EP0760395B1 - Installation for the liquid metal transportation in the casthouse of a shaft furnace and process for handling this installation - Google Patents

Abstract

Equipment for molten metal handling in the casting area of a blast furnace, comprising at least one main channel (2) with syphon (11) installed at a tap hole (1<.>2), together with run-out channels (12) and a transfer station for molten metal ladles or cars. A flanged pipe (3) between the tap hole (1<.>2) and the main channel (2) has connections (3<.>1, 3<.>2) for a drilling machine (4) and a hole stopping machine (5), and an inert gas feed (7) and a slide gate (6) with ceramic plate is arranged between the flanged pipe (3) and the inlet (2<.>1) of the main channel (2). The main channel (2) with syphon (11) is sealed gastight by a cover (9) with flap (8). The outlet (2<.>2) of the main channel (2) has a slide gate with ceramic plate and at least one metal run-out pipe (12) terminating in a T-branch (13) and pipe bends (14), with slide gates (6) with ceramic plates between T-branch (13) and pipe bends (14). A method of operating the equipment is also claimed.

Description

The invention relates to a device for liquid metal transport in the casting hall of a shaft furnace, especially blast furnace, and a method for Operation of this device consisting of at least one installed after tapping the blast furnace Main channel with siphon and downstream drainage channels with a transfer station in the liquid metal transport containers or trolley exists.

The casting hall technology on blast furnaces has not changed fundamentally in recent decades. The tap hole is still drilled for each tap of the liquid metal and then plugged again. Improved tamping compounds have been developed and the tamping performance (l / sec, kg / cm ² ) as well as the drilling performance (drilling depth, torque, impact drilling) have been improved, but the timely opening and closing of a blast furnace tapping still depends to a certain extent on coincidences . When opening, the introduction of bar kickback technology, in which a steel bar is inserted into a freshly stuffed tap hole, which is knocked out backwards for the next tap, has brought certain improvements, but the problem is still not solved satisfactorily.

The separation of the liquid metal in pig iron and Slag due to their different specific Weights still take place in the so-called Main channel instead. Main channels have been around for some Years as so-called pool channels with relatively large Dimensions in which there is always a liquid residue Pig iron remains, executed. Are typical at Large blast furnace channels of 12 - 15 m length and 2.0 to 2.5 m width. Such large and heavy channels with weighing up to 250 t after new delivery difficult to change and require handling heaviest cranes, which in turn are on one heavy hall construction run. That's why you have decided in many places, but not the main channel changeable, but stationary. The disadvantage here is that after each generation of 0.6 up to 0.8 million tons of pig iron requiring several days Refractory repair is needed, which is under unfavorable Conditions within the casting hall got to. During this time, the racking in question can not be used.

Progress brought here from the EP 0 279 165 B1 known quick change trough. This Gutter is less than a change option 8 h designed so that the change within one normal repair shift can be made. To the No heavy crane is required to change; the worn channel is hydraulic with the help Lifting devices lowered onto a special vehicle, a newly delivered trough will use the same lifting equipment picked up by a second vehicle. The cooling, breaking out and repositioning of the gutter takes place under workshop conditions outside the Blast furnace area.

The liquid metal initially flows in the main channel through a siphon (fox) to separate pig iron and slag; after that the slag-free flows Pig iron through open, but mostly like the main channel also covered with plates or hoods, with ff material supplied channels to the different Parking spaces for pig iron transport vehicles. For targeted control of these parking spaces either dust sheets protected with ff material pulled one after the other, or so-called tipping channels come with electric or hydraulic drive for Commitment.

The slag separated at the siphon or fox in turn leaves the main channel and comes via open or with Covered gutters either to a slag pan, a pelletizer with water or freezes through natural cooling in one Cinder bed made of sand.

The care and keeping the pig iron and Slag chutes are the main cause of this heavy manual work, even in casting shops still occurs when machines - wherever possible - be used.

