套管预热器线性热膨胀问题分析与改进

Analysis and improvement of linear thermal expansion of the casing pre-heater

套管预热器作为氧化铝管道化溶出的核心设备,其工作原理是:利用内、外嵌套的套管管道,内管走矿浆,外管走热源,热量通过管壁传给矿浆,从而使矿浆得到溶出所需的高温。当管道中通入矿浆和热源时,套管内、外管将均受热沿管道方向产生较大线性热膨胀。而由于外、内管受热温度不同,产生的线性膨胀量不同,当两者差值较大时,将对两端的固定管板产生较大的拉托力,可能将管板拉托或迫使内、外管产生失效变形,从而影响到设备的使用安全。本文对重庆南川氧化铝厂、遵义氧化铝厂、贵州华锦氧化铝厂做出的设计改进,分析了套管预热器线性热膨胀问题对设备的影响并提出改进。

As the core equipment for tube digestion in alumina production, the casing pre - heater has the working principle as there are tube - in - tube pipes, the ore pulp flows through the inner tube, the heat source flows through the outer tube, and the heat is transferred through the wall to the ore pulp, so that the ore pulp gets high temperature. When the ore pulp and heat source are flowing through the pipe, both the inner tube and the outer tube have a large linear thermal expansion along the pipeline. Due to the different heating temperatures of the inner tube and the outer tube, the amount of linear ex- pansion is different. When the difference between the two is large, a large pulling force will be generated on the fixed tube plate at both ends, which may cause the failure of the fixed steel plates or the deformation of the inner and outer tubes, thus affecting the safety of the equipment. Based on the design improvements made by Chongqing Nanchuan Alumina Refinery, Zunyi Alumina Refinery and Guizhou Huajin Alumina Refinery, the influence of linear thermal expansion of casing thermal on the equipment is analyzed and the design improvement measures are put forward.