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
τ = ?k = 0.4 min⁻¹X = 85%

A first-order liquid-phase reaction with k = 0.4 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 85% conversion?

k = 0.4 min⁻¹X = 85%
τ = min
2.Easy
V = ?, k = 0.05 min⁻¹Q = 20 L/minX = 80%

A first-order liquid-phase reaction A → B with k = 0.05 min⁻¹ is carried out in a continuous stirred-tank reactor (CSTR) fed at 20 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 80% conversion of A.

Q = 20 L/mink = 0.05 min⁻¹X = 80%
V = L
3.Medium
Q = 100 L/minX = 50%V = ?, k = 0.4 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.4 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 100 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 50% conversion of A.

Q = 100 L/mink = 0.4 min⁻¹X = 50%
V = L
4.Medium
Q = 5 L/minX = 70%V = ?, k = 0.05 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.05 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 5 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 70% conversion of A.

Q = 5 L/mink = 0.05 min⁻¹X = 70%
V = L
5.Hard
V = 800 LQ = 20 L/minX = ?

A first-order liquid-phase reaction (k = 0.12 min⁻¹) runs in an 800 L CSTR fed at 20 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 800 LQ = 20 L/mink = 0.12 min⁻¹
X = %
6.Hard
Q = 25 L/minX = ?V = 250 L

A first-order liquid-phase reaction (k = 0.1 min⁻¹) runs in a 250 L plug-flow reactor (PFR) 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 = 0.1 min⁻¹
X = %

Answer key

  1. 1. τ = 14.17 min
  2. 2. V = 1600 L
  3. 3. V = 173.3 L
  4. 4. V = 120.4 L
  5. 5. X = 82.76 %
  6. 6. X = 63.21 %

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