Particulate matter suspended in the atmosphere is a major contaminant and is prevalent in urban environs, reducing the quality of air in the places that the majority of humans reside. Medical research has labelled PM2.5 as a potential risk to human health. To combat this issue, new legislation regarding PM2.5 has been passed. Electrostatic precipitators exhibit a drop in efficiency at ~(0.1-1) μm PM diameter. Therefore, the present work is focused on an investigation of microelectrostatic precipitation technology, for improvement of indoor air quality.Initial work included investigation of impulsive positive energisation, in a specially designed single stage, coaxial reactor, utilizing 250 ns impulses superimposed on dc voltage. Precipitation efficiency for coarse and fine powders has been investigated for various levels of superimposed impulsive and dc energisation in order to identify optimal energisation conditions.Further steps were taken to decouple charging from collection stages in order to optimize the air cleaning process to a greater extent. Precipitation experiments were conducted using ambient air and cigarette smoke. Maximum precipitation efficiency was achieved when both stages were energised, under impulsive and dc energisation in each stage respectively. Analytical work regarding PM charging has also been conducted.Lastly, the coaxial precipitator reactor was scaled-up for possible indoor air cleaning applications. Similarly, impulsive energisation combined with dc voltage at the different stages has been used and proved to increase precipitation efficiency. Test fluids used were beeswax candle fumes and ambient air. Simulations have also been conducted to optimize the ESP process.In conclusion, it has been shown that impulsive energisation of ESPs is highly efficient,100% for particles greater than 250 nm, for PM2.5 in concentrations found in indoor environments. This could potentially help in increasing indoor air quality, with all the corresponding health, working efficiency and ultimately state economic benefits it could achieve.
|Date of Award||1 Oct 2013|
- University Of Strathclyde
|Supervisor||Scott MacGregor (Supervisor) & Igor Timoshkin (Supervisor)|