US2913391A - Integrated process for production of improved asphalt - Google Patents

Description

W. H. HATCH Nov. 17, 1959 Walter H. Hatch Inventor Byw, Attorney INTEGRATED PROCESS FOR PRODUCTION F IMPROVED ASPHALT Walter H. Hatch, Cranford, NJ., assigner to Esso Research and Engineering Company, a corporation of Delaware Application May 26, 1955, Serial No. 511,318

3 Claims. (Cl. 208-40) .present invention, a crude oil is handled in a manner to segregate the desired products comprising a reduced crude fraction, a gas oil fraction which is cracked under conditions to use the overhead from the reaction zone to strip the reduced crude fraction and segregate a bottoms stream from the fractionator comprising cracked and virgin asphaltic constituents. This latter stream is then handled to segregate a high quality asphalt product.

Heretofore in the art asphalts have been produced employing vacuum reduction of the reduced crude bottoms generally from an atmospheric fractionating tower. In accordance with the present invention the feed stream to a vacuum pipe still for the manufacture'of the present high quality asphalts comprises both Virgin and cracked asphalt constituents.

The process of the present invention may be readily understood by reference to the drawing illustrating one embodiment of the same. Referring specifically to the drawing, a crude oil is introduced into distillation zone 1 by means of feed line 2. Temperature and pressure conditions in zone 1 are adjusted to remove overhead by means of line 3 normally gaseous hydrocarbon constituents and light motor fuel components. Heavier hydrocarbon constituents boiling in the motor fuel boiling range are removed from distillation zone 1 by means of line 4 while constituents boiling in the light distillate range as, for example, kerosene, diesel fuel and heating fuel are removed from zone 1 by means of line 5. Typical boiling ranges for the fractions removed from line 3 is up to about 220 F. while the fraction removed by means of line 4 boils in the range from about 220 F. to about 430 F. This fraction, if desired, may be reformed in zone 6. The fraction removed by means of line 5 boils in the range from about 430 F. to about 650 F.

A bottoms fraction boiling above about 650 F. is removed from distillation zone 1 by means of line 7 and introduced into a fractionation zone 8 at a point above the bottom of the zone. The virgin gas oil fraction removed by means of line 5 is introduced into a cracking zone 9 where the fraction may be cracked by Various processes. It is to be understood that cracking zone 9 may comprise one or more stages as, for example, a reaction zone and a regeneration zone if fluid catalytic process is utilized.

The cracking operation conducted in zone 9 may be any desired type employing a catalyst such as modified natural or synthetic clay or gel type catalysts. Examples of these catalysts are montmorillonite clays, silicaalumina, silica-magnesia composites and other conventional cracking catalysts. The process may comprise a continuous or batch operation employing fixed beds, moving beds, uidized, or suspensoid systems. The heat required for cracking may be supplied as preheat of proc atent 'ice essed materials and/or as the sensible heat of exothermically regenerated catalyst or may be supplied in any other conventional manner. The cracking is carried out at temperatures of about 800 F. to 1000 F., and pressures of about atmospheric to 25 p.s.i.g. or higher in a conventional manner.

If the cracking operation should be a uid unit it may be carried out in a conventional manner.

The fluid catalytic cracking operation comprises three sections: cracking, regeneration, and fractionation. The cracking reaction takes place continuously in one reactor,

the spent catalyst being removed continuously for reygeneration in a separate vessel, from which it is returned to the cracking vessel. Continuity of flow of catalyst as well as of oil is thus accomplished, and the characteristic features of fixed-bed designs involving the intermittent shifting of reactors through cracking, purging, and regeneration cycles are eliminated.

Regenerated catalyst is withdrawn from the regenerator and ows by gravity down a standpipe, wherein a sufiiciently high pressure head is built up on the catalyst to allow its injection into the fresh liquid oil stream. The resulting mixture of oil and catalyst ows into the reaction vessel, in which gas velocity is intentionally low, so that a high concentration of catalyst will result. The cracking that takes place results in carbon deposition on the catalyst, requiring regeneration of the catalyst. The cracked product oil vapors are withdrawn from the top of the reactor after passing through cyclone separators to free them of entrained catalyst particles, while the spent catalyst is withdrawn from the bottom of the reactor and is injected into a stream of undiluted air which carries the catalyst into the regeneration vessel. The products of combustion resulting from the regeneration of the catalyst leave the top of this vessel and pass through a series of cyclones where the bulk of the entrained catalyst is recovered. The regenerated catalyst is Withdrawn from the bottom of the vessel to complete its cycle.

