Removal of alkaline nitride from lubricating oil by modified clays

Abstract In order to improve the removal efficiency of clays in oil refining, to explore the related factors and to clarify the removal mechanism of alkaline nitride, a series of modified clays was prepared to test removal of alkaline nitride from lubricating oil. After the addition of 1 wt.% FeCl3, the removal rate of alkaline nitride increased from 33.6% to 43.3%. Furthermore, the acidity and chlorine content did not exceed acceptable levels. The testing methods of N2 adsorption–desorption, particle-size distribution, Fourier-transform infrared spectroscopy and X-ray diffraction were conducted to verify the removal mechanism. The removal rate of alkaline nitride is mainly related to the density of Lewis acid sites. The Fourier-transform infrared spectra confirmed the existence of the complexation reaction. The basic nitrides were removed by chemical adsorption via Fe3+-complexation.