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The influence of admixture of Al2O3 on the ZnO-TiO2 sorbent of sulphurization-regeneration trough oxidation in air at high temperature

Domenii publicaţii > Chimie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: Madelene Dãncilã, Ion Untea, Viorel Bǎdiliţǎ

Editorial: Revista de Chimie, 58 (7), p.640-645, 2007.

Rezumat:

High Temperature Gas Desulfurization (HTGD) is the main process for hydrogen sulphide removal from gases at high temperature. Higher efficiency and lower cost are achived by using zinc oxide based sorbents as they can effectively reduce the H2S content in gases to ppm levels and can be regenerated for multicycle operation. Zinc titanates sorbents, a mixed-metal oxides prepared by combining ZnO and TiO2 at high temperature, is currently one of the leading sorbents for HTGD process. This experimental work focuses on modification of the reactivity and regenerative characteristics of ZnO-TiO2-Al2O3 sorbents. Depending on the ZnO:TiO2:Al2O3 molar ratio and the preparation and calcination conditions, several phases of zinc titanates, zinc aluminate and aluminium titanate can be formed. TiO2 and Al2O3 act as supports for mechanical structure strengthening, as stabilisers against reduction of the ZnO to volatile metallic zinc in reducing atmosphere and prevent attrition or sintering of the sorbent during the regeneration process allowing a multiple desulphurizing-regeneration cycles. Regeneration of sulphuretted sorbents ZnO-TiO2-Al2O3 is strongly influenced by the temperature, a complete regeneration with high rate of the oxidation reaction being possible at 600-7000C temperature range. Also, Al2O3 induces a high thermal stability of the sorbent allowing a direct regeneration of sulphuretted sorbents with air at high temperature.

Cuvinte cheie: High Temperature Gas Desulfurization, zinc titanates sorbents, sorbent regeneration