Red dust (Fe oxide) accumulates particularly at the tap hole, the tipping channel and at the pig iron inlet in the transport vessel, but to a lesser extent also at the pig iron and slag channels covered with hoods and the main channel. This forms as a result of the hot pig iron coming into contact with the surrounding air. In order to remove the red dust, dedusting systems for high suction volumes are installed using the technology that is common today. These dedusting systems initially consist of a system for collecting the dusts (hoods, pipes), with several switchable strands being provided on blast furnaces with several tap holes. This in turn requires fittings with large diameters, corresponding actuators and control logic. Depending on the number of taps and the size of the casting hall, the extracted air amounts are in the order of a few 100,000 Nm ³ / h to well over 1.0 million Nm ³ / h. With intensive suction, the contact of the hot pig iron with air is naturally intensified and the amount of dust per ton of pig iron increases.

To separate the dusts are large Fabric and electrostatic filters installed. In front or behind a fan station must be provided for the filters, their drive power depending on the suction volume and System pressure loss easily in the order of magnitude some MW can come. The cleaned gas is over released a fireplace into the atmosphere.

The disposal of the often Zn- and Pb-containing dusts requires additional equipment (e.g. pelletizing plate, Intermediate bunker) and will with increasing environmental requirements more problematic.

Overall, the dedusting devices described above require a considerable effort Investment and operating costs. It's not like that It is surprising that numerous proposals for Prevention / suppression of dust formation in the Literature are described and partly also in the Practice have found entrance.

Devices for partitioning / housing are known of the pig iron flow through mechanical devices such as Hoods, covers and the like.

DE 39 03 444 C1 describes one method and one Device for preventing air contact from Pig iron by fogging with inert gas, e.g. B. Nitrogen known from the tap hole of the metallurgical furnace leading the liquid metal Drainage channels to form the smallest possible free flow of liquid metal Interior are covered, the transfer point, in of the liquid metal from the transport and Drainage channel is passed into a pouring vessel, is shielded largely gastight, with both the free interior of the covered gutters as well the largely gas-tight shielded interior of the Transfer point and the pouring vessel interior with Be flushed with inert gas. The liquid metal discharge jet is from the outlet opening into the pouring vessel from a ring-shaped one that prevents air from entering Inert gas jacket additionally shielded.

The device consists of at least one on one Tap opening of the metallurgical furnace installed Transport and drainage channel, a transfer station with a swivel or tilting channel and a distribution system for the liquid metal in a pouring vessel, each Transport and drainage channels over their entire length or has several covers, one as possible small free, d. H. not flowed through by the liquid metal Form interior.

The transfer stations including the outlet openings are largely gastight due to a closed Shielded housing.

In the covers and in the transfer station housing nozzles are provided for the supply of inert gas.

A disadvantage of this tapping system is that of high temperature of the pig iron triggered thermals that a constant replenishment of the inert gas required.

The present invention therefore has the task posed, a timely, safe and fast Opening and closing of blast furnace tap holes ensure suppression of dust formation in the areas taphole, main channel, pig iron and Slag chutes to allow a reduction in manual work in the gutter area a reduction in investment and operating costs to contribute.

These tasks are solved in the same way as it is is specified in claims 1 and 9. Advantageous further developments are in the Subclaims called.

According to the invention, between the racking on the blast furnace and the main channel is lined with ff material Pipe section arranged. On both sides of the pipe section are a stationary drill and one stationary tamping machine arranged. This is the Pipe section itself with two connecting pieces equipped, through which the drill of the drill or the trunk of the tamping machine is guided.

On the side of the pipe section facing the main channel becomes a ceramic (first) slide closure installed as it is from steelworks technology Closure for steel ladles is known. Immediately in front of and behind the slide lock Inert gas connections with control valves arranged.

The process of opening and closing the tap hole is carried out as follows:

Normally the ceramic (first) slide lock is used for tapping opened and then closed again. Immediately after the closing is over the Inert gas connection, the tap hole was washed free of pig iron and this state by automatically setting one maintain a small inert gas flow rate. The pig iron solidifies in the tap hole and a blocking of the slide closure avoided.

