A New Approach to Measure Diffusion Coefficients at Different Temperatures – A Simple Experiment

2008 ◽  
Vol 273-276 ◽  
pp. 789-795
Author(s):  
João M.P.Q. Delgado
Keyword(s):  
Mass Transfer ◽  
Benzoic Acid ◽  
Molecular Diffusion ◽  
Plane Surface ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Accurate Method ◽  
New Approach ◽  
Wide Range ◽  
Different Temperatures

The present work describes the mass transfer process between a moving fluid and a slightly soluble plane surface buried in a packed bed, in alignment with the direction of flow. The bed of inert particles is taken to have uniform voidage. The elliptic equation resulting from a differential mass balance was solved numerically over a wide range of the relevant parameters and the resulting values of Sherwood number are seemed to depend only of the Peclet number. Experiments measurements of mass transfer in water were performed on the dissolution of plane surfaces of 2-naphthol and benzoic acid at temperatures that differ significantly from ambient value. The soluble plane surfaces used in the experiments were made of either 2-naphthol or benzoic acid and the range of temperatures covered were 278 to 368 K, for the dissolution of 2-naphthol, and 278 to 338 K, for benzoic acid in water. The results illustrate a simple and accurate method for the measurement of the coefficient of molecular diffusion of slightly soluble solutes.

Concentration Distribution in the Wake of a Plane Surface Buried in a Porous Media in Alignment with the Flow Direction

2009 ◽  
Vol 283-286 ◽  
pp. 553-558
Author(s):  
João M.P.Q. Delgado ◽  
M. Vázquez da Silva
Keyword(s):  
Mass Transfer ◽  
Peclet Number ◽  
Numerical Solutions ◽  
Plane Surface ◽  
Flow Direction ◽  
Mathematical Expression ◽  
Mass Conservation ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Péclet Number

The present work describes the mass transfer process between a moving fluid and a slightly soluble flat surface buried in a packed bed of small inert particles with uniform voidage, by both advection and diffusion. Numerical solutions of the differential equation describing solute mass conservation were undertaken to obtain the concentration profiles, for each concentration level, the width and downstream length of the corresponding contour surface and the mass transfer flux was integrated to give the Sherwood number as a function of Peclet number. A mathematical expression that relates the dependence with the Peclet number is proposed to describe the approximate size of the diffusion wake downstream of the reactive solid mass.

Multilevel cross flow rotating packed bed to enhance gas film control mass transfer process

2021 ◽  
Vol 161 ◽  
pp. 108321
Author(s):  
Qing-Qing Duan ◽  
Zhi-Guo Yuan ◽  
You-Zhi Liu ◽  
Shan-Shan Duan ◽  
Xi-Fan Duan
Keyword(s):  
Mass Transfer ◽  
Transfer Process ◽  
Cross Flow ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Rotating Packed Bed

CFD modeling of gas–liquid mass transfer process in a rotating packed bed

2016 ◽  
Vol 294 ◽  
pp. 111-121 ◽  
Author(s):  
Yucheng Yang ◽  
Yang Xiang ◽  
Guangwen Chu ◽  
Haikui Zou ◽  
Baochang Sun ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Process ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Cfd Modeling ◽  
Liquid Mass ◽  
Rotating Packed Bed ◽  
Liquid Mass Transfer

Modeling and Analysis of Iron Mass Transfer Behaviors in Supercritical Boiler Steam-Water System

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Chao Wang ◽  
Hongyuan Li ◽  
Can Chen ◽  
Zilun Zeng ◽  
Hasan Izhar Khan ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Water System ◽  
Mass Transfer Process ◽  
Water Circulation ◽  
Working Fluid ◽  
Circulation System ◽  
Operational Parameters ◽  
Deposition Amount ◽  
Wide Range ◽  
Water Circulation System

Abstract Iron (Fe) concentration is a crucial parameter for boiler safety. However, as the working fluid circulation circuits cross each other, and the working fluid operational parameters change over a wide range, monitoring the Fe content and evaluating pipeline safety are very difficult. The mass transfer process of Fe in a complex water circulation system was described by constructing a network calculation model of Fe mass transfer in the steam-water circulation system of a supercritical boiler. The distribution of Fe and the corrosion/deposition rate in the system was calculated and analyzed. The influence of a Fe mass disturbance in single or multiple equipment on the mass distribution of Fe in the system is discussed. The results show that model calculation data is close to the operational data. Under the effect of cyclic mass transfer, both the granular and dissolved Fe cannot be ignored. During one cycle, about 36% of Fe was deposited on the system tube; however, the deposition amount in the steam generator and superheater section accounted for 81.2% of the total deposition amount, and the rest was deposited in the low-temperature pipeline. The influence of disturbance on other nodes in the network is quite different, which provides the possibility of discriminating the location of the disturbance node. The research results can provide a theoretical reference for water chemical control and safety during the operation.

