• Title/Summary/Keyword: Minimum Ignition Energy(MIE)

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Measurement of Minimum Ignition Energy by Electrostatic Discharge for Flammable Ternary Gas Mixtures (3성분계 인화성 혼합가스의 최소점화에너지 측정에 관한 연구)

  • Choi, Sang-Won
    • Journal of the Korean Society of Safety
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    • v.28 no.1
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    • pp.29-34
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    • 2013
  • When flammable gases are mixed with air or oxygen in the explosion concentration range and are ignited by sufficiently large electrostatic discharge energy, they may explode causing severe disaster in workplace. The minimum ignition energy(MIE) of single gas-air mixtures has been already investigated by many research, but the MIE of mixtures of more than ternary gas mixture is not examined yet. The purpose of this study is to investigate the MIE of a ternary gas(methane, ethylene, hydrogen, propane) mixtures experimentally. The results of our experiment show that the ignition of a methane-ethylene-air, methane-hydrogen-air, methane-propane-air, ethylene-hydrogen-air, ethylene-propane-air and hydrogen-propane-air mixture due to electrostatic discharge energy primarily depends on that the mixture: the MIE decreases gradually with the increase of having the lower MIE than other mixture ratio in the normal atmospheric pressure.

A Study on Minimum Ignition Energy by Controlled Discharge Energy (방전에너지 제어에 의한 최소점화에너지의 고찰)

  • Choi, Sang-Won;Ohsawa, Atsushi
    • Journal of the Korean Society of Safety
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    • v.22 no.1 s.79
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    • pp.36-39
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    • 2007
  • It is important to know Minimum Ignition Energy(MIE) of flammable materials for ignition hazard of chemical processes etc.. Currently a capacitor discharge is used mainly to measure the MIE. Then, it is impossible to control actively discharge energies and discharge time because the MIE measurement uses a high voltage capacitor and fixed capacitor. However, the control of discharge energy and discharge time will be convenient if self-sustain discharge is used. In this paper, we measured the MIE by self-sustain discharge of a pulse shape to propose the new measuring method of the MIE. AS a result, ignition energies are increased gradually as discharge duration time gets longer, and discharge current grows larger. Also, an arc discharge and a glow discharge occurred during the experimental period, and the ignition by glow discharges happened when discharge duration time was $90{\mu}s$, discharge current was 8A and 1A Especially, the MIE occurred the 0.05mm and 0.08mm of the gap distance between discharge electrode in the same discharge duration time.

A Study on Minimum Ignition Energy by Controlled Discharge Energy (방전에너지 제어에 의한 최소점화에너지의 고찰)

  • 최상원;대택돈
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2003.05a
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    • pp.303-308
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    • 2003
  • 가연성 물질의 최소점화에너지(Minimum Ignition Energy; MIE)를 아는 것은 화학공정 등의 안전성 평가에 중요한 것이다. 현재 MIE의 측정에는 주로 용량성 불꽃방전이 이용되고 있다. 용량이 큰 커패시터를 이용한 방전에서는 MIE가 크게 되는 경향이 있고, MIE가 회로정수에 의존한다는 것이 실험적으로 알려져 있다. 이 현상은 방전회로의 시정수와 점화를 위한 에너지의 수송시간과의 관계에 의해 이론적으로 설명하는 것이 가능하게 되었다.(중략)

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Relationship Between the Minimum Ignition Energy(MIE) and the Temperature (최소발화에너지와 온도의 관계)

  • 하동명
    • Fire Science and Engineering
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    • v.11 no.2
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    • pp.3-10
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    • 1997
  • Attempts are being made to investigate temperatures dependence of minimum ignition energy (MIE) based on concept of quantity of heat and thermal ignition theory. Regression equations for predicting MIE by means of temperature variations on the basis of statistical and mathematical methods are proposed. This study is undertaken to learn what proposed method is satisfactory hydrocarbons(propane and pentane). The proposed method has been tested and compared sucessfully with previously reported data in various journal.

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A Study on Pressure Dependence of Minimum Ignition Energy (최소발화에너지의 압력의존성에 관한 연구)

  • Ha Dong-Myeong;Lee Su-Kyung
    • Journal of the Korean Institute of Gas
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    • v.1 no.1
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    • pp.7-13
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    • 1997
  • To investigate the pressure dependence of minimum ignition energy(MIE), thermal ignition theory, concept of heat transfer, ideal gas law, and kinetic theory are discussed. Correlation equations for the MIE and pressure were obtained through a regression analysis of reported data. In the proposed methodology the predicted MIE with pressure variations agree with reported data within a few average absolute deviations(A.A.D.). Therefore the proposed methodology has provided to be the general method for predicting the MIE of hydrocarbons.

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A Study on the Minimum Ignition Energy Measurements for Liquid Jet A1 Fuel under at Elevated Oxygen Concentrations and Reduced Atmospheric Pressures (고산소-저기압 환경에서 JET A1 액체연료의 최소점화에너지 측정에 관한 연구)

  • Kwon, Haeng-Jun;Park, Seul-Hyun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.3
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    • pp.88-93
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    • 2017
  • In the present study, the ignition characteristics of liquid fuel were experimentally investigated. To quantify its ignitability as ignition characteristics, the minimum ignition energy (MIE) of liquid fuel was defined and measured under at the elevated oxygen concentrations and reduced atmospheric pressures which that are the most probable conditions likely to be encountered during operation of the space launch vehicle's operating process. The experimental results demonstrate that the measured MIE decreased with the increasing the oxygen concentration at given atmospheric pressures. When the atmospheric pressure was reduced from 1 atm to 0.2 atm at a fixed oxygen concentration, the measured MIE was found to vary with $P^{-2}$ but the lowest MIE was observed at 0.8 atm.

