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Single-metal high-temperature solid sorbents for syngas cleaning using Mn, Ca, Fe, Cu, or Mo supported on g-Al 2 O 3 were synthesized, characterized, and tested in a fixed-bed reactor. H 2 S and SO 2 concentrations in the gas after treatment at T = 400 to 700°C were compared with thermodynamic calculations. The Mn-based sorbent showed the best ability to achieve a low sulfur residual in the gas, especially at temperatures above 600°C. Sorbents with Fe, Cu, and Mo gave SO 2 formation in the initial phase, but this could be avoided by a pre-reduction treatment of the sorbent material.

The impact of operating parameters on H2S capture from a syngas mixture by a Mo-promoted Mn-based high-temperature sorbent was investigated. The parameters investigated included temperature, space velocity, H2S concentration in the feed gas, and steam content. The H2S and SO2 concentrations in the gas after passing over a bed of the sorbent were analyzed and compared with thermodynamic calculations. The results confirmed that low temperature, low space velocity, low H2S concentration, and a dry feed were favorable for achieving a low residual concentration of sulfur compounds in the effluent gas. The sorbent was able to reduce the residual H2S concentration to below 1 ppm under all tested conditions. However, the unavoidable steam content in the gas phase had a significant adverse effect on sulfur removal from the gas. An empirical model, containing the three variables, i.e., temperature, space velocity, and H2S concentration in the feed, was developed and can be used to predict the effluent H2S residual concentration after treatment by the 15Mn8Mo sorbent.

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