US3039939A - Hydrocarbon eduction apparatus and process - Google Patents

Description

June 19, 1962 c. J. WELSH 3,039,939

HYDROCARBON EDUCTION APPARATUS AND PROCESS Filed April 14. 1958 2 Sheets-Sheet 1 flaw/w 4441151 (7/1 42 11 c. J. WELSH 3,039,939

HYDROCARBON EDUCTION APPARATUS AND PROCESS 2 Sheets-Sheet 2 June 19, 1962 Filed April 14. 1958 HHIII m n Ava 7a! ax/zzzaji/rzmg United States Patent 3,039,939 HYDROCARBON EDUCTION APPARATUS AND PROCESS Charles J. Welsh, Rifle, Colo., assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California Filed Apr. 14, 1958, Ser. No. 728,282 17 Claims. (Cl. 202-6) This invention relates to an improved apparatus for educting hydrocarbon values from hydrocarbonaceous solids such as oil shale, bituminous sands, and the like, and in particular concerns means for attaining a uniform distribution of particle sizes within a retort apparatus of the type hereinafter more fully described.

:In Berg Patent No. 2,640,019 there is described a process for the recovery of hydrocarbon values from oil shale and the like which involves countercurrently contacting the shale with a hot flue gas which servesto educt the hydrocarbons from the shale at an elevated temperature. The apparatus in which such process is effected takes the form of a vertical retort essentially comprising a solidsfeeding section, a solids-fluid disengaging section, and a kiln section. The oil shale is introduced from an inlet hopper into the solids feeding section at the bottom of the retort, and is passed upwardly in sequence through the disengaging and kiln sections. Simultaneously, air or other oxygen-containing gas is introduced into the top of the retort, and is drawn downwardly into the kiln section. Within the latter, the air is preheated and is then employed to burn carbonaceous residue from the shale, thereby forming the aforesaid hot flue gas. As said flue gas passes downwardly through the rising bed of shale it educts the hydrocarbon values therefrom. The mixture of hydrocarbons and flue gas then passes into the disengaging section where the hydrocarbons are condensed in contact with the shale and are separated therefrom as well as from the flue gas, and are passed to storage or further processing facilities.

In operating the Berg process on a commercial scale, it has been found that optimum results depend to a large extent upon maintaining more or less well defined boundaries between the various zones which exist within the kiln section of the apparatus, and also upon maintaining said zones substantially in horizontal planes. It has further been found that non-level and indefinite zone boundaries are caused by a non-uniform distribution of shale fines, i.e., shale particles of less than about 0.5 inch size, in the rising mass of shale within the retort. Such non-uniform distribution of fines occurs by reason of the fact that the retort itself is constructed symmetrically around a vertical axis, whereas the inlet hopper through which the raw shale is fed by gravity into the solids-feeding section is displaced away from said vertical axis. Accordingly, the classification of shale particles which occurs when the shale drops through the inlet hopper results in the smaller sized particles, i.e., the fines, being introduced into the retort closer to one side than the other so that in any horizontal plane passing through the mass of rising solids within the retort the shale fines are non-uniformly distributed around the vertical axis of the retort. As stated, such non-uniform distribution adversely affects the juxtaposition of the various zones the retort, and leads to various operational difliculties, including poor temperature control, low eduction rates, and poor quality products.

It is accordingly an object of the present invention to provide means whereby the zone boundaries within the described type of retort apparatus are maintained Welldefined and in substantially horizontal planes.

Another object is to provide means for attaining a uniform distribution of solids fines around the vertical axis of an apparatus ofthe type described.

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A further object is to provide an improved apparatus for educting hydrocarbons from hydrocarbonaceous solids such as oil shale.

Other and related objects will be apparent as the description of the invention proceeds.

We have now found that the foregoing objects and attendant advantages can be realized by providing, in an apparatus of the type described, solids inlet means adapted to effect a substantially um'form distribution of fines around the vertical axis of the rising mass of solids within the retort. More particularly, we have found that, in the process described above, an advantageous distribution of fines in the mass of solids undergoing processing can be substantially improved by providing an apparatus in which the solids are fed downwardly by force of gravity into a solids-feeder section through an inlet hopper having a distribution plate or baflle extending partially across its throat and upon which the solids impinge in passing to the feeder mechanism. The invention thus comprises a particular type of solids inlet means in combination with a retort apparatus of the type referred to above, all as hereinafter described and illustrated in the drawings.

