Experimental investigation on the synergistic influence of tetra-n-butyl ammonium bromide(TBAB) and cyclopentane(CP) in hydrate-based gas separation

•Study of hydrates formed by a CH4/CO2/N2 mixture with compound additives.•Synergistic effects of CP + TBAB on hydrate based gas separation were evaluated.•Hydrates with multiple structures (I, II, and semi-clathrate) were formed.•The maximum CH4 recovery 1.37 and the CO2 split ratio was 0.791 when using CP and TBAB solution.