1. Kinetic and Thermodynamic Data for MEA and MEA/PZ By: Ross Dugas January 11, 2008

2. Scope of the Presentation Introduction to MEA/PZ Introduction to MEA/PZ Objectives Objectives Background on Mass Transfer Background on Mass Transfer Apparatus - Wetted Wall Column Apparatus - Wetted Wall Column Kinetic and Thermodynamic Comparisons Kinetic and Thermodynamic Comparisons MEA and MEA/PZ systems MEA and MEA/PZ systems Conclusions Conclusions Future Work Future Work

3. Why use 7m MEA/2m PZ? Faster rates – kinetics Faster rates – kinetics Less packing Less packing Richer solutions Richer solutions Lower energy requirements Lower energy requirements Increased capacity – VLE Increased capacity – VLE Lower liquid flow rates Lower liquid flow rates Lower energy requirements Lower energy requirements

4. MEA/PZ/CO 2 Reactions 2 Monoethanolamine (MEA)MEA CarbamateProtonated MEA Piperazine (PZ)Protonated PZ Carbamate

5. Objectives Measure kinetics and equilibrium of 7m MEA and 7m MEA/2m PZ solutions over a wide range of CO 2 loadings Measure kinetics and equilibrium of 7m MEA and 7m MEA/2m PZ solutions over a wide range of CO 2 loadings Absorber Conditions (40, 60˚C) Absorber Conditions (40, 60˚C) Stripper Conditions (80, 100˚C) Stripper Conditions (80, 100˚C) Model data using Aspen RateSep Model data using Aspen RateSep

6. Mass Transfer with Chemical Reaction

7. Notes on Mass Transfer CO 2 absorption is liquid film controlled CO 2 absorption is liquid film controlled Generally Generally Rates dependent on √k 2 Rates dependent on √k 2 Effective mass transfer will not increase by √[Am] Effective mass transfer will not increase by √[Am] D CO2 and H CO2 change with [Am] D CO2 and H CO2 change with [Am] Mass transfer rates dependent on wetted area Mass transfer rates dependent on wetted area Not k l o or film thickness Not k l o or film thickness Liquid holdup has a very small effect on rates Liquid holdup has a very small effect on rates Special Conditions Special Conditions May be k l o controlled – instantaneous reaction or diffusion of reactants and products May be k l o controlled – instantaneous reaction or diffusion of reactants and products At long contact times At long contact times At high loading, high temperature, fast reagents, low k l o (viscosity) At high loading, high temperature, fast reagents, low k l o (viscosity)

11. + Hilliard ● Jou (1995) ▲ Dugas

12. ● Hilliard ▲ Dugas

14. ● Aboudheir – Laminar Jet Absorber ▲ Dugas – Wetted Wall Column

15. ● 7m MEA/2m PZ ▲ 7m MEA

16. Conclusions VLE measurements from Dugas, Hilliard, and Jou (1995) matched for 7m MEA over a wide range of CO 2 loadings. Dugas and Hilliard agree for 7m MEA/2m PZ. VLE measurements from Dugas, Hilliard, and Jou (1995) matched for 7m MEA over a wide range of CO 2 loadings. Dugas and Hilliard agree for 7m MEA/2m PZ. 7m MEA/2m PZ has about 45% greater CO 2 capacity. 7m MEA/2m PZ has about 45% greater CO 2 capacity. Discrepancies in Dugas and Aboudheir (2002) rate data can probably be explained by mass transfer phenomenon. Discrepancies in Dugas and Aboudheir (2002) rate data can probably be explained by mass transfer phenomenon. 7m MEA/2m PZ shows slightly faster rates than 7m MEA. 7m MEA/2m PZ shows slightly faster rates than 7m MEA.

17. Future Work Reconcile differences with Aboudheir MEA data Reconcile differences with Aboudheir MEA data Obtain more rate data for 7m MEA, 7m MEA/2m PZ and PZ systems Obtain more rate data for 7m MEA, 7m MEA/2m PZ and PZ systems Absorber conditions (40 and 60˚C) Absorber conditions (40 and 60˚C) Stripper conditions (80 and 100˚C) Stripper conditions (80 and 100˚C) Explore other MEA/PZ systems Explore other MEA/PZ systems Effect of total concentration, MEA:PZ ratios Effect of total concentration, MEA:PZ ratios Measure diffusion coefficients of MEA and PZ species Measure diffusion coefficients of MEA and PZ species Model the WWC with Aspen RateSep using experimental data Model the WWC with Aspen RateSep using experimental data

18. Questions? Ross Dugas ross@che.utexas.edu