In the drawings which form a part of this application, and in which like parts are designated by like numerals:

FIGURE 1 is an elevational view, partly in cut-away section, of a retort apparatus of the present type;

FIGURE 2 is an enlarged fragmentary plan view of the feed hopper to which the invention particularly relates;

FIGURE 3 is a fragmentary plan view of said feed hopper, taken along line 3-3 of FIGURE 2;

FIGURE 4 is a fragmentary end view of said feed hopper shown attached to retort apparatus.

Referring now to FIGURE 1, the retort unit there shown comprises a solids-feeder section 14 communicating with a superimposed conical solids-fluid disengaging section 12, which in turn communicates with a superimposed conical kiln section 10. Solids-feeder section 14 contains a solids-feeder piston 16 which is reciprocated vertically by hydraulic cylinder 22. Feeder piston 16 and its actuating cylinder 22 are disposed within cylinder 18 which is supported on trunnion 20. A second hydraulic cylinder 24 is connected to the top of cylinder 18, and serves to reciprocate cylinder 18 around trunnion 20 and between the central opening which communicates with disengaging section 12 and solids inlet 23 which communicates with solids feed hopper 36. A curved shoe 17 extends outwardly from cylinder 18 and serves to close 01f solids inlet opening 23 when the cylinder is in the position shown and also to close off the central opening to the retort when cylinder 18 is in register with inlet opening 23. Conveyor 34 supplies raw shale to feed hopper 36 from a direction parallel to that of the axis of trunnion 2i). Feeder piston 16 is shown disposed at its upper limit of travel, having just completed forcing a charge of shale upwardly into disengaging section 12 and thereby displacing the entire mass of shale within the retort upwardly and causing shale ash to overflow the upper rim of kiln section 10. With feeder piston 16 in this position, cylinder 24 is operated so as to draw cylinder 18- to the left and into communication with solids inlet 23. Cylinder 22 is then actuated to retract feeder piston 16 into its lowermost position, whereupon a charge of shale passes from hopper 36 through inlet 23 into the upper part of cylinder 18. Cylinder 24 is then actuated to place cylinder 18 into communication with disengaging section 12. Cylinder 22 is then actuated to force feeder piston 16 upwardly, thereby discharging the shale charge into disengaging section 12. This sequence of operations is repeated continuously, thereby efiiecting a semicontinuous flow of shale upwardly through the retort.

Simultaneous with the above-described operationof the the surrounding separator case 60.

shale feeding mechanism, blower 78 takes suction on the retort via line 76, thereby drawing air through opening 32 in hood 26 which surrounds the top of the retort. Hood 26 is provided with a sloping bottom 30 which catches the'shale ash 23 overflowing the top of the retort and delivers the ash to conveyor 33 which delivers it to disposal means, not shown. The air entering opening 32 passes upwardly through hood 26 in countercurrent contact with the hot shale ash, and is thereby partially preheated. The partially preheated air then enters the top of the retort and passes downwardly into kiln section ill. Reading from top to bottom, the latter comprises a preheating zone 11 wherein the air is further preheated by countercurrent contact with hot shale ash, a combustion zone'19 wherein the air burns the carbonaceous residue from the educted shale to form the flue gas which con stitutes the eduction fluid, eduction zone 21 wherein the eduction fluid educts hydrocarbons from the shale, and a cooling zone 40 wherein educted hydrocarbons are condensed and eduction fluid is cooled by 'countercurrent contact with incoming cool raw shale. The educted hydrocarbons and eduction fluid are then drawn down into disengaging section 12 where the hydrocarbons are further condensed on the incoming cool shale and flow through perforations 62 in the side of disengaging section 12 into Within the latter, the condensed liquid products collect and form liquid level 64, and are drawn olf via line 65 and pump 72'at a rate regulated by valve 68 which is controlled by liquid level controller 70. The liquid product is then passed via line 74 to storage facilities, not shown. The uncondensed hydrocarbons and eduction fluid which pass as a vapor from disengaging section 12 through openings 62 into separator case 60 collect above liquid level 64 and are drawn through line 76 by blower 78 and delivered to mist separator 89 at a rate regulated by valve 84 which is controlled'by flow controller 88. Within mist separator 80, the gaseous components of'the vapor are separated from entrained liquids, and are passed via line 82 to storage facilities, not shown. The liquids received in separator 80 are passed to liquid product line 74 via line The foregoing subject matter constitutes a general indication of the mannerin which the eduction process operates and the general design of the retort apparatus. Considering now the special construction of feed hopper 36, and with reference to FIGURES 24 of the drawing, feed hopper 36 partly takes the form of a hollow semicylinder constructed of sheet metal or the like, and mounted on the top of feeder section 14 in such manner that its semicylindrical aids corresponds substantially to that of cylinder 18 when the latter is reciprocated into register with solids inlet 23. A pair of substantially parallel hopper sides 125 extend to separator case 6% from said seniicylinder form. Sides 125 are there attached so that hopper 36 is supported by the curved wall 126 of separator case 60, and the upper opening of the hopper is positioned with respect to raw shale conveyor 34 so as to receive solids therefrom. Within hopper 36, an inclined distribution plate 123 extends downwardly at an angle of about 45 from the upper periphery 124 of the hopper. Lower edge 128 of plate 123 is in a location which is approximately half-way across the diameter of the hopper, and lateral edges 127 are curved to fit snugly against the curved walls of the hopper and separator case 60.

