Study On Flow Characteristics Of Natural Gas Hydrate Slurry

The study on hydrate slurry flow characteristics is the fundamental basis for hydrate slurry transportation research. The investigation on flow characters also offers technological support for stabilized slurry transportation in practical field and serves as technological basis for feasibility study of hydrate slurry as a new method of gas storage and transportation.This thesis puts forward several models to offer prediction, simulation results of hydrate slurry physical characteristics and slurry flow characteristics in horizontal pipes.The models are developed on hydrate formation process analysis and slurry flow characteristic simplification, thesis models are of great value for hydrate slurry preparation and prediction of slurry flow characteristics.Firstly, the physical characteristics and relevant calculation methods for hydrate slurry are reviewed, an experiment scheme was designed to verify the accuracy of those methods. Then two models were proposed based on two common hydrate slurry preparation process: pressure-constant process and volume-constant process, to calculate system parameters at equilibrium state separately, also, a series of experiments were carried out to verify these two models. Furthermore, a flow model about hydrate slurry flow characters was put forward by the author on the basis of conventional two-layer model of solid-liquid flow. The new model which considered rheology of hydrate slurry and force equilibrium was then simplified based on flow pattern transforming process analysis, a critical velocity of steady flow was then proposed based on the model. By solving the equations, the flow characteristics including flow pattern, critical velocity for stabilized flow, solid phase volume concentration profile and pressure drop gradient etc., were obtained. A series of comparison with experimental results confirms that the new model provides accurate prediction over wide range of application. Finally, numerical simulation of hydrate slurry flow was carried out base on theories of hydrate particle diameter and slurry viscosity, Compared with former simulations, the consideration of new models gives better description of hydrate particle diameter variation and effective viscosity profile.