• Title/Summary/Keyword: Single Phase Operation

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Experimental Study on N2 Impurity Effect in the Pressure Drop During CO2 Mixture Transportation (CO2 파이프라인 수송에서의 N2 불순물이 압력강하에 미치는 영향에 대한 실험적 연구)

  • Cho, Meang-Ik;Huh, Cheol;Jung, Jung-Yeul;Baek, Jong-Hwa;Kang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.2
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    • pp.67-75
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    • 2012
  • Carbon-dioxide capture and storage (CCS) process is consisted by capturing carbon-dioxide from large point source such as power plant and steel works, transporting and sequestrating captured $CO_2$ in a stable geological structure. During CCS process, it is inevitable of introducing impurities from combustion, capture and purification process into $CO_2$ stream. Impurities such as $SO_2$, $H_2O$, CO, $N_2$, Ar, $O_2$, $H_2$, can influence on process efficiency, capital expenditure, operation expense of CCS process. In this study, experimental apparatus is built to simulate the behavior of $CO_2$ transport under various impurity composition and process pressure condition. With this apparatus, $N_2$ impurity effect on $CO_2$ mixture transportation was experimentally evaluated. The result showed that as $N_2$ ratio increased pressure drop per mass flow and specific volume of $CO_2-N_2$ mixture also increased. In 120 and 100 bar condition the mixture was in single phase supercritical condition, and as $N_2$ ratio increased gradient of specific volume change and pressure drop per mass flow did not change largely compared to low pressure condition. In 70 bar condition the mixture phase changed from single phase liquid to single phase vapor through liquid-vapor two phase region, and it showed that the gradient of specific volume change and pressure drop per mass flow varied in each phase.

Highly Efficient Biogas Upgrading Process Using Polysulfone Hollow Fiber Membrane at Low Temperature (폴리술폰 중공사막을 이용한 바이오가스 고순도화 고효율 저온 분리 공정)

  • Kim, Se Jong;Han, Sang Hoon;Yim, Jin Hyuk;Lee, Chung Seop;Chang, Won Seok;Kim, Gill Jung;Ha, Seong Yong
    • Membrane Journal
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    • v.32 no.2
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    • pp.140-149
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    • 2022
  • In this study, the conditions of low temperature and high pressure of biogas upgrading process using polysulfone membrane have been designed and tested to achieve the high recovery and efficiency corresponding to those of the highly selective polymeric materials. Polysulfone hollow fiber membrane with 4-component dope solution was spun via non-solvent induced phase separation. The hollow fiber membrane was mounted into a 1.5 inch housing. The effective area was 1.6 m2, and its performance was examined in various operation temperatures and pressures. CO2 and CH4 permeances were 412 and 12.7 GPU at 20℃, and 280 and 3.6 GPU at -20℃, respectively, while the CO2/CH4 selectivity increased from 32.4 to 77.8. Single gas test was followed by the mixed gas experiments using single-stage and double stage where the membrane area ratio varied from 1:1 to 1:3. At the single-stage, CH4 purity increased and the recovery decreased as the stage-cut increased. At the double stage, the area ratio of 1:3 showed the higher CH4 recovery as decreasing the operation temperature at the same purity of CH4 97%. Finally, polysulfone hollow fiber membranes have yielded of both CH4 purity and recovery of 97% at -20℃ and 16 barg.

A Fully-Integrated Low Phase Noise Multi-Band 0.13-um CMOS VCO using Automatic Level Controller and Switched LC Tank (자동 크기 조절 회로와 Switched LC tank를 이용한 집적화된 저위상 잡음 다중 대역 0.13-um CMOS 전압 제어 발진기)

  • Choi, Jae-Won;Seo, Chul-Hun
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.1
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    • pp.79-84
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    • 2007
  • In this paper, a fully-integrated low phase noise multi-band CMOS VCO using automatic level controller (ALC) and switched LC tank has been presented. The proposed VCO has been fabricated in a 0.13-um CMOS process. The switched LC tank has been designed with a pair of capacitors and two pairs of inductors switched using MOS switch. By using this structure, four band (2.986 ${\sim}$ 3.161, 3.488 ${\sim}$ 3.763, 4.736 ${\sim}$ 5.093, and 5.35 ${\sim}$ 5.887 GHz) operation is achieved in a single VCO. The VCO with 1.2 V power supply has phase noise of -118.105 dBc/Hz @ 1 MHz at 2.986 GHz and -113.777 dBc/Hz @ 1 MHz at 5.887 GHz, respectively. The reduced phase noise has been approximately -1 ${\sim}$ -3 dBc/Hz @ 1 MHz in the broadest tuning range, 2.986 ${\sim}$ 5.887 GHz. The VCO has consumed 4.2 ${\sim}$ 5.4 mW in the entire frequency band.

