entirety is made a part of this specification by reference thereto.

- The residual tar on separation from the dead oil contains a considerable content of heat poly-- merizable material and for a given viscosity contains a, substantially lesser quantity of oily material as measured bythe quantity of distillate recoverable from it under certain test conditions tobe set forth hereinafter. i

, After separation from the dead oil for some purposes it is desirable to cool the separated redecreased turbulence; and, (6) increased space 35 sidual tar rapidly so as to recover it with as little :flvelocity except as effecting turbulence.

In addition to relative homogeneityof cracking which as defined would permit 'wide'changes in cracking conditions during a cycle, it is preferred that the cracking conditions also be what is termed herein relatively uniform during the cycle.

I l In a cyclic operation in which oil cracking chambers are heated during a heating period and the stored heat utilized during the cracking pepolymerization of the polymerizable constituents as possible. For other purposes. for example, where a material of higher melting point is desired, it may not be necessary to rapidly cool the separated residual tar which may be allowed to remain at relatively high temperature or which may be further heated to 'eifect polymerization of its heat p-o'lymerizable content and so increase its melting point without distilling off its oily constituents; Such operations may be carried out I of supplementary heating during the run, the

in the dehydrating apparatus, However, it may be considered convenient to remove the residual tar from the dehydrating apparatus with a relatively low viscosity because of much greater ease of handling, even though the viscosity of the removed residual tar is to be subsequently increased by polymerization.

As a result. of the separation as a part of the dead oil of a considerable quantity of monomeric unsaturated heat polymerizable material boiling in the range of from 210 C. to 350 C. and higher including such material boiling above 250 C, and material boiling above 300 C., ,and also as a result of decreased polymerization of the unsaturated heat polymerizable material not carried overhead with the dead oil, the character of the residual tar differs from that produced in conventional processes of tar dehydration.

It will be seen that for a given, residual tar viscosity a larger quantity of distillate is taken oil? in the operation of the process of said first mentioned copending application than in conventional tar dehydrating methods. As a result the residual tar for a given viscosity contains a smaller quantity of distillable oils. Also, as a resuit of the removal of distillate under conditions which minimize polymerization of heat polymerizable material, the residual tar contains a substantial quantity of heat polymerizable material. In other words, the viscosity of the tar has been arrived at more by removal of distillate and less by polymerization. for the high boiling heat polymerizable material removed in the course of the increased distillate removal has no opportunity to contribute by polymerization to an increase in viscosity of the residual tar.

In other words, one of the outstanding advantages of the process of said first mentioned copending application, in addition to the recovery of much larger percentages of dead oil than have heretofore been possible, without disadvantageously affecting the recovery of light oil either quantitatively or qualitatively resides in the recovery of a residual tar of novel characteristics.

If desired the residual tar of the present invention may be produced by operating the process of our first mentioned copending application in accordance with the improvement described and claimed in copending application ,Serial No. 401,966, filed December 1, 1941, by Horace M. Weir, which has matured into Patent 2,366,900, granted January 9, 1945. In this modification of the process of our first mentioned copending application, separated bottoms in any one or more stages are recycled together with the fresh feed to the stage heating zone.

A two or more stage process is particularly recommended in cases where the tar emulsion contains relatively high percentages of light materials such as benzene, since the first stage permits such materials to be condensed at a higher pressure than might be desired in the second stage,

tion temperature and time of contact while still securing the advantages of the process.

In connection with the production of heat polymerizable unsaturated monomeric material boiling within the range from 210 to 350 C. and recovered in the dead oil the shorter times of contact tend to produce greater yields of this material. Y

The important factor in this respect is the separation of these materials from the residual tar without prolonged heating in contact with the pitchy materials of the residual tar. Stated in other words the greater the extent to which the polymerization of these'materials into the residual tar is avoided, the higher the yield.

Likewise, with respect to the residual tar, the greater the extent to which the polymerization of the unsaturated readily heat polymerizable material boiling above 210 C.-is avoided, the lower the quantity of oily material that may be recovered from the residual tar of a given viscosity, and the greater the heat polymerizable content that may be present in the residual tar of a given viscosity.

