Process Bench — Chemical Engineering Calculators

Free browser-based calculators for chemical and process engineering: vapor pressure, pipe pressure drop, pump and relief-valve sizing, heat transfer, and more.

Fluid Mechanics

• Pipe Pressure Drop Calculator — Frictional ΔP and head loss for single-phase flow in a circular pipe (Darcy–Weisbach, Swamee–Jain friction factor).
• Fittings Pressure Drop (K-factors) Calculator — Minor losses through elbows, tees, and valves by the ΣK excess-head method — the companion to straight-pipe friction.
• Pipe Velocity & Reynolds Calculator — Line velocity, Reynolds number, and flow regime from flow rate and pipe inside diameter.
• Friction Factor (Moody) Calculator — Darcy (and Fanning) friction factor from Reynolds number and relative roughness — Colebrook–White solved exactly, with the Swamee–Jain explicit fit for comparison.
• Pipe Line Sizing (velocity) Calculator — Required pipe bore for a target line velocity, with the resulting velocity and typical service velocity guidance.
• Orifice Plate Flow Calculator — Flow rate through a sharp-edged orifice plate from measured differential pressure (ISO 5167 form, incompressible).
• Tank Drain Time Calculator — Time to gravity-drain a vertical cylindrical tank through a bottom orifice or nozzle (Torricelli).
• Tank Volume Calculator — Total capacity and liquid volume at a given level for a cylindrical tank with flat, 2:1 ellipsoidal, or hemispherical heads — vertical or horizontal.
• Pump Sizing (API 610) Calculator — Hydraulic, shaft, and motor power for a centrifugal pump from flow, head, and efficiencies, with an API 610 motor-margin recommendation.
• NPSH Available Calculator — Net positive suction head available at a pump, with optional margin check against NPSH required.
• Pump Affinity Laws Calculator — Scale pump flow, head, and power to a new speed or impeller diameter using the affinity laws.
• Control Valve Cv (Liquid) Calculator — Flow coefficient (Cv and Kv) for a liquid-service control valve, with a choked-flow / cavitation check.

Heat Transfer

• Heat Exchanger LMTD Calculator — Log-mean temperature difference for a two-stream exchanger, plus duty Q if you supply U and area.
• Heat Exchanger Duty & Area Calculator — Sensible heat duty from flow, specific heat, and temperature change — plus the required exchanger area from U and the LMTD.
• Insulated Pipe Heat Loss Calculator — Heat loss per metre and total from an insulated pipe, with the outer-surface temperature (personnel-protection check).

Process Safety

• Relief Valve Sizing (API 520) Calculator — Required PSV orifice area for vapor (critical flow) or liquid service per API 520, with the selected API 526 standard orifice.

Thermodynamics

• Vapor Pressure (Antoine) Calculator — Saturation pressure of a pure component from Antoine coefficients. Pick a preset or enter your own A, B, C.
• Ideal Gas Law Calculator — Moles, mass, and density of an ideal gas from P, V, and T.
• Gas Compressor Power Calculator — Single-stage adiabatic compression power, head, and discharge temperature for an ideal gas.
• Steam Tables (IAPWS-IF97) Calculator — Saturated and single-phase water/steam properties — saturation pressure/temperature, enthalpy, entropy, and specific volume — from the IAPWS-IF97 standard.

Reference tables

• Schedule 40 & 80 steel pipe dimensions — Outside diameter, wall thickness, and inside diameter for Schedule 40 and Schedule 80 carbon-steel pipe, by nominal pipe size (NPS), in millimetres.
• Absolute pipe roughness (ε) for common materials — Typical absolute roughness values (ε, in mm) for commercial pipe materials — used in the Colebrook equation and the Moody chart for friction-factor and pressure-drop calculations.
• Recommended fluid velocities for pipe sizing — Typical recommended velocity ranges for liquid, gas, and steam lines — rule-of-thumb bands used to size pipe before detailed pressure-drop analysis.

Databases

• Compound property database — molar mass, boiling point, density, and Antoine vapor pressure for common compounds
• Engineering unit converter — pressure, flow, temperature, power, and more, with per-unit conversion pages

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