Extraction of Oxygen-Enriched-Air from Water through Vapor Bubble Diffusion

Abstract

Present study deals with the method of extracting dissolved gas from water and the characterization of the extracted gas in terms of its oxygen concentration and the possible extractable gas amount. This topic has at least two important aspects; one is on the usability of the extracted dissolved gas from water which is believed to have higher oxygen concentration than the atmosphere, and the other is on the achievable level of deaeration by using the present deaeration method. In the present study, a degassing process based on micro-vapor-bubble diffusion is proposed and theoretically reviewed based on the physical laws such as Henry’s law on solubility, Fick’s law of diffusion, and the vapor pressure of water as a condition for vapor bubble generation. An experimental apparatus is set up for the present study which is composed of a sealed water tank (0.65m×0.65m×1.0m, stainless steel) with pressure control, a micro-vapor-bubble generator, and the measurement system with sensors for oxygen (for gas mixture) and dissolved oxygen (for water) contents as well as for pressures and temperatures. The limiting extractable amount of dissolved gas from water and the oxygen concentration of the extracted gas mixture is successfully measured for demonstration through the present experimental work. Through the present study 5.9 liters of extract gas with oxygen concentration of 30% is captured out of 296 liters of water at room conditions of 17℃ and 1 atm.