US 3173859 A
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Description (OCR text may contain errors)
March 16, 1965 J. M. CHAMBERS cRANKcAsE onJ REFINING 2 Sheets-Sheet l Filed Aug. 24, 1961 Ns H w hbug ATTORNEYS March 16, 1965 J. M. CHAMBERS 3,173,859
CRANKCASE on. REFINING Filed Aug. 24, 1961 2 Sheets-Sheet 2 1 f f 1 4 1 M4 1 LU g1 l, 5 S m JU JL u I w q l Q m nl l LL n 0 y' i L i Q/ XQ *Q Sz d 3 *I l INVENTOR. JOHN M. CHAMBERS ATTO RNEYS United States Patent O 3,173,859 CRANKCASE OIL RElilNlNG .lohn M. Chambers, Westfield, NJ., assigner of fifty-five percent to Berks Associates, lne., Pottstown, Pa., a corporation of Pennsylvania Filed Aug. 24, 196i, Ser. No. inol' lt) Claims. (l. 26S-ld) This invention relates to the purification and refining of oils, and more particularly, to the removal of solid and liquid impurities from used crankcase oils, and to the separation of the purified oils into desired fractions.
Used crankcase oils obtained from either gasoline or diesel internal combustion engines contain a variety of impurities in the form of solid and liquid materials. The solid impurities may consist of carbon, dirt, and other foreign solids, and the liquid impurities generdly include water, gasoline, and light ends, as Well as acids and other undesirable Water-soluble components, such as water-soluble organic oils and phenolios.
Processes are known whereby used crankcase oils are purified and rened to recover usable grades of lubricating oils. The commercial processes involve rather complicated separation techniques, and cumbersome clay and acid treatments of the oil fractions obtained. Although these processes have enjoyed a limited success in the reclaiming of usable oils, they possess many disadvantages. One serious disadvantage arises out of the fact that the conventional reclamation procedures entail removal of smelly and deleterious residues which may not be safely discharged into streams and rivers without creating serious pollution problems.
The process of this invention makes possible the recovery from used crankcase oils or sharp cuts, and in a commercially economic manner, of lubricating oils having a suitable viscosity index and good color and odor characteristics, ranging in viscosity from about, for example, S.A.E. l to above SAE. 50, by distillation and fractionation, without utilization, necessarily, of acid and clay materials treatment to obtain good color and odor characteristics of the iinal product, and, at the same time, to accomplish this without cracking or degrading any lubricant component Within the used crankcase oil feedstock. In addition, this invention provides or the removal of both the water content and undesirable water-soluble components, such as water-soluble volatile organic oils and phenolics, from the used crankcase oils, so that Water obtained from the treated crankcase oil will be essentially free of such components and, after a minimum of further treatment, may be discharged directly into streams and rivers Without creating pollution problems. This aspect of the invention permits reclamation of used crankcase oils near large urban areas close to the source of such feedstock materials.
It is an object of this invention to enable used crankcase oils to be purified and refined by a distillation-fractionation treatment process for the reclamation of used crankcase oils, without coking of the solids content of the oils undergoing treatment, through the provision of a new and improved purification process by close fractionation, enabling the production of a variety of sharp lubricating oil cuts for use directly or for blending to make up commercial motor oil grades.
It is another object of this invention to purify and refine used crankcase oils to obtain sharp cuts of lubricating oils having good color and odor stability, and which are free of sulfur compounds and would be ideal charge stock for hydrogenation and further viscosity index improvement.
3,173,859 Patented Mar. l5, i965 "ice it is a further object of this invention to treat used crankcase engine oil from gasoline engines to obtain a lubricating oil having Sil-4() S.A.E. viscosity, and a viscosity index of and to reclaim diesel crankcase oils to produce lubricating oils of about 50 S.A.E., and a relativelyy low viscosity index of about 70.
It is still another object of this invention to provide for the reclamation of used crankcase oils by a distillation-fractionation treatment process in which the used crankcase oil feedstock is heated without vaporization to prevent coking during the said heating, and, at the saine time, to utilize the water content of the feedstock as a carrying medium during lthe vaporization of the heavy lubricating oil fractions during the distillationfractionation process.
It is a still further object of this invention to recover, as a high-boiling viscous bottoms product of the distillation-fractionation procedures, a high-boiling tarry material having a minimum of usable lubricating oil components which is free of clay, sludge and acidic materials and which, by blending with a portion of the lube oil forecut, will yield an oil composition comparable to Bunker C fuel oils which may be burned in the heating units utilized in carrying out the process of this invention.
It is still another object of this invention to provide for the reclamation of used crankcase oils utilizing novel separation techniques to obtain sharp cuts of lubricating oils having good color and odor stability without further treatment, but which may, if so desired, be further enhanced with a minimum use of acid and clay processing treatments.
Further objects and advantages will readily appear to those skilled in the art from the following description of the invention taken in connection with the accompanying drawings in which:
FIGURE 1 is a schematic flow sheet illustrating the process of this invention and typical apparatus usable therewith; and
FIGURE 2 is a semi-diagrammatic side elevational view, partly in section, illustrating the general arrangement of a three stage condenser utilized in the process of this invention.
