大型铝电解预焙槽气体焙烧启动传热特性

Heat transfer characteristic of gas baking method for heating electrolytic cell

利用铝电解预焙槽槽底导热的三维数学模型 ,研究大型铝电解预焙槽气体焙烧启动时 ,槽底阴极的升温速度、温度分布与加热制度的关系 ,并讨论气体焙烧启动加热的最少时间及阴极下表面所能达到的最高温度 .确定了实际采用的加热制度 ,并论证了其加热工艺的合理性 .

This paper has numerically investigated the relationship between opportune thermal method and temperature distribution of heating hall cell using non steady three dimensional heat transfer model of the cathode of cell. It was found that when the cell was heated in ultimate or fast rate (heating the cell in 33 to 50 h) to raise the cathodic temperature, it would cause high thermal gradients that lead to objectionable thermal stress in the article which can result in thermal shock cracking of the article, although the temperature can be raised to the desired degree; if completing the heating in 70 h with the step rate, to consider the moisture transpiration and the carbonization of cathodic material, thermal gradients were low to 100 ℃/m in cross section, and the surface gradients were low to 30 ℃/m, and the temperature distribution is substantially uniform. In real practice, excellent results by using this method have been gotten. The utmost less time to heat cell using the gas heating methods is also researched, and so is the utmost high temperature of the cathode bottom.