Investigation of natural gas storage and transportation by gas hydrate formation in the presence of bio-surfactant sulfonated lignin

The hydrate-based solidified natural gas (SNG) technology is a promising approach for natural gas storage and transportation. One challenge of this technology is to enhance the hydrate formation kinetics and achieve mild storage conditions. This work employed a biomass surfactant sulfonated lignin (SL) to enhance CH4 hydrate formation. Meanwhile, the self-preservation effect of CH4 hydrate formed in the presence of SL was investigated using a high-pressure micro-differential scanning calorimeter (HP μ-DSC). The results indicate that 500 ppm SL is an optimum concentration for improving CH4 hydrate formation kinetics among the five SL concentrations (300, 500, 700, 900, and 1000 ppm) tested. At 500 ppm SL, the CH4 hydrate formation rate was increased significantly, and the largest gas consumption was obtained, which was 2.7 times larger than that obtained in pure water under the same temperature and pressure conditions. The gas consumption was also larger than that obtained in the presence of other surfactants (sodium dodecyl sulfate, silicone surfactant, and ethylene diamine tetraacetamide). CH4 hydrate formed in the presence of SL can be stably preserved at 0.1 MPa and 268.15 K due to the self-preservation effect. Therefore, the energy costs, such as system cooling and gas compression, for SNG using SL are lower than conventional natural gas storage and transport technologies. •The kinetics of CH4 hydrate formation was enhanced in the presence of SL.•500 ppm SL is an optimum concentration to promote CH4 hydrate formation.•CH4 consumption at 500 ppm SL is larger than that using pure water or other surfactants.•The self-preservation effect of CH4 hydrate formed in the presence of SL was found.•CH4 hydrate formed at 500 ppm SL can be stably preserved at 0.1 MPa and 268.15 K.