Análise reológica de hidrato de ciclopentano

Abstract

The work studied the rheology of cyclopentane hydrate pastes. A model fluid was developed with water, cyclopentane and oil, emulsified with Sorbitan Monooleate and Sodium Salt of Dioctyl Sulphosuccinate. The stability of the emulsion and its ability to form hydrate crystals were visualized by microscopy. Emulsion was used to form cyclopentane hydrate pastes. Cyclopentane hydrate pastes were used in rotary rheology tests with concentrations of 30% and 40% water volume. The rheological tests performed were flow curves with stress control and shear rate control, loop curves and oscillatory tests with stress, strain and frequency sweep. A large number of flow curves were performed to identify the yield point stress of the material, curves with shear stress as a function of low shear rates (10-4s-1), stress ramps as a function of material deformation and, finally, the oscillatory tests with G' and G''. The viscoelasticity of the material was also observed through flow curves that had an increase in time to steady state, then with loop curves (running in both ways) to identify the fluid's ability to restructure. In the end, with the described procedures, a high yield strength was observed for all pastes, with a degree of elasticity and partial restructuring. For the yield stresses that were found, the Herschel Bulkley model fits better the data, while G' and G'' behaved as a viscoelastic solid like in the Kelvin-Voig model.