Coproduction of Syngas and Lime by Combined CaCO3-Calcination and CH4-Reforming Using a Particle-Flow Reactor Driven by Concentrated Solar Radiation

Abstract

The combined CaCO3-calcination and CH4-reforming process is investigated using concentrated solar energy as the source of high-temperature process heat. The thermodynamic equilibrium composition indicates the coproduction of lime and syngas (H2/CO molar ratio = 1) at above 1200 K and 1 bar. Exploratory experimental runs were carried out with a 5 kW solar chemical reactor comprised of a windowed cavity-receiver containing a flow of CH4 with suspended CaCO3 particles and directly exposed to high-flux solar radiation. At an optimal reactor configuration, CaCO3 and CH4 conversions of 83% and 38%, respectively, were achieved during 11 min of irradiation at a solar concentration ratio of 1884 suns and a nominal temperature of 1223 K. Effecting simultaneously both reactions in a single solar-driven reactor eliminates CO2 emissions derived from the separate fossil-fuel-based production of these two energy-intensive material commodities.