A maximum cell density of 35 g dry weight/l and a rosmarinic acid concentration of 3.7 g/l were obtained by maintaining the dissolved oxygen concentration above 30% air saturation, gradually raising the impeller tip speed from 34 cm/s to 72 cm/s, and keeping the aeration rate at 0.44 vvm while increasing the O2: air ratio in the gas …

In many crystallization processes and other solid-liquid reactors, solids are present in high concentrations. Often these reactors are operated in the semi-batch mode and the purity, productivity and selectivity of the reaction (and in the case of precipitation and crystallization, the size distribution and morphology too) depends on the relative …

Section snippets Experimental setup. Investigations were conducted in the experimental setup shown in Fig. 1. The stirred tank was made of transparent plexiglass for convenient observation, and the tank diameter (T) was 380 mm.The coaxial mixer inserted from the top of the stirred tank consisted of an outer wall-scraping anchor with low …

By using mixing intensification involving high solids concentration as a means to achieve process intensification for the mineral process industry is discussed here. Improving agitator energy efficiency is essential for operating at high solids concentrations.

The high concentration of carbon sources (4%) increased biomass production. ... High agitation speed and aeration rate (300 rÁmin À1, 1000 mlÁmin À1 ) enhanced the yield of astaxanthin and ...

This paper investigates the hydrodynamics and power consumption in laminar stirred vessel flow using numerical computation. The Metzner–Otto correlation was established for mixing in power-law fluids. ... Hydrodynamics of emulsion polymerization at high concentration: effect of non-Newtonian characteristics ... Hydrodynamique d'un …

Suspension of high concentration slurry. Jie Wu, Corresponding Author. Jie Wu. CSIRO, Thermal and Fluids Engineering, Highett, Victoria 3190, Australia. CSIRO, Thermal and Fluids Engineering, Highett, Victoria 3190, AustraliaSearch for more papers by this author. Yong Gang Zhu,

Stirred-suspension bioreactors are a promising modality for large-scale culture of 3D aggregates of pluripotent stem cells and their progeny. Yet, cells within these clusters experience limitations in the transfer of factors and particularly O 2 which is characterized by low solubility in aqueous media. Cultured stem cells under different O 2 …

A key hurdle with operating at a very high solids concentration is large agitation power consumption. Excessively larger power consumption is particularly problematic for …

The impact of agitation rate and sparged aeration on BM-hMSC expansion in conventional stirred tank bioreactors was assessed. It was found that a decrease in impeller speed to below NJS caused ...

The higher agitation speeds of 250 and 300 rpm could cut off mycelium and damage the cell structure owing to unbearable shear force. The DO concentration profiles were greatly different under four levels of agitation speeds (Figure 2 C). DO concentration was distinctly lower at 150 rpm, and maintained below 5% saturation for most of the time.

Semantic Scholar extracted view of "Nickel solids concentration distribution in a stirred tank" by A. Ochieng et al. ... In dense systems, agitation leads to the formation of a clear liquid layer above a solid cloud. ... Suspension and Liquid Homogenization in High Solids Concentration Stirred Chemical Reactors. W. Bujalski K. Takenaka +8 ...

In the literature the mass transfer rate OTR is usually described by a simple transport law OTR = k L a O * − O where k L a, the volumetric mass transfer coefficient, describes the capability of the aerated stirred tank bioreactors for mass transfer and (O* − O) is the driving force, the concentration difference across the liquid-side ...

Implementation of this cultivation strategy in 2.5-1 stirred-tank bioreactor cultures is investigated in the present study. ... rosmarinic acid production was found very sensitive to agitation and aeration conditions as well as dissolved oxygen concentration. A maximum cell density of 35 g dry weight/l and a rosmarinic acid concentration of 3.7 ...

Optimum solids concentration for solids suspension and solid–liquid mass transfer in agitated vessels. Chemical Engineering Research and Design 2015, 100, 148-156. DOI: …

This study focused on designing a high concentration medium agitation system for such a process using the commercial computational fluid dynamics package Fluent (V. 6.2.20) and its preprocessor ...

The agitation power required by liquid-solid suspensions of large PVC discs (4.3 mm) and sand granules (1.29 mm) in water was measured for various solids concentration, up to …

High Concentration Agitating Tank . The high concentration agitating tank is suitable for agitating the ore pulp with higher concentration, such as agitation after concentrating, mixing agitation of sand pulp etc. With agitation concentration reaching 75%. There are two impellers with upper and lower opposite spirals.

This study will propose optimum industrial agitator designs for systems handling high concentration slurries (up to 40% v/v) in the presence of gas.

In this work, suspension of high-concentration slurry in the presence of gas was investigated using different baffling configurations, particle sizes, gas flow rates, and impeller types with the goal of improving the agitation energy efficiency.

However, the reverse is true at a very high solids concentration (Wu et al., 2002), as demonstrated here that radial impellers were found to be more energy efficient to suspend solids than axial ...

Eccentric agitation in the stirred vessels still lacks study. Moreover, validation of CFD as a predictive tool requires comparison of the numerical simulation results with experimental velocity data[4~121. Most of the simulations applied to stirred vessels still use the k-e turbulence model that is based on the hypothesis of isotropic …

For treating liquid biowaste with high fluidity and low total solid concentration, the Continuously Stirred Tank Reactor presents more advantages since the daily generated wastewater could be continuously fed into the tank [15].

Stirred tank bioreactors provide high values of mass and heat transfer rates and excellent mixing. ... and different techniques for measuring the dissolved oxygen concentration can be used. ... of 0-200 rpm and continues with inefficient enhancement that starts from 300 rpm and does not reach to plateau in high agitation speeds.

CFD simulation of liquid-phase mixing in solid-liquid stirred reactor. Energy Efficient High Solids Loading Agitation for the Mineral Industry. Effect of baffle design …

This high agitation requires baffles to reduce tangential flow, ... the oil tends to get "stuck" in the middle of the reactor with high-concentration pockets off the impeller discharges, limiting oil accessibility. ... and although CFD often underestimates stirred tank mixing due to turbulence model inadequacies, ...

The fluctuations of the tracer concentration, that are shown in Fig. 6, are definitely affected by agitation, that makes the gradient of the fluctuations along the radial and the axial direction qualitatively similar to the mean values of the concentration. Download : Download high-res image (229KB) Download : Download full-size image; …

The end-product inhibition caused by high glucose concentration is widely reported [11] and it probably explains the results obtained in this work according also to the glucose concentration ...

Good solid-liquid mixing homogeneity and liquid level stability are necessary conditions for the preparation of high-quality composite materials. In this study, two rotor-stator agitators were utilized, including the cross-structure rotor-stator (CSRS) agitator and the half-cross structure rotor-stator (HCSRS) agitator. The performances of the two …

Suspension of ultrahigh concentration solids in an agitated vessel. Steven Wang, Steven Wang. Division of Earth Science and Resource Engineering, Commonwealth Scientific and Industrial Research Organization, Clayton, 3169, Australia. Search for more papers by this author.