Characterization of mixing and yield stress of pretreated wheat straw slurries used for the production of biofuels through tomography technique

Bioprocess and Biosystems Engineering - Wheat straw is a low-cost feedstock for the production of biofuel. Pretreatment process is an important stage in producing biofuels since it makes the fibers...     

Hydrodynamic performance of a single-use aerated stirred bioreactor in animal cell culture: applications of tomography,dynamic gas disengagement (DGD), and CFD

Bioprocess and Biosystems Engineering - The hydrodynamics of gas–liquid two-phase flow in a single-use bioreactor were investigated in detail both experimentally and numerically. Electrical...     

Macromixing hydrodynamic study in draft-tube airlift reactors using electrical resistance tomography

The present study summarizes results of mixing characteristics in a draft tube airlift bioreactor using ERT. This technique offers the possibility for noninvasive and nonintrusive visualization of flow fields in the bioreactor and has rarely been utilized previously to analyze operating parameters and mixing characteristics in this type of bioreactors. Several operating parameters and geometric characteristics were examined. In general, results showed that the increase in superficial gas velocity corresponds to an increase in energy applied and thus, to a decrease in mixing time. This generally corresponded to an increase in liquid circulation velocity and shear rate values. Bottom clearances and draft tube diameters affected flow resistance and frictional losses. The influence of sparger configurations on mixing time and liquid circulation velocity was significant due to their effect on gas distribution. However, the effect of sparger configuration on shear rate was not significant, with 20% reduction in shear rates using the cross-shaped sparger. Fluid viscosity showed a marked influence on both mixing times and circulation velocity especially in the coalescing media of sugar and xanthan gum (XG) solutions. Results from this work will help to develop a clear pattern for operation and mixing that can help to improve several industrial processes, especially the ones related to emerging fields of technology such as the biotechnology industry.