CO and CO2 emissions from spontaneous heating of coal under different ventilation rates

Yuan, Liming; Smith, Alex C.

doi:10.1016/j.coal.2011.07.004

Cited by 113 publications

(38 citation statements)

References 17 publications

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“…The ratios at different initial temperatures seem to converge to the value of 0.2. This is in agreement with results from tests where ventilation rates were varied for the same coal sample (Yuan & Smith, 2011). After closer examination of the data in Fig.…”

Section: Resultssupporting

confidence: 90%

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Experimental study on CO and CO2 emissions from spontaneous heating of coals at varying temperatures and O2 concentrations

Yuan

Smith

2013

Journal of Loss Prevention in the Process Industries

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Laboratory experiments were conducted to investigate carbon monoxide (CO) and carbon dioxide (CO2) emissions from spontaneous heating of three U.S. coal samples in an isothermal oven at temperatures between 50 and 110 °C. The oxygen (O2) concentration of an oxygen/nitrogen (N2) mixture flowing through the coal sample was 3, 5, 10, 15, and 21%, respectively. The temperature at the center of the coal sample was continuously monitored, while the CO, CO2, and O2 concentrations of the exit gas were continuously measured. The results indicate that the CO and CO2 concentrations and the CO/CO2 ratio increased when the initial temperature was increased. As the inlet O2 concentration increased, the CO and CO2 concentrations increased, while the CO/CO2 ratios tended to converge to the same value. The ratio of CO/CO2 was found to be independent of coal properties, approaching a constant value of 0.2. The maximum CO production rate correlated well with the maximum coal temperature rise. The apparent order of reaction for coal oxidation was estimated to be between 0.52 and 0.72. The experimental results in this study could be used for early detection and evaluation of a spontaneous heating in underground coal mines.

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Section: Resultssupporting

confidence: 90%

“…Chakravorty and Woolf (1979) found that the absolute level of CO in the mine air, whether high or low, is not of great significance but that an increasing trend is indicative of heating. In our previous experimental study, the CO/CO 2 ratio was found to be independent of the ventilation rates (Yuan & Smith, 2011). …”

Section: Introductionmentioning

confidence: 89%

Experimental study on CO and CO2 emissions from spontaneous heating of coals at varying temperatures and O2 concentrations

Yuan

Smith

2013

Journal of Loss Prevention in the Process Industries

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“…Therefore, the concentrations of selected gases in mine atmosphere enable estimation of the temperature of coal, and assessment of the progress of the process of coal self-heating. Carbon monoxide, hydrogen, and unsaturated hydrocarbons-like ethylene, propylene, and acetylene-may be listed among the most commonly applied indicators of the self-heating process in this method [7,8].…”

Section: Introductionmentioning

confidence: 99%

Effect of Coal Grain Size on Sorption Capacity with Respect to Propylene and Acetylene

2017

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Propylene and acetylene are released to mine air with the increase in the temperature of self-heating coal. Concentrations of these gases in mine air are applied as indicators of the progress of the self-heating process. Hydrocarbons emitted from the self-ignition center are sorbed on coal, while migrating through the mine workings. Coal crushed during the mining process is characterized by a high sorption capacity, which facilitates the sorption phenomena. This results in the decrease in hydrocarbons content in mine air, and in the subsequent incorrect assessment of the development of the self-heating process. The results of the experimental study on propylene and acetylene sorption on Polish coals acquired from operating coal mines are presented in this paper. Bituminous coal is characterized by a high sorption capacity with respect to unsaturated hydrocarbons, like propylene and acetylene. The sorbed volumes depend on the grade of metamorphism, porosity, and chemical characteristics of coal. Low level of metamorphism, increased porosity, and oxygen content result in higher sorption capacity of coals. The reduction in grain size of coals also results in the increased sorption capacity with respect to hydrocarbons. The most significant increase in the volumes of sorbed propylene and acetylene with the decrease in grain class was observed for coals of low porosity, high grade of metamorphism, and low to medium sorption capacities. The 10-fold decrease in coal grain size resulted in the 3 to 6-fold increase in the volume of sorbed propylene, and 2-fold increase for acetylene. The decrease in grain size results in higher accessibility of pore structure, increased pore volume and area, and higher number of active centers interacting with hydrocarbons of dipole characteristics. For coals with low grade metamorphism, high porosity, and high sorption capacity the volumes of sorbed propylene and acetylene increased only slightly with the decrease in coal grain size.

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“…The C 2 H 4 is usually generated at a temperature higher than 100°C, which is not fit for determining the risk at low temperatures, too (Carras et al 2009;Wang et al 2003;Wang 2008). In contrast, the CO generation during coal self-heating will not be influenced by these factors (Carras et al 2009;Qi et al 2010;Wang et al 2003;Wang 2008;Yuan and Smith 2011). Therefore, CO is usually used as a good gas index for early prediction of coal spontaneous combustion.…”

Section: Effects On the Generation Of Comentioning

confidence: 91%

“…The CO 2 , H 2 O and alkane gases obtained in the testing are usually influenced by gas desorption or water evaporation (Buzek and Lnenickova 2010;Crosdale et al 2008;Küçük et al 2003;McCutcheon and Wilson 2003;Qi et al 2010;Wang et al 2003;Yuan and Smith 2011). The C 2 H 4 is usually generated at a temperature higher than 100°C, which is not fit for determining the risk at low temperatures, too (Carras et al 2009;Wang et al 2003;Wang 2008).…”

Section: Effects On the Generation Of Comentioning

confidence: 97%

Controlled-release inhibitor for preventing the spontaneous combustion of coal

Wei

et al. 2016

Nat Hazards

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The existing coal self-heating inhibitors usually have the shortcomings of short effective time and low inhibition effect. This study proposed a kind of controlled-release inhibitor and analyzed their differences in inhibition effects compared with existing inhibitors on coal self-heating. The controlled-release inhibitor is made from the synthesis of halogen inhibitors, catechin, copolymer, solvent and surfactant. The controlled-release inhibitor will not break down quickly until coal temperature reaches a value about 70°C and can continually inhibit the process of coal self-heating after a longer time. The crossing point temperature, propensity to spontaneous combustion and CO generation of coal samples processed by different inhibition methods were tested separately based on an oxidation dynamic method. The results show that the controlled-release inhibitor can inhibit the coal self-heating more effectively for a longer time than existing halogen inhibitors. This study provides a new method for more efficient prevention of coal spontaneous combustion.

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CO and CO2 emissions from spontaneous heating of coal under different ventilation rates

Cited by 113 publications

References 17 publications

Experimental study on CO and CO2 emissions from spontaneous heating of coals at varying temperatures and O2 concentrations

Experimental study on CO and CO2 emissions from spontaneous heating of coals at varying temperatures and O2 concentrations

Effect of Coal Grain Size on Sorption Capacity with Respect to Propylene and Acetylene

Controlled-release inhibitor for preventing the spontaneous combustion of coal

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