Influence of mass transfer resistance on overall nitrate removal rate in upflow sludge bed reactors

Chemosphere ◽  
2006 ◽  
Vol 65 (1) ◽  
pp. 148-158 ◽  
Author(s):  
Wen-Huei Ting ◽  
Ju-Sheng Huang
Keyword(s):  
Mass Transfer ◽  
Removal Rate ◽  
Nitrate Removal ◽  
Mass Transfer Resistance ◽  
Transfer Resistance

Performance Improvement of Mass Transfer Through Membrane Using Ultrasound for HVAC Application

2020 ◽  
Author(s):  
A. Gurubalan ◽  
Patrick J. Geoghegan ◽  
M. P. Maiya ◽  
Carey J. Simonson
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Removal Rate ◽  
Packed Bed ◽  
Transfer Performance ◽  
Mass Transfer Resistance ◽  
Additional Mass ◽  
Transfer Resistance ◽  
Air Interface ◽  
Air Conditioning Systems

Abstract Liquid desiccant dehumidification is one of the energy-efficient alternatives to conventional air conditioning systems for humidity control. Membrane dehumidifier is preferred to avoid the desiccant carryover, which occurs in a conventional packed bed dehumidifier. However, its mass transfer performance is lesser than that of the packed bed dehumidifier. This is due to additional mass transfer resistance of the membrane between the air and desiccant. It is found that the resistance by the boundary layer formed at the membrane-air interface accounts for a significant portion of the overall mass transfer resistance. Breaking of such boundary layer using ultrasound is an attractive technique to reduce the resistance. The present study experimentally investigates the influence of ultrasound on the mass transfer performance of a membrane humidifier. Subsequently, with the experimental results of the humidifier, the effect of ultrasound on the performance of the membrane dehumidifier is numerically studied. The performances of humidifier and dehumidifier are presented in terms of moisture addition or removal rate and latent effectiveness. It is found that the vibration due to ultrasound enhances the performance of the membrane dehumidifier by 1.5 times.

Analysis of Heat and Mass Transfer Between a Desiccant-Air System in a Packed Tower

1987 ◽  
Vol 109 (2) ◽  
pp. 89-93 ◽  
Author(s):  
P. Gandhidasan ◽  
M. Rifat Ullah ◽  
C. F. Kettleborough
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Heat And Mass Transfer ◽  
Packing Material ◽  
Mass Transfer Resistance ◽  
Liquid Desiccant ◽  
Governing Equations ◽  
Packed Tower ◽  
Transfer Resistance ◽  
Steady State Model

Heat and mass transfer analysis between a desiccant-air contact system in a packed tower has been studied in application to air dehumidification employing liquid desiccant, namely calcium chloride. Ceramic 2 in. Raschig rings are used as the packing material. To predict the tower performance, a steady-state model which considers the heat and mass transfer resistances of the gas phase and the mass transfer resistance of the liquid phase is developed. The governing equations are solved on a digital computer to simulate the performance of the tower. The various parameters such as the effect of liquid concentration and temperature, air temperature and humidity and the rates of flow of air and liquid affecting the tower performance have been discussed.

scholarly journals Modeling of the adsorption kinetics of zinc onto granular activated carbon and natural zeolite

2006 ◽  
Vol 71 (8-9) ◽  
pp. 957-967 ◽  
Author(s):  
Ljiljana Markovska ◽  
Vera Meshko ◽  
Mirko Marinkovski
Keyword(s):  
Mass Transfer ◽  
Activated Carbon ◽  
Simulation Study ◽  
Natural Zeolite ◽  
Granular Activated Carbon ◽  
Model Parameters ◽  
Mass Transfer Resistance ◽  
External Mass Transfer ◽  
Transfer Resistance ◽  
Kinetics Of

The isotherms and kinetics of zinc adsorption from aqueous solution onto granular activated carbon (GAC) and natural zeolite were studied using an agitated batch adsorber. The maximum adsorption capacities of GAC and natural zeolite towards zinc(II) from Langmuir adsorption isotherms were determined using experimental adsorption equilibrium data. The homogeneous solid diffusion model (HSD-model) combined with external mass transfer resistance was applied to fit the experimental kinetic data. The kinetics simulation study was performed using a computer program based on the proposed mathematical model and developed using gPROMS. As the two-mass transfer resistance approach was applied, two model parameters were fitted during the simulation study. External mass transfer and solid phase diffusion coefficients were obtained to predict the kinetic curves for varying initial Zn(II) concentration at constant agitation speed and constant adsorbent mass. For any particular Zn(II) - adsorbent system, k f was constant, except for the lowest initial concentration, while D s was found to increase with increasing initial Zn(II) concentration.

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