Sulfur dioxide disproportionation is one of three reaction steps that make up the sulfur based thermochemical cycle used for thermal energy storage of concentrated solar power. The characteristics of this reaction were studied using thermodynamic modeling and laboratory measurements. Modeling results showed full disproportionation can only be achieved at pressure. The reaction driving force is enhanced by system pressure but declines with increasing temperature. Appropriate water to sulfur dioxide ratio also drives disproportionation. Batch experiments showed that reaction rate increases with temperature. A catalyst survey identified homogenous iodides as catalysts that can improve the reaction rate by up to twenty times while increasing the apparent extent of disproportionation. The dependence of disproportionation rate on sulfuric acid concentration was established via constant pressure experiments. Means to recover the iodide catalyst from sulfuric acid and molten sulfur for reuse were demonstrated. Modeling and test results were used to establish a design concept for a sulfur dioxide disproportionation reactor system capable of rapidly generating sulfur as required for the sulfur based thermochemical energy storage technology.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.