In the S-I cycle, iodine and sulfur dioxide are combined with water to create two acid phases. The sulfuric acid phase is decomposed at temperatures near 850°C, and the resulting sulfur dioxide is recycled back into the process. The hydriodic acid in the lower phase is decomposed into the product hydrogen and iodine. Sandia National Laboratory (SNL) has teamed with the Commissariat à l'Énergie Atomique (CEA) in France, and industrial partner General Atomics (GA) to construct and operate a closed-loop device for demonstration of hydrogen production by the S-I process. Previous work in Japan has demonstrated continuous closed-loop operation of the S-I cycle for up to one week using glass components at atmospheric pressure. This work aims for operation under process conditions expected at the pilot plant-level and beyond – pressures up to 20 bar using engineering materials of construction.
Staff at CEA is responsible for the acid-generation step. They have built a transportable skid-based apparatus with equipment for generating and separating the two acid phases. SNL is handling the sulfuric acid decomposition section, and likewise have prepared a portable device for execution of this process step. GA is providing equipment for the separation of hydriodic acid from iodine and water and decomposing it into the product hydrogen. The completed integrated device is scaled to produce a minimum of 100 standard liters per hour of hydrogen. This presentation will summarize project goals, work done to date, current status, and scheduled future work on the INERI S-I Integrated-Loop Experiment.