Modelling and scaling analysis of a solar reactor for sulphuric acid cracking in a hybrid sulphur cycle process for thermochemical hydrogen production

Thermodynamic Model of a Solar Receiver for Superheating of Sulfur Trioxide and Steam at Pilot Plant Scale

“…The required incident solar power and resulting material temperatures and thermal efficiency is given as function of the sulfuric acid mass flow. The nominal operating conditions of 1 l/min and 57 kW on aperture (mass and irradiation flux density of 0.18 kg m -2 s and 450 kW m -2 , respectively) are an order of magnitude higher compared to the preceding project HycycleS [5], and close to conditions for industrial operation [6].…”

“…More complex receiver and secondary geometries, optimized for optical and thermal efficiency, will be considered for future projects. The presented models as well as more sophisticated dynamic models as reported in [6] will be adapted accordingly, e.g. considering different boundaries and viewing factors of a cavity design.…”

“…For the development of the SOLREF-receiver, a closed cavity shaped receiver, the tool VORECO has been applied to assess the volumetric absorber surface temperature, discretized into several zones [4]. Further related modelling approaches can be found in [6] (volumetric flow receivers) and [8] (transient modelling of a volumetric receiver with reaction).…”

“…Evaporation and decomposition take place in two respective chambers with a directly irradiated porous ceramic structure (volumetric receiver), each closed by a quartz glass window. Due to limitations of kinetics and heat transfer in the depth of the honeycomb, the first few centimeters of the structure act as a solar receiver, heating up the incoming gases, while the remaining structure can virtually be considered an adiabatic reactor [6]. This led to an adapted design of the solar demonstration plant with separation of receiver and reactor in order to validate and later optimize both units independently from each other.…”

Development of the hybrid sulfur cycle for use with concentrated solar heat. I. Conceptual design

“…HyS is the only practical two-step thermochemical cycle with all fluid reactants, which greatly simplifies material handling and processing and reduces capital costs. Various aspects of HyS are the subject of active research internationally as indicated by a quick gleaning of the literature since 2015 [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Both reaction steps have been experimentally validated [16,20] and detailed system designs have been proposed for continuous, steady-state applications [21,22].…”