CO 2 adsorption using CaO and its potential integration with - - PowerPoint PPT Presentation

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CO 2 adsorption using CaO and its potential integration with - - PowerPoint PPT Presentation

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CO 2 adsorption using CaO and its potential integration with hydrogen production from biomass gasification Dr Chunfei Wu University of Hull 25/10/2017 Outline Introduction Experimental Results and discussions Conclusion Introduction -

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CO2 adsorption using CaO and its potential integration with hydrogen production from biomass gasification

Dr Chunfei Wu University of Hull 25/10/2017

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Outline

Introduction Experimental Results and discussions Conclusion

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Introduction - background

U.S. National Climate Assessment (2014)

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CO2 capture using CaO-based materials

CO2 adsorption  CaCO3 CO2 desorption  CaO 400 - 600 ºC ~800 ºC

  • High temperature required for regeneration
  • Material movement is required, thus better

mechanical strength needed

  • Still have challenges for the treatment of the

adsorbed CO2

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Our approaches

CO2 adsorption  CaCO3 CO2 desorption  CaO

~400 ºC <400 ºC

H2 CH4 , CO etc.

  • System integration
  • No material movement
  • CO2 utilised

Renewable energy Hydrogen storage

Ca-based composite catalyst

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Introduction - CO2 solid adsorbent

The application of different types of adsorbents at different temperature

ChemSusChem.2009,2:796-854.

high theoretical adsorption capacity low cost

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Introduction – deactivation of CaO

Schematic description of the transformation of a calcium

  • xide adsorbent in recarbonation/decomposition cycles

AIChE Journal.2007,53:2432-2442.

  • Ind. Eng. Chem. Res. 2006, 45, 8846 –8851.

CaCO3 CaO

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Methods to improve CaO-based adsorbents

Energy Environ. Sci., 2014, 7, 3478-3518

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Objectives and experimental work

Focused ion beam (FIB)/SEM energy-dispersive X-ray spectroscope (EDXS)

Detailed analysis of CO2 capture using CaO adsorbent CaCO3 product layer thickness investigation

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Results-Porosity analysis

0.0 0.2 0.4 0.6 0.8 1.0 20 40 60 80 100 P / P0 Quantity Adsorbed/cm

3·g

  • 1 STP

CaO sol-gel CaO 1 10 100 0.00 0.04 0.08 0.12 0.16 0.20 dp / nm dv/dlog(w)/cm

3·g

  • 1

CaO sol-gel

Samples SBET Smicro Smeso Vp Vmicro Vmeso (m2 g-1) (m2 g-1) (m2 g-1) (cm3 g-1) (cm3 g-1) (cm3 g-1) CaO 20.96 3.70 17.26 0.0314 0.0014 0.0331 sol-gel CaO 38.51 8.51 30.01 0.1527 0.0035 0.1511

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SEM analysis

CaO sol-gel CaO

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TEM analysis

CaO sol-gel CaO

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Fixed bed adsorption (1)

0.0 2.0k 4.0k 6.0k 8.0k 10.0k 12.0k 14.0k 5 10 15 20 25

800 oC 600 oC

CaO CO2% Time / s

400 oC

  • 2.0k

0.0 2.0k 4.0k 6.0k 8.0k 10.0k 12.0k 14.0k 10 20 30 40 50

800 oC 600 oC 400 oC

CO2% Time / s sol-gel CaO

CO2 capture performance of different adsorbents in the fixed bed test (left: CaO, right: sol-gel CaO) under 15% CO2

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Fixed bed adsorption (2)

CO2 capture performance of different adsorbents in the fixed bed test (left: CaO, right: sol-gel CaO) under 40% CO2

1000 2000 3000 4000 5000 10 20 30 40 50 60 600

  • C

800

  • C

CaO

CO2 % Time / s 400

  • C

1000 2000 3000 4000 5000 10 20 30 40 50 60 800

  • C

600

  • C

400

  • C

Time / s CO2 %

sol-gel CaO

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200 400 600 800 1000 75 90 105 120 135 150

CaO t-f

Temperature /

  • C

weight / % 200 400 600 800 1000 75 90 105 120 135 150 Temperature /

  • C

weight / %

CaO t-s

200 400 600 800 1000 75 90 105 120 135 150

sol-gel CaO t-f

Temperature /

  • C

weight / % 200 400 600 800 1000 75 90 105 120 135 150

sol-gel CaO t-s

Temperature /

  • C

weight / %

TGA test of CO2 capture performance at temperature fixed and temperature swing process （CO2 partial pressure: 15%）

TGA adsorption (1)

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TGA adsorption (2)