Characteristics of π-shaped Ultrasonic Motor

  • Lim Kee-Joe;Park Seong-Hee;Yun Yong-Jin;Park Cheol-Hyun;Kang Seong-Hwa;Lee Jong-Sub
    • Journal of Electrical Engineering and Technology
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    • v.1 no.2
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    • pp.241-245
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    • 2006
  • In this paper, the design and characteristics of a $\pi-shaped$ ultrasonic motor that is applicable to optical zoom operation of a lens system for mobile phones are investigated. Its design and simulation of performances are carried out by FEM (finite element method) commercial software. As a simulation result, by applying voltage with single phase, a combined vibration is produced at the surface of a stator arm. A prototype of the motor is fabricated and its outer size is $8*4*2mm^3$ including the cylindrical steel rod of 2 mm in diameter as the rotor. The motor exhibits a maximum speed of 500 rpm and a power consumption of 0.3 W when driven at 20 Vpp and 64 kHz.

An Implementation of a Current Controlled Bi-directional Inverter with ZVT Switching (ZVT 스위칭 되는 전류제어형 양방향 인버터의 구현)

  • 李 星 龍;高 晟 勳;金 成 佑
    • The Transactions of the Korean Institute of Power Electronics
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    • v.7 no.2
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    • pp.129-136
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    • 2002
  • A single-phase inverter using a diode bridge-type resonant circuit to implement ZVT(Zero Voltage Transition) switching is presented. It Is shown that the ZACE(Zero Average Current Error) algorithm based Polarized ramptime current control can provide a suitable interface between DC link of diode bridge-type resonant circuit and the inverter. The current control algorithm is analyzed about how to design the circuit with auxiliary switch which can ZVT operation for the main power switch. The simulation and experimental results would be shown to verify the proposed current algorithm, because the main Power switch is turn on with ZVT and the hi-directional inverter is operated.

Cost-Effective APF/UPS System with Seamless Mode Transfer

  • Lee, Woo-Cheol
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.195-204
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    • 2015
  • In this paper, the development of a cost-effective active power filter/uninterruptible power supply (APF/UPS) system with seamless mode transfer is described. The proposed scheme employs a pulse-width-modulation (PWM) voltage-source inverter and has two operational modes. First, when the source voltage is normal, the system operates as an APF, which compensates for the harmonics and power factor while boosting the DC-link voltage to be ready for the disturbance, without an additional DC charging circuit. A simple algorithm to detect the load current harmonics is also proposed. Second, when the source voltage is out of the normal range (owing to sag, swell, or outage), it operates a UPS, which controls the output voltage constantly by discharging the DC-link capacitor. Furthermore, a seamless transfer method for the single-phase inverter between the APF mode and the UPS mode is also proposed, in which an IGBT switch with diodes is used as a static bypass switch. Dissimilar to a conventional SCR switch, the IGBT switch can implement a seamless mode transfer. During the UPS operation, when the source voltage returns to the normal range, the system operates as an APF. The proposed system has good transient and steady-state response characteristics. The APF, charging circuit, and UPS systems are implemented in one inverter system. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype APF/UPS system rated at 3 kVA.

Evaluation of Construction RCB Exterior Wall Formwork according to Placing Height on Nuclear Power Plant

  • Song, Hyo-Min;Sohn, Young-Jin;Shin, Yoonseok
    • Journal of the Korea Institute of Building Construction
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    • v.15 no.6
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    • pp.653-660
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    • 2015
  • Technologies for reducing construction duration are key factors in nuclear power plant construction projects, as a reduction in construction duration at the construction phase leads to a reduction in construction cost and an increase in profits through the early operation of the nuclear power plant. To analyze the constructability of the height of single-layer placement of formwork for the Reactor Containment Building (RCB) exterior wall through lateral pressure according to the height of concrete placement, the deformation criteria for formwork, and a new form design, 'MIDAS GEN (hereinafter referred to as MIDAS)' is used in this study. The cost and workload of formwork are derived according to the unit of height of the RCB exterior wall. Based on the result, it was found that the higher the RCB exterior wall, the higher the material cost, and the less the construction duration and the less the total number of formwork layers. Based on this result, it is believed that the material cost and the construction duration can be appropriately determined according to the formwork height.

