• Title/Summary/Keyword: auto ignition temperatures

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A Study on Characteristics of Auto Ignition and Activation Energy of Ethylene Glycol and Diethylene Glycol (Ethylene Glycol과 Diethylene Glycol의 자연발화 특성과 활성화에너지에 관한 연구)

  • Kim, Jung-Hun;Choi, Jae-Wook
    • Journal of the Korean Institute of Gas
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    • v.20 no.2
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    • pp.16-22
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    • 2016
  • Auto ignition characteristic is an important factor for handling combustible substance and fire prevention. This research studied about auto ignition characteristic and activation energy of Ethylene Glycol (EG) and Diethylene Glycol (DEG) by using ASTM D2155 type ignition temperature measuring apparatus. As the auto ignition temperatures, it was possible to get $434^{\circ}C$ for EG within sample amount range of $75{\sim}160{\mu}l$ and $387^{\circ}C$ for DEG within sample amount range of $130{\sim}150{\mu}l$. Also, it was possible to get $579^{\circ}C$ and $569^{\circ}C$ as instantaneous ignition temperatures with sample amount of $140{\mu}l$ for EG and DEG respectively. By using least square method from Semenov equation on measured ignition temperature and ignition delay time from this study, it was possible to calculate activation energy of EG as 25.41 Kcal/mol and DEG as 14.07 Kcal/mol. Therefore, it was possible to claim that DEG has more risk of auto ignition since the auto ignition temperature, instantaneous ignition temperature and activation energy of DEG is lower than EG.

Characteristic of Auto Ignition Temperature due to the Mixture Ratio of Ethylene Glycol and Water (Ethylene Glycol과 물의 혼합비에 따른 자연발화온도 특성)

  • Kim, Jung-Hun;Choi, Jae-Wook
    • Fire Science and Engineering
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    • v.30 no.1
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    • pp.24-30
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    • 2016
  • Autoignition characteristic is an important factor of all combustible substances, and a critical determinant in assessing the effectiveness of fire hazard prevention. This study investigated the autoignition characteristic of mixtures of Ethylene Glycol and water using an ASTM D2155 type ignition temperature measuring apparatus. It was possible to get the minimum temperature as $434^{\circ}C$ from 100% Ethylene Glycol within range of $75{\sim}160{\mu}l$. A volume of $100{\sim}125{\mu}l$ of a mixed sample of Ethylene Glycol and water (80 : 20) was ignited at the same temperature ($434^{\circ}C$). Also it was possible to get the auto ignition temperature as $437^{\circ}C$ from a mixed sample of Ethylene Glycol and water (60 : 40) within range of $120{\sim}160{\mu}l$. The instantaneous ignition temperatures determined for $125{\mu}l$ of each of the three samples were $579^{\circ}C$, $595^{\circ}C$ and $611^{\circ}C$, respectively. Both auto ignition temperatures and instantaneous ignition temperatures were increased through the addition of water to the samples.

Effect of Ambient Temperature and Droplet Size of a Single Emulsion Droplet on Auto-ignition and Micro-explosion (단일 유화액적에서의 분위기 온도와 액적크기에 따른 자발화와 미소폭발의 영향)

  • Jeong, In-Cheol;Lee, Kyung-Hwan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.15 no.1
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    • pp.49-55
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    • 2007
  • The characteristics of auto-ignition and combustion process of a single droplet of emulsified fuel suspended in a high-temperature air chamber have been investigated experimentally with various droplet sizes, surrounding temperatures, and water contents. The used fuels was n-Decane and it was emulsified with varied water contents whose maximum is 30%. The high-speed camera has been adopted to measure the ignition delay and flame life time. It was also applied to observe micro-explosion behaviors. The increase of droplet size and chamber temperature cause the decrease of the ignition delay time and flame life-time. As the water contents increases, the ignition delay time increases and the micro-explosion behaviors are strengthened. The starting timings of micro-explosion and fuel puffing are compared for different droplet sizes and the amount of water contents.

