Numerical Simulation of Hydrate Transport in Natural Gas Pipeline

Abstract

Accurate modeling of hydrate transportation in natural gas pipelines is becoming increasingly important in the design and operation of offshore production facilities. The dynamics involved in the formation of hydrate particles and in its transportation are governed by the multiphase hydrodynamics equations ensuing from the balance of mass, momentum, and energy. In this study, a two-fluid model is solved to characterize particulate transportation. The numerical algorithm employed is stable and robust and it is based on higher-order schemes. This is necessary since the governing equations describing the simultaneous flow of gas and solid particles are hyperbolic and, thus, admit discontinuities. Specialized higher-order schemes provide a viable approach for efficient frontal tracking of continuity waves in particular. Several simulation experiments that can facilitate thorough understanding of the design and maintenance of pipelines susceptible to hydrate formation are presented.

Revisiting low-fidelity two-fluid models for gas–solids transport

“…(24). Therefore, in order to remain within the domain of dependence in every block at each time step, the following limitation are applied: (26) where (λ n ) max is the maximum λ across the spatial domain at t n and the Courant-Friedrichs-Lewy (C F L) number [40] is a dimensionless quantity. The CFL number may be regarded as the ratio of (λ n ) max to the grid speed ( x/ t) and determined by the choice of numerical scheme employed in approximating the numerical fluxes as well as the choice of numerical integrator in the case of the semi-discrete formulation of Eq.…”

“…Ibraheem and Adewumi [26] also studied two-phase gas-solids transport for the initiation stage of hydrate formation and transport in natural gas pipelines. They utilized a conservative finite volume scheme and applied a Roe-type approximate Riemann solver using the set of Roe-Pike averages they had presented.…”