Use of Time Domain - NMR for the characterization of high viscosity organic systems

Abstract

The aim of this project is to develop a Nuclear Magnetic Resonance (NMR) approach with emphasis on time domain analysis to characterize dynamics and structural properties of different high viscosity organic systems with industrial interest: biopolymers gels and heavy oils. Although the two specific applications are quite different, the methodologies to be used in NMR studies are similar and/or complementary. Biopolymers gels are colloidal systems with solid character where the liquid phase is immobilized by a three-dimensional polymer network. NMR measurement such as T1, T2 and T1r relaxation, 1H multiple quantum and 1H spin diffusion will be used to investigate structural and dynamics properties in gels systems based on wheat gluten, that have unique viscoelastic properties of importance not only in food industry, but also in many other areas. The other study involves the effects of heavier compounds of petroleum, the asphaltenes, on their rheological properties such as viscosity. Asphaltenes are a complex mixture of compounds of various molecular weights and structures, including condensed aromatic rings with alkyl groups, heteroatms and metals. These compounds can affect oil production in all stages due to their tendency to aggregate, which causes increased viscosity and leads to significant economic losses. In this study, high resolution, relaxometry and multiple quantum NMR techniques will be used to study the composition and rheological properties such as viscosity of heavy oils, with particular emphasis on the rule played by asphaltenes. We seek for a correlation between the chemical composition, structural and dynamic properties on this systems.