CA1036967A - Process for separating hydrocarbon materials - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
In a continuous process for separating crude oil into two distinct fractions of high definition, crude oil is continuously introduced into a flow path having a portion relatively narrow in cross-section. Heat is supplied to the crude oil along the narrow cross-section portion of the flow path to volatilize one crude oil fraction thereby producing a mixture of a volatilized fraction and a residual liquid fraction. The rate at which the crude oil is introduced into the flow path, the narrow cross-section of the portion of the flow path and the heat supplied effect a high rate of volatilization, a high velocity of the mixture through the narrow cross-section portion of the flow path, and intimate contact between liquid and vapor fractions. After the residual liquid fraction and volatilized fraction mixture is discharged from the flow path, the volatilized fraction is allowed to separate rapidly and become isolated from the residual liquid fraction.

Description

BACKGROUND OF THE INVENTION
This invention relates to the separation of hydrocarbons and, more particularly, to the separation of hydrocarbons through vaporization in a plate s epar ator .
Petroleum, in its unrefined state, is referred to as crude oil. rO
20 obtain commercial products therefrom, the crude oil is separated or fraction-ated by distillation into various hydrocarbon components or "fractions". The fractions are characterized by the number of carbon atoms in each molecule of a particular fraction, the density of the fraction, and the boiling point of the fraction. For classification purposes, the fractions may be designated as follows: (a) straight run gasolines, having boiling points up to about 390F;
(b) middle distillates, including kerosene, heating oils, and diesel fuel, having boiling points from about 340F. to 650F; (c) wide cut gas oils, including waxes, lubricating oils, and feed stock for catalytic cracking to gasoline, having boiling points from about 650F. to 1000F; and (d) residual oils, 30 including asphalts, having boiling points higher than 1000F.
In processing petroleum, crude oil is first desalted and dehydrated, as necessary, and passed through heaters where the temperature is raised to - 1 - .

~ . - : . .. .

- ,' ;, .. :, . . - . .
~ .

' ~036~G7 about 600-650F. The crude oil is thus heated to the point where substan-tially all of the gasolines and middle distillates are in the vapor phase. The crude oil liquid and vapor mixture is then piped to a distillation or fraction-ating tower for "topping", which represents the first step in separating the crude oil into its constituent fractions.
A distillation tower operates basically by the counter-current con-tacting of vapors and liquids to effect separation. The crude oil liquid-vapor feed stock is introduced into the distillation tower approximately one third of the height of the tower from it~ bottom. In the tower, the feed stock vapors 10 separate from the liquid portion of the feed stock and rise toward the upper end of the tower, while the feed stock liquid falls toward the bottom of the tower. Heat is continuously supplied to the base of the tower to insure that the petroleum fractions selected for separation from the liquid portion of the feed stock are continually vaporized and rise toward the upper end of the tower. The temperature inside the distillation tower decreases from bottom to top and therefore only the fractions having relatively low boiling points reach the top of the tower. A series of perforated, disc-like trays extend transversely across the diameter of the tower both above and below the feed stock inlet. By providing a continuous flow of a liquid petroleum fraction 20 over each of the perforated trays, rising feed stock vapors are forced to pass through a liquid layer at each tray.
The combination of decreasing temperature and intimate contact with liquid layers at successively higher levels in the tower causes the feed stock vapors to be entrained in the liquid on the trays at levels in the tower inversely related to the boiling points of the various fractions from which the vapors were produced. The liquid flowing over the trays is then drawn off from the side of the distillation tower at points along its height corresponding to the levels in the tower at which various vaporized fractions from the feed stock have been entrained in the liquid flowing over the traysO The liquid for 30 the trays in the tower may be provided by taking a portion of a liquid fraction drawn off from the tower, cooling the fraction, and then recirculating it over appropriate trays. Such a recirculated liquid fraction is referred to as cold reflux .

103696~7 The liquid-covered trays of the distillation tower effectively prevent the fractions of the feed stock having relatively high boiling points from contaminating fractions having relatively low boiling points. The reverse is not true, however, since at each level in the distillation tower, some vapors which should rise to a higher level in the tower may be entrained in the liquid fraction flowing over the trays. Thus, each of the roughly separated petroleum fractions taken from a topping operation must be pro-cessed further, not only to segregate further the constituent fractions but also to remove completely any contaminating fractions having lower boiling 10 points.
The fractions from a topping operation may have contaminating frac-tions with lower boiling points removed by subjecting the fractions to a blast of stripping vapor, such as steam. Stripping may be accomplished as a separate step or may be included in a further and more precise distillation or fractionation step. In one method of precise fractionation, a feed stock comprising a heated, roughly defined fraction from a topping tower is intro- -~
duced into a second distillation tower in which all feed stock vapors or "overheads" are separated as a single fraction from the higher boiling point liquid residues or "bottom8". In a precise fractionation tower, stripping 20 steam may be applied to the residue at a point below the feed stock inlet.
Alternatively, a portion of the residue may be removed from the tower, reheated in a reboiler and then reintroduced into the lower end of the tower as a stripping vapor.
Although heat alone is theoretically sufficient to effect complete fractionation of a crude oil into its constituent fractions, excessive tempera-tures, for example, in excess of 750F., cause higher boiling point fractions to crack or break down into lower molecular weight, lower boiling point fractions, instead of vaporizing. To avoid cracking, for example, where one of the end products is to be an asphalt fraction, it may be necessary to carry 30 out the fractionation in a vacuum distillation tower. By applying a partial vacuum to the tower, the effective boiling points of the various fractions in the crude oil are reduced and the temperature in the tower can be maintained ~()3696q below the critical cr~cking temperature, while still ensuring that some relatively high boiling point fractions are vaporized and separated from the liquid portion of the feed stock. Steam may be added to the feed stock in a vacuum distillation tower to further reduce the boiling points of the various fractions by a partial pressure effect. Since a part of the low pressure maintained in the vacuum distillation tower is produced by the steam, the effective pressure of the feed stock is less than the total pressure in the distillation tower. If steam is used in a vacuum distillation tower, however, a larger tower is required to obtain a given throughput of feed stock.
At present, the most highly desired fraction in a crude oil is gasoline, which is only available in certain limited percentages in any given crude oil.
Additional gasoline can be obtained from crude oil, however, by cracking higher molecular weight, higher boiling point fractions. Although it is possible to crack a reduced crude oil (i. e. crude oil from which some lower boiling point fractions have been removed) simply by heating, as noted above, a more efficient and economical method is to remove the highest boiling point fractions, such as the asphalt fractions, from the reduced crude oil before cracking. Such separation or fractionation of various relatively high boiling point fractions is generally done by a vacuum flash process.
ZO In a vacuum flash operation, the residue or reduced crude oil from a topping operation is first heated and then introduced into a flash drum or tower that is maintained at an extremely low absolute pressure. The tempera-ture of the reduced crude oil feed stock and the pressure in the flash drum are correlated so that when the feed stock is introduced or flashed into the drum, the effective boiling points of selected petroleum fractions present in the feed stock are reduced below the temperature of the feed stock and the fractions desired for cracking or other purposes immediately vaporize. The higher boiling point fractions remain in a liquid state and fall to the bottom of the flash drum. Care is taken to avoid vaporization of the feed stock in 30 the heating furnace because the reduced crude oil feed stock has a relatively high viscosity and further concentration of the feed stock is likely to result in a build up of residue on the heating surfaces in the furnace, increasing maintenance costs and reducing efficiency.

