Mn−Cu and Mn−Cu−V Mixed-Oxide Regenerable Sorbents for Hot Gas Desulfurization

Abstract

Porous Mn−Cu and Mn−Cu−V mixed-oxide sorbents prepared by the complexation technique were tested for high-temperature removal of H2S in the presence of hydrogen gas. Sorption experiments carried out at 627 °C in a fixed-bed reactor showed higher reactivity and also higher sulfur retention capacity (over 0.15 g of S/g of sorbent) for the Mn−Cu mixed oxide than for the Mn−Cu−V mixed oxide. Successive sulfidation−regeneration cycles demonstrated that the Mn−Cu mixed oxide was also more stable than Mn−Cu−V, maintaining its activity and about 90% of its sulfur retention capacity at the end of five cycles. Although formation of some MnSO4 was observed during regeneration at 700 °C with a gas mixture containing 6% oxygen in nitrogen, this did not cause significant reduction in the activity of this mixed-oxide sorbent. It was also shown that a previously proposed deactivation model gave good predictions of the experimental breakthrough curves obtained with these sorbents.