Note: Descriptions are shown in the official language in which they were submitted.
CA 02550880 2006-06-23
Engelhardt & ~ngelhardt
Patentanw~lte
innovatherm
Praf. Dr. Leisenberg GmbH t Co. ICG
35510 Butzbach
Management process for an open anode furnace
The present invention relates to a management process for an open anode
furnace
in accordance with the pre-characterising part of Clause 1. as well as to a
device for
measuring the operating status of an open anode furnace and for managing its
process in accordance with the pre-characterizing part of Clause 5.
Ts date, an open or covered anode furnace has been operated in such a way that
the specialist personnel operating the anode furnace have to rely on many
years of
professional experience to enable the workers to control the anode furnace.
This
means that the specialist personnel responsible for operation regulate the
burner
power, for example, in order to increase or reduce the temperature in the
burner
zones. The temperature is measured at various points in xhe anode furnace for
this
purpose.
However, an anode furnace control method of this type has the disadvantage
that the
specialist personnel are often unable to achieve the optimum operating setting
of the
anode furnace because information is lacking. This is because the parameters
that
are decisive in terms of optimum energy utilization can only be inadequately
assessed and estimated by the specialists. For example, it is conceivable that
an
obstacle could occur within the air duct that could under certain
circumstances cause
a local reduction in the volume of air passing through this area of the anode
furnace,
leading to a rise in temperature wheroas there may be a drop in temperature at
CA 02550880 2006-06-23
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another point. Even increasing the burner power has no effect in the event of
a
reduction in the throughput of air in the area of the burner, because the
lower amount
of heating air available does not transport the additionally input burner
energy to the
anodes immediately with the effect that the burner energy is applied to the
walls of
the anode furnace_ This, however, leads to significant damage to the anode
furnace
because the walls of the anode furnace are not designed to withstand such an
elevated level of heat stress.
Furthermore, it is disadvantageous that the personnel operating the anode
furnace
cannot reliably estimate at what moment a section of the anode furnace has
laecome
unusable and therefore must be renewed. Instead, such decisions have in the
past
been based on statistical observations and values drawn from experience, which
in
some cases has led to a section being renewed too soon or even too late. This
causes unnecessary operating costs because the energy consumption increases.
Furthermore, it is highly costly to operate a faulty section or a section
which is not
being used optimally in terms of energy because the anode furnace requires
additional energy in order to burn the anodes it 'contains.
To date, no device far automatic control of a.n anode furnace has been
disclosed.
It is therefore the task of the present invention to provide a management
process for
an anode furnace of the aforementioned type, by means of which the anode
furnace
can be operated automatically over a relatively long period. This process is
intended
to provide measuring parameters by means of which an electronic control unit
automatically undertakes the process management of the anode furnace. Also,
the
service life of the anode furnace should be extended because the process
management remains within an optimum energy band. Furthermore, it is the task
of
the present invention to provide a device by means of which the process
management of the anode furnace can be undertaken.
The task in accordance with the present invention for managing the process of
the
anode furnace is accomplished by the features of the characterizing pacts of
patent
claims 1 and 5, and the task for automatic process management of the anode
2
CA 02550880 2006-06-23
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furnace is accomplished by the device in accordance with the characterizing
park of
patent claim 6.
Further advantageous embodiments of the invention are apparent Pram the'
subordinate claims.
By means of the device and process in accordance with the present invention,
it is
possible to measure a heating duct index that is permanently adjusted to the
actual
operating situation in the anode furnace. In this case, an electronic control
unit
allocated to the device evaluates the measurement results and compares these
with
a predefined or mathematically calculated actual operating condition, and
adapts the
actual operating status to the optimum actual value of the anode furnace. This
provides an advantageous way of obviating the need for specialist personnel in
order
to monitor and conduct the process management of the anode furnace. Rather,
the
process management of the anode furnace can be based on precisely predefined
values so as to make it possible to operate the anode furnace with optimum use
of
energy.
Also, the relevant parameters are determined in each section of the anode
furnace
so that it is possible to verify clearly in which section which actions have
to be taken.
For example, the electronic control unit increases or reduces the air
throughput
through the anode furnace in accordance with the volume of air actually needed
in
the individual zones. If necessary, it is also possible to increase or reduce
the
quantity of fuel in order to control the output of the burners so as to
achieve the
optimum energetic temperature required for combustion of the anodes.
Consequently, the process management of the anode furnace takes place fully
automatically and requires only minor manual checks, for example to see
whether
the measuring instruments used are in need of repair and that they are
delivering
correct measurement values. As a result, a fully automatic furnace process
management of this kind only requires a small number of personnel which allows
considerable personnel cost savings. In addition, process management is
adapted to
3
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achieve an optimum energy profile and therefore the energy Consumption can be
reduced to the magnitude required for optimum operation of the anode furnace.
