Structural–Response Consistency Evaluation of a Jiulong Coking Coal Molecular Model Based on Multi-Characterization Constraints

Abstract The evaluation of coal molecular models commonly relies on individual criteria, such as structural parameter matching, density agreement, or consistency in adsorption behavior. However, these indicators are usually considered independently, and a unified quantitative framework for integrating different evaluation dimensions is still lacking. In this study, an average organic molecular model of Jiulong (JL) coking coal was constructed based on ultimate analysis, 13C NMR, FTIR, and XPS characterization, and a structure–response consistency evaluation framework was established by integrating structural constraints and multiresponse analysis. Based on aromatic carbon fraction, XBP, C–O/C═O ratio, and pyrrolic N/pyridinic N ratio, the molecular formula of the JL coal model was determined as C205H144O30N4. Five indices, including the structural constraint consistency index (SCI), density consistency index (DCI), adsorption response consistency index (ACI), dynamic wetting trajectory consistency index (WCI), and multiresponse consistency index (MCVI), were proposed to quantify structural constraint satisfaction and response consistency. The results indicate that the model effectively retains the structural features derived from multicharacterization, with an (SCI) value of 0.981. The simulated density of the aggregate model was 1.22 g/cm3, and the relative deviation from the mineral-corrected equivalent density of the organic framework decreased to 2.24%, corresponding to a (DCI) value of 0.978. The simulated and experimental CO2 adsorption behaviors exhibited a similar overall trend, with an (ACI) value of 0.807. However, deviations were observed around Pc ≈ 0.03 MPa, indicating that the model reasonably describes micropore-dominated adsorption but does not fully represent pore relaxation, mineral–coal interactions, and heterogeneous adsorption sites at relatively higher pressures. Both experimental and simulated contact angles decreased during wetting, yielding a (WCI) value of 0.682, suggesting that interfacial wettability is more sensitive to polar site distribution, surface roughness, and mineral components. The (MCVI) value of 0.862 indicates an overall structure–response consistency of the model, although differences exist among different response dimensions. This study provides a quantitative framework for evaluating the consistency and applicability of coal molecular models.