• Korean Chemical Engineering Research
• /
• v.55 no.5
• /
• pp.623-628
• /
• 2017

Using wood pellets, which are used as fuel for thermal power generation plants, as test specimens, the minimum spontaneous ignition temperatures according to the size of the container for the test specimens were measured, and by applying the Frank-Kamenetskii theories on thermal energy to these temperatures, the danger factor of the materials were calculated by deriving the apparent activation energies. The results confirmed that the ignition threshold temperature decreased as the size of the container increased and that the spontaneous ignition energy was 37.83 kcal/mol. The results also confirmed that the larger the container for the test specimens was the time to arrive at the spontaneous ignition time and maximum temperature also increased.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.7
• /
• pp.721-727
• /
• 2010

The spontaneous ignition of coal stockpile causes serious safety and economic problems. Such spontaneous ignition occurs in coal stockpile when the rate of heat released by the oxidation of coal is greater than the rate of heat lost to the surroundings. In this study, a two-dimensional unsteady model is adopted for studying spontaneous ignition and the numerical results are compared with experimental results. The numerical results are in a good agreement with the experimental ones. Depending on the porosity, the internal maximum temperature, pressure, and oxygen mass fraction during spontaneous ignition are investigated. On the basis of the numerical results, the transient temperature variations for several shapes of coal stockpiles are analyzed. Further, the physical mechanisms of hot-spot formation and spontaneous ignition are analyzed.

• Journal of the Korean Society of Safety
• /
• v.9 no.3
• /
• pp.74-81
• /
• 1994

The critical spontaneous ignition temperature for activated carbon were observed by performing experiments for granulated activated carbon with varying the period. As the results of the experiments, the critical spontaneous ignition temperature according to period of 0.5hr, 1.5hr and 2.5hr was 177.5$^{\circ}C$, 176.5$^{\circ}C$ and 172.5$^{\circ}C$ respectively, and the approximate expression of the critical spontaneous ignition temperature obtained for ambient temperature amplitudes was as follow ; $\delta$$_{c}$ (X, $\omega$)=$\delta$$_{c}${1-0.381 exp(-0.930.$\omega$$^{0.811}$)}.

• Journal of the Korean Solar Energy Society
• /
• v.36 no.2
• /
• pp.73-78
• /
• 2016

This study investigates the main factors of fire prevention, such as spontaneous ignition and flash point, while using Diehylene Glycol (DEG) as the antifreeze for automobile and industrial machines. Our results show the flash point of $142^{\circ}C$ and the minimum ignition temperature of $388^{\circ}C$ in the range of $130{\mu}{\ell}{\sim}150{\mu}{\ell}$. By increasing temperature to ignite in 1 second, an instantaneous ignition temperature of the sample is $569^{\circ}C$ in the sample amount of $140{\mu}{\ell}$.

• Journal of the Korean Society of Combustion
• /
• v.18 no.3
• /
• pp.31-37
• /
• 2013

Numerical simulations are conducted to investigate the feature of spontaneous ignition of hydrogen within a certain length of downstream tube released by the failure of pressure boundaries of various geometric assumption. The results show that the ignition feature can be varied with the shape of pressure boundary. The ignition at the contact region are developed at the spherical pressure boundaries due to multi-dimensional shock interactions, whereas the local ignition is developed in limited area such as boundary layer at the planar pressure boundary conditions. The spontaneous ignition inside the tube can be generated from the reaction region of only boundary layer regardless of existence of the reaction of core region.

