Study on the characteristics and mechanism of DL-malic acid in inhibiting spontaneous combustion of lignite and bituminous coal

Fuel ◽  
2022 ◽  
Vol 308 ◽  
pp. 122012
Author(s):  
Wei Lu ◽  
Xiaolei Sun ◽  
Liyang Gao ◽  
Xiangming Hu ◽  
Haizhou Song ◽  
...  
2020 ◽  
Author(s):  
Seok Un Park ◽  
Jae Kwan Kim ◽  
Dong Ik Shin

Abstract In this study, we examined the physical chemistry, fuel characteristics and combustion reactivity of high carbon ash as a raw material for spontaneous combustion inhibitor in order to solve the problem of spontaneous combustion which has been often occurring in coal yard of coal-fired power plants in Korea. The high carbon ash has higher activation energy and lower frequency factor than bituminous coal, so combustion began at a relatively higher temperature than bituminous coal. In case of fly ash, the heat transfer characteristics were better than those of bottom ash and pond ash, and in case of coarse particles of fly ash, they were found to be highly applicable as a raw material for spontaneous combustion inhibitor due to their relatively high unburned carbon content. As a result of manufacturing spontaneous combustion inhibitors along with asphalt and PFAD (palm fatty acid distillate), the contact angle to water was more than 90° regardless of the mixing ratio, showing hydrophobic surface characteristics, and it was found that the hardness and viscosity of spontaneous combustion inhibitors increased as the mixing ratio of high carbon ash increased. In addition, when spontaneous combustion inhibitors manufactured were applied to coal stockpiles in coal yard at coal-fired power plants, there was little change in the internal temperature of coal stockpiles and the highest value of instantaneous increasing rate per minute was found to be lowered from 1.60°C/min to 0.061°C/min, indicating that spontaneous combustion inhibitors using high carbon coal ash had a great effect of preventing spontaneous combustion.


Fuel ◽  
2018 ◽  
Vol 216 ◽  
pp. 181-189 ◽  
Author(s):  
Quanlin Shi ◽  
Botao Qin ◽  
Hongjun Liang ◽  
Yuan Gao ◽  
Qiang Bi ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Liancong Wang ◽  
Weizhao Hu ◽  
Yuan Hu

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.


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