High temperature thermodynamics and applications of rare earth compounds containing oxygen and sulphur in fuel gas desulphurization and SOx and NOx removal

Advanced sulfur control concepts

“…Therefore, free energy data from Barin et al (1993) for 52 compounds including a number of the gaseous sulfur allotropes, and metal compounds of cerium, cobalt, manganese, and molybdenum were added to the data base. Data for a single compound of interest, Ce,O,S(s), were taken from Kay et al (1993) since that compound was missing from the compilation of Barin et al…”

“…As much as 75% of the sulfur released during regeneration was in elemental form, with most of the remainder as H2S. Kay and Wilson (1989) and Kay et al (1993) have reported that elemental sulfur is formed during the regeneration of cerium oxysulfide, Ce,O,S, at conditions similar to those used for FeS regeneration.…”

High temperature desulfurization over nano-scale high surface area ceria for application in SOFC

“…Sorption rate constant K o and the deactivation rate constant K d were correlated as a function of temperature using by Arrhenius equations (Eqs. (9) and (10)). …”

“…They reported complete conversion of CeO 2 to CeO 2 S during sulfidation in the temperature range of 500-700 o C and regeneration of Ce 2 O 2 S to CeO 2 by using SO 2 . According to phase diagrams, relevant reactions were reported by Kay et al [9] as:…”

“…Meng et al [8] and Kay et al [9] first described the use of cerium oxide (or ceria) sorbents for high-temperature desulfurization. It is well established that ceria and metal oxide (e.g., Gd, Nb, and Zr) doped cerias provide high oxygen storage capacity, which is beneficial in oxidation processes.…”