EP1017859B1 - Process for producing sponge iron - Google Patents

Abstract

A device for producing sponge iron from iron oxide lumps consists of a reduction shaft in which a hot dust laden reducing gas is delivered. The gas is produced in a gas generator by means of partial oxidation of solid carbon carriers and passes into the lower end of the reduction zone via lateral reduction gas inlets. The iron oxide lumps are fed to the upper area of the reduction shaft and are radially fed as sponge iron to the lower end of said reduction shaft via delivery organs. The delivery organs are arranged in such a manner that the sponge iron is conveyed only radially outwardly.

Description

The invention relates to a method according to the preamble of claim 1.

When reducing lumpy iron oxides in one The iron sponge generated in the reduction shaft lower part of the reduction shaft discharged from this. One described in EP 0 085 290 A1 The possibility of this discharge is that the Sponge iron by means of radially acting discharge elements, especially screw conveyors, from the side of the reduction shaft furnace is dissipated. By the radial Arrangement of the screw conveyor exist between these lateral spaces (dead areas), which are extend towards the inner wall of the reduction shaft. Immobile are built on these spaces Zones of the miller moving down through the shaft, so-called "dead men". Furthermore it is problematic, the discharge organs for reasons of strength in terms of their diameter and length to make any size, so that usually also in the middle of the reduction shaft between the inner ones Ends of the discharge elements (snail heads) one there is a dead surface on which there is also a "dead Man "(central" dead man "). The height these "dead men" depends on the size of the respective space and the angle of repose the dump of rubble. Especially with higher dust levels due to the dust content of the reducing gas this angle of repose is very steep and the inner one Very high friction. The can over the interspace surfaces of the screw conveyors "dead men" and the central "dead man" each other support. The "dead men" have one potentially harmful influence on uniformity the gassing of the Moller and the Moller movement in the shaft and thus on the evenness the reduction of iron oxides.

EP 0 166 679 A1 discloses an arrangement of one Smelting gasifier and a direct reduction shaft furnace with a bed of lumpy iron oxide, where the shaft furnace has a floor to support the pouring column, discharge openings in the floor for Discharge of the iron sponge particles and at least one Inlet for the reducing gas supplied by the carburetor in the lower section of the pouring column. Since the reducing gas is very dust-laden, there is a risk of blockage of the free spaces in the column with the consequence of a corresponding increase in volume resistance for the reducing gas. To enable that too a gas loaded with a larger proportion of dust fed directly to the carburetor of the reduction shaft furnace can be without clogging the Gaps in the column and as a result to an uneven gas distribution in the shaft furnace and thus malfunctions are radially arranged Screw conveyors are intended for permanent mutual reciprocating movement of the particles the bed in the inlet for the reducing gas adjacent, through which the reducing gas flows Area, and continues to be at the opposite At least ends of the screw conveyors in the ground a discharge opening for the sponge iron particles is arranged. The screw conveyors can be driven in this way done that either the individual snails in succession rotated in both directions or a combination of constantly outward and snails continuously conveying inside is.

Both discharge openings are opposite in this arrangement shielded the pouring column; the outer through a ring apron and the inner one by a cone. The cone ends just above the screw conveyor or it contains passage openings into which the inner ones Grip the ends of the radially arranged screws. This ensures that the sponge iron not directly, i.e. without additional funding bodies reaches the discharge openings, but only transported to these by means of the screw conveyors can be. This is necessary to the back and forth to produce the resulting movement of the sponge iron.

Since the bulk of the rubble is also on the middle Supporting the discharge opening shielding cone is also here the appearance of "dead men" probably.

Starting from EP 0 166 679 A1, it is therefore the Object of the present invention, a method for the production of sponge iron from lumpy iron oxides using in a reduction shaft of a hot dusty reducing gas, which is in a gas generator by partial oxidation of solid Carbon carriers generated and over side Reduction gas inlets at the lower end of the reduction zone is introduced into the reduction shaft at of the lumpy iron oxides in the upper part of the Reduction shaft entered and as sponge iron radial at its lower end by discharge members be carried out, and in the middle range of the reduction shaft below that between the inner ends of the discharge organs formed surface in An additional discharge opening at the bottom of the reduction shaft is intended for the sponge iron, too create in which building a "dead man" at least above which is in the middle between the radial Discharge organs located area avoided becomes.

