Study on Low-Temperature Oxidation’s Endothermic Character of Coal with Comparative-Oxidation Method

2012 ◽  
Vol 577 ◽  
pp. 39-42
Author(s):  
Chang Lu ◽  
Yuan Qing Liang ◽  
Hui Hui Li
Keyword(s):  
Low Temperature ◽  
Energy Conservation ◽  
Heat Release ◽  
Release Rate ◽  
Coal Sample ◽  
Spontaneous Combustion ◽  
Storage Conditions ◽  
Equation Model ◽  
Oxidation Method ◽  
Temperature Controlled

In this paper air was passed through into one progress temperature-controlled box with coal sample and nitrogen into another as comparison during the procedure of coal’s low-temperature （10～80°C）oxidation . Draw the heating curves and heating rate curve, and equation model is built combined with energy conservation, then concludes the heat release rate of the coal samples in the air conditions. The experimental results show that the condition with air is more close to the storage conditions of coal such as transportation in reality, which is very significant to prevent the spontaneous combustion of coals

scholarly journals Influence of High Temperature Thermal Radiation on the Transition Characteristics of Coal Oxidation and Spontaneous Combustion

2021 ◽  
Vol 8 ◽  
Author(s):  
Liancong Wang ◽  
Weizhao Hu ◽  
Yuan Hu
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Thermal Radiation ◽  
Heat Release ◽  
Release Rate ◽  
Carbon Dioxide Emissions ◽  
Bituminous Coal ◽  
Spontaneous Combustion ◽  
Total Carbon ◽  
Coal Oxidation

In the goaf of the coal mine, there will be some high-temperature points before or during the fire. Under certain conditions, these high-temperature points will radiate heat to the surrounding coal in the form of thermal radiation, which, in turn, may also ignite the coal. Taking this situation into consideration, this study aims to investigate the influence of high-temperature thermal radiation on the transformation characteristics of coal oxidation and spontaneous combustion using the high-temperature thermal radiation method. The results show that an increase in thermal radiation value reduces the ignition time of coal gradually. The peak heat release rate, total heat release, peak smoke release rate, and total smoke release gradually increase. Additionally, the total carbon monoxide release reduces gradually, and the peak carbon dioxide production rate increases gradually. It is worth noting that as the heat radiation value increases, the peak value of CO production rate of lignite and bituminous coal is noted to decrease gradually, whereas that of anthracite increases gradually. The total carbon dioxide emissions of bituminous coal and anthracite increased gradually, whereas the total carbon dioxide emissions of lignite increased firstly and then decreased. This work proposes a novel method to study the coal oxidation and spontaneous combustion by a widely-recognized combustion apparatus.

Effect of Experimental Conditions on Parameters Derived from Micro Calorimeter Measurements of Coal Low-Temperature Oxidation

2013 ◽  
Vol 316-317 ◽  
pp. 850-853
Author(s):  
Xiao Xing Zhong ◽  
Yun Chen ◽  
Guo Lan Dou ◽  
De Ming Wang
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Coal Sample ◽  
Gas Flow ◽  
Low Temperature Oxidation ◽  
Experimental Conditions ◽  
Sample Mass ◽  
Temperature Oxidation ◽  
Initial Heat ◽  
Micro Calorimeter

C80 micro calorimeter was applied to investigate the initial heat release temperature and heat output at low-temperature oxidation process of Kabuliang anthracite coal under the experimental conditions of different coal sample mass, different temperature rising rates and different gas flow, and analyzed the effect of experimental conditions on test results. The results indicate that the coal sample mass and temperature rising rate affect measurement results, while there is no effect of gas flow. Under the same experimental condition, a higher temperature rising rate leads to a higher initial heat release temperature and less output of heat; The initial heat release temperature shows the trend of increase after decrease with the increase of coal sample mass. So, when micro calorimeter is used to investigate the coal low-temperature oxidation process, the experiments under the conditions of appropriate coal sample mass and the lower temperature rising rate can obtain more accurate test parameters.

