• Title/Summary/Keyword: Autoignition temperature

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Measurement and Investigation of Combustible Characteristics for Risk Assessment of Toluene (톨루엔의 위험성 평가를 위한 연소특성치 측정 및 고찰)

  • Ha, Dong-Myeong;Jeong, Kee-Sin
    • Fire Science and Engineering
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    • v.24 no.2
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    • pp.76-81
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    • 2010
  • For the safe handling of toluene, explosion limit at $25^{\circ}C$ and the temperature dependence of the explosion limits were investigated. And flash point and AIT (Autoignition Temperature) for toluene were experimented. By using the literature data, the lower and upper explosion limits of toluene recommended 1.13 vol% and 7.9 vol%, respectively. In this study, measured the lower and upper flash points of toluene by air-blowing tester were $5^{\circ}C$ and $40^{\circ}C$, respectively. And measured the upper flash points of toluene by Setaflash tester was $41.5^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for toluene, and the experimental AIT of toluene was $547^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of toluene is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

Investigation of Combustion Properties for Using Safe Hydrogen (안전한 수소 이용을 위한 연소특성치 고찰)

  • Ha, Dong-Myeong
    • Journal of the Korean Institute of Gas
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    • v.12 no.2
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    • pp.1-6
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    • 2008
  • For the safety design and operation of many gas process, it is necessary to know certain explosion limit, flash point, autoignition temperature (AIT) and minimum oxygen concentration of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. In this study for the safe handling of hydrogen, explosion limit and AIT of combustion properties for hydrogen were investigated. By using the literatures data, the lower and upper explosion limits of hydrogen recommended 4.0 vol% and 77.0 vol%. Also the AIT of hydrogen with ignition sources recommended $400^{\circ}C$ at the electrically heated crucible furnace (the whole surface heating) and recommended $640^{\circ}C$ at the local hot surface. The new equations for predicting the temperature and the pressure dependence of the explosion limits of hydrogen are proposed. The values calculated by the proposed equations were a good agreement with the literature data.

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Measurement and Prediction of Autoignition Temperature (AIT) and Ignition Delay Time of n-Pentanol and p-Xylene Mixture (n-Pentanol p-Xylene 과 혼합물의 최소자연발화온도와 발화지연시간의 측정 및 예측)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.31 no.5
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    • pp.1-6
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    • 2017
  • The fire and explosion properties of combustible materials are necessary for the safe handling, storage, transportation and disposal. Typical combustion characteristics for process safety include auto ignition temperature(AIT). The AIT is an important index for the safe handling of combustible liquids. The AIT is the lowest temperature at which the material will spontaneously ignite. In this study, the AITs and ignition delay times of n-pentanol and p-xylene mixture were measured by using ASTM E659 apparatus. The AITs of n-pentanol and p-xylene which constituted binary system were $285^{\circ}C$ and $557^{\circ}C$, respectively. The experimental AITs and ignition delay times of n-pentanol and p-xylene mixture were a good agreement with the calculated AITs and ignition delay times by the proposed equations with a few A.A.D. (average absolute deviation). Therefore, it is possible to estimate the AITs and ignition delay times in other compositions of n-pentanol and p-xylene mixture by using the predictive equations which presented in this study.

Effect of Ignition Delay Time on Autoignited Laminar Lifted Flames (자발화된 층류 부상화염에 대한 점화지연시간의 영향)

  • Choi, Byung-Chul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.10
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    • pp.1025-1031
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    • 2011
  • Autoignition characteristic is an important parameter for designing diesel or PCCI engines. In particular, diesel spray flames are lifted from the nozzle and the initial flame is formed by an autoignition phenomenon. The lifted nature of diesel spray flames influences soot formation, since air will be entrained into the spray core by the entrainment of air between the nozzle region and the lifted flame base. The objective of the present study was to identify the effect of heat loss on the ignition delay time by adopting a coflow jet as a model problem. Methane ($CH_4$), ethylene ($C_2H_4$), ethane ($C_2H_6$), propene ($C_3H_6$), propane ($C_3H_8$), and normal butane (n-$C_4H_{10}$) fuels were injected into high temperature air, and the liftoff height was measured experimentally. As the result, a correlation was determined between the liftoff height of the autoignited lifted flame and the ignition delay time considering the heat loss to the atmosphere.

A Study of the Temperature Elevation Due to the Pre-flame Reaction in a Spark-Ignition Engine Using CARS Technique (CARS 측정 기술을 이용한 스파크 점화 기관에서의 화염 전 화학 반응에 의한 온도 변화에 관한 연구)

  • 최인용;전광민;박철웅;한재원
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.5
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    • pp.9-16
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    • 2001
  • End-gas temperatures were measured using CARS technique in a conventional DOHC spark- ignition engine fueled with PRF80. The measured pressure data were analyzed using band pass filter method. The measured CARS temperatures were compared with adiabatic core temperatures calculated from measured pressures. Significant heating by pre-flame reaction in the end gas zone was observed in the late part of compression stroke under both knocking and non-knocking conditions. CARS temperatures measured at 10 crank angle degree before knock occurrence was higher than adiabatic core temperatures. These results indicate that there exist some exothermic reactions in low pressure and temperature region. CARS temperatures began to be higher than the adiabatic core temperature when the end-gas temperatures reached look. The temperature elevation due to the pre-flame reaction correlated better with CARS temperature than with cylinder pressure.

