CA2310022A1 - Device for withdrawing lumpy material - Google Patents
Device for withdrawing lumpy material Download PDFInfo
- Publication number
- CA2310022A1 CA2310022A1 CA002310022A CA2310022A CA2310022A1 CA 2310022 A1 CA2310022 A1 CA 2310022A1 CA 002310022 A CA002310022 A CA 002310022A CA 2310022 A CA2310022 A CA 2310022A CA 2310022 A1 CA2310022 A1 CA 2310022A1
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- CA
- Canada
- Prior art keywords
- shaft furnace
- screw conveyors
- axes
- furnace
- section
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B1/00—Shaft or like vertical or substantially vertical furnaces
- F27B1/10—Details, accessories, or equipment peculiar to furnaces of these types
- F27B1/21—Arrangements of devices for discharging
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B13/00—Making spongy iron or liquid steel, by direct processes
- C21B13/02—Making spongy iron or liquid steel, by direct processes in shaft furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D3/00—Charging; Discharging; Manipulation of charge
- F27D3/08—Screw feeders; Screw dischargers
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Furnace Charging Or Discharging (AREA)
- Screw Conveyors (AREA)
- Manufacture Of Iron (AREA)
- Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
Abstract
The invention relates to a device for withdrawing lumpy material, especially lumpy material containing iron oxide and/or sponge iron, from a shaft furnace, especially a direct reduction shaft furnace. The withdrawal device consists of worm conveyors which protrude into the shaft furnace over the floor of the same. A number of worm conveyors are aligned along axes. The projection of said axes onto the horizontal cross-sectional surface of the shaft furnace or the imaginary extensions of the projection of the axes forms secants of the horizontal cross-sectional surface of the shaft furnace. Said axes extend at a distance from the central point of the cross section of the furnace.
Description
Arrangement for discharging lump material The invention relates to an arrangement for discharging lump material, particularly lump material containing iron oxide and/or sponge iron and coming from a shaft furnace, particularly from a direct reduction shaft furnace, wherein the discharging device is comprised of screw conveyors projecting into the shaft furnace above the bottom of the shaft furnace.
Many discharging devices of the kind described above are known from prior art.
As a rule, they are used for discharging lump material from a shaft furnace, for example, from a direct reduction shaft furnace, lump material meaning completely or partially reduced sponge iron which may still contain a low share of iron oxide, depending on the degree of metallization.
A shaft furnace where such a discharging device is used is usually essentially designed as a cylindrical hollow body and contains a packed bed of lump material containing iron oxide and/or sponge iron, with the material containing iron oxide being charged into the upper part of the shaft furnace, possibly together with additives such as lime or dolomite.
A reduction gas coming, for example, from a melter gasifier is injected into the shaft furnace and, thus, into the solids bed through several inlet ports arranged along the circumference of the shaft furnace in the area of the lower third of the shaft furnace. The hot, possibly dust-laden reduction gas flows upwards through the solids bed, thereby completely or partially reducing the iron oxide of the bed to sponge iron.
The completely or partially finish-reduced sponge iron is withdrawn from the shaft furnace through the discharging device located above the bottom of the shaft furnace.
As a rule, this discharging device is comprised of a radial arrangement of radially (referred to the shaft furnace) conveying screw conveyors, with the axes of the screw conveyors lying in a horizontal cross-sectional plane of the shaft furnace.
The zone located in the area of the shaft bottom where the discharging device is installed is to be comprised of a maximum active discharge area in order to ensure that the bulk material descends as uniformly as possible and to achieve continuous movement and mixing of the material in the reaction zone.
c..o.n~.n.. c ~.."",..nymmvwr.m7»n ms The radial arrangement of the screw conveyors, however, is disadvantageous in some respect in that partial areas of the bulk material in the plane of the screw conveyors cannot be covered by the latter and, therefore, unmoving zones with very steep inner angles of repose are formed above these inactive areas. These zones, which are referred to as "dead man", have the disadvantage that a percentage of the reaction volume becomes partially inactive, active volume meaning the region of a shaft furnace where the desired gas-solid reactions take place. Part of the reaction volume of the shaft furnace thus is lost in that a nearly unmoving bed is formed therein.