Conductance of Packed Spheres in Vacuum

1973 ◽  
Vol 95 (3) ◽  
pp. 302-308 ◽  
Author(s):  
C. K. Chan ◽  
C. L. Tien
Keyword(s):  
Analytical Study ◽  
Solid Phase ◽  
Packed Bed ◽  
Infinite Plane ◽  
System Parameters ◽  
Void Fractions ◽  
Wide Range ◽  
Different Temperatures ◽  
Coated Spheres ◽  
Approximate Equations

An analytical study is presented for the heat transfer through the solid phase of a packed bed of spheres bounded by two infinite plane surfaces of different temperatures. The prediction of the conductance is based on the constriction resistance for spheres in contact. Both exact and approximate equations are derived for solid, hollow, and coated spheres and for several regular packing patterns of different void fractions. Comparisons with the available experimental data indicate that the theory is satisfactory over a wide range of applied load and system parameters.

scholarly journals Enhancement of Solubility and Mass Transfer Coefficient of Benzoic Acid Through Hydrotropy

2013 ◽  
Vol 15 (1) ◽  
pp. 46-50 ◽  
Author(s):  
D. Gnana Prakash ◽  
S. Thenesh Kumar ◽  
N. Nagendra Gandhi
Keyword(s):  
Mass Transfer ◽  
Benzoic Acid ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Enhancement Factor ◽  
Sodium Salicylate ◽  
Maximum Enhancement ◽  
Wide Range ◽  
System Temperature ◽  
Solubility Studies

The effect of hydrotropes such as sodium salicylate, sodium benzoate, and nicotinamide on the solubility and mass transfer coefficient of benzoic acid has been investigated. The solubility studies were carried out under a wide range of hydrotrope concentrations (0 to 3.0 mol/L) and different system temperatures (303K to 333K). It has been observed that the solubility and mass transfer coefficient of benzoic acid increases with an increase in hydrotrope concentration and also with system temperature. A Minimum Hydrotrope Concentration (MHC) was found essential to initiate a significant increase in the solubility and the mass transfer coefficient. The maximum enhancement factor (φs), which is the ratio of the solubility value in the presence and absence of a hydrotrope, has been determined for all sets of experimentations. The solubility of benzoic acid has been enhanced to 19.98 times in the presence of 2.5 mol/L concentration of sodium salicylate hydrotrope at 333K.The effectiveness of hydrotropes was measured in terms of Setschenow constant Ks and the highest value has been observed as 0.502 for sodium salicylate.

ANALYSIS OF EFFECT OF GAS–LIQUID INTERFACIAL DISTURBANCE ON MASS TRANSFER PERFORMANCE

2006 ◽  
Vol 13 (02n03) ◽  
pp. 279-286 ◽  
Author(s):  
HONDA WU ◽  
TSAIR-WANG CHUNG
Keyword(s):  
Mass Transfer ◽  
Surface Tension ◽  
Gas Flow ◽  
Water Drop ◽  
Triethylene Glycol ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Interfacial Instability ◽  
Transfer Performance ◽  
Absorption Performance

In order to study the mass transfer phenomena for water vapor absorbed by triethylene glycol (TEG) solution and to elucidate effect of interfacial disturbance on absorption performance, the interfacial phenomena for water drop instilling on the surface of TEG solution and mass transfer process were observed and operated in this study. Besides liquid and gas flow rates, the interfacial disturbance can also affect the mass transfer performance in the absorption system with continuous liquid phase, and the advanced mass transfer phenomena must be discussed from the interface of matter. Therefore, the surface tensions of desiccant solutions were measured to analyze the disturbed phenomena of water drop instilling on the surface of TEG solution. Since the Marangoni-Index (MI) means the maximum surface tension difference on the surface of liquid layer, the values of MI were calculated and compared with the mass transfer performance of packed-bed absorber. Generally speaking, the interfacial disturbance, resulted from the surface tension difference, would promote the contacting area of gas and liquid phases. The observation of water drop instilling on surface of TEG solution found that the interfacial disturbance existed between water drop and TEG solution, and the interfacial instability was found in the peripheral region of the water drop. On the other hand, the values of MI were increased by the increased TEG concentrations, and it can be deduced that the surface tension effect should be significant in the higher concentration of TEG solution and the interfacial disturbance would be heavier above 95 wt.% TEG solutions. Finally, the absorption performance for 95 and 96 wt.% TEG solutions were much larger than that of 90 and 88.6 wt.% TEG solutions in the operation of packed-bed absorber.

