Modelagem matemática e física da influência da tensão interfacial na flotação

Abstract

Oil is the main energy source for most countries, but its extraction process results in the production of large quantities of water, which must be treated before disposal to comply with regulations due to the concentration of oil present. Among the treatments for refining the produced water is flotation, which involves the addition of microbubbles to remove remaining oil droplets from the aqueous medium. The removal of oil droplets occurs partly due to the formation of stable compound droplets derived from the interaction between droplets and bubbles and their adhesion. One of the variables in the flotation process is interfacial tension, an aspect that is understudied in this specific context. This work aims to compare experimental results conducted with and without surfactants in the water within a model flotation device, thereby examining the influence of interfacial tension on the formation of aggregates. For this experiment, oil droplets are injected at a flow rate of 0.6 l/h, bubbles are also injected at 0.6 l/h, while water is injected as a continuous medium at 55 l/h. The method of bubble generation is due to depressurization, resulting in the release of dissolved gas in water at pressures of 4.25 bar. The droplet generation method is by shear. The study was conducted through the acquisition and analysis of images, showing that the reduction of interfacial tension influenced flotation; however, the compound drops formed were not sufficiently stable, leading to recurrent cases where the bubble and the droplet detached after aggregation. The work presents a complementary view to the study of compound drop formation, suggesting a potential area of interest for deeper studies in the future, focusing on interfacial tension as a variable in the process.