Investigation of nano-CuO/mesoporous SiO2 materials as hot gas desulphurization sorbents

Gases from gasification processes contain H2S 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 H2S 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 SiO2 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 SiO2. The H2S 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 H2S 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.