• Korean Chemical Engineering Research
• /
• v.59 no.2
• /
• pp.225-231
• /
• 2021

Sesame seed oil cakes are classified as the animal or plant origin among the flammable liquids, and the fire occurs due to the spontaneous ignition through the accumulation of heat during the storage of residues after the extraction of sesame oil. In order to elucidate the cause of the spontaneous ignition of sesame seed oil cakes, the thickness (3 cm, 5 cm, 7 cm and 14 cm) of the sample container was varied, and the spontaneous ignition temperature was measured depending on the storage volume. Thus, the spontaneous ignition temperature was measured to be 180 ℃ at the thickness of 3 cm, 160 ℃ at 5 cm, 145 ℃ at 7 cm and 130 ℃ at 14 cm. As the thickness of the sample container increased, the critical ignition temperature decreased, and the induction time to spontaneous ignition and the time to reach the maximum temperature became longer. Furthermore, the apparent activation energy by the critical ignition temperature, which is the average temperature of ignition and non-ignition, was 97.10 [kJ/mol]. With these data, ignition characteristics of sesame seed oil cakes were determined.

• Journal of the Korean Applied Science and Technology
• /
• v.39 no.2
• /
• pp.368-376
• /
• 2022

Spontaneous ignition occurs in industrial sites or anywhere in our lives, and is a phenomenon in which a substance ignites itself without an ignition source in the atmosphere. As the rate of chemical reaction increases, the heat generated increases, and the risk of spontaneous ignition increases. In this study, safe raw materials used for food and cosmetics were mixed to prepare coal spontaneous ignition prevention agents specifically among various spontaneous ignition phenomena. The effect of suppressing spontaneous combustion of coal was confirmed through lab and field tests with low-calorie, low-grade coal from Indonesia. As a result of the outdoor field test, the ignition prevention agent manufactured in this study compared with the control group(Fire after 90 days) showed excellent ignition inhibitors for more than 120 days. In addition, CO concentration control was confirmed by comparing the concentration of carbon monoxide for 50 days at the indoor coal yard. It was confirmed that the results were better than the comparative group coal and the existing anti-firing method. In addition, the possibility of coal fire prevention agents for indoor coal farms will be applied from 2024 was confirmed by studying the environment and safety of workers' working environments through official test such as soil and water quality test, MSDS of coal fire prevention agents in consideration of working workers, water quality, and eye irritation tests.

• Journal of the Korean Institute of Gas
• /
• v.16 no.2
• /
• pp.45-51
• /
• 2012

The MSITs(Minimum Spontaneous Ignition Temperatures) or AITs(Autoignition Temperatures) describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. This study measured the MSITs(Minimum Spontaneous Ignition Temperatures) of n-pentanol+ethylbenzene system by using ASTM E659 apparatus. The MSITs of pure n-pentanol and ethylbenzene were $285^{\circ}C$ and $475^{\circ}C$, respectively. The experimental MSITs of n-pentanol+ethylbenzene system were a in good agreement with the MSIT calculated by the proposed equations with a few A.A.D.(average absolute deviation).

• 한국연소학회:학술대회논문집
• /
• 2012.11a
• /
• pp.93-96
• /
• 2012

The spontaneous ignition mechanism of high pressure hydrogen gas released into tube is well-deduced from previous studies. However, those results have a limit because the studies have been conducted at low burst pressure of about 10 MPa. In this study, the process or ignition feature are investigated with higher burst pressure of up to 30 MPa through numerical analysis. The results show that the trend of ignition became to be different with a burst pressure. While two reaction regions is important to initiate the ignition when burst pressure is about 10 MPa, the reaction of the core region does not play a role in ignition inside the tube when a burst pressure is above 20 MPa.

• Journal of the Korean Society of Safety
• /
• v.22 no.5
• /
• pp.77-83
• /
• 2007

This study is conducted on spontaneous ignition temperature and activation energy of Hydroxypropyl Methyl Cellulose(HMC) powder. HMC is a kind of cellulose derivative and used as additives for building material, surface coating, printing ink, adhesives, cosmetics and medical supplies. So this material has been widely used as important additive in the chemical industry fields and a mount of production has increased year by year. Therefore, it is very important to find out the thermal ignition characteristics of its danger and the critical ignition temperature. This study was performed by the Spontaneous Ignition Tester(SIT) and so on. Based on the data of the SIT-II, the critical ignition point of HMC is about $186^{\circ}C$ which is slightly lower than normal cellulose.