Reaction & separation

Chemical Reaction Engineering

5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.

Topics

Reaction Kinetics
Reaction kinetics quantifies how fast a reaction proceeds through a rate law −r_A = k·C_A^a…; the rate constant follows Arrhenius temperature dependence, and orders are determined experimentally, not from stoichiometry unless the step is elementary.
$Half-life t_\frac{1}{2} = ln \frac{2}{k} for a first-order reaction$
Isothermal Reactor Design
Isothermal reactor sizing integrates the mole balance: a PFR needs the integral of 1/(−r_A) over conversion, while a CSTR uses the single outlet-rate value; for positive-order kinetics the PFR is always the smaller reactor.
Non Isothermal Reactor Design
Non-isothermal design couples the mole balance to an energy balance, because temperature changes the rate through Arrhenius; adiabatic reactors follow a linear temperature-conversion path, and exothermic cooled CSTRs can exhibit multiple steady states.
RTD and Non Ideal Reactors
The residence-time distribution E(t) describes how long fluid elements stay in a real reactor; its mean gives the space time and its variance diagnoses non-ideality, feeding models like tanks-in-series or dispersion to predict conversion.
$Ideal PFR: E(t) = \delta(t - \tau); ideal CSTR: E(t) = (\frac{1}{\tau}) e^(-\frac{t}{\tau})$
Catalysis Basics
Heterogeneous catalysis proceeds through adsorption, surface reaction and desorption; Langmuir-Hinshelwood kinetics captures site competition, while the Thiele modulus and effectiveness factor quantify how internal pore diffusion can throttle the intrinsic rate.
$Effectiveness factor \eta = actual \frac{rate}{rate} without diffusion limit$