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 = 0.15 min⁻¹X = 75%

A first-order liquid-phase reaction with k = 0.15 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 75% conversion?

k = 0.15 min⁻¹X = 75%
τ = min
2.Easy
V = ?, k = 0.3 min⁻¹Q = 80 L/minX = 90%

A first-order liquid-phase reaction A → B with k = 0.3 min⁻¹ is carried out in a continuous stirred-tank reactor (CSTR) fed at 80 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 = 80 L/mink = 0.3 min⁻¹X = 90%
V = L
3.Medium
Q = 5 L/minX = 90%V = ?, k = 0.12 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.12 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 90% conversion of A.

Q = 5 L/mink = 0.12 min⁻¹X = 90%
V = L
4.Medium
Q = 40 L/minX = 90%V = ?, k = 0.2 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.2 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 90% conversion of A.

Q = 40 L/mink = 0.2 min⁻¹X = 90%
V = L
5.Hard
Q = 50 L/minX = ?V = 50 L

A first-order liquid-phase reaction (k = 0.4 min⁻¹) runs in a 50 L plug-flow reactor (PFR) fed at 50 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 50 LQ = 50 L/mink = 0.4 min⁻¹
X = %
6.Hard
V = 2000 LQ = 20 L/minX = ?

A first-order liquid-phase reaction (k = 0.3 min⁻¹) runs in a 2000 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 = 2000 LQ = 20 L/mink = 0.3 min⁻¹
X = %

Answer key

  1. 1. τ = 20 min
  2. 2. V = 2400 L
  3. 3. V = 95.94 L
  4. 4. V = 460.5 L
  5. 5. X = 32.97 %
  6. 6. X = 96.77 %

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