As a result, takings and agglomerates may form in these regions due to the long dwelling times of the ores or of the reduced ores, respectively, which have a negative effect on the material flow and consequently even further reduce the material reaction and, thus, productivity.
The prior-art an-angement of screw conveyors essentially features two zones above which "dead man" is formed, i.e. the central region which is only insufficiently covered by the radially arranged screw conveyors and remains nearly unmoving and the zone formed by the wedge-shaped regions each located between two adjacent screw conveyors, wherein the bulk pyramids building up above these inactive zones impede the solids flow, on the one hand, and build up to a level that the gas inlet ports for the reduction gas are concealed by the bulk material building up so .that a relatively gas-impermeable packed bed is locally formed owing to the dust freight of the reduction gas deposited in the bulk material. As a result, the necessary homogeneous gas distribution in the shaft furnace does not take place.
Another disadvantage of the prior-art arrangement of screw conveyors lies in the fact that maximum possible loading of the bearing of the axes results from the horizontal alignment of the axes of the screw conveyors. A typical shaft furnace has a radius of three to four meters, for example, in the area of the discharging device. The screw conveyors, which essentially are of the same length and usually cantilevered, i.e.
supported in the circumference of the shaft furnace, are loaded by their dead weight as well as by a large part of the packed bed located in the shaft furnace, which has a height of more than 20 meters.
GweW rW G~dw.vr.~pay1771rmc Owing to the unfavorable lever action, the load on the bearing of the axes is enormously high and, accordingly the bearings are susceptible to failure, which results in frequent and expensive repair.
~~ 6 EP-B-0 y1~ 679 describes screw conveyors for moving and discharging solid particles into and out of a shaft furnace. These screw conveyors are radialty arranged, cantilevered and of equal length. Although the dead comers between adjacent screws are minimized by wedge-shaped baffles, the build-up of "dead man" cannot be prevented. The problem regarding the susceptibility to failure, which arises from the bearing of the screw conveyor, is not dealt with.
EP-B-0 085 290 discloses arrangements of short conical screws, which are supported both in a tapered baffle located in the center and in the circumference of the shaft fumar,.e. The tapered baffle located in the center is to prevent the build-up of the central "dead man." Wedge-shaped baffles tapering upwards are located between adjacent screw conveyors so that each screw conveyor is located in a kind of trough.
However, it is known that any kind of stationary baffle in a reduction shaft furnace that constitutes a reduction of the free furnace cross section from the point of viev~i of the bulk material promotes bridging, i.e. partial sintering together and caking of adjacent particles within the bulk material.
On the other hand, channels may form directly above the screw conveyors, i.e.
in areas where the subsidence rate of the bulk material is particularly high owing to the discharge achieved by the screw conveyors. Since the reduction gas preferably flows in these channels, the necessary homogeneous gas distribution in the shaft furnace is no longer achieved.
Consequently, none of the arrangements of screw conveyors and/or baffles known from prior art is capable of preventing the formation of bulk pyramids refer-ed to as "dead man" in the center of the shaft furnace and between two adjacent screw conveyors each on the inner edge of the shaft furnace or to prevent it to an extent that the bulk materials subsides largely uniformly.
C,rowdrn n G W ..wyww~y,~,n,m, W 177Y1 e:
Many discharging devices of the kind described above are known from prior art.
As a rule, they are used for discharging lump material from a shaft furnace, for example, from a direct reduction shaft furnace, lump material meaning completely or partially reduced sponge iron which may still contain a low share of iron oxide, depending on the degree of metallization.
A shaft furnace where such a discharging device is used is usually essentially designed as a cylindrical hollow body and contains a packed bed of lump material containing iron oxide and/or sponge iron, with the material containing iron oxide being charged into the upper part of the shaft furnace, possibly together with additives such as lime or dolomite.
