Thermogravimetric analysis (TGA) and flow-reactor experiments were used to study sulfidationregeneration of highly porous Cu0-A1203 sorbents. In TGA studies, sulfidation of reduced sorbents produced a high-temperature form of digenite (Cu9+xS5) as the major crystalline product. When a platinum pan was used in the TGA, significant sulfur chemisorption on alumina occurred. Sulfur chemisorption on alumina was eliminated by use of a quartz sample pan. Reaction of the mixed-oxide sorbents with a mixture of H2S, H2, H20, and N2 in a packed-bed microreactor, at temperatures between 550 and 800 °C, yielded prebreakthrough outlet-H2S levels considerably lower than those predicted by the sulfidation equilibrium of metallic copper. Independent reduction experiments confirmed that alumina stabilizes CuO against complete reduction to Cu. With this mechanism at work, low prebreakthrough H2S levels are attributed to sulfidation reactions of copper at oxidation states of +1 or +2. The sulfided sorbents were completely regenerable in air/N2 mixtures with no deterioration of subsequent sulfidation performance.Among the most promising new technologies of power generation from coal are gasification integrated with combined-cycle power generation (gas turbine in series with
The reduction and sulfidation of Fe203 and Fe203-Al203 sorbents were investigated by thermogravimetric analysis (TGA). Mixed iron-aluminum oxides were reduced more slowly and by a more complex mechanism than pure iron oxide. Several phases that were responsible for this difference were identified by temperature-programmed reduction (TPR), X-ray diffraction (XRD), BET surface area (BET), and scanning electron microscopy (SEM). Sulfidation of reduced sorbents in the TGA at 600 "C produced two crystalline phases: high-temperature, hexagonal pyrrhotite (Fel,S), and unreacted FeA1204. The reaction of the pure and mixed oxide with a mixture of H2S-H2-H20-N2 was studied in a tubular microreactor to evaluate the performance of these materials as hightemperature H2S sorbents. At 650 "C the mixed oxide yielded considerably lower prebreakthrough outlet H2S levels than the pure iron oxide. Regeneration in pure SO2 and SOZ-air mixtures of sulfided samples resulted in complete conversion of iron sulfide to iron oxide and quantitative recovery of elemental sulfur.
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.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.