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11/05/2009
1
Dense Dense CeramicCeramic Membrane Membrane forforEnergy Energy TechnologyTechnology
UniversityUniversity of Salentoof Salento
Department Engineering of InnovationDepartment Engineering of Innovation
Authors: Anastasia Rocca; Antonio Authors: Anastasia Rocca; Antonio LicciulliLicciulli; Daniela ; Daniela DisoDiso; ; MoniaMonia PolitiPoliti
� ENEA UTS MAT, Brindisi, Italy
� Doctor Marco Alvisi
� Research Centre ENEL-Cerano, Brindisi, Italy
� Doctor Monia Politi
� Department of Materials Science and Engineering, NTNU Trondheim, Norway
� Professor Mari-Ann Einarsrud
� Salentec SRL, Cavallino (Lecce), Italy
� Doctor Daniela Diso, Eng. Antonio Chiechi
CollaboratorsCollaborators
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� Applications of ceramic materials in energy technology
� Activities of research
� Asymmetric ceramic membrane
� Dense ceramic membrane
� Conclusion
Outline of presentation
Ceramic material for energy technology
Related to present large oil, gas and coal resources and future use of hydrogen technology
� Dense ceramic oxygen/hydrogen permeable membranes
� Natural gas conversion into liquid energy carriers and chemicals (GTL)
� Power generation with CO2 capture
� clean coal technologies
� H2 technology
� Production of pure gasesEnergy resources used
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� GTL technologies commercially available for syngas production:
� Steam reforming (SR)
� Partial oxidation (POX)
� Autothermal reforming (ATR)
� Syngas is the starting point for a wide range of chemicals and fuels bring natural gas to marked
� Advantages
� No Nox emission
� Low CO2 emission
GTL (gas to liquid) technologies
Clean coal technologies
� Development of protonconducting membranes, forhydrogen separation fromgas mixtures (syngas), deriving from the gasification of coal.
The membranes must:
� operate at high temperature (600-900°C)
� be stable in CO2-containing environments
� achieve optimal thermostructuralproperties
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The amount of protonic charge transported depends:
� dopant concentration� number of oxygen vacancies� ambient conditions� temperature
Perovskite proton membranes for hydrogen separation
The driving-force of proton and electron conductivity throughthe membrane is the carrier concentration gradient.
The perovskites are oxides with structure of ABO3-type.
GENERATION OF PROTON CARRIERS INTO THE PEROVSKITE CERAMIC
•+⇒+ ixoO HOVOH 2..
2
Integrated design for gas separation
� Preparation of syngas from natural gas by oxygen permeable membrane
� Extraction of hydrogen from syngas by proton permeable membrane (N2 gas used as sweep gas on H2 rich side)
� Extraction of CO2 for deposition
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CO2 pre-combustion capturing
� Increased conversion of equilibrium limited reactions
� Separate hydrogen and CO2 streams
� No traditional CO2 removal system required
� 100% CO2 capture
� 30 – 50% CO2 capture cost reduction, compared to conventional amine scrubbing
� Asymmetric ceramic membrane
� La0.995Sr0.005NbO4
� Powder synthesis
� Spray pyrolysis
� Porous substrate
� Tape casting
� Dense thin film
� Air brush technique
Activities of research
� Dense ceramic membrane
� SrTi0.995Tm0.005O3
� Powder synthesis
� Sol-gel method
� Membrane forming
� Dry pressing
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Asymmetric membrane:powder synthesisThe solution is atomized through a nozzle and is sprayed into a hot furnace (800 °C)
Water evaporates oxide is formed
SPRAY PYROLYSIS
RAW POWDERCALCINATION
800°C
LSN POWDER
Asymmetric membrane:porous substrate
LSN+ carbon pore filler + PVA
TAPE CASTING
LAMINATION
BURNING ORGANIC OFF
SINTERIZATION 1250°C
A method to obtain an 1.5 meter ceramic film and 10 cm width. Thickness can be set through two micrometers positioned on Dr.Blade.
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Asymmetric membrane
� A thin dense layer was successful deposited on porous substrate by means of an optimized spray technique (inexpensive process).
� Thin dense layer (39 µm) is fine sinterized, continuous and cracks free.
� Carbon black give good porous substrates: pores of optimal dimension (1÷20 µm) and porosity above 26%.
Further work could be tape casted film mechanical properties investigation on LSN+carbonstructure.
Dense ceramic membrane: forming, sintering and machining
GELDRYING AT
80°C
POWDERS CALCINATION
AT 1100°C
MILLING
DRY PRESSINGSINTERIZATION
1350°C
LAVORATION CNC
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X-ray Diffraction (XRD)
XRD at ambient temperature onsinterized samples at differenttemperature
� The diffraction spectrum of the calcined powders shows the presence of perovskite phase of titanate strontium at 1100°C.
� Among 1100 and 1350 peaks are narrower higher.
� At 1500°C new crystalline phases form.
Mechanical characterization
SAMPLES TYPE
dev.st[MPa]
E [GPa]
STO _Tm(on powders)
121.7 ±17.0 42.7
STO_Tm SAFFIL
145.6 ±21.7 45.6
][MPamediaσ
� The sinterized samples on SAFFIL alumina fibers are more resistant that those sinterized on powders.
� The best strength is due to thermic insulation of the sample by fibers.
� Mechanical characterization of membranes were performed by 3-pointflexure test(ASTM C1161)
� The samples for mechanical test are obtaneid from thin plates, formedby pressing and sinterized at 1350°C.
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50 µm
10 µm
STO_Tm0.5%mol
Dense ceramic membrane
The innovative membrane SrTi0.995Tm0.005O3 is optimized in terms of:
� Residual porosity (only 2%)
� Crystalline composition
� Mechanical resistance (≈ 150 MPa)
� Mechanical and vacuum seal
An extensive test program has been undertaken to fully characterize proton conduction properties .
Many challenging scientific and technological problems to be solved to promote application of functional oxide ceramic materials in energy technology.
� Material stability and compatibility
� Strength and reliability
� Flux at process conditions
� Fabrication
� Sealing and manifolding
Our future focus will mainly be on proton conductors.
Conclusion
Air
N2
Pt
Membrane