• Title, Summary, Keyword: Reaction Disk

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A Study on the Rupture Disk Design and Application at the Two Phase Flow by Runaway Reaction at Batch Reactor (회분식 반응기에서 반응폭주에 의한 2-Phase 흐름 파열판 설계 및 적용에 관한 연구)

  • Lee, Hyung-Sub;Yun, Hee-Chang
    • Journal of the Korean Institute of Gas
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    • v.21 no.3
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    • pp.1-8
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    • 2017
  • The purpose of this study is to suggest the rupture disk design(size) and application at the two phase(gas-liquid) flow by runaway reaction at batch reactor. The definition of runaway reaction is abnormally exothermic reaction by the uncontrolled cooling water or deviated operating condition. As a result, the temperature of reactor is rapidly increasing. The causes of runaway reaction are either self-heating reaction or sleeper reaction. General methods of rupture disk size or safety valve are not suitable in the runaway reaction, because of temperature and pressure increasing rapidly in the reactor and the phases of relieving fluid is 2-phase flow. This study case of the reactor incident, the depressurization system such as safety valve and vent installed, however, the system did not relieved the pressure of reactor suitably. The orifice size of the safety valve were designed too small because the size had not been considered the phenomena and character of reaction. The batch reactor design should be considered by referring to the possibility of runaway reaction proposed in this study and the size of rupture disk design method considering 2-phase flow.

Electrochemical Studies on the Reaction of Superoxide Ion with Halocarbons in Aprotic Media

  • Jeon, Seungwon;Choi, Yong-Kook
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.649-654
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    • 1995
  • The reactivity of superoxide ion($O{_2}^{-.}$) with halogenated substrates is investigated by cyclic voltammetry and rotated ring-disk electrode method in aprotic solvents. The more positive the reduction potential of the substituted nitrile, the more facile is nucleophilic displacement by $O{_2}^{-.}$. The reaction rates of halogenonitriles with $O{_2}^{-.}$ vary according to the leaving-group propensity of halide (Br>Cl>F). The relative reaction rates of other substituted nitriles are in the order of electron-withdrawing propensity of the substituent group (CN> $C(O)NH_2$ >Ph, $CH_2CN$). The reaction of $O{_2}^{-.}$ with dihalocarbons indicates that five-membered rings can be rapidly formed by the cyclization of substrate and $O{_2}^{-.}$, and the relative rates of cyclization depend on the number of methylenic carbons {$Br(CH_2)_nBr$, [n=1<2<3>4>5]}. Mechanisms are proposed for the reaction of $O{_2}^{-.}$ with halogenated substrates.

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Laser Based Temperature Measurement of Rotating Disk Using Thermocolor (서모컬러를 이용한 회전 디스크의 레이저 온도 측정)

  • Na, Wonhwi;Yoo, JaeChern
    • Journal of Sensor Science and Technology
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    • v.22 no.1
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    • pp.49-53
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    • 2013
  • In this paper, we proposed a laser-based non-contact temperature measuring method for high speed rotating polycarbonate (PC) disk using transparency change of thermocolor. The thermocolor has abilities to change color and transparency due to a change in temperature. The thermocolor is applied on one side of polyvinylidene fluoride (PVDF) membrane. The thermocolor applied membrane is attached to inside of reaction chamber in disk. An optical system consisted of a laser beam radiator and a laser photometer is installed. Laser is irradiated at the bottom side of disk and the transmitted laser beam is detected by the laser photometer at the opposite side of disk. During the disk is rotating, laser is irradiated and detected simultaneously. The laser photometer senses the transmitted laser power and generates voltage as output. The temperature of disk can be detected during the disk is rotating up to 3000 RPM.

A Study on the Improvement of Preventive Measures for Improving the Safety of Chemical Reactor (화학반응기의 안전성 향상을 위한 예방조치 개선에 관한 연구)

  • Byun, Yoon Sup
    • Journal of the Korean Institute of Gas
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    • v.24 no.4
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    • pp.32-38
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    • 2020
  • Based on the cases of fire and explosion accident in the chemical reactor, thr problems of preventive measures installed in the chemical reactor were analyzed. The chemical reactors produce a variety of chemicals and install rupture disk to relieve the pressure that rises sharply in the event of a runaway reaction. In order to maintain the function of the rupture disk, the emissions was allowed to be discharged into the atmosphere, resulting in fire and explosion accidents. As a way to improve this, safety instrumented system based on the safety integrity level(SIL3) was applied as a preventive measures for chemical reactor. Two emergency shur-off valves are installed in series on pipe dropping raw materials for chemical reactor so that the supply of raw materials can be cut off even if only one of the two emergency shut-off valves is operated during the runaway reaction. The automatic on/off valve is installed in parallel in the supply pipe of the reaction inhibitor so that the reaction inhibitor can be injected even if only one valve is opened at the time of the runaway reaction.

Design of A Simple Disk-type 3-DOF Actuator (단순 원판형 평면 3자유도 액추에이터 설계)

  • Bach, Du-Jin;Kim, Ha-Yong;Kim, Seung-Jong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.3
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    • pp.334-340
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    • 2005
  • A disk-type 3-DOF actuator which has new principle and very simple structure is proposed. Also it utilizes the relation of bias and control fluxes produced by permanent magnets and coils, respectively, like other conventional electromagnetic actuators, but its main feature is that both the coils and permanent magnets are fixed in the stator, which makes it easy to design the shape of moving part. Operating principle is that a moving disk is driven by reaction force of Lorentz force acting on the fixed equivalent coil. Simple analytic approach and FEM analysis are performed to determine the design parameters so as to increase the driving force and distance. And some experimental results show the feasibility of the proposed actuator.

