Mixing Time of Surface-Active Agent Solutions
Advancing the chemical engineering fundamentals
Multifase Flows - II (T2-5b)
Keywords: mixing time, energy dissipated, surfactant solution, conductometric method, optical method
One of the basic properties of the surfactant solutions is their ability to reduce the interfacial tension and form the micelle associates. The phenomenon depends on the surfactant concentration in a solution and surfactant structure as well as on the kind and the concentration of salt present. In cationic surfactant solutions, for example ammonium quaternary salts, the spherical micelles, rod-like micelles and their unusual form called the worm-like micelles, have been formed. The worm-like micelles are formed mainly in the systems accompanied with sodium salicylate (NaSal). In literature the characteristic feature of the rod-like structures is usually connected with the fact that in a lot of cases they can substitute the high-molecular polymer additives. The last ones found the application in drag reduction of tube flow, at the crude oil output and as thickeners of the cosmetics.
In the paper the experimental studies directed on the determination of mixing time tm for tetradecylotrimethyloammonium bromide (TTAB) aqueous solutions in the agitated vessel equipped with turbine impeller of six straight blades, have been presented. Sodium bromide (NaBr) and sodium salicylate (NaSal) were used as additives promoting the micelle association process. In order to estimate the mixing time the optical method accompanied with the numerical analysis of a film, has been chosen. In optical method the pigment ultramarine (loftsman) has been used. To check the correctness of the results obtained the standard conductometric technique has been used, additionally. At the same time the power consumption has been measured.
In the study the model Newtonian fluids were distilled water and glycerin aqueous solution of concentration of 47%. The comparison of experimental results obtained for Newtonian fluid showed that they are in good accordance with Ruszkowski proposition. The results obtained were analyzed taking into account the relationship between the mixing time and an energy dissipated. It has been shown that in TTAB/NaSal aqueous solutions agitated the dumping of turbulent vortex in microscale exists. The effects of the decrease of mass transport in the tank volume and increase of the mixing time, have been observed too.
See the full pdf manuscript of the abstract.
Presented Monday 17, 16:00 to 16:20, in session Multifase Flows - II (T2-5b).
