Chemical Engineering Glossary

A mass transfer operation where a gas-phase component is dissolved into a liquid solvent.

The minimum energy required for reactant molecules to undergo a chemical reaction.

A process or system with no heat transfer to or from the surroundings.

A reactor where all reactants are charged at the start, the reaction proceeds, and products are removed at the end with no flow during the reaction.

An equation relating pressure, velocity, and elevation for steady, incompressible, frictionless fluid flow.

A substance that increases the rate of a chemical reaction by lowering activation energy without being consumed.

The study of reaction rates and the factors (temperature, concentration, catalysts) that influence how fast reactions occur.

Continuously Stirred Tank Reactor; an ideal reactor model assuming perfect mixing throughout the vessel.

A separation process that exploits differences in component volatilities (boiling points) to separate liquid mixtures.

A reaction or process that absorbs heat from its surroundings, resulting in a positive enthalpy change.

A thermodynamic property representing the total heat content of a system at constant pressure ($H = U + PV$).

A thermodynamic measure of disorder or randomness in a system; the Second Law states it always increases in an isolated system.

A reaction or process that releases heat to its surroundings, resulting in a negative enthalpy change.

A law stating that the rate of diffusion is proportional to the concentration gradient.

A bed of solid particles suspended by an upward flow of fluid, providing excellent mixing and heat transfer.

A law stating that the rate of heat conduction is proportional to the negative temperature gradient.

A thermodynamic potential ($G = H - TS$) that determines the spontaneity and equilibrium of reactions at constant $T$ and $P$.

Hazard and Operability study; a systematic method for identifying process hazards using guide words applied to process parameters.

Equipment designed to transfer heat between two fluid streams without mixing them.

When a system at equilibrium is disturbed, it shifts to partially counteract the disturbance.

Log Mean Temperature Difference; the driving force for heat transfer in a heat exchanger, accounting for changing temperature differences.

The movement of chemical species from one location to another, driven by concentration gradients.

Plug Flow Reactor; an ideal reactor model where fluid flows as discrete plugs with no axial mixing.

For ideal solutions, the partial pressure of a component equals its mole fraction in the liquid times its pure-component vapor pressure ($P_i = x_i P_i^{\text{sat}}$).

A basic step in a chemical process involving a physical or chemical change, such as distillation, filtration, or drying.