Chapter
4
Mass Balances Overview
Conservation of mass. Mass isn't created or destroyed (except in
nuclear reactions).
Batch Process- Bake Bread, Make
Tires, Polymer Synthesis
Mass In = Mass Out
Continuous Process- Make Spaghetti, Polmer Extrusion,
Petroleum
Distillation
Rate of Mass In = Rate of Mass Out
Semi-Batch Process- Injection MoldingA,
Injection
Molding B
Black Box Approach
Differential (Simple) versus Integral (Can get dicey: Smoluchowski
Equation)
Some Rules to consider:
1) For Total Mass generation = consumption = 0 except for nuclear
reactions
2) For a nonreactive species generation = consumption = 0
3) For steady state, accumulation = 0 for everything.
4) For Batch you only have accumulation, generation and
consumption no in or out rates.
Steady State
Input + Generation = Output + Consumption
Batch
Initial Input + Generation = Final Output + Consumption
Chemical
Process Flow Charts