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• Microscopic and macroscopic experiments on the effects of non-ionic anti-agglomerants were carried out. • The adhesion force between hydrate particle and droplet on wall surface was affected by liquid bridge and its solidification. • The optimal concentrations of CDEA and AEO-9 to reduce adhesion between hydrate particle and droplet on wall surface are 0. 5 wt% and 0. 1 wt% respectively. • The feedback torque is the smallest for the CDEA and AEO-9 solutions at their optimal concentrations respectively. Non-ionic anti-agglomerants (AAs) are important agents to prevent hydrate deposition. In this study, the microscopical experimental results show that the adhesion force between hydrate particle and droplet on wall surface mainly depends on the force of the liquid bridge under low subcoolings; while it is dependent on the resultant force of the liquid bridge and hydrate shell under high subcoolings. Below the concentration of 2 wt%, the optimal concentrations of CDEA and AEO-9 to reduce the adhesion are 0. 5 wt% and 0. 1 wt%, respectively. The adhesion force decreases gradually with the increase of their concentrations when their concentrations are lower than the optimal values, but gradually rises with the increase of their concentrations when higher than the optimal values. Moreover, the hydrate formation experiments in a stirred reactor show that the feedback torques are the smallest at the optimal concentrations of them, which is consistent with the results of the microscopical experiments. [ABSTRACT FROM AUTHOR]