METHOD OF CHARGING A COKE OVEN

Abstract

A method of charging a coke oven with coal includes the steps of charging coal in a coke oven chamber, whereby a heap of coal forms in the chamber; and leveling the heap of coal, where the leveling step includes: introducing a blasting end of a blasting pipe into the heap of coal, the blasting pipe being in communication with a pressurized gas storage vessel configured to release gas blasts; releasing at least one gas blast through the blasting end in the heap of coal in order to cause a leveling thereof; removing the blasting pipe from the chamber.

Claims

1. Method of charging a coke oven with coal, said method comprising the following steps: a) charging coal into a coke oven chamber, whereby a heap of coal forms in said chamber; b) leveling said heap of coal; wherein said leveling step b) comprises: introducing a blasting end of a blasting pipe into said heap of coal, the blasting pipe being in communication with a pressurized gas storage vessel configured to release gas blasts; releasing at least one gas blast through said blasting end in said heap of coal in order to collapse said heap under the blast impact force and cause a leveling thereof; removing the blasting pipe from said chamber.

2. The method according to claim 1, wherein the blasting pipe is plunged in the heap of coal through the upper surface of a conical heap of coal.

3. The method according to claim 2, wherein the blasting end of the blasting pipe is positioned in a region underneath the apex of the conical heap, preferably centrally.

4. The method according to claim 1, wherein the coal is charged loosely via a charging hole through the roof of said chamber, and the blasting pipe is plunged into said heap of coal in a vertical or oblique movement through said charging hole.

5. The method according to claim 1, wherein at step a) a plurality of conical heaps of coal are formed, and the leveling steps b) is carried out for each of said plurality of conical heaps.

6. The method according to claim 1, wherein the blasting end of the blasting pipe is introduced at a depth of between 0.5 and 1.5 m, underneath the apex of the conical heap.

7. A method according to claim 1, wherein the gas blast is released with a pressure between 5 and 15 bar.

8. Coke oven comprising: at least one coke oven chamber having a roof; and a device for leveling a heap of coal, said device comprising: a storage vessel with pressurized gas configured to release gas blasts; a blasting pipe with a connection port and a blasting end, said connection port being axially remote from said blasting end and being connected with said storage vessel; at least one blasting opening at said blasting end of said blasting pipe through which a blast of compressed gas can be released into a heap of coal for leveling the latter; a manipulator device configured for moving said blasting pipe, through said roof, between a rest position and a working position, in which said blasting end of said blasting pipe is positioned in a heap of coal.

9. Coke oven according to claim 8, wherein said storage vessel contains a predetermined volume of gas at a predetermined pressure, and comprises a rapid release valve with trigger mechanism that is configured to quickly release said volume of gas via a blow-out pipe, thus creating a gas blast.

10. Coke oven according to claim 8, wherein said blasting pipe is connected directly or indirectly to said storage vessel.

11. Coke oven according to claim 8, wherein the device is configured such that said blasting pipe can be moved relative to said storage vessel.

12. Coke oven according to claim 8, wherein the blasting end of the blasting pipe comprises a nozzle with at least one blasting orifice.

13. Coke oven according to claim 12, wherein the blasting nozzle extends in the axial direction of the blasting pipe and comprises a unique blasting orifice adapted to release gas blasts axially ahead of the blasting pipe.

14. Coke oven according to claim 12, wherein the blasting nozzle comprises a pair of blow tubes each deviating by a predetermined angle () from the axis of the blowing pipe for releasing blasts of compressed gas in two different directions, preferably symmetrical with respect to the axis of the blowing pipe.

15. Coke oven according to claim 14, wherein said predetermined deviating angle () is comprised between 20 and 90.

16. Coke oven according to claim 14, wherein the blow tubes are straight tubes and define two blasting directions forming an angle of about 70 or 90.

17. Coke oven according to claim 13, wherein the blasting nozzle comprises a pair of blow tubes with curved portions, and the blasting orifices are aligned along opposite blasting directions, in particular forming an angle of 180.

18. Coke oven according to claim 14, wherein the nozzle further comprises a V-shaped frontal guide, the apex thereof pointing ahead of the first and second blasting nozzles in order to ease the introduction of the blasting pipe into the heap of coal.

19. Coke oven according to claim 8 further comprising a tightening ring that is configured to cooperate with a charging hole in said roof of said coke oven, in order to close said charging hole during blasting.

20. The method according to claim 6, wherein the blasting end of the blasting pipe is introduced at a depth of about 1 m underneath the apex of the conical heap.

