Richard D. Noble. Douglas L. Gin. Alfred T. & Betty E. Look Professor of Chemical Engineering. Chemistry/ChBE Dept.

Transcription

1 CO 2 Separations Using Room Temperature Ionic Liquids and Membranes Richard D. oble Alfred T. & Betty E. Look Professor of Chemical Engineering Douglas L. Gin Chemistry/ChBE Dept.

2 Ionic Liquids

3 Imidazolium-based Room Temperature Ionic Liquids (RTILs) Organic salts Become liquid at or below 100 C on-flammable egligible vapor pressure Thermally stable above 200 o C Polymerizable versions [emim] High CO 2 solubility Good CO 2 / 2 solubility selectivity [Tf 2 - ]

4 Henry s Constants (H) of CO 2, CH 4, and 2 at 40 C α = 25 RTILs CO 2 CH 4 2 [emim][dca] [emim][tf 2 ] [emim][cf 3 SO 3 ] [hmim][tf 2 ] ILs Work by Solubility Selectivity

5 Amine Functionalized RTILs & RTILs with Free Amines

6 Amine Functionalized RTIL/RTIL Mixture H 2 Tf 2 H 2 (CH 2 ) 3 mmim Tf 2 Tf 2 hmim Tf 2

7 Happ (atm) 65.5 mole % [hmmim] [Tf2]/34.5 mole% [H 2 (CH 2 ) 3 mmim][tf 2 ] Time (min) α = 250

8 CO 2 Unloaded vs Loaded for a 50/50 mole % Mixture of MEA/[hmim][Tf 2 ]

9

10 RTIL-Amine Technology Exchange the water-amine solution with a RTIL-amine solution Reduces energy needed to heat solution by 1/3 to 1/2 Eliminates the energy lost to water evaporation RTILs do not evaporate Protects amine against oxidation/vapor press. loss

11 Membranes/Morphologies

12 CO 2 / 2 Permselectivity Robeson Plot for CO 2 / 2 Region Attractive to Industrial Use 10.0 Flux selectivity trade-off Polymer membranes CO 2 Permeability (Barrers)

13 Membrane Terminology Flux = moles/(surface area time) = J J = (D S) ΔP L Permeability = (D S) Permeance = (D S) = Material Prop L Thickness

14 Membrane Terminology Permeability = (D S) Barrer Permeance = (D S) GPU 10 Barrer/0.1 micron = 100 GPU L

15 First-Generation Poly(RTIL) Gas Separation Membranes Synthesize RTIL monomers of the following types in two or three simple steps: O R 1 R 2 O Tf 2 R 1 = Me, Bu, Hx Tf 2 R 2 = Me, Bu Polymerize into (lightly crosslinked) films

16 eat polymerized RTIL no free RTIL O O O Tf Tf Tf Tf - Gemini vinylimidzolium - PES support

17 CO 2 / 2 Permselectivity Robeson Plot for CO 2 / 2 First generation poly(rtil) membranes SILMs Region Attractive to Industrial Use Styrene-based Acrylate-based Flux selectivity trade-off CO 2 Permeability (Barrers) Polymer membranes SILMs

18 Poly(RTILs) w/ Pendant Groups Tf 2 Tf 2 O O O Tf 2 Tf 2

19 CO 2 / 2 Permselectivity Poly(RTILs) Above Upper Bound SILMs Region Attractive to Industrial Use Poly (RTILs) PEG-Poly(RTILs) itrile-poly(rtils) Flux selectivity trade-off Polymer membranes SILMs CO 2 Permeability (Barrers)

20 Polymer RTIL Composites While poly(rtils) have good CO 2 separation properties, they have low P (D). Combine polymerizable imidazolium salts w/ non-polymerizable RTILs to improve diffusion? Tf 2 80% 20% Tf 2