Characteristics of Chemical Reaction and Ignition Delay in Hydrogen/Air/Diluent Mixtures (수소/공기/희석제 혼합기의 점화지연과 화학반응 특성연구)

  • Lee, Dong Youl;Lee, Eui Ju
    • Journal of the Korean Society of Safety
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    • v.36 no.3
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    • pp.1-6
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    • 2021
  • Hydrogen is considered a cleaner energy source than fossil fuels. As a result, the use of hydrogen in daily life and economic industries is expected to increase. However, the use of hydrogen energy is currently limited because of safety issues. The rate of combustion of the hydrogen mixture is about seven times higher than that of hydrocarbon fuels. The hydrogen mixture is highly flammable and has a low minimum ignition energy. Therefore, it presents considerable risks for fire and explosions in all areas of hydrogen manufacturing, transportation, storage, and use. In this study, the auto-ignition characteristics of hydrogen were investigated numerically for diluted hydrogen mixtures. Auto-ignition temperature, a critical property predicting the fire and explosion risk in hydrogen combustion, was determined in well-stirred reactors. When N2 and CO2 were used to dilute the hydrogen/air mixture, the ignition delay time increased with increasing dilution ratios in both cases. The CO2-diluted mixtures exhibited a longer ignition delay than the N2-diluted mixtures. We also confirmed that lower initial ignition temperatures increased the ignition delay times at 950 K and above. Overall, the auto-ignition characteristics, such as the concentrations of participating species and ignition delay times, were primarily affected by the initial temperature of the mixture.

Study on Auto Ignition of Hybrid Rocket Using $N_2O$ Catalytic Decomposition ($N_2O$ 촉매 분해를 이용한 하이브리드 로켓 자연 점화 연구)

  • Yong, Sung-Ju;Kim, Tae-Gyu
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.202-205
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    • 2010
  • Auto ignition of hybrid rocket using $N_2O$ catalytic decomposition was studied in the present study. The hybrid rocket consists of catalytic igniter, solid fuel, combustor, and nozzle. The Ru/$Al_2O_3$ catalyst for $N_2O$ decomposition was synthesized by an impregnation method, and $N_2O$ conversion as reaction temperatures was measured. The temperature change of the catalytic ignitor was measured at the operating condition, and the possibility for the auto ignition of hybrid rocket was validated.

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A Study on the Ignition Temperature and Ignition Induction Time According to Storage Amount of Wood Pellets (우드펠릿의 저장량에 따른 발화온도 및 발화유도시간에 관한 연구)

  • Kim, Hyeong-Seok;Choi, Yu-Jung;Kim, Jung-Hun;Jeong, Phil-Hoon;Choi, Jae-Woo
    • Fire Science and Engineering
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    • v.33 no.1
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    • pp.7-14
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    • 2019
  • While wood pellets are often used as a fuel in thermoelectric power plants and firewood boilers, there is a risk of ignition temperature when strong wood pellets, which have a high calorific value, for prolonged periods of time. In this research study, the minimum auto ignition temperature and the ignition limitation temperature according to the change in flow rate depending on the size of the test vessel were calculated, and based on these temperatures, the apparent activation energy was calculated to predict the combustive properties of the material. The apparent activation energy was calculated to be 190.224 kJ/mol. The thicker the sample is storage in the vessel, the longer the ignition induction time was due to the increased difficulty in heat being transferred from the surface of the vessel to the middle section area of the vessel. For vessel of the same size, the higher the flow rate, the lower the auto ignition temperature was. It was also confirmed that increases in the size of the test vessel lowered the auto ignition temperature and increased the ignition induction time.

Effects of Fuel Blending Ratio and Oxygen Concentration on Auto-ignition Characteristics of n-Decane/Ethanol Blended Fuels (연료 혼합비율 및 산소농도가 노말데케인/에탄올 혼합연료의 점화특성에 미치는 영향)

  • Oh, Chae Ho;Kang, Ki Joong;Choi, Gyung Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.11
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    • pp.749-757
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    • 2017
  • To cope with the development of alternative fuels and international environmental regulations, this study provides a numerical analysis of the effects of composition and temperature changes of n-decane and ethanol on auto-ignition characteristics. CHEMKIN-PRO is used as the analysis program and the LLNL model is used as the reaction model. The numerical results show that the ignition delay time increases as the mole fraction of ethanol increases for temperatures below 1000 K, where low temperature reactions occur. Because of the high octane number of ethanol, the high percentage of ethanol delays the increase in the concentration of OH radicals that cause ignition. The oxygen concentration in the mixture is changed to apply the exhaust gas recirculation and a numerical analysis is then performed. As the oxygen concentration decreases, the total ignition delay time increases because the nitrogen gas acts as a thermal load in the combustion chamber.