According to the invention, this object is achieved by a Method with the features specified in claim 1. Advantageous further developments of the invention Procedures result from the subclaims.

The fact that the discharge organs only the sponge iron Convey radially outwards, finds no reciprocating Movement of the sponge iron on the bottom of the Reduction shaft instead and the middle discharge opening need not be shielded, so that no more "dead men" in the middle and in the essentially also laterally between the discharge elements can train. Since that too over the side Surface furniture material is no longer on central "dead man", it will be with the Sink in the reduction shaft to a significant Part directed to the additional discharge opening.

The iron sponge sinking downwards is advantageous by one arranged between two discharge elements and rising above this Guide device to the side of the discharge elements and directed radially to the additional discharge opening. This increases the steering of the furniture material to the discharge organs and the additional Discharge opening reached.

Preferably, a guide device with a Edge of the additional discharge opening diagonally upwards extending to the inner wall of the reduction shaft used upper edge, with the guide device downwards and radially outwards to Width of the lateral space can expand between the discharge organs. This ensures that the entire furniture material evenly sinks down until it's discharged becomes.

By dividing the deduction into an outer and center area the rate of descent in the range of the shaft outside diameter and in the area Controlled independently of each other via the center discharge become. Thus - in connection with the individual adjustable discharge speeds of the Discharge devices - targeted control of the shaft aisle possible across the entire shaft cross-section.

A reduction shaft with one is advantageous located below the additional discharge opening Manhole with the same or down tapering or expanding diameter whose lower end is closed and in which above of the bottom at least one other radially acting Discharge device for the sponge iron is arranged, used.

Fig. 1

den unteren Teil eines Reduktionsschachtes in senkrechter Schnittdarstellung gemäß einem ersten Ausführungsbeispiel,

Fig. 2

einen horizontalen Schnitt durch den Reduktionsschachtofen in der Ebene II-II in Fig. 1, und

Fig. 3

den unteren Teil eines Reduktionsschachtes in senkrechter Schnittdarstellung gemäß einem zweiten Ausführungsbeispiel.

The invention is explained in more detail below with reference to exemplary embodiments shown in the figures. Show it:

Fig. 1

the lower part of a reduction shaft in a vertical sectional view according to a first embodiment,

Fig. 2

a horizontal section through the reduction shaft furnace in the plane II-II in Fig. 1, and

Fig. 3

the lower part of a reduction shaft in a vertical sectional view according to a second embodiment.

The figures show the part of the reduction shaft below the bustle level, i.e. the level in which the reducing gas is blown into the shaft to climb up through the Möller and the conversion of iron oxides into sponge iron cause.

The reduction shaft has a cylindrical or in areas conical jacket 1 on the bottom Ends in the ground 2. Immediately above of the bottom 2 there are several, for example ten side discharge openings for the iron sponge containing Möller, which in uniform Distance in the circumferential direction along the jacket 1 in are distributed on a horizontal plane. Through each this discharge opening is a discharge organ in the form a screw conveyor 3 out. The screw conveyors 3 transport the sunken to the floor 2 Möller radially outwards so that it is in each case Downpipe 4 passes through which it, for example into a melter gasifier generating the reducing gas to be led. This discharge of Möller enables the sinking of the furniture in the reduction shaft.

The radial screw conveyors 3 only extend over part of the radius of the reduction shaft, so that the snail heads a distance from the Have shaft axis and a circular area between form. The bottom 2 contains one of these circular areas corresponding middle discharge opening, which in a cylindrical shaft 5 with respect to that of Reduction shaft corresponding to a reduced diameter transforms.

Above the bottom 2 is between each two screw conveyors 3 a wedge-shaped guide element 6. The front or upper edge of the guide elements extends from the edge of the middle discharge opening rising up to the inner wall of the jacket 1, the slope angle of this edge compared to the Vertical is about 25 to 40 °. Continue to expand the guide elements 6 starting from this edge downward and radially outward so that their surface of the dead lying on the ground Area between two screw conveyors 3 corresponds. The angle of inclination of the side surfaces of the guide elements 6 is approximately in the range of 5 to 15 °.

The guide elements 6 guide the sinking Möller so to the middle discharge opening in the bottom 2 as well to the screw conveyors 3 that practically the whole Möller is carried out unhindered, that means that The occurrence of "dead men" is prevented.