From time to time it is necessary to do either through the tap hole washed out by the hot metal stream Repair plug, or the ceramic one Change the plate of the slide lock.

In these repair cases, at the end of the racking the ceramic slide lock closed and that Tap hole with inert gas over the connection of pig iron washed away. Then the stationary drilling machine operated; this first drills one Connection piece free of hardened stuffing, with which is flanged to the pipe section itself. The The drill then crosses the tap hole and drills one Channel in the hardened stuffing, the other Fills the connecting piece with which the stationary Tamping machine is flanged to the pipe section. The Drill is then pulled back to its original position, and the tamping machine is operated. The stuffing fills the tap hole towards the blast furnace; at the same time penetrates stuffing material in the direction of the stationary drilling machine to the tip of the drill bit, and at the same time it moves the stuffing also on the slide closure without however, to fully reach the ceramic slide plate, because an inert gas cushion forms in front of it.

The subsequent opening of the tap hole is followed by Opening a flap veiled with inert gas at the top of the cover of the main channel second, above the main channel in an inclined position - Inclination approx. 6 ° according to the inclination of the tap hole - arranged drill after opening the ceramic slide closure operated.

This drill drills the tap hole through the Pipe section as well as through the inside of the On the FF lining. As soon as the tap hole is free, the drill will be withdrawn and the flap closed. To the unavoidable occurring during this drilling process To collect dust is on the exhaust hood a dedusting line connected to a small, only for the duration of the drilling process operated filter system, leads.

As already explained, the main channel is one Covering hood covered. The connection between The main channel and cover hood are known per se Way carried out so that the entry of outside air the pig iron bath located inside the main channel is largely suppressed, e.g. B. by means of a sand cup. The cover hood can be raised and lowered mechanically as well as laterally movable, for inspections and possibly ff repairs quick access to To create the main channel.

At the end of the main channel there is a siphon (fox) the liquid metal in pig iron and slag due to separates their different densities. While the slag in a conventional manner Leaving the main channel via open or covered Gutters to a pelletizer, to one Slag pan, to a slag pit or Slag bed arrives, the transport of the liquid pig iron to the parking spaces of the Pig iron transport vehicles no longer, as before usual, in gutters. Instead, use ff material multilayer lined metal pipes used by an insulating layer arranged on the outside inwards Have permanent lining and a wear lining. This Metal pipes are divided into lengths of 1 - 2 m, thus the relatively light weight with a handling makes light lifting equipment possible. Between wear and permanent lining, a wire mesh is placed; each tube length also has one metallic pin that the entire ff-delivery of penetrates inside and out in contact with the liquid pig iron is available when this through the Pipe length flows. By a suitable electrical Circuit it is possible to instantly recognize if at one point the molten pig iron Wear lining has consumed so far that this in Comes into contact with the wire mesh. The person in question Pipe length can be reduced at the next opportunity Effort changed and a freshly delivered one Pipe section can be used.

The pipe system comes with appropriate branches provided so that it has all the designated parking spaces with Can supply pig iron. Switching the pig iron flow from one parking space to the other takes place by means of remote operated ceramic slide closures.

Such heating has the advantage that, on the one hand the pig iron does not solidify and on the other hand none Temperature change stress for the Refractory lining occurs.

In addition, at the beginning of the pipe system is behind the Main channel another ceramic (second) slide lock intended. With this the pipe system can Main channel to be shut off. Hereby it will possible to close the piping system through a burner heat, ensuring that they are called Burner gases the pipe system along its entire length heat; they escape at the elbows on Parking space of the pig iron transport vehicles and not towards the main channel.

The flow of molten cast iron in one completely encapsulated and filled piping system prevents the entry of air and thus the emergence of dust on this part of the transport route.