21. The method according to claim 8, wherein the gas blast is release with a pressure between 5 and 10 bar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Further details and advantages of the present disclosure will be apparent from the following detailed description of several not limiting embodiments with reference to the attached drawings, wherein:

[0053] FIG. 1 is a front view of a leveling device according to one embodiment of the present disclosure;

[0054] FIG. 2 is a detail view of the blasting end of the blasting pipe in FIG. 1;

[0055] FIG. 3 and FIG. 4 are views of other possible nozzle designs;

[0056] FIG. 5 to FIG. 8 are sketches illustrating the use of the present device for leveling heaps of coal in coke oven chambers.

DETAILED DESCRIPTION

[0057] FIG. 1 shows an embodiment of the present device 10 for leveling a heap of coal in a coke oven chamber of a coke oven battery in accordance with the present disclosure. The device 10 will first be described in relation to FIGS. 1 to 4; and the use thereof in the context of the charging of coke ovens will be explained further below with reference to FIGS. 5 to 8. The device 10 mainly comprises a storage vessel 14 for a pressurized gas, preferably air, fluidly connected with a blasting pipe 16, which has a connection end 18 with an inlet port 19 and a blasting end 20. In the embodiment, the blasting pipe 16 is a straight, rigid pipe defining an internal gas passage 23 extending between the inlet port 19 (at one end of the pipe 16) and the blasting end 20, at the axially opposite extremity of the blasting pipe 16. As can be seen, the blasting pipe 16 has its inlet 19 connected to an outlet 21 of the storage vessel 14, whereby both elements are in fluid communication.

[0058] At the blasting end 20, air blasts are emitted through one or more openings, here a pair of openings 22.sub.1 and 22.sub.2.

[0059] One can see on FIG. 1 a first dotted line that represents the upper surface 24 of a heap of coal. One will recognize here the shape of a cone. Indeed, as explained in the background art section, when a coke oven is filled with coal, a conical heap forms below each charging hole in the roof, according to the angle of repose of the coal particles. Seen more globally, the global shape of the coal heap in the coke oven is comprised of a base layer of coal, with a plurality of conical heaps (or peaked piles) on top. The upper part of the loaded heap thus has a profile with spaced top triangles, forming peaks and valleys. Such heap shape needs to be leveled, i.e. flattened.

[0060] The blasting end 20 of the blasting pipe 16 is designed to be introduced in the heap of coal, in particular in a conical heap 25, as represented, and the device 10 is configured to discharge/emit one or more blasts of compressed air through the openings 22.sub.1 and 22.sub.2 into the heap of coal 25, in order to collapse the conical heap and hence cause a leveling of the heap of coal.

[0061] The second dotted line in FIG. 1 represents the upper surface profile 26 of the leveled heap of coal, after blasting. The coal heap in the coke oven chamber can thus be efficiently leveled by way of air/gas blasting, which can easily be operated at each charging hole of a coke oven.

[0062] It may be noticed that in practice, the device 10 is conveniently associated with a manipulator device, schematically represented at 27 in FIG. 5, that is typically configured to move the blowing pipe 16 between a rest position and a working position, in which said blasting end of said blasting pipe is positioned in a heap of coal. The design of the manipulator device requires mechanisms to at least move the blowing pipe 16, respectively the device 10, along the vertical direction, to introduce the blowing pipe into the heap of coal via the charging hole, and to remove it. Conveniently, the manipulator device is also configured to move the device 10 horizontally, to allow alignment with the charging hole and clearing the region above the charging hole. The construction of such manipulator is not the focus of the present disclosure and will therefore not be further described. Those skilled in the art may devise a variety of appropriate manipulator mechanisms based on hydraulic cylinders, toothed racks, etc.

[0063] It may however be noticed that in the present embodiment, the blasting pipe 16 is directly connected to the storage vessel 14, and the assembly of the blasting pipe 16 and storage vessel 14 is moved downward and upward as a whole. This may be different in other embodiments. The blasting pipe can be indirectly connected to the storage vessel, e.g. via intermediate piping. Also, in some cases it may be desirable to be able to manipulate the blasting pipe with respect to the storage vessel. The blasting pipe and/or the intermediate piping may include an articulation, designed to allow movement of the intermediate piping while ensuring fluid/gas communication between the storage vessel and the blasting pipe.

