• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.29-34
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• 2021

Flammable substances are often present in the raw materials of pharmaceutical products manufactured by pharmaceutical companies. In this case, an excessive amount of flammable substances is added to make an intermediate, and flammable substances that do not participate in the reaction are removed through filtration and drying steps. In addition, the flammable liquid separated in the filtration process is accumulated in the form of splash filling in the filtrate container. In this case, vapor and mist of flammable liquid are generated, which lowers the lower limit of explosion and minimum ignition energy, and increases the risk of fire and explosion due to complex charging. In this study, by analyzing fire accidents that occurred during the recent filtration process of pharmaceutical companies, it is proposed to prevent static electricity accumulation by measures of nitrogen supply facilities, capacity improvement, conductive filter fabric and so on.

• 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.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.565-570
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• 2007

The explosionproof apparatus is a devices that is enclosed in a case capable of withstanding an explosion of a specified gas or vapor that may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and that operates at such an external temperature that a surrounding flammable atmosphere will not be ignited thereby This kind of exeplosionfproof devices should be installed suitable for the characteristics of the space or process condition that should be protected to prevent explosion or fire. But, due to the lack of information and techniques on the explosionproof technology, some dangerous area is not properly protected from an explosion or it cost too much to implement the explosionproof devices. In this report, the basic guidelines and several case studies of explosionproof devices installation will be introduced to be of help to field safety engineer.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.76-82
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• 1994

Combustion phenomena(characteristics) of organic solvents including various alcohols Immobilized on ceramic balls were studied. Experiments were performed by burning methyl, ethyl, and propyl alcohol immobilized on sands (particle size 0.35mm) and coramic balls(particle size 1~5mm) to measure mass burning rate, height burning rate and combustion temperature. The longer time from ignition to extinguishment was resualted from the larger particle size of ceramic balls and the smaller size of ceramic balls exhibited the higher mass burning rate. Of alcohols tested the relative magnitude of facilitation of combustion was methyl >ethyl >propyl. Combustion temperatare of alcohols, without regard to the types of alcohols, was not increased with smaller ceramic balls(up to 3mm of particle size). However, with larger ceramic balls, combustion temperatare of alcohols was increased by 40~5$0^{\circ}C$ and the highest combustion temperatare was obtained with sands(particle size 0.35mm). Also, second rising was occurred at the combustion time of I5-20min. and this second rising time was increased with the smaller particle. These results will be able to be used for petrochemical industries using particles to evaluate the danger of fire and explosion.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.5
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• pp.86-96
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• 2007

A direct-injection stratified-charge(DISC) engine has been considered as a promising alternative in spite of high unburned hydrocarbon emission levels during light load operation. In this paper investigation is made to characterize formation and combustion processes of stratified mixture charge in a simple constant volume combustion chamber. Both experimental and numerical analyses are performed for fluid and combustion characteristics with 3 different induction types for rich, homogeneous and lean mixture conditions. The commercial code FIRE is applied to the turbulent combustion process in terms of measured and calculated pressure traces and calculated distributions of mean temperature, OH radical and reaction rate. It turns out that the highest combustion rate occurs for the rich state condition at the spark ignition location due to existence of stoichiometric mixture and timing.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.580-584
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• 2012

The insulating oils perform a cooling and insulation action in electric power transformer. The mineral oil has immanent fire dangerousness and environmental contamination problem. Vegetable insulating oil has higher ignition point, flash point and more excellent biodegradability than conventional mineral oil. In a real oil-filled transformers, some of the power is dissipated in the form of heat. And transformer require the heat to be removed from the winding and insulator by forced convection of the insulating oil. The flow electrification occurs when insulating oil was forced to be circulated. In this paper, influence of temperature, velocity of flow, and insulating pipe and diameter on streaming electrification of vegetable insulating oil was investigated using forced circulation apparatus. Temperature effects were most significant, and it showed a peak in the temperature $30^{\circ}C$ to $35^{\circ}C$ at insulating and copper pipe. The change of flow electrification according to area variety could be checked by change of diameter.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.21-27
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• 2017

Even if several chemical accident prevention systems such as PSM(Process Safety Management), RMP(Risk Management Plan), etc. have been carried out, many chemical accidents have still occurred at industrial plants in Korea. We describe the status of chemical industry and the trend of occurrence of chemical accidents in Korea. And this paper analyzes the recent chemical accidents in eight ways. These ways include chemical accident forms, ignition sources, sources of chemical equipment, human vs equipment/material causes, worker's working situation, employee scale, hazardous substances, week & time, fatalities of manufacture & contractor's workers. Finally we proposes the four representative prevention measures brought to result of cause analysis by accident statistics.

• Journal of the Korean Society of Safety
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• v.25 no.4
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• pp.30-35
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• 2010

For the safe handling of acetone, the flash point, the explosion limit at $25^{\circ}C$ and the temperature dependence of the explosion limits were investigated. And the AIT for acetone were experimented. By using the literatures data, the lower and upper explosion limits of acetone recommended 2.5 vol% and 13.0 vol%, respectively. In this study, the lower flash points of acetone recommended $-20^{\circ}C$. This study was determined relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for acetone, and the experimental AIT of acetone was $565^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of acetone is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.184-186
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• 2009

In past, transformer connection study was concentrated on efficiency improvement and life time broadening. But environmental side began to become important recently. In existing, quick transaction of mineral oil used to insulation oil of transformer is possibility to be difficult and causes environmental pollution in case of was outpoured and there is worry of fire occurrence. Accordingly, nonflammable performance becomes many interest in excellent vegetable oil because ignition point is high than mineral oil and environment friendly material. But, vegetable oil is cooling of transformer and insulation problem of insulating paper for cause of insulation oil special quality. Therefore, in this paper, special quality of vegetable oil that there are being a lot of mineral oil and the latest interest examined about problem and consideration item to be solved to analyzed comparison and applies vegetable oil to transformer for electric power.

• 연구논문집
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• s.29
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• pp.29-38
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• 1999

In comparison with gasoline engine, LPG direct injection engine has some advantages not only in emission and fuel efficiency but also in prevention of power decrease and back fire etc. which are disadvantages of conventional LPG engine. In this study, comparision tests of the incylinder spray and combustion characteristics between of LPG and gasoline fuels were performed in the RCEM as a basic research for the development of future LPG engine with low emission and high fuel efficiency During the direct injection of LPG fuel and gasoline into the inside of RCEM, spray development characteristics according to the injection condition have been photographed by the high speed shadow graph methods. The conditions for the optimum mixture distribution of LPG and gasoline fuels are achievable at the selected ignition timing, respectively.