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A Study of the Temperature Elevation Due to the Pre-flame Reaction Using CARS (CARS 를 이용한 스파크 점화 기관에서의 화염 전화학 반응에 의한 온도 변화에 관한 연구)

  • Choi, In-Yong;Chun, Kwang-Min;Park, Chul-Woung;Hahn, Jae-Won
    • 한국연소학회:학술대회논문집
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    • 2000.05a
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    • pp.85-92
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    • 2000
  • End-gas temperatures were measured using CARS technique in a conventional DOHC spark-ignition engine fueled with PRF80. The measured pressure data were analyzed using band pass filter method. The measured CARS temperatures were compared with adiabatic core temperatures calculated from measured pressure. Significant heating by pre-flame reaction in the end gas was observed in the late part of compression stroke under both knocking and non-knocking condition. CARS temperatures measured at 10 crank angle degree before knock occurrence was higher than adiabatic core temperatures. These results indicate that there exist some exothermic reactions in low pressure and temperature region. CARS temperatures began to be higher than the adiabatic core temperature when the end-gas temperatures reached 700 K. The temperature elevation due to the pre-flame reaction correlated better with CARS temperature than with cylinder pressure.

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Numerical Investigation of Exhaust Gas Recirculation Effect under Boost Pressure Condition on Homogeneous Charge Compression Autoignition (HCCI엔진의 과급조건에서 EGR영향에 대한 수치해석적 연구)

  • Oh, Chung Hwan;Jamsran, Narankhuu;Lim, Ock Tack
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.6
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    • pp.451-464
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    • 2014
  • This study used numerical methods to investigates investigate the exhaust gas recirculation (EGR) effect under the condition of boost pressure condition on a homogeneous charge compression ignition (HCCI) combustion engine using numerical methods. The detailed chemical-kinetic mechanisms and thermodynamic parameters for n-heptane, iso-octane, and PRF50 from the Lawrence Livermore National Laboratory (LLNL) are were used for this study. The combustion phase affects the efficiency and power. To exclude these effects, this study decided to maintain a 50 burn point (CA50) at 5 CA after top dead center aTDC. The results showed that the EGR increased, but the low temperature heat release (LTHR), negative temperature coefficient (NTC), and high temperature heat release (HTHR) were weakened due by theto effect of the O2 reduction. The combined EGR and boost pressure enhanced the autoignition reactivity, Hhence, the LTHR, NTC, and HTHR were enhanced, and the heat-release rate was increased. also In addition, EGR decraeased the indicated mean effective pressure (IMEP), but the combined EGR and boost pressure increased the IMEP. As a results, combining the ed EGR and boost pressure was effective to at increase increasing the IMEP and maintaining the a low PRR.

A Study on Autoignition Characteristics of Methylmethacrylate-butadiene-styrene Copolymer (MBS 공중합물의 자연발화 특성에 관한 연구)

  • 목연수;최재욱
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.83-88
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    • 2001
  • This study was preformed by measuring the minimum ignition temperature of MBS according to the change of sample vessel size and the minimum ignition temperature of MBS dust cloud The minimum ignition temperature of MBS product decreased as the vessel size was large, and it was obtained in the range from $120.5^{\circ}C$ to $94.5^{\circ}C$ and the apparent activation energy was obtained with 32.94Kcal/mol. The minimum ignition temperature of MBS dust cloud was measured by using Godbert-Greenwald furnace and it was obtained at $407^{\circ}C$ with the sample of 0.4g in the air and the ignition of dust cloud was not occurred below 13% oxygen concentration.

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Risk Assessment by Means of Measurement of Combustible Characteristics for n-Nonanol (노말노난올의 연소특성치 측정에 의한 위험성 평가)

  • Ha, Dong-Myeong
    • Fire Science and Engineering
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    • v.26 no.2
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    • pp.84-89
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    • 2012
  • For the safe handling of n-nonanol, this study was investigated the explosion limits of n-nonanol in the reference data. The flash points and AITs (autoignition temperatures) by ignition delay time were experimented. As a results, the lower and upper explosion limits of n-nonanol recommended 0.8 Vol.% and 6.1 Vol.%, respectively. The lower flash points of n-nonanol by using closed-cup tester were experimented $94{\sim}97^{\circ}C$. The lower flash points of n-nonanol by using open cup tester were experimented $103{\sim}104^{\circ}C$. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for n-nonanol. The experimental AIT of n-nonanol was $270^{\circ}C$.