A reduction gas coming, for example, from a melter gasifier is injected into the shaft furnace and, thus, into the solids bed through several inlet ports arranged along the circumference of the shaft furnace in the area of the lower third of the shaft furnace. The hot, possibly dust-laden reduction gas flows upwards through the solids bed, thereby completely or partially reducing the iron oxide of the bed to sponge iron.
The completely or partially finish-reduced sponge iron is withdrawn from the shaft furnace through the discharging device located above the bottom of the shaft furnace.
As a rule, this discharging device is comprised of a radial arrangement of radially (referred to the shaft furnace) conveying screw conveyors, with the axes of the screw conveyors lying in a horizontal cross-sectional plane of the shaft furnace.
The zone located in the area of the shaft bottom where the discharging device is installed is to be comprised of a maximum active discharge area in order to ensure that the bulk material descends as uniformly as possible and to achieve continuous movement and mixing of the material in the reaction zone.
c..o.n~.n.. c ~.."",..nymmvwr.m7»n ms The radial arrangement of the screw conveyors, however, is disadvantageous in some respect in that partial areas of the bulk material in the plane of the screw conveyors cannot be covered by the latter and, therefore, unmoving zones with very steep inner angles of repose are formed above these inactive areas. These zones, which are referred to as "dead man", have the disadvantage that a percentage of the reaction volume becomes partially inactive, active volume meaning the region of a shaft furnace where the desired gas-solid reactions take place. Part of the reaction volume of the shaft furnace thus is lost in that a nearly unmoving bed is formed therein.
As a result, takings and agglomerates may form in these regions due to the long dwelling times of the ores or of the reduced ores, respectively, which have a negative effect on the material flow and consequently even further reduce the material reaction and, thus, productivity.
The prior-art an-angement of screw conveyors essentially features two zones above which "dead man" is formed, i.e. the central region which is only insufficiently covered by the radially arranged screw conveyors and remains nearly unmoving and the zone formed by the wedge-shaped regions each located between two adjacent screw conveyors, wherein the bulk pyramids building up above these inactive zones impede the solids flow, on the one hand, and build up to a level that the gas inlet ports for the reduction gas are concealed by the bulk material building up so .that a relatively gas-impermeable packed bed is locally formed owing to the dust freight of the reduction gas deposited in the bulk material. As a result, the necessary homogeneous gas distribution in the shaft furnace does not take place.
Another disadvantage of the prior-art arrangement of screw conveyors lies in the fact that maximum possible loading of the bearing of the axes results from the horizontal alignment of the axes of the screw conveyors. A typical shaft furnace has a radius of three to four meters, for example, in the area of the discharging device. The screw conveyors, which essentially are of the same length and usually cantilevered, i.e.
supported in the circumference of the shaft furnace, are loaded by their dead weight as well as by a large part of the packed bed located in the shaft furnace, which has a height of more than 20 meters.
GweW rW G~dw.vr.~pay1771rmc Owing to the unfavorable lever action, the load on the bearing of the axes is enormously high and, accordingly the bearings are susceptible to failure, which results in frequent and expensive repair.
~~ 6 EP-B-0 y1~ 679 describes screw conveyors for moving and discharging solid particles into and out of a shaft furnace. These screw conveyors are radialty arranged, cantilevered and of equal length. Although the dead comers between adjacent screws are minimized by wedge-shaped baffles, the build-up of "dead man" cannot be prevented. The problem regarding the susceptibility to failure, which arises from the bearing of the screw conveyor, is not dealt with.
EP-B-0 085 290 discloses arrangements of short conical screws, which are supported both in a tapered baffle located in the center and in the circumference of the shaft fumar,.e. The tapered baffle located in the center is to prevent the build-up of the central "dead man." Wedge-shaped baffles tapering upwards are located between adjacent screw conveyors so that each screw conveyor is located in a kind of trough.
However, it is known that any kind of stationary baffle in a reduction shaft furnace that constitutes a reduction of the free furnace cross section from the point of viev~i of the bulk material promotes bridging, i.e. partial sintering together and caking of adjacent particles within the bulk material.
On the other hand, channels may form directly above the screw conveyors, i.e.
in areas where the subsidence rate of the bulk material is particularly high owing to the discharge achieved by the screw conveyors. Since the reduction gas preferably flows in these channels, the necessary homogeneous gas distribution in the shaft furnace is no longer achieved.
