scholarly journals Temperature Coefficient for Modeling Denitrification in Surface Water Sediments Using the Mass Transfer Coefficient

2010 ◽  
Vol 53 (2) ◽  
pp. 465-474
Author(s):  
T. W. Appelboom ◽  
G. M. Chescheir ◽  
F. Birgand ◽  
R. W. Skaggs ◽  
J. W. Gilliam ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Surface Water ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Temperature Coefficient

Application of ScaleGuard® at reverse osmosis and nanofiltration installations

2003 ◽  
Vol 3 (5-6) ◽  
pp. 133-138 ◽  
Author(s):  
S.G.J. Heijman ◽  
H. Folmer ◽  
F. Donker ◽  
B.M. Rietman ◽  
J.C. Schippers
Keyword(s):  
Mass Transfer ◽  
Surface Water ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Reverse Osmosis ◽  
Early Stage ◽  
Inorganic Compounds ◽  
Full Scale ◽  
Reverse Osmosis Plant ◽  
On Line

ScaleGuard® is a continuous on-line monitor that detects scaling at an early stage when fed with the concentrate of a pilot- or full-scale plant. Scaling is observed in the ScaleGuard before it occurs in the full-scale installation. The ScaleGuard is used to optimize the recovery of two full-scale plants: one reverse osmosis plant treating pretreated surface water and one nanofiltration plant treating anaerobic groundwater. Based on the results of the ScaleGuard the conversion of both the reverse osmosis plant and the nanofiltration plant has been increased from 80% to 82%. The interpretation of the results of the ScaleGuard which was connected with the reverse osmosis plant was not unambiguous. This was due to the mass transfer coefficient decline in the ScaleGuard which could not be attributed to scaling. Results in the nanofiltration plant did not give room for any doubt. In addition, safe supersaturation ratios were derived from experience in pilot- and full-scale plants using anti-scalants for seven sparingly soluble inorganic compounds.

Absorption of oxygen into solutions of polymers

1986 ◽  
Vol 51 (10) ◽  
pp. 2127-2134 ◽  
Author(s):  
František Potůček ◽  
Jiří Stejskal
Keyword(s):  
Mass Transfer ◽  
Aqueous Solutions ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Liquid Flow ◽  
Flow Curve ◽  
Liquid Flow Rate ◽  
Polymer Concentration ◽  
Newtonian Liquids

Absorption of oxygen into water and aqueous solutions of poly(acrylamides) was studied in an absorber with a wetted sphere. The effects of changes in the liquid flow rate and the polymer concentration on the liquid side mass transfer coefficient were examined. The results are expressed by correlations between dimensionless criteria modified for non-Newtonian liquids whose flow curve can be described by the Ostwald-de Waele model.

scholarly journals Development of mass and heat transfer coupled model of hollow fiber membrane for salt recovery from brine via osmotic membrane distillation

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Sher Ahmad ◽  
Gabriela Vollet Marson ◽  
Waheed Ur Rehman ◽  
Mohammad Younas ◽  
Sarah Farrukh ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Heat And Mass Transfer ◽  
Hollow Fiber ◽  
Hollow Fiber Membrane ◽  
Membrane Distillation ◽  
Fiber Membrane ◽  
Salt Recovery ◽  
Osmotic Solution

Abstract Background In this research work, a coupled heat and mass transfer model was developed for salt recovery from concentrated brine water through an osmotic membrane distillation (OMD) process in a hollow fiber membrane contactor (HFMC).The model was built based on the resistance-in-series concept for water transport across the hydrophobic membrane. The model was adopted to incorporate the effects of polarization layers such as temperature and concentration polarization, as well as viscosity changes during concentration. Results The modeling equations were numerically simulated in MATLAB® and were successfully validated with experimental data from literature with a deviation within the range of 1–5%. The model was then applied to study the effects of key process parameters like feed concentrations, osmotic solution concentration, feed, and osmotic solution flow rates and feed temperature on the overall heat and mass transfer coefficient as well as on water transport flux to improve the process efficiency. The mass balance modeling was applied to calculate the membrane area based on the simulated mass transfer coefficient. Finally, a scale-up for the MD process for salt recovery on an industrial scale was proposed. Conclusions This study highlights the effect of key parameters for salt recovery from wastewater using the membrane distillation process. Further, the applicability of the OMD process for salt recovery on large scale was investigated. Sensitivity analysis was performed to identify the key parameters. From the results of this study, it is concluded that the OMD process can be promising in salt recovery from wastewater.

scholarly journals Hydrodynamics and Mass Transfer in a Concentric Internal Jet-Loop Airlift Bioreactor Equipped with a Deflector

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4329
Author(s):  
Radek Šulc ◽  
Jan Dymák
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Liquid System ◽  
Gas Holdup ◽  
Gas Velocity ◽  
Liquid Phase Mass Transfer ◽  
Homogenization Time ◽  
Standard Design ◽  
Superficial Gas Velocity

The gas–liquid hydrodynamics and mass transfer were studied in a concentric tube internal jet-loop airlift reactor with a conical bottom. Comparing with a standard design, the gas separator was equipped with an adjustable deflector placed above the riser. The effect of riser superficial gas velocity uSGR on the total gas holdup εGT, homogenization time tH, and overall volumetric liquid-phase mass transfer coefficient kLa was investigated in a laboratory bioreactor, of 300 mm in inner diameter, in a two-phase air–water system and three-phase air–water–PVC–particle system with the volumetric solid fraction of 1% for various deflector clearances. The airlift was operated in the range of riser superficial gas velocity from 0.011 to 0.045 m/s. For the gas–liquid system, when reducing the deflector clearance, the total gas holdup decreased, the homogenization time increased twice compared to the highest deflector clearance tested, and the overall volumetric mass transfer coefficient slightly increased by 10–17%. The presence of a solid phase shortened the homogenization time, especially for lower uSGR and deflector clearance, and reduced the mass transfer coefficient by 15–35%. Compared to the gas–liquid system, the noticeable effect of deflector clearance was found for the kLa coefficient, which was found approx. 20–29% higher for the lowest tested deflector clearance.

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