3~3696~
While the foregoing methods are effective with regard to separating out the relatively high boiling point fractions in a crude oil, the methods are also expensive. Beyond the initial installation cost of a basic distillation tower operating at atmospheric pressure, for example, the major cost of such a tower is represented by the cost of heating the feed stock. If stripping steam is used in conjunction with the distillation tower to improve its effectiveness, additional heating costs are incurred for heating the steam and costs are incurred for separating the water vapor from the various fractions produced in the tower. If a partial vacuum is applied to the distillation tower, 10 additional equipment must be supplied to evacuate the tower. Finally, if a vacuum flash unit is used, the initial cost is approximately doubled because the cost of such a unit is substantially greater than the cost of a conventional distillation tower. Also, evacuating units are commonly steam ejectors, which remove gases from a chamber by entraining the gases in high velocity jets of steam. Thus, fractionation methods utilizing vacuum chambers generally require additional heating facilities to produce the steam necessary to operate the evacuation units.
While the above discussion has focused on the fractionation of petroleum in the form of virgin crude oil, other petroleum stocks are of some com-20 merical importance at present and each involves somewhat different refiningproblems than the problems encountered with virgin crude oilsO
Reconstituted crude oils generally comprise asphalt or some other high density, high boiling point petroleum fraction that has been cut or diluted with a low density, low boiling point petroleum fraction to make a pumpable or otherwise transportable material. Reconstituted crude oils are generally encountered in situations where crude oil taken from a well is refined at a plant in the general vicinity of the wellO Since many oil wells are at locations remote from the areas in which the various refined petroleum fractions are to be consumed, the fractions must often be shipped or pipelined to their 30 eventual destinations. When the fraction being transported has a high vis-cosity, such as asphalt, transportation becomes a substantial problem.

