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 = 100 L, k = 0.3 min⁻¹Q = 50 L/minCA0​ = 2 mol/LCA​ = ?

A liquid-phase first-order reaction A → B (k = 0.3 min⁻¹) runs in a 100 L continuous stirred-tank reactor (CSTR). The feed enters at 50 L/min with CA0 = 2 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 100 LQ = 50 L/mink = 0.3 min⁻¹CA0 = 2 mol/L
CA = mol/L
2.Easy
V = ?, k = 0.4 min⁻¹Q = 100 L/minX = 90%

A first-order liquid-phase reaction A → B with k = 0.4 min⁻¹ is carried out in a continuous stirred-tank reactor (CSTR) fed at 100 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 = 100 L/mink = 0.4 min⁻¹X = 90%
V = L
3.Medium
Q = 50 L/minX = 50%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 50 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 = 50 L/mink = 0.5 min⁻¹X = 50%
V = L
4.Medium
Q = 20 L/minCA0​ = 1 mol/LCA​ = ?V = 250 L, k = 0.2 min⁻¹

A liquid-phase first-order reaction A → B (k = 0.2 min⁻¹) runs in a 250 L plug-flow reactor (PFR). The feed enters at 20 L/min with CA0 = 1 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 250 LQ = 20 L/mink = 0.2 min⁻¹CA0 = 1 mol/L
CA = mol/L
5.Hard
V = 200 LQ = 40 L/minX = ?

A first-order liquid-phase reaction (k = 0.15 min⁻¹) runs in a 200 L CSTR fed at 40 L/min. The density is constant and the reactor is at steady state. Find the conversion X in percent.

V = 200 LQ = 40 L/mink = 0.15 min⁻¹
X = %
6.Hard
V = 400 LV = 400 LQ = 80 L/minX = ?

A first-order liquid-phase reaction (k = 0.3 min⁻¹) runs in two equal CSTRs in series, each of 400 L. The feed rate is 80 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 400 L (×2)Q = 80 L/mink = 0.3 min⁻¹
X = %

Answer key

  1. 1. CA = 1.25 mol/L
  2. 2. V = 2250 L
  3. 3. V = 69.31 L
  4. 4. CA = 0.08208 mol/L
  5. 5. X = 42.86 %
  6. 6. X = 84 %

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