二维喷动流化床内气体混合的实验研究

在300 mm×30 mm×2 000 mm的喷动流化床冷态试验台上,在喷动区和环形区分别采用CO和SO2作为示踪气体的方法,获得了不同喷动气流速和流化气流率这两个重要的操作参数下,不同床层高度上示踪气体的径向分布,考察了床内喷动区与环形区之间气体的混合特性。结果表明,示踪气体在不同床层高度的径向分布呈现较大的差异,并沿床层高度依次降低。在稳定的流动状态下,喷动气速度的增大,使喷动气向环形区的传质加强,也促进了流化气在环形区的混合;流化气流率的增大,气体由环形区向喷动区的传质大于由喷动区向环形区的传质,且流化气在环形区混合加强。在不稳定的流动状态下,气体的径向浓度分布曲线两边出现不对称。

Experiment study on gas mixture in two-direction spout-fluidized bed

Gas mixing in spout-fluid bed was investigated by simultaneously injecting different tracer gas into the spout region and the annular region,respectively.The concentrations of tracer gas at various bed locations were obtained.A high-resolution digital camera was used to record the flow patterns.Effects of two most important operating parameters(spouting gas velocity and fluidizing gas flow rate)on gas mixing were examined with flow patterns.The results show that the distribution of tracer gas concentration at various bed locations differs greatly and decreases with bed height.In the stable flow gas transfer from the spout region to the annular region is promoted by increasing spouting gas velocity.Gas transfer from the annular region to the spout region and gas mixing in the annular region are promoted by increasing fluidizing gas flow rate.In the unstable flow the radial distribution of tracer gas concentration is asymmetry.