Decomposition of H2SO4 by Direct Solar Radiation

The sulfur−iodine cycle is one of the most promising thermochemical cycles for hydrogen production. Its coupling with a solar energy primary source is a great challenge to achieve efficient and economically competitive H 2 production. Within this cycle, the decomposition of sulfuric acid plays a key role, with this process being the most energy-demanding reaction step. In this paper, a combined computational and experimental study of the decomposition at high temperature of H 2 SO 4 to SO 2 is presented. The scope of this paper is to present new information and data about the experimental high-temperature decomposition of sulfuric acid carried out in a solar reactor in view of a possible industrial exploitation of this reaction. Starting from a new complete thermodynamic modeling of the process, carried out by investigating the effect of the pressure and the temperature on the SO 2 conversion rates, the study of the high-temperature decomposition of H 2 SO 4 by direct solar radiation using a Fe 2 O 3 -based catalyst was carried out for the first time. The modeling and experimental results obtained are discussed together with the available literature. In summary, SO 2 conversion yields close to thermodynamic predictions were obtained in the temperature range 1050−1200 K at a starting sulfuric acid partial pressure of p = 0.61 bar.