In its broadest aspects, the process of this invention provides for the treatment of a feedstock comprised of used crankcase oils from gasoline internal combustion engines and diesel engines, or mixtures thereof, by subjecting the feedstock to a first fractionation under conditions which W'dl preclude any coking of the solids content of the feedstock or cracking or degrading of 1ubricating components of the feedstock, treating the overhead products produced thereby to remove undesirable water-soluble components from a water-containing `fraction, and subjecting the bottoms product toa second fractionation to obtain sharp cuts of lubricating oils and a usable bottoms product.
Referring to the drawing in general, it will bey observed that the process .utilizes equipment of the type normally found in petroleum fractionation and separation installations. This equipmentincludes heaters, fractionati-ng towers, condensers, separators, and strippers. In addition, suitable pumping, valving, and piping facilities are provided. Appropriate instrumentation may be easily incorporated within the system, as desired, to regulate various phases of the process, and to record the operation of each unit.
Heaters H-l and H-2 are conventional heating apparatus. Each of these heaters may be provided with a burner (not shown) supplied with fuel oil through lines 31 and 32, respectively, and may also be provided with suitable thermostatic controls'to regulate the amount of fuel oil throughput for controlling the heat output of each heater. Heater H1 is also provided with heating coils, 33, through which the used crankcase feedstock may ilow and be heated by the burners in a manner well known. Heater H-Z is provided with a similar heating coil, 34, for the purpose of supplying heat to the liquid materials passed through it.
Heater H-3 is a steam generator for converting high pressure-steam, as from an external source, to low pressure, superheated steam. In the embodiment disclosed, heater H-S is adapted to conveniently supply the steam requirements for all units of the system. High pressure steam from an external source may be introduced into the heater through line 4t) and is passed through a reducing valve 41 to effect a reduction of the steam pressure, for example, from 100 p.s.i.g. to about 25 p.s.i.g. The lowv pressure steam then enters heater H-3 and flows through parallel paths42, 43 and is heated therein to increase the temperature of the steam. Suitable outlets 44 and 45 lare provided in heater H-3 for. taking off the process steamV and directing it to appropriate units. It is contemplated in the embodiment disclosed that the low pressure steam produced will leave heater H-3 through lines 44 and 45 at a pressure of about 15 p.s.i.g. and a temperature of about 700 F.
Units A-l and A -2 are fractionation towers. Referring to fractionator A-1 which is sometimes hereinafter termed the heads column, it has been found in one embodiment of this invention that 14 trays designated, respectively, by the numerals in parentheses, are suitable for lthe reclamation of used crankcase oils. These trays are, for the most part, conventional bubble trays, designated 47. However, at least one tray, located in the vicinity of the feedstock entry port, is not a bubble tray. Thus, it is contemplated, that one of these trays, 48, be a total draw-off tray, and the other, 49, be a combined bubble tray and trap-oil tray. Draw-olf tray 48 is provided with a vapor chimney t), and a trap-olf tray 49 is provided with Aa downpipe 51. In the preferred embodiment, it has been found that the used crankcase oil feedstock may be introduced between the fifth and sixth trays, that is, between the total draw-off tray 48, and the trap-off tray, 49. Line 53 provides for flow of liquid from the trap-olli' tray 49 around 'the total draw-olf tray 48 to the lower section of the tower. Suitable valves and meters may be incorporated in line 53 to control the amount of liquid taken off the trap-olf tray.
Fractionator A-2 which is sometimes hereinafter referred to as the lube oil column, includes a plurality of conventional bubble trays 106, as well as a plurality of corrugated bubble trays. Preferably, at least three 'corrugated bubble trays, designated A, B, and C, may be 'utilizedwi th these trays comprising the lowermost trays fY fthe fractionating tower or column. Each of the corrugated trays is provided with a downpipe 90 to permit downward ow of liquid to the subjacent tray. The vapors formed in the tower flow upwardly through slots formed in the corrugated bubble trays. Between the uppermost corrugated tray and the first conventional bubble tray, a demister pad 93 may be utilized to knockback liquid particles entrained in the rising vapors, in the usual manner.
For the purposes of this disclosure, the respective bubble trays of towers A-1 and A-Z will be hereinafter referred to by the number found in parentheses above each tray, as illustrated in the drawing. The corrugated bubble trays of tower A-Z will be referred to by letters A, B, and C.
Tower A-3 is a water stripper of the usual form and is provided with conventional'bubble trays, indicated at 105. Provision is made for the introduction and removal of various iluid streams from the water stripper in a manner to be more fully disclosed hereinafter.
Condensers T-1 and 'I`-2 are associated with towers A-l and A-Z, respectively. Condenser T l is a stage condenser provided with three zones or compartments 56, 5'7 and 58, as generally indicated in FIGURE 1. Condensers T-1 and T-2 are structurally the same, and are shown in greater schematic detail in FIGURE 2. Although the description of the condenser of FIGURE 2 will, for the most part', be confined to condenser T-l, it should be understood that the description is also appropriate to condenser T-2. Condensers T-1 and 'I`-2 are each designed 'to operate under a vacuum of about 100 mm. Hg, and serve to reduce the load on the settling vessels or decanters VD-l and D-2, to be described in detail hereinafter.