Scale Modeling on the Effect of Air Velocity on Heat Release Rate in Tunnel Fire

2008 ◽  
Vol 18 (2) ◽  
pp. 111-124 ◽  
Author(s):  
C. Chen ◽  
L. Qu ◽  
Y. X. Yang ◽  
G. Q. Kang ◽  
W. K. Chow
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Air Velocity ◽  
Tunnel Fire ◽  
Scale Modeling

scholarly journals Effects of Discharge Area and Atomizing Gas Type in Full Cone Twin-Fluid Atomizer on Extinguishing Performance of Heptane Pool Fire under Two Heat Release Rate Conditions in an Enclosed Chamber

2021 ◽  
Vol 11 (7) ◽  
pp. 3247
Author(s):  
Dong Hwan Kim ◽  
Chi Young Lee ◽  
Chang Bo Oh
Keyword(s):  
Heat Release ◽  
Flow Rate ◽  
Heat Release Rate ◽  
Release Rate ◽  
Water Mist ◽  
Pool Fire ◽  
Sauter Mean Diameter ◽  
Discharge Area ◽  
Fire Extinguishing ◽  
Enclosed Chamber

In this study, the effects of discharge area and atomizing gas type in a twin-fluid atomizer on heptane pool fire-extinguishing performance were investigated under the heat release rate conditions of 1.17 and 5.23 kW in an enclosed chamber. Large and small full cone twin-fluid atomizers were prepared. Nitrogen and air were used as atomizing gases. With respect to the droplet size of water mist, as the water and air flow rates decreased and increased, respectively, the Sauter mean diameter (SMD) of the water mist decreased. The SMD of large and small atomizers were in the range of approximately 12–60 and 12–49 μm, respectively. With respect to the discharge area effect, the small atomizer exhibited a shorter extinguishing time, lower peak surface temperature, and higher minimum oxygen concentration than the large atomizer. Furthermore, it was observed that the effect of the discharge area on fire-extinguishing performance is dominant under certain flow rate conditions. With respect to the atomizing gas type effect, nitrogen and air appeared to exhibit nearly similar extinguishing times, peak surface temperatures, and minimum oxygen concentrations under most flow rate conditions. Based on the present and previous studies, it was revealed that the effect of atomizing gas type on fire-extinguishing performance is dependent on the relative positions of the discharged flow and fire source.

scholarly journals Heat release rate shaping for optimal gross indicated efficiency in a heavy-duty RCCI engine fueled with E85 and diesel

Fuel ◽  
2021 ◽  
Vol 288 ◽  
pp. 119656
Author(s):  
Robbert Willems ◽  
Frank Willems ◽  
Niels Deen ◽  
Bart Somers
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Heavy Duty ◽  
Rate Shaping

scholarly journals Experimental and Simulation of Diesel Engine Fueled with Biodiesel with Variations in Heat Loss Model

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1622
Author(s):  
Daniel Romeo Kamta Legue ◽  
Zacharie Merlin Ayissi ◽  
Mahamat Hassane Babikir ◽  
Marcel Obounou ◽  
Henri Paul Ekobena Fouda
Keyword(s):  
Heat Release ◽  
Heat Loss ◽  
Heat Release Rate ◽  
Release Rate ◽  
Diffusion Combustion ◽  
Cylinder Wall ◽  
Compression Ignition Engine ◽  
Experimental Conditions ◽  
Load Range ◽  
Combustion Phase

This study presents an experimental investigation and thermodynamic 0D modeling of the combustion of a compression-ignition engine, fueled by an alternative fuel based on neem biodiesel (B100) as well as conventional diesel (D100). The study highlights the effects of the engine load at 50%, 75% and 100% and the influence of the heat loss models proposed by Woschni, Eichelberg and Hohenberg on the variation in the cylinder pressure. The study shows that the heat loss through the cylinder wall is more pronounced during diffusion combustion regardless of the nature of the fuels tested and the load range required. The cylinder pressures when using B100 estimated at 89 bars are relatively higher than when using D100, about 3.3% greater under the same experimental conditions. It is also observed that the problem of the high pressure associated with the use of biodiesels in engines can be solved by optimizing the ignition delay. The net heat release rate remains roughly the same when using D100 and B100 at 100% load. At low loads, the D100 heat release rate is higher than B100. The investigation shows how wall heat losses are more pronounced in the diffusion combustion phase, relative to the premix phase, by presenting variations in the curves.

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