Wax Deposition Inhibition Performance of a PAO/Pour Point Depressant/SiO2-IL Ternary System in High-Wax-Content Model Oil

Wax deposition in high-wax-content oils can impair low-temperature transport, while single flow improvers often provide limited control over the overall deposition process. To improve wax deposition inhibition through functional complementarity, a PAO/pour point depressant (PPD)/SiO2-IL ternary formulation was developed. Alkyl-imidazolium-functionalized SiO2 materials with C2, C4, and C6 chains were prepared and characterized by FT-IR, TGA, and SEM. Wax deposition was evaluated using a static cold-finger method at a bulk-oil temperature of 55 °C and a cold-finger temperature of 25 °C. A model oil containing 20 wt% paraffin and a deposition time of 2 h was selected for formulation evaluation. The binary formulation containing 40 ppm PAO and 100 ppm JN-3 achieved a wax deposition inhibition efficiency of 67.53%. Among the SiO2-IL materials, Sil@HIL (C6) showed comparatively high performance, with its highest inhibition at 200 ppm within the tested dosage range. The resulting ternary formulation achieved 77.49% inhibition, which is 9.96 percentage points above the binary formulation. These findings indicate that incorporating Sil@HIL into the PAO/JN-3 formulation further improves wax deposition inhibition under the investigated static conditions.