Coal water slurry (CWS), as an environmentally friendly clean coal-based fuel, its system is mainly composed of pulverized coal, aqueous medium and functional additives. Supported by the advantage of China's coal resource endowment, coal-water slurry technology has developed into a fundamental, economic and clean energy solution to replace oil and gas fuels [1]. Relevant studies have shown that compared with traditional coal combustion methods, the particulate matter emissions of the combustion products of coal water slurry are significantly reduced, and it has the advantage of suppressing the generation of harmful gases, demonstrating considerable application potential in the fields of industrial boilers and kilns [2,3]. It is important to highlight that, owing to the unique physicochemical characteristics of low-rank coal (e.g., poor surface floatability, abundant oxygen-containing functional groups, high inherent moisture content, and a significant proportion of volatile matter), the coal-water slurry derived from it typically encounters technical challenges, including inadequate system stability, low slurry concentration, excessively high apparent viscosity, and suboptimal rheological properties. Studies have demonstrated that the incorporation of surfactants can significantly enhance the surface hydrophobicity of low-rank coal particles. Meanwhile, specialized dispersants can improve the rheological properties of slurries by leveraging steric hindrance and electrostatic repulsion effects. Nevertheless, a comprehensive understanding of the microscopic mechanisms underlying the interaction of surfactants at the coal-water interface remains limited.

In recent years, molecular dynamics simulation technology has emerged as a crucial tool in the study of energy materials, owing to its distinctive ability to uncover dynamic behaviors and thermodynamic properties at the molecular level [4]. Compared with conventional experimental characterization methods, this technique enables the analysis of the adsorption kinetics of surfactant molecules on the coal surface at the atomic level. Through quantitative evaluation of critical parameters, the interaction mechanism between surfactant molecules and the coal matrix can be elucidated in greater depth. It is particularly noteworthy that the collaborative research strategy, which integrates experimental investigations with molecular simulations, not only validates the interfacial regulation mechanisms of surfactants from multiple perspectives but also provides theoretical guidance for the efficient and environmentally friendly utilization of low-rank coal. This approach holds significant engineering practical value for promoting the large-scale exploitation of low-rank coal resources in China.

This manuscript aims to clarify the microscopic dispersion mechanisms of four types of surfactants, namely nonionic, cationic, amphoteric and anionic, in water-coal slurry by using a molecular dynamics simulation system. Optimize the key molecular dynamic parameters of the coal-surfactant-water system (such as force field selection, simulation box size, etc.); In view of the current limitations of molecular dynamics simulation (such as model simplification and high computational cost), a solution integrating machine learning and multi-scale simulation is proposed; Establish a theoretical framework for the rational design of high-performance and environmentally friendly water-coal slurry dispersants.