The Effect of Corrosion on Crude Oil Distillation Plants

Abstract

The analysis of the corrosion phenomenon of the installations of the largest refinery in Romania confirmed the existence of its conditions, in the atmospheric distillation plants of crude oil, in the heat exchangers, and in the petrol and diesel hydrofining plants. However, the slightest effect of this phenomenon was found in the dome, the plates, and the exhaust pipes at the top of the distillation column, as well as in the reflux vessel of the atmospheric distillation plant. The main cause of the corrosion phenomenon and the increase in the corrosion areas of the material of the crude oil refining installations is the presence of hydrochloric acid, obtained after incorrect desalination (hydrolysis of calcium and magnesium chloride). To prevent this phenomenon, in laboratory conditions, we tested an antacid inhibitor (alkyl phenol) and a residual product (undistilled polyamine), with the role of supplementing the commercial inhibitor with a cheap product. The effectiveness of these additives was evaluated by introducing specimens made from the material taken from the refining column and from the reflux vessel into a solution of hydrochloric acid of various concentrations (5–15%). This solution was treated with the two corrosion inhibitors, the analysis of their effectiveness being performed at concentrations ranging between 0.05 and 0.2%. In addition, in this article, we deduced the equations of variation of the corrosion rate, depending on the working temperature of the refinery.