Referring to FIGURE 2, it will be seen that condenser T-1 is, basically, a shell-and-tube type of condenser which is suitably baffled to separate the liquid products produced during 'the various stages of condensation. The condenser is provided with a shell 11) enclosing a tube bundle comprised of tube sheets 112 and associated condenser tubes 114, only some of which are shown in this figure. Extending radially outwardly from and substantially above the central longitudinal axis of the tube bundle to the inner surface of the shell is a vapor-directing baille 116 carried by 'the tube bundle and disposed near the vapor inlet end of the shell; a similar baille 124 being located near the exit end. An intermediate vapor directing baille 1211, also carried by the tube bundle is located substantially midway between the bailles 116 and 124 and extends radially outwardly from and below the central longitudinal axis of the tube bundle to just beyond the outermost circular row of tubes of the bundle so as to be spaced circumferentially from the inner surface of the bottom of the shell.
Extending downwardly from the outermost circular row of tubes of the bundle, and spaced therefrom, and in contact with the inner surface of the bottom of the tube shell, is baille 118. Batlle 118 is located between battles 116 and 124, but is nearer baille 116 than baille 124. Batlle 11S, in addition to any vapor directing functions it may perform, serves to prevent the flow of condensed liquids from zone 56 to subsequent zones, 57 and 58.
Batlle 122 is located between baffles 12@ and 124, but isnearer to baille 120. Batlle 12,2 extends radially outward from the outermost circular row of tubes in the bundle, but is spaced from the inner surface of the bottom of the shell, and may also be slightly spaced from the outermost circular row of tubes, as shown in FIG. 2. Batlle 122, being spaced from the lower inner surface of the tube shell, permits communication between zone 57 and zone 5S. Batlles 116, 120 and 124 provide a tortuous path for the overhead vapors, from tower A-l, entering the condenser through line 52.
Cooling water is admitted into tubes 114 through line 63 and leaves the condenser by line 64.
The overhead products from tower A-l are fed via line 52 into condenser T-1 and first pass downwardly into zone 56. The temperature relationship between the cooling water introduced through line 63 and the overhead pnoducts from tower A-l is such that the water fraction in the overhead products does not condense during the passage of said overhead products through the first and second stages of the three stage condenser, but condense substantially only in the third stage. To achieve this result, the temperature in the first and second Zones is maintained above the dew point of water at the operating pressure of the condenser. Under these conditions of operation, a substantially dry lube oil forecut will condense in zone 56 which may be taken on" through line 55 and returned to tower A-l as recycle. A substantially dry gasoline fraction will condense in zone 57 which may, if desired, be taken off through -line 6d. A water fraction containing the smelly heads product will condense in zone 5S and may be removed through line 65. Line S9 provided at the exit end of condenser T-l permits ready removal of the non-condensibles.
Condenser T-Z is also a stage condenser structurally similar to T-l, as noted above, and is also adapted to operate at a vacuum of about lGO rnm. Hg. Cooling water is admitted into condenser 'i12 through line 35 and is removed through line de. The temperature relationship between the cooling water passing through condenser T-Z is the same as that described for the cooling water passing through condenser T-. Suitable con* nections are provided for communicating with jet pumps 79o and '7Gb which supply the desired vacuum for condensers T-l and T-Z. Suitable air bleed lines, '79, are also provided for each of the condensers.
Associated with condenser T-l is a decanter or separator D-. A similar separator D-2 is associated with total condenser T-2. According to a preferred embodiment, the stream entering separator D-l will, generally, contain oil and water fractions which may be separated by a settling technique. In this way, an oil layer may be removed through line 53, and a water layer through line 77.
Separator DJ performs a similar function in separating the oil and water components obtained from condenser T-Z with the feed streams to the separator D-Z entering via line dil. The oil layer is decanted from D-Z?, by means of line 3l, and the water layer removed through line 78. The Water fraction, including soluble components dissolved tiereiu obtained from separators D-l and D-Z is taken by lines 77 and 78, respectively, to water stripper column A-3. Condensers T-l. and T-f?. serve to reduce the load on decantcrs D1 and D-Z, bccause the condensers effectively remove most of the oil before the water stream enters the respective decanters.
Unit T-S is a total condenser for condensing the overhead vapor taken olf through line 73 from water stripper A-S. Unit T-3 may be a conventional tube and shell condenser in which cooling water may enter through line 67 and leave through line ed, and which is pro vided with a vent 6?. The overhead products stream from stripper A-3 will consist, generally, of volatile organic oils, phenolic compounds and water vapor, which upon condensation, may -be taken through line 66 for treatment in separator D-l.
