The growth of particles of lithium aluminate in the electrolyte matrix of molten carbonate fuel cells is problematic in that the particles agglomerate in the electrolyte with the passage of time, thereby decreasing retention of the alkali carbonate melt. To further elucidate the growth mechanism of lithium aluminate particles, the effects of temperature, Pco2, and Li/K ratio in the melt on particle growth were determined. Equilibrium solubility measurements of lithium aluminate in a molten carbonate were also performed under various conditions. The results indicated that particle growth depends on the basicity of the electrolyte.
Using a high purity sapphire plate, the corrosion rate of alumina in molten carbonates was measured with a laser microscope. Results indicate that, when the CO2 partial pressure in the atmospheric gas is low and the operating temperature is high, the corrosion layer increases in thickness in proportion to a two-thirds power with time. As lithium aluminate, the corrosion product, tends to assume a granular shape and corrosion layers are likely to be porous, molten carbonates are believed to readily reach the surface of the alumina. For this reason, this phenomenon deviates from the square root rule which is, in general, applied in evaluating the corrosion of materials. When an alumina plate, blended with silica, is immersed in molten carbonates, part of the silica dissolves into the molten carbonates, thereby increasing the alumina plate surface roughness. The contact area between the alumina and the molten carbonates increased, resulting in increased corrosion.
As the energy consumption has been increasing rapidly in the commercial sector in Japan, the market potential for the micro gas turbine is significant and it will be realized substantially if the thermal efficiency is improved. One of measures is to introduce the steam injection system using the steam generated by the heat recovery steam generator. Steam injection tests have been carried out using a micro gas turbine (Capstone C60). Test results showed that key performance parameters such as power output, thermal efficiency and emissions were improved by the steam injection. The stable operation of micro gas turbine with steam injection was confirmed under various operating conditions. Consequently, a micro gas turbine based co-generation package with steam injection driven by a heat recovery steam generator (HRSG) with supplementary firing is proposed.
Many concerns have been raised concerning the mechanism whereby the thickness of electrodes in molten carbonate fuel cells is reduced over time. We reported in a previous paper that when CO2 partial pressure in the atmospheric gas is low and the temperature of molten carbonates is high, porous nickel oxide deforms easily under compressive stress. In this paper, the mechanism of cathode deformation, which has not yet been clarified, was investigated. Results indicate that cathode deformation occurs when particles in a highly stressed porous nickel oxide dissolve and then reprecipitate to adjacent particles which are less stressed.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 152.14.136.77 Downloaded on 2015-03-17 to IP
Lithiation of Alumina in Molten Li/K Carbonates.-The title process is studied with regard to an improvement of the durability of molten carbonate fuel cells (MCFC). The corrosion rate of a highly pure sapphire plate in molten carbonates is particularly high at high temp. and low CO2 pressure. Porous layers of granular LiAlO2 are formed as corrosion products. Silica, often contained in alumina fibers, partly dissolve in the molten carbonates and hence increase the surface roughness and the corrosion rate. -(MURAI, M.; TAKIZAWA, K.; SOEJIMA, K.; SOTOUCHI, H.; J.
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