双层滤料颗粒床除尘器预热过程的仿真研究

颗粒床除尘器在脱除含尘热解煤气粉尘前需要进行预热工作, 从而避免因携带的焦油冷凝造成设备损坏无法工作. 为研究此过程, 采用FLUENT软件对一个大型颗粒床除尘器的预热过程进行数值模拟. 该除尘器壳体内径4.8m, 高度22m, 壳体内沿垂直中心线上安装6个内径3.4m、高1.8m的过滤床. 模拟结果表明, 当预热气在过滤床流速为0.1m?s-1时, 壳体内壁面上下最大温差为76.9℃, 除尘器从10℃加热至500℃需要98880s. 本次模拟采用的阶跃式分段预热制度使除尘器壳体内壁面上下温度差较小, 减小了因温度不均匀造成的材料变形, 模拟中的滤料和壳体温度及预热所需的时间也可给实际的工程应用提供参考.

Simulation of preheating of dual-layer granular bed filter for gas dust removal

To avoid the equipment being damaged and malfunctioned due to the tar condensation, the granular bed filter should be preheated before being used for removing the dust contained in the pyrolysis gas. Such preheating process of a large granular bed dust collector is simulated by FLUENT software. The shell inner diameter of the dust collector is 4.8m and the height is 22m. Six filter beds with inner diameter of 3.4m and height of 1.8m are installed along the vertical center line in the shell. The simulation results show that when the flow rate of the preheated gas in the filter bed is 0.1m?s-1, the maximum temperature difference between the upper and lower surface of the shell is 76.9℃. It takes 98880s for the dust collector to be heated from 10℃ to 500℃. The stepped preheating system adopted in this simulation makes the temperature difference between the upper and lower sides of the inner wall of the dust collector shell smaller, which reduces the material deformation due to uneven temperature. The temperature of filter and shell in the simulation and the time required for preheating can also be used as a reference for practical engineering applications.