Abstract: The vertical thermosiphon reboiler is the core equipment in the ethylene glycol regeneration and recovery system. Aiming at the problems of low vaporization fraction of the reboiler and vibration of the flow pattern for the outlet tube, the design of the outlet tube diameters of 200 mm and 300 mm is compared by using the software Aspen EDR. The heat transfer enhancement of the reboiler has done by inserting twisted tape into the heat exchange tube. The influences of the outlet tube diameter, the twist rate of twisted tape and the thickness of twisted tape on the reboiler vaporization fraction and the flow pattern in the tube are studied The results show that the flow pattern range line is basically the same under different outlet tube diameters; when the outlet tube diameter of the reboiler tube side is 200 mm, the overall operating efficiency is higher than that of the tube diameter of 300mm; by inserting twisted tape, the total heat transfer coefficient and vaporization fraction of the reboiler are improved, the flow pattern in the tube is optimized, and the heat exchange performance of the reboiler is improved; the lower twist rate of the twisted tape, the better the heat transfer efficiency of the reboiler; the comprehensive strengthening effect of the reboiler is the best when the thickness of the twisted tape is 1 mm and its twist rate is 4.76.