THERMOGRAVIMETRIC STUDY OF REGENERABLE SULFUR SORBENTS FOR H2S RETENTION AT HIGH-TEMPERATURE

The behaviour of a series of mixed oxides including zinc titanate (ZT) , zinc ferrite (ZF) and zinc ferrite doped with copper (ZFC) or titani um (ZFT) oxides as hot-gas desulphurizing sorbents was investigated by thermogravimetric techniques. The stability of sorbents against reduc tion was strongly affected by the temperature that limits the use of t he prepared sorbents > 600 degrees C. Intrinsic rate constants for the reaction between H2S and the sorbents at 550 degrees C were obtained in a thermal balance. The incorporation of titanium and copper oxides to zinc ferrite improved the sorbent reactivity. Five sulphidation-reg eneration cycles were also carried out in order to provide information concerning the durability of sorbents. A loss of sorbent activity wit h the cycle number due to sintering in regeneration was found for zinc ferrite sorbents but not for titanium-containing sorbents. (C) 1997 E lsevier Science B.V.