Studying the micromechanism of water injection to suppress coal and gas protrusion

To explore the adsorption mechanism of CH4 and H2O molecules on the surface of low-rank coal (LRC) from the microscopic point of view, the electrostatic potential and frontier orbitals of each oxygen-containing functional group (OFGs) in LRC and adsorbent molecule, the adsorption energy, and Mullike...

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Main Authors: Jiayun Lun, Haoliang Han, Xinliang Fang, Junling Ding, Nan Jia
Format: Article
Language:English
Published: AIP Publishing LLC 2022-12-01
Series:AIP Advances
Online Access:http://dx.doi.org/10.1063/5.0130863
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author Jiayun Lun
Haoliang Han
Xinliang Fang
Junling Ding
Nan Jia
author_facet Jiayun Lun
Haoliang Han
Xinliang Fang
Junling Ding
Nan Jia
author_sort Jiayun Lun
collection DOAJ
description To explore the adsorption mechanism of CH4 and H2O molecules on the surface of low-rank coal (LRC) from the microscopic point of view, the electrostatic potential and frontier orbitals of each oxygen-containing functional group (OFGs) in LRC and adsorbent molecule, the adsorption energy, and Mulliken charge layout of CH4 molecules and H2O molecules with OFGs in LRC were investigated by density functional theory (DFT) simulation method. The results of DFT calculations showed that the order of adsorption strength of CH4 molecules on different OFGs was OCH3–LRC (-9.643 kJ/mol) > C=O–LRC (−8.625 kJ/mol) > OH–LRC (−7.241 kJ/mol) > COOH–LRC (−6.194 kJ/mol), which were all smaller than that of the C–LRC model without functionalization (−10.749 kJ/mol). The presence of OFGs reduces the adsorption strength of CH4 molecules on the surface of LRC. The order of strength of adsorption of H2O molecules on different OFGs was COOH–LRC (−69.836 kJ/mol) > OH−LRC (−46.442 kJ/mol) > C=O–LRC (−42.848 kJ/mol) > OCH3–LRC (−33.079 kJ/mol), and they were all greater than that of the C–LRC model without functionalization (−32.572 kJ/mol). The presence of OFGs improves the adsorption strength of H2O molecules on the surface of LRC. Both the LRC model modified with OFGs and the non-functionalized C–LRC model showed stronger adsorption of H2O molecules compared to that of CH4 molecules. Therefore, coal seam water injection can reduce the amount of gas gushing and mitigate coal seam gas protrusion.
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spelling doaj.art-dd536a600a554c9aaa747fff6d3efc812023-01-19T16:47:09ZengAIP Publishing LLCAIP Advances2158-32262022-12-011212125014125014-810.1063/5.0130863Studying the micromechanism of water injection to suppress coal and gas protrusionJiayun Lun0Haoliang Han1Xinliang Fang2Junling Ding3Nan Jia4Information Institute of the Ministry of Emergency Management of the PRC, Beijing 100029, ChinaInformation Institute of the Ministry of Emergency Management of the PRC, Beijing 100029, ChinaSchool of Emergency Management and Safety Engineering, China University of Mining and Technology (Beijing), Beijing 100083, ChinaDepartment of Basic Sciences, Dalian Institute of Science and Technology, Dalian, Liaoning 116052, ChinaChina Coal Technology & Engineering Group Shenyang Research Institute, Fushun, Liaoning 113122, ChinaTo explore the adsorption mechanism of CH4 and H2O molecules on the surface of low-rank coal (LRC) from the microscopic point of view, the electrostatic potential and frontier orbitals of each oxygen-containing functional group (OFGs) in LRC and adsorbent molecule, the adsorption energy, and Mulliken charge layout of CH4 molecules and H2O molecules with OFGs in LRC were investigated by density functional theory (DFT) simulation method. The results of DFT calculations showed that the order of adsorption strength of CH4 molecules on different OFGs was OCH3–LRC (-9.643 kJ/mol) > C=O–LRC (−8.625 kJ/mol) > OH–LRC (−7.241 kJ/mol) > COOH–LRC (−6.194 kJ/mol), which were all smaller than that of the C–LRC model without functionalization (−10.749 kJ/mol). The presence of OFGs reduces the adsorption strength of CH4 molecules on the surface of LRC. The order of strength of adsorption of H2O molecules on different OFGs was COOH–LRC (−69.836 kJ/mol) > OH−LRC (−46.442 kJ/mol) > C=O–LRC (−42.848 kJ/mol) > OCH3–LRC (−33.079 kJ/mol), and they were all greater than that of the C–LRC model without functionalization (−32.572 kJ/mol). The presence of OFGs improves the adsorption strength of H2O molecules on the surface of LRC. Both the LRC model modified with OFGs and the non-functionalized C–LRC model showed stronger adsorption of H2O molecules compared to that of CH4 molecules. Therefore, coal seam water injection can reduce the amount of gas gushing and mitigate coal seam gas protrusion.http://dx.doi.org/10.1063/5.0130863
spellingShingle Jiayun Lun
Haoliang Han
Xinliang Fang
Junling Ding
Nan Jia
Studying the micromechanism of water injection to suppress coal and gas protrusion
AIP Advances
title Studying the micromechanism of water injection to suppress coal and gas protrusion
title_full Studying the micromechanism of water injection to suppress coal and gas protrusion
title_fullStr Studying the micromechanism of water injection to suppress coal and gas protrusion
title_full_unstemmed Studying the micromechanism of water injection to suppress coal and gas protrusion
title_short Studying the micromechanism of water injection to suppress coal and gas protrusion
title_sort studying the micromechanism of water injection to suppress coal and gas protrusion
url http://dx.doi.org/10.1063/5.0130863
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AT xinliangfang studyingthemicromechanismofwaterinjectiontosuppresscoalandgasprotrusion
AT junlingding studyingthemicromechanismofwaterinjectiontosuppresscoalandgasprotrusion
AT nanjia studyingthemicromechanismofwaterinjectiontosuppresscoalandgasprotrusion