The Investigation of the Primary Corrosiveness of Crude Oils

Crude oil is a mixture of hydrocarbons with some kinds of trace compounds including corrosive causing compounds. Corrosion is a severe consequence regarding the industry of crude oil refining. The scope of this research was to investigate the contributions of corrosive properties of both Murban and Das Blend crude oils on the corrosion rates of seven different types of ferrous metals which are obligatory in the crude oil refining industry. The sulfur contents, Mercaptans contents, organic acid contents and salt contents of both crude oils were tested by following the standard methodologies and recommended instruments. The elemental composition of each metal coupon was tested by the XRF detector. A batch of similar sized metal coupons was prepared and those metal coupons were immersed separately in both crude oils in homogeneous way. After 15, 30 and 45 days from the immersion the corrosion rates of each type of metal were determined by the relative weight loss method with the aid of a microscopic analysis. The decayed ferrous and copper concentrations in crude oil samples were tested by the atomic absorption spectroscopy (AAS) and the variations of the initial hardness of such metal coupons due to the corrosion were tested as confirmation stages of the formation of the corrosion. There were found some relatively lower corrosion rates from stainless steels with respect to both crude oils among other metals, higher corrosive impact from salts formations of FeS, Fe2O3 and some different trace compounds, higher ferrous and copper concentrations in some of crude oil samples and slight reductions of the initial hardness of most of metal coupons due to the corrosion as the foremost results of the existing research.