21 Polymerizable RTIL + free RTIL O O O + Tf Tf 33 wt% Tf Tf Tf Tf 67 wt% o support On PES support

22 CO 2 / 2 Permselectivity Improved Permeability SILMs Region Attractive to Industrial Use Polymer RTIL Composite PEG-Poly(RTILs) itrile-poly(rtils) Flux selectivity trade-off Polymer membranes SILMs CO 2 Permeability (Barrers)

23 Gels: Solid etworks Physical Gel physically bonded network hydrogen bonding, van der Waals interactions, and π-π bond stacking sol-gel thermal transition

24 CO 2 / 2 Permselectivity Gel Membranes: Liquid-Like Permeability SILMs Region Attractive to Industrial Use Hmim/Tf 2 bulk Hmim/Tf 2 gel bulk Hmim/Tf 2 Supor supported Hmim/Tf2 gel Supor supported Poly(RTILs) Polymer membranes SILMs CO 2 Permeability (Barrers)

25 Membrane Terminology Permeability = (D S) Barrer Permeance = (D S) GPU L 10 Barrer/0.1 micron = 100 GPU (commercial polymer membrane) 1000 Barrer/0.1 micron = 10,000 GPU (gel membrane)

26 Figure 1: Effect of membrane CO 2 / 2 selectivity on the cost of capturing 90% of the CO 2 in flue gas for membranes with a CO 2 permeance of 1000, 2000, and 4000 gpu at a fixed pressure ratio of 5.5 4

27 Opportunities Ionic Liquid Design Different Morphologies Facilitated Transport Specific CO 2 Separations CO 2 / 2 post combustion (low P) CO 2 /H 2 precombustion (high T) CO 2 /CH 4 natural gas (high P)

28 Looking Ahead

29 Fabrication of SAPO 34 Poly(IL) Composite Membranes SAPO nm UV light crosslinker Tf 2 poly(il) Tf 2 [emim][tf 2 ] 100 nm 10 wt% of SAPO-34 & (80-20)wt% of styrene poly(il) and [emim][tf 2 ] composite membrane Hudiono, Y.C., et.al., J. Membr. Sci. 2010(in pr 29

30 P(CO 2 )/P(CH 4 ) P(CO 2 )/P( 2 ) CO 2 /CH 4 & CO 2 / 2 Using 3- component Mixed Matrix Membranes 100 Increasing SAPO-34 loadings 100 (100-0) (60-40) (80-20) (60-40) (40-60) (100-0) (80-20) (40-60) P(CO 2 ) (Barrers) P(CO 2 ) (Barrers)

31 Imidazolium-Based Cationic Polymer Architectures Previously synthesized poly(imidazolium) architectures Rare or unprecedented poly(imidazolium) architectures (Radosz) (only 3 prior examples) (Bara, oble, Gin) (Ohno, Kato)

32 Ionene Membranes Ionene: main-chain polycation Imidazolium-based ionenes: R 1 + X R 2 X R 1 R 2 X X X = halide n R 1, R 2 = O O

33 Composites with anostructure Liquid crystals based on imidazolium salts can form ordered materials with nanometer scale pores filled with RTILs or other non-organic solvents C 12 BF 4 BF 4 O C wt% BF 4

34 Phase Behavior of Other Imidazolium Gemini LLCs Br Br 4 (1/ 6) wt % Br 3 Type I Q 230 (Ia3d) RTIL (1/ 8) RTIL Type I Q 224 (Pn3m) 2 (degrees) BF 4 O BF wt % RTIL BF 4 4 RTIL (Jason Bara) Preferred LLC phase depends on choice of anion, bridge, and tail type

35 Composite Ionic Liquid Structures Will Provide High Selectivity Liquids High Permeabiltiy & Selectivity Membranes Huge Range of Materials Issues: Coating (Thickness) Mechanical Properties

36 SUMMARY Amine addition provides an order of magnitude increase in CO 2 loading and selectivity. Polymers synthesized that exceed the upper bound on Robeson plot. Composite structures provide enhanced P and maintain α. Gel membranes provide liquid-like P and maintain α.

37 Finish

38 The University of Colorado