The provision of distribution plate 123 feed hopper 36 effects an advantageous distribution of fines within the retort by reason of the fact that the fines are thereby fed substantially symmetrically around the vertical axis of the feeder piston, and hence substantially symmetrically around the vertical axis of the bed of rising solids within the retort. As the solids are being conveyed to the retort via conveyor '34, a substantial amount of settling occurs, and the fines become concentrated immediately adjacent the conveyor belt. As a result the fines are discharged into the hopper at a point more or less immediately below the end of the conveyor belt. The larger solids particles, however, are thrown forward off the end of the conveyor belt. Accordingly, in a hopper which has not been provided with a distribution plate, the fines accumulate at a point more or less immediately below the discharge point of the conveyor belt, whereas the larger particles accumulate adjacent that wall of the hopper which lies beyond the end of the conveyor. This same non-uniform distribution of fines prevails on the face of the feeder piston and, eventually, in the rising bed of solids within the retort, with the ultimate result that the porosity of such bed is asymmetric with respect to the vertical axis thereof. As previously stated, such nonuniform distribution of fines causes the various zones within the niln section of the retort to tilt out of the horizontal, and in particular causes uneven temperature profiles around the periphery of the burning zone. In an oil shale retorting operation without distribution plate 123, in which the conveyor terminating at a hopper edge, as shown in PEG. 4, was aligned in an east-west direction and fed from the east to the west, and the feeder piston oscillated to a vertical position from north to south, it was found that the porosity of the bed within the retort was considerably higher in the northwest quadrant, and that the combustion zone was lower in the northwest quadrant than elsewhere. More importantly, it was found that the skin temperature of the retort was several hundred degrees higher in the northwest quadrant. The fact that these phenomena occurred in the northwest quadrant, rather than due west, is attributed to the fact that the oscillation of the feeder piston from north to south tends to cause the fines to be concentrated somewhat to the south, so that while they are initially concentrated on the east half of the piston, when the latter swings into its vertical charging position the fines from a previous stroke on north side of the retort fall back into the south side of the piston. Thus fines become concentrated in the southeast quadrant of the retort, however, the southerly portion of such southeast quadrant fines concentration can, of course, be compensated for in part by a second similar distribution plate 223, as shown in FIG. 1, at a different elevation than the first distribution plate. The second distribution plate is faced so as to direct fines to the north, that is, away from the retort wall within the feed hopper.

