CERAMIC MEMBRANES IN ENERGY AND ENVIRONMENT RELATED APPLICATIONS

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1 Center for Research and Technology-Hellas Chemical Process Engineering Research Institute Laboratory of Inorganic Materials CERAMIC MEMBRANES IN ENERGY AND ENVIRONMENT RELATED APPLICATIONS Research at the Center of Research and Technology-Hellas V.T. Zaspalis

2 CONTENTS What is a membrane Separation of gas mixtures Low Temperature Applications: Water treatment Hydrogen from renewable sources High Temperature Applications: CONCLUSIONS Environmental friendly combustion of natural gas

3 What is a membrane A ceramic membrane is a thin semi-permeable film made of inorganic oxidic materials It can be porous so that selective transport takes place though the pores and through various mechanisms It can be non porous so that selective transport takes place through crystalline lattice diffusion It can be self-supported when is thick and strong enough, or supported on substrates when is thin and mechanically weak porous systems research goals Flux through dense systems selectivity of permeating substances

4 nanoporous layer What is a membrane 34cm 8mm 14mm mesoporous bridge layers macroporous substrate

5 What is a membrane Ceramic membranes at CERTH are prepared: Step 1: Synthesis of stabilized nanoparticle dispersions by metal-alkoxide hydrolysis Step 2: Membrane layer formation by dip-coating on porous substrates Step 3: Eventual further pore surface modification or size reduction by wet impregnation or vapor deposition techniques

6 Porous membranes, Separation of gas mixtures Scientific principle I: Knudsen law F K = AD K dc dx = A2εμ r k 3RT m v m ΔP L 8RT v m = π M In simple words: At nanopore level small molecules move faster than large ones This principle can form the basis for the development of separation techniques where mixtures of light (e.g. hydrogen) and heavy (e.g. hydrocarbons) components can be enriched in the light components

7 Porous membranes, Separation of gas mixtures Διαπερατότητα F (mol s-1 m-1 Pa-1) 5.E-08 5.E-08 4.E-08 4.E-08 3.E-08 3.E-08 2.E-08 2.E-08 1.E-08 5.E-09 Hydrogen Helium Nitrogen 0.E+00 0.E+00 1.E+05 2.E+05 3.E+05 4.E+05 Μέση πίεση συστήματος (Pa) 5.E+05 Hydrogen Propane Mixture 50/50 Hydrogen Propane Mixture 82/18 Membrane

8 Porous membranes, Separation of gas mixtures Scientific principle II: Kelvin law ρrt P 2σ cosϑ t ln = M P r 0 Vapor pressure of liquid concave in a pore is lower than that of the same liquid on a flat surface, it therefore condenses much earlier This principle can form the basis for the development of separation techniques on mixtures containing a condensable and noncondensable and non-soluble component

9 Porous membranes, Separation of gas mixtures Propane C 3 H 8 Separation factor 8 7,5 7 6,5 6 5, permeability x mol/m/s/pa Propylene C 3 H 6 Similar molecules very difficult to separate Temperature ( o C) C 3 H 6 : 50 C 3 H 8 : 50 C 3 H 8 : 12 C 3 H 6 : 88 H 2 : 50 C 3 H 8 : 50 H 2 : 2 C 3 H 8 : 98

10 Porous membranes, Separation of gas mixtures Scientific principle III : Activated microporous diffusion The pore is reduced down to the molecular dimensions and separation occurs by sieving Vapor deposition techniques H 2 : 50 CO 2 : 50 H 2 : 98.8 CO 2 : 1.2

11 Porous membranes, Water treatment 3 layers Σύστημα τριών στοιβάδων 4 layers 5 layers Σύστημα τεσσάρων στοιβάδων Σύστημα πέντε στοιβάδων Pure Water Νερό 6 Μονοσθενή Ιόντα Monovalent ions Πολυσθενή Ιόντα Multivalent ions Viruses Ιοί Bacteria Βακτήρια Αιωρούμενα Στερεά Suspended solids Μικροδιήθηση Υπερδιήθηση Νανοδιήθηση Αντίστροφη Όσμωση 1 0 0,1 0,01 0,001 0,0001 Μέσο μέγεθος σωματιδίων d p (μm) 4 t h 3 rd 2 nd 1 st

