A new method to estimate the partition of corrosion inhibitors

Abstract

The partitioning coefficient of the R12Na corrosion inhibitor is determined by relating its concentration in the water phase (C W) to the expected theoretical concentration (C i,T) due to a re-concentration phenomenon after the mixing stage. Partition experiments were performed by varying the water cut in brine-kerosene mixtures, temperature, and the inhibitor concentration using NACE 1D182 brine as a water phase and ultraviolet-visible spectrophotometry. The partition results varied from 37.81 to 43.75 %, 36.68 to 61.23 %, and 40.29 to 56.47 % at 40 °C, 60 °C, and 80 °C, respectively, indicating that R12Na is a water soluble inhibitor and dispersible in the organic phase. Likewise, the partition results varied from 41.69 to 44.04 % in the presence of 20, 50, and 100 mg L−1 of the inhibitor, using a ratio of 80–20 vol% WP–OP and 60 °C. Furthermore, making the same considerations, the partition of different corrosion inhibitors reported in the literature was evaluated, supporting its determination, the latter is of great importance for dosing corrosion inhibitors in the oilfield industry.