-The effect of elevated pressure on the stability of the homogeneous bubbly flow regime in a gas-liquid bubble column is examined. Experiments were performed in a 0.15 m diameter bubble column operated at pressures in the range 0.1-1.3 MPa with nitrogen as the gas phase and water as the liquid phase. The transition from homogeneous to heterogeneous flow regime was determined by two procedures. ...

The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp overflow to concentrate lander, maintenance and control problems. An attempt was exerted by im...

In this paper attempts are made to address how bubble behaviour in a batch oscillatory ba'ed column (OBC) contributes to the overall measured enhancement in mass transfer. A CCD camera is used to measure the bubble size distribution and the gas hold-up in the OBC. The experimental results of Sauter mean diameter and gas hold-up are correlated as a function of the power dissipation and super5cia...

We report a parallel algorithm applicable to a Euler–Lagrange model embedding four-way coupling. The model describing the dispersed phase dynamics accounts for bubble–bubble collisions and is parallelized using a mirror domain technique while the pressure Poisson equation for the continuous phase is solved using a domain decomposition technique implemented in the PETSc library [S. Balay, K. Bus...

Bursting of bubbles at an air/liquid interface is a familiar occurrence relevant to foam stability, cell cultures in bioreactors and ocean–atmosphere mass transfer. In the latter case, bubble-bursting leads to the dispersal of sea-water aerosols in the surrounding air. Here we show that bubbles bursting at a compound air/oil/water-with-surfactant interface can disperse submicrometre oil droplet...

Lu Han and Muthanna H. Al-Dahhan A gaseous tracer technique and procedures were developed and implemented to measure the axial dispersion of gas phase in a slurry bubble column reactor using air-water-glass beads (100ìm). Residence time distribution curves were obtained by measuring the response of gaseous tracer pulse input. The gas phase axial dispersion coefficient, Dg, was determined from m...

Oxygen gas-liquid mass transfer coefficient was measured in a gas-induced pulsating flow bubble column. Pulsating amplitude had a great influence on kla under pulsating state of equal base flow and pulsating flow, which was enhanced up to 30 % compared with that under steady state; however, it had a negative effect on mass transfer under a fixed low base flow. It was also found that kla had a n...

Gibberellic acid (GA3) is an important phytohormone, a member of gibberellins family, which acts as a promoter and regulator of plant growth. This study aimed to evaluate GA3 production by Fusarium moniliforme LPB03 and Gibberella fujikuroi LPB06 using different techniques of fermentation, solid state fermentation (SSF), submerged fermentation (SmF), and semisolid state fermentation (SSSF), and...

The semicontinuous and continuous production of pharmaceutically useful ergot peptides with immobilized Claviceps purpurea could be demonstrated. A key aspect was the presence of high concentrations of CaCl(2) (96.9 mM) to give marked prolongation of the productive phase, and cultivation in a bubble column reactor became possible. Restriction of the phosphate supply avoided an otherwise problem...