Consequently, none of the arrangements of screw conveyors and/or baffles known from prior art is capable of preventing the formation of bulk pyramids refer-ed to as "dead man" in the center of the shaft furnace and between two adjacent screw conveyors each on the inner edge of the shaft furnace or to prevent it to an extent that the bulk materials subsides largely uniformly.
C,rowdrn n G W ..wyww~y,~,n,m, W 177Y1 e:
According to prior art, the excessive strain on the bearing of the screw conveyors can only be reduced if the screw conveyors are supported both in the circumference and in the center of the shaft furnace. Therefore, the central region of the shaft furnace is no longer covered by the screw conveyors.
Accordingly, the technical problem of the invention is to provide an arrangement for discharging lump material from a shaft furnace which avoids the disadvantages of prior art. Particularly the formation of "dead man" both in the center of the shaft furnace and between two adjacent screw conveyors each on the inner edge of the shaft furnace is to be avoided or reduced to an extent that the gas inlet ports for the reduction gas are no longer concealed, on the one hand, and that the reaction material subsides largely uniformly, on the other hand. At the same time, the strain on the bearings of the axes of the screw conveyors is to be reduced as far as possible.
This technical problem is solved by the arrangement according to the invention which is characterized in that a number of screw conveyors are aligned along axes whose projection onto the horizontal cross-sectional area of the shaft furnace or the mathematical production of the projection of these axes form secants of the horizontal cross-sectional area of the shaft furnace, these axes running off the center of the furnace cross section.
The screw conveyors arranged according to the invention effectively prevent the build-up of bulk pyramids on the inner edge of the shaft furnace. Thus, the reaction material subsides uniformly and the dwelling times of the ores or the reduced ores, respectively, in the shaft furnace are no longer different. Moreover, this arrangement decreases the load of the bearing of the axes and essentially reduces the frequency of repair.
According to the invention, the screw conveyors are arranged in a way that the axes are not aligned to the center of the shaft furnace but point past the center of the shaft furnace as it were, axis meaning both the geometric center line of a screw conveyor, unless otherwise designated, and the mathematical production of this line up to the point of intersection with the inner generated surface of the shaft furnace. The axis of the screw conveyor is thus skew to the center line of the shaft furnace running vertically through the shaft furnace.
~..o.b.., - ~ n..w...P..~,.,.~.n""~.W",.~.,.~., Another advantage of the invention is that the skew screw conveyors exert a torque on the bulk material in the shaft furnace. Accordingly, owing to the discharge achieved by the screw conveyors, the bulk material descends not only by gravity but moves essentially spirally in the area of the skew screw conveyors within the shaft furnace.
This additional spiral movement leads to an intimate mixing of the bulk materials and effectively prevents the formation of takings and channels.
The normal distance of tf~e axis to the center fine of the shaft furnace may be equal or different for all screw conveyors of one plane of screw conveyors. This skew arrangement of screw conveyors reduces the wedge-shaped area between two adjacent screw conveyors above which bulk pyramids may build up.
According to another feature of the invention, the axes of the screw conveyors are inclined upwards or downwards in relation to the horizontal line.
Preferably an angle of up to 70° is included by the axes of the screw conveyors and the horizontal line, an angle of inclination of 30° to 50° being particularly preferred.
On the one hand, this has the advantage that the screw conveyors are less subjected to bending stresses but rather, to tensile or compression stresses, depending on the direction of inclination. Moreover, an additional portion of the bulk pyramids is removed:
According to a preferred embodiment, the screw conveyors of the arrangement according to the invention are an-anged in two superposed level sections, one of these sections, for example, the lower one, showing an actually known radial, horizontal arrangement of screw conveyors. In the second section, the screw conveyors are inclined according to the invention, for example, downwards and aside.
