J. Phys. IV France 07 (1997) C1-685-C1-686
The Solar-Driven Coal/Fe3O4 Redox SystemT. Tamaura1, M. Tsuji1, K. Ehrensberger2 and A. Steinfeld2
1 Research Center for Carbon Recycling and Utilization, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152, Japan
2 Laboratory for Energy and Process Technology, Paul Scherrer Institute, 5132 Villigen PSI, Switzerland
The solar-driven endothermic reaction of coal and magnetite was studied for mixing solar and fossil energies. The overall reaction can be represented by CHx + Fe3O4 = CO + 3FeO + 1/2xH2 where x depends on the coal(x= 0.2 in our study). Laboratory experimental studies with an equimolar mixture of anthracite coal and Fe3O4 powder using an infrared furnace showed rapid gas evolution above about 1200°C and 1bar, producing FeO(s) and a gas mixture containing a CO/CO2 molar ratio of 4.5. Solar-driven experiments were conducted using a high-flux solar furnace. Samples were directly exposed for short time intervals to a solar flux irradiation of 300 W/cm2. The carbon content decreased rapidly after only 1 second exposure, suggesting efficient heat transfer and chemical conversion by direct absorption of concentrated solar energy at the reaction site. The proposed solar thermochemical process offers the possibility of performing simultaneously the gasification of coal and reduction of iron oxide, and for producing a fuel with an upgraded calorific value.
© EDP Sciences 1997