Recycle Mass Balances: Summary

The answers to the ConcepTests are given below and will open in a separate window. 
Key points from this module:
  • A recycle stream starts from a downstream unit in the process and moves to an upstream one.
  • A recycle stream is ignored in an overall balance.
  • Separating product(s) at a reactor exit and recycling the reactant(s) increases the overall conversion for the process.
  • A system with recycle is run at steady state.
  • A degree of freedom analysis is useful for determining where to carry out mass balances for a process with recycle.
  • A recycle stream can be used to increase overall conversion in a reactor system.
From studying this module, you should now be able to:
  • Explain how a recycle stream affects a process.
  • Carry out mass balances on a non-reactive system with recycle.
  • Carry out mass balances on a reactor system with recycle.

See also: Purge Stream in a System with Recycle

Prepared by Michelle Medlin and John L. Falconer, Department of Chemical and Biological Engineering, University of Colorado Boulder