STUDY OF CuO-BASED MATERIALS FOR Ca/Cu REFORMING PROCESS

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1 STUDY OF CuO-BASED MATERIALS FOR Ca/Cu REFORMING PROCESS 6 T H H I G H T E M P E R AT U R E S O L I D L O O P I N G C Y C L E S P o l i t e c n i c o di M i l a n o, M i l a n, I t a l y 1 s t 2 n d S e p t e m b e r L. Díez [ 1 ], G. G r a s a [ 1 ], R. M u r i l l o [ 1 ], A. S c u l l a r d [ 2 ] G. W i l l i a m s [ 2 ] [1] I n s t i t u t o d e C a r b o q u í m i c a ( I C B - C S I C ), Z a r a g o z a / S p a i n [2] J o h n s o n M a t t h e y P u b l i c L i m i t e d C o m p a n y, L o n d o n / U n i t e d K i n g d o m l d i e z m a r t i i c b. c s i c. e s, g g i c b. c s i c. e s, r m u r i l l c s i c. e s T h i s w o r k h a s b e e n f u n d e d b y t h e f o l l o w i n g p r o j e c t s : A S C E N T E U 7 t h F P 7, N º : C I C A C U H S p a n i s h G o v e r n m e n t - E N E C O 2-1

2 INDEX PROCESS DESCRIPTION OBJECTIVES SYNTHESIS ROUTES EXPERIMENTAL AND CHARACTERIZATION CuO-BASED POWDER MATERIALS RESULTS PELLETS RESULTS CONCLUSIONS

3 PROCESS DESCRIPTION: Ca/Cu REFORMING Novel system to produce H 2 with inherent CO 2 capture with Ca/Cu chemical loop CH 4 (g) + CaO(s) + 2H 2 O CaCO 3 (s) + 4H 2 (g) H 298K = kj/mol CALCINATION Ca chemical loop to capture CO 2 by carbonation CaCO 3 (s) CaO (s) + CO 2 (g) ) H 298K = kj/mol Highly endothermic reaction Cu chemical loop to provide the heat necessary for calcination reaction by CuO reduction CuO(s) + H 2 (g) Cu(s) + 2H 2 O(g) CuO(s) + CO(g) Cu(s) + CO 2 (g) 4CuO(s) + CH 4 (g) 4 Cu(s) + CO 2 (g) + 2H 2 O(g) H 298K = kj/mol H 298K = kj/mol H 298K = kj/mol

4 PROCESS DESCRIPTION: STAGES OF THE PROCESS A) Generating of a H 2- rich stream by reforming of CH 4 with H 2 O steam, and simultaneous carbonation of CaO with CO 2 generated (T=65ºC, P=2bar). B) Oxidation of Cu to CuO in air atmosphere. CuO will be employed in the calcination step (T=83ºC, P=2bar). C) Calcination of CaCO 3 and reduction of CuO using an additional fuel source. By reduction of CuO the heat needed for calcination reaction has to be achieved (T=87ºC, P=1bar).

5 PROCESS DESCRIPTION: MATERIAL REQUIREMENTS CaO-based sorbent approximately 3%wt. CaO to capture CO 2 Cu-based material Cu contents between 5 7%wt. to provide energy for calcination. Reforming catalyst to fulfill the reforming reaction. Suitable proportions of Ca/Cu to ensure that reactions take place in the right reaction stages. Fixed bed reactors the process requires that materials be pelletized

6 PROCESS DESCRIPTION: CuO MATERIAL Needed to supply the energy requirements (regeneration of sorbent) for the Ca/Cu process by CuO reduction. CuO-based materials present favorable features such as: High oxygen transport capacity Chemical and mechanical stability in repeated cycles of red/ox High reaction rates in red/ox stages Low environmental impact No expensive Several studies has focused on use Al 2 O 3 as a support good chemical and mechanical behavior, availability and low cost but Al 2 O 3 can interact with CuO forming CuAl 2 O 4. Other alternative promising supports could be: MgAl 2 O 4, ZrO 2, TiO 2, SiO 2 Need to probe CuO-based materials supported on different materials, synthesized by several routes, varying Cu contents.

