基于减缓石膏雨的脱硫塔流程优化

Optimization of Process in Desulfurization Tower based on Slow down of Gypsum Rain

安徽某电厂脱硫塔内流速分布不均匀,造成除雾器效率低,加剧了石膏雨现象。采用数值模拟方法对脱硫塔流场进行优化。模拟结果表明,改造前喷淋层流场波动剧烈,除雾器流场分布不均,除雾效率只有74.41%,导致石膏雨生成。入口改造成倾斜向下,烟气"抬头"现象得到改善,各截面CV提高5%,除雾器效率提升4.44%;在改造入口条件下加弧形导流板后,喷淋层CV达到50%,除雾器CV更是达到70%,除雾器效率提升8.12%,远优于加竖直导流板的方案;喷淋层靠边界中空锥喷嘴换成实心锥喷嘴后,有效防止了高速烟气贴壁逃逸,喷淋层逃逸系数降低0.1,喷淋层CV提高近10%,除雾器效率提升6.46%。经过结构优化,该脱硫塔内流场均匀性改善,液滴贴壁逃逸现象减弱,塔内脱硫率提高,石膏雨现象减轻。

The flow field of a Anhui＇s power plant FGD is not uniform, resulting in low efficiency of the demister and exacerbating the gypsum rain phenomenon. Numerical simulation method is used to optimize the flow field of the UFG. The simulation results show that the flow field of the spray layer is violent and flow field distribution is uneven and the efficiency of the mist is only 74.41% leading to the formation of gypsum rain. Entrance into the slope down, the ＂rise＂ of the phenomenon has been improved, the Cv of each cross section increased by 5% and the efficiency of the mist eliminator improved by 4.44%; Under the condition of the reformation, the arc guide plate is added, the CV of the spray layer is 50% and the CV of mist eliminator is 70% in addition to the efficiency of mist eliminator 8.12%, far superior to that of a vertical guide plate; the hollow cone nozzle of spray layer on the boundary changing for solid cone nozzle effectively prevent the escape of high speed flue gas, escape coefficient of spray layer e decreased by 0.1,CV of the spray layer increased by nearly 10% and the efficiency of the mist eliminator improved by 6.46%. After the structure optimization, the flow field uniformity of FGD is improved and airflow escape near the wall can be weaken and the desulfurization efficiency of FGD can be increased and gypsum rain phenomenon can be weaken.