Application of some nonionic surfactants as corrosion inhibitors for carbon steel and pour point depressant of middle distillate fuel Oil

A series of ethoxylated nonionic surfactants, Cn E14 (n = 12,14 and 18), surfactants were prepared by reacting polyethylene glycol ( molecular weight 600) and different fatty acids: Lauric acid, Myristic acid and Oleic acid. The chemical structures of these prepared surfactants were confirmed by High Performance Liquid Chromatography (HPLC) and Proton Nuclear Magnetic Resonance (NMR) Analysis. The surface tension of the synthesized surfactants was measured at ambient temperature and the Critical Micelle Concentration (CMC) values were obtained. In addition the effectiveness of adsorption at Liquid/Air interface Гmax and minimum surface area Amin were calculated. The effect of these nonionic surfactants on the corrosion behavior of carbon steel in acidic medium 0.5M HCl was investigated. The pontentiodynamic polarization measurements showed that surfactants achieved a substantial decrease in the corrosion. The present study investigates the effect ethoxylated nonionic surfactant on depression of pour point waxy distillate fuels. Comparison of morphologies and structures of waxy crystals or aggregates in fuel oil beneficiated with and without a pour point depressant was done by micro photographic studies which show the modification in wax morphology due to additive.