Mitsukuni Mizuno

Electrochemical removal of NO in the presence of excess O2, H2O and CO2 using Sm2O3-doped CeO2 as a solid electrolyte

Abstract Electrochemical removal of NO from a gas stream containing 2% O 2 , 5% H 2 O and 5% CO 2 has been carried out between 400 and 800 °C using a single-compartment reactor, constructed from CeO 2 -based solid electrolyte with two palladium electrodes. At all temperatures studied, NO was decomposed to N 2 at the palladium cathode by applying a direct current to the reactor. The dependence of the conversion of NO to N 2 on the concentration of NO, O 2 , H 2 O or CO 2 was investigated at 450 °C in detail.

Ultra-fine grinding of La0.8Sr0.2MnO3 oxide by vibration mill

Abstract The grinding operation of La 0.8 Sn 0.2 MnO 3 (LSM) powder by a vibration mill has been carried out with the intention of giving a higher surface area and a good thermal stability. The specific surface area of the LSM powder increased with operation time and reached up to 34 m 2 g −1 for 350 h. XRD measurement and chemical analysis showed that during the grinding operation, the crystal structure of the LSM powder was kept and that the extent of the contamination was negligibly small. In CH 4 oxidation at 400°C and N 2 O reduction at 450°C over the ground LSM powder, both conversions were raised proportional to the increasing specific surface area. Furthermore, the thermal stability of the ground LSM powder was improved by grinding it together with CeO 2 powder. The fine dispersion of CeO 2 particles around the LSM particles effectively depressed the sintering of the LSM powder at elevated temperatures.

Electrochemical removal of NO and CH4 in the presence of excess O2, H2O and CO2 using Sm2O3-doped CeO2 as a solid electrolyte

Electrochemical removal of NO and CH4 from a gas stream containing excess O2, H2O and CO2 has been carried out between 400 and 800 °C using a single-compartment reactor, which is constructed from CeO2-based solid electrolyte with two palladium electrodes. At all temperatures studied, both NO and CH4 were decomposed by applying a direct current to the reactor. NO was decomposed to N2 in two different ways depending on the applied current. At low currents, NO was electrolysed together with O2 at the palladium cathode; and, at high currents, NO was catalytically reduced over the palladium surface free from adsorbed oxygen. By investigating the influences of the concentration of NO, H2O, CO2, CH4 or C3H8 contained in the reactant gas to these two decompositions, their mechanisms are discussed in detail.

Dependency of tortuosity on capillary suction potentials of compressible and incompressible particulate beds

Measurements of capillary suction potential in drainage processes have developed a capillary bundle model, which makes it reasonably possible to deduce a dimensionless capillary suction potential by considering the dependency of tortuosity. The capillary suction potential has been found to depend strongly on the tortuosity, especially for the compressible filtered cakes. The tortuosity determined empirically using the capillary model provides the dimensionless capillary suction potential which can correlate to the reduced saturation for both incompressible particulate beds and compressible filtered cakes. The final average residual saturation can be accurately estimated from calculation of a newly defined capillary number, which takes into account the final equilibrium saturation profile. The calculated results agree well with experiments observed for incompressible particulate beds drained under gravity.