© 2010 Aspen Technology, Inc. All rights reserved Brian Hanley, Principal Engineer March 23, 2010 Packed Column Hydraulics and Continuous Phase Transitions AIChE 2010 Spring Meeting San Antonio, TX
© 2010 Aspen Technology, Inc. All rights reserved | 2 Introduction Packed columns undergo a transition from vapor- to liquid- continuous operation. The transition is a “second order” (continuous). Examples include: –Percolation threshold in random resistor networks –Paramagnetic/ferromagnetic transition at the Curie point Phase transitions exhibit universal behavior. –Universality classes These observations can be can be used as a basis for correlating pressure drops/flood point in packed columns.
© 2010 Aspen Technology, Inc. All rights reserved | 3 Packed Columns and Resistor Networks Two Characteristic Resistances in Each Problem R1R1 R2R2
© 2010 Aspen Technology, Inc. All rights reserved | 4
5 Phase Transitions & Renormalization I P-V-T Behavior of Pure Fluids – “Corresponding States” © J.M. Yeomans, Statistical Mechanics of Phase Transitions, Oxford University Press, 1993
© 2010 Aspen Technology, Inc. All rights reserved | 6 Phase Transitions & Renormalization II Ferromagnetic/Paramagnetic Transition © J.M. Yeomans, Statistical Mechanics of Phase Transitions, Oxford University Press, 1993
© 2010 Aspen Technology, Inc. All rights reserved | 7 Is There a Phase Transition for Packed Columns?
© 2010 Aspen Technology, Inc. All rights reserved | 8 Renormalization Procedure Every liquid load curve contains a flood point Assume all curves belong to the same universality class
© 2010 Aspen Technology, Inc. All rights reserved | 9 Flooding & Renormalization I. Hydraulic Behavior of Glitsch Grid EF-25A
© 2010 Aspen Technology, Inc. All rights reserved | 10 Flooding & Renormalization II. Hydraulic Behavior of Intalox Structured Packing 3T
© 2010 Aspen Technology, Inc. All rights reserved | 11 Flooding & Renormalization III. Hydraulic Behavior of 1” Ceramic Raschig Rings
© 2010 Aspen Technology, Inc. All rights reserved | 12 Flooding & Renormalization IV. Nutter Ring #2 and Plastic Snowflake Packings
© 2010 Aspen Technology, Inc. All rights reserved | 13 “Corresponding States” for Packings I. Pressure Drop/Flood for FLEXIPAC Structured Packings
© 2010 Aspen Technology, Inc. All rights reserved | 14 “Corresponding States” for Packings II. Pressure Drop/Flood for ISP and Raschig Super Rings
© 2010 Aspen Technology, Inc. All rights reserved | 15 “Corresponding States” for Packings III. Pressure Drop/Flood for Several Different Packings
© 2010 Aspen Technology, Inc. All rights reserved | 16 “Corresponding States” for Packings IV. Pressure Drop/Flood for Several Different Packings
© 2010 Aspen Technology, Inc. All rights reserved | 17 “Corresponding States” for Packings V. Pressure Drop/Flood for Several Different Packings
© 2010 Aspen Technology, Inc. All rights reserved | 18 Some p Data Do Not Collapse Curves for different liquid loads do not belong to the same universality class
© 2010 Aspen Technology, Inc. All rights reserved | 19 The Wallis equation can be used to correlate flood data. The parameters “m” and “c” are known to depend on the physical properties of the liquid. Dimensional analysis can be used to show that: Extending Results to Other Systems Wallis Flood Correlation and Dimensional Analysis I.
© 2010 Aspen Technology, Inc. All rights reserved | 20 Extending Results to Other Systems Wallis Flood Correlation and Dimensional Analysis II.
© 2010 Aspen Technology, Inc. All rights reserved | 21 Comparison to Experiment I.
© 2010 Aspen Technology, Inc. All rights reserved | 22 Comparison to Experiment II.
© 2010 Aspen Technology, Inc. All rights reserved | 23 Correlation Available in Aspen Plus
© 2010 Aspen Technology, Inc. All rights reserved | 24 Conclusions Packed columns undergo a transition from vapor- to liquid- continuous operation. The transition is a “second order” (continuous). Packed column hydraulics exhibit universal behavior. –Universality classes –“Corresponding hydraulic states” Hydraulics for a given system “near” flood are dependent on a small number of features –Dimensionality –Symmetry –Connectivity but are otherwise insensitive to the underlying geometric and topological properties of the packing.