After the feed hopper had been modified with a single plate in accordance with the present invention, the hot spot in the northwest quadrant substantially disappeared, and the boundaries between the various zones became more clearly defined in horizontal planes. Said modification consisted in welding a distribution plate to the east side of the upper edge of the feed hopper in such manner that the plate extended down into the hopper at an angle from horizontal of about 45 (that is, greater than the angle of repose for fines solids), and terminated about half-way across the hopper with its lower edge running in a north-south direction. In short, such modification was substantially as illustrated in FIGS. 2-4. With such modification, the fines which dropped substantially vertically off the end of the conveyor belt were caught on the distribution plate and slid down and over the lower edge of the same to fall substantially vertically to the bottom of the hopper in the vicinity of its central axis. The coarse particles, on the other hand, were thrown forward off the conveyor belt and ricochetted off the opposite wall of the hopper to be distributed more or less uniformly on the bottom of the hopper. Consequently, when the accumulatiomof solids within the feed hopper was deposited on the feeder piston and forced upwardly into the retort proper, the fines were more or less symmetrically distributed around the vertical axis of the retort.

' The foregoing hopper distribution plate and method of operation may be further explained for clarity in the following manner. Temperature surveys indicate that the F i) burning zone is lower, for example, on the north side toward the feed hopper and on the west side, toward which the solids feed conveyor discharges. This is presumably caused by greater bed porosity, and thus channeling of on the north and west.

The greater porosity on the north is attributed to the fact that the feed piston may fill to only 80 to 85 percent of capacity. When oscillating from north hopper position to south vertical feed position material falls back onto the piston from the first approached north side of the retort 'bed. This movement results in a screening action on the north side of the retort, fines being sifted from the retort back onto the feed piston and transported therein to the south. The feed hopper which slants from north toward the retort tends to counteract concentration of fines to the south, but only partially. The second distribution plate of this invention also tends to counteract this concentration.

The greater porosity on the west is attributed to the fact that the feed hopper is fed from the east, and the discharge end of the conveyor is directly above the east edge of the hopper. It is believed that fines fall to the hopper more or less directly vertically from the conveyor, while larger pieces of solids are thrown out farther to the west.

It has been found that in spite of passage through sam-- pling tower equipment prior to depositing on the feed conveyor, the concentration of fines in the east persists in a feed hopper supplied with an east feeding conveyor. The installation of the distribution plate of this invention in the feed hopper directs fines from the east to the center of the feed hopper. The single sloped plate described in the foregoing paragraphs is installed below the discharge of the feed hopper conveyor just inside the feed hopper. The plate covers the east half of the feed hopper, slanting to the west, directing all solids to the west. Fines hitting the plate slide down it and drop into the center of the feed hopper. Other larger solids distribute around such fines.

The foregoing method of handling solids, in the example, reduces temperature peaking in the northwest retort quadrant and produces a more uniform east-west burning zone.

The foregoing description of the invention is merely illustrative, and various departures therefrom may be made within the scope of the invention. Thus, while the distribution plate has been described as being sloped downwardly within the feed hopper at an angle of about 45, it will be understood that other slopes may be employed depending upon the nature of the solids being treated, the location of the conveyor, and the nature of the feeding mechanism. Similarly, the distribution plate need not extend into the hopper from a direction exactly parallel to that of the feeder cylinder trunnion; it may be offset somewhat to compensate for the re-distribution of fines on the feeder piston caused by the latters reciprocation. Other modifications and embodiments within the the art, and the true scope of the invention is to be determined by the scope of the appended claims and their equivalents.

I claim:

1. In an apparatus for fluid-solids contacting comprising a contacting vessel opening downwardly into a solids feeder case disposed therebelow, a solids inlet hopper opening downwardly into the top of said feeder case, an oscillating vertically-acting piston solids feeder disposed within said feeder case, means for oscillating said solids feeder in a vertical plane between said vessel opening and said hopper opening, and means for reciprocating said piston so as to receive a charge of solids as a mass from said hopper and force said mass upwardly through said contacting vessel, the improvement which comprises in combination therewith a fines solids sloped distribution plate located in a flow stream of solids directed into said hopper, said sloped distribution plate having an upper edge substantially in peripheral alignment with respect to a side of said hopper, and said sloped distribution plate having a lower fines discharge edge centrally disposed across said hopper so as to direct fines substantially vertically along a line of fines discharge into said hopper below, said line of concentrated fines thereby being received into said oscillating vertically acting piston solids feeder from said hopper in such a manner that the central point :of said line of fines is centrally received thereby distributing fines in a controlled compensating manner in comparison to chance distribution by hopper concentration of fines prior to processing of solids in said contacting vessel.

2. Apparatus according to claim 1 in which said sloped distiibution plate is disposed at an angle from horizontal greater than the angle of repose of fines solids received thereon.