To suppress dust at the parking spaces, the Pipe elbow pulled down as far as possible (Restriction: clearance profile). To also with the inevitable, remaining piece of free fall of the To prevent the formation of dust is here in a manner known per se with a Inert gas curtain worked.

By delivering the pipes with high-quality ff materials the durability increases. On It is rarely necessary to replace the pipes. It is only made when the wear is on has reached the specified level. The pipes breaking out takes place after they have cooled down under workshop conditions outside the casting hall.

The main channel is designed as a quick change channel. No heavy lifting gear is needed to change them needed, but lowering the used and the new main channel is lifted with a hydraulic lifting device, such as from known from EP 0 279 165 B1.

The cooling, breaking out and repositioning of the heavy Change channel takes place under workshop conditions outside the casting hall. Due to the measures described above, the scope the heat work is reduced and the working conditions designed more efficiently.

The above-described configuration of the Last but not least, blast furnace casting hall technology leads to one very substantial reduction in investment costs; the heavy casting hall crane that was previously necessary is no longer required, it is only a light hoist with a small span required. The required hall space and that Steel construction weights are reduced considerably. The elaborate hoods and piping systems for Detection of dust inside the casting hall are eliminated as well as the large filter system Blower station, chimney and dust silo. The operating costs are due to reduced operating expenses the filter station - maintenance, electricity costs for Blower - and the elimination of the costs for removal and Dust disposal significantly reduced.

The invention is based on schematic Embodiments described in more detail.

Fig. 1

eine Draufsicht auf das Abstichsystem,

Fig. 2

einen Längsschnitt im Bereich der Hauptrinne,

Fig. 3

einen Querschnitt durch einen mit ff-Material zugestellten Rohrabschnitt,

Fig. 4

einen Querschnitt mit Anordnung der Abdichtung zwischen zwei Rohrabschnitten.

Show it:

Fig. 1

a top view of the tapping system,

Fig. 2

a longitudinal section in the area of the main channel,

Fig. 3

3 shows a cross section through a pipe section which is supplied with ff material,

Fig. 4

a cross section with arrangement of the seal between two pipe sections.

1 shows a plan view of the tapping system or on one of the liquid metal transport systems of a blast furnace (1) with arranged in the blast furnace shell (1.1) Racking (1.2) with tap hole (1.3).

At the rack (1.2) is a pipe section (3) with a first connection piece (3.1) for a stationary one Drill (4) and a second connection piece (3.2) for flanged a stationary tamping machine (5). To the Pipe section (3) then closes a first slide (6.1) with a ceramic plate and the inlet opening (2.1) of the main channel (2).

After the main channel (2) with siphon (Fuchs) (11), to Separation of pig iron and slag, are at the Outlet opening (2.2) a number of pipe sections (12), which are lined with ff material, gas or hermetically connected in a T-shaped Pipe section (13) open. On both outflow sides of the T-shaped pipe section (13) are between the down pipe elbows (14) with a Inert gas curtain (17) one (third) slide valve (6.3a) and (6.3b) arranged to add the molten pig iron to manage one of the parking spaces (16a, 16b), where it can flow off in the pig iron transport wagon (18).

At the pipe section (3) before (in the sense of Pig iron flow) and behind the first slide (6.1) on the Inlet opening (2.1) of the main channel (2) Inert gas feeds (7) arranged. Another Inert gas supply (7) is at the outlet opening (2.2) the main channel (2). A burner (15) for Heating the pipe sections (12) is in the first Pipe section arranged after the main trough (2).

Fig. 2 shows a longitudinal section through the front part the liquid transport system. At the racking (1.2) gas-tight a pipe section (3) with connecting piece (3.1, 3.2) flanged to which a second Connects pipe section (3) with a first slide (6.1). This second pipe section (3) is with the inlet opening (2.1) the main channel (2) also gas-tight connected. At the outlet opening (2.2) of the main channel (2) is another pipe section (12) with a second one Flanged slide (6.2) to the other if necessary Pipe sections (12) are added. At the end of Pipe sections (12) becomes a T-shaped pipe section (13) arranged the pig iron in one of two Cast iron dolly is flowing.

