添加有机酸强化粗颗粒石灰石烟气脱硫

针对传统石灰石湿法烟气脱硫成本高的问题，提出了一种新型石灰石-石膏法烟气脱硫方法，即通过在石灰石浆液中加入有机酸，采用大尺寸石灰石165～200 μm（-80+100目）代替传统的47 μm（325目）以下的细颗粒石灰石进行脱硫，同时在鼓泡搅拌吸收反应器脱硫装置上与传统石灰石湿法烟气脱硫进行了对比实验.研究结果表明，只采用165～200 μm石灰石浆液直接脱硫其脱硫率和石灰石利用率分别为60.7%和44%，但当石灰石（165～200 μm）浆液中乙酸浓度达到10～30 mmol•L^-1，其脱硫率和石灰石利用率分别为95%和93.5%，都达到甚至优于传统石灰石脱硫中的结果，新型石灰石湿法脱硫系统的pH值在正常的脱硫区间波动也较小.在此基础上，提出了添加乙酸促进SO₂吸收的机理.本文提出的新型烟气脱硫方法具有很好的工业应用前景.

Wet flue gas desulfurization by organic acid-enhanced coarse limestone

A new wet FGD process in which SO₂ was absorbed in the bubble reactor using granular limestone and acetic acid was proposed. The main difference as compared with the conventional wet FGD process was to utilize granular limestone directly as desulphurization reagent with simultaneous addition of acetic acid. Thus, the pulverization of limestone, which causes power consumption, could be saved. By using granular limestone（165—200 μm） directly as absorbent only without acetic acid, SO₂ removal efficiency and limestone utilization were too low,60.7% and 44% respectively.By adding 10—30 mmol•L^-1 acetic acid,desulphurization was increased to 95% and limestone utilization was enhanced to 93.5%.The desulphurization efficiency and limestone utilization of using fine limestone were 88% and 92.9% respectively under the same operating conditions.The buffer capacity of system was also enhanced by adding organic acid. With concentrations of 5 and 10 mmol•L^-1 acetic acid, it took 45 min for the pH value to drop from 6.0 to 4.0.Furthermore, with increasing organic acid concentration the effect of buffer action was more obvious. It could better adapt to the fluctuation of SO₂ concentration of flue gas,make operation more flexible, and improve process reliability. The mechanism of promoting SO₂ absorption by acetic acid was suggested.