CO2 removal from synthesized ternary gas mixtures used hydrate formation with sodium dodecyl sulfate(SDS) as additive

In order to investigate the hydrate formation kinetics of the ternary gas mixtures containing sodium dodecyl sulfate (SDS) and evaluate the applicability of hydrate based gas separation (HBGS) technology to biogas, synthesized ternary gas mixture (CH4/CO2N2) hydrate formation processes with different concentrations of SDS were investigated comprehensively in this work. The changes in the gas composition during the hydrate formation process, the gas consumption of the hydrate, the effective reaction time, the recovery factor of CH4, the split ratio of CO2, and the microscopic promotion mechanism of SDS for the hydrate were studied. The results indicated that the addition of SDS increased the hydrate reaction rate and gas consumption compared with those in a pure water system. The promotional effect of SDS improved with an increase in its concentration. The maximum CO2 split ratio was 0.95, at a driving force of 4.4 MPa and 0.05% SDS concentration. The maximum CH4 recovery factor was 3.18, at a driving force of 6.4 MPa and 0.03% SDS concentration. SDS promoted the formation of CO2 hydrate more strongly than that of CH4 and N-2 for the ternary gas mixture. In summary, HBGS technology exhibited a good separation effect under two experimental conditions. (C) 2019 Elsevier Ltd. All rights reserved.