Example 2

  • Metering is the act of measuring materials as they are transferred from one unit to another.
  • There are two main types employed in batch processing: volumetric (measuring volume of flow) and gravimetric (measuring weight). For the purposes of process modeling, it is not important how materials are metered but rather where they are metered.
  • Imagine that units A and B in our example contain bulk ingredients and that units C and D are reactors where some processing activity takes place.
  • Further assume that C and D are on load cells (we are measuring weight) and we can therefore calculate the amount of material added to C or D by observing the gain-in-weight of the unit during the transfer.
  • It is undesirable to have both A and B transferring material to C (or D) at the same time since our destination unit is only measuring it's gain-in-weight.
  • We cannot tell how much material is coming from A and how much is coming from B if they occur simultaneously.
  • On the other hand, there is no reason to prevent unit A from transferring to units C and D simultaneously since each C and D can each measure the amount of material they receive.
  • Therefore we wish to prevent AC+BC and AD+BD as well as the obvious AD+BC.
  • Modeling Seg 3 and Seg 4 as well as Seg 5 gives the desired result.

Last modified: Saturday, 2 May 2020, 10:26 AM