3. Apparatus according to claim 1 in which said sloped distribution plate is' sloped in a geographical direction which is substantially parallel to the geographical disposition of the axis of oscillation of said piston solids feeder.

4. Apparatus according to claim 1 in which said sloped distribution plate is contained within said hopper below the upper periphery thereof and in contact with said hopper in an internal hopper form fitting relation on plate edges with said discharge plate edge free and unattached.

5. Apparatus according to claim 1 in which solids are received into said hopper moving to some extent in the same geographical direction as the direction of slope of said sloped distribution plate.

6. Apparatus according to claim 1 in which there is provided a perforated fiuid disengaging vessel below said contacting vessel, a closed separator-settler vessel which surrounds said disengaging vessel, and means for removing at least one fluid stream from said separator-settler vessel.

7. Apparatus according to claim 1 in which there is provided a belt conveyor for directing a solids flow stream of various particle sizes into said hopper, said belt conveyor having a discharge end positioned adjacent said upper edge of said sloped distribution plate, said distribution plate being positioned to slant Within said hopper in a direction away from said belt conveyor.

8. In an apparatus for fluid-solids contacting comprise ing a contacting vessel opening downwardly into a solids feeder case disposed therebelow, a solids inlet hopper opening downwardly into the top of said feeder case, an

oscillating vertically acting piston solids feeder disposed within said feeder case, means for oscillating said solids feeder in a vertical plane between said vessel opening and said hopper opening, and means for reciprocating said piston so as to receive a charge of solids as a mass from said hopperand force said mass upwardly through said contacting vessels, the improvement which comprises in combination therewith a first fines solids sloped distribution plate located in a fiow stream of solids directed into said hopper, said plate having an upper edge substantially in peripheral alignment with respect to a side of said hopper, and said sloped distribution plate having a lower fines discharge edge centrally disposed so as to fines substantially vertically along a line of fines discharge into said hopper below, said line of concentrated fines thereby being received into said oscillating vertically acting piston solids feeder from said hopper in such a manner so the central point of said line of fines is centrally received therein, a second fines solids sloped distribution plate located at a different elevation than said first fines solids distribution plate, said second distribution plate having a lower fines discharge edge centrally disposed so as to direct fines substantially vertically along a line of fines discharge into said hopper below, which line of fines is centrally received therein meeting at a central position said line of fines discharged by said first distribution plate so as to distribute fines in a controlled compensating manner by multiple hopper concentration of fines prior to processing of solids in said contacting vessel.

9. Apparatus according to claim 8 in which there is provided a perforated fluid disengaging vessel below said contacting vessel, a closed separator-settler vessel which surrounds said disengaging vessel, and a means :for removing at least onefiuid stream from saidseparator-settler vessel. 7

10. Apparatus according to claim 8 in which there is provided a belt conveyor for directing a solid flow stream of various particle sizes into said hopper, said belt conveyor having a discharge end positioned adjacent said upper edge of said first sloped distribution plate, said first sloped distribution plate being positioned to siant within said hopper in a direction away from said belt conveyor.

11. Apparatus according to claim 8 in which said second plate is disposed slanted away from said disengaging and contacting vessels within said hopper.

l2. In a method for feeding solids of various sizes upwardly through treating zones which comprises receiving solids downwardly into an inlet zone, transferring said solids by an arcuate path in one geographical direction to a feeder zone and feeding solids vertically upwardly through said treating zones, the improvement in combinationtherewith which comprises separating said downwardly moving inlet solids of various sizes into two ranges of particle size groups in a friction zone of operation by contacting said solids against a 'iirictionally retarding structure in said friction zone, the smaller range of said solids particles being more frictionally retarded than the larger range of said solids particles in downward movement in said friction zone, thereby distributing said smaller range particle size solids group in substantially a straight line across said feeder zone geographically aligned with the geographical disposition of said arcuate path of solids transfer, and distributing said larger range particle size group within said feeder zone on each size of said linearly disposed smaller range particle solids thereby providing pro-treating separation of solids into two ranges of particle size groups which exist in substantially the same physical disposition with respect to one another within the upwardlymoving. solids of said treating zones.

13. A method according to claim 12 in which said solids comprise oil shale and said treating zones comprise from bottom to top a fluid disengaging zone, a solids preheating zone, a fluid eduction zone, a carbon burning zone, and an oxygen preaheating zone.

