预热器提升管内粉料径向浓度的试验研究  

Experimental investigation into radial distribution of powder in the heat-exchange pipe of a suspension preheater

作　　者：刘文欢[1,2] 陈延信[1] 徐品晶[1] 徐德龙[1] 安卫东[1] 李辉[1] 

机构地区：[1]西安建筑科技大学粉体工程研究所,陕西西安710055 [2]西部建筑科技国家重点实验室(筹),陕西西安710055

出　　处：《西安建筑科技大学学报（自然科学版）》2008年第6期810-814,共5页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：国家"863计划"资助项目(2003AA33X060)

摘　　要：采用光纤浓度探头针对6个不同高度的预热器提升换热管截面,做了粉料径向相对浓度分布的试验研究.结果表明:换热管中物料运动的加速段,物料同气流间存在较大的相对运动速度,且湍流强度大,物料浓度涨落最显著.换热管中物料运动的匀速段,流场充分发展,物料浓度分布的特点是中心低而边壁高的不均匀分布.换热管中心区的颗粒浓度较低,浓度分布曲线较平坦,由中心向边壁靠近,物料浓度单调递增,且近壁处分布曲线变陡.从换热管底部向上,边壁区的物料浓度随轴向位置变化明显而中心区的物料浓度变化较小,物料沿径向浓度分布的不均匀程度减小.增大系统的固气比,换热管内的物料总平均浓度增大,同时径向不均匀性增大,物料下冲高度增大.物料的径向相对浓度大小和下料方式有很大关系.颗粒在换热管中的运动并不只是单一的向上运动,同时还伴有横向的迁移运动.n order to optimize the suspension preheater system and investigate the heating-exchange and mass-transfer process of bulk solids in gas phase, particle concentrations were measured at 6 levels along the axial direction of the heat exchange pipe with the superficial gas velocity ranging from 12 to 21m/s and different solids loading. The results indicated that in the sect of the riser pipe where particles are accelerating, there is a remarkable relative velocity between particle and gas and turbulence strength of gas is strong and the phenomenon of the particle concentration fluctuation is obvious. In the sect where particles move with uniform velocity ,the solids concentrations are distributed non-uniformly in radial direction, with lower particle concentrations occurred near riser center and higlaer near the pipe wall. In this sect the flow field is fully developed. Relatively flat curve of materials concentration distribution was observed in the central zone. From the center to the wall, the solids concentration increased monotonously and the distribution profile becomes steeper at the wall. From the pipe bottom to the top, the solids concentration in the wall Vicinity significantly varies with vertical position, while around the riser center line the particle concentrations varied insignificantly. As the solids loading increase, the overall average particle concentration increases in the whole heat-exchange pipe, the dispersion distance of the powder as well as the radial fluctuation of particle concentrations increase. The feeding method of the raw meal has a remarkable effect on the particle concentrations. In the pipe the movement of powder is not only upwards but also in lateral migration.

关 键 词：预热器 换热管 物料相对浓度 径向浓度分布 

分 类 号：TQ170.2[化学工程—硅酸盐工业]