US 3093420 A
Description (OCR text may contain errors)
June 11, 19 3 H. D. LEVENE ET AL APPARATUS FOR FEEDING FINELY DIVIDED SOLIDS Filed Sept. 8, 1961 3 Sheets-Sheet l P0 WOEEED V 47 SOL/D5 HOPPEB RESERVOIR COMPRESSOR 50L/D5 FEEDER IN VEN TORS Hmeaw D. LEI/ENE 7/90/40: 6 STEPHENSON BY EZEQI/IEL M0/vrE5 HTTOEIVEYS June 11, 1963 H. D. LEVENE ET AL APPARATUS FOR FEEDI-NG FINELY DIVIDED soups and Sept. 8, 1961 247 GAS'SOL/DS T0 REACTOR llll ll i 1 Hli GAS //v 3 Sheets-Sheet 2 INVENTORS f/meow B LEVENE 72/001145 Q STEPHENSON EZEQl/IEL Mo/vrss J1me 1963 H. D. LEVENE ETAL 3,093,420
APPARATUS FOR FEEDING FINELY DIVIDED SOLIDS Filed Sept. 8, 1961 3 Sheets-Sheet :5
INVENTORS f/nk'ow D. laws/v5 fi/OMHS Q STEPHENSON EZEQU/EL Man/r55 United States Patent 3,093,420 APPARATUS FOR FEEDING FINELY DIVIDED SOLIDS Harold D. Levcne, Thomas G. Stephenson, and Ezequiel Montes, El Paso, Tex., assignors to Fossil Fuels, Inc,
a corporation of Delaware Filed Sept. 8, 1961, Ser. No. 136,955 14 Claims. (Cl. 302-53) This invention relates to the feeding of finely divided solids from a low pressure source to a high pressure zone. It is especially useful for the feeding of finely divided solids in a fluid stream to a high pressure reaction zone where the fluid is utilized along with the solids, for example, the feeding of pulverized coal with hydrogen to hydrogenation systems operating at pressures from 500 to 6,000 pounds per square inch, the feeding of catalysts with reactant gas, the feeding of pulverized fuels with primary air to high pressure combustion processes, etc.
Heretofore, various means have been utilized to feed finely divided solids to zones of high pressure. Hoppers pressurized to the same pressure as the system have been employed so that the flnely divided solids would feed by gravity to the system. It has also been proposed to employ a closed hopper in which the finely divided solids are fluidized by a gas at a higher pressure than the system. The hopper is discharged to the system by blowing the finely divided solids through a pipe located at the bottom of the hopper. Such apparatus possess several serious disadvantages. First, when the hopper is empty, the high pressure gas, which occupies the entire volume of the hopper, must be vented before the hopper again can be filled, thereby resulting in loss of energy and waste of gas. Secondly, the pressure differential between the hopper and the system often fluctuates so that regulation of the quantity of finely divided solids discharged to the system is very diflicult.
Recently, this problem was partially solved by use of a novel floatingspiston type feeder, disclosed in copending application Serial No. 769,380, now Patent No. 3,001,652. However, some inherent difficulties remained. For example, the available volume could not be completely utilized since introduction of gas at the bottom fluifed the solids and increased the volume of solids. For this reason, the vessel could be charged with only about /3 of its volume with pulverized solids. Also, there is a tendency toward abrasion diflioulties at the piston seal with the walls of the feed vessel.
An object of the present invention is to avoid the aforementioned difiiculties and provide a more readily controllable means for transporting finely divided solids with a gas from one zone to another.
Another object of the invention is to provide an apparatus for feeding flnely divided solids from :a low pressure reservoir to a high pressure zone in a continuous and uniform manner.
The invention will be further described by reference to the accompanying drawings, in which:
FIG. 1 is a schematic representation of a system employing the finely divided solids feeder of the invention, the feeder being shown in vertical section;
FIG. 2 is a horizontal cross-section on line 22 of FIG. "1, showing further details of the feeder piston;
FIG. 3 is a vertical sectional view of an alternate embodiment of the feeder of the invention;
FIG. 4 is a horizontal cross-section taken on line 4-4 of FIG. 3;
FIG. 5 is a horizontal cross-section of the feeder of FIG. 3, taken on line 5-5 of FIG. 3;
FIG. 6 is a fragmentary vertical sectional view showing a modified type of piston head which can be employed with a piston of the type shown in the feeder of FIG. 3;
3,093,420 Patented June 11, 1963 FIG. 7 is a horizontal sectional view taken on the line 77 of FIG. 6;
FIG. 8 is a top view of a conical baflle used with the piston head shown in FIG. 6, said baffle having been removed from the piston head for purposes of illustration;
FIG. 9 is a fragmentary sectional view showing a modi- :fication of the baflle illustrated in FIG. 6.
