SMS SIMAG
SMS Siemag presents a new electric arc furnace S/EAF for
continuous operation
30 percent higher productivity with lower energy
consumption.
The electric arc furnace is the core unit of an electric
steelmaking plant and has a decisive impact6 on annual production and energy
costs. A new development from SMS Siemag, Germany, is the ARCCESS steady EAF
(S/EAF), which allows real continuous operation for up to one week. The S/EAF
has been newly developed from scratch and combines innovations with proven
technology. This technology arises from SMS Siemag’s long-standing experience
in the fields of submerged -arc furnaces (SAF) with over 300 references,
electric arc furnaces (EAF), with over 1,300 references and CONARC technology.
The result is a new type of electric arc furnace,
yielding a 30 percent higher productivity with lower energy consumption thanks
to its reliable continuous process. The integrated energy recovery system
futher improves the efficiency by
utillzing the energy of the hot furnace off-gas.
All components have been designed to allow continuous
power-on operation for around one week. Uninterrupted operating practice is
made possible by a patented system derived from SAF technology,
Which allows the electrode to be clamped and slipped
continuously.
Whenever an electrode has been used up, a fresh piece of electrode is joined
on at its end. Both operations take place under ‘’Power-on’’.
‘’Continuous operation in SAF s is only made possible by
the electrode slipping device, which in these furnaces represents proven
technology long since. That this principal will now be transferred into the new
S/EAF is a real innovation and it
definitely results in an increased efficiency, ‘’ says Prof. Bernd Friedrich at
the institute for Machine Elements and Machine Design at RWTH Aachen
University.
Similarly to the operation of a submerged-arc furnace,
the process takes place in a uniform way and is almost free of fluctuations
since the S/EAF is operated continuously in the flat bath phase with liquid
initial bath. The geometry of the new furnace shell has been optimized
accordingly and comprises a flat lower shell and a conical furnace roof placed
closely on top. The S/EAF is operated continuously charged with direct-reduced
iron ore (DRI/HBI), hot metal or scrap through a material handling system that
is also rated for the use of 600 C hot DRI.
In addition to the electrodes, water-cooled oxygen
blowing lances are introduced throught the furnace roof. This technology has
been adopted from CONARC, a furnace unit developed by SMS Siemag with the aim
to rapidly decarburize melts with high carbon content. The level of foaming slag is controlled by a new, patented
slag door system. The steel is tapped slag-free and likewise under
‘’power-on’’.
Since the S/EAF is not opened during operation, no roof
hood for the secondary gas collection is needed. Primary gases are directly
exhausted through a furnace nozzle. This allows the connected gas cleaning
plant to be dimensioned much smaller. The power-off times that previously
affected the EAF no longer arise. Continuous operation is interrupted only for
regular maintenance work . For that
purpose the lower furnace shell can also
be driven to a maintenance stand. Heavy-duty
gantry cranes with elaborate building structures and foundations are not
needed.
The steady input of electrical energy and the flat-bath
process prevent negative feedback on the electricity grid (for example
flickers). Further advantages are the protection of the refractory lining and
lower specific electrode consumption.
With more than 1,700 references, SMS Siemag is the market leader in the field of
electric arc furnaces (EAF) and submerged-arc furnaces (SAF).
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