Pilot / lab scale study of CO 2 separation with ionic liquid blending

Transcription

1 12 June-14 June, 2017 Pilot / lab scale study of CO 2 separation with ionic liquid blending Dawei Shang, Xiangping Zhang, Suojiang Zhang Institute of Process Engineering, Chinese Academy of Sciences 1

2 Global warming and CCS Glaciers Melting CCS technologies Absorption Membrane PSA TSA Chemical absorbents Amino solutions Physical absorbents NHD Ionic liquids High gas solubility Good thermal stability Low heat capacity Negligible vapor pressure 2

3 Ionic Liquids: A New Generation of Medium Molten Salts NaCl (m.p. 800 o C), LiCl-KCl (m.p. 355 o C), NaCl-AlCl 3 (m.p. 107 o C) Ionic Liquids PF - BF N N R R 1 Liquid at RT Nonvolatile Designable Medium / Catalyst 3

4 Solubility (gco 2 /g IL) CCS with ionic liquids 0.20 Physical absorption [DAIL][Br] 0.15 [P 4443 ][Gly] 2012 (30 O C,0.1MPa) 0.10 [E 1 Py][Tf 2 N] 2014 (40 O C,1.93MPa) 2009 (25 O C,0.1MPa) [HEA][A] [Bmim][PF 6 ] (40 O C,1.56MPa) (40 O C,1.31MPa) [TMG][L] 2007 (35 O C,2.24MPa) Chemical absorption Energy Environ Science, 2012, 5: 6668; J Chem Eng Data, 2010, 55: 3513; Chem Eng J, 2014, 251: 248; Fluid Phase Equilibr, 2010, 297: 34; Ind Eng Chem Res, 2013, 52: 5835; Fluid Phase Equilibr, 2014; 365:80; Ind Eng Chem Res, 2014, 53: 16832; RSC Adv, 2015, 5: 2470 ; Applied Energy, 2015, 154:771. 4

5 Scale up for the CCS process of ILs 净化气 再生气 冷却器 新鲜溶剂 再生冷却器 溶剂泵 两级解吸塔 再生气分离灌 净化气分离器 气提再生塔 E-17 变换气 闪蒸气 煮沸器蒸汽 两段吸收塔 闪蒸灌 半贫液泵 溶液换热器 贫液泵 冷却器 补充离子液体 Molecular Cluster Unit operation System Scale up of CO 2 separation with ILs 5

6 Mass transfer of gases in ILs Solvents Viscosity (mpa S) k L 10 5 m/s [omim][bf 4 ] [bmim][bf 4 ] [bmim][dca] [bmim][no 3 ] H 2 O k at L 0 PCO 1 1 PCO P 2 ln 0 CO 2 2 Mass transfer coefficient depends on various factors, including viscosities and ILs structures AIChE J, 2014, 60: 2929; Ind Eng Chem Res, 2014, 53: 428 6

7 Bubble behavior in ILs and water Water ILs Water ILs Different bubble behaviors in water and ILs 7

8 CO 2 concentration Models of the bubble behavior Models modifications FCCS Dynamic process of CO 2 absorption CFD method [omim][bf 4 ][bmim][bf 4 ][bmim][no 3 ] 95%wt[bmim][BF 4 ] Chem Eng Sci, 2015, 135: 76 Chem Eng J, 2012, 209: 607; Ind Eng Chem Res, 2014, 53: 428 8

9 Process simulation and cost estimation Experimental and calculated heat capacities of ILs Effect of α lean on the regeneration thermal energy requirement of MEA and IL-based processes [Bpy][BF 4 ]- MEA process can save about 15% regeneration heat duty compared to the conventional MEA Modified process flow diagram for CO 2 capture with ILs-amine blending process. Ind. Eng. Chem. Res. 2014, 53:

10 CO 2 separation from syngas 10

11 Continuous apparatus for CO 2 capture 11

12 Continuous apparatus for CO 2 capture CO 2 detector Absorption tower Desorption tower CO 2 N 2 Rich solvents Lean solvents 12

13 Parameters and part results Component of the absorbent and the operating parameters Solvent Pressure Gas flow Fluid flow 27% MDEA 3% PZ (10% Ionic liquid) ~ 10 Bar CO L/h N L/h 2~5 L/h Amine solution Pressure (Bar) Liquid-gas ratio (L/h) 3.5/ /500 Average removal rate (%) Time (h) Regeneration energy (GJ/tCO 2 ) Outlet gas CO 2 concentration and 13 removal rate

14 IL-amine blending for CO 2 capture / Effect of pressure on the CO 2 removal rate Effect of temperature on the CO 2 removal rate Effect of liquid-gas ratio on the CO 2 removal rate Compared with amine solution, the regeneration energy of CO 2 from IL-amine blending was about 17.4% lower at the same CO 2 removal rate and the same parameters of the absorption tower. 14

15 CO 2 separation from landfill gas 15

16 CO 2 removal from landfill gas with IL blending 10m 3 / h of gas flow 16

17 CO 2 removal from landfill gas with IL blending 17

18 CO 2 removal from landfill gas with IL blending Component of the absorbent and the operating parameters Solvent Pressure Gas flow Fluid flow 90% NHD 10% Ionic liquid ~ 7 Bar ~1000 L/h (CO 2 ~33%, CH 4 ~40%) 420 L/h The adding of IL slightly decreased the CO 2 solubility but increased the selectivity of CO 2 / CH 4. 18

19 CO 2 separation from melamine industry tail gas 19

20 CO 2 / NH 3 separation with water 20

21 CO 2 / NH 3 separation with ILs 21

22 Designing of the ILs Types ILs Initial ph * pk a Conventional IL [Bmim][NTf 2 ] Protic IL [Bim][NTf 2 ] Brønsted acidic IL [HOOC(CH 2 ) 3 mim][ntf 2 ] * ph and pk a of ILs were measured in water and DMSO solution Structures of (a) [Bmim][NTf 2 ], (b) [Bim][NTf 2 ] and (c) [HOOC(CH 2 ) 3 mim][ntf 2 ] 22

23 Measuring apparatus and EOS Vapor-liquid equilibrium measurement apparatus: a, NH 3 ; b 1, b 3-5, ball valve; b 2, regulating valve; c 1, c 2, pressure sensor; d, gas reservoir; e, absorption vessel; f, magnetic stirrer; g, vacuum pump; h, water bath Equation of state: p RT a( T ) V b ( V b )( V b ) 23

24 Protic IL for NH 3 separation 2.69 mol NH 3 / mol IL 1.54 mol NH 3 / mol IL 0.28 mol NH 3 / mol IL Solubility of NH 3 in ILs at 313K NH 3 solubility in protic IL was about 1.7 times than carboxyl-functionalized IL and 10 times than conventional IL. 24

25 Possible absorption mechanism In-situ FTIR NMR Schematic for the possible mechanism of absorption of NH 3 by [Bim][NTf 2 ] Quantum chemistry calculation 25 Green Chem. 2017, 19,

26 NH 3 tail gas treatment apparatus Apparatus for 800M Nm 3 /a gas treatment 26

27 Acknowledgements These studies were financially supported by the National Natural Science Fund for Distinguished Young Scholars ( ) and the CLIMIT program and the Research Council of Norway (215732). 27

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