Effect of crude oil on the rate of diffusion-controlled corrosion in pipelines under turbulent flow conditions

The present work aimed to investigate the effect of crude oil on the rate of diffusion-controlled corrosion of copper pipeline in acidified dichromate under fully developed flow. To achieve this goal, various parameters were investigated, such as crude oil percentage volume (%), flow physical properties, active height of the copper pipeline, flow velocity, and the presence of Triton X-100. The results of our study revealed that the rate of copper pipeline inner-wall corrosion increases with the increase of crude oil percentage volume and flow velocity. On the other hand, the active height of copper pipeline has no significant effect on the corrosion rate. In addition, the presence of crude oil and Triton has a synergistic effect on retarding the corrosion rate. The inhibition efficiency of Triton X-100 varied from 4.4% to 41.3% depending on its concentration and flow velocity. Polarization curves indicated that the corrosion kinetics is diffusion controlled in acidified dichromate and in the presence of crude oil and Triton X-100. However, the corrosion kinetics is mixed controlled in the presence of acidified dichromate and crude oil. Correlation of the present mass transfer data using dimensionless analysis led to the following dimensionless equation: Sh= 0.58Re(0.5)Sc(0.33), with the conditions 677<Sc<1490 and 3699<Re<30,874. The present work highlighted the practical importance of the present mass transfer correlation in the design and protection against corrosion of pipelines due to crude oil transportation.