Development of durable mixed-metal oxide sorbents for high-temperature desulfurization of coal gases in moving-bed reactors.

摘要

Mixed-metal oxide sorbents, particularly zinc ferrite and zinc titanate, are being developed for use in hot gas cleanup of coal gas in the integrated gasification combined-cycle (IGCC). For the case of moving-bed systems, the pelletized sorbent moves between the absorber and regenerator as it absorbs H(sub 2)S from coal gas and is regenerated under diluted air. Therefore a mechanically strong and chemically active sorbent is necessary for proper long-term operation of the system. These desired properties depend on the active components in the sorbent, the type and concentration of the binder material, and the sorbent preparation procedure. In the current program, several zinc titanate sorbent formulations have been prepared using a new rounding fabrication procedure, and varying the types of additives/binders (e.g., bentonite and molybdenum) and calcination temperature (1450-1800 (degree)F, 788-982 (degree)C). Comparison with baseline cylindrical formulations was made by measuring attrition resistance, crush strength, thermogravimetric reactivity and bench-scale reactor performance.