• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.85-90
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• 2014

For the safe handling of acetic anhydride, this study was investigated the explosion limits of acetic anhydride in the reference data. And the lower flash points, upper flash points, and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower and upper explosion limits of acetic anhydride by the investigation of the literatures recommended 2.9 Vol% and 10.3 Vol.%, respectively. The lower flash point of acetic anhydride by using Setaflash closed-cup tester was experimented $49^{\circ}C$. The lower flash point acetic anhydride by using Tag and Cleveland open cup tester were experimented $55^{\circ}C$and $62^{\circ}C$, respectively. Also, this study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for acetic anhydride. The experimental AIT of acetic anhydride was $350^{\circ}C$.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2003.10a
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• pp.154-159
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• 2003

화학공장과 제조업 등의 사업장에서 발생하는 화재 및 폭발은 설비와 건물의 파괴뿐만 아니라 사업장의 근로자와 인근 주민에 대한 인명 피해까지 초래하는 경우가 많으므로 공정 안전을 위해 화재 및 폭발 분야의 연구에 많은 관심을 가져야 한다. 방화(Fire Protection) 및 방폭(Fire Protection)에 관련되는 특성치로 MSDS의 5번째 항목인 폭발화재시대처방법(Fire-fighting Measures)에서는 폭발(연소)한계(Explosive Limit 혹은 Flammability Limit), 인화점(Flash Point), 최소발화온도(AIT： Auto-ignition Temperature)가 제시되고 있다.(중략)

• Journal of the Korean Society of Safety
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• v.19 no.3 s.67
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• pp.65-69
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• 2004

This study was performed with Hartmann type dust explosion apparatus and Godbert-Greenwald furnace apparatus in order to research the effect of temperature and humidity affecting LEL, minimum ignition temperature of Hydroxy Propyl Methyl Cellulose. The experimental determinations in the range between $20^{\circ}C\;and\;60^{\circ}C$ of temperature was not affected $LEL(180g/m^3)$ but LEL showed $200g/m^3\;and\;250g/m^3\;at\;80^{|circ}C\;and\;100^{\circ}C$. As the change of humidity LEL was $180g/m^3\;for\;50\%,\;200g/m^3\;for\;60\%\;and\;250g/m^3\;for\;70\%$ but dust explosion didn't occur over $80\%$. The ignition temperature of HPMC dust clouds was increased as increasing of humidity. So, the minimum ignition temperatures at $50\%,\;60\%,\;70\%\;80\%$ of humidity was $363^{\circ}C,\;375^{\circ}C,\;397^{\circ}C,\;405^{\circ}C$.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.58-64
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• 2006

Homogeneous charge compression ignition(HCCI) combustion is an advanced technique for reducing the hazardous nitrogen oxide(NOx) and particulate matter(PM) in a diesel engine. NOx could be reduced by achieving lean homogeneous mixture resulting in combustion temperature. PM could be also reduced by eliminating fuel-rich zones which exist in conventional diesel combustion. However previous researches have reported that power-output of HCCI engine is limited by the high intensive knock and misfiring. In an attempt to extend the upper load limit for HCCI operation, supercharging in combination with Exhaust Gas Recirculation(EGR) has been applied: supercharging to increase the power density and EGR to control the combustion phase. The test was performed in a single cylinder engine operated at 1200 rpm. Boost pressures of 1.1 and 1.2 bar were applied. High EGR rates up to 45% were supplied. Most of fuel was injected at early timing to make homogeneous mixture. Small amount of fuel injection was followed near TDC to assist ignition. Results showed increasing boost pressure resulted in much higher power-output. Optimal EGR rate influenced by longer ignition delay and charge dilution simultaneously was observed.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.335-342
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• 1997

Experiments were conducted to evaluate the hazard risks of vehicle fires. Sensors were strategically placed in passenger cars to determine the temperature, propagation rate and direction of flame. The life safety hazard evaluations such as smoke and gas analysis were included. An important ignition position was performed in the engine compartment. The effects of different ignition positions and the opening of door glasses were also reviewed. The experimental results indicate that the maximum temperature when a vehicle burns varies commonly from 90$0^{\circ}C$ -100$0^{\circ}C$. The flame reaches in the face of a driver about 6-7minutes and the windshield glass breaks about 10 minutes after the ignition in the engine compartment of vehicle. And the smoke and gas concentrations reached the limit of human inhalation after 13-14 minutes. Especially the concentrations of carbon monoxide exceeded the TWA(50 ppm) during short time after ignition in cases of all experiments.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3286-3297
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• 2021