The part of the Möllers reaches in the embodiment according to FIGS. 1 and 2 in the shaft 5 closed at the bottom To remove the material from this are immediate above the bottom of the shaft 5 two each other diametrically opposite discharge openings are provided, through which each also a screw conveyor 7 is passed through for discharge to a downpipe 8, which, for example, in the melter leads. Because the diameter of the shaft 5 is significant is smaller than that of the reduction shaft the screw conveyors 7 each over the middle of the Shaft 5 out, so that everyone in the shaft 5 entering Möller without stowage to the downpipes 8 is transported.

Instead of the screw conveyor 8, others can Discharge elements provided at the bottom of the shaft 5 be, for example, a rotary valve or a Bunkerräumer.

3 closes a shaft at the middle discharge opening in floor 2 9, whose inner diameter is steadily downwards decreases and at the lower end about 1 m or less is. The lower end of the shaft 9 is open, so that the Möller can emerge from it. He falls on a walking beam 10, which is in a chamber 11 is located with an outlet pipe 12. The walking beam 10 leads depending on the amount of from the Shaft 9 exited Möllers swivel movements through and causes a discontinuous release of this to the outlet pipe 12.

The outlet pipe 12 is centrally through a coal liner 13 in the head of a melter gasifier 14 guided. The coal liner 13 comprises a vertical one Feed pipe from a coal bunker and a two-stage Screw conveyor. Because of the concentric Introduction of furniture material or sponge iron and Coal in the head of the melter 14 is the Mixing promoted by this, so that Melting the sponge iron and generating the Reducing gas in the melter 14 improved become.

Claims (13)

1. Process for producing sponge iron from iron oxide lumps in a reduction shaft, using a hot dust laden reduction gas which is produced in a gas generator (14) by partial oxidation of solid carbon carriers and introduced via lateral reduction gas inlets at the lower end of the reduction zone into the reduction shaft, and where the iron oxide lumps are fed into the upper area of the reduction shaft and radially delivered at its lower end by delivery organs (3) as sponge iron, and in which an additional delivery opening for sponge iron is provided in the central area of the reduction shaft below the surface formed between the inner ends of the delivery organs (3) in the base of the reduction shaft, characterised in that the delivery organs (3) convey sponge iron only radially outward.
2. Process according to Claim 1, characterised in that the downward sinking sponge iron is diverted laterally to the delivery organs (3) and radially to the additional delivery opening by a guiding device (6) arranged between two respective delivery organs (3) and upwardly protruding over the latter.
3. Process according to Claim 1 or 2, characterised in that screw conveyers (3) are used as delivery organs.
4. Process according to one of Claims 1 to 3, characterised in that a guiding device (6) is used the upper edge of which extends from the edge of the additional delivery opening at a slant upward to the inside wall of the reduction shaft.
5. Process according to Claim 4, characterised in that a guiding device (6) with an inclination angle of the upper edge of between approximately 25 and 40° relative to the vertical is used.
6. Process according to one of Claims 1 to 5, characterised in that a guiding device (6) is used which extends downward and radially outward up to the width of the lateral intermediate space between the delivery organs (3).
7. Process according to Claim 6, characterised in that a guiding device (6) is used which as an inclination angle of its lateral surfaces of between approximately 5 and 30° relative to the vertical.
8. Process according to one of Claims 1 to 7, characterised in that a reduction shaft is used which has a shaft (5) located below the additional delivery opening with downwardly narrowing, unchanging or increasing diameter, the lower end of which is sealed and wherein above the base is arranged at least one further radially operational delivery organ (7) for sponge iron.
9. Process according to Claim 8, characterised in that a screw conveyer (7) is used as an additional delivery organ.
10. Process according to Claim 8, characterised in that a rotary-vane feeder is used as additional delivery organ.
11. Process according to Claim 8, characterised in that a bunker clearing device is used as additional delivery organ.
12. Process according to one of Claims 1 to 7, characterised in that a reduction shaft is used which has a vertical shaft (9) located below the additional delivery opening and with downwardly decreasing diameter, which has at the lower end a delivery opening for sponge iron and terminates in a chamber (11) with delivery pipe (12) in which a lifting beam (10) is provided below the delivery opening at the lower end of the shaft (9).
13. Process according to Claim 12, characterised in that a delivery pipe (12) is used which is ducted through the delivery pipe (13) for delivery of solid carbon carriers into the gas generator (14).

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