Referring now to the drawings in detail, in FIG. 1, the powdered solids (feeder generally designated as 1, comprises a steel cylinder 2 closed by a top 4, which is secured thereon by means of a plurality of bolts 6 through flanges 8 and 9. A suitable sealing means 10 is placed between the flanges 8 and 9 so as to form a high pressure seal when the bolts are tightly drawn. It is understood that for high pressure use, the walls of the cylinder 2 and cover 4 should be of substantial thickness. The cylinder 2 provides a powdered solids feed chamber 12 in which a hollow feed piston 14 is mounted. The feed piston 14 and feed chamber 1 2 are arranged for relative reciprocal movement, i.e., one of these members is arranged to remain stationary while the other member is movable. In the structure illustrated, the piston 14 is the stationary member while the feed chamber is designed for reciprocal movement. However, it will be apparent that the piston could be arranged to move in a static-nary feed chamber.
The sides of the piston 14 are provided with a plurality of sealing rings 17 and 18, which slidably engage the walls of the chamber 12 in the manner of automobile engine piston rings.
The lower portion of piston 14 is connected to a removable cylindrical piston head 20 by horizontally, radially extending bolts 24. The piston head 20 provides a gas distributing means and a collecting means for the powdered solids in chamber 12, as will hereinafter be de scribed. The piston head 20 is spaced from the walls of the cylinder 2 toprovide an annulus 22 to allow for passage of a high pressure gas completely around the periph cry of the piston head and adjacent the chamber walls. Passages 26 are radially spaced throughout the piston head 20 to evenly distribute the high pressure gas to the annulus 22. The relative locations of the internal passages 26 are shown in FIG. 2.
The lower portion of the piston head 20 is in the form of an inverted funnel, having walls 27. The angle of these walls determines the rate of acceleration of the exiting stream of gas and solids from the feed chamber 12.
A trisected conduit 28, as also shown in 'FIG. 2, extends through the centers of the piston 14 and the piston head 20 along the axis of cylinder 2 and passes through cover '4. The conduit 28 is welded or otherwise fixedly secured to piston 14 but has a sliding flt with the piston head 20 to permit this member to be removed by removal of bolts 24.
Within conduit 28, one of the passages 29 supplies powdered soldis from hopper 32 via conduit 33 and valve 34 to feed chamber 12 through the center of the piston head. A high pressure gas is conducted through another of the passages 30 and an opening 36 to a distributing chamber 38. This chamber is located between the piston 14 and the piston head 20. A plate 39 blocks off the center of the piston head so that all of the high pressure gas must enter chamber 38. Conduit 40 and valve 41 connect passage 30 to a gas compressor 42.
The third passage 31 of conduit 28 forms the outlet from piston head 20. Passage 31 is connected to high pressure reaction zone 45 by conduit 46 and the valve 47. A vent 50 communicates with the feed chamber 12 through valve 51 and passage 30 to permit the displacement of gas, if necessary during filling with the powdered solids from hopper 32.
The top of cylinder 2 is connected to a source of hydraulic fluid for raising the cylinder 2 with respect to the piston 14, the latter being held stationary by means of a collar 55 supported by beam 57. Suitable sealing means 57a are provided between the cover and conduit 28, the latter acting in much the same manner as a shaft in a hydraulic jack.
The hydraulic system comprises a conduit 52 coupled to cover 4, a pump 54, and a hydraulic fluid reservoir 56. A branch line 58 is provided to enable hydraulic fluid to drain back into the reservoir when the cylinder 2 is to be lowered. Valves 60 and 62 control the volume and direction of fiow of said hydraulic fluid.
