Showing papers by "Shinji Nagata published in 1963"

Interfacial Area in Liquid-Liquid Agitation Systems

Abstract: The interfacial area and the size distribution of the dispersed droplets in liquid-liquid agitation systems are directly measured by photographs with a series of geometrically similar Rushton type standard turbine agitators. Physical properties of the liquids are varied as widely as possible. The effects of the various factors on, interfacial area are investigated and the observed data are correlated by a dimensionless equation. As the interfacial tension decreases, the interfacial area itself increases, while the effect of increases in. agitator speed decreases with the breaking up of the dispersed phase. This is due to the facts that a limitation in drop size appears during ordinary agitation performance and that the size distribution curves transform from Normal to Log-normal ones as the agitator speed increases. So in a system of low interfacial tension the diameter of the greater part of the droplets approaches the minimum limit. The authors introduced a factor which shows the amount of decrease in interfacial area caused by the effect of limitation of the droplet size on the increase in agitator speed. The use of baffle plates for heavy liquid dispersion increases the interfacial area by several times and the baffles become more effective as the difference in densities between the dispersed and the continuous phase increases.

Kinetics of the Hydrogenation of Benzene on a Nickel Catalyst supported on Kieselguhr

Abstract: The kinetics of the catalytic hydrogenation of benzene on a commercial nickel catalyst (dp=2.65mm) was studied by a differential type of flow reactor.The conversion of benzene is 5-8% for ordinary runs, and the maximum deviation of the catalyst temperature in the bed is less than 8°C.Initial rates of reaction without cyclohexane and the rate for reactants containing some cyclohexane were measured at atmospheric pressure over the following range of conditions.Temperature: 140, 160, 180, 200 and 220 [°C]Partial pressure: pH=0.4-0.9, pB=0.1-0.6 pO=0-0.5 [atm.]Flow rate: 26-31 [gr/cm2hr.]Twelve different mechanisms were presented, and checked by comparing experimental data of initial rates with the characteristic curve of the modified rate equationAs a result, the most plausible rate-controlling step was found to be in the surface reaction between one adsorbed benzene molecule and three adsorbed hydrogen molecules on the same type of active sites.The final equation recommended for the vapor-phase hydrogenation of benzene on a nickel catalyst is as follows;