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 = 0.1 min⁻¹X = 95%

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 95% conversion?

k = 0.1 min⁻¹X = 95%
τ = min
2.Easy
τ = ?k = 0.05 min⁻¹X = 50%

A first-order liquid-phase reaction with k = 0.05 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 50% conversion?

k = 0.05 min⁻¹X = 50%
τ = min
3.Medium
Q = 40 L/minX = 75%V = ?, k = 0.5 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.5 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 40 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 75% conversion of A.

Q = 40 L/mink = 0.5 min⁻¹X = 75%
V = L
4.Medium
Q = 25 L/minX = 50%V = ?, k = 0.15 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.15 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 50% conversion of A.

Q = 25 L/mink = 0.15 min⁻¹X = 50%
V = L
5.Hard
Q = 80 L/minX = ?V = 250 L

A first-order liquid-phase reaction (k = 0.5 min⁻¹) runs in a 250 L plug-flow reactor (PFR) fed at 80 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 250 LQ = 80 L/mink = 0.5 min⁻¹
X = %
6.Hard
V = 2000 LQ = 25 L/minX = ?

A first-order liquid-phase reaction (k = 0.08 min⁻¹) runs in a 2000 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 = 2000 LQ = 25 L/mink = 0.08 min⁻¹
X = %

Answer key

  1. 1. τ = 190 min
  2. 2. τ = 20 min
  3. 3. V = 110.9 L
  4. 4. V = 115.5 L
  5. 5. X = 79.04 %
  6. 6. X = 86.49 %

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