A Study on the Power Quality Characteristics of Customers by the Operation of Single Phase PV System (단상용 태양광발전의 연계에 의한 수용가 전력품질 특성에 관한 연구)

  • Kim, Byung-Ki;Park, Oh-Sung;Kim, Byung-Mok;Rho, Dae-Seok
    • Proceedings of the KAIS Fall Conference
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    • 2010.11a
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    • pp.155-158
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    • 2010
  • 태양광전원이 연계되어 운용되고 있는 저압배전선로에 Sag, Swell 발생에 따른 태양광전원의 불안정한 운전과 태양광전원의 높은 왜형율의 Harmonic 발생에 따른 배전계통의 보호계전기(OCGR) 동작 등 전력 품질에 있어서 문제점이 발생되고 있다. 이러한 문제점은 사회적, 경제적 손실을 초래하게 되어, 전력품질(Sag, Swell, Harmonic, 모터기동)특성해석이 중요하다. 따라서 본 논문에서는 태양광전원이 연계되어 정상 운용 중인 배전계통에 대한 전력품질특성시험을 수행하기 위하여, 모의 배전계통장치와 모의 태양광전원장치, Labview용 감시제어장치로 구성한 태양광전원용 전력품질시험장치를 제작하였다. 이 시험장치를 이용하여 태양광전원 연계 시 Sag, Swell, Harmonic, 모터기동에 대한 시험을 수행하여 태양광전원이 배전계통에 미치는 영향과 특성을 분석하였다.

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Balancing Technic Based on Rotor Dynamics Analysis of Test Rig (Test Rig 동특성 분석에 따른 밸런싱 기술 적용)

  • Hwang, Dukyoung;Jung, Chonwoo;Park, Insun;Shin, Dongmin;Song, Jinseok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.27 no.2
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    • pp.204-212
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    • 2017
  • The rotor dynamics and balancing technic for rotating equipment during engineering and manufacture stage are to be carefully considered in order to minimize the operation troubles regarding vibration during commissioning stage. In this paper, the test rig, which includes the disks as balancing plane, is designed and manufactured, so that the characteristic of rotor dynamics can be analyzed such as critical speed and mode shape. The critical speed predicted through natural frequency analysis is verified by the actual measurement on bearing housing vibration during start-up condition of test rig. The low speed balancing and the operating speed balancing test are performed respectively with consideration of first critical speed, and the residual unbalance amounts are estimated in accordance with the relevant method described in API standard. In addition, the single and dual plane balancing are carried out on main disk and trim disk depended on phase information at each balancing step.

Process Development of a Standard Operating Procedure (SOP) for the Manufacturing of Standardized Distribution Boards (규격화된 분전반 제작을 위한 표준작업절차(SOP)의 공정 개발)

  • Ko, Wan-Su;Lee, Byung-Seol;Choi, Chung-Seog
    • Journal of the Korean Society of Safety
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    • v.33 no.5
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    • pp.21-27
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    • 2018
  • The purpose of this study is to develop a SOP (Standard Operating Procedure) for a distribution board that can monitor the leakage current of a load distribution line in real time. The developed distribution board was fabricated by applying IEC 61439-1. It consists of the distribution board and an alarm device. The work process for making the distribution board was compliant with the KEMC (Korea Electrical Manufacturers Cooperative) regulations. And the AC distribution board range is 1,000 V. In addition, the voltage in DC is less than 1500 V. The distribution board receives a 3-phases and 4-wires power supply system and can supply power to the load of a maximum of 32 single or three phase distribution circuits. Also, leakage current measured on the power distribution board was used by sensors installed. The SOP of the developed distribution board consists of the installation standards for the short circuit alarm device and sensor, the surge protection device, switches and indication lamps, and other devices. The operation procedure was prepared so that each manufacturing step of the distribution board must be confirmed by the persons in charge of preparation, production, quality control and approval before moving forward to the next step.