• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.150-159
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• 2018

The present research deals with a finite element analysis and fatigue evaluation of a steam separator of a high-pressure evaporator for the Heat Recovery Steam Generator (HRSG). The fatigue during the expected life of the HRSG was evaluated according to the ASME Boiler and Pressure Vessel Code Section VIII Division 2 (ASME Code). First, based on the eight transient operating conditions prescribed for the HRSG, temperature distribution of the steam separator was analyzed by a transient thermal analysis. Results of the thermal analysis were used as a thermal load for the structural analysis and used to determine the mean cycle temperature. Next, a structural analysis for the transient conditions was carried out with the thermal load, steam pressure, and nozzle load. The maximum stress location was found to be the riser nozzle bore, and hence fatigue was evaluated at that location, as per ASME Code. As a result, the cumulative usage factor was calculated as 0.00072 (much less than 1). In conclusion, the steam separator was found to be safe from fatigue failure during the expected life.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.23-31
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• 2018

Stress of a steam separator, equipment of the high-pressure (HP) evaporator for a HRSG, was analyzed and evaluated according to ASME Boiler & Pressure Vessel Code Section VIII Division 2. First, from the analysis results of the piping system model of the HP evaporator, reaction forces of the riser tubes connected to the steam separator, i.e., nozzle loads, were derived. Next, a finite element model of the steam separator was constructed and analyzed for the design pressure and the nozzle loads. The results show that the maximum stress occurred at the bore of the riser nozzle. The primary membrane stresses at the shell and nozzle were found to be less than the allowable stress. Next, the steam separator was analyzed for the steady-state operating conditions of operating pressure, operating temperature, and nozzle loads. The maximum stress occurred at the bore of the riser nozzle. The primary plus secondary membrane plus bending stress at the shell and nozzle was found to be less than the allowable stress.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.21-31
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• 2000

Performance characteristics of a wet air cleaning system were investigated experimentally, and discussed in relation with physicochemical properties of the target pollutants. The system is composed of an air cleaner, a separator, and a medium filter. Removal efficiency of the system was measured for ambient particles and gaseous air pollutants: $SO_2$, NO, $NO_2$, HCHO, and $NH_3$. For particle removal test, particles were introduced into the system through a fan, and the particle size distribution was measured at three locations by using two laser particle counters. Particle removal efficiency for each system component was obtained from the particle size distribution. It was found that the separator primarily removed coarse particles greater than $5{\mu}m$ in diameter, and that the medium filter mainly removed fine particles less than $5{\mu}m$ in diameter. For gas removal test, air with gaseous air pollutant was injected into the outlet of the fan, and the concentration was measured both at the upstream of the air cleaner and at the downstream of the separator. It was found that the gaseous species with high Henry's law coefficients, such as $SO_2$, HCHO, and $NH_3$, showed high removal efficiency, but the gaseous species with low Henry's law coefficients, such as NO and $NO_2$, showed low removal efficiencies. It was also found that negative ions were generated from the air cleaner.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.112-114
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• 1998

막분리기술은 분릿대상 성분과 분리매체와의 분자 사이의 힘의 차를 이용하여 분리하는 기술이기 때문에 분리특성을 고도로 기능화시키는 것이 가능하다. 또한 막분리 기술 자체가 에너지 절약기술이기 때문에 차세대 분리기수로서 중요한 역할을 할 수 있다. 이와 같은 분리기술은 역삼투법 등의 수용액계와 상온 부근의 기체분리막은 실용화되어 있다. 그러나 비수용액계 또는 고온 공정에서 특수한 조건하에서 고기능성 분리성능을 가지는 막의 개발에 대한 요구가 증대되고 있다. 이에 대응하여 내열성, 내용제성이 우수한 고분자에 의한 분리성능을 요구한다. 특히 근년에는 방향족 polyimide 수지가 주목을 받고 있으며, 내열성, 내구성 및 기계-전기적 특성이 우수한 재질로 광범위하게 사용되고 있다. 이것은 분자 구성기가 가지는 결합에너지가 크고, 분자의 규칙성에 의한 유리전이온도가 높아서 250-300$\circ$C의 고온에서도 사용이 가능한 재료로서 한외여과막과 기체분리막으로 시판되고 있다.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.403-404
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• 2008