After the separation, if the melting point of the tar is to be raised by polymerization of the heat polymerizable material contained therein, it is not so important to avoid its polymerization in the separation apparatus except that handling difliculties increase with increase in viscosity of the residual tar.

Other processes of separation of light oil and dead oil from the pitchy constituents of residual tar, which avoid polymerization of these high boiling heat polymerizable materials prior to their separation from the residual tazymay' be employed in the production of novel residual tar of the character described.

Referring to the drawing:

In this figure, curves A, B, C, and D show relationship between (1) the viscosity of the residual tar, when measured in SSU 210 F., and

(2) its content or distillable oil, as measured by A the quantity of oil recoverable from the residual tar, when it is distilled under an absolute pressure of 11 mm. Hg to an end vapor temperature of 180 C., expressed in per cent by weight of the original residual tar.

The curves are illustrated as plotted on a log chart with the viscosity in SSU 210 F. plotted as the ordinate and the percent by weight of oil distillate as above defined plotted as the abscissa.

The region to the left of curve A embraces viscosity-oil distillate relationships of residualtar which with or without further polymerization comes within the scope of the present invention. As one moves to the left progressively from curve A to curves B, C, and D one progressively enters more preferred regions of diminished distillate content for a given viscosity.

particularly if it is desired to take a considerable quantity of high boiling material ofi overhead in the second stage.

Apparatus for a three or more stage treatment will become apparent to persons skilled in the art upon becoming familiar with the foregoing.

Many other variations may be made.

As stated in said copending applications Serial No. 342,735. which has matured into Patent No. 2,366,899, granted January 9,1945, and Serial No. 401,966, which has matured into Patent No. 2,366,900, granted January 9, 1945, considerable variation may be made in the tar distilla- The following are examples of the determination of the distillable oil content of our residual tars and show residual tars having viscosity-oil distillate relationships within the area defined by the curves.

Example 1 A sample of residual tar separated by the process of, our first mentioned copending application from the products of the vapor phase pyrolysis of a naphthenic oil of class 7 according to the before mentioned Bureau of Mines classification and pyrolyzed under conditions of relatively uniform and homogeneous'cracking as before defined and with a residual oil gas productions within the preferred range before set forth was found to have a viscosity of 10670 SSU 210 F.

The sample was distilled to an end vapor temperature of 180 C. under an absolute pressure of 11 mm. Hg as above described in connection with the drawing. The yield of distillate was found to be 8% by weight of the sample.

Example 2 ture of 180 C. under an absolute pressure of 11' mm. Hg. The yield of distillate was found to be 12% by weight of the sample.

Innumerable other examples might be given. At very high viscosities for example, those above 20,000 SSU 210 F., the content of distillate oil under the conditions set forth is low and very considerable care must be exercised in its proper determination.

The residual tars of our invention, as separated from the light oil and dead oil, are characterized by a relatively high content of heat polymerizable'hydrocarbon material for their viscosity-oil distillate relationship and are unique in this respect.

For the purposes of this application, the unsaturated heat polymerizable content of the residual tar is measured by the increasein the melting point of the residual tar, when the residual tar is heated for 12 hours at 180 C. under conditions of total reflux.

All melting points recited in this application are to be considered as determined by the A. S. T. M. ball and ring method of A. S. T. M. standard D-36-26. f

Under these conditions increases in melting point from 20 C. and less to 50 C. and more may be secured depending upon the degree to which polymerization has been avoided in the separation of particular residual tar measured.

The melting point of the residual tars increases with viscosity, for example, a melting point of approximately 25 C. has been noted associated with a viscosity of 800 SSU 210 F., melting points in the range of approximately 40 C. to 50 C. associated with viscosities of the order of 3750 SSU 210 F. and melting point of the order of 55 C. associated with viscosities of the order of 7500 SSU 210 F.

It will be readily understood by those skilled in the art that the precise quantity of heat polymerizable material associated with a given viscosity-oil distillate relationship at the time of separation of the residual tar from the light oil and dead oil may be varied considerably depending upon the degree to which polymerization has been avoided in the separation process and that residual tars over a wide range of viscosities may be separated from the dead oil and light oil.