Suitable pumps P-l-P-9 are provided for circulating the various streams from unit to unit to maintain steady and continuous operation of the system. Obviously, more or less pumps may be used, or they may be arranged in a manner other than as shown without departing from the spirit of this invention. instrumentation including flow meters, flow and temperature recorders, valve controllers, pressure controllers, and Iother type-s of control apparatus may be utilized as desired. For the most part, the detailed instrumentation has not been shown as it forms no part of this invention.
The process of this invention will now be described .in detail on the basis of a continuous operation. Obviously, the invention may be practised batchwise, if desired, by providing the necessary controls for such an operation. It should be understood that the specic operating conditions, as temperature and pressure, mentioned in the detailed description, are offered as exemplary only, and are not intended, nor should they be construed, as limiting the scope of the invention. Similarly, references to the number, or specific type, of trays are likewise only exemplary.
The fresh feedstock F, comprising used gasoline or diesel eranlzcase oils, or mixtures thereof, or other A etroleurn stocks contining lube oil fractions to be separated, which would tend to crack and coke and, by reason of previous treatment may have a solids content tending to promote coiiing, is fed through line 39.3 and pumped through line 37 into fractionator tower A-l by pump P-l. lt is contemplated that the feedstock will enter the tower between the fifth and sixth plates, that is, between draw-or'f plate d@ and trapotl plate 49, as illustrated in FIG. 1. The fresh feedstock enters the tower at ambient temperatures, between about 70 and l" F. ln the preferred operation of tower A-l, a liquid depth of about 3 ft. is maintained on Contact tray 4S, for the purpose of providing surge capacity to aid pump P Z pull off liquid to heater irl-l. Low pressure, superheated steam from heater ll-3 is introduced into the bottom of tower A-l through line d5, and controls the temperature of the liquid bottoms accumulating in the column base. The not liquid accumulating on tray ed is talen @if through line 39 and pumped Aby pump P2 through line 35 into heater H-l. The quantity of this liquid passed through heating coils 33 and back into tower Afl through line 36 in such that the oil need be heated only moderately before being fed to the column. This desired condition may be achieved by computing the heat requirements for the tower, and then controlling the throughput through the heater, such that the temperature rise for the oil passed through the heater may he small, for example, about 20-25 F. ln this way, colring of the feedstock in the heater coils may be effectively minimized, or completely eliminated, permitting long and continuous use of the heater without frequent stoppages for cleaning the heating coils.
The temperature of the hot liquid portion taken from tower A-l. and passed through heater H-ll is raised from about 650 F. to about 675 F. and is returned to the tower A-l at a point between the sixth tray, tray 49, and the seventh tray, both being conventional bubble trays. A portion of the hot feed entering the tower through line 3o is talren olf trap-oil tray 49 through line 3S and mixed with the fresh feedstock entering through line 37. In this way, a pre-heating of the fresh feedstock F entering through line 31B, and a vaporization of the water content and lower boiling components of the feedstock is effected by the hot oil supplied to the tower by the heater'. Because tray 49 does not have a downpipe, line 53 is provided to permit the net down-flowing liquids within the tower A-l to pass from the upper section of the tower (above tray f5.9) to the lower section onto a control bubble tray, the fourth tray, and thus by-pass collecting tray 8. rlhe flow of down-ilowing liquid may be controlled by a suitable valve level controller 53a inserted in line S3. Thus, vaporization of the water and the low boiling components of the feedstock is obtained in a zone of the tower As-ll, between the sixth and seventh trays, where depostion of solid materials suspended in the oil feedstock may talee place without .fouling of the bubble caps. The water content and low boilers vaporized at this point act as a medium for carrying upwardly in tower A-l, a portion of the lube oil fractions contained in the feed. rlhe vapor formed from the water content in the feed F serves to depress the effective total vapor pressure in the tower at points above tray 5, making possible a saving on the steam requirements which, ordinarily, would have had to be supplied to the bottom of the tower.
Tower A-l is preferably under a moderate vacuum of approximately mm. Hg or higher, such that the liquid bottoms, even though they are at a relatively high operating temperature, are still far below their boiling point, to permit vaporization of the lube oil fraction suticient to give redux in the amount required to eliect substantially complete separation of the lower boiling undesirable components. As noted above, at the operating temperatures and pressures, the water content of the fresh feedstock fed to tray o' is vaporized into steam, and this steam together with the high temperature stripping steam supplied to the bottom of the tower is employed in tower A-l, on and above tray d, as a carrying medium at and above this tray. Distillation in the presence of this steam permits the vaporization and distillation of the lube oil fraction at moderate vacuum and at temperatures suiiiciently low to prevent thermal decomposition of the oil fractions contained in the original feedstock.
' The overhead vapor removed through line 52 includes water, heads, gasoline, and lubeV oil forecut fractions. The overhead Vapor is taken to the Vacuum stage condenser T-l through line 52 where the lube oil forecut and gasoline fractions may be condensed under operating conditions of temperature and pressure above the dew point of water to produce a substantially dry product for use as reflux in the heads column A-ll, and to produce the heads product. The lube oil forecut reflux component will condense in zone 55 and may be taken olf through line 55 as illustrated in FIG. l. The gasoline fraction, if any, will desirably condense in zone '7, and may be taken olf through line 60. The gasoline `fraction may also be combined in line 53 for use as reflux along with the lube oil forecut from line 55, or it may be passed through line 62 to storage.
