Gas Liquid Separator CFD Simulation, ANSYS Fluent Tutorial

Description

Description

This simulation is about a Gas-Liquid Separator via ANSYS Fluent software. We perform this CFD project and investigate it by CFD analysis. A gas-liquid separator is used in several industrial applications to separate a vapor-liquid mixture. A vapor-liquid separator may be called a flash drum, break-pot, knock-out drum, or knock-out pot.

It is often called a demister when used to remove suspended water droplets from streams of air. Separation is the fluid process in which mixtures of materials in gaseous, liquid, and solid forms are separated. The crude gas entering the refinery usually contains gas, Oil, and solids and must be separated before being subjected to special operations. Oil and gas separators are one of the main gas/liquid separators used in oil/gas wells to separate gas, crude Oil, and water from the stream in the well.

Gas oil separators can be made vertically, horizontally, or spherically, but the most common type is horizontal. In this analysis, the process of separating the liquid phase from the gas using a horizontal cylindrical separator is investigated. The mixture of Oil and gas (with mass flow rates of 3kg/s and 0.15kg/s, respectively) enters the separator, and since the Oil is heavier than the gas, it settles down while the gas phase exits from the top outlet.

The geometry of the present model is drawn by Design Modeler software. The geometry of this model consists of a horizontal cylinder. It has a horizontal inlet for mixture flow and two vertical outlets for separated gas and liquid flows. The model is then meshed by ANSYS Meshing software. The model mesh is unstructured, and 356230 cells have been created.

Gas Liquid Separator Method

This simulation uses the Multi-phase model for modeling two phases of oil and hydrogen sulfide. Since the phase separation boundary is completely distinct, the Volume of Fluid (VOF) model is used.

Hydrogen sulfide is defined as the primary phase, and Oil as the secondary phase. The dispersed type in interface modeling has been used to determine the behavior at the boundary between two phases.

Gas Liquid Separator Result

After simulation, 2D and 3D contours of velocity, pressure, and mass fraction of Oil and gas are obtained. Also, the velocity vector and streamline inside the separator are obtained.

The results show that the Oil settles in the lower part of the separator. Oil goes to the bottom of the chamber due to its heaviness, and hydrogen sulfide goes to the top of the chamber due to its lightness. So it can be concluded that this separator system works well and correctly separates oil and gas phases.