Crystalline Fouling Studies

1983 ◽  
Vol 105 (2) ◽  
pp. 374-378 ◽  
Author(s):  
R. B. Ritter
Keyword(s):  
Mass Transfer ◽  
Surface Temperature ◽  
Aqueous Solutions ◽  
Heat Exchangers ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Induction Periods ◽  
Controlled Conditions

In a study of fouling of heat exchangers, aqueous solutions of CaSO4 and Li2SO4 were circulated through electrically heated tubes at controlled conditions. Measured induction periods and fouling rates of both salts were found to be primarily functions of the supersaturation of the solutions. Secondary correlating parameters were surface temperature for the Li2SO4 solutions and mass transfer coefficients for the CaSO4 solutions.

Comparative Study of Two-Phase Gas-Liquid Flow in the Ejector Induced Upflow and Downflow Bubble Column

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Ajay Mandal ◽  
Gautam Kundu ◽  
Dibyendu Mukherjee
Keyword(s):  
Mass Transfer ◽  
Comparative Study ◽  
Aqueous Solutions ◽  
Bubble Column ◽  
Methyl Cellulose ◽  
Stable Operation ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Mass Transfer Coefficients ◽  
Frictional Pressure Drop

A comparative study has been made on the hydrodynamics and gas-liquid mass transfer performances of upflow and downflow bubble columns. Gas-liquid distributions in the column are made by an ejector system using liquid as motive fluid and gas is used as secondary fluid for both the cases. The two-phase hydrodynamic studies have been done with water and aqueous solutions of carboxy methyl cellulose at different concentrations and air as gas phase. The volumetric mass transfer coefficients have been measured by absorbing air-carbon dioxide mixture in aqueous solutions of sodium carbonate and bicarbonate. For downflow system, experiments are carried out at natural suction of air through the ejector; whereas for upflow system, air is forced through the secondary entrance of the ejector from a high pressure tank at any desired rate. The effect of gas and liquid flowrates on gas holdup, frictional pressure drop and mass transfer coefficients have been investigated. All the experiments have been performed in the homogeneous flow regime for a stable operation.

Performance of One- and Two-Row Tube and Plate Fin Heat Exchangers

1984 ◽  
Vol 106 (3) ◽  
pp. 627-632 ◽  
Author(s):  
E. C. Rosman ◽  
P. Carajilescov ◽  
F. E. M. Saboya
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Exchangers ◽  
Local Heat Transfer ◽  
Heat Transfer Analysis ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Fin Efficiency ◽  
Heat Transfer Coefficients ◽  
Experimental Apparatus

Heat exchangers consisting of finned tubes are commonly employed in air conditioning systems, air heaters, radiators, etc. Local measurements of mass transfer coefficients on fins, obtained by Saboya and Sparrow, are very nonuniform. In the present work, an experimental apparatus was set up to measure overall heat transfer coefficients for two-row tube and plate fin heat exchangers. The obtained results, together with Shepherd’s results for one-row exchangers, are used to transform the local mass transfer coefficients into local heat transfer coefficients. A numerical two-dimensional heat transfer analysis has been performed in order to obtain the temperature distribution and fin efficiency. The influences of the Reynolds number and fin material are also analyzed.

Calculation of Heat and Mass Transfer Coefficients in a Packed Tower Operating With a Desiccant-Air Contact System

1986 ◽  
Vol 108 (2) ◽  
pp. 123-128 ◽  
Author(s):  
P. Gandhidasan ◽  
C. F. Kettleborough ◽  
M. Rifat Ullah
Keyword(s):  
Mass Transfer ◽  
Aqueous Solutions ◽  
Heat And Mass Transfer ◽  
Phase Transfer ◽  
Transfer Coefficients ◽  
Packed Tower ◽  
Mass Transfer Coefficients ◽  
Flow Rates ◽  
Heat Effects ◽  
Simultaneous Heat

Packed towers can be used for solar regeneration of aqueous solutions and dehumidification of air using aqueous solutions. These processes involve simultaneous heat and mass transfer with heat effects. In order to design a packed tower for aqueous solution-air contacting operations, heat and mass transfer coefficients for each phase are required. For the present study, aqueous calcium chloride solution is used; ceramic Raschig rings and Berl saddles are used as the packing material. In this paper air phase transfer coefficients are correlated with flow rates of air and liquid and the temperature of air, whereas liquid phase coefficients are correlated with rates of air and liquid flow, and the temperature and concentration of the liquid.

Henry's constants and mass transfer coefficients of halogenated organic pollutants in an air stripping packed column

1998 ◽  
Vol 38 (6) ◽  
pp. 287-294 ◽  
Author(s):  
Pen-C. Chiang ◽  
Chung-H. Hung ◽  
J. C. Mar ◽  
E. E. Chang
Keyword(s):  
Mass Transfer ◽  
Methylene Chloride ◽  
Packed Column ◽  
Transfer Coefficients ◽  
Chlorinated Organic Compounds ◽  
Air Stripping ◽  
Mass Transfer Coefficients ◽  
Equilibrium Partition ◽  
Henry's Constants ◽  
Chlorinated Organic

Both Henry's constants and volumetric mass transfer coefficients (KLa) of eight priority chlorinated organic compounds including 1,1-dichloroethene, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,4-dichlorobenzene in an air stripping packed column were investigated in this study. The liquid and gas phase EPICS (Equilibrium Partition in Closed System) and direct calculating methods were applied to determine the Henry's constants of VOCs. The interference of co-solute on Henry's constants was also investigated. Experimental results indicated that decrease in Henry's constants of VOCs was observed in the presence of humic acid but no apparent effect on Henry's constants was detected when there was NaCl and surfactant in solution. Four different configurations of packing media including Intalox Saddle, Super Intalox Saddle, Telleret, and Hedgehog made of polypropylene were respectively packed in the air stripping tower and investigated in the study. The dependence of hydraulic loading, air-water ratio, and configurations of packing media on mass transfer coefficients of VOCs was discussed.

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