Catalysis:Basic Layout

From Wiketomica
Introduction
Background
Basic Layout
Example
Problems
Run Simulation
References
Credits
Assessment
Etomica Modules

The heterogeneous catalysis module simulates a batch catalytic reactor, with an initial mixture of gaseous CO and O2 and a model catalyst surface. The module has several features and components relevant to its use and interpretation. These include:

  • Adiabatic or isothermal modes of operation
  • Choice of initial numbers of CO and O2 molecules
  • Choice of two catalysts (A and B)
  • “Configuration” window – allows the user to see the gas phase as well as the catalyst surface simultaneously, and follow the real time dynamics of the reaction system
  • “Metrics” window – records instantaneous time, volume (constant, in this case), and species (CO, O2, and CO2) gas phase concentrations
  • “Temperature” window – graphically records the time-dependent temperature profile in the batch reactor
  • “Density” window – graphically records the various species gas phase densities/concentrations versus time
  • “Simulation Delay” – to slow down the visualization on the screen, to assist with visualizing molecular motion/mechanism
  • “Start”/“Pause”/“Continue” buttons – to start, pause, and restart the simulation as needed
  • “Reinitialize” – to return the collection of molecules to their original configuration before initiating reaction
  • “Reset Averages” – resets the values recorded on the “Metrics”, “Temperature”, and “Density” windows

The module makes use of a color coding scheme to identify different species in the overall reaction system. The key to this scheme is listed in the table below:

Species Color
Carbon atoms in CO, gas-phase Blue
Oxygen atoms in CO, O2, and CO2, gas-phase Red
Carbon atoms in adsorbed CO on surface Cyan
Oxygen atoms adsorbed onto surface Light Grey
Carbon atoms in CO2, gas-phase Yellow

After setting up a given initial reactor configuration, press the start button to begin. Gas-phase molecules move throughout the vapor phase and interact with the catalyst surface. The module now allows for the simultaneous evolution of both spatial and temporal changes in the catalytic system. Spatially, one can view the dynamics and interactions of the reacting species. Temporally, the dynamics of the surface chemistry evolve, thereby revealing the overall, apparent reaction kinetics. The system is now ready for characterization using techniques learned from chemical reaction engineering courses.