Investigation of Reliability of Flash Points and Autoignition Temperatures of Acids (산류(Acids)의 인화점과 최소자연발화온도의 신뢰성 고찰)

  • Ha, Dong-Myeong
    • Journal of the Korean Society of Safety
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    • v.24 no.2
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    • pp.42-47
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    • 2009
  • The flash point and the AIT(auto-ignition temperature) are the most important combustible properties used to determine the potential for the fire and explosion hazards of flammable material. In order to know the accuracy of data in MSDS(Material Safety Data Sheet), the flash point of n-acids were measured by using Pensky-Martens closed cup tester(ASTM D93), Setaflash closed cup tester(ASTM D3278), Tag open cup tester(ASTM D1310) and Cleveland open cup tester(ASTM D92). Also, the AIT of n-acids were measured by using ASTM E659-78 tester. The measured the flash points and the AIT were compared with literatures and MSDS in KOSHA. The measured the flash points and the AIT were different from those in literatures and MSDS. Therefore, This paper shows that it is needed to investigate the MSDS compatibility of n-acids for the fire safety objectives.

Effects of Pilot Injection Method Following the Main Injection on Ignition Promotion and Exhaust Gas Reduction in a Diesel-Fueled HCCI Engine (디젤 예혼합압축착화엔진에서 주연료 분사 후 점화 연료 분사 방법을 통한 점화 촉진과 배기가스 개선 효과)

  • Kook, Sang-Hoon;Bae, Choong-Sik
    • 한국연소학회:학술대회논문집
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    • 2003.05a
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    • pp.27-32
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    • 2003
  • Diesel-Fueled HCCI(Homogeneous Charge Compression Ignition) Engine is an advanced combustion process explained as a premixed charge of diesel fuel and air is admitted into the cylinder and compression ignited. It has possibility to reduce NOx by spontaneous auto-ignition at multiple points that allows very lean combustion resulting in low combustion temperatures. Also PM could be reduced by the premixed combustion and no fuel-rich zones. But HCCI couldn't be realized because of the difficulties in vaporizing the diesel, control of combustion phase directly. To solve these problems, new fuel injection strategy, explained as the pilot fuel injection to promote ignition near TDC following the main fuel injection at the extremely advanced timing, is applied during the compression ratio is varied from 18.9:1 to 27.7:1 This is not a pilot fuel to promote the ignition but also the direct control method of the combustion phase. Experimental result shows the pilot fuel injection promote the ignition and the compression ignition of the HCCI engine is achieved as compression ratio becomes higher. Also there is an optimal pilot fuel injection timing for the HCCI combustion. NOx is reduced more than 90% compared to DI-Diesel case but PM and THC emission needs more investigation.

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A Study on the Appropriateness of the Combustible Properties of MSDS for o-Cresol (오토크레졸의 MSDS 연소특성치의 적정성 연구)

  • Ha, Dong-Myeong
    • Journal of the Korean Society of Safety
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    • v.30 no.2
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    • pp.21-26
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    • 2015
  • For the safe handling of o-cresol, this study was investigated the explosion limits of o-cresol in the reference data. The flash points and AITs(auto-ignition temperatures) by ignition delay time were experimented. The lower flash points of o-cresol by using closed-cup tester were experimented in $77^{\circ}C$ and $80^{\circ}C$. The lower flash points of o-cresol by using open cup tester were experimented in $86^{\circ}C$ and $87^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659 tester for o-cresol. The AIT of o-cresol was experimented as $495^{\circ}C$. The lower explosion limit(LEL) by the measured the lower flash point for o-cresol was calculated as 1.27 Vol%.