Improvement of lipophilic-amine-based thermomorphic biphasic solvent for energy-efficient carbon capture. Jiafei Zhang, David W.

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1 Shell s research project: Development of novel amine absorbents for CO 2 capture TCCS-6, Session A2 Topic: Post-combustion Solvents, David W. Agar Trondheim

2 Outline Motivation Concepts Solvent performance Challenges and amelioration Summary 1

3 Outline Motivation Concepts Global warming Shortcomings of conventional solvents Advantages of novel biphasic solvents Solvent performance Challenges and amelioration Summary 2

4 Motivation Challenges? New generation absorbents Technical shortcomings of conventional solvents: e.g. monoethanolamine (MEA) High energy consumption High quality of heat: C Significant amine loss by degradation Major superiorities of novel biphasic solvents: Regeneration temperature 80 C Use of waste heat for desorption Good chemical stability High net CO 2 loading capacity Wet CO 2 corrosion CO 2 + H 2 O HCO H + Anodic Fe Fe e - Catodic 2H + + 2e - 2H 0 Wet CO 2 corrosion CO 2 + H 2 O HCO H + Amine corrosion + Fe + 2RNH 3 Fe H 0 + 2RNH 2 3

5 Outline Motivation Concepts Solvent performance Lipophilic amine Phase change TBS absorbent Other CO 2 capture process with LLPS Challenges and amelioration Liquid-liquid phase separation (LLPS) (a) Homogeneous absorption (b) Heterogeneous desorption CO 2 Heating Organic phase R R 2 R 3 N + CO 2 + H 2 O R 1 R 2 R 3 NH HCO 3 3 R R 2 R 3 N + CO 2 + H 2 O R 1 R 2 R 3 NH HCO 3 3 Summary Cooling Aqueous phase CO 2 4

6 Concepts I Novel amines Alkanolamine vs lipophilic amine Hydrophobic Hydrophilic (H)R N R(H) (H)R N R(H) NH 2 R R OH Examples of lipophilic amine N H Hexylamine (I) HA Dipropylamine (II) DPA N N,N-Dimethylcyclohexylamine (III) DMCA 5

7 Concepts II Phase change Thermomorphic phase transition Low temperature single phase High temperature dual phases Lower critical solution temperature (LCST) Temperature [ C] Hexylamine (I) A1 DPA (II) DMCA (III) Frozen Two phases 0 Single phase Expected -20 0,0 0,2 0,4 0,6 0,8 1,0 Mass fraction of lipophilic amine in aqueous solution [g/g] 6

8 Concepts III Novel absorbent: thermomorphic biphasic solvent (TBS) Absorption: single phase Regeneration: two phases Lean solvent cooling to C: homogeneous Rich solvent heating to C: biphasic (a) Homogeneous absorption (b) Heterogeneous desorption CO 2 Heating Organic phase R R 2 R 3 N + CO 2 + H 2 O R 1 R 2 R 3 NH HCO 3 3 R R 2 R 3 N + CO 2 + H 2 O R 1 R 2 R 3 NH HCO 3 3 Aqueous phase Cooling CO 2 Process Flow Sheet 7

9 Concepts IV Other CO 2 capture process with LLPS Self-Concentration CO 2 Capture Process Univ. of Kentucky DMX TM process with demixing solvents IFP Energies Nouvelles Heat Ref.: Hu, 2010 Annual NETL CO 2 Capture Technol. R&D Meeting. Lemaire, et al., 12th Intl. Network for CO 2 Capture,

10 Outline Motivation Concepts Solvent performance Challenges and amelioration Amine selection Absorption Desorption Chemical stability Summary 9

11 Screening tests searching new amines > 50 lipophilic amines (alkylamines) < 10 comparable to MEA or MDEA Criteria High loading capacity: > 0.7 mol/mol (20% CO 2 ) Fast absorption rate: comparable to MEA Good regenerability: better than MDEA Low degradability: comparable to AMP & MDEA Moderate heat of reaction: lower than MEA Solvent performance I HN DPA N A: partially soluble in water, rapid absorption rate B: less miscible with water, high regenerability DMCA Recommended absorbent: Solvent blend A+B A: as absorption activator e.g. DPA, A1 B: as regeneration promoter e.g. DMCA, EPD Blending A+B exploits the strengths of both components N EPD 10

12 Solvent performance II Absorption Reactivity Rapid reaction rate Comparable to MEA (when α<0.5) Loading of CO 2 [mol CO 2 / mol amine] 1,0 0,8 0,6 0,4 0,2 A1 MEA MDEA+MEA 0, Time [min] Loading capacity (net) Alkanolamine C w/ steam stripping TBS absorbent C w/o steam stripping CO 2 absorbed in TBS: 3.4 mol/kg Higher than MEA and AMP mol -CO2 /kg -sol 11