In operation, valves 41 and 47 are closed, isolating feeder 1 from the reactor 45 and the gas supply. Valve 60 is opened to allow hydraulic fluid to drain to the reservoir as cylinder 2 is lowered by gravity and the expansion of any high pressure gas remaining in the feed chamber from a previous operation after valve 41 is closed. Valve 51 is then opened so that chamber 12 is open to atmospheric pressure. However, due to the very small amount of resilient high pressure gas remaining in chamber 12 after the piston has displaced the solids, there is very little loss of compressional energy or gas. Valve 34, which regulates the supply of powdered solids from hopper 32 is now opened and the powdered solids flow by gravity into chamber 12 to substantially fill it and form a stationary bed of solids in the chamber. Valves 34 and 51 are then closed and valve 41 to the compressor 42 is opened to permit high pressure gas to enter chamber 12 via conduit 40, passage 30, opening 36, distributing chamber 38, internal passages 26 and annulus 22. The entering gas aerates a narrow upper layer of the powdered solids and entrains these solids, carrying them up into the conical space defined by walls 27. Then valve 47 is opened and the gas and solids exit through passage 31 to the reaction zone 45. As the upper portion of the stationary bed is conveyed to the reaction zone 45, hydraulic fluid is pumped into the upper portion of chamber 12 to raise the cylinder 2 so that the piston head remains immediately over the aerated solids and controls the rate of solids supplied to the reaction zone. This control is efiected since the proximity of piston head 20 to the bed and the angle of the walls 27 regulate the volume of said chamber and consequently the amount of solids entrained by the constant high pressure gas. A gassolids mixture is continuously forced from the feed chamber until the piston head reaches its lower limit of travel, -i.e., the bottom of the feeder 1. The gas entering the feeder from the annular space 22 keeps the walls free of solids at the piston seals and eliminates abrasion difiiculties. When the piston has reached the bottom of its stroke, valves 41 and 47 are closed and valve 62, which regulates the flow of hydraulic fluid from the reservoir, is closed and valve 60 is opened to permit hydraulic fluid to drain back into the reservoir. The feed cylinder moves downwardly until its top 4 is adjacent the top of the piston 14. It will be apparent that the application of hydraulic fluid above the piston in this embodiment of the invention provides for pressure equalization across the piston, thereby relieving the pressure differential across the seals. The apparatus is then ready to repeat the aforementioned operation.
It is to be understood that a pair of feeding devices 1 may be connected to the same reactor for alternate use to provide a continuous supply of gas and solids to the reactor. Furthermore, the operation can be made entirely automatic by using valves and valve controls arranged to operate in response to a determination of the relative position of cylinder 2 with respect to the piston head.
In FIGS. 3 to 5, an alternate embodiment of the invention is shown. The powdered solids feeder 201 comprises a cylinder 202 fitted piston-like into a cylindrical tank 205. The sides of the cylinder 202 have seals 217 and 218, similar to seals 17 and 18 shown in FIG. 1. Tank 285 is connected by pipe 252 to a controlled source of hydraulic fluid having the same valve and pump arrangement illustrated in FIG. 1.
Disposed within cylinder 282 is a piston 214 which, together with the walls of said cylinder, defines a feed chamber 212. A removable piston head 220 is connected to the lower portion of piston 214. The piston 214, the piston head 220 and the cylinder 202 are structurally arranged in the same manner as piston 14, piston head 20 and cylinder 2, illustrated in FIG. 1.
As shown in FIGS. 3 and 5, a concentric pipe arrangement comprising an inner conduit 229 and an outer conduit 230 provides means for supporting the piston 214 and for loading and unloading the feed chamber 212. The outer conduit 230 extends from a gas distributing chamber 238 through piston 214 above the upper portion of cylinder 202. It is molded or otherwise fixedly secured to the piston 214. Pipe 240 and valve 241 connect the outer conduit 230 with a source of high pressure gas. Inner conduit 229 extends from the center of piston head 220, with which it makes a tight sliding connection, through the center of piston 214 and outer conduit 230. The upper end of conduit 229 is fitted to a bifurcated coupling 235. One branch of the coupling is connected to a powdered solids feed hopper by pipe 233 and valve 234. The other branch of the coupling 235 communicates with a reaction zone or other high pressure zone through pipe 246 and valve 247.
Inner conduit 229 is supported from an overhead beam 255 by a collar 257. A gas-tight connection, e.g., weld, secures the inner conduit 229 to the top 229a of the concentric outer conduit 230. Abutment of the top of conduit 230 against the beam 255 also helps support the piston assembly.