1~33*~Çi`7 While an asphaltic petroleum fraction may be transported with special equip-ment or by the continuous application of heat to maintain the fraction at a low viscosity, it is economically attractive to dilute the fraction with another petroleum fraction, preferably a ready-for-sale fraction of economic value in the same area to which the asphalt is being shipped. When the reconstituted crude oil arrives at its destination, therefore, it must be processed to obtain not only the asphalt fraction but also the precise diluent fraction at its original specifications, without substantial added costs.
Previous attempts to utilize reconstituted crude oils to transport 10 asphalt fractions have not been successful because the reconstituted crudes could not be separated into specification asphalt and the precise diluent fraction at its original specifications. As an example, a major manufacturer in California produced a reconstituted crude oil from 85-100 penetration asphalt and stove oil (approximately 38 API, IBP at 400F., 50% at 510F., End Point at 610F. ). The reconstituted crude was shipped to Washington, among other destinations, where it was refined. The refining equipment utiliz;ed was essentially a pipe still and a vacuum column. Specification asphalt was produced but the overhead material included too large a quantity of high molecular weight fractions to be saleable as stove oil. A small 20 quantity of the overhead material was sold as usable only as blending stock with other petroleum products. The remainder of the overhead material was returned to refineries of the manufacturer and added to the refinery feed stock or used as a cutter for asphalt. While a fractionating tower might have been used effectively to process the reconstituted crudes, the expense of a tower is not justified for reconstituted crudes having a relatively low propor-tion (i.e. about 25%) of diluent.
Junk oil, as its name implies, comprises petroleum wastes from various sources. The junk oil may consist of residues from a refinery directed mainly toward the production of gasoline fractions and cracking feed 30 stocks, used automotive lubricating oils, and similar materials. It also may include some water mixed with the petroleum products as an emulsion. An example of junk oil that includes a water-petroleum emulsion is ship' s diesel ~03~9~ 7 and/or bunker uel contan~inated by water co-ndensate. Such contaminated fuel was once simply dumped overboard, but present maritime regulations prohibit dumping in many areas. Oily emulsions are also formed in tanker ballast, the thermal production of heavy crudes, and pipeline operations where an emulsion is intentionally produced to facilitate pipelining.
Processors of junk oil are typically paid approximately two cents per gallon to dispose of the oil. The junk oil is first treated with chemicals to break the water-oil emulsion and then processed into various petroleum fractions. Fractions produced in small quantities, such as gasoline, are 10 often burned, while the fractions produced in larger quantities can be sold as recovered lubricating oils and/or cutter for asphalt, for example. Pro-cessing costs, including the price paid to the processor to dispose of the oil, run from approximately eight to ten cents per gallon of saleable end product.
The price received for the saleable end products is about fifteen cents per gallon .
SUMMARY OF THE INVENTION
The present invention is a process unique to the field of petroleum refining for the accurate, efficient, and economic separation of a petroleum feed stock, particularly a feed stock having a high percentage of relatively 20 high boiling point fractions, into two distinct fractions of high definition.
In the inventive process, petroleum is continuously fed into a flow path. ~t least a portion of the flow path has a relatively narrow cross-section to form a constricted passageway and is elongated in the direction transverse to the flow of petroleum. With the petroleum passing through the flow path, heat is supplied at least along the constricted passageway to volatilize the lower boiling fractions of the petroleum within the constricted passageway.
As the mixture of liquid petroleum residue and released vapors continues to pass through the constricted passageway, additional heat is being supplied.
The initial rate of flow at which the liquid petroleum is introduced into the 30 flow path, the constricted passageway, and the heat supplied to volatilize the lower boiling fractions of the petroleum effect a high rate of progressive vapor release (rectification) and a high velocity of the mixture through the ;9~7 constricted passageway. I'he mixture of the liquid petroleum residue and released vapors is then discharged from the flow path and the released vapors are allowed to separate rapidly and become isolated from the concentrated liquid petroleum residue.
The inventive process is to be contrasted with the vacuum flash process in which the liquid hydrocarbon feed stock is passed through a heat-ing zone but vaporization is prevented until the feed stock is introduced into the flash drum. A relatively high absolute pressure is maintained in the heating zone in the vacuum flash process primarily to provide a substantial 10 pressure drop between the heating zone and the flash drum and thereby facilitate a rapid and sharply defined separation of the feed stock into a con-centrated liquid and a vaporO The pressure in the heating zone also prevents a portion of the feed stock frorrl vaporizing and leaving the concentrated liquid, or a portion thereof, adhering to the heating surfaces. Finally, since vaporization of the feed stock occurs entirely within the flash drum, the drum must be relatively large and fabricated of heavy, high strength materials to accommodate the substantial increase in volume of the feed stock and with-stand the external pressures tending to implode the drumO
The inventive process, by causing vaporization of a portion of the feed 20 stock without separation of the concentrated liquid and released vapors within a heating zone, accelerates the flow of feed stock through the heating zone due to the expansion of the released vapors and, at the same time, improves the flow characteristics of the feed stock due to the reduced viscosity of the liquid-vapor mixture. The continuous and progressive release of vapors from the feed stock also represents a continuous conversion of sensible heat to latent heat of vaporization, which has the effect of continually reducing the temperature of the liquid-vapor mixture and maintaining an efficient, high temperature differential between the liquid-vapor mixture and the heating surfaces. Moreover, and in contrast to the vacuum flash technique, the 30 continuous release and rapid expansion of the vapors continuously reduces the pressure within the heating zone, making it possible to maintain a very low absolute pressure throughout the process flow path. Maintenance of a low ~03 ;9~7 absolute pressure is also facilitated by the relatively small size of the separator following the heating ~one. Since a substantial portion of the increase in volume of the feed stock occurs in the heating zone, the separator can be made significantly smaller than a flash drum operating at the same absolute pressure.
In comparison to distillation techniques, the present process permits separation of lower boiling point petroleum fractions from residual asphaltic fractions without the necessity for a liquid-vapor countercurrent contact operation and consequently the need for massive distillation towers. Such 10 distillation towers may range up to 200 feet in height and may present sub-stantial engineering problems to provide for their support. In addition, distillation towers of any substantial height tend to project above and clash with surrounding ground features. In the present era of concern for the environment, large distillation towers represent a highly visible type of environmental "pollution" which may increase local opposition to locating refining facilities in areas conveniently close to an adequate supply of labor, electricity or othernecessary resourcesO Typical apparatus for practicing the inventive process is less than twenty feet high and therefore presents a substantially less objectionable image than a distillation tower. The preferred 20 apparatus for practicing the invention process is shown in the drawings for the present application, but the apparatus shown in my previously issued UOS.
Patents Nos. 3,073,380 and 3,469,617 and in Canadian Patent No . 926~291s issued to Ruths, may be advantageously used with some modification to practice the inventive process.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding Or the invention, reference may be made to the following description of exemplary apparatus for practicing the present invention, taken in conjunction with the figures of the accompanying drawings, in which:
Fig. 1 is a diagrammatic view of a system arranged to practice the invention;