12 Porous membranes, Water treatment Removal of toxic metals (As, Cr) from water 1 ln = Qe Q K ad t lnq c Purified water product As: 1ppm Fe 2 O 3 nanoparticles ln(1/(qe-q)) Contact time, min 1 Fe: 2000 ppm Fe: 0,001 ppm As ion concentration (ppm) 0,1 Current maximum allowable limit 50ppb 0,01 feed product 5nm 2

13 Dense Membranes, Hydrogen from renewable sources One of the most promising and long-term sustainable routes for the production of energy is: H 2 O H Ο 2 The process currently under intensive research is the socalled RedOx process hydrogen production Τ 0 Τ 1 Τ 2

14 Dense Membranes, Hydrogen from renewable sources Our research-proposal is based on a dense oxygen conducting membrane reactor H 2 O. compartment 1 2o 2 V o, e O o compartment oevo. o 2 Membrane H 2 Mixed Conductor O 2

15 Dense Membranes, Hydrogen from renewable sources Hydrogen in compartment 1, T=900 o C, P 1 =P 2 =1bar 3.0E-08 CO off Time (hr) H 2 Ion Current (A) 2.5E E E E-08 Inactive state CO+H 2 O CO 2 +H 2 steady state: (~39 mmol H 2 m -2 hr -1 ) H 2 O 1/2O 2 +H 2 steady state (~13 mmol H 2 m -2 hr -1 ) 5.0E E+00 baseline (0 mmol H 2 m -2 hr -1 ) CO in (compartment 2) (activation) Time (s)

16 Dense Membranes, Environmental friendly combustion of natural gas AirH 2 O Methane (CH 4 ). compartment 1 2o 2 V o, e O o compartment oevo. o 2 Membrane H 2 Mixed Conductor O 2 CH 4 +2O 2 CO 2 +2H 2 O + Energy pure CO 2 STORAGE

17 Dense Membranes, Environmental friendly combustion of natural gas Material: La 0.7 Sr 0.3 Cu 0.05 Fe 0.95 O T=980 o C Air delivers oxygen CH 4 picks up oxygen Reactor loop number Oxygen available in the solid for reaction

18 CONCLUSIVE REMARKS Porous ceramic membranes (specially modified to the nanoporous region) can give high separation factors and give rise to the development of efficient process, in particular for the separation of hydrogen Porous ceramic membranes can provide technological solutions to many water treatment case-problems. The technology is quite mature to leave the laboratories Dense oxygen conducting membranes can give rise to the development of green high temperature processes towards either hydrogen production from renewable sources or CO 2 -capture oriented combustion of natural gas

19 ACKNOWLEDGEMENTS L. Nalbandian Research staff of the Laboratory of Inorganic Materials S. Sklari A. Evdou A. Pagana Technical staff of CERTH: T. Tsilipiras N. Georgiou A. Moudiotis The vapor deposition modifications of the membranes are being done in cooperation with: Prof. G. Sakellaropoulos, dr. S. Kaldis and S. Koutsonikolas of the department of Chemical Engineering of the Aristotle University of Thessaloniki

F321 MOLES. Example If 1 atom has a mass of 1.241 x 10-23 g 1 mole of atoms will have a mass of 1.241 x 10-23 g x 6.02 x 10 23 = 7.

F321 MOLES. Example If 1 atom has a mass of 1.241 x 10-23 g 1 mole of atoms will have a mass of 1.241 x 10-23 g x 6.02 x 10 23 = 7. Moles 1 MOLES The mole the standard unit of amount of a substance (mol) the number of particles in a mole is known as Avogadro s constant (N A ) Avogadro s constant has a value of 6.02 x 10 23 mol -1.