基于双循环多级水幕塔的无机盐强化烟气脱硫研究

Flue gas desulfurization enhanced by inorganic salts using double circulation and multi-stage water film tower

在传统双循环脱硫塔基础上对双循环多级水幕塔进行改进;上下段采用不同pH控制,以多级水幕代替复杂的多层喷淋,增强气液传质效果。研究结果表明:浓度均为0.2 mol/L MgSO4和Na2SO4促进石灰石溶解的效果明显,SO42-可促进石灰石溶解,而Cl-对石灰石溶解起抑制作用;MgSO4和Na2SO4对石灰石转化率的影响与空白实验相比最高分别增加15%和10%,反应时间缩短2 h,而NaCl对石灰石转化率的影响与空白实验结果相比低约3%;MgSO4和Na2SO4的加入明显延长pH缓冲时间,MgSO4加入时pH从7.9降至3.6需要2 h;MgSO4和Na2SO4能明显提高脱硫效率,0.2 mol/L MgSO4和Na2SO4对应的脱硫效率分别比非强化时提高7%和4%;MgSO4和Na2SO4强化后石灰石利用率与非强化时相比分别提高11%和5%。

Double circulation and multi-stage water film tower were retrofitted based on the traditional double cycle desulfurization tower.Different pH and multi-stage water film towers were used to substitute the traditional complicated multilayer sprayers to increase mass transfer impetus.The results show that the limestone has the best solubility when the concentration of MgSO4 or Na2SO4 is 0.2 mol/L.The sulfate radical can promote the limestone＇s solubility,but chloridion may restrain it.The limestone＇s transformations influenced by MgSO4 and Na2SO4 increase by 15% and 10% respectively compared with those without additive＇s enhancement and its reaction time can be shortened by 2 h,but its transformation influenced by NaCl decreases by 3% compared with that without additive＇s enhancement.It can delay buffer time of pH when inorganic salt is added,and needs 2 h when pH decreases from 7.9 to 3.6 and MgSO4 is added.Desulfurization efficiency can increase 7% and 4% when the concentration of MgSO4 or Na2SO4 is 0.2 mol/L.The limestone＇s utilities improve 11% and 5% respectively when MgSO4 or Na2SO4 is added compared with those without additives＇ enhancement.