Influence of Electrostatic Discharge Circuit Parameters on the Minimum Ignition Energy of Suspended Dust Clouds (분진운의 최소점화에너지에 대한 정전기 방전회로의 매개변수 영향)

  • Moon, Kyoon-Tae;Chung, Jae-Hee;Yamaguma, Mizuki;Choi, Kwang-Seok
    • Journal of the Korean Society of Safety
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    • v.25 no.5
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    • pp.22-26
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    • 2010
  • The ignitability(minimum ignition energy, MIE) of a suspended dust clouds is very important aspect of technical safety indices. This paper reported the experimental results dealing with the influence of discharge circuit on the MIE of a suspended dust clouds. The movement of a suspended dust clouds was also observed with the high speed camera. The Hartmann vertical-tube apparatus(MIKE-3) described in the international standard of IEC and Polypropylene (PP, 50% volume-average, D50: $761{\mu}m$) resin powders were used in this experiment. The following results were obtained: (1) the MIE of a suspended PP powder depended markedly on the discharge circuit; in other words, when a resistor was connected in series with the discharge sparking circuit(RC), the lowest value(31mJ) of MIE was obtained for a suspended PP powder comparison with the other circuits(C circuit; 370mJ or LC circuit; 71mJ). (2) the discharge duration time is more important than other factors with regard to MIE of a suspended PP powder.

Pyrolysis Characteristic and Ignition Energy of High-Density Polyethylene Powder (고밀도 폴리에틸렌 분진의 열분해성과 착화에너지)

  • Han, Ou-Sup;Lee, Jung-Suk
    • Journal of the Korean Institute of Gas
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    • v.18 no.3
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    • pp.31-37
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    • 2014
  • The aim of this work is to provide new experimental data on the pyrolysis characteristics and the minimum ignition energy (MIE) by using the same high-density polyethylene (HDPE) powder in domestic HDPE dust explosion accident. To evaluate the explosion sensitivity of HDPE, thermo-gravimetric analysis (TGA), differential scanning calorimeter (DSC) and MIE apparatus (MIKE-3, K$\ddot{u}$hner) was conducted. The measurements showed the volume median diameter of $61.6{\mu}m$ but the particle number density of 98 % in the range $0.4{\sim}4{\mu}m$. The ignition temperature from the results of TGA and DSC in HDPE dust layers was observed in the range of $380{\sim}490^{\circ}C$. MIE was measured under 1 mJ in the HDPE dust concentration of $1200{\sim}1800g/m^3$, it was found that the ratio of particle number density in the range $0.4{\sim}4{\mu}m$ was very high (98%).

Electrostatic Discharge and the Minimum Ignition Energy Measurement of Three-Component Flammable Gas Mixtures (정전기(靜電氣) 방전(放電)과 삼성분계(三成分系) 가연성(可燃性) 혼합기체(混合氣體)의 최소점화(最小點火) Energy 측정(測定)에 관한 연구(硏究))

  • Lee, Gwan-Hyung;Choi, Sang-Won;Chung, Jae-Hee;Lee, Duck-Chool
    • Proceedings of the KIEE Conference
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    • 1997.07e
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    • pp.1819-1823
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    • 1997
  • When flammable gases are mixed with air or oxygen in the explosion concentration range and are ignited by sufficiently large electrostatic discharge energy, they may explode causing severe disaster in workplaces. The minimum ignition energy (MIE) of single gas-air mixtures has been already investigated by many researchers, but the MIE of mixtures of more than three substances is not examined yet. The purpose of this study is to investigate the MIE of several three-component gas mixtures experimentally. The result of our experiment shows that the MIE of some gas mixtures is quite different from that we expected based on the characteristics of individual gas-air mixture.

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Characteristics of Dust Explosion in Dioctyl Terephthalic Acid Manufacturing Process (디옥틸테레프탈산 제조공정에서 분진폭발 특성에 관한 연구)

  • Lee, Chang Jin;Kim, Lae Hyun
    • Korean Chemical Engineering Research
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    • v.57 no.6
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    • pp.790-803
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    • 2019
  • The dioctyl terephthalic acid (DOTP) process produces plastic plasticizers by esterification of terephthalic acid with powder in the form of octanol. In this study, the dust explosion characteristics of terephthalic acid directly injected into the manhole in the form of powder in the presence of flammable solvent or vapor in the reactor of this process were investigated. Dust particle size and particle size distribution dust characteristics were investigated, and pyrolysis characteristics of dust were investigated to estimate fire and explosion characteristics and ignition temperature. Also, the minimum ignition energy experiment was performed to evaluate the explosion sensitivity. As a result, the average particle size of terephthalic acid powder was $143.433{\mu}m$. From the thermal analysis carried out under these particle size and particle size distribution conditions, the ignition temperature of the dust was about $253^{\circ}C$. The lower explosive limit (LEL) of the terephthalic acid was determined to be $50g/m^3$. The minimum ignition energy (MIE) for explosion sensitivity is (10 < MIE < 300) mJ, and the estimated minimum ignition energy (Es) based on the ignition probability is 210 mJ. The maximum explosion pressure ($P_{max}$) and the maximum explosion pressure rise rate $({\frac{dP}{dt}})_{max}$ of terephthalic acid dust were 7.1 bar and 511 bar/s, respectively. The dust explosion index (Kst) was 139 mbar/s, corresponding to the dust explosion grade St 1.