Date of Award
2006
Degree Type
Thesis
Degree Name
Master of Engineering Science
Program
Electrical and Computer Engineering
Supervisor
Dr.Jon Inculet
Second Advisor
Dr. Maurice B. Bergougnou
Abstract
It is well known that ozone is an effective method of water treatment. Currently ozone is generated with silent dielectric barrier AC discharge in air or oxygen. The study in this thesis covers a new method of ozone generation (electro-ozonation of a water surface) for water treatment at various frequencies and pressures. The electro-ozonation was studied using a modified Vertical Cascade Oxidation Reactor (VCOR) in order to generate a thin film of water over the entire surface of a vertical polished stainless steel plate maintained at ground potential. The Taylor cones which form at random over the thin water film are responsible for the electro-ozonation process. The study covers the ozone generation during electro-ozonation varying: pressure 15 to 30psia, water temperature 10 to 30C, water flow rates 0.350 to 0.750 LPM and oxygen flow rates 0.5 to 1.5 ALPM. 30kV (peak) AC sinusoidal wave high voltage was applied to generate the ozone in all of the above conditions. Tests were performed with both London city tap water and distilled water. Methylene blue in concentration of 0.5mg∕l was used to observe the discolouration produced by the ozone. The modified vertical cascade oxidation reactor included a polished sandblasted stainless steel plate as the ground electrode. The reactor was reinforced with 0.5 inch steel to withstand higher pressures. The gas was fed co-currently downwards with the thin water film on the polished surface of the stainless steel plate. A water and air separator cylindrical unit was designed and built to maintain the pressure of the system and allow a more effective separation of exhausted ozone and dissolved ozone. The experimental steady state results with both London city tap water (tap) and distilled water (dis) showed that an increase in pressure led to a decrease in ozone concentration by [0.008mg∕l (tap), 0.020mg ∕l (dis)] in the dissolved ozone and [30ppm (tap), 50ppm (dis)] in exhausted ozone. An increase in water temperature decreased the ozone concentration by [0.07mg∕l (tap), 0.015mg∕l (dis)] in the dissolved ozone and [50ppm (tap), 100ppm (dis)] in exhausted ozone. Both increases in gas and tap water flow rates decreased the amount of ozone concentration by 0.015mg∕l dissolved ozone and 40ppm in exhausted ozone, respectively. An increase in frequency to 120Hz increased the amount of ozone concentration by [0.015mg∕l (tap), 0.020mg∕l (dis)] in dissolved ozone and [40ppm (tap), 50ppm (dis)] in exhausted ozone.
Recommended Citation
Eng, Richard M.H., "ELECTRO-OZONATION STUDY OF FREQUENCY AND PRESSURE VARIATION ON AC DISCHARGES FOR OZONE GENERATION WITH OXYGEN AND WATER (TAP AND DISTILLED) FLOWING CO- CURRENTLY DOWNWARDS ON A SMOOTH STAINLESS STEEL PLATE" (2006). Digitized Theses. 5058.
https://ir.lib.uwo.ca/digitizedtheses/5058