• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.3
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• pp.474-478
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• 2018

The use of metals such as aluminum and titanium and the related industrial facilities have been continuously increasing to meet the requirements of the improvement of high-tech products due to the development of industry, and explosion of metal dust. Semiconductor process Metal dust is essential, but research is insufficient. The purpose of this study is to identify risk by analyzing the quantitative risk such as maximum explosion pressure and minimum explosion concentration applied international test standard in order to select the semiconductor process facilities handling dust and to predict possible risk of accidents.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.47-52
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• 2005

The wide use of metal dusts have been found in industrial field and many dust explosion accidents occur by fire spread of dust layer. In this study, we developed a new experimental device to examine fire and explosion characteristics of the dust layer. Aspects of the burning zone over metals(Mg, Zr, Ta, Ti, etc) and PMMA(Polymethyl methacrylate) dust layers have been investigated experimentally to clarify behaviors (Spread rate and quenching distance) and effects of $N_2$ surrounding gas on the fire spread over metal dust layers. From the experimental result, it was found that the spread rate of metal dusts is larger than PMMA, the dependability of spread rate over the thickness of dust layer is small, and the minimum oxygen concentration of spread flame over Mg dust layer is 3.6-3.7 vol%. Since high correlation between the spread rate and the reciprocal of quenching distance was seen, relative risk prediction in those inflammable parameters can be predicted.

• Journal of the Korean Society of Safety
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• v.39 no.2
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• pp.38-43
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• 2024

Recently, with the expanding market for electronic devices and electric vehicles, secondary battery usage has been on the rise. Lithium-ion batteries are particularly popular due to their fast charging times and lightweight nature compared to other types of batteries. A secondary battery consists of four components: anode, cathode, electrolyte, and separator. Generally, the positive and negative electrode materials of secondary batteries are composed of an active material, a binder, and a conductive material. Acetylene Black (AB) is utilized to enhance conductivity between active material particles or metal dust collectors, preventing the binder from acting as an insulator. However, when recycling waste batteries that have been subject to high usage, there is a risk of fire and explosion accidents, as accurately identifying the characteristics of Acetylene Black dust proves to be challenging. In this study, the lower explosion limit for Acetylene Black dust with an average particle size of 0.042 ㎛ was determined to be 153.64 mg/L using a Hartmann-type dust explosion device. Notably, the dust did not explode at values below 168 mg, rendering the lower explosion limit calculation unfeasible. Analysis of explosion delay times with varying electrode gaps revealed the shortest delay time at 3 mm, with a noticeable increase in delay times for gaps of 4 mm or greater. The findings offer fundamental data for fire and explosion prevention measures in Acetylene Black waste recycling processes via a predictive model for lower explosion limits and ignition delay time.

• Journal of the Korean Institute of Gas
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• v.21 no.4
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• pp.84-91
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• 2017

Recent years have witnessed the increased usage of flammable metals, such as aluminum or magnesium, in wide range of high-tech industries. These metals are indispensable for the improvement of physical properties of materials as well as the design capability of the final product. During the process, unwanted metal dusts could be released to the environment. This can lead to an occupational health and safety issues. Due to their flammable nature, more serious problem of an explosion can happen in extreme cases. The explosion is the combustion of tiny solid particles and vapor mixture, caused by pyrolysis. This complex composition makes engineering analysis more difficult, compared to simple gas explosions or vapor cloud combustions. The study was conducted to assess this light metal dust explosion in an effort to provide the bases for a risk assessment. Dust explosion characteristics of each material was carefully evaluated and an appropriate analysis tool was developed. A comprehensive database was also constructed and utilized for the calibration of the developed response model and the verification for its accuracy. Subsequently, guidelines were provided to prevent dust explosions that could occur in top-notch industrial processes.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.19-24
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• 2011

Due to the latest industrial flow comes mainly switch to high-tech industries, combustible metals as Al, Mg, Li, Zn more require to use for the aircraft, car, cell phones, electronics and others. As a result, Increasing the processing of combustible metals due to increase in amount of combustible metals giving rise dust explosions also. Most Explosions caused by combustible metal dust, occurred in air cleaning device of local exhaust ventilation to capture and store the combustible dust. Therefore, this study was conducted to present and analyze technically that deformation and rupture shape of air cleaning device structure by Finite Element Analysis(FEA) rather than a simple prediction, in case of explosion occurs in an air cleaning device.