~..~.~,- ~ °......~...,~.n"~".m,~.~.,.n., According to another embodiment, both level sections have an equally large number of screw conveyors, wherein the openings for the screw conveyors into the shaft furnace of both level sections are uniformly distributed over the circumference of the shaft furnace and wherein the openings of the screw conveyors into the shaft furnace of the upper level section are offset against the openings of the lower level section by up to half the central angle between two adjacent openings in circumferential direction.
This arrangement combines the advantages of the radial arrangement as well as of the skew arrangement of screw conveyors. A radial arrangement of screw conveyors is suitable for discharging material from the center of the shaft furnace but involves the known problems regarding the bulk pyramids on the inner edge of the shaft furnace.
A plane of screw conveyors located above or below, however, is suited to remove these bulk pyramids on the inner edge of the shaft furnace or to prevent their formation.
According to another embodiment of the arrangement according to the invention, two or more screw conveyors supported on both sides in the circumference of the shaft furnace are arranged in parallel and in a horizontal plane. However, an arrangement of parallel screw conveyors cannot cover the entire furnace cross section. Therefore, one group each of at least two screw conveyors is preferably provided on both sides of the parallel screw conveyors, the axes of the screw conveyors of each group being aligned in a way that they show a point of intersection off the center of the furnace cross section and the point of intersection of the axes of one group of screw conveyors each being located in the same half of the furnace cross section as the screw conveyors of the group proper.
An arrangement of screw conveyors of such design allows to essentially cover the entire furnace cross section and, thus, to achieve a uniform discharge of the bulk material.
In the following, the an-angement according to the invention is explained in greater detail by the embodiments represented in the drawings, Fig. 1 to Fig. 3.
Fig. 1: Schematic shaft furnace, screw conveyors in two level sections, wherein the screw conveyors of the upper level sections are inclined according to the invention.
Fig. 2: Horizontal section through the shaft furnace, top view of screw conveyors.
~....d..,. ~ d..,...,a...w...a."...~".....,.~, Fig. 3: Alternative embodiment: Combined continuous, parallel screws with one group each of three screw conveyors on both sides of the parallel screws, top view.
Fig. 1 displays the side elevation of a vertical section through shaft furnace 1 containing packed bed 2 of lump material, which is discharged from the shaft furnace by means of schematically represented screw conveyors 3, 4. Screw conveyors 3, 4 are arranged in two level sections 5, 6, with screw conveyors 4 of lower level section 6 showing a known radial arrangement, their axes thus being located in one plane. Screw conveyors 3 of upper level section 5 are inclined upwards according to the invention, angle a of approximately 40° being included by the axes of screw conveyors 3 and the horizontal line.
Fig. 2 displays the top view of a horizontal section through shaft furnace 1, showing the radial an-angement of screw conveyors 4 of lower level section 6. The axes of screw conveyors 3 of upper level section 5 are inclined aside by angle j3 of approximately 20° in relation to those of a radial arrangement. Openings 8 of screw conveyors 3 into shaft furnace 1 of upper level section 5 are offset against openings 7 of screw conveyors 4 into shaft furnace 1 of lower level section 6 by approximately one third of central angle y between two adjacent openings, which is approximately 60°.
Fig. 3 displays the top view of an alternative embodiment, wherein three continuous, parallel screw conveyors 9 each are supported on both sides in cylinder jacket 10 of shaft furnace 1. One group 11, 12 each of short screw conveyors is provided on both sides of screw conveyors 9 arranged in parallel, whose axes show one point of intersection each which is located off the center of the shaft furnace. This arrangement of screw conveyors 9, 11, 12 ensures a uniform discharge of bulk material from shaft furnace 1.
Accordingly, the technical problem of the invention is to provide an arrangement for discharging lump material from a shaft furnace which avoids the disadvantages of prior art. Particularly the formation of "dead man" both in the center of the shaft furnace and between two adjacent screw conveyors each on the inner edge of the shaft furnace is to be avoided or reduced to an extent that the gas inlet ports for the reduction gas are no longer concealed, on the one hand, and that the reaction material subsides largely uniformly, on the other hand. At the same time, the strain on the bearings of the axes of the screw conveyors is to be reduced as far as possible.
