US2687989A - Asphalt production - Google Patents

Description

ug- 31, 1954 H. s. GOODWIN ASPHALT PRODUCTION Filed Nov. 30. 1951 mi i AIL Patented Aug. 31, 1954 UNITED STATES PATENT DFFICE ASPHALT PRODUCTION Henry S. Goodwin, Aruba, Netherlands West Indies, assigner to Standard Oil Development Company, a corporation of Delaware Application November 30, 1951, Serial No. 259,133

3 Claims.

This invention concerns a novel process for producing asphalts from bituminous materials obtained from crude petroleum oils. The process concerns particular blending and reduction procedures to provide a wide variety of asphalt products, having desirable properties, in a manner to permit production of optimum yields of high quality asphalt products. In particular this invention permits successful blending of asphaltic materials to provide homogeneous asphalt products which have heretofore been blended to provide heterogeneous asphalt products.

A number of techniques are now known for producing asphalts of varying physical properties from petroleum crude oils, or fractions thereof, which contain asphaltic materials. For example, a variety of processes have been suggested for producing asphalts by reduction of petroleum fractions containing asphalts, by oxidation of asphaltic materials, and by various blending operations. Limitations of presently known asphalt processing operations, however, limit the range of different properties obtainable in the nal asphalt products. Again, combinations of properties such as the susceptibility factor, the flash point, and the ductility of the final asphalt product are limited by the pres-` ent processing techniques.

In this connection, for example, the temperature susceptibility characteristics of asphalts obtained by the reduction of asphaltic materials found in a given petroleum oil are in many cases less desirable than might be required. It is a principal objective of this invention therefore, to permit obtaining asphalt susceptibility characteristics which are substantially improved over those obtainable by presently known processes.

The process of this invention by means of which these and other objectives are attained is a basically new treating process sequence. The process permits production of asphalts of improved physical properties and provides a relatively limitless range of combinations of physical properties for asphalts from a given crude source. The process entails the blending of particular types of asphaltic materials followed by the reduction of these materials to a desired consistency. Uniquely it has been found that by these simple processing steps of blending and reducing, it is possible to obtain the indicated advantages.

The nature of this invention can be well understood by reference to an asphalt property generally designated as homogeneity. This property concerns what has been referred to as 2 'the complete amalgamation of the asphalti constituents present in an asphaltic product. Heterogeneity, as opposed to homogeneity, refers to the imperfect blending of bituminous constituents, and is usually indicative of the presence of unsaturated compounds. While heterogeneity of asphalt products may be tolerated for certain applications, ingeneral homogeneous asphalt products are preferred, and are required for many applications. For example, paving grade asphalt products must be homogeneous in nature to meet specification limitations and to Supply the requirements of actual use. A heterogeneous paving asphalt will exhibit poor aging and weathering characteristics.v

Some heterogeneous asphaltic materials have very desirable properties which are not ordinarily obtainable in combination with other desirable properties found in homogeneous asphalts. Blending of heterogeneous with homogeneous asphaltic materials to obtain such combinations of properties has heretofore produced heterogeneous products. By means of the process described in this patent it is now possible to blend heterogeneous with homogeneous asphaltic materials, and obtain the desired combinations of properties, and at the same time produce homogeneous asphalts.

This is accomplished by a simple two-step processing sequence, necessitating the blending of the asphaltic materials to be combined, followed by a reducing operation conducted to drive off a distillate portion of the blended asphaltic materials. In some manner which is not presently understood, the reducing step is operative to convert what would otherwise be a heterogeneous product to a homogeneous asphalt. This makes possible the production of homogeneous asphalt products having heretofore unobtainable properties and combinations of properties from an originalcrude source.

