Enhancing Impeller Power Efficiency and Solid–Liquid Mass Transfer in an Agitated Vessel with Dual Impellers through Process Intensification

Abstract

The effects of high volumetric solids concentration (C V), impeller type, and baffles on the impeller power input required for solids suspension and dispersion and the solid–liquid mass transfer coefficient (k SL) were studied in this work using an agitated vessel with dual impellers for the purpose of process intensification. It was found that at C V = 0.2 (v/v), the impeller power consumption required for solids suspension per unit mass solids (εJS = P JS/M S) is minimized while at the same time achieving maximum k SL values. Overall, it was observed that process intensification could be achieved using two radial flow impellers in a taller vessel under unbaffled conditions. A case study highlighting the benefits of adopting some of this study’s recommendations is presented. Mathematical correlations proposed to estimate εJS, impeller power consumption for solids dispersion, and k SL as a function of C V were found to fit experimental data reasonably well.

Another Critical Look at Three-Phase Catalysis

“…79,80 Modeling of gas-liquid mass transfer 81 was performed using an Euler-Lagrange approach 82 and CFD. 83 Additionally, liquid-solid mass transfer 84,85 and solid-liquid mass transfer 86 were also reported in STR.…”

Numerical Study on the Synergistic Mechanism of Coaxial Mixers in Dense Solid–Liquid Mixing Systems

“…To reduce the just-suspended power at heavy solid concentrations, Wang et al 7 and Wu et al 9 recommend adopting mixers with a higher power number, and removing baffles from the stirred tank was also confirmed to be an effective way. 10,11 Additionally, several researchers established numerical models of dense solid−liquid mixing, 12−16 which all highlighted the significance of solid collisions on predicted values. Although research on dense solid−liquid mixing was conducted extensively, the objects of the above studies were limited to single-shaft mixers.…”

“…Most research studies focus on dilute slurry conditions, − while the challenges of dense solid–liquid mixing have already attracted universal attention. − Power consumption is one of the important indicators for evaluating the performance of mixers, and Wu et al discovered that with growing amounts of solid content, the stirring power would increase exponentially. To reduce the just-suspended power at heavy solid concentrations, Wang et al and Wu et al recommend adopting mixers with a higher power number, and removing baffles from the stirred tank was also confirmed to be an effective way. , Additionally, several researchers established numerical models of dense solid–liquid mixing, − which all highlighted the significance of solid collisions on predicted values. Although research on dense solid–liquid mixing was conducted extensively, the objects of the above studies were limited to single-shaft mixers.…”

Energy efficiency research of fermentation medium agitation in manufacturing of microbiological plant protection products

“…The issue of energy effi ciency improvement of fermentation medium agitation is not suffi ciently described in scientifi c literature. Current studies are mainly related to the most common mechanical method of agitation [6][7][8]. Energy effi ciency improvement is envisaged due to the power consumption reduction by the optimization of fermenter's design [6,7] or maintenance of experimentally determined optimal conditions for agitators of such type [8].…”