CO 2 adsorption using CaO and its potential integration with hydrogen production from biomass gasification

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1 CO 2 adsorption using CaO and its potential integration with hydrogen production from biomass gasification Dr Chunfei Wu University of Hull 25/10/2017

2 Outline Introduction Experimental Results and discussions Conclusion

3 Introduction - background U.S. National Climate Assessment (2014)

4 CO 2 capture using CaO-based materials CO 2 adsorption CaCO 3 CO 2 desorption CaO 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 CO 2

5 Our approaches Ca-based composite catalyst CO 2 adsorption CaCO 3 CO 2 desorption CaO ~400 ºC <400 ºC Renewable energy Hydrogen storage H 2 CH 4, CO etc. o System integration o No material movement o CO 2 utilised

6 Introduction - CO 2 solid adsorbent high theoretical adsorption capacity low cost The application of different types of adsorbents at different temperature ChemSusChem.2009,2:

7 Introduction deactivation of CaO CaCO 3 CaO Schematic description of the transformation of a calcium oxide adsorbent in recarbonation/decomposition cycles AIChE Journal.2007,53: Ind. Eng. Chem. Res. 2006, 45,

8 Methods to improve CaO-based adsorbents Energy Environ. Sci., 2014, 7,

9 Objectives and experimental work Detailed analysis of CO 2 capture using CaO adsorbent CaCO 3 product layer thickness investigation Focused ion beam (FIB)/SEM energy-dispersive X-ray spectroscope (EDXS)

10 Quantity Adsorbed/cm 3 g -1 STP dv/dlog(w)/cm Results-Porosity analysis CaO sol-gel CaO 3 g CaO sol-gel P / P dp / nm Samples S BET S micro S meso V p V micro V meso (m 2 g -1 ) (m 2 g -1 ) (m 2 g -1 ) (cm 3 g -1 ) (cm 3 g -1 ) (cm 3 g -1 ) CaO sol-gel CaO

11 SEM analysis CaO sol-gel CaO

12 TEM analysis CaO sol-gel CaO

13 CO 2 % CO 2 % Fixed bed adsorption (1) CaO 800 o C sol-gel CaO 800 o C o C 600 o C o C o C k 4.0k 6.0k 8.0k 10.0k 12.0k 14.0k Time / s -2.0k k 4.0k 6.0k 8.0k 10.0k 12.0k 14.0k Time / s CO 2 capture performance of different adsorbents in the fixed bed test (left: CaO, right: sol-gel CaO) under 15% CO 2

14 CO 2 % CO 2 % Fixed bed adsorption (2) CaO 50 sol-gel CaO o C 600 o C 800 o C o C 600 o C 800 o C Time / s Time / s CO 2 capture performance of different adsorbents in the fixed bed test (left: CaO, right: sol-gel CaO) under 40% CO 2

15 weight / % weight / % weight / % weight / % TGA adsorption (1) CaO t-f 135 CaO t-s Temperature / o C Temperature / o C sol-gel CaO t-f 135 sol-gel CaO t-s Temperature / o C Temperature / o C TGA test of CO 2 capture performance at temperature fixed and temperature swing process (CO 2 partial pressure: 15%)

16 weight / % weight / % weight / % weight / % TGA adsorption (2) CaO t-f 135 CaO t-s Temperature / o C Temperature / o C sol-gel CaO t-f 135 sol-gel CaO t-s Temperature / o C Temperature / o C TGA test of CO 2 capture performance at temperature fixed and temperature swing process (CO 2 partial pressure: 100%)

17 Intensity / a.u. Intensity / a.u. XRD analysis CaO CaCO 3 FB-des CaO CaCO 3 sol-gel FB-des FB-600 sol-gel FB-600 FB-400 sol-gel FB-400 CaO sol-gel CaO Theta / degree Theta / degree XRD patterns of CaO adsorbents obtained after reaching highest reaction rate at different temperatures (left: CaO, right: sol-gel CaO).

18 FIB-SEM analysis (1) 80 nm SEM-EDX of CaO obtained at 600 ºC

19 FIB-SEM analysis (2) CaO SEM-EDX of sol-gel CaO obtained at 600 ºC

20 Intensity Quantity absorbed / (cm 3 g -1 ) STP CaO/KIT CaO/KIT CaO/KIT CaO/KIT CaO/KIT-6=0.5:1 CaO/KIT-6=1:1 CaO/KIT-6=2: Theta/degree P / P 0 Samples S BET / S micro / S meso / V p / V micro / V meso / d ave / (m 2 /g) (m 2 /g) (m 2 /g) (cm 3 /g) (cm 3 /g) (cm 3 /g) nm KIT CaO/KIT/ CaO/KIT/ CaO/KIT/

21 CO 2 / % Weight / % CaO/KIT-6 for CO 2 capture o C CaO/KIT-6=2:1 600 o C CaO/KIT-6=0.5:1 CaO/KIT-6=1:1 CaO/KIT-6=2: t / min Time / min Two temperature windows for CO 2 adsorption are observed 10 stable cycles of CO 2 adsorption/desorption

22 Ni-CaO-based composite catalyst Biomass gasification High purity and clean syngas Syngas (~600 C) Regenerated material CO 2 capture (~400 C) CO 2 saturated material CO 2 release & hydrogenation (~350 C) H 2 Excess electricity or Wind farm Energy storage processes

23 weight / % Intensity Quantity absorbed / (cm 3 g -1 ) STP Ni-CaO/KIT-6 catalyst Ni/CaO/KIT Ni/CaO/KIT Ni/CaO/KIT Ni/CaO/KIT Ni/CaO/KIT-6 1:1 Ni/CaO/KIT-6 2: Theta / degree XRD P / P 0 Pore volume Ni/CaO/KIT-6 0.5:1 Ni/CaO/KIT-6 1:1 Ni/CaO/KIT-6 2: temperature / o C TPR

24 CH 4 % H 2 % Methanation of adsorbed CO CH 4 H Time / s

25 Conclusions Porous structure is beneficial for CO 2 capture CaO-based adsorbents have two temperature windows for CO 2 capture 400 and 600 ºC Measured thickness of the CaCO 3 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 CO 2 capture and utilisation could be promising

26 Thank you for your attention!