ydrogen Storage and Delivery in a Liquid Carrier Infrastructure Guido P. Pez, Alan C. Cooper, ansong Cheng, Bernard A. Toseland and Karen Campbell Corporate Science and Technology Center, Air Products and Chemicals, Inc., Allentown, PA 18195
Air Products ydrogen Experience World leader in industrial hydrogen supply Own, operate, and distribute hydrogen Americas, Europe, Asia Operate over 60 plants, 7 pipelines, produce over 1.25 million tons/year Demonstration leader in hydrogen fueling infrastructure 30 fueling stations - Americas, Europe, Asia Technology advances include mobile fueling, underground liquid storage, dispensing, onsite generation, storage Global safety leader 3
ydrogen Storage Methods Physical methods compression (350, 700 bar) liquid hydrogen (20 K) Physical adsorption (- bond remains intact) adsorption on high surface area materials activated carbon, carbon nanotubes, zeolites Chemisorption (- bond broken) metal hydrides (LaNi 5, FeTi) advanced hydrides (NaAl 4 ) chemical hydrides - hydrolysis (NaB 4 ), benzene +3 2 cyclohexane ydrogen storage is one of the key technical barriers to the use of hydrogen as an energy carrier 4
An Integrated Production, Storage and Delivery of ydrogen Using Reversible Liquid Carriers (LQ* 2 ) 2-Way liquid transport LQ* 2 At a 2 Source Site: cat. 2 + LQ* LQ* 2 using existing liquid fuels infrastructure Station LQ* LQ* 2 Dehydrogenation 2 LQ* On Board hydrogen storage, delivery 2 (P) cat. Carrier Liquid (LQ*) Source LQ* 2 LQ*+ 2 On Site 2 delivery 5
Approach: An off-board regenerable liquid carrier for vehicles and stationary 2 gas delivery LQ* 2 LQ = liquid carrier = heat Liquid Storage Tank LQ Catalytic Converter eat Exchange Fuel Cell 2 Conformable shape liquid tank with design to separate liquids; 22.5 gallons for 5 kg hydrogen at 6 wt. % and unit density eat exchange reduces the vehicles radiator load by ca. 40% (for of 12 kcal/mol 2 and 50% FC efficiency) LQ* 2 + heat ( ) Catalyst P < 10 atm. P > 50 atm. Catalyst LQ + 2 Maximum energy efficiency: by (a) recovering the exothermic (- ) of hydrogenation and (b) utilizing the waste heat from the power source to supply the for the endothermic dehydrogenation. 6
Partial List of Organic Liquid Carrier Performance Criteria Benzene (gas) + 3 2 ydrogenation Catalyst Dehydrogenation of >350 ºC exp.: -16.4 Kcal/mol 2 Cyclohexane (gas) Optimal heat of dehydrogenation (Δ = 10-13 kcal/mole 2 ), enabling the catalytic dehydrogenation in an all-liquid state at temperatures (<200 o C) for utilizing the FC s or ICE s waste heat. Meet DOE s hydrogen on board storage and delivery targets Low volatility (b.p. > 300 o C), enabling the dehydrogenation in small compact reactor systems onboard vehicles and reducing exposure to vapors Low toxicity and environmental impact Clean catalytic hydrogenation and dehydrogenation, enabling multiple cycles of use with no significant degradation of the molecule Manufacture of the liquid carriers from low cost, source raw materials. 7
Prior Art on Organic Liquid Carriers ydrogen and energy storage 1 by a reversible catalytic hydrogenation of naphthalene C 10 8 to decalin C 10 18 (a liquid organic hydride 2 ) +5 2-5 2 o =-15.1 kcal/mole 2 igh conversion of C 10 18 in membrane reactor at ~320 o C 2 Efficient 2 evolution from C 10 18 from 195 o C to 400 o C under wet-dry multiphase 3 or superheated liquid film conditions 4-5. (Both are two-phase liquid/vapor processes.) Condenser for C 10 8 2 Catalyst (Temp >b.p.) eater 8 1. E. Newson Int,. J. ydrogen Energy, 23 905 (1998) 2. R. O. Loufty et al, Proc. Of Int. 2 Energy Forum, 3. N. Kariya, M. Ichikawa et al, Appl. Cat A, 233, (2002), 91-102 (2000) 335-340 5. S. odoshima and Y. Saito, Int. J. y Energy, 28, (2003), 197-204 4. S. odoshima et al, Suiso Enerugi Shisutemu 25, (2000), 36-43
Fundamental Energetics for Containing ydrogen K For 2 (gas) + carrier 2 (contained) equilibrium: G = - T S = RTlnK For containing hydrogen in a spontaneous prcess: a) For carrier bound, but intact molecular 2 (physisorption) (-Δ) <~8 kcal mole 2 (-ΔS) <~25 e.u. b) For carrier bound dissociated 2 (chemisorption) (-Δ) >~8 kcal/mole 2 (-ΔS) ~25-30 e.u. and ~30 e.u. for 2 +aromatics alkanes The greater variable contribution to ΔG is fromδ 9
