Sulfur dioxide disproportionation for sulfur based thermochemical energy storage

Abstract

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.

Solar Energy on Demand: A Review on High Temperature Thermochemical Heat Storage Systems and Materials

“…Sulfur 78 , which is one of the great advantages of this technology if compared with any other TES process.…”

“…The first reaction occurs at ∼500 °C, while the second takes place between 650 and 900 °C. 78 Sulfuric acid dissociation requires the use of efficient catalysts for reaching stable conversions (e.g., Fe−Cr based catalysts). 78 The second step is the recovery of sulfuric acid and the formation of sulfur (eq 13).…”

“…78 Sulfuric acid dissociation requires the use of efficient catalysts for reaching stable conversions (e.g., Fe−Cr based catalysts). 78 The second step is the recovery of sulfuric acid and the formation of sulfur (eq 13). This is the lowtemperature step, taking place at around 150 °C.…”

Effective reduction of graphene oxide using sulfur dioxide-containing chemical compounds

“…Its use as an antioxidant and preservative in food bottling (Gabriele et al 2018;Giménez-Gómez et al 2017), as an energy storing material (Wong et al 2015), in super-battery production (Liu et al 2018) and in the pharmaceutical industry alongside nano-carriers (Shen et al 2018) is the most preferred applications of (SO 2 )g. In order to use SO 2 in the pharmaceutical and food industries, it is desirable to have a high degree of purity; however, small amounts of SO 2 are sufficient for these industries. Therefore, alternative methods for the disposal of waste SO 2 should be investigated.…”

Reversible formation of alcohol solvates and their potential use for heat storage

“…Besides coupled thermogravimetric-mass spectrometric (TG-MS) [30,31], thermogravimetric analysis/differential scanning calorimetric (TGA/DSC) [32] techniques are generally applied in heat storage studies. We believed that Raman spectroscopy [33,34] and X-ray powder diffraction (XRD) [35] methods are informative in sample characterization. Use of above techniques on structural changes in salt alcoholates is quite unique.…”