On the Simulation of Multiphase Flow Containing Hydrate Particles

The article presents a mathematical model to simulate steady multiphase flow containing hydrate particles. The approach is based on the one-dimensional two-fluid model in which the two phases consist of the gas and the mixture of the liquid and hydrate particles. That is to say the hydrate particle and liquid phase are treated as pseudo-fluid. When a compositional model is used to simulate two-phase flow, it is required to couple mass, momentum, energy equations and equation of state, then the pressure and temperature and mass transfer between gas and liquid phase along the pipeline can be simulated. In the steady condition, it’s assumed that the composition of fluid is unchangeable along the pipeline and the flow can be described by pressure and temperature. In this paper, calculation method of gas-liquid two-phase flow which required a double iterative procedure of pressure and temperature respectively was improved. Liquid holdup and pressure drop were calculated by momentum equation. Enthalpy balance equation was substituted by explicit formulation of temperature calculation which meant that the loop of temperature was not required. So the calculation speed was enhanced. With strict flash calculation the following items were determined: the amount of hydrate; phase number; the location that hydrate appeared; flow rate and molar component of gas phase and liquid phase. Then thermodynamic quantities were calculated with proper relational expressions.