200 400 600 800 1000 75 90 105 120 135 150 Temperature /

  • C

weight / %

CaO t-f

200 400 600 800 1000 75 90 105 120 135 150 weight / % Temperature /

  • C

CaO t-s

200 400 600 800 1000 75 90 105 120 135 150

sol-gel CaO t-f

Temperature /

  • C

weight / % 200 400 600 800 1000 75 90 105 120 135 150

sol-gel CaO t-s

Temperature /

  • C

weight / %

TGA test of CO2 capture performance at temperature fixed and temperature swing process （CO2 partial pressure: 100%）

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10 20 30 40 50 60 70 80

 

  • CaCO3

 CaO

   

  • FB-des

FB-600 FB-400

Intensity / a.u. 2Theta / degree

CaO

10 20 30 40 50 60 70 80

     

  • sol-gel FB-des

sol-gel FB-600 sol-gel FB-400

2Theta / degree Intensity / a.u.

sol-gel CaO  CaO

  • CaCO3

XRD patterns of CaO adsorbents obtained after reaching highest reaction rate at different temperatures (left: CaO, right: sol-gel CaO).

XRD analysis

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FIB-SEM analysis (1)

SEM-EDX of CaO obtained at 600 ºC

80 nm

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FIB-SEM analysis (2)

SEM-EDX of sol-gel CaO obtained at 600 ºC

CaO

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CaO/KIT-6

10 20 30 40 50 60 70 80 Intensity 2 Theta/degree

CaO/KIT-6=0.5:1 CaO/KIT-6=1:1 CaO/KIT-6=2:1

0.0 0.2 0.4 0.6 0.8 1.0 10 20 30 40 50

CaO/KIT-6 0.5-1

CaO/KIT-6 1-1 CaO/KIT-6 2-1 Quantity absorbed / (cm

3 g

  • 1) STP

P / P0

Samples SBET/ Smicro/ Smeso/ Vp/ Vmicro/ Vmeso/ dave/ (m2/g) (m2/g) (m2/g) (cm3/g) (cm3/g) (cm3/g) nm KIT-6 545.83 265.42 280.41 0.4066 0.1105 0.2892 29.8 CaO/KIT/6 0.5-1 16.43 1.96 14.47 0.0768 0.0012 0.0773 18.7 CaO/KIT/6 1-1 8.29 1.78 6.51 0.0291 0.0008 0.0288 14.0 CaO/KIT/6 2-1 2.12 0.64 1.48 0.0001 0.0003 0.0008 0.28

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10 20 30 40 50 12 13 14 15 16 600

  • C

400

  • C

CaO/KIT-6=2:1

t / min CO2 / %

CaO/KIT-6 for CO2 capture

400 800 1200 1600 98 100 102 104 106 108 Weight / % Time / min

CaO/KIT-6=0.5:1 CaO/KIT-6=1:1 CaO/KIT-6=2:1

Two temperature windows for CO2 adsorption are observed 10 stable cycles of CO2 adsorption/desorption

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Ni-CaO-based composite catalyst

Syngas (~600°C) CO2 capture (~400°C) Biomass gasification Regenerated material High purity and clean syngas CO2 release & hydrogenation (~350 °C) CO2 saturated material Energy storage processes H2 Excess electricity or Wind farm

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Ni-CaO/KIT-6 catalyst

10 20 30 40 50 60 70 80 Intensity 2 Theta / degree

Ni/CaO/KIT-6 0.5-1

Ni/CaO/KIT-6 1:1 Ni/CaO/KIT-6 2:1

0.0 0.2 0.4 0.6 0.8 1.0 20 40 60 80 100 P / P0 Quantity absorbed / (cm

3 g

  • 1) STP

Ni/CaO/KIT-6 0.5-1

Ni/CaO/KIT-6 1-1 Ni/CaO/KIT-6 2-1 200 400 600 800 1000 1200 80 84 88 92 96 100 104 temperature / oC weight / %

Ni/CaO/KIT-6 0.5:1 Ni/CaO/KIT-6 1:1 Ni/CaO/KIT-6 2:1

XRD TPR Pore volume

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500 1000 1500 2000 2500 3000 0.10 0.15 0.20 0.25 0.30 0.35 CH4 H2 Time / s CH4 % 1.5 2.0 2.5 3.0 3.5 4.0 4.5 H2 %

Methanation of adsorbed CO2

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Conclusions

  • Porous structure is beneficial for CO2 capture
  • CaO-based adsorbents have two temperature

windows for CO2 capture – 400 and 600 ºC

  • Measured thickness of the CaCO3 layer is between

80 and 170 nm for the first stage fast adsorption

  • Developing nano-CaO with dimension less than

the critical thickness will be promising. The sintering of CaO needs to be considered

  • Integrate CO2 capture and utilisation could be

promising

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Thank you for your attention!