Effects of Geometry, Temperature, and Inlet Conditions on the Flow Split in Spheroids Manifold

Abstract

A Computational Fluid Dynamics CFD study was conducted on the mal-distribution problem occurring within the pipe network upstream of pairs of spheroids gravity separators used in the oil industry. The series of simulations were conducted using the Euler-Euler multiphase and the k-e turbulence models. The cases studied reflect different scenarios of oil production capacity in addition to the effect of seasonal variations of temperature increasing from 10?C during winter to 24?C during summer. The inlet conditions were varied so that they permitted to elucidate the effects of the flow rates and temperatures at the inlet of the piping network on the multiphase flow behavior and hence the mal-distribution within the pairs of spheroids considered. Two manifold configurations were taken from real installations in the oil industry. They contain T-junctions with different orientations. Averages of 2.2 million computational cells were generated for each case studied. The main source of mal-distribution was found to be the sequence and cascading of the existing T-junctions inside the pipe network that are known to act like phase separators. A mal-distribution between the risers of each spheroid was, also, noticed. The relatively large number of T-junctions used, as well as the structure of the downstream piping network employed, led to complex multiphase flow behavior. The mal-distribution, generated by different flow scenarios, were less than 12 for the manifold referred to as Configuration 1. Configuration 2 caused more noticeable mal-distribution reaching up to 40%. The symmetry of the piping networks and the arrangement of the T-junctions were found to be a key parameter among the causes of the mal-distribution