Observed and Desirable 2 -Containment Enthalpies (-, kcal/mole 2 ) 0 Liquid Carrier 20 1 2 5 7 7.3 8.8 9.8 11.1 13 15 17.7 18.7 graphite/ 2 77K SW carbon nanotubes 4 C 24 K 5 LaNi 5 1 (1.8 atm, 25 C) NaAl 4 diss.2 TiFe 0.8 Ni 0.2 0.7 (0.1 atm 25 C) Desired (- ) ranges : 5-7 kcal/mole 2 -Strong Physisorption : 7-13 kcal/mole 2 Weak to Moderate Chemisorption : 10-13 kcal/mole 2 optimal for liquid carrier Note: Lower eating Value for 2 (LV) = 57 kcal/mole Na 3 Al 6 diss. 2 (5.6 wt% total) 1. G. Sandrock, J. of Alloys and Compounds 293-295 (1999) 877 2. B. Bogdanovic, G. Sandrock, MRS Bulletin 2002, 712 3. W. Peschka, Liquid ydrogen Fuel of the Future Springer-Verlag p. 65 4. M. aas et al., J. of Materials Research 20 (12) 3214 (2005) 5. K. Watanabe et al., Proc. R. Soc. London A333, 51 (1973) Napthalene (C 10 8 ) decalin (C 10 18 ) ~7.4 wt% Mg 2 1 atm ~290 C ~7.5 wt% 2 liquefaction work 3
Enthalpies of ydrogenation as Function of N Substitution Desirable Fused Multi-Ring Aromatics and Inclusion of N-eteroatoms can greatly lower US and non-us patents pending
ydrogenation/dehydrogenation of N-Ethylcarbazole 6 2 Ru / Al 2 O 3 130-170 o C 1000 psi 2 100 % calc.= -12.4Kcal/mole 2 esc. = -12.2Kcal/mole 2 Capacity : 5.8 % N 2 C C3 Pd / C 200 o C 3 C N C 2 6 2 US and non-us patents pending
Flow Measurement of ydrogen Generation from N-ethylcarbazole (Ramp from 25 o C to 200 o C, 1 atm. 2,, 40:1 substrate/catalyst) 2 Temperature ( o C) desorbed (wt. %) GC/MS analysis after run termination showed loss of 5.7% wt. 2 13
Cycling Studies Dehydrogenation: Ramp from 25 o C to 200 o C, 15 psia 2 ydrogenation: 170 o C, 1200 psia 2 N-ethylcarbazole C 3 N Cycle 1 Cycle 2 Cycle 3 Rapid hydrogenation and cycling stability 14
Understanding the Mechanism - 2 2-2 2-2 2 N + 2 2 N + 2 2 N + 2 2 N (11.3)* (12.4)* (12.8)* ( )* : calc. (B3LYP/G-311G**) in Kcal/mol 2 exp. (overall) = 12.2 kcal/mole 2 15
N-ethylcarbazole Dehydrogenation: (Ramp from 25 o C to 150 o C, 15 psia 2 ) Slow catalytic dehydrogenation rate at 150 o C 16
Dehydrogenation Flow Reactor Test System 2 Packed Bed Reactor 17
Packed Bed Reactor Dehydrogenation/ ydrogenation Cycling Demonstration 190 o C; 0.25 ml./min/ Liquid Flow 18
2 Purity from Continuous Flow Dehydrogenation Experiments Component ydrogen Methane Ethane Carbon Monoxide N containing compounds C3 s C4 s C5 s C6 s Mole % 99.9+ 0.0013% 0.0083% ND ND ND ND ND ND ND Non Detectable 19
Illustration of Conformers: Decalin Naphthalene E N T A L P Y (kcal/mole) o cis = -76.40 o trans = -79.59 cis-decalin 0 trans-decalin -3.19 20
Perhydro-Nethylcarbazole Conformers At B3LYP/G-311G** level E = 0 21 E = 2.6 kcal/mol E = 8.6 kcal/mol E = 14.5 kcal/mol
Flow Measurement of ydrogen Generation from N-ethylcarbazole: Kinetic versus Thermodynamic Conformers 20% metastable conformers from 170 o C hydrogenation 80% metastable conformers - from 120 o C hydrogenation US and non-us patents pending
Increasing Capacity: ydrogen Generation from Phenylenecarbazole GC/MS analysis after run termination showed loss of 6.2 % wt 2 23 Theory is 6.9% wt 2
No Perfect World! N Dehydrogenation N + N 80% 20% Presence of secondary amine confirmed by alkylation and by GC/MS Second fused five-membered rings can cause strain. 24
Phenanthrolene Dehydrogenation N N Theoretical: 7.2% wt. % 2 and 69 g 2 /L 25 We have demonstrated a 7+ wt. % reversible capacity with this new carrier a 1.5 wt. % increase over N-ethylcarbazole
Oxygen-containing Carrier O Theoretical: 6.7% wt. % 2 and 69 g 2 /L 26 A member of a new class of hydrogen carriers containing only oxygen heteroatoms
Summary and Conclusions Liquid carrier concept provides an integrated hydrogen production, delivery and on-board storage scenario. Maximize use of existing liquids infrastructure Safety Energy efficiency Continuing material challenges: Optimal liquid carrier: 9 wt% for system (DOE s 2015 target) Optimal dehydrogenation catalysts for a compact, on-board liquid carrier 2 gas conversion reactor 27
Acknowledgements Atteye. Abdourazak Donald Fowler Aaron R. Scott Sergei Ivanov DOE ydrogen and Fuel Cells Program 28
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