The water fraction will condense in zone 58, the third stage, and may be taken ott through line 65 connected to separator D-l. The structure of condenser T-l is such that a substantial part of the oil component in the overhead vapors will desirably condense in the rst zone 5d, and in this way, only small amounts of oil will be carried through with the water vapor to be condensed in zone 5S, thereby relieving the load from decanter D-l. If desired, the gasoline fraction condensed in zone 57 may be combined with the water fraction obtained in Zone 58, with the combined fractions being taken olf through line 65. This procedure may be followed, for example, when the gasoline fraction yield is negligible. These two fractions may be combined by closing the valves in lines 60 and 62, so that the outlet for zones 57 and 5S is through line 65.
Separator D- serves as a decanter for the separation of any oil components from the water fraction, because the oil components will lloat as a layer on the water fraction. These oil components comprise the smelly heads products, and may be drawn off the top of separator D-l and may be combined with the lube oil forecut and gasoline fractions leaving by virtue of lines 55 and 6i), with all three products combined in line 53, and sent into the tower A-l as reflux. The water fraction is removed from separator D-ll through line 77 and is taken to water stripper A-3.
The water fraction includes water and water-soluble impurities such as soluble organic oils and phenolic com- If desired, the valve in line 53 may be closed so that the heads product is taken off through the line 61 and passed to storage. This heads product contains sulfur and other smelly impurities removed from the crankcase oil feedstock. Other products from lower A-1 may be taken olf as liquid side streams near the top of the tower, as, for example, at the eleventh, twelfth and thirteenth bubble trays, 47, through line 54. These products will also consist of lube oil forecuts of various boiling ranges. These may be used for blending with the bottoms from the fractionator A-Z to make a burning oil .equivalent to Bunker C fuel.
The feed to the water stripper A-S comprises the water' fraction removed from separator D-1 through line '77, as Well as a similar water fraction obtained from separator D-Z through line 7S, as will be described in greater detail hereinafter. Low pressure steam is introduced to the lower end of water stripper column A-S through line 74, and is passed counter-currently to the water fraction fed at the top of the tower A-S through line '77 and 78. The bottoms product leaving unit A-3 through line 76 consists essentially of pure water and the overhead vapor taken olic through line 73 contains the volatile organic oils, sulfurs and phenolics generally found in used crankcase oils. The stream taken through line 73 is then passed to total condenser T-3 and `condensed by means of the cooling water entering and leaving the condenser through line 67 and 68, respectively. The condensate from unit T-3 is taken olf through line 66 and is combined withthe water fraction taken from zone 5S, the
third stage 'of condenser T-l.V The combined stream from lines 65 and 66 is fed to separator D-f, as shown, and is separated as described above. Total condenser T-S may be operated at atmospheric pressure.
The feedstock to fractionator A-Z comprises the liquid bottoms taken from fractionator A-i through line 91 by means of pump P-S. The bottoms liquid is caused to enter the tower just above the modified corrugated tray C. Low pressure superheated steam is supplied to the bottom of the column A-2 through line 44. A portion of the bottoms product in tower A-Z is removed from the tower A-Z, passed through pump P-3 and line 88 and through heating coils 34 of heater H-2. The temperature of this stream is about 650 F. as it leaves tower A-2, and is at about 675 F. after leaving heating coil 34. Again, the passage of this stream through heating coil 34 is such as to prevent coking. This feed Vstream is combined, through line 89, with the bottoms product taken from tower A1 through line 91. In this way, the bottoms product fed to tower A-Z is pre-heated in a manner similar to that for pre-heating the fresh feed to tower A-i. It should be noted that the heater H-Z serves to heat the bottoms product of tower Av2 to a temperature such that when the heated oil is mixed with bottoms product from tower A-l, the latent heat necessary for vaporization in tower A-Z will have been supplied as sensible heat to the bottoms prior to entry into tower A-Z. Also, the live steam supplied through line 44 to tower A-Z is used to control the effective boilinfr point of the feed in tower A-1. Thus, it may be seen that the live steam depresses the boiling point of the feed in tower A-2, and makes the use of a high vacuum unnecessary within the tower. Tower A-Z is also operated under a moderate vacuum of about 100 mm. Hg, with the vacuum applied through the jet pump 7tlb, as indicated.
The overhead vapors from tower A-Z are taken off through line S7 and consist essentially of water from the stripping steam, spindle oil and a fraction from cut No. 1 for reuxing. These overhead vapors are taken to stage condenser T-2, and are condensed by cooling water entering and leaving through lines SS and 86, respectively. Reflux for tower A-Z is ten off from condenser T-Z through lines 82 and S3. Water and residual oils are removed through line Sti and taken to separator D-Z which functions in the manner similar to separator D-l. The oil fraction removed from unit `D2 is taken through line Si, and may be combined, in part, with the reux components from lines 82 and S3 and fed as a redux component through line 84 to the top of tower A-Z. A portion of the three combined streams is also diverted by means of line 7S to tower A-i for use as reflux in that tower. The water fraction from D-Z is taken by line 78 to water stripper A-3, and treated in the same manner as the water layer from D-, as heretofore described.
