CHALLENGE-BASED LEARNING APPLIED TO THE DESIGN AND EXPLANATION OF CERTAIN MASS TRANSFER UNIT OPERATIONS AGAINST A PANEL OF EXPERTS

2021 ◽  
Author(s):  
María Luisa Castelló Gómez ◽  
Cristina Barrera Puigdollers ◽  
Lucía Seguí Gil ◽  
Ana Heredia Gutiérrez ◽  
Jorge García Hernández
Keyword(s):  
Mass Transfer ◽  
Unit Operations ◽  
Challenge Based Learning ◽  
Transfer Unit

scholarly journals Intensification of mass transfer with chemical reaction under conditions of concentration-capillary convection

2021 ◽  
Vol 282 ◽  
pp. 07005
Author(s):  
S.A. Ermakov ◽  
A.A. Ermakov ◽  
A.V. Mankov ◽  
Yu.R. Muratov ◽  
A.E. Koparulina
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Carbon Tetrachloride ◽  
Sodium Hydroxide ◽  
Chemical Reaction ◽  
Butyric Acid ◽  
Solid Medium ◽  
Dispersed Phase ◽  
Transfer Unit

The regularities of mass transfer with a chemical reaction in the system of aqueous solution of sodium hydroxide (solid medium) / butyric acid (transportable component) / carbon tetrachloride (dispersed phase) in spray extractors are studied. It is shown that the resulting chemocapillary instability can significantly reduce the height of the transfer unit. The conditions for the occurrence of spontaneous concentration-capillary convection during mass transfer with a chemical reaction under conditions of constrained drop movement are determined.

Influence of the Cross Sectional Area of a Separation Column Using Structured Packing

2003 ◽  
Author(s):  
Rosa H. Cha´vez ◽  
Javier de J. Guadarrama ◽  
Osbaldo Pe´rez ◽  
Abel Herna´ndez-Guerrero
Keyword(s):  
Mass Transfer ◽  
Pressure Drop ◽  
Separation Efficiency ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Structured Packing ◽  
Separation Column ◽  
Transfer Unit ◽  
The Cross

In order to determine the dimension of a separation column, hydrodynamic and mass transfer models are necessary to evaluate the pressure drop and the height of the global mass transfer unit, respectively. Those parameters are a function of the cross sectional area of the column. The present work evaluates the dependency of the pressure drop and height of the global transfer unit with respect to the cross sectional area of the column, using an absorption column with high efficiency structured packing, in order to recover SO2 in the form of NaHSO3, as an example. An optimization was done applying Two Film model which is based on the number of global mass transfer units of both gas and liquid, involving the separation efficiency in terms of the height of a global transfer unit. Structured packing, geometrically heaped in a separation column, has been achieving wider acceptance in the separation processes due to their geometric characteristics that allow them to have greater efficiency in the separation processes. Three different structured packing were evaluated in this work. The results show how ININ packing is one of the packings does the best work having the highest separation efficiency because it has the lowest height of the global mass transfer unit and Mellapak packing has the largest capacity because it manages the largest liquid and gas flows. An analysis is done with respect to the pressure drop through the system for all packings considered, and a discussion is presented for each hydrodynamic and mass transfer parameter studied.

scholarly journals Mass Transfer in Multiphasic Gas/Liquid/Liquid Systems. KLa Determination Using the Effectiveness-Number of Transfer Unit Method

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 156 ◽  
Author(s):  
Éric Dumont
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Gas Flow ◽  
Absorption Capacity ◽  
Operating Conditions ◽  
Transfer Unit ◽  
Liquid Systems ◽  
Overall Mass Transfer Coefficient

The Effectiveness-Number of Transfer Unit method (ε-NTU method) was applied to determine the overall mass transfer coefficient, KLa, of operating gas-liquid absorbers treating Volatile Organic Compounds (VOCs). This method requires the knowledge of the operating conditions (gas flow rate, QG; liquid flow rate, QL; scrubber volume V), the measurement of gaseous concentrations at the inlet, CGin, and at the outlet, CGout, of the contactor (in order to determine the effectiveness of the absorber ε) and the calculation of the Henry coefficient of the VOC between the gas and the liquid phases (HVOC). Coupled with the “equivalent absorption capacity” concept, the ε-NTU method was used to determine KLa of absorbers contacting a gas and a mixture of water and a Non Aqueous Phase, successfully. The method, validated from literature data for configurations countercurrent scrubbers and stirred tank reactors, could be used to simply determine the overall mass transfer coefficient of systems for which the standard KLa determination methods still remain non-reliable or inaccurate (viscous solvents, mixture of immiscible liquids, fermentation broths…).

