• Journal of the Korean Institute of Gas
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• v.15 no.4
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• pp.27-32
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• 2011

Management of gas safety is becoming important with increasing use of gas facilities. U-safety system is being promoted as part of national management of gas, and thus real-time and in-situ gas sensor should be developed. Detection method for When the gas sensor is installed in gas conduit, explosion may be likely, because hydrocarbon gases is usually used the difference of thermal resistance between reference and working electrode. Therefore, it is required to detect the hydrocarbons, such as $CH_4$ and CO, at room temperature via electrochemically catalytic reaction. In this study, Pt nanoparticle was doped on the porous gold powder by electrolytic plating method, and then it was used as catalytic electrode for CO oxidation. For Pt/PAu electrode, approximately 21% of CO conversion was obtained. It is noted that Pt/PAu electrode could be used to react the oxidation of hydrocarbon gases at room temperature via applying of external voltage.

• Journal of Energy Engineering
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• v.26 no.4
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• pp.7-13
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• 2017

As environmental problems become a problem of survival, interest in eco-friendly energy is increasing to improve the environment. So, demand for eco-friendly fuels such as hydrogen, LPG and CNG is increasing. In particular, Korea, which relies on imports of most fuels, is investing in the development of hydrogen energy, which is favorable in terms of high production volume and energy independence. However, As demand grows every year, a variety of accidents occur in various ways, ranging from small leak incidents to massive fires and explosion, thus research needs to be done. So, in this study, compared and analyzed cases of hydrogen, LPG, CNG accidents occurring at domestic and overseas refueling stations. and various programs were used for assessing risk, estimated the flame length due to gas leakage and evaluated the dangerous distance.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.33-40
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• 2016

Liquid fuel can be easily exploded and release more energy of detonation than conventional explosives because it has different explosion mechanism. In order to analyze dispersion characteristics of liquid fuel for the safety purpose, two tests are conducted. First, pre-test, which is a computer simulation, is carried out by a software called ANSYS AUTODYN to eliminate the effect of a canister that usually causes irregular dispersion of the fuel. Second, field test is performed to find out the amount and density effect of bursting charge. High speed cameras are installed in front of the canister to visualize the mechanism. Velocity, area and radius of the dispersed cloud are measured by image processing software, these are shown that the amount of bursting charge affects cloud velocity and area but density is not a significant factor of cloud formation.

• Journal of the Korean Society of Safety
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• v.17 no.4
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• pp.126-132
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• 2002

By using the reference data, the empirical equations which describe the interrelationships of explosion properties and physical properties of n-chlorinated hydrocarbons have been derived. The properties which have been correlated are the lower and upper explosive limits, the stoichiometric coefficients, the heats of combustion, the carbon numbers. Also, the new equations using the mathematical and statistical methods for predicting the temperature dependence of lower explosive limits(LEL) of chlorinated hydrocarbons on the basis of the literature data are proposed. The fire and explosion properties calculated by the proposed equations in this research were a good agrement with literature data within a few A.A.P.E.(Average Absolute Percent Error) and A.A.D.(Average Absolute Deviation.) From a given explosive properties, by using the proposed equations, it is possible to predict to the fire and explosion characteristics for the other chlorinated hydrocarbons.

• Journal of the Korean Society of Safety
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• v.15 no.3
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• pp.71-77
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• 2000

The aim of this study is to investigate the temperature dependence of the lower explosive limit(LEL) at elevated temperature. The temperature dependence of the lower explosive limit is one of the significant indices of flammability and combustibility. By using the literature data, the new equations for predicting the temperature dependence of the lower explosive limits for paraffinic hydrocarbons are proposed. The values calculated by the proposed equations were a good agreement with the literature data. It is hoped eventually that this proposed equations will support the use of the prediction for the lower explosive limit and the flash points of the flammable mixtures.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.59-64
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• 2011

Explosion limit and flash point are the major combustion properties used to determine the fire and explosion hazards of the flammable substances. In this study, in order to predict upper explosion limits(UELs), the upper flash point of n-alkanes and aromatic compounds were measured under the VLE(vapor-liquid equilibrium) state by using Setaflash closed cup tester(ASTM D3278). The UELs calculated by Antoine equation and chemical stoichiometric coefficient tusing the experimental upper flash point were compared with the several reported UELs. From the given results, using the proposed experimental and predicted method, it is possible to research the upper explosion limits of the other flammable substances.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.89-101
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• 2015

The sour gas is natural gas containing components such as hydrogen sulphide and carbon dioxide that form acids when mixed with water. Element sulfur precipitates from sour gas when reservoir pressure and temperature decrease. According to the International Energy Agency, about 43% of the world's natural gas reserves(2,580 tcf or 73.057 tcm), excluding North America, are sour. The sour gas is often derived from the Germanic word 'sauer or acidic' and the etymology referred to as 'sour'. Sour gas requires special handling and infrastructure because it contains significant amounts of hydrogen sulphide, making it highly corrosive, flammable and explosive, and there fore more costly and dangerous to process. So the business of sour gas is affected by two important factors: the economic value of the gas, and the methods used in its production. According to be analyzed in the academic literature to sour gas(2000~2014) by the program of 'web of science', the research activities 145 papers in sour gas.

