EP0760395A1 - 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, in particular a blast furnace, and a method for operating this device, which consists of at least one main trough with a fox installed after a tap hole in the blast furnace and downstream drainage channels with a transfer station into the liquid metal transport vessels 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 precise 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 into pig iron and slag due to their different specific weights still takes place in the so-called main channel. Main channels have been designed as so-called pool channels with relatively large dimensions, in which a liquid remnant of pig iron always remains. Typical for large blast furnaces are channels of 12 - 15 m in length and 2.0 to 2.5 m in width. Such large and heavy channels with a weight of up to 250 t are new difficult to change and require the heaviest cranes to operate, which in turn run on a heavy hall structure. That is why it has been decided in many places not to change the main channel, but to make it stationary. The disadvantage here is that after each production of 0.6 to 0.8 million tons of pig iron, a refractory repair requiring several days is necessary, which must be carried out under unfavorable conditions within the casting hall. The racking in question cannot be used during this time.

The quick-change trough known from EP 0 279 165 B1 made progress here. This gutter is designed for a change option of less than 8 hours, so that the change can be made within a normal repair shift. No heavy crane is required to change; the worn gutter is lowered onto a special vehicle with the aid of hydraulic lifting devices, a newly fed gutter is picked up by a second vehicle using the same lifting devices. The gutter is cooled, broken out and readjusted under workshop conditions outside the blast furnace area.

In the main channel, the liquid metal first flows through a siphon (Fuchs) to separate pig iron and slag; after that, the slag-free pig iron flows through open, but mostly covered with plates or hoods, like the main channel, and covered with ff material to the various parking spaces of the pig iron transport vehicles. To selectively control these parking spaces, either dust sheets protected with ff material are pulled one after the other, or so-called tipping troughs come with electric or hydraulic drive.

The slag separated from the fox in turn leaves the main channel and, via open channels or channels covered with hoods, either reaches a slag pan, a pelletizer with water or solidifies through natural cooling in a slag bed made of sand.

Maintaining and keeping the pig iron and slag troughs clean is the main cause of the heavy manual work that still occurs in foundries when machines are used wherever possible.

Red dust (Fe oxide) is produced 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, appropriately large fabric and electrostatic filters are installed. A fan station must be provided in front of or behind the filters, the drive power of which can easily reach the order of a few MW, depending on the amount of suction and pressure loss in the system. The cleaned gas is released into the atmosphere via a chimney.

The disposal of the often Zn- and Pb-containing dusts requires additional facilities (e.g. pelletizing plates, intermediate bunkers) and becomes more and more problematic with increasing environmental requirements.

Overall, the dedusting devices described above require considerable investment and operating costs. It is therefore not surprising that numerous suggestions for avoiding / suppressing dust formation have been described in the literature and some have also found their way into practice.

Devices for partitioning / housing the pig iron stream by mechanical devices such as hoods, covers and the like are known.

DE 39 03 444 C1 describes a method and a device for preventing air contact of pig iron by fogging with an inert gas, e.g. B. nitrogen is known, in which the troughs leading the liquid metal are covered by the tap opening of the metallurgical furnace to form the smallest possible volume, not flowed through by the liquid metal free interior, the transfer point in which the liquid metal is passed from the transport and drain trough into a pouring vessel is shielded largely gas-tight, with both the free interior of the covered drain channels and the largely gas-tightly shielded interior of the transfer point and the interior of the pouring vessel are purged with inert gas. The liquid metal discharge jet is additionally shielded from the outlet opening into the pouring vessel by an annular pressure-inert gas jacket which prevents air from entering.

The device consists of at least one transport and drainage channel installed at a tap hole of the metallurgical furnace, a transfer station with a swivel or tilting channel and a distribution system for the liquid metal into a pouring vessel, each transport and drainage channel over its entire length one or more covering hoods has the smallest possible free, d. H. do not form the interior through which liquid metal flows.

The transfer stations including the outlet openings are largely gas-tight and shielded by a closed housing.

Nozzles for the supply of inert gas are provided in the cover hoods and in the transfer station housing.

A disadvantage of this tapping system is the thermals triggered by the high temperature of the pig iron, which requires constant replenishment of the inert gas.

The present invention has therefore set itself the task of ensuring a timely, safe and quick opening and closing of blast furnace tap holes, to suppress the formation of dust in the areas of tap hole, main channel, pig iron and slag channels, a reduction in manual work in Reach the gutter area and contribute to a reduction in investment and operating costs.

