advanced gas sorption analysis system manual version · van’t hoff plot c h2 [h/m] p eq [bar]...
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Technologies
Advanced Gas Sorption Analysis SystemManual Version
www.grz-technologies.com
AGAS Mano
0 0.5 1 1.5
100
101
100°C80°C60°C40°C20°C
0 0.5 1 1.5
100
101
100°C80°C60°C40°C20°C
100
101
102
AbsorptionDesorption
2 2.5 3 3.5
• Dynamic pressure composition isotherms
• Pressure-composition quasi-static equilibrium isotherms (Sieverts)
• Kinetic Sorption Measurement (Arrhenius)
• Desorbed Gas Analysis (Mass Spectrometer)
Measurement Capabilities
What is AGAS Mano
Specifications• Measuring Pressure Range: 0-100 bar• Measuring Temperature Range: 298K – 473K (standard), 77K – 773K (optional)• Pressure measurement accuracy: ±0.35% of the full range• Hydrogen flow rate in dynamic mode: 0 – 5 Nml/min (customizable)
AGAS is an advanced gas sorption analysis systemAGAS is simple and user-friendlyAGAS combines the quasi-static (Sieverts) and dynamic
measurement modes in a single deviceAGAS comes with an integrated data analysis software
Pres
sure
[bar
]
1/T [K-1]
Van’t Hoff plot
cH2[H/M]
p eq [b
ar]
Dynamic Pressure-Composition Isotherms (pcI) Measurement and Determination of the Enthalpy and Entropy of Reaction
Absorption Desorption
cH2[H/M]
p eq [b
ar]
The pcI are measured at a constant flow rate of 1 Nml/min-g and allow determining the enthal-py and entropy of reaction of (LaCe)(NiCoMn)5
• Reaction Enthalpy:
-26.7 ± 1.7 kJ/mol (Abs.), 28.2 ± 1.7 kJ/mol (Des.)
• Reaction Entropy:
101.0 ± 5.1 kJ/mol (Abs.), 101.8 ± 5.1 kJ/mol (Des.)
0.05 0.06 0.07 0.08 0.09 0.12
3
4
5
6
7
8
100°C80°C60°C40°C20°C
0 0.5 1 1.5
10 0
10 1
Abs. @ 5 Nml/minAbs. @ 3 Nml/minAbs. @ 1 NmlDes. @ 1 Nml/minDes. @ 3 Nml/minDes. @ 5 Nml/minExtrapolation to 0-Flow
0 0.5 1 1.5100
101
Dynamic ModeQuasi-Static Mode (Sieverts)
0 1 2 3 4 52
3
4
5
6
7
8
AbsorptionDesorption
50 100 150 200 250 300 350 400 450 5000
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0
1
2
3
4
5
6
7
8
Measurement ResultsComparison of the Quasi-Static
(Sieverts) with the Dynamic (Mass Flow) pcI Measurement
Pres
sure
[bar
]
H2 Concentration [%mass]
Comparison of the quasi-static (Sieverts) method with the dynamic (Mass-Flow) meth-od for the pcI (Absorption) measurement of
(LaCe)(NiCoMn)5 at 40°C.
cH2 [%wt]
p [b
ar]
Determination of the “True” Equilibrium Pressure by Extrapolation to Zero Flow Rate
p 0 [b
ar]
Flow rate [Nml/min]
The measurement of pcI curves at different flow rates allow determining the “true” equilibrium pressure by extrapolation to zero-flow.
Determination of the Critical Tempearture and H-H Interaction Energy Using the
Lattice Gas Model
ln [p /
p0(1
-cH/c
H)2 ]
cH [H/(LaCe)]
The lattice gas model allows determining the in-teraction energy between two hydrogen atoms in the metal lattice and the critical temperature at which the two-phase mixture no longer exists.
• H-H interaction energy: ε0=2.12 eV
• Critical temperature: TC=542°C
Thermo-Desorption of Complex Hydrides
Measurement of the hydrogen desorption flow as a function of the different temperatures.
Flow
rat
e [c
m3 /
min
]
Temperature [°C]
m(H
2) [m
ass
%]
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