1~3696'7 Fig. 2 iB a perspective view of one type lamella unit which may be used in the system of l~ ig. l;
Fig. 3 is a side view of the plates of the lamella unit shown in Fig. 2;
Fig. 4 is an enlarged side view, partly broken away, of a portion of the plates shown in Fig. 3;
Fig. 5 is a partial sectional view of the plates of Fig, 3, taken along view line 5-5;
Fig. 6 is a second partial sectional view of the plates of Fig. 3, taken along view line 6-6; and Fig. 7 is a third partial sectional view of the plates of Fig. 3, taken along view line 7-7.
DESCRIPTION OF A REFERRED EMBODIMENT
Fig. 1 illustrates a typical system arranged to practice the inventive process using, for example, a feed stock of reconstituted crude oil com-prizing a specification asphalt diluted with a specification diesel fuel. While the feed stock should generally have all contaminating water removed before being introduced into the system, the presence of water does not inhibit efficient operation of the system and, in fact, water may be advantageously added to especially viscous or concentrated feed stock to improve the release 20 of vapors described hereinafter.
Thus, in the Fig. 1 system, a reconstituted crude oil is supplied through a delivery line 13 to a pump 14. The pump 14 pumps the crude oil along a line 15 to a heat exchanger 16 wherein the crude oil is heated by the separated asphait fractions (described hereinafter) emerging from the system. A pressure control valve 18 in the line 14 insures that the crude oil is delivered to the system at the proper pressure. In addition, a pressure gage 19 provides a visual indication of the pressure in the line 14. In the Fig. 1 schematic, all the pressure gages in thc system have been designated with the letter "P" and the temperature gages have been designated with the 30 letter "T". In addition, the gages are identified with separate numbers.
After passing through the heat exchanger 16, the crude oil passes along a line 20 to a second heat exchanger 21, where the feed stock is further ~036967 heated by a separated diesel fuel fraction (described hereinafter) from the system. A temperature gage Z2 i9 coupled into the line Z0 to monitor and display the temperature of the crude oil immediately after the oil emerges from the heat exchanger 16. From the heat exchanger 21, the feed stock flOws through a feed line 23, past a temperature gage 24, into a preheater unit 25. Both the preheater unit 25 and the succeeding lamella unit 26 are generally similar in construction, and are described below with particular reference to the lamella unit, as shown in Figs. 2-7.
The lamella unit 26 comprises a series of parallel and closely spaced 10 plates or lamellae 28. Each of the plates 28 is roughly octagonal in shape, and includes two elongated sides 30. Alternate sides of the plates 28, including the elongated sides 30, are sealed completely, for example, by welding, to prevent fluid loss. The four remaining sides of the plates 28 are connected to cap members 32a-32d, which are in turn connected to lines 48, 60, 52 and 43, respectively.
As can be seen in Figs. 2-7, the plates 28 are preferably formed of - metal and have dimpled or waffle-like surfaces. Referring especially to Figs. 3 and 4, the plates 28 are fitted together so that each pair of adjacent plates 28 defines between the plates a checkerboard-like arrangement of 20 open spaces and contact points 33. The overall effect of the plate arrange-ment is to provide, between each pair of adjacent plates 28, a series of interconnected passages 34 oriented at right angles to each other. Thus, fluids may flow through the passages 34 in a generally diagonal direction across the plates 28, as illustrated in Fig. 4.
In the illustrated apparatus, four plates 28a-28d provide three separate strata of fluid passages 34a-34c within the lamella unit 26. A
heating fluid, such as hot oil, is introduced through the cap member 32, as shown in Figs. 3 and 6, into the outer fluid passages 34a and 34c. The heating fluid flows diagonally across and between the plates 28a, 28b and 28c, 30 28d to the opposite cap member 32c, where the heating fluid exits from the lamella unit 26. The center fluidpassages 34b are sealed, for example, by welding, at cap members 32a and 32c, to keep the heating fluid separate ~0~
from the feed stock. Simultaneously with the flow of heating fluid, reconsti-tuted crude oil is introduced through thc cap member 32d, as shown in Fig. 3, into the center fluid passages 34b. The crude oil flows diagonally across and between the plates 28b, 28c to the opposite cap member 32b, where the feed stock leaves the lamella unit 26. Fig, 7 illustrates how the outer fluid passages 34a and 34c are sealed at the cap members 32b and 32d to separate the heating fluid and the reconstituted crude oilO
The close spacing of the plates 28 permits the crude oil to come into intimate contact with the plates 28b and 28c heated by the heating fluid and 10 provide the continuous heating and vapor release required by this process.
The relatively great lateral dimensions of the plates 28 and thus the fluid passages 34, in comparison with the spacing of the plates, permits the vapors released from the reconstituted crude oil to expand rapidly, thereby increas-ing the flow of crude oil through the lamella unit 26. The configuration and spacing of the plates Z8 also maintains the concentrated liquid and released vapors from the reconstituted crude oil in a generally homogeneous mixture.
The capacity of the lamella unit 26, and likewise the preheater unit 25, may be increased to any extent by providing additional pairs of closely spaced plates 28. Each new pair of plates 28, when placed beside the existing plates 20 28, defines two new strata of fluid passages 34 through which feed stock and heating fluid, respectively, may be passed. Such an increase in the capacity of the lamella unit 26 or the preheater unit 25 would require a corresponding increase in the capacity of related apparatus in the system.
The constant vaporization taking place within the lamella unit 26 and the pressure developed by pumping the heating fluid between the lamella plates 28 requires reinforcement of the plates 280 Fig. 2 illustrates rein-forcing structure utilizing aligned pairs of channel members 35 that extend across the width of the plates 28 and overlap the ends of the plates 28.
Arranged back-to-back and spaced slightly apart, each pair of the channel 30 members 35 receive an elongated rod 36 between then at each end. The rod extends between the channel members 35 of one pair on one side of the lamella plates 28, across the four plates 28a-d, and then between the channel members ~03~i9~
35 of a second pair of channel members on the opposite side of the lamella plates 28. The outer flanges of the channel members 35 of each pair are interconnected by cover plates 37 through which the rods 36 pass. A washer 38 and a nut 39 are placed over each end of each rod. The nuts 39 are tightened against the cover plates 37 and the flanges of the channel members 35. Longer cover plates 37a may be used to interconnect adjacent pairs of channel member s 35.
A single pair of vertically oriented channel members 35a are provided on each side of the plates 28 between the cap members 32a and 3Zb and be-10 tween the cap members 32c and 32d. One end of each vertically orientedchannel member 35a is welded to an adjacent horizontally oriented channel member 35 and the other end is connected to the ends of the adjacent vertically oriented channel members 35a with elongated rods 36a, as described above. A metal angle 40 extends along each joint between the cap members 32a-d and the lamella plates 28. The angle 40 is welded at its ends to a vertically oriented channel member 35a and a horizontally oriented channel member 35, respectively. Four upright I-beams 41 mounted on a metal base plate 42 support the lamella unit 26.
As noted above, the preheater unit 25 is generally similar to the 20 lamella unit 26, except that the plates 28 for the lamella unit Z6 have generally larger dimensions. In addition, no vaporization of the feed stock should occur in the preheater unit 25. The preheater unit 25 and the lamella unit 26 are interconnected by a feed stock delivery line 43, in which a tem-perature gage 44 and a pressure gage 46 monitor the reconstituted crude oil'is temperature and pressure, respectively. Stripping steam may be introduced into the delivery line 43 through an optional steam line 47 adjacent the lamella unit 26. The stripping steam strips the lower boiling point fraction (diesel fuel) from the reconstituted crude oil in the lamella unit 26 to supplement the normal volatilization occurring within the lamella unit. A similar stripping 30 effect may be achieved by adding water to the feed stock or leaving contaminat-ing water in the feed stock. The water is vaporized in the system to produce str ipping steam .

