Solar Hydrogen via Water Splitting in Advanced Monolithic Reactors for Future Solar Power Plants
Christos Agrafiotis;
Contact PSA : Alfonso Vidal;
Colaborative Project. Joint Technological Initiative. 2008 Call.
Total Budget: 2.100 k€. Budget CIEMAT: 175 k€.
1st January 2010 – 30 December 2012
Solar thermochemical hydrogen production faces the enormous Challenger of achieving scale up of solar concentrating Technologies and reactor sable to operate at Powers of several MW. At the present time there are developments, many of them tested by the DLR and CIEMAT at the PSA facilities, which make it possible to operate with volumetric receivers at temperatures above 1000ºC. The reason for the Hydrosol project is making use of the accumulated experience in materials development and systems with catalytic matrices using SiC with monolithic channels that were validated successfully during the SOLAIR Project. Impregnation of these ceramic matrices with mixed ferrites makes it possible to use the volumetric receiver/reactor concept in hydrogen production. The possibility of using this monolithic reactor with the ferrite fixed to a substrate greatly facilitates the separation of oxygen and hydrogen in alternating charge and discharge stages.
The main purpose of the HYDROSOL-3D project is the detailed study of a 1-MW solar thermochemical plant producing H2 by water splitting. The main idea comes from the technology developed and achievements in the preceding HYDROSOL I and HYDROSOL 2 projects which introduced the concept of solar monolithic multi-channel reactors in the form of a beehive panel for generating hydrogen by splitting the water molecule. The HYDROSOL 3D Project will make use of all the previous experience, concentrating on the design of a commercial plant and will include all the activities necessary for the construction of a 1-MW demonstration plant based on this technology.

The second stage of the Hydrosol-3D’s predecessor Hydrosol-II) ended in September 2009 and its purpose was the evaluation of a 100- kW receiver in a power tower plant at the Plataforma Solar de Almeria using mixed ferrites impregnated on ceramic SiC matrices. The results led to the first basic recommendations on operating strategies, especially on operation of the solar field. These tests demonstrated the operating capacity of the HYDROSOL II reactor in a field of heliostats with power tower for of semi-continuous production of hydrogen.

Taking advantage of the above, HYDROSOL-3D concentrates on the future commercialization and involvement of all the activities necessary to prepare the construction of a 1-MW demonstration solar plant based on the HYDROSOL technology. In this respect, HYDROSOL-3D includes pre-design of the entire plant, including the solar hydrogen reactor and all the upstream and downstream units necessary to introduce the reagents and separate the products, as well as plant construction and maintenance costs.

The reactors designed and control strategies will be validated by experiments going from laboratory to small-scale and pilot reactors integrated in solar power towers to make sure that they are up-scalable. At the same time, the design of control software with its algorithms and controllers necessary for automatic operation of this plant will be developed and integrated in process simulation software.

Two alternative scenarios will be analyzed: Adapting the hydrogen production plant to an existing solar power tower field or developing a new one “from scratch”, completely optimizing hydrogen production to the solar plant. The most promising option will be selected and in continuation will be analyzed in detail, developing the distribution of the plant, its definition and detailed dimensioning of all its components as well as the control system and simulation of complete plant operation.

Finally, a technical-economic study will be made and a market analysis to find out the feasibility of process scale up to MW scale, by calculating the costs necessary to build a 1-MW demonstration plan and the costs of supply and producing hydrogen. Realistic market penetration scenarios will also be calculated for the technology and the possible synergies with other technologies that complement the project, in order to demonstrate that combination of the power tower technology is a feasible way to produce large amounts of hydrogen by water splitting at a reasonable cost, without any type of greenhouse gas emissions, facilitating the path to the sustainable future of a purely renewable hydrogen economy.

APTL (Greece), DLR (Germany), Total (France), HYGEAR (Netherlands), CIEMAT (Spain).