Direct methanation fuel cells

Murray EP, Tsai T, Barnett SA (1999) A direct-methane fuel cell with a ceria-based anode. Nature 400 649-651... 

E. Perry Murray, T. Tsai, and S.A. Barnett. A Direct-Methane Fuel Cell with a Ceria-Based Anode. Nature, 400 651-659,1999. 

As a second example, consider the direct methane fuel cell overall reaction ... 

Fig. 1.52 Comparison of fuel cell efficiency as a function of trimethoxy-methane concentration (0.25 M, 0.5 M, and 1.0 M solutions) compared with methanol (1.0 M) in liquid-feed direct oxidation fuel cells.

The direct carbonate fuel cell is a variant of molten carbonate fuel cells (MCFC) in that it internally reforms methane-containing fuels within the anode compartment of the fuel cell (Matsumoto et al., 1990 Farooque, 1991 Sasaki et al., 1993 Shinoki et al., 1995). The largest demonstration of MCFC technology has been California s 2-MW Santa Clara Demonstration Project (Fuel Cell Engineering Corporation, 1997). 

Hemmes, K., Houwing, M., and Woudstra, N. (2010) Modeling of a methane fuelled direct carbon fuel cell system./. Fuel Cell Sci. Technol, 7 (6), 061008 / 1-061008/6. 

The search for sorbents for methane storage remains to be an active research area worldwide. Methane storage could play a key role in fuel ceU technology if an effective catalyst is developed for direct methane fuel ceU (i.e., methane is fed directly to the fuel cell). 

It is important to monitor the concentration of methane using a sensor as the fuel crossover may occur. The problem of fuel crossover is severe for the PEM direct methanol fuel cell. Methanol dissolves quickly in water and reaches the cathode. The presence of platinum catalyst on the cathode will oxidise the fuel, though not as effectively as the anode catalysts. Hence, fuel wastage will occur at the cathode reducing the cell voltage. This phenomenon yields mixed potential and the fuel utilisation coefficient //f is defined as... 

Direct Methane Conversion, Methanol Fuel Cell, and Chemical Recycling of Carbon Dioxide... 

A few chemicals are based on the direct reaction of methane with other reagents. These are carbon disulfide, hydrogen cyanide chloromethanes, and synthesis gas mixture. Currently, a redox fuel cell based on methane is being developed. ... 

This reaction is of great technological interest in the area of solid oxide fuel cells (SOFC) since it is catalyzed by the Ni surface of the Ni-stabilized Zr02 cermet used as the anode material in power-producing SOFC units.60,61 The ability of SOFC units to reform methane "internally", i.e. in the anode compartment, permits the direct use of methane or natural gas as the fuel, without a separate external reformer, and thus constitutes a significant advantage of SOFC in relation to low temperature fuel cells. 

In principle biomass is a useful fuel for fuel cells many of the technologies discussed above for using biomass as a fuel produce either methane or hydrogen directly and as highlighted below synthesis gas production from biomass for conversion to methanol is an attractive option. Cellulose-based material may be converted to a mixture of hydrogen (70% hydrogen content recovered), CO2 and methane by high-temperature treatment with a nickel catalyst. 

In the phosphoric acid fuel cell as currently practiced, a premium (hydrogen rich) hydrocarbon (e.g. methane) fuel is steam reformed to produce a hydrogen feedstock to the cell stack for direct (electrochemical) conversion to electrical energy. At the fuel electrode, hydrogen ionization is accomplished by use of a catalytic material (e.g. Pt, Pd, or Ru) to form solvated protons. 

Putna ES, Stubenrauch J, Vohs JM, and Gorte RJ. Ceria-based anodes for the direct oxidation of methane in solid oxide fuel cells. Langmuir 1995 11 4832-4837. 

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