POSSIBILITY OF THE METALLIC CORRSION IN CRUDE OILS

Abstract

Metals play predominant prefaces regarding most of industrial components such as the crude oil refining industry although corrosion performed some banes. The formations of ferrous oxides, sulfides, hydroxides or certain chemical compound is the general definition regarding the corrosion. The rate of corrosion of a metal is regulated by the conditions of surrounding matter and chemical composition of such metal as well. In the current research it was expected to investigate to compare the effect of corrosive properties of two different crude oils on the rates of corrosion in seven different types of ferrous metals and their hardness. The contents of sulfur, mercaptans, organic acids and salt in both crude oils were determined by in order to XRF analyzer, titration methods and salt analyzer and also the chemical compositions of ferrous metals were determined by XRF detector. A batch of similar sized metal coupons was prepared and immersed in both crude oils separately. The corrosion rate of each metal coupon was determined by the weight loss method in order to after 15, 30 and 45 days from the immersion also the corroded surfaces were observed by the optical microscope. The concentrations of copper and ferrous in each crude oil sample were tested by atomic absorption spectroscopy (AAS) and the both initial and final hardness of each metal coupon were tested by Vicker’s hardness tester. According to the results there were observed lower corrosion rates from stainless steels while finding higher corrosion rates in other metals also significant ferrous concentrations in crude oil samples regarding carbon steels, higher corrosion rates of four types of metals in Murban crude although it was less strong regarding corrosive properties than Das Blend, formation corrosion compounds, corrosion cracks, pitting corrosion on metal surfaces and there were observed a slight reduction of hardness in each metal coupon eventually.