纳米TiO_2颗粒在声场导向管喷动流化床中的流化特性  

Fluidization Characteristics of TiO_2 Nanoparticles in an Acoustic Spouted-Fluidized Bed with a Draft Tube

作　　者：皮立强 高凯歌[1] 杨兴灿 周勇[1] Pi Liqiang;Gao Kaige;Yang Xingcan;Zhou Yong(Chemical Engineering Institute, Sichuan University, Chengdu 610065, China)

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《化学反应工程与工艺》2016年第2期114-119,共6页Chemical Reaction Engineering and Technology

基　　金：国家自然科学基金(21376151)

摘　　要：在内径120 mm的半圆柱型声场导向管喷动流化床中,以平均粒径290 nm的TiO_2颗粒为原料,高速空气射流为喷动气,考察了操作条件、声参数(频率和声压)对纳米颗粒在声场导向管喷流床中的流态化特性的影响。结果表明:声波可以有效抑制沟流,改善环隙流化质量,防止射流旁路,从而促使粉体稳定循环,加快循环速率;同时声波可以显著地降低纳米TiO_2颗粒的最小喷动速度,声波频率一定时,最小喷动速度随声压的增加而减小;声压一定时,最小喷动速度在声波频率为80 Hz时达到最小值,低于或者高于80 Hz,最小喷动速度都会增大。An experiment was conducted to investigate the effects of operating conditions, acousticparameters(frequency and sound pressure) on nanoparticle fluidization behaviors in an acoustic spoutedfluidized bed with a draft tube. An half-cylindrical column with a diameter of 120 mm and height of 1 200 mmwas used as the column, TiO2 nanoparticles with an average diameter of 290 nm was used as raw materialswhile the high-speed atmosphere jet was used as the spouting gas. It was found that the sonic couldeffectively inhibit the channelings and improved the quality of the annulus to prevent bypass of thehigh-speed atmosphere jet, thus contributing to a stable powder circulation and speed up the circulation ratebetween annulus and the draft tube. Furthermore, the minimum spouting velocity of the nano-TiO2 particleswas significantly reduced by introducing the sound wave. At a constant frequency, the minimum spoutingvelocity decreased as the sound pressure level increased. On the other hand, when the sound pressure levelwas fixed, the minimum spouting velocity was achieved with a critical frequency at 80 Hz, the frequencybelow or above 80 Hz resulted in higher velocity.

关 键 词：纳米颗粒 流态化 最小喷动速度 导向管喷动流化床 高速空气射流 声波 

分 类 号：TQ021.1[化学工程]