The released hydrogen can be ignited even with weak ignition sources. This emphasizes the importance of the hydrogen flammability evaluation to prevent catastrophic failure in hydrogen related facilities including a nuclear power plant. Historically numerous attempts have been made to determine the flammability limit of hydrogen mixtures including several diluents. However, no analytical model has been developed to accurately predict the limit concentration for mixtures containing radiating gases. In this study, the effect of H₂O and CO₂ on flammability limit was investigated through a numerical simulation of lean limit hydrogen flames. The previous flammability limit model was improved based on the mechanistic investigation, with which the amount of indirect radiation heat loss could be estimated by the optically thin approximation. As a result, the sharp increase in limit concentration by H₂O could be explained by high thermal diffusivity and radiation rate. Despite the high radiation rate, however, CO₂ with the lower thermal diffusivity than the threshold cannot produce a noticeable increase in heat loss and ultimately limit concentration. We concluded that the proposed mechanistic analysis successfully explained the experimental results even including radiating gases. The accuracy of the improved model was verified through several flammability experiments for H₂-air-diluent.

• Journal of the Korean Society of Safety
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• v.24 no.5
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• pp.28-33
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• 2009

The thermochemical parameters for safe handling, storage, transport, operation and process design of flammable substances are explosion limit, flash point, autoignition temperatures(AITs), minimum oxygen concentration(MOC), heat of combustion etc.. Also it is necessary to know explosion limit at high temperature and pressure. For the safe handling of benzene, lower explosion limit(LEL) at $25^{\circ}C$, the temperature dependence of the explosion limits and flash point were investigated. And the AITs for benzene were experimented. By using the literatures data, the lower and upper explosion limits of benzene recommended 1.3 vol% and 8.0 vol%, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for benzene, and the experimental AIT of benzene was $583^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of benzene is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.1-9
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• 2005

An experimental study was carried out to obtain the fundamental data about the effects of radical ignition on premixture combustion. A CVC(constant volume combustor) divided into the sub-chamber and the main chamber was used. Numerous narrow passage holes are arranged between the main chamber and the sub-chamber. The products including radicals generated by spark ignition in tile sub-chamber derives the simultaneous multi-point ignition in the main chamber. We have examined the effects of the sub-chamber volume, the diameter and number of passage holes, and the equivalence $ratio({\Phi})$ on the combustion characteristics by means of burning pressure measurement and flame visualization. In a CVC, the overall burning time including the ignition delay became very short and the maximum burning pressure was slightly increased by the radical ignition(RI) method in comparison with those by the conventional spark ignition(SI) method. Combustible lean limit by RI method is extended by ${\Phi}=0.25$ compared with that by SI method. Also, In cases of charging the number and the diameter for the fixed total cross section of the passage holes, combustion period increased significantly at a sub-chamber with a single hole, but those of the other conditions had almost a similar tendency in the sub-chamber with 4 or more holes. regardless of equivalence ratio. Therefore, it was Proved that a critical cross section exists with the number of passage holes.

• Journal of Hydrogen and New Energy
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• v.28 no.2
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• pp.174-180
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• 2017

Recently, the world faces the environmental problem such as air pollution due to harmful gas discharged from car and abnormal climate due to the green-house gases increased by the discharge of $CO_2$. Compressed Natural Gas (CNG), one of alternative for this problem, is less harmful, compared to the existing fossil fuel, as gaseous fuel, and less carbon in fuel ingredients and carbon dioxide generation rate relatively favorable more than the existing fuel. However, CNG fuel has the weakness of slow flame propagation speed and difficult fast burn. On the other hand, hydrogen does not include carbon in fuel ingredients, and does not discharge harmful gas such as CO and HC. Moreover, it has strength of quick burning velocity and ignition is possible with small ignition energy source and it's has wide Lean Flammability Limit. If using this hydrogen with CNG fuel, the characteristics of output and discharge gas is improved by the mixer's burning velocity improved, and, at the same time, is possible to have stable lean combustion with the reduction of $CO_2$ expected. Therefore, this research tries to identify the characteristics of engine and emission gas when mixing CNG fuel and hydrogen in each portion and burning them in spark igniting engine, and grasp the lean combustion limit and emission gas characteristics according and use it as the basic data of hydrogen-CNG premixed engine.

• Journal of the Korean Institute of Gas
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• v.10 no.2 s.31
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• pp.33-39
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• 2006

For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, auto ignition temperature and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. For the safe handling of propane, explosion limit and autoignition temperature of combustion characteristics for propane were investigated. By using the literatures data, the lower and upper explosion limits of propane recommended 2.0 vol% and 10.0 vol%, respectively. Also autoignition temperatures of propane with ignition sources recommended $450^{\circ}C$ at the electrically heated cruicible fumace(the whole surface heating) and recommended about $960^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of propane are proposed. The values calculated by the proposed equations were a good agreement with the literature data.