In the practical application of this invention, the two materials to be initially combined must be particularly chosen. The materials may generally be designated as a heterogeneous asphaltic material generally having a low susceptibility factor and a homogeneous asphaltic material generally having a higher susceptibility factor. As exemplary of the first class of compounds, reference may be made to tars, particularly tars which have been derived from mild petroleum cracking operations on asphaltic crudes, and to oxidized asphalts such as derived from asphaltic reduced crude oils. Such asphaltic materials, that is, such tars and oxidized asphalts are char- 'distillation column 3.

acterized by susceptibility lfactors lower than about 3.3. In this connection, and as used herein, susceptibility factor may be defined as the ratio of the penetration of the asphaltic material at 25 C. per 100 g. per 5 seconds to the penetration of the asphaltic material at C. per 200 g. per 60 seconds. As stated, these asphaltic materials are normally heterogeneous as determined, for example, by what is known-as the Olienses test.

The other of the two asphaltic materials to be combined may be defined as a low softening point reduced asphalt obtained from an asphaltic crude oil or reduced crude oil. Such an asphaltic material is normally homogeneous and possesses a relatively higher susceptibility factor, extending up to about 14. The invention is of particular application when employing a reduced asphalt having a susceptibility factor of about 3.3 to 6.

In the nrst step of the process therefore, a heterogeneous asphaltic material, such as a tar or oxidized asphalt, is mixed with a homogeneous asphaltic material such as a reduced asphaltic crude or asphalt. It is critical, in this step of the process, that particular proportions of these two asphaltic materials be combined. For the purposes of this invention it has been found that not more tha-n about 35% of the heterogeneous material may be combined with the homogeneous material. For some reason, if more than about 35% of the heterogeneous material be included in the combination, it is not always possible to obtain a iinal asphalt product which is homogeneous. It has been found that, in fact, from 15 to 25% of the heterogeneous material is best blended with the homogeneous material. On the mixing of these two asphaltic materials, a heterogeneous asphaltic material is obtained. This heterogeneous material is then reduced to a desired consistency so as to obtain a. nal product in yields of not more than about 97% based on the heterogeneous mixture. The reduction may be carried out by means known to the art, but will generally and preferably entail distillation of the asphaltic material under reduced pressures to secure the removal of about 3% or more of the more volatile constituents. Depending upon the asphaltic materials originally combined and the desired properties of the final asphalt product, as much as 50% or more of the volatile constituents can be removed in this manner. It is a peculiarity of this processing operation and, in fact, a basic discovery that this reduction is operative to render a homogeneous asphalt product. In general, this asphalt product will be characterized by particular asphalt properties and combinations of asphalt properties not otherwise obtainable by the processing of asphaltic materials from a given crude oil. In securing this result it is critical that at least some elimination of the more volatile constituents present be obtained which, as indicated, must be more than about 3%.

The process of this invention may be readily understood by reference to the accompanying drawing which diagrammatically illustrates a preferred embodiment of the invention. A petroleum crude oil may be employed as a feed material to be passed through. line I, heat exchanger 2 and a pre-heating furnace for introduction to Distillation column Il may comprise a conventional type of still for the fractionation of a crude oil into a variety of petroleum fractions including a reduced crude oil fraction to be removed from the still 4 through bot- `cnude oil isreduced in this manner, and, in fact,

may, if desired, incorporate the entire crude oil provided that the crude contain asphaltic materials. This crude or reduced crude oil thus provides an asphaltic material of a homogeneous character having a low softening point and characterized by a susceptibility factor which may extend up to vabout 14. In other words, the temperature susceptibility of this reduced asphaltic material, as derived from a crude oil, may be poor in nature. This asphaltic material withdrawn from still 4 through line 5 is then split into two streams, 6 and '1. The stream of line @may be directly introduced to blendingapparatus I I, wherein it is mixed with a higher softening point, heterogeneous asphaltic material introduced to the blender through line 9. The

.higher softening point blending component may constitute a petroleum tar or oxidized asphalt.

