modified bubble column extraction with ultrasonic bath (bce-ub) method was used to extract atropine from the stem and leaves of atropa belladonna. optimum condition were obtained with kamada solvent which was chloroform-methanol-ammonia 15:15:1(v/v/v) as extraction solvent, the particle size of  less than  350 µm, an extraction time of 23.95 min, a liquor to material ratio of 15.08 ml/g and  an...

Numerical simulations of the gas-liquid bubbly flow in a bubble column were conducted with the commercial CFD package CFX-4.4 to investigate the performance of three models (Pfleger and Becker, 2001; Sato and Sekoguchi, 1975; Troshko and Hassan, 2001) to account for the bubble-induced turbulence in the k-ε model. Furthermore, the effect of two different interfacial closure models was investigat...

simulation using a commercially available computational fluid dynamics package (FLUENT) were adopted to investigate complex behavior involving hydrodynamics and ferrous biological oxidation in a gas–liquid bubble column reactor. By combining the hydrodynamics and chemical species transport equations, the velocity field, air volume fraction and ferrous biooxidation rate in the column were simula...

An in-depth numerical study has been carried out to investigate a high-pressure commercial scale (2–8 meter diameter) slurry bubble column reactor (SBCR). Typical superficial gas velocities are in the range of 0.5–3 m/s, and overall vapor hold-ups are in the range of 0.45–0.85. The study revealed that steady compartmental reaction models do not match plant data when reaction time constants are ...

In slurry bubble column reactors, catalyst particles may adhere to gas bubbles. Thus, mass transfer limited reactions can be significantly improved either by increasing G-L mass transfer coefficient kL or specific surface area a. The scope of this work is to study the influence of model parameters on coalescence and G-L mass transfer, in order to develop new rules for design and scale-up of slu...

The dynamic behavior of ozonation with pollutants in a countercurrent bubble column is studied for the model establishment. Bubble columns have been widely used for an ozonation system in the plants and laboratories. In addition, a countercurrent bubble column has been commonly recommended than a cocurrent one because it has a higher ozone transfer efficiency. Therefore, the investigation of th...

In this investigation, CFD simulation is presented to study the hydrodynamic of bubbly flow and mass transfer in bubble column using EulerianEulerian Multifluid approach with a standard kε turbulence model. unsteady state method for modeling the multiphase flow and mass transfer from air to de-aerated water and the column hydrodynamics. Understanding the complexity of the fluid dynamics and mas...

Separation of proteins from whey; namely α – Lactoglobulin and β – Lactalbumin was obtained using the bubble foam column technique. Two types of whey were conducted in this study; yogurt whey and cheese whey. The effect of gas flow-rate and the height of the whey (liquid holdup) inside the column were studied at room temperature and at constant pH of whey. Whey used here obtained from local dai...