Effect of pressure and salinity on the performance of a gas-liquid separator—a preliminary study
The separation of liquid from gas during the initial stages of the separation process is very important in increasing well productivity. This is why the design of an efficient and compact gas-liquid separator has received much attention from academic researchers as well as field operators. They all state the necessity of compact design in deploying separators offshore (and potentially subsea) to enhance the recovery of gas wells. This investigation describes an experimental and computational fluid dynamics (CFD) modelling of a laboratory-scale compact gas-liquid separator designed by CSIRO. The separator consists of two concentric pipes with a swirl tube in the annular space between the pipes. The gas-liquid mixture comes from the tangential side inlet, and the system works with a combination of gravity and centrifugal forces to achieve a highly efficient gas-liquid separation. The effect of pressure and salinity on the performance of the gas-liquid CSIRO’s separation technology (CS-T) separator is investigated in this paper. The performance of the separator is visually established by observing the liquid carry over (LCO) regime in which liquid is carried out in the gas stream. The liquid and gas-flow rate at which the LCO is observed defines the upper operational range of the separator. Air-water mixture is used for both experimental and CFD investigations. The performance is evaluated at 1, 2, 5, 10 and 12 barg pressure. The upper operational range decreases with increases in pressure. For higher pressure (10 and 12 barg), the LCO curve was nearly vertical, which indicates no change in gas-flow rate with the increase in water flow rate. Salinity does not affect the performance of the CS-T separator. The CFD results are used to visualise the continuous LCO and to understand the physics and mechanism of LCO.