Abstract:

The characteristics of high humidity,high sulfur and high acid dew point of calcination tail gas of rotary kiln of titanium dioxide shortens the life of metal heat exchanger.On the basis of summarizing the existing problems of the previous waste heat utilization methods of the rotary kiln tail gas,a long-life and easy-to-maintain bushing heat pipe waste heat utilization device was presented.The device is made up of separate heat pipe bushings connected by inner pipe elbows and flanges.The calcination tail gas crosses the double-layer heat pipe bushings vertically,and heat is transferred from the calcination tail gas to the heating medium through the phase change of the phase change medium.Then the steam required by the production of TiO₂ was obtained.Compared with single-layer gravity heat pipe heat exchanger,the bushing heat pipe exchanger life span of the double-layer tube is obviously prolonged; the elbow of the single-layer tube connecting the heat pipe bushings does not contact with calcination tail gas,which greatly reduces the corrosion to the single-layer pipe.The bushing heat pipe heat exchanger is used in the 3.6 m×58 m titanium dioxide calcining kiln,it can produce 11.2 kt annually water vapor with 0.9 MPa pressure,brings enormous economic benefits to enterprises.

Key words: calcination tail gas, titanium dioxide, heat pipe bushing, phase change heat