• 자원리싸이클링
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• 제27권3호
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• pp.30-38
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• 2018

본 연구는 1173 K에서 60분 동안 유지하는 조건하에 PVC 또는 $CO-Cl_2$ 혼합가스를 각각 사용하여 환원제에 따른 ilmenite ore의 Fe 선택염화 거동에 대해 조사하였다. 환원제로 PVC를 사용한 경우, 무게 감소율은 28%로 관찰되었다. 그리고 반응관 출구부위에 생성된 응축물은 X-선 회절 분석결과 $FeCl_2$로 확인되었다. 이러한 결과로부터 ilmenite ore 내의 철은 HCl 가스와 반응하였고 $FeCl_2$ 형태로 Fe만 선택적으로 제거된 것으로 관찰하였다. 그러나 환원제로 $CO-Cl_2$ 혼합가스를 사용한 경우, 무게 감소 비율은 54%로 관찰되었으며, 실험 종료 후 반응관 출구부위에 생성된 응축물은 $FeCl_3$로 추측할 수 있었다. 이를 통해 ilmenite ore는 $CO-Cl_2$ 혼합가스와 반응하여 $FeCl_3$ 및 $TiCl_4$ 반응물 형태로 동시에 제거되는 것으로 관찰되었다. 다만 반응후 ilmenite ore의 X선 회절 결과에서 Fe는 대부분 제거되었음을 보여주었다.

• 한국연초학회지
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• 제29권2호
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• pp.146-151
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• 2007

Gas phase and particulate phase radicals in mainstream cigarette smoke were determined Electron Spin Resonance(ESR) spectroscopy. The free radicals in particulate phase have been investigated by benzene extract of Cambridge Filter Pad containing the smoke condensate. Spin trapping method in conjunction with ESR was used to investigate free radicals in the gas phase of cigarette smoke. Several analytical experiments were conducted in order to determine the optimal conditions for maximum signal intensities and reproducibility of results. All the tests were optimized and normalized using the University of Kentucky 2R4F reference cigarette. The optimal conditions were 0.6 mL for analysis volume of ESR, $4{\sim}5\;mL$ for collection volume of spin-adducts, and PBN for quantification of free radicals in gas phase. The radical levels of Kentucky 2R4F cigarettes were found $2.18{\times}10^{14}\;spins/cig.$ and $2.10{\times}10^{15}\;spins/cig.$ in gas phase.

• Corrosion Science and Technology
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• 제22권5호
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• pp.351-358
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• 2023

Although many thermal power plants use heat recovery systems, high exhaust gas temperatures are maintained due to corrosion at dew points and ash deposits caused by condensate formation. The dew point of exhaust gas is primarily determined by the concentration of SO₃ and steam, and various experiments and calculation equations have been employed to estimate it. However, these methods are known to be less suitable for exhaust gases with low SO₃ concentrations. Therefore, in this study, since the temperature of the exhaust gas is expected to decrease due to the low-load operation of the coal-fired power plant, sulfuric acid condensation and low-temperature corrosion are anticipated. We aimed to conduct a quantitative evaluation to propose ways to prevent damage by limiting operating conditions and improving facilities. The experimental results showed that the corrosion rate increased linearly with rising temperatures at a certain sulfuric acid concentration. Furthermore, variations in sulfuric acid concentrations generated during the current power plant operation process did not significantly affect the dew point, and the dew point of sulfuric acid under these conditions was observed to be between 120 - 130 ℃.

• 한국수산과학회지
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• 제11권4호
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• pp.183-188
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• 1978

피등어꼴뚜기를 가열가공할 때 발생하는 취기를 제거할 목적으로 취기성분을 gas chromatography로 공석한 것을 단보로서 요약하면 다음과 같다. 1. 피등어꼴뚜기 취기성분 추출에는 methanol이 가장 적합하였다. 2. 빙수trap에서 25개 peak, dry ice-acetone trap에서 32개 peak가 검출되었고, 그 중 acetic acid, butyric acid, iso-valeric acid, valeric acid, caproic acid 등 5성분을 동정하였다. 3. 액체질소 trap의 head space vapor에서 11개 peak가 검출되었고, 그 중 mothylamine, trimethylamine, dimethylamine, ethylamine, isopropylamine등 5성분을 동정하였다.

• 설비공학논문집
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• 제12권9호
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• pp.817-824
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• 2000

The fluidized solid particles not only increase heat transfer rates but have a cleaning function eliminating contaiminated substances caused from condensate water. An experiment was performed to measure heat transfer rates and pressure drops in a fluidized heat exchanger with circulating solid particle for constant heat transfer rate. As a results, the heat transfer rate increased by 26.9~2.6%, heat transfer coefficient by 11.9~2.7%, and pressure drop by 79.1~10.9% at the gas velocity of 6.1 ~12.1 m/s and solid particle flow rate of 100~50 kg/h with the heat exchanger of H: 50 mm, $D_p=2 in,\; and\;D_{BP}$=30 mm.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 추계학술대회
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• pp.55-57
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• 2012

Suez운하를 이용할 경우 부산항에서 로테르담항까지의 수송거리가 11,340마일이 북극해 항로를 이용할 경우 6,860마일로 36%가 줄고 수송기간도 10일 이상 단축되므로 북극해항로를 통한 유럽과 아시아간의 상업적인 수송이 이뤄진다면 해운회사들의 물류비용이 대폭 절감될 것으로 전망된다. 이런 시점에서 2011년 9월 한-러 국장급 해운회담이 열렸으며, 2011년 11월 23일 부산 누리마루 APEC House에서 "북극해항로 상업운항의 현황과 전망"이라는 주제로 국제세미나가 개최 되었다. 현재 북극해 항로를 통과한 선박이 2007년 2척, 2008년 3척, 2009년 4척, 2010년 10척이었던 것이 2011년에는 34척 총 82만톤의 통과 수송이 이뤄졌고, 러시아 북극내의 물동량은 2백20만톤에 달할 것으로 전망되었으며, 2012년의 통과 물동량은 100만톤을 상회 할 것으로 전망된다. 이에 북극해 항로에 대한 소개와 빙하지역을 항해하는 선박에 대한 운항지침에 대하여 검토해보고저 한다.

