Progress achieved in the application of hydrate technology to coal seam development: A review

The management of coalbed firedamp, as well as the separation of coalbed methane (CBM), is critical for ensuring safe mining operations and promoting the exploitation of environmentally sustainable mining practices. Hydrate technology utilizes the properties of water molecules to encapsulate gas molecules under specific temperature and pressure conditions, thus achieving efficient solidification of gas, which prevents coal and gas outbursts and enables selective separation and purification of methane (CH4). This article begins by reviewing the thermodynamic and kinetic characteristics associated with hydrate formation from firedamp/CBM within coal seams, including the underlying mechanisms involved. Furthermore, it discusses the potential occurrence of naturally occurring hydrates within coal seams and their relationship to the characteristics of those seams. Following this, the feasibility of hydrate-based coal and gas outburst prevention is analyzed. Recent advancements in the permeability and mechanical properties of hydrate-bearing coal are summarized, highlighting its unique advantages in reducing gas pressure and mitigating the risk of outbursts. Additionally, the potential mechanisms and effectiveness of hydrate-based CBM separation using traditional surfactants, biological additives, amino acids, nanomaterials, and emulsions are critically evaluated. Finally, this study identifies the challenges and prospects associated with hydrate technology in managing coal and gas outbursts and separating CBM, particularly regarding the prevalent challenge of hydrate stability. The conclusion emphasizes that future interdisciplinary collaborative innovations are essential for translating hydrate technology from laboratory research into practical applications in coal seam development. Such advancements are anticipated to furnish both theoretical and technical support for coal mine safety and resource utilization.