以石灰石和石灰为脱硫剂的镁强化FGD过程对比研究

目前石灰石和石灰仍是湿式烟气脱硫(FGD)的2种主要脱硫剂。因二者物理性质不同，其利用率和脱硫率等随操作参数的变化规律亦有差异。为了分析这种差异，依据旋流板塔镁强化石灰石／石灰FGD实验结果，研究得出了脱硫率等随操作参数变化的拟合方程，计算了不同浆液pH值下石灰石和石灰的利用率，对比分析了相关方程的导数。结果表明，镁强化石灰FGD过程的脱硫率因入口气体SO2浓度的增大而下降的幅度小于镁强化石灰石的过程；在设备条件等相同的情况下，为实现高效净化，镁强化石灰石FGD过程的操作液气比大于镁强化石灰的过程；石灰的利用率随浆液pH值的降低而提高的幅度较小，而在保证脱硫率的前提下，降低操作pH值则可有效提高石灰石的利用率。

Comparative Study on Limestone with Lime for Desulfurization in FGD Process with Adding Magnesium Sulfate

At present, limestone and lime are still used as two main absorbents in wet flue gas desulfurization (FGD) process. Because of the difference of their physical properties, changes of utilization and removal efficiency with operating factors are different, for analyz--ing this difference, regression equations of removal efficiency etc. versus operating factors were obtained according to experimental results of magnesium-enhanced limestone/lime FGD processes in rotating-stream tray scrubber. Limestone and lime utilization was calculated under different slurry pH value, and the concerned equations derivatives were compared and analyzed. According to the results of the study, decrease of SO2 removal efficiency of magnesium-enhanced lime FGD process due to increase of inlet SO2 concentration was smaller than that of magnesium-enhanced lime- stone FGD process; to achieve high removal efficiency under the same conditions of equipment etc., the required operating liquid-to-gas ratio of magnesium-enhanced limestone process should be greater than that of magnesium-enhanced lime process; the effect of slurry pH value on lime utilization was relatively small, while decreasing operating pH value could effectively increase limestone utilization as long as the removal efficiency was satisfied.