Papers by Author: Dario Montinaro

Abstract: In the present work, the melting behaviour of ashes obtained from the combustion of coals from different seams were investigated by a laboratory-scale equipment. The ash melting behaviour was studied by heating the specimens in a tubular furnace under a controlled gas atmosphere, while continuous monitoring the shape transformation by a digital camera. The ash fusibility temperatures (AFT) were determined by using an application which allows the in-line identification of the AFT-related shapes specified in the ASTM D 1857-04. The effect of the furnace gas-atmosphere on the determination of the ash fusion temperatures were studied by performing the measurements under dry-air, SO2-rich-air and humidified air environments. It was found that under dry conditions, AFT determination is significantly affected by slag foaming, leading to an overestimation of the melting temperatures. Low water vapour concentrations does not appreciably change the results obtained under dry air, while SO2-rich atmosphere seems to reduce foaming. As a result, since no volume expansion was observed, samples heated under SO2-air flow, apparently melt at lower temperatures with respect to dry air conditions. The mineral phases transformation of the ashes during the heating process was studied by X-Ray diffraction and it was found that the low temperature transformations are essentially related to Iron and Alkalis reaction with aluminosilicates to form a glassy phase. On the other hand, high temperatures transformations are related to quartz and mullite solubilization which is closely dependent to the amount of Calcium, and therefore of anorthite phase, in the ash sample.

Abstract: In the present work materials alternative to Ni/YSZ cermets anodes for Solid Oxide Fuel Cells (SOFCs) have been studied in order to overcome the problems related to catalytic deposition of carbon and the limited tolerance to sulphur. Anodes consisting of (La0.75Sr0.25)(Cr0.5Mn0.5)O3-δ (LSCM25) have been investigated with regard to synthesis and processing related problems. Single phase LSCM25 perovskites were synthesized by urea/nitrates gel combustion method and the as prepared powders were used to produce green tapes by tape casting processing. Thick LSCM25 substrates, suitable as anodes in anode supported SOFC fabrication, were successfully obtained by sintering of green LSCM25 laminates.