Quantum mechanics

Mixing (physics)

Engineering

Geotechnical engineering

Nuclear physics

TRACER

Distribution (mathematics)

Computer science

Statistical physics

Fluid dynamics

Thermodynamics

Physics

Diffusion

Simulation

Mathematics

Optics

Flow (mathematics)

Residence time distribution

Mathematical analysis

Computational fluid dynamics

Residence time (fluid dynamics)

Taylor dispersion

Dispersion (optics)

Mechanics

Chemical Engineering Science

Residence Time Distribution (RTD) theory is revisited and tracer technology discussed. The background of RTD following Danckwerts ideas is presented by introducing “distribution” functions for residence time, internal age and intensity function and how to experimentally obtain them with tracer techniques (curves C and F of Danckwerts). Compartment models to describe fluid flow in real reactors are reviewed and progressive modeling of chromatographic processes discussed in some detail. The shortcomings of Standard Dispersion Model (SDM) are addressed, the Taylor-Aris model discussed and the Wave Model of Westerterp’s group introduced. The contribution of Computational Fluid Dynamics (CFD) is highlighted to calculate RTD from momentum and mass transport equations and to access spatial age distribution and degree of mixing. Finally smart RTD and future challenges are discussed.

Residence time distribution (RTD) revisited