Conversion of boehmite to higher alumina phases by direct irradiation with concentrated light: Numerical modelling and experimental verification

Solar energy conversion to chemicals and fuels receives progressively more attention. Many of the possible conversion routes incorporate particles or could be transformed into particle-phase reactions, with one of these promising routes being aerosol reactors directly illuminated with concentrating light. Directly irradiated particles in aerosol phase can combine the advantages of fast heat and mass transfer rates with higher optical efficiencies compared to indirect solar reactors. Therefore, this study utilized mathematical models and qualitative experiments to demonstrate the potential of such reactors and processes using the conversion of aluminum hydroxide particles (Boehmite or gibbsite) to higher Alumina phases. In particular, the numerical simulations showed the prospect of fine tuning a concentrated light driven aerosol (particle) process to achieve higher selectivity of specific products by taking advantage of the very high heat transfer rates and details of the reaction mechanism. This was also verified with complementary experiments of an immobilized bed of particles exposed to short duration concentrated light pulse.