1. Reactor Design for Selective Product Distribution
S,S&L Chapt. 7

2. Overview Parallel Reactions Series Reactions Independent Reactions
A+BR (desired)
AS
Series Reactions
ABC(desired)D
Independent Reactions
AB (desired)
CD+E
Series Parallel Reactions
A+BC+D
A+CE(desired)
Mixing, Temperature and Pressure Effects

3. Examples Ethylene Oxide Synthesis CH2=CH2 + O22CO2 + 2H2O
CH2=CH2 + O2CH2-CH2(desired) O

4. Examples
Diethanolamine Synthesis

5. Examples
Butadiene Synthesis, C4H6, from Ethanol

6. Rate Selectivity Parallel Reactions Rate Selectivity
A+BR (desired)
A+BS
Rate Selectivity
(αD- αU) >1 make CA as large as possible
(βD –βU)>1 make CB as large as possible
(kD/kU)= (koD/koU)exp[-(EA-D-EA-U)/(RT)]
EA-D > EA-U T
EA-D < EA-U T

7. Reactor Design to Maximize Desired Product

8. Maximize Desired Product
Series Reactions
AB(desired)CD
Plug Flow Reactor
Optimum Time in Reactor

9. Fractional Yield
(k2/k1)=f(T)

10. Real Reaction Systems More complicated than either
Series Reactions
Parallel Reactions
Effects of equilibrium must be considered
Confounding heat effects
All have Reactor Design Implications

11. Engineering Tricks Reactor types
Multiple Reactors
Mixtures of Reactors
Bypass
Recycle after Separation
Split Feed Points/ Multiple Feed Points
Diluents
Temperature Management