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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..

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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