Operating temperatures and pressures may vary appreciably depending upon the feed stocks being processed and upon the products desired. Operating temperatures are, for example, in the range from about 800 F. to 1000 F., preferably about 850 F. to 950 F., in the reaction zone. Elevated pressures may be employed, but in general pressures below lbs. per sq. in. gauge are utilized. Pressures generally in the range from 1 to 30 lbs. per sq. in. gauge are preferred. A catalyst holdup corresponding to a space velocity of 1 to 2O weights per hour of feed per weight of catalyst is utilized. A preferred ratio is 2 to 4. Catalyst to oil ratios of about 3 to 10, preferably about 6 to 8 by weight, are used.

The catalytic materials used in the fluidized catalyst cracking operation, in accordance with the present invention, are conventional cracking catalysts. These catalysts are oxides of metals of groups II, III, IV and V of the periodic table. A preferred catalyst comprises silica-alumina wherein the weight percent of the alumina is in the range from about 5 to 20%. Another preferred catalyst comprises silica-magnesium where the weight percent of the magnesia is about 5% to 20%. These catalysts may also contain a third constituent as for example, Th02, W03, MOO, BeO, Bi2O3, CdO, U03, B203, S1102, F6203, V205, MDO, C1203, Cao, T1203, MgO, and Ce203 present in the concentration from 0.05% to 0.5%. The size of the catalyst particles s usually below about 200 microns.

The total cracked products are removed overhead from cracking zone 9 by means of line 10. These products are substantially free of any catalyst particles if a fluid operation is utilized. This stream is introduced into fractionating zone S at a point below the point of introduction of the reduced crude fraction. Under certain .conditions the vapor streams removed from pipe still A-1fby means of lines 3 and 4 may be also introduced into fractionating zone 8 at a point below a point of introduction of the reduced crude fraction. This operation permits a maximum removal of gas oil constituents from the reduced crude fraction which constituents boil below about 1000 F. Fractionating zone 8 is operated to Segregate by means of line 11 hydrocarbon constituents boiling up to about 430 F. which are removed by means .of line 11. A light fuel oil fraction boiling in the range from about 430 F. to 490 F. is removed by means of line 12 while a heavy fuel oil fraction boiling in the range of about 490 F. to 600 F. is removed by means of line 13. A gas oil fraction boiling in the range from about 600 F. to l000 F. is removed by means of line 14 and passed to cracking zone 9 and handled as hereinbefore described.

In accordance with the present invention a heavy bottom stream boiling above about 1000 F. is removed from fractionator 8 by means of line 15 and passed to a vacuurn pipe still 16. Temperature and pressure conditions in zone 16 are adjusted to segregate an asphalt fraction boiling above about 1l00 F. by means of line 17. An overhead fraction comprising constituents boiling below about 1100 F. is removed overhead from zone 16 by means of line 18 and recycled to zone 9.

The invention may be further understood by the following eXarnple illustrating the same: A crude was handled in the manner as described above so as to produce a heavy bottoms stream from fractionator 8 which comprised 72.6 volume percent of a reduced crude and 26.7 percent of a catalytic cycle oil secured from a cracking operation. The remaining 0.7 volume percent comprises reformer tar.

This mixture was fed to a pipe ystill and reduced to 174 penetration at 77 F. bottoms. Inspection results on the asphalt are listed in Table I along with similar data on a 172 penetration asphalt obtained from a sample of the same crude, but without the catalytic fractions.

TABLE I Asphalt quality RESENTING A STRAIGHT RESIDUE AND BOTTOMS FROM A CCLMBINATION UNIT Blend of Reduced Reduced Source Crude Crude Plus Catalytic Fractions Specie gravity at 60 F 1. 024 1 026 Flash (COC), F 655 645 Soitening point, F- 102 104 Pen., 77/100 g./5. 17 174 Pen., 32/200 gJO" 25 27 Pen 1l5l50 g 5"- 300+ 300+ Pen 100/100 ./5" 300+ 300+ Ductility at 77 F., ein. 100+ 100+ Ductility at 39.2 F., om. 32 42 Volatility loss g.,l5 hr./325 F.), percent 0.0 0.0 Pen. at 77 F. on vol. res 143 142 Pen. at 77 F. on vol. res., percent original 83 82 DuctlitsT at 77 F. on vol. ros- 100+ 100+ 112 91. 6 63.3 52. 4 Sulfur (BOMB), percent- 3.96 3.66 Sol. lu C014, percent 99. 9 99. 8 Sol. in CS2 percent 100 100 Insol. in 86 naphtha, percent. 15.1 19. 6 Fixed carbon, percent 14. 76 14. 67 Impact at 40 F., nches 2. 5 4. 0 Oliensis spot test Neg. Pos. Susceptibility indices:

