湿法脱硫协同去除细颗粒物的研究进展

Advances in research on wet desulfurization and synergistic removal of fine particles

石灰石-石膏湿法烟气脱硫(wet flue gas desulfurization,WFGD)工艺具有吸收剂来源广、成本低、脱硫效率高等优点,成为应用最广泛的烟气脱硫工艺。湿法脱硫过程中,燃煤烟气在喷淋浆液的洗涤作用下不仅能高效脱除SO2而且可以协同去除细颗粒物,但同时存在石灰浆液夹带导致出口颗粒物浓度增加的问题。本文首先综述了湿法脱硫的应用现状,对比了湿法脱硫系统前后细颗粒物物性变化,然后概述了应用于湿法脱硫协同去除细颗粒物的新方法,包括脱硫塔内部结构调整以及促进细颗粒物凝聚长大,同时分析了湿法脱硫工艺中采用荷电细水雾吸附细颗粒物并增益脱除SO2的可行性,以期为燃煤电厂细颗粒物排放控制提供借鉴。最后指出未来湿法脱硫技术不仅要实现高脱硫效率,而且能有效脱除未被静电除尘器脱除的细颗粒物,湿法脱硫技术的发展趋势是多种技术耦合实现多污染物的协同脱除。

Limestone-gypsum wet flue gas desulfurization (WFGD) process has become the most widely used FGD process due to its wide source of absorbent,low cost and high desulfurization efficiency.In the wet desulfurization process,the coal-fired flue gas is washed by the spray slurry.Not only SO2 can be removed efficiently,but also fine particles can be synergistically removed.However,there is also a problem that the concentration of the particulate matter in the outlet increases due to the entrainment of the lime slurry.In this paper,the application status of wet desulfurization have been reviewed firstly,the physical properties of fine particles before and after wet desulfurization system have been compared.Then the new methods for synergistic removal of fine particles by wet desulfurization have been outlined.The methods comprise the internal structure adjustment of the desulfurization tower and promoting the agglomeration of fine particles.And then the feasibilities of using charged water mist to adsorb fine particles and facilitating SO2 removal in WFGD process have been analyzed.These methods may provide reference for the control of fine particulate matter emission in coal-fired power plants.Finally,It is pointed out that the future wet desulfurization technology not only achieve high desulfurization efficiency,but also can effectively remove fine particles that are not removed by electrostatic precipitator.The development trend of wet desulfurization technology is to achieve synergistic removal of multiple pollutants by multi-technology coupling.