• Title, Summary, Keyword: Melting temperature

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A study on the Dioxin behavior in the process of representative pyrolysis/gasfication/melting plant (대표적인 열분해가스화 용융시설의 공정별 다이옥신 배출거동에 관한 연구)

  • Shin, Chan-Ki;Shin, Dae-Yun
    • Journal of environmental and Sanitary engineering
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    • v.22 no.1
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    • pp.1-16
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    • 2007
  • The incineration process has commonly used for wastes amount reduction and thermal treatments of pollutants as the technologies accumulated. However, the process is getting negative public images owing to matter of hazardous pollutants emission. Specially dioxins became a main issue and is mostly emitted from municipal solid wastes incineration. In this reason, pyrolysis/gasfication/melting process is presented as a alternative of incineration process. The pyrolysis/gasfication/melting process, a novel technology, is middle of verification of commercial plant and development of technologies in Korea. But the survey about the pollutant emission from the process, and background data in these facilities is necessary. So in this survey, it Is investigated that the behavior of dioxins in three pyrolysis/gasfication/melting plant (S, T, P) of pilot scale. In case of S plant, concentration of dioxins shows high at latter part of cogenerated boiler and stack which are operate on low temperature conditions than a latter parts of pyrolysis and melting furnace which are operate on high temperature condition. Concentration of gas phage dioxins had increased after combusted gas passed cogenerated boiler and this is attributed to react of precursor materials such as chlorobenzene and chlorophenol. Concentration of dioxins in T plant showed lower levels at latter part of cooling equipment which are operate with water spray type on low temperature conditions than a latter parts of gasfied melting furnace which are operate on high temperature condition. Removal efficiency of dioxins at gas treatment equipment was 78.8 %. Concentration of dioxins in P plant was low at latter part of SDA/BF which is operate at low temperature conditions than a latter parts of pyrolysis gasfied chamber which are operate at high temperature condition. Removal efficiency of dioxins of SDA/BF was 85.9 % and therefore, it showed high efficiency at those of stoker type incineration facility. However, concentration of dioxins which emitted at high temperature condition were low in three facilities and satisfied present standard emission level of dioxins. To consider the distribution ratio of dioxins, Particulate phase dioxins at S and P plants showed similar ratio with which shows in current stoker type for middle scale domestic waste incineration facility. It is necessary to continuos monitoring the ratio of distribution of dioxins in T plant in because ratio of gas phage dioxins showed high.

The Experimental Study on Heat Transfer during Melting Process in the Low Temperature Heat Storage System(Ice on Coil Type) (Ice on Coil형 저온 잠열 축열시스템에서의 용융과정시 열전달에 관한 실험적 연구)

  • Kim, Y.K.;Kim, D.C.;Kim, I.G.;Choi, K.K.;Yim, C.S.
    • Solar Energy
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    • v.19 no.1
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    • pp.19-27
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    • 1999
  • In this study, basic design data which were required for development of highly efficient ice storage system with low temperature latent heat were experimentally obtained. The ice storage system considered in this study was the one that has been widely used in the developed country and called the ice-on-coil type. Using the system, the ice storage performance for various design parameters which were the flow direction and the inlet temperature of the secondary fluid was tested. In addition, the clockwise variation of the heat transfer characteristics of the PCM in the ice storage tank were investigated. During the melting processes in the ice storage tank with several vertical tubes, decrease of the solid-liquid interface area, which was the heat transfer area, between the floating ice and the water made the decreasing rate of IPF less. Also, the total melting energy for the upward flow of the secondary fluid was higher than that for the downward flow during the melting process, but this trend did not appear if the initial temperature of the PCM was $4^{\circ}C$. The average ice recovery efficiency for the upward flow of the secondary fluid was higher than that for the downward flow.

