Hydrate-based acidic gases capture for clean methane with new synergic additives

Abstract

The widespread need for carbon dioxide (CO2) and hydrogen sulfide (H2S) removal from potential gaseous fuel processes associated with upgrading of natural gas, biogas and landfill gas has led to a continuing interest in developing acid gas capture technologies. This work experimentally investigated the hydrate-based acidic gases (CO2 and H2S) capture for clean methane (CH4) fuel from biogas or natural gas with new synergic additives, which comprised physical gas solvent (TMS) and traditional hydrate promoter (TBAB). The results show that, with the synergic additives, the equilibrium hydrate formation pressures were moderated by about 90% relative to pure water, the selectivity of CO2 over CH4 and the selectivity of H2S over CH4 could achieve 18.56 and 11.38, respectively. Compared with TBAB, the synergic additives could improve the hydrate formation rate and the gas storage capacity by 149% and 84%, respectively. Furthermore, the promotion effect could be enhanced when with the help of H2S. It has been shown that CO2 and H2S could be synchronously captured through the hydrate formation process. It will be of importance to the fundamental study of enhancing gas hydrate formation process, and of practical significance for the hydrate-based application industry.