Again, this blending component may constitute aheterogeneous asphaltic material which maybe derived fromthe original crude oil. For example, the stream of line "I may be subjected to air blowing or cracking in zone 8 to kprovide an oxidized asphalt or tar of this character. The material is characterized by a low susceptibility factor generally less than about 3.3. It is necessary to heat the tar or the oxidized asphalt to an elevated 'temperature of about 20T-450 F., to reduce viscosity sufficiently to permit blending. For this purpose the material may be passed through a pre-heating furnace I5 prior to introduction to blender II.

The two asphaltic materials introduced to blending apparatus II are maintained at a suflciently hightemperature to permit ready mixing under the iniiuence of agitation appliedas by means of the propeller stirrers illustrated in the blending apparatus I I. As a result of this blending operation, a product may be withdrawn through line I2 constituting a heterogeneous mixture of the reduced crudeasphaltic material and the higher softening point blending component. 'Thismixture is passed through a preheater and is then introduced to a vacuum iiash tower. I3 where a portion of the lighter fractions are removed through overhead line I4 and/or one or more side stream withdrawals. The final product is then withdrawn as a bottoms product from the ash tower through line I5. The nal asphaltic product comprises a homogeneous Vasphaltic blend of the two combined asphaltic materials.

As an example of the benefits of this invention, reference is made to the accompanying Table I. The rst column of this table indicates typical asphalticv properties obtainable by reduction of a crude oil. The second and third columns of Table I show the results obtainable by the process of this invention in which a reduced crude asphaltc material is blended with a reduced cracked tar` and an oxidized asphalt respectively. It will be observed that columns 2 and 3 embody ythis invention and produce asphalts having substantially better susceptibility factors,` for asphalts `having the same softening point, than obtainable by straight reduction of asphaltic bottoms. 4The asphalts of columns 2 and 3 would be substantially betterthan the `asphalt of column'l for applications such as roofing and road paving due to the lower susceptibility to temperature changes. In the embodiment of the invention illustrated by columns 2 and 3 of Table I, the remaining asphalt properties are substantially the same as those obtained by the conventional reduction process illustrated in column 1.

TABLE I for the production of asphalts. According to this process, two particular asphaltic materials are blended in particular proportions and subjected to at least some reduction. As a result, the original materials combined are converted to the form of a homogeneous asphalt product having Data illustrating the improved susceptibility characteristics of asphalts` produced by the invention, as compared to the conventional reduction process Method oi Producing Composi- Reduction to tion of Feed Stock Grade Reduction to Grade of Blended Feed St k Lagunillas Reduced Crude e Aruba Soft Bitumen b 17o/180 S. P. Oxidized Aspha Specific Gravity at 85 F Flash, C. O. C., Softening Point, F-..

Pen. at32 F Ductility at 77 F I nsol. in 86 Naphtha, Percent SOLinCSz, Percent 99.9 99.8 99.9.

Olienses Test Homogeneous. Homogeneous- Homogeneous. Susceptibility Factor (Pen. at 4.0 3.4 2.8.

C./Pen. 0 0.).

91.0% heavy crude bottoms (homogeneous).

b 165/l75 S. P. reduced cracked tar, 167 S. P., 19 pen. at 77 F., and9 pen. at 32 F.

( heterogeneous).

17o/180 S. P. oxidized asphalt, 176 S. P., 17pen. at 77 F., and 7 pen. at 32 F.

(heterogeneous).

Referring now to the accompanying Table II, further results are illustrated for the blending of an asphaltic reduced crude bottoms with a reduced cracked tar and with an oxidized asphalt. The procedures conducted to obtain the asphalts indicated in the second and. third column of Table II are identied in the table and lembody the process of this invention. Comparing the asphalt inspections of Table II to the iirst column of Table I, it will be observed that in all cases the resulting asphalts had substantially better (lower) susceptibility factors. With reference to the other asphalt properties identified, that isy ash point, ductility, etc., the data indicates the variety in asphaltic properties which can be obtained by varying the nature and proportions of the constituents blended and reduced in accordance with this invention.

TABLE II properties substantially better than obtainable by straight reduction, oxidation, or blending of the feed materials by conventional processing. Again, by varying the proportions and nature of asphaltic materials treated in accordance with this process, a wide range of asphaltic properties may be obtained.

