scholarly journals Study on the Risk Assessment of Spontaneous Ignition and of Perilla Oil Cakes Associated Activation Energy

2021 ◽  
Vol 35 (2) ◽  
pp. 1-8
Author(s):  
Sung-Ho Byun ◽  
Yu-Jung Choi ◽  
Jae-Hoon Jeong ◽  
Jae-Wook Choi
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Ignition Temperature ◽  
Ignition Delay Time ◽  
Fire Risk ◽  
Spontaneous Ignition ◽  
Maximum Temperature ◽  
Perilla Oil ◽  
Oil Cakes ◽  
Critical Ignition

Perilla oil cakes are the residues of oil pressing processes, and used as fertilizers, feedstuff, food, etc. However, according to recent reports, perilla oil cakes often ignite spontaneously due to scorching heat, particularly in rice mills, general mills, and oil mills where large amounts of perilla oil cakes are stored. Thus, in this study, we attempted to elucidate the risk of spontaneous ignition of perilla oil cakes. For this purpose, thermogravimetry/differential thermal analysis (TG-DTA) was performed to identify thermal properties like weight reduction and heat generation, and spontaneous ignition was conducted for sample vessels of different thicknesses. The results showed that the ignition temperature of perilla oil cakes was 115 ℃ for the small (20 cm × 20 cm × 3 cm) vessel. The apparent activation energy associated with the critical ignition temperature was 60.74 kJ/mol. The ignition delay time and the time to reach maximum temperature were both found to increase with increasing vessel thickness. It was concluded that proper protection against heat must be in place because fire risk increases and spontaneous ignition can occur when large amounts of perilla oil cakes are accumulated.

scholarly journals Study on Sensitivity Differences of Critical Spontaneous Ignition Temperature between Alcohol and Hydrocarbon Fuels Based on Reaction Pathway

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 475
Author(s):  
Qiang Liu ◽  
Zhongchang Liu ◽  
Xiaoming Ren ◽  
Yongqiang Han ◽  
Jun Wang ◽  
...  
Keyword(s):  
Ignition Temperature ◽  
Reaction Pathway ◽  
Reaction Pathways ◽  
Spontaneous Ignition ◽  
Maximum Temperature ◽  
Elementary Reactions ◽  
Auto Ignition ◽  
Alcohol Fuel ◽  
High Efficient ◽  
Emission Regulations

In this article, the critical spontaneous ignition temperature of both hydrocarbon and alcohol fuel was acquired on a constant volume combustion bomb platform by slowly heating the inner charges, and then followed by using the CHEMKIN-PRO software to simulate the auto-ignition-dominated characteristic and parameter sensitivity of the two kinds of fuels. Results revealed that in different conditions, the critical spontaneous ignition temperature of methanol changed dramatically, with a maximum temperature of 50 K, while the counterpart temperature of n-heptane remained an invariable value of 553 K within a large changeable scope of temperature, and only a maximum temperature of 10 K was observed. The maximum difference of spontaneous ignition temperature between methanol and n-heptane reached 270 K. At the same time, a minimum difference of 170 K was obtained as well. The complete reaction of methanol requires 5 steps, involving 6 components and 11 elementary reactions. However, for the comparative part-n-heptane, more than 20 main self-ignition reactions were involved, which indicated that the whole reaction process of n-heptane has more reaction pathway branches and it was much more complicated compared to methanol. The differences of the reaction pathways triggered a considerable distinction of critical self-ignition temperature between the two charges, making a “step-by-step” spontaneous ignition combustion mode possible. In this way, a further high-efficient and clean combustion can be available to cater to much more stringent emission regulations in the future.

Activation Energy of Teak and Oak Wood Spontaneous Ignition

2014 ◽  
Vol 1001 ◽  
pp. 262-266 ◽  
Author(s):  
Jozef Martinka ◽  
Tomáš Chrebet
Keyword(s):  
Activation Energy ◽  
Ignition Temperature ◽  
Ignition Time ◽  
Test Procedure ◽  
Thermodynamic Temperature ◽  
Tectona Grandis ◽  
Spontaneous Ignition ◽  
Oak Wood ◽  
Teak Wood ◽  
The Difference

