DECOMPOSITION OF LIMESTONE IN A SOLAR REACTOR

The thermal decomposition of limestone has been selected as a model re action for developing and testing an atmospheric open solar reactor. T he reactor consists of a cyclone gas/particle separator which has been modified to let the concentrated solar energy enter through a windowl ess aperture. The reacting particles are directly exposed to the solar irradiation. Experimentation with a 60 kW reactor prototype was condu cted at PSI's 90m(2) parabolic solar concentrator, in a continuous mod e of operation. A counter-current flow heat exchanger was employed to preheat the reactants. Eighty five percent degree of calcination was o btained for cement raw material and 15% of the solar input was convert ed into chemical energy (enthalpy). The technical feasibility of the s olar thermal decomposition of limestone was experimentally demonstrate d. The use of solar energy as a source for high-temperature process he at offers the potential of reducing significantly the CO2 emissions fr om lime producing plants. Such a solar thermochemical process can find application in sunny rural areas for avoiding deforestation. Copyrigh t (C) 1996 Published by Elsevier Science Ltd.