Fuel Cells for Power Generation

Since thin layers of materials are a necessary part of most fuel cell construction, tape casting has been used extensively in this field. There are two basic types of fuel cells solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC). 

4 m (4 X 8 ft.) are projected for manufacture during that time frame. This is amazing, considering the fact that the thickness of these tapes is on the order of 0.5 mm (0.020 in.)  

An interesting application of an old process invented by one of the authors has been reviewed recently by Japanese authors at the Matsushita Electric Industrial Co., Ltd. In their paper they describe a process for fabrication of the electrode and electrolyte at the same time, using a multiple casting technique in which one layer is cast on top of the other. The authors claim a simplified manufacturing process as well as better contact between the electrodes and the electrolyte. Once again, the use of tape casting was an important aspect of the processing. 

A considerable amount of research is being conducted to produce functionally gradient materials (FGMs) for a wide variety of applications. The ability to tape-cast and laminate several layers of materials with differing chemical compositions makes these FGMs possible. We will describe a few of these that have appeared in the literature and will add some speculative ideas of our own. 

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Proton exchange membrane fuel cells (PEMFCs) work with a polymer electrolyte in the form of a thin, permeable sheet. The PEMFCs, otherwise known as polymer electrolyte fuel cells (PEFC), are of particular importance for the use in mobile and small/medium-sized stationary applications (Pehnt, 2001). The PEM fuel cells are considered to be the most promising fuel cell for power generation (Kazim, 2000). 

SOFC. One SOFC project is to open up for offshore production of oil and gas without COj emissions to the atmosphere. Another activity is concentrated on improving the working efficiency and competitiveness of SOFC fuel cells for power generation with natural gas. The third R D activity on SOFC is related to filter mechanisms for cleaning hydrogen from gasified biomass to reach sufficient purity for use in an SOFC. 

The amount of hydrogen utilised in specific processes of energy conversion and application will increase. For example, such occasions will increase as the case of stationary fuel cell, in which hydrogen is produced by the steam reforming of natural gas, kerosene or petroleum gas, and immediately consumed in a fuel cell for power generation. 

General Electric Co. Development of Molten Carbonate Fuel Cells for Power Generation, Report No. SRD 80-053 General Electric Co. Apr 1980. 

On May 6,2002 the Public Utility Commission of Texas published for public comment a Staff White Paper on Stationary Fuel Cells for Power Generation www.seco.cpa.state.tx.us /fciac pucpaper.pdf. This paper presented a discussion on the attractiveness of fuel cell systems for the state, described the obstacles to state development of a fuel cell program, presented a roadmap for the establishment of a vibrant fuel cell industry in Texas, and offered an outline of legislation that would provide incentives for fuel cell development. This report envisions an installed fuel cell capacity of 1,000 MW in Texas by the year 2010. 

Figure 10.8. Schematic of a fuel cell for power generation (left) and its opposite, a reactor component for gas electrolysis (right). All components are solid the electrolyte is a nonporous, gas-impermeable oxide ion conductor (stabilized zirconia), and the electrodes are porous electron conductors (oxides and cermets).

Solid Oxide Fuel Cells for Power Generation... 

A common group of catalysts are the platinum-group metals which have become essential factors in many industrial processes such as gas-phase oxidation, selective hydrogenation of petrochemical and pharmaceutical feedstocks, fuel cells for power generation, and many others. Other common catalysts are iron, nickel, and some transition metals. 

Ni M, Leung M K H, Leung D Y C, Ammonia-fed solid oxide fuel cells for power generation - A review , International Journal of Energy Research, 2009, 33, 943-959. 

S. You, Q. Zhao, J. Zhang, J. Jiang, C. Wan, M. Du and S. Zhao, A graphite-granule membrane-less tubular air-cathode microbial fuel cell for power generation under continuously operational conditions, /. Power Sources 173, 2007, 172-177. 

The potential of stationary fuel cells for distributed generation depends on feed-in tariff policies and electricity and gas prices, as well as on market competition from gas engines and small turbines. SOFCs and MCFCs, mostly fuelled by natural gas, are likely to play an important role for combined heat and power generation in buildings. 

Transportation fuel cells are being designed for about 4,000 hours of use, which gives a car a 10-year lifetime since they are used only a small percentage of the time. But 4,000 hours represents less than half a year under continuous use for generating electricity. Fuel cells for power plants are designed for 40,000 hours or more. 

High temperature cells with solid electrolytes of zirconium dioxide have been investigated for the electrolysis of H2O vapor and as fuel cells for the generation of electric power. Examples include the combustion of synthesis gas (CO-H2 mixtures) in cells at temperatures of 1300 K. 

Hydrogen for use in residential fuel cells can be produced from pipeline natural gas using a fuel processor. Assume that a residential, fuel-cell, electric-power generator with 5 kW electricity output has an efficiency of 50% (the electricity output from the fuel cell is 50% of the lower... 

Fuel cells are power generation devices converting chemical energy into electric energy by electrochemical reactions. A typical fuel cell is comprised of two electrodes separated by an electrolyte, with a provision of reactant supply and product removal. Among various types of fuel cells, Ha-O -based polymer electrolyte membrane (PEM) fuel cells (PEMFC) have attracted special attention due to their high efficiency, low temperature operation and suitability for low to medium power generation. Basic components of a PEMFC are PEM, catalyst layer, gas diffusion layer and... 

Shi Z, Luo J-L, Wang S, Sanger A R and Chuang K T (2008), Protonic membrane for fuel cell for co-generation of power and ethylene , / Power Sources, 176, 122-127. 

Hefner, A. (2007) Power electronics for fuel cell based power generation systems, in Proceedings of 8th SECA Annual Workshop, FUEL CELL 2005-74176, US Department of Energy, National Energy Technology Laboratory, Morgantown, WV. 

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