The presence of H2S in biogas and natural gas limits their application as fuels due to its corrosivity and sulfur-toxicity. “Molecular basket” sorbents (MBS) is a new sorbent for acid gas adsorption and achieves H2S sorption/desorption at ambient conditions. However, the CO2 in fuel gas strongly inhibits H2S sorption on conventional MBS. In this work, a tertiary-amine-based “Molecular Basket” sorbent was prepared and applied in H2S removal from the gas mixture containing high concentration of CO2. Poly allylamine (PA), polyethylenimine (PEI), and tetramthyl hexanediamine (TMHDA) were loaded on SBA-15, and their H2S sorption performance in the presence of CO2 was comparatively examined. In the presence of CO2, the H2S sorption selectivity dropped dramatically on PA/SBA-15 and PEI/SBA-15, whereas the selectivity of TMHDA/SBA-15 remained stable. Moreover, TMHDA loading level, the sorption temperature, the flow rate, the inlet concentration (H2S and CO2), and the regenerability were studied. Results showed that 15 wt% was the optimal loading level to obtain the maximum breakthrough and saturation capacities. The decrease of temperature and flow rate could improve the H2S sorption capacity. The H2S sorption capacity increased with increasing inlet H2S concentration, and the sorption on TMHDA/SBA-15 was fitted to Langmuir adsorption isotherm. However, the H2S sorption capacity was slightly decreased with the increase of inlet CO2 concentration. The regenerability and stability were good with a mild regeneration condition. The results indicate that tertiary-amine-based MBS is able to remove H2S selectively from the CO2-containing gas mixture.

Hydrogen sulfide removal from carbon dioxide-containing gas mixture on molecular basket sorbents

252nd National Meeting (2016)

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