What is claimed is:

1. A process for producing a homogeneous asphalt blend by the combination of two asphalte, one of which is heterogeneous which comprises the sole treating steps of: mixing a first heterogeneous asphalt selected from the class consisting of tars derived by cracking asphaltic crude oils and oxidized asphalts, characterized by a susceptibility factor lower than about 3.3, and a second homogeneous asphalt derived from an asphaltic crude oil by reduction, characterized by Data illustrating the improved ductility and flashpoint characteristics of asphalte produced by the invention as compared to the conventional direct blending process Method ci Producing Composi- Blending to Reduction to Grade of Blended tion of Blend or Feed Stock Grade Feed Stock Percent Lagunillas Red. Crude... 44.0 e 851). Percent Aruba Soft Bitumen v 56.0 Percent Oxidized Asphalt d 15 0 Specific Gravity at 85 F 1.023. Flash, o. o. 0., F 5 595. softening Point, F. 130. Pen. at 77 F 55. Pen. at 32 F 26. Ductility at 77 F 100+. Insol. in 86 Naphtha, Percent. 21.0. Sol. in CS2, Percent.-- 99.8... 99.8.. 99.8. Ohenses 'I est Heterogeneous. Homogeneous. Homogeneous. Susceptlbility Factor (Pen. at 25 2.3 2.6 2.1.

CJPen. at 0 0.).

e 86 S. P. asphalt ux (59% crude bottoms) (homogeneous). b 91% reduced crude bottoms (homogeneous). 16S/175 S. P. reduced cracked tar (heterogeneous).

d l/180 S. P. oxidized asphalt produced by the oxidation of binder C asphalt (heterogeneous).

As brought out herein, the process of this invention is a basically new and versatile process a susceptibility factor higher than about 3.3, said mixture including not more than about 35% of 2,687,989 7' 8 the said rst asphalt and forming a heterogeneous said second asphalt has a susceptibility factor of asphalt composition, and thereafter reducing the about 3.3 to 6. said mixture by removal of at least 3% of the more volatile constituents of the mixture, whereby a References Cited in the file 0f thS patent fn .l homogeneous as halt com ositon i ob- 5 died p p s UNITED STATES PATENTS 2. The process dened by claim 1 in Which the Number Name Date said lst asphalt comprises about 15 to 25% of 2,220,714 Hersberger Nov. 5, 1940 said mixture. 2,317,150 Lovell et al. Apr. 20, 1943 3. The process dened by claim 1 in which the l0

Claims (1)

1. A PROCESS FOR PRODUCING A HOMOGENEOUS ASPHALT BLEND BY THE COMBINATION OF TWO ASPHALTS, ONE OF WHICH IS HETEROGENEOUS WHICH COMPRISES THE SOLE TREATING STEPS OF: MIXING A FIRST HETEROGENEOUS ASPHALT SELECTED FROM THE CLASS CONSISTING OF TARS DERIVED BY CRACKING ASPHALTIC CRUDE OILS AND OXIDIZED ASPHALTS, CHARACTERIZED BY A SUSCEPTIBILITY FACTOR LOWER THAN ABOUT 3.3, AND A SECOND HOMOGENEOUS ASPHALT DERIVED FROM AN ASPHALTIC CRUDE OIL BY REDUCTION, CHARACTERIZED BY A SUSCEPTIBILITY FACTOR HIGHER THAN ABOUT 3.3, SAID MIXTURE INCLUDING NOT MORE THAN ABOUT 35% OF THE SAID FIRST ASPHALT AND FORMING A HETEROGENEOUS ASPHALT COMPOSITION, AND THEREAFTER REDUCING THE SAID MIXTURE BY REMOVAL OF AT LEAST 3% OF THE MORE VOLATILE CONSTITUENTS OF THE MIXTURE, WHEREBY A FINAL HOMOGENEOUS ASPHALT COMPOSITION IS OBTAINED.

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