• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.160-163
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• 2001

In order to develop a nodule conveying system through a flexible pipe out of the deep-seabed manganese nodule miner, an experimental study of the solid-water slurry flow in vertical pipe is performed as the first stage of total experiments. Hydraulic characteristics of the pipe slurry flow such as slip velocity, transport concentration and pressure gradient are investigated for the size of particle, load ratio, and flow rate of water. The higher the load ratio is, the larger the transport concentration and pressure gradient become. The bigger the size of particles is, the larger the pressure gradient becomes. The effectiveness of the flow rate to hydraulic performance is also investigated. This results are to be used for designing crusher and pump, and operating the conveying device.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.