• Korean Chemical Engineering Research
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• v.47 no.5
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• pp.572-579
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• 2009

This study is to investigate experimentally the flame structure and propagation mechanism in dust explosions and to provide the fundamental knowledge. Upward propagating laminar dust flames in a vertical duct of 1.8 m height and 0.15 m square cross-section are observed and flame front is visualized using by a high-speed video camera. Also, the thicknesses of preheated and reaction zone have been determined by a schlieren, electrostatic probe and thermocouple. The thickness of preheated zone in lycopodium dust flame is observed to be 4~13 mm, about several orders of magnitude higher than that of premixed gaseous flames. From the experimental results by a PIV(Particle Image Velocimetry) system, a certain residence time of the unburned particle in preheated zone is needed to generate combustible gas from the particle. The residence time will depend on preheated zone thickness, particle velocity and flame propagation velocity.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.428-428
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• 2016

Copper indium sulfide (selenide) (CuIn(S,Se)2,CISSe)는 1.0~1.5 eV의 Direct band gap과 105 cm-1이 넘는 큰 광 흡수 계수를 가지고 있어 박막 태양전지의 흡수층으로써 연구되어 왔다. 최근 대량생산 및 저가 공정에 용이하다는 측면에서 용액 공정 기반 CISSe 태양전지 연구가 크게 주목 받고 있다. 용액공정 기반 중 하이드라진을 사용 한 경우 매우 높은 효율을 기록하였으나, 하이드라진 자체의 유독성과 폭발성 때문에 분위기 제어가 필요하고 여전히 저가화 및 대면적 제작에 한계가 있다. 따라서 알코올 솔젤 기반 CISSe 태양전지 제작 연구가 많이 진행되었으나, 결정립 성장 및 칼코겐 원자를 공급하기 위해 불가피하게 황화/셀렌화 후속 열처리 공정을 요구한다. 후속 열처리 공정은 폭발성의 황화수소/황화셀레늄 기체 분위기 제어와 고가의 장비를 필요로 한다. 본 연구에서는 매우 안정적이며 저가 용매인 물과 아민계 첨가제를 이용하여 Cu, In 전구체와 S, Se 이 포함된 Cu-In-S 잉크와 Se잉크를 제작하였다. 잉크 내에 S, Se을 첨가 함으로써 추가적인 후속공정 없이 비활성 가스 분위기에서 고품질의 CISSe 박막 제작을 가능케 하였다. 또한 Se 잉크 증착 횟수에 따른 결정 구조, 광학적 성질의 차이에 주목하였다. 따라서 수계 잉크를 대기 중에서 스핀코팅으로 박막을 제작한 후, Hot plate에서 건조하여 균일한 박막을 제조하고, 제작된 박막을 tube furnace에서 환원 분위기 및 비활성 가스 분위기에서 열처리 진행하여 $1.3{\mu}m$ 두께의 고품질의 CISSe 흡수층을 제작하였다. 이러한 흡수층에 대해 XRD, SEM, EDS 분석을 진행하여, 결정성, 미세구조, 및 조성을 확인하였으며, 제작된 흡수층 위에 버퍼층/투명전극층을 차례로 증착하여 CISSe 태양전지를 제작하여 셀 성능 및 양자 효율 특성을 파악하였다. 또한 액상 Raman 분석을 통해 결정립 성장 과정 메커니즘을 제시하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1297-1303
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• 2015

The internal chromium plating of a long-axis tube is widely used in military and industrial application, with the thick hard plating formed using a mixed solution of Chromium acid and catalytic $H_2SO_4$. A large-caliber gun can endure a high explosive force as a result of the increased stiffness and wear resistance provided by this internal hard chromium surface. The internal chromium layer of a tube is prone to exfoliation caused by the high kinetic energy of the projectile and high pressure of the explosion. Therefore, we reviewed the plating process. Chromium plating comprises many steps, including the removal of Grease, water cleaning, electrolytic abrasion, etching, plating, water cleaning, and hydrogen brittleness removal. The exfoliated chromium plating layer is affected by the adhesion property of the plating. In particular, the Fe concentration of the electrolyte affects the adhesion property. The optimum Fe concentration for effectively suppressing the exfoliation of the plating layer was established by using a scanning electron microscope to determine the surface roughness, and the effectiveness was proved in an adhesion test, etc.