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This paper investigates the performance of a new power cycle, a so called Evaporative Biomass Air Turbine (EvGT-BAT) cycle with gasification for topping combustion. The process integrates an externally fired gas turbine (EFGT), an evaporative gas turbine (EvGT) and biomass gasification. Through such integration, the system may provide the potential for adapting features from different advanced solid-fuel based power generation technologies, e.g. externally fired gas turbine, integrated gasification combined cycle (IGCC) and fluidized bed combustion, thus improving the system performance and reducing the technical difficulties. In the paper, the features of the EvGT-BAT cycle have been addressed. The thermal efficiencies for different integrations of the gasification for topping combustion and the heat recovery have been analyzed. By drying the biomass feedstock, the thermal efficiency of the EvGT-BAT cycle can be increased by more than 3 percentage points. The impact of the outlet air temperature of the high temperature heat exchanger has also been studied in the present system. Finally, the size of the gasifier for topping combustion has been compared with the one in IGCC, which illustrates that the gasifier of the studied system can be much smaller compared to IGCC. The results of the study will be useful for the future engineering development of advanced solid fuel power generation technologies.

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SUMMARYIn this review article the analysis of the main problems related to the use of NiO as material for cathodes in Molten Carbonate Fuel Cells (MCFC) is reported. Thus, the most significant evidences of the mechanism of NiO dissolution have been reported as well as its correlation with the basicity of the carbonate melt, composition of the reactants gases and temperature. Some hypotheses described here have been also verified experimentally and the results of this validation are reported. In the final section, we have described the most promising alternative solutions to this problem and the advantages and shortcomings of these alternatives.1998 John Wiley & Sons, Ltd.

SUMMARYInvestigations have been carried out to study the influence of low operating temperature (873 K) on the decay mechanisms that affect the endurance of a molten carbonate fuel cell. An experiment has been performed for several thousands of hours of continuous operation at a current density of 160 mA cm\ on a bench-scale cell to evaluate the electrochemical performance parameters and morphological characteristics of spent components. The tested components were a traditional LiAlO matrix, charged by a mixture of Li/K, NiO cathode and Ni/Cr anode. During the test, measurements of temperature, pressure, flows, cell internal resistance, current and voltage have been taken continuously, as well as gas chromatography analyses. At the end of the experiment, the cell showed an increase in internal resistance of 0·376 cm\ and a lowering of open-circuit voltage of 30 mV. The electrolyte distribution in the components indicated an excess of empty pores in the tile structure with a filling degree of 72·8%. By contrast, the anode retained a filling degree of 64·3%, while the cathode appeared under partial flooding condition with a filling degree of 48·2%. The SEM cross-section view of the cell package (cathode, tile and anode) showed evidence of a process of cathode dissolution and coprecipitation of Ni in a narrow band located almost in the middle of the section. The Ni, Cr, Al and K distribution profiles in the cross-section were investigated by EDAX analysis.