CONTAINER, DEVICE AND METHOD FOR STORING OR PROCESSING PARTICULATE MATERIALS TO MINIMIZE OR ELIMINATE VIBRATIONS SUCH AS QUAKING OR SHAKING

Abstract

A container with lower vibrations, such as quaking and shaking as well as noise effects, known also as hooting, honking or howling, and an effective and cost-competitive method and device to decrease such phenomena during the discharge of granular material particles from silos, hoppers, bins, reactors and in general containers for storing or processing such granular material particles. The container includes at least one baffle that is attached to the container wall, in the lower portion or at the bottom of the tapered discharge part of said container, protruding towards the central axis of its tapered discharge part. The baffle forms a stagnant zone in the bed of the granular material particles in contact with the container wall whereby the particles in that zone flow under the friction against other particles instead of the friction between the particles and the wall.

Claims

1. A container for storing or processing granular material particles having lower vibrations, shaking, quaking and/or noise during discharge of a bed of said granular material particles through at least one outlet, the container comprising: a tapered discharge part having an inner wall converging to a bottom opening and to said at least one outlet at least one baffle located proximate to and/or at a bottom region of said tapered discharge part, said at least one baffle protrudes into said bed of granular material particles which forms a stagnant zone in said bed above said bottom opening, and the at least one baffle includes a baffle opening through which flows said granular material particles, and wherein said baffle opening has an area in cross section smaller than an area in cross section of the tapered discharge part where the at least one baffle is located and smaller than an area in cross section of the tapered discharge part below said baffle or smaller than an area in cross section of a discharge conduit connected to said discharge outlet.

2. The container according to claim 1, wherein said inner wall of the tapered discharge part is a conical wall.

3.-4. (canceled)

5. The container according to claim 1, wherein said at least one baffle is a monolithic annular plate having the baffle opening.

6. The container according to claim 1, wherein said at least one baffle includes a plurality of annular segments each separated from the other annular segments.

7. The container according to claim 1, wherein the the at least one baffle is a circular baffle.

8. The container according to claim 2, wherein the baffle opening is centered with respect to a vertical axis of the conical wall.

9.-11. (canceled)

12. The container according to claim 1, wherein said at least one baffle includes a baffle located at a bottom of the tapered discharge part of the container.

13. (canceled)

14. The container according to claim 1, wherein said at least one baffle includes a baffle located within a lower half portion of the tapered discharge part of the container.

15. (canceled)

16. The container according to claim 1, wherein the at least one baffle is a plurality of baffles each attached to the tapered discharge part of the container.

17. The container according to claim 1, further comprising a discharge rate regulating device.

18.-22. (canceled)

23. The container according to claim 1 wherein the container is a direct reduced iron (DRI) cooler.

24. The container according to claim 1, wherein said container is a shaft-type reactor for producing direct reduced iron (DRI).

25. The container according to claim 1, wherein said at least one baffle protrudes inwardly from the inner wall in a direction towards a central axis of the tapered discharge part, wherein a boundary between the stagnant zone formed above said at least one baffle and the bed of granular material particles flowing down to the at least one outlet extends upwardly to cover a zone of the bed where friction between the granular material particles and the inner wall of the tapered discharge part causes shaking or quaking of the container.

26. The container according to claim 2, wherein a ratio of a diameter D1 of said baffle opening to a diameter D2 of the cross section of the tapered discharge part at the point where the at least one baffle is located is in a range of 0.5 to 0.95.

27. The container according to claim 1, wherein a width of said at least one baffle protruding inside the bed of granular material particles is 10 to 100 times an average size of said granular material particles.

28. A device to decrease vibrations, shaking, quaking and/or noise of a container for storage or processing of granular material particles, the device comprising: a baffle including a baffle opening configured to allow a flow of said granular material particles, wherein said baffle opening has an area in cross section smaller than an area of a cross section of a tapered discharge part of the container where the baffle is located and smaller than an area of a cross section of the tapered discharge part below said baffle, or smaller than a cross section area of a discharge conduit connected to said discharge outlet.

