振动流化床造粒特性的实验研究

Granulation Process in A Vibro-fluidized Bed Spray Granulator

实验在尿素颗粒和油菜籽颗粒晶种上喷涂尿素熔融液或尿素溶液,使晶种以层式生长机理造粒。着重讨论了初始粒径,晶种种类,料液流率,流化气速,振动强度以及喷嘴高度等参数对颗粒成长的影响。实验结果表明:在流化气速U=1.86Umf时油菜籽晶种的生长率明显大于尿素晶种;增大料液流率和晶种初始粒径,减小流化气速、振动强度以及减低喷嘴高度都有利于颗粒长大;当U=(1.5～2)Umf时,料液流率存在一个极值(W<8.5kg/h);振动的引入使操作气速降低20%。

Urea particles and oilvegetable seeds as initial particles were used to study granulation process in a vibrofluidized bed,where the initial particles grew in a layered manner by spraying melt urea solution on them and reached the required granule size.The experimental results show that at fluidizing gas velocity U=1.86Umf,the oilvegetable seeds give higher growth rate than the urea particles.Larger initial particle size and liquid spraying rate and lower gas velocity,vibrating intensity and nozzle position are preferred conditions for the growth of particles.To keep the particles from cohering,however,liquid spraying rate should be limited to less than 8.5 kg/h for U=(1.5～2.0)Umf.