Evaluation of the SWR′s Early Pressure Variations in the KALIMER IHTS (KALIMER IHTS의 SWR 초기 압력파 거동 분석)

  • 김연식;심윤섭;김의광;어재혁
    • Journal of Energy Engineering
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    • v.11 no.2
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    • pp.122-129
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    • 2002
  • The analytical models and algorithm of the SPIKE code, which has been developed by KAERI's KALIMER team to investigate the sodium-water reaction phenomena in the liquid metal reactor, were introduced with its verification calculation results. The sodium water reaction of KALIMER IHTS was evaluated. Early stage of the sodium-water reaction consists of wave and mass transfer regimes. The pressure variations were independent of specific design features in the wave transfer regime. However in the mass transfer regime, the pressure variations were strongly dependent on cover gas volume and rupture disk set pressure. The early stage SWR analysis showed that the KALIMER IHTS with an appropriate cover gas volume and rupture disk set pressure had enough margin to its design pressure.

Microwave Induced Reduction/Oxidation Reaction by SHS Technique (마이크로파를 이용한 SHS 방법에 의한 분말의 산화-환원반응)

  • 김석범
    • Korean Journal of Crystallography
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    • v.9 no.1
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    • pp.44-47
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    • 1998
  • A reduction/oxidation reaction between A1 metal powder and SiO2 powder was performed by Self-propagating High-temperature Synthesis (SHS) reaction induced by microwave energy to produce a composite of Al2O3 and Si powders by using a 2.45 GHz kitchen model microwave oven. A Microwave Hybrid Heating(MHH) method was applied by using SiC powders as a suscepting material to raise the temperature of the disk samples and the heat increase rate of over 100℃/min were obtained before the reaction. The reaction started around 850℃ and the heat increase rate jumped to over 200℃/min after the reaction took place.

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Phenotypic and Genotypic Detection of Metallo-β-Lactamase Producing Pseudomonas aeruginosa

  • Yang, Byoung-Seon;Hong, Keun-Seok;Jung, Seung-Bong;Kwon, Young-Hoon;Jeong, Jong-Yoon;Lee, Min-Joo;Lee, Hye-In;Park, Mi-Seon;Choi, Seung-Gu
    • Korean Journal of Clinical Laboratory Science
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    • v.44 no.2
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    • pp.81-85
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    • 2012
  • This study was undertaken to evaluate phenotypic and genotypic methods for detection of Metallo-Beta-Lactamases (MBLs) among nosocomial Pseudomonas aeruginosa. Of the 50 P. aeruginosa isolates from clinical specimens, 20 were evaluated for carbapenem resistance and screened for MBL by double-disk synergy test and combined-disk test. Nineteen strains (95%) were found to be MBL producers among the 20 P. aeruginosa. MBL positives were further confirmed by Polymerase Chain Reaction (PCR). For the IMP and VIM types of MBLs, PCR analysis was performed on 19 of the 20, and 10 were positive for VIM MBL type. This study reports the validation of a simple and accurate MBL detection method that can be easily incorporated into the daily routine of a clinical laboratory. Early detection of MBL-carrying organisms, including those with susceptibility to carbapenems, is of paramount clinical importance, as it allows rapid initiation of strict infection control practices as well as therapeutic guidance for confirmed infection.Key Words : Hepatitis A virus (HAV), Anti-HAV, Hospital workers, Prevalence, Vaccination

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Synthesis and Characterization of Non-precious Metal Co-PANI-C Catalysts for Polymer Electrolyte Membrane Fuel Cell Cathodes (고분자 전해질 연료전지 캐소드용 코발트-폴리아닐린-탄소로 구성된 비귀금속 촉매의 제조 및 특성 평가)

  • Choi, Jong-Ho
    • Journal of the Korean Electrochemical Society
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    • v.16 no.1
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    • pp.52-58
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    • 2013
  • In order to overcome the cost issue for commercialization of polymer electrolyte membrane fuel cell (PEMFC), this research was conducted for replacing platinum cathode catalyst with non-precious metal catalyst. The non-precious metal catalyst (Co-PANI-C) was synthesized by the simple reduction method with polyaniline (PANI), carbon black, and cobalt precursor without any heat treatment. Characterization of new Co-PANI-C composite catalysts was done by the measurement of X-ray diffraction (XRD) and thermogravimetric analysis (TGA) for structure analysis and performed by rotating disk electrode (RDE) and rotating ring disk electrode (RRDE) for electrochemical analysis. As a result, Co-PANI-C catalyst showed 60 mV lower on-set potential for oxygen reduction reaction (ORR) than Pt/C catalyst, but the overall reduction current of Co-PANI-C catalysts by ORR was still smaller than that of Pt/C. In addition, the ORR behavior of Co-PANI-C catalysts depending on the rotation speed of electrode and the stability of Co-PANI-C catalyst under potential cycling and the performance of fuel cell conditions are also discussed.