These objects are achieved in the manner as specified in claims 1 and 9. Advantageous further developments are mentioned in the subclaims.

According to the invention, a pipe section lined with ff material is arranged between the tapping on the furnace and the main channel. A stationary drilling machine and a stationary tamping machine are arranged on both sides of the pipe section. For this purpose, the pipe section itself is equipped with two connecting pieces through which the drill of the drilling machine or the trunk of the tamping machine is guided.

On the side of the pipe section facing the main channel, a ceramic slide closure is installed, as is known from steelwork technology as a closure for steel ladles. Inert gas connections with control valves are arranged directly in front of and behind the slide closure.

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

Normally, the ceramic slide valve is opened for tapping and then closed again. Immediately after closing, the tap hole is flushed out of pig iron via the inert gas connection and this state is maintained by automatically setting a small inert gas flow rate. This prevents the cast iron from solidifying in the tap hole and blocking the slide lock.

From time to time, it is necessary either to repair the tap hole washed out by the pig iron stream or to replace the ceramic plate of the slide valve.

In these repair cases, the ceramic slide valve is closed at the end of the tapping and the tap hole is flushed with inert gas through the connection of pig iron. Then the stationary drill is operated; this first drills a connection piece of hardened stuffing with which it is flanged to the pipe section itself. The drill then crosses the tap hole and drills a channel into the hardened stuffing compound, which fills the other 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, stuffing material penetrates towards the stationary drilling machine as far as the drill tip, and at the same time the stuffing material also moves onto the slide closure, but without fully reaching the ceramic slide plate, since an inert gas cushion forms in front of it.

To subsequently open the tap hole, after opening a flap that is veiled with inert gas on the top of the cover of the main channel, a second drill, which is arranged above the main channel in an inclined position - inclination approx. 6 ° according to the inclination of the tap hole - is actuated after opening the ceramic slide valve.

This drill drills the tap hole through the pipe section and through the ff lining located inside the tank. As soon as the tap hole is free, the drill is withdrawn and the flap is closed. In order to collect the unavoidable dust that occurs during this drilling process, a dedusting line is connected to the suction hood small filter system, operated only for the duration of the drilling process.

As already explained, the main channel is covered by a cover hood. The connection between the main channel and cover hood is carried out in a manner known per se so that the access of outside air to the pig iron bath located within the main channel is largely suppressed, for. B. by means of a sand cup. The cover hood can be raised and lowered mechanically and moved laterally to provide quick access to the main channel for inspections and any repairs.

At the end of the main channel is a siphon (fox) that separates the liquid metal in pig iron and slag due to their different densities. While the slag arrives in a conventional way after leaving the main channel via open or covered channels to a pelletizer, to a slag pan, to a slag pit or a slag bed, the liquid pig iron is no longer transported to the places where the pig iron transport vehicles are located usual, in gutters. Instead, multilayer metal pipes lined with ff material are used, which have an insulating layer, a permanent lining and a wear lining arranged from the outside inwards. These metal tubes are divided into lengths of 1 - 2 m, so that the relatively low weight makes handling with light lifting equipment possible. A wire mesh is placed between the wear and permanent lining; Furthermore, each pipe length has a metallic pin that penetrates the entire ff infeed from the inside out and is in contact with the molten pig iron as it flows through the pipe length. By a suitable electrical Circuit it is possible to instantly recognize when at one point the molten pig iron has consumed the wear lining to such an extent that it comes into contact with the wire mesh. The pipe length in question can be changed at the next opportunity with little effort and a freshly delivered pipe section can be used.

The pipe system is provided with appropriate branches, so that it can supply all of the designated places with pig iron. The hot metal flow is switched from one parking space to the other by means of remote-operated ceramic slide locks.

Such heating has the advantage that, on the one hand, the pig iron does not solidify and, on the other hand, there is no change in temperature for the refractory lining.

In addition, another ceramic slide closure is provided at the beginning of the pipe system behind the main channel. With this the pipe system to the main channel can be shut off. This makes it possible to heat the pipe system by a burner, ensuring that the hot burner gases heat the pipe system along its entire length; they escape at the elbows at the place where the pig iron transport vehicles are parked and not towards the main channel.

The guidance of the molten pig iron in a completely encapsulated and filled pipeline system prevents the entry of air and thus the creation of dust on this part of the transport route.

