Note: Descriptions are shown in the official language in which they were submitted.
CA 02677975 2009-08-12
BURNER ARRANGEMENT
Technical Field
The invention concerns a burner arrangement, especially
for heating, drying and/or keeping hot especially tundishes of
a continuous casting installation.
Prior Art
In melting operations, for example in steelworks with
continuous casting installations, the molten metal is usually
brought by a ladle to the casting platform of a continuous
casting installation. The hot liquid metal is intermediately
buffered by means of a tundish, for example a tundish launder,
before it flows into the mold of the continuous casting
installation. The tundish also serves the purpose of allowing
continuous changing of the casting ladles, thereby making it
possible for sequence casting of the metal to be carried out.
The tundishes are usually relined on a cyclical basis
and, if necessary, subjected to fresh intermediate repair work
and fitted with an immersion tube before each sequence. The
tundish is then dried and heated. The heating is carried out
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by operating a burner with fossil fuels, such as natural gas,
and with oxygen carriers, such as air. Commerc:_ally available
burners, which are built into a heating cover, are usually
used for this purpose.
The use of commercially available burners that produce
flames results in the generation of fast-moving exhaust gas,
which tends to cause striation and as a whole has a low
fraction of radiant energy.
The flames produce point-focal heating, which can lead to
local overheating, where each flame strikes directly, while
other areas tend to be heated too weakly, where the flame is
too far away. This causes stresses in the tundish, which can
lead to cracking and thus to stoppage of the entire plant. In
addition, due to the inhomogeneous heating with the flame, the
drying time is prolonged, the service life of the tundish is
reduced, and at the same time the energy consumption is very
high. CO2 emissions are also very high. This also increases
the consumption of lining material for the tundish, because it
must be replaced more often due to increased cracking. This
results in higher costs for the energy supply, which makes the
plant less economical. Furthermore, the discharge of
combustion exhaust gases is very high, which on the whole is
not very environmentally friendly and in recent years has come
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to be seen as especially unfavorable in connection with the
discussion of the greenhouse effect.
Burner arrangements of this type are disclosed, for
example, by KR 102003005373 A, KR 1020030021728 A, KR
1020040011716 A, KR 1020010091068 A, and KR 09122854 A.
Description of the Invention, Objective, Solution,
Advantages
The objective of the invention is to create a burner
arrangement, especially for heating, drying and/or keeping hot
especially tundishes of a continuous casting installation,
which realizes better utter utilization of the energy that is
used, a reduction of C02 emissions, a high availability of the
installation. A further objective of the invention is to
create a method for the advantageous control of a burner
arrangement.
The objective of the invention with respect to a burner
arrangement is achieved with a burner arrangement, especially
for heating, drying and/or keeping hot especially a tundish of
a continuous casting installation, with a flat arrangement of
at least one burner, where the burner or burners are designed
as porous burners.
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In this regard, it is especially advantageous if the
porous burner has porous burner segments. The porous burner
can have one segment or a plurality of segments, which are
connected with one another or at least are arranged adjacent
to one another except for a slight joint between the segments.
In accordance with the invention, the connected segments are
connected by connecting means and/or are held, for example, by
means of a frame in such a way that a uniform burner is
realized by the arrangement of the segments adjacent to one
another. In one advantageous embodiment, it is effective if
the segments of the porous burner have a flat arrangement in
adjacent rows.
To supply fuel and an oxygen carrier, it is effective if the
porous burner segments are each supplied with fuel and/or an
oxygen carrier by means of supply lines. In this regard, it
is advantageous if at least some of the individual supply
lines are supplied with fuel and/or with an oxygen carrier by
a common supply line. It is also advantageous if, in
accordance with another embodiment, a blower is provided to
supply the oxygen carrier through the supply lines. In this
way, an oxygen carrier, for example, air, is conveyed through
the supply lines to the segments by means of the blower.
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To manipulate the burner arrangement, it is advantageous
if the porous burner arrangement is held by a swivel mount or
a swivel arm, which has a joint that allows it to swivel. In
this connection, it can be advantageous if, in accordance with
another embodiment, the blower is likewise held by the mount
or the swivel arm, so that the blower can also be swiveled.
