Dr. M. Hanel, Dr. A. Filzwieser, Dr. I. Filzwieser, DI S. Wallner, S. Ruhs
The productivity of furnace operations has been dramatically increased over the last decades by
using effective cooling solutions. For a given system in terms of heat input, material composition,
oxygen enrichment amongst other aspects, the performance of a furnace is depending on the availability
of the entire reactor. The limiting factors of furnace availability might be manifold. In particular,
they can however be related to high refractory wear areas in the slag zone or tapping areas. Other
areas experiencing severe corrosive attack can also cause a decrease in performance [1 – 3].
Water as the conventional cooling medium is very risky in certain areas since a leakage would result
in an immediate explosion causing severe damage within the furnace structure. A best-case
scenario would be a production loss as a consequence of major repair work. As a worst-case scenario,
personal injury and fatal accidents have a high probability. Known accidents from all over the
world in every area where water is used as a cooling medium are evidence of this fact. The only
effective alternative of eliminating this risk and stop using water is the approach employing the ionic
liquid cooling technology (ILTEC) [4, 5].
With the novel ionic liquid cooling technology virtually all negative effects of a water cooled system
are eliminated and additional benefits can be provided. By definition, ionic liquids (IL) are salts
with a liquidus temperature below 100 °C. They have no noticeable vapour pressure below their
thermal decomposition point and – depending on the actual composition – there is just a minor or
absolutely no reaction with the liquid melt or slag. Furthermore, the temperature range for cooling a
system is much wider than water. The special ionic liquid IL-B2001 can be operated from 50 °C up
to 200 °C. This allows the recovery of energy. Additional benefits resulting from this relatively high
cooling medium temperature are that hydration and corrosion problems are avoided.
Overall it is utmost important for industrial applications that the requirements regarding critical heat
flux, thermal limits and impacts of health, safety and environment have to be fulfilled. Major data
of the ionic liquid IL-B2001 for cooling are provided and discussed. This, and its commercial operation demonstrate that the ionic liquid IL-B2001 and the ILTEC Technology can lead to an industrial change regarding safety standards by becoming the new best available technology (BAT) .
Until today industrial realized projects comprise of the cooling of a tap-hole at a blast furnace
(ArcelorMittal Bremen GmbH, Germany), the cooling of the side walls of zinc oxide furnace
(Nyrstar, Norway) and the cooling of flanges of a RH-facility (voestalpine Stahl Donawitz GmbH,
Austria). They are described and new applications are presented.