Experimental investigation on highly potent inhibitors of natural gas hydrate in oil-free flow system

•A new anti-agglomerant (NAA) suitable for oil-free system is further studied.•The NAA and MEG are combined to give scope to their respective advantages.•A flow loop to evaluate the performance of inhibitors is built.•The optimal compound proportioning of inhibitors to maintain safe flow is obtained.•The mechanism of compound inhibitor consisting of NAA and MEG is proposed.