29. The device according to claim 28, further wherein said baffle is an annular monolithic plate having the baffle opening.

30. The device according to claim 28, wherein said baffle is a plurality of annular segments each separated by a space from an adjacent one of the annular segments.

31. The device according to claim 28, wherein the baffle opening of the baffle is circular.

32.-34. (canceled)

35. A method to decrease vibrations, shaking, quaking and/or noise of a container for storing or processing granular material particles during discharge of a bed of said granular material particles through an outlet of the container, wherein said container comprises a tapered discharge part having an inner wall converging to said outlet, the method comprises: attaching at least one baffle having a baffle opening configured to pass said particles and protruding into said bend of granular material particles and towards a central axis of said tapered discharge part at a location within a lower half of said tapered discharge part to form at least one stagnant zone of particulate material in contact with the wall of the discharge part above said baffle, and wherein said baffle opening has an area in cross section smaller than an area of a cross section of the tapered discharge part where the baffle is located and smaller than an area in cross section of the tapered discharge part below said baffle or smaller than an area of a cross section of a discharge conduit connected to said discharge outlet.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIGS. 1 to 10 have been illustrated with reference to their relevant axes x, y and z and have been described in the detailed description in the same manner.

[0026] FIG. 1 shows a diagrammatic view of a generic bulk material container, illustrating a first embodiment of the invention wherein a ring-shaped device is installed at the discharge outlet of said container.

[0027] FIG. 2 shows a diagrammatic upper plan view of the container of FIG. 1.

[0028] FIG. 3 shows a diagrammatic view of a generic bulk material container illustrating a second embodiment of the invention wherein a ring-shaped device is attached to the wall of the lower part of said container above the discharge outlet.

[0029] FIG. 4 shows a diagrammatic upper plan view of the container of FIG. 3.

[0030] FIG. 5 shows a diagrammatic view of a third embodiment of the invention within a generic bulk material container similar to FIGS. 1 and 3, wherein a plurality of ring-shaped baffles are attached at the bottom and to the wall of the lower part of said container above the discharge outlet.

[0031] FIG. 6 shows a diagrammatic upper plan view of the container of FIG. 5.

[0032] FIG. 7 shows a schematic plan view of another embodiment of the ring shaped baffle of invention where the cross section of the tapered discharge part of the bulk material container is of oval shape.

[0033] FIGS. 8 and 8a show a schematic upper plan view of another embodiment of the invention where the tapered discharge part of the bulk material container are either of rectangular or polygonal pyramidal shape.

[0034] FIG. 9 shows a schematic perspective diagram of a monolithic embodiment of the ring shaped baffle of the invention for applications at low temperature.

[0035] FIG. 10 shows a schematic perspective diagram of another embodiment of the ring shaped baffle of the invention formed by annular segmented portions for applications where said baffle is in contact with granular material particles at high temperature.

[0036] FIG. 11 shows a diagrammatic view of a DRI cooler or DRI reactor incorporating an embodiment of the device of the present invention.

[0037] FIG. 12 shows a graph obtained by a computational simulator of the level of vibrations with and without the incorporation of a baffle according to the invention in a DRI shaft-type reactor.

[0038] FIG. 13 shows a plot of the level of vibrations actually measured with and without the incorporation of a baffle according to the invention in a DRI moving bed cooler.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

[0039] Although the invention is herein described as applied to a generic storage container of cylindrical body and conical tapered discharge part, and also an embodiment thereof is described of a process vessel for cooling DRI pellets by contact with a cooling gas circulating counter-currently to the continuous downward gravity flow of said DRI pellets, it will be understood that in its broader aspects the invention may also be applicable to other types of storage and process vessels or containers, silos, bins, hoppers, where a wide variety of granular materials are stored and/or processed, such as foodstuffs, grains, polymers, and granular material particles of products in many industrial processes.

[0040] In one aspect of the invention and with reference to FIG. 1, a granular material container is provided with a baffle located at the bottom precisely at the outlet of the tapered discharge part.