The operation of this embodiment is similar to the previously disclosed feeder. When cylinder 202 is at rest on the bottom of tank 205, the feed chamber 212 is loaded with a bed of powdered solids from the feed hopper through pipe 233, valve 234, and conduit 229. Valve 234 is then closed and valves 241 and 247 are opened. Hydnaulic fluid is permitted to enter tank 205. Piston 214, being rigidly secured to conduit 230, remains stationary and the cylinder 202 is raised to advance the bed of solids toward the piston head 220. High pressure gas, entering via pipe 240, valve 241, conduit 230 and chamber 238, discharges through said piston head into feed chamber 212 around the walls thereof to entrain the solids and conduct them into the center of piston head 220 in the manner of an inverted vortex. The gas-solids mixture exits through conduit 229 and pipe 246 to the reaction zone. The weight of the feed cylinder 202 causes it to return to the initial starting position once the solids have been exhausted and the hydraulic fluid has been allowed to drain back to its reservoir.
In FIG. 6 there is illustrated a modified type of piston head which may be interchanged with the piston head 220 of the feeder shown in FIG. 3. Piston head 70 comprises a hollow cylindrical housing 72 and a conical restrictor battle 74, which is positioned in spaced relationship within the inverted funnel-shaped lower portion of the housing. The piston head 70 is secured in piston 214 in the same manner as previously described. The bottom of inner conduit 229 abuts a shoulder 22912 formed in piston head 70 and a seal 2290 is provided in a groove 229d, also formed in the piston head. Disposed within said housing 72 are passages 76 extending from gas distribution chamber 238 at its upper end to recesses 78 located along the sides of said housing. Inclined passages 80 are drilled from these recesses inwardly to the hollow portion of said housing. Three tubular connectors 82, which support the baflle 74 within the housing 72 and conduct gas to the in terior of the baflie, are fitted in said inclined passages 80 to-threadably engage registering openings in the sides of said battle. The recesses 78 are sealed at the outer walls of housing 72 by threaded plugs 84.
The hollow portion of said housing comprises an upper circular section 86 which forms an extension of the passageway through conduit 229 and a lower section 88 in the form of an inverted funnel having walls 90. The outer configuration of bafile 74 is in the shape of a cone which is complementary to the hollow funnel section of said housing. The three connectors 82 permit proper adjustment of the bafile 74 with respect to the wall 90 of the housing. The baffle 74 is axially bored to provide a gas receiving chamber 92, which is in communication with passages 93 through tubular connectors 82.
A threaded gas directing insert 98 is positioned in the lower portion of the gas-receiving chamber 92 to accelerate and change the direction of the gas so that said gas will be tangentially distributed and pass along the lower surface 100 of the baffle. The threaded insert 98 comprises an upper tubular portion 102 and a lower solid portion 104, having a helical groove 106, a narrow neck section 108, and an enlarged cone-shaped head 110.
When the insert 98 is threaded into the gas-receiving chamber, the groove section forms a narrow, restricted gas passage and the neck section provides an annular chamber which discharges into a horizontally extending opening 112, defined by the lower face of said bafile and the base of said cone-shaped head.
The restrictor baffle 74 is so designed and positioned that an annular, tapered passage 114 is provided between said baffle and said housing. This passage must be sufiiciently wide to allow powdered solids to be loaded into the feed chamber from upper section 86 and yet narrow enough to insure a high gas velocity from the feed chamber durinrg discharge of the powdered solids.
In operation, the gas enters piston head 70 from a distributing chamber 238 via passages 76 and then passes through connectors 82 into gas-receiving chamber 92.
Once in the gas-receiving chamber, the several gas streams combine and flow into tubular section 102 and out through openings 103 into the groove section where the gas accelerates and obtains an angular velocity which allows the gas to discharge from the opening 112 so as to effectively displace solids in the feed chamber.
As the gas passes along the lower surface of the baffle, it entrains the powdered solids in the feed chamber and then together with said solids exits through annular passage 114 to the circular passage 86 and into a discharge conduit. This type of device is especially useful with solids which have a tendency to pack within the feed chamber.
FIG. 9 shows a modification of the insert to the restrictor baffle 74. The head 110' is pointed to dig into a mass of solids and is tapered to give a more divergent gas discharge at opening 112. A restricting plate 116 having a central orifice 118 is secured to the bottom of bafile 74 to control gas velocity. Thus, more gas will be directed into the bed of solids rather than along the lower surface of the baffle.
It will be understood that the foregoing description has been given by way of illustration and example and not by way of limitation, reference for the latter purpose being had to the appended claims.