Dynamic mass transfer of textiles in rotational motions

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wenbin Li ◽  
Yunjing Jiang ◽  
Peiqing Jiang ◽  
Xin Wang
Keyword(s):  
Mass Transfer ◽  
Surface Temperature ◽  
Mass Transfer Process ◽  
Well Being ◽  
Skin Surface ◽  
Testing Time ◽  
New Approach ◽  
Content Type ◽  
Dynamic Mass ◽  
Fiber Materials

Purpose The mass transfer of textiles during movement is complicated as the energy consumption (EC) from skin, surface temperature of fabrics together with environment will work synergistically to determine the sensation and comfort of wearer. The purpose of this paper is to reveal the mass transfer in the human-textile-environment dynamic system. Design/methodology/approach With a simulated hotplate mounted on a rotational testing platform, this paper focuses on the dynamic mass transfer of a fabric so as to simulate the real-time mass transfer of clothing in movements. Findings It has been found that the EC and surface temperature (T) change against testing time, indicating the convex and concave shapes of the EC–t and T–t curves. The initial moisture regain of the fabric, rotational speed of the platform and the fiber materials of the fabric have shown a great effect on the dynamic mass transfer process. Practical implications Understanding the dynamic mass transfer of textiles will benefit the design of clothing with better comfort and will contribute to the well-being of wearers. Originality/value This work reveals the dynamic mass transfer of textiles in rotational movements. It contributes a new approach to studying the mass transfer of clothing in real service.

Experimental Values of Diffusion Coefficients of Organic Compounds in Water

2008 ◽  
Vol 273-276 ◽  
pp. 132-137
Author(s):  
João M.P.Q. Delgado
Keyword(s):  
Mass Transfer ◽  
Salicylic Acid ◽  
Cinnamic Acid ◽  
Molecular Diffusion ◽  
Packed Bed ◽  
Inert Particles ◽  
Mass Transfer Theory ◽  
Sand Particles ◽  
Experimental Values ◽  
Good Agreement

Mass transfer around a slightly soluble cylinder, aligned with the direction of liquid flow in a packed bed of sand particles, is analysed for transport by advection and molecular diffusion. The theoretical analysis applies to cylinders that are large in comparison with the inert particles, so that the bed may be treated as a continuum. Experimental measurements of mass transfer in water were carried out at temperatures that differ significantly from ambient value. The soluble cylinders used in the experiments were made of either salicylic acid or cinnamic acid and the range of temperatures covered were 278 to 343 K, for the dissolution of salicylic acid, and 278 to 328 K, for cinnamic acid in water. Using the mass transfer theory presented in this work the molecular diffusion coefficient of the two solutes was determined, and good agreement with literature values was found.

Study of Mass Transfer Characteristics of Membrane Extraction of p-Hydroxy Benzoic Acid Aqueous Solution Using Non-Porous Silicone Rubber Membrane

2013 ◽  
Vol 798-799 ◽  
pp. 227-230
Author(s):  
Wei Li Zhang ◽  
Sen Qiao ◽  
Ai Li Zhang ◽  
Ji Ti Zhou
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Benzoic Acid ◽  
Silicone Rubber ◽  
Mass Transfer Process ◽  
Membrane Extraction ◽  
Rubber Membrane ◽  
System Temperature ◽  
In Series ◽  
Acid Aqueous Solution

A kind of modules with single tubular silicone rubber membranes was combined into membrane osmosis extraction for the treatment of p-hydroxy benzoic acid aqueous solution. Mass transfer process of p-hydroxy benzoic acid through membranes was studied. Based on the resistance-in-series model, the overall mass transfer coefficient (Kov) across membrane was calculated. The effects of feed liquid flow status, system temperature and additional salt on Kov were discussed, from which the mathematical model between flow status and system temperature was obtained.

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