旋/直复合流化下循环流化床脱硫塔内的气液分布特性研究

A Study of Gas-liquid Distribution Characteristics in a Circulating Fluidized Bed Desulfuration Tower Under a Swirling/straight Composite Fluidization Mode

应用激光相位多普勒颗粒分析仪(PDA)和双回路抽气式热电偶测试了旋/直复合流化方式下烟气循环流化床脱硫塔内的液滴和气相温度的分布规律。结果表明,在整个干燥过程中液滴的分布基本呈中心区域高边壁区域低的趋势;与常规直流流化方式相比,当相对高度H/D>2时,旋流的存在从整体上提高了塔内各点的液滴干燥速度,而且旋流量越大,干燥速度越快;在喷嘴雾化区域内,烟气温度分布呈中间低边壁高的趋势,当相对高度H/D<2时,旋流的存在加剧了这种趋势,但有无旋流对液滴完全干燥后的气相温度及分布影响不大;综合来看,旋/直复合流化方式能够有效减轻粘壁现象。

By using a laser-phase Doppler analyzer (PDA) and a dual-loop extraction-type thermocouple,tested was the liquid droplet and gas-phase temperature distribution law in a flue gas circulating fluidized-bed desulfuration tower under a swirling/straight composite fluidization mode.The measurement results show that the liquid droplet distribution in the whole drying process basically assumes a tendency of being more accumulative in the central zone and less so in the side wall zones.When compared with the conventional straight flow fluidization mode with the relative height H/D being greater than 2,the existence of a swirling flow can enhance the liquid droplet drying speed at various points in the tower on the whole.Moreover,the greater the swirling flow rate,the quicker the drying speed.In the nozzle-atomized zone,the flue-gas temperature distribution tends to assume a low value in the middle and a high one at the side walls.When the relative height H/D is lower than 2,the existence of a swirling flow can intensify the above tendency.The presence or absence of swirling flows,however,influences little on the gas phase temperature and distribution when the liquid droplets have been completely dried.From a comprehensive viewpoint,the swirling/straight composite fluidization mode can effectively ameliorate the wall-sticking phenomenon.