~3696q The heating fluid for both the lamella unit 2h and the preheater unit 25 i9 delivered through a single delivery line 48 into which a temperature gage 50 is connected. The heating fluid, such as hot oil, first passes through the lamella unit 26 and then is carried by a line 52 to the preheater unit 25. A
temperature gage 54 monitors the temperature of the heating fluid in the line 520 After passing through the preheater unit Z5, the heating fluid is returned to a heating furnace (not shown) through a line 56, in which the fluid tempera-ture is monitored by a temperature gage 58.
After passing through the lamella unit 26, the reconstituted crude oil, 10 now a mixture of concentrated liquid (asphalt) and released vapors (diesel fuel), is taken by a delivery line 60 to a separator 62. The temperature and pressure of the mixture in the line 60 are monitored by a temperature gage 63 and a pressure gage 64, respectively. Although the delivery line 60 has been illustrated as being relatively long for convenience and clarity, it should preferably be as short as possible. Excessive length of the delivery line 60 has been shown to affect adversely the inventive process. The reason for the adverse effect is not definitely known, but it may be that the continuous application of heat to the liquid-vapor mixture in the lamella unit 26 keeps the vapor at a different temperature than the liquid. The temperature differential 20 may account for the rapid separation and high throughput observed for the inventive process in comparison with the vacuum flash process, as set forth in the Examples following the description of the system of Fig. lo The asphalt and released diesel vapors in the mixture are allowed to separate rapidly in the separator 62, which is maintained at less than atmos-pheric pressure, so that the vapors rise to the top of the separator 62 and are taken away through the overhead line 65 and the residual asphalt falls to the bottom of the separator 62 and is removed through the bottoms line 660 A
temperature gage 67 monitors the temperature of the residue accumulated in the separator 62. As can be seen in Fig. 1, steam may be supplied through 30 optional steam lines 68 to provide a stripping action to the concentrated liquid from the mixture as the liquid falls down through the separator 62. Similarly, a vaned tuyere 70 may be provided at the upper end of the separator 62 to separate centrifugally any liquid that may be entrained in the rising vapors.

103~967 The asphaltic residue from the separator 62 is carried through the line 66 into a pump 72, which pumps the asphalt through a line 74 to a level control valve 76. The level control valve 76 regulates the flow of asphalt from the pump 72 so that the asphalt accumulated in the separator 62 is maintained at an appropriate depth, between two level monitoring lines 78.
From the level control valve 76, the asphalt is conducted by a line 80 to one of two valves 82 and 84. If the valve 82 is opened, the asphalt is removed from the system through an outlet line 86. On the other hand, if the valve 8Z
is closed or if it is not open sufficiently to accept the full volume of flow from 10 the line 80, the asphalt may pass through the valve 84 into the heat exchanger 16. For economical use of heat energy within the system, the asphalt should preferably flow through the valve 84 into the heat exchanger 16 to preheat the incoming reconstituted crude oil. After passing through the heat exchanger 16, the asphalt is removed from the system through an outlet line 88.
At the top of the separator 62, the released diesel vapors or overheads are withdrawn under a vacuum from the separator 62 through the overhead line 65. The vacuum is provided by a steam ejector 90. A temperature gage 92 monitors the temperature of the vapors in the overhead line 62 immediately after separation. The overhead line 65 carries the overheads to the heat 20 exchanger 21, where the heat in the overheads is used to preheat the re-constituted crude oil. A temperature gage 94 monitors the temperature of the overheads in the line 64 immediately prior to their application to the heat exchanger 21. A line 96, monitored by a temperature gage 98, transports the overheads to a condensor 100 where the overheads are cooled with water supplied from a suitable source to a temperature at which they condense into a liquid. The liquid condensate produced in the condenser 100 flows into a receiver 102 which is connected by an exhaust line 104 to the steam ejector 90. The pressure in the receiver 102 is monitored by a pressure gage 106.
Condensate flows out of the receiver 102 through an outlet line 108 30 into a condensate pump 110. The pump 110 pumps the condensate through a line 112 to a level control valve 114. The level control valve 114 controls the flow of condensate through it so that an adequate depth of condensate is ~03696!7 maintained in the receiver 102. After passing through the level control valve 114, the condensate is withdrawn from the system through an exit line 116.
I'he production rate for the above de~scribed system can be increased, where the feed stock is a reconstituted crude oil, by operating the system to produce specification asphalt only and varying the quality of the cutting fraction as produced. If the cutting fraction must be produced to original specifications, a small rectifying section may be connected into the overhead line 65 to accomplish this result without affecting the production rate.
The system shown in Fig. 1 has been described as operating at less 10 than atmospheric pressure. Nonetheless, the system may be operated at a positive pressure where the feed stock being processed and the fractions to be produced permit. The capability of being practiced under either positive or negative pressure to produce a wide range of petroleum fractions demon-strates the greater versatility of the inventive process in comparison with both the vacuum flash and conventional distillation processes which are directed primarily to refining out only selected ranges of petroleum fractions from a given feed stock.
A further advantage of the inventive process is its capability of pro-ducing commercially significant volumes of various end products while having 20 a relatively small volume of feed stock in process at any one time. The small in-process volumes promote quick and easily effected start-ups, shut downs, and responses to changes in operating conditions.
High heat transfer coefficients are achieved by the high velocity two phase flow and the continuous vaporization of feed stock according to the process, which permit the use of lower temperature heating fluids than would be required in a flash process and, consequently, reduce emissions from associated heating facilitiesO The constant vaporization of feed stock also reduces the load on vacuum producing equipment, when the process is prac-ticed at less than atmospheric pressure. The constant vaporization of feed 30 stock and the consequent high flow rate through a heating zone in apparatus for practicing the inventive process further result in an unexpectedly high throughput for any given apparatus. The throughput is unexpectedly high as 10369~7 compared with the vacuum flash process, which can be practiced with generally similar apparatus.
Overall, the inventive process permits the efficient separation of a wide range of petroleum feed stocks into selected constituent fractions.
Successive passes through particular apparatus or the use of apparatus in series also enables the separation of a feed stock into more than two fractions.
For example, junk oil may be processed by an initial pass through apparatus, such as described above, to separate out water and low boiling point fractions, such as gasoline. The low boiling point fractions are then burned and the 10 liquid residue is filtered to remove carbon, metal pieces and similar insol-uble solid contaminants. A second pass through the apparatus produces an overhead suitable for sale as recovered lubricating oils, for example, while the residue is suitable as a cutter for asphalt. Using the residue as an asphalt cutter may also eliminate any need to filter the junk oil as the solid contaminants can be 'rburied" in the asphalt. The low cost of operating the apparatus, together with the elimination of the need for emulsion-breaking chemicals, presents the possibility of a four to six cent per gallon cost reduction, as compared to other junk oil processesO The first pass through the apparatus, as described above for processing junk oil, may be used 20 alone to reclaim contaminated ship's diesel fuel. By providing a scaled-down version of the apparatus in a ship's boiler room, for example, the contaminated fuel might even be reclaimed on board the shipo The high efficiency and versatility provided by the inventive process are illustrated by the following examples.