7 OBJETIVES: ANALYSIS OF CuO-BASED MATERIALS CuO-based materials in powder form Cu contents between 5%wt. to 75%wt Several synthesis routes Co-precipitation Spray-drying Deposition-precipitation Mechanical mixing Supports: Al 2 O 3, MgAl 2 O 4 and ZrO 2 Pellets based on CuO prepared by compression Co-precipitation: Al 2 O 3 and MgAl 2 O 4

8 SYNTHESIS ROUTES SPRAY DRYING CO-PRECIPITATION Boehmite slurried in water Calcination Analysis of samples Cu nitrate & Al Nitrate solutions mixed Calcination Analysis of samples Cu nitrate dissolved in water and added to boehmite slurry Spray Dried product collected Na2CO3 slowly fed to water, controlling Ph Drying Spray Drying parameters set Slurry fed to spray dryer Aging of solution Filtration and Washing DEPOSITION-PRECIPITATION Cu nitrate solution heated Calcination Analysis of samples MECHANICAL MIXING Copper oxide Alumina Analysis of samples Alumina is slurried in water and heated adjusting ph with Na2CO3 Drying Mixing of solids Hot nitrate solution fed to the ph and T controlled alumina slurry to precipitate Filtration and Washing Calcination

9 EXPERIMENTAL AND CHARACTERIZATION CHEMICAL AND MECHANICAL STABILITY TESTS IN THERMO GRAVIMETRIC ANALYZER (TGA) Powder : TGA tests via 1 red/ox cycles at 87ºC. Pellets: TGA tests via 2 red/ox cycles at 87ºC. TESTS: Reduction: 2% H 2 in N 2 at 87ºC Oxidation: 2% O 2 in N 2 at 87 ºC 1 min purge in N2 between stages CHARACTERIZATION - X-Ray Diffractometry Analysis (XRD) to identify crystalline species - Temperature-programmed reduction test (TPR) to determine reducible species - He picnometry to calculate solid density - Physorption (BET method) to calculate specific surface area

10 CuO-based MATERIALS IN POWDER Reference Support Synthesis method %Cu in oxid samples Origin AE1786* Al 2 O 3 Spray-drying 75. JM AE1787A Al 2 O 3 Co-precipitation 65.5 JM AE1787B Al 2 O 3 Co-precipitation 63. JM AE1787C Al 2 O 3 Co-precipitation 62. JM AE1788A Al 2 O 3 Deposition-precipitation 64.4 JM AE1788B* Al 2 O 3 Deposition-precipitation 62.5 JM AE1788C* Al 2 O 3 Deposition-precipitation 62.5 JM AE1788D* Al 2 O 3 Deposition-precipitation 56.3 JM CuAl A1 Al 2 O 3 Mechanical mixing 63.6 JM CuAl A2 Al 2 O 3 Mechanical mixing 59.6 JM CuAl B1 Al 2 O 3 Mechanical mixing 63.7 JM CuAl B2 Al 2 O 3 Mechanical mixing 6.4 JM CuAl C1 Al 2 O 3 Mechanical mixing 63.1 JM CuAl C2 Al 2 O 3 Mechanical mixing 62.3 JM CuAl D1 Al 2 O 3 Mechanical mixing 63.4 JM CuAl D2 Al 2 O 3 Mechanical mixing 62.1 JM Cu 1.1 MgAl 2 O 4 MgAl 2 O 4 Co-precipitation 49. ICB CSIC Cu 3.1 MgAl 2 O 4 MgAl 2 O 4 Co-precipitation 59.7 ICB CSIC Cu 4.2 MgAl 2 O 4 MgAl 2 O 4 Co-precipitation 63.1 ICB CSIC Cu 5.2 MgAl 2 O 4 MgAl 2 O 4 Co-precipitation 69. ICB CSIC Cu 1.2 ZrO 2 ZrO 2 Co-precipitation 48.1 ICB CSIC Cu 4.2 ZrO 2 * ZrO 2 Co-precipitation 67.3 ICB - CSIC *: sample agglomerated

11 RESULTS: POWDER MATERIALS Characterisation: XRD, TPR, He picnometry, BET surface - XRD tests: CuO/Al 2 O 3 Example of XRD fresh and oxidized cycled for AE1787B (co-precipitation) XRD test revealed the presence of CuAl 2 O 4 Only some materials prepared by mechanical mixing did not present CuAl 2 O 4 CuO/MgAl 2 O 4 and CuO/ZrO 2 No intermediate species are detected Cu 4.2 MgAl 2 O 4 Cu 1.2 ZrO 2 CuO MgAl2O4 CuO ZrO2 fresh fresh cycled cycled q q

