Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1100097
l`he present invention relates to a system of c~ rent
supply for aluminium-producing electrolyzers, and more
particularly to an arrangement of anode assemblies pro-
vidin~ two-sided supply of elec-tri~ current to two adjacent
electrolyzers disposed longitudinally in a row.
W~en the electrolyzers are operated at currents equal
to or more than 100,000 A, appreciable electromagnetic
forces occur w~ich bring about surface bending of the
liguid cathode metal and its intensive circulation.
~ he ma~nitude and direction of these adverse effects
of electromagnetic forces i~ largely dependent on the
arrangement of the current supply system, in particular
the anode assemblies.
Magnetic field studies recently carried out both on
pilot and production electrolyzers designed for large cur-
rents have made it possibl~ to set forth requirements for
an aluminium-producing electrolyzer current su~ply system,
giYen by :
By(O) = O; ~Y = ~ x _ O; ~ = gBx O
where By is the transverse component of the magnetic field
Bx i~ the longitudinal component of the magnetic field,
Bz i~ the vertical component of the magnetic field.
In other words, the aforementioned requirement~ boil
~own to the ~ymmetry of ~ne transYerse magnetic field,
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the invariabili~y of the values By and Bx along the electro-
lyzer axes, and the minimum value of absolute magnitude
Bz operati~e in the corners of the elec-~rolyzer, as well
as the sy~netry of the vertical ma~netic field with respect
to the elec-trolyzer axes.
In aluminium production, it is commo~ practice to
arrange electrolyzers in parallel rows. rl'he electrolyzers of
each row are connected in series, i.e., the cathode of one
electrolyzer is connected to t~e anode of the next- one. Two
techniques of supplying current to electrolyzers are known,
including one-sided anode curren~ supply and dual or two
sided anode cur~ent supply. In the case of one-sided supply,
generally a pair of anode assemblies is interposed between
two adiacent electrolyzers, tke assemblies being associated
only with o~e of the electrolyzers and supplying current to
tnis electrolyzer on one ~ide only. ~uch a c~rent suppl~
system is disclosed, for example, in the GDR Patent Specifi-
cation No.22,41&. In this system, between any two adjacen~
electrolyzers, there is provided a pair of anode assem~lies
arranged in the same vertical plane parallel to the electro-
lyzer end faces. Such a current supply arrangement, however,
is not applicable to high-power electrolyzers designed for
currents exceeding 1009000 ~, since the normal manufacturing
process o~ el~ctrolysis is ~ere disturbed on account of a
marked asymmetr~ of the magnetic field and a high mar~etic
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flu~ strength on the current supply side of the electro-
lyzer.
In the case of two-sided current supply, it is co~lon
to pro~ide four anode assemblies near each of the electro-
lyzers, in series withi~ a row, two assemblies being placed
at either end.
The known dual curre~t supply s~stem for aluminium-
producing electrolyzers (cf. FRG Patent ~o.1,'~5~,664)
comprises a plurality of anode assemblies arranged in the
spaces between any two adjacent elec-trolyzers and supplying
current thereto. ~hus, four assemblies are disposed between
two adjacent electrolyzers, two of t~em being associated
with one electrolyzer and the other two, with the next
electrolyzer. The axes of the assemblies of two adjacent
electrolyzers extend in two vertical planes paraliel to the
electrolyzer end faces, eac~ of the planes being shifted
towards a respective electrolyæer~ Since the pairs of anode
assemblies belonging to the front and rear ends of the adja-
cent elec~rolyzers, respectively, are di~erently spaced
from the transverse axes of these electrolyzers with di~fe-
rent currents ~lowing there through, the current-induced
magnetic ~ield is asymmetrical with respect to the -transverse
planes of the electrolyzers, i.e., the planes crossing the
transverse axis of the electrol~zer and normal to the current
flow. ~e mag~etic ~ield asymmetry results in a static, or
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some~imes dynamic, warping of the metal since, in that
case, the field is not symmetric with respect to the
centre of the electrolyzer either.
Eur-thermore, the arrangement of anode assemblies in
two parallel planes increases the length of the current
supply buses and, conseguently, the total le~gth of the
electrolyzer bodies.
It is an object of the present invention to provide a
current supply system for electrolyzers with two-sided anode
current supply, such as to ensure the normal manufacturi~g
process of aluminium elec-trolysi~ at currents in excess of
100,000 ~.
Another object of the inventio~ is to minImize the
adverse e~fects of the magnetic ~ield on the alumi~ium
electrolysis process.
~ further object of the invention is to reduce the
total length of the current supply buses and electrolyzer
bodies by providing a smaller spacing between the electro-
l~zer ends faces in the case of two-sided current supply
to the anode.
~ it~ this and other o~jects in view, taexe is pro~ided
a system for ~Jo-sided current supply to aluminium-producing
electrolyzers, comprising groups o~ anode assemblies dis-
posed in spaces between the ends faces o-f any two adjacent
electrolyzers and supplying current thereto, w~erein, accord-
ing to the invention, in sai~ groups of anode assemblies
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disposed in each space, all of said anode assemblies are
arranged in the same vertical plane.
In accordance with a specific embodiment of the
invention there is provided, in a dual system of current supply
for aluminium-producing electrolyzers arran~ed in series in a
row, comprises at least four anode assemblies disposed in
each space between any two adjacent electrolyzers, the first
pair of said anode assemblies being associated with one of
the two adjacent electrolyzers, and the second pair of said
anode assemblies being associated with the other one of the
two adjacent electrolyzers, an improvement consisting in that
all the four of said anode assemblies are disposed in the same
vertical plane.
The features and advantages of the present invention
will become more apparent from the following detailed des-
cription with reference to the accompanying drawing, which is
a schematic view of a dual current supply system for electro-
lyzers, in accordance with the invention.
The drawing is a schematic representation of three
electrolyzers 1, 2, 3 positioned in the centre of a row of
electrolyzers connected in series, with a two-sided arrange-
ment of current supply to the anode. Disposed between the
electrolyzers 1 and 2 are anode assemblies 4, 5, 8 and 9,
the assemblies 4 and 5 being associated with the electrolyzer
2, and the assemblies 8 and 9 with the electrolyzer 1. Dis-
posed between the electrolyzers 2 and 3 are anode assemblies
6, 7, 10 and 11, the assemblies 6 and 7 being associated
with the electrolyzer 2, and the assemblies 10 and 11 with the
electrolyzer 3.
As can be seen from the drawing, in each of the
spaces between two adjacent electrolyzers, all the four anode
assemblies, two of which are associated with one electrolyzer,
while the oth~r two with the adjacent one, are arranged in
the same vertical plane.
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Such an arrangement of the anode assemblies provides
~or a uniform distribution of the ma netic field due to
currents of e~ual intensity at either end of the electro-
lyzer.
In addition, ~uch an arrangement of the anode assemblies
permits reduc~ion of the space between any two adjacent
electrolyzers by 200 to 600 mm compared to a conventional
arrangeme~t of anode assemblies for two-sided current supply
where, as has been mentioned above, they are disposed in two
vertical planes between the electrolyzers. This reduction o~
spaces between any two adjacent electrolyzers enables the
total len~th of the row of elec:trolyzers in ceries to be
shortened by 20 to 50 m.
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