Assessment of the Design Parameters for Wastewater Treatment by Reverse Osmosis

1999 ◽  
Vol 40 (4-5) ◽  
pp. 269-276
Author(s):  
D. Van Gauwbergen ◽  
J. Baeyens
Keyword(s):  
Reverse Osmosis ◽  
Residence Time ◽  
Volume Fraction ◽  
Transport Model ◽  
Dead Volume ◽  
Design Parameters ◽  
Flow Profile ◽  
Modelling Procedure ◽  
Mass Transport Model ◽  
Spiral Wound

A modelling procedure is presented to predict the fluxes and solute concentrations in different flows for reverse osmosis (RO) spiral-wound modules. Important underlying factors for this procedure are the osmotic pressure for various solutions, the hydrodynamic flow profile in the concentrate channel, and the intrinsic separation characteristics of the membrane material. Experiments were carried out using a flat sheet test cell to determine the parameters of the mass transport model. Results of residence time distribution (RTD)-measurements on an industrial spiral-wound module were used to determine macroscopic fluid flow regimes resulting in the definition of dead volume fraction, average residence time and Pe-number. The evaluation of the modelling procedure has been based on experimental data of an industrial membrane plant system.

scholarly journals Modelling of Fluid Flow and Residence Time Distribution in a Five-strand Tundish

2020 ◽  
Author(s):  
Dong-Yuan Sheng ◽  
Qiang Yue
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Volume Fraction ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Passive Scalar ◽  
Control Device ◽  
Dead Volume ◽  
Cfd Modelling

The quantified residence time distribution (RTD) provides a numerical characterization of mixing in the continue casting tundish, thus allowing the engineer to better understand the metallurgical performance of the reactor. This paper describes a computational fluid dynamic (CFD) modelling study for analyzing the flow pattern and the residence time distribution in a five-strand tundish. Two passive scalar transport equations are applied to separately calculate the E-curve and F-curve in the tundish. The numerical modelling results are compared to the water modelling results for the validation of the mathematical model. The volume fraction of different flow regions (plug, mixed and dead) and the intermixing time during the ladle changeover are calculated to study the effects of the flow control device (FCD) on the tundish performance. The result shows that a combination of the U-baffle with deflector holes and the turbulence inhibitor has three major effects on the flow characteristics in the tundish: i) reduce the extent of the dead volume; ii) evenly distribute the liquid streams to each strand and iii) shorten the intermixing time during the ladle changeover operation.

scholarly journals Modeling of Fluid Flow and Residence-Time Distribution in a Five-Strand Tundish

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1084 ◽  
Author(s):  
Dong-Yuan Sheng ◽  
Qiang Yue
Keyword(s):  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Volume Fraction ◽  
Fluid Dynamic ◽  
Flow Characteristics ◽  
Passive Scalar ◽  
Control Device ◽  
Dead Volume ◽  
Cfd Modeling

Quantified residence-time distribution (RTD) provides a numerical characterization of mixing in the continuous casting tundish-thus allowing the engineer to better understand the metallurgical performance of the reactor. This study describes a computational fluid dynamic (CFD) modeling study for analyzing the flow pattern and the residence-time distribution in a five-strand tundish. Two passive scalar-transport equations were applied to separately calculate the E-curve and F-curve in the tundish. The numeric modeling result were compared to water-modeling results to validate the mathematical model. The volume fraction of different flow regions (plug, mixed and dead) and the intermixing time during the ladle changeover were calculated to study the effects of the flow control device (FCD) on the tundish performance. From the results of CFD calculations, it can be stated that a combination of the U-baffle with deflector holes and the turbulence inhibitor had three major effects on the flow characteristics in the tundish: (i) to reduce the extent of the dead volume; (ii) to evenly distribute the liquid streams to each strand and (iii) to shorten the intermixing time during the ladle changeover operation.

scholarly journals Numerical simulation and industrial practice of inclusion removal from molten steel by gas bottom-blowing in continuous casting tundish

2011 ◽  
Vol 47 (2) ◽  
pp. 137-147 ◽  
Author(s):  
Z. Meijie ◽  
G. Huazhi ◽  
H. Ao ◽  
Z. Hongxi ◽  
D. Chengji
Keyword(s):  
Numerical Simulation ◽  
Residence Time ◽  
Molten Steel ◽  
Volume Fraction ◽  
Dead Volume ◽  
Inclusion Removal ◽  
Industrial Practice ◽  
Bottom Blowing ◽  
Metallographic Images ◽  
Gas Blowing

