Evaluation of Corrosion Inhibition of Carbon Steel in Crude Oil by Using Different Green Corrosion Inhibitors and Various Rotation Speeds

Abstract

Corrosion is a major problem in the petroleum industry, which often occurs to crude oil production equipment and to petroleum product transportation pipelines as well. In order to protect these parts from corrosion, much small quantities of inhibitors are constantly injected, which gradually formulate a fluffy layer of inhibitor over the metal surface so as to protect it from corrosion. Recently, the impact of corrosion inhibitors on the environment has been raising more attention and concern. New regulations related to environment have been designated, imposing a change in the use of toxic chemicals to the utilization of the so-called “green chemicals”. Experiments on carbon steel corrosion protection have been conducted in a medium of crude oil has an API gravity of 30.6 by using different concentrations, ranging between 100 – 400 ppm of different green inhibitors such as corn oil, sunflower oil, flaxseed oil and castor oil with a different rotation speeds, namely, 0, 500, 1250 and 2000 rpm. The weight loss outcomes have showed that the rate of carbon steel corrosion in the crude oil decreases with the rise of inhibitors’ concentration, while corresponds with the increase of the rotational speed. In addition, it was found that the maximum inhibition efficiency achieved for the inhibitors corn oil, sunflower oil, flaxseed oil and castor oil in crude oil was using a concentration of 400 ppm, a rotation speed of 0 rpm and an ambient temperature (25 °C) is 41.85%, 50.76%, 63.55% and 92.63%, respectively.