The drawing shows a sample embodiment configured in accordance with the
present
invention, the details of which are explained below. In the drawing,
Figure 1 shows an anode furnace consisting of three fires divided into three
zones, within which a plurality of anodes are placed, with a schematic
process management diagram for managing the process of the anode
furnace, as a plan view,
Figure 2 shows the anode furnace in accordance with Figure 1, as a side view,
together with a temperatureltime curve configured for the process
management of the anode furnace,
Figure 3 shows two adjacent sections of the anode furnace in accordance with
Figure 1, as a magnified plan view, and
Figure 4 shows a cut-out of the anode furnace in accordance with Figure 1 and
its sections, to which certain actual operation conditions are allocated.
Figures 1 to ~ show an 2~ns~de furnace 2 to which a device 1 for process
management
is allocated. The device 1 is intended to allow the anode furnace 2 to be
controlled
automatically without the need for extensive monitoring activity by the
operating
personnel.
The anode furnace 2 shown in Figure 1 consists of three individual fires with
an
identical structure. The structure and the mode of function of the anode
furnace 2 is
explained in more detail using the first fire. Each fire can be divided into
three zones
3, 4 and 5 within which different operating Conditions obtain. A plurality of
anodes 7
that are to be burned are placed in one section 6 each in zone 3. In zone 4,
the
positioned anodes 7 should be burned by three burners 10 and the burned anodes
should cool 7 in zone 5.
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This means it is necessary for air to be channeled through the anode furnace 2
and
through the three zones 3, 4 and 5. An air duct 9 is provided in the anode
furnace 2
for this purpose and it connects the individual sections 6 and therefore also
the zones
3, ~4 and 5 with one another. Furthermore, one damper flap 13 each is provided
at the
output and input of the air duct 9 in order to allow the quantity of air
sucked into the
air duct 9 to be controlled. A ventilator 14 is allocated to zone 3 and to the
air duct 9
emerging there, by means of which the air is drawn through zones 3, 4 and 5 so
that
negative pressure exists in the anode furnace 2. Consequently, air enters zone
5 of
the anode furnace 2 with the norms,! room temperature of the surrounding area
and
cools down the heated anodes 7. Nevertheless, there is a heat exchange between
the anodes 7 and the sucked-in air, with the result that the air flowing into
zone 4 is
heated up. The three burners 10 further heat the air in zone 4, so that the
anodes 7
placed there are exposed to the operating temperature required for combustion.
The air flowing onwards into zone 3 therefore has a further elevated
temperature,
resulting in the anodes 7 placed in zone 3 being preheated.
Once the anodes in zone 4 have been burned up, the burners 10 are moved and
transferred to zone 3 in order to burn the anodes 7 placed there. In this way,
the
anode furnace in its entirefiy represents a closed control loop in which the
following
procedures occur in a recurring sequence: the three fires burn the positioned
anodes
7, the anodes 7 cool down and the anodes 7 are preheated; in a further three
zones,
meanwhile, the anodes 7 can be placed for burning or the burned anodes 7 can
be
removed frpm the anode furnace 2.
In order for the furnace management process to be performed automatically, an
electronic control unit 12 is allocated to each individual fire In the anode
furnace 2.
Furthermore, each of the sections 6 that form zones 3, 4 and 5 contains
temperature
sensors 1 G, sensors 17 for measuring the air throughput and sensors 20 for
measuring the opacity of the air, by which is meant the obtaining soot
particle
concentration in the air. Temperature sensors 16 and sensors 17 and 20 record
measurement values for each of the sections 6 and pass these an to the
electronic
control unit '12.
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~'he values measured in this way are used by the electronic control unit 1,~
for
creating a heating duct index that is made up of the measured temperature
andlor
the measured volumetric flow of air and/or the quantity of fuel supplied and
the
combustion capacity of the burners 10 andlor the opacity of the fire generated
by the
burners 10 andlor the level of negative pressure obtaining in the zone 3, 4, 5
andlor
the resulting temperature gradient of the fire generated by the burners 10_
This
heating duct index is now compared with an actual operating value of the anode
furnace 2 that has an optimum energy level. The electronic control unit 12
makes
appropriate adjustments in case there are discrepancies. Following this, the
heating
duct index is once more compared with the actual operating value.
The heating duct index is adjusted to the actual operating value by the damper
flap
13 at the entrance to the air duct 9 being opened or closed further, for
example, with
the effect that either more or less air enters the anode furnace ~, (f
necessary, the
burner power of the burners 10 can also be adjusted by reducing or increasing
the
quantity of fuel. Controlling the ventilator 14 is also another way of
increasing or
reducing the air throughput. There are also individual dampers 13 in the
inside of the
anode furnace 2 inside the air duct 9, which means that, in principle, each
section 6
can be individually supplied with air.
Figure 4 in particular shows that the individual sections 6 are monitored with
the
efFect that it is possible to measure precisely which of the sections 6 are
running with
optimum energy utilizs,tion, or which of the sections 6 may be damaged as a
result of
the permanent stress caused by fluctuations in temperature and will have to be
renewed. These sections 6 are shown as a black field in Figure 4, which ,means
the
operating personnel can easily find out which of the sections 6 will have to
be
completely renewed in the next cooling-down phase in order to achieve an
optimum
use of energy during operation.
16 IVlay 2006
A 54'2 CA ve-alri
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