A reconstituted crude oil, comprising 80 percent Wilmington 80 penetration asphalt diluted with 20 percent No. 2 diesel fuel, was used to compare the inventive process with the vacuum flash process. Apparatus generally similar to that shown in Fig. 1 was used to produce the data 30 tabulated below.
In practicing the inventive process, the reconstituted crude oil was delivered to the lamella unit through a one-quarter inch diameter line. A

~0;~696~7 one and one-half inch diameter line was used at the outlet of the lamella unit.
To adapt the apparatus so as to simulate the vacuum flash process, a one-quarter inch diameter orifice plate was inserted in the outlet line from the lamella unit. The orifice was intended effectively to inhibit or prevent the release of vapors from the feed stock between the plates of the lamella unit and thereby cause the unit to act simply as heat exchanger. Care was taken to maintain the same pressure in the separator and the receiver in both trials .

Inventive Vacuum Flash Process Process Feed Rate (g . pO m. ) 0 . 9 . 69 Initial Heating Oil Temperature 534F. 545F.

Temperature of Feed Stock at Lamella Unit Inlet 325F. 330F.

Temperature of Feed Stock at Lamella Unit Outlet 484F. 500F.

Pressure at Lamella Unit Inlet 20" Hg 3" Hg Vacuum Vacuum Pressure at Lamella Unit Outlet 28.4" Hg 8" Hg Vacuum Vacuum Pressure in Receiver 28. 6" Hg 28. 6" Hg Vacuum Vacuum 20 Overheads:
API Gravity 32 . 2 32 . 0 Temperature 464F. 436F.
Initial Boiling Point 444Fo 442F.
50% 542F. 536F.
End Point 688Fo 668F.
Color Straw Dark Brown Bottoms:
Temperatur e 46 0 F . 422F .
Flash Point 430F. 400F.

Penetration 86 Soft ( No penetration) 9~7 As the above data indicates, specification asphalt could not be made with the vacuum flash process, despite a 23 percent reduction in the input feed rate. A further trial was run on the reconstituted crude feed stock with the temperature of the heating oil raised to 580Fo As can be seen from the data below, the flash point of the asphalt produced is commercially inadequate.
The overheads contained asphalt fractions, as indicated by their color, and showed a high end point and poor separation.
Feed Rate (g . p. m. ) 0O 69 Initial Heating Oil Temperature 580F.
Temperature at Lamella Unit Outlet 563F.
Overheads Temperatur e 462 F .
Bottoms Temperature 434F.
Overheads:
API Gravity 31.1 Initial Boiling Point 442F.
50~0 540F.
End Point 698Fo Color Dark Brown Bottoms:
Flash Point 415F.
Penetration 115 Trials similar to the trials of Example 1 were run on a reduced Venezuelan asphalt crude oil with the following results:
Inventive Vacuum Flash Process Process Feed Rate (g.p.m.) 0.61 0.49 Initial Heating Oil Temperature 580F. 580F.
Temperature at Lamella Unit Inlet 323F. 320F.
30 Temperature at Lamella Unit Outlet 553F. 522F.
Pressure at Lamella Unit Inlet 21~5" Hg 7.4" Hg Vacuum Vacuum ~036~6t7 Inventive ~acuum Flash Process Process Pressure at Lamella Unit Outlet 28.6" Hg 11.0" Hg Vacuum Vacuum Pressure in Receiver 28.6" Hg 28.6" Hg Vacuum Vacuum Overheads:
API Gravity 27.6 28.6 Temperature 528F. 476F, Initial Boiling Point 460F. 470F.
50% 570F. 550F.
End Point 640F . (79 %) 640F . (85 %) Color Clear Green Muddy Brown Bottoms:
Temperature 526F. 474F.
Flash Point 500F. 435F.
Penetration 160 Soft (No penetra-tion) 20 Despite increasing the heating oil temperature, an acceptable asphalt product was not produced under these conditions.

The ability to reproduce accurately, using the inventive process, the fractions comprising a reconstituted crude oil is demonstrated by the follow-ing data from a trial run on a reconstituted crude oil without stripping steam.
The reference numerals preceding the various temperatures and pressures refer to the various gages indicated on the flow diagram shown in Fig. 1.
Feed Stock: 75% 85 Penetration, 435F. Flash Asphalt 25% 32.45 API NoO 2 Diesel 30 Feed Rate: 4.8 G.P.M. (165 Barrels/day approximately) Temperature Ga~e T22 196Fo T24 274F.
T44 374F.
T63 492F.