To suppress dust at the parking spaces, the pipe elbow is pulled down as far as possible (restriction: clearance profile). In order to prevent the formation of dust even with the inevitable remaining piece of free fall of the pig iron jet, an inert gas curtain is used here in a manner known per se.

By supplying the pipes with high-quality ff materials, the durability is increased. It is rarely necessary to replace the pipes. It is only carried out when the wear has reached a predetermined level. The pipes are broken out 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 equipment is required to change them, but the used main channel and the new main channel are lowered using a hydraulic lifting device, as is known, for example, from EP 0 279 165 B1.

The cooling, breaking out and repositioning of the heavy swap gutter takes place outside the casting hall under workshop conditions.
The measures described above reduce the amount of heat work and make working conditions more efficient.

The design of the blast furnace casting hall technology described above not least leads to a very substantial reduction in investment costs; the heavy casting hall crane that was previously necessary is no longer required; only light lifting gear with a small span is required. The required hall area and the steel construction weight are considerably reduced. The Elaborate hoods and piping systems for collecting dust within the casting hall are eliminated, as is the large filter system with blower station, chimney and dust silo. The operating costs are significantly reduced by a reduced effort for the operation of the filter station - maintenance, electricity costs for blowers - and the elimination of the costs for removal and disposal of the dust.

The invention is described in more detail using schematic exemplary embodiments.

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

A pipe section (3) with a connection piece (3.1) for a stationary drilling machine (4) and a connection piece (3.2) for a stationary tamping machine (5) is flanged to the tapping (1.2). A slide (6) with a ceramic plate and the inlet opening (2.1) of the main channel (2) then adjoin the pipe section (3).

After the main channel (2) with siphon (Fuchs) (11), for the separation of pig iron and slag, a number of pipe sections (12), which are lined with ff material, are gas or airtight at the outlet opening (2.2) connected, which open into a T-shaped pipe section (13). On both outflow sides of the T-shaped pipe section (13), a slide (6a) and (6b) are arranged between the downward pipe elbows (14) with an inert gas curtain (17) in order to transfer the molten pig iron to one of the positions (16a , 16b) to direct where it can drain in the pig iron transport wagon (18).

Inert gas feeds (7) are arranged on the pipe section (3) upstream and downstream of the slide (6) at the inlet opening (2.1) of the main channel (2). A further inert gas supply (7) is arranged at the outlet opening (2.2) of the main channel (2). A burner (15) for heating the pipe sections (12) is arranged in the first pipe section after the main channel (2).

Fig. 2 shows a longitudinal section through the front part of the liquid transport system. A pipe section (3) with connecting pieces (3.1, 3.2) is flanged to the tap (1.2) in a gas-tight manner, to which a second pipe section (3) with a slide (6) is connected. This second pipe section (3) is also connected gas-tight to the inlet opening (2.1) of the main channel (2). A pipe section (12) with a slide (6) is flanged to the outlet opening (2.2) of the main channel (2), to which further pipe sections (12) are added if necessary. At the end of the pipe sections (12), a T-shaped pipe section (13) is arranged, which allows the pig iron to flow into one of two pig iron transport wagons.

The main channel (2) is designed as a quick change channel. After the ff lining has worn out, it is lowered from the operating position at the level of the tapping platform onto a transport vehicle standing in the hut via pulling elements, not shown, which slide down and up on pull rods. The tie rods are fastened to the support beams of the main channel (2).

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

At the transition from the permanent lining (12.2) to the wear lining (12.3), a wire mesh (12.4) is inserted, which is connected to an electrical monitoring device via a metallic pin (12.5) in order to be able to check the condition of the wear lining (12.3).

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

A pipe clamp (3.3) is placed around the flanges of the two pipe sections (3) or (12), which is provided on each side with a feed line (3.4) with shut-off valve (3.5) and a sealing compound (3.7) in the remaining free gap between the brick pipe sections (3) or (12).

