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 Effects of temperature gradient and particle size on self-ignition temperature of low-rank coal excavated from inner Mongolia, China

2019 ◽  
Vol 6 (9) ◽  
pp. 190374 ◽  
Author(s):  
Yongjun Wang ◽  
Xiaoming Zhang ◽  
Hemeng Zhang ◽  
Kyuro Sasaki
Keyword(s):  
Activation Energy ◽  
Particle Size ◽  
Temperature Gradient ◽  
Ignition Temperature ◽  
Coal Particle ◽  
Critical Value ◽  
Low Rank ◽  
Low Rank Coal ◽  
Coal Particles ◽  
Effects Of Temperature

This study investigates the effects of temperature gradient and coal particle size on the critical self-ignition temperature T CSIT of a coal pile packed with low-rank coal using the wire-mesh basket test to estimate T CSIT based on the Frank–Kamenetskii equation. The values of T CSIT , the temperature gradient and the apparent activation energy of different coal pile volumes packed with coal particles of different sizes are measured. The supercriticality or subcriticality of the coal is assessed using a non-dimensional index I HR based on the temperature gradient at the temperature cross-point between coal and ambient temperatures for coal piles with various volumes and particle sizes. The critical value I HRC at the boundary between supercriticality and subcriticality is determined as a function of pile volume. The coal status of supercritical or subcritical can be separated by critical value of I HR as a function of pile volume. Quantitative effects of coal particle size on T CSIT of coal piles are measured for constant pile volume. It can be concluded that a pile packed with smaller coal particles is more likely to undergo spontaneous combustion, while the chemical activation energy is not sensitive to coal particle size. Finally, the effect of coal particle size on T CSIT is represented by the inclusion of an extra term in the equation giving T CSIT for a coal pile.

Analyses of Coal and Sewage Sludge Co-Combustion Using Coats-Redfern Model

2012 ◽  
Vol 518-523 ◽  
pp. 3271-3274
Author(s):  
Huan Li ◽  
Yang Yang Li ◽  
Yi Ying Jin
Keyword(s):  
Activation Energy ◽  
Ignition Temperature ◽  
Burning Velocity ◽  
Fire Behavior ◽  
Volatile Matter ◽  
Water Evaporation ◽  
Fixed Carbon ◽  
Carbon Combustion ◽  
Blend Fuel ◽  
Dried Sludge

The co-combustibility of coal and sludge was investigated with thermogravimetric analysis. The results show that the burning process of sludge can be divided into three phases: water evaporation, volatile matter volatilization and combustion, fixed carbon combustion and burning out. The ignition temperature of sludge is only 260 degree centigrade at the beginning of volatile matter combustion. The addition of wet sludge or dried sludge will reduce the burning velocity of coal, and also decrease the ignition temperature. However the blend of coal and sludge has not an obvious stage of the volatile matter volatilization and combustion. The activation energy of the sludge is lower than that of the coal. The addition of wet sludge or dried sludge will decrease the activation energy of the blend fuel, and improve the fire behavior. On the whole, the sludge addition has little influence on the combustion of the coal when the addition ratio is lower than 10%.

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 Effect of Lubricant Additives on the Oxidation Characteristics of Diesel Engine Particulate Matter

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Guangju Xu ◽  
Yang Zhao ◽  
Mingdi Li ◽  
Yanbin Hu ◽  
Ling Lin
Keyword(s):  
Activation Energy ◽  
Particulate Matter ◽  
Diesel Engine ◽  
Ignition Temperature ◽  
Characteristic Temperature ◽  
Cetane Number ◽  
Lubricant Additives ◽  
Bench Test ◽  
Rotating Speed ◽  
Particulate Matter Oxidation

Three common lubricant additives, including an antioxidant, detergent, and an antifoamer, were added to diesel fuel to perform a diesel engine bench test. Particulate matter samples underwent thermogravimetric analysis to investigate the effect of lubricant additives on the particulate matter oxidation process, characteristic temperature, and activation energy. The results showed the following. Different lubricant additives result in different variation trends in the thermogravimetric curve of a particulate matter sample by varying the rotating speed and torque. When the rotating speed was stable, as the torque increased, the ignition temperature of the particulate matter of Fuel C declined rapidly during the initial stage and then increased rapidly. When the torque was stable, as the rotating speed increased, the ignition temperature of the particulate matter of Fuel C increased initially and then declined. The particulate matter of Fuel C had the lowest level of activation energy at approximately 57.89 J·mol−1. The particulate matter of Fuel A had the highest level of activation energy at approximately 74.10 J·mol−1. When the fuel has a higher cetane number, the combustion chemical reaction rate is faster and results in a more complete reaction. The active substance contact surface increases, which facilitates particulate matter oxidation.

scholarly journals Thermogravimetric Analysis of Coal Semi-Char Co-Firing with Straw in O2/CO2 Mixtures

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1421
Author(s):  
Debo Li ◽  
Ning Zhao ◽  
Yongxin Feng ◽  
Zhiwen Xie
Keyword(s):  
Activation Energy ◽  
Thermogravimetric Analysis ◽  
Ignition Temperature ◽  
Combustion Process ◽  
Stage I ◽  
Stage Iii ◽  
Combustion Behavior ◽  
O2 Concentration ◽  
Three Stages ◽  
The Individual

For coal semi-char as a by-produced of low-temperature pyrolysis, combustion for power generation is one of the effective utilization methods to realize its clean and efficient utilization. However, the coal semi-char combustion process has a difficult ignition, unstable combustion and low burnout rate. The co-firing of the semi-char with biomass under oxy-fuel conditions can improve the combustion behavior and reduce fossil CO2 emissions. In this paper, the combustion behavior of Shenhua coal semi-char (SHC) co-firing with straw (ST) in O2/CO2 mixture is investigated using thermogravimetric analysis. The results show that each curve lays between those of the individual fuels and presents three peaks (i.e., three stages). The thermogravimetric curves of SHC co-firing with ST can be divided into three stages: the volatile combustion of ST, the co-combustion of SHC and ST fixed-carbons and the SHC fixed-carbon combustion and the decomposition of the difficult pyrolytic material of ST. Blending ST into the SHC can significantly decrease the ignition temperature and improve the comprehensive combustion behavior of blended samples. In increasing the proportion of ST from 25 to 100%, the change of the blended ignition temperature is slight, but the burnout temperature decreases greatly. Kinetic parameters of combustion are calculated by using the Coats–Redfern integral method. Compared to that of stage I and stage III, the activation energy of stage II is significantly lower. As increasing blending ratio from 25% to 100%, the activation energy increases at stage I and decreases at stage III. Furthermore, the O2 concentration obviously affects stage III of 50% SHC + 50% ST, and the thermogravimetric curves at this stage are obviously shifted to the lower temperature zone as the O2 concentration increases. The activation energy of 50% SHC + 50% ST increases as the oxygen concentration increases. Besides, the activation energy shows that the combustion characteristics cannot be determined only by the activation energy obtained by the Coats–Redfern method. These findings can provide useful information for semi-char co-firing with biomass.

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.

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