12 RESULTS: POWDER MATERIALS Characterization: XRD, TPR, He picnometry, BET surface - TPR tests of fresh materials: - CuO peak between 17 3 ºC - CuAl 2 O 4 peak between 35 4 ºC AE1786 prepared via spray-drying wide peak with two little bends (interaction with support or different forms of CuO present) AE1787A prepared by co-precipitation most defined peak AE1788C prepared by deposition-precipitation wide peak Samples synthesized by mechanical mixing and co-precipitation (Al 2 O 3, MgAl 2 O 4 and ZrO 2 ) showed defined CuO peaks. CuAl A1 fresh CuAl B2 fresh CuAl C2 fresh Cu 3.1 MgAl2O4 fresh Cu 4.2 MgAl2O4 fresh Cu 1.2 ZrO2 Cu 4.2 ZrO T (ºC) T (ºC) T (ºC)

13 Specific surface area (m2/g) Specific surface area (m2/g) RESULTS: POWDER MATERIALS Characterization: XRD, TPR, He picnometry, BET surface SPECIFIC SURFACE AREA CuO/Al 2 O 3 CuO/MgAl 2 O 4 and CuO/ZrO AE1786 AE1787A AE1787B AE1788A AE1788B AE1788C AE1788D Cu 3.1 Al2O3 Cu 4.1 Al2O3 Cu 1.1 Cu 3.1 Cu 4.2 Cu 5.2 MgAl2O4 MgAl2O4 MgAl2O4 MgAl2O4 Cu 1.2 ZrO2 Cu 4.2 ZrO2 Sb by spray-drying Sb for CuO/ZrO 2 materials The samples with the lowest value of Sb suffered agglomeration

14 mg O transported/mg oxidized solid X oxidation RESULTS: CuO/Al 2 O 3 POWDER MATERIALS CuO/Al 2 O 3 TGA: Oxidation-reduction cycles (87ºC, 2%v. O 2 /N 2 ; 2%v. H 2 /N 2, 1 min N 2 purgue) Chemical stability Oxidation conversion curves Some materials showed constant OTC, but degradation of the oxidation conversion curves and showed agglomeration AE1786 by spray-drying Cu =76%wt Cycle number Cycle 1 Cycle 2 Cycle 5 Cycle 8 Cycle Time (min) Some materials showed constant OTC, and repetitive oxidation curves, but presented important agglomeration: precipitationdeposition materials AE1788C

15 mg O transported/mg oxidized solid X oxidation mg O transported/mg oxidized solid X oxidation RESULTS: CuO/Al 2 O 3 POWDER MATERIALS Oxidation-reduction cycles (87ºC, 2%v. O 2 /N 2 ; 1%v. H 2 /N 2, 1 min N 2 purgue) Cycle number CuO/Al 2 O 3 Chemical stability Cycle number Oxidation conversion curves Cycle 1 Cycle 2 Cycle 5 Cycle Time (min) Cycle 1 Cycle 2 Cycle 5 Cycle Time (min) Co-precipitation: AE1787A, B,C,D AE1787B High chemical stability Fast kinetics Complete conversion High capacity of O 2 release No agglomeration Mechanical mixing: A1,2, B1,2, C1,2, D1,2 CuAl D2 Selected for pelletizing

16 mg transported/mg O oxidized solid X oxidation mg O transported/mg oxidized solid X oxidation RESULTS: CuO/ZrO 2 POWDER MATERIALS TGA: Oxidation/reduction cycles (87ºC, 2%v. O2/N2; 1%v. H 2 /N 2, 1 min N 2 purgue) Chemical stability Cycle number Cycle number Oxidation conversion curves Cycle 1 Cycle 2 Cycle 5 Cycle Time (min) Cycle 5 Cycle 1 Cycle 2 Cycle 5 Cycle 8 Cycle 1 Cycle Time (min) Cu 1.2 ZrO 2 Cu = 47%wt. Chemically stable but %Cu CuO/ZrO 2 materials, progressive loss in O 2 transport capacity and high agglomeration for the same values of Cu content Cu 4.2 ZrO 2 Cu = 67%wt.

17 mg O transported/mg oxidized solid X oxidation mg O transported/mg oxidized solid X oxidation RESULTS: CuO/MgAl 2 O 4 POWDER MATERIALS Chemical stability Oxidation conversion curves CuO/MgAl 2 O 4 materials Cycle number Cycle 1 Cycle 2 Cycle Time (min) Cu 4.2 MgAl 2 O 4 Cu = 63%wt. Highly stable oxygen transport capacity and repetitive reduction and oxidation curves without agglomeration Cu 5.2 MgAl 2 O 4 Cu = 7%wt Cycle number Cycle 1 Cycle 2 Cycle 5 Cycle 8 Cycle Time (min) High chemical stability, but there seems to be a small Cu aluminate formation.

