(455a) Hybrid Sulfur Cycle Flowsheets for PEM Electrolyzers with SO2 Vapor Feed

Hybrid Sulfur cycle flowsheets that have been developed for the DOE Nuclear Hydrogen Initiative typically feature SO2-depolarized electrolyzers (SDEs) in which the anode is fed a solution of SO2 dissolved in sulfuric acid. An alternative SDE configuration, in which the anode is fed wet SO2 vapor, is also being considered. This offers several advantages as well as disadvanates when compared to the liquid-fed version. Changes in the Hybrid Sulfur flowsheet necessitated by switching to an SO2 vapor-fed SDE are examined in this paper. Flowsheet performance is estimated based on the results of Aspen Plus simulations and compared with that of earlier flowsheets that use liquid-fed SDEs.