13 Solvent performance III Desorption Liquid-liquid phase separation Low regeneration temperature ca. 80 C Low value heat Before regeneration During regeneration After regeneration High regenerability > 80% at 80 C for most TBS > 98% at 80 C for optimised TBS Estimated energy consumption MEA: 4.0 GJ/t -CO2 TBS: 2.5 GJ/t -CO2 Ref.: Geuzebroek, et al., TCCS-5,

14 Solvent performance IV Cyclic loading capacity Higher CO 2 loading Lower residual loading Better than benchmarks P CO2 (mbar) DMX-1, 40 C A1+DsBA, 30 C A1+DsBA, 80 C MEA 30wt%, 40 C MEA 30wt%, 120 C Loading (mol -CO2 /kg -sol. ) Chemical stability Low temperature (80 C) for desorption less thermal degradation Low oxidability less oxidative degradation Percent [%] Ref.: Raynal et al., 2010 (DMX-1 ) Basicity reduction by oxidative degradation Reactivity reduction by CO 2 induced degradation Reactivity reduction by oxidative degradation Reactivity reduction by catalyzed oxidative degradation B1 A1 MEA B1 A1 MEA MDEA Solvent 13

15 Outline Motivation Concepts Solvent performance Challenges and amelioration Summary Vaporisation loss Phase transition Regeneration techniques Process development 14

16 Challenges and amelioration I Amine vaporisation loss High volatility Significant volatile loss Amine Temp. Loss A1 DMCA DMCA+A1 (3:1) C %/day 30 < MEA AMP Countermeasures T for feed (top) at 30 C Reduced vaporisation Hydrophobic solvent scrubbing e.g. Diphyl Recovery >80% Water wash when using A1 as primary solvent Reduced amine loss Comparable to MEA or AMP 15

17 Challenges and amelioration II Phase transition Temperature ( C) Lower critical solution temperature (LCST): most lipo. Amines < 20 C Problem: biphasic solvent in absorber PTT of DMCA+A1 with 9wt% AMP CST of DMCA+A1 with 9wt% AMP PTT of DMCA+A1 CST of DMCA+A1 Two phases 3M(2:1) 3M(1:1) 4M(2:1) 4M(1:1) Concentration (mol/l) emulsion emulsion Single phase PTT: phase transition temperature CST: critical solution temperature Countermeasures Concentrating Negative on vaporisation loss Limited at 4M Using more A1 Negative on regeneration LCST 20 C Partial deep regeneration Residual loading 0.1 Increasing LCST to 30 C Adding solubiliser <10wt% Increasing LCST to 40 C 16

18 Challenges and amelioration III Regeneration techniques Challenges Regeneration intensification Low temperature 80 C Without steam How to intensify the regeneration? + Regeneration promoter Agitation Nucleation Nucleation + Agitation 17

19 Challenges and amelioration III Regeneration techniques 2,0 Solution: A1+B1, 2+1M at 75 C 1,6 Agitation Nucleation Stirring Desorber CO 2 (mol/l) 1,2 0,8 750 rpm 0,4 500 rpm 250 rpm N 2 stripping 0, Time (min) Desorber CO 2 (mol/l) 2,0 1,6 1,2 0,8 0,4 Solution: A1+B1, 2+1M at 75 C 0, Time (min) 1/40 wt. 1/60 wt. 1/80 wt. N 2 stripping Porous particles for CO 2 bubble formation CO 2 release rate [g/l/hr] DMCA+A1 DMCA+DPA Agitation none 100 rpm 250 rpm 500 rpm 750 rpm 1000 rpm Stripping Method 18

20 Challenges and amelioration IV Process development Regeneration without steam stripping Flow sheeting diagram 19

21 Challenges and amelioration V Bench-scale experimentation in packed absorption columns Absorber Regenerator Bottom of absorber At TU Dortmund At Shell G.S. 20

22 Summary Novel absorbent: lipophilic amine TBS Rapid absorption rate (due to activator A) High regenerability (due to regeneration promoter B) Excellent net CO 2 loading capacity Low energy requirement High chemical stability Novel concept: phase transition LLPS enhanced regeneration Regeneration at 80 C use of waste heat reduces CO 2 capture process costs 21

23 Acknowlegement biphasic solvent for energy-efficient carbon capture CO 2 Capture Research Group: M.Sc. TU Dortmund University Dr. Frank Geuzebroek Ir. Mark Senden Dr. Xiaohui Zhang Shell Global Solutions Int. B.V. Technical Staff: Michael Schlüter Julian Gies Jerzy Konikowski Students: Robert Misch, Jing Chen Yu Qiao, Wanzhong Wang Onyekachi Nwani Trondheim

24 End Thank you for your attention Jiafei ZHANG Emil-Figge-Str. 66 (TCB) D Dortmund, Germany Tel.: (+49) TCB Campus of TU Dortmund