14. A method according to claim 13 in which said shale solids received downwardly into said inlet zone are received from a solids conveying supply zone with some degree of forward momentum which momentum acts in a geograpl'iical direction at' a right angle to said linear distribution of smaller range particle size group.

15. A method according to claim 13 in which there is provided a plurality of sub-zones of friction retarding of solids within said friction step of operation, said disposition of the smaller range of solids particles having a multipie linear disposition in which more than one of said linear dispositions meet at a central position within said feeder zone.

16. A method according to claim 15 in which there are provided two of said linear dispositions of smaller range of solids meeting in a right angle pattern at a central position within said feeder zone, thereby compensating for quadrant'ly disposed uneven conditions within said treating zones. 7

17. in a solids retorting process wherein solids are moved upwardly through a retorting zone, and are fed intermittently into said retorting zone by means of a subjacent piston-cylinder feeder which oscillatesbetween a substantially vertical retort feeding position and an inclined solids receiving position, and wherein the solids supplied to said feeder piston vary substantially in size, the improved method for obtaining a relatively uniform crosssectional size distribution of solids in said retorting zone which comprises: preferentially distributing the relatively small size-range particles of solids so as to coincide with a generally planar axis of said feeder cylinder while in the solids-receiving position; and preferentially distributing the relatively large size-range particles 'on each side of said planar axis, thereby minimizing the concentration of fines in peripheral zones of said feeder cylinder and resultant unevendistribution in said retorting zone.

References Cited in the file of this patent UNITED STATES PATENTS 853,420 'Rehman May 14, 1907 2,587,686 Berry Mar. 4, 1952 2,627,455 Berg Feb. 13, 1953 2,654,594 Somogyi Oct. 6, 1953 2,871,170 Bewley et a1 Jan. 27, 1959 2,912,127 Blixrud Nov. 10, 1959

Claims (1)

12. IN A METHOD FOR FEEDING SOLIDS OF VARIOUS SIZES UPWARDLY THROUGH TREATING ZONES WHICH COMPRISES RECEIVING SOLIDS DOWNWARDLY INTO AN INLET ZONE, TRANSFERRING SAID SOLIDS BY AN ARCUATE PATH IN ONE GEOGRAPHICAL DIRECTION TO A FEEDER ZONE AND FEEDING SOLIDS VERTICALLY UPWARDLY THROUGH SAID TREATING ZONES, THE IMPROVEMENT IN COMBINATION THEREWITH WHICH COMPRISES SEPARATING SAID DOWNWARDLY MOVING INLET SOLIDS OF VARIOUS SIZES INTO TWO RANGES OF PARTICLE SIZE GROUPS IN A FRICTION ZONE OF OPERATION BY CONTACTING SAID SOLIDS AGAINST A FRICTIONALLY RETARDING STRUCTURE IN SAID FRICTION ZONE, THE SMALLER RANGE OF SAID SOLIDS PARTICLES BEING MORE FRICTIONALLY RETARDED THAN THE LARGER RANGE OF SAID SOLIDS PARTICLES IN DOWNWARD MOVEMENT IN SAID FRICTION ZONE, THEREBY DISTRIBUTING SAID SMALLER RANGE PARTICLE SIZE SOLIDS GROUP IN SUBSTANTIALLY A STRAIGHT LINE ACROSS SAID FEEDER ZONE GEOGRAPHICALLY ALIGNED WITH THE GEOGRAPHICAL DISPOSITION OF SAID ARCUATE PATH OF SOLIDS TRANSFER, AND DISTRIBUTING SAID LARGER RANGER PARTICLE SIZE GROUP WITHIN SAID FEEDER ZONE ON EACH SIZE OF SAID LINEARLY DISPOSED SMALLER RANGE PARTICLE SOLIDS THEREBY PROVIDING PRE-TREATING SEPARATION OF SOLIDS INTO TWO RANGES OF PARTICLE SIZE GROUPS WHICH EXIST IN SUBSTANTIALLY THE SAME PHYSICAL DISPOSITION WITH RESPECT TO ONE ANOTHER WITHIN THE UPWARDLY MOVING SOLIDS OF SAID TREATING ZONES.

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