Advanced Riedhammer Carbon Baking System - A Step ... - Sacmi

Pit furnaces for the production of
Example
There is a growing demand for "larger" anodes all
Riedhammer performance spectrum. This measure
manufactured carbon are long-
Anode production:
over the world. Therefore, the increase of the furnace
brings about an additional improvement of the space
lived capital goods. As world market
leader, the Riedhammer company
in Nürnberg which has been
constructing and continuously ad-
Sections: 48
Number of fires: 3
Loading / section: 100 ta
height during a general repair is often part of the
economy and an increased yearly production output.
vancing such plants since 1924
offers also users of older furnaces
the possibility to considerably improve
the economic efficiency of
their existing plants.
The average lifetime of a closed
ring pit furnace is approx. 250
baking cycles. With a fire advance
of 28 hours this means a durability
of approx. 13 years. Riedhammer
has developed a patented and
well-proved procedure for
executing repairs and structural
improvements on a closed furnace
during operation. Contrary to a
shutdown of the furnace for repair,
1. Standard operation
Fire advance: 28 h
Yearly output: 93,857 tba
2. Repair during operation
Duration of repair (approx.): 150 days
Fire advance 2 during repair: 48 h
Yearly output (approx.) 3 : 77,786 tba
Production loss
compared to standard operation (approx.): 16,071 tba 17%
3. Repair of shut down furnace
Duration of repair (approx.) 1 : 150 days
Fire advance: 0 h
Yearly output (approx.) 3 : 55,286 tba
Production loss
compared to standard operation (approx.): 38,571 tba 41%
Picture: Temperature homogeneity in the section
TEMPERATURE HOMOGENEITY IN THE SECTION
while considering all 3 axes.
The temperature homogeneity on the Y-axis is
achieved by:
Flow and thermodynamic analyses of the flue gases
in the section, e.g. in a section model and realisation
of the gained knowledge by modifying the brickwork
/ adapting the pit walls and fire shafts and thereby
optimising the flow conditions.
Due to the optimised geometry, the use of fibre-lined
light weight section covers leads to a better
distribution of the flue gases and thus also to an
improved temperature homogeneity on the X-axis.
this version offers considerable
1 depending on some specific conditions; 2 typical value; 3 deviations are possible
advantages:
The first step towards repair or "retrofit" is a detailed process in the Riedhammer Research and
inspection of the furnace. During this inventory the Development Centre.
condition of the complete plant is examined, the After the evaluation definite proposals in view of
scope of a possible reconstruction is determined and
§ output increase,
the baking process is analysed.
§ temperature homogeneity and, in consequence,
product quality improvement,
Structural modifications of the geometry and the use
§ energy saving,
of improved materials have a considerable influence
on the efficiency of the plant. The basis for possible § reduced operation costs and
reconstruction measures are thermodynamic § improved environmental protection are
examinations and developments derived from this elaborated.
OUTPUT INCREASE
Example
Output increase by modifying the section geometry
For example a brickwork
modification may bring about a
1. Per section
Before reconstruction: 90 anodes/section resp. 82.20 t/section
much more favourable "space After reconstruction: 105 anodes/section resp. 96.60 t/section
utilisation" (relation between
product and installed refractory
2. Per year
Before reconstruction: 32,850 anodes/section resp. 30,222 t/section
material).
After reconstruction: 38,325 anodes/section resp. 35,259 t/section
Total output increase: 5,037 t/section
Structural changes on the flue gas transfer bend
between fire shaft and flue gas ring mains bring about
more uniform and efficient flow conditions in the
preheating zone and therefore also contribute to an
improved temperature homogeneity on the X-axis.
Picture: Light-weight section cover
Burner manifolds adapted to the individual baking
processes for most different heating media (natural
gas, coke gas, heavy oil etc.) permit an improved
temperature homogeneity in the main baking zone.
This is realised by an individual control of the respective
burners. Several thermocouples per cover are
determining the basic figures for the process
command system. The result is a favourable fuel
consumption.
A positive influence on the temperature homogeneity
on the Z-axis can be achieved by optimising the
baking profile.
Picture: Flue gas transfer bend