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Energies 2018, 11(2), 428; doi:10.3390/en11020428

Experimental Enrichment of Low-Concentration Ventilation Air Methane in Free Diffusion Conditions

School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China
Department of Civil Engineering, Monash University, Melbourne, VIC 3800, Australia
School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, China
Authors to whom correspondence should be addressed.
Received: 16 January 2018 / Revised: 7 February 2018 / Accepted: 9 February 2018 / Published: 13 February 2018
(This article belongs to the Section Energy Sources)
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The massive emission of low concentrations (≤0.5%) of methane (CH4) from ventilation roadways results in resource waste and environmental pollution. To mitigate these emissions, an enrichment tower for low-concentration methane is designed, and segregation and non-segregation experiments are conducted. The results reveal that stable concentrations of methane under segregation and non-segregation states in the enrichment tower gradually increase with height, with a maximum methane concentration of 0.64% and 0.54%, respectively. This shows that the methane enrichment effect in free diffusion conditions is more significant under the segregation state than under the non-segregation state. The stable concentration of methane in the middle and upper sections of the enrichment tower shows an increasing trend. However, the stable concentration of methane in the lower section of the enrichment tower has an increasing trend (less than 0.50%). According to the methane molecule Boltzmann distribution law, methane concentration enrichment decreases with height, and the conversion of the methane from the segregated to non-segregated is irreversible. Consequently, industrial applications of methane enrichment from buoyant forces are not feasible for low concentrations of methane. View Full-Text
Keywords: return air in mine; low-concentration methane; diffusion enrichment; non-segregation return air in mine; low-concentration methane; diffusion enrichment; non-segregation

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Wang, W.; Wang, H.; Li, H.; Li, D.; Li, H.; Li, Z. Experimental Enrichment of Low-Concentration Ventilation Air Methane in Free Diffusion Conditions. Energies 2018, 11, 428.

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