10369~7 Tem~erature Ga~e T67 464F.
T9Z 456F, T94 414F`.
T98 234F.
T50 512F .
T54 509F.
T58 505F.
Pressure Ga~e 10 P19 6 psig P46 15" Hg Vacuum P64 27 1/2" Hg Vacuum P106 28+" Hg Vacuum Overheads:
Production Rate = 1.39 g . pO m .
DistillationF. Diluent Overhead Initial Boiling Point 4Z1F. 422F.
10% 469F. 474F.
20% 488F. 496F.
30% 506F. 512F.
40% 520F. 526F.
50% 533F. 538F.
60% 547F . 551F.
70% 559F. 564F.
80% 577F . 581F .
90% 603F. 610F.
95% 638F. 648F.
End Point 677F. 669F.
Recovery (%) 98.0 97.75 30 Residue (%) 2.0 2.25 Loss (%) 0 0 API Gravity @ 60F. 32.45 32.2 Bottoms: 103696'7 Production Rate 3.4 g.p.m.
Penetr ation 86 Flash Point 430F.

The following data demonstrate the effect on the fraction~ produced of varying the feed rate to a particular apparatus for practicing the inventive process. Approximately 4% stripping steam was used. As in Example 3, the gage numbers relate to the gages shown schematically in Fig. 1 lQ Feed Stock: 80~o 100 Penetration Asphalt 20% 32.4 API Gravity Diesel Fuel Trial 1 Trial 2 Feed Rate: 10.6 g.p.m. 8.9 g.p.m.
(360 barrels/day) (300 barrels/day) Temperature Ga~e T22 220C'F . 218F .
T24 260F. 260F.
T44 324F. 323F.
T63 457F. 466F.
20 T67 436F. 439F.
T92 428F. 430Fo T94 408F. 410Fo T98 252F. 248Fo T50 500Fo 500F.
T54 498F. 498F.
T58 490F. 490F.
Pressure Ga~e P19 12 psig 12 psig P46 13" Hg Vacuum 13" Hg Vacuum 30 P64 21" Hg Vacuum 21" Hg Vacuum P106 28" Hg Vacuum 28" Hg Vacuum .

~ 03Y~ 7 Overheads -Trial 1 Trial 2 API Gravity 3Z.7 32.1 Distillation Initial Boiling Point 430F. 430F.
10% 470F. 472F.
Z0% 486F. 488F.
30% 500F. 506F.
40% 514F. 5Z0F.
50% 528F. 532F.
60% 540F. 546F.
70% 552F. 558F, 80% 568F. 574F.
90% 592F. 598F.
95 % 618F . 628F .
End Point 656F. 662F.
Recovery ( %) 98.5 98 O 0 Residue (%) lo 5 2.0 Loss (%) 0 0 20 Bottoms:
Penetration 105 85 Flash Point 450Fo 450F.

The following data illustrate the variations produced in the fractions derived from a particular feed stock using the inventive process by varying the temperature to which the feed stock is heated in the lamella unitO The temperature given for each of the three trials was taken at gage 4, shown in Fig. 1.
Feed Stock: AproxO 75% 120 Penetration Asphalt 25% 34 API No. 2 Diesel Feed Rate: 8-10 g.p.m.

1()369~7 Trial 1 Trial 2 Trial 3 Temperature 435F. 492F. 550F.
Bottoms ~Penetration~ 210 120 30 Overheads (API Gravity) 35.5 33 - 5 31.2 The feasibility of utilizing the inventive process to recycle junk oil i9 demonstrated by the results obtained from a single pass of a sample of junk oil, comprising used motor oil and lubricating grease, through the apparatus illustrated schematically in Figo 1. The single pass gave 75% of 10 good quality overheads, 10% of 13.5 API gravity bottoms and 15% water.
The bottoms may be used to cut asphalts and thereby marketed effectively at asphalt prices. The water represents the only remaining disposal problem.
The data presented above in Examples 4 and 5 illustrate the versatility of the inventive process in that a controlled variation of either or both the feed rate and the operating temperature for the process produces significant differences in the products from the process. The data for Examples 1 and 2 demonstrate the beneficial reduction in absolute pressure in the exemplary apparatus, resulting from the inventive process. The data similarly demonstrate an unexpected increased throughput, with satisfactory end 20 products, achieved by the inventive process, in comparison with the simulated vacuum flash process. The higher flash points of the bottoms also indicate a more pronounced separation between the bottoms and the overheads, in the inventive process.
It should further be noted that in all trials, the asphaltic bottoms produced using the inventive process exhibited very high ductility in compari-son with penetration, and a high penetration with respect to the vacuum flash process. For example, from a Tijuana Pesada crude oil having an API
gravity at 60F. of 11.5, the inventive process produced overheads having an API gravity at 60F. of 22.8 and bottoms, after 35 percent of the feed 30 stock had been removed as overheads, having a penetration at 77F. of 90 and a ductility at 77F. of over 200. The relatively high ductility of the ~03~j9~7 bottoms from the inventive process nlay bc t:he result of the low kemperature at which penetration asphalts can be made using inventive process, in com-parison with other processes.
It will be understood that the above-described process and apparatus for practicing the process are merely exemplary and that those skilled in the art rnay make many variations and modifications in the exemplary process and apparatus without departing from the spirit and scope of the inventionO
All such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims (22)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A continuous process for separating at least one hydrocarbon fraction of high definition out of a liquid hydro-carbon material, which comprises continuously introducing the liquid hydrocarbon material into a flow path of which a portion in cross-section transverse to the flow of the liquid hydrocarbon material therethrough is elongated in one direction and relatively narrow in a generally perpendicular direction;
passing the liquid hydrocarbon material through the flow path while supplying heat at least along the portion of the flow path to cause the volatilization of part of the liquid hydro-carbon material in the portion of the flow path; continuing to pass a mixture of concentrated liquid hydrocarbon material and vapors released therefrom through the portion of the flow path while continuing to supply heat thereto, thereby to effect a high rate of vapor release and impart a high velocity to the mixture as it passes through the portion of the flow path;
discharging the mixture from the flow path without substantial additional release of vapors from the concentrated liquid hydrocarbon material and without a substantial change in pressure, and permitting the released vapors rapidly to separate and become isolated from the concentrated liquid hydrocarbon material, the concentrated liquid hydrocarbon material in-cluding said at least one hydrocarbon fraction and the released vapors including a second hydrocarbon fraction.

