A Conceptual Catalytic Receiver Reactor for Solar Thermal Sulfuric Acid Decomposition

Abstract

The highest‐temperature step in iodine–sulfur and hybrid–sulfur thermochemical cycles for hydrogen generation is the sulfuric acid decomposition reaction. To efficiently utilize solar energy directly to operate this step, the development of a catalytic solar receiver reactor is essential. A cavity‐type reactor coupled to a solar dish and a numerical analysis of the reactor predicting the reaction conversion as a function of the solar absorption coefficient is presented in this study. The catalytic receiver reactor consists of a double‐walled quartz cylindrical tube to form the cavity and a flat quartz plate window for entry of the concentrated solar radiation. Two catalysts, Fe1.8Cr0.2O3 and Fe2O3/SiO2, are tested in the solar catalytic receiver reactor and SO2 yields of ≈40% and 38% are observed, respectively. Numerical analysis of the reactor is performed and a reaction conversion–absorption coefficient correlation is established. For the catalytic packed bed assuming absorption coefficient of 0.65, a steady‐state temperature of 1212 K is achieved, accomplishing an approximate theoretical efficiency of ≈56%. The numerical analysis suggests that by utilizing a material of construction with high absorption coefficient, significantly enhanced sulfuric acid decomposition can be achieved by the cavity‐type solar receiver reactor.