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09.11.2010
Novel Calcium-based regenerative sorbents for high-temperature
CO2 capture
Johann Mastin and Julien [email protected]
Institute for Energy TechnologyP.O. Box 40, 2027 Kjeller, NORWAY
www.ife.no
09.11.2010
CaO-looping for pre-combustion CO2 capture: H2 production via SE-SMR
09.11.2010
The ZEG - technology• Co- production of electricity and hydrogen with integrated CO2 -capture• Electricity from high temperature solid oxide fuel cells (SOFC)• Hydrogen production by sorption enhanced steam methane reforming (SE-SMR)• High total energy efficiency
“Techno-economical study of the zero emission gas power concept (ZEG)”J.Meyer, J.Mastin, T-K Bjørnebøle, T. Ryberg, N. Eldrup. GHGT-10
09.11.2010
An “ideal” high-temperature sorbent for pre-combustion CO2 capture…
• Elevated CO2 absorption capacity• High reaction kinetics even at low CO2 partial pressure• Long-term stability during carbonation-calcination cycles• High chemical stability (inert and stable)• Good mechanical stability• Largely available at low cost
09.11.2010
100 200 400300 500 600 700 800 900
Abs
orpt
ion
Cap
acity
Temperature (oC)
High-temperature CO2 sorbents
hydrotalcite
Na2 ZrO3
Li2 ZrO3
Li4 SiO4
Calcium-basedsorbents
Amine solvent
Carbonate solvent
Carbonate sorbents
09.11.2010
• Loss-in-absorption capacity during multi-cycling• Poor mechanical stability (particle breakage)• Sulphur removal is often needed• Still do not match catalyst lifetime• Separation problem when absorbent and catalyst are mixed
Natural calcium-based sorbents: calcite and dolomite• Good availability and low cost• Large absorption capacity and satisfactory reaction kinetics• Proven enhanced hydrogen yields up to 95+ vol%
Interest in developing novel synthetic Ca-based sorbents
1) Nano-CaO particles (precipitated calcium carbonate PCC)higher reactivity and high conversion rates
2) Use of a inert binder to limit the sintering of the CaO and improve the durability of the sorbent: Mayenite Ca12 Al14 O33
09.11.2010
Development of Ca-based sorbentsSynthesis of Ca3 Al2 O6 micropowder / Characterization
Characterization techniques:X-ray Diffraction for phase analysisScanning Electron MicroscopyElemental Analysis for composition of the material Thermo-gravimetrical analysis (TGA) for sorption studiesFixed bed reactor for SE-SMR investigation
50 um
Ca 2+ solution Al 3+ solution
Polymerizingagent
Complexingagent
HT Calcination1000oC, 24h
”New synthesis method for CaO-based synthetic sorbents with enhanced properties for high-temperature CO2 -capture”Mastin J., Aranda A., Meyer J. Energy Procedia (2010)
09.11.2010
Development of Ca-based sorbents
Thermaltreatment
CaCO3
Homogeneous particles Decomposition of aluminate / Migration on the surface/ Carbonation
Ca3 Al2 O6CaO /
Ca12 Al14 O33
Thermaltreatment
CaOCO2
Ca12 Al14 O33Ca12 Al14 O33
• Ca12 Al14 O33 : inert and stable under operative conditions• “Free” CaO reacting with CO2• Theoretical max absorption capacity: 20,98g (CO2 ) / 100g (Ca3 Al2 O6 )
09.11.2010
Development of Ca-based sorbentsLong-term durability of mixed CaO/Ca3 Al2 O6 powders
Optimal composition: 20wt% CaO – 80wt%Ca3 Al2 O6
Total absorption capacity: 29g(CO2 )/100g sorbent
09.11.2010
Development of Ca-based sorbentsLong-term durability of mixed CaO/Ca3 Al2 O6 powders
No loss of reactivity during long-term multi-cyclingStable in severe calcination conditions (Regeneration at 925oC, 85% CO2, 15% H2 O)
09.11.2010
Synthetic sorbent Vs Natural sorbent
Calcite: CaODolomite: 58.2wt% CaO / 41.8wt% MgOIFE’s sorbent (after thermal treatment): 45wt% CaO / 55 wt% Ca12 Al14 O33
09.11.2010
Mechanical Properties
Porous / Inert ceramic matrix Small particles of CaO homogeneously distributed Limited sintering High reactivity Mechanical Strength Specific surface (7m2/g)
Calcined Powder Compaction Thermal treatment
Innovative method for production of sorbent particles
09.11.2010
Mechanical Properties of sorbent particles
Calcite Dolomite Synthetic sorbent
Raw particle 17,47 (4.2) 11,2 (2,8)
22,7 (9,7)After calcination (900oC 6h)
11,6 (2,6) 5,86 (2,5)
After 200 cycles
(sintered)17,06 (4,3) 15,97 (3,7) 24 (3,3)
Development of efficient agglomeration techniques are required for large-scale production of sorbent particles !
Correlation particle strength – resistance to attrition evidenced
Improved strength compared to natural sorbents (30-40%)
Stable strength during cycling
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H2 -production by SE-SMR process
Typical SE-SMR curve – Fixed bed experiment
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H2 -production by SE-SMR processFixed bed Experiments
Decrease of the H2 production timeDivided by a factor 3 after 25 runs
Stable production timeevidenced for 66 runs so far…
Dolomite Synthetic sorbent
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“All-in-one” particle• Inert support / CO2 sorbent / reforming catalyst integrated in one single
particle• Avantages: - Cost reduction
- Better interaction catalyst/sorbent- No separation problems- Homogeneous reactor bed (fixed bed or fluidized bed)
Catalyst layer on the outer surface
SorbentH2 CO2
CH4 Catalyst
Support
CaOH2 O
Challenges: - Oxidation/sintering of the catalyst during regeneration- Long term activity of the catalyst- Chemical stability / Poisoning- Interaction support/catalyst
09.11.2010
Summary of properties of the novel sorbent
• Elevated CO2 absorption capacity (20-30g CO2 /100g sorbent)• Good reaction kinetics at SE-SMR temperature and CO2 partial
pressure• Long-term stability during carbonation-calcination cycles• High chemical stability (inert and stable)• Improved mechanical stability compared to conventional
natural sorbent• Possibility to accommodate a catalyst in the structure
• Cost??? => minerals as starting raw precursors
09.11.2010
Future Test in demo-plant – HyNor ProjectNorwegian project for the introduction of H2 as fuel for transportation.Installation of a hydrogen-motorway in the south of Norway with various H2 stations
HyNOR-Lillestrøm/Akershus Energy/IFEInstallation of a demo-plant for H2 production via SE-SMR (10Nm3/h) in 2011
www.hynor.no
