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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
V = ?, k = 0.12 min⁻¹Q = 80 L/minX = 80%

A first-order liquid-phase reaction A → B with k = 0.12 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 80% conversion of A.

Q = 80 L/mink = 0.12 min⁻¹X = 80%
V = L
2.Easy
τ = ?k = 0.5 min⁻¹X = 85%

A first-order liquid-phase reaction with k = 0.5 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 85% conversion?

k = 0.5 min⁻¹X = 85%
τ = min
3.Medium
Q = 20 L/minCA0​ = 2 mol/LCA​ = ?V = 50 L, k = 0.15 min⁻¹

A liquid-phase first-order reaction A → B (k = 0.15 min⁻¹) runs in a 50 L plug-flow reactor (PFR). The feed enters at 20 L/min with CA0 = 2 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 50 LQ = 20 L/mink = 0.15 min⁻¹CA0 = 2 mol/L
CA = mol/L
4.Medium
Q = 40 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 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 = 0.3 min⁻¹X = 90%
V = L
5.Hard
V = 500 LQ = 10 L/minX = ?

A first-order liquid-phase reaction (k = 0.2 min⁻¹) runs in a 500 L CSTR fed at 10 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 500 LQ = 10 L/mink = 0.2 min⁻¹
X = %
6.Hard
V = 1000 LV = 1000 LQ = 100 L/minX = ?

A first-order liquid-phase reaction (k = 0.12 min⁻¹) runs in two equal CSTRs in series, each of 1000 L. The feed rate is 100 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 1000 L (×2)Q = 100 L/mink = 0.12 min⁻¹
X = %

Answer key

  1. 1. V = 2667 L
  2. 2. τ = 11.33 min
  3. 3. CA = 1.375 mol/L
  4. 4. V = 307 L
  5. 5. X = 90.91 %
  6. 6. X = 79.34 %

Full step-by-step solutions: practise this topic on examproblems.com.