exchange in human lungs and waste removal in kidneys (dialysis) are complex mass-transfer processes [14, 16].
: Assumes the streams leaving a stage (like a tray in a tower) are in thermodynamic equilibrium. The number of "ideal stages" is calculated and then adjusted for efficiency [1, 2, 32]. Mass-transfer operations
Mass transfer is fundamentally analogous to heat and momentum transfer, often referred to as the "triple analogy". exchange in human lungs and waste removal in
dcAdzthe fraction with numerator d c sub cap A and denominator d z end-fraction ) [1.5, 5]. Mass transfer is fundamentally analogous to heat and
Engineers use two primary approaches to design mass-transfer equipment:
Mass-transfer operations are categorized by the phases involved and the method of separation [8, 32]. Phases Involved Basis of Separation Industrial Example Liquid-Vapour Differences in boiling points/volatility Petroleum refining, alcohol recovery Gas Absorption Gas-Liquid Solubility of a gas in a liquid solvent SO2cap S cap O sub 2 from flue gases Extraction Liquid-Liquid Solubility in an immiscible solvent Recovery of aromatics or edible oils Leaching Solid-Liquid Solubility of a solid solute in a solvent Extracting sugar from sugar beets Adsorption Fluid-Solid Selective adherence to a solid surface Air purification using activated carbon Drying Solid/Liquid-Gas Removal of moisture via evaporation Removing water from PVC or food products Membrane Separation Fluid-Fluid Selective permeability through a barrier Desalination (Reverse Osmosis) Design and Calculation Methods
: Described by Fick's First Law , which states that the molar flux ( JAcap J sub cap A ) is proportional to the concentration gradient (