Annual Report 2006 - Plataforma Solar de Almería

PLATAFORMA SOLAR DE ALMERÍA
reduction in hydrogen generation, because the oxygen separation stage for
reuse of the inert gas would then not be necessary. The final goal is for the
process temperature in the activation stage to be no higher than 1200 K, as
the radiation loss increases with temperature by a power of four. TGA/DTA
have shown that using nitrogen as the gas carrier, weight loss in the ferrites
can be clearly attributed to partial reduction of magnetite. Weight loss and
activation temperature increase when the Ni/Mn ratio decreases, being 0.5%
to 700ºC and 2.57% at 900ºC for Ni/Mn=3 and 0, respectively Figure 3.25.
Although in 2006, hydrolysis testing with hydrogen production has still not
been done, the results found in the activation stage (oxygen desorption) have
been very promising, with theoretical estimates leading to expect hydrogen
production of around 1 to 3 mg H 2 /g ferrite in the water-splitting reaction.
Publication: [3.28]
Solar Hydrogen via Water Splitting in Advanced Monolithic
Reactors for Future Solar Power Plants (Hydrosol-II).
Participants:
Contact:
PSA Contact:
Funding:
APTL (GR), DLR (D), CIEMAT (E), STC (DK), Johnson Matthey
(RU).
Christos Agrafiotis; chrisagr@cperi.certh.gr
Maria Jesús Marcos, mj.marcos@ciemat.es
Cooperative project funded by the EC 6 th Framework Programme.
Total budget: 4,230 k€. CIEMAT Budget: 647 k€.
Duration: December 1, 2005 – December 1, 2009
Motivation: Solar Thermochemical hydrogen production faces the great challenge
of accomplishing solar concentrating technology and reactor scale-up to
be able to operate at several MW power. Undoubtedly, this will be the central
receiver technology, or the heliostat field with tower, which is the only one
that can be adapted for this use. At the present time, there are developments,
many of them tested jointly by the DLR and the CIEMAT at the PSA
facilities, which allow volumetric receivers to operate at temperatures above
1000ºC. The motivation for the Hydrosol-II project is the confidence in being
able to transfer the experience accumulated in materials development and
systems with catalytic matrices using SiC with monolithic channels that were
validated successfully during the SOLAIR project. The impregnation of these
ceramic matrices with mixed ferrites will make it possible to use the volumetric
of receiver/reactor concept for hydrogen production. The possibility of using
this monolithic reactor with ferrites attached to a substrate greatly facilitates
separation of oxygen from the hydrogen by using alternating charge and
discharge stages.
Purpose: The second phase of this project (Hydrosol-II) began in November
2005, and its purpose is demonstration in a 100 kW reactor at the Plataforma
Solar de Almería of H 2 production from mixed Zn ferrites impregnated on SiC
ceramic matrices. The innovation in this design is the use of an intermittent
charge-discharge operating mode. The endothermal stage is performed with
solar illumination so the high-flux solar radiation in the focus generated by a
heliostat field is moved alternately from some matrixes to others to allow the
H 2 to be charged.
The quantitative project goals are:
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