Process Design

When designing a pressure vessel, storage tank, or reactor, accurately calculating the internal volume is one of the most fundamental steps in process engineering. The internal volume dictates the residence time of chemical reactions, the liquid inventory for surge capacity, and the safe handling limits during relief scenarios. While the cylindrical shell’s volume is a simple geometry, the vessel ends—known as Heads—come in various complex shapes. The geometry of a head significantly affects not only the volume but also the stress distribution, required wall thickness, and manufacturing cost. ...

Sizing a control valve correctly is one of the most critical steps in process engineering. If a valve is undersized, it won’t be able to pass the required flow. If it is oversized, it will operate too close to its seat, leading to poor control, instability, and premature wear. This interactive tool calculates the required Flow Coefficient ($C_v$) for both liquid and compressible gas/vapor services based on the international standard IEC 60534-2-1 (equivalent to ISA S75.01). ...

Sizing a Restriction Orifice (RO) or evaluating flow across a given orifice plate is a daily task in process engineering. Whether you are checking pump minimum flow lines (liquids) or making a preliminary estimate for gas restriction cases, understanding flow limits—especially choked flow—is critical. This browser-based estimator provides preliminary mass-flow and upstream actual volumetric-flow estimates across an orifice for compressible gases and incompressible liquids. 🎛️ Restriction Orifice Flow Estimator • Gas Mode: Calculates upstream density from P1, T1, MW, and Z. Uses subcritical/choked split. • Liquid Mode: Uses incompressible orifice equation (no cavitation/flashing check). Fluid Data Fluid Phase Gas (Compressible) Liquid (Incompressible) Upstream Pressure P1 (bar abs) Downstream Pressure P2 (bar abs) Temperature T1 (°C) Molecular Weight MW (kg/kmol) Compressibility Factor Z Ratio of Specific Heats, k = Cp/Cv Density at P1 (kg/m³) Dynamic Viscosity (cP, ref. only) Instrument Data Pipe Inner Diameter D (mm) Orifice Bore Diameter d (mm) Discharge Coefficient (Cd) Calculate Flow Calculation Results 🚨 Choked flow detected. Gas flow is limited by sonic condition at the vena contracta. ⚠️ Engineering Disclaimer * Cd is strictly user-specified and is NOT dynamically correlated to the Reynolds number. * Gas mode applies the incompressible velocity-of-approach factor (E) to the isentropic equation as a pragmatic approximation. * Reported volumetric flow is based strictly on upstream actual density and should be interpreted as upstream actual conditions (not standard/normal or downstream). * Use for preliminary engineering estimation only. Not a full ISO 5167 or rigorous dynamic sizing package. 🚨 Engineering Limitations & Disclaimer Before using the estimates provided by this tool, please note the following critical boundaries: ...

Estimating the Wetted Surface Area is one of the most critical steps when sizing Pressure Safety Valves (PSVs) and emergency venting for fire scenarios. This professional-grade calculator goes beyond simple geometry by fully incorporating the nuances, conservative conventions, and standard-mandated rules of API STD 521 (Process Vessels) and API STD 2000 / KOSHA D-14 (Storage Tanks). “Built for process engineers: Inputs align directly with your P&ID and Datasheets using Tangent Line (TL) elevations.” ...