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The Effect of Electron Beam Irradiation on Discoloration and Thermal Property of HDPE Filled with Antioxidants and UV Stabilizers (전자선 조사에 따른 산화방지제 및 자외선안정제 첨가 HDPE의 변색 영향과 열적 특성 분석)

  • Jeun, Joon Pyo;Jung, Seung Tae;Kim, Hyun Bin;Oh, Seung Hwan;Kang, Phil Hyun
    • Journal of Radiation Industry
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    • v.7 no.1
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    • pp.23-28
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    • 2013
  • In this study, we fabricated high density polyethylene (HDPE) composites filled with antioxidants and UV stabilizers. The electron beam irradiation on the fabricated composites was carried out over a range of absorbed doses from 50 to 200 kGy to confirm the changes of discoloration. The changes of discoloration were characterized using a color difference meter and FT-IR for confirming the changes of the color difference and structural change. It was observed that the color difference of IRGANOX 1010-, IRGAFOS 168-, and TINUVIN 328- added HDPE was higher than that of the control HDPE by electron beam irradiation. The melting temperature of UV stabilizer-added HDPE was not significantly changed by electron beam irradiation. However, the melting temperature of phenol-containing antioxidant-added HDPE was increased with increasing the absorbed dose. And the melting temperature of phosphorus-containing antioxidant-added composite was decreased with increasing the absorbed dose.

Dielectric Properties of P(VDF/TrFE) Thin Films Prepared by Vapor Deposition Method (진공증착법으로 제조된 P(VDF/TrFE) 박막의 유전특성)

  • Jeong, Mu-Yeong;Yun, Jong-Hyeon;Lee, Seon-U;Park, Su-Hong;Yu, Do-Hyeon;Lee, Deok-Chul
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.1
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    • pp.1-5
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    • 2001
  • P(VDF/TrFE) copolymer thin films with 70/30 and 80/20 mol% VDF (polyvinylidene fluoride) and TrFE (trifluoroethylene) rates were prepared by using a vapor deposition method, During thin films were prepared, the substrate temperatures were maintained at 30 $^{\circ}C$ and 120 $^{\circ}C$, and the heating source temperature was fixed at 350 $^{\circ}C$. Contary to PVDF homopolymer, P(VDF/TrFE) copolymers showed the Curie point(Tc) below the melting point. The Curie point (Tc) and the melting point of the P(VDF/TrFE) copolymers were changed as a function of substrate temperature and the VDF mol%. The Curie point and the melting point of P(VDF/TreFE) thin films decreased and increased with increasing substrate temperature, respectively. Also with increasing VDF mol%, the melting point decreased slightly, however the Curie point increased.

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Effect of melting temperature and additives on transparency of Bi based Transparent Dielectric Layer in Plasma Display Panel

  • Park, Ji-Su;Han, Sun-Mi;Hwang, Jong-Hee;Kim, Chang-Yeul;Choi, Duck-Kyun
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1229-1232
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    • 2005
  • We report the method of preventing the grey color of Bi based glass frits caused by reduction of $Bi_2O_3$. To prevent reduction of $Bi_2O_3$, we controlled the melting temperature. Low melting temperature reduces the reduction of $Bi_2O_3$ and that makes clarity transparent glass cullets. After firing, glass frits that melted at lower temperature showed better transparency. To prevent the browning, we used some additives like CuO, $CeO_2$, CoO and $TiO_2$. The colors of glass cullets were varied according to additives. After firing, dielectric layer contained additives showed better transparency than the one without additives. In the point of reaction between dielectric layer and Ag electrode, CuO was the most effective additive in preventing the yellowing.

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Finite Element Analysis of Large-Electron-Beam Polishing-Induced Temperature Distribution (대면적 전자빔 폴리싱 공정 시 발생하는 온도 분포 유한요소해석 연구)

  • Kim, J.S.;Kim, J.S.;Kang, E.G.;Lee, S.W.;Park, H.W.
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.22 no.6
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    • pp.931-936
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    • 2013
  • Recently, the use of large-electron-beam polishing for polishing complex metal surfaces has been proposed. In this study, the temperature induced by a large electron beam was predicted using the heat transfer theory. A finite element (FE) model of a continuous wave (CW) electron beam was constructed assuming Gaussian distribution. The temperature distribution and melting depth of an SUS304 sample were predicted by changing electron-beam polishing process parameters such as energy density and beam velocity. The results obtained using the developed FE model were compared with experimental results for verifying the melting depth prediction capability of the developed FE model.

