Mohammad Farooque

Fuel cells-the clean and efficient power generators

Fuel cell generators ranging from subkilowatt portable power units to multimegawatt stationary power plants are emerging to deliver clean and efficient power using a large variety of gaseous and liquid fuels. This new technology is suitable for producing heat and power for residential, commercial, and industrial customers. The fuel cells produce electricity without combustion and use very few moving parts, typically limited to air blowers, and fuel and/or water pumps. Because of high fuel conversion efficiency, combined heat and power generation flexibility, friendly siting characteristics, negligible environmental emissions, and lower carbon dioxide emissions, fuel cells are considered at the top of the desirable technologies for a broad spectrum of power generation applications. This paper discusses different fuel cell technologies, the various applications, and reviews their commercialization considerations and status.

Carbonate Fuel Cell: Principles and Applications

In recent years, carbonate fuel cell technology has enjoyed a steady improvement both in cost reduction and performance. Large-scale manufacturing combined with a multitude of power plant installations has resulted in the establishment of the carbonate fuel cell technology as a leading candidate for efficient and reliable distributed generation.

Development of Direct Carbonate Fuel Cell Systems for Achieving Ultrahigh Efficiency

FuelCell Energy, Inc (FCE) has developed products based on its Direct FuelCell® (DFC® ) technology with efficiencies near 50 percent based on lower heating value of (LHV) of natural gas. DFC is an internally reformed molten carbonate fuel cell (MCFC) which operates in the 550–700 C range. The combination of the internal reforming of methane and atmospheric pressure and moderately high temperature of operation has resulted in very simple power plant system configurations. Recently, FCE has developed system concepts to further increase the net electric efficiency to beyond 60% efficiency in subMW and MW class power plants. One of these system concepts is the arrangement of the fuel cell stacks in series for very high utilization of fuel in the stacks. Although, in principle, the concept of fuel cell stacks in series is very simple, the implementation of the concept in the actual hardware poses challenges requiring innovative solutions. These challenges include concerns with thermo-mechanical issues, flow and utilization patterns within the fuel cell stacks, and management of the pressure balance between the anode-and-cathode. To address, these issues, various analytical tools including system-level modeling and simulation and Computational Fluid Dynamics (CFD) were utilized. FCE has developed a comprehensive fuel cell stack operation simulation model including hydrodynamics, kinetics, electro-chemical, and heat transfer mechanisms to investigate and optimize the design for performance as well as endurance. Various system configurations were developed which included methods for fueling the second tier stacks in the series. System simulation studies using first principle mass and energy conversation laws were performed. Parametric studies were completed. Subsequent to the system modeling results, the fuel cell stacks operations were analyzed using the Comprehensive Stack Simulation model. The CFD modeling of the fuel cell stacks were performed in support of the system simulation parametric studies. The results of the CFD modeling provided insight to the thermal and flow profiles of both first and second tier stacks in series. The net outcome of the investigation was the design of the system which met the goals of ultra high efficiency and yet complied with the thermo-mechanical requirements of the fuel cell stack components. In this paper, FCE will describe various system options for the very high efficiency systems, the issues related to the design, and the practical solutions to overcome the issues.Copyright

Development of Direct Carbonate Fuel Cell Systems for Achieving Ultra High Efficiency

FuelCell Energy, Inc (FCE) has developed products based on its Direct FuelCell® (DFC® ) technology with efficiencies near 50 percent based on lower heating value of (LHV) of natural gas. DFC is an internally reformed molten carbonate fuel cell (MCFC) which operates in the 550–700 C range. The combination of the internal reforming of methane and atmospheric pressure and moderately high temperature of operation has resulted in very simple power plant system configurations. Recently, FCE has developed system concepts to further increase the net electric efficiency to beyond 60% efficiency in subMW and MW class power plants. One of these system concepts is the arrangement of the fuel cell stacks in series for very high utilization of fuel in the stacks. Although, in principle, the concept of fuel cell stacks in series is very simple, the implementation of the concept in the actual hardware poses challenges requiring innovative solutions. These challenges include concerns with thermo-mechanical issues, flow and utilization patterns within the fuel cell stacks, and management of the pressure balance between the anode-and-cathode. To address, these issues, various analytical tools including system-level modeling and simulation and Computational Fluid Dynamics (CFD) were utilized. FCE has developed a comprehensive fuel cell stack operation simulation model including hydrodynamics, kinetics, electro-chemical, and heat transfer mechanisms to investigate and optimize the design for performance as well as endurance. Various system configurations were developed which included methods for fueling the second tier stacks in the series. System simulation studies using first principle mass and energy conversation laws were performed. Parametric studies were completed. Subsequent to the system modeling results, the fuel cell stacks operations were analyzed using the Comprehensive Stack Simulation model. The CFD modeling of the fuel cell stacks were performed in support of the system simulation parametric studies. The results of the CFD modeling provided insight to the thermal and flow profiles of both first and second tier stacks in series. The net outcome of the investigation was the design of the system which met the goals of ultra high efficiency and yet complied with the thermo-mechanical requirements of the fuel cell stack components. In this paper, FCE will describe various system options for the very high efficiency systems, the issues related to the design, and the practical solutions to overcome the issues.Copyright