It will be understood that the residual tars of very high viscosities may be separated from the dead oil and light oil, even up to viscosities as high as 30,000 SSU 210 F, and more, but I due among other things to. much greater ease of handling it is preferred to separate residual tars having viscosities not exceeding 20,000 SSU 210 F. and more preferably not exceeding 10,000-SSU 210 F.

Because very low viscosities are associated with small separation of dead oil constituents it is preferred to separate residual tars of viscosities of at least 1500 SSU 210 F. and better yet 2000 SSU 210 F. The range of viscosities between 3000 SSU 210 F. and 10,000 SSU 210 F. is most preferred, not only because of ease of handling, but because of other characteristics of the separated tar.

Inasmuch as a high content of heat polymerizableunsaturation as measured above, permits the separation of a residual tar of relatively low viscosity and hence one which may be handled with ease, while still permitting the production of a high melting product by polymerization, residual tars containing a suflicient heat polymerizable unsaturation to cause an increase in melting point upon polymerization of at least 30 C. are more preferred, while those capable of an increase in melting point of at least 40 C. or .at least 50 C, are especially desirable.

In other words it is preferred, other conditions being the same, for any given desired melting pointto separate the residual tar at as low a viscosity as possible and still be able to attain the desired melting point in the desired manner.

We have found in the application of the separation process of our first mentioned copending application to tars produced in the vapor phase pyrolysis under conditions of uniform and homogeneous cracking of petroleum oils of Bureau of Mines classes 5 to 7 as before described and with a depth of cracking measured by the range of residual oil gas productions previously set forth, unusually desirable residual tars may be recovered.

Such residual tars in addition to the characterizations previously set forth, may be characterized by certain specific properties of the oil which they contain which is distillable under the conditions previously defined.

Among such properties the following may be mentioned. Mixed aniline point in the range from 4.0 to 14.0 0.

For certain purposes residualtars containing oil with lower mixed aniline points such as from i to 10 or 4 to 8. are especially preferred. Such residual tars are highly aromatic and the oil has high solvent power.

It is not intended to limit the invention to residual tars from thepyrolysis of naphthenic oils and residual tar having distillable oil of widely differing characteristics from those set forth above is not excluded from its scope. Residual tars with distillable oil of higher aniline point may be particularly desirable for certain uses, i -liowever, our residual tars separated as previously set forth from the preferred pyrolysis proddeveloped for the analysis of bituminous mate'- rials such as those described in Research Paper .RP1387, Journal of Research of the National Bureau of Standards, volume 26, May 1941, page 415, and the technique of Marcusson as described by Abraham in "Asphalts and Allied Substances, 4th edition. These publications give the names asphaltenes,,carbenes, carboids, asphaltic resin and liquid oily constituents to materials extracted, precipitated, polymerized, etc., by the procedures therein set forth.

We have adopted this nomenclature for convenience to define the materials separated from our residual tar by the same techniques. It is to be understood however that this adoption of these names by us does not at all mean that the materials so separated are at all identical with materials so separated from other bituminous substances. As a matter of fact the so called asphaltenes and asphaltic resins particularly as produced from our residual tar by the separation technique employed have properties which differ markedly from the properties of asphaltenes and asphaltic resin produced by .the same technique from other bituminous materials.

It is to be understood also that specific proportions of asphaltenes, carbenes, carboids, asphaltic resin, and liquid oily constituents" as may be mentioned herein refer to proportions as determined by the specific techniques referred toand not to absolute proportions.

With the above qualifications the following definitions are made for convenience in describ ing the preferred additional properties of our residual tars.

Asphaltenes are the portion of the residual tar insoluble in pentane and soluble in G014. "Carbenes" are the portion of the residual tar insoluble in pentane and insoluble in C014. Free carbon" or. carboids are the portion of the residual tar insoluble in pentane, C014 or in benzene.