• Archives of Pharmacal Research
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• 제5권2호
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• pp.71-77
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• 1982

Improvements in the analytical methodology used in the gas chromatographic/mass spectral analysis of phenolic compounds from cigarette smoke are described. For the direct analysis of crude samples, pyridine extraction and the glass capillary column GC was used for the separation of phenolics as trimethylsilyl derivativatives. The separations of cigarette smoke on Carbowax 20M and SE-54 wall coated open tubular columns are given. Improved methodology for the routine quantitation of the identified components using the computer-controlled multiple ion selection technique of MS presented. Considerations pertaining to routine analyses of a multitude of complex smoke samples are also discussed.

• 한국안전학회지
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• 제35권3호
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• pp.96-104
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• 2020

The numerical simulations were conducted to investigate the thermal-fluid phenomena occurred inside the experimental apparatus during a PCCS, used to remove heat released in accidents from a containment of light water nuclear power plant, operation. Numerical simulations of the flow and heat transfer caused by wall condensation inside the containment simulation vessel (CSV), which equipped with 18 vertical heat exchanger tubes, were conducted using the commercial computational fluid dynamics (CFD) software ANSYS-CFX. Shear stress transport (SST) and the wall condensation model were used for turbulence closure and wall condensation, respectively. The simulation using the actual size of the apparatus. However, rather than simulating the whole experimental apparatus in consideration of the experimental cases, calculation resources, and calculation time, the simulation model was prepared only in CSV. Selective simulation was conducted to verify the effects of non-condensable gas(NC gas) concentration, CSV internal pressure, and wall sub-cooling conditions. First, as a result of the internal flow of CSV, it was observed that downward flow due to condensation occurred surface of the vertical tube and upward flow occurred in the distant place. Natural convection occurred actively around the heat exchanger tube. Due to this rising and falling internal flow, natural circulation occurred actively around the heat exchanger tubes. Next, in order to check the performance of built-in condensation model using according to the non-condensable gas concentration, CSV internal flow and wall sub-cooling, the heat flux values were compared with the experimental results. On average, the results were underestimated with and error of about 25%. In addition, the influence of CSV internal pressure and wall sub-cooling was small, but when the condensate was highly generated due to the low non-condensable gas concentration, the error was large compared to the experimental values. This is considered to be due to the nature of the condensation model of the CFX code. However, in spite of the limitations of CFD, it is valid to use the built-in condensation model of CFD for PCCS performance prediction from a conservative perspective.

• 플랜트 저널
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• 제9권3호
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• pp.38-42
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• 2013

지속적인 유가 상승과 환경규약 및 안전성, NIMBY현상 등의 문제로 해상 가스전에 대한 관심이 높아지고 있다. LNG-FPSO는 해양 가스전에서 채취된 천연가스의 불순물을 제거하고, condensate와 LPG를 회수하며, 정제된 가스를 이송 가능한 형태로 액화시키는 최첨단 해양플랜트이다. 반면 작업 시 해상 환경에 많은 영향을 받으므로 선체 운동을 고려한 전처리 공정 효율을 파악하고 설계에 반영해야 한다. 본 연구는 LNG-FPSO의 선체 운동 영향 및 제한된 선상 공간의 최적화를 고려한 해상 전처리 기술을 개발하기 위한 기초 연구이다. 이에 아민 흡수공정과 멤브레인 공정을 혼합한 hybrid 공정을 검토하였으며, 일반 아민흡수공정에 비하여 낮은 용매 순환량, 낮은 열용량, 작은 컬럼 크기가 요구되어 해상용 전처리 공정에 적합함을 확인하였다. 이것은 또한 6자유도 운동 실험 및 CFD 해석을 병행하여 시뮬레이션을 가시화함으로써 다양한 해상상태에 따른 LNG-FPSO의 공정 효율을 검토할 수 있다.

• 한국가시화정보학회지
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• 제14권2호
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• pp.18-24
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• 2016

This paper presents an experimental investigation to visualize cross-sectional two-phase flow structure and identify liquid-gas interface for condensation of steam at a low mass flux in a slightly inclined tube using the axial-viewing technique, which permits to look directly into flow during condensation of steam. In this technique, two-phase flow is viewed along the axis of a pipe by locating a high-speed video camera in front of a viewer that is fitted at the outlet of the pipe. A short section of the pipe is illuminated and is recorded through the viewer, which is kept free of liquid by mildly introducing air. Experiments were conducted in a pipe of 19.05 mm in inner diameter at atmospheric pressure. Cross-sectional two-phase flow structure is obtained at a steam mass flux of $2.62kg/m^2s$ as a function of steam quality in the range from 0.5 to 0.9. The results show that stratified-wavy flow is a unique flow pattern observed in the scope of the present study. Condensate film thickness, stratification angle and void fraction were measured from the obtained flow structure images. Finally, heat transfer coefficient was calculated using the measurement data and discussed in comparison with existing correlations.