A Study of Zn−Ti-Based H2S Removal Sorbents Promoted with Cobalt and Nickel Oxides

To improve the sulfur-removing capacity of Zn−Ti sorbent, new Zn−Ti-based H2S removal sorbents promoted with cobalt and nickel were prepared and tested in a packed bed reactor at middle-temperature conditions (H2S absorption at 480 °C and regeneration at 580 °C). The new sorbents showed excellent sulfur-removing capacities without deactivation even after 15 cycles of absorption and regeneration, whereas the conventional Zn−Ti sorbent continuously deactivated. The nickel and cobalt that permeated the Zn2TiO4 worked not only as active sites during the sulfidation process, but also as a structural stabilizer to prevent a change of physical properties of the sorbents during multi-cycle reactions. Also, the cobalt additive increased the regeneration capacity of the Zn-based sorbents by supplying heat to initiate the regeneration reaction of zinc at lower temperatures while the nickel additive prevented SO2 slippage that originated from the cobalt sulfate.