Simulation and Experimental Investigation of Power Consumption, Gas Dispersion and Mass Transfer Coefficient in a Multi-Phase Stirred Bioreactor

Abstract

Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the mass transfer coefficient, which could be used to evaluate the mass transfer rate, was determined by gas holdup, bubble diameter and power consumption. Therefore, a three-phase Eulerian equation with k-ε turbulence model and additional models of two bubble diameter, a torque and a mass transfer coefficient were applied in the simulation. The simulation results were validated with experimental data and used to analyze the spatial distribution of the mass transfer coefficient. The results demonstrated that the simulation and experimental data of Sauter mean bubble diameter and power number were in good agreement and the simulation results of the mass transfer coefficient were agree with the values calculated by an empirical correlation. The Davoody model can be strongly recommended for further simulation of the bubble diameter, and the gas holdup and mass transfer coefficient were very unevenly distributed in the lower zone. Hence, the lower impeller clearance should be considered.

Optimization of a Multiphase Mixed Flow Field in Backfill Slurry Preparation Based on Multiphase Flow Interaction

“…This model is based on the classic Schiller and Naumann model with the effect on the turbulence added. The equation is as follows: f = C D R e 24 …”

“…This model is based on the classic Schiller and Naumann model with the effect on the turbulence added. The equation is as follows:42 the equation, C D refers to the drag coefficient and can be calculated by the following equation:…”

Study on the Flow Field Characteristics of a Liquid–Solid–Solid Three-Phase System and the Influence of a Draft Tube in a Stirred Reactor

“…The agitation power is usually calculated by measuring the torque in the experiment, and the key to calculate the power is to obtain the power number. ,, There are many factors affecting the power number, including impeller diameter, blade width, inclination angle, rotating speed, reactor diameter, liquid depth, baffle number, liquid density, viscosity, and other factors. − At present, there are many research studies on the power of homogeneous agitation. The agitation power can be calculated based on the Rushton diagram or mathematical correlation. − Since these conclusions are all obtained by experiments, and the experiments are carried out under certain limited conditions, the agitators must be the same and satisfy similar geometric conditions when using these diagrams and formulas.…”