[0064] Preferably, the storage vessel 14 is configured as a conventional air blaster (or air/gas cannon). Accordingly, the storage vessel conventionally consists of a pressurized reservoir comprising a quick release valve with trigger mechanism (not visible in the drawinginside vessel 14), that allows instantly releasing the compressed air contained in the storage vessel and thereby achieve a blast, called the impact force, that forms a kind of explosing spread of gas/air. The quick release valve (inside reservoir 14not seen) is typically a fast opening, large surface valve arranged at the transition between the storage vessel and a blow-out tube. The quick release valve is selectively actuated by way of the trigger mechanism. In the shown embodiment, the blow out tube extends mainly inside the storage vessel 14 and protrudes shortly out of the storage vessel, ending with a flange 28. Blasting pipe 16 is fixed by its connection end 18 against flange 28, by a corresponding flange 31 surrounding the inlet 19. The blasting pipe 16 is thus in fluid communication with the blow-out tube, respectively the outlet 21, of the storage vessel 14. In other embodiments, the blow out tube and blasting pipe may be integral. Reference sign 29 indicates the inlet side of the storage vessel 14, comprising valving and piping with a pressurized gaz inlet port.

[0065] Such gas cannons are well known and any appropriate type of gas cannon may be used. For example, in the context of the disclosure one may use a VSR Blaster, available from the company VSR Industrietechnik GmbH (Duisburg, Germany). The storage vessel may have a volume of 25 L, 50 L or above. The storage pressure of the gas contained in the storage vessel may be between 5 and 15 bar, in particular between 5 and 10 bar. In practice, the gas may be air, and it is convenient to connect the storage vessel 14 to the air network of the plant. Operation with gases other than air can be considered, e.g. with neutral gas, in particular nitrogen.

[0066] Also to be noted in FIG. 1 is a radial, tightening ring 32 surrounding the blasting pipe 16, which has an internal diameter matching that of the blasting pipe 16 and that can be slideably moved there along. This ring 32 is configured to form a cover cooperating with the inlet section of a charging hole 62 of a coke oven (see FIG. 6), in order to close the charging hole 62 through which the blasting pipe 16 is inserted when the device 10 is in position ready for blasting. The cover 32 thus advantageously allows tightly closing the charging hole 62 during the blasting of the heap, avoiding emission of fines outside from the coke oven chamber.

[0067] As visible in FIG. 1, the blasting end 20 of the blasting pipe 16 conveniently ends with a nozzle 40. In the shown embodiment, the nozzle 40 is a double blow nozzle, i.e. it comprises two discharge orifices 22.sub.1, 22.sub.2. The nozzle 40 is fixed at the tip of the blasting pipe 16, but could also be integral therewith.

[0068] As can be seen in more detail in FIG. 2, nozzle 40 has an inlet section 44 in axial continuation of the internal gas passage 23 of the blasting pipe 16, which communicates with two blow tubes 42.sub.1 and 42.sub.2 ending each with a respective blow orifice 22.sub.1, 22.sub.2. The inlet section 44 of nozzle 40 is of circular cross-section (section B-B). The two blow tubes 42.sub.1 and 42.sub.2 are straight and of circular cross-section; they extend along a respective axis D or D that defines the blow direction. The blow tubes 42.sub.1 and 42.sub.2 are symmetric relative to the longitudinal axis L of the blasting pipe. In other words, the axis D, D of each blow tube deviates from axis L by an angle , whereby an angle 2a exists between the axes D and D of the two blow tubes 42.sub.1 and 42.sub.2.

[0069] Nozzle 40 is thus designed to emit gas blasts ahead of the blasting pipe and to the side according to angle . The angle may be selected in the range from 20 to 90, preferably between 35 and 90. In particular, angle may be equal to 35, 45, 60 and 90. In the embodiment shown in FIG. 2, =35.

[0070] Turning to FIG. 3, an alternative nozzle design is shown. The nozzle 240 comprises an inlet section in fluid communication with the blasting pipe 16 and in axial continuation therewith. Here also the inlet stream divides into two blow tubes with respective orifices. As can be seen, blow tubes 242.sub.1 and 242.sub.2 comprise a curved tube section and end with a straight section 243 defining a blasting direction forming an angle of 90 (as indicated by axes D and D) with the axial direction L of the blasting pipe.

[0071] As can be seen in FIG. 3, in this variant the inlet section 244 preferably has a flattened cross-section (D-D) that matches the end portion of the blasting pipe (then of similar shape). The blow orifices 222.sub.1 and 222.sub.2 are however of circular cross-section, since they are defined by the straight sections 243 (of circular cross-section E-E).

[0072] Advantageously, a frontal guide 250 is mounted on the front side of the nozzle 240. The frontal guide 250 is a V-shaped metallic element. Its apex points away from the blow tubes 242 in axial direction L. Frontal guide 250 is designed to facilitate the introduction of the blasting pipe into the heap of coal.

[0073] In embodiments, the flow cross-section of the inlet pipe 144 and 244 is less than 200 cm.sup.2, preferably between 50 cm.sup.2 and 100 cm.sup.2. The flow cross-section of the blow tubes 142.sub.2 and 242.sub.2 at their outlet is below 100 cm.sup.2, preferably between 25 cm.sup.2 and 50 cm.sup.2.

