Isothermal Semibatch Reactors: Interactive Simulation
This simulation was prepared using MathematicaDownload the free CDF player and then download the simulation CDF file (link given below or click on figure to download). Try to predict the behavior when a parameter changes before using a slider to change that parameter. For this simulation, a screencast is provided to explain how to use it.

Simulation: Selectivity in a Semibatch Reactor

The parallel reactions A + B → D  and A + B → U are carried out in an isothermal semibatch reactor. Both reactions are first-order in A. The desired reaction to form the product D is second-order in B, whereas the undesired reaction to form product U is first-order in B. Both reactions are irreversible. This Demonstration compares two scenarios: (1) pure A is fed to a reactor that initially contains only B, and (2) pure B is fed to a reactor that initially contains only A. You can vary the activation energies of each reaction and the isothermal reactor temperature to determine how selectivity and moles of products and reactants change with time. The amounts of both products increase with temperature because the reactions are irreversible.



Try to answer these questions before determining the answer with the simulation:

  1. Two parallel reactions (A + B → products) take place in an isothermal semibatch reactor. Both reactions are first-order in A. The desired reaction is second-order in B, whereas the undesired reaction is first-order in B. Which component should initially be in the reactor and which component should be added over time.
  2. Two parallel reactions (A + B → products) take place in an isothermal semibatch reactor. Both reactions are first-order in A. The desired reaction is second-order in B, whereas the undesired reaction is first-order in B. Does selectivity increase or decrease as a function of time if the reactor starts with B and A is added?