The need of exploiting the offshore oil reserves and reducing the equipment costs
becomes the motivation for developing new compact separation techniques. In the past
years, the development of compact separators has almost solely focused on the cyclonic
type separators made of pipes, because of their simple construction, relatively low cost
of manufacturing and being able to withstand high pressures. Considerable effort has
been put into the separator test program and qualification, and consequently notable
advances in the compact separation technique have been made. However the application
has been held back due to lacking of reliable predicting and design tools.
The objectives of this study were threefold. Firstly, an experimental study was carried
out aiming at understanding the separation process and flow behaviours in a compact
separator, named Pipe-SEP, operating at high inlet gas volume fraction (GVF).
Secondly it is to gain insight of the gas and liquid droplet flow in the compact separator
by means of Computational Fluid Dynamics (CFD) simulations. Last but not least, the
understanding and insight gained above were used to develop a comprehensive
performance predictive model, based on which, a reliable optimizing design procedure
is suggested.
An experimental study was carried out to test a 150-mm Pipe-SEP prototype with a
water-air mixture. Three distinct flow regimes inside the Pipe-SEP were identified,
namely swirled, agitated, and gas blow-by. The transition of the flow regimes was
found to be affected by inlet flow characteristics, mixture properties, geometry of the
separator, and downstream conditions. A predictive model capable of predicting the
transition of flow regimes and the separation efficiency was developed. A comparison
between the predicted result and experiment data demonstrated that the model could
serve as a design tool to support decision-making in early design stages ... [cont.]
