Chapter 3
Mass Balance
Balance on Multiple
Unit Processes
Balances on Multiple Unit Processes
 In real chemical industries, more than one unit
processes exist such as a separation unit after reactor
and so on.
 Need to know term called SYSTEM in order to solve
material problem
 SYSTEM:
 Any portion of process that can be enclosed within
a hypothetical box (or boundary)
 It can be the entire process, an interconnected of
process unit, a single unit, a point which two or
more stream come together into one stream or etc.
 The inputs and outputs to a system are the process
streams that are intersect to the system boundary
System of Multiple Unit Processes
C
A
D
B
E
Balances on Multiple Unit Processes
 Solving material balances in multiple unit process
is basically the same as single unit processes
 In multiple unit, must isolate and write balance
on several subsystems to obtain enough equation
to determine all unknowns stream variables
 Always perform degree-of-freedom analysis
before solving a material balance of system.
CLASS DISCUSSION
ANY
QUESTION?