摘要
以PM2.5为凝结核,发生蒸汽凝结能够使得PM2.5粒径增加,以利于后续脱除。了解PM2.5的凝结增长规律对于PM2.5的高效脱除有重要意义。为此,基于凝结增长动力学方程,研究等温和绝热系统中多分散不可溶PM2.5的凝结增长过程,探讨蒸汽凝结后颗粒粒径分布随时间、蒸汽饱和度、温度的变化规律,并将等温和绝热系统中颗粒的凝结增长特性进行对比分析。结果表明,过饱和蒸汽能够迅速在PM2.5表面发生凝结,促进颗粒粒径分布向着大粒径、窄分布的方向发展;相同初始温度条件下,提高蒸汽饱和度可以有效促进PM2.5的增长;相同初始含湿量条件下,温度的较小变化就会引起最终颗粒粒径分布发生显著变化,且温度越低,颗粒凝结增长效果越好;与绝热系统相比,相同初始条件下等温系统中凝结增长所需的时间更长,生成的最终颗粒也更大。
Vapor condensation with PM2.5 particles as nuclei can promote PM2.5 growth to facilitate subsequent particle removal. It is important to understand the factors affecting condensation growth for effective removal of PM2.5. The growth of polydisperse insoluble PM2.5 via vapor condensation in isothermal and adiabatic systems was investigated based on the dynamic equation for condensation growth. The effects of time, saturation degree and gas temperature on particle size distribution were discussed, and particle growth in isothermal and adiabatic systems were compared. The results show that the supersaturated vapor condenses rapidly on PM2.5 particles, which leads to particles with narrower distributions but larger size. The condensation growth can be effectively promoted by increasing saturation degree under same initial temperatures, while a small change in temperature can cause obvious change in final particle size distribution under same initial moisture contents, which is more obvious under lower temperature. Moreover, isothermal systems show longer growth time and larger particle size under the same initial conditions compared with adiabatic systems.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2015年第3期736-742,共7页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金资助项目(51206113
51176128)
上海市科委资助项目(10540501000)
关键词
PM2.5
凝结增长
过饱和蒸汽
数值模拟
PM2.5
condensation growth
supersaturated vapor
numerical simulation