This article deals with evaluation of the spontaneous-ignition activation energy of the Teak wood (Tectona grandis L.f.) and the Oak wood (Quercus robur L.). Spontaneous-ignition activation energy was calculated from dependence of ignition time to inverse value of thermodynamic temperature. This dependence was measured in the hot-air (Setchkin) furnace according to ISO 871:2006 standard by modification of the test procedure. The modifications of test procedure lay in measurement of the time to ignition of sample loaded by various temperatures (at spontaneous ignition temperature and at temperatures above this value). The mass of investigated samples was (3 ± 0.05) g and its moisture contents was 0 wt %. The dimensions of sample was (20 x 20) mm, the third dimension was adjust to achieve required mass of sample. The activation energy of spontaneous-ignition for Teak wood was 78.23 kJ.mol-1 and for Oak wood was 59.24 kJ.mol-1. The spontaneous-ignition temperature for Teak wood was 460 °C and for Oak wood was 450 °C. Thus despite slight difference between spontaneous-ignition temperatures of investigated materials the difference between activation energy of spontaneous-ignition is significant.

scholarly journals Effect of Natural Aging on Oak Wood Fire Resistance

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2059
Author(s):  
Martin Zachar ◽  
Iveta Čabalová ◽  
Danica Kačíková ◽  
Tereza Jurczyková
Keyword(s):  
Activation Energy ◽  
Chemical Composition ◽  
Burning Rate ◽  
Fire Resistance ◽  
Ignition Temperature ◽  
Lignin Content ◽  
Spontaneous Ignition ◽  
Oak Wood ◽  
Elementary Analysis ◽  
Flame Ignition

The paper deals with the assessment of the age of oak wood (0, 10, 40, 80 and 120 years) on its fire resistance. Chemical composition of wood (extractives, cellulose, holocellulose, lignin) was determined by wet chemistry methods and elementary analysis was performed according to ISO standards. From the fire-technical properties, the flame ignition and the spontaneous ignition temperature (including calculated activation energy) and mass burning rate were evaluated. The lignin content does not change, the content of extractives and cellulose is higher and the content of holocellulose decreases with the higher age of wood. The elementary analysis shows the lowest proportion content of nitrogen, sulfur, phosphor and the highest content of carbon in the oldest wood. Values of flame ignition and spontaneous ignition temperature for individual samples were very similar. The activation energy ranged from 42.4 kJ·mol−1 (120-year-old) to 50.7 kJ·mol−1 (40-year-old), and the burning rate varied from 0.2992%·s−1 (80-year-old) to 0.4965%·s−1 (10-year-old). The difference among the values of spontaneous ignition activation energy is clear evidence of higher resistance to initiation of older wood (40- and 80-year-old) in comparison with the younger oak wood (0- and 10-year-old). The oldest sample is the least thermally resistant due to the different chemical composition compared to the younger wood.

Application of thermal ignition theory to determination of spontaneous ignition temperature limits of hydrocarbon-oxygen mixtures

1977 ◽  
Vol 355 (1681) ◽  
pp. 153-165 ◽  
Keyword(s):  
Heat Transfer ◽  
Activation Energy ◽  
Rayleigh Number ◽  
Ignition Temperature ◽  
Spontaneous Ignition ◽  
Thermal Ignition ◽  
Temperature Changes ◽  
Critical Boundary ◽  
Rate Of Heat Release

Measurements of temperature changes in decane-air mixtures near the critical boundary for spontaneous ignition indicate that, under conditions where heat transfer in the reacting gases takes place solely by conduction, temperature limits for ignition are in excellent agreement with predictions according to the conductive theory of thermal ignition. It is shown, however, that, by use of a derived relation between the dimensionless rate of heat release and the Rayleigh number, thermal ignition theory can be extended to the prediction of temperature limits under conditions where considerable convective heat transfer also takes place. Furthermore, the overall activation energy of the initial reactions involved in the oxidation of other alkanes has been shown to be a useful parameter for the prediction of the corresponding spontaneous ignition temperature limits.

