High pressure hydrogen sulphide adsorption on silica–aluminas

Applicability of amorphous silica–alumina to hydrogen sulphide bulk removal from natural gas has been discussed on the basis of thermodynamic descriptors obtained from single-gas adsorption tests. Experiments performed at 303 K within a pressure range from vacuum to 1000 kPa have shown the prominent role of narrow micropores in determining key adsorption performances, regardless to sample chemical composition. A specific microporous silica–alumina has been proposed as suitable adsorbent according to its (i) hydrogen sulphide Henry’s selectivity over methane; (ii) hydrogen sulphide specific capacity at 500 kPa; (iii) hydrogen sulphide working capacity, assuming an isothermal depressurisation from 500 kPa to 50 kPa; and (iv) textural stability. Activity involving experiments with mixtures resembling raw natural gas has to be planned in order to confirm these promising clues.

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► We provide H2S adsorption isotherms on different silica–aluminas.
► Results point to prominent role of micropores in determining adsorption performances.
► Single-gas (H2S, CO2, CH4) descriptors evidence separation opportunities.
► A sample is proposed for H2S bulk removal from natural gas.