A step closer to commercial success for Solid Oxide Fuel Cells (SOFC)
The main benefits of using SOFC, in converting primary fuels to energy, from an environmental point of view, are reduced fuel consumption (higher efficiency) and reduced emission of pollutants. Noise pollution from SOFC systems is also expected to be significantly lower than competing plants. The absence of the need for smokestacks and cooling towers make SOFC suitable for incorporation into urban sites, as low profile sub systems enclosed within buildings. As SOFC work at approximately 1000 C, there is a special need for use of high Chromium (Cr) stainless steel as system components, particularly as interconnectors. However, at such high temperatures Cr volatilisation occurs, followed by its condensation in the cooler parts of the device and its conversion into the hexavalent form of chromium, with its well known carcinogenic nature. If the operating temperature of a SOFC is decreased from 1000 C to 750 C, cheaper ferritic stainless steel could be used, containing low rates of Cr. The discussion about intermediate temperature solid oxide fuel cells (ITSOFC) and the problem of the formation of the hexavalent form of Cr no longer exists. A 3-year development and evaluation of materials and fabrication processes for ITSOFC has resulted in a successful demonstration of the components developed. New types of electrolyte and cathode powders were successfully developed. A range of catalyst materials were assessed for their efficiency and effectiveness in operation at intermediate temperature with both methane and natural gas. European SOFC manufacturers can now take advantage of the improved performance of ITSOFC due to the development of the above materials. A 45% reduction of costs compared to state-of-the-art SOFC stacks was attained.
Keywords
fuel, cells, oxide, solid, SOFC, energy, steel, stainless, methane, gas, stacks, catalysts, chromium, electrolyte, cathode, powders
