Effectiveness of Waste Iron Oxide as a Sorbent Alternative in Hot Gas Cleanup

Z. Huque, R. Khan, and D. Mei (USA)


Coal Gasification, Iron Oxide, Desulfurization, Sorbents


The development of hot gas desulfurization sorbents is one of the most critical issues for both Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) power systems. Zinc oxide, zinc ferrite and zinc titanate were the leading mixed metal oxides for hot gas desulfurization applications. These sorbents have high sulfur capacities and can remove hydrogen sulfide from coal gasifier gas down to less than 20 ppm. But the biggest disadvantages of these sorbents are the high cost and the problems associated with decrease in crush strength and density, loss of sorbents, and deterioration of structure. In this current paper an experimental study of the feasibility of using waste iron oxide as a possible cheap alternative to existing sorbents were performed. Tests were performed with reducing KRW-Gas stream with 5500 ppm of hydrogen sulfide concentration mixed with mixtures of coal ash and waste iron oxides. Results suggest that waste iron oxides could be used as a possible disposable sorbent alternative to reduce the concentration level of hydrogen sulfide to a safe level. The coordination of space velocity, residence time, and reaction temperature could develop an efficient and economical hot gas desulfurization system.

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