This technical problem is solved by the arrangement according to the invention which is characterized in that a number of screw conveyors are aligned along axes whose projection onto the horizontal cross-sectional area of the shaft furnace or the mathematical production of the projection of these axes form secants of the horizontal cross-sectional area of the shaft furnace, these axes running off the center of the furnace cross section.
The screw conveyors arranged according to the invention effectively prevent the build-up of bulk pyramids on the inner edge of the shaft furnace. Thus, the reaction material subsides uniformly and the dwelling times of the ores or the reduced ores, respectively, in the shaft furnace are no longer different. Moreover, this arrangement decreases the load of the bearing of the axes and essentially reduces the frequency of repair.
According to the invention, the screw conveyors are arranged in a way that the axes are not aligned to the center of the shaft furnace but point past the center of the shaft furnace as it were, axis meaning both the geometric center line of a screw conveyor, unless otherwise designated, and the mathematical production of this line up to the point of intersection with the inner generated surface of the shaft furnace. The axis of the screw conveyor is thus skew to the center line of the shaft furnace running vertically through the shaft furnace.
~..o.b.., - ~ n..w...P..~,.,.~.n""~.W",.~.,.~., Another advantage of the invention is that the skew screw conveyors exert a torque on the bulk material in the shaft furnace. Accordingly, owing to the discharge achieved by the screw conveyors, the bulk material descends not only by gravity but moves essentially spirally in the area of the skew screw conveyors within the shaft furnace.
This additional spiral movement leads to an intimate mixing of the bulk materials and effectively prevents the formation of takings and channels.
The normal distance of tf~e axis to the center fine of the shaft furnace may be equal or different for all screw conveyors of one plane of screw conveyors. This skew arrangement of screw conveyors reduces the wedge-shaped area between two adjacent screw conveyors above which bulk pyramids may build up.
According to another feature of the invention, the axes of the screw conveyors are inclined upwards or downwards in relation to the horizontal line.
Preferably an angle of up to 70° is included by the axes of the screw conveyors and the horizontal line, an angle of inclination of 30° to 50° being particularly preferred.
On the one hand, this has the advantage that the screw conveyors are less subjected to bending stresses but rather, to tensile or compression stresses, depending on the direction of inclination. Moreover, an additional portion of the bulk pyramids is removed:
According to a preferred embodiment, the screw conveyors of the arrangement according to the invention are an-anged in two superposed level sections, one of these sections, for example, the lower one, showing an actually known radial, horizontal arrangement of screw conveyors. In the second section, the screw conveyors are inclined according to the invention, for example, downwards and aside.
~..~.~,- ~ °......~...,~.n"~".m,~.~.,.n., According to another embodiment, both level sections have an equally large number of screw conveyors, wherein the openings for the screw conveyors into the shaft furnace of both level sections are uniformly distributed over the circumference of the shaft furnace and wherein the openings of the screw conveyors into the shaft furnace of the upper level section are offset against the openings of the lower level section by up to half the central angle between two adjacent openings in circumferential direction.
This arrangement combines the advantages of the radial arrangement as well as of the skew arrangement of screw conveyors. A radial arrangement of screw conveyors is suitable for discharging material from the center of the shaft furnace but involves the known problems regarding the bulk pyramids on the inner edge of the shaft furnace.
A plane of screw conveyors located above or below, however, is suited to remove these bulk pyramids on the inner edge of the shaft furnace or to prevent their formation.
According to another embodiment of the arrangement according to the invention, two or more screw conveyors supported on both sides in the circumference of the shaft furnace are arranged in parallel and in a horizontal plane. However, an arrangement of parallel screw conveyors cannot cover the entire furnace cross section. Therefore, one group each of at least two screw conveyors is preferably provided on both sides of the parallel screw conveyors, the axes of the screw conveyors of each group being aligned in a way that they show a point of intersection off the center of the furnace cross section and the point of intersection of the axes of one group of screw conveyors each being located in the same half of the furnace cross section as the screw conveyors of the group proper.
An arrangement of screw conveyors of such design allows to essentially cover the entire furnace cross section and, thus, to achieve a uniform discharge of the bulk material.
