Investigation of nano-CuO/mesoporous SiO 2 materials as hot gas desulphurization sorbents

Abstract

Gases from gasification processes contain H 2S which is highly harmful for almost all catalyst materials and metal constructions such as in IGCC plants. Metal oxides and/or their admixtures are widely used for the removal of H 2S from gases at high temperatures. These sorbents, however, suffer from several problems which adversely affect their performances. In this study, a new method was explored to prepare sorbents from nano-size (sub-micron) CuO supported on SiO 2 materials. Three sorbents with 38.5 wt.%, 41.5 wt.% and 49.6 wt.% Cu contents were prepared and characterized. Results indicated that, the produced materials are mesoporous composite type materials of nano-size CuO and amorphous SiO 2. The H 2S adsorption characteristics of the prepared sorbents were studied in a laboratory scale fixed-bed reactor through sulfidation–regeneration cycles in the temperature range of 788–838 K at atmospheric pressure. The average sulfur uptake capacities of the sorbents, based on the breakthrough point H 2S concentration of 20 ppm, were determined to be in the range of 2.38–2.91 g S/100 g sorbent after 3 cycles. Although the process at high temperatures appeared to disturb the structure of the sorbents to some extent, the drop in their sulfur adsorption capacities remained limited.