Molecular dynamics insights into wax formation—How polymeric inhibitors shape crude oil flow

Molecular-level interactions between polymeric inhibitors and wax crystals are essential for mitigating wax deposition in crude oils, a major operational and environmental challenge. This study investigates the mechanisms by which specific inhibitors target wax crystals to prevent aggregation. Extracted wax and inhibitor were characterized using gas chromatography, X-ray diffraction, and spectroscopy to determine the molecular structures. The wax primarily comprised of straight-chain n C 28 alkanes, while the inhibitor was an ethylene/vinyl acetate copolymer. Rheological tests demonstrated a reduced gelation point upon inhibitor addition. Molecular dynamics (MD) simulations, performed using the COMPASS II force field, revealed interactions at the molecular level. Structural validation of molecules was done through comparative analysis of the experimental infrared and simulated vibrational analysis spectra whereas that of the rhombohedral wax crystal was achieved using the Pawley method, yielding a Profile R -factor of 9.26%. Morphological studies revealed five symmetrically unique facets, with the (110) plane being the fastest-growing due to its inter-planar distance and attachment energy (−157.25 kcal/mol). Adsorption energy calculations (−180 kcal/mol) confirmed that the inhibitor effectively disrupted crystal growth on the surface by adsorbing its polar section onto the wax surface while repelling the non-polar groups, thereby reducing wax aggregation.