hydrogen from regenerative energy power sources...
TRANSCRIPT
Hydrogen from Regenerative Energy Power Sources: pressurised alkaline electrolyser with high efficiency and
wide operating range The EU-Project „RESelyser“
The RESelyser Project is supported by the European Union's Seventh Framework Programme (FP7/2007-2013) for the Fuel Cells and Hydrogen Joint Technology Initiative under grant
agreement n° [278732]
R. Reissner1, G. Schiller1, E. Guelzow1, Y. Alvarez Gallego2, W. Doyen2, A. Funke3, H. de Bie3, J.R. Bowen 4
1 2 3 4
Alkaline water electrolysis – advantages and problems
• Well established technique up to large scale systems • Cheap materials • Gas purity problems at low load and high pressure • Electrode stability when electrolyser off • System adaptation to use with RES
New approaches to solve the problems
• double layer diaphragm with internal KOH supply (“E-bypass membrane”) and adapted cell concept
New approaches to solve the problems
• double layer diaphragm with internal KOH supply (“E-bypass membrane”) and adapted cell concept
• Coated nickel electrodes for low overpotentials and long-term stability with RES load profile. Coating by
plasma spraying
New approaches to solve the problems
• System design adapted to RES power profile
New approaches to solve the problems
Example solar and wind power profile on a cloudy May day in Southern Germany Data source: DLR Stetter, Brinner
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400
600
800
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0 2 4 6 8 10 12 14 16 18 20 22 24
Sola
r irr
adia
tion[
W/m
^2]
Time [h]
solar irradiance0
0.5
1
1.5
2
2.5
3
0 5 10 15 20
Win
d ou
tput
[MW
h] wind output
First results
Diaphragm: double side coated PP spacer-fabric. First version: •total thickness ca. 2.4 mm. •Zirfon(ZrO2/polymer composite) dual layer, individual layer thickness ca. 0.5 mm. •interposed free electrolyte channel, 1.4 mm.
2.4 mm
Internal electrolyte
by-pass
Zirfon® layer 1 0.5 m
m
Zirfon® layer 2
CATHODE
ANODE
Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability
First results
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0
0 200 400 600 800 1000
Nickel-punchedhole sheet
NiAlMo alloycoated
current density [A/cm^2]
Ove
rpot
entia
l [m
V]
Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability XPS-spectra a) newly coated b) activated c) after long operation
First results
binding energy / eV540 538 536 534 532 530 528
inte
nsity
a)
b)
c)
binding energy / eV82 80 78 76 74 72
inte
nsity
a)
b)
c)
Al 2p O 1s
Cathodes coated with NiAlMo (Raney-Nickel with Mo) for reduced overpotentials and increased stability Pore size analysis of VPS- coated and activated NiAlMo electrode 3D SEM measurements planned to see evolution of the pore size distribution
First results
• Anodes coated with NiAl (Raney-Nickel) and various Perowkites and Spinell structure oxides.
• NiAl for electrical conductivity and high surface, oxides for increased oxygen production activity
• Preparation by plasma spraying, activation by leaching out the Al
First results
Summary
• DLR, VITO, Hydrogenics and DTU join their know
how and forces to overcome the problems of gas purity and variable load operation of high pressure, low cost liquid alkaline water electrolysers
• The project RESelyser will run until October 2014 • First steps towards improved diaphragms and
electrodes could be demonstrated