Environment-friendly energy system

The use of methanol as a medium for transporting hydrogen-based energy offers the possibility of establishing a global system for obtaining and transporting unlimited quantities of sustainable, clean energy. Using various sources of renewable energy (hydroelectric, solar, geothermal, wind), hydrogen can be produced through an efficient electrolytic process. This hydrogen can be combined with CO2 obtained from power plants in various parts of the world to produce methanol, which can then be transported to areas with high energy consumption for use as fuel in power plants. However, the cost of the methanol synthesized from hydrogen and CO2 will be nearly four times as high as that of the present commercial methanol. The authors examined a method for the production of methanol or dimethyl ether by a solar thermochemical process using concentrated solar energy. The concentrated solar thermal energy is absorbed by methane reforming and coal gasification, both of which are endothermic reactions that produce carbon monoxide and hydrogen. Th ese gases are then consumed to produce methanol or dimethyl ether. The authors evaluated the amount of CO2 emission when the methanol or di methyl ether was used and the cost of the methanol produced by this process. The amount of CO2 emission using hybridized dimethyl ether (methanol) was estimated to be 60 to 80 % of the amount emitted using coal or natural gas. The cost of the hybridised methanol was estimated to be 2.45/kWh, which is about 20 % of the cost of the liquid hydrogen produced using renewable energy. A preliminary analysis of zero-emission power plants indicated the possibility of achieving 60% gross thermal efficiency (HHV).

Mechanism of Biological Fe3O4 Synthesis, in Relation to Ferrite Plating

The mechanism of the magnetosome (Fe3O4) formations is elucidated from the basic findings on chemical reactions of iron oxides, especially those occurring in ferrite plating-a chemical process synthesizing spinel ferrite films from an aqueous solution. It is suggested that in both the biomineralization and the ferrite plating, (1) Fe2+ → Fe3+ oxidation by NaNO2 plays an essential role, (2) γ-FeOOH is formed as a precursor, and (3) Fe2+ ions are adsorbed on γ-FeOOH which is followed by spinel formation. It is also discussed how to synthesize ferrite films at room temperature by mimicking the biological Fe3O4 formation

H2 Evolution Reactivity of Carbon-Bearing Ni(II) Ferrite (CBNF)

Two-step water-splitting with a carbon-bearing Ni(II) ferrite (CBNF) at 300°C has been studied. The chemical analysis of the solid phase showed that the CBNF was gradually oxidized during repeated water splitting, but the evolved H2 amount is 1.5-2 times larger than that expected from the oxidation of the CBNF. Following two types of hydrogen evolution reactions are considered to be participated : Type I is the water splitting by the activated form of CIO layer(αn), where the activated form changes to the original form (βn), Type II is hydrogen evolution by the oxidation of CIO layer, where the original CIO layer form(βn) changes to an oxidized form (βn+1). The amount of released oxygen was about 40-80% of the amount estimated from the amount of hydrogen gas evolved by the Type I reaction. Thus, the stoichiometry of the above two steps has been demonstrated