Of the portion of the residual tar which is soluble in pentane, asphaltic resin is the'portion which is polymerized by the action of fullers earth, the resulting. polymer being soluble in ether, while liquid oil constituents are the portion of the pentane soluble material which is unpolymeri'zed by the action of fullers earth and is soluble in ether. The term liquid oily constituents is not to be confused with the oil which is distillable from the residual tar under the conditions previously set forth.

The determinations of the asphaltenes, asphaltic resins" and liquid oily constituents are bythe' methods set forth in Research paper RP1387.Journal of Research of the National Bureau of Standards, volume 26, May 1941, page 415.

The determinations of carbenes" and carboids" are by the method of Marcus'son as set forth by Abraham in "Asphalts and Allied Substances," 4th edition, except that the carbenes and carboids are determined on the material insoluble in pentane instead of the material insoluble in petroleum naphtha as in Abraham.

Preferably in our residual tars the content of free carbon or carboids does not exceed 25%, and more preferably does not exceed 15% and still more preferably does not exceed 10% by weight of the total material insoluble in pentane.

Furthermore, the total content of asphaltenes" or material which is soluble in CCh and insoluble in pentane is preferably .at least 70% by weight of the total material insoluble in pentane. For some uses it is also preferable, that the carbenes shall not total more than 20% by weight and more preferably not more than 10% by weight of the total material insoluble in pentane,

under conditions of total reflux at 150 C. for

various lengths of time.

Table 1 Residual Tar Residual Tar Polymer Melting Point A. S. Melting 'r M Ball a nd Ring Strait teat-51- Manama 210 F. and Ring 3 hrs. 6 hrs. 13 hrs.

Many other examples of our residual tar polymer could be given with higher and lower melting points. Melting points exceeding C. may be attained in the production of residual tar polymer from our residual tars of relatively high viscosity.

Our residual tars and residual tar polymers having melting points over a wide range are desirable products for many uses.

For certain purposes our materials of low melting point possess advantages. For other purposes our materials of higher melting point are preferred.

Our residual tars and residual tar polymers having melting points from 50 to 100 C, and higher are or may be used to great advantages in formulations for rubber, both natural and synthetic, intended for a wide variety of uses. Reference is made to copending application Serial No. 514,490, filed December 16, 1943, by Philip Edward Rollhaus. The desired melting point of the residual tar or residual tar polymer employed may vary widely depending uponthe particular type of rubber and the particular use to which the rubber is to be put.-

Our products are particularly adapted for advantageous use as softeners in formulations of synthetic rubber or elastomer of many types and particularly those produced by the polymerization of diolefines and/or by' the copolymerization of diolefines with each other and/or with other polymerizable material. Examples are polymers of butadiene, isoprene, piperylene and 2-chlorobutadiene either alone or as copolymers 13 with each other and/or with other materials such as olefines, unsaturated nitriles, acids, esters, ethers, ketones, aldehydes, and substituents thereof, such as styrene, acrylic nitrile, isobutyh enes, acrylic esters, and the like.

Important examples of synthetic rubbers or elastomers are those obtained by the copolymer-.

ization of one or more diolefines with 1) styrene or substituents thereof, (2) acrylic nitrile, and/or sulfides or polysulfides are also included, such as,

for example, the material prepared by the reaction of ethylene dichloride with sodium tetra sulfide and sold under the name of Thiokol.

In synthetic rubber formulations for certain purposes it is advantageous to employ. residual tars and/r residual tar polymers of relatively low melting points, such as below 60 C. In other formulations and for other uses it is advantageous to employ our materials of higher melting point such as from 60 C. to 75 C., from 70 C. to 80 C., or from 90 C. to 100 C. and higher.

The melting point of residual tar polymer may be further raised by a combined heat polymerization 'and distilling operation, by means oi which not only is an increase in melting point due to polymerization efiected but a further increase due to the removal of associated oil. An example of such procedure is the heating ofthe residual tar for 12 hours at 200 C. while simultaneously passing stripping steam through the hot tar. By such procedure melting points of well over 100 C. may be-readily attained.

