special - ALUMINIUM-Nachrichten – ALU-WEB.DE

ALUMINIUM SMELTING INDUSTRY
KPI
Unit
D18+, 1 June
to 21 Nov 2012
D18
Difference
Amperage kA 202 202 0
Current efficiency % 96.0 92.3 3.7
Metal production kg/pot-day 1,562 1,502 60
Volts per cell V 4.08 4.69 -0.61
DC specific energy kWh/kg Al 12.67 15.14 -2.47
Fe % 0.05 0.07 -0.02
Si % 0.02 0.03 -0.01
AE frequency AE/pot-day 0.02 0.44 -0.42
AE duration (V > 8 V) s 32 31 1
PFC emissions,
CO 2 equivalent [4]
kg/ t Al 12 247 -235
Table 4: D18+ and D18 performance comparison. D18+ is average of 5 middle pots
tion from D18 to D18+ cell design. Additionally,
the original potshell was modified to accommodate
two more cathode blocks. Fig. 3
shows the seven test cells. Table 4 gives key
performance indicators. The performance of
the D18+ cells has now exceeded the original
design targets, resulting in significant improvement
over the existing D18 cells. The
test cells are currently being fully evaluated
before implementing throughout Dubal’s
D18 potlines.
Conclusions
DX+ cell technology continues to give excellent
performance with considerable amperage
increase to 440 kA in DX+ pilot cells.
The new DX+ Pot Control System is based
upon standard market PLCs, which give increased
HMI capabilities and ensure easy
maintenance and future development.
The successful test and validation of the
D18+ cell technology has proven that it is
both technically and practically possible to
update and replace the cell technology within
an existing operating potline. Study of the
feasibility and optimal engineering pathway
is currently in progress to enable replacing
the remaining 513 D18 cells with the D18+
technology.
References
Fig. 4: Completed seven D18+ test cells in a D18 potline
been developed to modernise the original
Dubal D18 potlines and to improve their performance
and economic competitiveness [8].
The objectives behind modernising the cells
through new technology are to reduce the
specific energy consumption to below 12.9
kWh/kg Al, reduce the anode effect frequency
to below 0.10 per cell-day and to allow for a
possible further amperage in-crease of 40 kA.
The constraints were: to maintain the same
cell-to-cell centerline
distance and
the same cell
height, to keep
the amperage
availability limits
within the same
rectifiers and to
use the same gas
treatment centre.
Seven D18+
cells were constructed
and successfully
startedup
in March 2012.
Table 3 gives a list
of changes made
during the transi-
[1] Ali Al Zarouni et al., DX Cell Technology Powers
Green Field Expansion, Light Metals 2010, 339-
343.
[2] B.K. Kakkar et al., Commissioning of Emirates
Aluminium Smelter Potlines, Light Metals 2012,
721-726.
[3] Ali Al Zarouni et al., The Successful Implementation
of Dubal DX Technology at Emal, Light Metals
2012, 715-720.
[4] Ali Al Zarouni et al., DX+ an Optimized Version
of DX Technology, Light Metals 2012, 697-702.
[5] M. Reverdy et al., Advancements of Dubal High
Amperage Reduction Cell Technologies, Light Metals
2013.
[6] Abdalla Zarouni et al., Mathematical Model
Validation of Aluminum Electrolysis Cells at Dubal,
Light Metals 2013.
[7] Abdalla Zarouni et al., Achieving Low Greenhouse
Gases Emission with Dubal’s High Amperage
Cell Technology, 19 th International Symposium IC-
SOBA, Belem, Brazil, 25 Oct. to 2 Nov. 2012.
[8] S. Akhmetov et al, D18+: Potline Modernisation
at Dubal, Light Metals 2013.
Author
Michel Reverdy is Technology Transfer manager at
Dubal.
22 ALUMINIUM · 1-2/2013