Solar-Driven Coal Gasification in a Thermally Irradiated Packed-Bed Reactor

Abstract

Coal gasification for high-quality synthesis gas production is considered using concentrated solar energy as the source of high-temperature process heat. The solar reactor consists of two cavities separated by a radiant emitter plate, with the upper one serving as the solar absorber and the lower one containing the reacting packed bed that shrinks as the reaction progresses. A 5 kW prototype reactor with an 8 cm depth, 14.3 cm diameter cylindrical bed was fabricated and tested in a high-flux solar furnace, subjected to solar flux concentrations up to 2600 suns and packed-bed temperatures up to 1440 K. The reactor is modeled by formulating the 1D unsteady energy conservation equation that couples conductive−radiative heat transfer with the reaction kinetics and solving it by the finite volume technique for a transient shrinking domain. The overall reaction rate was determined experimentally by thermogravimetry, while the effective thermal conductivity was determined experimentally in a radial heat flow ove...