[0074] FIG. 4 shows another design possibility, where the end portion of the blasting pipe itself forms the nozzle 142, with a single discharge orifice. The blasting pipe, of circular cross-section, is simply open in axial direction L at its tip: the discharge opening 122 is thus in a plane perpendicular to axis L. With such blasting nozzle 142, the blast is emitted uniquely ahead, i.e. in the axial direction L, of the blasting pipe 16. The cross-section of opening 122 may be less than 200 cm.sup.2, and preferably comprised between 50 cm.sup.2 and 100 cm.sup.2.

[0075] It remains to be noted that in the presently shown embodiments, the blasting pipe 16 is a straight pipe. Depending on the design of the coke oven battery, the length of the blasting pipe may vary between 1 and 6 m, in particular with lengths about 2, 3, 4 or 5 m. The nominal diameter may be between 80 and 120 mm, in particular about 100 mm. In alternative embodiments, other shapes may be considered for the blasting pipe. The above mentioned dimensions are convenient for operation with conventional coke ovens, where the charging hole inlet section may have a diameter up to 500-600 mm. Accordingly, the cover ring 32 may have a corresponding outer diameter. These are only exemplary values and should not be construed as limiting.

[0076] FIG. 5 to FIG. 8 schematically illustrate one embodiment of the present method of charging a coke oven 60 with coal. The method is advantageously carried out using the above described device 10.

[0077] In FIG. 5, reference sign 60 generally designates a coke oven comprising a roof 64 and a coke oven chamber 65. As it will be understood, the figure shows only a part of the coke oven, below one charging hole 62. The coke oven chamber 65 will typically comprise several charging holes. Reference sign 70 generally designates a heap of coal. The coal has been loosely charged into the chamber 65, by gravity via the charging hole 62. The coal particles may typically be fine coal as conventionally used for blast/shaft furnaces. The coal may namely have a grain size below 10 mm, and even below 5 mm. For example, in a batch of coal loaded in the coke oven, a typical grain size distribution would comprise between 10 and 20 wt. % coal particle above 3.15 mm, and about 40 to 60 wt. % coal particles below 1 mm, with a majority in the 500 m to 1 mm range. These are only exemplary values and should not be construed as limiting.

[0078] At the moment represented in FIG. 5, the step of charging the coke oven chamber with coal is finished. A heap of coal 70 has been formed in the chamber. It comprises base layer 71 of coal and a conical heap 72 (peaked pile) of coal, represented as a triangle, exists below each charging hole 62, typically laying over the base coal layer 71 (i.e. below triangle) as it is known to the skilled person and explained above. The device 10 is in a position ready for introduction into the coke oven, here referred to as rest position. The blasting pipe 16 is aligned vertically with the centre of the charging hole 62.

[0079] FIG. 6 illustrates a second step of the method: the device 10 is lowered into the coke oven chamber 65 in order to introduce the blasting end 20 of the blasting pipe 16 into the heap of coal 70, preferably to the center of the peaked pile of coal 70. This is simply done by a vertical movement of the device 10. The blasting end 20 with the discharge orifices is positioned in a region 74 underneath the apex 76 formed by the heap cone 72. The tip of blasting end 20, respectively the nozzle 40, may hence be submerged by a depth of at least 0.5 m, e.g. between 0.5 and 1.5 m, and preferably about 1 m, underneath the apex 76 of the heap cone. This is here referred to as the working position.

[0080] In the third step (shown in FIG. 7), one blast of compressed gas has been emitted through the blasting end 20 of the blasting pipe 16. The impact force has caused the triangular coal pile 72 to collapse, resulting in a leveling (flattening) of the coal heap 70 inside the coke oven chamber 65, as shown in the Figure. More than one blast may be released, if necessary.

[0081] One may note the cover 32 that has been slid along the blasting pipe 16 to be positioned at the entrance of the charging hole 62, in order to substantially close the latter during blasting and minimize emissions of dust into the atmosphere.

[0082] Finally, the device is moved upward in order to remove the blasting pipe 16 from the chamber 65, see FIG. 8.

[0083] The leveling procedure shown here with respect to FIGS. 5 to 8 is typically repeated for each single coked oven of the battery. For each coke oven, the operation is carried out for each charging hole, i.e. for each peaked pile formed during charging. The leveling can be carried sensibly out concurrently for each charging hole with a set of devices 10; or the same device 10 is used in each charging hole, one after another. With a properly designed gas blast system (blasting pipe as well pressurized storage vessel volume and pressure) it is possible to collapse a heap of coal with a single blast. The disclosure thus proves extremely efficient and expedient, which is of benefit for the overall coke oven management.