Liquid Mixing Time in Dense Solid‐Liquid Stirred Tanks

The liquid mixing time in solid‐liquid systems is difficult to determine by quantitative and non‐intrusive methods, particularly at high solid loadings. Three methods are considered for the post‐processing of raw conductivity data collected by electrical resistance tomography (ERT) in a baffled stirred tank. A novel approach is suggested to overcome the limitations of the section‐averaged conductivity evaluations and the problems associated with the solids disturbances affecting the local conductivity data. The new approach, which is based on the classic post‐processing method devised for the mixing time determination in optically accessible stirred tanks by planar laser‐induced fluorescence, is successfully applied to the ERT data collected either under single‐phase or two‐phase conditions. The liquid mixing time in solid‐liquid stirred tanks is difficult to determine due to the effect of particle fluctuations and the opaqueness of the slurry. Different methods for the post‐processing of raw data collected by electrical resistance tomography are evaluated. A robust approach for the identification of liquid mixing times in dense solid‐liquid suspension is suggested.