Effect of Applying Pressure of High Pressure Diecasting Process Using Salt core (용탕단조 시 저온염코어 적용 가압력의 영향)

  • Lee, Jun-Ho;Moon, J.H.;Lee, Dock-Young
    • Journal of Korea Foundry Society
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    • v.28 no.3
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    • pp.136-140
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    • 2008
  • A new concept of salt core, a melting temperature of which is lower than the solidus temperature of cast alloy, was introduced to produced an integrated casting part having a complicated inner shape or requiring under-cut in high pressure die casting or squeeze casting process. The main goal of this study is to develop a new integrated net-shape forming technology using fusible core of lower melting temperature than that of a casting alloy. This integrated net-shape forming technology would be very successful and cost-effective for producing the integrated products having a complicated inner shape or requiring under-cut. The technology for measuring and evaluating a various property of fusible core such as a thermal conductivity and thermal expansion coefficient, melting temperature was established. Also, the work space can be cleaned without a pollution inducing products.

A Study on the Temperature Control of a TV-Glass Melting Furnace Using the Conventional Advanced Control (고전고급제어(Conventional Advanced Control)를 이용한 TV 브라운관 유리 용해로의 온도제어에 관한 연구)

  • Moon, Un-Chul;Kim, Heung-Shik
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.9
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    • pp.822-830
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    • 2000
  • A conventional advanced control algorithm is proposed in this paper for improved temperature regulation of a TV-glass melting furnace. The TV-Glass melting furnace is a typical MIMO(Multi-Input Multi Output) system which is subject to various thermal disturbances. Because of its complexity, a detailed mathematical model of the furnace is hard to establish. To design a temperature control control system of the furnace, major input-output variables are selected first, and simple FOPDT(First Order Plus Dead Time) models are established based on the physical meaning and experimental process data. Based on the FOPDT models, a multi-loop control system composed of cascade and single loops are designed for effective control of the MIMO system. Practical implementation on the 150 ton/day furnace using the DCS(Distributed Control System) showed that the proposed control technique performs better than manual control.

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Melting of Ice Inside a Horizontal Cylinder under the Volume Change (수평원관내 체적변화를 고려한 얼음의 용용시 전열특성에 관한 연구)

  • 조남철;김동춘;이채탈;임장순
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.12
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    • pp.1266-1274
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    • 2001
  • Heat transfer phenomena during melting process of the phase change material (ice) was studied by numerical analysis and experiments. In a horizontal ice storage tube, the natural convection caused an increase in melting rate. However, the reduction of the heating surface area caused a decrease in melting rate. Therefore, during the melting process of ice in a horizontal cylinder, the reduction of the heating surface area should be considered. Under the same heating wall and initial water temperature condition, the melting rate became higher for $V_s/V_tot/=0.545 \;than \;that\; for\; V_s/V_tot$/=1.00 due to the difference in the reduction of heating surface area. A modified melting model considering the equivalent thermal conductivity of liquid phase and volume reduction was proposed. The results of the model were compared with the measured values and found to be in good agreement.

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A Study on the Melting Morphology of Graphite in Cast Iron

  • Lim, Chang-Hee;Ra, Hyung-Yong
    • Journal of Korea Foundry Society
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    • v.5 no.4
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    • pp.243-257
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    • 1985
  • Many authors have studied the solidification process of cast iron and the effect of grain boundaries in austenite shell on the growth of spheroidal graphite. But, the studies on the melting morphology of cast iron are rare and the effect of grain boundaries in austenite shell on the melting procedure of spheroidal graphite cast iron is unknown. Therefore, in this work, the melting procedure of cast iron and the role of grain boundaries in austenite shell on the melting of spheroidal graphite have been studied. The main results are summarized as follows. 1. In white cast iron containing silicon, melting initiates at the interface between austenite matrix and temper carbon which was decomposed from $Fe_3C$ during heating. 2. In gray cast iron, melting initiates at the boundary of eutectic cell where elements with low melting temperature are condensed. The dissolution of kish graphite is difficult. 3. In spheroidal graphite cast iron containing little phosphor, melting initiates at the outer region of austenite shell in which silicon is condensed. In this case, grain boundaries in austenite shell give little effect on the melting procedure of spheroidal graphite. 4. In spheroidal graphite cast iron containing phosphor above 0.3 wt%, its melting phenomena are changed with heating rate due to the existence of steadite. In this case, it can be concluded that liquid phase of steadite, which segregated on outer region of austenite shell, moves to spheroidal graphite-austenite interface along the grain boundaries in austenite shell.

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