Our residual tar polymer preferably has characteristics as to asphaltene and"carboid content which fall within the preferred. ranges previously set forth in connection with the description of our residual tar.

Under certain conditions when the residual tar and residual tar polymer is employed in .rubber formulations, it may be preferred to exceed the proportion of carboids set forth above, particularly when proper adjustment is made in the proportion offiller employed, such as carbon black. Our residual tar and residual tar polymers are usually black materials when viewed as thick masses by reflected lights When viewed as thin films by transmitted light, they are generally reddish. The residual tar polymers of high melting point, such as those of melting point above 80 C., more particularly those of melting point above 90 C., and most especially those of melting point above 100 C., are relatively dry, solid materials which are capable of being readily crushed and powdered,

Our residual tar and residual tar polymers prior to subsequent treatment and modification to which they may be subjected, are" substantially hydrocarbon in nature and are largely free from oxygenated compounds and nitrogen compounds. Even after being blown with air of relatively eleuses may be mentioned their employment as ingredients in inks, pigments, roofing and floor compounds, caulking compounds and in other compositions, together with other materials such as fillers and solvents. They may be compounded with many resins, and other materials such as fillers, solvents, etc.

It will be understood that the foregoing specific examples are given by way of illustration, and, that changes, omissions, additions, substitutions and/or modifications might be made within the scope of the claims without departing from the spirit of the invention. 9

'As before statedresidual tar polymer may be produced by allowing the separated residual tar to polymerize in the separation apparatus. Also, additional heat may be supplied to increase the polymerization there. It is preferred, however, to conduct the major part of the polymerization after removal from the separation apparatus.

We claim: o 1. Residual tar separated from tar-water emuision produced during condensation in the pres v ence of H20 of the products of the vapor phase pyrolysis. at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a, viscosity-distillable. oil relationship within the areaof viscosity-distillable oil relationships lying tothe left of the curve having the formula log 1 :8.29-339 log a: in which 11 and :c are respectively rectangular coordinates of visoosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, and having a content of heat polymerizable unsaturated material at least sufiicient to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is heated under conditions of total reflux for 12 hours at 180 C.,

2. Residual tar separated from tar-water emul- 40 'sion produced during condensation in the presvated temperature, their oxygen content is low compared with many other bituminous materials.

Our residual'tars and residual tar polymers may be advantageously employed in many uses in addition to those recited above, among such ence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a-viscosity between 1500 SSU at 210 F. and 30,000 SSU at 210 F., and having a viscositydistillable oil relationship within the area of viscosity-distilla-ble oil relationships lying to the left of the curve having the formula lpg y=8.29-3.39 log a: in which 11 and ac" are respectively rectangularcoordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, and having a content of heat polymerizable unsaturated material at least suflicient to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is.

heated at 180 C. for 12 hours under of total reflux,

3. Residual tar separated from tar-water emulsion produced during condensation in the presence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity between 3000 SSU at 210 F.

conditions and 10,000 SSU at 210 F'., and having a viscositydistillable oil relationship within the area of viscosity-distillable oil relationships lying to the left of the curve having the formula log y=6.85-2.67 log a in which y and a: are respectively rectangular coordinates of viscosity expressed in ,SSU 'at 210 F. and distillable oil expressed in percent by weight, and having a content of heat polymerizable unsaturated material at least sui'ficient-to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is heated at 180 C. for 12 hours under conditions 1 of total reflux.

4. Residual tar separated from tar-water emulsion produced during condensation in the presence of H of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity between 2000 SSU at 210 F. and 20,000 SSU t 210 F., and having a viscositydlstillable oil relationship within the area of viscosity-distillable oil .relationships lying to the left of the curve having the formula log y=7.57-3.03 log a: in which 11 and a: are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, and having a content of heat polymerizable unsaturated material at least suflicient to cause an increase in the melting point of said residual tar of C. when said residual tar is heated at 180 C. for 12 hours under conditions of total reflux. I

5. Residual tar separated from tar-water emulsion produced during condensation in the presence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity between 3000 SSU at 210 F. and 10,000 SSU at 210 F., and having a viscositydistillable oil relationship within the area of viscosity-distillable oil relationships lying tothe left of the curve having the formula log y=6.05-2.26

log a: inwhich y and a: are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, and having a content of heat polymerizable unsaturated material at least sufficient to cause an increase in the melting point of said residual tar of 50 C. when said residual tar is heated at 180 C, for 12 hours under conditions of total reflux.