The desired lubricating oil cuts reclaimed are removed as side streams from various plates of tower A-2. The first cut may be taken off through lines 97 and 98. A second cut may be taken off through lines 96 and 99,
,a third through lines 95 and 100, and a fourth through lines 94 and 101. As indicated in the drawings, suitable pumps P-S-lLS may be used in taking oif the desired cuts from the tower A-2.
The lower separating plates in tower A- are not conventional bubble trays but, preferably, comprise corrugated trays having slots formed therein, with suitable downpipes provided in each of these trays to permit contacting of the circulating oil stream with steam so as to minimize the possibility of plugging of these trays. These corrugated trays are designated A, B and C, and function in a manner well-known to those skilled in the art. Demister pad 93 is provided above tray C to prevent entrainment of color bodies in the vapor passing up the tower.
It should be noted that a portion of cut d is taken oil through line 192, circulated baci( to tower A-2 and caused to enter the tower between the iirst and second bubble plates. This stream through line 102 is wash material and advantageously may comprise about 20% of the total streams taken olf through lines 98-101. The wash stream acts in conjunction with the demister pad 93 to insure that the desired lubricating oil products taken oil as side streams possess good color properties, by preventing entrained color bodies from passing up through tray 2.
The lubricating oil cuts obtained from tower A-2 differ from each other in their respective viscosities and possess good color and odor characteristics. The cuts may be blended with each other to obtain lubricating oils having viscosities different from each of the individual cuts blended, as is well-known. If desired, the cuts may be further subjected to the conventional acid and clay treatments to enhance the color and odor characteristics, but such treatment will be minimal because of the eiiiciency of the purication process forming this invention.
The invention will be further demonstrated by reference to the following illustrative example.
A feedstock comprising a used crankcase oil containing about 6.5% by weight of water is fed into tower A-l through line 30. The temperature of the fresh feed is between 70-S00 F., and the rate of feed to the tower, for the purpose of this example, is 32 gpm. Low pressure, high temperature steam at about 700 F. is introduced into the bottom of the column through line 5 at a rate of 5001b./hr. The hot liquid passed through heater H-l and recycled to the tower through line 36 will enter the tower at a temperature of about 675 F. After steady conditions for a continuous operation have been reached, the temperature of the overhead vapors leaving tower A-l through line 52 will be at a temperature of about 200 F. when the column is operated at a vacuum of about 150 mm. Hg pressure. The overhead vapors will include water, heads, gasoline and lube oil forecut fractions, and comprise about 14% of the feed, determined on a dry basis of the feed. t is to be understood, however, that the temperature of the overhead vapors will vary with the vacuum applied to the tower A-l.
The lube oil forecut taken olif as a side stream from tower A-l through line S4 will constitute essentially a gas oil fraction having an ASTM 50% distillation boiling point of 530` F. This product will be taken off at a rate of about 1.8 gpm., and may, as noted above, be combined with the bottoms product from tower A-Z to produce a fuel equivalent to a Bunker C fuel. The overhead vapor, as indicated earlier, also contains a lube oil forecut, which is substantially completely condensed in zone 56 of stage condenser T-l.. Since this condensed fraction is returned to the column as reilux, a portion .of it is removed with the lube oil forecut removed through line 54, as is well understood by those skilled in the art. The gasoline fraction, which may be taken off through line 62, will be about 1.4 gpm. and has an ASTM 50% distillation boiling point of 260 F. The heads product taken from decanter D-l through line 6l will be about 1 gpm., and has an ASTM 50% distillation boiling point of 200 F. The water fraction leaving separator D-1 through line '77 will include water-soluble impurities such as soluble organic oils and phenolic compounds in a concentration of about 450 ppm. or about 0.25%. As will be evident, the overhead vapors from tower A-l include fractions spanning a considerable temperature range such as low-boiling water-soluble organic oils, lietones formed by a cracking of the oil feed, aldehydes, amyl alcohols, sulfur compounds, and a lube oil forecut. The overhead products, therefore, include components which have boiling points ranging from about 160 F. to about 450 F.