Treatment of source-separated urine by a combination of bipolar electrodialysis and a gas transfer membrane

2006 ◽  
Vol 53 (3) ◽  
pp. 139-146 ◽  
Author(s):  
W. Pronk ◽  
M. Biebow ◽  
M. Boller
Keyword(s):  
Mass Transfer ◽  
Gas Phase ◽  
Ammonium Phosphate ◽  
Low Ph ◽  
Bubble Columns ◽  
Gas Transfer ◽  
Additional Mass ◽  
Hydrophobic Membrane ◽  
Bipolar Membranes ◽  
Transfer Unit

Urine contains nutrients which can be applied usefully as a fertiliser in agriculture, but the relatively high pH can lead to ammonia evaporation. Electrodialysis with bipolar membranes was combined with an additional mass transfer unit in order to render a product containing ammonium and phosphate at a low pH. In one case, the additional mass transfer unit consisted of bubble columns placed in acid and basic concentrate streams, connected with a circulating gas phase. In the other case, the unit consisted of a gas-filled (hydrophobic) membrane placed in between the circulating acid and basic concentrate streams. The results showed that ammonia was transferred through the gas phase, but also carbonate, which is present in stored urine originating from the hydrolysis of urea. Although the pH in the product stream decreases initially, it rises above pH 7 at longer operation times. This pH increase can be attributed to a combination of proton compensating effects. The use of ammonia-selective membranes for the transfer into the acid concentrate could provide a solution to generate an ammonium phosphate product at low pH and high recoveries.

Experimental Study on a Packed Bed Humidifier in an Evaporative Gas Turbine

2002 ◽  
Author(s):  
Farnosh Dalili ◽  
Mats Westermark
Keyword(s):  
Mass Transfer ◽  
Water Vapor ◽  
Gas Turbine ◽  
Boiling Point ◽  
Pilot Plant ◽  
Air Flow ◽  
Hot Water ◽  
Compressed Air ◽  
Transfer Unit ◽  
Exhaust Heat

This paper examines the performance of gas turbine cycles operating with a mixture of air and water vapor. Special attention is paid to the humidification tower, where the water vapor is added to the air. The experiments in this study have been carried out in the first evaporative gas turbine pilot plant located at Lund Institute of Technology in the southern part of Sweden. This pilot plant is based on a Volvo VT600 gas turbine with a design load of 600 kW. The compressor pressure is just above 8 bars and the intake air-flow is 3.4 kg/s. Roughly 70 percent of the compressed air is humidified in the humidification tower, which is the only humidifying device. The tower diameter is 0.7 m and the total flexible packing height is 0.9 m of a stainless steel structured packing with a specific surface area of 240 m2/m3. The number of mass transfer units in the humidifier was experimentally determined to about 3 for a packing height of 0.45 m. The height of a transfer unit from the literature data for the packing is predicted to be 0.24 m. With a packing height of 0.45 m, only about 2 transfer units are expected from the packing. However, the droplet zones above and below the packing contribute about 1 transfer unit. Thus, it is concluded that the mass transfer performance of the packing is adequately predicted by literature data. Equations are provided to adjust the height of a transfer unit for other pressures and temperatures. For full-scale plants operating at higher pressures and temperatures it is suggested that the high quality exhaust heat, (temperatures above the boiling point) is recovered in a boiler and injected as steam. The remaining part of the exhaust heat, (temperatures below the boiling point) is used to produce hot water for a relatively small humidification tower using only a portion of the compressed air flow.

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