School of Energy and Power Engineering, Shandong University, Jinan, 250061, Shandong, China.
Environ Sci Pollut Res Int. 2021 Jun;28(21):27273-27282. doi: 10.1007/s11356-020-12192-y. Epub 2021 Jan 28.
The synergistic removal of multi-pollutants, including particles, SO, and NO, is a key concern in the process of flue gas purification, during which the supersaturated environment is an essential premise for the nucleation and deep reduction of particles. The condensation of desulfurized flue gas using heat exchangers can not only recover condensed water and latent heat but also create supersaturated environment to promote the flue gas purification. In this study, an experimental system for desulfurized flue gas condensation is established. The effect and associated mechanism of condensation process on the removal of multi-pollutions are clarified. The results show that particles with an aerodynamic diameter larger than 2.5 μm accounts for 50% in mass proportion. The flue gas temperature drop has positive influence to the increase of the ideal supersaturation degree, which is beneficial for the removal of particles (especially when the aerodynamic diameter is less than 1 μm), SO, and NO. The ideal supersaturation degree slightly reduces with the rise of inlet flue gas temperature, which can promote the removal efficiency of small particles, while weaken that of large particles, SO, and NO. Caused by the increase of flue gas flow rate, the nucleation process weakens, reducing the removal efficiency of all pollutants (particles, 45.2-28.3%; SO, 27.5-14.5%; NO, 21.5-15%). On the whole, the increase of the ideal supersaturation degree contributes to the synergistic removal of pollutants especially particles with smaller radius in the flue gas. The reduction of particles with aerodynamic diameter less than 1 μm is conductive to the synergistic removal of SO and NO.
协同去除多种污染物，包括颗粒物、SO 和 NO，是烟气净化过程中的关键关注点。过饱和环境是颗粒物成核和深度还原的必要前提。利用换热器冷凝脱硫后的烟气不仅可以回收凝结水和潜热，还可以创造过饱和环境，促进烟气净化。本研究建立了脱硫烟气冷凝的实验系统，阐明了冷凝过程对多种污染物去除的效果和相关机制。结果表明，空气动力学直径大于 2.5μm 的颗粒物占质量比例的 50%。烟气温度下降对理想过饱和度的增加有积极影响，有利于颗粒物（尤其是空气动力学直径小于 1μm 的颗粒物）、SO 和 NO 的去除。随着入口烟气温度的升高，理想过饱和度略有降低，这有利于提高小颗粒物的去除效率，同时削弱大颗粒物、SO 和 NO 的去除效率。由于烟气流量的增加，成核过程减弱，降低了所有污染物（颗粒物，45.2-28.3%；SO，27.5-14.5%；NO，21.5-15%）的去除效率。总的来说，理想过饱和度的增加有利于协同去除烟气中的小半径污染物，特别是颗粒物。空气动力学直径小于 1μm 的颗粒物的减少有利于 SO 和 NO 的协同去除。
