Kinetics of Mn-based sorbents for hot coal gas desulfurization. Quarterly report, December 15, 1993--March 15, 1997

Manganese-based sorbents have been investigated for the removal of hydrogen sulfide (the primary sulfur bearing compound) from hot coal gases prior to its use in combined cycle turbines. Four formulations of Mn-based sorbents were tested in an ambient-pressure fixed-bed reactor to determine steady state H{sub 2}S concentrations, breakthrough times and effectiveness of the sorbent when subjected to cyclic sulfidation and regeneration testing. In previous reports, the sulfidation and regeneration results from cyclic testing done at 600{degrees}C were presented. Manganese-based sorbents, with molar ratios > 1:1 Mn:Substrate were effective in reducing the H{sub 2}S concentration in simulated coal gases to less than 100 ppmv over five cycles. Actual breakthrough time for formulation C6-2-1100 was as high as 73% of breakthrough time based on wt% Mn in sorbent. Regeneration tests determined that loaded pellets can be fully regenerated in air/steam mixture at 750{degrees}C with minimal sulfate formation. In this report, the results from cyclic crush strength tests, Sulfur profile tests and cyclic testing at 550{degrees}C and lower flowrate cyclic testing are presented. Crush strength testing done after 5 cycles showed decreases in strength from 12.6% to 57.9%. Cyclic testing at 550{degrees}C showed pre breakthrough concentrations as low as 10 ppmv. Cyclic testing done at 2 L/min and 3 L/min did not show any significant difference in pre breakthrough concentrations or capacity