[0041] In another aspect of the invention and with reference to FIG. 3, a granular material container is provided with a baffle located above the outlet of the tapered discharge part.

[0042] In a further aspect of the invention according to FIG. 5, a granular material container is provided with a plurality of baffles located both at the outlet of the tapered discharge part and also above the outlet of said tapered discharge part.

[0043] In another additional aspect of the invention, the baffle has the shape of an annular plate with an opening through which the granular material particles flow.

[0044] In another aspect of the invention, the baffle has the shape of an oval plate with an opening through which the granular material particles flow. The opening may have also an oval shape.

[0045] In another aspect of the invention according to FIG. 8, the baffle has the shape of a rectangular plate with an opening through which the granular material particles flow. The opening may have also a rectangular shape. In another aspect according to the preceding one, the baffle has the shape of a polygonal plate with an opening through which the granular material particles flow. The opening may have also a polygonal shape.

[0046] In other aspect of the invention, for applications in containers comprising a conical discharge part and granular material particles at high temperature, the baffle is formed by a plurality of annular segmented portions that can be separately attached to the container wall leaving a gap between each other to allow expansion and contraction of said sections due to temperature changes.

[0047] In another aspect of the invention, the baffle has the shape of a linear bar which is attached to the each flat side wall of the container.

[0048] In other aspect of the invention, for applications in containers comprising a pyramidal discharge part having rectangular or polygonal shape and where the granular material particles reach high temperatures, the baffle is formed by a plurality of linear segments that can be separately attached to the container wall leaving a gap between each other to allow expansion and contraction of said segments due to temperature changes.

[0049] Referring to FIGS. 1 to 6, numeral 10 generally designates a generic container wherein a bed of granular material particles 12 moves downwardly by gravity, herein illustrated as of cylindrical shape having a cylindrical body 14 and a tapered discharge part generally designated with 15 has a conical inner wall 16 converging to an outlet 18 having a diameter indicated as D2. The tapered discharge part 15 having the conical wall 16 connects to a discharge conduit 20 having the same or larger diameter or dimensions than said outlet 18 by means of suitable flanges 22 and 24.

[0050] According to an embodiment of the invention, a ring-shaped baffle 26 is inserted, for example between flanges 22 and 24, which protrudes a surface 28 in the periphery of the bottom of the tapered discharge part 15.

[0051] The surface 28 of ring-shaped baffle 26 stops the downward flow of the material particles that are proximate and in contact with the conical inner wall 16 of the tapered discharge part 15, thus forming a stagnant zone 32 above the area defining the outlet 18. The boundary between the stagnant zone 32 and the granular material particles 12 flowing down may extend upwardly to a certain height that will be defined by the values of friction inter-particles and the friction between particles and the conical inner surface 16 of the tapered discharge part 15.

[0052] The granular material particles 12 flow down through the central bottom opening 34 of the baffle 26, located below the outlet 18, and continue flowing through a discharge conduit 20. The flow area for the granular material of conduit 20 is larger than the diameter D1 of baffle 26, so that a partial flow restriction effect is produced by the baffle 26 on the flow of granular material particles 12 in the area designated with 36.

[0053] In another embodiment of the invention shown in FIG. 3, a baffle 261 is attached, for example by welding, or any suitable fastening means which will be apparent to the skilled expert, to the inner surface 16 of the tapered discharge part 15, well above the discharge outlet 18. The ring-shaped baffle 261 has a central bottom opening 341 which forms a surface 281 in the periphery of the conical wall 16 of the tapered discharge part 15. The granular material particles 12 flowing down through the central bottom opening 341 continue flowing through the rest of the conical wall 16 of the tapered discharge part 15, the outlet 18 and conduit 20.