In the following, the an-angement according to the invention is explained in greater detail by the embodiments represented in the drawings, Fig. 1 to Fig. 3.
Fig. 1: Schematic shaft furnace, screw conveyors in two level sections, wherein the screw conveyors of the upper level sections are inclined according to the invention.
Fig. 2: Horizontal section through the shaft furnace, top view of screw conveyors.
~....d..,. ~ d..,...,a...w...a."...~".....,.~, Fig. 3: Alternative embodiment: Combined continuous, parallel screws with one group each of three screw conveyors on both sides of the parallel screws, top view.
Fig. 1 displays the side elevation of a vertical section through shaft furnace 1 containing packed bed 2 of lump material, which is discharged from the shaft furnace by means of schematically represented screw conveyors 3, 4. Screw conveyors 3, 4 are arranged in two level sections 5, 6, with screw conveyors 4 of lower level section 6 showing a known radial arrangement, their axes thus being located in one plane. Screw conveyors 3 of upper level section 5 are inclined upwards according to the invention, angle a of approximately 40° being included by the axes of screw conveyors 3 and the horizontal line.
Fig. 2 displays the top view of a horizontal section through shaft furnace 1, showing the radial an-angement of screw conveyors 4 of lower level section 6. The axes of screw conveyors 3 of upper level section 5 are inclined aside by angle j3 of approximately 20° in relation to those of a radial arrangement. Openings 8 of screw conveyors 3 into shaft furnace 1 of upper level section 5 are offset against openings 7 of screw conveyors 4 into shaft furnace 1 of lower level section 6 by approximately one third of central angle y between two adjacent openings, which is approximately 60°.
Fig. 3 displays the top view of an alternative embodiment, wherein three continuous, parallel screw conveyors 9 each are supported on both sides in cylinder jacket 10 of shaft furnace 1. One group 11, 12 each of short screw conveyors is provided on both sides of screw conveyors 9 arranged in parallel, whose axes show one point of intersection each which is located off the center of the shaft furnace. This arrangement of screw conveyors 9, 11, 12 ensures a uniform discharge of bulk material from shaft furnace 1.
Claims (7)
1. Arrangement for discharging lump material (2), particularly lump material containing iron oxide and/or sponge iron and coming from a shaft furnace (1), particularly from a direct reduction shaft furnace, wherein the shaft furnace (1) is designed as essentially cylindrical hollow body with an essentially circular horizontal cross section and wherein the discharging device is comprised of screw conveyors (3, 4) projecting into the shaft furnace above the bottom of the shaft furnace, characterized in that a number of screw conveyors (3) are aligned along axes whose projection onto the horizontal cross-section area of the shaft furnace (1) or the mathematical productions of the projection of these axes form secants of the horizontal cross-sectional area of the shaft furnace (1), these axes running off the center of the furnace cross section.
2. Arrangement according to claim 1, characterized in that the axis of a screw conveyor (3) is inclined upwards or downwards in relation to the horizontal line.
3. Arrangement according to claim 2, characterized in that the angle included by the axis of a screw conveyor (3) and the horizontal line is up to 70°.
4. Arrangement according to claim 3, characterized in that the angle included by the axis of a screw conveyor (3) with horizontal line is 30° to 50°.
5. Arrangement as claimed in any of claims 1 to 4, characterized in that screw conveyors (3, 4) are arranged in two superposed level sections (5, 6), one of the level sections (6) showing an actually known radial horizontal arrangement of screw conveyors (4).
6. Arrangement according to claim 5, characterized in that both the upper and the lower level sections (5, 6) have an equally large number of screw conveyors (3, 4), that the openings (8, 7) of the screw conveyors (3, 4) into the shaft furnace (1) of both level sections (5, 6) are uniformly distributed along the circumference of the shaft furnace (1) and that the openings (8) of the screw conveyors (3) into the shaft furnace (1) of the upper level section (5) are offset against the openings (7) of the lower level section (6) by up to half the central angle between two adjacent openings in circumferential direction.
