Korean Chemical Engineering Research

The Korean Institute of Chemical Engineers (한국화학공학회)
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Hazard Evaluation of Minimum Ignition Energy by Electrostatic Voltage in Suspended Dust Particles

부유 분진의 정전압에 의한 최소착화에너지 위험성평가

  • Han, Oue-Sup (Occupational Safety & Health Research Institute)
  • 한우섭 (한국산업안전보건공단 산업안전보건연구원)
  • Received : 2021.05.20
  • Accepted : 2021.06.21
  • Published : 2021.08.01
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Abstract

We investigated experimentally the ignition characteristic of dust and the hazard evaluating for electrostatic discharge. The ignition energy experiments were performed on sample dusts such as PE(HD), PE(LD), PMMA using the MIKE-3 apparatus. The formation of flame during the ignition of PE(HD) dust clouds occurred after the delay time of about 8 ms, and the flame kernels were not observed in center of ignition occurrence area. The voltage increased with increasing the number of dust dispersions and the increase rate of measured voltage with dust concentration was the highest in the order of PMMA, PE(LD) and PE(HD). For the effect of dispersion condition on the voltage in PE(HD) dust, the results were obtained that the voltage increased as the number of dispersions increased and as the concentration increased under the same dispersion number. The safety voltages to prevent fire and explosions by electrostatic ignition were estimated that PE(HD), PE(LD)-1, PE(LD)-2, and PMMA were 2.58, 44.72, 25.82, and 8.16 kV, respectively. We proposed the method for estimating the minimum ignition energy by using the measured voltage data for efficient investigation of electrostatic ignition hazard.

본 연구에서는 분진의 착화 특성 및 정전기 위험성 평가법을 실험적으로 조사하였다. 착화에너지 시험은 PE(HD), PE(LD), PMMA 분진에 대해 MIKE-3장치를 사용하여 실시하였다. PE (HD)의 경우 약 8 ms의 일정 시간 경과 후에 분진운의 착화 화염이 형성되고, 착화원 중심부에서는 화염 핵이 관찰되지 않았다. 분진의 분산 횟수가 증가함에 따라 정전압이 증가하고 분진 농도에 따른 정전압 발생 증가율은 PMMA, PE(LD), PE (HD) 순으로 가장 높았다. PE(HD) 분진의 분산 조건이 정전압에 미치는 영향을 조사하였으며, 분산 횟수가 많아질수록 정전압이 증가하였고 동일한 분산 횟수에서는 분진 농도가 높아질수록 정전압이 증가하였다. 정전기 착화에 의한 화재폭발사고 예방을 위한 안전 정전압은 PE(HD), PE(LD)-1, PE(LD)-2, PMMA에 있어서 각각 2.58, 44.72, 25.82, 8.16 kV로 추정되었다. 정전압 측정자료를 사용하여 정전기 착화 위험성을 효율적으로 조사하여 최소착화에너지를 추정하는 방법을 제안하였다.

Keywords

References

  1. Database for Major industrial accidents, Korea Occupational Safety and Health Agency (1988~2020).
  2. Han, O.S., "Study on Reduction of Dust Fire and Explosion Acidents by Electrostatic Discharge," KOSHA, 2019-OSHRI-1641, 23-28 (2019).
  3. Jonassen, N. M., "Explosions and Static Electricity in Electrical Overstress," Electrostatic Discharge Symposium Proceedings, 331-337(1995).
  4. Juliusz, B. Gajewski, "Monitoring of Electrostatic Fire and Explosion Hazards at the Inlet to Electrostatic Precipitators," J. Electrostatics, 72, 192-197(2014). https://doi.org/10.1016/j.elstat.2014.02.003
  5. Yamaguma, M. and Kodama, T., "Observation of Propagating Brush Discharge on Insulating Film with Grounded Antistatic Materials," IEEE Trans. on Insdutry Applications, 40, 451-456 (2004). https://doi.org/10.1109/TIA.2004.824512
  6. Ohsawa, A. and Ichikawa, N., "ESD Detection by Transient Earth Voltage," Journal of Physics, 418, 1-6(2013).
  7. Olsen, W., Arntzen, B. J. and Eckhoff, R. K., "Electrostatic Dust Explosion Hazards - towards a < 1 mJ Synchronized-spark Generator for Determination of MIEs of Ignition Sensitive Transient Dust Clouds," Journal of Electrostatics, 74, 66-72(2015). https://doi.org/10.1016/j.elstat.2014.12.006
  8. EN 13821, "Potentially Explosive Atmospheres - Explosion Prevention and Protection-Determination of minimum ignition energy of dust/air mixtures," (2002).
  9. ASTM, "Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air," E 2019-03. West Conshohocken, PA: ASTM International (2007).
  10. IEC 61241-2-3, "Electrical Apparatus for use in the Presence of Combustible Dust - Part 2: Test Methods - Section 3: Method for Determining Minimum Ignition Energy of Dust/air Mixtures," (1994).
  11. Gan, B., Gao, W., Jianga, H., Li, Y., Zhang, Q. and Bi, M., "Flame Propagation Behaviors and Temperature Characteristics in Polyethylene Dust Explosions," J. Powder Technology, 328, 345-357 (2018). https://doi.org/10.1016/j.powtec.2018.01.061
  12. Nifuku, M. and Katoh, H., "Incendiary Characteristics of Electrostatic Discharge for Dust and Gas Explosion," J. Loss Prev. in the Process Ind., 14, 547-551(2001). https://doi.org/10.1016/S0950-4230(01)00046-8