Promoting effect of activated carbon coupled with amino acids on methane hydrate formation for gas storage application

Solidified natural gas has obtained much attention in gas storage applications. However, the slow rate of hydrate formation and the requirement for agitation reactor restrict the technology development. In this work, we study the hydrate formation within activated carbon static reactor coupled with amino acids. The effect of four amino acids, three activated carbon particles and three water-to-AC ratio on hydrate formation was systemically investigated. The tryptophan has the best-promoting performance as promoter on hydrate formation. The conversion ratio and the maximum growth rate is 0.78 ± 0.04 and 23.78 ± 1.38 V·V−1·min−1, respectively. The large activated carbon particles and high water-to-AC ratio provide abundant granular lattice and free water to promote hydrate formation. Compared with the pure L-tryptophan solution system, the maximum growth rate of hydrate increased by 8.9 and 17.3% in middle activated particles size and large size coupled with L-tryptophan. The maximum growth rate of hydrate in the activated carbon static bed coupled with L-tryptophan is 24.2 ± 0.1, 27.9 ± 0.11, and 30.1 ± 0.12 V·V−1·min−1 at water-to-AC ratio of 0.3, 0.5, and 1, respectively. The combination of large-size activated carbon particles, high water-to-AC ratio and the L-tryptophan are very useful scheme designs. This research offers guidelines for process optimization in future large-scale methane storage applications by hydrate.