7. Arrangement according to claim 1, characterized in that two or more screw conveyors (9) each supported on both sides in the cylinder jacket (10) of the shaft furnace (1) are arranged in parallel and in a horizontal plane and that one group (11, 12) each of at least two screw conveyors each is provided on both sides of the parallel screw conveyors (9), the axes of the screw conveyors of each group (11, 12) being aligned in a way that they show a point of intersection off the center of the furnace cross section, the point of intersection of the axes of one group of screw conveyors (11, 12) each being located in the same half of the furnace cross section as the screw conveyors of the group proper.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0192297A AT405765B (en) | 1997-11-13 | 1997-11-13 | DEVICE FOR DISCHARGING PIECE OF GOODS |
| ATA1922/97 | 1997-11-13 | ||
| PCT/EP1998/006793 WO1999025881A1 (en) | 1997-11-13 | 1998-10-26 | Device for withdrawing lumpy material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2310022A1 true CA2310022A1 (en) | 1999-05-27 |
Family
ID=3523930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002310022A Abandoned CA2310022A1 (en) | 1997-11-13 | 1998-10-26 | Device for withdrawing lumpy material |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP1029087A1 (en) |
| JP (1) | JP2001523760A (en) |
| KR (1) | KR20010032033A (en) |
| CN (1) | CN1278870A (en) |
| AT (1) | AT405765B (en) |
| AU (1) | AU1336299A (en) |
| BR (1) | BR9814191A (en) |
| CA (1) | CA2310022A1 (en) |
| PL (1) | PL340566A1 (en) |
| TW (1) | TW393515B (en) |
| WO (1) | WO1999025881A1 (en) |
| ZA (1) | ZA9810206B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101893371B (en) * | 2010-07-20 | 2011-12-07 | 中冶赛迪工程技术股份有限公司 | Material flow device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3067097D1 (en) * | 1979-05-09 | 1984-04-26 | Foster Wheeler Power Prod | Vertical pyrolysing furnace, more particularly for tyre pieces |
| AT372109B (en) * | 1982-01-11 | 1983-09-12 | Voest Alpine Ag | DEVICE FOR DISCHARGING HOT GOODS, ESPECIALLY IRON SPONGE FROM A CHAMBER |
-
1997
- 1997-11-13 AT AT0192297A patent/AT405765B/en not_active IP Right Cessation
-
1998
- 1998-10-26 AU AU13362/99A patent/AU1336299A/en not_active Abandoned
- 1998-10-26 JP JP2000521243A patent/JP2001523760A/en not_active Withdrawn
- 1998-10-26 KR KR1020007005152A patent/KR20010032033A/en not_active Application Discontinuation
- 1998-10-26 WO PCT/EP1998/006793 patent/WO1999025881A1/en not_active Application Discontinuation
- 1998-10-26 CN CN98811081A patent/CN1278870A/en active Pending
- 1998-10-26 PL PL98340566A patent/PL340566A1/en unknown
- 1998-10-26 EP EP98956875A patent/EP1029087A1/en not_active Ceased
- 1998-10-26 CA CA002310022A patent/CA2310022A1/en not_active Abandoned
- 1998-10-26 BR BR9814191-0A patent/BR9814191A/en not_active Application Discontinuation
- 1998-11-02 TW TW087118225A patent/TW393515B/en not_active IP Right Cessation
- 1998-11-09 ZA ZA9810206A patent/ZA9810206B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| CN1278870A (en) | 2001-01-03 |
| BR9814191A (en) | 2000-09-26 |
| ATA192297A (en) | 1999-03-15 |
| JP2001523760A (en) | 2001-11-27 |
| AT405765B (en) | 1999-11-25 |
| WO1999025881A1 (en) | 1999-05-27 |
| KR20010032033A (en) | 2001-04-16 |
| AU1336299A (en) | 1999-06-07 |
| TW393515B (en) | 2000-06-11 |
| ZA9810206B (en) | 1999-05-17 |
| PL340566A1 (en) | 2001-02-12 |
| EP1029087A1 (en) | 2000-08-23 |
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Legal Events
| Date | Code | Title | Description |
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| FZDE | Dead |