颗粒过滤器除尘效率的实验研究与数学建模

为开发煤热解工艺的高温荒煤气脱尘技术,在错流式固定床颗粒过滤实验平台上测试了表观气速、粉尘浓度、过滤介质粒度和床层厚度等关键参数对除尘器除尘效率的影响。结果表明,粉尘浓度在10.0~96.8 g/m~3范围内增大且颗粒床表层过滤作用显著时,除尘器效率先增大后减小;大粒径瓷球对应的除尘效率较低,但压降降低显著;床层厚度增大,过滤器的除尘效率和压降均增大。过滤器运行初始状态,床层过滤过程属于深层过滤,随粉尘在床层内沉积,迎流面表层过滤作用增强,可直接脱除45.0%~52.0%的粉尘。建立了描述错流式颗粒过滤过程的一维非稳态数学模型,使之可以预测过滤平台在不同操作条件下的净床除尘效率和粉尘沉积率。应用该模型,预测热解气气氛下过滤器(床层厚度0.6 m,填充6 mm瓷球)的净床除尘效率有所下降,为82.94%。

Mathematical modeling and experimental study on dust removal efficiency of granular filtration bed

A cross-flow granular filtration fix-bed platform was set up to develop the high temperature pyro-gas and dust separation technology.Influence on the separation efficiency caused by key parameters including superficial gas velocity,dust concentration,filtration grain size and bed thickness was investigated.The results show that the separation efficiency first increases and then decreases when dust concentration rises within the range of 10.0-96.8 g/m3.Filtration bed packed with larger ceramic balls tends to have both lower efficiency and pressure drop.Separation efficiency and pressure drop increase with the thickening of the filtration bed.At initial operation state the filtration mechanism belongs to deep filtering.Along with the dust deposition into the bed,surface layer filtration enhances,which remove 45.0%-52.0% of the dust directly.An unsteady one-dimensional mathematical model is developed to describe the cross-flow filtration process,and to predict the net separation efficiency and dust deposition rate of platform under different operating conditions.The net efficiency of the filtration bed (0.6 m thickness,filled with 6 mm ceramic balls) in pyro-gas atmosphere declins to 82.94% by calculation.