Modeling of Microbubble Flow and Coalescence Behavior in the Contact Zone of a Dissolved Air Flotation Tank Using a Computational Fluid Dynamics–Population Balance Model

2019 ◽  
Vol 58 (36) ◽  
pp. 16989-17000 ◽  
Author(s):  
Aqiang Chen ◽  
Wensan Yang ◽  
Shujun Geng ◽  
Fei Gao ◽  
Taobo He ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Contact Zone ◽  
Population Balance ◽  
Balance Model ◽  
Population Balance Model ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

Flotation efficiency of activated sludge flocs using population balance model in dissolved air flotation

2006 ◽  
Vol 23 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Heung-Joe Jung ◽  
Jae-Wook Lee ◽  
Do-Young Choi ◽  
Seong-Jin Kim ◽  
Dong-Heui Kwak
Keyword(s):  
Activated Sludge ◽  
Population Balance ◽  
Balance Model ◽  
Population Balance Model ◽  
Dissolved Air Flotation ◽  
Sludge Flocs ◽  
Air Flotation ◽  
Dissolved Air

Modelling of Bubble Growth in Supersaturated Solution Using Computational Fluid Dynamics - Population Balance Model (CFD-PBM) Approach

2015 ◽  
Vol 362 ◽  
pp. 200-208
Author(s):  
Zhen Hong Ban ◽  
Kok Keong Lau ◽  
Mohd Shariff Azmi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Bubble Size ◽  
Bubble Growth ◽  
Population Balance ◽  
Balance Model ◽  
Population Balance Model ◽  
Supersaturated Solution ◽  
Supersaturation Ratio ◽  
Growth Phenomenon

The bubble growth modelling in a supersaturated solution is difficult to be accomplished as it requires coupling of many interrelated hydrodynamics and mass transfer parameters which include pressure drop, supersaturation ratio, bubble size, etc. In the current work, all these factors have been taken into consideration to predict bubble growth in a supersaturated solution using Computational Fluid Dynamics (CFD) – Population Balance Model (PBM) approach. A classical bubble growth model has been used in the simulation. The bubble growth rate was successfully validated with experimental data in terms of bubble size. The attempt to simulate the bubble growth phenomenon of more than a single bubble condition has also been presented. The outcome of this approach is expected to be applied in many engineering areas.

scholarly journals Modeling the Separation of Microorganisms in Bioprocesses by Flotation

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 184 ◽  
Author(s):  
Stefan Schmideder ◽  
Christoph Kirse ◽  
Julia Hofinger ◽  
Sascha Rollié ◽  
Heiko Briesen
Keyword(s):  
Fluid Dynamics ◽  
Separation Efficiency ◽  
Algebraic Model ◽  
Balance Model ◽  
Separation Processes ◽  
Dissolved Air Flotation ◽  
Computational Fluid Dynamics Cfd ◽  
Air Flotation ◽  
Cell Size Distributions ◽  
Dissolved Air

Bioprocesses for the production of renewable energies and materials lack efficient separation processes for the utilized microorganisms such as algae and yeasts. Dissolved air flotation (DAF) and microflotation are promising approaches to overcome this problem. The efficiency of these processes depends on the ability of microorganisms to aggregate with microbubbles in the flotation tank. In this study, different new or adapted aggregation models for microbubbles and microorganisms are compared and investigated for their range of suitability to predict the separation efficiency of microorganisms from fermentation broths. The complexity of the heteroaggregation models range from an algebraic model to a 2D population balance model (PBM) including the formation of clusters containing several bubbles and microorganisms. The effect of bubble and cell size distributions on the flotation efficiency is considered by applying PBMs, as well. To determine the sensitivity of the results on the model assumptions, the modeling approaches are compared, and suggestions for their range of applicability are given. Evaluating the computational fluid dynamics (CFD) of a dissolved air flotation (DAF) system shows the heterogeneity of the fluid dynamics in the flotation tank. Since analysis of the streamlines of the tank show negligible back mixing, the proposed aggregation models are coupled to the CFD data by applying a Lagrangian approach.

Research on the CFD numerical simulation and process optimization of countercurrent–cocurrent dissolved air flotation

2019 ◽  
Vol 68 (5) ◽  
pp. 325-336
Author(s):  
Yonglei Wang ◽  
Wei Liu ◽  
Liping Tian ◽  
Ruibao Jia ◽  
Zhenqi Du ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Contact Zone ◽  
Process Optimization ◽  
Operating Conditions ◽  
Cocurrent Flow ◽  
Dissolved Gas ◽  
Dissolved Air Flotation ◽  
Simulation Results ◽  
Air Flotation ◽  
Dissolved Air

Abstract The countercurrent–cocurrent dissolved air flotation (CCDAF) process is a new type of air flotation process integrating countercurrent collision and cocurrent flow adhesion processes. The structural form of the CCDAF tank and its process parameters are the required conditions to achieve countercurrent collision and cocurrent adhesion. In this study, eight CCDAF tank process models were established with a flow rate of 0.5 m3/h. Flow field numerical simulation and process optimization of a CCDAF tank was conducted using Fluent software. The simulation results show that the optimal conditions for the CCDAF process are as follows: contact zone ascending velocity 10 mm/s, separation zone separation velocity 1.5 mm/s, dissolved gas pressure 0.45 MPa, and recirculating dissolved-gas distribution ratio R1/R2 1:1. Under these operating conditions, the flow state in the flotation tank is the most stable and the gas in the contact zone is evenly distributed. According to the simulation results, a 5 m3/h pilot plant was built. The structural dimensions were: B × L × H = 1,020 mm × 1,300 mm × 1,350 mm. The test results show that the CCDAF has a significant decontamination effect and is clearly superior to the cocurrent flow DAF process and countercurrent flow DAF process.

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