Comb-like Polyoctadecyl Acrylate (POA) Wax Inhibitor Triggers the Formation of Heterogeneous Waxy Oil Gel Deposits in a Cylindrical Couette Device

In real crude-oil pipelines, the formed wax deposits could be heterogeneous along the radial or axial directions. However, studies on this aspect are scarce. In this paper, the effect of the polyoctadecyl acrylate (POA) wax inhibitor on the wax deposition of 10 wt % model waxy oil was investigated with the aid of an in-house wax deposition device, differential scanning calorimetry test, high-temperature gas chromatography–Fourier transform infrared analysis, and microscopic observation. The results showed that adding POA in the model waxy oil greatly modifies the morphology of precipitated wax crystals, thus greatly changing the wax deposition behavior of the oil. For oil sample 1 (without POA), the precipitated wax crystals (needle-like) more easily form porous network structures, causing the formation of a thick and porous wax deposit with relatively low WAT, wax conten,t and critical carbon number (CCN). With the increase of POA concentration (oil samples 2–5), the precipitated wax crystals become more...