DISCUSSION
In our recent work, the synergistic effect of amino acids and spiral agitation on promoting hydrate growth kinetics was evaluated24. Excitingly, the composite system performs well under mild conditions, and a storage capacity of 146 V/V was obtained in 0.3 mmol/L L-methionine solution under 3.8 MPa and 60 rpm. However, when the revolving speed was reduced to 30 rpm, the promoting effect became poor, and the maximum methane storage capacity of 128 V/V was only achieved in the system of 2 mmol/L L-methionine. In comparison, the synergistic effect of nano-promoters and spiral agitation performs better on promoting the growth kinetics of hydrates, and the excellent promotion was also observed under milder conditions. It is clear from Figure 10 that methane storage capacities in -COO-@PSNS and -SO3-@PSNS systems are 141.33 V/V and 147.28 V/V separately for 30 rpm, which increase by 10.4% and 15.1% compared with L-methionine under the same conditions, and methane uptake rate in -COO-@PSNS systems is faster than that in amino acid systems. Moreover, it is worth noting that the concentration of nano-promoters is only 1 mmol/L, which is also easy to synthesize and store. Therefore, in view of the excellent promoting of nano-promoters under mild conditions, its synergistic effect with spiral agitation provides a new insight for the industrial production of SNG technologies.