蒸汽相变促进WFGD系统脱除PM_(2.5)的协同作用分析

蒸汽相变作为预处理措施能显著提高常规除尘设备对PM2.5细颗粒的脱除效率,但对于水汽含量低的原始燃煤烟气蒸汽耗量太大,限制了工程应用,而在燃煤电厂湿法烟气脱硫(WFGD)过程中,烟气降温增湿,再添加少量蒸汽就可以建立PM2.5凝结长大所需要的过饱和环境,进而实现WFGD系统对PM2.5的协同高效脱除。在分析蒸汽相变促进PM2.5脱除影响因素的基础上,结合湿法脱硫过程传热传质特性,定性分析了脱硫塔塔前、塔内和塔出口添加蒸汽对WFGD系统脱除PM2.5的促进作用,并提出具体工艺方案。

Desulfurization System by Heterogeneous Condensation

Removal efficiency of PM_(2.5) can be considerably improved if they are enlarged by heterogeneous condensation of water vapor. However, it cannot be directly applied to removal of fine particles from coal fired flue gas due to low moisture content. In wet FGD process, hot flue gas contacts normal temperature scrubbing liquid, causing gas phase temperature to decrease and relative humidity of flue gas to increase, which make it possible to remove PM_(2.5) efficiently by adding a little vapor. The cooperative removal of PM_(2.5) from wet FGD by adding steam in gas inlet and above the scrubbing liquid inlet of the scrubber, and at the outlet of scrubber respectively was qualitatively analyzed, which is based on factors affecting heterogeneous condensation and mass and energy transfer process during desulfurization.