The main object of this study is to investigate the collection characteristics of wet-type rotating porous disk system experimentally. The experiment is carried out to analyze the pressure drop and collection efficiency for the present system with the experimental parameters such as system inlet velocity, stage number, tube diameter, inlet concentration, etc. In results, for the present system, at 5 stage and υin=1.8 m/s, the pressure drop becomes significantly lower as 64 mmH2O in comparison with that of the conventional wet type scrubber (Venturi scrubber, over 250 mmH2O). The collection efficiencies increase with higher inlet velocity showing 92, 95.7, 98.4%, while SO2 removal efficiencies decrease with increment of inlet velocity as 80, 65, 50% at υin=1.08, 1.44, 1.8 m/s and tube diameter Dt=10 mm, respectively. The present system is to be considered as an effective compact system for a simultaneous removal of particle/gas phase pollutants from marine diesel engines.

이 연구에서는 전 유동장의 순간속도를 계측 할 수 있는 PIV계측기법을 슬라이딩 밸브의 폐쇄 직후에 적용하고 짧은 시간에 발생하는 디스크 주위의 비정상 속도를 계측하여 유동특성을 실험적으로 고찰하였다. 순간유동장을 분석한 결과를 기존의 압력변동을 측정한 연구 결과에 비교 검토한 결과 슬라이드 밸브 급폐쇄에 따른 속도변동이 크게 나타나는 시간구간은 0.1초 이내이고 주기는 0.12초로 추정되었다. 또한 원관 내부의 디스크 주위유동은 상부부터 폐쇄되면서 유로가 좁아져 순간적으로 빠르게 하류로 진행하였으며 폐쇄직후에 역류하는 속도의 크기는 4/120초까지 감소하다가 다시 증가하는 경향을 보였다. 그리고 완전 폐쇄 후 상류 측으로 역류하는 흐름의 영향으로 y/D=0.2 하부 영역에 역류하는 속도성분이 나타났으며, y/D=0.7, x/D=-0.3의 근방에서 0.2D 크기의 회전와류가 관찰되었다.

The catalytic activity of Ni-0.2%YSZ (Yttria-Stabilized Zirconia) with different promoters was evaluated for CO2 methanation. The catalysts were weighed for mixing and they were dried at 110 for molding into disks. The concentration of CO2 and CH4 for conducting of CO2 methanation were analyzed by gas chromatography and the physical characteristics of the disk-type catalyst formed were analyzed by X-ray diffraction, scanning electron microscope and energy dispersive x-ray spectrometer. The addition of CeO2 as a promoter for Ni-0.2%YSZ (denoted as Ni-5%Ce-0.2%YSZ) resulted in the highest CO2 methanation. It also showed catalytic activity at a low temperature(200°C). Following this, ZrO2, SiO2, Al2O3 and TiO2 were added to Ni-5%Ce-0.2%YSZ to compare the CO2 methanation, and the highest efficiency was found for. Ni-1%Ti-5%Ce -0.2%YSZ Then, the concentration of Ti was increased to 10% and the catalytic activity was estimated using seven different types of commercial TiO2. In conclusion, ST-01 TiO2 showed the highest efficiency for CO2 methanation.

A space plasma facility has been operated with a back-diffusion-type plasma source installed in a mid-sized vacuum chamber with a diameter of ~1.5 m located in Satellite Technology Research Center (SaTReC), Korea Advanced Institute of Science and Technology (KAIST). To generate plasma with a temperature and density similar to the ionospheric plasma, nickel wires coated with carbonate solution were used as filaments that emit thermal electrons, and the accelerated thermal electrons emitted from the heated wires collide with the neutral gas to form plasma inside the chamber. By using a disk-type Langmuir probe installed inside the vacuum chamber, the generation of plasma similar to the space environment was validated. The characteristics of the plasma according to the grid and plate anode voltages were investigated. The grid voltage of the plasma source is realized as a suitable parameter for manipulating the electron density, while the plate voltage is suitable for adjusting the electron temperature. A simple physical model based on the collision cross-section of electron impact on nitrogen molecule was established to explain the plasma generation mechanism.

T-N and T-P in the filtrate from Sludge Treatment Process (STP) was returned to water treatment processing, because T-N and T-P are returned, it makes overload in Advanced Treatment Process. Removal efficiency of T-N and T-P are compared both at using polymer as simple method and at using PFS and polymer as complex method when coagulants was injected in Thickener. In simple method, removal efficiency of T-N and T-P were 95.68% and 99.29% for each. In complex method, removal efficiency of T-N and T-P were 98.07% and 99.90% for each. From the result, removal efficiency of complex method was highly better than simple method. According to increasing of removal efficiency, returned T-N and T-P loading to water treatment process was decreased (Reduced amount of T-N is 0.2309 kg/hr and TP is 0.0145 kg/hr). Also, the amount of a polymer used has been decreased to 80% by using PFS.