粉煤灰对脱硫用石灰石溶解特性的影响研究

Study on Effects of Flydust on Limestone Dissolution Characteristics for Desulfurization

石灰石-石膏湿法烟气脱硫是我国广泛应用的脱硫技术,其中石灰石(CaCO3)活性对优化脱硫装置的设计,降低脱硫成本,提高脱硫效率显得尤为重要。通过实验对CaCO3活性进行了研究,在固定pH值的条件下,采用酸滴定CaCO3浆液的方法,研究了不同pH值以及粉煤灰对CaCO3溶解率的影响。结果表明,在所测的pH值范围内,较低的pH值有利于CaCO3的溶解,pH值每降低0.5,CaCO3的溶解率增加8%左右。但为了保持吸收溶液的脱硫效果,一般选择pH值=5.0～5.5之间。粉煤灰对石灰石硫酸溶解的影响较小,初始2h内粉煤灰对CaCO3的溶解有较大的促进作用,2h后变为微弱的阻碍作用。

Limestone/gypsum wet flue gas desulfurization（WFGD） technology is being applied widely in the world which is important to decrease its operation cost and optimize the design to improve the desulfurization efficiency. In this paper the activity of limestone was studied under fixed pH value using acid titration limestone slurry method and the effects of different pH value and flydust on the limestone dissolution rate were examined. The results indicates that a lower pH value is favorable for the limestone solution which increases 8% when pH decreases 0.5. The appropriate pH between 5.0-5.5 is recommended at the operation condition. Flydust has little influence on limestone dissolution with sulphuric acid. At an initial 2 hours, it has been a great role in promoting limestone dissolution. But after that, it has showed weak hindering effect on limestone dissolution.