Showing papers by "Umberto Desideri published in 2003"

State of the Art About the Effects of Impurities on MCFCs and Pointing Out of Additional Research for Alternative Fuel Utilization

Abstract: Fuel cells are very flexible energy conversion devices and in particular MCFC power generating system are among the most promising for stationary power generation. Potentially, MCFCs can be fed by a great variety of gaseous fuels comprising low calorific values gases like landfill gas. Thanks to fuel processing technologies, like gasification, suitable anode input gases can also be obtained from solid matters. Coal, but also RDF (Refuse Derived Fuel), industrial waste and biomasses are potential fuels for the fuel cell technology after a specific treatment aimed to yield a proper gas for the cell requirements. The gases mentioned above are characterized by low calorific values, presence of inert gases, presence of carbon monoxide and dioxide, presence of various contaminants such as chlorine, sulphur and nitrogen compounds or metals and they can be utilized for power production in high temperature fuel cell units only after a proper clean-up treatment (tars, particulate and sulphur removal). Although interest in alternative fuels for fuel cells has spread in the recent years, most research activity related to fuel treatment has been performed on methane. The biggest drawback deriving from this situation is a general lack of information. When present, moreover, the information is often contradictory. An example of this is given by the acceptable contaminants levels for molten carbonate fuel cells about which there are not values that are based on sufficient experimental evidence. Unfortunately the design of a clean-up system, the choice of the best technology, the optimization of the BOP relies just on these values. In this work a literature research and an analysis of the present knowledge about the effect of impurities in fuel for fuel cells has been preformed. The goal is the definition of concentration levels that can be tolerated by MCFCs and the degradation in performance or the reduction of cell life related to the presence of different pollutants. A second step of the work is the comparison of the levels of impurities tolerated by the cells with those present in the different low calorific value gases in order to define the clean-up requirements. The research priorities in this field have been pointed out. Finally, the project of the fuel cell team of University of Perugia about this topic is briefly described.Copyright © 2003 by ASME

IPRP: Integrated Pyrolysis Combined Plant — An Efficient and Scalable Concept for Gas Turbine Based Energy Conversion From Biomass and Waste

Abstract: A massive effort towards sustainability is necessary to prevent global warming and energy sources impoverishment: both biomass and waste to energy conversion may represent key actions to reach this goal. At the present State Of the Art (SOA) available technologies for biomass and waste to energy conversion are similar and include low to mid efficiency grate incineration or fluidised bed combustion with steam power cycles or mid to high efficiency Gas Turbine based cycles through integrated gasification technology. Nevertheless these plants are all available from mid-to-high scale range that can be highly intrusive on protected areas and socially unacceptable. This paper proposes an innovative, low cost, high efficiency plant in which the residue is gasified in absence of oxygen (pyrolysis), in a rotary kiln, by means of a highly regenerative gas turbine based cycle. Pyrolysis is preferred to gasification, because the syngas obtained has a higher LHV and produces char or tar as a by-product with an interesting energy content to be re-utilized inside the cycle. Different plant configurations are proposed and discussed through principal thermodynamic variables parametric analysis. Results show that very interesting efficiencies are obtainable in the 30%–40% range, at every scale range therefore presenting an interesting alternative especially to small size (below 5 MW) grate incineration and steam power plant technology. Moreover, the IPRP plant provides a unique solution for micro-scale (below 500 kW) power plants, opening a new and competitive possibility for distributed biomass or waste to energy conversion systems where low environmental and social impact turns into higher interest and positive dissemination effect.Copyright © 2003 by ASME

Perspectives on the Use of Molten Carbonate Fuel Cells with Renewable Energy Sources

Abstract: This paper presents the state of the art and the perspectives of the use of molten carbonate fuel cells with renewable energy sources. The molten carbonate fuel cell is the only technology that can use fuels containing carbon monoxide and carbon dioxide in the anode gas. It has been even shown in experimental tests in single cells that carbon monoxide can be considered as a fuel in this type of fuel cell. The fuels that can be used in MCFC are landfill gas, biogas from anaerobic digestion processes and syngas from gasification of biomass and waste. The commercial size of MCFC stacks (125 to 250 kW) is the right size for use with such fuels which are generally not available for power plants with output larger than some MW. All the above fuels are characterized by the presence of contaminants that need be removed before their use in the fuel cell. Among the contaminants hydrogen sulfide and chlorine compounds seem to cause the worst damage. To be used with such fuels, MCFC still need to be deeply investigated and duration tests are needed to determine the highest tolerable concentrations in the anode gases.Copyright © 2003 by ASME