The objective of the invention with respect to a method
is achieved by a method for controlling a burner arrangement,
in which segments of the porous burner are turned on and/or
off as a function of the desired heating intensity or heating
power. In this regard, it is advantageous if segments are
turned on or off at least in alternating rows or in a
checkerboard pattern.
Advantageous refinements of the invention are described
in the dependent claims.
Brief Description of the Drawings
The invention is explained in greater detail below with
reference to the embodiment of the invention that is
illustrated in the drawings.
-- Figure 1 is a view of a burner arrangement of the
invention for heating and/or drying a tundish and/or keeping
it hot.
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-- Figure 2 is a top view of a burner arrangement
according to Figure 1.
Preferred Embodiments of the Invention
Figure 1 shows a view of a burner arrangement 1,
especially for heating, drying and/or keeping hot especially
tundishes of a continuous casting installation. In this
regard, the burner arrangement 1 has a burner 2, which is held
on a mount 3 and is designed to swivel by virtue of the fact
that the mount 3 has a swivel bearing 4. The mount thus forms
a swivel arm. In this regard, the burner can be positioned
over the tundish 5, as in heating position 8, in which it
heats the tundish, or the burner can be swiveled upward into a
parked position 9, so that it is in an essentially vertical
position, and the tundish is essentially freely accessible for
other work. The swivel arm can be swiveled between these two
positions by hydraulic or pneumatic control.
In accordance with the invention, the burner 2 is
designed as a porous burner 10. The porous burner 10 has the
advantageous property that, as a gas burner, it allows
combustion of a gas-air mixture in a porous structure or cell,
which gets by to a certain extent or totally without the
formation of a flame. As a result, flameless, volumetric
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combustion of the gas-air mixture is achieved. In this
process, combustion in the porous structure is realized, so
that after the introduction of the gas-air mixture, a strearn
of exhaust gas is produced as the reaction product on the
discharge side.
The oxygen carrier, for example, air, is blown into the
porous burner 10, for example, by means of a blower 6. In
this process, the oxygen carrier is drawn in by the blower and
supplied to the burner, which is designed as a porous burner
10, by supply channels or supply lines 7.
It is advantageous for the porous burner 10 illustrated
in Figure 2 to be composed of several segments of the porous
burner. To this end, the individual segments 11, 12, 13 have
an essentially flat arrangement and are connected to at least
one supply line 14, 15, by means of which the fuel and/or the
oxygen carrier is fed to each segment. In this regard, the
air or the oxygen carrier can be introduced into the segments
of the porous burner by a blower, as described above. In
accordance with another embodiment, it is also possible to
provide a supply line for a fuel-air mixture.
The segments, which have a flat arrangement, are
advantageously arranged adjacent to one another for this
purpose with slight joint spacing, so that a flat arrangement
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of the porous burner segments in several rows is provided.
The segments of the porous burner can be supported by
supporting means, for example, in a support frame, which is
connected with the swivel arm, so that the flat arrangement of
the porous burner segments can be swiveled together with the
swivel arm.
The porous burner produces a stream of hot exhaust gases
as well as thermal radiation, which are directed at the
tundish to heat it, to dry it, to warm it, or to bring it to a
desired temperature. The hot exhaust gas reaches the interior
of the tundish or the surface of the tundish, which produces a
homogeneous temperature distribution and thus counteracts
striation. However, due to the fact that a large portion of
the energy is converted to radiation, the tundish can also be
,
heated very effectively.
It is especially advantageous that the porous burner is
realized as an essentially flat arrangement composed of
individual segments of porous burners. This provides the
advantageous possibility of controlling the process by turning
individual segments or rows of segments on or off
independently of one another or turning individual segments on
or off independently of one another.
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Depending on the heating intensity or heating power to be
applied, all of the segments of the porous burner can be
turned on, or some individual segments can be turned off. It
can be advantageous if segments are turned on or off at least
in alternating rows. It can also be advantageous if segments
are turned on or off alternatingly in a checkerboard pattern,
so that only a fraction of the segments is operated.
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List of Reference Numbers
1 burner arrangement
2 burner
3 mount, swivel arm
4 swivel bearing
tundish
6 blower
7 supply channels or supply line
8 heating position
9 parked position
porous burner
11 segment
12 segment
13 segment
14 supply line
supply line