softening pointpen 7 60 Low temperature" 16 Fluldlty 78 68 The data in Table I indicate that the asphalts are substantially equivalent with respect to the ash points, gravities, sulfur contents and solubilities in CS2 and CCLi. However, the blend is superior for paving purposes because it exhibits a better low temperature susceptibility index, greater ductility at 39.2 F., and better resistance to failure by impact.

What is claimed is:

1. Improved process for the production of a high quality asphalt comprising virgin asphaltic constituents and cracked asphaltic constituents which comprises distilling a crude oil in an initial distillation unit to segregate a reduced crude boiling above about 650 F. and a gas oil fraction boiling in the range from about 430 to 650 F.; passing the gas oil fraction to a uid cracking zone wherein the same is subjected to temperature and pressure conditions to produce cracked products; passing said reduced crude fraction and said cracked products to a product fractionation zone which is operated under conditions to segregate a gas oil fraction boiling in the range from about 600 to 1000 F., which is passed to the same uid cracking zone previously mentioned, and a bottoms fraction boiling above about 1000 F. and containing both virgin and cracked constituents; passing said bottoms fraction to a vacuum pipe still and removing overhead from said pipe still constituents boiling below about l100 F.; and segregating as a bottoms product an asphalt comprising cracked asphaltic constituents and virgin asphaltic constituents.

2. Process as defined by claim 1 wherein said fraction removed overhead from said vacuum pipe still is introduced into said cracking zone.

3. Process as deiined by claim 1 wherein the bottoms fraction removed from said product fractionation zone comprises about 20% to 35% of cracked constituents and from to 65% of reduced crude constituents.

References Cited in the le of this patent UNITED STATES PATENTS 2,067,264 Ebberts Ian. 12, 1937 2,107,156 Kuhn et al Feb. 1, 1938 2,136,172 Powell Nov. 8, 1938 2,416,608 Brackenbury Feb. 25, 1947 2,662,051 Pelzer Dec. 8, 1953 2,687,989 Goodwin Aug. 31, 1954 2,691,621 Gagle Oct. 12, 1954 2,733,191 Rupp Jan. 31, 1956 OTHER REFERENCES Goulston: Chemistry and Industry (London), vol. 57 (1948), pp. 375480.

Claims (1)

1. IMPROVED PROCESS FOR THE PRODUCTION OF A HIGH QUALITY ASPHALT COMPRISING VIRGIN ASPHALTIC CONSTITUENTS AND CRACKED ASPHALTIC CONSTITUENTS WHICH COMPRISES DISTILLING A CURDE OIL IN AN INITIAL DISTILLATION UNIT TO SEGREGATE A REDUCED CRUDE BOILING ABOVE ABOUT 650* F. AND A GAS OIL FRACTION BOILING IN THE RANGE FROM ABOUT 430* TO 650* F.; PASSING THE GAS OIL FRACTION TO A FLUID CRACKING ZONE WHEREIN THE SAME IS SUBJECTED TO TEMPERATURE AND PRESSURE CONDITIONS TO PRODUCE CRACKED PRODUCTS; PASSING SAID REDUCED CRUDE FRACTION AND SAID CRACKED PRODUCTS TO A PRODUCT FRACTIONATION ZONE WHICH IS OPERATED UNDER CONDITIONS TO SEGREGATE A GAS OIL FRACTION BOILING IN THE RANGE FROM ABOUT 600* TO 1000* F., WHICH IS PASSED TO THE SAME FLUID CRACKING ZONE PREVIOUSLY MENTIONED, AND A BOTTOMS FRACTION BOILING ABOVE ABOUT 1000* F. AND CONTAINING BOTH VIRGIN AND CRACKED CONSTITUENTS; PASSING SAID BOTTOMS FRACTIONS TO A VACUUM PIPE STILL AND REMOVING OVERHEAD FROM SAID PIPE STILL CONSTITUENTS BOILING BELOW ABOUT 1100* F.; AND SEGREGATING AT A BOTTOMS PRODUCT AN ASPHALT COMPRISING CRACKED ASPHALTIC CONSTITUENTS AND VIRGIN ASPHALTIC CONSTITUENTS.

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