Fuel alkaline

Electrolyte dissolved fuel alkaline fuel cells, 12 216 Electrolytes AFC, 12 215 aqueous, 9 591-593 batteries, 3 415-418 in continuous saponification, 22 738 defined, 3 409... 

In Germany, sea trials got underway of a submarine powered by a hydrogen-fueled alkaline fuel cell developed by Siemens. 

CO tolerance is one of the primary reasons that higher temperature membranes are sought for PEFCs. For high-temperature molten carbonate and solid oxide fuel cells, no gas cleanup is necessary since the CO can be used as a fuel. Alkaline fuel cells are not suitable for reformed gas since they are intolerant to CO2. 

This type of alkaline fuel cell is easy to fabricate and is used for high power generation. The schematic of a dissolved fuel alkaline fuel cell is shown in Fig. 1.8. 

Alkaline Fuel Cell. The electrolyte ia the alkaline fuel cell is concentrated (85 wt %) KOH ia fuel cells that operate at high (- 250° C) temperature, or less concentrated (35—50 wt %) KOH for lower (<120° C) temperature operation. The electrolyte is retained ia a matrix of asbestos (qv) or other metal oxide, and a wide range of electrocatalysts can be used, eg, Ni, Ag, metal oxides, spiaels, and noble metals. Oxygen reduction kinetics are more rapid ia alkaline electrolytes than ia acid electrolytes, and the use of non-noble metal electrocatalysts ia AFCs is feasible. However, a significant disadvantage of AFCs is that alkaline electrolytes, ie, NaOH, KOH, do not reject CO2. Consequentiy, as of this writing, AFCs are restricted to specialized apphcations where C02-free H2 and O2 are utilized. 

Hydrogen-storage alloys (18,19) are commercially available from several companies in the United States, Japan, and Europe. A commercial use has been developed in rechargeable nickel—metal hydride batteries which are superior to nickel—cadmium batteries by virtue of improved capacity and elimination of the toxic metal cadmium (see BATTERIES, SECONDARYCELLS-ALKALINe). Other uses are expected to develop in nonpolluting internal combustion engines and fuel cells (qv), heat pumps and refrigerators, and electric utility peak-load shaving. 

The lignitic coals of the northern United States tend to have low sulfur contents, making them attractive for boilet fuels to meet sulfur-emission standards. However, low sulfur content coals have impaired the performance of electrostatic precipitators. The ash of these coals tends to be high in alkaline earths (Ca, Mg) and alkaUes (Na, K). As a result, the ash can trap sulfur as sulfites and sulfates (see Airpollution control methods). 

Basic oxides of metals such as Co, Mn, Fe, and Cu catalyze the decomposition of chlorate by lowering the decomposition temperature. Consequendy, less fuel is needed and the reaction continues at a lower temperature. Cobalt metal, which forms the basic oxide in situ, lowers the decomposition of pure sodium chlorate from 478 to 280°C while serving as fuel (6,7). Composition of a cobalt-fueled system, compared with an iron-fueled system, is 90 wt % NaClO, 4 wt % Co, and 6 wt % glass fiber vs 86% NaClO, 4% Fe, 6% glass fiber, and 4% BaO. Initiation of the former is at 270°C, compared to 370°C for the iron-fueled candle. Cobalt hydroxide produces a more pronounced lowering of the decomposition temperature than the metal alone, although the water produced by decomposition of the hydroxide to form the oxide is thought to increase chlorine contaminate levels. Alkaline earths and transition-metal ferrates also have catalytic activity and improve chlorine retention (8). 

Typical polarization curves for alkaline fuel cells are shown in Fig, 27-63, It is apparent that the all aline fuel cell can operate at about 0,9 and 5()() rnA/cnr current density. This corresponds to an energy conversion efficiency of about 60 percent IIII, The space shuttle orbiter powder module consists of three separate units, each measuring 0,35 by 0,38 by I rn (14 by 15 by 40 in), weighing 119 kg (262 lb), and generating 15 kW of powder. The powder density is about 100 W/L and the specific powder, 100 W/kg,... 

Corrosion is described as hot corrosion and sulfidation processes. Hot corrosion is an accelerated oxidation of alloys caused by the deposition of Na2S04. Oxidation results from the ingestion of salts in the engine and sulfur from the combustion of fuel. Sulfidation corrosion is considered a form of hot corrosion in which the residue that contains alkaline sulfates. Corrosion causes deterioration of blade materials and reduces component life. 

Better resistance to many chemicals associated with the automobile industry. This covers not only commonly used automobile fuels, oils and greases, but detergents, alcohols, aliphatic and aromatic hydrocarbons and alkaline chemicals. 

C41 Cyanide Oxidation -- Alkaline Chlorination R09 Reuse as Fuel - Other... 

Leclanche or dry cell Alkaline Cell Silver-Zinc Reuben Cell Zinc-Air Fuel Cell Lithium Iodine Lithium-Sulfur Dioxide Lithium-Thionyl Chloride Lithium-Manganese Dioxide Lithium-Carbon Monofluoride... 

Bacon makes first practical Alkaline fuel cell (5kW) (1959)... 

There are five classes of fuel cells. Like batteries, they differ in the electrolyte, which can be either liquid (alkaline or acidic), polymer film, molten salt, or ceramic. As Table 1 shows, each type has specific advantages and disadvantages that make it suitable for different applications. Ultimately, however, the fuel cells that win the commercialization race will be those that are the most economical. 

---