Coalbed methane thermodynamic extraction, as an emerging ECBM recovery method, can effectively improve gas recovery rates. And clarifying methane diffusion and migration law in coal under thermal stimulation is crucial for the selection of its process parameters. Based on laboratory methane adsorption-release experiments, the evolution law of methane diffusion characteristics with temperature and pressure was studied, and the control mechanism of heat-dependent methane diffusion behavior was explored. The results show that both thermal stimulation and high adsorption pressure accelerated the methane diffusion rate in coal. Adsorption pressure had little effect on methane diffusion percentage, but thermal stimulation promoted a significant increase in diffusion percentage and improved the net methane yield. The influence mechanisms of adsorption pressure and thermal stimulation on methane diffusion characteristics are elucidated in relation to the amount and proportion of methane-activated molecules in the diffusion process. The constant diffusion coefficient of methane is heat-dependent, based on which a diffusion model is derived to accurately predict the methane release process in coal. Additionally, temperature has a more important effect on transient diffusion coefficient than pressure. Thermal stimulation leads to a net increase rather than a decrease in diffusion coefficient in the early diffusion stages and can also accelerate the attenuation of diffusion coefficient, with this intensifying effect becoming more pronounced at higher temperatures. The research results can provide some reference for the determination of coal seam gas content and the selection of heat injection process parameters.
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http://dx.doi.org/10.1007/s11356-024-34896-1 | DOI Listing |
Environ Res
January 2025
School of Materials and Chemistry, University of Shanghai for Science and Technology, Shanghai 200093, China. Electronic address:
The pressing necessity to mitigate climate change and decrease greenhouse gas emissions has driven the advancement of heterostructure-based photocatalysts for effective CO₂ reduction. This study introduces a novel heterojunction photocatalyst formed by integrating potassium-doped polymeric carbon nitride (KPCN) with metallic Zn₃N₂, synthesized via a microwave-assisted molten salt method. The resulting Schottky contact effectively suppresses the reverse diffusion of electrons, achieving spatial separation of photogenerated charges and prolonging their lifetime, which significantly enhances photocatalytic activity and efficiency.
View Article and Find Full Text PDFSci Rep
December 2024
College of Safety Engineering, Chongqing University of Science and Technology, Chongqing, 401331, China.
In order to promote low-carbon sustainable development in the ecological environment and improve the efficiency of hydrogen and natural gas energy utilization, this project carried out research on the explosive effects of different thicknesses of ordered porous media on the hydrogen-methane gas mixture. A detailed discussion was conducted based on the critical quenching hydrogen blending ratio under the thicknesses of 50 mm and 60 mm of ordered porous media. The results indicate that the critical quenching hydrogen blending ratio is 9% for a thickness of 50 mm and 20% for a thickness of 60 mm, indicating that greater thickness enhances flame suppression capabilities.
View Article and Find Full Text PDFEnviron Monit Assess
December 2024
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Xiangshan, Beijing, 100093, China.
Methane (CH) processes and fluxes have been widely investigated in low-latitude tropical wetlands and high-latitude boreal peatlands. In the mid-latitude Mongolia Plateau, however, CH processes and fluxes have been less studied, particularly in riverine wetlands. In this study, in situ experiments were conducted in the riverine sandy wetlands of the Mongolia Plateau to gain a better understanding of CH emissions and their influencing mechanisms.
View Article and Find Full Text PDFJ Environ Manage
December 2024
Department of Ecology, Radboud Institute for Biological and Environmental Sciences, Radboud University, Nijmegen, the Netherlands.
Recent studies indicate that greenhouse gas (GHG) emissions from agricultural drainage ditches can be significant on a per-unit area basis, but spatiotemporal investigations are still limited. Additionally, the impact of dredging - a common management in such environments - on ditch GHG emissions is largely unknown. This study presents year-round GHG emissions from nine ditches on a dairy farm in the center of the Netherlands, where each year, approximately half of the ditches are dredged in alternating cycles.
View Article and Find Full Text PDFJ Chem Eng Data
December 2024
Institute for Materials and Processes, School of Engineering, The University of Edinburgh, Edinburgh EH9 3FB, Scotland, U.K.
A comprehensive quantitative grasp of methane (CH), nitrogen (N), and their mixture's adsorption and diffusion in MIL-101(Cr) is crucial for wide and important applications, e.g., natural gas upgrading and coal-mine methane capturing.
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