Gas blowing at the bottom of tundish is an efficient metallurgy technique in clean steelmaking. In this paper, the removal of small size inclusions in the gas bottom-blowing tundish was studied by numerical simulation and industrial practice. The residence time distribution (RTD) of molten steel in the tundish was calculated by mathematical modeling. The content of small size inclusions in the slab was analyzed using a oxygen probing and metallographic images. The results show that the molten steel characteristics obviously change when applied gas bottom-blowing, the average residence time of molten steel in the tundish prolongs more than 100s and the dead volume fraction decreases about 5%. Therefore, the removal efficiency of small size inclusions greatly increases because of bubbles attachment and long moving path. Industrial experiment results show that the average inclusions content of less than 20?m decreases more than 24%, the average overall oxygen content decreases about 15% when controlling the reasonable blowing parameters.

scholarly journals Design Optimization of a Single-Strand Tundish Based on CFD-Taguchi-Grey Relational Analysis Combined Method

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1539
Author(s):  
Dong-Yuan Sheng
Keyword(s):  
Residence Time ◽  
Grey Relational Analysis ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Volume Fraction ◽  
Single Strand ◽  
Dead Volume ◽  
Analysis Method ◽  
Relational Analysis ◽  
Grey Relational

A novel digital design methodology that combines computational fluid dynamics (CFD) modelling and Taguchi-Grey relational analysis method was presented for a single-strand tundish. The present study aimed at optimizing the flow control device in the tundish with an emphasis on maximizing the inclusion removal rate and minimizing the dead volume fraction. A CFD model was employed to calculate the fluid flow and the residence-time distribution of liquid steel in the tundish. The Lagrangian approach was applied to investigate the behavior of non-metallic inclusions in the system. The calculated residence-time distribution curves were used to analyze the dead volume fraction in the tundish. A Taguchi orthogonal array L9(3^4) was used to analyze the effects of design factors on both single and multiple responses. Moreover, for the purpose of meeting the multi-objective target functions, grey relational analysis and analysis of variance were used. The optimum positions of the weir and the dam were obtained based on the design targets. A special focus of this study was to demonstrate the capabilities of the Taguchi-Grey relational analysis method as a powerful means of increasing the effectiveness of CFD simulation.

Novel Magnetic Resonance Measurements of Fouling in Operating Spiral Wound Reverse Osmosis Membrane Modules

2021 ◽  
Vol 196 ◽  
pp. 117006 ◽  
Author(s):  
Nicholas W. Bristow ◽  
Sarah J. Vogt ◽  
Szilard S. Bucs ◽  
Johannes S. Vrouwenvelder ◽  
Michael L. Johns ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Reverse Osmosis ◽  
Reverse Osmosis Membrane ◽  
Membrane Modules ◽  
Spiral Wound

scholarly journals Modelling both the continual erosion and regeneration of discolouration material in drinking water distribution systems

2013 ◽  
Vol 14 (1) ◽  
pp. 81-90 ◽  
Author(s):  
W. R. Furnass ◽  
R. P. Collins ◽  
P. S. Husband ◽  
R. L. Sharpe ◽  
S. R. Mounce ◽  
...  
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Transport Model ◽  
Water Distribution Systems ◽  
Sensitivity Analyses ◽  
Drinking Water Distribution Systems ◽  
Proactive Management ◽  
Drinking Water Distribution ◽  
Mass Transport Model

The erosion of the cohesive layers of particulate matter that causes discolouration in water distribution system mains has previously been modelled using the Prediction of Discolouration in Distribution Systems (PODDS) model. When first proposed, PODDS featured an unvalidated means by which material regeneration on pipe walls could be simulated. Field and laboratory studies of material regeneration have yielded data that suggest that the PODDS formulations incorrectly model these processes. A new model is proposed to overcome this shortcoming. It tracks the relative amount of discolouration material that is bound to the pipe wall over time at each of a number of shear strengths. The model formulations and a mass transport model have been encoded as software, which has been used to verify the model's constructs and undertake sensitivity analyses. The new formulations for regeneration are conceptually consistent with field and laboratory observed data and have potential value in the proactive management of water distribution systems, such as evaluating change in discolouration risk and planning timely interventions.

Biofouling of spiral-wound nanofiltration and reverse osmosis membranes: A feed spacer problem

2009 ◽  
Vol 43 (3) ◽  
pp. 583-594 ◽  
Author(s):  
J.S. Vrouwenvelder ◽  
D.A. Graf von der Schulenburg ◽  
J.C. Kruithof ◽  
M.L. Johns ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Reverse Osmosis ◽  
Reverse Osmosis Membranes ◽  
Spiral Wound
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