The bottoms product taken from tower A-l through line 91 and introduced as feed into fractionation tower A-f; will be at about 590 F. Low pressure steam at a rate of 6800 lbs/hr. at a temperature of about 700 F. is introduced into tower A-Z. through line a4. At steady state operation of tower A-Z, and with the pressure in the tower at about mm. Hg, the temperaure of the overhead products will be about 460 F. The spindle oil fraction taken from condenser T-Z through line will be about 0.9 gpm., and will have an ASTM 50% distillation boiling point of 660 P. The spindle oil stream will have a viscosity of 70 SUS at 100 F. Cut 1, taken off through line 90, will form at a rate of about 3.9 gpm., and will have an ASTM 50% distillation boiling point of 730 F. The viscosity of cut 1l Will be approximately SUS. at 100 F. Cut 2, taken from line 99, will form at a rate of about 7.8 gpm., and will have an ASTM 50% distillation boiling point of 810 F. The viscosity of cut 2 will be about 240 SUS. at 100 F. Cut 3, removed from line 100, will form at a rate of about 8.4 gpm., and will have an ASTM 50% distillation boiling point of 910 F. The viscosity of the lube oil of cut 3 will be about 400 SUS. at 100 F. Cut al, removed through line 9d, will form at a rate of about 3.0 gpm., at least 50% having a boiling point of l020 F. The viscosity of cut l will be about 115 SUS. at 210 F. About 20%, or 0.6 gpm. of the product from line 101 (out d) is taken oli` by line 102 and returned to tower A-I?. as Wash material. The bottoms product from tower A-Z will be removed at a rate of about 1.5 gpm. and will consist primarily of tarry materials leaving the tower at about 650 F.
The bottoms product from water stripper A-, taken olf through line 76, will have a phenolic content reduced from about 450 ppm. to about ppm., and will have substantially no oil or order-producing components. This water stream may in some cases be directly discharged into a river or stream, or it may be further treated with ozone, chlorine dioxide, or sulfuric acid and potassium chlorate to further reduce the organic material content of the water stream. If desired, the Ph of the treated water stream may be adjusted to comply with any disposal regulations.
lt may be seen, then, that the process of this invention provides for treating used cranlcase oils to obtain sharp cuts of lubricating oils of good color and odor characteristics, as Well as providing a water fraction that with a minimum of further treatment ma f be used as make-up water, or may be discharged into streams without danger of pollution. The undesirable components, such .as the smelly heads products, which include phenolic and watersoluble organic compounds removed from the water component of the used cranncase oil, may be conveniently disposed of in any concentrated form in any manner desired. The reclamation of used crankcase oil is thereby accomplished without the necessity of further treatment with either acids or clay.
Although the invention has been described with particular reference to specific embodiments, the same are not to be construed as in any way limiting the invention. Reference is, therefore, to be had solely to the appended claims for the purpose of determining the scope of the invention.
What is claimed is:
1. A process for the purication and reclamation of feedstocks comprising crankcase oils, petroleum lube oil stocks containing impurities, and the like, to obtain sharp cuts of lubricating oils substantially odor and color free, comprising: subjecting said feedstock to a first fractional distillation to obtain a lirst overhead product, a iirst bottoms product and a lube oil forecut as a side stream; condensing said iirst overhead product to obtain a iirst substantially dry redux stream and a first water fraction; maintaining the temperature of said first substantially dry reliux stream above the boiling point of Water at the pressure at which said first fractional distillation is conducted; subjecting said Vfirst Water fraction to gravity separation to obtain a heads product and a first substantially oil-free Water fraction having dissolved impurities therein; subjecting the first bottoms product to a second fractional distillation to obtain a second overhead product, a second bottoms product and a plurality of sharp cuts of lubricating oil as side streams; condensing said second overhead product to obtain an oil fraction and a second Water fraction; subjecting the said second Water fraction to gravity separation to remove oil components therefrom and obtain a substantially oil-free second Water `fraction having dissolved impurities therein; and subjecting the first and second substantially oil-free Water fractions to steam stripping to remove dissolved impurities therefrom.
2. A process of the character described in claim vl, in which said second overhead product from said second fractional distillation is condensed in stages to obtain a second substantially dry reflux stream, a Water fraction, and a spindle oil having a viscosity of about 7G SUS at 100 F., and said second substantially dry reflux stream is returned to said second fractional distillation Vat a temperature above the boiling point of Water at the pressure at which said second fractional distillation is conducted.
3. A process for the purification and reclamation of feedstocks comprising crankcase oils, petroleum lube oil stocks containinc impurities, and the like, to obtain sharp cuts of lubricating oils substantially odor and color free, comprising: subjecting said feedstock to a first fractional distillation to obtain a first overhead product and a first bottoms product; condensing said first overhead product to obtain a substantially dry reflux stream and a first Water fraction; maintaining the temperature of said rst substantially dry reflux stream above the boiling point of Water at the pressure at which said first fractional distillation is conducted; subjecting the said first Water fraction to gravity separation to obtain a heads product and a first substantially oil-free Water fraction having dissolved impurities therein; subjecting the first bottoms product to a second fractional distillation to obtain a second overhead product, a second bottoms product and a plurality of sharp cuts of lubricating oils as side streams; condensing said second overhead product to obtain an oil fraction and a ,second Water fraction; returning a portion of said oil fraction as reux to said second fractional distillation While maintaining said oil fraction returned as reflux at a temperature above the boiling point of Water at the pressure at which said second fractional distillation is conducted; and combining the rst and second Water fractions and subjecting .them to steam stripping to remove dissolved impurities therefrom.
