کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7044006 | 1456925 | 2018 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Filtration efficiency and loading characteristics of PM2.5 through commercial electret filter media
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موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
تصفیه و جداسازی
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چکیده انگلیسی
Atmospheric PM2.5 pollution has been attracting much public attention for decades because of its adverse health effects. China and other Asian countries are frequently exposed to high PM2.5 concentrations, and filtration techniques through HVAC systems and indoor air cleaners are often used to mitigate PM2.5 in indoor environments, e.g. commercial and residential buildings, schools, and hospitals. Electret filter media provide lower pressure resistance and are frequently used in air purification systems. However, existing test standards, e.g. ASHRAE 52.2-2012, only challenge filters with particles larger than 300â¯nm which makes it impossible to assess filter performance at the most penetrating particle size (MPPS) since the inherent MPPS of electret media is smaller than 100â¯nm. In this study for investigating the performance of the electret filter media against PM2.5, the filter media were first challenged with monodisperse particles of 3-500â¯nm (the majority of PM2.5 number concentration resides in this range) at face velocities of 0.05, 0.25 and 0.5â¯mâ¯sâ1 to obtain initial efficiency curves. Then the time-dependent efficiencies during the loading process were investigated using polydisperse NaCl particles which mimicked the size distribution of typical atmospheric PM2.5. Additionally, the effects of fiber charge and particle charge on initial efficiency and loading characteristics were evaluated by intentionally removing the fiber charges and charging the particles bipolarly (neutralized) or unipolarly. Results showed that the effects of fiber and particle charges on initial efficiency enhancement depended on particle sizes. The polarization force enhanced the collection of particles larger than â¼20â¯nm particles, the image force enhanced the collection of particles smaller than â¼100â¯nm, and the Columbic force enhanced the collection of particles smaller than â¼300â¯nm. Charging the particles unipolarly can slow down the reduction of electrical efficiency during loading and enhance the minimum efficiency by 10-30% for 50-500â¯nm particles, compared to that of bipolarly charged particles. A model using an electric degradation parameter and mechanical collection efficiency raising factor was applied to explain the performance of electret media in loading processes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Separation and Purification Technology - Volume 195, 29 April 2018, Pages 101-109
Journal: Separation and Purification Technology - Volume 195, 29 April 2018, Pages 101-109
نویسندگان
Min Tang, Drew Thompson, De-Qiang Chang, Sheng-Chieh Chen, David Y.H. Pui,