喷动流化床气体混合特性实验研究

Experimental Investigation of Gas Mixing in Spout-fluid Bed

在300 mm×30 mm×2 000 mm的喷动流化床煤部分气化炉冷态试验装置上,在喷动区和环形区同时采用了不同示踪气体的方法,获得了在不同喷动气流速和流化气流率这2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,考察了喷动区与环形区之间的气体交换特性和环形区的气体混合特性。结果表明,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,且流化气在环形区的混合加强。喷动气和流化气的浓度沿床层高度依次降低。此外,结合CCD拍摄的流动结构图像,从气相质量交换的角度对床内的气固流动特性进行了讨论。

Gas mixing （GM） in spout-fluid bed was investigated by simultaneously injecting different tracer gas （TG） into the spout region and the annular region, respectively. The concentrations of TG at various bed locations were obtained. A multi-channel pressure signal analysis system and high-resolution digital camera were used to determine the flow patterns. Effects of two most important operating parameters （spouting gas velocity and fluidizing gas flow rate） on GM were examined with flow patterns. The results show that gas transfer from the spout region to the annular region and GM in the annular region are promoted by increasing spouting gas velocity. Gas transfer from the annular region to the spout region and GM in the annular region are promoted by increasing fluidizing gas flow rate. The distributions of spouting gas and fluidizing gas decrease with bed height.