4. A process for the purification and reclamation of feedstocks comprising liquid crankcase oils, liquid petroleum lube oil stocks containing impurities therein, and the like, to obtain sharp cuts of lubricating oils substantially odor and color free, comprising: feeding said liquid V'components remaining after substantial removal of the low boiling components from said first tray zone, increasing the temperature of said portion, and reintroducing said heated portion into said first fractional distillation zone at a point in said first fractionalV distillation Zone above said first tray zone; introducing high temperature steam I vinto the bottom of said first fractional distillation zone; vseparating in said first fractional distillation zone from -said feedstock an overhead product, a bottoms product and a. lube oil forecut as a side stream; condensing said product into a substantially dry reflux fraction, a gasoline fraction and a water-fraction; subjecting said Water fraction to gravity separation to obtain an oil fraction and a substantially oil-free Water fraction containing dissolved impurities therein; and subjecting said Water stream to steam stripping to remove substantially all of said impurities fromrsaid stream to obtain a Water stream having a substantially reduced quantity of dissolved impurities.
5. AY process for the purification and reclamation of feedstocks comprising crankcase oils, petroleum lube oil stocks containing impurities, and the like, to obtain sharp cuts of lubricating oils substantially odor and color free, comprising: feeding said feedstock at an ambient temperature on to a first tray -zone of a first fractional distillation zone; removing a portion of the liquid on said first tray zone from said first fractional distillation zone, increasing the temperature of said portion, and reintroducing said heated portion into said first fractional distillation zone at a point in said first fractional distillation zone above said first tray zone; introducing high temperature steam in to the bottom 0f said first fractional distillation Zone; obtaining a first overhead product and a yfirst bottoms product from said first fractional distillation zone; condensing said first overhead product to obtain a first substantially dry reflux stream for said first fractional distillation zone and a first Water fraction; maintaining the temperature of said rst substantially dry refiux stream above the boiling point of Water at the pressure in said first fractional distillation Zone; removing from the said first Water fraction oil components contained therein to obtain a substantially oil-free first Water fraction having dissolved impurities therein; feeding said first bottoms product onto a tray zone in a second fractional distillation zone; introducing high temperature steam into said second fractional distillation zone at a point at least one tray zone above the bottom of said second fractional distillation zone; removing hot liquid from said second fractional distillation zone at a point below said one tray zone above said bottom; further heating said hot liquid and combining said further heated hot liquid with said bottoms product feedstock fed to said second fractional distillation zone to effect preheating of said bottoms product feedstock; obtaining a second overhead product, a ysecond bottoms product and at least one sharp cut of a lubricating oil as a side stream from said second fractional distillation zone; condensing said second overhead product to obtain a second substantially dry reflux stream for said second fractional distillation zone and a second Water fraction; maintaining the temperature of said second substantially dry reflux stream above the boiling po'mt of Water at the pressure in said second fractional distillation zone; removing from the said second Water fraction oil components contained therein to obtain a substantially oil-free second Water fraction having dissolved impurities therein; subjecting said first and second substantially oilfree Water fractions to steam stripping to remove substantially all of said dissolved impurities therefrom to obtain Water having a substantially reduced quantity of dissolved impurities.
6. A. process of the character described in claim 5, in which, the oil components removed from said first Water fraction are a heads product, and the removal of the said oil components from each said first and second Water fractions is by gravity separation.
7. A process of the character described in` claim 5, in which, the portion of said heated portion reintroduced into ysaid first fractional distillation zone containing predomi- .nantly the higher boiling components of said feedstock is Withdrawn from said first fractional distillation zone at a point along said first fractional distillation zone between the point of reintroduction and said first tray zone on to which said feedstock at ambient temperature is fed, and, in which, said Withdrawn portion is combined with said feedstock to increase the temperature thereof to effect preheating and vaporization of Water and lower boiling comi3 l@ ponents of said feedstock at its introduction into the said References Cited in the le of this patent firSS fictional SOI ZOIltee. d ib d I l i 5 I UNITED STATES PATENTS process o e c arac r escr e 1n c am in which, at least one of the sharp cuts of lubricating oil Iahike Mir-2;' removed as a side stream from said second fractional 5 2009079 ewllr M13/2 1935 distillation zone is returned to said second fractional dis- Bur ar Ju y 3 2,038,314 Ragatz Apr. 21, 1930 tlllatmn zone as a wash stream. 2 123 821 Ymlker July 12 1938 9. A process of the character descrlbed in claim 5, 1n 1331070 Youker Oct* 11 1938 which, at least three sharp cuts of lubricating oils are removed as side streams from said second fractional dis- 10 Kmel Aug' 14 1945 tillation zone having viscosities between about 110 SUS McCOrqudale Aug' 19 19/ o o 2,995,500 Dilbert Aug. 8, 1901 at 110 F. and abOH 400 at 100 F. 3 026 254 I Iuo haar 20 1962 l0. A process of the character described in claim 5, in 3,075,133() Stone Febz 26 1963 which a portion of said oil components removed from said second Water fraction is recycled to said first fractional 15 FOREIGN PATENTS distillation zone. 255,428 Great Britain Feb. 17, 1947