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 = 1000 L, k = 0.3 min⁻¹Q = 20 L/minCA0​ = 2.5 mol/LCA​ = ?

A liquid-phase first-order reaction A → B (k = 0.3 min⁻¹) runs in a 1000 L continuous stirred-tank reactor (CSTR). The feed enters at 20 L/min with CA0 = 2.5 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 1000 LQ = 20 L/mink = 0.3 min⁻¹CA0 = 2.5 mol/L
CA = mol/L
2.Easy
τ = ?k = 0.5 min⁻¹X = 80%

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 80% conversion?

k = 0.5 min⁻¹X = 80%
τ = min
3.Medium
Q = 80 L/minCA0​ = 1 mol/LCA​ = ?V = 500 L, k = 0.08 min⁻¹

A liquid-phase first-order reaction A → B (k = 0.08 min⁻¹) runs in a 500 L plug-flow reactor (PFR). The feed enters at 80 L/min with CA0 = 1 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 500 LQ = 80 L/mink = 0.08 min⁻¹CA0 = 1 mol/L
CA = mol/L
4.Medium
Q = 10 L/minCA0​ = 0.5 mol/LCA​ = ?V = 250 L, k = 0.1 min⁻¹

A liquid-phase first-order reaction A → B (k = 0.1 min⁻¹) runs in a 250 L plug-flow reactor (PFR). The feed enters at 10 L/min with CA0 = 0.5 mol/L. The density is constant and the reactor is at steady state. Find the outlet concentration CA.

V = 250 LQ = 10 L/mink = 0.1 min⁻¹CA0 = 0.5 mol/L
CA = mol/L
5.Hard
V = 100 LV = 100 LQ = 20 L/minX = ?

A first-order liquid-phase reaction (k = 0.05 min⁻¹) runs in two equal CSTRs in series, each of 100 L. The feed rate is 20 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 100 L (×2)Q = 20 L/mink = 0.05 min⁻¹
X = %
6.Hard
V = 100 LV = 100 LQ = 50 L/minX = ?

A first-order liquid-phase reaction (k = 0.25 min⁻¹) runs in two equal CSTRs in series, each of 100 L. The feed rate is 50 L/min, the density is constant and the reactors are at steady state. Find the overall conversion X in percent.

V = 100 L (×2)Q = 50 L/mink = 0.25 min⁻¹
X = %

Answer key

  1. 1. CA = 0.1563 mol/L
  2. 2. τ = 8 min
  3. 3. CA = 0.6065 mol/L
  4. 4. CA = 0.04104 mol/L
  5. 5. X = 36 %
  6. 6. X = 55.56 %

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