1. Chemical Reaction Engineering Reactor Design
Pam Kubinski, Bethany Schmid,
Joe Haupt

2. Overview Project Specifications Background Reactor Designs Results
Optimization
Comparison

3. Project Specifications
Formation of Maleic anhydride from n-butane
Fixed bed reactor design
40,000 Mtons/yr
Reactor Designs
Single reaction kinetics
Isothermal, isobaric
Isothermal including pressure drop
Kinetics from literature
Multiple Reactions-isothermal
Multiple Reactions-including energy balance

4. Background of Maleic Anhydride
Produced from oxidation of:
N-butane
Benzene
N-butene
Used in manufacture of
Resins
Lubricant Additives
Surface Coatings
Plasticizers
Maleic Anhydride
We are way better than benzene and butene 63% resin
Butane
0.50 $/L
Maleic Anhydride
1.70 $/kg

5. Fixed Bed Technology

6. Isothermal-Isobaric Reactor Design
Reaction and Kinetics
C4H O2 → C4H2O3 + 4H20
Added Constraints
80% Conversion
No side reactions
Bulk Density 900 kg/m3
Inlet Conditions
220 kPa
1.7 mol % Butane
400 C

7. Results As inlet temperature increases conversion of butane increases
Conversion Profiles for Various Isotherms
63000 kg catalyst
As inlet temperature increases conversion of butane increases

8. Pressure Drop Reactor Design
Additional Constraints
Used Ergun Equation
Evaluated
5 mm particles
7 mm Particles
ε = 0.44

9. Conversion Profiles Solid lines- isobaric
Increased catalyst to account for pressure drop kg to kg (73 m3)
Solid lines- isobaric
Dotted lines- including pressure drop

10. Pressure Drop Results Held reactor volume constant
73.5 m ,150 kg
Held reactor volume constant
Varied tube diameter

11. Pressure Drop Results Held reactor volume constant
Varied reactor length

12. Multiple Reaction Kinetics1 2 3
C4H O2 → C4H2O3 + 4H2O
C4H2O3 + O2 → 4CO + CO2 + H2O
C4H O2 → 2CO + 2CO2 + 5H2O

13. Molar Flow Profile
Flows excluding inert

14. Isothermal Results

15. Including Energy Balance
Additional Specifications
Constant coolant temperature C
Constant heat capacities- low Δ T
Overall Heat Transfer Constant J/(m2-s-K)
Multi-tubular Reactor

16. Coolant Temperature Results
Hot Spot! Ta
Selectivity
693
0.293
673
0.326
653
0.442
Talk about hot spot

17. Inlet Temperature Results

18. Optimal Reactor Design
Optimization Results
Optimal Reactor Design
Inlet temperature
703 K
Reactor Volume
253.5 m3
Number of Tubes
76,535
Conversion
0.860
Pressure Drop
9.97%
Selectivity
0.319
Hot spot temperature
733.3 K
Within pressure
Increased inlet temperature
Minimized reactor volume

19. Comparison Variable Final Design Optimized Inlet Temperature (C) 400
430
Conversion
0.803
0.860
Catalyst Weight (kg)
503,000
228,175
Reactor Length
9.85
5.94
Percent Pressure Drop
8.54
9.97
Heat Gain (coolant)
1.27
1.66
Selectivity
0.326
0.319
Hmm catalyst weight or volume

20. Questions or Comments?