Engineering Tool
Demister Sizing Calculator
Souders-Brown first-pass sizing: Vmax = K √((ρL − ρV) / ρV). Pick a documented K factor for your service, enter actual gas flow and densities.
Operating Conditions
Enter a K value from your project design basis or a verified engineering source. This tool does not select K for the service.
Sizing Result
Enter your documented project K value to size this duty. This tool deliberately supplies no default, because the allowable K depends on pressure, foaming, liquid load, mesh construction and required margin.
The equivalent diameter is a flow-area check, not a fabrication diameter or vessel ID. Send us these numbers plus temperature, pressure, medium, vessel ID, support details and manway size for a preliminary engineering review.
Engineering Disclaimer — Demister Sizing Calculator (Souders-Brown) (v1.0, updated 2026-08)
This tool provides preliminary estimates only, based on generalized correlations and typical service assumptions. Actual performance depends on operating conditions, fouling, turndown, mist load, and vessel internals. Results must be verified by a qualified process engineer before purchase or fabrication. Meshium accepts no liability for decisions made solely on this output.
Engineering references: GPSA Engineering Data Book and Perry’s Chemical Engineers’ Handbook for preliminary separator-sizing practice. They are engineering references, not normative standards; this tool does not reproduce or prescribe a K value from either publication.
Need project-specific review? Send us your operating conditions — for complete inquiries received on business days (UTC+8), we target a 24-hour preliminary engineering reply.
How this calculation works
The Souders-Brown equation gives an empirical maximum (capacity) superficial vapor velocity above which liquid re-entrainment risk rises — it is an experience-based allowable velocity, not a rigorously calculated flooding point. The K factor bundles droplet behavior, separator construction and service experience. It must be selected from a verified project or engineering basis for the actual duty; this tool does not prescribe one.
The separate design-fraction input applies an explicit margin below the calculated Vmax. Its 75% starting value and the tool's 85% upper guardrail are preliminary software conventions, not standard requirements. Check the project basis before adding a margin because a documented K value may already include derating. The required flow area then follows from actual volumetric flow; the equivalent round diameter is only a flow-area expression, not the tower ID or fabrication OD. The tool does not model liquid load, inlet distribution, horizontal-flow orientation, foaming, fouling or drainage.
Required Basis
Bring a documented K value
What the calculator needs
- - Actual gas flow at operating temperature and pressure
- - Vapor and liquid densities at the stated conditions
- - A project K value with its source and applicable service
- - A separately chosen design fraction below calculated Vmax
What still needs review
The result is only a preliminary required flow area and equivalent round flow diameter. Before quotation, check vessel ID, manway size, liquid load, inlet distribution, drainage, support details, material and the actual operating envelope.
Send These ConditionsSizing FAQ
Where should the K factor come from?
Use a K value documented for the actual service in the project design basis or a verified engineering source. Pressure, liquid load, foaming, fouling, pad construction and vessel arrangement can all change the applicable value; this calculator therefore supplies no default K.
Why does the calculator use actual gas flow?
Demister face velocity is based on actual volumetric flow at operating temperature and pressure. Normal flow must be converted to actual flow before sizing.
Can this result be used directly for fabrication?
No. It gives required flow area and an equivalent round flow diameter, not a fabrication diameter or vessel ID. Final fabrication still needs vessel ID, manway size, support ring, liquid load, material, segmentation and inspection requirements.