~1H low- and high-field NMR study of the effects of plasma treatment on the oil and water fractions in crude heavy oil

摘要

The chemical and physical properties of a Brazilian heavy oil submitted to plasma treatment were investigated by ~1H low- and high-field nuclear magnetic resonance (NMR) combined to the characterization of Theological properties, thermogravimetry and measurement of basic sediments and water (BSW) content. The crude oil was treated in a dielectric barrier discharge plasma reactor, using natural gas, CO_2 or H_2 as working gas. The results indicated a large drop in the water content of the plasma-treated samples as compared to the crude oil, giving rise to a reduction in the viscosity. No significant chemical change was produced in the oil portion itself, as observed by ~1H NMR. The water contents determined by ~1H low-field NMR analyses agreed well with those obtained by BSW, indicating the low-field NMR methods as a useful tool for following the effects of plasma treatments on heavy oils, allowing the separation of the effects caused on the water and oil fractions.