Study on Gas Production and Heat Transfer Characteristics of Underground Coal Gasification with Groundwater-Related Operating and Reservoir Factor Influence
4 affiliations
- 1State Key Laboratory of Water Resource Protection and Utilization in Coal Mining , ,
- 2Xi’an Shiyou University , , , ,
- 3Taiyuan University , , , ,
- 4China University of Mining and Technology-Beijing , , ,
Abstract
Underground coal gasification (UCG) is the core technology for in situ clean conversion of deep coal resources, and one of its important differences from surface coal gasification is that the reaction process is significantly affected by groundwater. To address the insufficient consideration of groundwater effects in existing studies, the controlled retraction injection point technology-based multiphysics coupled numerical simulation model driven by partitioned reaction zone was established using COMSOL, and the reliability of the model was verified by pilot-scale tests. Then, the influences of three groundwater-related parameters, i.e., water injection flow velocity, coal seam permeability, and gasification pressure, on coal gas composition, temperature distribution, and heat-affected zone evolution were systematically investigated. The results show that the high-temperature zone and heat penetration depth are expanded by enhancing the water–gas reaction when the flow velocity is below the best-performing value of 0.55 m/min within the investigated range, and excessive heat absorption causes the maximum heat-affected depth to shrink sharply from 0.22 to 0.09 m when exceeding the threshold. Proper permeability improves gas–solid contact conditions, and the heat-affected thickness increases by over 175% at an optimal permeability of 6 mD among the tested points in this study, while excessively high permeability intensifies convective heat dissipation and reduces heat accumulation efficiency. The increase in gasification pressure significantly promotes CH4 enrichment, with the content increasing by more than 18 times as the pressure rises from atmospheric pressure to 8 MPa, and leads to the high-temperature zone and heat-affected zone being characterized by axial shrinkage and vertical widening. This study reveals the characteristics and mechanisms of heat transfer and gas production in the UCG process under the influence of groundwater-related factors, which can provide a scientific basis for the stable operation and thermal field regulation of UCG in deep coal seams.
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BibTeX
@article{liu2026study,
title = {{Study on Gas Production and Heat Transfer Characteristics of Underground Coal Gasification with Groundwater-Related Operating and Reservoir Factor Influence}},
author = {Huan Liu and Dawei Sun and Wei Guo and Jie Fang and Jingfeng Li and Junjie Shi and Shuqin Liu},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c06033},
url = {https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c06033/5455782/Study-on-Gas-Production-and-Heat-Transfer},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Study on Gas Production and Heat Transfer Characteristics of Underground Coal Gasification with Groundwater-Related Operating and Reservoir Factor Influence
AU - Huan Liu
AU - Dawei Sun
AU - Wei Guo
AU - Jie Fang
AU - Jingfeng Li
AU - Junjie Shi
AU - Shuqin Liu
PY - 2026
DA - 2026/10/21
JO - ACS Omega
DO - 10.1021/acsomega.6c06033
UR - https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c06033/5455782/Study-on-Gas-Production-and-Heat-Transfer
AB - Underground coal gasification (UCG) is the core technology for in situ clean conversion of deep coal resources, and one of its important differences from surface coal gasification is that the reaction process is significantly affected by groundwater. To address the insufficient consideration of groundwater effects in existing studies, the controlled retraction injection point technology-based multiphysics coupled numerical simulation model driven by partitioned reaction zone was established using COMSOL, and the reliability of the model was verified by pilot-scale tests. Then, the influences of three groundwater-related parameters, i.e., water injection flow velocity, coal seam permeability, and gasification pressure, on coal gas composition, temperature distribution, and heat-affected zone evolution were systematically investigated. The results show that the high-temperature zone and heat penetration depth are expanded by enhancing the water–gas reaction when the flow velocity is below the best-performing value of 0.55 m/min within the investigated range, and excessive heat absorption causes the maximum heat-affected depth to shrink sharply from 0.22 to 0.09 m when exceeding the threshold. Proper permeability improves gas–solid contact conditions, and the heat-affected thickness increases by over 175% at an optimal permeability of 6 mD among the tested points in this study, while excessively high permeability intensifies convective heat dissipation and reduces heat accumulation efficiency. The increase in gasification pressure significantly promotes CH4 enrichment, with the content increasing by more than 18 times as the pressure rises from atmospheric pressure to 8 MPa, and leads to the high-temperature zone and heat-affected zone being characterized by axial shrinkage and vertical widening. This study reveals the characteristics and mechanisms of heat transfer and gas production in the UCG process under the influence of groundwater-related factors, which can provide a scientific basis for the stable operation and thermal field regulation of UCG in deep coal seams.
SN - 2470-1343
ER -