Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-disc horizental contactor (RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet narrow channels at a low rotation speed. For three emulsions included ethanoliwater/2-ethyl-l-hexanol, ethanol/water/ 2-ethyl-l-hexanol/SDS (Sodium Dodecyl Sulfonate) and 2-ethyl-1 -hexanol/water/SDS emulsion, de-emulsification ratios of oil phase could reach 1, 1 and 0.67 respectively at 170 r. min(-1), and de-emulsification ratios increased obviously after agitating 10 min. De-emulsification experiment in the seam indicated that oil droplet sizes in O/W emulsion became larger after de-emulsification. The main de-emulsification mechanism in RHC-D was the coalescence of oil droplets in oil-wet narrow channels. With increase of the rotation speed, oil droplets dispersed better in the aqueous phase. However, de-emulsification effect enhanced due to the increase of the coalescence rate at a bit higher rotation speed. In addition, internal circulation made those O/W emulsions to be broken repeatedly. consequently de-emulsification ratio increased. Repeated de-emulsification through internal circulation might make continuous extraction of ethanol come true at a low rotation speed. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.