Trying a PFR

Let's start by trying a plug-flow reactor (PFR).

The mole balances for a PFR give:

dc_A/dt = -k₁c_A + k₂c_B - k₄c_A²
dc_B/dt = k₁c_A - k₂c_B - k₃c_B

Where did these equations come from?

We have a set of ordinary differential equations (ODEs) in two variables. If we solve these equations using numerical solvers such as Polymath, Matlab or Maple V, we get the following result:

Show me how to generate this graph in PolyMath

Let's now write the mole balances for the PFR in a different form. We are going to use vector notation. You may want to go now and revised vector notation and vector mathematics in your mathematics textbook.

dcA/dt = -k1c A+k2cB-k4cA2	dcB/dt = k1cA-k2cB-k3cB
d([cA, cB])/dt = [-k1cA+k2cB-k4cA2, k1cA-k2cB-k3cB] = [rA (cA, cB), rB(cA, cB)]

Introduction > Trying a PFR > Trying a CSTR