Vessel Volume & Sizing Calculator

Process & Sizing Inputs

Residence Times (Minutes)

Sizing Basis

Actions

Sizing Results

Trial Diameter (D): -
Calculated Length (L, T-T): -
Resulting L/D Ratio: -

Volume Breakdown (m³)

Cylindrical Volume (T-T): -
Single Head Volume: -
Total Vessel Volume: -

Calculated Level Setpoints (m) & Volumes (m³)

High-High (HH): -
Volume @ HH: -
High (H): -
Volume @ H: -
Normal (NLL): -
Volume @ NLL: -
Low (L): -
Volume @ L: -
Low-Low (LL): -
Volume @ LL: -

Vessel Visualization

Technical Notes

Variable Definitions

  • D: vessel internal diameter (m), r = D/2.
  • L: shell straight length between tangent lines (T-T), m.
  • Vcyl: cylindrical volume (m³) = π r² L.
  • Vhead: single head volume (m³) (depends on head type).
  • Vtot: total vessel volume (m³) = Vcyl + 2·Vhead.
  • Q: liquid flow rate (m³/h).
  • t: time band between level setpoints (min).
  • ΔV: holdup volume between two levels (m³) = Q · t / 60.
  • LL, L, NLL, H, HH: level setpoints; definition/spacing is project-specific.

Formulas / Logic

  • Head volumes (screening):
    • Hemispherical head: V = (π/12)·D³.
    • 2:1 Ellipsoidal head: V ≈ (π/24)·D³.
    • Torispherical (ASME F&D approximation): empirical V ≈ 0.0898·π·D³.
  • Vertical level → volume: volume at height h from bottom T-T is bottom-head volume + cylindrical volume up to h (clamped to L).
  • Horizontal level → volume: uses circular-segment area for the shell plus a geometric approximation for head contribution (consistent/continuous with shell).
  • Sizing mode: converts each time band into ΔV, sums required holdup LL→HH, then estimates L from V/Area with conservative LL base and optional freeboard.
  • Rating mode: computes volumes at entered levels, then surge times as t = 60·ΔV/Q.
Head-volume formulas are standard geometry relationships; torispherical is an engineering approximation (screening). Final mechanical details depend on actual head dimensions (crown/knuckle radii).

Assumptions / Notes

  • This tool is for process holdup / surge sizing and level-volume consistency. It does not replace full separator sizing (gas capacity, droplet settling, etc.).
  • Alarm/trip bands (NLL/H/HH and NLL/L/LL) should follow project control philosophy and operability requirements.
  • For horizontal vessels, liquid volume vs height is nonlinear; ensure setpoints avoid excessively steep dV/dh near very low or very high levels.
  • Always confirm minimum pump NPSH and suction submergence requirements before setting LL.
  • For final design, confirm with vendor/mechanical drawings: actual head type, dimensions, nozzle intrusions, internals, and corrosion allowance.

Standards / References

  • ASME BPVC Section VIII (vessel construction terminology and head geometries for mechanical design).
  • Perry’s Chemical Engineers’ Handbook / standard process design texts for vessel volume geometry relationships.
  • Project/Company process design practices for holdup time, alarm/trip margins, and operability.
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