2. A process according to claim 1, wherein steam is continuously introduced into the flow path to strip a third hydrocarbon fraction from the liquid hydrocarbon material.

3. A process according to claim 1, wherein the released vapors are separated and isolated from the concentrated liquid hydrocarbon material at a pressure below atmospheric pressure.

4. A process according to claim 3, wherein the liquid hydrocarbon material and the mixture are passed through the portion of the flow path at a pressure below atmospheric pressure.

5. A process according to claim 1, wherein the liquid hydrocarbon material is heated before being introduced into the flow path.

6. A process according to claim 1, wherein the released vapors are permitted rapidly to separate and become isolated from the concentrated liquid hydrocarbon material by moving upwardly relative to the concentrated liquid hydrocarbon material and wherein the upwardly moving vapors are spiralled outwardly relative to the axis of upward movement, thereby to separate, centrifugally, liquid entrained in the vapors.

7. A process according to claim 1, wherein at least part of the concentrated liquid hydrocarbon material is con-tinuously introduced into a second flow path of which a portion in cross-section transverse to the flow of the concentrated liquid hydrocarbon material therethrough is elongated in one direction and relatively narrow in a generally perpendicular direction, the process steps of claim 1 being repeated to produce additional released vapors and a more concentrated liquid hydrocarbon material, the more concentrated liquid hydrocarbon material including a third hydrocarbon fraction.

8. A process according to claim 1, wherein at least part of the released vapors are condensed and introduced into a second flow path of which a portion in cross-section transverse to the flow of the condensed vapors therethrough is elongated in one direction and relatively narrow in a generally perpendicular direction, the process steps of claim 1 being repeated to produce re-released vapors and concentrated condensed vapors, the concentrated condensed vapors including a third hydrocarbon fraction.

9. A process according to claim 1, wherein the liquid hydrocarbon material includes liquid hydrocarbons and water mixed therewith as an emulsion, the water being volatilized in the flow path to form a part of the released vapors.

10. A process according to claim 1, wherein the liquid hydrocarbon material includes liquid hydrocarbons, water mixed therewith as an emulsion, and insoluble solids, the water being volatilized in the flow path to form a part of the released vapors and the insoluble solids being included in the con-centrated liquid hydrocarbon material.

11. A continuous process for spearating a liquid hydrocarbon material into two distinct fractions of high definition, which comprises continuously introducing the liquid hydrocarbon material into a flow path of which a portion in cross-section transverse to the flow of the liquid hydrocarbon material therethrough is elongated in one direction and relatively narrow in a generally perpendicular direction; passing the liquid hydrocarbon material through the flow path while supplying heat at least along the portion of the flow path to cause the volatilization of the fraction having the lowest boiling point in the portion of the flow path; continuing to pass a mixture of concentrated liquid hydrocarbon material and vapors released therefrom through the portion of the flow path while continuing to supply heat thereto, thereby to effect a high rate of vapor release and impart a high velocity to the mixture as it passes through the portion of the flow path; discharging the mixture from the flow path, without substantial additional release of vapors from the concentrated liquid hydrocarbon material and without a substantial change in pressure, and permitting the released vapors rapidly to separate and become isolated from the concentrated liquid hydrocarbon material, the released vapors including one of said two distinct fractions and the concentrated liquid hydrocarbon material including the other of said two distinct fractions.

12. A process according to claim 11, wherein steam is continuously introduced into the flow path to strip the fraction having the lowest boiling point from the liquid hydrocarbon material.

13. A process according to claim 11, wherein the released vapors are separated and isolated from the concentrated liquid hydrocarbon material at a pressure below atmospheric pressure.

14. A process according to claim 13, wherein the liquid hydrocarbon material and the mixture are passed through the portion of the flow path at a pressure below atmospheric pressure.

15. A process according to claim 11, wherein the liquid hydrocarbon material is heated before being introduced into the flow path.

16. A process according to claim 11, wherein the released vapors are permitted rapidly to separate and become isolated from the concentrated liquid hydrocarbon material by moving upwardly relative to the concentrated liquid hydrocarbon material and wherein the upwardly moving vapors are spiralled outwardly relative to the axis of upward movement, thereby to separate, centrifugally, liquid entrained in the vapors.

17. A continuous process for separating a re-constituted crude oil, formed by combining two distinct petroleum fractions, into said two distinct fractions, which comprises continuously introducing the reconstituted crude oil into a flow path of which a portion in cross-section transverse to the flow of the reconstituted crude oil therethrough is elongated in one direction and relatively narrow in a generally perpendicular direction; passing the reconstituted crude oil through the flow path while suppling heat at least along the portion of the flow path to cause the volatilization of the fraction having the lowest boiling point in the portion of the flow path; continuing to pass a mixture of concentrated re-constituted crude oil and vapors released therefrom through the portion of the flow path while continuing to supply heat thereto, thereby to effect a high rate of vapor release and impart a high velocity to the mixture as it passes through the portion of the flow path; discharging the mixture from the flow path without substantial additional release of vapors from the concentrated reconstituted crude oil and without substantial change in pressure, and permitting the released vapors rapidly to separate and become isolated from the concentrated recon-stituted crude oil, the released vapors including one of said two distinct fractions and the concentrated reconstituted crude oil including the other of said two distinct fractions.

18. A process according to claim 17, wherein steam is continuously introduced into the flow path to strip the fraction having the lowest boiling point from the reconstituted crude oil.

19. A process according to claim 17, wherein the released vapors are separated and isolated from the concentrated reconstituted crude oil at a pressure below atmospheric pressure.

20. A process according to claim 19, wherein the reconstituted crude oil and the mixture are passed through the portion of the flow path at a pressure below atmospheric pressure.

21. A process according to claim 17, wherein the reconstituted crude oil is heated before being introduced into the flow path.

22. A process according to claim 17, wherein the released vapors are permitted rapidly to separate and become isolated from the concentrated reconstituted crude oil by moving upwardly relative to the concentrated reconstituted crude oil and wherein the upwardly moving vapors are spiralled outwardly relative to the axis of upward movement, thereby to separate, centrifugally, liquid entrained in the vapors.