Effect of different carbons on ignition temperature and activation energy of black powder

1977 ◽  
Vol 18 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Abraham D. Kirshenbaum
Keyword(s):  
Activation Energy ◽  
Ignition Temperature ◽  
Black Powder

scholarly journals Effect of boron on HEM radiant ignition characteristics

2021 ◽  
Vol 2057 (1) ◽  
pp. 012062
Author(s):  
A G Korotkikh ◽  
I V Sorokin
Keyword(s):  
Ignition Temperature ◽  
High Energy ◽  
Butadiene Rubber ◽  
Radiant Heating ◽  
Energy Materials ◽  
High Energy Materials ◽  
Bimetallic Systems ◽  
Critical Ignition ◽  
Boron Particles ◽  
Ignition Characteristics

Abstract The paper presents the ignition characteristics of high-energy materials (HEMs) containing ammonium perchlorate, butadiene rubber, and a mixture of Al/B nanopowders with different component ratios. Bimetallic systems based on aluminum with boron increase the reactivity and intensify the ignition of boron particles, which helps to decrease the critical ignition conditions of HEMs during heating. It is shown that the use of systems based on aluminum-boron reduces the delay time (by 17–52 %) and the ignition temperature of propellants in comparison with a HEM containing aluminum powder, and increases the activation energy of HEM during radiant heating.

EXPERIMENTAL AND NUMERICAL STUDY OF THERMAL ANALYSIS OF HIGH-SPEED FRICTION BRAKING SYSTEM

2011 ◽  
Vol 10 (01) ◽  
pp. 135-142
Author(s):  
CHUNMEI ZHANG ◽  
YONGFENG LI
Keyword(s):  
Thermal Analysis ◽  
Friction Surface ◽  
High Speed ◽  
Material Selection ◽  
Numerical Study ◽  
Friction Pair ◽  
Maximum Temperature ◽  
Dimensionless Time ◽  
Braking System ◽  
Friction Braking System

Thermal analysis can be used as one of the basis for the friction pair material selection in high-speed friction braking system. In this study, the experimental results showed that surface temperature could be reduced by increasing the radius of the friction disk or thermal conductivity coefficient of disk material with stable braking; In the early stage of long braking, the temperature on the friction surface rises rapidly, but further braking does not lead to a significant rise in temperature; In the case of short braking, there is not enough time for the friction surface to reach the critical temperature, and the disk surface reaches the maximum temperature at the end of braking. During long braking, the dimensionless time capacity of the friction surface reaching the highest temperature is F0 ≈ 0.1F0s.

Phase Formation Kinetics in Sol-Gel Derived Strontium Bismith Tantalate

2001 ◽  
Vol 666 ◽  
Author(s):  
Yun-Mo Sung ◽  
Woo-Chul Kwack
Keyword(s):  
Activation Energy ◽  
Thermal Analysis ◽  
Phase Formation ◽  
Sol Gel ◽  
Avrami Exponent ◽  
Fluorite Phase ◽  
X Ray Diffraction ◽  
Aurivillius Phases ◽  
Formation Kinetics ◽  
Isothermal Kinetic

ABSTRACTPhase formation characteristics of Sr0.7Bi2.4Ta2O9 (SBT) powder, synthesized via sol-gel and pyrolysis process, was investigated by using thermal analysis. Each of the two exotherms, appearing in differential thermal analysis (DTA) scan curves, was identified as crystallization of fluorite phase and transformation of fluorite to aurivillius phase, respectively by using x-ray diffraction (XRD). By applying non-isothermal kinetic analyses to the DTA results, activation energy values for the formation of fluorite and aurivillius phases were determined as 192 and 375 kJ/mol, respectively and Avrami exponent values for each reaction were determined as 0.91 and 0.96, respectively. These activation energy and Avrami exponent values were discussed in detail to understand phase formation mechanism in SBT system.

Materials for Safety and Security

2020 ◽  
pp. 288-320
Author(s):  
Jozef Martinka ◽  
Janka Dibdiakova
Keyword(s):  
Hydrogen Cyanide ◽  
Ignition Temperature ◽  
Fire Risk ◽  
Combustion Products ◽  
Security Engineering ◽  
Insulating Materials ◽  
Properties Of Materials ◽  
Materials Used ◽  
Carbon Monoxide Yield ◽  
The Impact

This chapter deals with materials used in safety and security engineering. The most commonly used materials in this field include shielding materials, materials for protective suits, electrically insulating materials and materials for fire protection. The first part of the chapter describes the properties of materials used in the above applications. The second part of the chapter focuses on characteristics of materials that accurately describe their fire risk. The fire risk of a material is quantified by its resistance to ignition (determined generally by critical heat flux and ignition temperature) and by the impact of the fire on the environment. The impact of fire is usually determined by the heat release rate, toxicity of combustion products (primarily determined by carbon monoxide yield and for materials that contain nitrogen, also through the hydrogen cyanide yield) and the decrease of visibility in the area (depending on the geometry of the area and the smoke production rate).

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