Extended Arc Furnace
A new development in plasma furnace technology in which by relatively simple modifications a more or less conventional arc furnace can be made to produce a long stable plasma flame is described. A very promising application of this technique is in the steel melting as well as in direct reduction of fine iron ore, waste oxides, flotation concentrates, blast furnace dust, fly ash, mill scale, etc.
Hematite reduction by hydrogen plasma: Where are we now?
Currently, iron is extracted from ores such as hematite by carbothermic reduction. The extraction process includes several unit steps/processes that require large-scale equipment and significant financial investments. Additionally, the extraction process produces a substantial amount of harmful carbon dioxide (CO2). Alternative to carbothermic reduction is the reduction by hydrogen plasma (HP). HP is mainly composed of exciting species that facilitate hematite reduction by providing thermodynamic and kinetic advantages, even at low temperatures. In addition to these advantages, hematite reduction by HP produces water, which is environmentally beneficial. This report reviews the theory and practice of hematite reduction by HP. Also, the present state of the art in solid-state and liquid-state hematite reduction by HP has been examined. The in-flight hematite reduction by HP has been identified as a potentially promising alternative to carbothermic reduction. However, the in-flight reduction is still plagued with problems such as excessively high temperatures in thermal HP and considerable vacuum costs in non-thermal HP. These problems can be overcome by using non-thermal atmospheric HP that deviates significantly from local thermodynamic equilibrium.
Stability of planar PEMFC in Printed Circuit Board technology
Abstract The use of planar PEMFCs in printed circuit board (PCB) technology with a thickness of less than 3.5 mm are presented. This planar design consists of an open cathode side which allows a completely passive, self-breathing operation of the fuel cell. Power densities of 100 mW/cm 2 at 500 mV with hydrogen as a fuel were achieved. A steady operation with this type of fuel cell was demonstrated over a week without any cell flooding. Since the electrical conducting elements of PCBs usually are made of copper, corrosion in the wet environment of a PEMFC is expected. Thus, a significant degradation in performance of fuel cells made of plain copper PCBs was seen in long-term operation. In order to avoid corrosion, the copper layer has to be coated. Fuel cells in PCB design with diverse coatings were tested in long-term operations up to 1000 h under load. Moreover, corrosion currents have been determined by the use of potentiodynamic scans. Promising coatings are electroplated Cr and Ni and a combination of Ni/Au.