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
τ = ?k = 0.12 min⁻¹X = 75%

A first-order liquid-phase reaction with k = 0.12 min⁻¹ runs in a CSTR at steady state. What space time τ is needed to reach 75% conversion?

k = 0.12 min⁻¹X = 75%
τ = min
2.Easy
V = ?, k = 0.15 min⁻¹Q = 20 L/minX = 95%

A first-order liquid-phase reaction A → B with k = 0.15 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 95% conversion of A.

Q = 20 L/mink = 0.15 min⁻¹X = 95%
V = L
3.Medium
Q = 25 L/minX = 80%V = ?, k = 0.25 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.25 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 80% conversion of A.

Q = 25 L/mink = 0.25 min⁻¹X = 80%
V = L
4.Medium
Q = 20 L/minX = 85%V = ?, k = 0.08 min⁻¹

A first-order liquid-phase reaction A → B with k = 0.08 min⁻¹ is carried out in a plug-flow reactor (PFR) fed at 20 L/min. The density is constant and the reactor is at steady state. Find the reactor volume V in litres for 85% conversion of A.

Q = 20 L/mink = 0.08 min⁻¹X = 85%
V = L
5.Hard
V = 500 LV = 500 LQ = 40 L/minX = ?

A first-order liquid-phase reaction (k = 0.3 min⁻¹) runs in two equal CSTRs in series, each of 500 L. The feed rate is 40 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 500 L (×2)Q = 40 L/mink = 0.3 min⁻¹
X = %
6.Hard
V = 2000 LV = 2000 LQ = 40 L/minX = ?

A first-order liquid-phase reaction (k = 0.08 min⁻¹) runs in two equal CSTRs in series, each of 2000 L. The feed rate is 40 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 2000 L (×2)Q = 40 L/mink = 0.08 min⁻¹
X = %

Answer key

  1. 1. τ = 25 min
  2. 2. V = 2533 L
  3. 3. V = 160.9 L
  4. 4. V = 474.3 L
  5. 5. X = 95.57 %
  6. 6. X = 96 %

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