复合流化的烟气脱硫循环流化床气固相研究

Gas-solid flow on composite fluidization of swirl-once through flow in CFB-FGD

摘要:

针对常规循环流化床烟气脱硫技术中仍存在的问题,提出了复合流化的烟气脱硫循环流化床.在文丘里管内安装轴向叶片,形成了直流和旋流组合的流化方式,并采用试验和数值模拟相结合的方法研究了气固相冷态流动规律,与文丘里管直流流化的规律进行了比较.结果表明,这种非均匀布风的复合流化方式比直流流化方式提高了切向速度,增加了塔内颗粒的停留时间,提高了颗粒浓度,增强了湍流脉动,加强了横向的扩散与混合,有效改善了流场均匀性,而且流动更快地达到均匀分布,改善了脱硫塔内的流动.复合流化的烟气脱硫循环流化床技术是一项有应用前景的技术.

Abstract:

The authors brought forward composite fluidization structure against the problems in the CFB-FGD.Axial swirl vanes,which formed the composite fluidization of swirl-once through flow,were installed in the venturi.The characteristics of gas-solid flow at cold state were discussed through experiment and simulation.The comparison between the composite fluidization and the once-through fluidization was carried out.As a result,the composite fluidization mode is nonuniform air distribution mode.Its tangent velocity is larger than that of the once-through fluidization,which results in the longer particles residence time,higher particles concentration,stronger fluctuation,and better capability of diffusion and mixture.The uniformity is improved and can be achieved more quickly,which improves the flow field in the composite fluidization.