The main channel (2) is designed as a quick change channel. It becomes worn after the ff lining about tension elements, not shown, on tie rods slide down and up from the operating position in Height of the racking platform on a standing in the hallway Transport vehicle lowered. The tie rods are on Main beam support brackets (2) attached.

Fig. 3 shows the cross section through a ff material pipe section (3/12). The ff material consists of the insulating layer (12.1), the Permanent lining (12.2) and the wear lining (12.3) together.

At the transition from permanent lining (12.2) to wearing lining (12.3) a wire mesh (12.4) is inserted, which over a metallic pin (12.5) with an electrical one Monitoring device is connected to the state of the wear chuck (12.3).

Fig. 4 shows devices for sealing two Pipe sections (3) or (12).

Around the flanges of the two pipe sections (3) or (12) a pipe clamp (3.3) is placed on each side with a supply line (3.4) with shut-off valve (3.5) is provided to a sealant (3.7) in the remaining free gap between the bricked Press pipe sections (3) or (12) into it.

In the free cross section of the wear lining (12.3) is before joining the pipe sections (3) or (12) a plastic plug (3.6) is inserted to prevent the sealant (3.7) from free Cross section of the wear chuck (12.3) blocked or constricts.

List of reference numbers:

1

Blast furnace

1.1

Blast furnace tanks

1.2

Racking

1.3

Taphole

2nd

Main channel

2.1

Inlet opening

2.2

Outlet opening

3rd

Pipe section

3.1

Connection piece for 4

3.2

Connection piece for 5

3.3

Pipe clamp

3.4

Supply line

3.5

stopcock

3.6

Plastic plug

3.7

caulk

4th

Stationary drilling machine

5

Stationary tamping machine

6

Slider locks (6.1; 6.2; 6.3a; 6.3b)

7

Inert gas supply

8th

flap

9

Cover hood from 2

10th

Tap hole drilling machine

11

Siphon (fox)

11.1

Slag channel

12th

Pipe section

12.1

Insulating layer

12.2

Permanent feed

12.3

Wear lining

12.4

Wire mesh

12.5

metallic pin of an electrical Measuring device

13

T-shaped pipe section

14

Pipe elbow

15

burner

16

Parking space for pig iron trolleys

17th

Inert gas curtain

18th

Cast iron dolly

Claims (10)

1. Device for transport of liquid metal in the foundry of a shaft furnace, especially a blast furnace, which consists of at least one main channel, which is installed at a tap hole, with a siphon, outflow channels as well as a transfer station into the liquid metal transport vessels or transport stations, characterised in that

   a) a flanged pipe section (3) with a first connecting stub pipe (3.1) for a drilling machine (4) and a second connecting stub pipe (3.2) for a tap hole plugging machine (5) is provided between the tap (1.2) at the blast furnace (1) and the main channel (2) and that an inert gas feed (7) and a first closure slide (6.1) with a ceramic plate are arranged between the flanged pipe section (3) and the inlet opening (2.1) of the main channel (2),

   b) the main channel (2) together with siphon (11) is gastightly sealed by a cover hood (9) with a flap (8),

   c) a second closure slide (6.2) with a ceramic plate is arranged between the outlet opening (2.2) of the main channel (2) at one other pipe section (12),

   d) at least one other pipe section (12) opens into a T-shaped pipe section (13), and

