Experimental study of gas evolution and dissolution process

Abstract

Changes in pressure above the saturated liquid in an airtight container can cause gas evolution and dissolution. In this study, a mathematical model was developed based on the relationship between the amount of dissolved gas and saturated solution pressure according to Henry’s law. The model can be utilized to predict changes in the pressure above the liquid, the rate of gas evolution and dissolution, and variations in free gas as the under- (over-)saturated solution reaches the saturated solution. The proposed model was built according to the solubility constant, gas-liquid volume ratio, initial equilibrium pressure of the saturated solution, and the half-life of gas evolution and dissolution. An experiment was also conducted to investigate gas evolution and dissolution; the setup included an electric vibration platform and an airtight container used to generate vibration. When the measured pressure above the liquid showed no change in the airtight container under sustained vibration, an equilibrium state was considered to be achieved. With industrial gear oil, anti-wear hydraulic oil, and water, respectively, as subjects, changes in the pressure and half-life period of gas evolution and dissolution in each liquid were measured under various gas-liquid volume ratios. Comparison against the experimental data and mathematical model pressure curves validated the models feasibility and effectiveness, and revealed that the half-life of gas evolution and dissolution decreases as the gas-liquid volume ratio increases.