1. Apparatus for feeding finely divided solids from a low pressure zone to a high pressure zone, comprising: a vertical cylindrical feed vessel having a feed chamber, a piston mounted in said chamber for relative movement substantially throughout the length thereof, means for effecting a controlled movement of said chamber with respect to said piston to effect said relative movement of the piston through the chamber, valved inlet means for introducing said solids below said piston from said low pressure zone to provide a bed of said solids in said feed chamber, outlet means in said piston for receiving said solids from said feed chamber upon relative movement of said piston and chamber to decrease the volume of said chamber, valved conduit means connecting said outlet means to said high pressure zone for transferring solids thereto, and means for introducing gas through said piston into said feed chamber to aerate the solids from the top of said bed and facilitate their entry into said outlet means, whereby said solids and gas may be continuously discharged to said high pressure zone until said bed of solids is exhausted.
2. The-apparatus of claim 1 in which the outlet means in the piston is provided with a downwardly directed surface in the form of an inverted funnel to cause the velocity of the aerated solids to increase sufficiently to cause said solids to become entrained in the gas flowing to the high pressure zone.
3. The apparatus of claim 2 wherein the periphery of said funnel-shaped surface is concentric with and adjacent to the cylindrical walls of the feed chamber and the means for introducing gas through said piston include means for introducing said gas between the periphery of said funnelshaped surface and said cylindrical walls to thereby free said walls of solids upon relative movement of said pis ton into the feed chamber.
4. The apparatus of claim 1 in which said inlet and outlet means include a vertically disposed conduit which supports said piston within said cylindrical vessel.
5. The apparatus of claim 1 in which said means for effecting a controlled movement of said chamber with respect to said piston include a pressure chamber between the top of said piston and the top of said vessel and means for introducing and withdrawing a pressure fiuid to and from said pressure chamber.
6. The apparatus of claim 1 in which said means for effecting a controlled movement of said chamber includes a pressure chamber positioned below said cylindrical vessel and formed by the bottom of the vessel and a cylindrical tank surrounding said vessel, and means for introducing and withdrawing a pressure fluid to and from said pressure chamber.
7. The apparatus of claim 1 in which the outlet means in the piston comprises a piston head having an axial opening communicating with the conduit means to the high pressure zone and gas distribution means whereby the entering gas is directed along the wall of said cylindrical vessel before contacting the bed of solids.
8. Apparatus for transporting finely divided solids from a reservoir at atmospheric pressure to a high pressure zone, comprising: a vertically disposed feed vessel having a feed chamber, a piston mounted in said chamber for relative movement throughout substantially the entire vertical length of said chamber, valved inlet means for introducing solids from said reservoir to said feed chamber below said piston to form a stationary bed of finely divided solids in said feed chamber, valved outlet means connecting said high pressure zone to said feed chamber, said inlet and outlet means extending axially through said piston and being secured thereto, collecting means secured to the lower portion of said piston and connected to said outlet means, means connected to said piston for introducing a high pressure gas into the feed chamber below said collecting means to aerate and entrain the solids at the top of said stationary bed, hydraulic means for moving said cylindrical vessel relative to said piston at a selected rate to maintain said collecting means immediately above the top of said stationary bed whereby the high pressure gas will entrain the solids from the top of said stationary bed into said collecting means and then to said high pressure zone.
9. The apparatus of claim 8 in which said piston is rigidly supported within a movable feed vessel by a vertically disposed conduit.
10. The apparatus of claim 9 in which said inlet and outlet means are at least partially provided by said vertically disposed conduit.
11. The apparatus of claim 8 in which the means for introducing a high pressure gas into said feed chamber includes an annular chamber cooperating with said col- 7 lecting means to distribute the gas uniformly into said feed chamber.
12. Apparatus for feeding finely divided solids from a low pressure Zone to a zone of higher pressure, comprising: a vertically disposed feed chamber and a piston mounted for movement downwardly within said feed chamber, means for introducing said finely divided solids from said low pressure zone into said feed chamber to form a bed of solids therein, said piston having a lower surface in the form of an inverted funnel terminating in an axial outlet for said finely divided solids, conduit means for connecting said axial outlet with said zone of higher pressure, and means for introducing a gas through said piston into said feed chamber to entrain solids from the top of the bed and carry them through said axial outlet.
13. The apparatus of claim 12 wherein said piston is References Cited in the file of this patent UNITED STATES PATENTS Cross Aug. 17, 1920 Goldie Nov. 15, 1960