Reactor sizing (CSTR & PFR) worksheet with answers

Free printable Reactor sizing (CSTR & PFR) worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
V = 2000 L, k = 0.4 min⁻¹Q = 80 L/minCA0​ = 0.5 mol/LCA​ = ?

A liquid-phase first-order reaction A → B (k = 0.4 min⁻¹) runs in a 2000 L continuous stirred-tank reactor (CSTR). The feed enters at 80 L/min with CA0 = 0.5 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 2000 LQ = 80 L/mink = 0.4 min⁻¹CA0 = 0.5 mol/L
CA = mol/L
2.Easy
τ = ?k = 0.1 min⁻¹X = 70%

A first-order liquid-phase reaction with k = 0.1 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 70% conversion?

k = 0.1 min⁻¹X = 70%
τ = min
3.Medium
Q = 25 L/minX = 90%V = ?, k = 0.1 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.1 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 25 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 90% conversion of A.

Q = 25 L/mink = 0.1 min⁻¹X = 90%
V = L
4.Medium
Q = 25 L/minX = 90%V = ?, k = 0.3 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.3 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 25 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 90% conversion of A.

Q = 25 L/mink = 0.3 min⁻¹X = 90%
V = L
5.Hard
Q = 10 L/minX = ?V = 200 L

A first-order liquid-phase reaction (k = 0.08 min⁻¹) runs in a 200 L plug-flow reactor (PFR) fed at 10 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 200 LQ = 10 L/mink = 0.08 min⁻¹
X = %
6.Hard
V = 250 LQ = 25 L/minX = ?

A first-order liquid-phase reaction (k = 0.5 min⁻¹) runs in a 250 L CSTR fed at 25 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 250 LQ = 25 L/mink = 0.5 min⁻¹
X = %

Answer key

  1. 1. CA = 0.04545 mol/L
  2. 2. τ = 23.33 min
  3. 3. V = 575.6 L
  4. 4. V = 191.9 L
  5. 5. X = 79.81 %
  6. 6. X = 83.33 %

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