Blast furnace technology and biomimetic surfaces
As a rule, blast furnaces, reducing iron ore to raw iron, and steel-mills form an integrated chain of production units. Therefore, the failure of one chain link causes an unproductive waist of energy and other resources (e.g. coke).
Being at the base of the production chain, the standstill of blast furnaces has a high leverage effect. The main source of blast furnace downtime are burnt through tuyeres. Tuyeres are water cooled ducts through the blast furnace wall that allow to inject huge amounts of hot (around 1.200°C) air into the blast furnace in order to maintain the chemical processes transforming iron ore to raw iron. Prolonged contact between tuyere and liquid iron may destroy the tuyere – despite cooling. In Germany, the annual energy losses due to tuyere failure amount to 1.600 TJ which corresponds to an – in principle avoidable – CO2-output of about 200 000 t (i.e. roughly 0.2‰ of the German CO2-production in the year 2013).
The research project „Steigerung der Energieeffizienz beim Hochofenbetrieb durch Erhöhung der Anlagenverfügbarkeit mittels neuartiger Longlife-Blasformen [Increase of energy efficiency of blast furnaces by using novel longlife-tuyeres]” (sponsored by the Federal Ministry of Economy and Energy) addressed these problems by developing tuyere surface structures which are able to accommodate air cushions. These reduce the heat input into the tuyeres and – consequently – tuyere failure dramatically. Although the project had a pure engineering background the starting point for the theoretical considerations was the skin structure of springtails (Collembola). Their body surface is – due to a network of air trapping indentations – extremely water repellent. The predictions of the resulting theory proved to be quite reliable, allowing to keep the experimental efforts low.
A proposal aiming at similar objectives – the optimisation of energy and resouces in certain production processes in heavy industry – is being reviewed at the moment.
Contact:
PD Dr. Dr. Wilfried Konrad (email)
Collaborators:
VDEh-Betriebsforschungsinstitut GmbH, Sohnstraße 65, 40237 Düsseldorf
Lebronce Alloys GmbH - Hundt & Weber, Birlenbacher Straße1, 57078 Siegen
In 2017, the project was awarded with the Materialica Gold Award in the category "Surface and Technology".
Selected Publications:
Nickerl, J., Helbig, R., Schulz, HJ., Werner, C., Neinhuis, C. Diversity and potential correlations to the function of Collembola cuticle structures. Zoomorphology (2013) 132: 183. DOI: 10.1007/s00435-012-0181-0
W. Barthlott, M. Mail, C. Neinhuis. Superhydrophobic hierarchically structured surfaces in biology: evolution, structural principles and biomimetic applications. Phil. Trans. R. Soc. A (2016) 374: 20160191. DOI: 10.1098/rsta.2016.0191