Dispersion of supercritical carbon dioxide to [Emim][BF4] with a T-junction microtube connector

Publication date: Available online 8 March 2018 Source:Chemical Engineering and Processing - Process Intensification Author(s): Kang Qin, Kai Wang, Rui Luo, Yang Li, Tao Wang The two-phase mixtures organized by ionic liquids (ILs) and carbon dioxide (CO2) are green systems for creation and purification of fine chemicals and natural products. Owing to the very low vapor pressure of ILs, the mixture of supercritical CO2 (ScCO2) and IL has asymmetrical solubility, which is special for engineering application. However, due to the high viscosity of IL and the large density difference between IL and ScCO2, they are difficult to well mix in common chemical engineering equipment. To intensify the contact of ScCO2 and IL, we proposed a micromixing technique to disperse ScCO2 into a representative IL, 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim][BF4]) as sub-millimeter scaled bubbles. The results showed that 0.3 to 1.2 mm average diameter’s ScCO2 bubbles were cut ruptured by the continuous [Emim][BF4] phase in a 0.75 mm inner diameter T-junction connector. To further investigate the bubble generation law, the viscosity of CO2 saturated [Emim][BF4] was determined at different temperatures and pressures. The trend of size variation exhibited that the bubbles were generated from dripping flow at Ca < 0.05, but from jetting flow at Ca > 0.05. In addition, the normalized bubble diameters fit well with the two-phase microflow models obtained at atm...

Source: Chemical Engineering and Processing: Process Intensification - March 8, 2018 Category: Chemistry Source Type: research