Partial Oxidation of Benzene to Maleic Anhydride

1. Partial Oxidation of Benzene to Maleic Anhydride Derek Becht Mike Raymond Eric Nette Matt Hunnemeder

2. Overview • Project Description • Background • Assumptions • Solution Methodology • Final Design • Overall Comparison

3. Project Description • Reaction: Partial oxidation of benzene • Reactor: Fixed bed reactor • Production: 50000 M tons/year maleic anhydride • Step by step modeling process Fogler H.S. Elements of Chemical Reaction Engineering; Pearson Education: New Jersey, 2006.

4. Maleic Anhydride

5. Financial Considerations • Market Price3,4 • Maleic Anhydride: $1.54/kg - $ 1.70/kg • Benzene: $929.99/m3 – $940.55/m3 • Financial Earnings • $20,922,183/yr neglecting all cost, except feed

6. Standard Assumptions • Open system + steady state • Negligible potential and kinetic energy • No mechanical or shaft work • Turbulent flow • Uniform temperature, pressure, and concentration within the control volume • 2 weeks downtime

7. Benzene Specific Assumptions • 1.1 mol % inlet benzene5 • Conversion, XB, is 0.76 6 • Dry air • Negligible CO2 in air A. Bielanski, M. N. (1997). V2O5-MoO3 Catalysts for Benzene Oxidation. Applied catalysts , 223-261.

8. Reactor and Particle Properties • Bulk Density7 = 930 kgcat/m3 • V2O5-MoO3 Particle Diameter8 = 0.006m • Void Fraction = 0.4 m3gas/m3rxtr • Heat Transfer Coefficient8 = 202.4 W/m2-K • Coolant Temperature8 = 653 K

9. Solution Methodology • Ideal Reactor -> Realistic Reactor • Considerations: • Pressure drop • Side reactions • Temperature rise/drop

10. Case 1: Ideal Reactor • Assumptions Reaction Kinetics • Isothermal • One reaction • Isobaric • Inlet Conditions Feed Rates • 658 K Benzene: 0.02122 kmol/s • 1.5 atm Oxygen: 0.4177 kmol/s • 1.1 mol% benzene Nitrogen: 1.577 kmol/s

11. Conversion Profile

12. Heat Duty Profile

13. Case 2: Pressure Drop • Additional Assumptions Momentum Equations • Ideal Gas • Constant Density • Additional Property • Viscosity9 = 3.2197E-5 PaS

14. Conversion Profile

15. Particle Diameter

16. Case 3: Multiple Reactions • Mechanism Rate Expressions 2 C6H6 + 6 O2 -> 3 C4H2O3 + 3 H2O C6H6 + 6 O2 -> 3 CO + 3 CO2 + 3 H2O

17. Molar Flow Rates

18. Selectivity

19. Case 4: Energy Balance • Additional Assumptions • Constant heat capacity • Constant coolant temperature • Multi-tube reactor

20. Coolant Temperature

21. Inlet Temperature

22. Final Design: Optimization • Pressure • Temperature

23. Overall Comparison

24. References 1) Barone et al., United States Patent 4018709. Patent Issued 1977. 2) Maleic anhydride - Chemical Profile. <http://www.the-innovation-group.com/ChemProfiles/Maleic%20Anhydride.htm>. (accessed 01/24/2008). 3) William Lemos. US Price Report – Maleic Anhydride. <http://www.icis.com/v2/chemicals/9076024/maleic-anhydride/pricing>. (accessed 01/25/2008). 4) Americas Market Summary – Benzene. http://www.icis.com/articles/2008/01/29/9096633/NOON-SNAPSHOT. (accessed 01/24/2008). 5) Sharma R.K. et al. (1984). Selective Oxidation of Benzene to maleic anhydride at Commercially Relevant Conditions. Institution of Chemical Engineers Symposium Series, 353-360. 6) Americas Market Summary – Benzene. http://www.icis.com/articles/2008/01/29/9096633/NOON-SNAPSHOT. (accessed 01/24/2008). 7) U.S. Patents. (1996). Oxide catalyst and process for producing maleic anhydride by oxide catalyst (No. 266510 filed on 1994-06-27). 8) U.S. Patents. (1978). Process for the Manufacture of Maleic Anhydride (No. 4070379 filed on 10/21/1976). http://www.freepatentsonline.com/4070379.html 9) Chemical Database Property Constants. DIPPR Database [Online]. Available from Rowan Hall 3rd Floor Computer Lab. (Accessed on 1/24/2008).

25. Questions and Comments?