A plastic plug (3.6) is inserted into the free cross-section of the wear lining (12.3) before joining the pipe sections (3) or (12) to prevent the sealing compound (3.7) from blocking the free cross-section of the wear lining (12.3) 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

Slide closure

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)

Device for transporting liquid metal in the casting hall of a shaft furnace, in particular a blast furnace, which consists of at least one main channel with a fox, drainage channels and a transfer station installed in a tap hole, into which liquid metal transport containers or transport trolleys are made,
characterized, a) that between tapping (1.2) on the blast furnace (1) and the main channel (2) a flanged pipe section (3) with connection piece (3.1) for a drill (4) and connection piece (3.2) for a tap hole tamping machine (5) is provided and that an inert gas supply (7) and a slide (6) with a ceramic plate are arranged between the flanged pipe section (3) and the inlet opening (2.1) of the main channel (2), b) that the main channel (2) is sealed gas-tight with a siphon (11) with a cover (9) with a flap (8), c) that a slide (6) with a ceramic plate is arranged between the outlet opening (2.2) of the main channel (2) and a metal tube section (12), d) that at least one metal tube (12) is arranged between the slide (6) and the T-shaped tube section (13), e) that between the T-shaped pipe section (13) and the pipe elbows (14)
one slide (6) each is arranged. Device according to claim 1,
characterized,
that inert gas feeds (7) are provided at the inlet opening (2.1), the outlet opening (2.2) and on the flap (8). Device according to claim 1,
characterized,
that an inert gas curtain (17) is provided on the elbows (14). Device according to claim 1,
characterized,
that a stationary drilling machine (4) is provided on the connecting piece (3.1), a stationary tamping machine (5) is provided on the connecting piece (3.2) and a stationary tap hole drilling machine (10) is provided above the cover (9) on the flap (8). Device according to claim 1,
characterized,
that for sealing pipe sections (3), a pipe section with slide closure (6) and pipe sections (12) with each other, the T-shaped pipe section (13) with a pipe section (12) or with a pipe bend (14), a pipe clamp ( 3.3) with laterally arranged Supply lines (3.4) and stopcocks (3.5) are provided. Device according to claim 1,
characterized,
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, 14) at the transition from permanent chuck (12.2) to wear chuck (12.3). Device according to claim 1,
characterized,
that a burner (15) is arranged on one of the pipe sections (12). Device according to claim 1,
characterized,
that the main channel (2) is equipped as a quick change channel. Method for operating a device for the liquid metal transport in the casting hall of a shaft furnace, in particular a blast furnace, according to claims 1 to 8, and for achieving the timely opening and closing of the rack for precise metering of the liquid metal quantity in such a way a) that for opening the plugged tap hole (1.3) a tap hole drilling machine (10) after opening the ceramic plate of the slide closure (6) and after opening a closure cap (8) on the top of the cover (9) of the main channel (2) bores the hardened stuffing within the pipe section (3) of the tap hole (1.3) and the tapping (1.2), b) that after opening the tap hole (1.3) a liquid metal flow through the pipe section (3), the opened slide closure (6), the inlet opening (2.1) flows into the gas-tightly shielded main channel (2) with fox (11), that after Separating the slag the pig iron stream flows through the outlet opening (2.2) through at least one metal pipe (12) into a T-shaped pipe section (13) and from there via one of the opened slide closures (6) through a pipe elbow (14) into a pig iron transport carriage (18) arrives. c) that the tap hole (1.3) is flushed away from the liquid metal immediately after the closing of a slide closure (6) attached in the tube section (3) by means of an inert gas and that this state is maintained by the setting of a specific inert gas flow rate, d) that for the plugging / repair of the tap hole (1.3) washed out by the liquid metal current or for the replacement of the ceramic plate of the slide closure (6) the tap hole (1.3) of the tapping (1.2) is flushed out by means of an inert gas,
that the connection piece (3.1) of the pipe section (3) is drilled free of hardened stuffing compound by a drill of a stationary drilling machine (4),
that the drill of the drilling machine (4) drills a channel in the hardened stuffing material of the tap hole (1.3) and then drills the connection piece (3.2) of the tamping machine (5), e) that for the introduction of tamping material by the tamping machine (5) over the connecting piece (3.2), stuffing material within the pipe section (3) towards the tap hole (1.3), connecting piece (3.1) and ceramic plate of the slide closure (6) are moved, but the ceramic plate of the slide closure is protected by an inert gas cushion against further advancement of the stuffing material or is kept free for replacement, Method according to claim 9,
characterized,
that to avoid pig iron joint runners after repair work a tight connection of pipe sections (3), metal pipe sections (12), T-shaped pipe section (13) and pipe bend (14) by inserting a plastic plug (3.6) and a sealing compound (3.7) he follows.

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