CuO-based PELLETS Reference Origin Support Length (mm) Diameter (mm) Horizontal Crush Strength, HCS (kg) %Cu in oxidized samples S397/147/2 JM Al 2 O 3 3.

18 CuO-based PELLETS Reference Origin Support Length (mm) Diameter (mm) Horizontal Crush Strength, HCS (kg) %Cu in oxidized samples S397/147/2 JM Al 2 O Cu 4.2 MgAl 2 O 4 ICB-CSIC MgAl 2 O Cu 5.2 MgAl 2 O 4 ICB-CSIC MgAl 2 O Pressing properties: 35 kg/cm 2 during 24 hours

19 mg O transported/mg solid RESULTS: PELLETS TGA: Oxidation-reduction cycles (87ºC, 2%v. O 2 /N 2, 2%v. H 2 /N 2, 1 min N 2 purgue) Chemical stability of Pellets.2 Pellet Cu 4.2 MgAl 2 O 4 7 cycles 17 cycles Pellet Cu 4.2 MgAl2O4.4 Pellet Cu 5.2 MgAl2O4 Pellet S397/147/2 JM Pellet S397/147/ Cycle number Fresh 7 cycles 1 cycles

20 X reduction X oxidation X reduction X oxidation RESULTS: PELLETS Comparison of conversion curves for CuO/Al 2 O 3 and CuO/MgAl 2 O 4 pellets Cycle: Pellet Cu 4.2 MgAl2O4 Pellet Cu 5.2 MgAl2O Pellet Cu 4.2 MgAl2O4 Pellet Cu 5.2 MgAl2O4.2.1 Pellet S397/147/2 JM.2.1 Pellet S397/147/2 REDUCTION Time (min) Time (min) 1 OXIDATION.9.9 Cycle: Pellet Cu 4.2 MgAl2O4.5 Pellet Cu 4.2 MgAl2O4.4.3 Pellet Cu 5.2 MgAl2O4.4.3 Pellet Cu 5.2 MgAl2O4.2.1 Pellet S397/147/2 JM.2.1 Pellet S397/147/2 JM Time (min) Time (min)

21 CONCLUSIONS There seems to be a limit in Cu content in the material to prevent agglomeration, that might depend on the inert support as Cu 76%wt. in Al 2 O 3, Cu 69% wt. in MgAl 2 O 4 and 67% wt. in ZrO 2 resulted in non stable materials. There seems to be suitable powdered materials (either on to Al 2 O3 or MgAl 2 O 3 ) and Cu contents around 65 %wt. that present high chemical stability, fast reaction kinetics and did not agglomerated. The production of two of these materials will be scaled up to be tested in the Ca/Cu process: AE1787B Co-precipitation - JM Cu 4.2 MgAl2O4 Co-precipitation ICB Co-precipitation and mechanical mixing resulted in suitable synthesis routes. The most promising materials have been pelletized and tested. These pellets showed positive results to be applied maintaining chemical and mechanical stability after cycling.

22 AKNOWLEDGEMENTS Advance Solid Cycles with Efficient Novel Technologies ASCENT EU FP7, Nº: Hydrogen production with CO2 capture using novel Ca-Cu reforming cycles CiCaCuH Spanish Government, ENE CO2-1 Grupo de Investigaciones Medioambientales GIM Diputación General de Aragón, Research group funding

23 THANK YOU FOR YOUR ATTENTION! 6 T H H I G H T E M P E R AT U R E S O L I D L O O P I N G C Y C L E S P o l i t e c n i c o di M i l a n o, M i l a n, I t a l y 1 s t 2 n d S e p t e m b e r L. Díez [ 1 ], G. G r a s a [ 1 ], R. M u r i l l o [ 1 ], A. S c u l l a r d [ 2 ] G. W i l l i a m s [ 2 ] [1] I n s t i t u t o d e C a r b o q u í m i c a ( I C B - C S I C ), Z a r a g o z a / S p a i n [2] J o h n s o n M a t t h e y P u b l i c L i m i t e d C o m p a n y, L o n d o n / U n i t e d K i n g d o m l d i e z m a r t i i c b. c s i c. e s, g g i c b. c s i c. e s, r m u r i l l c s i c. e s T h i s w o r k h a s b e e n f u n d e d b y t h e f o l l o w i n g p r o j e c t s : A S C E N T E U 7 t h F P 7, N º : C I C A C U H S p a n i s h G o v e r n m e n t - E N E C O 2-1

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