Numerical investigation of PM2.5 size enlargement by heterogeneous condensation for particulate abatement
Numerical investigation of PM2.5 size enlargement by heterogeneous condensation for particulate abatement
复制标题
通过非均相冷凝增大 PM(2.5) 尺寸以减少颗粒物的数值研究
DOI：
10.1016/j.psep.2019.03.018
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发表时间：
2019-05-01
影响因子：
7.8
通讯作者：
Su, Mingxu
中科院分区：
文献类型：
--
作者：
Fan, Fengxian;Zhang, Sihong;Su, Mingxu
以PM2.5为核心的蒸汽非均相冷凝是一种有前途的方法，可以扩大颗粒尺寸，从而促进现有惯性分离器的后续颗粒物去除。然而，对PM2.5颗粒物非均质凝结增粗的研究却非常缺乏，这对优化颗粒物减排过程具有重要意义。在这项研究中，颗粒尺寸分布的演变，由于蒸汽非均质冷凝的多分散不溶性PM2. 5的表面上的模型的基础上的经典的非均质成核理论和冷凝液滴生长理论。利用该模型，数值研究了操作参数对非均相冷凝后颗粒尺寸分布的影响。结果表明，在接触角较小时，多分散的细颗粒转变为单分散的粗颗粒，而在接触角较大时，非均相冷凝后产生双峰粒径分布。较高的蒸汽饱和比、较高的气体温度、较长的停留时间和较大的几何平均粒径有利于PM2.5粒径的增大和颗粒物的减少。粒径的几何标准差对PM2.5的粒径扩展影响不大。模型预测的蒸汽非均相冷凝后的颗粒尺寸分布与实验数据吻合较好。(C)2019年化学工程师学会。Elsevier B.V.出版，保留所有权利。
Vapor heterogeneous condensation with PM2.5 as nuclei is a promising approach to enlarge the particle sizes and thus facilitate subsequent particulate abatement by the existing inertial separators. However, the investigation on PM2.5 size enlargement by vapor heterogeneous condensation, which is important to optimize the particulate abatement process, has been largely lacking. In this study, the evolution of particle size distribution due to vapor heterogeneous condensation on the surfaces of polydisperse insoluble PM2.5 was modelled based on the classical heterogeneous nucleation theory and the condensation droplet growth theory. Using this model, the effects of operational parameters on the particle size distribution after heterogeneous condensation were numerically investigated. The results show that the polydisperse fine particles shift to monodisperse coarse particles at a small contact angle, whereas bimodal particle size distribution after heterogeneous condensation is generated at a large contact angle. Higher vapor saturation ratio, higher gas temperature, longer residence time, and greater geometric mean particle size are beneficial to PM2.5 size enlargement and subsequent particulate abatement. Moreover, the geometric standard deviation of particle sizes has little effect on the PM2.5 size enlargement. The model predictions of the particle size distribution after vapor heterogeneous condensation match well with the experimental data. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.