Liquid-phase axial dispersion of turbulent gas–liquid co-current flow through screen-type static mixers

Abstract

This article discusses the characteristics of turbulent gas–liquid flow through tubular reactors/contactors equipped with screen-type static mixers from a macromixing perspective. The effect of changing the reactor configuration, and the operating conditions, were investigated by using four different screen geometries of varying mesh numbers. Residence time distribution experiments were conducted in the turbulent regime (4500 < Re < 29,000). Using a deconvolution technique, the RTD function was extracted to quantify the axial/longitudinal liquid-phase dispersion coefficient. The findings highlight that axial dispersion increases with an increasing flow rate and/or gas-phase volume fraction. However, regardless of the number and geometry of the mixing elements, reactor configuration, and/or operating conditions, the recorded liquid-phase axial dispersion coefficients in the presence of screens was lower than that for an empty pipe. Furthermore, the geometry of the screen was found to directly affect the axial dispersion coefficient in the reactor. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1390–1403, 2017. © 2016 American Institute of Chemical Engineers