1. Conversion and the Design Equations

2. Conversion, A
Conversion expresses the progress of a chemical reaction in terms of the limiting reactant, “A”.
If A = 0 then no “A” has reacted.
If A = 1 then all “A” has reacted.
A ≡ Moles “A” Reacted / Moles “A” Fed
= (FA0 – FA)/FA0
Rearranging
FA = FA0 (1 - A)

3. What is the Limiting Reactant?
Consider the reaction
CH3OH + 2 O2 → CO2 + 2 H2O
“A” “B”
FA = 10 mol/min
FB = 10 mol/min
Which is limiting?

4. Batch Reactor
Constant Volume

5. CSTR
Notice how this term /-rA keeps popping up?

6. PFR

7. Design Equations
Batch Reactor
CSTR
PFR

8. Example 1-1 Revisited
CSTR
PFR

9. Exothermic Reaction: A  B + C
Example
Exothermic Reaction: A  B + C
FA0 = 300 mol/min

10. CSTR
V = FA0*/-rA
V = 300*.4*.2 = 24 L

11. V = 300*[(1-.2)*.4/2
+ .2*.4] = 72 L

12. CSTR
V = FA0*/-rA
V = 300*1.1*.9 = 297 L

13. V = *[.2* *.3/2] = L