Mass Transfer Calculator

• •Use the Mass Transfer Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations — instant feedback helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The Mass Transfer Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Fick's first law molar flux J = −D(dC/dx), convective mass transfer, Sherwood number, and Chilton-Colburn heat-mass analogy with Lewis number All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Inputs support both metric (SI) and imperial unit systems, with unit conversion handled automatically — simply select your preferred unit from the dropdown next to each field. Results are computed instantly in the browser without sending data to a server, ensuring both speed and privacy. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

Mass transfer describes the movement of chemical species through a fluid or solid medium, analogous to heat transfer. Fick's first law gives the diffusive mass flux: J = −D·dC/dx, where J is the molar flux (mol/(m²·s)), D is the diffusion coefficient (m²/s), and dC/dx is the concentration gradient. The negative sign indicates diffusion from high to low concentration. The equation is directly analogous to Fourier's law of heat conduction, with D playing the role of thermal diffusivity α = k/(ρcp). Typical diffusion coefficients: gases in air 10⁻⁵ m²/s, gases in water 10⁻⁹ m²/s, liquids in water 10⁻⁹ m²/s, solids in solids 10⁻¹⁴ m²/s. Gases diffuse about 10,000× faster in air than in water, and diffusion in solids is extremely slow. For convective mass transfer, the analogous Nusselt-like parameter is the Sherwood number Sh = h_m·L/D, where h_m is the convective mass transfer coefficient (m/s). The Reynolds analogy and Chilton-Colburn analogy relate heat and mass transfer: for similar flow, Nu/(Re·Pr^0.4) = Sh/(Re·Sc^0.4), where Sc = ν/D is the Schmidt number (analog of Prandtl number). The Schmidt number for gases in air is near 1; for liquids in water it is near 1000. The calculator handles Fick's law for 1D steady-state diffusion, convective mass transfer using Sherwood number correlations, and non-equimolar counter-diffusion for evaporation scenarios. Mass transfer concepts are fundamental to separations engineering (distillation, absorption, extraction), humidification/drying, membrane processes, and catalysis.

• •Water vapor evaporation: compute the mass transfer rate from a liquid surface to flowing air, important for cooling tower design, evaporative cooling, and drying processes.
• •Gas absorption in liquid: calculate the absorption rate of CO₂, H₂S, or other gases into a solvent in absorber columns for natural gas sweetening and air pollution control.
• •Drug delivery through skin: transdermal drug patches use diffusion through skin layers. Fick's law predicts drug flux given permeability coefficients and concentration differences.
• •Catalyst particle diffusion: inside porous catalyst pellets, reactant diffusion to active sites is often the rate-limiting step. Effective diffusivity governs catalyst effectiveness factors.
• •Distillation column design: mass transfer coefficients on each tray or in packed sections determine the efficiency of vapor-liquid separation and column height required.