What Is the Flash Drum Vapor Mist Wire-Mesh Demister Pad Sizing Calculator?
A wire-mesh demister pad coalesces fine aerosol liquid droplets from an ascending gas stream, preventing downstream liquid carryover.
How Does the Flash Drum Vapor Mist Wire-Mesh Demister Pad Sizing Calculator Work?
Calculates maximum gas velocity balancing gravitational settling against aerodynamic drag; applies a 75% derating safety margin to size pad area.
Flash Drum Vapor Mist Wire-Mesh Demister Pad Sizing Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
V_{ ext{max}} = K sqrt{ rac{
ho_l -
ho_v}{
ho_v}}, quad A_{ ext{pad}} = rac{Q_v}{0.75 V_{ ext{max}}}, quad D_{ ext{vessel}} = sqrt{ rac{4 A}{pi}}
Souders-Brown terminal entrainment velocity and mist eliminator vessel sizing.
How to Use the Flash Drum Vapor Mist Wire-Mesh Demister Pad Sizing Calculator
- Input vapor mass flow in kg/hr, vapor and liquid densities in kg/m³, and empirical Souders-Brown K factor.
Step-by-Step Example Calculation
Crude Oil Separator Mist Knockout Drum
Input Values:
vaporMassFlowKgHr:18000
vaporDensityKgM3:4.5
liquidDensityKgM3:820
soudersBrownK:0.107
Worked Steps: Maximum velocity V_max = 1.44 m/s, Active pad area = 1.03 m², Minimum vessel ID = 1.15 m.
Understanding Your Result
Displays maximum allowable vapor velocity in m/s, required active demister pad area in m², and minimum vessel internal diameter.
Factors That Affect the Result
- Excessive gas velocity re-entrains sheared liquid droplets from the pad face; insufficient velocity reduces inertial impaction efficiency.
When Should You Use This Calculator?
- Flash drum sizing, compressor suction knockout pots, evaporator de-entrainment, and refinery vacuum column heads.
Assumptions & Limitations
- Applies to standard knitted wire mesh pads operated in vertical vessels with upward gas flow.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard GPSA / API 521 separator sizing formulation.