   e) a respective third closure slide (6.3a, 6.3b) is arranged between the T-shaped pipe section (13) and pipe elbows (14) connected thereto.
2. Device according to claim 1, characterised in that inert gas feeds (7) are provided at the inlet opening (2.1), the outlet opening (2.2) and the flap (8).
3. Device according to claim 1, characterised in that an inert gas veiling means (17) is provided at the pipe elbows (14).
4. Device according to claim 1, characterised in that a stationary drilling machine (4) is provided at the first connecting stub pipe (3.1), a stationary plugging machine (5) is provided at the second connecting stub pipe (3.2) and a stationary tap hole drilling machine (10) is provided above the cover hood (9), at the flap (8).
5. Device according to claim 1, characterised in that a pipe clamp (3.3) with laterally arranged feed ducts (3.4) and blocking valves (3.5) is provided for the sealing of pipe sections from a pipe section with closure slide (6.1; 6.2; 6.3a; 6.3b) as well as of pipe sections amongst one another, of the T-shaped pipe section (13) with a pipe section (12) or with a pipe elbow (14).
6. Device according to claim 1, characterised in that a wire mesh (12.4) and a metallic pin (12.5) of an electrical measuring device are provided in the pipe sections (3, 12, 13) and pipe elbows (14) at the transition of outer linings (12.2) to the closing lining (12.3).
7. Device according to claim 1, characterised in that a burner (15) is arranged at one of the pipe sections (12).
8. Device according to claim 1, characterised in that the main channel is equipped as a quick-change channel.
9. Method of operating a device for transport of liquid metal in the foundry of a shaft furnace, especially a blast furnace, according to claims 1 to 8 and for achieving accurately timed opening and closing of the tap for precise metering of the liquid metal quantity - wherein the device consists of at least one main channel, which is installed at a tap hole, with a siphon and outflow channels with a transfer station into the liquid metal transport vessels or transport carriages - in such a way that

   a) for opening the plugged tap hole (1.3) a tap hole drilling machine (10) drills out the hardened plugging material within the tap hole (1.3) of the tap (1.2) and of a pipe section (3), which is arranged between tap (1.2) and the main channel (2), after opening of the ceramic plate of the first closure slide (6.1) and after opening of a closure flap (8) at the upper side of the closure hood (9) of the main channel (2),

   b) after opening of the tap hole (1.3) a liquid metal flow flows through the one pipe section (3), the opened first closure slide (6.1) and the inlet opening (2.1) in the gastightly screened main channel (2) with the siphon (11), and after separation of the dross the raw iron flow flows through the outlet opening (2.2) through at least one other pipe section (12) by way of an opened second closure slide (6.2) into a T-shaped pipe section (13) and from there passes by way of one of opened third closure slides (6.3a; 6.3b) through a pipe elbow (14) into a raw iron transport carriage (18),

   c) directly after closing of the first closure slide (6.1) mounted in the one pipe section (3) the tap hole (1.3) is rinsed of liquid metal by means of an inert gas and this state is maintained by the setting of a specific inert gas throughflow quantity,

   d) for plugging in the sense of a repair of the tap hole (1.3) rinsed of liquid metal flow or for exchange of the ceramic plate of the first closure slide (6.1) the tap hole of the tap (1.2) is washed by means of an inert gas, a first connecting stub pipe (3.1) of the one pipe section (3) is drilled free of plugging material by a drill of a stationary drilling machine (4) provided in this connecting stub pipe (3.1) of the pipe section (3), and the drill of the drilling machine (4) drills a channel into the hardened plugging material of the tap hole (1.3) and thereafter drills free a second connecting stub pipe (3.2) of the one pipe section of the plugging machine (5), and

   e) for the introduction of plugging material, plugging materials are moved within the one pipe section (3) in the direction of the tap hole (1.3), direction of the first connecting stub pipe (3.1) and direction of the ceramic plate of the first closure slide (6.1) by the plugging machine (5) by way of the second connecting stub pipe (3.2), wherein, however, the ceramic plate of the first closure slide (6.1) is protected by an inert gas cushion against a further penetration of the plugging material or, for the exchange, is kept free.
10. Method according to claim 9, characterised in that for avoidance of pig iron gap runners after repair operations a sealed connection of pipe sections (3, 12, 13) and pipe elbows (14) is effected by introduction of a synthetic material plug (3.6) and a sealing mass (3.7).

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