6. Residual tar separated from tar-water emulsion produced during condensation in the presence of I-IzO'of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of naphthenic petroleum oil, said residual tar having a viscosity between 1500 SSU at 210 F. and 30,000 SSU at 210 F., and having a viscosity-distillable oil relationship within the area of viscosity-distillable oil relationships lying to the left of the curve having the formula log y=8.29-3.39 log a: in which 11 and a: are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, said residual tar having a content of heat polymerizable unsaturated material at least sufficient to cause an increase in the melting point of said residual tar -of 20 C. when said residual tar is heated at 180 C for 12 hours under conditions of total reflux, and the distillable oil content'of said residual tar being characterized by having a refractivity intercept in the range from 1.09 to 1.11 inclusive.

7. Residual tar separated from tar-water emulsion produced during condensation in the presence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity-distillable oil relationship within the area of viscosity-distillable oil relationships lying to the left of the curve having the formula log y=8.293.39 log a: in which y and at are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, said residual tar having a content of heat polymerizable unsaturated material at least sufficient to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is heated under conditions of total reflux for 12 hours at 180 C., and said residual tar being further characterized by a carboid content not exceeding 25% by weight of its pentane insoluble content.

8. Residual tar separated from tar-water emulsion produced during condensation in the presence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity between 1500 SSU at 210 F. and 30,000 SSU at 210 F., and having a viscositydistillable oil relationship within the area of viscosity-distillable oil relationships lying 'to the left of the curve having the formula log y=8.29-3.39 log :1: in which y and a: are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, said residual tar having a content of heatpolymerizable unsaturated material at least sufiicient to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is heated at 180 C. for 12 hours under con ditions of total reflux, and said residual tar being further characterized by having a carboid content not exceeding 10% by weight of its pentane insoluble content and an asphaltene content of at least 70% by weight of its pentane insoluble content.

9. A high-melting tar produced by heating to considerably increase its melting point of a residual tar separated from tar-water emulsion produced during condensation in the presence of H20 of the products of the vapor phase pyrolysis at average temperatures above approximately 1300" F. of petroleum oil, said residual tar having a viscosity-distillable oil relationship within the area of viscosity-distillable oil relationship lying to the left of the curve having the formula log y=8.29-3.39 log .1: in which 11 and a: are respec-- residual tar is heated under conditions of total reflux for 12 hours at 180 C.

10. A high-melting tar produced by heating to considerably increase its melting point of a residual tar separated from tar-Water emulsion produced during condensation in the presence of H2O of the products of the vapor phase pyrolysis at average temperatures above approximately 1300 F. of petroleum oil, said residual tar having a viscosity-distillable oil relationship within the area of viscosity-distillable oil relationship lying to the left of the curve having the formula log y=8.29-3.39 log a: in which 11 and a: are respectively rectangular coordinates of viscosity expressed in SSU at 210 F. and distillable oil expressed in percent by weight, said residual tar having a content of heat polymerizable unsaturated material at least sufficient to cause an increase in the melting point of said residual tar of 20 C. when said residual tar is heated under conditions of total reflux of 12 hours at 180 C. and said residual tar being further characterized by carboid content not exceeding 25% by weight of its pentane insoluble content.

EDWIN L. HALL.

HOWARD R. BATCHELDER.

(References on following page) 17 REFERENCES CITED Number The following references are of record in the 1,992,752 file of this patent: 2,069,929 UNITED STATES PATENTS 5 Number Name Date 1,987,085 Thurston Jan. 8, 1935 Name Date Kershaw Feb. 26, 1935 Swanberg Feb. 9, 1937 Bennett Dec. 31, 1935 Thomas et a1 Mar. 14, 1939

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