[0054] As shown in FIGS. 1 to 6, the ring-shaped baffles 26, 261, 263 and 264 are located at a position proximate to the outlet 18, preferably within the lower half portion of the height of the conical inner wall 16 of the tapered discharge part 15 and protrudes inwardly in the direction towards the central axis of the tapered discharge part 15 up to a certain radial distance so that the boundary lines between the stagnant zones 32, 321, 322, 323 and 324 formed above said baffles 26, 261, 262, 263 and 264, and the bed of granular material particles 12 flowing down to the central openings 34, 341, 342, 343 and 344 extend upwardly to cover the zone of the bed where the friction of the granular material particles 12 and the conical inner wall 16 of the tapered discharge part 15 causes the shaking or quaking of the container.

[0055] In some embodiments, the ratio of the diameter of the central opening D1 of the baffles 26 261, 262, 263 and 264 to the diameter D2 of said conical wall 16 of the tapered discharge part 15 at the point where the ring-shaped baffle is located, is in the range between 0.4 to 0.95.

[0056] In some embodiments as shown for instance in FIGS. 2, 4, 6, 7 and 8, the width W of the baffle protruding inside the bed of the granular material particles 12 is in the range from 10 to 100 times the average size of said particles.

[0057] Referring to FIG. 5, an embodiment of the invention is shown wherein a baffle 26 is placed at the bottom of the conical part 16 and also a plurality of baffles are placed above the outlet 18 in the conical part 16, designated by 262, 263, and 264. This embodiment may be applicable in those cases where the friction of the granular material particles against the wall of the container causes quaking or shaking of said container at a larger zone above the outlet 18.

[0058] In other embodiments of the invention, the container 100 is a DRI reactor, where the gas 40 is a reducing gas at high temperature, in the range from 850 C. to 1100 C.

[0059] The invention can be equally adapted for other hoppers and containers of cross sections other than cylindrical, such as polygonal, rectangular, oval or the like. In containers of the other mentioned geometries, the baffle of the invention will follow the contour of the perimeter of the tapered discharge part at the position where said baffle is located.

[0060] Referring to FIG. 7, a diagrammatic plan view of an embodiment of the invention is shown wherein the cross section of the tapered discharge part and its inner wall 161 has an oval shape. Equally the shape of the baffles 26, 261, 262, 263, 264, 266, the shape of the opening 34, 341, 342, 343, 344, 346 and finally the surface of the baffle 28, 281, 282, 283, 284, 286 may have the same shape according to this embodiment.

[0061] Referring to FIG. 8, a diagrammatic plan view of an embodiment of the invention is shown wherein the cross section of the tapered discharge part and its inner wall 162 have a rectangular shape. The baffles 267 (with the surface 287 forming the stagnant zone of material) and the bottom opening 347 have consequently the same rectangular shape of the container.

[0062] Referring to FIG. 8a, a diagrammatic plan view of an embodiment of the invention is shown wherein the cross section of the tapered discharge part and its inner wall 163 have a polygonal shape. The baffles 268 (with the surface 288 forming the stagnant zone of material) are then realized by linear segments by any suitable means known to the skilled expert. The bottom opening 348 has consequently the same shape of the container or baffles.

[0063] Referring to FIG. 9, a diagrammatic perspective view of a baffle 26, 261, 262, 263, 264 according to some embodiments of the invention is shown as a one-piece ring, typically made of steel, but it will be understood that said baffle may be made of any other suitable material as best fits for a particular application. The one-piece baffle 26, 261, 262, 263, 264, may be used in applications where the temperature changes of the granular material particles in contact with said baffle are not significant as to cause stresses or deformation of the baffle.

[0064] Referring to FIG. 10, for applications where the baffles 26, 261, 262, 263, 264, 266, and 269 are in contact with granular material particles at high temperatures, above about 100 C., for example when the baffle is used in DRI reactors or DRI coolers, where the particles in contact with said baffle may be in the range from 100 C. to 800 C., the baffle 26, 261, 262, 263, 264, 266 and 269 is formed by a plurality of annular segments 265 which may be attached to the inner wall 16 leaving spaces 70 between each other to allow expansion and contraction of the annular segments 265 due to changes in temperature. The number of annular segments may vary depending on the size and material of the baffle 26, 261, 262, 263, 264, 266 and 269. In some embodiments, the number of segments forming a baffle is 8.

