1. Chapter 3 Mass Balance Recycle and Bypass

2. Recycle
Normally in chemical reaction, some of unreacted reactant also found in the product.
This unreacted reactant can be separated and recycle back to the reactor
Product
Recycle Stream
Fresh
Feed
Reactor
Separator

3. Purpose of Recycle Recovery of catalyst – catalyst is very expensive
Dilution of process stream – typically for slurry solution
Control of process variables – especially for the reaction that release heat, heat can be reduce by lowering the feed concentration
Circulation of working fluid such as in refrigerator system

4. Bypass
Fraction of the feed to a process unit is diverted around the unit and combined with the output stream from the unit
Product
Bypass Stream
Fresh
Feed
Process Unit

5. CLASS DISCUSSION EXAMPLE 4.5-1
Recycle
CLASS DISCUSSION
EXAMPLE 4.5-1

6. CLASS DISCUSSION EXAMPLE 4.5-2
Recycle vs. Unrecycle
CLASS DISCUSSION
EXAMPLE 4.5-2

7. CLASS DISCUSSION Problem 4.33
Bypass
CLASS DISCUSSION
Problem 4.33

8. ANY QUESTION?