Multiphase Desander – Pressure Drop and Fluid Throughput (B-FSM087)
Note: The hydraulic pressure drop model for a multiphase desander builds on the methodology presented for a liquid desander as detailed in post B-FSM-060. I recommend strongly to read the previous material first.
The first step in modeling a multiphase desander is to determine the operating pressure drop. The multiphase fluid throughput relationship is built from the hydraulic and pneumatic cyclone models. These are listed below.
- Based on Plitt liquid cyclone model (reference below)
- Use a geometric k-factor based on cyclone geometry
- Modified for free-gas content using a dimensionless factor (G) based on gas:liquid ratio
- Both k and G factors are determined in the laboratory for the geometric cyclone model
- Pressure drop minor factors include fluid viscosity and solids concentration
- Used for liquid-dominant operating regime
- Based on Stairmand relationship (referenced in Benitez below)
- Incorporates specific geometric constants for the cyclone model
- Uses “heavy” gas – which is fluid mixture density and viscosity
- Used for gas-dominant operating regime
An example of these models will be presented after the separation size and collection efficiency models are presented in the next article.
- Benítez, J. 1993. Process Engineering and Design for Air Pollution Control. Upper Saddle River, NJ: PTR Prentice Hall.
- Plitt, L.R. 1976. A Mathematical Model of the Hydrocyclone Classifier. CIM Bulletin 69 (776): 114-123.
- Rawlins, C.H. 2017. “Separating Solids First – Design and Operation of the Multiphase Desander”, paper 185658-MS presented at the SPE Western Regional Meeting, Bakersfield, CA, 23-27 April.