• Journal of the Korean Institute of Gas
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• v.16 no.4
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• pp.32-37
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• 2012

The aim of this study is to evaluate the characteristics of explosion and flame velocity that can be utilized to factories where Mg-Al alloy metal powders are handled in the form of raw materials, products or by-product for similar dust explosion prevention and mitigation. Because the strength of the blast pressure is the result due to flame propagation, flame velocity in dust explosion can be utilized as a valuable information for damage prediction. An experimental investigation was carried out on the influences of content ratio of Mg-Al alloy (mean particle size distribution of 151 to 161 ${\mu}m$). And a model of flame propagation velocity based on the time to peak pressure and flame arrival time in dust explosion pressure, assuming the constant burning velocity, leads to a representation of flame velocity during dust explosion. As the results, the maximum flame velocity of Mg-Al(60:40 wt%), Mg-Al(50:50 wt%) and Mg-Al(40:60 wt%) was estimated 15.5, 18 and 15.2 m/s respectively, and also tend to change with content ratio of Mg-Al.

• Journal of the Korean Institute of Gas
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• v.16 no.6
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• pp.1-6
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• 2012

Using the Siwek 20 L spherical explosion vessel, the explosion properties have been examined to understand the influence of magnesium content in Mg-Al alloy dusts with different concentration. For this purpose, the Mg-Al alloy dusts (volume mean diameter : $151{\sim}160{\mu}m$) with magnesium content ratio were used. As the results, the increase of Mg content in Mg-Al alloy causes an decreased minimum explosion concentration and an increased maximum explosion pressure. Also the maximum explosion pressure and maximum rate of pressure rise in Mg-Al alloy dusts mainly depended on the dust concentrations. However, for the explosion index (Kst) of Mg-Al (40:60 wt%), Mg-Al (50:50 wt%) and Mg-Al (60:40 wt%), it was founded to increase the Kst with increasing of magnesium content ratio.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.7-13
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• 2012

An experimental study has been done to investigate the explosion characteristics of aluminum powders with different sizes and concentrations in a 20 L spherical explosion vessel. Two different sizes of aluminum powder were used : $15.1{\mu}m$ and $34.8{\mu}m$ with a volume mean diameter. The results revealed that $15.1{\mu}m$ Al powder has a Lower explosion limit (LEL) of $40g/m^3$, a maximun explosion pressure ($P_{max}$) of 9.8 bar and a maximum rate of pressure rise ($[dP/dt]_{max}$) of 1852 bar/s, in $34.8{\mu}m$ Al powder, LEL of $70g/m^3$, $P_{max}$ of 7.9 bar and $[dP/dt]_{max}$ of 322 bar/s. The LEL of Al powders tended to increase with the increase of particle size. Also, it was found that the flame velocity calculated from the powder with $15.1{\mu}m$ was about 5 times higher than that of the powder of $34.8{\mu}m$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.425-429
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• 2011

The development of metal plasma generated by high laser irradiance and its effect on the surrounding air using shadowgraph images after laser pulse termination are studied; hence the formation of laser supported detonation and combustion processes has been investigated. The core of the paper is in detecting chemical reaction using X-Ray Diffraction (XRD) between ablated aluminum plasma and oxygen from air by inducing high power laser pulse (>1000 mJ/pulse) and conduct a quantitative comparison of chemically reactive laser initiated waves with the classical detonation of exploding aluminum (dust) cloud in air. This study may suggest a new approach of initiating detonation from metal sample in its bulk form without the need of mixing nano-particles with oxygen for initiation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.2
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• pp.197-204
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• 2012

We explore the evolution of metal plasma generated by high laser irradiances and its effect on the surrounding air by using shadowgraph images after laser pulse termination and X-ray diffraction (XRD) of aluminum plasma ablated by a high-power laser pulse (>1000 mJ/pulse) and oxygen from air. Hence, the formation of laser-supported detonation and combustion processes has been investigated. The essence of this paper is in observing the initiation of chemical reaction between the ablated aluminum plasma and oxygen from air by the high-power laser pulse (>1000 mJ/pulse) and in conducting a quantitative comparison of the chemically reactive laser-initiated waves with the classical detonation of an exploding aluminum (dust) cloud in air. The findings in this work may lead to a new method of initiating detonation from a metal sample in its bulk form without any need to mix nanoparticles with oxygen for initiation.