Preparation of Graphene-amine Nanofluid for Absorption of Carbon Dioxide (CO2) and Hydrogen Sulfide (H2S) from a Natural Gas Stream in a Wetted Wall Column

    In this study, it was shown that how CO2 and H2S were removed from a natural gas stream, using a nanofluid containing nanoporous graphene in Diehanolamine (DEA). Before running the experiments, the appropriate values were chosen for the nanosheet dosage and the liquid and gas flow rates in the absorption experiments, which were performed in a laboratory scale wetted wall column. In the experiments, the nanosheet concentration ranged from 0.005 to 0.5 wt %.The surfactants and ultrasonic treatment  were used to prepare stable nanofluids. It was indicated that using nanoporous graphene in DEA significantly affects on CO2 and H2S absorption in comparison to DEA. The absolute zeta potential values of nanofluids were greater than +35 mV. The effect of different parameters including nanosheet concentration as well as the CO2 and H2S concentration, in the feed gas stream (two different samples) on simultaneous absorption of H2S and CO2 from CO2-H2S-CH4 gas mixture was studied. In the case of using sample #1, (i.e. Feed gas mixture composition: % H2S and 3% CO2 in balance of CH4), an improvement in CO2 absorption to 39% and H2S absorption to 9% was observed at 0.1 wt% of nanoporous graphene/DEA nanofluids.