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 = 400 L, k = 0.15 min⁻¹Q = 100 L/minCA0​ = 2 mol/LCA​ = ?

A liquid-phase first-order reaction A → B (k = 0.15 min⁻¹) runs in a 400 L continuous stirred-tank reactor (CSTR). The feed enters at 100 L/min with CA0 = 2 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 400 LQ = 100 L/mink = 0.15 min⁻¹CA0 = 2 mol/L
CA = mol/L
2.Easy
V = ?, k = 0.15 min⁻¹Q = 80 L/minX = 70%

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 80 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 = 80 L/mink = 0.15 min⁻¹X = 70%
V = L
3.Medium
Q = 100 L/minX = 75%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 100 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 = 100 L/mink = 0.12 min⁻¹X = 75%
V = L
4.Medium
QX = 90%same Q, k and X as the CSTR

A first-order liquid-phase reaction must reach 90% conversion. How many times larger must a CSTR be than a PFR for the same feed rate, rate constant and conversion? Find the ratio VCSTR/VPFR.

X = 90%first order, same k and Q
VCSTR/VPFR =
5.Hard
V = 150 LQ = 25 L/minX = ?

A first-order liquid-phase reaction (k = 0.25 min⁻¹) runs in a 150 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 = 150 LQ = 25 L/mink = 0.25 min⁻¹
X = %
6.Hard
V = 50 LQ = 50 L/minX = ?

A first-order liquid-phase reaction (k = 0.25 min⁻¹) runs in a 50 L CSTR 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 = 0.25 min⁻¹
X = %

Answer key

  1. 1. CA = 1.25 mol/L
  2. 2. V = 1244 L
  3. 3. V = 1155 L
  4. 4. VCSTR/VPFR = 3.909
  5. 5. X = 60 %
  6. 6. X = 20 %

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