EM - Escola de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6

Notícias

A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.

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Filtros

2019 - 20202

Configurações

Assunto: search.filters.subject.Hybrid system

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
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    Analysis of a hybrid molten carbonate fuel cell and gas turbine cycle.
    (2020) Leal, Elisângela Martins; Silva, Barbara Emanuelle Sanches; Leal Júnior, Amauri Menezes
    Background: Hybrid systems with fuel cells and thermal engines are studied with promising results. Molten carbonate fuel cells (MCFC) show many advantages compatible with the current demands for energy production in a sustainable competitive way. Materials and Methods: This paper focuses on the computational investigation of an indirect internal reforming MCFC coupled to a gas turbine (GT) system. The technical analysis comprises of energy analysis of the hybrid cycle, using the Gibbs function minimization technique for the methane steam reforming process. The assessment is performed to determine the influence of the hybrid cycle operating temperature and pressure, steam-to-carbon ratio, and fuel and oxidant usage in the fuel cell. Results: Results show that the increase in temperature and in operating pressure of the fuel cell and the fuel reform rate improves the hybrid system performance. Variation in the utilization factor, however, did not determine an expressive increase in system efficiency. For the same fuel mass flow rate, it is possible to see that the variation in the operating temperature of the fuel cell resulted in an increase in the total power of the hybrid system when compared to the results of the pressure increase. The increase in temperature resulted in a maximum increase of 12% in delivered power and corresponding to about 7% system efficiency increase. Instead, an increase in pressure of about 4% corresponding to an increase of about 2% system efficiency. Conclusion: Although an increase in the fuel cell's power density was observed for the same mass flow rate in the system, the pressure negatively influenced the total delivered power by the fuel cell.
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    Technical analysis of a hybrid solid oxide fuel cell/gas turbine cycle.
    (2019) Leal, Elisângela Martins; Bortolaia, Luis Antônio; Leal Júnior, Amauri Menezes
    The relatively high operating temperature of the solid oxide fuel cell allows for a highly efficient conversion to power, internal reforming, and high-quality by-product heat for cogeneration or a bottoming cycle. Besides, high-temperature fuel cells offer a good opportunity for coupling to a gas turbine. Fuel cell systems have demonstrated minimal air pollutant emissions and low greenhouse gas emissions. This paper focuses on the investigation and technical analysis of a direct internal reforming solid oxide fuel cell (DIR-SOFC) and a gas turbine (GT) system. The technical analysis comprises of an energy and exergy analysis of the hybrid cycle, using the Gibbs function minimization technique for the methane steam reforming process. The assessment is performed to determine the influence of the hybrid cycle operating temperature and pressure, steam-to-carbon ratio and fuel and oxidant usage in the fuel cell. Equilibrium calculations are made to find the ranges of inlet steam-to-carbon ratio and the operating current density of the fuel cell. After that, a hybrid system consists of a DIR-SOFC and a GT is evaluated using computer simulation. The results showed that the fuel cell is the main power producer system at the design point. The high-energy efficiency (around 62%) and exergy efficiency (around 58%) are achieved by the hybrid cycle compared to fuel cell efficiency (about 40%) and the GT (around 38%). The power ratio (SOFC/GT) found was 1.50. An analysis varying the fuel cell current density and the GT pressure ratio was performed showing that the fuel cell power production decreases about 7% with increasing current density when the GT becomes the main power-producing equipment. However, the system energy efficiency decreases with the reduction of power produced by the fuel cell.