자원의 고갈과 각종 환경규제 및 정부의 전력거래 방침 등으로 인해 점점 발전소에서는 전력 계통에 대한 신뢰도 및 전기품질을 유지하기가 어려워지고있다. 발전소의 부하대별 주요 운전 설계값은 효율과 바로 직결되는 사항으로 각 부하별로 온도와 압력 등 운전설계값을 최적의 상태로 유지하는 것은 발전소 수명과 발전효율, 전력거래 등에 있어 중요한 요소들이다. 전력시장에 진입하는 발전소는 전력계통의 갑작스런 불안성 상황이나 전력거래소 요청시 경사변동폭, 출력변통율, 무효전력 출력, 자동발전제어, 주파수조절량 확보 등을 수행할 수 있어야 한다. 본 논문에서는 고급공정제어기를 이용하여 운전설계계값을 효과적으로 제어 하면서 기존의 제어로직보다 전력계통상에서 요구되는 발전기 출력을 최대한 신속히 제어하는 과정을 기술하였다. 우선 보일러 마스터와 터빈 마스터, 급수 마스터로 구성된 제어로직을 설계한 뒤 이들 마스터에 대한 발전기 출력, 주증기 압력, 기수분리기 출구온도 각각의 영향을 모델링 기법을 이용하여 적합한 모델을 구했다. 각각의 모델을 고급공정제어기에 적용하고 발전기 출력제어에 대한 기존의 발전소 응답보다 좀 더 효율적이고 실제적용이 가능한 결과를 얻을 수 있도록 튜닝을 시행했으며 그 과정과 결과를 기술했다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.513-518
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• 2015

Salinity gradient power (SGP) has attracted significant attention because of its high potential. In this study, we evaluate reverse electrodialysis (RED) with various compositions of available resources. The polarization curve (I-V characteristics) shows linear behavior, and therefore the power density curve has a parabolic shape. We measure the power density with varying compartment thicknesses and inlet flow rates. The gross power density increases with decreasing compartment thickness and increasing flow rate. The net power density, which is the gross power density minus the pumping power, has a maximum value at a compartment thickness of 0.2 mm and an inlet flow rate of 22.5 mL/min. The power density in RED is also evaluated with compositions of desalination brines, seawater, river water, wastewater, and brackish water. A maximum power density of $1.75W/m^2$ is obtained when brine discharged from forward osmosis (FO) and river water are used as the concentrated and the diluted solutions, respectively.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.1
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• pp.33-38
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• 2019

This study refers to the deodorization of DDM Environmental Resource Center, which is operating abnormally in the food waste public-resource facilities that are operating nationwide, in accordance with the initial operating conditions. Issues concerning the abnormal deodorization facilities of DDM Environment Resource Center were the deodorization of composting facilities, indoor air quality problems, and overall deodorization of facilities, especially the phenomenon of stopping while operating the RTO and the phenomenon of poor spray in the wet scrubber etc. As an alternative and improvement method for converting such abnormal operation facilities into normal operation facilities, It is proposed to remove the front filter of the upper part of the fermentation tank, and to install scrubbers, air and water separator, and roll filters for dust removal etc.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.2 no.2
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• pp.19-24
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• 1991

This paper propose a new taegeuk shaped directional couper and verify the possibility of high power division rate in those directional coupler through the experiments. We took the taegeuk shaped structure in those proposed directional coupler to utilize a $3\lambda/4$ section of hybrid ring directional coupler actively, and calculated the branch admittances, which satisfied the condition of perfect matching and isolation in the center frequency, by even odd mode analyzing methodes. On the result, we knew that it can be realized a much higher power division rate than reported result in same circuit area within the producible resistance limit in the microstrip line, made the taegeuk shaped directional couplers with 0, 8, 16 dB power split ratio in the 10 GHz frequency using CGP - 502 plate, and confirmed the validity of theory through the experiments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.545-550
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• 2002

A hemolysin producing bacterial strain which belong to Vibrio species was isolated from the Kum River estuary. In the process of identification, the strain did not show characteristics of known Vibrio species; thus, the strain was designated as Vibrio sp, E10 (V. kunsan) tentatively and further identification study was carried out by comparing its bacteriological characteristics. Morphologically Vibrio sp, E10 was comma shaped rod with a polar flagellium. Clear hemolysis zones were observed with the strain against human and sheep blood agar. Hemollytic toxicity was confirmed by strong vascular Permeability and fatal toxicity against mouse was also observed. Therefore the strain was a pathogenic vibrio. Growth conditions for Vibrio sp. E10 were ranged salinity of 0$\~$$4.5\%$, pH of 6.2$\~$9.2, temperature of 14$\~$42$^{\circ}C$, respectively, 16S rDNA partial sequence of Vibrio sp, E10 showed $99\%$ homology with dozens of V. cholerae species including V, cholerae El Tor N16961 and V, snmisnfus ATCC 33653T. This strain belonged to Proteobacteria; gamma subdivision; Vibrionacea: Vibrio. But, among knorn Vibrio species no identical styains were found when using automatic bacteria identification system ($MicroLog^{TM}$system, release 4.0, Biolog Inc., USA) which evaluated the ability of metabolizing 95 kinds of carbon and nitrogen sources. Vibrio sp, E10 showed 18 and 11 different responses as compared to V. mimicus and V, cholerae, respectively.