Chemical Reaction Engineering and Reactor Design
Reactor design centers on kinetics and reactor types. Master: rate laws (zero, first, second order); Arrhenius temperature dependence (k = A·e^(−Ea/RT)); batch, CSTR and PFR design equations; space time and space velocity; conversion and selectivity; multiple reactions (series and parallel); catalysis (Langmuir-Hinshelwood, external/internal diffusion limitations); and non-isothermal reactor energy balances.
Traps: confusing space time (τ = V/v₀) with actual residence time in non-ideal reactors; misapplying the CSTR design equation (algebraic) vs PFR (differential); ignoring the effect of temperature on selectivity; and forgetting that catalyst deactivation changes kinetics over time. Questions on series reactions often test whether you know that intermediate yield is maximized at an optimum conversion.
Worked example (rule of thumb): for a first-order reaction, CSTR volume V = F_A0·X/(k·C_A0·(1−X)) = v₀·X/(k(1−X)); PFR volume V = (v₀/k)·ln(1/(1−X)). For the same conversion, PFR is always smaller than CSTR for positive-order kinetics. For series reactions A → B → C, B is maximized when the reactor is stopped at the optimum conversion.