Carbonates, molten

Fuels which have been used include hydrogen, hydrazine, methanol and ammonia, while oxidants are usually oxygen or air. Electrolytes comprise alkali solutions, molten carbonates, solid oxides, ion-exchange resins, etc. 

AFC = all line fuel ceU MCFC = molten carbonate fuel ceU PAFC = phosphoric acid fuel ceU PEFC = polymer electrolyte fuel ceU and SOFC = solid oxide fuel ceU. 

In low temperature fuel ceUs, ie, AEG, PAEC, PEEC, protons or hydroxyl ions are the principal charge carriers in the electrolyte, whereas in the high temperature fuel ceUs, ie, MCEC, SOEC, carbonate and oxide ions ate the charge carriers in the molten carbonate and soHd oxide electrolytes, respectively. Euel ceUs that use zitconia-based soHd oxide electrolytes must operate at about 1000°C because the transport rate of oxygen ions in the soHd oxide is adequate for practical appHcations only at such high temperatures. Another option is to use extremely thin soHd oxide electrolytes to minimize the ohmic losses. 

Molten Carbonate Fuel Cell. The electrolyte ia the MCFC is usually a combiaation of alkah (Li, Na, K) carbonates retaiaed ia a ceramic matrix of LiA102 particles. The fuel cell operates at 600 to 700°C where the alkah carbonates form a highly conductive molten salt and carbonate ions provide ionic conduction. At the operating temperatures ia MCFCs, Ni-based materials containing chromium (anode) and nickel oxide (cathode) can function as electrode materials, and noble metals are not required. 

S. Sato, in J. R. Sehnan and co-workers, eds.. Proceedings of the Second Symposium on Molten Carbonate Fuel CellTechnology, The Electrochemical Society, Inc., Pennington, N.J., 1990, p. 137. 

Hydrogen use as a fuel in fuel cell appHcations is expected to increase. Fuel cells (qv) are devices which convert the chemical energy of a fuel and oxidant directiy into d-c electrical energy on a continuous basis, potentially approaching 100% efficiency. Large-scale (11 MW) phosphoric acid fuel cells have been commercially available since 1985 (276). Molten carbonate fuel cells (MCFCs) ate expected to be commercially available in the mid-1990s (277). 

An emerging electrochemical appHcation of lithium compounds is in molten carbonate fuel ceUs (qv) for high efficiency, low poUuting electrical power generation. The electrolyte for these fuel ceUs is a potassium carbonate—hthium carbonate eutectic contained within a lithium aluminate matrix. The cathode is a Hthiated metal oxide such as lithium nickel oxide. 

The molten carbonate fuel ceU uses eutectic blends of Hthium and potassium carbonates as the electrolyte. A special grade of Hthium carbonate is used in treatment of affective mental (mood) disorders, including clinical depression and bipolar disorders. Lithium has also been evaluated in treatment of schizophrenia, schizoaffective disorders, alcoholism, and periodic aggressive behavior (56). 

Static Pressure Synthesis. Diamond can form direcdy from graphite at pressures of about 13 GPa (130 kbar) and higher at temperatures of about 3300—4300 K (7). No catalyst is needed. The transformation is carried out in a static high pressure apparatus in which the sample is heated by the discharge current from a capacitor. Diamond forms in a few milliseconds and is recovered in the form of polycrystalline lumps. From this work, and studies of graphite vaporization/melting, the triple point of diamond, graphite, and molten carbon is estimated to He at 13 GPa and 5000 K (Fig. 1)... 

Molten Carbonate Fuel Cell The electrolyte in the MCFC is a... 

Molten Carbonate Fuel Cell developed by Baur (1921)... 

Molten Carbonate -650 Some fuel flexibility High-grade waste heat Fragile electrolyte matrix Electrode sintering Distribute power Utilities... 

The PAFC is, however, suitable for stationary power generation, but faces several direct fuel cell competitors. One is the molten carbonate fuel cell (MCFC), which operates at "650°C and uses an electrolyte made from molten potassium and lithium carbonate salts. Fligh-teinperature operation is ideal for stationary applications because the waste heat can enable co-generation it also allows fossil fuels to be reformed directly within the cells, and this reduces system size and complexity. Systems providing up to 2 MW have been demonstrated. 

As the name suggests these cells use an electrol5de of molten carbonates (generally of lithium and potassium) and in order to keep the carbonates molten and provide good conductivity the cells need to operate at around 650 °C. This type of cell is becoming increasingly favoured for commercial power production. The moderate operating temperature means that... 

Destruction of chlorinated organic solvents in a molten carbonate with transition metal oxides... 

The Surface Fractal Investigatioii of Anode Electrode of Molten Carbonate Fuel Cell... 

In order to describe the geometrical and structural properties of several anode electrodes of the molten carbonate fuel cell (MCFC), a fractal analysis has been applied. Four kinds of the anode electrodes, such as Ni, Ni-Cr (lOwt.%), Ni-NiaAl (7wt.%), Ni-Cr (5wt.%)-NijAl(5wt.%) were prepared [1,2] and their fractal dimensions were evaluated by nitrogen adsorption (fractal FHH equation) and mercury porosimetry. These methods of fractal analysis and the resulting values are discussed and compared with other characteristic methods and the performances as anode of MCFC. 

W. He and Kas Hemmes, Operating characteristics of a reformer for molten carbonate fuel-cell power-generation systems. Fuel Processing Technology, 67 (2000) 61. 

Molten Carbonate 923 K and Solid Oxide Fuel Cells, 1273 K... 

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