[0065] It is also to be understood that, a segmented baffle as in FIG. 10 may be likewise applied to a linear segment, or linear segments, which can form a rectangular 267 or polygonal 268 baffle as in FIGS. 8 and 8a, where however for the sake of clarity of drawing a space between segments has not been illustrated.

[0066] Referring to FIG. 11, it is described another exemplary embodiment of the present invention, where it is shown a direct reduced iron (DRI) cooler 100. The direct reduced iron cooler 100 has, by way of example, a cylindrical upper part 149 where a bed of granular material particles 129 containing metallic iron are cooled by circulating a non-oxidizing gas 40 fed through a gas inlet 42. Hot cooling gas 44 is then withdrawn through a gas outlet 46. A bed of DRI granular material particles 129 are fed into the DRI cooler 100 at high temperature, in the range from about 400 C. to 800 C. through at least one conduit 48 and flow downwardly by gravity at a regulated rate by means of a regulating discharge device 50 for example a star-type rotary valve, a vibrating feeder or any other similar mechanism and are discharged at a lower temperature through conduit 52.

[0067] The DRI cooler 100 has a lower tapered discharge part 159 having an inner conical wall 169 converging to an outlet 189. Other mechanical components of the connections of the DRI cooler 100 with the discharge rate regulating mechanism and the discharge conduits, such as flanges and expansion joints are not shown for simplicity of the figure, however any appropriate combination of the elements described and specifically referenced in FIGS. 1 to 10 may be combined and used, as it will be apparent to the skilled expert in order to obtain and work the invention, in particular in reference to the most appropriate shape of the baffles, openings, dimensions and positioning within the container 100. In particular the baffle or baffles of the DRI cooler 100, due to the temperatures reached within the container may very well be those illustrated and described in FIG. 10.

[0068] In order to decrease the vibrations and quaking of the DRI cooler, a ring-shaped baffle 269 is placed at the bottom of the outlet 189 of the tapered discharge part 159, for example by means of suitable flanges (now shown). The ring-shape baffle 269 has the form of an annular plate with a central bottom opening 349 similarly to what has been described above for bottom openings 34 and 341 (in FIGS. 1 to 4) and which forms a flat surface 289 in the periphery of the conical wall 169 of the tapered discharge part 159 that prevents the pellets from flowing against the conical wall 169 of the tapered discharge part 159 forming a stagnant zone 329 of DRI granular material particles 129.

[0069] As an example of the effectiveness of the invention in reducing the intensity of vibrations, FIG. 12 shows a graph of a comparison between the magnitude of the vibrations, measured in mm/s obtained by a computational simulator of the flow of granular material particles in a DRI shaft-type reactor with and without the installation of a baffle according to the invention. Line 60 indicates the level of vibrations measured as a fraction of the acceleration of gravity (g) of the DRI reactor versus time in seconds. The intensity of vibrations reach levels of about 0.2 (g) without utilizing a baffle according to the invention. Line 62 indicates the level of vibrations after incorporation of the baffle of the invention showing a significant change to values below about 0.02 (g).

[0070] Another example of the effectiveness of the invention is shown in FIG. 13, where the level of vibrations actually measured in mm/s during the operation of a DRI cooler, indicated by numeral 64, decreased from levels reaching 40 mm/s to levels of less than 1 mm/s as indicated by numeral 66.

[0071] The invention herein described and claimed is a cost-competitive and effective method and apparatus to decrease vibrations, such as quaking and shaking as well as noise effects, known also as hooting, honking or howling, during the discharge of granular materials from silos, hoppers, bins, reactors and in general containers for storing or processing such granular material particles.

[0072] It is of course to be understood that the invention has been specified in detail only with respect to certain preferred embodiments thereof, and that a number of modifications and variations can be made without departing from the spirit and scope of the invention which is defined by the following claims.